Isolation, characterization, and hydrolytic activities of Geobacillus species from Jordanian hot springs

The present study was conducted to isolate, identify, characterize and to determine the enzymatic activities of the thermophilic Geobacillus species from five Jordanian hot springs. Based on phenotypic characters, eight thermophilic isolates were identified and belonged to the genus Geobacillus. The Geobacillus isolates were abundant in all investigated hot springs. The optimal temperature for growth of the isolates was 60 to 65°C and the optimal pH was 6 to 8. Colonies were light yellow circular to rhizoid. The bacterial cells were Gram positive rods and endospore forming. All isolates produced amylase, caseinase, alkaline and acid phosphatases, esterase (C4), esterase lipase (C8), α-Galactosidase, β-Glucuronidase, β-Glucosidase, and N-Acetyl-β-glucosaminidase. Seven isolates produced leucine and valine arylamidases and five isolates produced naphthol-AS-B1- phsphohydrolase. Lipase (C14) activity from two isolates and α-chymotrypsin activity from three isolates were also detected. The phenotypic characterization of those isolates was confirmed by genotypic method using 16S rDNA sequence analysis. Maximal homology of all eight  isolates to genus Geobacillus was observed. Five of these isolates showed greater than 98% homology with Geobacillus stearothermophilus and one isolate showed 100% homology with Geobacillus thermoglucosidasius. Therefore, 16S rRNA gene sequence analysis can be considered as a valuable genotypic tool for the identification and characterization of thermophilic bacteria at genus level. Moreover, enzymatic products of those isolates could receive considerable attention due to their potential applications in biotechnology.Keywords: Thermophiles, Geobacillus, hydrolytic enzymes, hot spring, 16S rRNA

Effect of Various Local Anthropogenic Impacts on the Diversity of Coral Mucus-Associated Bacterial Communities

The global continued decline in coral reefs is intensifying the need to understand the response of corals to local environmental stressors. Coral-associated bacterial communities have been suggested to have a swift response to environmental pollutants. This study aims to determine the variation in the bacterial communities associated with the mucus of two coral species, Pocillopora damicornis (Linnaeus, 1758) and Stylophora pistillata (Esper, 1792), and the coral-surrounding seawater from three areas exposed to contamination at the Jordanian coast of the Gulf of Aqaba (Red Sea), and also explores the antibacterial activity of these bacteria. Corals were collected from three contaminated zones along the coast, and the bacteria were quantified and identified by conventional morphological and biochemical tests, as well as 16S rRNA gene sequencing. The average number of bacteria significantly varied among the coral mucus from the sampling zones and between the coral mucus and the surrounding seawater. The P. damicornis mucus-associated bacterial community was dominated by members of the classes Gammaproteobacteria, Cytophagia, and Actinomycetia, while the mucus of S. pistillata represented higher bacterial diversity, with the dominance of the bacterial classes Gammaproteobacteria, Actinomycetia, Alphaproteobacteria, and Bacilli. The effects of local anthropogenic impacts on coral mucus bacterial communities were represented in the increased abundance of bacterial species related to coral diseases. Furthermore, the results demonstrated the existence of bacterial isolates with antibacterial activity that possibly acted as a first line of defense to protect and maintain the coral host against pathogens. Indeed, the dynamics of coral-associated microbial communities highlight the importance of holistic studies that focus on microbial interactions across the coral reef ecosystem

Climate change promotes parasitism in a coral symbiosis.

Coastal oceans are increasingly eutrophic, warm and acidic through the addition of anthropogenic nitrogen and carbon, respectively. Among the most sensitive taxa to these changes are scleractinian corals, which engineer the most biodiverse ecosystems on Earth. Corals' sensitivity is a consequence of their evolutionary investment in symbiosis with the dinoflagellate alga, Symbiodinium. Together, the coral holobiont has dominated oligotrophic tropical marine habitats. However, warming destabilizes this association and reduces coral fitness. It has been theorized that, when reefs become warm and eutrophic, mutualistic Symbiodinium sequester more resources for their own growth, thus parasitizing their hosts of nutrition. Here, we tested the hypothesis that sub-bleaching temperature and excess nitrogen promotes symbiont parasitism by measuring respiration (costs) and the assimilation and translocation of both carbon (energy) and nitrogen (growth; both benefits) within Orbicella faveolata hosting one of two Symbiodinium phylotypes using a dual stable isotope tracer incubation at ambient (26 °C) and sub-bleaching (31 °C) temperatures under elevated nitrate. Warming to 31 °C reduced holobiont net primary productivity (NPP) by 60% due to increased respiration which decreased host %carbon by 15% with no apparent cost to the symbiont. Concurrently, Symbiodinium carbon and nitrogen assimilation increased by 14 and 32%, respectively while increasing their mitotic index by 15%, whereas hosts did not gain a proportional increase in translocated photosynthates. We conclude that the disparity in benefits and costs to both partners is evidence of symbiont parasitism in the coral symbiosis and has major implications for the resilience of coral reefs under threat of global change

Uptake of alkaline earth metals in Alcyonarian spicules (Octocorallia)

Alcyonarian corals (Octocorallia) living in shallow tropical seas produce spicules of high-Mg calcite with ∼13 mol% MgCO3. We cultured the tropical alcyonarian coral Rhythisma fulvum in experiments varying temperature (19–32 °C) and pH (8.15–8.44). Alkalinity depletion caused by spicule formation systematically varied in the temperature experiments increasing from 19 to 29 °C. Spicules were investigated for their elemental ratios (Mg/Ca, Sr/Ca) using ICP-OES, δ44/40Ca using TIMS, as well as δ18O and δ13C by IRMS. Mg/Ca increased with temperature from 146 to 164 mmol/mol, in good agreement with the range observed for marine inorganic calcite. Mg/Ca increased by 1.0 ± 0.4 mmol/mol/°C, similar to the sensitivity of Miliolid foraminifera. The pH experiments revealed a linear relationship between Mg/Ca and carbonate ion concentration of +0.03 ± 0.02 mmol/mol/μMol. Sr/Ca ranges from 2.5 to 2.9 mmol/mol being in good agreement with other high-Mg calcites. Temperature and pH experiments showed linear dependencies of Sr/Ca matching inorganic calcite trends and pointing to a decoupling of crystal precipitation rate and calcification rate. Ca isotopes range between 0.7‰ and 0.9‰ in good agreement with aragonitic scleractinian corals and calcitic coccoliths. Presumably Ca isotopes are fractionated by a biological mechanism that may be independent of the skeletal mineralogy. We observe no temperature trend, but a significant decrease of δ44/40Ca with increasing pH. This inverse correlation may characterise biologically controlled intracellular calcification. Oxygen isotope ratios are higher than expected for isotopic equilibrium with a temperature sensitivity of −0.15 ± 0.03‰/°C. Carbon isotope ratios are significantly lower than expected for equilibrium and positively correlated with temperature with a slope of 0.20 ± 0.04‰/°C. Many of our observations on trace element incorporation in R. fulvum may be explained by inorganic processes during crystal formation, which do not comply with the intracellular mode of calcification in Alcyonarian corals. The observed elemental and isotopic compositions, however, could be explained if the partitioning caused by biological mechanisms mimics the effects of inorganic processes

In Situ Oxygen Dynamics in Coral-Algal Interactions

Background: Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration. Methods/Findings: We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA). Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300-400 μM during the day. At night, the interface was hypoxic (~70 μM) in coral-turf interactions and close to anoxic (~2 μM) in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL) was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively. Conclusions/Significance: Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons). Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of microenvironmental conditions in studies on coral stress. © 2012 Wangpraseurt et al

Hypofibrinolysis in diabetes: a therapeutic target for the reduction of cardiovascular risk

An enhanced thrombotic environment and premature atherosclerosis are key factors for the increased cardiovascular risk in diabetes. The occlusive vascular thrombus, formed secondary to interactions between platelets and coagulation proteins, is composed of a skeleton of fibrin fibres with cellular elements embedded in this network. Diabetes is characterised by quantitative and qualitative changes in coagulation proteins, which collectively increase resistance to fibrinolysis, consequently augmenting thrombosis risk. Current long-term therapies to prevent arterial occlusion in diabetes are focussed on anti-platelet agents, a strategy that fails to address the contribution of coagulation proteins to the enhanced thrombotic milieu. Moreover, antiplatelet treatment is associated with bleeding complications, particularly with newer agents and more aggressive combination therapies, questioning the safety of this approach. Therefore, to safely control thrombosis risk in diabetes, an alternative approach is required with the fibrin network representing a credible therapeutic target. In the current review, we address diabetes-specific mechanistic pathways responsible for hypofibrinolysis including the role of clot structure, defects in the fibrinolytic system and increased incorporation of anti-fibrinolytic proteins into the clot. Future anti-thrombotic therapeutic options are discussed with special emphasis on the potential advantages of modulating incorporation of the anti-fibrinolytic proteins into fibrin networks. This latter approach carries theoretical advantages, including specificity for diabetes, ability to target a particular protein with a possible favourable risk of bleeding. The development of alternative treatment strategies to better control residual thrombosis risk in diabetes will help to reduce vascular events, which remain the main cause of mortality in this condition

THE EFFECTS OF VEGETABLE LECITHIN ON SOME SANGUINE BIOCHEMICAL PARAMETERS AT LACTATING SHEEP AND GOATS

From a complex experiment of establishing the effects of lecithin supplemented in the diet of small ruminants, in this paper we present the influence of lecithin on some sanguine biochemical parameters at lactating sheep and goat. The researches were made on a experimental group formed by 5 sheep from łurcana breed and 5 goats from Crapatina breed, which were fed in the first experimental period with a base ratio (Br) formed by 1.5 kg of hill hay and 0.2 kg concentrate forage mixture, in the second experimental period the Br was supplemented with 100 g lecithin/day/animal. At the end of each experimental period were taken blood samples to establish some biochemical parameters from sanguine serum. The supplementation of base ration with 100 g lecithin/day/animal at lactating sheep and goats did not produced significant changes to values of total proteins (TS), albumin, creatinine, urea and total bilirubins (TB) from sanguine serum. Contrary to expectation the cholesterol and triglycerides were higher than normal both in sheep (from 82 mg/dl to 83 mg/dl for cholesterol and from 23 mg/dl to 45 mg/dl for triglycerides) but specially in goats (from 59 mg/dl to 68 mg/dl for cholesterol and from 24 mg/dl to 55 mg/dl for triglycerides). Were registered significant increment of activity of alkaline phosphatase and in γ – GT and a decrease of plasmatic activity of pancreatic α-amylase both in sheep and goats

Effect of Various Local Anthropogenic Impacts on the Diversity of Coral Mucus-Associated Bacterial Communities

The global continued decline in coral reefs is intensifying the need to understand the response of corals to local environmental stressors. Coral-associated bacterial communities have been suggested to have a swift response to environmental pollutants. This study aims to determine the variation in the bacterial communities associated with the mucus of two coral species, Pocillopora damicornis (Linnaeus, 1758) and Stylophora pistillata (Esper, 1792), and the coral-surrounding seawater from three areas exposed to contamination at the Jordanian coast of the Gulf of Aqaba (Red Sea), and also explores the antibacterial activity of these bacteria. Corals were collected from three contaminated zones along the coast, and the bacteria were quantified and identified by conventional morphological and biochemical tests, as well as 16S rRNA gene sequencing. The average number of bacteria significantly varied among the coral mucus from the sampling zones and between the coral mucus and the surrounding seawater. The P. damicornis mucus-associated bacterial community was dominated by members of the classes Gammaproteobacteria, Cytophagia, and Actinomycetia, while the mucus of S. pistillata represented higher bacterial diversity, with the dominance of the bacterial classes Gammaproteobacteria, Actinomycetia, Alphaproteobacteria, and Bacilli. The effects of local anthropogenic impacts on coral mucus bacterial communities were represented in the increased abundance of bacterial species related to coral diseases. Furthermore, the results demonstrated the existence of bacterial isolates with antibacterial activity that possibly acted as a first line of defense to protect and maintain the coral host against pathogens. Indeed, the dynamics of coral-associated microbial communities highlight the importance of holistic studies that focus on microbial interactions across the coral reef ecosystem

Identification problems for degenerate parabolic equations

summary:This paper deals with multivalued identification problems for parabolic equations. The problem consists of recovering a source term from the knowledge of an additional observation of the solution by exploiting some accessible measurements. Semigroup approach and perturbation theory for linear operators are used to treat the solvability in the strong sense of the problem. As an important application we derive the corresponding existence, uniqueness, and continuous dependence results for different degenerate identification problems. Applications to identification problems for the Stokes system, Poisson-heat equation, and Maxwell system are given to illustrate the theory