496 resultados para PHYLUM CNIDARIA
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Seabather's eruption is a papulo-pruritic dermatitis caused by the nematocysts of the larvae of the jellyfish Linuche unguiculata retained in the clothing fibers. Previously reported in Brazil, this work describes fourteen cases that occurred in the State of Santa Catarina, in southern Brazil. The new cases observed over a short period of time (the first half of January, 2012), at the height of the summer season, should alert health teams to possible epidemics on the coast of the state of Santa Catarina.
Molecular diversity of fungal and bacterial communities in the marine sponge Dragmacidon reticulatum
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Microbiologia Agropecuária - FCAV
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Nephrolepis exaltata L. Schott "Bostoniensis" family Davalliaceae and Equisetum giganteum L. family Equisetaceae, Phylum Pteridophyta, exhibit a strong mechanism of dominance in the areas in which they live. Have secondary compounds with allelopathic activity. The objective of this article was evaluate allelopathic potential of two ferns species, using bioassay applying aqueous extracts of dried fronds, in cucumber and lettuce seeds, and observing germination and initial development. To observe the influence on germination was analyze the percentage of germinated seeds and germination speed index (GSI). To observe initial development was analyzed shoot and root growth of the seedlings. The bioassays revealed that no concentration significantly inhibited the germination, but germination speed was delayed gradually in two species tested, as increased the extract concentration. In initial development, all the extracts showed a tendency to inhibit the growth, and an increase in extract concentration decreasing growth of radicle and hypocotyl axis. We conclude that the aqueous extract has inhibitory activity more pronounced in early development than in seed germination, affecting the primary structures of the tested plants, corroborating with the observations of occurrences of the species in natural places where dominate and suppress the growth of other species.
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Background: Imbalance in bacterial species composition of the gut microbiota is one of the factors associated with the cause or complication of the symptoms of Crohn's disease (CD). This disequilibrium consists in the reduction of biodiversity, decrease of genus such as Bifidobacterium and elevation of species such as Escherichia coli. Human microbiota varies among subjects of a same population irrespective of their health condition and among individuals living in distinct geographic locations. In animal models, sex related differences could also be observed in gut bacterial species composition under some pathological conditions. Experiments conducted with mice have demonstrated that the manifestation of type 1 diabetes (T1D) could be under the influence of the animal sex and its serum level of testosterone, which in turn could be modulated by a particular gut microbiota. Considering the existence of similar features between T1D and CD, such as strong genetic component and malfunctioning of the immune system, we investigated whether differences could be observed in the gut microbiota dysbiosis of male and female CD patients. Methods: Fifty and 5 gut mucosal biopsies from 25 adult CD patients (11 males and 14 females) and 43 specimens of an equivalent clinical material from 22 control subjects (11 males and 11 females) were screened for bacterial biodiversity by analyzing sequences of 16SrDNA V6 region. A number of 2-3 samples each from distinct gut segments (from ileum to rectum) were taken from each subject. The 16SrDNA sequences were obtained by sequencing PCR amplicons of the corresponding gene in the Ion torrent PGM sequencer. Identification and classification of the bacterial groups followed the Ribosomal Database Project (RDP) website pipeline. The relationships of the bacterial taxa with each of the study parameters was performed by compiling the data in a MS Excel and the level of statistical significance determined by the Chi-square test. Results: A total of 3203 16SrDNA sequences were detected in the 98 biopsies samples, the majority of which matching Proteobacteria, Firmicutes, Bacterioidetes, and Actinobacteria. The percentage of DNA sequences for each of these phyla found in Male control subjects/Male CD patients was 40.5/33, 32.7/32.4, 20.8/24.5, and 4.4/4,4 for Proteobacteria, Firmicutes, Bacterioidetes, and Actinobacteria, respectively. In Female comparisons, these values were 35.6/42, 39.2/26.3, 19.8/23.3, 5.2/7. Both Male and Female CD patients presented higher numbers of sequences of Actinobacteria and Bacterioidetes than those of control subjects of the same gender. Case-control differences for Firmicutes could be observed only in female comparisons and, for Proteobacteria, although case-control differences were observed in both genders, the nature of difference was distinct, since while in CD female patients a higher number of sequences matching this phylum was detected, in males a reduced number was observed, in comparison with controls. The species responsible for the Proteobacteria variation in both gender was Escherichia coli. Conclusions: The data presented above suggest that any analysis of dysbiosis in CD must take in account the patient's gender, an observation particularly relevant for Escherichia coli, whose association with CD has been most intensively investigated and for which the present study shows a reverse quantitative variation regarding the patients' gender.
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The Antarctic is a pristine environment that contributes to the maintenance of the global climate equilibrium. The harsh conditions of this habitat are fundamental to selecting those organisms able to survive in such an extreme habitat and able to support the relatively simple ecosystems. The DNA of the microbial community associated with the rhizospheres of Deschampsia antarctica Desv (Poaceae) and Colobanthus quitensis (Kunth) BartI (Caryophyllaceae), the only two native vascular plants that are found in Antarctic ecosystems, was evaluated using a 16S rRNA multiplex 454 pyrosequencing approach. This analysis revealed similar patterns of bacterial diversity between the two plant species from different locations, arguing against the hypothesis that there would be differences between the rhizosphere communities of different plants. Furthermore, the phylum distribution presented a peculiar pattern, with a bacterial community structure different from those reported of many other soils. Firmicutes was the most abundant phylum in almost all the analyzed samples, and there were high levels of anaerobic representatives. Also, some phyla that are dominant in most temperate and tropical soils, such as Acidobacteria, were rarely found in the analyzed samples. Analyzing all the sample libraries together, the predominant genera found were Bifidobacterium (phylum Actinobacteria), Arcobacter (phylum Proteobacteria) and Faecalibacterium (phylum Firmicutes). To the best of our knowledge, this is the first major bacterial sequencing effort of this kind of soil, and it revealed more than expected diversity within these rhizospheres of both maritime Antarctica vascular plants in Admiralty Bay, King George Island, which is part of the South Shetlands archipelago. The ISME Journal (2010) 4, 989-1001; doi:10.1038/ismej.2010.35; published online 1 April 2010
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This study describes the spatio-temporal distribution, population biology, and diet of the puffer fish Lagocephalus laevigatus in Caraguatatuba Bay, south-eastern Brazil. Monthly samples were taken between August 2003 and October 2004 by trawls in two areas, south and north, at depths of 1 to 4 m. The fish were measured and their sex and reproductive stage determined. The abundance of this species was compared between areas and among months, and the items in the diet were identified and quantified. Lagocephalus laevigatus was rare in Caraguatatuba Bay, where only 199 small individuals (4.8 to 15.4 cm) were obtained in the entire study period, suggesting that this species uses the estuary as a nursery. None of the specimens of L. laevigatus captured in Caraguatatuba Bay were sexually mature. Higher densities of L. laevigatus in the bay were recorded in the south area and between October and December 2003, i.e. in the spring, suggesting that spawning may occur from late winter to spring (August through to November). The diet items consumed by L. laevigatus in Caraguatatuba Bay were, as expected from the current literature, crustaceans, mainly amphipods, and fish. However, the most-consumed item was the sea whip Leptogorgia setacea (Cnidaria). This feeding habit may be related to the presence of toxins (tetrodotoxin and saxitoxin) that are frequently found in the skin and viscera of L. laevigatus, which may be sequestered from the sea whip, which possibility still needs to be specifically evaluated.
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Dactylotrochus cervicornis (= Tridacophyllia cervicornis Moseley, 1881), which occurs in Indo-Pacific waters between 73 and 852 m, was originally described as an astraeid but was later transferred to the Caryophylliidae. Assumed to be solitary, this species has no stolons and only one elongated fossa, and is unique among azooxanthellate scleractinians in often displaying extremely long thecal extensions that are septate and digitiform. Based on both molecular phylogenetic analyses (partial mitochondrial CO1 and 16S rDNA, and partial nuclear 28S rDNA) and morphological characteristics, we propose the transfer of D. cervicornis from the Caryophylliidae to the Agariciidae, making it the first extant representative of the latter family that is solitary and from deep water (azooxanthellate). The basal position of D. cervicornis within the agariciids implied by our analyses strengthens the case for inclusion of fossil species that were solitary, such as Trochoseris, in this family and suggests that the ancestor of this scleractinian family, extant members of which are predominantly colonial and zooxanthellate, may have been solitary and azooxanthellate.
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The study of "jellyfish blooms" provides important data toward determining the causes and consequences of these phenomena; however, the definition of "bloom" remains controversial and different concepts have been adopted in recent works. By addressing the biological and convenience definitions, this study tested the adequacy of the different concepts of "blooms" for the Class Staurozoa (Cnidaria). From seasonal monitoring data of some species of Staurozoa, we concluded that stauromedusae bloom if we used the biological concept of "bloom", which considers the life cycle and resulting changes in the abundances of these animals. By contrast, the small, benthic, inconspicuous, and non-harmful stauromedusae do not bloom if we use the convenience concept of "bloom", which constrains the events to those that humans can observe and that cause damage to human activities. In other words, the same group of organisms either is or is not capable of blooming depending on which concept of "bloom" is used. In fact, previous literature has suggested that Staurozoa could not bloom, which indicates that the study of "jellyfish blooms" can be biased, considering convenience rather than biological reasoning.
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Toxosplasma gondii is the model parasite of the phylum Apicomplexa, which contains numerous obligate intracellular parasites of medical and veterinary importance, including Eimeria, Sarcocystis, Cryptosporidium, Cyclospora, and Plasmodium species. Members of this phylum actively enter host cells by a multistep process with the help of microneme protein (MIC) complexes that play important roles in motility, host cell attachment, moving junction formation, and invasion. T. gondii (Tg)MIC1-4-6 complex is the most extensively investigated microneme complex, which contributes to host cell recognition and attachment via the action of TgMIC1, a sialic acid-binding adhesin. Here, we report the structure of TgMIC4 and reveal its carbohydrate-binding specificity to a variety of galactose-containing carbohydrate ligands. The lectin is composed of six apple domains in which the fifth domain displays a potent galactose-binding activity, and which is cleaved from the complex during parasite invasion. We propose that galactose recognition by TgMIC4 may compromise host protection from galectin-mediated activation of the host immune system.
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Madrepora is one of the most ecologically important genera of reef-building scleractinians in the deep sea, occurring from tropical to high-latitude regions. Despite this, the taxonomic affinities and relationships within the genus Madrepora remain unclear. To clarify these issues, we sequenced the mitochondrial (mt) genome of the most widespread Madrepora species, M. oculata, and compared this with data for other scleractinians. The architecture of the M. oculara mt genome was very similar to that of other scleractinians, except for a novel gene rearrangement affecting only cox2 and cox3. This pattern of gene organization was common to four geographically distinct M. oculata individuals as well as the congeneric species M. minutiseptum, but was not shared by other genera that are closely related on the basis of cox1 sequence analysis nor other oculinids, suggesting that it might be unique to Madrepora. (C) 2012 Elsevier Inc. All rights reserved.
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It is believed that the exposure of organisms to harsh climate conditions may select for differential enzymatic activities, making the surviving organisms a very promising source for bioprospecting. Soil bacteria play an important role in degradation of organic matter, which is mostly due to their ability to decompose cellulose-based materials. This work focuses on the isolation and identification of cellulolytic bacteria from soil found in two environments with stressful climate conditions (Antarctica and the Brazilian semi-arid caatinga). Cellulolytic bacteria were selected using enrichments at high and low temperatures (4 or 60A degrees C) in liquid media (trypic soy broth-TSB and minimum salt medium-MM) supplemented with cellulose (1%). Many of the isolates (119 out of 254-46.9%) displayed the ability to degrade carboxymethyl-cellulose, indicating the presence of endoglucolytic activity, while only a minority of these isolates (23 out of 254-9.1%) showed exoglucolytic activity (degradation of avicel). The obtained isolates revealed a preferential endoglucolytic activity according to the temperature of enrichments. Also, the identification of some isolates by partial sequencing of the 16S rRNA gene indicated that the Bacteroidetes (e.g., Pedobacter, Chryseobacterium and Flavobacterium) were the main phylum of cellulolytic bacteria isolated from soil in Antarctica; the Firmicutes (e.g., Bacillus) were more commonly isolated from samples from the caatinga; and Actinobacteria were found in both types of soil (e.g., Microbacterium and Arthrobacter). In conclusion, this work reports the isolation of bacteria able to degrade cellulose-based material from soil at very low or very high temperatures, a finding that should be further explored in the search for cellulolytic enzymes to be used in the bioenergy industry.
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Abstract Background The metabolic capacity for nitrogen fixation is known to be present in several prokaryotic species scattered across taxonomic groups. Experimental detection of nitrogen fixation in microbes requires species-specific conditions, making it difficult to obtain a comprehensive census of this trait. The recent and rapid increase in the availability of microbial genome sequences affords novel opportunities to re-examine the occurrence and distribution of nitrogen fixation genes. The current practice for computational prediction of nitrogen fixation is to use the presence of the nifH and/or nifD genes. Results Based on a careful comparison of the repertoire of nitrogen fixation genes in known diazotroph species we propose a new criterion for computational prediction of nitrogen fixation: the presence of a minimum set of six genes coding for structural and biosynthetic components, namely NifHDK and NifENB. Using this criterion, we conducted a comprehensive search in fully sequenced genomes and identified 149 diazotrophic species, including 82 known diazotrophs and 67 species not known to fix nitrogen. The taxonomic distribution of nitrogen fixation in Archaea was limited to the Euryarchaeota phylum; within the Bacteria domain we predict that nitrogen fixation occurs in 13 different phyla. Of these, seven phyla had not hitherto been known to contain species capable of nitrogen fixation. Our analyses also identified protein sequences that are similar to nitrogenase in organisms that do not meet the minimum-gene-set criteria. The existence of nitrogenase-like proteins lacking conserved co-factor ligands in both diazotrophs and non-diazotrophs suggests their potential for performing other, as yet unidentified, metabolic functions. Conclusions Our predictions expand the known phylogenetic diversity of nitrogen fixation, and suggest that this trait may be much more common in nature than it is currently thought. The diverse phylogenetic distribution of nitrogenase-like proteins indicates potential new roles for anciently duplicated and divergent members of this group of enzymes.
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Over the last decade, molecular phylogenetics has called into question some fundamental aspects of coral systematics. Within the Scleractinia, most families composed exclusively by zooxanthellate species are polyphyletic on the basis of molecular data, and the second most speciose coral family, the Caryophylliidae (most members of which are azooxanthellate), is an unnatural grouping. As part of the process of resolving taxonomic affinities of caryophylliids', here a new Robust' scleractinian family (Deltocyathiidae fam. n.) is proposed on the basis of combined molecular (CO1 and 28S rDNA) and morphological data, accommodating the early-diverging clade of traditional caryophylliids (represented today by the genus Deltocyathus). Whereas this family captures the full morphological diversity of the genus Deltocyathus, one species, Deltocyathus magnificus, is an outlier in terms of molecular data, and groups with the Complex coral family Turbinoliidae. Ultrastructural data, however, place D.magnificus within Deltocyathiidae fam. nov. Unfortunately, limited ultrastructural data are as yet available for turbinoliids, but D.magnificus may represent the first documented case of morphological convergence at the microstructural level among scleractinian corals. Marcelo V.Kitahara, Centro de Biologia Marinha, Universidade de SAo Paulo, SAo SebastiAo, S.P. 11600-000, Brazil. E-mail:kitahara@usp.br