Deception Island is an active volcano in the Antarctica being volcanism a source of mercury. To improve the understanding of the Hg cycle in this remote ecosystem, pyroclastic gravel and water samples were collected and total (THg) and monomethylmercury (MMHg) concentrations were measured as well as the potential for Hg methylation. Gravel samples collected close to active fumaroles showed the highest THg levels (72 ng/g) while in water samples the highest concentrations of THg (1.2 ng/L) and MMHg (0.45 ng/L) where found. Methylation activity was barely observable in gravel samples. Biotic methylation rates in water were up to 13 times higher compared to those recorded previously in other polar waters. Abiotic methylation processes also play an important role, with up to 0.54 ± 0.43% of added Hg converted instantaneously to MMHg. These results suggest that Deception Island presents favourable conditions for MMHg explaining the elevated concentrations of both THg and MMHg in this ecosystem.The operation of coastal nuclear power plants and thermal power plants (CNATPPs) can cause regional sea surface temperature (SST) increases. To assess their effects on coastal ecosystems, the scope and extent of their impacts must be understood. We aimed to quantitatively assess the SST increases caused by thermal discharge under climate warming by comparing SSTs between control and test groups and among different offshore buffer zones based on daily MODIS SST data from 2002 to 2017. The results showed that (1) a good correlation occurred between the CNATPP installed capacity and SST increase in the 0-2 km offshore waters; (2) the SST increase caused by thermal discharge was the largest in summer and the smallest in winter; and (3) the effect of thermal discharge occurred within 2 km offshore when the installed capacity exceeded 2000 MW and extended to 5 km when it reaches more than 4000 MW.Habitat restoration is an international priority. With this demand there is a need for ecological knowledge to underpin restoration projects to ensure their success and cost-effective delivery. This study is the first temperate marine restoration project to examine the role seasonality and location may have on restoration projects. The study found that the settlement of Serpula vermicularis, a rare biogenic reef forming species of conservation importance, was up to three times higher on materials deployed during July than other months. The results also found similar differences in settlement between restoration sites. These results suggest that the timing and location of a restoration effort could affect its overall success in the medium to long term. For the restoration of marine biogenic species of conservation importance, targeted spatial and temporal pre-restoration experiments can greatly increase a project's chance of success as well as making large-scale restoration programs more cost efficient.Sea turtles are useful sentinels to monitor the dissemination of antimicrobial resistance (AMR) in the marine coastal ecosystems. Forty Gram negative bacteria were isolated from wounds of 52 injured Caretta caretta, living in the Mediterranean Sea. https://www.selleckchem.com/products/ng25.html Bacteria were identified using 16S rRNA gene sequencing and tested for susceptibility to 15 antibiotics. In addition, NGS amplicon sequencing was performed to detect the presence of AmpC β-lactamase genes (blaAmpC) and extended-spectrum β-lactamase (ESBL) genes (blaCTX-M,blaSHV,blaTEM). Seventy-five percent of the isolates (30/40 isolates) exhibited multidrug resistance (MDR) phenotypes and 32.5% (13/40 isolates) were confirmed to be positive for at least one gene. The variants of ESBLs genes were blaCTX-M-3,blaTEM-236 and blaSHV-12. Variants of the blaAmpCβ-lactamase gene i.e., blaACT-24, blaACT-2, blaACT-17, blaDHA-4 and blaCMY-37, were also detected. In addition, 4 isolates were found simultaneously harboring CTX and AmpC genes while 2 strains harbored 3 genes (blaACT-2+TEM-236+SHV-12, and blaCTX-M-3+ACT-24+TEM-236).Salinity is an important ecological factor that affects physiological metabolism, survival, and distribution of marine organisms. Despite changes in the osmolarity and composition of the cytosol during salinity shifts, marine mollusks are able to maintain their metabolic function. The razor clam (Sinonovacula constricta) survives the wide range of salinity in the intertidal zone via changes in behavior and physiology. To explore the stress responses and mechanisms of salinity tolerance in razor clams, we collected transcriptomic and metabolomic data from a control group (salinity 20‰, S20) and a salinity-stress group (salinity 35‰, S35). The transcriptome data showed that genes related to the immune system, cytoskeleton remodeling, and signal transduction pathways dominated in the S35 group to counteract hypersalinity stress in the gill. The metabolomic analysis showed that 142 metabolites were significantly different between the S35 and S20 groups and that amino acid and carbohydrate metabolism were affected by hypersalinity stress. Levels of amino acids and energy substances, such as l-proline, isoleucine, and fructose, were higher in the gill of the S35 group. The combination of transcriptomic and metabolomic data indicated that metabolism of amino acids, carbohydrates, and lipids was enhanced in the gill during adaptation to high salinity. These results clarified the complex physiological processes involved in the response to hyperosmotic stress and maintenance of metabolism in the gill of razor clams. These findings provide a reference for further study of the biological responses of euryhaline shellfish to hyperosmotic stress and a molecular basis for the search for populations with high salinity tolerance.Semaphorins and Plexins constitute one of the largest family of guidance molecules and receptors involved in setting critical biological steps for central nervous system development. The role of these molecules in axonal development has been extensively characterized but Semaphorins and Plexins are also involved in a variety of other developmental processes, spanning from cell polarization to migration, laminar segregation and neuronal maturation. In this review, we aim to gather discoveries carried in the field of neurodevelopment over the last decade, during which Semaphorin/Plexin complexes have emerged as key regulators of neurogenesis, neural cell migration and adult gliogenesis. As well, we report mechanisms that brought a better understanding of axonal midline crossing.
Deception Island is an active volcano in the Antarctica being volcanism a source of mercury. To improve the understanding of the Hg cycle in this remote ecosystem, pyroclastic gravel and water samples were collected and total (THg) and monomethylmercury (MMHg) concentrations were measured as well as the potential for Hg methylation. Gravel samples collected close to active fumaroles showed the highest THg levels (72 ng/g) while in water samples the highest concentrations of THg (1.2 ng/L) and MMHg (0.45 ng/L) where found. Methylation activity was barely observable in gravel samples. Biotic methylation rates in water were up to 13 times higher compared to those recorded previously in other polar waters. Abiotic methylation processes also play an important role, with up to 0.54 ± 0.43% of added Hg converted instantaneously to MMHg. These results suggest that Deception Island presents favourable conditions for MMHg explaining the elevated concentrations of both THg and MMHg in this ecosystem.The operation of coastal nuclear power plants and thermal power plants (CNATPPs) can cause regional sea surface temperature (SST) increases. To assess their effects on coastal ecosystems, the scope and extent of their impacts must be understood. We aimed to quantitatively assess the SST increases caused by thermal discharge under climate warming by comparing SSTs between control and test groups and among different offshore buffer zones based on daily MODIS SST data from 2002 to 2017. The results showed that (1) a good correlation occurred between the CNATPP installed capacity and SST increase in the 0-2 km offshore waters; (2) the SST increase caused by thermal discharge was the largest in summer and the smallest in winter; and (3) the effect of thermal discharge occurred within 2 km offshore when the installed capacity exceeded 2000 MW and extended to 5 km when it reaches more than 4000 MW.Habitat restoration is an international priority. With this demand there is a need for ecological knowledge to underpin restoration projects to ensure their success and cost-effective delivery. This study is the first temperate marine restoration project to examine the role seasonality and location may have on restoration projects. The study found that the settlement of Serpula vermicularis, a rare biogenic reef forming species of conservation importance, was up to three times higher on materials deployed during July than other months. The results also found similar differences in settlement between restoration sites. These results suggest that the timing and location of a restoration effort could affect its overall success in the medium to long term. For the restoration of marine biogenic species of conservation importance, targeted spatial and temporal pre-restoration experiments can greatly increase a project's chance of success as well as making large-scale restoration programs more cost efficient.Sea turtles are useful sentinels to monitor the dissemination of antimicrobial resistance (AMR) in the marine coastal ecosystems. Forty Gram negative bacteria were isolated from wounds of 52 injured Caretta caretta, living in the Mediterranean Sea. https://www.selleckchem.com/products/ng25.html Bacteria were identified using 16S rRNA gene sequencing and tested for susceptibility to 15 antibiotics. In addition, NGS amplicon sequencing was performed to detect the presence of AmpC β-lactamase genes (blaAmpC) and extended-spectrum β-lactamase (ESBL) genes (blaCTX-M,blaSHV,blaTEM). Seventy-five percent of the isolates (30/40 isolates) exhibited multidrug resistance (MDR) phenotypes and 32.5% (13/40 isolates) were confirmed to be positive for at least one gene. The variants of ESBLs genes were blaCTX-M-3,blaTEM-236 and blaSHV-12. Variants of the blaAmpCβ-lactamase gene i.e., blaACT-24, blaACT-2, blaACT-17, blaDHA-4 and blaCMY-37, were also detected. In addition, 4 isolates were found simultaneously harboring CTX and AmpC genes while 2 strains harbored 3 genes (blaACT-2+TEM-236+SHV-12, and blaCTX-M-3+ACT-24+TEM-236).Salinity is an important ecological factor that affects physiological metabolism, survival, and distribution of marine organisms. Despite changes in the osmolarity and composition of the cytosol during salinity shifts, marine mollusks are able to maintain their metabolic function. The razor clam (Sinonovacula constricta) survives the wide range of salinity in the intertidal zone via changes in behavior and physiology. To explore the stress responses and mechanisms of salinity tolerance in razor clams, we collected transcriptomic and metabolomic data from a control group (salinity 20‰, S20) and a salinity-stress group (salinity 35‰, S35). The transcriptome data showed that genes related to the immune system, cytoskeleton remodeling, and signal transduction pathways dominated in the S35 group to counteract hypersalinity stress in the gill. The metabolomic analysis showed that 142 metabolites were significantly different between the S35 and S20 groups and that amino acid and carbohydrate metabolism were affected by hypersalinity stress. Levels of amino acids and energy substances, such as l-proline, isoleucine, and fructose, were higher in the gill of the S35 group. The combination of transcriptomic and metabolomic data indicated that metabolism of amino acids, carbohydrates, and lipids was enhanced in the gill during adaptation to high salinity. These results clarified the complex physiological processes involved in the response to hyperosmotic stress and maintenance of metabolism in the gill of razor clams. These findings provide a reference for further study of the biological responses of euryhaline shellfish to hyperosmotic stress and a molecular basis for the search for populations with high salinity tolerance.Semaphorins and Plexins constitute one of the largest family of guidance molecules and receptors involved in setting critical biological steps for central nervous system development. The role of these molecules in axonal development has been extensively characterized but Semaphorins and Plexins are also involved in a variety of other developmental processes, spanning from cell polarization to migration, laminar segregation and neuronal maturation. In this review, we aim to gather discoveries carried in the field of neurodevelopment over the last decade, during which Semaphorin/Plexin complexes have emerged as key regulators of neurogenesis, neural cell migration and adult gliogenesis. As well, we report mechanisms that brought a better understanding of axonal midline crossing.
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