Isolation, Identification and Enzymatic Activity of Halotolerant and Halophilic Fungi from the Great Sebkha of Oran in Northwestern of Algeria

The Great Sebkha of Oran is a closed depression located in northwestern of Algeria. Despite the ranking of this sebkha among the wetlands of global importance by Ramsar Convention in 2002, no studies on the fungal community in this area have been carried out. In our study, samples were collected from two different regions. The first region is characterized by halophilic vegetation and cereal crops and the second by a total absence of vegetation. The isolated strains were identified morphologically then by molecular analysis. The biotechnological interest of the strains was evaluated by testing their ability to grow at different concentration of NaCl and to produce extracellular enzymes (i.e., lipase, amylase, protease, and cellulase) on solid medium. The results showed that the soil of sebkha is alkaline, with the exception of the soil of cereal crops that is neutral, and extremely saline. In this work, the species Gymnoascus halophilus, Trichoderma gamsii, the two phytopathogenic fungi, Fusarium brachygibbosum and Penicillium allii, and the teleomorphic form of P. longicatenatum observed for the first time in this species, were isolated for the first time in Algeria. The halotolerance test revealed that the majority of the isolated are halotolerant. Wallemia sp. and two strains of G. halophilus are the only obligate halophilic strains. All strains are capable to secrete at least one of the four tested enzymes. The most interesting species presenting the highest enzymatic index were Aspergillus sp. strain A4, Chaetomium sp. strain H1, P. vinaceum, G. halophilus, Wallemia sp. and Ustilago cynodontis.

Advance in glycolipid biosurfactants--mannosylerythritol lipids / 生物工程学报

Mannosylerythritol lipids (MELs), mainly produced by Ustilago and Pseudozyma, are surface active compounds that belong to the glycolipid class of biosurfactants. MELs have potential application in food, pharmaceutical and cosmetics industries due to their excellent surface activities and other peculiar bioactivities. In recent years, the research field of MELs has regained much attention abroad. However, MELs are rarely studied in China. In this review, the producing microorganisms and production conditions, diverse structures, biochemical properties, structure-function relationship and biosynthetic pathways of MELs are described. Some research problems and prospects are summarized and discussed as well.

Identification of disease resistance to Ustilago coicis in southern Coix germplasm / 中国中药杂志

<p><b>OBJECTIVE</b>To identified the resistance of Coix to Ustilago coicis and screen the high disease-resistance Coix germplasm.</p><p><b>METHOD</b>Field and laboratory biochemical methods were used for the resistance identification. Ninteen germplasms collected from 7 provinces in southern of China such as Yunnan, Zhejiang, Fujian etc. were inoculated with chlamydospore of U. coicis, respectively. The incidence of a disease in field was investigated and the level of resistance was evaluated. The PAL activity dynamic changes in different level resistant germplasms were further determined.</p><p><b>RESULT</b>The result of field test showed 1 germplasm was immune, 1 germplasm was high resistance which incidence rate was under 20%, 6 germplasms were moderate resistance with the average incidence rates ranged within 20% - 40%, 11 of 19 germplasms that average incidence rates above 40% were identified as sensitive resistance. The value of PLA activity peak of resistant germplasm in seedling was significant higher and appeared earlier than that of the sensitive ones after inoculating.</p><p><b>CONCLUSION</b>Most collected C. lacryma-jobi germplasms are sensitive to smut in our investigation; the PAL activity may play important role in Coix germplasm for resistance to smut and the biochemical method may be as an aiding method to resistance identification of Coix germplasm.</p>

SCGPred: a score-based method for gene structure prediction by combining multiple sources of evidence / 基因组蛋白质组与生物信息学报·英文版

Predicting protein-coding genes still remains a significant challenge. Although a variety of computational programs that use commonly machine learning methods have emerged, the accuracy of predictions remains a low level when implementing in large genomic sequences. Moreover, computational gene finding in newly sequenced genomes is especially a difficult task due to the absence of a training set of abundant validated genes. Here we present a new gene-finding program, SCGPred, to improve the accuracy of prediction by combining multiple sources of evidence. SCGPred can perform both supervised method in previously well-studied genomes and unsupervised one in novel genomes. By testing with datasets composed of large DNA sequences from human and a novel genome of Ustilago maydi, SCG-Pred gains a significant improvement in comparison to the popular ab initio gene predictors. We also demonstrate that SCGPred can significantly improve prediction in novel genomes by combining several foreign gene finders with similarity alignments, which is superior to other unsupervised methods. Therefore, SCG-Pred can serve as an alternative gene-finding tool for newly sequenced eukaryotic genomes. The program is freely available at http://bio.scu.edu.cn/SCGPred/.

Analysis of gene structure, cloning and expression of cyp51 from Ustilago maydis / 生物工程学报

The cyp51 primers and two pairs of mutant primers which removed different transmembrane region were designed based on Ustilago maydis cyp51 gene structure analysis. The full cyp51 DNA fragment as well as mutant cyp51 genes were amplified and cloned by using the total DNA from Ustilago maydis as template, then subcloned into different expression vectors. The recombinant expression plasmids were transformed into Escherichia coli BL21 (DE3), BL21 (DE3) pLysS and Rosetta (DE3) respectively. A series of experiments leads to the finding that only pET32-YH-35 could be highly expressed at the optimal condition of 30 degrees C induced with 0.5 mmol/L IPTG The expressed protein (CYP51) showed biological activity by spectra analysis of the protein binding to 4 standard fungicides and to 14 XF-synthetic fungicide compounds, and only one XF-synthetic fungicide compound (XF-113) was similar to standard fungicides in binding constant. This compound is promising to be a new effective antifungal drug. These results will facilitate the further study on the mechanism of pathogenic fungi CYP51 and pesticide molecules, and will provide a new idea for efficient design and development of new anti-fungal drugs.

Antifungal Activity of Narceine Methyl Ester and Narceine Isolated from Corydalis longipes Against Some Phytopathogenic Fungi

Narceine methyl ester and narceine are potent alkaloids which were isolated from Corydalis longipes were found effective in vitro at very low concentration, i.e., 100~500 ppm against spore germination of some test plant pathogenic fungi (Alternaria solani, A. tagetica, Cercospora abelmoschi, Curvularia maculans, Erysiphe cichoracearum, E. pisi, Fusarium udum, Helminthosporium oryzae, H. penniseti, Ustilago cynodontis). Among the test, phytopathogens the spores of F. udum, C. maculans and H. penniseti were highly sensitive at 200 ppm. However, spores of E. pisi, A. solani and A. tagetica were less sensitive at low concentration followed by other test fungi. Most of the fungi showed zero or nearly zero percent spore germination at 400 and 500 ppm.