To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and ad...To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution(50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth(1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth) on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter(DM) and crude protein(CP) concentrations, lower neutral detergent fiber(NDF), acid detergent fiber(ADF) and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM(IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.展开更多
Phytochemical reinvestigation on the cultural broth of Boreostereum vibrans led to the isolation of six new vibralactone derivatives,vibralactone N(1),vibralactone O(2),vibralactone P(3),10-lactyl vibralactone G(4),(3...Phytochemical reinvestigation on the cultural broth of Boreostereum vibrans led to the isolation of six new vibralactone derivatives,vibralactone N(1),vibralactone O(2),vibralactone P(3),10-lactyl vibralactone G(4),(3S*,4R*)-6-acetoxymethyl-2,2-dimethyl-3,4-dihydro-2H-chromene-3,4-diol(5),vibralactone Q(6).Their structures were elucidated by extensive spectroscopic methods.展开更多
<em>Background:</em> Antisense peptide nucleic acids (PNAs) exhibit growth inhibitory effects on bacteria by inhibiting the expression of essential genes and could be promising therapeutic agents for treat...<em>Background:</em> Antisense peptide nucleic acids (PNAs) exhibit growth inhibitory effects on bacteria by inhibiting the expression of essential genes and could be promising therapeutic agents for treating bacterial infections. A study was carried out to determine the efficacy of several antisense PNAs in inhibiting extracellular and intracellular growth of <em>Mycobacterium smegmatis</em>. <em>Methods: </em>Six PNAs obtained from a commercial supplier were tested to evaluate the inhibitory effect on bacterial growth by inhibiting the expression of the following essential genes: <em>inhA </em>(a fatty acid elongase), <em>rpsL</em> (ribosomal S12 protein), <em>gyrA</em> (DNA gyrase), <em>pncA</em> (pyrazinamidase), <em>polA</em> (DNA polymerase I) and <em>rpoC</em> (RNA polymerase <em>β</em> subunit) of <em>M. smegmatis</em>. Each PNA was tested at 20 μM, 10 μM, 5 μM and 2.5 μM concentrations to determine whether they caused a dose dependent killing of <em>M. smegmatis</em> cultured in Middlebrook 7H9 broth or in a J774A.1 murine macrophage cell line.<em> Results:</em> In Middlebrook broth, the strong growth inhibitory effect against <em>M. smegmatis</em> was observed by PNAs targeting the <em>inhA </em>and <em>rpsL</em> genes at all four concentrations. The PNAs targeting the<em> pncA</em>, <em>polA</em> and<em> rpoC</em> genes were found to exhibit strong growth inhibition against <em>M. smegmatis</em> but only at 20 μM concentration. No growth inhibition of <em>M. smegmatis </em>was seen in pure culture when treated with PNAs targeting gyrA and a mismatch PNA targeting dnaG (DNA primase). All six PNAs showed killing of <em>M. smegmatis </em>in J774A.1 macrophage cell line that were statistically significant (p < 0.05). <em>Conclusion:</em> It may be concluded from this study that PNAs could be potential therapeutics for mycobacterial infections.展开更多
基金supported by the National Key Technology Research and Development Program of China during the 12th Five-Year Plan period (2012BAD14B01)the Special Fund for Agro-Scientific Research in the Public Interest, China (201303080)
文摘To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution(50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth(1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth) on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter(DM) and crude protein(CP) concentrations, lower neutral detergent fiber(NDF), acid detergent fiber(ADF) and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM(IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.
基金This work was financially supported by National Natural Science Foundation of China(81102348).
文摘Phytochemical reinvestigation on the cultural broth of Boreostereum vibrans led to the isolation of six new vibralactone derivatives,vibralactone N(1),vibralactone O(2),vibralactone P(3),10-lactyl vibralactone G(4),(3S*,4R*)-6-acetoxymethyl-2,2-dimethyl-3,4-dihydro-2H-chromene-3,4-diol(5),vibralactone Q(6).Their structures were elucidated by extensive spectroscopic methods.
文摘<em>Background:</em> Antisense peptide nucleic acids (PNAs) exhibit growth inhibitory effects on bacteria by inhibiting the expression of essential genes and could be promising therapeutic agents for treating bacterial infections. A study was carried out to determine the efficacy of several antisense PNAs in inhibiting extracellular and intracellular growth of <em>Mycobacterium smegmatis</em>. <em>Methods: </em>Six PNAs obtained from a commercial supplier were tested to evaluate the inhibitory effect on bacterial growth by inhibiting the expression of the following essential genes: <em>inhA </em>(a fatty acid elongase), <em>rpsL</em> (ribosomal S12 protein), <em>gyrA</em> (DNA gyrase), <em>pncA</em> (pyrazinamidase), <em>polA</em> (DNA polymerase I) and <em>rpoC</em> (RNA polymerase <em>β</em> subunit) of <em>M. smegmatis</em>. Each PNA was tested at 20 μM, 10 μM, 5 μM and 2.5 μM concentrations to determine whether they caused a dose dependent killing of <em>M. smegmatis</em> cultured in Middlebrook 7H9 broth or in a J774A.1 murine macrophage cell line.<em> Results:</em> In Middlebrook broth, the strong growth inhibitory effect against <em>M. smegmatis</em> was observed by PNAs targeting the <em>inhA </em>and <em>rpsL</em> genes at all four concentrations. The PNAs targeting the<em> pncA</em>, <em>polA</em> and<em> rpoC</em> genes were found to exhibit strong growth inhibition against <em>M. smegmatis</em> but only at 20 μM concentration. No growth inhibition of <em>M. smegmatis </em>was seen in pure culture when treated with PNAs targeting gyrA and a mismatch PNA targeting dnaG (DNA primase). All six PNAs showed killing of <em>M. smegmatis </em>in J774A.1 macrophage cell line that were statistically significant (p < 0.05). <em>Conclusion:</em> It may be concluded from this study that PNAs could be potential therapeutics for mycobacterial infections.