Inhibitory effect of antagonistic bio-agents and chitosan on the growth of tomato root rot pathogens In vitro

Abstract Fungal and bacterial bio-agents and the by-product chitosan as fungicides alternatives were evaluated for their inhibitory effect against the growth of tomato root rot pathogenic fungi under laboratory conditions. The tested pathogenic fungi were Fusarium oxysporum radicisycopersici, F. oxysporum lycopersici, F. solani, Rhizoctonia solani, Sclerotium rolfsii, Macrophomina phaseolinae, Pythium sp. and Phytophthora sp., Meanwhile, isolates of the antagonistic microorganisms, i.e. T. harzianum, T. viride, Bacillus subtilis, and P. fluorescens. Mycelial growth of pathogenic fungi was significantly reduced by the inhibitor action produced by all antagonistic agents tested. The antagonistic fungi had a greater effect on the retardation of growth (75.5--100%) compared with the bacterial agents (57.7-83.3%). The inhibitor effect of the two tested chitosan (High and Low molecular weight) was increased as chitosan concentration is increased in growth medium to reach its maximum at the highest concentration (5 g/L). Complete inhibition of tested fungal growth was observed at the concentration of 4 g/L of LMW chitosan, while the highest fungal growth reduction was recorded in PDA-amended with HMW at the same concentration. On the light of the present study, it could be suggested that the use of chitosan as natural safe materialsalone or in combination with bio agents is considered one of low cost and effective applicable methods for controlling such soil-borne plant pathogens causing plant diseases

Management of dry root rot disease of mandarin (Citrus reticulate Blanco) through biocomposted agricultural wastes

The effects of soil drenching with biocomposted agricultural wastes (BCAW) , Trichoderma harzianum (spore suspension 5x10 6 cfu/ml ) and Topsin-M 70% were evaluated for controlling dry root rot caused by Fusarium solani of mandarin (Citrus reticulate Blanco) under green house and field conditions. Manipulation of soil with biocompost (composted of sugarcane bagasse, rice straw and soybean straw inoculated with spore suspension 5x10 6 cfu/ml of T. harzianum isolate NB10) , T. harzianum (spore suspension 5x10 6 cfu / ml ) and Topsin M 70% successfully controlled F. solani the main pathogen of dry root rot disease on mandarin. Complete reduction of the F. solani linear growth was recorded at 100 ppm of Topsin M and T. harzianum . In greenhouse, the highest reduction in Fusarium dry root rot disease on mandarin seedlings was obtained with biocompost (BCAW) at 10% (w/w) and Topsin-M (1 g/L) . Moreover, such treatments caused highest reduction in population density of Fusarium solani in rhizosphere soil of treated seedlings , but Trichoderma population were highly increased. Under Field condition which were amended soil around stems of diseased mandarin trees by biocompost (BCAW) and Topsin-M (1 g/L) treatments as twice applications per season resulted in recovering great number of diseased trees and decreased the disease severity on others. Population density of Fusarium spp. were highly decreased, where population density of Trichoderma spp were increased in rhizosphere soil of treated trees by biocompost (BCAW) . The highest increased in fruit yield was recorded on mandarin trees treated with bio-compost and Topsin M treatments as twice soil applications. It could be suggested that using soil amendments by biocompost (composed agricultural wastes colonized by T. harzianum ) alone or in combined with a reduced rates of Topsin M 70 % (fungicide) can be successfully used to replace traditional fungicides and avoid environmental pollution

A mild ovarian stimulation strategy in women with poor ovarian reserve undergoing IVF: a multicenter randomized non-inferiority trial

In subfertile women with poor ovarian reserve undergoing IVF does a mild ovarian stimulation strategy lead to comparable ongoing pregnancy rates in comparison to a conventional ovarian stimulation strategy? A mild ovarian stimulation strategy in women with poor ovarian reserve undergoing IVF leads to similar ongoing pregnancy rates as a conventional ovarian stimulation strategy. Women diagnosed with poor ovarian reserve are treated with a conventional ovarian stimulation strategy consisting of high-dose gonadotropins and pituitary downregulation with a long mid-luteal start GnRH-agonist protocol. Previous studies comparing a conventional strategy with a mild ovarian stimulation strategy consisting of low-dose gonadotropins and pituitary downregulation with a GnRH-antagonist have been under powered and their effectiveness is inconclusive. This open label multicenter randomized trial was designed to compare one cycle of a mild ovarian stimulation strategy consisting of low-dose gonadotropins (150 IU FSH) and pituitary downregulation with a GnRH-antagonist to one cycle of a conventional ovarian stimulation strategy consisting of high-dose gonadotropins (450 IU HMG) and pituitary downregulation with a long mid-luteal GnRH-agonist in women of advanced maternal age and/or women with poor ovarian reserve undergoing IVF between May 2011 and April 2014. Couples seeking infertility treatment were eligible if they fulfilled the following inclusion criteria: female age ≥35 years, a raised basal FSH level >10 IU/ml irrespective of age, a low antral follicular count of ≤5 follicles or poor ovarian response or cycle cancellation during a previous IVF cycle irrespective of age. The primary outcome was ongoing pregnancy rate per woman randomized. Analyses were on an intention-to-treat basis. We randomly assigned 195 women to the mild ovarian stimulation strategy and 199 women to the conventional ovarian stimulation strategy. Ongoing pregnancy rate was 12.8% (25/195) for mild ovarian stimulation versus 13.6% (27/199) for conventional ovarian stimulation leading to a risk ratio of 0.95 (95% CI: 0.57-1.57), representing an absolute difference of -0.7% (95% CI: -7.4 to 5.9). This 95% CI does not extend below the predefined threshold of 10% for inferiority. The duration of ovarian stimulation was significantly lower in the mild ovarian stimulation strategy than in the conventional ovarian stimulation strategy (mean difference -1.2 days, 95% CI: -1.88 to -0.62). Also, a significantly lower amount of gonadotropins was used in the mild simulation strategy, with a mean difference of 3135 IU (95% CI: -3331 to -2940). A limitation of our study was the lack of data concerning the cryopreservation of surplus embryos, so we are not informed on cumulative pregnancy rates. Another limitation is that we were not able to follow up on the ongoing pregnancies in all centers, so we are not informed on live birth rates. The results are directly applicable in daily clinical practice and may lead to considerable cost savings as high dosages of gonadotropins are not necessary in women with poor ovarian reserve undergoing IVF. A health economic analysis of our data planned to test the hypothesis that mild ovarian stimulation strategy is more cost-effective than the conventional ovarian stimulation strategy is underway. This study was supported by NUFFIC scholarship (the Netherlands) and STDF short-term fellowship (Egypt). NTR2788 (Trialregister.nl). 01 March 2011. May 201

Natural compounds extracted from Moringa oleifera and their agricultural applications

Natural bio-active compounds synthesized by plants as secondary metabolites are well known and established. Today, their application in various fields such as medicine in the form of drugs and biopesticides in agriculture is well documented. In recent times, the delivery of such compounds is achieved through nanodelivery technology, which is gaining acceptability in both field of drugs and agrochemical industries. The bio-active compounds with chemical diversity are obtained from nature either as homogenous plant crude extracts or as purified compounds. Crude plant extracts exist as a combination of different bio-active compounds with various polarities, and their partition remains a challenge in the process of characterization and identification. Extraction of these compounds from plant species is achieved by different solvents and extraction methods. Analytical methods like HPLC have commonly been utilized with GC-MS and LC-MS/MS chromatography methods to identify the compounds. Crude extracts from different morphological parts of plant species including Moringa oleifera are increasingly becoming important in the context of agricultural pest management and human medicine. M. oleifera is a medicinal plant that synthesizes such metabolites which include phenolic acids, carotenoids, quinones, antraquinones, flavonoids, flavonols, flavones, tannins, alkaloids, coumarins, terpenoids, amines, cyanogenic glycosides, triterpenoids, non-protein amino acids, glucosinolates, polyacetylenes, polyketides, phenylpropanes, steroids and saponins. They exert biological activities and can potentially be used to retard microbial activities. Other uses of M. oleifera are medicinal uses and other purposes such as water purification, fertilizer, biogas and biopesticides. The aim of this chapter is to highlight the uses and profiling of bio-active compounds of M. oleifera, their mode of action and prospects in commercial biopesticides for agricultural applications