Seed-borne endophytic Bacillus velezensis LHSB1 mediate the biocontrol of peanut stem rot caused by Sclerotium rolfsii.

AIMS: This study aimed to obtain an antagonistic endophyte against Sclerotium rolfsii from peanut seeds, evaluate the biocontrol efficacy towards peanut stem rot and explore its antifungal mechanism against S. rolfsii. METHODS AND RESULTS: Thirty-seven endophytic bacteria were isolated from peanut seeds, six of which exhibited stronger antagonistic activities against S. rolfsii (inhibition rate, IR of hyphae growth ≥70%). Strain LHSB1, the strongest antagonistic strain, was identified as Bacillus velezensis. LHSB1 showed 93·8% of radial growth inhibition of S. rolfsii hyphae and exhibited obvious antagonistic activity against another six pathogenic fungi of peanut. Pot experiments showed two different LHSB1 treatments both significantly reduced the disease incidence and severity of stem rot (P < 0·05) compared to the controls, and the biocontrol efficacy reached 62·6-70·8%, significantly higher than that of Carbendazim control (P < 0·05). Further analyses revealed LHSB1 culture filtrate significantly inhibited sclerotia formation and germination, caused the abnormalities and membrane integrity damage of S. rolfsii hyphae, which might be the possible mode of action of LHSB1 against S. rolfsii. Three antifungal lipopeptides bacillomycin A, surfactin A and fengycin A, were detected in LHSB1 culture extracts by UPLC-ESI-MS, which could be responsible for the biocontrol activity of LHSB1 against S. rolfsii. CONCLUSION: Our results suggested that the seed-borne endophytic B. velezensis LHSB1 would be a tremendous potential agent for the biocontrol of peanut stem rot caused by S. rolfsii. SIGNIFICANCE AND IMPACT OF THE STUDY: This comprehensive study provides a candidate endophytic biocontrol strain and reveals its antifungal mechanism against S. rolfsi. To the best of our knowledge, this is the first time that seed-borne endophytic B. velezensis was used as the biocontrol agent to control peanut stem rot.

Incidence of vaginal erosion with different synthetic materials for suburethral sling in the treatment of Stress Urinary Incontinence: A systematic review.

INTRODUCTION: The aim of this systematic review is to compare the vaginal erosion rates in different synthetic materials used in suburethral slings in Tension Free Vaginal Tape (TVT-O /TOT) procedures in management of female stress urinary incontinence. METHODS: PRISMA 2009 framework was adopted for study design. Scholarly literature search was done using MEDLINE, EMBASE, the Cochrane Library and Clinical Trials.gov using selected keywords. Five articles fulfilled the inclusion and exclusion criteria. Our main outcome of interest is to review the ideal properties of the suburethral sling, procedure of insertion and post-surgical complication following the sling insertion primarily vaginal erosion. Results were compared using one way-ANOVA test and independent T- test. RESULTS: Total of 1725 subjects were available for analysis in the five studies. Monofilament polypropylene constituted 92.5% of the total sample size from one study alone. Polyester (n= 16/51) causes higher incidence rate of vaginal erosion compared to monofilament polypropylene (31.4 vs., 4.7; p = 0.01). There was no difference in the vaginal erosion rate between monofilament polypropylene and multifilament polypropylene (4.7 vs, 14.1; p=0.055) as well as between multifilament polypropylene and polyester (14.1 vs, 31.4; p=0.068). Although there was a marginally lower rate of vaginal erosion in TVT-O over TVT, the difference was not significant. (5.6 vs., 6.4, p=0.468). Common presentations of vaginal erosion were vaginal discharge, perineal pain and dyspareunia. CONCLUSION: Given the limited sample size, polyester sling material appears to cause higher rates of vaginal erosion. No difference in erosion rate was seen between TVT and TVT-O.

Alterations in ATP-dependent calcium uptake by rat renal cortex microsomes following ochratoxin A administration in vivo or addition in vitro.

A disruption of calcium homeostasis, leading to a sustained increase in cytosolic calcium levels, has been associated with cytotoxicity in response to a variety of agents in different cell types. We have observed that administration of a single high dose or multiple lower doses of the carcinogenic nephrotoxin ochratoxin A (OTA) to rats resulted in an increase of the renal cortex endoplasmic reticulum ATP-dependent calcium pump activity. The increase was very rapid, being evident within 10 min of OTA administration and remained elevated for at least 6 hr thereafter. The increase in calcium pump activity was inconsistent with previous observations that OTA enhances lipid peroxidation (ethane exhalation) in vivo, a condition known to inhibit the calcium pump. However, no evidence of enhanced lipid peroxidation was observed in the renal cortex since levels of malondialdehyde and a variety of antioxidant enzymes including catalase, DT-diaphorase, superoxide dismutase, glutathione peroxidase, glutathione reductase and glutathione S-transferase were either unaltered or reduced. In in vitro studies, addition of OTA to cortex microsomes during calcium uptake inhibited the uptake process although the effect was reversible. Preincubation of microsomes with NADPH had a profound inhibitory effect on calcium uptake but inclusion of OTA was able to reverse the inhibition. Changes in the rates of microsomal calcium uptake correlated with changes in the steady-state levels of the phosphorylated Mg2+/Ca(2+)-ATPase intermediate, suggesting that in vivo/in vitro conditions were affecting the rate of enzyme phosphorylation.

Alterations in calcium homeostasis as a possible cause of ochratoxin A nephrotoxicity.

Disruption of calcium homeostasis, leading to a sustained increase in cytosolic calcium level, has been associated with cytotoxicity in response to a variety of agents in different cell types. We have observed that a single high dose or multiple lower doses of ochratoxin A administered to rats resulted in an increase in renal endoplasmic reticulum calcium pump activity. The increase was very rapid, being evident within 10 min of ochratoxin A administration and remained elevated for at least 6 h thereafter. Ochratoxin A also decreased renal mitochondrial state-3 respiration and calcium uptake. The latter may lead to an increase in cytosolic calcium level, and the increase in microsomal calcium uptake activity may be an attempt to restore calcium homeostasis. Repeated moderate doses of ochratoxin A led to an eventual decrease in microsomal calcium pump activity, and this could lead to even higher cytosolic calcium levels. Changes in the rate of microsomal calcium uptake correlated with changes in the steady-state levels of the phosphorylated Mg2+/Ca(2+)-ATPase intermediate, indicating that this enzyme is responsible for the calcium pump activity.