586 research outputs found

    Integrativna ekspresija gena za glukoamilazu u soju pivskoga kvasca Saccharomyces pastorianus

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    The recombinant brewer’s yeast Saccharomyces pastorianus strain was constructed byintroducing the ilv2:GLA fragment released from pMGI6, carrying glucoamylase gene (GLA) and using the yeast α-acetolactate synthase gene (ILV2) as the recombination sequence. The strain was able to utilise starch as the sole carbon source, its glucoamylase activity was 6.3 U/mL and its α-acetolactate synthase activity was lowered by 33.3 %. The introduced GLA gene was integrated at the recipient genomic ILV2 gene, one copy of ILV2 gene was disrupted and the other copy remained intact. Primary wort fermentation test confirmed that the diacetyl and residual sugar concentration in the wort fermented by the recombinant strain were reduced by 65.6 and 34.2 % respectively, compared to that of the recipient strain. Under industrial operating conditions, the maturation time of beer fermented by the recombinant strain was reduced from 7 to 4 days, there were no significant differences in the appearance and mouthfeel, and the beer satisfied the high quality demands. That is why the strain could be used in beer production safely.Uvođenjem ilv2:GLA isječka iz pMGI6, kao nosioca gena za glukoamilazu (GLA) i uporabom rekombinacijske sekvencije gena za α-acetolaktat sintazu (ILV2), konstruiran je rekombinantni soj pivskoga kvasca Saccharomyces pastorianus. Utvrđeno je da soj može koristiti škrob kao jedini izvor ugljika, da aktivnost glukoamilaze iznosi 6,3 U/mL, a da je aktivnost α-acetolaktat sintaze smanjena za 33,3 %. Uvedeni gen GLA, integriran u gen primatelja ILV2, raskinuo je jednu kopiju gena ILV2, dok je druga kopija ostala nepromijenjena. Prvi test fermentacije sladovine potvrdio je da je fermentacijom s pomoću rekombinantnog soja koncentracija diacetila smanjena za 65,6 %, a koncentracija ostatka šećera za 34,2 % u usporedbi sa sojem primatelja. U industrijskim uvjetima zrenje piva fermentiranog s pomoću rekombinantnog soja smanjeno je sa 7 na 4 dana, pri čemu nema značajne razlike u izgledu i okusu, te je ono zadovoljilo visoke zahtjeve. Stoga se ovaj soj može sigurno upotrijebiti u proizvodnji piva

    Integrativna ekspresija gena za glukoamilazu u soju pivskoga kvasca Saccharomyces pastorianus

    Get PDF
    The recombinant brewer’s yeast Saccharomyces pastorianus strain was constructed byintroducing the ilv2:GLA fragment released from pMGI6, carrying glucoamylase gene (GLA) and using the yeast α-acetolactate synthase gene (ILV2) as the recombination sequence. The strain was able to utilise starch as the sole carbon source, its glucoamylase activity was 6.3 U/mL and its α-acetolactate synthase activity was lowered by 33.3 %. The introduced GLA gene was integrated at the recipient genomic ILV2 gene, one copy of ILV2 gene was disrupted and the other copy remained intact. Primary wort fermentation test confirmed that the diacetyl and residual sugar concentration in the wort fermented by the recombinant strain were reduced by 65.6 and 34.2 % respectively, compared to that of the recipient strain. Under industrial operating conditions, the maturation time of beer fermented by the recombinant strain was reduced from 7 to 4 days, there were no significant differences in the appearance and mouthfeel, and the beer satisfied the high quality demands. That is why the strain could be used in beer production safely.Uvođenjem ilv2:GLA isječka iz pMGI6, kao nosioca gena za glukoamilazu (GLA) i uporabom rekombinacijske sekvencije gena za α-acetolaktat sintazu (ILV2), konstruiran je rekombinantni soj pivskoga kvasca Saccharomyces pastorianus. Utvrđeno je da soj može koristiti škrob kao jedini izvor ugljika, da aktivnost glukoamilaze iznosi 6,3 U/mL, a da je aktivnost α-acetolaktat sintaze smanjena za 33,3 %. Uvedeni gen GLA, integriran u gen primatelja ILV2, raskinuo je jednu kopiju gena ILV2, dok je druga kopija ostala nepromijenjena. Prvi test fermentacije sladovine potvrdio je da je fermentacijom s pomoću rekombinantnog soja koncentracija diacetila smanjena za 65,6 %, a koncentracija ostatka šećera za 34,2 % u usporedbi sa sojem primatelja. U industrijskim uvjetima zrenje piva fermentiranog s pomoću rekombinantnog soja smanjeno je sa 7 na 4 dana, pri čemu nema značajne razlike u izgledu i okusu, te je ono zadovoljilo visoke zahtjeve. Stoga se ovaj soj može sigurno upotrijebiti u proizvodnji piva

    Plasmons in Pb nanowire arrays on Si(557): Between one and two dimensions

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    The plasmon dispersion in arrays of nanowires of Pb close to an average Pb coverage of one monolayer was determined on the Si(557) surface using electron energy loss spectroscopy with both high energy and momentum resolution. While we find purely one-dimensional (1D) plasmon losses at a Pb concentration of 1.31 monolayers (ML), measured with respect to the Si(111) surface concentration, the 1.2 and 1.4 ML coverages exhibit wavelength-dependent transitions from 1D to anisotropic 2D properties. However, due to the high anisotropy in the system at all coverages, the dispersion curves exhibit 1D characteristics in both directions. This behavior seems to be related to the Pb-induced refacetting of the Si(557) surface, which depends on Pb coverage. It changes both effective system sizes and coupling strength between miniterraces. © 2011 American Physical Society.Ministry of Education, Culture, Sports, Science, and Technology, Japa

    Passive Localization of 3D Near-Field Cyclostationary Sources Using Parallel Factor Analysis

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    By exploiting favorable characteristics of a uniform cross-array, a passive localization algorithm of narrowband cyclostationary sources in the spherical coordinates (azimuth, elevation, and range) is proposed. Firstly, we construct a parallel factor (PARAFAC) analysis model by computing the third-order cyclic moment matrices of the properly chosen sensor outputs. Then, we analyze the uniqueness of the constructed model and obtain three-dimensional (3D) near-field parameters via trilinear alternating least squares regression (TALS). The investigated algorithm is well suitable for the localization of the near-field cyclostationary sources. In addition, it avoids the multidimensional search and pairing parameters. Results of computer simulations are carried out to confirm the satisfactory performance of the proposed method

    Joint 2D Direction-of-Arrival and Range Estimation for Nonstationary Sources

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    Passive localization of nonstationary sources in the spherical coordinates (azimuth, elevation, and range) is considered, and a parallel factor analysis based method is addressed for the near-field parameter estimation problem. In this scheme, a parallel factor analysis model is firstly constructed by computing five time-frequency distribution matrices of the properly chosen observation data. In addition, the uniqueness of the constructed model is proved, and both the two-dimensional (2D) direction-of-arrival (DOA) and range can be jointly obtained via trilinear alternating least squares regression (TALS). The investigated algorithm is well suitable for near-field nonstationary source localization and does not require parameter-pairing or multidimensional search. Several simulation examples confirm the effectiveness of the proposed algorithm

    Effects of Salmonella enterica serovar Enteritidis infection on egg production and the immune response of the laying duck Anas platyrhynchos

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    Persistent colonization of the avian reproductive tract by Salmonella enterica serovar Enteritidis (SE) negatively affects egg production and contaminates the egg. The immune function of the ovary and oviduct is essential for protection from infection and for the production of wholesome eggs. However, the immune response of laying ducks during SE infection is not well-understood. In this study, ducks (Anas platyrhynchos) were infected with SE and were systematically monitored for fecal shedding during a 13-week period. We also assessed bacterial distribution in the reproductive tract and classified infected ducks as resistant or susceptible based on the presence of tissue lesions and on SE isolation from fecal samples. We found that infected animals had persistent, but intermittent, bacterial shedding that resulted in the induction of carrier ducks. Laying rate and egg quality were also decreased after SE infection (P < 0.05). SE readily colonized the stroma, small follicle, isthmus, and vagina in the reproductive tracts of susceptible ducks. Immunoglobulin (IgA, IgG, IgM) levels were higher in susceptible ducks compared with resistant birds (P < 0.05); T-lymphocyte subpopulations (CD3+, CD4+, CD8+) displayed the opposite trend. qRT-PCR analysis was used to examine expression profiles of immune response genes in the reproductive tract of infected ducks. The analysis revealed that immune genes, including toll-like receptors (TLR2, TLR4-5, TLR15, TLR21), NOD-like receptors (NOD1, NLRX1, NLRP12), avian β-defensins (AvβD4-5, AvβD7, AvβD12), cytokines (IL-6, IL-1β, IFN-γ), and MyD88 were markedly upregulated in the reproductive tracts of SE-infected ducks (all P < 0.05); TLR3, TLR7, NLRC3, NLRC5, and TNF-α were significantly downregulated. These results revealed that SE infection promoted lower egg production and quality, and altered the expression of TLRs, NLRs, AvβDs, and cytokine family genes. These findings provide a basis for further investigation of the physiological and immune mechanisms of SE infection in laying ducks
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