Subjects: Biology >> Zoology submitted time 2018-12-24 Cooperative journals: 《动物营养学报》
Abstract：本试验以小肽含量为指标，对解淀粉芽孢杆菌单菌固态发酵豆粕以及解淀粉芽孢杆菌、植物乳杆菌和酿酒酵母菌三菌种混菌固态发酵豆粕的工艺条件进行优化，并对其发酵前后的营养物质含量变化进行研究。通过解淀粉芽孢杆菌、植物乳杆菌和酿酒酵母3个试验菌的生长曲线确定其接种到固态培养基的最佳接种时间。采用单因素试验设计研究解淀粉芽孢杆菌接种量、温度、料水比、发酵时间4个因素对豆粕发酵产小肽的影响，并在此基础上采用四因素三水平的正交试验设计对单、混菌固态发酵豆粕的工艺条件进行优化。对豆粕发酵前后豆粕营养物质含量、大豆球蛋白含量、蛋白分子质量、发酵产物pH进行测定。结果显示：3株试验菌接在各自种子培养基扩大培养至21 h为其接种到固态培养基的最佳时间。解淀粉芽孢杆菌单菌固态发酵豆粕的最佳工艺条件为：接种量为10%、温度为40 ℃、料水比为1.0:1.2、发酵时间为72 h；解淀粉芽孢杆菌、植物乳杆菌、酿酒酵母混菌固态发酵豆粕的最佳工艺条件为：接种量为15%、温度为31 ℃、料水比为1.0:1.0发酵时间为120 h，3个菌株的接种比例为：解淀粉芽孢杆菌：植物乳杆菌：酿酒酵母=9:3:2。经微生物发酵后，发酵产物中小肽、粗蛋白质、粗灰分、粗脂肪含量较发酵前均得到显著提高（P0.05）。综上所述，豆粕经微生物固态发酵后营养价值在一定程度上得到改善，大分子蛋白质被降解，pH也发生了变化，并且单菌发酵和混菌发酵的效果存在差异。
Subjects: Biology >> Zoology submitted time 2017-10-11 Cooperative journals: 《动物营养学报》
Abstract： Various resting-state fMRI (R-fMRI) measures have been developed to characterize intrinsic brain activity. While each of these measures has gained a growing presence in the literature, questions remain regarding the common and unique aspects these indices capture. The present work provided a comprehensive examination of inter-individual variation and intra-individual temporal variation for commonly used measures, including fractional amplitude of low frequency fluctuations, regional homogeneity, voxel-mirrored homotopic connectivity, network centrality and global signal correlation. Regardless of whether examining intra-individual or inter-individual variation, we found that these definitionally distinct R-fMRI indices tend to exhibit a relatively high degree of covariation. When taken as a measure of intrinsic brain function, inter-individual differences in concordance for R-fMRI indices appeared to be stable, and negatively related to age (i.e., functional concordance among indices decreases with age). To understand the functional significance of concordance, we noted that higher concordance was generally associated with higher strengths of R-fMRI indices, regardless of whether looking through the lens of inter-individual (i.e., high vs. low concordance participants) or intra-individual (i.e., high vs. low concordance states identified via temporal dynamic analyses) differences. Finally, temporal dynamics analyses also revealed that high concordance states are characterized by increased within- and between-network functional connectivity, suggesting more general variations in network integration and segregation. The current study draws attention to questions regarding how to select an R-fMRI index for usage in a given study, as well as how to compare findings across studies that examine inter-individual or group differences using different indices. Additionally, our work suggests global neural signals exist in the brain, and their spontaneous variations over time result in fluctuations in the connectedness of brain regions.
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