Pathogens and Immune Response of Cephalopods

7/24/2019 Pathogens and Immune Response of Cephalopods

1/9

Special issue: Cephalopod Biology

Pathogens and immune response of cephalopods

Sheila Castellanos-Martnez, Camino Gestal ,1

Instituto de Investigaciones Marinas (IIM-CSIC), Vigo, Spain

a b s t r a c ta r t i c l e i n f o

Article history:

Received 4 December 2011

Received in revised form 2 May 2012

Accepted 25 January 2013

Keywords:

Cephalopods

Diseases

Genomic approach

Innate immune response

Pathogens

Symbionts

Cephalopod mollusks are an important marine resource for sheries, and have received marked attention for

studies on organismal biology; they are also good candidates for aquaculture. Wild and reared cephalopods

are affected by a wide variety of pathogens, mainly bacteria, protozoa and metazoan parasites. Cephalopods

do not have acquired immunity and immunological memory; therefore vaccination cannot be used to protectthem against infectious diseases. Their defense mechanisms rely only on their innate immunity. In this re-

view, we will summarize and update knowledge on the most common pathogens, the diseases they cause,

and on symbionts. In addition, we provide a general overview of the cephalopod immune system, response

to pathogens with a short discussion on the gene expression involved in the immune response by these

animals.

2013 Elsevier B.V. All rights reserved.

1. Introduction

Scientic interest for cephalopods is increased over the last century

for, at least, a couple of reasons:i. their value as experimental animals

for biomedical and behavioral research (for review see for example:Grant et al., 2006; Hanlon and Messenger, 1996; Hochner, 2008;

Hochner et al., 2006; Mather, 1995); ii. their position in the world

marked as a major shery resource (e.g.Boyle and Rodhouse, 2005).

Since the decline of traditional sheries (Balguerias et al., 2000;

Caddy and Rodhouse, 1998), cephalopods have gained attention in

aquaculture practice. Among other cephalopods, Octopus vulgaris has

been considered the candidate species in European aquaculture be-

cause of its easy acclimatization to farming conditions, its rapid growth

and its good value for the market (Vaz-Pires et al., 2004). The octopus

on-growing is currently developed in Galicia (NW Spain) on an indus-

trial scale (Garcia and Garcia, 2011; Garcia et al., 2004).

Despite the benets, one of the disadvantages of aquaculture is the

increase in the incidence of pathologies produced by bacteria and/or

transmissible parasites that could be a serious risk for the production.

On the other hand, the EU Directive on the use of animals for experi-

mental purposes European Parliament and Council of the European

Union, 2010, requires capture of animals from the wild to be mini-

mized. Thus, it becomes urgent that practices of culturing animals

be further expanded. Finally, an important outcome of the Directive

2010/63/EU is that appropriate care and maintenance of cephalopods

for research purposes will require proper knowledge and practice in

terms of assessment of health and disease prevention of the animals.

These considerations prompted this review.Cephalopods, like the rest of mollusks, lack a specic immune re-

sponse and do not posses immunological memory. Thus, they rely on

the innate immune system in facing with diseases (for review see:Ford,

1992; Gestal et al., 2008; Malham and Runham, 1998). Despite the in-

creasing economic and scientic importance of cephalopods, the research

effort on pathogens and pathologies suffered by cephalopods is less than

54% of the effort directed to other commercially important marine re-

sources (Pascual and Guerra, 2001). Similarly, available knowledge on

the immune response in these animals is still limited (Ford, 1992).

2. Common pathogenic agents

Knowledge on the most common pathogenic agents identied in

cephalopods has been reviewed in the classic Diseases of Marine

Animalswith contributions byHanlon and Forsythe (1990a, b)and

Hochberg (1990).

2.1. Bacteria

Bacterial infections have been reported, for example, on the squid's

ns after injuries produced during capture (Hanlon et al., 1983), or on

lesions suffered by octopus in captivity (Hanlon et al., 1984). This may

cause the spread of the infection to other organisms in the tank or in

the system. Hanlonet al.(1984) observed skin ulcersin rearedOctopus

joubini and Octopus briareus; these appearedrst on thedorsal mantle

and then spread to head and arms. Four stagesof ulceration have been

Journal of Experimental Marine Biology and Ecology 447 (2013) 1422

This article is part of a special issue on Cephalopod Biology published under the

auspices of CephRes-ONLUS (www.cephalopodresearch.org).

Corresponding author. Tel.: + 34 986 231930x285.

E-mail address:[email protected](C. Gestal).1 Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Cientcas,

Eduardo Cabello 6, 36208 Vigo, Spain. Tel.: +34 986 231930x285.

0022-0981/$ see front matter 2013 Elsevier B.V. All rights reserved.

http://dx.doi.org/10.1016/j.jembe.2013.02.007

Contents lists available at SciVerse ScienceDirect

Journal of Experimental Marine Biology and Ecology

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / j e m b e
http://-/?-http://-/?-http://dx.doi.org/10.1016/j.jembe.2013.02.007http://dx.doi.org/10.1016/j.jembe.2013.02.007http://dx.doi.org/10.1016/j.jembe.2013.02.007http://www.cephalopodresearch.org/mailto:[email protected]://dx.doi.org/10.1016/j.jembe.2013.02.007http://www.sciencedirect.com/science/journal/00220981http://crossmark.crossref.org/dialog/?doi=10.1016/j.jembe.2013.02.007&domain=pdfhttp://www.sciencedirect.com/science/journal/00220981http://dx.doi.org/10.1016/j.jembe.2013.02.007mailto:[email protected]://www.cephalopodresearch.org/http://dx.doi.org/10.1016/j.jembe.2013.02.007http://-/?-http://-/?-


2/9

identied, the rst being a noticeable lighting of chromatophore

patterns due to infection. Skin appears to be wrinkled,showing hyper-

plasia of the epidermisand increased mucus production. Gram negative

bacteriaVibrio alginolyticus, Vibrio damsela, Pseudomonas stutzeri, and

Aeromonas caviae were isolated from O. joubini ulcers; while Vibrio

parahaemolyticus, V.damsela, and P.stutzeri where isolated from the ul-

cers ofO.briareus(Hanlon et al., 1984).

Ford et al. (1986) found bacteria as natural populationson the mantle

of wild-caughtLolliguncula brevis in the absence of evident damages tothe host. In addition, it appears that wild squids have less bacterial popu-

lation than those reared in tanks. The bacteria recorded on wild squids

were mostly the Gram negative:Aeromonas sp.,Flavobacteriumsp.,Pseu-

domonas sp., Proteus sp., V.parahaemolyticus, V. alginolyticus, Vibrio sp. and

Flexibacter. All of these were also found on the normal skin of squid reared

in tanks. However, V. alginolyticus, Vibrio metschnikovii, Aeromonas sp.,

andPseudomonas sp. were the only ones noticed on ulcerated skin of

squids.Bacillussp. andStreptococcussp. were found in wild squids and

also in those kept in laboratory both in conditions where the animals

appeared with and without ulcerations (Ford et al., 1986).

Mantle and arms are not the only parts of the body of cephalopods

susceptible to bacterial infection. The gills are in contact with the envi-

ronment all the time and therefore exposed to numerous pathogenic

agents. For example, the gills ofO. vulgaris have been found infected

by Rickettsiales-like organisms. These are observed like basophilic

intracytoplasmatic microcolonies (about 102m long) appearing with-

in epithelialcellsof the gills.Gill cells becamehypertrophic andnecrosis

was occasionally observed. No signicant harm has been observed in

the host, but bacteria are able to have a detrimental effect on the respi-

ratory gaseous exchange of the octopus (Gestal et al., 2008).

One of the most recent records of bacterial infections in wild ceph-

alopods, was reported inO.vulgariskept in oating cages at the Ria of

Vigo (Farto et al., 2003). The specimens show lesions in the mantle

and some of them died once in laboratory. Lesions on the mantle

have been attributed to the bacteriaCytophaga-like andPseudomonas,

which were isolated from the damaged tissue. However, the Gram

negative bacteria Vibrio lentus, originally isolated from reared

Mediterranean oysters (Macan et al., 2001), was isolated for

the rst time from the branchial heart of octopuses. Experimental infec-tions performed by a challenge bath ofV. lentus (72 h, 2108 cfu/ml) in-

duced mortalityin 50%of octopusesaftertherst6 h. Thelesion showed

a typical round pattern in the arms or the head. No variations in mortal-

ity rate were recorded after 9 h post-infection, which is assumed to be a

result of inter-individual differences in the immune system (Farto et al.,

2003). Lowsalinity(29%)reportedin thearea wassuggested be a stress-

or that may impair immune response of animals against the opportunis-

tic pathogenV.lentus(Farto et al., 2003; Ford et al., 1986).

2.2. Protozoa: the eimeriorin coccidia Aggregata spp.

Coccidians of the genus Aggregataare a source of a severe disease

in cephalopods. The protozoan infects the digestive tract of the host(Hochberg, 1990), mainly the caecum, thus impairing the absorption

of nutrients (Boucher-Rodoni et al., 1987).

The genusAggregatais distributed all around the world. A total of

10 species have been described to date (Gestal et al., 2010) infecting

cuttleshes, squids and octopuses and also octopuses inhabiting

deep-sea hydrothermal vents (Table 1).

Traditional identication and characterization ofAggregataspecies

have relied primarily on differences in morphological features such as

size and shape of sporogonial stages and host specicity. Nowadays,

molecular techniques provide useful methods for taxonomic studies,

and are important tools in solving problems of species delimitation.

So far, molecular characterization ofA . octopiana and A. eberthi has

been carried out by sequencing the 18S rRNA gene (Kopecn et al.,

2006; Gestal,pers.comm.).

The intracellular protozoan Aggregataspp. has a heteroxenous life

cycle which requires a crustacean intermediate host to develop its

merogonic stage, while cephalopods are the denitive hosts in which

the parasite develops gamogony and sporogony stages (Hochberg,

1990). The infection byAggregataspp. has been recorded being almost

exclusive of O. vulgaris and Sepia ofcinalis in Spain (Pascual et al.,

1996a) reaching about 82106 sporocyst per gram of infected tissue.

Taking in consideration the elevated infection prevalence and intensity,

and the important pathological effects, parasites of the genusAggregata

are known to be the main epizootiological agents in wild and cultured

octopus stocks (Gestal et al., 2007b).

Infections byAggregatainitiate in the mucosal folds where the tis-

sue ruptures at the basal membrane and detachment of the epithelial

cells is produced. As a consequence, the mucosal folds of the intestine

and caecum suffer atrophy; at the intracellular level, displacement of

the nucleus host cell to one side is visible (Gestal et al., 2002a;

Poynton et al., 1992). All the infected tissues show hemocytic inltra-

tion and a pericyst reaction in both (gamogony and sporogony) infec-

tive stages (Gestal et al., 2002a; Licciardo et al., 2005; Mladineo and

Jozic, 2005). The capsule formed is originally composed ofattened

hemocytes and then connective tissue elements appear (Tripp,

1974). In senescent octopuses, the infection is predominated by

sporogonial (few merogonial) stages that extend widely in the tissue,

showing scarce hemocyte inltration or brotic reactions, signs of a

weak immune system (Pascual et al., 2010). During severe infectiveepisodes the pathology is even extended to the mantle and gill's con-

nective and epithelial tissues with similar signs of damage (Mladineo

and Bocina, 2007).

The injury caused by the protozoan also has an effect at a biochem-

ical level. The infection produces decrease of thepH of the digestive tis-

sue infected, and as a consequence an inaccurate functioning of the

digestive enzymes, such as maltase and leucin-aminopeptidase, thus

producing a malabsorption syndrome (Gestal et al., 2002b). In addition,

heavily infected specimens show poor conditions reected in Fulton's

condition index, low DNA/RNA ratio, RNA/protein conversion and

even decrease of the number of circulating hemocytes (Gestal et al.,

2007b).

Although pathologies induced by this protozoan are not fatal, it se-

verely weakens the cephalopod host making it more vulnerable toother biotic and abiotic stressors (Pascual et al., 2007).

The case of chronic infection by the coccidia Aggregataspp. in the

cephalopod host offers the opportunity to study the mechanisms of im-

mune response of the cephalopods at different developmental stages of

thehost lifecycle, and different intensities of infection.Then,this should

be established like a model study of the hostparasite relationship.

2.3. Metazoa

Since the review written byHochberg (1990),the research added

in the last years has contributed to increase the knowledge on the

biology of cephalopods, their trophic relationships (Gonzlez et al.,

2003) and the importance of parasites as marine tags ( Pascual and

Table 1

A tabularized overview ofAggregataspecies reported to infect cephalopods.

Cephalopod host Species of Aggregata References

Sepia ofcinalis A.eberthi Dobell (1925)

Todarodes sagittatus A.sagittata Gestal et al. (2000)

Martialia hyadesi A.andresi Gestal et al. (2005)

Octopus vulgaris A.octopiana Gestal et al. (1999b)

Octopus bimaculoides A.millerorum Poynton et al. (1992)

Octopus doeini A.dobelli Poynton et al. (1992)

Octopus tehuelchus A.valdessensis Sardella et al. (2000)Enteroctopus megalocyathus A.patagonica Sardella et al. (2000)

Vulcanoctopus hydrothermalis A.bathytherma Gestal et al. (2010)

15S. Castellanos-Martnez, C. Gestal / Journal of Experimental Marine Biology and Ecology 447 (2013) 1422


3/9

Hochberg, 1996) to resolve cephalopod migrations (Semmens et al.,

2007).

Cephalopods are secondary, third or paratenic hosts for trema-

todes digenea, cestodes and nematodes (Hochberg, 1990). According

to the ecological and behavioral features of the cephalopod's life

cycle, they occupy an ecological niche that makes them favorable to

be infected by specic groups of parasites. Those parasites are trans-

mitted to the denitive host: shes, marine mammals or birds

(Clarke, 1996; Gonzalez et al., 2003).

2.4. Cestoda

Among the cestodes carried by cephalopods, plerocercoids of

Phyllobothrium sp. and Pelichnibothrium speciosum, Tentacularia

coryphaenae, and Hepatoxylon trichiuri infect the digestive tract of

Dosidicus gigas from the central East Pacic and Chile (Pardo-

Gandarillas et al., 2009; Shukhgalter and Nigmatullin, 2001). In addi-

tion, new data has also shown the presence of those plerocercoids in

Illex argentinusfrom the Atlantic (Nigmatullin and Shukhgalter, 1990;

Sardella et al., 1990), and inIllex coindetii from the Adriatic Sea (Petric

et al., 2011). In Spain, the plerocercoid cestodes Dinobothrium sp.,

Nybelinia yamagutii, and Nybelinia lingualis have been identied in

the ommastrephid squids I. coindetii and Todaropsis eblanae(Pascualet al., 1996b), and also in Todarodes sagittatus, O. vulgaris, Loligo

vulgaris,Sepia orbignyanaandEledone cirrhosa(Pascual et al., 1996a).

2.5. Trematoda

Little research has been done in digenetic trematodes since

Overstreet and Hochberg (1975) and Hochberg (1990). Most of the

newrecords belongto unidentied Didimozoidae metacercaria infecting

the digestive tract ofD. gigas from the NW Pacic(Nigmatullin et al.,

2009; Shukhgalter and Nigmatullin, 2001). The intensity of infection is

variable, from one to even 1500 larvae (Nigmatullin et al., 2009), and

prevalence has been reported to be up to 86% in squids with mantle

length (ML) ranging 30431 mm (Nigmatullin et al., 2009; Shukhgalter

and Nigmatullin, 2001).The species Derogenes varicus and Hirudinella ventricosa were identi-

ed from the digestive tract of I. argentinus by Nigmatullin and

Shukhgalter (1990), and metacercaria of didymozoidMonilicaecumsp.

have been recorded in I. argentinusparalarvae from Brazil (Vidal and

Haimovici, 1999). However, the infection through an intermediate

host in paralarvae smaller than 3.7 mm ML was discarded, because

crustacean prey has not been recorded in paralarvae's digestive tract

(Vidal and Haimovici, 1998). In contrast, large paralarvae could be

infected by an intermediate host such as copepods (Vidal and

Haimovici, 1999).

The identication of larval stages of helminthes is difcult because

they do not show adult features. As a consequence, they are usually

recorded only as genera, except some Trypanorhynchacestodes that

can be recognized because the tentacular armature (Randhawa,2011). Therefore, molecular tools are used in order to identify larval

stages and to complement morphological descriptions with molecu-

lar characterization based on the large subunit ribosomal DNA

(Agust et al., 2005; Randhawa, 2011). Digenetic parasite species are

usually distinguished based on the sequences of internal transcribed

ribosomal spacer regions (ITS), which are well conserved and useful

for determining species boundaries (Nolan and Cribb, 2005).

2.6. Nematoda

Nematode parasites use marine mammals as denitive hosts as

well as birds that feed on infected sh, whereas crustaceans are the

rst intermediate hosts, and cephalopods, mainly squids, play a role

of intermediate or paratenic hosts (Mattiucci and Nascetti, 2008).

Humans are accidental hosts, and when infected they can manifest

allergies and digestive disorders (Audicana et al., 2002).

As before, only larval stages occur in cephalopods; therefore, an

accurate taxonomic identication is unavailable since adult features

areneeded (Hochberg, 1990). Furthermore, theexistence of sibling spe-

cies makes essential genetic identication by sequencing genomic DNA,

ITS regions or mitochondrial DNA (Mattiucci and Nascetti, 2008).

Nematodes are certainly widespread commonly inside a connective

tissue capsule mainly infecting the digestive tract, but they can also befound in the gonads (Pascual et al., 2007). Records fromOmmastrephes

bartramiiandD.gigasfrom the southeastern Pacic include nematode

speciesAnisakis physeteris, Prorrocaecum sp., Contracaecum, andAnisakis

types I and II, distinguished by the presenceabsence of mucron and tail

shape (Nigmatullin et al., 2009; Pardo-Gandarillas et al., 2009). From

Galician waters,Anisakis simplex s. str. hasbeen recorded in thecuttlesh

S. ofcinalis, Sepia elegans and squids Allotheuthis subulata, T. eblanae,

I. coindetii and T. sagittatus (Abollo et al., 2001; Pascual et al., 1999).

The highest prevalence ofAnisakislarvae was harbored by T.sagittatus

(34%) and T. eblanae, which were also found in the sh Merluccius

merluccius, Prionace glauca, Lophius piscatorius, Belone belone and

Scorpaena scrofa(Abollo et al., 2001).I.coindetiiis infected by Anisakis

peggrefi in the Adriatic Sea (Petric et al., 2011) and byA.simplexand

Hysterothylaciumsp. in the Tyrrenhian Sea (Gestal et al., 1999a).

The numerous nematode records in cephalopods usually register

the taxonomic identity and site of infection. However, the tissue

host reaction is scarcely mentioned, which could be due to the ab-

sence of gross pathology associated to the parasites that are encysted

in a capsule of connective tissue mainly in the stomach, gonads and

nidamental glands (Abollo et al., 1998). The histological inspection

of infected organs exposes displacement of host tissue in direct con-

tact with the nematode larvae. A variable inammatory reaction is

visible by the hemocytes that move towards the place of infection,

and in addition, secretion of mucus and cell debris is clearly observed

(Abollo et al., 1998; Pascual et al., 1995).

2.7. Crustacea

Crustaceans are macroparasites that mainly inhabit the mantle cav-ity and the gills of cephalopods, although they can also be found over

external surfaces of the body such as arms or head ( Hochberg, 1990).

The mantle cavity and gills are suitable sites for harboring the cope-

podPennella such as in I. coindetii, L . vulgaris, A. subulata, Alloteuthis

mediaor the octopodE.cirrhosa(Gestal et al., 1999a). Post-embryonic

stages of Pennella have a seasonal infestation pattern with a peak

in winter and spring. In addition, parasites are visibly aggregated in

I. coindetii perhaps due to reproductive reasons (Pascual et al., 2001).

Post-embryonic stages ofPennellasp. do not have a negative effect on

the cephalopod growth, but affect specimens heavily infected (Pascual

et al., 1997). Infections ofPennellasp. have been reported to affect the

condition of O. vulgaris, E. cirrhosa and S. ofcinalis (Pascual et al.,

1996a). The common octopus,O.vulgaris, is also infected by the cope-

podOctopicolasp., the squidI.coindetiiharborStellicola hochbergi, andDoridicolacf. agiliswas found in the squid T. sagittatus(Pascual et al.,

1996a).

Few isopods are also hosted in the mantle cavity of cephalopods

(Hochberg, 1990), but they are assumed as accidental or temporary

infections (Pascual et al., 2002). The cymothoid isopods mainly in-

habit the gill chambers, skin and sh ns (Hochberg, 1990). In addi-

tion, Bello and Mariniello (1998) provided the rst record of the

cymothoid isopod Livoneca sinuata found in the mantle cavity of

Sepiola ligulatafrom the Adriatic Sea.

Cymothoids establish unusual associations with jellysh, crusta-

ceans and other organisms, although this association seems to be fre-

quent with cephalopods. Therefore, the nding of several specimens

ofL. sinuatain the mantle cavity ofL. vulgaris from Turkey cannot be

considered rare (Trilles and Oktener, 2004). The gills of this squid host

16 S. Castellanos-Martnez, C. Gestal / Journal of Experimental Marine Biology and Ecology 447 (2013) 1422


4/9

were found infected by the isopod Anilocra physodes, although the par-

asite probably was acquired during trawl nets (Gestal et al., 1999a).

Cryptoniscus larvae of Epicaridea isopods were found embedded as

minute opaque external marks (surrounded by a membrane) at the

beginning of the esophagus inLoligo gahi. Due to the location of the

parasite, it probably does not obstruct the feeding activity, but it

could destroy the musculature and as a consequence, affect mastica-

tion (Pascual et al., 2002).

3. Most common endosymbionts

3.1. Bacteria, Vibrio scheri

A special case is the association between the Hawaiian Bobtail

Squid Euprymna scolopes and the bacteria V. scheri, a symbiosis

that initiate as soon as the squid hatches (McFall-Ngai, 1994). The

bacteria enter into the light organ of the animal and packed tightly

in the crypts. Once the symbiosis is established, the bacteria start to

emit light, and as a consequence the squid looks luminescent on its

ventral side, thus matching downwelling moonlight and/or starlight,

as a strategy to avoid predators (Nyholm and McFall-Ngai, 2004).

Theimmune systemofE. scolopes is educated to let the colonization

only by V.scheri. Inside the squid's light organ, the peptidoglycan of

V. scheri and environmental bacteria stimulates mucus secretion

from the supercial ciliated epithelia,but only alive Gram-negativebac-

teria aggregates tightly within the mucus matrix; the outer membrane

proteins ofV. scheri prevent adhesion by host hemocytes and evade

phagocytic response (Nyholm et al., 2009). In addition,V.scheri pro-

motes irreversible apoptosis of ciliated epithelial cells in the crypts. Fur-

thermore, ducts are constricted to discourage further colonization by

environmental symbionts, and the cell cytotoxic response is attenuated

as part of the symbiotic role played by V. scheri (Altura et al., 2011;

McFall-Ngai et al., 2010).

3.2. Dicyemida (Mesozoa)

Dicyemids are endosymbionts that inhabit the renal sacs of ben-

thic cephalopods (octopuses and cuttleshes, Hochberg, 1990), butalso the squid Todarodes pacicus (Furuya and Tsuneki, 2003) and

branchial heart appendages ofRossia pacica(Furuya et al., 2004b).

Typically vermiforms, they have a low number of cells (840) and

lack of organs and cavities (Furuya and Tsuneki, 2003). The name

Dicyemida refers to the two stages in their life cycle: nematogen,

characterized by asexuate reproduction, and rhombogen (sexuate,

Hochberg, 1990). The zygote develops into an infusoriform embryo

which is released into the host urine at the end of its development;

therefore, it is expelled towards the sea (Furuya and Tsuneki, 2003).

Presumably, an elevated density of dicyemid population stimu-

lates the shift between asexual and sexual reproduction; alternatively

this shift may be linked to the reproductive status of the host. A bio-

chemical message is suggested to signal to the dicyemids the onset of

the reproductive phase in the cephalopod host (Hochberg, 1990).This let vermiforms to reproduce before the cephalopod host dies.

Vermiform stages are composed by a central long cell, the axial cell,

enveloped by a single layer of ciliated cells (McConnaughey, 1983). The

anterior part, thecalotte, is composed by 410 cells whichare important

for taxonomic identication (Furuya and Tsuneki, 2003; Hochberg,

1990). The shape of the calotte is different among species, presumably

as an adaptation to attach to specic zones inside the renal sacs

(Furuya and Tsuneki, 2003). In contrast, infusoriform embryos are mor-

phologically complex, and they are typically composed by 3739 cells,

which are species specic (Furuya et al., 2004a). Renal sacs provide

space and food for the maintenance of dicyemids. These attach their ca-

lotte into the crypts of therenal sacs, while therest of the bodyoats in

the host urine to take nutrients through the ciliated cells along the body

via endocytosis (Hochberg, 1990).

Despite the fact that dicyemids are commonly found in cephalo-

pods, it is not clear if dicyemids damage the host. Apparently, no

damage is produced by dicyemids; it has been supposed that they

contribute to eliminate ammonium from the host urine (Hochberg,

1990). However, dicyemids could be a problem when the population

rises so much that it blocks the renal sac ducts. On the basis of these

considerations dicyemids are considered endosimbyonts (Furuya

and Tsuneki, 2003; Hochberg, 1990).

Dicyemid have been reported from a variety of hosts and sites, suchas Australia (Finn et al., 2005), the Atlantic and the Mediterranean Sea

(Gestal et al., 1997), Mexico (Castellanos-Martinez et al., 2011), and

principally from Japan (Furuya, 2008, 2009, 2010).

Whether dicyemids are primitive animals or not is still debated.

They present tubular cristae, a double-stranded ciliary necklace and

lack of collagenous connective tissue; on the basis of these characteris-

tics, dicyemids were classied as Protozoa by Cavalier-Smith (1993)

arguing that multicellularity is not a conclusive feature to classify

them in Animalia. Therefore, dicyemids were classied as multicellular

protozoa. On the other hand, Furuya et al. (1997)demonstrated the

presenceof two types of cellular junctions(adherent and gap junctions)

in vermiforms and infusoriform embryos, which is a feature absent in

colonial organisms. Hence, although dicyemids have no tissues, they

present basic types of cell junctions similar to multicellular animals,

and therefore, dicyemids should not be considered as primitive organ-

isms (Furuya et al., 1997).

The basic morphology of dicyemids has been assumed to be de-

rived from the endosymbiotic life style (Stunkard, 1954). Data de-

duced from several studies including 18S and DoxC (Kobayashi

et al., 1999, 2009), serotonin (putatively involved in the functioning

of cilia and developmental processes: Czaker, 2006), Pax6 (Aruga

et al., 2007) and innexin (Suzuki et al., 2010), conrm the view that

dicyemids are simplied Bilateria derived from a triploblastic ancestor,

belonging to Lophotrochozoans but not related to platyhelminthes

(Suzuki et al., 2010).

4. Response to diseases: overview on the cephalopod

immune system

Cephalopods are advanced mollusks with a well developed circu-

latory system; a systemic and two accessory hearts (branchial hearts)

distribute the hemolymph through arteries and capillaries to the

whole body (Schipp, 1987; Wells and Smith, 1987). Branchial hearts

contribute to the production of hemocyanin, and elimination of parti-

cles (Beuerlein et al., 1998, 2002). Similar to other mollusks, cephalo-

pods have a non adaptive (or innate) immune system. They do not

have immunoglobulins and therefore they do not have extended pro-

tection against pathogens for future infections. Thus, the cephalopod

immune system works on the basis of cellular factors. The hemo-

cytes respond by phagocytosis, encapsulation, inltration or cytotoxic

activities to infections and destroy or isolate pathogens. In addition,

molecules dissolved in the serum (opsonins, agglutinins, lysozyme)

also contribute to the immune response (Ford, 1992).

4.1. Cellular elements and their role

The hemocytes play a major role in the internal defense, by the

recognition and the elimination of foreign materials, as well as shell

and wound repair (Cheng, 1975). In cephalopods the hemocytes

(also named leukocytes), are produced in the white bodies located

behind the eyes in the orbital pits of the cranial cartilages ( Cowden,

1972). A white body is constituted by two primary lobes, of unequal

size, organized into several secondary lobes and a large number of

small lobules providing a glandular appearance to the organ (Claes,

1996). Its embryonic development has not been studied yet

(Cowden and Curtis, 1973). Inside the organ, strings of leukopoietic

cells are found in different developmental stages (Cowden, 1972).



5/9

Their leukopoietic function is deduced from the ultrastructural simi-

larities between the putative nal stage of their cells and the circulat-

ing blood cells, which correspond to a single cell line; hence, only one

type of hemocyte is found in the peripheral hemolymph (Claes, 1996;

Cowden and Curtis, 1973, 1981).

At least two kinds of hemocytes have been identied in bivalves and

gastropods(hyalinocytes and granulocytes)according to the presenceor

absence of granules, which are characterized by staining afnity (Chu,

2000; Lpez et al., 1997; Salimi et al., 2009). Furthermore, there is anagreement about the function of hemocytes to repair tissue damage,

nutrient transport and digestion, and internal defense against non-self

material (Cheng, 1975; Chu, 2000). However, in thecase of cephalopods,

those tasks are performed by the single type of cell present in the circu-

lating hemolymph (Claes, 1996; Cowden and Curtis, 1981).

Wound repair involves the movement and aggregation of hemo-

cytes at the injured site to prevent bleeding, until epithelial cells

grow over the wound to complete the healing (Chu, 2000). In cepha-

lopods hemocytes are capable to form a plug which is accompanied

by vasoconstriction and collagen synthesis to help to repair a lesion

(Ferl, 1988).Pascual et al. (2006)reported the nding of specimens

ofOctopus hubbsorum with a large knob on the dorsal mantle and

nodules with smooth surface on the sucker's base. The histological

analysis showed a mass proliferation of dense brous tissue between

the dermis and muscle layers suggesting that the tissue has been

repaired by the hemocytes (Chu, 2000). Because the knob is located

in the area where octopuses are usually hooked, the authors showed

the capability of the hemocytes to restore the tissue injured in octo-

puses that escaped from shermen catches.

As in their molluskan relatives (Lpez et al., 1997) the cellular de-

fense by cephalopod hemocytes involves phagocytosis as well as pro-

duction of oxygen and nitrogen radicals (Ford, 1992; Malham and

Runham, 1998; Malham et al., 1997; Rodrguez-Domnguez et al.,

2006). Phagocytosis of microbial agents and non-self materials is an im-

portant defense reaction (Cheng, 1975; Chu, 2000). In addition, a low

number of circulating cells can be a sign of stress (Malham et al.,

1998). Changes in the number, morphology or viability of hemocytes

can be used as an indicator of the organism's health (Ellis et al., 2011)

since variations have been found in relation to parasitic infections ( daSilva et al., 2008) or contamination (Mayrand et al., 2005).

Malham et al. (1997) recorded 80% of phagocytic hemocytes in

E. cirrhosa when challenged with not opsonized Vibrio anguillarum.

Longest exposure to the bacteria led to a higher percentageof phagocyto-

sis, mainly if the bacteria were pre-incubated in cephalopod hemolymph

free of cells, which suggests that phagocytosis is assisted by opsonizing

elements (Malham et al., 1997). However,Rodrguez-Domnguez et al.

(2006)recorded 50% of phagocytosis in hemocytes ofO.vulgarischal-

lenged with zymosan (not opsonized). In addition, phagocytosis did

not increase with the incubation time (Rodrguez-Domnguez et al.,

2006). A similar result was recorded by ow cytometry after chal-

lenging O . vulgaris hemocytes with uorospheres (maximum level

of phagocytosis=55%, Castellanos-Martinez and Gestal, 2011). In

both cases, the incubation was performed at 15 C.Microorganisms also trigger the phagocytic reaction. However,

this is not effective when biotic and/or abiotic particles are larger

than hemocytes. Under such circumstances hemocytes surround the

particle forming various layers of cells, isolating it and limiting poten-

tial damage (Chu, 2000), even the defensive response is not capable

to eliminate the intruder (Tripp, 1963). This is commonly found in

cephalopods infected by helminthes and nematodes, due to their

large size (even when in larval forms).

4.2. Citotoxicity

4.2.1. Reactive oxygen intermediates (ROIs)

Destruction of pathogens through phagocytosis or under hemocyte

stimulation is complemented with the production of oxidative

chemicals. Most frequently, these are represented by reactive oxygen

intermediates (ROIs), collectively known as respiratory burst. In these

conditions, an increased uptake and consumption of oxygen and stimu-

lationof NADPH oxidaseoccurs (Chu, 2000). Theinitial metabolite is su-

peroxide anion (O2), which is dismutated to hydrogen peroxide

(H2O2), and converted to other toxic ROIs such as hydroxyl radical

(OH) and singleoxygen 1O2 (Bugg et al., 2007). ROIs areusually mea-

sured in the cellular fraction; this allows investigating any change in

hemocyte functionality mediated by bactericidal or pathogen activity(Ellis et al., 2011). The most common assays utilized to measure ROIs

are based on nitroblue tetrazolium (NBT) reduction and luminol-

dependent chemiluminiscence (LDCL). In the rst case, oxygen radicals

(O2) can reduce yellow, water soluble, NBT to an insoluble dark

blue formazan visible under microscope or spectrophotometer after

extracting formazan from the cells (Anderson, 1994; Pipe, 1992). LDCL

is utilized to measure the activity of myeloperoxidase/hydrogen perox-

ide (MPO/H2O2) system; luminol generates excited aminophthalate

anions that relax to the ground state with the production of light

(Anderson, 1994).

Radicals are released into the extracellular medium to kill patho-

genic agents. ROI production is a common defense mechanism no-

ticed in bivalves as Mytilus edulis (Pipe, 1992), Crassosstrea virginica

(Anderson, 1994), Mytilus galloprovincialis (Arumugam et al., 2000)

andMercenaria mercenaria (Bugg et al., 2007). Few records are avail-

able for cephalopods.Malham et al. (2002)showed that hemocytes of

E.cirrhosaproduce intracellular superoxide in response to stress. The

superoxide production increases after octopus exposure to the air for

5 min, indicating that this radical is produced by the animal also in

response to this kind of stress (Malham et al., 2002). By applying

the reduction of ferricytochrome C, Novoa et al. (2002) measured

the production of superoxide after stimulation of the circulating he-

mocytes and white body cells withEscherichia colilipopolysaccharide

(LPS), zymosan and PMA. The response was obtained in the white

bodies and by circulating hemocytes using PMA and LPS, but the

highest reaction was recorded when stimulated with zymosan

(Novoa et al., 2002).

Currently,ow cytometry is a widely used tool to measure molluskan

hemocyte immune response through the detection ofuorescence pro-duced by each cell (Bugg et al., 2007). Flow cytometry is advantageous

since it allows almost real-time measurement of the response and to an-

alyze the response of each cell within a big sample (Davey, 2002). The

oxidative activity measured in O. vulgaris hemocytes after challenging

the cells with zymosan showed that the uorescence produced by the

hemocytes varied from 111.6% to 129.5% (Castellanos-Martinez and

Gestal, 2011).

Since oxidative activity is activated in response to pathogens, it is

reasonable to expect that parasites affecting cephalopods use strate-

gies to deactivate the hemocyte cytotoxic response. A recent study re-

vealed that ROIs decrease inO.vulgarishemocytes when the infection

by the protozoan A. octopiana increases (Castellanos-Martinez and

Gestal, 2011).

4.2.2. Nitric oxide

Nitric oxide (NO) is considered part of the innate immune response

and is synthesized after parasite infection (Rivero, 2006). NO results

from the oxidation of L-arginine to citrulline by the enzyme nitric

oxide synthase (NOS) which is present in mammals as neuronal, induc-

ible and endothelial isoforms. NO is a signaling molecule with a physio-

logical function in vasodilatation, secretor control, intestinal relaxation,

macrophage cytotoxicity, regulation of developmental processes, neu-

rotransmission and neuromodulation (Jacklet, 1997; Palumbo, 2005).

Furthermore, NO has been detected in the central nervous system of

Polyplacophora, gastropods and cephalopods (Palumbo, 2005). Inceph-

alopods, nitricoxidesynthase hasbeen suggestedto play a role in tactile

learning (Robertson et al., 1994); the presence of NOS in the brain ofS.



6/9

ofcinalis let to hypothesize the role of NO as a messenger molecule

(Di Cosmo et al., 2000; Di Cristo et al., 2007).

NO is a highly-reactive free radical gas that is not stored and readily

diffuses through membranes (Jacklet, 1997), so it is an effective agent

against pathogens. A reduction of NO was observed in erythrocytes

infected with Leishmania donovani in contrast to control cells

(Chowdhury et al., 2010). Similarly, NO produced byO.vulgarishemo-

cytes seems to decrease with the increase of infection by A.octopiana.

A special case is the symbiotic relationship between the squidE.scolopesand the bacteria V.scheri (see above). This relationship is

so intimate that biochemical communication avoids possible attacks

by cytotoxicity of cells (McFall-Ngai et al., 2010). NOShas been detected

in the cells lining the ducts and antechambers of the crypts of the light

organ including in the mucus; a weak level has been observed in the

deep crypts and in ciliated epithelial tissue (Davidson et al., 2004).

Apparently NO works by limiting the aggregating population of

V.schericells, inducing the bacteria to turn on genes related to resis-

tance to NO (McFall-Ngai et al., 2010). In fact, NOS and NO, are attenu-

ated in the symbiotic areas of the light organ as early as 6 h after

colonization, and this level appears irreversible when the symbiosis is

completely established (Davidson et al., 2004). Moreover, NO attenua-

tion seems to be required to induce apoptosis in ciliated epithelial

cells, a strategy that prevents colonization by environmental bacteria

(Altura et al., 2011; Nyholm and McFall-Ngai, 2004). Attenuation of

NO perhaps occurs through the activation ofV.scheri hnoXgene that

encodes for a heme NO/oxygen-binding (H-NOX) protein. H-NOX be-

longs to a family of putative sensor proteins present in bacteria, thus

V.schericould use it for facilitating colonization (Wang et al., 2010).

4.3. Humoral factors

Marine mollusks lack specic immune response and immunoglobu-

lins; instead factors with agglutinating, opsonic, lytic, antimicrobial and

protease-inhibition activitiesare present in the serum.Those factors are

part of the mollusk humoral defense (Chu, 2000). Humoral factors com-

plement the cellular activity. After the internalization of a particle or

pathogen, this is enclosed in a vacuole (phagosome) where killing and

destruction takes place by toxic radicals (oxygen or nitrogen) or en-zymes like acid phosphatase, peroxidase, -glucuronidase, NADH oxi-

dase and lysozyme (Cheng, 1975; Chu, 2000).

The cephalopod cell-free hemolymph is the carrier of oxygen,

which is delivered to the whole organism (Wells and Smith, 1987),

but it is also the carrier of the humoral components that include

lectins, such as the 260-kDa lectin described in O. vulgaris (Rgener

et al., 1985). Recently, Alpuche et al. (2010) described a lectin of

66 kDa (OmA) found inOctopus mayawhich was not been identied

before. It was found to be a homolog to the type A hemocyanin from

Octopus doeini. Due to the specicity of the lectin to galactosamine,

mannose and fucose, it was suggested that it could play a role in the

immune response by recognizing and agglutinate oligosaccharides

from cells and perhaps also from pathogens (Alpuche et al., 2010). In

the presence of rat erythrocytes the hemagglutinating activity of thenew OmA lectin from O . maya was elevated (Alpuche et al., 2010).

Antibactericidal activity of sera from O . maya was conrmed using

beef erythrocytes, but sera from S. ofcinalis and Sepioteuthis

lessoniana resulted to have higher agglutinating success over a wide

range of bacteria (Fisher and Dinuzzo, 1991).

Enzymes like lysozyme are part of the defense mechanism. Its ef-

fectiveness against a broad variety of bacteria is due to the catalyzed

hydrolysis ofN-acetylmuramic acid (14)N-acetylglucosamine links

of the polymeric chains in the bacterial cell wall. Lysozyme is highly

concentrated in leukocytes, neutrophilic granulocytes and macro-

phages (Grossowicz et al., 1979), but the enzyme has also been

found inthe serum ofC. virginica (McDade andTripp, 1967) and inhe-

mocytes and tissue from the octopusE.cirrhosa (Malham et al., 1998).

The lysozyme activity was higher in hemocytes of octopuses infected

by V. anguillarumwhen measuredimmediately afterinjection; activity

that was reduced after 4 and 24 h (Malham et al., 1998).

5. Genomic approach: molecular tools and gene expression

technologies applied to pathogens to cephalopod hosts

For many pathogens of cephalopod mollusks, current diagnostic

techniques are rather limited, and screening has been restricted to his-

tological and ultrastructural examination. Protozoans and anisakids arethe most studied cephalopodpathogens. Most recently, molecular tech-

niques for detecting and identifying pathogens in cephalopods have

been developed as valid and suitable tools. They are expected to be in-

creasingly utilized in pathogen monitoring programs.

However, the routine use of DNA-based diagnostic tools is hampered

by a number of major concerns. Not all regions of the pathogen DNA are

equally useful as targets for molecular detection. It is necessary to identify

regions of the genome that may prove useful for species differentiation. In

addition, molecular techniques could be useful to determine if strains

demonstrate genetic and/or virulence differences (Gestal et al., 2008).

To date, most of the studies involved in the research of the host

immune system are devoted to understanding how the immune sys-

tem responds against pathogens beyond the functional response. Be-

cause mollusks lack of adaptive immune response they can only face

pathogens with their innate immunity, being the hemocytes the main

effectors (Cheng, 1975).

Expressed sequence tags (ESTs) have been sequenced from redun-

dant, normalized libraries and are currently used as a valuable molecu-

lar tool. They have been successfully applied to nd genes which are

involved in different physiological processes (e.g. respiratory chain,

cell communication, cell defense). ESTs havealso been successful to de-

terminate genes differentially expressed, mainly in bivalves of aquacul-

ture interest naturally infected by parasites such as Ruditapes decussatus

infected by Perkinsus olseni (Prado-Alvarez et al., 2009) or in those

experimentally challenged with bacteria such as R.decussatus(Gestal

et al., 2007a) or M. galloprovincialis (Li et al., 2010; Pallavicini et al.,

2008). Although cephalopods are important subjects in aquaculture

practice (Vaz-Pires et al.,2004), they are currently reared in the Atlantic

Galician coast inoating cages (Garca Garca et al.,2004),thereis still alack of knowledge about the molecular bases that regulate the cephalo-

pod immune response.

Molecular tools have been successfully applied to study the sym-

biotic relationship betweenE. scolopesand the bacteriaV.schery. In

recent years 11 cDNA libraries were generated from light organs of

a pool of juvenile squids E. scolopeswith and without the colonizing

bacteriaV. scheri. From a total of 13,962 non-redundant ESTs 9,728

had a signicant hit to a protein in the NCBI nonredundant protein

database. From these, 6061 correspond to annotated ESTs; 2793 to

hypotetical and 874 to unknown proteins (Chun et al., 2006).

The data available from the cDNA library has lead to identify genes

related to the immune system such as the complement factor C3 in

tissues (light organ without core, central core, mantle, arm muscle,

gills and white body) of juvenile and adult squids. The lowest levelof C3 transcript was detected in arm tissue and hemocytes even

when those cell are the primary site of synthesis (Castillo et al., 2009).

Transcripts encoding proteins in the Toll/NF-B pathway have been

also identied. The analysis showed only one Toll-Like Receptor (TLR)

that probably works as a global microbe receptor. The MyD88-like tran-

script has not been identied from E. scolopes EST database; it was iden-

tied in C. gigas encoding a protein that links the TLR with the IRAK

protein. This result suggests a similar Toll/NF-kB pathway present in

mollusks, but further investigation is required (Goodson et al., 2005).

6. Closing remarks

As summarized above, few data have been added over the last

20 years to theclassical knowledge available forcephalopodparasitology.



7/9

Most of the studies utilized parasites to characterize the ecology of

squid stocks leaving aside the effect of parasites on the stocks' health.

However, the increasing economic importance of cephalopods in

worldwide sheries and aquaculture raises the interest not only to de-

velop research on zoonotic pathogens, but also to decipher the host

parasite relationship as seen from the sideof the cephalopod immune

response.

Recent advancements in molecular biology allowed to explore, for

example, gene expression in relation with immune response to dis-eases or parasite infections in cephalopods. In all the above studies,

the identity of the transcripts was determined by matching the exper-

imental sequence to the genomic data. However, despite the fact that

several thousands of redundant nucleotide records are counted for

mollusks in GeneBank, and the economic value of many cephalopod

species and the relatively reduced costs of building full-genome se-

quences of organism programs, no cephalopod has been sequenced

until now; only oysters have been selected for genome sequencing

among bivalves (Hedgecock et al., 2005). A research effort is needed!

The availability of the full-genome sequence data would be of great

help in the identication of many important genes related to the im-

mune system and the response to diseases in cephalopods.

Acknowledgments

This work has been partly funded by a research grant from the

Galician Council Xunta de Galicia (10PXIB402116PR). Sheila Castellanos-

Martnez has been supported by a scholarship from CONACyT. [SS]

References

Abollo, E., Gestal, C., Lopez, A., Gonzlez, A.F., Guerra, A., Pascual, S., 1998. Squid astrophic bridges for parasite ow within marine ecosystems: the case ofAnisakissimplex(Nematoda: Anisakidae), or when the wrong way can be right. S. Afr. J.Mar. Sci. 20, 223232.

Abollo, E., Gestal, C., Pascual, S., 2001. Anisakisinfestation in marine sh and cephalo-pods from Galician waters: an updated perspective. Parasitol. Res. 87, 492499.

Agust, C., Aznar, F.J., Olson, P.D., Littlewood, D.T.J., Kostadinova, A., Raga, J.A., 2005.Morphological and molecular characterization of tetraphyllidean merocercoids(Platyhelminthes: Cestoda) of striped dolphins (Stenella coeruleoalba) from theWestern Mediterranean. Parasitology 130, 461474.

Alpuche, J., Pereyra, A., Mendoza-Hernandez, G., Agundis, C., Rosas, C., Zenteno, E.,2010. Purication and partial characterization of an agglutinin from Octopusmayaserum. Comp. Biochem. Physiol. B: Biochem. Mol. Biol. 156, 1 5.

Altura, M., Stabb, E., Goldman, W., Apicella, M., McFall-Ngai, M.J., 2011. Attenuation ofhost NO production by MAMPs potentiates development of the host in the squid-vibrio symbiosis. Cell. Microbiol. 13, 527537.

Anderson, R.S., 1994. Hemocyte-derived reactive oxygen intermediate production infour bivalve mollusks. Dev. Comp. Immunol. 18, 8996.

Aruga, J., Odaka, Y.S., Kamiya, A., Furuya, H., 2007. DicyemaPax6 and Zic: tool-kit genesin a highly simplied bilaterian. BMC Evol. Biol. 7.

Arumugam, M., Romestand, B., Torreilles, J., Roch, P., 2000. In vitro production of super-oxide and nitric oxide (as nitrite and nitrate) byMytilus galloprovincialishaemocytesuponincubationwith PMA or laminarin or during yeast phagocytosis.Eur. J. CellBiol.79, 513519.

Audicana, M.T., Ansotegui, I.J., de Corres, L.F., Kennedy, M.W., 2002. Anisakis simplex:dangerous dead and alive? Trends Parasitol. 18, 2025.

Balguerias, E., Quintero, M.E., Hernandez-Gonzalez, C.L., 2000. The origin of the Saharan

Bank cephalopod shery. ICES J. Mar. Sci. 57, 15

23.Bello, G., Mariniello, L., 1998. Occurrence ofLivoneca sinuata(Isopoda, Cymothoidae) in

the mantle cavity ofSepiola ligulata(Cephalopoda, Sepiolidae). Arch. Fish Mar. Res.46, 3742.

Beuerlein, K., Schimmelpfennig, R., Westermann, B., Ruth, P., Schipp, R., 1998.Cytobiological studies on hemocyanin metabolism in the branchial heart complexof the common cuttleshSepia ofcinalis(Cephalopoda, Dibranchiata). Cell TissueRes. 292, 587595.

Beuerlein, K., Lohr, S., Westermann, B., Ruth, P., Schipp, R., 2002. Components of thecellular defense and detoxication system of the common cuttlesh Sepiaofcinalis(Mollusca,Cephalopoda). Tissue Cell 34, 390396.

Boucher-Rodoni, R., Boucaud-Camou, E., Mangold, K., 1987. Feeding and digestion.Cephalopod Life Cycles. Academic Press London, London, pp. 85108.

Boyle, P., Rodhouse, P., 2005. Cephalopods: Ecology and Fisheries. Blackwell Science,Ames, Iowa, pp. 1452.

Bugg, D.A., Hegaret, H., Wikfors, G.H., Allam, B., 2007. Oxidative burst in hard clam(Mercenaria mercenaria) haemocytes. Fish Shellsh Immunol. 23, 188196.

Caddy, J.F., Rodhouse, P.G., 1998. Cephalopod and groundsh landings: evidence forecological change in global sheries? Rev. Fish Biol. Fish. 8, 431444.

Castellanos-Martinez, S., Gestal, C., 2011. Immune response ofOctopus vulgarisagainstthe infection by the gastrointestinal parasite Aggregata octopiana. J. Shellsh. Res.30, 997998.

Castellanos-Martinez, S., Carmen Gomez, M., Hochberg, F., Gestal, C., Furuya, H., 2011. Anew dicyemid from Octopus hubbsorum (Mollusca: Cephalopoda: Octopoda).

J. Parasitol. 97, 265269.Castillo, M.G., Goodson, M.S., McFall-Ngai, M.J., 2009. Identication and molecular

characterization of a complement C3 molecule in a lophotrochozoan, the Hawaiianbobtail squidEuprymna scolopes. Dev. Comp. Immunol. 33, 6976.

Cavalier-Smith, T., 1993. Kingdom protozoaand its18 phyla. Microbiol. Rev.57, 953994.Cheng, T.C., 1975. Functional morphology and biochemistry of molluscan phagocytes.

Ann. N. Y. Acad. Sci. 266, 343

379.Chowdhury, K.D., Sen, G., Biswas, T., 2010. Regulatory role of nitric oxide in the reducedsurvival of erythrocytes in visceral leishmaniasis. Biochim. Biophys. Acta Gen. Subj.1800, 964976.

Chu, F.L., 2000. Defense mechanisms of marine bivalves. In: Fingerman, M.,Nagabhushanam, R. (Eds.), Recent advances in marine biotechnology. Immunologyand Pathology, 5. Science Publishers Inc., Eneld, UK, pp. 142.

Chun, C.K., Scheetz, T.E., Fatima Bonaldo, M., Brown, B., Clemens, A., Crookes-Goodson,W.J., Crouch, K., DeMartini, T., Eyestone, M., Goodson, M.S., Janssens, B., Kimbell,

J.L., Koropatnick, T.A., Kucaba, T., Smith, C., Stewart, J.J., Tong, D., Troll, J.V.,Webster, S., Winhall-Rice, J., Yap, C., Casavant, T.L., McFall-Ngai, M.J., Soares, M.,2006. An annotated cDNA library of juvenile Euprymna scolopes with and withoutcolonization by the symbiont Vibrio scheri. BMC Genomics 7, 154.

Claes, M.F., 1996. Functional morphology of the white bodies of the cephalopodmolluscSepia ofcinalis. Acta Zool. 77, 173190.

Clarke, M.R., 1996. The role of cephalopods in the world's oceans: general conclusionsand the future. Philos. Trans. R. Soc. Lond. B 351, 11051112.

Cowden, R.R., 1972. Some cytological and cytochemical observations on leukopoieticorgans, the white bodiesofOctopusvulgaris. J. Invertebr. Pathol. 19, 113119.

Cowden, R.R., Curtis, S.K., 1973. Observations on living cells dissociated from leukopoieticorgan ofOctopus briareus. Exp. Mol. Pathol. 19, 178185.

Cowden, R.R., Curtis, S.K., 1981. Cephalopods. In: Ratcliffe, N.A., Rowley, A.F. (Eds.),Invertebrate blood cells. General Aspects, Animals Without True CirculatorySystems to Cephalopods, 1. Academic Press, London, UK, pp. 301323.

Czaker, R., 2006. Serotonin immunoreactivity in a highly enigmatic metazoan phylum,the pre-nervous Dicyemida. Cell Tissue Res. 326, 843850.

da Silva, P.M., Comesana, P., Fuentes, J., Villalba, A., 2008. Variability of haemocyte andhaemolymph parameters in European at oyster Ostrea edulis families obtainedfrom brood stocks of different geographical origins and relation with infection bythe protozoanBonamia ostreae. Fish Shellsh Immunol. 24, 551563.

Davey, H.M., 2002. Flow cytometric techniques for the detection of microorganisms.Methods Cell Sci. 24, 9197.

Davidson, S.K., Koropatnick, T.A., Kossmehl, R., Sycuro, L., McFall-Ngai, M.J., 2004. NOmeans yes in the squid-vibrio symbiosis: nitric oxide (NO) during the initialstages of a benecial association. Cell. Microbiol. 6, 11391151.

Di Cosmo, A., Di Cristo, C., Palumbo, A., d'Ischia, M., Messenger, J.B., 2000. Nitric oxidesynthase (NOS) in the brain of the cephalopod Sepia ofcinalis. J. Comp. Neurol.428, 411427.

Di Cristo, C., Fiore, G., Scheinker, V., Enikolopov, G., d'Ischia, M., Palumbo, A., Di Cosmo,A., 2007. Nitric oxide synthase expression in the central nervous system ofSepiaofcinalis: an in situ hybridization study. Eur. J. Neurosci. 26, 15991610.

Dobell, C.C., 1925. The life history and chromosome cycle ofAggregata eberthi(Protozoa:Sporozoa: Coccidia). Parasitology 17, 1136.

Ellis, R., Parry, H., Spicer, J.I., Hutchinson,T., Pipe, R., Widdicombe,S., 2011. Immunologicalfunction in marine invertebrates: responses to environmental perturbation. F ishShellsh Immunol. 30, 12091222.

European Parliament, Council of the European Union, 2010. Directive 2010/63/EU ofthe European Parliament and of the Council of 22 September 2010 on the Protec-tion of Animals Used for Scientic Purposes. Council of Europe, Strasbourg.

Farto, R., Armada, S.P., Montes, M., Guisande, J.A., Perez, M.J., Nieto, T.P., 2003. Vibriolentusassociated with diseased wild octopus (Octopus vulgaris). J. Invertebr. Pathol.83, 149156.

Ferl, J.P., 1988. Wound healing after arm amputation in Sepia ofcinalis(Cephalopoda:Sepioidea). J. Invertebr. Pathol. 52, 380388.

Finn, J.K., Hochberg, F.G., Norman, M.D., 2005. Phylum Dicyemida in Australian waters:rst record and distribution across diverse cephalopods hosts. Phuket Mar. Biol.

Cent. Res. Bull. 66, 83

96.Fisher, W.S., Dinuzzo, A.R., 1991. Agglutination of bacteria and erythrocytes by serum

from six species of marine mollusks. J. Invertebr. Pathol. 57, 380394.Ford, L.A., 1992. Host defense mechanisms of cephalopods. Annu. Rev. Fish Dis. 2, 2541.Ford, L.A., Alexander, S.K., Cooper, K.M., Hanlon, R.T., 1986. Bacterial populations of

normal and ulcerated mantle tissue of the squid, Lolliguncula brevis. J. Invertebr.Pathol. 48, 1326.

Furuya, H., 2008. A new dicyemid from Sepiella japonica (Mollusca: Cephalopoda:Decapoda). J. Parasitol. 94, 223229.

Furuya, H., 2009. Two new dicyemids from Sepia longipes (Mollusca: Cephalopoda:Decapoda). J. Parasitol. 95, 681689.

Furuya, H., 2010. A new dicyemid from Benthoctopus sibiricus(Mollusca: Cephalopoda:Octopoda). J. Parasitol. 96, 11231127.

Furuya, H., Tsuneki, K., 2003. Biology of dicyemid mesozoans. Zool. Sci. 20, 519532.Furuya, H., Tsuneki, K., Koshida, Y., 1997. Fine structure of dicyemid mesozoans, with

special reference to cell junctions. J. Morphol. 231, 297305.Furuya, H., Hochberg, F.G., Tsuneki, K., 2004a. Cell number and cellular composition in

infusoriform larvae of dicyemid mesozoans (Phylum Dicyemida). Zool. Sci. 21,877889.



8/9

Furuya, H., Ota, M., Kimura, R., Tsuneki, K., 2004b. Renal organs of cephalopods: a habitatfor dicyemids and chromidinids. J. Morphol. 262, 629643.

Garca Garca, J., Rodrguez Gonzlez, L., Garca Garca, B., 2004. Cost analysis of octopusongrowing installation in Galicia. Span. J. Agric. Res. 2, 531537.

Garcia, J.G., Garcia, B.G., 2011. Econometric model of viability/protability of octopus(Octopus vulgaris) ongrowing in sea cages. Aquacult. Int. 19, 11771191.

Garcia, J., Gonzalez, L., Garcia, B., 2004. Cost analysis of octopus ongrowing installationin Galicia. Span. J. Agric. Res. 2, 531537.

Gestal, C., Abollo, E., Arias, G., Pascual, S., 1997. Dicyema typus Van Beneden, 1876(Dicyema: Dicyemidae), un mesozoo parsito del rin de Octopus vulgarisCurier, 1797 (Mollusca: Cephalopoda) del noroeste de Espaa. Rev. Iber. Parasitol.

57, 85

87.Gestal, C.,Belcari, P., Abollo, E., Pascual, S., 1999a. Parasites of cephalopods in the northernTyrrhenian Sea (western Mediterranean): new host records and host specicity. Sci.Mar. 63, 3943.

Gestal, C., Pascual, S., Corral, L., Azevedo, C., 1999b. Ultrastructural aspects of the spo-rogony ofAggregata octopiana (Apicomplexa, Aggregatidae), a coccidian parasiteofOctopus vulgaris (Mollusca, Cephalopoda) from NE Atlantic coast.Eur. J. Protistol.35, 417425.

Gestal, C., Guerra, A., Abollo, E., Pascual, S., 2000.Aggregata sagittatan. sp. (Apicomplexa:Aggregatidae), a coccidian parasite from the European ying squid Todarodessagittatus(Mollusca: Cephalopoda). Syst. Parasitol. 47, 203206.

Gestal, C., Abollo, E., Pascual, S., 2002a. Observations on associated histopathology withAggregata octopiana infection (Protista: Apicomplexa) in Octopus vulgaris. Dis.Aquat. Org. 50, 4549.

Gestal, C., de la Cadena, M.P., Pascual, S., 2002b. Malabsorption syndrome observed inthe common octopusOctopus vulgarisinfected withAggregata octopiana(Protista:Apicomplexa). Dis. Aquat. Org. 51, 6165.

Gestal, C., Nigmatullin, C.M., Hochberg, F.G., Guerra, A., Pascual, S., 2005. Aggregataandresin. sp. (Apicomplexa: Aggregatidae) from the ommastrephid squid Martialia

hyadesi in the SW Atlantic Ocean and some general remarks onAggregataspp. incephalopod hosts. Syst. Parasitol. 60, 6573.

Gestal, C., Costa, M.M., Figueras, A., Novoa, B., 2007a. Analysis of differentiallyexpressed genes in response to bacterial stimulation in hemocytes of the carpet-shell clam Ruditapes decussatus: identication of new antimicrobial peptides.Gene 406, 134143.

Gestal, C., Guerra, A., Pascual, S., 2007b. Aggregata octopiana(Protista:Apicomplexa): adangerous pathogen during commercial Octopus vulgaris ongrowing. ICES J. Mar.Sci. 64, 17431748.

Gestal, C., Roch, P., Renault, T., Pallavicini, A., Paillard, C., Novoa, B., Oubella, R., Venier,P., Figueras, A., 2008. Study of diseases and the immune system of bivalves usingmolecular biology and genomics. Rev. Fish. Sci. 16, 133156.

Gestal, C., Pascual, S., Hochberg, F., 2010. Aggregata bathythermasp. nov. (Apicomplexa:Aggregatidae), a new coccidian parasite associated with a deep-sea hydrothermalvent octopus. Dis. Aquat. Org. 91, 237242.

Gonzalez, A.F., Pascual, S., Gestal, C., Abollo, E., Guerra, A., 2003. What makes a cepha-lopod a suitable host for parasite? The case of Galician waters. Fish. Res. 60,177183.

Gonzlez, A.F., Pascual, S., Gestal, C., Abollo, E., Guerra, A., 2003. What makes a cephalo-pod a suitable host for parasite? The case of Galician waters. Fish. Res. 60, 177 183.

Goodson, M.S., Kojadinovic, M., Troll, J.V., Scheetz, T.E., Casavant, T.L., Soares, M.B.,McFall-Ngai, M.J., 2005. Identifying components of the NF-kappa B pathway inthe benecialEuprymna scolopes Vibrio scheri light organ symbiosis. Appl. Envi-ron. Microbiol. 71, 69346946.

Grant, P., Zheng, Y., Pant, H.C., 2006. Squid (Loligo pealei) giant ber system: a modelfor studying neurodegeneration and dementia? Biol. Bull. 210, 318333.

Grossowicz, N., Ariel, M., Weber, T., 1979. Improved lysozyme assay in biological-uids.Clin. Chem. 25, 484485.

Hanlon, R.T., Forsythe, J.W., 1990a. Diseases of Mollusca: Cephalopoda. Diseases causedby microorganisms. In: Kinne, O. (Ed.), Diseases of marine animals. Introduction,Cephalopoda, Annelida, Crustacea, Chaetognatha, Echinodermata, Urochordata,III. Biologische Anstalt, Helgoland, Hamburg, Germany, pp. 2346.

Hanlon, R.T., Forsythe, J.W., 1990b. Diseases of Mollusca: Cephalopoda. Structural abnor-malities and neoplasia. In: Kinne, O. (Ed.), Diseases of marine animals. Introduction,Cephalopoda, Annelida, Crustacea, Chaetognatha, Echinodermata, Urochordata, III.Biologische Anstalt, Helgoland, Hamburg, Germany, pp. 203228.

Hanlon, R.T., Messenger, J.B., 1996. Cephalopod Behaviour. Cambridge University Press,

Cambridge, pp. 1

232.Hanlon, R.T., Hixon, R.F., Hulet, W.H., 1983. Survival, growth, and behavior of the loliginid

squids Loligo plei, Loligo pealei, and Lolliguncula brevis (Mollusca, Cephalopoda) inclosed seawater systems. Biol. Bull. 165, 637685.

Hanlon, R.T., Forsythe, J.W., Cooper, K.M., Dinuzzo, A.R., Folse, D.S., Kelly, M.T., 1984.Fatal penetrating skin ulcers in laboratory-reared octopuses. J. Invertebr. Pathol.44, 6783.

Hedgecock, D., Gaffney, P.M., Goulletquer, P., Guo, X.M., Reece, K., Warr, G.W., 2005.The case for sequencing the Pacic oyster genome. J. Shellsh. Res. 24, 429441.

Hochberg, F.G., 1990. Diseases of Mollusca: Cephalopoda. Diseases caused by Protistansand Metazoans. In: Kinne, O. (Ed.), Diseases of marine animals. Introduction,Cephalopoda, Annelida, Crustacea, Chaetognatha, Echinodermata, Urochordata,III. Biologische Anstalt, Helgoland, Hamburg, Germany, pp. 47202.

Hochner,B., 2008. Octopuses. Curr. Biol. 18, R897R898.Hochner, B., Shomrat, T., Fiorito, G., 2006. The octopus: a model for a comparative anal-

ysis of the evolution of learning and memory mechanisms. Biol. Bull. 210, 308317.Jacklet, J.W., 1997. Nitric oxide signaling in invertebrates. Inv. Neurosci. 3, 114.Kobayashi, M., Furuya, H., Holland, P.W.H., 1999. Evolution: Dicyemids are higher

animals. Nature 401, 762.http://dx.doi.org/10.1038/44513.

Kobayashi, M., Furuya, H., Wada, H., 2009. Molecular markers comparing the extremelysimple body plan of dicyemids to that of lophotrochozoans: insight from theexpression patterns ofHox,Otx, andbrachyury. Evol. Dev. 11, 582589.

Kopecn, J., Jirk, M., Obornk, M., Tokarev, Y.S., Luke, J., Modry, D., 2006. Phylogeneticanalysis of coccidian parasites from invertebrates: search for missing links. Protist157, 173183.

Li, H., Venier, P., Prado-Alvarez, M., Gestal, C., Toubiana, M., Quartesan, R., Borghesan, F.,Novoa, B., Figueras, A., Roch, P., 2010. Expression ofMytilus immune genes in re-sponse to experimental challenges varied according to the site of collection. FishShellsh Immunol. 28, 640648.

Licciardo, G.,Garziano, A.,Nocera, G.,Gaglio, G.,Marino, F.,De Vico, G.,2005. Contributo alla

conoscenza dell'azione patogena diAggregata octopiana(Apicomplexa: Aggregatidae)inOctopus vulgarisnel sud del Mar Tirreno. Ittiopatologia 2, 193198.Lpez, C., Carballal, M.J., Azevedo, C., Villalba, A., 1997. Morphological characterization of

the hemocytes of the clam, Ruditapes decussatus (Mollusca: Bivalvia). J. Invertebr.Pathol. 69, 5157.

Macan, M.C., Ludwig, W., Aznar, R., Grimont, P.A.D., Schleifer, K.H., Garay, E., Pujalte,M.J., 2001. Vibrio lentus sp. nov., isolated from Mediterranean oysters. Int. J. Syst.Evol. Microbiol. 51, 14491456.

Malham, S.K., Runham, N.W., 1998. A brief review of the immunology of Eledonecirrhosa. S. Afr. J. Mar. Sci. 20, 385391.

Malham, S.K., Runham, N.W., Secombes, C.J., 1997. Phagocytosis by haemocytes fromthe lesser octopus Eledone cirrhosa. Iberus 15, 111.

Malham, S.K., Coulson, C.L., Runham, N.W., 1998. Effects of repeated sampling on thehaemocytes and haemolymph ofEledone cirrhosa (Lam.). Comp. Biochem. Physiol.A: Mol. Integr. Physiol. 121, 431440.

Malham, S.K., Lacoste, A., Gelebart, F., Cueff, A., Poulet, S.A., 2002. A rst insight intostress-induced neuroendocrine and immune changes in the octopus Eledonecirrhosa. Aquat. Living Resour. 15, 187192.

Mather, J.A., 1995. Cognition in cephalopods. Adv. Study Behav. 24, 317353.

Mattiucci, S., Nascetti, G., 2008. Advances and trends in the molecular systematics ofanisakid nematodes, with implications for their evolutionary ecology and host-parasite co-evolutionary processes. Adv. Parasitol. 66, 47148.

Mayrand,E., St Jean, S.D., Courtenay, S.C., 2005. Haemocyte responses of blue mussels(Mytilus edulis L.) transferred from a contaminated site to a reference site: canthe immune system recuperate? Aquac. Res. 36, 962971.

McConnaughey, B.H., 1983. Mesozoa. In: Adiyodi, K.G., Adiyodi, R.G. (Eds.), Reproduc-tive biology of invertebrates. Oogenesis, Oviposition and Oosorption, I. John Wileyand Sons, New York, NY, pp. 135145.

McDade, J.E., Tripp, M.R., 1967. Mechanism of agglutination of red blood cells by oysterhemolymph. J. Invertebr. Pathol. 9, 523.

McFall-Ngai, M.J., 1994. Animalbacterial interactions in the early life history of marineinvertebrates: the Euprymna scolopes/Vibrio scheri symbiosis. Am. Zool. 34,554561.

McFall-Ngai, M.J., Nyholm, S.V., Castillo, M.G., 2010. The role of the immune system inthe initiation and persistence of the Euprymna scolopesVibrio scheri symbiosis.Semin. Immunol. 22, 4853.

Mladineo, I., Bocina, I., 2007. Extraintestinal gamogony of Aggregata octopiana in thereared common octopus(Octopus vulgaris) (Cephalopoda: Octopodidae). J. Invertebr.Pathol. 96, 261264.

Mladineo, I., Jozic, M., 2005. Aggregata infection in the common octopus, Octopusvulgaris (Linnaeus 1758), Cephalopoda: Octopodidae, reared in a ow-throughsystem. Acta Adriat. 46, 193199.

Nigmatullin, C.M., Shukhgalter, O.A., 1990. Helmintofauna y aspectos ecolgicos de lasrelaciones parasitarias del calamar (Illex argentinus) en el Atlntico Sudoccidental.Frente Maritimo 7A, 5768.

Nigmatullin, C.M., Shchetinnikov, A.S., Shukhgalter, O.A., 2009. On feeding and helminthfauna of neon ying squid Ommastrephes bartramii (Lesueur, 1821) (Cephalopoda:Ommastrephidae) in the southeastern Pacic. Rev. Biol. Mar. Oceanogr. 44, 227235.

Nolan, M.J., Cribb, T.H., 2005. The use and implications of ribosomal DNA sequencingfor the discrimination of digenean species. Adv. Parasitol. 60, 101163.

Novoa, B., Tafalla, C., Guerra, A., Figueras, A., 2002. Cellular immunological parametersof the octopus, Octopus vulgaris. J. Shellsh. Res. 21, 243248.

Nyholm, S.V., McFall-Ngai, M.J., 2004. The winnowing: establishing the squid-vibriosymbiosis. Nat. Rev. Microbiol. 2, 632642.

Nyholm, S.V., Stewart, J.J., Ruby, E.G., McFall-Ngai, M.J., 2009. Recognition betweensymbiotic Vibrio scheri and the haemocytes of Euprymna scolopes. Environ.

Microbiol.11, 483

493.Overstreet, R.M., Hochberg, F.G., 1975. Digenetic trematodes in cephalopods. J. Mar.

Biol. Assoc. UK 55, 893910.Pallavicini, A., Costa, M.M., Gestal, C., Dreos, R., Figueras, A., Venier, P., Novoa, B., 2008.

High sequence variability of myticin transcripts in hemocytes of immune-stimulated mussels suggests ancient host-pathogen interactions. Dev. Comp.Immunol. 32, 213226.

Palumbo, A., 2005. Nitric oxide in marine invertebrates: a comparative perspective.Comp. Biochem. Physiol. A: Mol. Integr. Physiol. 142, 241248.

Pardo-Gandarillas, M.C., Lohrmann, K.B., Valdivia, A.L., Ibez, C.M., 2009. First record ofparasites of Dosidicus gigas (d'Orbigny, 1835) (Cephalopoda: Ommastrephidae)from the Humboldt Current system off Chile. Rev. Biol. Mar. Oceanogr. 44, 397408.

Pascual, S., Guerra, A., 2001. Vexing question on sheries research: the study of ceph-alopods and their parasites. Iberus 19, 8795.

Pascual, S., Hochberg, F.G., 1996. Marine parasites as biological tags of cephalopodhosts. Parasitol. Today 12, 324327.

Pascual, S., Gonzlez, A., Arias, C., Guerra, A., 1995. Histopathology of larval Anisakissimplex B (Nematoda, Anisakidae), parasites of short-nned squid in the SENorth Atlantic. Bull. Eur. Assoc. Fish Pathol. 15, 160161.

http://dx.doi.org/10.1038/44513http://dx.doi.org/10.1038/44513


9/9

Pascual, S., Gestal, C., Estevez, J.M., Rodriguez, H., Soto, M., Abollo, E., Arias, C., 1996a.Parasites in commercially-exploited cephalopods (Mollusca, Cephalopoda) inSpain: an updated perspective. Aquaculture 142, 110.

Pascual, S., Gonzalez, A., Arias, C., Guerra, A., 1996b. Biotic relationships ofIllex coindetiiandTodaropsis eblanae(Cephalopoda, Ommastrephidae) in the Northeast Atlantic:evidence from parasites. Sarsia 81, 265274.

Pascual, S., Gestal,C., Abollo, E., 1997. EffectofPennella sp. (Copepoda,Pennellidae) on thecondition of Illex coindetii and Todaropsis eblanae (Cephalopoda, Ommastrephidae).Bull. Eur. Assoc. Fish Pathol. 7, 9195.

Pascual, S., Gonzlez, A.F., Arias, C., Guerra, A., 1999. Larval Anisakis simplex B(Nematoda: Ascaridoidea) of short-nned squid (Cephalopoda: Ommastrephidae)

in north-west Spain. J. Mar. Biol. Assoc. UK 79, 65

72.Pascual, S., Gonzlez, A.F., Gestal, C., Abollo, E., Guerra, A., 2001. Epidemiology ofPennella sp. (Crustacea: Copepoda), in exploited Illex coindetti stock in the NEAtlantic. Sci. Mar. 65, 307312.

Pascual, S., Vega, M.A., Rocha, F.J., Guerra, A., 2002. First report of an endoparasiticepicaridean isopod infecting cephalopods. J. Wildl. Dis. 38, 473477.

Pascual, S., Rocha, F., Guerra, A., 2006. Gross lesions in the Hubb octopus Octopushubbsorum. Mar. Biol. Res. 2, 420423.

Pascual, S., Gonzalez, A., Guerra, A., 2007. Parasites and cephalopod sheries uncertainty:towards a waterfall understanding. Rev. Fish Biol. Fish. 17, 139144.

Pascual, S., Gonzlez, A.F., Guerra, A., 2010. Coccidiosis during octopus senescence: pre-paring for parasite outbreak. Fish. Res. 106, 160162.

Petric, M., Mladineo, I., Sifner, S.K., 2011. Insight into the short-nned squid Illexcoindetii(Cephalopoda: Ommastrephidae) feeding ecology: is there a link betweenhelminth parasites and food composition? J. Parasitol. 97, 5562.

Pipe, R.K., 1992. Generation of reactive oxygen metabolites by the hemocytes of themusselMytilus edulis. Dev. Comp. Immunol. 16, 111122.

Poynton, S.L., Reimschuessel, R., Stoskopf, M.K., 1992. Aggregata dobelli n. sp. andAggregata millerorumn. sp. (Apicomplexa, Aggregatidae) from two species of octo-

pus (Mollusca, Octopodidae) from the Eastern North Pacic-Ocean. J. Protozool. 39,248256.

Prado-Alvarez, M., Gestal, C., Novoa, B., Figueras, A., 2009. Differentially expressedgenes of the carpet shell clam Ruditapes decussatus against Perkinsus olseni. FishShellsh Immunol. 26, 7283.

Randhawa, H.S., 2011. Insights using a molecular approach into the life cycle of a tape-worm infecting great white sharks. J. Parasitol. 97, 275280.

Rivero, A., 2006. Nitric oxide: an antiparasitic molecule of invertebrates. TrendsParasitol. 22, 219225.

Robertson, J.D., Bonaventura, J., Kohm, A.P., 1994. Nitric oxide is required for tactilelearning inOctopus vulgaris. Proc. R. Soc. Lond. B 256, 269273.

Rodrguez-Domnguez, H., Soto-Ba, M., Iglesias-Blanco, R., Crespo-Gonzlez, C., Arias-Fernndez, C., Garca-Estvez, J., 2006. Preliminary study on the phagocytic abilityof Octopus vulgaris Cuvier, 1797 (Mollusca: Cephalopoda) haemocytes in vitro.Aquaculture 254, 563570.

Rgener, W., Renwrantz, L., Uhlenbruck, G., 1985. Isolation and characterization of aLectin from the hemolymph of the cephalopod Octopus vulgaris (Lam) inhibitedby Alpha-D-lactose and N-acetyl-lactosamine. Dev. Comp. Immunol. 9, 605616.

Salimi, L., Jamili, S., Motalebi, A., Eghtesadi-Araghi, P., Rabbani, M., Rostami-Beshman,M., 2009. Morphological characterization and size of hemocytes in Anodontacygnea. J. Invertebr. Pathol. 101, 8185.

Sardella, N.H., Roldn, M.I., Tanzola, D., 1990. Helmintos parsitos del calamar ( Illexargentinus) en la subpoblacin Bonaerense-Norpatagnica. Frente Maritimo 7A,5358.

Sardella, N.H., Re, M.E., Timi, J.T., 2000. Two new Aggregata species (Apicomplexa:Aggregatidae) infecting Octopus tehuelchus and Enteroctopus megalocyathus

(Mollusca: Octopodidae) in Patagonia, Argentina. J. Parasitol. 86, 1107

1113.Schipp, R., 1987. General morphological and functional characteristics of the cephalo-pod circulatory system. An introduction. Experientia 43, 474477.

Semmens, J.M., Pecl, G.T., Gillanders, B.M., Waluda, C.M., Shea, E.K., Jouffre, D., Ichii, T.,Zumholz, K., Katugin, O.N., Leporati, S.C., Shaw, P.W., 2007. Approaches to resolvingcephalopod movement and migration patterns. Rev. Fish Biol. Fish. 17, 401423.

Shukhgalter, O.A., Nigmatullin, C.M., 2001. Parasitic helminths of jumbo squidDosidicus gigas (Cephalopoda: Ommastrephidae) in open waters of the centraleast Pacic. Fish. Res. 54, 95110.

Stunkard, H.W., 1954. The life-history and systematic relations of the Mesozoa. Q. Rev.Biol. 29, 230244.

Suzuki, T.G., Ogino, K., Tsuneki, K., Furuya, H., 2010. Phylogenetic analysis of dicyemidmesozoans (phylum Dicyemida) from innexin amino acid sequences: dicyemidsare not related to Platyhelminthes. J. Parasitol. 96, 614625.

Trilles, J.P., Oktener, A., 2004.Livoneca sinuata (Crustacea; Isopoda; Cymothoidae) onLoligo vulgaris from Turkey, and unusual cymothoid associations. Dis. Aquat. Org.61, 235240.

Tripp, M.R., 1963. Cellular responses of mollusks. Ann. N. Y. Acad. Sci. 113, 467.Tripp, M.R., 1974. Molluscan immunity. Ann. N. Y. Acad. Sci. 234, 23 27.

Vaz-Pires, P., Seixas, P., Barbosa, A., 2004. Aquaculture potential of the common octo-pus (Octopus vulgarisCuvier, 1797): a review. Aquaculture 238, 221238.

Vidal, E.A.G., Haimovici, M., 1998. Feeding and the possible role of the proboscis andmucus cover in the ingestion of microorganisms by rhynchoteuthion paralarvae(Cephalopoda: Ommastrephidae). Bull. Mar. Sci. 63, 305316.

Vidal, E.A.G., Haimovici, M., 1999. Digestive tract parasites in rhynchoteuthion squidparalarvae, particularly in Illex argentinus (Cephalopoda: Ommastrephidae). Fish.Bull. 97, 402405.

Wang, Y.L., Dufour, Y.S., Carlson, H.K., Donohue, T.J., Marletta, M.A., Ruby, E.G., 2010. H-NOX-mediated nitric oxide sensing modulates symbiotic colonization by Vibrioscheri. Proc. Natl. Acad. Sci. U.S.A. 107, 83758380.

Wells, M.J., Smith, P.J.S., 1987. The performance of the Octopuscirculatory system: a tri-umph of engineering over design. Experientia 43, 487499.


Pathogens and Immune Response of Cephalopods

Documents

Transcript of Pathogens and Immune Response of Cephalopods