Ribeirão Preto, September 2011 - nº 21 Year 11

CTC EDUCATIONAL PROJECTMEDICAL SCHOOL OF RIBEIRÃO PRETO

REGIONAL BLOOD CENTER OF RIBEIRÃO PRETO

In 1897, Carlos Chagas (1878-1934) left the coffee farm where he was born in Minas Gerais, near a small town named Oliveira, and enrolled himself in the Faculdade de Medicina do Rio de Janeiro that back then was the capital of Brazil.

His conclusion thesis was completely dedicated to study malaria. After he majored, Chagas was assigned by Oswaldo Cruz to fight the malaria epidemics that have jeopardized the modernization works in the country.

Men who worked in the expansion of the railroad Central do Brasil were getting sick, halting the construction. It was right there that Carlos Chagas, after 30 years, discovered what he is famous for.

Carlos Chagas´ history

Raising laughs from the audience, Ádamo Siena and Daniele Viola showed how the sanitarist physician Carlos Chagas was the first scientist to completely describe an infectious disease. The play, written and performed by them, shows how the

kissing bug – that is how is called the insect Triatoma infestans – transmits the Trypanossoma cruzi,

flagellate protozoan, responsible for

Chagas’ disease. The play

premiere “Chagas and the kissing

bug” took place in February 2010, when the House of Science

received

students from the discontinued program “Me at USP Jr.” by the Dean for Cultural and Extramural Activities of the University that aimed to offer Elementary and High School students experience with the scientific and cultural atmosphere of USP.

To write the play, Ádamo and Daniele - former students of the House of Science and undergraduate in Biological Sciences (Unesp) and Physical Education (USP), respectively –adopted as reference the celebration edition of the 100 hundred years of the discovery of Chagas’ disease by Revista Radis, produced by Fundação Fiocruz (Fundação Oswaldo Cruz). The discovery of the disease was in 1909, when Carlos Chagas went to Minas Gerais to help in the campaign against malaria.

The theatre production illustrates how the bug infects human beings: it is

generally at night and in the face area where the kissing bug (that is the reason for its name), sometimes infected by T. cruzi, bites man to suck blood and then they fill up their digestive tube and defecate close to the bitten area. By scratching this area, man makes easier the entrance of the parasite in the organism, once the parasite might stay in the bug’s feces. The House of the Science – supported by the Regional Blood Center of Ribeirão Preto – produced a video based on the play which is available on the website www.hemocentro.fmrp.usp.br/casadaciencia

The flight of bees in life reproduction

Life in the root of water hyacinth

DNA scrap

p. 5p. 3 p. 6

Ribeirão Preto, September 2011- nº 21 Year 11 2

The Journal of Sciences is a publication of the House of Science of the Regional Blood Center of Ribeirão Preto/USP distributed to schools. It is part of the Educational Project CTC/CEPID and INCTC – Fapesp and CNPq. Coordinators: Dimas Tadeu Covas, Marco Antonio Zago and Marisa Ramos Barbieri. Coordinator of the House of Science and MuLEC: Marisa Ramos Barbieri. Journalist: Gisele S. Oliveira – MTB 61.339. Layout: Gisele S. Oliveira. Articles: the House of Science team: Ádamo D. D. Siena, André Perticarrari, Fernando Trigo, Gisele S. Oliveira, Gustavo Leopoldo R. Daré, Maria José de Souza G. Vechia, Marisa Ramos Barbieri, Ricardo M. Couto and Rosimeire R. Tritola. Translation and Revision: Alessandra Almeida and Fernanda Udinal. Support: Blood Center of Ribeirão Preto Foundation, Fapesp, CNPq and USP. Address: Tenente Catão Roxo Street, 2501, CEP 14051-140. Telephone: +55 16 2101 9308. Website: www.hemocentro.fmrp.usp.br/casadaciencia. E-mail: casadaciencia@hemocentro.fmrp.usp.br. Circulation: 3.500 copies. Free distribution. The material reproduction is allowed unless the source is mentioned.

Editorial

Interview The use of Trypanossoma cruzi in scientific research

The infection by T. cruzi results in a series of diseases, for example, heart disease, megaesophagus, megacolon. A question that intrigues researchers is how this flagellate modulates the immune response. “If we were able to answer this question, we would also be able to answer how the immune system works. We are using T. cruzi as a weapon to answer this question and, by indirect means; we ended up answering how the infection triggers these diseases”, he reveals. This flagellate has the capacity to infect all nucleated cells and it has a series of surface molecules that interact with the cell molecules. “This interaction happens due to many parasites’ receptors which bind with the host cell and then the parasite effectively enters”, Prof. João explains. Read the interview:

not infect. JS - When is exactly T. cruzi

identified in exams? I do not look for the parasite; I look for

its consequences. I check if there is any antibody against T. cruzi in the individual’s serum, consisting in an indirect assay. I can do a direct assay though: I get the individual’s blood and run a PCR to check if T. cruzi is there. Years ago, we used to conduct an assay known as xenodiagnoses, we used to place 40 kissing bugs in the individual’s arm and engorged, and we waited for 40 days and then analyzed the bug’s feces to check if it was infected. It was an assay to identify the parasite.

JS - Why is not the immune system able to fight T. cruzi?

Actually the immune system can fight T. cruzi. We have in our lab at least 60 mice from different lines, each one of them has a deficiency in the immune system in some specific points. If I infect one animal that does not present one of these cytokines – which is capable of helping in the infection control – the animal dies in 10 or 12 days. There is a series of molecules that are secreted by the immune system which are involved in the infection control, if the animal does not have it, the animal dies. The immune system is capable of fighting it, but not of eliminating it, that is the difference. Because the encysted parasite moves to determined places and stays within the cell, where the immune system is not able to find it. T. cruzi is capable of getting way from the immune response; it has a series of mechanisms to trick the immune system for a while.

JS - Is there only one type of T. cruzi?There are more than six types of

different strains and even in a type there are several lines. There are some that are extremely pathogenic; they are capable of killing a dog. Sometimes, if I infect a mouse with two T. cruzi, it dies, but there are some that are infected with a million and they just do not die.

JS - In which stage does T. cruzi remain longer in man?

When man is infected, T. cruzi is in the tripomastigote stage, and then it turns to the amastigote stage. T. cruzi remains longer in this encysted stage, which is the amastigote,

because it is “hiding” from the immune response.

JS - What are the perspectives on the cure for the disease or

even on the better understanding of T. cruzi?

There are lots of groups in Brazil and also abroad that have been working to control the disease. Some, like my group, in the past, wanted to know how the disease happens and why the individual gets sick. Today we are quite sure about how the disease develops but not so sure about the effective way to cure it though. There is a drug, benznidazole, which kills the parasite, but has a large number of side effects. We described, two or three years ago, that there are other drugs which are more effective and capable of controlling the parasite in an experimental model. We need an effort to take it from the lab benches to drugstores. It is a quite long way, it involves a lot of people, a lot of money, a lot of effort, because we have to do all the clinical assays and it takes a while. Right now, here in Brazil, we do not receive incentive to do that with T. cruzi.

Do have any doubts? Check more of this interview with Prof. João Santana on the House of Science’s website.www.hemocentro.fmrp.usp.br/casadaciencia

PCR (Polymerase Chain Reaction): is a molecular assay that amplifies DNA sequences specific to the target-pathogen based on temperature variation and use of synthetic oligonucleotides - acid polymer nucleic short, normally with twenty or less bases (source: Fiocruz).

Prof. João Santana coordinates a laboratory at FMRP that has conducted researches on T. cruzi for more than 50 years.

House of Science

Trypanossoma cruzi (T. cruzi) is a flagellate protozoan that causes Chagas’ disease. This name was given by Carlos Chagas in honor of Osvaldo Cruz. Flagellates are unicellular microorganisms that move using flagella, appendices in filament forms. Since the discovery by Chagas, who was indicated to Nobel Price, the studies have never stopped.

The current research with Trypanossoma cruzi goes beyond Chagas’ disease and uses the parasite as a model to observe the response of the immune system. That is what reveals Professor Dr. João Santana da

Silva of the Department of Biochemistry and Immunology of FMRP – USP.

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This 21st edition has a special flavor: the House of Science is celebrating its 10th anniversary. With a long time on the road, the Journal of Sciences (JS) has already a clear editorial line, dedicated to science dissemination with objective texts that privilege the development of concepts, once subjects related to

science are difficult. That is exactly what makes this challenge even better.

All the JS editions are planned and previously structured. However, this edition has revealed how important are the registers done by the team. They are indispensable to write the history of the House of Science, because the production of material for diffusion (website, journal, and Leaflets) is always based on the

evaluation of the coordinated programs.The 21st JS was born from the effort

of the House of Science team to show everybody a small part of the total activities we develop here. However, the menu varies from T. cruzi, DNA, trophic guilds to the root of the water hyacinth.

Enjoy the reading!

Journal of Science: Does Trypanossoma cruzi depend on man for its cycle?

João Santana: It needs any nucleated cell. In the host (man), it invades a cell and there it changes its stage to metacyclic trypomastigotes, if the parasite has come from the kissing bug, for example. Still within the cell, it changes to the amastigote stage and by binary division it multiplies. When the cell gets bigger, with a high amount of parasite, it changes to trypomastigote stage, ruptures the cell and releases a large amount of parasites there which might infect some neighbor cells or if these parasites reach the bloodstream, they might infect distant cells. Then it closes the cycle. If there is kissing bug, the bug sucks blood with the metacyclic trypomastigote stage which, within the bug, goes through a stage known as epimastigote. It does not multiply as epimastigote and when it goes to the digestive tube it changes to metacyclic trypomastigote. Then in the bug’s feces we find metacyclic trypomastigote, which would be the infector stage. If we put a T. cruzi in a liquid, it will turn into epimatisgote. We have a lot of means to culture the parasite as epimastigote, this lower infecting stage. Sometimes it is even used as a “vaccine” in some animals, once it is theoretically the stage that does

The immune system is capable of fighting it, but not of eliminating it, that is the difference. Because

the encysted parasite moves to determined

places and stays within the cell, where the

immune system is not able to find it.

Ribeirão Preto, September 2011 - nº 21 Year 11 3

Who would say that a construction of a DNA model could contribute to the discussion and the development of some concepts! Using materials that would be thrown away, three students from basic education, advised by researchers at the Regional Blood Center (Kátia Kaori Otaguri, Mariana Tomazini Pinto and Tathiane Maistro Malta Pereira) have built a “giant” DNA molecule. This 2m model allowed the students to learn and also explain

DNA scrapthe molecular structure of the DNA to friends who have also explored this subject.

During the presentation, questions like “Why are the strands intertwined in a spiral shape of a helix?” And the students shared what they have learned:

“The double helix, in fact, is not a stair! It is a helix because of the structure, the way they stick with the carbon towards the phosphate, it leans

so the strand rolls up, and the other strand runs in the opposite direction”.

By the register of the House of Science’s team (André Perticarrari, Fernando R. Trigo, Flávia F. do Prado, Maria José de Souza G. Vechia and Renata Aparecida P. Oliveira), the Mural was documented, analyzed, and written so readers, like you, could learn a bit more about this fascinating molecule of life. Check some of the students’ comments:

The DNA is a molecule found within the nucleus of cells. It is formed by a sequence of nucleotides.

Gene is nothing more than a DNA fragment (…), it is a fundamental unit of heredity, it means, it goes from generation to generation. They are formed by specific sequences of nucleic acids.

There are purine and pyrimidine nitrogenous bases and one completes the

other. A pyrimidine completes a purine (…), an adenine completes a thymine and the

cytosine completes the guanine.For a carbon bond to happen it is necessary that carbon 1 is bound to the nitrogenous base, carbon 5 is bound to phosphate of the own nucleotide and the carbon 3 bonds to the phosphate of the next nucleotide. And if we pay attention to this molecule, it is in the direction 5’ by one side and by the other 3’, allowing then to form the bond of the nitrogenous bases.

At the Mural, 42 students discussed and explored more complex subjects like Okazaki’s mysterious fragments, which are synthetized in “small blocks” and then united to form one of the DNA strands; the PCR “thermal shocks” technique to amplify a DNA sample; the enzymes involved in the duplication of the genetic material (DNA polymerase and DNA ligase) and the circularity of bacterial DNA. It was a veritable learning test.

The Mural represents an afternoon fulfilled with very important presentations, in which the students, who take part in

the program “Adopt a Scientist”, have the opportunity to share the outcomes achieved with everybody. A moment of growing together. A total of nine theme groups showed their projects on subjects as Synapse and Neurons, Schizophrenia, Aphasia, Mental Health, DNA Structure, Computer

Biomolecular Science, Drosophila, Biodiversity, Biological Models, Natural Selection, Stem Cells, Cell Differentiation, Blood and Donation (in the play “For one drop”), the projects were evaluated by researchers and teachers.

According to the House of Science’s coordinator, Marisa Ramos Barbieri “the Mural has not ended; it is always a preparation for the next. It has no end, just like the research”. Watching the other groups’ outcomes accelerates the process. The exchange is essential for the rhythm of the program. “It is an opportunity to talk and to listen to everybody”.

When fecundation happens, you “get” a part of the DNA from the father and one from the

mother and everyone here is different because of that. You put different things together and they

form a new sequence. It won’t be like the father or the mother, it’ll be the combination of both.

That’s why people have different characteristics.

The nucleotide is composed by a pentose, a phosphate and

four nitrogenous bases which are adenine, cytosine, guanine, and

thymine.

Ribeirão Preto, September 2011 - nº 21 Year 11 4

From nature to the book or from the book to nature?In “Vacation with Science”, after

exploring the water hyacinth, some students were invited to know a new set of organisms common in the lake of USP, but uncommon in books, the microcrustaceans. When asked about the structures found in the dorsum of the water flea (picture on the left), the students did not dare to say, ask, and recognize the eggs.

But before that, they had the opportunity to participate in the analysis of the diversity of the beings that live in the root of the water hyacinth, to watch a flatworm, a mosquito larvae and a mollusk interacting with nature. It was a great surprise to check the amount of organisms and their sizes, from the microscopic ones to the largest ones (visible

to the naked eye), which can be found coexisting in a 30cm plant. It aroused the curiosity and the will to separately recognize and identify the different beings in that microenvironment.Pa

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Daphnia sp.

Student observing the root of the water hyacinth during “Vacation with Science”.

House of Science

Are the animals of the water hyacinth, as the water flea, the same as those in the books? And the doubt was raised.

What are stem cells?They are special cells capable

of originating other cells of the body and also of self-renewing. They are unique, because they can remain undifferentiated or originate specialized cells by cell differentiation.

Stem cells can be embryonic or adult and can be classified according to the number of the different cell lines they are able to originate.

Embryonic stem cells are found in embryos, the ones isolated, before the blastocyst stage, are totipotent and they can originate all embryonic and extra-embryonic (placenta and annex) cells. The stem cells isolated at blastocyst stage though are pluripotent and able to originate all kind of embryo cells.

The adults are found in diverse tissues such as bone marrow and liver. This type of stem cell has a more limited differentiation capacity; they are multipotent and able to generate cells from different lines.

Why does cell differentiation happen in stem cells?

This special feature of stem cells of generating a differentiated cell happens because of the asymmetric mitosis. For a long time mitosis has been defined as a cell division in two exactly the same. However with all advancements in cell biology, a “new type of

mitosis” has been defined: the asymmetric (the one the stem cells perform), in which the cells replicate and differentiate. By doing the asymmetric mitosis, the cell originates a copy of itself that keeps the original features, primary or stem (and then the name stem cells) and also originates a differentiated cell.

Despite different, the cells keep the same genetic material of the first cell that has originated them. The difference is in the activation and inhibition of specific groups of genes that will determine the function and the structure of every cell.

What are the importance and the objective of the studies on stem cells?

The study of these cells is extremely important, because scientists suspect that on these cells relies the key for the cure of many diseases, such as cardiovascular diseases, neurodegenerative, type 1 diabetes, strokes, blood disorders, spinal cord injuries, and kidney diseases. The main goal of the researches on stem cells is to use them to recover tissues damaged by these diseases or injuries. A good example is the bone marrow transplant, a therapy with adult stem cells, an extensively investigated subject that can cure blood

diseases, such as leukemia. Are stem cells exclusive to

humans?Stem cells are not only found in

humans, they can also be found in plants and in all multicellular organisms, however the potency of the adult stem cells varies depending on the organism.

Written by the student Luciana Souza da Silva, from the public

school Professor Nestor Gomes de Araújo from Dumont – SP.

Stem cells and asymmetric division

House of Science

Luciana during her presentation at the Mural in December 2010.

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Ribeirão Preto, September 2011 - nº 21 Year 11 5

The flight of bees in the reproduction of lifeFlying is a wish of every human

being. From angels to Superman, seeing the world from the top arouses curiosity and sparks our imagination. Who has never thought of flying? There is only a problem though: it requires energy. The animals worked this out by many different ways, by making their skeleton lighter, like the birds did, or specializing their food, like bees did.

Bees are expert on the art of flying, but how and where they get energy for that?

Of course flowers are gorgeous, with their forms and colors that delight those who can see. But those who see it from the top see it better, and they not only enjoy the view, they also search for the food hidden within the flowers. It is the

How many organisms benefit from this flower

(Tecoma stans)? We would be naïve if we thought

that this flower fulfills the needs of only one species of bee. Actually, Tecoma stans is a tree that can reach 12 meters, native to Mexico and brought to Brazil in 1871, it might be useful to 48 species of bees, among them the native of the Xylocopa

gender, popularly known as mangava or mamangava.

In the lack of this plant, or when it is in flowering, the bees attracted by the flowers of Tecoma explore other species, like the passion fruit (Passiflora sp) and the orange tree (Citrus sp).

Trophic guilds Organism is a common reference

in the studies of extinct and living beings, however there is a discussion about the limitations of using it, which has made difficult the understanding of biodiversity, whose complexity is not fully explored. Studying the organism is important, but is it enough to

understand the specific and complex questions related to population and community?

A concept not fully explored, but fundamental for

understanding the energy flow in an ecosystem, is the concept of the

trophic guilds, which are formed by species that explore, in a similar way, a common base of resources (food). We can have, for example,

To analyze and investigateIn a sugar cane monoculture,

what happens to the guilds? It is expected a decrease of the

biodiversity, with a reduction of the natural vegetation, getting rid of the native vegetation to plant a single species of plant reducing the number of ecologic guilds!

Getting to school…Knowing the food

specialization of bees was important for the students at the 8th grade of the school Sesi 259 in Ribeirão Preto, supervised by the teacher Ricardo Couto and the journalist Danielle Castro in an investigative work for the specialization course “Partners in Science Dissemination” (2010 – 2011), coordinated by the House of Science.

Bee that emerged from a nest located in the trunk of Tecoma stans at the school Sesi.

Ricardo M. Couto

Mangava bee visiting inflorescence of Tecoma stans

nectar which is composed by sugars, an important source of energy.

Flying also allows bees to visit more than one thousand flowers a day. It is quite a nice life, isn’t it? They enjoy the lovely views, eat and then they just have to find the “perfect” match to reproduce. As incredible as it may seem, flowers also help on that happy history of life!

Flowers produce the pollen grain, a food rich in

proteins, which is extracted and transported, in the third pair of

legs, up to the nest. Why do bees set down pollen in their nest?

The female “just like our moms” take care of their children. This mother care starts when the larvae breaks through the egg and starts being fed with the pollen brought by the females.

House of Science

Tongue or glossa of a bee (Apinae: Euglossini) adapted to collect nectar from flowers.

the guild of nectar collectors or the guild of pollen collectors.

There are many reasons for the bees to visit flowers and diverse ways by which flowers attract bees, forming different guilds and resulting in a diversity of interaction between both. Flowers provide food (pollen, nectar, and oil), produce substances used by bees in the construction of the nest or needed for the bees’ reproduction, hide floral resources, deceive the visitors or serve as a place for mating. For curious observers and bee researchers it is possible to notice that the behavior and the form are specialized for the collector resources difficult to access and for exploring specific floral resources. These pollinator guilds are formed mostly by species of lonesome bees, in which there is no contact among generations, because generally the female dies before the descendants emerge.

Studying population and community goes beyond knowing a catalogue of species or describing ecological relationships. Has media, with its important role in scientific dissemination and in being opinion leader, found sources that might be the foundation for the complex network of knowledge that compose the subject of biodiversity?

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Ribeirão Preto, September 2011 - nº 21 Year 11 6

Life in the root of a water hyacinth In July 2010, in one edition of

“Vacation with Science”, a program by the House of Science for students from basic education, the subject was the biodiversity in the lake of USP. Once these programs are developed in the MuLEC – Museum and Laboratory for Science Teaching - located at the campus of USP, they aim to articulate the relation between laboratory and nature observation, followed by theoretical

discussions with specialists. For three days, the students’ participation in various activities such as experiments, lectures, and observation is documented and

allow us to notice the enthusiasm in confirming the information read on books and textbooks.

Focusing on zooplankton, in this activity, guided by André Perticarrari (expert on aquatic ecosystems), the students observed and analyzed

a plant present in the lake, the water hyacinth that was collected the day before. With the idea of working

with diversity of the beings that live in this

plant, understanding a little more about the organisms found, the students were invited to explore it. They

observed the animals and tried to recognize the different groups – their

forms and behaviors, associating it with what they have learned at school.

Do you know the water hyacinth?

The water hyacinth is a plant common to aquatic environments, floating on the surface with the help of “natural floats”, it means, the base of the leaves is dilated and rich in a tissue that accumulates air (aerenchyma), it belongs to the group of the angiosperms, produces flowers and fruits. But what is the relation between diversity and this plant?

Many living beings roots can be watched living in its roots where they find shelter from predators, find food resources, a place for reproduction, forming a microenvironment. Odonata

A complex “ecosystem”This great diversity of living

beings, belonging to many groups and found in the root of the water hyacinth, forms a real community where a lot of interactions happen. There the microorganisms find shelter against predators, but they also find food. Mites, which are voracious predators, eat mosquito larvae which by their turn eat the small microcrustaceans. Small fish eat the snails that eat the microscopic algae that adhere to the root. We can notice, by these few examples, different food chains that form a complex food network only in this small environment. Another ecological relation we can find is the presence of microscopic algae, bacteria, protozoan and rotifer that are adhered to the roots, forming what we call periphyton (a group of organisms that adhere to a substrate); this relationship is known as epiphytes.

Today’s special: periphyton!As we have seen, many organisms

adhere to the root of this plant. These living beings represent a true banquet to a lot of animals that form the trophic guild of the epiphytes or periphyton eaters. A guild is formed by groups of organisms that have similar ways of surviving, it means, they explore the same resources in a similar way. In our case, animals that eat periphyton. Plenty of insects, such as the ephemeroptera nymph and the mosquito larvae, various fish, little mollusks, and tadpoles belong to this guild, eating the microalgae, rotifer and protozoan from the roots, exploring this rich food resource.

As we can see, a simple plant that floats on aquatic environments might be a place where many ecological relationships happen and a lot of animals find food to survive. If a plant gives shelter to huge

Learn more!Do you want to know more about

flatworms, zooplankton, and ecosystems? Visit the House of Science website: www.hemocentro.fmrp.usp.br/casadaciencia

nymphs (dragonflies) and other insects, gastropod mollusk, mosquito larvae, water mites, flatworms, microcrustaceans (cladocerans or water fleas and copepods, that compose zooplankton), notonectas (backswimmers) rotifera (microscopic animals), tadpoles and even fish can be found (see the scheme). These beings found can be microscopic (about 100 to 1000 times smaller than a millimeter) and some with many centimeters living together. Environmental factors such as water condition, light, food, temperature, etc., may vary over the years, influencing in the diversity.

Investigating the biodiversity: student observes root of water hyacinth for SNCT / CNPq - 2010.

Descending order

Check the size of animals in a scale

diversity, could you imagine a lake?The outcomes of these activities have

awakened interest and gave birth to an exposition about diversity and stem cells in the lake of USP (in the National Week of Science and Technology by CNPq – 2010). Think and answer

Can animals that eat plankton (phyto and zooplankton) form a guild? And the ones that eat detritus (rests of organisms, organic matter)?

Would you know the relation between guild and diversity? Could the guild be a diversity indicator?

Water hyacinth and its fauna

House of Science