Determinação de motivos de ligação à quitina em vicilinas de Canavalia ensiformis e Vigna unguiculata através de métodos in silico e relação com suas toxicidades para o bruquídeo Callosobruchus maculatus (Coleoptera:Bruchidae)

Chitin is an important structural component of the cellular wall of fungi and exoskeleton of many invertebrate plagues, such as insects and nematodes. In digestory systems of insects it forms a named matrix of peritrophic membrane. One of the most studied interaction models protein-carbohydrate is the model that involves chitin-binding proteins. Among the involved characterized domains already in this interaction if they detach the hevein domain (HD), from of Hevea brasiliensis (Rubber tree), the R&R consensus domain (R&R), found in cuticular proteins of insects, and the motif called in this study as conglicinin motif (CD), found in the cristallography structure of the β-conglicinin bounded with GlcNac. These three chitin-binding domains had been used to determine which of them could be involved in silico in the interaction of Canavalia ensiformis and Vigna unguiculata vicilins with chitin, as well as associate these results with the WD50 of these vicilins for Callosobruchus maculatus larvae. The technique of comparative modeling was used for construction of the model 3D of the vicilin of V. unguiculata, that was not found in the data bases. Using the ClustalW program it was gotten localization of these domains in the vicilins primary structure. The domains R&R and CD had been found with bigger homology in the vicilins primary sequences and had been target of interaction studies. Through program GRAMM models of interaction ( dockings ) of the vicilins with GlcNac had been gotten. The results had shown that, through analysis in silico, HD is not part of the vicilins structures, proving the result gotten with the alignment of the primary sequences; the R&R domain, although not to have structural similarity in the vicilins, probably it has a participation in the activity of interaction of these with GlcNac; whereas the CD domain participates directly in the interaction of the vicilins with GlcNac. These results in silico show that the amino acid number, the types and the amount of binding made for the CD motif with GlcNac seem to be directly associates to the deleterious power that these vicilins show for C. maculatus larvae. This can give an initial step in the briefing of as the vicilins interact with alive chitin in and exert its toxic power for insects that possess peritrophic membrane

Determinação de motivos de ligação à quitina em vicilinas de Canavalia ensiformis e Vigna unguiculata através de métodos in silico e relação com suas toxicidades para o bruquídeo Callosobruchus maculatus (Coleoptera:Bruchidae)

Chitin is an important structural component of the cellular wall of fungi and exoskeleton of many invertebrate plagues, such as insects and nematodes. In digestory systems of insects it forms a named matrix of peritrophic membrane. One of the most studied interaction models protein-carbohydrate is the model that involves chitin-binding proteins. Among the involved characterized domains already in this interaction if they detach the hevein domain (HD), from of Hevea brasiliensis (Rubber tree), the R&R consensus domain (R&R), found in cuticular proteins of insects, and the motif called in this study as conglicinin motif (CD), found in the cristallography structure of the β-conglicinin bounded with GlcNac. These three chitin-binding domains had been used to determine which of them could be involved in silico in the interaction of Canavalia ensiformis and Vigna unguiculata vicilins with chitin, as well as associate these results with the WD50 of these vicilins for Callosobruchus maculatus larvae. The technique of comparative modeling was used for construction of the model 3D of the vicilin of V. unguiculata, that was not found in the data bases. Using the ClustalW program it was gotten localization of these domains in the vicilins primary structure. The domains R&R and CD had been found with bigger homology in the vicilins primary sequences and had been target of interaction studies. Through program GRAMM models of interaction ( dockings ) of the vicilins with GlcNac had been gotten. The results had shown that, through analysis in silico, HD is not part of the vicilins structures, proving the result gotten with the alignment of the primary sequences; the R&R domain, although not to have structural similarity in the vicilins, probably it has a participation in the activity of interaction of these with GlcNac; whereas the CD domain participates directly in the interaction of the vicilins with GlcNac. These results in silico show that the amino acid number, the types and the amount of binding made for the CD motif with GlcNac seem to be directly associates to the deleterious power that these vicilins show for C. maculatus larvae. This can give an initial step in the briefing of as the vicilins interact with alive chitin in and exert its toxic power for insects that possess peritrophic membrane

Influência dos fatores abióticos sobre a variação espaço-temporal de paralonchurus brasiliensis (Steindachner, 1875) (pisces, sciaenidae) componente da fauna acompanhante da pesca de camarões no litoral Norte de São Paulo

Knowledge of the environmental factors influence on the spatial-temporal variation of fishes is important to fisheries management and conservation. Thus, the aim of this work was to analyze the influence of the abiotical factors on the spatial-temporal distribution of Paralonchurus brasiliensis (Pisces, Sciaenidae) caught by-catch with the shrimp fishing of Ubatuba and Caraguatatuba regions, north coast of São Paulo State. The fishes were captured every month from January to December 2002. Samples were collected by otter trawl at 5, 10, 15, 20, 25, 30 and 35m depths. The temperatures (surface and bottom), salinities (surface and bottom), sediment features and organic matters were verified for each depth. During all period of the study 12.642 specimens of P. brasiliensis were captured at Ubatuba and 17.166 at Caraguatatuba, which totalized the biomass of 267 for the first and 339kg for the other region. The females outnumbered males in fish population. The greatest values of biomass and number of individuals were registered at the summer and autumn seasons, while the lowest values were observed at the winter and spring seasons. The greatest abundances were found from 15 to 25m depth. In this study, it was verified that P. brasiliensis is a coastal waters associate species. The spatialtemporal distribution of P. brasiliensis is affected by intrusion of SACW and depth for the coastal region and by depth and sediment in sheltered areas such as Caraguatatuba

Caracterização e quantificação de marcadores químicos do extrato hidroetanólico das folhas de Kalanchoe brasiliensis Cambess

Kalanchoe brasiliensis Cambess (Crassulaceae), commonly known as saião , coirama branca , folha grossa , is originally from Brazil and commonly found in São Paulo to Bahia, mainly in the coastal zone. Regarding of biological activities, most preclinical studies were found in the literature, mainly about the anti-inflammatory activity of extracts obtained from leaves and / or aerial parts of K. brasiliensis. As regards the chemical constitution, it has been reported mainly the presence of flavonoids in the leaves of the species, but until this moment did not knows which are the active compounds. Although it is a species widely used in traditional medicine in Brazil, there is no monograph about the quality parameters of the plant drug. In this context, this study aims to characterize and quantify the chemical markers of hydroethanolic extract (HE) from the leaves of K. brasiliensis, which can be used in quality control of plant drug and derivatives obtained from this species. The methodology was divided into two parts: i. Phytochemical study: to fractionate, isolate and characterizate of the chemical (s) marker (s) of the HE from the leaves of K. brasiliensis; ii. To Developed validate of analytical method by High Performance Liquid Chromatography (HPLC)-diode array detector (DAD) to quantify the chemical (s) marker (s) of the EH. i. The EH 50% was prepared by turbo extraction method. It was then submitted to liquid-liquid partition, obtaining dichloromethane, n-butanol and ethyl acetate (AcOEt) fractions. The AcOEt fraction was selected to continue the fractionation process, because it has a chemical profile rich in flavonoids. The acOEt fraction was submitted to column chromatography using different systems for obtaining the compound Kb1. To identify this compound, it was submitted to UV analysis ii. For quantitative analysis, the EH was analyzed by HPLC, using different methods. After selecting the most appropriate method, which showed satisfactory resolution and symmetrical peaks, it was validated according to parameters in the RE 899/2003. As result, it was obtained from the AcOEt fraction the compound Kb1 (2.7 mg). Until this moment, the basic nucleus was characterized by UV analysis using shift reagents. The partial chemical structure of the compound Kb1 was identified as a flavonol, containing hydroxyls in 3 , 4 position (ring A), 5 and 7 free (ring B) and a replacement of the C3 hydroxyl by a sugar. As the analysis were performed in the HPLC coupled to a DAD, we observed that the UV spectrum of the major peaks of EH from K. brasiliensis shown similar UV spectrum. According to the literature, it has been reported the presence of patuletin glycosydes derivatives in the leaves of this species. Therefore, it is suggested that the compound Kb1 is glycosylated patuletin derivative. Probably the sugar (s) unit(s) are linked in the C3 in the C ring. . Regarding the development of HPLC analytical method, the system used consists of phase A: water: formic acid (99,7:0,3, v / v) and phase B: methanol: formic acid (99,7:0,3, v / v), elution gradient of 40% B - 58% B in 50 minutes, ccolumn (Hichrom ®) C18 (250x4, 0 mm, 5 μm), flow rate 0.8 mL / min, UV detection at 370 nm, temperature 25 ° C. In the analysis performed with the co-injection of thecompound Kb1 + HE of K. brasiliensis was observed that it is one of the major compounds with a retention time of 12.47 minutes and had a content of 15.3% in EH of leaves from K. brasiliensis. The method proved to be linear, precise, accurate and reproducible. According to these results, it was observed that compound Kb1 can be used as a chemical marker of EH from leaves of K. brasiliensis, to assist in quality control of drug plant and its derivatives

Dinâmica de reprodução e comportamento reprodutivo de branchoneta Dendrocephalus brasiliensis Pesata, 1921 como incremento na produção de alimento vivo para peixes ornamentais

Reproductive behavior of Dendrocephalus brasiliensis Pesta, 1921(Crustacean: Anostracan). The reproductive behavior of fresh water Anostracan has been poorly investigated in carcinology specialized literature, specifically in relation to Dendrocephlaus brasiliensis Pesta, 1921, with abundant data just about the geographical distribution of that Anostracan. The objective of this work was to know the reproductive behavior of this Anostracan, in different seasons (dry and raine). For this, ripe individuals of both sexes were collected in four pond of the of Fish farming Station of Paulo Afonso (EPPA), through monthly captures in each ponds, from December 2004 to November 2005. The type of reproduction was observed after the placing in aquariums (a) of then with males and (b) other on individually, at the nauplii phase, where they stayed for 15 days until the reproductive age. The sexual proportion was calculated through the relative frequencies of males and females, every month, for the whole collection period during 10 days. the production of cysts was related to the size of the female. The male: female ratio in the study period was 1 male:1,07 female. The proportion male:female was from 48,25% : 51,75% along the year. Concerning the type of reproduction, it was observed that this specie is characteerized by sexual reproduction

Estratégia reprodutiva do peixe-voador, Hirundichthys affinis e do peixe agulha preta, Hemiramphus brasiliensis no litoral de Caiçara do Norte, Rio Grande do Norte, Brasil

The flyingfish, Hirundichthys affinis (Günther, 1866) (Exocoetidae) and ballyhoo half beak, Hemiramphus brasiliensis (Linnaeus, 1758) (Hemiramphidae) are marine fish species of commercial value, which contribute to artisanal fishery production of Rio Grande do Norte, Brazil. Besides the economic importance, these fish are important from an ecological point of view, being components in pelagic food chain, where they are the preferred prey of larger predators of high commercial value. This study aimed to determine the reproductive strategies of H. affinis and H. brasiliensis and the fishery production of H. affinis in the northern coast of Rio Grande do Norte. The results are presented in the form of six cientific articles and a review paper. The first article presents the morphometric measurements and meristic counts which confirmed the taxonomic status, population structure in length-weight and the gonad development of H. affinis through macroscopic observations of the ovaries and testes. Females of this species were bigger and heavier than males. The second article describes the reproductive tactics, such as, sex ratio, length at first sexual maturity, histological aspects of gonads, fecundity and spawning season, that indicate the reproductive strategy of H. affinis. The third article shows annual changes in the fishery production of H. affinis in Caiçara do Norte, during the period of 1993 to 2010, emphasizing the relevance of this fish in total fishery production of Rio Grande do Norte, besides registering the fall in production in the years 2008 to 2010. The fourth article describes the population structure, with respect to the length and weight, the length-weight relationship, growth type and sex ratio of Hemiramphus brasiliensis. The fifth article describes the reproductive biology of H. brasiliensis, with details about sex ratio, length at first sexual maturity, fecundity, type of breeding and spawning season. The sixth article deals with the reproductive strategy of H. brasiliensis. The review paper presents the topic of age determination of tropical fish using analysis of otoliths. Both species use the coastal waters of Caiçara do Norte for reproductive purposes. The flying fish, H. affinis migrates from the oceanic waters to the coastal waters to reproduce, coinciding with the rainy season. H. affinis presents total spawning and a seasonal reproductive strategy. However, H. brasiliensis lives and reproduces in the coastal waters displaying partial spawning and an equilibrium reproductive strategy

Determinação de Ba, Cd, Cr, Cu, Ni, Pb, Sn e Zn em Tainha (Mugil brasiliensis) nos estuários potiguares

Heavy metals can cause problems of human poisoning by ingestion of contaminated food, and the environment, a negative impact on the aquatic fauna and flora. And for the presence of these metals have been used for aquatic animals biomonitoramento environment. This research was done in order to assess the environmental impact of industrial and domestic sewage dumped in estuaries potiguares, from measures of heavy metals in mullet. The methods used for these determinations are those in the literature for analysis of food and water. Collections were 20 samples of mullet in several municipality of the state of Rio Grande do Norte, from the estuaries potiguares. Were analyzed the content of humidity, ash and heavy metals. The data were subjected to two methods of exploratory analysis: analysis of the main components (PCA), which provided a multivariate interpretation, showing that the samples are grouped according to similarities in the levels of metals and analysis of hierarchical groupings (HCA), producing similar results. These tests have proved useful for the treatment of the data producing information that would hardly viewed directly in the matrix of data. The analysis of the results shows the high levels of metallic species in samples Mugil brasiliensis collected in Estuaries /Potengi, Piranhas/Açu, Guaraíra / Papeba / Arês and Curimataú

Atividade toxicológica do extrato das folhas de Kalanchoe brasiliensis em camundongos Swiss

The species of the genus Kalanchoe (Crassulaceae) are widely used in Brazil as a medicinal product to treat cough, boils, gastritis and other diseases. In this scenario stands out K. brasiliensis, popularly known as coirama or saião. This paper aims at the oral exposure of mice to a hydroalcoholic extract of leaves of Kalanchoe brasiliensis. The animals (total of 100) were divided into 12 groups (6 males and 6 females) for the acute assessment; and groups of 10 for subchronic evaluation. Test groups were treated with doses of 250 mg / kg, 500 mg / kg, 1000 mg / kg and 2000 mg / kg and the control group received 0.9% saline. The animals were observed for 14 days for acute evaluation and 30 days for subchronic evaluation, and in that period analyzed the appearance of clinical signs, changes in weight and consumption of water and food. After the observation period, histopathological analysis of the organs, biochemical serum and haematological parameters for the assessment of the subchronic groups were processed. Differences and changes in body weight were not observed among the groups, nor consumption of water and food, there were no deaths among the groups in the two types of assays. Histopathological analysis showed some alterations compatible with low acute hepatic toxicity. The results of blood glucose, triglycerides, ALT, urea and creatinine showed differences between the control group and the test concentrations studied (p <0.05), but these differences do not show relevant change in the clinical picture of animals. The results showed that the extract K. brasiliensis has low acute toxicity at the doses used and no toxicity when administered for 30 days. This highlights the importance of this species as future and promising candidate for phytotherapics, so has its pharmacological trials completed.

Influência dos fatores abióticos sobre a variação espaço-temporal de paralonchurus brasiliensis (Steindachner, 1875) (pisces, sciaenidae) componente da fauna acompanhante da pesca de camarões no litoral Norte de São Paulo

Knowledge of the environmental factors influence on the spatial-temporal variation of fishes is important to fisheries management and conservation. Thus, the aim of this work was to analyze the influence of the abiotical factors on the spatial-temporal distribution of Paralonchurus brasiliensis (Pisces, Sciaenidae) caught by-catch with the shrimp fishing of Ubatuba and Caraguatatuba regions, north coast of São Paulo State. The fishes were captured every month from January to December 2002. Samples were collected by otter trawl at 5, 10, 15, 20, 25, 30 and 35m depths. The temperatures (surface and bottom), salinities (surface and bottom), sediment features and organic matters were verified for each depth. During all period of the study 12.642 specimens of P. brasiliensis were captured at Ubatuba and 17.166 at Caraguatatuba, which totalized the biomass of 267 for the first and 339kg for the other region. The females outnumbered males in fish population. The greatest values of biomass and number of individuals were registered at the summer and autumn seasons, while the lowest values were observed at the winter and spring seasons. The greatest abundances were found from 15 to 25m depth. In this study, it was verified that P. brasiliensis is a coastal waters associate species. The spatialtemporal distribution of P. brasiliensis is affected by intrusion of SACW and depth for the coastal region and by depth and sediment in sheltered areas such as Caraguatatuba

Abundância e distribuição sazonal de espécies autóctones de camarões peneídeos no canal de abastecimento do sistema primar de aquicultura orgânica (Laguna de Guaraíras, Tibau do Sul, Rio Grande do Norte, Brasil)

Guaraíras lagoon, located in Tibau do Sul in the eastern littoral of Rio Grande do Norte (Brazil), presents a permanent connection to the sea, which guarantees the occurrence of a rich biodiversity, which includes the autochthonous shrimp species Litopenaeus schmitti, Farfantepenaeus subtilis and Farfantepenaeus brasiliensis. In spite of being subject to a strong human intervention in the last decade, mainly related to the installation of shrimp (Litopenaeus vannamei) farms, the lagoon is still scarcely studied. The present study aims at characterizing the populations of the three autochthonous penaeid shrimp species inhabiting Guaraíras, taking into consideration their abundance and seasonal distribution in the inflow channel of Primar System of Organic Aquaculture (Tibau do Sul, Rio Grande do Norte, Brazil). Twelve monthly samples were carried out from May 2005 to April 2006 with the aid of a circular cast net in the inflow channel, which is daily supplied with water from Guaraíras. Sampling months were grouped in trimesters according to the total pluviosity, thus comprising four trimesters. Water salinity was monitored twice a week and temperature values registered on a daily basis at noon, during the study period. The daily pluviosity data from the municipality of Tibau do Sul were supplied by Empresa de Pesquisa Agropecuária do Rio Grande do Norte (EMPARN). Collected shrimp were identified, weighted, measured and sexed. L. schmitti specimens (0.2 g to 17.8 g) were distributed in 1.3 g weight classes intervals. From the eighth sampling month (December 2005) onwards, males were classified into three categories, in accordance with the development of their petasm: (a) rudimentary petasm, (b) partially formed petasm, and (c) completely formed petasm. Among the ecological variables, rainfall showed the greatest dispersion (s.d.=187.74Rainfall and abundance of L. schmitti were negatively correlated (r = -0.85) whereas its abundance and water salinity were positively correlated (r = 0.63). Among 1,144 collected individuals, 1,127 were L. schmitti, 13 were F. subtilis and 4 were F. brasiliensis, which corresponded to 98.51%, 1.14% and 0.35% of the total of collected individuals. L. schmitti occurred in 100 % of all samples. Differently, the presence of F. subtilis and F. brasiliensis was restricted to 33% and 17% of the collected samples, respectively. The present study confirmed the occurrence of L. schmitti, F. brasiliensis and F. subtilis in Guaraíras. However, this lagoon seems to be primarily inhabited by juvenile Litopenaeus schmitti. The population of L. schmitti analysed showed a seasonal pattern of distribution. In general, in the months of high salinity and absence of rain, the number of individuals was higher than in the wet months. Further studies on the reproductive biology and ecology of L. schmitti, F. brasiliensis and F. subtilis may elucidate questions referring to the abundance, period, and phase of occurrence of these shrimp genera in Guaraíras. Finally, the risks associated to the establishment of L. vannamei in the lagoon provide a novel outlet for studies in this biotope

Efeito inseticida de vicilinas isoladas de sementes de erythrina velutina em condições de semi-campo para moscas das frutas (ceratitis capitata)

Chitin-binding vicilins from legume seeds (Erythrina velutina. Canavalia ensiformes and Phaseolus vulgares) were isolated by ammonium sulfate followed by affinity chromatography on a chitin column. Effect of these vicilins on female adults of Ceratitis capitata was examined by bioassay and in a semi-field assay model. Mechanism of action of the vicilins was determined by in vivo digestibility and chitin affinity. Among the tested vicilins, E. velutina when added to diet caused strong effect on mortality at 10% dose. This insecticidal property was tested in a semi-field assay which showed the same effect observed in laboratory conditions, where doses of 10% and 15% were lethal to female adults of C. capitata. These deleterious effects were not only associated to the binding to chitin structures present in peritrophic membrane, but principally to its low digestibility in the C. capitata digestive tract. This fact was confirmed because chiting binding proteins as WGA and the other tested vicilins were not toxic to female adults of C. capitata due susceptibility of these proteins to digestive enzymes of the insects. By other side EvV was more resistant to digestive enzymes, causing deleterious effects on female adults of C. capitata. These results showed that EvV may be part of the pest management programs or an alternative in plant improvement program in the population control of this fruticulture pest

Avaliação da atividade antimalárica e citotóxica de plantas medicinais dos Biomas Caatinga e Amazônico

Resistance of Plasmodium falciparum to the usual antimalarials, as well as their adverse effects and high cost, has led to the search of new drugs against malaria. Several of these have been developed from medicinal plants based on ethnopharmacology, including the most widely used antimalarials today: quinine and artemisinin. In the present study schizonticide activity of extracts and fractions of a number of medicinal plants from the Caatinga and Amazon biomes were assessed based on ethnopharmacological and chemosystematic information. These included Ximenia americana, Maytenus rigida, Sideroxylon obtusifolium, Stryphnodendro coriaceum, Bowdichia virgiliodes, Schinopis brasiliensis and Picrolemma sprucei, the last, an Amazon species. Antimalarial tests of blood schizonticides were conducted in Swiss mice infected with P. berghei and in vitro against P. falciparum. In vitro cytotoxicity studies were carried out using HeLa, CHO, 3T3, Raw and HEPG2 cell lines. Except for X. americana, all species exhibited in vivo or in vitro antimalarial activity, inhibiting parasitic growth by up to 79%. Extracts exhibited moderate toxicity with dosedependent kinetics. In this sense, ethnopharmacological and chemosystematic approaches were shown to be useful and promising tools in the search of new drugs. These findings represent a significant contribution to scientific knowledge of the antimalarial potential of Brazilian flora, thereby opening perspectives for the development of new antimalarials

Soroprevalência da infecção pelo Trypanosoma cruzi no município de Caicó, RN, e caracterização genética por RAPD do parasito isolado de humanos e de triatomíneos no semiárido potiguar

Trypanosoma cruzi infection was evaluated in 390 resident individuals in different rural communities of Caicó municipality, State of Rio Grande do Norte (RN). Of 28 investigated communities the soroprevalence of T. cruzi infection was 2.8% in eight rural communities individuals. The epidemiological characteristics of seropositive shown that the age ranged from 22 to 64 years, being significantly raised from 31 years (90.9%). The female gender was predominant and low education degree. Those individuals reported that they never donated blood, but they had direct contact with triatomines bug. The isolation of the parasite was performed by blood culture and xenoculture methods to determine the genetic variability of the samples. Twenty seven T. cruzi isolates were analyzed by RAPD as genetic marker using three random primers (M13-40, gt11-F and L15996). The T. cruzi isolates showed 73.7% of shared bands considering the average obtained with the three primers, and were genetically well correlated. Using this marker it was possible to separate the populations of the parasite in three distinct groups. The first group composed by isolates obtained of triatomines and humans from four different districts (Caicó, Caraúbas, Serra Negra doNorte and Governador Dix-Sept Rosado); the second contained isolates obtained of triatomines of two different species (T. brasiliensis and P. lutzi) captured in Caraúbas and Serra Negra do Norte. The third grouped isolates obtained from humans of Angicos and Caicó municipalities. In different localities of distinct mesoregions, State of RN, a profile genetic well correlated was identified among all isolates and the presence of three distinct groups of the parasite circulating among vertebrate and invertebrate hosts

Padrões cromossômicos e mapeamento de genes ribossomais 18S e 5S em peixes pelágicos Atlânticos

Cytogenetic studies in fish have been contributed significantly to a better understanding of the marine biodiversity, presenting information related to characterization, evolution and conservation of species e fisheries stocks. Among the marine species which cytogenetic data are less well known pelagic forms are detached, that despite the economic importance and conservation efforts have been suffering great pressure from the artisanal and industrial fisheries. The present work characterized cytogenetically six species of large pelagic fish in the Atlantic, belonging to the Order Perciformes, among them, four species of Scombridae, Thunnus albacares, T. obesus, Scomberomorus brasiliensis and Acanthocybium solandri and two Coryphaenidae, Coryphaena equiselis and C. hippurus using Classical cytogenetic methods as conventional staining, C-banding and Ag-NORs and molecular through staining fluorochromes AT and GC-specific and mapping of ribosomal multigene families, 18S and 5S. The identification of phylogenetic patterns and cytotaxonomic markers between the species and the presence of sex chromosomes in at least one species of Coryphaenidae, are particularly useful in the formulating of phylogenetic hypotheses, as well as comparisons between groups and populations

O efeito do regime hidrológico do semiárido na composição de espécies durante dominância de cianobactérias em um reservatório tropical

The potentially toxic cyanobacterial blooms in water bodies are spread across the globe, resulting in the loss of water quality and adverse effects on human health. In arid and semiarid regions, the hydrologic regime characterized by an annual cycle of drought and rain, change the volume and the retention time of the reservoir. Such changes affect the limnological characteristics and causing changes in composition and biomass community of cyanobacteria. The reservoir Cruzeta (Zmax = 8.7 m) is a eutrophic water supply source located in the semiarid tropical (Northeast Brazil). Raised the hypothesis that the hydrological regime of semi-arid tropical is a determining factor in the availability of resources in eutrophic water sources, which influences the composition of dominant species of cyanobacteria. The aim of this study was to analyze the changes in biomass and species composition of cyanobacteria for two annual hydrological cycles and evaluate factors drivers. The study was divided into five distinct periods (dry 2010, rain 2011, dry 2011, rain 2012, dry 2012). The dominant group found in all periods was Cyanobacteria (99% of total biomass), which contributed to the low diversity. The filamentous species Cylindrospermopsis raciborskii was present at both points in almost every study. The colonial species Microcystis panniformis and Sphaerocavum brasiliensis dominated only in periods with lower volumes of water. The diatoms contribute more to the biomass during the period of severe drought. The point near the dam (P1) had phytoplankton biomass larger than the point near the tributary (P2). The dominant species of colonial cyanobacteria lasted until the overflow in P1, and P2 this dominance was until the first rains. The redundancy analysis indicated that physical factors such as light availability and water level were the main factors driving the seasonal succession of phytoplankton. The composition of phytoplankton in spring was alternated by species of filamentous cyanobacteria in conditions of poor stability of the water column, such as Cylindrospermopsis raciborskii, and colonial species under conditions of high stability of the water column, such as Microcystis panniformis and Sphaerocavum brasiliensis. The extremes of torrential rains and severe droughts, governed by the hydrological regime of the semi-arid region led to the availability of resources in the watershed, directing the spatial and temporal dynamics of phytoplankton in the reservoir Cruzeta