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Microbial Origin (microbial + origin)
Selected AbstractsLow-Molecular-Weight Poly(, -methyl ,,L -malate) of Microbial Origin: Synthesis and CrystallizationMACROMOLECULAR BIOSCIENCE, Issue 2 2005Carlos E. Fernández Abstract Summary: Low-molecular-weight poly(, -methyl ,,L -malate) made of approximately 25,30 units was prepared from microbial poly(,,L -malic acid) by treatment with diazomethane. The thermal characterization of the polymalate methyl ester was carried out and its crystalline structure was preliminary examined. Its ability to crystallize both from solution and from the melt was comparatively evaluated. Poly(, -methyl ,,L -malate) spherulitic film cast from CHCl3. [source] What do dung beetles eat?ECOLOGICAL ENTOMOLOGY, Issue 6 2007PETER HOLTER Abstract 1.,Most adult coprophagous beetles feed on fresh dung of mammalian herbivores, confining ingestion to small particles with measured maximum diameters from 2,5 to 130 ,m, according to body size and kind of beetle. This study explores benefits and costs of selective feeding in a ,typical' dung beetle with a maximum diameter of ingested particles (MDIP) of 20 ,m. 2.,Examined dung types (from Danish domestic sheep, cattle and horse, and African wild buffalo, white rhino and elephant) contained 76,89% water. Costs of a 20 ,m MDIP were often low, since 69,87% of the total nitrogen in bulk dung other than that of elephant and rhino (40,58%) was available to selective feeders. 3.,Nitrogen concentrations were high , and C/N ratios low , in most types of bulk dung compared with the average food of terrestrial detritivores or herbivores. Exceptions were elephant and rhino dung with low nitrogen concentrations and high C/N ratios. 4.,Estimated C/N ratios of 13,39 in bulk dung (sheep,elephant) were decreased by selective feeding to 7.3,12.6 in the ingested material. In assimilated food, ratios are probably only 5,7, as most assimilable nitrogen and carbon may be of microbial origin. If so, the assimilable food contains a surplus of nitrogen relative to carbon. 5.,The primary advantage of selective feeding, particularly in dung with a high C/N ratio, may be to concentrate assimilable carbon in the ingested food. Effects of changing the MDIP within 20,106 ,m are modest, especially in dung with a low C/N ratio. [source] Bacteria associated with the rapid tissue necrosis of stony coralsENVIRONMENTAL MICROBIOLOGY, Issue 7 2007G. M. Luna Summary The rapid tissue necrosis (RTN) is a common disease of both wild and captive stony corals, which causes a fast tissue degradation (peeling) and death of the colony. Here we report the results of an investigation carried out on the stony coral Pocillopora damicornis, affected by an RTN-like disease. Total abundance of prokaryotes in tissue samples, determined by epifluorescence microscopy, was significantly higher in diseased than in healthy corals, as well as bacterial counts on MB2216 agar plates. Further experiments performed by fluorescent in situ hybridization using a 16S rDNA Vibrio -specific probe showed that vibrios were significantly more abundant in diseased than in healthy corals. Accordingly, bacterial counts on TCBS agar plates were higher in diseased than in healthy tissues. 16S rDNA sequencing identified as Vibrio colonies from diseased tissues only. Cultivated vibrios were dominated by a single ribotype, which displayed 99% of similarity with Vibrio harveyi strain LB4. Bacterial ribotype richness, assessed by terminal-restriction fragment length polymorphism analysis of the 16S rDNA, was significantly higher in diseased than in healthy corals. Using an in silico software, we estimated that a single terminal restriction fragment, putatively assigned to a Vibrio sp., accounted for >,15% and < 5% of the total bacterial assemblage, in diseased and healthy corals respectively. These results let us hypothesize that the RTN in stony corals can be an infectious disease associated to the presence of Vibrio harveyi. However, further studies are needed to validate the microbial origin of this pathology. [source] Nonlysine-analog plasminogen modulators promote autoproteolytic generation of plasmin(ogen) fragments with angiostatin-like activityFEBS JOURNAL, Issue 4 2004Shigeki Ohyama We recently discovered several nonlysine-analog conformational modulators for plasminogen. These include SMTP-6, thioplabin B and complestatin that are low molecular mass compounds of microbial origin. Unlike lysine-analog modulators, which increase plasminogen activation but inhibit its binding to fibrin, the nonlysine-analog modulators enhance both activation and fibrin binding of plasminogen. Here we show that some nonlysine-analog modulators promote autoproteolytic generation of plasmin(ogen) derivatives with its catalytic domain undergoing extensive fragmentation (PMDs), which have angiostatin-like anti-endothelial activity. The enhancement of urokinase-catalyzed plasminogen activation by SMTP-6 was followed by rapid inactivation of plasmin due to its degradation mainly in the catalytic domain, yielding PMD with a molecular mass ranging from 68 to 77 kDa. PMD generation was observed when plasmin alone was treated with SMTP-6 and was inhibited by the plasmin inhibitor aprotinin, indicating an autoproteolytic mechanism in PMD generation. Thioplabin B and complestatin, two other nonlysine-analog modulators, were also active in producing similar PMDs, whereas the lysine analog 6-aminohexanoic acid was inactive while it enhanced plasminogen activation. Peptide sequencing and mass spectrometric analyses suggested that plasmin fragmentation was due to cleavage at Lys615-Val616, Lys651-Leu652, Lys661-Val662, Lys698-Glu699, Lys708-Val709 and several other sites mostly in the catalytic domain. PMD was inhibitory to proliferation, migration and tube formation of endothelial cells at concentrations of 0.3,10 µg·mL,1. These results suggest a possible application of nonlysine-analog modulators in the treatment of cancer through the enhancement of endogenous plasmin(ogen) fragment formation. [source] Effects of bio-pesticides on Eretmocerus warrae (Hym., Aphelinidae), a parasitoid of Bemisia tabaci (Hom., Aleyrodidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2008P. Kumar Abstract The sweet potato whitefly Bemisia tabaci (WF) can be controlled by two commercial neem products, NeemAzal-T/S® (1% azadirachtin) for foliar application, and NeemAzal-U (17% azadirachtin) for soil application, alongwith two biorational products of microbial origin, Abamectin (avermectin) and Success® (spinosad). Side effects of these products were tested in a laboratory bioassay against a native aphelinid, Eretmocerus warrae (EW). Eggs and early larval instars of the parasitoid, commonly found outside the host body, were highly susceptible to foliar spray of neem with only 8%, 18% and 55% emergences of adults from treated eggs. larval and pupal stages respectively at recommended dose-rates of 5 ml/l and 1%, 8% and 40% at twice recommend dose-rate (10 ml/l). Soil application with NeemAzal-U marginally affected EW. At highest tested dose-rate of 3.0 g/l, 46%, 64% and 81% emergence was recorded after treatement of plants harbouring WF parasitized by egg, larval and pupal stages of EW respectively. In contrast to neem application, Success® and Abamectin caused high mortality in development stages of the parasitoids. In particular, abamectin was highly toxic to the parasitoids with less than 1% emergence from either of the three development stages if treated with 1,2 ml/l. [source] Potential of bacterial indoleacetic acid to induce adventitious shoots in plant tissue cultureLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2007B. Ali Abstract Aims:, The main aim of this study was to investigate the possible role of indoleacetic acid (IAA) from bacteria to induce in vitro adventitious shoots in internodal explants of Brassica oleracea L. Methods and Results:, Culture supernatant of Halomonas sp. RE1 and Halomonas sp. HT1 that contain 21 and 40 ,g ml,1 IAA, respectively, was used to supplement Murashige and Skoog (MS) medium. Two combinations that were supplemented with bacterial supernatant (BS) are MS + BS and MS + BS + 10%CW (coconut water) while basal MS medium was used as control. The amounts of BS used in this experiment were 50, 100, 150 and 200 ,l in 5 ml MS medium in each combination. In vitro -grown internodal explants of B. oleracea were inoculated on these media combinations and incubated in a growth chamber at 25 ± 1°C and exposed to 16-h cool fluorescent light. After 5,6 weeks of incubation adventitious shoot induction was observed in all treatments that were supplemented with BS as compared with the controls where very low response was observed. The frequency of shoot induction was high in media that were supplemented with 10%CW in the presence of bacterial auxin. Conclusions:, It was concluded that IAA of microbial origin has the potential to induce adventitious shoots in internodal explants. Significance and Impact of the Study:, IAA from bacteria can be effectively used in plant tissue culture; especially a combination of MS + BS + 10%CW is very cost-effective as compared with synthetic phytohormones for in vitro studies. [source] Binase and other microbial RNases as potential anticancer agentsBIOESSAYS, Issue 8 2008Alexander A. Makarov Some RNases possess preferential cytotoxicity against malignant cells. The best known of these RNases, onconase, was isolated from frog oocytes and is in clinical trials as anticancer therapy. Here we propose an alternative platform for anticancer therapy based on T1 RNases of microbial origin, in particular binase from Bacillus intermedius and RNase Sa from Streptomyces aureofaciens. We discuss their advantages and the most promising directions of research for their potential clinical applications. BioEssays 30:781,790, 2008. © 2008 Wiley Periodicals, Inc. [source] Control of Pathogenic and Spoilage Microorganisms in Fresh-cut Fruits and Fruit Juices by Traditional and Alternative Natural AntimicrobialsCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 3 2009Rosa M. Raybaudi-Massilia ABSTRACT:, Traditional antimicrobials have been extensively used for many years. However, consumers are currently demanding wholesome, fresh-like, and safe foods without addition of chemically synthesized preservatives. The application of novel natural antimicrobials to assure safety of fresh-cut fruits and unpasteurized juices while preventing quality loss is a promising alternative. The effectiveness of these natural substances added to fruit derivatives has been studied by different researchers. Antimicrobials of animal (lactoperoxidase, lysozyme, and chitosan), plant (essential oils, aldehydes, esters, herbs, and spices), and microbial origin (nisin) can be used to effectively reduce pathogenic and spoilage microorganisms in fresh-cut fruits and fruit juices. Nevertheless, the use of these compounds at a commercial level is still limited due to several factors such as impact on sensory attributes or, in some cases, regulatory issues concerning their use. Therefore, extensive research on the effects of each antimicrobial on food sensory characteristics is still needed so that antimicrobial substances of natural origin can be regarded as feasible alternatives to synthetic ones. [source] | ||||||||||