Climate change is affecting the global hydrological cycle and is causing drastic changes in the freshwater hydrological regime. Water level (WL) reduction caused by drought tends to increase the ...concentration of nutrients favoring the dominance of cyanobacteria. We hypothesized that the WL reduction favors the dominance of cyanobacteria at regular dry conditions, but at extremely dry events mixotrophic algae would thrive because of light limitation due to increased resuspension of sediments on the water column. To test our hypothesis, we compared phytoplankton traits and water quality variables between two sets of reservoirs located in two watersheds with contrasting precipitation regimes within the Brazilian semi-arid. The reservoirs were compared in a dry period and in an extremely dry period to evaluate the response of the variables to an extreme drought. Drought intensification decreased the reservoirs’ WL and water transparency and increased the total phosphorous. Cyanobacteria dominated in the dry period, and the contribution of mixotrophic algae increased in the extremely dry period. Thus, phytoplankton with mixotrophic potential was favored by the extreme drought. This result suggests that this can be one possible scenario for phytoplankton communities in reservoirs of semi-arid regions if extreme droughts become more frequent because of climate change.
Climate change is affecting the global hydrological cycle, causing drastic changes in precipitation patterns. Extreme climatic events are becoming more frequent and intense than in the past, leading ...to water-level fluctuations and affecting aquatic ecosystems. Semiarid regions are very susceptible to changing climate. We analyzed a 10 years dataset from a tropical semiarid reservoir during extreme hydrological events (heavy rains and prolonged drought), and evaluated phytoplankton functional responses to environmental conditions. We found, as hypothesized, that phytoplankton functional structure change in a temporal scale due to water–volume fluctuation induced by the rainfall pattern. Depth and inorganic material acted as environmental filters selecting phytoplankton groups. High water level seems to improve water quality and low water level worsen it. Colonial and filamentous cyanobacteria dominate the wet period; however, it may have a critical threshold during severe periods of drought, which will lead to dominance of groups well adapted to low light conditions and with mixotrophic metabolism. Phytoplankton functional approaches can simplify phytoplankton identification and reflect better the environmental conditions than the taxonomic approach. Therefore, these approaches can help to understand the shifts in aquatic ecosystems under extreme hydrological events and predict functional response of phytoplankton being an important tool to water management and conservation.
Caryocar coriaceum Wittm. fruit pulp fixed oil (CCFO) has been widely employed by communities from Brazil Northeastern in the treatment of skin inflammation, respiratory affections, wound healing and ...muscle pain. In this study, we evaluated the topical effect of CCFO against different irritant agents
in vivo, in order to verify its antiedematous effect as well to unravel its tentative mechanisms of action.
CCFO was obtained from
Caryocar coriaceum fruits using ethyl acetate as solvent. Ear edema provoked by the application of Croton oil (single and multiple applications), arachidonic acid (AA), capsaicin, phenol and histamine to Swiss mice was used to evaluate the topical anti-inflammatory effect of CCFO. Histological analysis from mice ears sensitized with Croton oil and AA single application was also performed.
Crude CCFO (20
μL/ear) demonstrated significant topical antiedematous effect against Croton oil single (inhibition of 32.0%;
P
<
0.05) and multiple (41.4% after 9 days,
P
<
0.001) applications, AA (inhibition of 49.7%;
P
<
0.01) and phenol (inhibition of 38.8%;
P
<
0.001). In contrast, CCFO did not antagonize the edema caused by topical treatment with capsaicin and histamine when compared to control group (
P
>
0.05). Histological analysis also revealed that CCFO was able to reduce the edema and the influx of inflammatory cells in mice ears sensitized with Croton oil and AA.
CCFO exhibited a similar profile of topical anti-inflammatory activity to that of drugs that classically modulate the production of arachidonic acid metabolites. The study also indicates the potential application of CCFO as an important herbal medicine to be used against skin inflammatory diseases.
We investigated the roles of a benthivorous (
Prochilodus brevis,
Steindachner 1875) and a planktivorous (
Oreochromis niloticus,
Linnaeus, 1758) fish in translocating phosphorus from the benthic to ...the pelagic habitat of a tropical eutrophic shallow lake and its impact on phytoplankton biomass and water transparency. We performed two field experiments in 20 mesocosms (6 m
3
) with a 2 × 2 factorial design. Fish presence/absence was manipulated in combination with the presence/absence of a fish cage (4 m
3
) that prevented fish accessing the sediment. Benthivorous fish increased total phosphorus and chlorophyll a concentrations and decreased water transparency, but only when they had access to the sediment. Planktivorous fish increased the concentration of chlorophyll a without changing total phosphorus concentrations, whether or not they had access to the sediment. Results suggest that only the benthivorous fish increased phytoplankton biomass by translocating phosphorus from benthic to pelagic habitats. However, the planktivorous fish increased phytoplankton biomass by removing zooplankton and recycling nutrients within the pelagic zone. We conclude that removal of either fish species can improve the water quality of eutrophic shallow lakes in tropical regions, but only the removal of benthivorous fish will reduce the internal loading of phosphorus.
8, our analysis revealed no difference between the thiamine and placebo groups in the need for RRT, even after adjusting for age, sex, creatinine, and APACHE II (Table 1). ...research is still needed ...to refine methods for accurately measuring thiamine levels and to identify which patient subpopulations might benefit most from thiamine administration. ...we can conclude that, to date, taken together, study results have not consistently demonstrated benefits with thiamine supplementation in patients with septic shock, including decreased mortality and renal protection. Availability of data and materials The datasets utilized and/or analyzed during this study can be obtained from the corresponding author upon reasonable request.
Bacteria are essential in arsenic cycling. However, few studies have addressed 16S rRNA and arsenic-related functional gene diversity in long-term arsenic-contaminated tropical sediment. Here, using ...culture-based, metagenomic and computational approaches, we describe the diversity of bacteria, genes and enzymes involved in AsIII and AsV transformation in freshwater sediment and in anaerobic AsIII- and AsV-enrichment cultures (ECs). The taxonomic profile reveals significant differences among the communities. Arcobacter, Dechloromonas, Sedimentibacter and Clostridium thermopalmarium were exclusively found in ECs, whereas Anaerobacillus was restricted to AsV-EC. Novel taxa that are both AsV-reducers and AsIII-oxidizers were identified: Dechloromonas, Acidovorax facilis, A. delafieldii, Aquabacterium, Shewanella, C. thermopalmarium and Macellibacteroides fermentans. Phylogenic discrepancies were revealed among the aioA, arsC and arrA genes and those of other species, indicating horizontal gene transfer. ArsC and AioA have sets of amino acids that can be used to assess their functional and structural integrity and familial subgroups. The positions required for AsV reduction are conserved, suggesting strong selective pressure for maintaining the functionality of ArsC. Altogether, these findings highlight the role of freshwater sediment bacteria in arsenic mobility, and the untapped diversity of dissimilatory arsenate-reducing and arsenate-resistant bacteria, which might contribute to arsenic toxicity in aquatic environments.
•Polysaccharides from mushroom Tylopilus balluii was analyzed by IR, HPLC and NMR.•The antioxidant activity of this fucogalactomannan was assessment in vitro.•This polysaccharide reduced inflammatory ...effect on paw edema and have antioxidant effect.
Fucogalactomannan (FGM) is a non-sulphated polysaccharide isolated from the Tylopilus ballouii mushroom. We investigated the chemical characteristics of this FGM using HPLC, chemical methods, and NMR studies (1H, 13C, 1H/13C-HSQC and DEPT-135 spectroscopies) without chemical fragmentation. This polysaccharide consisted primarily of mannose and galactose with variable amounts of fucose and traces of xylose and with MW of 140kDa. Infrared and NMR spectroscopies showed the possible interaction between these polysaccharides and proteins. The antioxidant activity showed for FGM a high inhibition of superoxide and hydroxyl radicals with an IC50 of 1.25 and 1.6mg/mL, respectively. The results of peroxidation tests showed that FGM had an IC50 of 1.72mg/mL. Furthermore, the anti-inflammatory assay showed that FGM reduced edema by 32.8%, 42.0%, and 56% at doses of 30, 50, and 70mg/kg, respectively. Thus, these results suggested a structure and indicated possible anti-inflammatory and antioxidant activities use of these polysaccharides.
The bacterial community and genes involved in geobiocycling of arsenic (As) from sediment impacted by long-term gold mining were characterized through culture-based analysis of As-transforming ...bacteria and metagenomic studies of the arsC, arrA, and aioA genes. Sediment was collected from the historically gold mining impacted Mina stream, located in one of the world's largest mining regions known as the "Iron Quadrangle". A total of 123 As-resistant bacteria were recovered from the enrichment cultures, which were phenotypically and genotypically characterized for As-transformation. A diverse As-resistant bacteria community was found through phylogenetic analyses of the 16S rRNA gene. Bacterial isolates were affiliated with Proteobacteria, Firmicutes, and Actinobacteria and were represented by 20 genera. Most were AsV-reducing (72%), whereas AsIII-oxidizing accounted for 20%. Bacteria harboring the arsC gene predominated (85%), followed by aioA (20%) and arrA (7%). Additionally, we identified two novel As-transforming genera, Thermomonas and Pannonibacter. Metagenomic analysis of arsC, aioA, and arrA sequences confirmed the presence of these genes, with arrA sequences being more closely related to uncultured organisms. Evolutionary analyses revealed high genetic similarity between some arsC and aioA sequences obtained from isolates and clone libraries, suggesting that those isolates may represent environmentally important bacteria acting in As speciation. In addition, our findings show that the diversity of arrA genes is wider than earlier described, once none arrA-OTUs were affiliated with known reference strains. Therefore, the molecular diversity of arrA genes is far from being fully explored deserving further attention.
Tupinambis merianae is one of the most frequently used animals in traditional medicine in Brazil as its body fat has many different therapeutic indications as a folk remedy. The present study ...evaluated the topical anti-inflammatory activity of
Tupinambis merianae fat in treating ear edema in an animal model.
Oil (OTM) was extracted from body fat located in the ventral region of
Tupinambis merianae using hexane as a solvent. Ear edema provoked by the application of croton oil (single and multiple application), arachidonic acid, phenol and capsaicin to
Swiss mice was used to evaluate the potential anti-inflammatory value of the topical use of OTM. Topical applications of these irritants were made to the right ears of animals that were pre-treated with a acetone (control), dexamethasone, or OTM.
Our results indicate that
Tupinambis merianae fat demonstrates significant topical anti-inflammatory activity that reduces inflammation related to ear edema caused by croton oil (single and multiple application), arachidonic acid, phenol. While the inflammation caused by capsaicin, OTM did not significantly reduce the edema.
This represents the first evidence of anti-inflammatory activity of
Tupinambis merianae fat in
in vivo models, confirming its usefulness in traditional medicine as a remedy for skin diseases (dermatitis). The fatty acids present in OTM most likely inhibit the response pathway of arachidonic acid and its metabolites, thus reducing the production of pro-inflammatory mediators.
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