GEOTRACES Buck, Clifton S.; Fietz, Susanne; Hamilton, Douglas S. ...
Oceanography (Washington, D.C.),
06/2024, Letnik:
37, Številka:
2
Journal Article
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The international GEOTRACES program has allowed unprecedented access to aerosols in the remote marine environment, moved the community toward standardized methodologies, and contributed to expanding ...research capabilities around the globe. A key aspect of GEOTRACES aerosol research is the quantification of deposition fluxes of trace elements and isotopes to the surface ocean as a source for biolimiting nutrients and anthropogenic contaminants. New methods for quantifying flux have been developed that leverage radioisotope tracers in the surface ocean to estimate bulk deposition rates on longer and more relevant timescales. The question as to what fraction of aerosols is soluble remains and is a source of continuing uncertainty. To that end, the community has engaged in coordinated study to address questions regarding the fractional solubility of aerosol trace elements and isotopes through the evaluation of widely used dissolution and extraction techniques. Intercalibration efforts, method standardization, and normalization of open-access data archiving will be the legacy of GEOTRACES-era aerosol research.
Western boundary currents (WBCs) adjacent to subtropical continental shelves (STCSs; between ~25° and 35° latitude; Figure 1) transport heat, nutrients, and biota poleward along the western margins ...of major ocean basins, interacting with the continental margins and influencing their physics and biology. Eddies and meanders along the shelf edge upwell deep, nutrient-laden water that can be advected onto the adjacent shelves with a corresponding export of particle-rich shelf water (e.g., Lee et al., 1991; Kimura et al., 1997; Campos et al., 2000; Roughan and Middleton, 2002, 2004; Lutjeharms, 2006; Savidge and Savidge, 2014). Despite their similarities, the various STCS regions display key differences with respect to boundary current strength and variability, shelf width and geometry, and trophic structure. Comparative analyses of the physical forcing and biological responses among STCS have the potential to reveal common underlying properties, forcing mechanisms, and sensitivities to climatic perturbations that are not possible to elucidate with region-specific studies. This kind of fundamental understanding of relationships between physics and biological responses is critical to predicting consequences of environmental change across a wide range of spatiotemporal scales.
Dissolved oxygen (DO) is essential for the survival of most aquatic organisms. Hypoxia, defined as a DO concentration of less than 2 mg L–1, is a significant issue for ecosystems in estuaries and ...coastal waters and is one of the top themes of the United Nations Decade of Ocean Science for Sustainable Development (2021–2030). An area off the Yangtze River Estuary (YRE), China, annually develops one of the world ocean’s largest hypoxic areas. Observations collected by ship since 1999, and by long-term sensors since 2009, show that DO concentration in this region has been both declining and greatly fluctuating.
Bacillus species constitute a diverse group of bacteria widely distributed in soil and the aquatic environment. In this study, Bacillus strains isolated from the coastal environment of Cochin, India ...were identified by detailed conventional biochemical methods, fatty acid methyl ester (FAME) analysis and partial 16S rDNA sequencing. Analysis of the data revealed that Bacillus pumilus was the most predominant species in the region under study followed by B. cereus and B. sphaericus. The B. pumilus isolates were further characterized by arbitrarily primed PCR (AP-PCR), antibiotic sensitivity profiling and PCR screening for known toxin genes associated with Bacillus spp. All B. pumilus isolates were biochemically identical, exhibited high protease and lipase activity and uniformly sensitive to antibiotics tested in this study. One strain of B. pumilus harboured cereulide synthetase gene cesB of B. cereus which was indistinguishable from rest of the isolates biochemically and by AP-PCR. This study reports, for the first time, the presence of the emetic toxin gene cesB in B. pumilus.
As espécies de Bacillus constituem um grupo diversificado de bactérias amplamente distribuídas no solo e no ambiente aquático. Neste estudo, cepas de Bacillus isoladas do ambiente costeiro de Cochin, Índia, foram identificadas através de métodos bioquímicos convencionais, análise de ésteres metílicos de ácidos graxos (FAME) e sequenciamento de 16S rDNA. A análise dos dados revelou que Bacillus pumilus foi a espécie predominante na região estudada, seguido de B. cereus e B. sphaericus. Os isolados de B. pumilus foram caracterizados através da reação em cadeia da polimerase com primers arbitrários (AP-PCR), perfil de sensibilidade a antibióticos e triagem por PCR de genes de toxinas associadas com Bacillus spp. Todos os isolados de B. pumilus foram bioquimicamente idênticos, apresentaram elevada atividade de protease e lipase e foram uniformemente sensíveis aos antibióticos estudados. Um dos isolados de B. pumilus apresentou o gene cesB de B. cereus, que não foinão distinguível dos demais isolados por testes bioquímicos nem por AP-PCR. Este é o primeiro relato da presença do gene cesB da toxina eméticaem B. pumilus.
DESIGN UPDATE TO Lowin, Benjamin; Izett, Robert; Taylor, Edward ...
Oceanography (Washington, D.C.),
06/2024, Letnik:
37, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Measuring net community production (NCP) is a challenging, yet important, aspect of oceanography. Methods based on discrete sample collection often have low spatial and temporal resolution, while ...expensive instruments are required to obtain continuous NCP measurements at high resolution. To address these issues, Izett and Tortell (2020) created a novel, autonomous system called the Pressure of In-situ Gases Instrument (PIGI) and shared their design with the community. The system yields high-resolution surface water O2 and N2 measurements that are used to estimate NCP along a ship transect or at a fixed field station. This article provides a description of an updated PIGI system that was tested in a series of cruises in the coastal South Atlantic Bight (SAB). The data collected suggest that it performs equally as well as the original, providing high spatial resolution NCP measurements. Unfortunately, we believe that the SAB coastal and estuaries violate the steady state assumption due to horizontal mixing driven by tidal forces. Thus, we cannot recommend the PIGI system for use in the coastal SAB, but we encourage its use in open ocean waters that do not violate the assumptions on which this system was built. We document the updates to the PIGI system, share tips and tricks on its use, and discuss the data collected.
Lipases (triacylglycerol acylhydrolases EC 3.1.1.3) are water-soluble enzymes. They catalyze the hydrolysis of fats and oils. A cold-active lipase from marine Bacillus cereus HSS, isolated from the ...Mediterranean Sea, Alexandria, Egypt, was purified and characterized. The total purification depending on lipase activity was 438.9 fold purification recording 632 U/mg protein. The molecular weight of the purified lipase was estimated to be 65 kDa using sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The optimum substrate concentration, enzyme concentration, pH, and temperature were 1.5 mM, 100 μl, pH 6 and 10℃, respectively. The lipase was tolerant to NaCl concentrations ranging from 1.5 to 4.5%. The lipase was affected by the tested metal ions, and its activity was inhibited by 16% in the presence of 0.05 M SDS. The application of the cold-active lipase for the removal of an oil stain from a white cotton cloth showed that it is a promising biological agent for the treatment of oily wastes and other related applications. To the best of our knowledge, this is the first report of the purification and characterization of a lipase from marine B. cereus HSS isolated from the Mediterranean Sea. KCI Citation Count: 0
The current study investigates the phytochemical and pharmaceutical activities of
Sargassium vulgare
(SVE) collected from the Suez Canal. The prescreening using cytotoxicity was tested against ...hepatocellular carcinoma cell lines. Furthermore the SVE inhibit cell growth effectively with IC50 = 20.8 µg/ml. The pharmacological studies revealed high antioxidant capacity at all examined concentrations. On the meantime, anticancer assay carried out using tyrosine kinase (PTK) and sphingosine kinase 1 inhibitor screening assays revealed inhibition with 75.73 and 80.01%; respectively. Furthermore, the anti-inflammatory profiling revealed that the activities against COX1, COX2, IL6 and TNF were 77.39, 88.35, 75.38 and 71.24%; respectively. Additionally, the anti-Alzheimer results showed high activity at 1 mg with 76.33%. Finally the antiviral activities using reverse transcriptase inhibition assay give 92.24%. Consequently, it can be easily conclude that the SVE collected from the Suez Canal are excellent source of natural products for nutritional and pharmaceutical applications.
Molecular Characterization of Cold-inducible β-Galactosidase from Arthrobacter sp. ON14 Isolated from Antarctica Xu, Ke, Xiamen University, Xiamen, P. R. China; Tang, Xixiang, Xiamen University, Xiamen, P. R. China; Gai, Yingbao, Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, P. R. China ...
Journal of microbiology and biotechnology,
03/2011, Letnik:
21, Številka:
3
Journal Article
Recenzirano
A psychrotrophic bacterium, Arthrobacter sp. ON14, isolated from Antarctica, was shown to exhibit a high β-galactosidase activity at a low temperature. A genomic library of ON14 was constructed and ...screened for β-galactosidase genes on functional plates containing 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) as the substrate. Two different β-galactosidase genes, named as galA, gal B, were found in ON14. Computational analyses of the genes revealed that the encoded protein GalA belongs to family 2 of glycosyl hydrolysases and is a cold-active protein, whereas GalB belongs to family 42 of glycosyl hydrolysases and is a mesophilic protein. Reverse transcription analyses revealed that the expression of galA is highly induced at a low temperature (4℃) and repressed at a high temperature (28℃) when lactose is used as the sole carbon source. Conversely, the expression of galB is inhibited at a low temperature and induced at a high temperature. The purified GalA showed its peak activity at 15℃ and pH 8. The mineral ions Na+, K+, Mg²+, and Mn²+ were identified as enzyme activators, whereas Ca²+ had no influence on the enzyme activity. An enzyme stability assay revealed that the activity of GalA is significantly decreased when it is incubated at 45℃ for 2 h, and all its activity is lost when it is incubated at 50℃.
Bacterial strain
BT21 isolated from marine sediments was found to produce extracellular xylanase. The
gene encoding xylanase enzyme was cloned and expressed in
. The gene encoded a protein consisting ...of 213 amino acid residues with calculated molecular mass of 23.3 kDa. Purified recombinant xylanase had optimum activity at 60 °C and pH=6. The enzyme was highly stable in alkaline pH, at pH=7 it remained 100% active for 24 h, while its activity increased at pH=8 and 9 during incubation.
BT21 xylanase had alkaline pI of 9.4 and belongs to glycosyl hydrolase family 11. The mode of action of XynBT21 on beechwood xylan and xylooligosaccharides was studied. It hydrolysed xylooligosaccharides and beechwood xylan yielding mainly xylobiose (X
) with a small amount of xylose (X
), indicating that XynBT21 was probably an endo-acting xylanase. Enzymatic hydrolysis using wheat bran as a substrate revealed that xylanase reported here has the potential to produce xylobiose from wheat bran. Xylooligosaccharides, especially xylobiose, have strong bifidogenic properties and are increasingly used as a prebiotic. This is the first report that describes this novel xylanase enzyme from marine
BT21 used for the release of xylobiose from wheat bran.
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