RESUMO
Strawberry root rot caused by Fusarium solani is one of the main diseases of strawberries and significantly impacts the yield and quality of strawberry fruit. Biological control is becoming an alternative method for the control of plant diseases to replace or decrease the application of traditional chemical fungicides. To obtain antagonistic bacteria with a high biocontrol effect on strawberry root rot, over 72 rhizosphere bacteria were isolated from the strawberry rhizosphere soil and screened for their antifungal activity against F. solani by dual culture assay. Among them, strains CMS5 and CMR12 showed the strongest inhibitory activity against F. solani (inhibition rate 57.78% and 65.93%, respectively) and exhibited broad-spectrum antifungal activity. According to the phylogenetic tree based on 16S rDNA and gyrB genes, CMS5 and CMR12 were identified as Bacillus amyloliquefaciens. Lipopeptide genes involved in surfactin, iturin, and fengycin biosynthesis were detected in the DNA genomes of CMS5 and CMR12 by PCR amplification. The genes related to the three major lipopeptide metabolites existed in the DNA genome of strains CMS5 and CMR12, and the lipopeptides could inhibit the mycelial growth of F. solani and resulted in distorted hyphae. The inhibitory rates of lipopeptides of CMS5 and CMR12 on the spore germination of F. solani were 61.00% and 42.67%, respectively. The plant-growth-promoting (PGP) traits in vitro screening showed that CMS5 and CMR12 have the ability to fix nitrogen and secreted indoleacetic acid (IAA). In the potting test, the control efficiency of CMS5, CMR12 and CMS5+CMR12 against strawberry root rot were 65.3%, 67.94% and 88.00%, respectively. Furthermore, CMS5 and CMR12 enhanced the resistance of strawberry to F. solani by increasing the activities of defense enzymes MDA, CAT and SOD. Moreover, CMS5 and CMR12 significantly promoted the growth of strawberry seedlings such as root length, seedling length and seedling fresh weight. This study revealed that B. amyloliquefaciens CMS5 and CMR12 have high potential to be used as biocontrol agents to control strawberry root rot.
RESUMO
Background: A better understanding of the current features of lung cancer clinical research registration is important for improving registration quality and standardizing the registration. This study aimed to assess the registration quality of lung cancer studies on ClinicalTrials.gov and analyze the influencing factors. Methods: Lung cancer clinical researches registered in the ClinicalTrials.gov database were searched on 7 July 2021. The characteristics of trials that registered up to 7 July 2021 were assessed. The quality of completed and terminated lung cancer studies from 1 July 2007 to 7 July 2020 was assessed using a modified version of the World Health Organization (WHO) Trial Registration Data Set (TRDS, V.1.3.1). Multivariate logistic regression analysis was also used to analyze the factors influencing study registration quality. An above-average registration quality score represented a high registration quality. Results: A total of 6,448 clinical studies on lung cancer were used to summarise the registration characteristics. Most interventional studies were randomized (41.88%), single group (48.07%), and open-label (82.86%) studies, while most observational studies were cohort studies (59.08%). In total, 2,171 completed and terminated studies were assessed, with an average quality score (out of 54) of 36.76±5.69. None of the assessed studies had a 100% modified TRDS reporting rate, and missing summary results were the main factor affecting the quality scores. Multivariate logistic regression analyses showed that prospective registrations [adjusted odds ratio (aOR), 2.18; 95% confidence interval (CI), 1.79-2.65], multi-center studies (aOR, 1.73; 95% CI, 1.39-2.16), government-sponsored studies (aOR, 3.09; 95% CI, 1.48-6.42), and published studies (aOR, 1.43; 95% CI, 1.15-1.78) were more likely to be high quality research. Conclusions: To improve the quality of registration, awareness of prospective registration should be further improved and government investment should be increased. At the same time, more efficient and extensive data sharing after completion of the studies should be actively promoted.
RESUMO
Taking the slope of Suiyu Railway to study, the research separately studied soil resistivity, soil electrochemistry (corrosion potential, oxidization reduction potential, electric potential gradient and pH), soil anions (total soluble salt, Cl(-), SO4(2-) and ), and soil nutrition (moisture content, organic matter, total nitrogen, alkali-hydrolysable nitrogen, available phosphorus, and available potassium) at different slope levels, and conducted corrosion grade evaluation on artificial soil according to its single index and comprehensive indexes. Compared with other factors, water has the biggest impact on the corrosion of slope protection net, followed by anion content. Total soluble salt has the moderate impact on the corrosion of slope protection net, and stray current has the moderate impact on the corrosion of mid-slope protection net. Comprehensive evaluation on the corrosive degree of soil samples indicates that the corrosion of upper slope is moderate, and the corrosion of mid-slope and lower slope is strong. Organic matter in soil is remarkably relevant to electric potential gradient. Available nitrogen, available potassium and available phosphorus are remarkably relevant to anions. The distribution of soil nutrient is indirectly relevant to slope type.
RESUMO
Artificial soil is often sprayed onto cut slopes alongside railroad tracks to promote revegetation. This study evaluated the heavy metal content and the distribution of heavy metal chemical fractions in the soil, as well as the uptake of heavy metals by plants. The soil at four sites was determined to be considerably contaminated with Cd and Pb. The concentrations of Cd and Pb increased with the length of time the railway had been in use and decreased further away from the railway tracks. Pb primarily existed in reducible form but as residual fractions, whereas Cd was predominantly in exchangeable form. A correlation analysis indicated that pH, organic matter, and total phosphorus levels were important factors affecting the distribution of the heavy metal chemical fractions. The amounts of exchangeable Pb and Cd in the soil were highly correlated with their amounts in the plants sampled, indicating that the exchangeable fraction is a better indication of heavy metal phytoavailability than the total amount of heavy metals in the soil. Bioaccumulation and translocation factors indicated that Indigofera amblyantha had moderate tolerance and bioaccumulation capability for Pb, as did Leucaena leucocephala for Cd. These two plant species can serve as ideal slope remediation plants.
