RESUMO
Phyllidiid nudibranchs are brightly colored gastropod molluscs, frequently encountered in coral reefs of the tropical Indo-Pacific. This study aimed to identify the phylogenetic similarities among the Phyllidia spp. The phylogenetic similarities among all the available Phyllidia spp. were studied by comparing the nucleotide sequence of 16s rRNA and cytochrome c genes (cox I). Sequences were retrieved from NCBI databases and aligned by using Geneious software. A phylogenetic tree was constructed for the retrieved sequences of Phyllidia spp. by using the neighbor-joining method on MEGA software and the pairwise distances were also calculated. The similarities among nucleotide sequences of 16s rRNA showed that the P. elegans, and P. haegeli had the highest similarities (99.92%) and the lowest similarities (99.14%) among P. haegeli and P. picta. While nucleotide sequences of cox I showed the highest similarities (99.90%) between P. elegans and P. ocellata, and the P. varicosa had the lowest similarities 99.74% with P. koehleri and P. larryi. The molecular phylogenetic analysis based on mitochondrial marker indicated a close relation between P. elegans and P. alyta in both cox I and 16s rRNA phylogenetic tree. The phylogenetic tree of 16s rRNA gene shows the P. ocellata is closely related to the clade of species P. exquisita. The available phylogenetic analysis could be useful in further studies of Phyllidiidae within Nudibranchia.
Os nudibrânquios Phyllidiid são moluscos gastrópodes de cores vivas, frequentemente encontrados em recifes de corais do Indo-Pacífico tropical. Este estudo teve como objetivo identificar as semelhanças filogenéticas entre Phyllidia spp. As semelhanças filogenéticas entre todos os Phyllidia spp. disponíveis foram estudados comparando à sequência de nucleotídeos dos genes 16s rRNA e citocromo C (cox I). As sequências foram recuperadas dos bancos de dados NCBI e alinhadas usando o software Geneious. Uma árvore filogenética foi construída para as sequências recuperadas de Phyllidia spp. através do método de junção de vizinhos no software MEGA e as distâncias pareadas também foram calculadas. As semelhanças entre as sequências de nucleotídeos do 16s rRNA mostraram que P. elegans e P. haegeli apresentaram as maiores similaridades (99,92%) e as menores similaridades (99,14%) entre P. haegeli e P. picta. Enquanto as sequências de nucleotídeos de cox I apresentaram as maiores similaridades (99,90%) entre P. elegans e P. ocellata, e a de P. varicosa apresentou as menores similaridades 99,74% com P. koehleri e P. larryi. A análise filogenética molecular baseada no marcador mitocondrial indicou uma estreita relação entre P. elegans e P. alyta tanto na árvore filogenética cox I quanto 16s rRNA. A árvore filogenética do gene 16s rRNA demonstrou que P. ocellata está intimamente relacionado ao clado da espécie P. exquisita. A análise filogenética disponível pode ser útil para estudos posteriores de Phyllidiidae dentro de Nudibranchia.
Assuntos
Animais , Filogenia , RNA Ribossômico 16S , Citocromos c , Moluscos/genética , NucleotídeosRESUMO
Physids belong to Class Gastropoda; belong to Phylum Mollusca and being bioindicators, intermediate hosts of parasites and pests hold a key position in the ecosystem. There are three species of Genus Physa i.e. P. fontinalis, Physa acuta and P. gyrina water bodies of Central Punjab and were characterized on the basis of molecular markers High level of genetic diversity was revealed by polymorphic RAPD, however SSR markers were not amplified. The multivariate analysis revealed polymorphism ranging from 9.09 percent to 50 percent among the three Physid species. Total number of 79 loci were observed for the three species under study and 24 loci were observed to be polymorphic. These RAPD fragment(s) can be developed into co dominant markers (SCAR) by cloning and can be further sequenced for the development of the Physa species specific markers to identify the introduced and native species in Pakistan.
Os físidos pertencem à classe Gastropoda; pertencem ao filo Mollusca e, sendo bioindicadores, hospedeiros intermediários de parasitas e pragas, ocupam uma posição-chave no ecossistema. Existem três espécies do gênero Physa, ou seja, P. fontinalis, Physa acuta e P. gyrina em corpos dágua do Punjab Central e foram caracterizadas com base em marcadores moleculares. Alto nível de diversidade genética foi revelado por RAPD polimórfico, no entanto os marcadores SSR não foram amplificados. A análise multivariada revelou polimorfismo variando de 9,09% a 50% entre as três espécies de Physid. Um número total de 79 loci foi observado para as três espécies em estudo e 24 loci foram observados como polimórficos. Esses fragmentos RAPD podem ser desenvolvidos em marcadores codominantes (SCAR) por clonagem e podem ser posteriormente sequenciados para o desenvolvimento de marcadores específicos da espécie Physa para identificar as espécies introduzidas e nativas no Paquistão.
Assuntos
Animais , Moluscos/genética , Variação GenéticaRESUMO
Physids belong to Class Gastropoda; belong to Phylum Mollusca and being bioindicators, intermediate hosts of parasites and pests hold a key position in the ecosystem. There are three species of Genus Physa i.e. P. fontinalis, Physa acuta and P. gyrina water bodies of Central Punjab and were characterized on the basis of molecular markers High level of genetic diversity was revealed by polymorphic RAPD, however SSR markers were not amplified. The multivariate analysis revealed polymorphism ranging from 9.09 percent to 50 percent among the three Physid species. Total number of 79 loci were observed for the three species under study and 24 loci were observed to be polymorphic. These RAPD fragment(s) can be developed into co dominant markers (SCAR) by cloning and can be further sequenced for the development of the Physa species specific markers to identify the introduced and native species in Pakistan.(AU)
Os físidos pertencem à classe Gastropoda; pertencem ao filo Mollusca e, sendo bioindicadores, hospedeiros intermediários de parasitas e pragas, ocupam uma posição-chave no ecossistema. Existem três espécies do gênero Physa, ou seja, P. fontinalis, Physa acuta e P. gyrina em corpos dágua do Punjab Central e foram caracterizadas com base em marcadores moleculares. Alto nível de diversidade genética foi revelado por RAPD polimórfico, no entanto os marcadores SSR não foram amplificados. A análise multivariada revelou polimorfismo variando de 9,09% a 50% entre as três espécies de Physid. Um número total de 79 loci foi observado para as três espécies em estudo e 24 loci foram observados como polimórficos. Esses fragmentos RAPD podem ser desenvolvidos em marcadores codominantes (SCAR) por clonagem e podem ser posteriormente sequenciados para o desenvolvimento de marcadores específicos da espécie Physa para identificar as espécies introduzidas e nativas no Paquistão.(AU)
Assuntos
Animais , Moluscos/genética , Variação GenéticaRESUMO
Galectins are an evolutionarily ancient family of lectins characterized by their affinity for ß-galactosides and a conserved binding site in the carbohydrate recognition domain (CRD). These lectins are involved in multiple physiological functions, including the recognition of glycans on the surface of viruses and bacteria. This feature supports their role in innate immune responses in marine mollusks. Here, we identified and characterized a galectin, from the mollusk Haliotis rufescens (named HrGal), with four CRDs that belong to the tandem-repeat type. HrGal was purified by affinity chromatography in a galactose-agarose resin and exhibited a molecular mass of 64.11 kDa determined by MALDI-TOF mass spectrometry. The identity of HrGal was verified by sequencing, confirming that it is a 555 amino acid protein with a mass of 63.86 kDa. This protein corresponds to a galectin reported in GenBank with accession number AHX26603. HrGal is stable in the presence of urea, reducing agents, and ions such as Cu2+ and Zn2+. The recombinant galectin (rHrGal) was purified from inclusion bodies in the presence of these ions. A theoretical model obtained with the AlphaFold server exhibits four non-identical CRDs, with a ß sandwich folding and the representative motifs for binding ß-galactosides. This allows us to classify HrGal within the tandem repeat galectin family. On the basis of a phylogenetic analysis, we found that the mollusk sequences form a monophyletic group of tetradomain galectins unrelated to vertebrate galectins. HrGal showed specificity for galactosides and glucosides but only the sulfated sugars heparin and ι-carrageenan inhibited its hemagglutinating activity with a minimum inhibitory concentration of 4 mM and 6.25 X 10-5% respectively. The position of the sulfate groups seemed crucial for binding, both by carrageenans and heparin.
Assuntos
Galectinas , Gastrópodes , Animais , Galectinas/química , Filogenia , Sulfatos , Galactosídeos/química , Gastrópodes/genética , Gastrópodes/metabolismo , Polissacarídeos , Moluscos/genética , HeparinaRESUMO
The isolation of Escherichia coli from food is a major concern. Pathogenic strains of these bacteria cause diseases which range from diarrhea to hemolytic-uremic syndrome. Therefore the virulence genes in E. coli isolates from the mussel ( Mytella guyanensis) commercialized in Cachoeira, Bahia, Brazil were investigated. Samples were purchased from four vendors: two from supermarkets and two from fair outlets. They were conditioned into isothermal boxes with reusable ice and transported to the laboratory for analysis. E. coli strains were isolated in eosin methylene blue agar, preserved in brain-heart infusion medium with 15% glycerol and stored at -20 °C, after microbiological analysis. Virulence genes in the isolated strains were identified by specific primers, with Polymerase Chain Reaction. Twenty-four isolates were obtained, with a prevalence of elt gene, typical from enterotoxigenic infection, in 75% of the isolates. The stx and bfpA genes, prevalent in enterohemorragic and enteropathogenic E. coli, respectively, were not detected. The occurrence of elt virulence-related gene in the E. coli isolates of Mytella guyanensis reveals urgent improvement in food processing, including good handling practices, adequate storage and cooking before consumption, to ensure consumers health.(AU)
O isolamento de Escherichia coli a partir de alimentos é uma grande preocupação, pois cepas patogênicas desta bactéria podem causar desde diarreia até síndrome hemolítico-urêmica. Diante do exposto, o objetivo do trabalho foi pesquisar genes de virulência em isolados de Escherichia coli provenientes do sururu Mytella guyanensis comercializado na cidade de Cachoeira, Bahia, Brasil. As amostras foram adquiridas de quatro comerciantes, sendo duas de mercados e duas em pontos de venda na feira livre da cidade de Cachoeira, acondicionadas em caixas isotérmicas com gelo reutilizável e transportadas até o laboratório para a análise. Após a análise microbiológica, as cepas de Escherichia coli foram isoladas em ágar Eosina Azul de Metileno e preservadas em caldo Brian Heart Infusion e glicerol a 15% e mantidas a - 20° C. A identificação dos genes de virulência nas cepas isoladas foi realizada utilizando primers específicos, por meio da Reação em Cadeia da Polimerase. Foram obtidos 24 isolados de Escherichia coli, destes a prevalência do gene elt , característico de Escherichia coli enterotoxigênica, foi de 75% dos isolados. Não houve a detecção dos genes stx e bfpA nos isolados, os quais são prevalentes nas cepas de Escherichia coli enterohemorrágica e Escherichia coli enteropatogênica, respectivamente. A presença do gene elt relacionado à virulência de Escherichia coli nos isolados de Mytella guyanensis revela a necessidade da melhoria no processamento, incluindo boas práticas de manipulação, armazenamento adequado e cocção previa ao consumo, visando a garantia da saúde do consumidor.(AU)
Assuntos
Animais , Moluscos/genética , Moluscos/microbiologia , Reação em Cadeia da PolimeraseRESUMO
One of the largest detriments in the abalone aquaculture industry is the inherently low growth rate of this marine gastropod. In order to confront this issue, greater molecular knowledge is needed on growth traits. Therefore, transcriptome analyses were performed using RNA-Seq for groups of California red abalones (Haliotis rufescens) cultured under the same conditions, but with high growth rates (HGR) or low growth rates (LGR). De novo assembly generated 44312 contigs used as references for RNA-Seq analysis. Results showed a total of 1437 differentially expressed contigs, among which, 435 were up-regulated in the HGR group and 1002 in LGR individuals. Overall, LGR abalones evidenced a greater number of exclusive transcripts and differentially transcribed genes. These results provide a valuable resource of novel transcripts in this species and further understandings of the molecular bases regulating growth traits in H. rufescens.
Assuntos
Moluscos/genética , Moluscos/metabolismo , Técnicas de Amplificação de Ácido Nucleico , RNA/metabolismo , Transcriptoma , Animais , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas/genética , Proteínas/metabolismo , RNA/genética , Regulação para CimaRESUMO
The red abalone Haliotis rufescens is one of the most important species for aquaculture in Baja California, México, and despite this, few gene expression studies have been done in tissues such as gill, head and gonad. For this purpose, reverse transcription and quantitative real time PCR (RT-qPCR) is a powerful tool for gene expression evaluation. For a reliable analysis, however, it is necessary to select and validate housekeeping genes that allow proper transcription quantification. Stability of nine housekeeping genes (ACTB, BGLU, TUBB, CY, GAPDH, HPRTI, RPL5, SDHA and UBC) was evaluated in different tissues of red abalone (gill, head and gonad/digestive gland). Four-fold serial dilutions of cDNA (from 25 ngµL(-1) to 0.39 ngµL(-1)) were used to prepare the standard curve, and it showed gene efficiencies between 0.95 and 0.99, with R(2)=0.99. geNorm and NormFinder analysis showed that RPL5 and CY were the most stable genes considering all tissues, whereas in gill HPRTI and BGLU were most stable. In gonad/digestive gland, RPL5 and TUBB were the most stable genes with geNorm, while SDHA and HPRTI were the best using NormFinder. Similarly, in head the best genes were RPL5 and UBC with geNorm, and GAPDH and CY with NormFinder. The technical variability analysis with RPL5 and abalone gonad/digestive gland tissue indicated a high repeatability with a variation coefficient within groups ≤ 0.56% and between groups ≤ 1.89%. These results will help us for further research in reproduction, thermoregulation and endocrinology in red abalone.
Assuntos
Perfilação da Expressão Gênica/normas , Genes Essenciais , Moluscos/genética , Reação em Cadeia da Polimerase em Tempo Real/normas , Animais , Feminino , Perfilação da Expressão Gênica/métodos , Gônadas/metabolismo , Masculino , Moluscos/metabolismo , Controle de Qualidade , Reação em Cadeia da Polimerase em Tempo Real/métodos , Padrões de Referência , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , Estudos de Validação como AssuntoRESUMO
We analysed field-collected quantitative data of benthic marine molluscs across the Cretaceous-Palaeogene boundary in Patagonia to identify patterns and processes of biodiversity reconstruction after the end-Cretaceous mass extinction. We contrast diversity dynamics from nearshore environments with those from offshore environments. In both settings, Early Palaeogene (Danian) assemblages are strongly dominated by surviving lineages, many of which changed their relative abundance from being rare before the extinction event to becoming the new dominant forms. Only a few of the species in the Danian assemblages were newly evolved. In offshore environments, however, two newly evolved Danian bivalve species attained ecological dominance by replacing two ecologically equivalent species that disappeared at the end of the Cretaceous. In both settings, the total number of Danian genera at a locality remained below the total number of late Cretaceous (Maastrichtian) genera at that locality. We suggest that biotic interactions, in particular incumbency effects, suppressed post-extinction diversity and prevented the compensation of diversity loss by originating and invading taxa. Contrary to the total number of genera at localities, diversity at the level of individual fossiliferous horizons before and after the boundary is indistinguishable in offshore environments. This indicates an evolutionary rapid rebound to pre-extinction values within less than ca 0.5 million years. In nearshore environments, by contrast, diversity of fossiliferous horizons was reduced in the Danian, and this lowered diversity lasted for the entire studied post-extinction interval. In this heterogeneous environment, low connectivity among populations may have retarded the recolonisation of nearshore habitats by survivors.
Assuntos
Biodiversidade , Evolução Biológica , Extinção Biológica , Fósseis , Moluscos/genética , Moluscos/fisiologia , Animais , Argentina , Especificidade da EspécieRESUMO
Molluscs show a wide diversity of sexual systems and strategies. There are both gastropod and bivalve families that are each primarily dioecious, simultaneous hermaphrodites, or sequential hermaphrodites, and other families in which almost every sexual strategy occurs. The multiple evolutionary transitions of sexual systems within molluscs would allow comparative analyses of the associated ecological factors, but data on all but a few groups are too sparse to draw many solid conclusions. The phylogenetic distribution of sexual systems in the Mollusca shows that gastropods and bivalves demonstrate different patterns, possibly associated with the presence/absence of copulation. The distribution of change of sex suggests that, in gastropods, sequential hermaphrodites do not evolve from simultaneous hermaphrodites, and that sex reversal (flip-flopping) occurs in free-spawners but not in copulators. Three well-studied protandrous gastropod groups (calyptraeids, coralliophilids, and patellogastropods) show similar responses to environmental conditions and associations with conspecifics. They all have the following attributes: (1) they are sedentary, (2) they live in groups, patches, or aggregates, and (3) size at sex change varies among sites and among aggregates. In addition the available experimental evidence suggests that (4) the presence of females or large individuals represses growth and sex change of males, and (5) behavior seems to mediate the repressive influence of large females. Available data from other species tend to support these patterns. Finally, the repression of growth of males by females in protandry likely facilitates the evolution of dwarf males.
Assuntos
Evolução Biológica , Modelos Biológicos , Moluscos/fisiologia , Fenótipo , Filogenia , Processos de Determinação Sexual/fisiologia , Sexo , Animais , Meio Ambiente , Feminino , Masculino , Moluscos/genética , Meio SocialRESUMO
Queen conch (Strombus gigas) are listed in CITES Appendix II. Populations may be declining due to anthropogenic inputs that include pollutants from boating activity. In the British Virgin Islands (BVI), some conch exhibit imposex, a condition in which male external genitalia are present in female conch. Previous studies suggest that tributyltin (TBT), an antifouling chemical used in boat paint, is correlated to increased incidence of imposex although the mechanisms leading to imposex are not known. The present study utilized a Queen conch microarray to measure the response of the ovarian transcriptome in conch inhabiting polluted environments with high TBT levels in the BVI. The polluted sites, Road Harbour (RH) and Trellis Bay (TB), are areas with high boating activity while the reference sites, Guana Island (GI) and Anegada (AN), are areas with low boating activity. There were 754 and 898 probes differentially expressed in the ovary of conch collected at RH and TB respectively compared to conch collected at GI. Of the genes that were differentially expressed at both sites, >10% were shared suggesting that these sites have additional environmental factors influencing gene expression patterns. Functional enrichment analysis showed that the biological processes of cell proliferation, translation, and oxidative stress were over-represented in the polluted sites. Gene set enrichment analysis revealed that transcripts involved in the biological processes of general metabolism, immune, lipid metabolism, and stress were affected in conch from polluted environments. Interestingly, altered stress genes appeared to be more prevalent in conch collected from RH than TB, corresponding to the higher TBT load at RH compared to TB. Our study shows that stress pathways are affected in conch ovary in environments that experience heavy boating activity in the BVIs, although we are unable to directly link changes at the transcriptomics level to high TBT levels.