A chemotaxis operon in the bacterium Desulfovibrio gigas is induced under several growth conditions

Abstract: The chemosensory system of bacteria controls their motility and behaviour in different environments. In the present study, we report the identification of the first chemotaxis operon in Desulfovibrio gigas. Amino acid sequence analysis revealed seven coding regions for polypeptides with a high similarity to chemotaxis proteins from other organisms. D. gigas chemotaxis operon has a similar genetic organisation to chemotaxis operons found in the sequenced genomes of Desulfovibrio desulfuricans and Desulfovibrio vulgaris. Control of gene expression was assessed by real-time reverse transcription-PCR in cells grown under different conditions. mRNA levels were enhanced in the presence of thiosulfate and sulfite and decreased upon exposure to NO. No effect was observed in the presence of O-2, NaNO2, pyruvate or fumarate. These results show that the expression of the chemotaxis operon is enhanced in the presence of thiosulfate and sulfite indicating that under these compounds a chemotactic response seems to be triggered in D. gigas

Characterization and expression analysis of the cytochrome bd oxidase operon from Desulfovibrio gigas

Abstract: Although classified as anaerobic, Desulfovibrio gigas contains a functional canonical membrane respiratory chain, including a cytochrome bd quinol oxidase as its terminal element. In the present study, we report the identification of the operon cydAB encoding the two subunits of cytochrome bd from this bacterium. Two hypothetical promoter regions and sequences resembling transcriptional regulators-binding sites have been identified. Amino acid sequence analysis revealed a high similarity to cytochrome bd from other organisms, presenting the conserved residues typical from these proteins. Reverse transcription polymerase chain reaction (RT-PCR) and Northern blot analysis confirmed the operon transcription. Gene expression was assessed by real-time RT-PCR in cells grown in different media and under exposure to oxygen and nitric oxide. mRNA levels were slightly enhanced in the presence of 150 mu M NO. However, in the presence of 10 mu M NO, a decrease was observed of the steady-state population of cydAB mRNA. No considerable effect was observed in the presence of fumarate/sulfate medium, 60 mu M O-2 or 10 mu M NO

Evolution and diversity of alpha-carbonic anhydrases in the mantle of the Mediterranean mussel (Mytilus galloprovincialis)

The α-carbonic anhydrases (α-CAs) are a large and ancient group of metazoan-specific enzymes. They generate bicarbonate from metabolic carbon dioxide and through calcium carbonate crystal formation play a key role in the regulation of mineralized structures. To better understand how α-CAs contribute to shell mineralization in the marine Mediterranean mussel (Mytilus galloprovincialis) we characterized them in the mantle. Phylogenetic analysis revealed that mollusc α-CA evolution was affected by lineage and species-specific events. Ten α-CAs were found in the Mediterranean mussel mantle and the most abundant form was named, MgNACR, as it grouped with oyster nacreins (NACR). Exposure of the Mediterranean mussel to reduced water salinity (18 vs 37 ppt), caused a significant reduction (p < 0.05) in mantle esterase activity and MgNACR transcript abundance (p < 0.05). Protonograms revealed multiple proteins in the mantle with α-CA hydratase activity and mapped to a protein with a similar size to that deduced for monomeric MgNACR. Our data indicate that MgNACR is a major α-CA enzyme in mantle and that by homology with oyster nacreins likely regulates mussel shell production. We propose that species-dependent α-CA evolution may contribute to explain the diversity of bivalve shell structures and their vulnerability to environmental changes.Agência financiadora European Union 605051 Portuguese national funds from FCT - Foundation for Science and Technology UID/Multi/04326/2019 operational programmes CRESC Algarve 2020 and COMPETE 2020 through project EMBRC FCT UID/Multi/04326/2019 SFRH/BPD/79105/2011 SFRH/BPD/89811/2012 EMBRIC (European Union's Horizon 2020 research and innovation programme) 654008 CAPES, Brazil 88887.116718/2016-00 PT ALG-01-0145-FEDER-022121info:eu-repo/semantics/publishedVersio

Allatostatin-type A, kisspeptin and galanin GPCRs and putative ligands as candidate regulatory factors of mantle function

Allatostatin-type A (AST-A), kisspeptin (KISS) and galanin (GAL) G-protein coupled receptor (GPCR) systems share a common ancestral origin in arthropods and the vertebrates where they regulate metabolism and reproduction. The molluscs are the second most diverse phylum in the animal kingdom, they occupy an important phylogenetic position, and their genome is more similar to deuterostomes than the arthropods and nematodes and thus they are good models for studies of gene family evolution and function. This mini-review intends to extend the current knowledge about AST-A, KISS and GAL GPCR system evolution and their putative function in the mollusc mantle. Comparative evolutionary analysis of the target GPCR systems was established by identifying homologues in genomes and tissue transcriptome datasets available for molluscs and comparing them to those of other metazoan systems. Studies in arthropods have revealed the existence of the AST-A system but the loss of homologues of the KISS and GAL systems. Homologues of the insect AST-AR and vertebrate KISSR genes were found in molluscs but putative GALR genes were absent. Receptor gene number suggested that members of this family have suffered lineage specific evolution during the molluscan radiation. In molluscs, orthologues of the insect AST-A peptides were not identified but buccalin peptides that are structurally related were identified and are putative receptor agonists. The identification of AST-AR and KISSR genes in molluscs strengthens the hypotheses that in metazoans members of the AST-AR subfamily share evolutionary proximity with KISSRs. The variable number of receptors and large repertoire of buccalin peptides may be indicative of the functional diversity of the AST-AR/IGSSR systems in molluscs. The identification of AST-A and KISS receptors and ligands in the mantle transcriptome indicates that in molluscs they may have acquired a novel function and may play a role in shell development or sensory detection in the mantle

PACAP system evolution and its role in melanophore function in teleost fish skin

Pituitary adenylate cyclase-activating polypeptide (PACAP) administered to tilapia melanophores ex-vivo causes significant pigment aggregation and this is a newly identified function for this peptide in fish. The G-protein coupled receptors (GPCRs), adcyap1r1a (encoding Pac1a) and vipr2a (encoding Vpac2a), are the only receptors in melanophores with appreciable levels of expression and are significantly (p < 0.05) down-regulated in the absence of light. Vpac2a is activated exclusively by peptide histidine isoleucine (PHI), which suggests that Pac1a mediates the melanin aggregating effect of PACAP on melanophores. Paradoxically activation of Pac1a with PACAP caused a rise in cAMP, which in fish melanophores is associated with melanin dispersion. We hypothesise that the duplicate adcyap1ra and vipr2a genes in teleosts have acquired a specific role in skin and that the melanin aggregating effect of PACAP results from the interaction of Pac1a with Ramp that attenuates cAMP-dependent PKA activity and favours the Ca(2+)/Calmodulin dependent pathway.info:eu-repo/semantics/publishedVersio

Integração de cuidados: Experiência e perceção do cidadão em Portugal

O Serviço Social define-se como uma profissão orientada para valores sociais e radica tanto nas contribuições técnicas como na sua dimensão ética e moral, a sua projeção/intervenção em face a objetivos transformadores, individuais e comunitários está além da sua ação concreta (Rossel, 1996). A centralidade no utente só pode ser conseguida se este for ouvido, se as suas experiências perceções e visões forem auscultadas, trabalhadas e devidamente transformadas no que será um serviço mais próximo, útil, otimizando e dinamizando os cuidados que são prestados, podendo contribuir para a própria otimização do trabalho dos profissionais, tornando-o inclusive mais facilitador. Define-se como objetivo de estudo identificar e analisar o conhecimento e as experiências que os utentes têm sobre o serviço nacional de saúde e a integração de cuidados. Com a presente investigação pretende-se validar e avaliar as experiências dos utentes, propondo um conjunto de dimensões relevantes para a melhoria dos cuidados no serviço nacional de saúde, serviços sociais e integração de cuidados, através da perspetiva do utente. Os resultados sugerem que a integração de cuidados é vista com um projeto em construção, necessário e fundamental para uma melhor prestação de cuidados ao utente. A integração de cuidados é vista pelos utentes como uma articulação, entre diversos prestadores, que tenha no centro da sua ação o utente e as famílias, promovendo fatores facilitadores de aproximação ao seu acompanhamento clínico e social, prevenindo situações de agudização.Social Service is defined as a profession orientated towards social values and is rooted both in its technical contributions and in its ethical and moral dimension, its projection/intervention in the face of transformative, individual and community objectives is beyond its concrete action (Rossel, 1996). The centrality of the user can only be achieved if he/she is heard, if his/her experiences, perceptions and visions are listened to, worked on and duly transformed into what will be a closer, more useful service, optimising and boosting the care provided, which may contribute to the very optimisation of the professionals' work, even making it easier. The study objective was to identify and analyse the knowledge and experiences that users have of the national health service and the integration of care. This research aims to validate and assess users' experiences, proposing a set of relevant dimensions for improving care in the national health service, social services and care integration, through the users' perspective. The results suggest that care integration is seen as a project under construction, necessary and essential for a better provision of care to the patient. The users see care integration as an articulation between different providers that focuses their actions on the patient and the families, promoting facilitating factors that bring them closer to their clinical and social follow-up, preventing situations of aggravation

Plasmodium infection alters Anopheles gambiae detoxification gene expression

ABSTRACT: BACKGROUND: Anopheles gambiae has been shown to change its global gene expression patterns upon Plasmodium infection. While many alterations are directly related to the mosquito's innate immune response, parasite invasion is also expected to generate toxic by-products such as free radicals. The current study aimed at identifying which loci coding for detoxification enzymes are differentially expressed as a function of Plasmodium berghei infection in midgut and fat body tissues. RESULTS: Using a custom-made DNA microarray, transcript levels of 254 loci primarily belonging to three major detoxification enzyme families (glutathione S-transferases, cytochrome P450 monooxygenases and esterases) were compared in infected and uninfected mosquitoes both during ookinete invasion and the release of sporozoites into the hemocoel. The greatest changes in gene expression were observed in the midgut in response to ookinete invasion. Interestingly, many detoxification genes including a large number of P450s were down-regulated at this stage. In the fat body, while less dramatic, gene expression alterations were also observed and occurred during the ookinete invasion and during the release of sporozoites into the hemocoel. While most gene expression changes were tissue-related, CYP6M2, a CYP previously associated with insecticide resistance, was over-expressed both in the midgut and fat body during ookinete invasion. CONCLUSIONS: Most toxicity-related reactions occur in the midgut shortly after the ingestion of an infected blood meal. Strong up-regulation of CYP6M2 in the midgut and the fat body as well as its previous association with insecticide resistance shows its broad role in metabolic detoxificatio

Evolution of the glucagon-like system across fish

In fishes, including the jawless lampreys, the most ancient lineage of extant vertebrates, plasma glucose levels are highly variable and regulation is more relaxed than in mammals. The regulation of glucose and lipid in fishes in common with mammals involves members of the glucagon (GCG)-like family of gastrointestinal peptides. In mammals, four peptides GCG, glucagon-like peptide 1 and 2 (GLP1 and GLP2) and glucose-dependent insulinotropic peptide (GIP) that activate four specific receptors exist. However, in lamprey and other fishes the glucagon-like family evolved differently and they retained additional gene family members (glucagon-related peptide, gcrp and its receptor, gcrpr) that are absent from mammals. In the present study, we analysed the evolution of the glucagon-like system in fish and characterized gene expression of the family members in the European sea bass (Dicentrarchus labrax) a teleost fish. Phylogenetic analysis revealed that multiple receptors and peptides of the glucagon-like family emerged early during the vertebrate radiation and evolved via lineage specific events. Synteny analysis suggested that family member gene loss is likely to be the result of a single gene deletion event. Lamprey was the only fish where a putative glp1r persisted and the presence of the receptor gene in the genomes of the elephant shark and coelacanth remains unresolved. In the coelacanth and elephant shark, unique proglucagon genes were acquired which in the former only encoded Gcg and Glp2 and in the latter, shared a similar structure to the teleost proglucagon gene but possessed an extra exon coding for Glp-like peptide that was most similar to Glp2. The variable tissue distribution of the gene transcripts encoding the ligands and receptors of the glucagon-like system in an advanced teleost, the European sea bass, suggested that, as occurs in mammals, they have acquired distinct functions. Statistically significant (p < .05) down-regulation of teleost proglucagon a in sea bass with modified plasma glucose levels confirmed the link between these peptides and metabolism. The tissue distribution of members of the glucagon-like system in sea bass and human suggests that evolution of the brain-gut-peptide regulatory loop diverged between teleosts and mammals despite the overall conservation and similarity of glucagon-like family members.FCT: SFRH/BD/103185/2014info:eu-repo/semantics/publishedVersio

The calcitonin-like system is an ancient regulatory system of biomineralization

Biomineralization is the process by which living organisms acquired the capacity to accumulate minerals in tissues. Shells are the biomineralized exoskeleton of marine molluscs produced by the mantle but factors that regulate mantle shell building are still enigmatic. This study sought to identify candidate regulatory factors of molluscan shell mineralization and targeted family B G-protein coupled receptors (GPCRs) and ligands that include calcium regulatory factors in vertebrates, such as calcitonin (CALC). In molluscs, CALC receptor (CALCR) number was variable and arose through lineage and species-specific duplications. The Mediterranean mussel (Mytilus galloprovincialis) mantle transcriptome expresses six CALCR-like and two CALC-precursors encoding four putative mature peptides. Mussel CALCR-like are activated in vitro by vertebrate CALC but only receptor CALCRIIc is activated by the mussel CALCIIa peptide (EC50 = 2.6 ×10-5 M). Ex-vivo incubations of mantle edge tissue and mantle cells with CALCIIa revealed they accumulated significantly more calcium than untreated tissue and cells. Mussel CALCIIa also significantly decreased mantle acid phosphatase activity, which is associated with shell remodelling. Our data indicate the CALC-like system as candidate regulatory factors of shell mineralization. The identification of the CALC system from molluscs to vertebrates suggests it is an ancient and conserved calcium regulatory system of mineralization.CCMAR UIDB/04326/2020; CRESC Algarve 2020 and COMPETE 2020 through project EMBRC.PT ALG-01-0145-FEDER-022121. FCT: DL57/2016/CP1361/CT0020info:eu-repo/semantics/publishedVersio