Refining the ecological role of stingrays in coral reef ecosystems

Coral reefs are some of the most diverse and complex ecosystems in the world. They are known for their ability to support a high diversity of marine life. Unfortunately, coral reefs and their associated marine life are under intense anthropogenic pressures; climate change, habitat loss and overfishing are some of the main threats. These pressures also have negative effects on stingrays inhabiting coral reef areas. Management and conservation of stingrays is currently hindered by a lack of knowledge on essential aspects of their ecology. Therefore, this thesis aimed to refine the roles juvenile stingrays play in coral reef habitats and determine the importance of coral reef habitat to stingray populations in a nursery area in the Great Barrier Reef. To do so, this thesis addressed five specific aims: (1) review the current knowledge on batoid nursery areas; (2) identify movement patterns and determine habitat use of juvenile cowtail stingrays Pastinachus ater; (3) evaluate the accuracy of towed-float GPS tags to assess movement patterns and habitat use of stingrays; (4) identify diel movement patterns and habitat use of juvenile mangrove whiprays Urogymnus granulatus; and (5) investigate the relative trophic relationships of four juvenile elasmobranch species within a communal nursery area, with an emphasis on stingrays. Nursery areas are crucial for many elasmobranch species, providing advantages such as increased access to prey and reduced mortality. To date, batoid nurseries have been poorly studied in comparison with shark nurseries. The current decline of batoid populations worldwide, resulting in serious extinction threats, highlights the importance of better understanding these critical habitats. This dissertation presented a synthesis of the available knowledge on batoid nurseries and suggests the use of a combination of well-established criteria to standardize batoid nursery definition. Two telemetry approaches were used to examine movement patterns and habitat use of two stingray species commonly found in coral reef habitats: cowtail stingrays Pastinachus ater and mangrove whiprays Urogymnus granulatus. First, active acoustic telemetry was used to investigate cowtail stingray movements. Active acoustic telemetry provided fine-scale results, but had some limitations (e.g. potential human disturbance and difficulties in performing night tracks). Therefore, a new method was developed – towed-float GPS telemetry –- to investigate mangrove whipray activity patterns and habitat use. Lastly, stable isotope analysis was used to define the contribution of potential carbon sources in the food web and the trophic position and relationship of four juvenile elasmobranch species (mangrove whipray, cowtail stingray, blacktip reef shark Carcharhinus melanopterus and giant shovelnose ray Glaucostegus typus). Active acoustic telemetry results generated a total of 14 active tracks of cowtail stingrays ranging from 4.91 to 9 hours. Cowtail stingrays moved at an average speed of 2.44 m.min⁻¹ + 0.87 SE, with minimum distances travelled ranging from 546 to 1446 meters. Tracking data showed that juvenile cowtail stingrays move in response to tidal cycles, moving faster and with straighter pathways during incoming and outgoing tides, compared to low and high tides. Juvenile cowtail stingrays also showed a strong affinity to sand flat areas and mangrove edge areas, but were infrequently detected in mangrove root habitats. These areas provide food resources and potential refuges for juvenile rays to avoid potential predators. Reef crest habitats were identified as secondary refuge for juveniles during the lowest tides. Towed-float GPS tags were tested on juvenile stingrays with active tracking performed simultaneously for comparison. Individuals travelled 1332.15 ± 269.58 m SE across Pioneer Bay at an average speed of 6.87 m.min⁻¹ and average tracking time of 3.7 hours. Stationary tests demonstrated that the quality of the data obtained by towed-float GPS tags could not be matched by active, acoustic or ARGOS telemetry – on average reaching 99% of successful location recording and <15 meters accuracy. Location Error varied significantly based on the number of satellites detected, with error decreasing as satellite number increased. Towed-float GPS telemetry showed juvenile mangrove whiprays travelled distances from 394 to 2189 meters during tracks, moving at a mean rate of movement of 4.51 m.min⁻¹ ± 3.1 SE with track durations ranging from 1.5 to 9.0 hours. Juvenile mangrove whipray movements were strongly influenced by tidal cycles and rate of movement was significantly different between day and night. Individuals moved faster and chose more direct paths during the outgoing and incoming tide, and were significantly faster during the day than at night. Juvenile mangrove whiprays showed preference for mangrove root habitats during high tides. These areas are thought to reduce juvenile stingray predation risk. Stable isotope analysis showed all juvenile elasmobranchs in Pioneer Bay are at a trophic level of ~4. Isotopic niche size of blacktip reef sharks was smaller than both stingrays, and cowtail stingrays showed the largest niche size. Results showed strong evidence of niche partitioning between mangrove whiprays and cowtail stingrays with differences in feeding strategy. Nearshore pelagic and benthic prey items (e.g. crabs, annelid worms and small baitfishes) contributed most to juvenile elasmobranch diets, while mangrove or offshore prey and carbon sources appear to not have significant input. Results of telemetry and stable isotope analysis revealed juvenile stingrays were fully dependent on the Pioneer Bay system. This dissertation confirms juvenile stingrays play important roles as mesopredators and energetic links within the Pioneer Bay nursery area. By looking at fine scale movements and trophic relationships, this PhD provides important information to better understanding juvenile stingray's ecology, but also to support management and conservation policies

Sawfish (Pristidae) records along the Eastern Amazon coast

Sawfishes are the most endangered cartilaginous fishes on the planet. Their external morphology facilitates entanglement in fishing nets and their K-selected life history hinders the recovery of exploited populations. The Eastern Amazon coast (EAC) is known to be an area where sawfishes occur in Brazil, but few studies have been conducted in the area to better understand their biology and ecology. The present study reports sawfish captures along the coast of Brazil's second largest state. Data were collected from interviews with fishermen, a literature review, and media reports. In total, 23 captures were recorded between 1984 and 2016. Records include adults, a pregnant female with near-term embryos, juveniles, and young-of-the-year specimens. Most catches were reported in the Canal do Navio, an area under strong human pressure. Sawfish saws are valuable items and, for many anglers in precarious economic and social situations, high market prices eclipse the fishing prohibitions laid down under federal laws. Urgent research is required to understand sawfishes' life history, identify their critical habitats, and effectively manage and conserve these species along the EAC

Alternative Polyadenylation and Nonsense-Mediated Decay Coordinately Regulate the Human HFE mRNA Levels

Nonsense-mediated decay (NMD) is an mRNA surveillance pathway that selectively recognizes and degrades defective mRNAs carrying premature translation-termination codons. However, several studies have shown that NMD also targets physiological transcripts that encode full-length proteins, modulating their expression. Indeed, some features of physiological mRNAs can render them NMD-sensitive. Human HFE is a MHC class I protein mainly expressed in the liver that, when mutated, can cause hereditary hemochromatosis, a common genetic disorder of iron metabolism. The HFE gene structure comprises seven exons; although the sixth exon is 1056 base pairs (bp) long, only the first 41 bp encode for amino acids. Thus, the remaining downstream 1015 bp sequence corresponds to the HFE 3′ untranslated region (UTR), along with exon seven. Therefore, this 3′ UTR encompasses an exon/exon junction, a feature that can make the corresponding physiological transcript NMD-sensitive. Here, we demonstrate that in UPF1-depleted or in cycloheximide-treated HeLa and HepG2 cells the HFE transcripts are clearly upregulated, meaning that the physiological HFE mRNA is in fact an NMD-target. This role of NMD in controlling the HFE expression levels was further confirmed in HeLa cells transiently expressing the HFE human gene. Besides, we show, by 3′-RACE analysis in several human tissues that HFE mRNA expression results from alternative cleavage and polyadenylation at four different sites – two were previously described and two are novel polyadenylation sites: one located at exon six, which confers NMD-resistance to the corresponding transcripts, and another located at exon seven. In addition, we show that the amount of HFE mRNA isoforms resulting from cleavage and polyadenylation at exon seven, although present in both cell lines, is higher in HepG2 cells. These results reveal that NMD and alternative polyadenylation may act coordinately to control HFE mRNA levels, possibly varying its protein expression according to the physiological cellular requirements

Moulage of facial mask techniques

INTRODUCTION: There are described in the literature several techniques for shaping the face mask in order to develop models for fabrication of maxillofacial prostheses. OBJECTIVE: This article aims to describe two techniques used for facial moulage, the conventional technique and conventional technique with modification, highlighting their advantages and disadvantages. CASE REPORT: In the first technique, the impression material is deposited over the region of interest and then a reinforcement layer of plaster type II is putting to cover the impression material. The modification of the conventional technique begins with a relief with cotton over the facial tissue, applying a layer of plaster type II in order to construct the reinforcement layer and, after its crystallization, the application of impression material over the area to be molded, followed by its plaster mask contention. CONCLUSION: The choice of impression technique and materials used will depend on the ability of the professional. The important thing is to make a moulage in order to get an accurate facial cast for the prosthesis' success.INTRODUÇÃO: Encontram-se descritas na literatura várias técnicas para moldagem da máscara facial com o intuito de obtenção de modelos para confecção de próteses bucomaxilofaciais. OBJETIVO: Este artigo tem como objetivo relatar duas técnicas de moldagem, a técnica convencional e a técnica convencional modificada, ressaltando suas vantagens e desvantagens. TÉCNICA: A primeira técnica consiste na deposição do material de moldagem na região de interesse e, posteriormente, na adição da camada de reforço com gesso tipo II. A modificação da técnica convencional inicia‑se com a realização de um alívio com algodão nos tecidos faciais a serem moldados, a aplicação de uma camada de gesso tipo II para a construção prévia da camada de reforço e, após sua cristalização, a aplicação do material de moldagem sobre a área a ser moldada, seguida de sua contenção por meio da máscara de gesso. CONCLUSÃO: A escolha da técnica de moldagem e dos materiais utilizados dependerá da habilidade do profissional. O importante é realizar uma moldagem que produza um modelo facial sem distorções para o sucesso da prótese

Moulage of facial mask techniques

INTRODUCTION: There are described in the literature several techniques for shaping the face mask in order to develop models for fabrication of maxillofacial prostheses. OBJECTIVE: This article aims to describe two techniques used for facial moulage, the conventional technique and conventional technique with modification, highlighting their advantages and disadvantages. CASE REPORT: In the first technique, the impression material is deposited over the region of interest and then a reinforcement layer of plaster type II is putting to cover the impression material. The modification of the conventional technique begins with a relief with cotton over the facial tissue, applying a layer of plaster type II in order to construct the reinforcement layer and, after its crystallization, the application of impression material over the area to be molded, followed by its plaster mask contention. CONCLUSION: The choice of impression technique and materials used will depend on the ability of the professional. The important thing is to make a moulage in order to get an accurate facial cast for the prosthesis' success.INTRODUÇÃO: Encontram-se descritas na literatura várias técnicas para moldagem da máscara facial com o intuito de obtenção de modelos para confecção de próteses bucomaxilofaciais. OBJETIVO: Este artigo tem como objetivo relatar duas técnicas de moldagem, a técnica convencional e a técnica convencional modificada, ressaltando suas vantagens e desvantagens. TÉCNICA: A primeira técnica consiste na deposição do material de moldagem na região de interesse e, posteriormente, na adição da camada de reforço com gesso tipo II. A modificação da técnica convencional inicia&#8209;se com a realização de um alívio com algodão nos tecidos faciais a serem moldados, a aplicação de uma camada de gesso tipo II para a construção prévia da camada de reforço e, após sua cristalização, a aplicação do material de moldagem sobre a área a ser moldada, seguida de sua contenção por meio da máscara de gesso. CONCLUSÃO: A escolha da técnica de moldagem e dos materiais utilizados dependerá da habilidade do profissional. O importante é realizar uma moldagem que produza um modelo facial sem distorções para o sucesso da prótese.43844

Selective albumin-binding surfaces modified with a thrombin-inhibiting peptide

Blood-contacting medical devices have been associated with severe clinical complications, such as thrombus formation, triggered by the activation of the coagulation cascade due to the adsorption of certain plasma proteins on the surface of biomaterials. Hence, the coating of such surfaces with antithrombotic agents has been used to increase biomaterial haemocompatibility. Biomaterial-induced clotting may also be decreased by albumin adsorption from blood plasma in a selective and reversible way, since this protein is not involved in the coagulation cascade. In this context, this paper reports that the immobilization of the thrombin inhibitor D-Phe-Pro-D-Arg-D-Thr-CONH2 (fPrt) onto nanostructured surfaces induces selective and reversible adsorption of albumin, delaying the clotting time when compared to peptide-free surfaces. fPrt, synthesized with two glycine residues attached to the N-terminus (GGfPrt), was covalently immobilized onto self-assembled monolayers (SAMs) having different ratios of carboxylate-hexa(ethylene glycol)- and tri(ethylene glycol)-terminated thiols (EG6-COOH/EG3) that were specifically designed to control GGfPrt orientation, exposure and density at the molecular level. In solution, GGfPrt was able to inactivate the enzymatic activity of thrombin and to delay plasma clotting time in a concentration-dependent way. After surface immobilization, and independently of its concentration, GGfPrt lost its selectivity to thrombin and its capacity to inhibit thrombin enzymatic activity against the chromogenic substrate n-p-tosyl-Gly-Pro-Arg-p-nitroanilide. Nevertheless, surfaces with low concentrations of GGfPrt could delay the capacity of adsorbed thrombin to cleave fibrinogen. In contrast, GGfPrt immobilized in high concentrations was found to induce the procoagulant activity of the adsorbed thrombin. However, all surfaces containing GGfPrt have a plasma clotting time similar to the negative control (empty polystyrene wells), showing resistance to coagulation, which is explained by its capacity to adsorb albumin in a selective and reversible way. This work opens new perspectives to the improvement of the haemocompatibility of blood-contacting medical devices

Acidentes causados pela arraia fluvial Potamotrygon motoro em comunidades lacustres em Território do bioma Oriental da Amazônia

The injuries caused by freshwater stingrays are common among fishermen. The raya Potamotrygon motoro en the features a stinger with a sharp edge and serrated tips spread bilaterally, the stingers have toxins that promote vasoconstriction, causing immediate pain and ischemia. These accidents extensive and could keep victims unable to work from weeks to months. Considering the impact the injuries in riparian fishing communities’ livelihoods, this study aimed to analyze reports of envenomation caused by the freshwater stingray Potamotrygon motoro in two municipalities localizate in the Eastern Amazon biome territory (Baixada Maranhense Ramsar site) in the municipality of Penalva and Viana. The methodology consisted in analyses descriptive and transversal, troght of the application of 40 semi-structured questionnaire in artisanal fishermen in order to obtain clinical and epidemiological data related to the accidents caused for P. motoro in fissherman artisanal. Forty fishers injured by freshwater stingrays were interviewed. Pain and edema were the symptoms common to all fishermen, followed by skin necrosis (70%). Victims often adopt unusual self-treatments, based on traditional and cultural knowledge, such as the use of urine, herbs, smoke of burlap bags and human feces. The number of injuries in each fisherman varied from 2 to 4 times (50%) to up to 10 times (12.5%). The results show that injuries caused by P. motoro are frequent in Penalva and Viana, reinforcing the need for public health agencies to establish preventive educational actions and provide better qualification for health professionals to perform the appropriate treatment for the injuries. Keywords: Animals poisonous. Fish. Occupational health. Environmental health.Os ferimentos causados por arraias de água doce são comuns entre os pescadores. A raia Potamotrygon motoro apresenta um ferrão com uma ponta afiada e pontas serrilhadas espalhadas bilateralmente, os ferrões possuem toxinas que promovem a vasoconstrição, causando dor imediata e isquemia. Esses acidentes são extensos e podem manter as vítimas impossibilitadas de trabalhar por semanas a meses. Considerando o impacto das injúrias na subsistência de comunidades ribeirinhas de pescadores, este estudo teve como objetivo analisar relatos de envenenamento pela arraia Potamotrygon motoro em dois municípios localizados no bioma Amazônia Oriental (sítio Ramsar da Baixada Maranhense) no município de Penalva e Viana. A metodologia consistiu em análises descritivas e transversais, a partir da aplicação de 40 questionários semiestruturados em pescadores artesanais a fim de obter dados clínicos e epidemiológicos relacionados aos acidentes causados por P. motoro em pescadores artesanais. Quarenta pescadores feridos por arraias de água doce foram entrevistados. Dor e edema foram os sintomas comuns a todos os pescadores, seguidos de necrose cutânea (70%). As vítimas costumam adotar auto tratamentos inusitados, baseados em conhecimentos tradicionais e culturais, como o uso de urina, ervas, fumaça de saco de estopa e fezes humanas. O número de lesões em cada pescador variou de 2 a 4 vezes (50%) a até 10 vezes (12,5%). Os resultados mostram que as lesões por P. motoro são frequentes em Penalva e Viana, reforçando a necessidade dos órgãos públicos de saúde estabelecerem ações educativas preventivas e proporcionarem melhor qualificação dos profissionais de saúde para realizar o tratamento adequado das lesões. Palavras-chave: Animais venenosos. Raias. Saúde ocupacional. Saúde ambiental

AVALIAÇÃO DA QUALIDADE DAS ÁGUAS SUPERFICIAIS DO RIO JAMARI NA REGIÃO DA CONSTRUÇÃO DE UMA PCH NO MUNICÍPIO DE MONTE NEGRO-RONDÔNIA, AMAZÔNIA OCIDENTAL

http://dx.doi.org/10.5902/223611707295With the construction of a SHP (small hydro) in the course of the Jamari River in the town ofMonte Negro - RO becomes important monitoring of surface waters of the Rio Jamari to assessyour current situation during the process of implementing the SHP to subsequently assess theimpact caused the river by construction. The present paper has aimed at the evaluation of thewater quality of the Rio Jamari, evaluating standards physico-chemical, microbiological,phytoplankton and ichthyoplankton, where after evaluating all the parameters generated up theWQI (Water Quality Index), which was between 68-79%, assessed at four points in the course ofthe river, indicating a good quality water, within the parameters of evaluable IQA. The values obtained were considered satisfactory in view of the Jamari River is a river that has suffered a lotfrom the process of deforestation in the region, deploying mines and plantations.http://dx.doi.org/10.5902/223611707295Com a construção de uma PCH (pequenas centrais hidrelétricas) no curso do Rio Jamari na cidade de Monte Negro – RO torna-se importante o monitoramento das águas superficiais do Rio Jamari, para avaliar sua atual situação durante o processo de implantação da PCH, para posteriormente avaliar-se o impacto causado ao rio pela construção. Neste intuito o presente artigo trata da avaliação da qualidade da água do Rio Jamari, avaliando-se padrões físico-químicos, microbiológicos, fitoplâncton e ictioplâncton, onde após avaliar todos os parâmetros gerou-se o IQA (Índice da Qualidade de Água), que ficou entre 68 a 79%, nos quatro pontos avaliados no curso do Rio, indicando uma água com qualidade boa, dentro dos parâmetros avaliáveis do IQA. Os valores obtidos foram considerados satisfatórios, tendo em vista que o Rio Jamari é um rio que sofreu muito com os processos de desmatamento da região, garimpos e implantação de lavouras as margens