Localization and distribution of nitric oxide synthase and other neuronal markers in the podia ofHolothuria arguinensis

The organization of the nervous system of the holothurian podia-the tentacles, papillae, and tube feet-is still poorly understood, which limits the development of functional studies. Knowledge of nitric oxide (NO) signaling in sea cucumbers is nonexistent, although it is known to play an important role in many essential biological functions, including neurotransmission, throughout the animal kingdom. The objective of this study was to characterize the holothurian podia inHolothuria arguinensis. To this end, we used classical histology, nitric oxide synthase (NOS) distribution, using NADPH-diaphorase histochemistry and NOS immunostaining, and neuronal immunohistochemistry. Our results revealed an abundant distribution of NO in the nervous components of the holothurian podia, suggesting an important role for NO as a neuronal messenger in these structures. Nitrergic fibers were intensely labeled in the longitudinal nerve and the nerve plexus surrounding the stem, but were more weakly labeled in the mesothelium. NOS was also found in scattered cell bodies and abundant fibers in the podia terminal end (i.e., the discs in tentacles and tube feet, and the pointed conical structures in the papillae), with evident neuronal projections to the bud surface, especially in the tentacles. The podia terminal end was the most specialized area and was characterized by a specific nervous arrangement, consisting of a distinct nerve plate, rich in cells and fibers containing potential sensory cells staining positively for neuronal markers, which makes this the most likely candidate to be a chemosensory region and an important candidate for future exploration.Fundacao para a Ciencia e a TecnologiaPortuguese Foundation for Science and TechnologyEuropean Commission [SFRH/BD/90761/2012, UIDB/04326/2020]info:eu-repo/semantics/publishedVersio

Biogeographical patterns of endolithic infestation in an invasive and an indigenous intertidal marine ecosystem engineer

By altering the phenotypic properties of their hosts, endolithic parasites can modulate the engineering processes of marine ecosystem engineers. Here, we assessed the biogeographical patterns of species assemblages, prevalence and impact of endolithic parasitism in two mussel species that act as important ecosystem engineers in the southern African intertidal habitat, Perna perna and Mytilus galloprovincialis. We conducted large-scale surveys across three biogeographic regions along the South African coast: the subtropical east coast, dominated by the indigenous mussel, P. perna, the warm temperate south coast, where this species coexists with the invasive Mediterranean mussel, M. galloprovincialis, and the cool temperate west coast dominated by M. galloprovincialis. Infestation increased with mussel size, and in the case of M. galloprovincialis we found a significantly higher infestation in the cool temperate bioregion than the warm temperate region. For P. perna, the prevalence of infestation was higher on the warm temperate than the subtropical region, though the difference was marginally non-significant. On the south coast, there was no significant difference in infestation prevalence between species. Endolith-induced mortality rates through shell collapse mirrored the patterns for prevalence. For P. perna, endolith species assemblages revealed clear grouping by bioregions. Our findings indicate that biogeography affects cyanobacteria species composition, but differences between biogeographic regions in their effects are driven by environmental conditions.Agência financiadora Número do subsídio Fundacao para a Ciencia e Tecnologia (FCT-MEC, Portugal) UID/Multi/04326/2019 IF/01413/2014/CP1217/CT0004 South African Research Chairs Initiative (SARChI) of the Department of Science and Technology National Research Foundationinfo:eu-repo/semantics/publishedVersio

Study of the reproductive biology and chemical communication of sea cucumbers (Holothuria arguinensis and H. mammata)

New sea cucumber fisheries are emerging in the Mediterranean Sea and Atlantic Ocean in response to a strong Chinese market demand. However, little is known about the biology of the new target species, hindering decisions on their management. The main objective of the present thesis was to study the reproductive biology and the role played by chemical communication and chemosensory systems in Holothuria arguinensis and Holothuria mammata. The different populations sampled in a narrow range along the Iberian Peninsula varied in size/weight, gonadal production, and maturity profile within each species, suggesting the influence of singular features of each location. However, they had all the same general reproductive pattern with a summer-autumn spawning. These results, essential to manage populations, were also useful to determine when to develop bioassays to test whether and how these species communicate during reproduction. Male sea cucumbers, but not females, release chemicals that attract and induce spawning in both sexes. A preliminary analysis of the male spawning water suggests a pheromone with multiple components, among them possibly phosphatidylcholine derivatives. Histology, histochemistry and immunohistochemistry of the potential chemosensory structures involved in the detection of these cues – tentacles, papillae and tube feet – show no obvious differences between them. However, the disc was the most specialized area, with a specific nerve arrangement, rich in nitric oxide synthase and containing numerous cells some of which are likely sensory neurons. The analysis of tissue transcriptomes revealed the presence of at least 591 G-protein-coupled receptors among them at least seven putative odorant receptors distributed mainly in the tentacles, oral cavity, calcareous ring and, papillae and tegument. Overall, this thesis gives valuable insights for sea cucumber fisheries management in the region and a better understanding of how sea cucumbers communicate during reproduction.Estão a emergir novas pescarias de pepinos do mar no mar Mediterrâneo e Oceano Atlântico em resposta à forte procura do mercado chinês. Contudo, sabe-se pouco sobre a biologia e história de vida destas novas espécies alvo, o que prejudica as decisões sobre a sua gestão. O principal objectivo desta tese é o estudo da biologia reprodutiva e o papel da comunicação química e sistema quimiosensorial em Holothuria arguinensis e Holothuria mammata. Sabe-se que a comunicação química está envolvida nos processos reproductivos em vários invertebrados marinhos. No entanto, tem sido pouco investigada nos equinodermes e sabe-se pouco acerca da natureza química dos compostos e dos mecanismos sensoriais envolvidos, assim como dos efeitos que desencadeia. Esta tese tem como objectivos específicos: i) adquirir conhecimentos sobre as características reprodutivas das espécies de interesse, ii) determiner se e como os pepinos do mar comunicam durante a reprodução e procurar identificar os compostos envolvidos, iii) caracterizar as estruturas em contacto directo com o ambiente que potencialmente estão envolvidas na detecção de sinais químicos, e iv) caracterizar o reportório de quimioreceptores e identificar possíveis receptores de odorantes nos tecidos analisados. As populações de H. arguinensis e H. mammata amostradas numa estreita faixa territorial da Peninsula Ibérica variaram tamanho, perfil de produção e maturação das gónadas, o que sugere a influência de características únicas de cada local. Havia maiores indivíduos de H. arguinensis e com gónadas mais pesadas em Sagres e na Ria Formosa comparado com Olhos de Água onde se encontraram mais indivíduos imaturos. A gametogénese e a postura era mais longa em Sagres o que pode ser devido a condições nutricionais e de maré (subtidal vs intertidal). Os indivíduos de H. mammata na Ria Formosa também eram maiores e com gónadas mais pesadas do que em Murcia e Olhos de Água, possivelmente ligado a diferenças n alimentação devido ao tipo de substrato (vasa/areia vs rochas). Estes resultados, incluindo o tamanho à primeira maturação e fecundidade, são importantes para a gestão das espécies nestas regiões. Além disso, sabendo quendo estas espécies se reproduzem permitiu determiner quando deviam ser feitos os bioensaios para estudar a comunicação química nos pepinos de mar. Os bioensaios tiveram como objectivo testar a hipótese de que os pepinos de mar libertam químicos durante a agregação e postura. Os resultados mostram que a água condicionada por machos, mas não homogenatos de gónada ou fluido celómico, atrai machos e fêmeas. Também, a água condicionada de macho, com ou sem espermatozóides, induziu a postura em ambos o sexos, sendo que a água de fêmea não teve qualquer efeito. Isto mostrou claramente que os machos atraem e induzem a postura em ambos os sexos. A água de macho foi analisada através de cromatografia líquida associada a espectrometria de massa, sendo identificada a presença de derivados de fosfatidil colina; contudo, a sua função potencial como feromonas necessita de confirmação experimental. As estruturas corporais em contacto difecto com o ambiente – os tentáculos, as papilas e os pés ambulacrários – e potencialmente envolvidos ma detecção de estímulos químicos foram caracterizadas através de histologia, histoquímica e imunocitoquímica para identificar terminais nervosos que pudessem ser utilizados para electrofisiologia e fazer a triagem dos possíveis coompostos feromonais. Não se encontraram diferenças óbvias na organização nervosa e tecidular. Contudo, o disco na extremidade destas estruturas parece ser um candidato promissor para ensaios electrofisiológicos futuros pois confirma-se ser a área snsorial de cada estrutura.Ó disco caracteriza-s por um arranjo nervoso específico, incluindo uma placa nervosa distinta, rica em óxido nitroso e contendo abundantes células, muitas das quais positivas para sinaptotagmina e serotonina, provavelmente neurónios sensoriais anteriormemte descritos. Finalmente, para melhor compreender como a percepção sensorial ocorre nos pepinos do mar, o reportório de receptores acoplados a proteínas G (GPCR) foram analisados em seis bibliotecas de transcriptómica de diferentes tecidos (tentáculos, ovário, testículo, cavidade oral, anel calcáreo, papila e tegumento). Foram identificados 591 GPCR através de pesquisa de sequências por semelhança; contudo não foram encontrados ortólogos de receptores de odorantes humanos. Através da análise filogenética, que incluiu sequências proteicas de humano, enguia anfioxo, ouriço marinho e anémona, pelo menos sete receptores de odorantes foram encontrados no pepino do mar. Estas sequências pertencem a dois grupos, um mais próximo do ouriço do mar e outro mais próximo da anémona, o que sugere origem de diferentes ancestrais. Foram encontrados amino ácidos conservados característicos da assinatura de receptores de odorantes de metazoários. Além disso, estes estavam presentes principalmente nos tentáculos, cavidade oral, anel calcário, papila e tegumento, em acordo com uma potencial função sensorial. No seu conjunto, esta tese fornece nova e importante informação para a gestão dos pepinos do mar e para melhor compreender como comunicam durante a reprodução

Sea cucumbers, Holothuria arguinensis and H-mammata, from the southern Iberian Peninsula: variation in reproductive activity between populations from different habitats

New fisheries in the western Mediterranean and north eastern Atlantic target the sea cucumbers Holothuria arguinensis and H. mammata; however, lack of biological information hinders management decisions. Here, the reproductive biology of populations the two species was investigated in the southern Iberian Peninsula. Different populations located along a narrow latitudinal range displayed the same general reproductive pattern of summer-autumn spawning. However, significant differences in size, gonadal production and maturity profile between locations suggests the influence of site-specific factors. In Sagres and Ria Formosa H. arguinensis individuals were larger and had larger gonads than in Olhos de Agua, which had relatively more immature animals. The spawning and active gametogenesis periods were also longer in Sagres, possibly linked to specificity of food availability and tidal conditions. Ria Formosa also had larger H. mammata individuals with larger gonads than in Murcia and Olhos de Agua, possibly reflecting differences in feeding activity in different substrates (muddy/sandy vs rocky). Gametogenesis in H. arguinensis may be triggered by decreasing photoperiod and temperature, and spawning by increasing temperature. Altogether, these results, which include fecundity and size at first maturity, provide an important basis for the scientific management of sea cucumber fisheries in the region. (C) 2017 Elsevier B.V. All rights reserved

A new subfamily of ionotropic glutamate receptors unique to the echinoderms with putative sensory role

Chemosensation is a critical signalling process in animals and especially important in sea cucumbers, a group of ecologically and economically important marine echinoderms (class Holothuroidea), which lack audio and visual organs and rely on chemical sensing for survival, feeding and reproduction. The ionotropic receptors are a recently identified family of chemosensory receptors in insects and other protostomes, related to the ionotropic glutamate receptor family (iGluR), a large family of membrane receptors in metazoan. Here we characterize the echinoderm iGluR subunits and consider their possible role in chemical communication in sea cucumbers. Sequence similarity searches revealed that sea cucumbers have in general a higher number of iGluR subunits when compared to other echinoderms. Phylogenetic analysis and sequence comparisons revealed GluH as a specific iGluR subfamily present in all echinoderms. Homologues of the vertebrate GluA (aka alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, AMPA), GluK (aka kainate) and GluD (aka delta) were also identified. The GluN (aka N-methyl-d-aspartate, NMDA) as well as the invertebrate deuterostome subfamily GluF (aka phi) are absent in echinoderms. The echinoderm GluH subfamily shares conserved structural protein organization with vertebrate iGluRs and the ligand binding domain (LBD) is the most conserved region; genome analysis indicates evolution via lineage and species-specific tandem gene duplications. GluH genes (named Grih) are the most highly expressed iGluRs subunit genes in tissues in the sea cucumber Holothuria arguinesis, with Griha1, Griha2 and Griha5 exclusively expressed in tentacles, making them candidates to have a chemosensory role in this species. The multiple GluH subunits may provide alternative receptor assembly combinations, thus expanding the functional possibilities and widening the range of compounds detected during aggregation and spawning in echinoderms.info:eu-repo/semantics/publishedVersio

Current Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Elderly French People: Troublesome Clones on the Horizon.

In 2015, we conducted at 44 healthcare facilities (HCFs) and 21 nursing homes (NHs) a 3-month bloodstream infection (BSI) survey, and a 1-day prevalence study to determine the rate of carriage of methicillin-resistant Staphylococcus aureus (MRSA) in 891 patients and 470 residents. We investigated the molecular characteristics of the BSI-associated and colonizing MRSA isolates, and assessed cross-transmission using double-locus sequence typing and pulsed-field gel electrophoresis protocol. The incidence of MRSA-BSI was 0.040/1000 patient-days (19 cases). The prevalence of MRSA carriage was 4.2% in patients (n = 39) and 8.7% in residents (n = 41) (p < 0.001). BSI-associated and colonizing isolates were similar: none were PVL-positive; 86.9% belonged to clonal complexes 5 and 8; 93.9% were resistant to fluoroquinolones. The qacA/B gene was carried by 15.8% of the BSI-associated isolates [3/3 BSI cases in intensive care units (ICUs)], and 7.7% of the colonizing isolates in HCFs. Probable resident-to-resident transmission was identified in four NHs. Despite generally reassuring results, we identified two key concerns. First, a worryingly high prevalence of the qacA/B gene in MRSA isolates. Antisepsis measures being crucial to prevent healthcare-associated infections, our findings raise questions about the potential risk associated with chlorhexidine use in qacA/B(+) MRSA carriers, particularly in ICUs. Second, NHs are a weak link in MRSA control. MRSA spread was not controlled at several NHs; because of their frequent contact with the community, conditions are favorable for these NHs to serve as reservoirs of USA300 clone for local HCFs

Caracterização e avaliação dos percursos pedestres da ilha de Santa Maria

XIV Expedição Científica do Departamento de Biologia - Santa Maria 2009.Na Expedição Científica à ilha de Santa Maria realizada entre 12 e 19 de Julho de 2009, foram caracterizados e avaliados os 3 trilhos pedestres classificados da ilha: Entre a Serra e o Mar - PRC3 SMA, Santo Espírito e a Maia - PR4 SMA e Pico Alto e Anjos - PR2 SMA. Do levantamento efectuado ressaltaram aspectos importantes, tais como: os trilhos encontram-se no geral bem preservados, ainda que existam situações pontuais de falta de informação e/ou segurança para os visitantes; o património natural e cultural da ilha de Santa Maria é vasto, e tem um elevado potencial para a prática de actividades turísticas relacionadas com a natureza. A baixa densidade populacional da ilha (57,5 habitantes/km ), e a vigilância atenta de associações ecológicas, como os “Amigos dos Açores”, terão decerto um papel importante na preservação e manutenção dos trilhos pedestres. Ainda assim, verificou-se no trilho PR4 SMA alguma deposição de resíduos, sobretudo no troço que desce até à antiga fábrica da baleia, provavelmente da responsabilidade dos locais que aí se deslocam para a prática de pesca desportiva; no trilho PR2 SMA, o Barreiro da Faneca é palco de actividades lúdicas TT potencialmente nefastas para o ambiente local, e é difícil, a partir do último troço do percurso, encontrar a melhor direcção para o lugar dos Anjos

Holothurians have a reduced GPCR and odorant receptor-like repertoire compared to other echinoderms

Sea cucumbers lack vision and rely on chemical sensing to reproduce and survive. However, how they recognize and respond to environmental cues remains unknown. Possible candidates are the odorant receptors (ORs), a diverse family of G protein-coupled receptors (GPCRs) involved in olfaction. The present study aimed at characterizing the chemosensory GPCRs in sea cucumbers. At least 246 distinct GPCRs, of which ca. 20% putative ORs, were found in a transcriptome assembly of putative chemosensory (tentacles, oral cavity, calcareous ring, and papillae/tegument) and reproductive (ovary and testis) tissues from Holothuria arguinensis (57 ORs) and in the Apostichopus japonicus genome (79 ORs). The sea cucumber ORs clustered with those of sea urchin and starfish into four main clades of gene expansions sharing a common ancestor and evolving under purifying selection. However, the sea cucumber ORs repertoire was the smallest among the echinoderms and the olfactory receptor signature motif LxxPxYxxxxxLxxxDxxxxxxxxP was better conserved in cluster OR-l1 which also had more members. ORs were expressed in tentacles, oral cavity, calcareous ring, and papillae/tegument, supporting their potential role in chemosensing. This study is the first comprehensive survey of chemosensory GPCRs in sea cucumbers, and provides the molecular basis to understand how they communicate.Portuguese Foundation for Science and Technology: UIDB/04326/2020info:eu-repo/semantics/publishedVersio

phiD12-Like Livestock-Associated Prophages Are Associated With Novel Subpopulations of Streptococcus agalactiae Infecting Neonates

Group B Streptococcus (GBS) is a major cause of invasive disease in neonates worldwide. Monitoring data have revealed a continuing trend toward an increase in neonatal GBS infections, despite the introduction of preventive measures. We investigated this trend, by performing the first ever characterization of the prophage content for 106 GBS strains causing neonatal infections between 2002 and 2018. We determined whether the genome of each strain harbored prophages, and identified the insertion site of each of the prophages identified. We found that 71.7% of the strains carried at least one prophage, and that prophages genetically similar to livestock-associated phiD12, carrying genes potentially involved in GBS pathogenesis (e.g., genes encoding putative virulence factors and factors involved in biofilm formation, bacterial persistence, or adaptation to challenging environments) predominated. The phiD12-like prophages were (1) associated with CC17 and 1 strains (p = 0.002), (2) more frequent among strains recovered during the 2011–2018 period than among those from 2002–2010 (p < 0.001), and (3) located at two major insertion sites close to bacterial genes involved in host adaptation and colonization. Our data provide evidence for a recent increase in lysogeny in GBS, characterized by the acquisition, within the genome, of genetic features typical of animal-associated mobile genetic elements by GBS strains causing neonatal infection. We suggest that lysogeny and phiD12-like prophage genetic elements may have conferred an advantage on GBS strains for adaptation to or colonization of the maternal vaginal tract, or for pathogenicity, and that these factors are currently playing a key role in the increasing ability of GBS strains to infect neonates