Hailemariam Samson, Zhao Shengguo, Wang Jiaqi
State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Microbiol. 2020 Aug 14;11:1826. doi: 10.3389/fmicb.2020.01826. eCollection 2020.
The unclassified lineages are abundant in high yielding multiparous cows, and their presence is positively correlated with milk yield and fat percentage and reduces methane emissions. However, it is still unclear which species are associated with the most efficient feed nutrient utilization and productivity. Here, we used integrated whole genome sequencing and matrix-assisted laser desorption/ionization mass spectrometry, coupled with phenotypic and chemotaxonomic analysis, to characterize Z6, a species in isolated from the rumen. To assess the role of Z6 in nitrogen metabolism, cells grown in different nitrogen sources were analyzed by RNA sequencing. The whole genome sequence result revealed a genome size of 3.47 Mbp with 38.9% of G + C content. A total of 2993 encoding sequences account for 98%. The genes for regulating carbohydrate (10.6%) and amino acid (9%) transport and metabolism were the most abundant. ANI (Average nucleotide identity) showed that SD-Z6 was most closely related to SD-22B (99.96%). The whole genome alignment of SD-Z6 with SD-22B showed a more than 0.34 Mb nucleotide difference. Growth of SD-Z6 occurred at a temperature 36-42°C with an optimum at 39.7°C, pH 6-8; the optimum pH was 6.9 and with 0-1% (w/v) NaCl. The maximum growth (OD 0.825 ± 0.12) and microbial crude protein (MCP) (178.2 μg/ml) were observed in cells grown in amino acid. The maximum concentration of ammonia (3.96 ± 1.2) was observed in urea containing media and 1.06 mM (26.7% of the produced) remained after 24 h incubation. Activities of urease and glutamine synthase ( < 0.01) and glutamate dehydrogenase ( < 0.05) were significantly different in nitrogen and growth phase. Glutamate synthetase ( < 0.01) was significantly different only at different growth phases. In total, 1246 differentially expressed genes (DEGs) were identified in all nitrogen. Among DEGs, 33 were related to nitrogen metabolism. Their expression correlated with nitrogen sources and the intensity of enzyme activity. This result enhances our understanding of the roles of in the efficient nitrogen utilization and on environmental protection.
未分类的菌系在高产经产奶牛中大量存在，它们的存在与产奶量和脂肪百分比呈正相关，并能减少甲烷排放。然而，仍不清楚哪些物种与最有效的饲料养分利用和生产力相关。在此，我们使用整合的全基因组测序和基质辅助激光解吸/电离质谱，结合表型和化学分类分析，对从瘤胃中分离出的Z6物种进行了表征。为了评估Z6在氮代谢中的作用，我们通过RNA测序分析了在不同氮源中生长的细胞。全基因组序列结果显示基因组大小为3.47 Mbp，G + C含量为38.9%。共有2993个编码序列，占98%。调节碳水化合物（10.6%）和氨基酸（9%）转运与代谢的基因最为丰富。ANI（平均核苷酸同一性）表明SD-Z6与SD-22B关系最为密切（99.96%）。SD-Z6与SD-22B的全基因组比对显示核苷酸差异超过0.34 Mb。SD-Z6在36-42°C的温度下生长，最适温度为39.7°C，pH值为6-8；最适pH值为6.9，NaCl浓度为0-1%（w/v）。在氨基酸中生长的细胞中观察到最大生长量（OD 0.825±0.12）和微生物粗蛋白（MCP）（178.2μg/ml）。在含尿素的培养基中观察到氨的最大浓度（3.96±1.2），孵育24小时后仍有1.06 mM（产生量的26.7%）残留。脲酶和谷氨酰胺合成酶（<0.01）以及谷氨酸脱氢酶（<0.05）的活性在氮源和生长阶段存在显著差异。谷氨酸合成酶（<0.01）仅在不同生长阶段存在显著差异。在所有氮源中总共鉴定出1246个差异表达基因（DEG）。在DEG中，33个与氮代谢相关。它们的表达与氮源和酶活性强度相关。这一结果增强了我们对其在高效氮利用和环境保护中作用的理解。
