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Transcript of Effect of Thermal, Oxidative, Acidic, Osmotic, or Nutritional.pdf
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7/27/2019 Effect of Thermal, Oxidative, Acidic, Osmotic, or Nutritional.pdf
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Microb Ecol (1994) 27:57-63
MICROBIAL
ECOLOGY
1994 Springer-Verlag Ne w York Inc.
Effect of Therm al Oxidative Acidic Osmo tic or Nutritional
Stresses on Subsequent Culturability of scher ich ia cob in Seawater
P.M. Munro, R.L. C16ment, G.N. Flatau, M.J. Gauthier
Inst i tut National de la Sant6 et de la Recherche M6dicale, Unit6 303, C.E .R.B .O.M ., I Avenu e
Jean Lorrain, 06300 Nice, France
Received: 22 July 1993; Revised: 29 September 1993
Abstract. Survival o f stressed
Escherichia coli
with or w ithout the
rpoS
gene
was assessed after 2 and 6 days in sterile seawater. Cells were submitted to
thermal (48C), acidic (pH 5.1), oxidative (H202 lrnM), nutritional (C, N, P
starvation), or osm otic (NaCI 0.5M) stresses for periods ranging f rom 0 to 4 h.
We found a stress-mediated cross protection against seawater relative to con-
trols. Viability was higher when cells were acid, oxidatively, nutritionally or
osm otically stressed. Su rvival increased in cells stressed at 37C as compar ed
with 20C. With the exception of osmotic stress, we found that this stress-
induced cross protect ion was
rpoS
dependent.
Introduction
To su rvive in the marine environ men t, enteric bacteria have devel ope d a strategy in
which they shift into various states [for review see 18], undergoing dramatic
physiological and morphological changes [5, 15]. Nevertheless, i t has been shown
that the fate of these bacteria in seawater can d epend on the history o f the cells prior
to their arrival in this nutrient-poor environm ent [4]. For examp le,
Escherichia coli
and other enteric bacteria grown in a high-salt medium survive better in seawater
[3, 16]. The sam e kind o f survival enhancem ent has been described with stationary
phase cells [6], suggesting a poss ible adaptation to starvation via the express ion of
specific genes, also called survival genes [11, 20], related to nutrient-deprived
environm ents [ 13]. This resistance to starvation cou ld be under the control of stress
proteins [13].
This paper describes stresses-mediated resistance to seawater in
E. coli
and the
influence o f the duration o f stresses on cell culturability. W e su ggest that this cross
protection against seawater, achieved by a thermal, oxidative, acidic, osmotic, or
nutritional stress may b e in some cases under the control of
rpoS
a regulatory g ene
of central importance for early stationary phase-indu ced gene s in
E. coli
[7].
Correspondence to: P.M. Munro .
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58 P . M . M u nr o e t a l .
a t e r i a ls a n d e t h o d s
B a c t e r i a l S t r a i n s a n d G r o w t h C o n d i t i o n s
Escherichia coli M C 4 1 0 0 ( F - A arg-lac) U169araD139 rpsL150ptsF25 lbB5301 rbsR deoC relA1)
a n d R H 9 0 , a
rpoS
m u t a n t o f t h i s s t r a i n ( M C 4 1 0 0
rpoS359::Tn10)
[ 12 ] , w e r e u se d . S to c ks w e r e
m a i n t a i n e d a t - 7 0 C i n tr y p t ic s o y b r o t h (D i f c o L a b o r a to r i e s, D e t r o i t , M i c h . , U S A ) s u p p l e m e n t e d
w i th g lyc e r o l ( 10 v /v ) . F o r e xpe r im e n t s , c e l l s w e r e g r ow n a t 37 C in m in im a l M O P S m e d ium [ 17 ]
( pH 7 . 4 ) su pp le m e n te d w i th g luc ose ( 2 g / l ) a nd phosp ha te ( N a 2H P O 4 , 2 m M ) .
S t r e s s C o n d i t i o n s
B e f o r e t r a ns f e r t o s e a w a te r , c e l l s w e r e subm i t t e d t o one o f f i ve d i f f e r e n t s t r e s s c ond i t i ons : h igh
temp era ture (48C -+ 0 .2C) , h ig h osm ola r i ty (NaC1, 0 .5 M) , ac id i ty (pH 5 .1 -+ 0 .4) , h ig h pe roxide
c o n c e n t ra t i o n ( H 2 0 2 , 1 n ~ ) , a n d n u t r i e n t s t a rv a t io n ( M O P S m e d i u m w i t h o u t c a rb o n , n i t r o g e n , a n d
phosph o r us sou r c e s ) .
S u r v i v a l T e s t s
S ur v iva l t e s t s w e r e pe r f o r m e d in 100 m l o f a u toc l a ve d se a w a te r ( 113 C , 20 m in ) ( S S W ) ( C a pe o f N ic e ,
F r a nc e ) he ld i n 250 - m l E r l e nm e y e r fl a sks ( f u r the r r e f e r re d t o a s m ic r oc osm s) . C e l l s w e r e g r ow n in 100
m l o f M O P S m e d ium a t 37C a n d ha r ve s t e d at e a r ly e xpone n t i a l pha se o f g r ow th ( m 6o = 0 . 3 ) by
c e n t r i f uga t ion ( 27 , 000 g , 6 m in , 20 C ) . The y w e r e t he n su spe n de d , a t t he de ns i ty o f t he o r ig ina l
c u l tu r e , i n 6 s a m p le s ( 120 m l ) o f ne w M O P S m e d ium a nd subm i t t e d t o s t re s s c ond i t i ons . S usp e ns ions
w e r e i nc uba t e d a t 37 C , e xc e p t f o r t he r m a l s t r e s s ( 48 C ) . F o r e a c h su spe ns ion , a 20 - m l s a m p le w a s
c o l l e c t e d a ft e r 0 m in , 30 m in , l h , 2h , 3h , a nd 4h o f s t r e s s e xposu r e a n d c e n t r i f uge d ( 27 , 000 g , 6 r a in ,
20 C ) . C e l l s w e r e w a she d 3 t im e s w i th 25 m l o f S S W , the l a s t pe ll e t su spe nd e d in 2 m l o f S S W , a nd
th i s fi na l su spe ns ion w a s u se d to i noc u la t e m ic r oc osm s a t a de ns i ty o f 1 . 0 x 1 6 c f u /m l ( - +0 .5 x l 6
c f u /m l ) . M ic r o c osm s w e r e t he n inc uba t e d i n t he da r k a t r oom t e m pe r a tu r e ( 22 - 25 C ) .
S e pa r a t e s e t s o f e xpe r im e n t s , w h ic h f o l l ow e d the ba s i c p r o toc o l ou t l i ne d a bove , w e r e u se d to
e xa m ine the i n f lue nc e o f t e m pe r a tu r e on s t r e s s - induc e d c r o s s p r o t e c t i on a nd the de pe nde nc y o f c r o s s
p r o t e c t i on on the rpoS ge ne . S uspe ns ions w e r e e xpose d to s t r e s s c ond i t i ons a t 20 C f o r 3h f o r
c om pa r i son w i th t he r e su l t s ob t a ine d w i th e xposu r e a t 37 C . The r o l e o f rpoS w a s e x a m i n e d i n
e xpe r im e n t s c om pa r ing su r v iva l o f M C 4 100 a nd R H 9 0 s t r a in s . C e l l s w e r e e xpose d to s t r e s s c ond i t i ons
f o r l h a t 37C .
C u l t u r a b l e - C e l l s C o u n t s
A l l m ic r oc o sm s w e r e s a m p le d im m e d ia t e ly a f t e r i noc u la t i on (TO ) a nd a f t e r 2 a nd 6 da ys o f i nc uba t ion
in s e a w a te r. The c o lony f o r m ing a b i l i t y o f c e l l s w a s de t e r m ine d in t r ip l i c a t e by the m e m br a n e f il t r a t ion
t e c hn ique ( M ic r o F i l t r a t i on S ys t e m s f i l t e r s , po r e s i z e , 0 . 45 I xm ; M F S , D ub l in , C a l i f . , U S A ) on
nu t r i e n t a ga r ( D i fc o ) . A n a pp r op r i a t e d i l u t ion o f t he s a m p le s w a s u se d to y i e ld a num be r o f c o lon ie s
r a ng in g f r om a bou t 10 to 400 pe r p l a t e. C o lon ie s w e r e c o un te d on th e f il t e r s suppo r t e d on a ga r p l a t es
a f t e r a 24 - h i nc ub a t ion a t 37 C . L oss o f c u l tu r a b i l i t y w a s e xp r e s se d a s ( c f u /m l a f t e r 2 a nd 6 da ys o f
inc uba t ion in s e a w a te r ) / ( c f u /m l a t TO ) x 100 ( c u l tu r a b l e c e l l s) .
S t a t i st i c a l A n a l y s i s
A l l da t a p r e se n t e d a r e m e a ns f r om tw o se pa r a t e e xpe r im e n t s . A na ly s i s o f va r i a nc e w a s pe r f o r m e d on
the l og - t r a ns f o r m e d da t a i n o r de r t o s t a b i l i z e t he va r i a nc e .
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Survival o f Stressed
Escherichia coli
in Seawater 9
t O
0
m
03
r j
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o
, 0 1
,001
,0001
,00001
,000001
T h e r m a l
0 3 0 6 0 12 0 1 8 0
1 0
,01
,001
4 0
O x i d a t i v e
,1
o i
,oo1 ~
o o o 1
z z ~
, o o o o l ~ N . N . N .~
0 30 60 120 180
O s m o t i c
~ ~
~I ~ ~ ~
0 30 ~ 120 180 240
2 4 0
A c i d i c
,1
,01
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S t a r v a t i o n
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1 ~ ' A ;., ~: ~ / / / . / / /
r . . /~ 7 / , i i l ~ l t
l V tA / f l ; 1 // ,., 1~ : 7 /
,o o o, N . N . ~ ' ~ : > + '..~ . N
0 3 0 6 0 1 2 0 1 0 0 2 4 0
D u r a t io n o f s t r e s s ( m i n )
Fig. 1. Percen tage of culturable cells o f stressed E . c o l i M C 4100 after a 6-day incubation in
seawa ter. Cells were su bm itted to different stresses for different periods of t ime see M aterials and
M ethods) at 37C prior to their incubat ion in seawater . B a r s represent standard deviations of two
different experiments.
R e s u l t s
I n f l u e n c e
of Previous Stress on Resistance to Seawa ter
A f t e r 2 d a y s o f i n c u b a t i o n i n s e a w a t e r , n o s i g n i f ic a n t e f f e c t o f s tr e s s o n r e s i s t a n c e
o f E . c o l i t o s e a w a t e r w a s d e t e c t e d d a ta n o t s h o w n ) . H o w e v e r , d a ta o b t a in e d a f te r
6 d a y s o f in c u b a t i o n F i g . 1 ) s h o w e d t h a t a p r e v i o u s e x p o s u r e t o a s t re s s a l l o w e d a
b e t t e r r e s i s t a n c e t o s e a w a t e r .
W i t h t h e e x c e p t i o n o f a c i d i c s t r e ss , v i a b i l i ty i n c r e a s e d w i t h d u r a t i on o f e x p o s u r e
w i t h i n t h e t e s te d l im i t s ) u p t o a m a x i m u m l e v e l , w h i c h d i d n o t c h a n g e w i t h fu r t h er
e x p o s u r e . T h e d u r a t io n o f e x p o s u r e y i e l d i n g m a x i m u m v i a b il it y i n s e a w a t e r va r ie d
w i t h t h e s tr e s s fa c to r : 6 0 m i n f o r o s m o t i c a n d t h e r m a l s t r e s se s , 1 2 0 m i n f o r
s t a r v a t i o n s tr e s s , a n d 1 8 0 r a i n f o r o x i d a t i v e s t r e s s . F o r a c i d i c s t r e s s t h is l e v e l
i n c r e a s e d u p t o 1 2 0 m i n t h e n d e c r e a s e d .
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60 P.M. Mu nro et al.
tg~
0
_
;g
,000
,0000
,00000
T p o x ca r o s m
t r e s s e s
Fig. 2. Percentag e of culturable cells of stressed
E. coli MC 4100 after a 6-day incubation in
seawater. Cells we re previously stressed for 3 h at
20C T = no stress, pH = acidic stress,
ox = oxidative stress, car = starvation stress,
osm = osmotic stress). For ease of comparison,
data from the 37C experiment under the same
conditions Fig. l) have been included here.
Bars
represent standard deviations of tw o d ifferent
experiments.
T h e r e l a t i v e e f f e c t o f th e s e s t r e ss e s o n t h e r e s i s t a n c e o f c e l ls t o s e a w a t e r f o l l o w e d
t h e s e q u e n c e : o s m o t i c > s t a r v a t io n > o x i d a t i v e > a c id i c > t h e r m a l . O s m o t i c
s t re s s a l s o p r o v i d e d t h e b e s t p r o t e c t i v e e f f e c t w i t h i n t h e s h o r t e s t t i m e p e r i o d .
W h e n t h e s e s t r e s s e s w e r e a p p l i e d a t 20 C f o r 3 h , a s i g n i f i c a n t l e v e l o f p r o t e c t i o n
w a s o b s e r v e d o n l y i n t h e c a s e o f o s m o t i c P < 0 . 0 1 ) a n d s t a r v a t i o n s t r e s s e s
P < 0 . 0 5 ) F i g . 2 ) , t h u s c o n f i r m i n g t h e ir g r e a t e r e f f e c t . A t 2 0 C n o s i g n i f ic a n t
d i f f e r e n c e s i n v i a b i l i t y w e r e f o u n d f o r c e l l s r e c e i v i n g e i t h e r a c i d i c o r o x i d a t i v e
s t r e s se s .
D ep en d en ce o f S tr e s s - In d u ced Pr o t ec t i o n t o r p o S = k a t F )
W i t h t h e e x c e p t i o n o f o s m o t i c a l l y s t r e s s e d c e ll s , a s i g n i f ic a n t l y h i g h e r l e v e l o f
r e s i s t a n c e t o s e a w a t e r w a s o b s e r v e d w i t h s t r e s s e d r p o S c e l l s P < 0 . 0 5 f o r
o x i d a t i v e a n d a c i d i c s t r e s s a n d P < 0 . 0 1 f o r t h e r m a l a n d n u t r i t i o n a l s t r e s s e s )
r e l a t iv e t o t h e m u t a n t F i g . 3 ) . T h u s , c r o s s p r o t e c t i o n t o s e a w a t e r t h r o u g h o x i d a -
t i v e , a c i d i c , t h e r m a l , a n d n u t r i ti o n a l s t r e s s e s a p p e a r s t o b e
r p o S
d e p e n d e n t ,
w h e r e a s s u c h p r o t e c t i o n t h r o u g h o s m o t i c s t r e s s d o e s n o t .
i s cu s s i on
T h i s s t u d y d e m o n s t r a t e s a t h e r m a l , o x i d a t i v e , a c i d i c , o s m o t i c , a n d n u t r i t i o n a l
s t r e s s -i n d u c e d c r o s s p r o t e c t i o n a g a i n s t s e a w a t e r F i g . 1 ) . W h i l e f o r E. col i , p r o -
l o n g e d p e r i o d s i n s e a w a t e r r e p r e s e n t b o t h a n o s m o t i c a n d a n u t ri t io n a l s t re s s , w e
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Survival of Stressed Escherichia coli in Seawater 61
10
o
,01
,001
,0001
T tern p ox car osm
Stresses
Fig. 3. Percentage of culturable cells of stressed.
E. coli MC 4100 rpoS+) and RH 90 rpoS-) after
a 6-day incubation in seawater. Cells were
previously stressed for 1 h as described in
Materials and Methods (T = no stress,
tern = thermal stress, pH = acidic stress,
ox = oxidative stress, car = starvation stress,
osm = osmotic stress). Bars represent standard
deviations of two different experiments.
conc lude tha t the r e i s a mul t ip le - s t r es s - induced c ross pro tec t ion of E. co l i to
osmot ic and nu t r i t iona l cha l lenge .
This e f f ec t has b een ve r i f i ed for a l l the t e s ted s t r e s s f ac tor s , bu t i s mo re or l e s s
impor tan t depending on the s t r e s s . Osmot ica l ly s t r e s sed ce l l s and nu t r ien t - s ta rved
ce l l s show h igh er surv iva l r a tes in seaw ate r (F ig . 1 ). O ur da ta sugges t tha t th is i s
a l so depende nt on the t emp era ture a t whic h the ce l l s a r e s tr e s sed . P ro tec t ion aga ins t
seaw ate r is no t ach ieve d a f te r a 3 -h ac id ic or ox ida t ive s t r e s s a t 20C, whe reas ce l l s
s t r e s sed a t 37C in o the rwise the same condi t ions a r e approximate ly 10 t imes and
3 , 000 t i m e s , r e s pe c t i ve l y , m o r e r e s i st a n t t o s e a wa t e r t ha n t hos e t ha t a re uns t r e ss e d
(F ig . 2 ) . A s ign i f ican t l eve l o f p ro tec t io n wi th s t r e ss a t 20C i s ach ieved only wi th
osmotic and nutr i t ional s t ress (Fig. 2) .
P r e v i ous s t ud i e s f r om t h is l a bo r a t o r y ha ve a dd r e s s e d t he i n f lue nc e o f g r owt h
c ond i t ions on s u r v i va l o f E . co i l in seaw ate r [4] . Escher ich ia co l i ce l l s submi t ted to
an osm ot ic s t r e s s (growth in a h igh sa l t medi um ) or to a nu t r i t iona l s t r e s s ( s ta t ionary
pha s e c e l ls ) ha ve be e n s h own t o m a i n t a i n c u l t u r a b i li t y a f t e r p r o l ong e d pe r i ods i n
seaw ate r [3 , 6 ] .
S t a r va t i on - i nduc e d c r o s s p r o t e c t i on o f E. co l i aga ins t hea t o r H202 [8] and
os m ot i c c ha l l e nge [ 9 ] , a nd s t a r va t i on - i nduc e d c r o s s p r o t e c t i on o f E. co l i and
m a r i ne Vibr io spp . aga ins t l e tha l t empera tures [10] have been c lea r ly demon-
s t ra t ed . On t he o t he r ha nd , t he s a m e k i nd o f t he r m o t o l e r a nc e a nd r e s i s t a nc e a ga i n s t
hyd r oge n pe r ox i de c a n be o s m o t i c a l l y s t i m u l a t e d i n E. co i l [7].
Co mb ar ro e t a l. [ 2] have a l r eady in ves t iga ted the e f f ec t o f an ox ida t ive s t r e s s a t
23 - 25 C on f u r t he r s u r v i va l o f E. co l i in seawate r th rough a t r ans ien t incuba t ion
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62 P . M . M unr o e t a l .
f rom anaerob ic g rowth med ium ( in t es t i na l o r u r inary l i ke cond i t i ons ) t o aerob ic
f resh o r was t e water . Th ey foun d the percen t age o f cu l tu rab l e ce l l s a ft e r 7 days i n
seaw ater t o be t he sam e as i n t h is s t ud y ( abou t 0 .0001) fo r a 3 -h incubat ion t ime in
wa s t e water . H ow eve r , t he cond i t i ons used in bo th s tud i es canno t a l l ow any fu r ther
conclus ion .
The da t a p resen t ed he re supp or t t he observa t ions t ha t mu l t ip l e - s tr ess r es i s t ance i s
as e f f i c i en t fo r ce l l s i n cu l tu re as i n seaw ater su rv iva l .
T h e d e p e n d e n c e o n rpoS of c ross p ro tec t i on aga ins t seaw ater induce d b y thermal ,
oxidat ive, acid ic , and nut r i t ional s t resses (Fig . 3) i s suppor ted by the f indings that
Ka tF ( - -Rpo S) m utan t s fa i l t o deve lop thermores i s t ance , o sm ores i s t ance , o r r es i s-
t ance t o H202 and have r educed v i ab i l i t y under severa l s t a rva t ion cond i t i ons [12 ,
19] . Thus,
rp o S
which has been iden t i f i ed as a cen t ra l r egu la to r o f t he genera l
s t a rva t ion r esponse [12 , 14 ] , appear s a l so t o be impor t an t i n mul t i p l e - s t r ess - in -
duc ed r es is t ance t o seaw ater . I t has a l so been dem ons t ra t ed [12 , 14 ] t ha t severa l
rpoS-dependent
pro t e ins were n o t osmo t i ca l l y i nduced , t hus e xp la in ing the f ac t t ha t
osm ot i c c ross p ro t ec t i on aga ins t seaw ater is no t
rpoS-dependent.
I n s u m mar y , i n d ep en d en tl y o f li g h t an d p r ed a ti o n , l o n g k n o w n t o b e s o me o f t h e
ma in f ac to r s a f f ec ti ng the su rv iva l o f bac t e r i a i n seaw ater [1 ] , enhanc ed r es i s t ance
o f
E. coli
t o seawater can be ach i eved by a p rev ious ac id i c , t hermal , ox ida t ive ,
osm ot i c , o r nu t ri ti ona l s t r ess . W i th the exc ep t ion o f osm ot i c s t r ess , t hi s c ross
p ro t ec t i on i s p robab ly assoc i a t ed wi th rpoS a pu t a t i ve s igma fac to r o f cen t ra l
impor t ance fo r ear ly s t a t i onary -phase- induced genes [7 ] . I t has been assumed tha t
rpoS
i s a l so o f majo r impor t ance i n su rv iva l o f
E. coli
i n f eas t and f am ine [7]
cond i t i ons i n t he env i ronm ent , and w e sugg es t tha t i t i s espec i a l l y impor t an t du r ing
the s t r ess - inducing t r ans i t f rom the hum an in tes t ina l o r u r inary t r ac t t o seaw ater v i a
w as t ew a t e r .
S t u d i es a r e u n d e r w ay t o ch ec k f o r a p o s s i b l e
de novo
pro t e in syn thes i s depen-
denc e o f th i s mul t i p l e - s tr ess - induced c ross p ro t ec t i on aga ins t seaw ater .
A c k n o w l e d g m e n t s . W e t h a n k D r . R e g i n e H e n g g e - A r o n i s f o r k i n d l y p r o v i d i n g t he E . c o l i s t r a in s . W e
a r e g r at e f ul t o D r . J o h n D o l a n f o r h e lp f u l c o m m e n t s a n d r e v i e w s o f t h e m a n u s c r ip t . T h i s w o r k w a s
p a r t ly s u p p o r t e d b y t h e P r o g r a m m e N a t i o n a l d O c r a n o g r a p h i e c r t i ~ r e ( P N O C ) .
e f e r ence s
1 . C a r luc c i A F , P r a m e r D ( 1959 ) F a c to r s a f f e c t i ng t he su r v iva l o f ba c t e r i a i n s e aw a te r . A pp l
M i c r o b i o l 7 : 2 4 3 - 2 4 7
2 . C om ba r r o M - P , G a u th i e r M J , F l a t a u G N , C 16m e n t R ( 1992 ) E f f e c t o f a t r a ns i e n t i nc uba t ion in
w a s t e w a te r on t he s e ns i t i v i t y t o s e a w a te r o f Esc he r i c h ia c o l i c e l l s g r ow n unde r i n t e s t i na l - l i ke
c o n d i t io n s . B i o m e d L e t t 4 7 : 1 8 5 - 1 9 0
3 . G a u t h i e r M J , M u n r o P M , M o h a j e r S (1 9 8 7 ) I n f lu e n c e o f s al t s a n d s o d i u m c h l o r i d e o n th e r e c o v e ry
o f E s c h e r i c h i a c o l i f r om se a w a te r . C u r r M ic r ob io l 15 :5 - 10
4 . G a u t h i e r M J , M u n r o P M , B r e i t t m a y e r V A ( 1 9 8 9 ) In f l u e n c e o f p r io r g r o w t h c o n d i ti o n s o n lo w
nu t r i e n t r e sponse o f
Esc he r i c h ia c o l i
i n s e a w a te r . C a n J M ic r ob io l 35 :37 9 - 383
5 . G a n t h i e r M J , T h o m a s P , M u n r o P M ( 1 9 8 9 ) M o d i f i c a ti o n d e la s t ru c t u re d es e n v e l o p p e s e t d u
c o n t e n u e n p r o t r i n e s d Esc he r i c h ia c o l i e n s u r v i e d a n s l e a u d e m e r . C a n J M i c r o b i o l 3 5 : 8 4 3 - 8 4 9
6 . G a u t h i e r M J , F l a ta u G N , C l e m e n t R L , M u n r o P M ( 1 9 9 2 ) S e n s it i v it y o f Esc he r i c h ia c o l i ce l ls to
se a w a te r clo se ly de pe nds on the i r g r ow th s t a ge . J A pp l B a c t e r io l 73 :25 7 - 26 2
-
7/27/2019 Effect of Thermal, Oxidative, Acidic, Osmotic, or Nutritional.pdf
7/7
S urv i va l o f S t r e sse d
E s c h e r i c h i a c o l i
in Seaw ate r 63
7 . He ngg e -Aron i s R , La nge R , He nne be rg N , F i s c he r D 1993) O smot i c r e gu l a ti on o f r p o S - d ep en -
dent genes in
E s ch er i ch i a co l i .
J Bac te r io l 175:259-265
8. Jenkins DE, S chul tz JE, M at in A 1988) S ta rva t ion- induced c ross protec t ion aga ins t hea t or H202
cha l lenge in E s ch er i ch i a co l i . J B a c t e r i o l 170 : 3910-3914
9. Jenkins DE , Cha isson SA, Mat in A 1990) S ta rva t ion- indu ced c ross protec t ion aga ins t osm ot ic
cha l lenge in
E s ch er i ch i a co l i .
J Bac te r io l 172:2779-2781
10. Joupe r - J a an A, Good ma n A E, Kj e l l e be rg S 1992) B a c t e r ia s ta rve d fo r p ro longe d pe r iods i n -
c reased protec t ion aga ins t l e tha l t empera tures . FEMS Microbiol Ecol 101:229-236
11. Ko l te r R 1992) Li fe and dea th in s ta t ionary phase . A SM N ew s 58:75-7 9
12. Lan ge R, Hen gge-A ronis R 1991) Ident i f ica t ion of a cent ra l regula tor of s ta t ionary-phase gene
express ion in E s c h e r i c h i a c o i l M o l M i c r o b io l 5 : 4 9 - 5 9
13. M at in A 1991) The mo lecula r basi s of ca rbon-s ta rva t ion- induced genera l re s i stance in E s c h e -
r i ch i a co l i . M o l M i c ro b i o l 5 : 3 - 1 0
14. M cCan n MP , K idwel l JP , Mat in A 1991) Th e puta t ive s igma fac tor Ka tF has a cent ra l ro le in
deve lo pm ent of s ta rva t ion-media ted gene ra l re s i s tance in
E s ch er i ch i a co l i .
J B a c t e r i o l 173 : 4188-
4194
15. Mun ro P M , Ga u t h ie r MJ , La umon d F M 1987) C ha nge s i n
E s c h e r i c h i a c o l i
s ta rved in seaw ate r or
g rown i n s e a w a t e r -wa s t e wa t e r m i x t u res . A pp l Env i ron Mi c rob i o l 53 :1476-1481
16 . Mu nro P M , L a umond F , Ga u t h i e r MJ 1987) A p re v i ous g rowt h o f e n t e ri c ba c t er i a on a s a lt e d
me d i um i nc re ase t he i r su rv i va l in s e a wa t e r. Le t t App l M i c rob i o l 4 : 121 -12 4
17. Ne idhardt FC, Bloch PL, S mi th D F 1974) Cul ture mediu m for ente robac te r ia . J Bac te r io l
119 : 736-747
18. Ros zak DB , C olw el l RR 1987) Surviv a l s t ra tegies of bac te r ia in the na tural envi ronm ent .
M i c r o b i o l R e v 5 1 : 3 6 5 - 3 7 9
19. S iege le D A , Kol te r R 1992) Li fe a f te r log . J Bac te r io l 174:345-34 8
20 . To rm o A, Al m i ron M , Ko l t e r R 1990) s u r A an E s ch er i ch i a co I i gene essent ia l for surviva l in
s ta tionary phase . J Bac te r io l 17 2:4339-434 7