Crossmccabe5159

Saprolegnia spp. water moulds are opportunistic pathogens that can cause economic losses to aquaculture. The diseases caused by them are difficult to control since use of the effective drug, malachite green oxalate, is no longer permitted in several regions (including the European Union and USA). To develop an effective control strategy, Saprolegnia isolates must be maintained in the laboratory. read more Cryopreservation is a useful solution for long-term maintenance; however, at present, there is no developed protocol for the cryopreservation of Saprolegnia spp. Here, we isolated and identified three Saprolegnia species, S. parasitica, S. australis and S. ferax, and developed a deep-freezing protocol that enables the long-term archiving of these species. The survival and growth rates of isolates kept at -80 °C for 3, 6, 9 and 12 months, were tested and compared among the species examined. Although the growth rates of frozen isolates were significantly lower than those of the control (i.e. non-frozen) isolates, the overall survival rate (>90%) indicated the effectiveness of the technique developed. Thus, the protocol developed appears to be a promising method for the long-term preservation of Saprolegnia isolates and may facilitate the creation of stock collections.Silver nanoparticles (Ag NP) were synthesized using rice leaf extract and optimized synthetic conditions were found to be 0.4 % leaf extract, 0.6 mM AgNO3 and 30 min of autoclaving. Produced NP were characterized using UV-vis, DLS, zeta potential, XRD, TEM and FTIR. Ag NP formation was established from UV-vis spectra and NP showed zeta potential value of -27.4 mV. NP were spherical, polydisperse and average size was 16.5 ± 6.2 nm. Antifungal activity of Ag NP was assessed by poisoned food technique and resazurin broth dilution against mycelium and sclerotia of fungus R. solani, the causative agent of sheath blight disease in rice. Results confirmed effective hyphal growth inhibition and % growth inhibition was dose dependent (2.5-10 μg/mL). Ag NP showed enhanced mycelial inhibition (81.7-96.7 %) at 10 μg/mL. MIC values of Ag NP were in the range of 5-10 and 15-20 μg/mL towards fungal mycelium and sclerotia, respectively. Ag NP treatment (20 μg/mL) completely inhibited the disease incidence at 20 μg/mL. Ag NP treatment (10 μg/mL) caused 1.3 and 1.5 times enhancement in seedling vigor index. Hence, Ag NP can be utilized towards management and control of various fungal diseases of crops.Monacolin K is a secondary metabolite of Monascus and is known to decrease cholesterol levels in humans. There are 9 genes (mokA-mokI) controlling its biosynthesis, of which mokH is thought to act as a pathway-specific regulator. In this study, the Monascus purpureus M1 strain was compared with mokH gene deletion strains (△H1) and overexpression strains (H7). The monacolin K yields in the △H1 strain were reduced by 52.05 %, and increased in the H7 strain by 82 %. The mycelium samples of the M1, △H1, and H7 strains were found to vary with scanning electron microscopy. Compared to the M1 strain, some mycelium of the △H1 strain showed obvious folding and expansion, while the mycelium of the H7 strain was fuller. Besides, these results indicate that the mokH gene can increase the yield of monacolin K by regulating the expression level of mokA-mokI genes, and influence the production of Monascus pigment. The study is the first to combine deletion and overexpression techniques to further verify the mokH gene and get the desired results in M. purpureus.UDP-glucose pyrophosphorylase (UGP, EC 2.7.7.9) is an essential enzyme involved in carbohydrate metabolism. In Saccharomyces cerevisiae and other fungi, the UGP gene is indispensable for normal cell development, polysaccharide synthesis, and stress response. However, the function of the UGP homolog in plant pathogenic fungi has been rarely explored during pathogenesis. In this study, we characterize a UGP homolog named VdUGP from Verticillium dahliae, a soil-borne fungus that causes plant vascular wilt. In comparison with wild-type strain V07DF2 and complementation strains, the VdUGP knocked down mutant 24C9 exhibited sensitivity to sodium dodecyl sulfate (perturbing membrane integrity) and high sodium chloride concentration (high osmotic pressure stress). More than 25 % of the conidia of the mutant developed into short and swollen hypha and formed hyperbranching and compact colonies. The mutant exhibited decreased virulence on cotton and tobacco seedlings. Further investigation determined that the germination of the mutant spores was significantly delayed compared with the wild-type strain on the host roots. RNA-seq analysis revealed that a considerable number of genes encoding secreted proteins and carbohydrate-active enzymes were significantly downregulated in the mutant at an early stage of infection compared with those of the wild-type strain. RNA-seq data indicated that mutation affected many Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways both in the pathogen and in the inoculated plants at the infection stage. These alterations of the mutant in cultural phenotypes, virulence, and gene expression profiles clearly indicated that VdUGP played important roles in fungal cell morphogenesis, stress responses, and host infection.Yeasts associated with rotting wood from four Atlantic Rain forest sites in Brazil were investigated using a culture medium based on sugarcane bagasse hydrolysate. A total of 330 yeast strains were isolated. Pichia manshurica, Candida pseudolambica, and Wickerhamomyces sp. 3 were the most frequently isolated species. Fourteen novel species were obtained in this study. All isolates were tested for their ability to ferment d-xylose and to produce xylanases. In the fermentation assays using d-xylose (30 g L-1), the main ethanol producers were Scheffersomyces stipitis (14.08 g L-1), Scheffersomyces sp. (7.94 g L-1) and Spathaspora boniae (7.16 g L-1). Sc. stipitis showed the highest ethanol yield (0.42 g g-1) and the highest productivity (0.39 g L-1h-1). The fermentation results using hemicellulosic hydrolysate showed that Sc. stipitis was the best ethanol producer, achieving a yield of 0.32 g g-1, while Sp. boniae and Scheffersomyces sp. were excellent xylitol producers. The best xylanase-producing yeasts at 50 °C belonged to the species Su.