13,732 research outputs found

    Penggunaan Beberapa Medium Semisintetik Untuk Produksi Miselium Jamur Maitake (Grifola Frondosa (Dickson: Fr.) S. F. Gray) Isolat Cianjur Dan Ekstrak Kasarnya

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    Research on the use of some semisynthetic medium for the production of fungal mycelium Maitake (Grifola frondosa (dickson: Fr.) SF Gray) isolates Cianjur and crude extract was performed with an incubation period of 30 days. This study aimed to determine the ability of green bean, cowpea and maize as an alternative material of semisynthetic medium for manufacturing G. frondosa\u27s mycelium and and to know the production of G. frondosa\u27s mycelium and the highest crude extract. This study was experimental study with a completely randomized design consisted of 4 treatments : Yeast Potato Dextrose Broth (PDYB) medium, Green bean Yeast Dextrose Broth (GbDYB) medium, Cowpea Yeast Dextrose Broth (CpDYB) medium and Corn Yeast Dextrose Broth (CDYB) medium. The highest average dry weight of mycelium (1,584 g/100ml) was GbDYB medium. The lowest average dry weight of the mycelium (g/100ml 0.244) was PDYB medium. The weight of the crude extract of mycelium in each treatment was lower than the dry weight. The highest weight of the crude extract was obtained from the GbDYB medium treatment (1,22 g) and the lowest was obtained from PDYB medium (0,113 g). Anova test results of different treatment was very significant, meaning that the use of extract of green bean, cowpea and maize greatly affected the growth of G.frondosa\u27s mycelium. The LSD test between treatment of PDYB medium and CDYB medium was not significant, meaning that the increase of mycelium\u27s growth on PDYB medium had no different with the CDYB medium

    Internuclear gene silencing in Phytophthora infestans is established through chromatin remodelling

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    In the plant pathogen Phytophthora infestans, nuclear integration of inf1 transgenic DNA sequences results in internuclear gene silencing of inf1. Although silencing is regulated at the transcriptional level, it also affects transcription from other nuclei within heterokaryotic cells of the mycelium. Here we report experiments exploring the mechanism of internuclear gene silencing in P. infestans. The DNA methylation inhibitor 5-azacytidine induced reversion of the inf1-silenced state. Also, the histone deacetylase inhibitor trichostatin-A was able to reverse inf1 silencing. inf1-expression levels returned to the silenced state when the inhibitors were removed except in non-transgenic inf1-silenced strains that were generated via internuclear gene silencing, where inf1 expression was restored permanently. Therefore, inf1-transgenic sequences are required to maintain the silenced state. Prolonged culture of non-transgenic inf1-silenced strains resulted in gradual reactivation of inf1 gene expression. Nuclease digestion of inf1-silenced and non-silenced nuclei showed that inf1 sequences in silenced nuclei were less rapidly degraded than non-silenced inf1 sequences. Bisulfite sequencing of the endogenous inf1 locus did not result in detection of any cytosine methylation. Our findings suggest that the inf1-silenced state is based on chromatin remodelling

    Biocontrol Ability and Action Mechanism of Starmerella bacillaris (Synonym Candida zemplinina) Isolated from Wine Musts against Gray Mold Disease Agent Botrytis cinerea on Grape and Their Effects on Alcoholic Fermentation

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    Gray mold is one of the most important diseases of grapevine in temperate climates. This plant pathogen affects plant growth and reduces wine quality. The use of yeasts as biocontrol agents to apply in the vineyard have been investigated in recent years as an alternative to agrochemicals. In this work, fermenting musts obtained from overripe grape berries, therefore more susceptible to infection by fungal pathogens such as Botrytis cinerea, were considered for the selection of yeasts carrying antifungal activity. Thirty-six isolates were identified as Starmerella bacillaris, a species recently proven to be of enological interest. Among them 14 different strains were studied and antifungal activity against B. cinerea was demonstrated, for the first time, to be present in S. bacillaris species. The production of volatile organic compounds (VOCs), tested in vitro, was found to be the main responsible of S. bacillaris antifungal effects. All the strains were able to reduce B. cinerea decay on wounded grape berries artificially inoculated with gray mold. The colonization level of wound was very high reaching, after 5 days, a concentration of 10(6) cells per ml of grape juice obtained after berry crushing. At this cell concentration S. bacillaris strains were used to ferment synthetic and natural musts. The sequential yeast inoculation, performed by adding S. cerevisiae 48 h after S. bacillaris, was needed to complete sugar consumption and determined a significant increase in glicerol content and a reduction of ethanol and acetic acid concentrations. The high wound colonization ability, found in this work, together with the propensity to colonize grape berry and the interesting enological traits possessed by the selected S. bacillaris strains allow the use of this yeast as biocontrol agent on vine and grape berries with possible positive effects on must fermentation, although the presence of S. cerevisiae is needed to complete the fermentation process. This work introduces new possibilities in wine yeast selection programs in order to identify innovative wine yeasts that are simultaneously antifungal agents in vineyards and alternative wine starters for grape must fermentation and open new perspective to a more integrated strategy for increasing wine quality

    Taxonomy and antimicrobial activities of a new Streptomyces sp. TN17 isolated in the soil from an oasis in Tunis

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    An actinomycete strain referred to as TN17 was screened for its antimicrobial activities. The taxonomic status of this strain was established. The organism was found to have morphological and chemotaxonomic characteristics typical of Streptomycetes. Based on the 16S rRNA nucleotide sequences, Streptomyces sp. TN17 was found to have a relationship with Streptomyces lilaceus, Streptomyces gobitricini and Streptomyces lavendofoliae. Combined analysis of the 16 S rRNA gene sequence (FN687757), phylogenetic analysis, fatty acids profile and physiological tests indicated that there are genotypic and phenotypic differences between TN17 and neighboring Streptomyces species’ neighbors. Therefore, TN17 is a novel species: Streptomyces sp. TN17 (=DSM 42020T=CTM50229T). A cultured extract of this strain inhibits the growth of several Gram positive and Gram negative bacteria and fungi

    Verrucosispora fiedleri sp. nov., an actinomycete isolated from a fjord sediment which synthesizes proximicins

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    A novel filamentous actinobacterial organism, designated strain MG-37T, was isolated from a Norwegian fjord sediment and examined using a polyphasic taxonomic approach. The organism was determined to have chemotaxonomic and morphological properties consistent with its classification in the genus Verrucosispora and formed a distinct phyletic line in the Verrucosispora 16S rRNA gene tree. It was most closely related to Verrucosispora maris DSM 45365T (99.5 % 16S rRNA gene similarity) and Verrucosispora gifhornensis DSM 44337T (99.4 % 16S rRNA gene similarity) but was distinguished from these strains based on low levels of DNA:DNA relatedness (~56 and ~50 %, respectively). It was readily delineated from all of the type strains of Verrucosispora species based on a combination of phenotypic properties. Isolate MG-37T (=NCIMB 14794T = NRRL-B-24892T) should therefore be classified as the type strain of a novel species of Verrucosispora for which the name Verrucosispora fiedleri is proposed

    Production, Properties And Applications Of Mycelium-Bound Lipase Of A Locally Isolated Strain Of Aspergillus Flavus Link

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    One of the most promising processes using lipase which will offer great potential application especially in term of cost reduction, is the use of mycelium-bound lipase (naturally immobilized lipase). However, there has been little work reported on the technology using mycelium-bound lipase (naturally immobilize) and work using it, is limited to a few microorganisms. This study was conducted with the aims to identifying a new source of mycelium-bound lipase, and consequently to study it's production, properties and applications.Aspergillus flavus, isolated from copra meal, produces a lipase (EC 3.1.1.3) which is partly bound to the mycelium. The production of the mycelium-bound lipase is concomitant with growth, and declines when growth ceases. Maximum productivity of the enzyme is obtained when the culture is incubated at 30°C, an initial culture pH of 6.5 and with 2% (w/v) each of com oil and yeast extract as carbon and organic nitrogen sources, respectively. Yeast extract affects not only the production of lipase but also the secretion of proteases into the culture medium. The presence of EDTA improved the productivity of the mycelium-bound lipase by 26% although growth of A. flavus was inhibited by 11%. The addition of Tween 80, into culture medium, decreased the activity of mycelium-bound lipase

    Biocommunication of Fungal Organisms

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    The development and growth of fungal organisms depend on successful communication processes (a) within the organism and between organisms, (b) with the same or related species and (c) with non-related organisms. In order to generate an appropriate response behaviour, fungal organisms must also be able to (d) correctly interpret meaningful information from the abiotic environment. However, these communication and interpretation processes can also fail. In such cases the overall results can induce disease-causing and even lethal consequences for the organism. 

	This review will not enrich the knowledge of specialists in fungal research, but will demonstrate to a broader readership the different levels of fungal communication and how versatile fungal communicative competences really are. Interestingly, certain rules of fungal communication are very similar to those of animals, while others resemble those of plants. The correspondence between all three eukaryotic kingdoms has two aspects: (1) the context determines the meaning of trans-, inter- and intra-organismic (inter- and intracellular) communication, while (2) differences in abiotic and biotic signal perception determine the content arrangement of response behaviour

    Analysis of fungal type isolates taken from a 90-day manned test of an advanced regenerative life support system

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    Fungal-like cultures isolated before, during, and after the 90-day test from samples of space station simulator (SSS) atmosphere, surfaces, subsystem componets, and crew dermal sites were identified to genus. Out of the original 525 isolates, approximately 80% were classified as bacteria. Laboratory methods (culture media, moisturization, and incubation temperatures) favored the recovery of medically significant bacteria rather than fungi. Therefore, fungal isolates were mostly, nonfastidious types which are ubiquitous in soil and air and commonly contaminate laboratory cultures of pathogens. Predominant isolates were species of Aspergillus, Penicillium, Pullularia, Rhodotorula, and various yeasts. No instances of fungal proliferation were observed; test data reflect the survival of environmental types indigenous to the SSS pretests
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