Seasonal variation and nutrient jointly drive the community structure of macrophytes in lakes with different trophic states

IntroductionMacrophytes are essential for maintaining the health of shallow lake ecosystems, however, the driving and responsive relationship between ecological factors (such as seasonal changes and nutrition, etc.) and plant communities is not yet clear.MethodsIn this study, we conducted seasonal surveys of macrophyte community composition in lakes with different nutrient states, aiming to understand the incidence relation between macrophyte community diversity, seasonal changes and environmental factors.ResultsAccording to the classification criteria of comprehensive nutritional index, there were significant differences in the trophic status of the three lakes. Among them, the Xihu Lake has reached mild eutrophication with a TLI value of 56.33, both Cibi Lake and Haixihai Lake are mesotrophic with TLI value of 36.03 and 33.48, respectively. The results of diversity analysis showed a significant negative correlation between α-diversity (include Species richness, Shannon-Wiener index, Simpson index and Pielou index) and lake nutrient status. Among them, Xihu Lake showed the lowest α-diversity in all seasons, Haixihai Lake exhibited the middle α-diversity, Cibi Lake indicated the highest α-diversity. Non-metric multidimensional ordination showed that there were obvious spatial structures differences among the macrophyte communities in the three lakes. Macrophyte community composition in the three lakes was more similar in summer and autumn, but there was a wider gap in spring and winter. The redundancy analysis indicated distinct differences between diversity index and ecological factors, the eigenvalues of Axis 1 and Axis 2 being, respectively, 36.13% and 8.15%. Environmental factors could explain 44.8% of the total variation in macrophyte communities structure. Among these, nitrogen, phosphorus, water transparency and water temperature contributed 50.2%, 3.5%, 3.8% and 27.5%, respectively.ConclusionsIn summary, the community structure of macrophytes in plateau shallow lakes is co-regulated by seasons and nutrients

Active removal of waste dye pollutants using Ta[sub]3N[sub]5/W[sub]18O[sub]49 nanocomposite fibres

A scalable solvothermal technique is reported for the synthesis of a photocatalytic composite material consisting of orthorhombic Ta3N5 nanoparticles and WOx≤3 nanowires. Through X-ray diffraction and X-ray photoelectron spectroscopy, the as-grown tungsten(VI) sub-oxide was identified as monoclinic W18O49. The composite material catalysed the degradation of Rhodamine B at over double the rate of the Ta3N5 nanoparticles alone under illumination by white light, and continued to exhibit superior catalytic properties following recycling of the catalysts. Moreover, strong molecular adsorption of the dye to the W18O49 component of the composite resulted in near-complete decolourisation of the solution prior to light exposure. The radical species involved within the photocatalytic mechanisms were also explored through use of scavenger reagents. Our research demonstrates the exciting potential of this novel photocatalyst for the degradation of organic contaminants, and to the authors’ knowledge the material has not been investigated previously. In addition, the simplicity of the synthesis process indicates that the material is a viable candidate for the scale-up and removal of dye pollutants on a wider scale

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Antioxidant and anti-stress properties of postbiotics produced by Lysinibacillus macroides G117

In this study, Lysinibacillus macroides G117 was isolated from vinegar residue, and the probiotic activity of its postbiotics was determined in Artemia salina and Scophthalmus maximus. First, the functional genome of L. macroides G117 was analysed. The total length of the genome was 4,728,501 bp, composed of one ring chromosome and two ring plasmids. Two gene clusters, β-lactone and type III polyketide synthases (T3PKS), well-known for anti-toxic, anti-inflammatory, antioxidant, anticancer activities, were predicted through the antiSMASH database. In addition, probiotic genes for antioxidants, stress resistance, and anaerobic respiration were identified using the KEGG database. These results suggest that L. macroides G117 could be used as a probiotic in aquaculture. To further assess the probiotic properties of L. macroides G117, postbiotics were cultured and collected. Based on the survival rate of pesticide-stimulated A. salina, the optimum culture condition of L. macroides G117 was analysed. The optimal culture conditions were 1 % sucrose, 1.5 % yeast extract, 0.1 % MgSO4·7H2O, 30 °C, pH 7.8, bottled fluid volume 100 mL, shaking speed 180 rpm, inoculation quantity 0.5 %, and fermentation for 48 h, with a 15 % increase in survival rate of A. salina with the addition of optimised postbiotics. Untargeted metabolomic analysis revealed significant differences between the non-optimised and optimised postbiotics, mainly in amino acid and carbohydrate metabolites. Notably, postbiotics significantly increased the antioxidant enzymes in A. salina (catalase (CAT) and total superoxide dismutase (T-SOD)) and S. maximus (T-SOD) and decreased malondialdehyde (MDA) content. In addition, the activities of anaerobic respiratory-related enzymes (lactate dehydrogenase (LDH) and pyruvate kinase (PK)) were significantly increased, whereas those of aerobic respiratory-related enzymes (malate dehydrogenase (MDH)) were significantly decreased in S. maximus. These results suggest that L. macroides G117 postbiotics could improve the antioxidant and anti-stress abilities of the two types of organisms

Soil Moisture Content Dominates the Photosynthesis of C₃ and C₄ Plants in a Desert Steppe after Long-Term Warming and Increasing Precipitation

Plant photosynthesis has a non-negligible influence on forage quality and ecosystem carbon sequestration. However, the influence of long-term warming, increasing precipitation, and their interactions on the photosynthesis of dominant species in desert steppe remains unclear, and the main factors regulating plant photosynthesis in desert steppes have remained unrevealed. Therefore, we measured the photosynthetic parameters and specific leaf area of the dominant species and calculated the water and nitrogen content of leaves and soil in a desert steppe after long-term warming and increasing precipitation (air temperature, W0, air temperature increases of 2 °C and 4 °C, W1 and W2; natural precipitation, P0, natural precipitation increases of 25% and 50%, P1 and P2). Results showed that warming and increasing precipitation significantly enhanced photosynthesis in C3 and C4 species (p 3 and C4 species in W2P2 increased by 159.46% and 178.88%, respectively. Redundancy analysis showed that soil water content significantly explained the photosynthesis of C3 and C4 plants (the degree of explanation was 48% and 67.7%), followed by soil-available nitrogen content (the degree of explanation was 19.6% and 5.3%). Therefore, our study found that climate change enhanced photosynthesis in C3 and C4 plants, and soil water content plays a critical role in regulating photosynthesis in desert steppes

Experimental climate change in desert steppe reveals the importance of C4 plants for ecosystem carbon exchange

Global climate change has greatly altered plant community composition and affected ecosystem carbon exchange of grasslands. However, the influences of long-term increasing temperature and precipitation on the composition of plant community and the ecosystem carbon exchange in degraded desert steppe remain unclear. After seven years of simulated climate warming (ambient temperature, W0, 2 ℃ and 4 ℃ increase in temperature, W1 and W2) and increasing precipitation (plant growing season precipitation, P0, 25% and 50% increase in precipitation, P1 and P2), we recorded the composition of plant community, the moisture and temperature of soil and calculated net ecosystem CO2 exchange (NEE). Results showed that 1) long-term warming and increasing precipitation improved the cover and height of C4 plants in the plant community, while decreasing the cover and density of C3 plants. 2) Climate warming and increasing precipitation significantly increased NEE. Compared with W0P0, the mean NEE in the plant growing season increased by 115% in W2P2. 3) Redundancy analysis showed that soil moisture content and the height and density of C4 plants significantly explained ecosystem carbon exchange (P  0.01). Therefore, our research revealed that warming and increasing precipitation positively affected ecosystem carbon exchange in degraded desert steppe through changes in plant community composition, and C4 plants will play a vital role in ecosystem carbon exchange in desert steppe under climate change

Influence of Loading Rate and Temperature on the Energy Absorption of 3D-Printed Polymeric Origami Tubes under Quasi-Static Loading

Owing to deformation in the form of the diamond mode with high-energy absorption capacity, origami thin-walled tubes have attracted considerable attention in recent years. Stamping and welding are mainly employed to produce different types of origami thin-walled tubes. The processing defects and geometric asymmetry may be caused by the manufacturing process, which changes the collapsed mode and decreases the energy-absorbing capacity. In this study, fused filament fabrication (FFF) 3D printing is used to fabricate the origami-ending tube (OET) by integrated formation. Experiments and numerical simulations were conducted to study the influence of loading rate and temperature on the energy absorption of polymeric origami tubes under quasi-static loading. The experiments showed that different constitutive models are needed to capture the complex true stress–strain behavior of 3D printing polylactic acid (PLA) material at different temperatures. The damage model is established and then applied to the numerical simulations, which could predict the collapsed mode and the damage behavior of the OET tubes under different loading rates at 30 °C, 40 °C, and 50 °C. Based on the experiments and the validated numerical model, the influence of loading rate and temperature on the crashworthiness performance of the OET tubes is analyzed

Effects of Bacillus velezensis Supplementation on the Growth Performance, Immune Responses, and Intestine Microbiota of Litopenaeus vannamei

In the present study, Bacillus velezensis (BV007, CGMCC No. 20039) was isolated from the gut of Litopenaeus vannamei, and the effects of BV007 on the growth performance, immune responses, and intestine microbiota of the shrimp were investigated. A total of 1,200 healthy shrimp (3.0 +/- 0.3 cm, 0.32 +/- 0.8 g) were randomly divided into four groups, and fed diets supplemented with different levels of BV007 (C: 0; BV1: 1 x 10(5) CFU/g; BV2: 1 x 10(7) CFU/g; and BV3: 1 x 10(9) CFU/g) for 8 weeks. The results showed a significantly increased final body length (FBL), length gain rate (LGR), final body weight (FBW), weight gain rate (WGR), plumpness index (PI), and specific growth rate (SGR) in shrimp fed with BV007 for 42 days compared with shrimp fed with control diet. The activity of alpha-amylase in hepatopancreas was also significantly increased in the BV007-administered groups. After 42 days of growth trial, the challenge test with Vibrio parahaemolyticus was conducted for 2 weeks. The enhanced immune responses were exhibited by shrimp fed with BV007 after V. parahaemolyticus challenge, particularly in respiratory bursts and superoxide dismutase, catalase, and alkaline phosphatase activities. Moreover, the administration of BV007 could considerably increase the abundance of potential probiotics (Bacillus) and reduced the abundances of potential pathogenic bacteria (Vibrio) in shrimp intestines. In conclusion, the dietary supplementation with B. velezensis BV007 could promote the growth performance, enhance the immune responses, and modulate the intestine microbiota of shrimp, and 10(7) CFU/g feed was recommended to be used as a feed additive to enhance the growth and health status of shrimp.</p

Antibacterial activities and mechanisms of action of a defensin from manila clam Ruditapes philippinarum

Defensins represent an evolutionary ancient family of antimicrobial peptides, which played an undeniably important role in host defense. In the present study, a defensin isoform was identified and characterized from manila clam Ruditapes philippinarum (designed as Rpdef1 alpha). Multiple alignments and phylogenetic analysis suggested that Rpdef1 alpha belonged to the defensin family. Quantitative RT-PCR and immunohistochemical analysis revealed that Rpdef1 alpha transcripts and the encoding peptide were dominantly expressed in the tissues of gills and mantle. After Vibrio anguillarum challenge, the Rpdef1 alpha transcripts were significantly up-regulated in gills of clams. In addition, rRpdef1 alpha not only showed broad-spectrum antimicrobial activities towards Vibrio species, but also inhibited the formation of bacterial biofilms. Knockdown of Rpdef1 alpha transcripts caused significant increase in the cumulative mortality of manila clams post V. anguillarum challenge. Membrane integrity, scanning electron microscopy analysis and electrochemical assay indicated that rRpdef1 alpha was capable of causing bacterial membrane permeabilization and then resulted in cell death. Moreover, phagocytosis and chemotactic ability of hemocytes could be significantly enhanced after incubation with rRpdef1 alpha. Overall, these results suggested that Rpdef1 alpha could act as both antibacterial agent and opsonin to defend against the invading microorganisms in manila clam R. philippinarum

Effects of the potential probiotic Bacillus subtilis D1-2 on growth, digestion, immunity and intestinal flora in juvenile sea cucumber, Apostichopus japonicus

In the present study, a potential probiotic Bacillus subtilis D1-2 with antibacterial activity was isolated from the gut of Apostichopus japonicus. The purpose of this experiment was to assess the effect of B. subtilis D1-2 at different concentrations (C: 0 CFU/g, BL: 10(5) CFU/g, BM: 10(7) CFU/g and BH: 10(9) CFU/g) on the growth performance, digestive enzyme activity, immune ability and intestinal flora of A. japonicus. After the 56-day feeding trial, the final body weight and weight gain rate of juvenile sea cucumber A. japonicus fed B. subtilis D1-2 were significantly increased, especially in the BM group. Additionally, the lipase activity of the intestine was significantly increased in the BM and BH groups. Enhanced immunity was also found in sea cucumbers supplemented with B. subtilis D1-2. Alpha diversity indices showed that the B. subtilis D1-2-supplemented groups had higher intestinal microbial richness and diversity than the control group. The beta diversity analysis indicated that the bacterial communities in the B. subtilis D1-2-supplemented groups were quite similar but different from the bacterial communities in the control group. Dietary supplementation with B. subtilis D1-2 increased the relative abundance of some potential probiotic-related genera, including Lactobacillus, Clostridium, Lactococcus, Bifidobacterium and Streptococcus. In conclusion, dietary addition of B. subtilis D1-2 could effectively promote the growth of A. japonicus, improve its digestion and immunity capacity to a certain extent, and actively regulate the intestinal microflora of A. japonicus