251 research outputs found

    Uvodnik

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    Uvodnik

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    Predgovor

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    Predgovor

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    BIOCHEMICAL CHARACTERIZATION AND IDENTIFICATION OF PROBIOTIC Lactobacillus FOR SWINE

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    The aim of the present work was to select lactic acid bacteria from the gastrointestinal tract of pigs and establish their biochemical characterization. Strains P01-001 and P08- 002 were selected out of a total of 33 bile resistant strains (5% of bile) because they presented the best survival rate at room temperature and after freeze-drying. Complementary studies on aspects like the ability to grow at different temperatures and resistance to inhibitory substances such as bile 10%, phenol 0.4%, NaCl 4% and 8% were performed. The selected strains P01-001 and P08-002 were identified biochemically through the API 50 test as Lactobacillus and classified as heterofermentative bacteria by gas production from glucose and by the presence of lactic and acetic acids in Man, Rogosa and Sharpe (MRS) supernatants detected by HPLC. The strains P01-001 and P08-002 growing at 45°C and tolerant to 10% bile, 0.4% phenol and 4% NaCl will be studied in animal trials as potential probiotic agents

    Kloniranje, funkcionalna ekspresija i karakterizacija L-asparaginaze II iz E. coli MTCC 739

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    L-Asparaginase is an antineoplastic agent that selectively decreases the level of L-asparagine in blood and diminishes the proliferation of the cancerous cells. L-Asparaginases from Escherichia coli are widely used for clinical application because of their high substrate specificity and limited glutaminase activity. L-Asparaginase II-encoding gene ansB was isolated by excluding the native signal from E. coli MTCC 739, cloned in frame with pelB leader sequence of prokaryotic expression vector pET20b and expressed in E. coli DE3 cells. Overexpression of recombinant protein was achieved with an optimized final concentration of 10 μM of isopropyl β-D-1-thiogalactopyranoside (IPTG). The protein was expressed as soluble protein. The recombinant protein contained hexahistidine tag at C-terminus and was purified using nickel-nitrilotriacetic acid chromatography. Enzymatic properties such as optimum temperature, pH and the effect of temperature on the stability of L-asparaginase II from E. coli MTCC 739 were determined and the purified protein showed an optimum activity at 37 °C and pH=6.L-asparaginaza je antineoplastični agens koji selektivno smanjuje razinu L-asparaginaze u krvi i sprečava proliferaciju kanceroznih stanica. L-asparaginaze iz bakterije Escherichia coli koriste se za klinička ispitivanja zbog njihove specifičnosti za supstrat i ograničene aktivnosti glutaminaze. Gen ansB za kodiranje L-asparaginaze II izoliran je iz E. coli MTCC 739, kloniran pomoću pelB sekvencije prokariotskog vektora pET20b i izražen u stanicama E. coli DE3. Pojačana je ekspresija rekombinantnog proteina postignuta pomoću 10 μM izopropil β-D-1-tiogalaktopiranozidaze, pri čemu je izraženi protein bio topljiv, a na C završetku imao je heksahistidinsku oznaku. Rekombinirani je protein pročišćen kromatografijom pomoću nikal(II)-nitrilotrioctene kiseline. Ispitani su ovi parametri: optimalna temperatura i pH-vrijednost za aktivnost enzima, te utjecaj temperature na njegovu stabilnost. Utvrđeno je da je pročišćeni protein imao optimalnu aktivnost pri 37 °C i pH=6

    MICROBIOTA ISOLADA DURANTE AS FASES DE PRÉ E PÓS-COLHEITA DOS GRÃOS DE CAFÉ ASSOCIADA À QUALIDADE E SANIDADE DA BEBIDA

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    O objetivo desta revisão residiu em compilar dados sobre a microbiota dos grãos de café, visando correlacionála com procedimentos que permitam minimizar a contaminação microbiológica. Foram abordados o cultivo e o processamento dos grãos de café, os microrganismos a eles associados nas fases de pré e pós-colheita, bem como a contaminação por fungos, especificamente o Aspergillus ochraceus (produtor de ocratoxina). Concluiu-se que para manter a sanidade da bebida, a longo prazo, devem ser adotadas boas práticas de produção, porém em curto prazo é necessário buscar alternativas que inibam ou impeçam o desenvolvimento da toxina em grãos armazenados. ISOLATED MICROBIOT DURING PRE AND POST-HARVEST STAGES OF COFFEE GRAINS ASSOCIATED TO QUALITY AND SANITARY CONDITIONS OF THE BEVERAGE Abstract The aim of this review was to aggregate data about coffee grains microbiot, aiming to correlate it with the procedures which allows to minimize the microbiological contamination. The cultivation and processing procedures of coffee grains were described, the microorganisms associated in pre and post harvest stages, as well as the contamination by fungi, specifically Aspergillus ochraceus (producer of ochratoxin). It was concluded that to maintain the sanitary conditions of the beverage, to long term, good manufacturing practices must be adopted, even so in short term it is necessary to search for alternatives that inhibit or impede the toxin development in stored grains

    Advances in Mushroom Research in the Last Decade

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    U posljednjem desetljeću došlo je do značajnog napretka u znanstvenom i biotehnološkom istraživanju gljiva. Optimiranje odjeljivanja kromosoma gljiva metodom PFGE omogućilo je istraživanje njihova molekularnog kariotipa i dodjeljivanje gena pojedinom kromosomu. Postoji 115 gena kodiranih iz različitih vrsta gljiva. Križanje je i dalje glavna metoda, ali se sve češće primjenjuju i RAPD analize ili RFLP metode. Koriste se genetski markeri koji se introgresijom uvode u komercijalne velike hibride. Određena su i u praksi primijenjena kompleksna svojstva kao što su prinos, otpornost na bolesti i kakvoća, te osobine više od jednog lokusa kvantitativnog svojstva (QTL). Pomoću bakterije Agrobacterium ili bombardiranjem čestica dobiveni su transformanti ili transgeni mutageni. Istražena je najmanje 651 vrsta, predstavnika 182 roda gljiva iz razreda Heterobasidiomycetes ili Homobasidiomycetes, koje sadrže polisaharide s antitumorskim ili imunostimulirajućim djelovanjem. Kao jedan od najaktivnijih sastojaka identificiran je ergosterol iz frakcije lipida. Također se kao antimikrobni ili antivirusni agensi intenzivno istražuju novi seskviterpenoidni hidrokinoni, steroidi, oksalna kiselina, triterpeni, lignini topljivi u vodi, sulfatirani polisaharidi te polisaharidi vezani s proteinima. Mnogi spojevi male molekularne mase, poput iludina, leaianfulvena, triterpena (ganoderične kiseline), acetoksiscirpendiola, ergosterol peroksida i sterola, pokazuju citotoksično djelovanje. U gljivama su pronađeni mnogi drugi spojevi koji imaju antioksidativno, hipoglikemičko, protuupalno, hepatoprotektivno ili psihoaktivno djelovanje.There has been a lot of progress in mushroom science and biotechnology in the last decade. The optimization of PFGE separation of fungal chromosomes allowed the study of the molecular karyotype of mushrooms and the assignment of genes to chromosomes. There are 115 genes encoded from different species of mushrooms. Cross breeding continues to be the principal method, but it is accompanied by the analyses of RAPD or RFLPs methods. The genetic makers are used and introduced into commercial large hybrids via introgression breeding. The complex traits such as yield, resistance to disease and quality characteristics, and quantitative traits more than one quantitative trait locus (QTL) are found and used in practice. The transformants or transgenic mutant strains were obtained by Agrobacterium system or particle bombardment. At least 651 species representing 182 genera of hetero- and homobasidiomycetes mushrooms were researched containing antitumor or immunostimulating polysaccharides. Ergosterol in the lipid fraction was identified as one of the most active constituents. New sesquiterpenoid hydroquinones, steroids, oxalic acid, triterpenes, water-soluble lignins, sulfated polysaccharides, protein-bound polysaccharides are researched intensively as antimicrobial or antiviral agents. Many small molecular mass compounds exhibit cytotoxic activities, such as illudins, leaianafulvene, triterpenes (ganoderic acids), acetoxyscirpenediol, ergosterol peroxide, sterols. There are many other compounds or activities found in the mushrooms, such as antioxidative, hypoglycemic action, anti-inflammatory effect, hepatoprotective compounds, psychoactive compounds and activities
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