Isolation and identification of antagonistic Bacillus amyloliquefaciens HSE-12 and its effects on peanut growth and rhizosphere microbial community

The HSE-12 strain isolated from peanut rhizosphere soil was identified as Bacillus amyloliquefaciens by observation of phenotypic characteristics, physiological and biochemical tests, 16S rDNA and gyrB gene sequencing. In vitro experiments showed that the strain possessed biocontrol activity against a variety of pathogens including Sclerotium rolfsii. The strain has the ability to produce hydrolytic enzymes, as well as volatile organic compounds with antagonistic and probiotic effects such as ethyleneglycol and 2,3-butanediol. In addition, HSE-12 showed potassium solubilizing (10.54 ± 0.19 mg/L), phosphorus solubilization (168.34 ± 8.06 mg/L) and nitrogen fixation (17.35 ± 2.34 mg/g) abilities, and was able to secrete siderophores [(Ar-A)/Ar × 100%: 56%] which promoted plant growth. After inoculating peanut with HSE-12, the available phosphorus content in rhizosphere soil increased by 27%, urease activity increased by 43%, catalase activity increased by 70% and sucrase activity increased by 50% (p < 0.05). The dry weight, fresh weight and the height of the first pair of lateral branches of peanuts increased by 24.7, 41.9, and 36.4%, respectively, compared with uninoculated peanuts. In addition, compared with the blank control, it increased the diversity and richness of peanut rhizosphere bacteria and changed the community structure of bacteria and fungi. The relative abundance of beneficial microorganisms such as Sphingomonas, Arthrobacter, RB41, and Micromonospora in rhizosphere soil was increased, while the relative abundance of pathogenic microorganisms such as Aspergillus, Neocosmospora, and Rhizoctonia was decreased

Cardiovascular mortality by cancer risk stratification in patients with localized prostate cancer: a SEER-based study

PurposeThe risk of cardiovascular disease (CVD) mortality in patients with localized prostate cancer (PCa) by risk stratification remains unclear. The aim of this study was to determine the risk of CVD death in patients with localized PCa by risk stratification.Patients and methodsPopulation-based study of 340,806 cases in the Surveillance, Epidemiology, and End Results (SEER) database diagnosed with localized PCa between 2004 and 2016. The proportion of deaths identifies the primary cause of death, the competing risk model identifies the interaction between CVD and PCa, and the standardized mortality rate (SMR) quantifies the risk of CVD death in patients with PCa.ResultsCVD-related death was the leading cause of death in patients with localized PCa, and cumulative CVD-related death also surpassed PCa almost as soon as PCa was diagnosed in the low- and intermediate-risk groups. However, in the high-risk group, CVD surpassed PCa approximately 90 months later. Patients with localized PCa have a higher risk of CVD-related death compared to the general population and the risk increases steadily with survival (SMR = 4.8, 95% CI 4.6–5.1 to SMR = 13.6, 95% CI 12.8–14.5).ConclusionsCVD-related death is a major competing risk in patients with localized PCa, and cumulative CVD mortality increases steadily with survival time and exceeds PCa in all three stratifications (low, intermediate, and high risk). Patients with localized PCa have a higher CVD-related death than the general population. Management of patients with localized PCa requires attention to both the primary cancer and CVD

Preliminary Numerical Analysis of the Efficiency of a Central Lake Reservoir in Enhancing the Flood and Drought Resistance of Dongting Lake

During the past few decades, the ecosystems of lakes have been reshaped greatly by global climate change and expanding human activities. As the second largest freshwater lake in China, Dongting Lake is the most important regulating lake in the Yangtze River Basin because it has extensive flood storage capacity. The dynamic characteristics of its circulation and sediment transport are significantly affected by the scheduling and interception of control reservoirs at the upper reaches of the Yangtze River. In this paper, a central lake reservoir is proposed to improve the flood and drought resistance of Dongting Lake. The efficiency of the central lake reservoir is investigated numerically by developing a two-dimensional shallow water model. We demonstrate that current velocity and water elevation during flood and drought events can be influenced significantly by the construction of the central lake reservoir. The flood storage capacity of the central lake reservoir can reduce the peak flood elevation significantly in West Dongting Lake, which would enhance its flood resistance. The water replenishment of the central lake reservoir in the dry season can also efficiently increase the lake water elevation to enhance the drought resistance in the area surrounding the lake. Our findings have important implications for policy makers and their management of Dongting Lake

The Positive Effects of Growth Mindset on Students’ Intention toward Self-Regulated Learning during the COVID-19 Pandemic: A PLS-SEM Approach

The COVID-19 pandemic has brought unprecedented challenges to students’ learning processes in higher education. This study aimed to investigate the effects of a growth mindset on university students’ intention toward self-regulated learning during the COVID-19 pandemic. The theoretical model was proposed based on the Theory of Planned Behavior, along with two additional dimensions: growth mindset and perceived teacher support. The developed model was validated by adopting a partial least squares structural equation modeling (PLS-SEM) approach based on the data collected from 486 students in universities that have been significantly impacted by the COVID-19 pandemic in China. The results show that students’ growth mindset is positively associated with their intention toward self-regulated learning directly, and indirectly through the main constructs of the Theory of Planned Behavior: perceived behavioral control and behavior attitude. Additionally, the mediating and moderating roles of students’ growth mindset are manifest in the relationship between students’ perception of teacher support and their intention toward self-regulated learning. These findings offer implications for teachers, researchers, and higher education administrators in developing students’ growth mindset by considering the relevant factors explored in this research, thereby enhancing students’ self-regulated learning in challenging settings such as the COVID-19 pandemic

Combined application of microbial inoculant and kelp-soaking wastewater promotes wheat seedlings growth and improves structural diversity of rhizosphere microbial community

Abstract Industrial processing of kelp generates large amounts of kelp-soaking wastewater (KSW), which contains a large amount of nutrient-containing substances. The plant growth-promoting effect might be further improved by combined application of growth-promoting bacteria and the nutrient-containing KSW. Here, a greenhouse experiment was conducted to determine the effect of the mixture of KSW and Bacillus methylotrophicus M4-1 (MS) vs. KSW alone (SE) on wheat seedlings, soil properties and the microbial community structure in wheat rhizosphere soil. The available potassium, available nitrogen, organic matter content and urease activity of MS soil as well as the available potassium of the SE soil were significantly different (p < 0.05) from those of the CK with water only added, increased by 39.51%, 36.25%, 41.61%, 80.56% and 32.99%, respectively. The dry and fresh weight of wheat seedlings from MS plants increased by 166.17% and 50.62%, respectively, while plant height increased by 16.99%, compared with CK. Moreover, the abundance and diversity of fungi in the wheat rhizosphere soil were significantly increased (p < 0.05), the relative abundance of Ascomycetes and Fusarium spp. decreased, while the relative abundance of Bacillus and Mortierella increased. Collectively, the combination of KSW and the plant growth-promoting strain M4-1 can promote wheat seedlings growth and improve the microecology of rhizosphere microorganisms, thereby solving the problems of resource waste and environmental pollution, ultimately turning waste into economic gain

Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Wheat

Biocontrol by inoculation with beneficial microbes is a proven strategy for reducing the negative effect of soil-borne pathogens. We evaluated the effects of microbial inoculants BIO-1 and BIO-2 in reducing soil-borne wheat diseases and in influencing wheat rhizosphere microbial community composition in a plot test. The experimental design consisted of three treatments: (1) Fusarium graminearum F0609 (CK), (2) F. graminearum + BIO-1 (T1), and (3) F. graminearum F0609 + BIO-2 (T2). The results of the wheat disease investigation showed that the relative efficacies of BIO-1 and BIO-2 were up to 82.5% and 83.9%, respectively. Illumina MiSeq sequencing revealed that bacterial abundance and diversity were significantly higher (P<0.05) in the treatment groups (T1 and T2) than in the control, with significantly decreased fungal diversity in the T2 group. Principal coordinates and hierarchical clustering analyses revealed that the bacterial and fungal communities were distinctly separated between the treatment and control groups. Bacterial community composition analysis demonstrated that beneficial microbes, such as Sphingomonas, Bacillus, Nocardioides, Rhizobium, Streptomyces, Pseudomonas, and Microbacterium, were more abundant in the treatment groups than in the control group. Fungal community composition analysis revealed that the relative abundance of the phytopathogenic fungi Fusarium and Gibberella decreased and that the well-known beneficial fungi Chaetomium, Penicillium, and Humicola were more abundant in the treatment groups than in the control group. Overall, these results confirm that beneficial microbes accumulate more easily in the wheat rhizosphere following application of BIO-1 and BIO-2 and that the relative abundance of phytopathogenic fungi decreased compared with that in the control group

Cloning, Synthesis and Functional Characterization of a Novel α-Conotoxin Lt1.3

α-Conotoxins (α-CTxs) are small peptides composed of 11 to 20 amino acid residues with two disulfide bridges. Most of them potently and selectively target nicotinic acetylcholine receptor (nAChR) subtypes, and a few were found to inhibit the GABAB receptor (GABABR)-coupled N-type calcium channels (Cav2.2). However, in all of α-CTxs targeting both receptors, the disulfide connectivity arrangement “C1-C3, C2-C4” is present. In this work, a novel α4/7-CTx named Lt1.3 (GCCSHPACSGNNPYFC-NH2) was cloned from the venom ducts of Conus litteratus (C. litteratus) in the South China Sea. Lt1.3 was then chemically synthesized and two isomers with disulfide bridges “C1-C3, C2-C4” and “C1-C4, C2-C3” were found and functionally characterized. Electrophysiological experiments showed that Lt1.3 containing the common disulfide bridges “C1-C3, C2-C4” potently and selectively inhibited α3β2 nAChRs and not GABABR-coupled Cav2.2. Surprisingly, but the isomer with the disulfide bridges “C1-C4, C2-C3” showed exactly the opposite inhibitory activity, inhibiting only GABABR-coupled Cav2.2 and not α3β2 nAChRs. These findings expand the knowledge of the targets and selectivity of α-CTxs and provide a new structural motif to inhibit the GABABR-coupled Cav2.2

Image_1_Isolation and identification of antagonistic Bacillus amyloliquefaciens HSE-12 and its effects on peanut growth and rhizosphere microbial community.JPEG

The HSE-12 strain isolated from peanut rhizosphere soil was identified as Bacillus amyloliquefaciens by observation of phenotypic characteristics, physiological and biochemical tests, 16S rDNA and gyrB gene sequencing. In vitro experiments showed that the strain possessed biocontrol activity against a variety of pathogens including Sclerotium rolfsii. The strain has the ability to produce hydrolytic enzymes, as well as volatile organic compounds with antagonistic and probiotic effects such as ethyleneglycol and 2,3-butanediol. In addition, HSE-12 showed potassium solubilizing (10.54 ± 0.19 mg/L), phosphorus solubilization (168.34 ± 8.06 mg/L) and nitrogen fixation (17.35 ± 2.34 mg/g) abilities, and was able to secrete siderophores [(Ar-A)/Ar × 100%: 56%] which promoted plant growth. After inoculating peanut with HSE-12, the available phosphorus content in rhizosphere soil increased by 27%, urease activity increased by 43%, catalase activity increased by 70% and sucrase activity increased by 50% (p < 0.05). The dry weight, fresh weight and the height of the first pair of lateral branches of peanuts increased by 24.7, 41.9, and 36.4%, respectively, compared with uninoculated peanuts. In addition, compared with the blank control, it increased the diversity and richness of peanut rhizosphere bacteria and changed the community structure of bacteria and fungi. The relative abundance of beneficial microorganisms such as Sphingomonas, Arthrobacter, RB41, and Micromonospora in rhizosphere soil was increased, while the relative abundance of pathogenic microorganisms such as Aspergillus, Neocosmospora, and Rhizoctonia was decreased.</p