Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum

BackgroundLignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth.ResultsHere, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance.ConclusionsThe microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries.How to cite: Bai D, Lin X, Hu Y, et al. Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum. Electron J Biotechnol 2021;50. https://doi.org/10.1016/j.ejbt.2020.12.001     

Association of p53 codon 72 polymorphism with liver metastases of colorectal cancers positive for p53 overexpression

Objective: To evaluate the association between p53 codon 72 polymorphism (R72P) and the risk of colorectal liver metastases. Methods: The p53 R72P genotype was identified by polymerase chain reaction-restriction fi'agment length poly-morphism (PCR-RFLP) method in 78 consecutive colorectal cancer patients with liver metastases and 214 age- and sex-matched cases with nonmetastatic colorectai cancer. Results: The R allele of the p53 R72P polymorphism was more frequently found in metastatic cases than in nonmetastatic cases (P=0.075). Carriers of the 72R allele had a 2.25-fold (95% CI (confidence inter-val)=1.05～4.83) increased risk of liver metastases. On the stratification analysis, 72R-carrying genotype conferred a 3.46-fold (95% CI=1.02～11.72) and a 1.05-fold (95% CI=0.36～3.08) increased risk of liver metastases for p53 overexpression-positive and negative colorectal cancers, respectively. Conclusion: These results demonstrate for the first time that the 72R allele of the p53 polymorphism has an increased risk for liver metastases in colorectal cancers positive for p53 overexpression.     

耐力训练对大鼠肝脏、股四头肌中谷胱甘肽含量的影响

谷胱甘肽对清除机体内自由基有重要作用。本文通过检测大鼠肝脏、股四头肌中谷胱甘肽──还原型谷胱甘肽（ＧＳＨ）、氧化型谷胱甘肽（ＧＳＳＧ）的含量及脂质过氧化产物丙二醛（ＭＤＡ）的含量，观察运动、训练后大鼠肝脏、股四头肌中谷胱甘肽含量的变化，研究耐力训练对谷肌甘肽在消除运动时内源性自由基的影响。实验结果显示大鼠经１１周跑台训练后，安静状态时肝脏中ＭＤＡ含量下降、ＧＳＨ含量增加，而股四头肌中ＭＤＡ、ＧＳＨ含量均不变；９０分钟定量负荷运动后，训练组大鼠表现了良好的运动适应，肝脏、股四头肌中具有较高的ＧＳＨ含量，ＧＳＨ／ＧＳＳＧ比值也较高，ＭＤＡ含量也较对照组增加少，且恢复较快。另外发现耐力训练引起大鼠肝脏、股四头肌中ＭＤＡ、谷胱甘肽含量的变化不完全一致。     

虫源壳聚糖对大鼠运动能力及骨骼肌抗氧化酶系的影响

目的:探讨补充不同浓度虫源壳聚糖对大鼠运动能力和骨骼肌抗氧化酶系的影响。方法:对大负荷游泳训练大鼠补充剂量分别为各组平均体重的0.5 g.kg-1、1.0 g.kg-1和2.0 g.kg-1的虫源壳聚糖,在8周大负荷训练结束后测定力竭游泳时间和骨骼肌抗氧化酶系的活性。结果:8周大负荷训练后,虫源壳聚糖大负荷运动组力竭游泳时间均明显长于单纯大负荷运动组,补充2.0 g.kg-1虫源壳聚糖组游泳力竭时间比单纯大负荷运动组延长了25.56%。补充虫源壳聚糖能够显著提高抗氧化酶系活性,虫源壳聚糖0.5 g.kg-1补充组与单纯大负荷运动组相比,CAT和GST酶活性显著升高(P<0.05),但SOD活性无显著差异;虫源壳聚糖1.0 g.kg-1和2.0 g.kg-1补充组与单纯大负荷运动组相比:SOD酶活性显著提高(P<0.05),CAT和GST酶活性升高极为显著(P<0.01)。MDA含量在不同水平虫源壳聚糖补充组均显著低于单纯大负荷运动组(P<0.01)。结论:补充虫源壳聚糖有助于提高训练大鼠的运动能力及骨骼肌抗氧化酶系活性。     

肝炎肝硬化并发细菌性腹膜炎的原因分析与护理对策

目的:总结和探讨肝炎肝硬化并发细菌性腹膜炎的病因、发病机制和护理对策.方法:本文通过对53例肝炎肝硬化并发细菌性腹膜炎患者的临床观察和分析.结果:本案例有9例死亡,44例康复出院.结论:针对肝炎肝硬化并发细菌性腹膜炎患者病情变化的特点,采取相应的临床护理和心理护理方法,可提高治愈率,降低死亡率.     

Thyroidal regulation of substrate kinetics properties of cytochrome oxidase in rat liver mitochondria

Effects of thyroidectomy (T_x) and subsequent treatment with 3,5,3’-triiodothyronine (T₃), and combined treatment (T_R) with T₃ + thyroxine (T₄) on substrate kinetics properties of cytochrome oxidase of rat liver mitochondria were examined. T_x resulted in lowering of cytochromes content with decrease in the enzyme activity, and K_m and V_max. T₃ and T_R regimens restored the cytochromes contents and the V_max values to normal. In control, T₃ and T_R groups the enzyme activity resolved in two kinetic components; in T_x group three kinetic components were evident. The K_m values for all components decreased significantly in the experimental groups with concomitant increase in catalytic efficiency, K_cat/K_m. Significant alterations in the contents of total phospholipid and of cholesterol were noted while the changes in the phospholipids composition were only of restricted nature. Regression analysis revealed that total phospholipid, cholesterol and phosphatidylcholine, phosphatidylethanolamine play significant role in fine tuning the enzyme activity.     

Proteomic analysis of differentially expressed proteins in mice with concanavalin A-induced hepatitis

Objective: To find new protein biomarkers for the detection and evaluation of liver injury and to analyze the relationship between such proteins and disease progression in concanavalin A (Con A)-induced hepatitis. Methods: Twenty-five mice were randomly divided into five groups: an untreated group, a control group injected with phosphate buffered saline (PBS), and groups with Con A-induced hepatitis evaluated at 1, 3 and 6 h. Two-dimensional gel elec-trophoresis (2-DE) and mass spectrometry (MS) were used to identify differences in protein expression among groups. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify the results. Results: In mice with Con A-induced hepatitis, expression levels of four proteins were increased: RIKEN, fructose bisphosphatase 1 (fbp1), ketohexokinase (khk), and Chain A of class pi glutathione S-transferase. Changes in fbp1 and khk were confirmed by qRT-PCR. Conclusion: Levels of two proteins, fbp1 and khk, are cleady up-regulated in mice with Con A-induced hepatitis.     

利用大豆内源酶改善腊八豆的品质

大豆经内源酶作用生产腊八豆,产品的氨基态氮和还原糖的含量都有增加,货架期内产品的硬度明显降低。试验表明大豆内源酶适宜作用的条件为：大豆经25℃浸后,30℃发芽处理8h,再于40℃处理6h利用内源酶降解大豆本身的部分大分子物质。大豆经此处理后生产的腊八豆与空白处理相比,氨基态氮的含量提高22.5%,产品的硬度降低37.1%。     

Vascular architecture:is it a helpful histopathological biomarker for hepatocellular carcinoma?

Hepatocellular carcinoma(HCC) remains one of the major public health problems throughout the world.Although originally associated with tumorigenic processes,liver angiogenesis has also been observed in the context of different liver in-flammatory,fibrotic,and ischemic conditions.Here we investigate the fractal dimension as a quantitator of non-Euclidean two-dimensional vascular geometry in a series of paired specimens of primary HCC and surrounding non-tumoral tissue,and discuss why this parameter might provide additional information regarding cancer behavior.The application of fractal geometry to the measurement of liver vascularity and the availability of a computer-aided quantitative method can eliminate errors in visual interpretation,and make it possible to obtain closer-to-reality numerals that are compulsory for any measurement process.     

Review and Recommendations for the Component Tests in the Liver Function Test Profile

Pathology laboratories group some tests that they perform on their high throughput biochemistry analysers into profiles of tests that are associated with different organs (e.g. liver function tests—LFT). The components of these profiles are historic and often vary between different laboratories. This can lead to confusion and begs the question of what should be in a particular profile. In community medicine profiles may be used as screening tests but some of the components of the profiles may have low sensitivity and specificity and may produce both false positives and negatives. The LFT may include components which are poor liver function tests but are sensitive to fatty liver and hence elevations may cause unnecessary concern. Harmonisation of clinical chemistry reference intervals and units is occurring now so it is time to consider a similar process for components of a profile. A proposed list of analytes to be performed in the LFT profile is given.