Antioxidant Activities of Hydroalcoholic Extract of <Emphasis Type="Italic">Ocimum sanctum</Emphasis> Against Cadmium Induced Toxicity in Rats

The present study was undertaken to analyze the antioxidant (both enzymic and nonenzymic) activities of leaves of Ocimum sanctum hydroalcoholic extract against cadmium induced damage in albino rats. Oral administration of cadmium as CdCl₂ (6.0 mg/kg body weight) led to significant elevation of lipid peroxidation (LPO) levels and significantly decreased Superoxide Dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPx), Reduced Glutathione (GSH) and Vitamin C (Ascorbate) levels. Administration of Ocimum sanctum extract (100 mg/kg body weight, po) and (200 mg/kg body weight, po) before and after cadmium intoxication showed a significant decrease in LPO levels and significant increase in SOD, CAT, GPx, GSH and Ascorbate levels. The results suggest that oral administration of Ocimum sanctum extract provides significant protection against cadmium induced toxicity in Wistar albino rats.     

Protective Effect of Emblica officinalis Against Alcohol-Induced Hepatic Injury by Ameliorating Oxidative Stress in Rats

The effect of Emblica officinalis fruit extract (EFE) against alcohol-induced hepatic damage in rats was investigated in the present study. In vitro studies showed that EFE possesses antioxidant as well nitric oxide (NO) scavenging activity. In vivo administration of alcohol (5 g/kg b.wt/day) for 60 days resulted increased liver lipid peroxidation, protein carbonyls, nitrite plus nitrate levels. Alcohol administration also significantly lowers the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and reduced glutathione as compared with control rats. Administration of EFE (250 mg/kg body weight) to alcoholic rats significantly brought the plasma enzymes towards near normal level and also significantly reduced the levels of lipid peroxidation, protein carbonyls and restored the enzymic and non-enzymatic antioxidants level. This observation was supplemented by histopathological examination in liver. Our data indicate that the tannoid, flavonoid and NO scavenging compounds present in EFE may offer protection against free radical mediated oxidative stress in rat hepatocytes of animals with alcohol-induced liver injury.     

纳米酶：结合天然酶和人工催化的力量

纳米酶代表了一类新型人工酶和生物催化剂,打破了无机与有机生命的界限。它既有纳米材料的理化特性,也有独特的类酶催化活性。同时,这些理化特性有可能会调控催化活性,使得纳米酶跟天然酶、传统的模拟酶和化学催化剂区别开来。纳米酶有比较好的稳定性、耐高温、低温、耐酸碱、活性可调且多功能,目前受到了广泛关注,在生物医药、环境治理、绿色农业、新能源等领域展现出巨大的应用前景,并初步形成了相应的学科框架。为了更好地推动纳米酶的发展,拓展对纳米酶的认识,文章回顾了纳米酶发现,分析凝练了纳米酶的学科特点及其结构,综述了纳米酶的应用,并展望了未来的发展趋势。     

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     

Cd胁迫对水稻根际和非根际土壤酶活性的影响研究

通过根袋法盆栽实验,研究了重金属Cd胁迫对水稻根际和非根际土壤酶活性的影响。结果表明,随着Cd浓度的增加,根际和非根际土壤呼吸强度增加,但增幅变小,根际呼吸强度大于非根际且差异显著。在梯度浓度的Cd胁迫下,根际和非根际脲酶、蔗糖酶活性随Cd浓度增加均表现出先升后降的趋势;5mg kg-1施Cd处理,根际和非根际的脲酶、蔗糖酶活性最强,在Cd浓度为30mg kg-1时,根际和非根际土壤中蔗糖酶、过氧化氢酶、非根际脲酶活性受到抑制,但抑制率各不相同;三种酶在根际土壤中的活性普遍高于非根际土壤;土壤酶对Cd污染的敏感度依次为蔗糖酶＞脲酶＞过氧化氢酶,蔗糖酶、脲酶可作检测土壤Cd污染的指示酶。低浓度Cd刺激使根系更加活力旺盛,根系形态指标对Cd胁迫敏感顺序为：根尖数＞根体积＞根表面积＞根长＞平均直径。     

递增负荷运动引起运动性血红蛋白低下的特点及机制

目的:为探讨运动性血红蛋白低下时机体铁代谢、红细胞破坏与血红蛋白下降间的关系,为运动性血红蛋白低下的发生机制及预防提供依据。方法:随机选取广州体育学院体育教育系学生30人,男女各15人,进行起始负荷为60%最大心率强度,每周强度递增10%的跑步运动,5d/周,4周后测试受试者Hb、Ret、SF、Fer、sTfR和红细胞抗氧化指标MDA、SOD、CAT、GSH-px。结果:4周递增负荷跑步运动后受试者呈现运动性血红蛋白低下,血清铁蛋白持续性下降,转铁蛋白受体呈下降趋势或不变,但血清铁无明显变化;红细胞抗氧化酶的含量升高,脂质过氧化产物MDA呈持续增加趋势。结论:4周的递增负荷跑步运动中,红细胞自由基的生成增加及红细胞抗氧化能力的相对降低引起的红细胞破坏增加可能是运动性血红蛋白低下的发生原因,而不是由单纯缺铁所致。     

相对运动强度与绝对运动强度对血清酶活性的影响

目的探讨相对运动强度和绝对运动强度对血清酶活性变化的影响。实验方法受试者为急性心肌梗塞康复病人(PMIP)和正常人(HS) ,实验前后测定了他们血清乳酸脱氢酶(L DH)、乳酸脱氢酶同工酶1(L DH- 1)、肌酸激酶(CK)、肌酸激酶亚单位MB(CK- MB)活性。结果两组受试者运动前酶的活性均无显著差异(P>0 .0 5 ) ;实验中,PMIP与HS的相对强度分别为最大心率的85 .1%、86 .0 % (P>0 .0 5 ) ,绝对强度分别为跑台等级的5 .3与6 .3(P<0 .0 5 ) ,PMIP与HS运动后即刻酶活性与运动前相比均有显著上升(P<0 .0 5 ) ,但两组间无显著差异(P>0 .0 5 ) ,2 4 h后HS组的酶活性基本恢复到运动前水平,但PMIP组仍高于运动前水平。结论运动后酶活性上升的幅度与运动所达到的相对强度有关;强度达85 % HRmax的运动能引起血清酶活性的升高,但此时L DH- 1/L DH和CK- MB/CK的比值与运动前相比无明显变化;如果PMIP的康复运动量等同于测试中的运动量,他们第2天似应停止活动以便能够得到充分的恢复。     

核糖对大强度耐力训练大鼠血清酶活性和血清尿素、血糖、肌肝糖原含量的影响

目的：探讨核糖对大强度耐力训练大鼠血清生化指标影响的机理．为核糖作为运动补剂提供试验依据。方法：选取24只大鼠．随机分为安静组、训练组和核糖加药组，训练组与训练加药组参照洪平等的训练模型进行3周的训练，最后一次训练进行一次性力竭运动，力竭后取血并进行样本处理。内容：利用ACE全自动生化分析仪，通过测定与运动训练相关的血清酶，血清尿素（BU）、血糖（Glu）浓度和肌肝糖原含量，研究了核糖对重要脏器的保护作用以及对糖、蛋白质代谢、大鼠跑台至力竭时间的影响。结论：核糖可保护重要器官免受运动的损伤；可促进运动中糖异生作用．有利于维持运动过程中血糖水平的稳定：可明显延缓大鼠运动疲劳的发生，使大鼠运动能力明显提高。     

Isolation and physiological characteristics of a premature senescence mutant in rice(Oryza sativa L.)

INTRODUCTION Leaf senescence is a kind of programmed cell death (PCD) in plants that is highly controlled by a genetically programmed process involving degrada-tion of cellular structures, decline of photosynthesis massive generation of active oxygen species (AOS) and mobilization of nutrients (Nam, 1997; Lim et al.,2003). Many environmental factors have been shown to play a role in causing the photosynthetic decline to lead to premature senescence. Leaves exposed to ultraviolet radia…     

Isolation and physiological characteristics of a premature senescence mutant in rice （Oryza sativa L.）

A rice pse(t) (premature senescence, tentatively) mutant line, was isolated from 4500 independent T-DNA inserted transgenic lines. The symptoms of premature senescence appeared more severely than those of the control plants (Zhonghua 11,japonica) at the last development stage. To characterize the mutant and provide basic information on the candidate genes by mapping to a physical region of 220-kb, experiments were carried out in two phytotrons under controlled temperature of 24 ℃ and28 ℃, respectively. The content of chlorophyll, soluble protein and MDA (malondialdehyde), net photosynthesis, the antioxidant enzyme activities of SOD (superoxide dismuase) (EC 1.15.1.1) and POD (peroxidase) (EC 1.11.1.7) and the peptidase activities of leaves were measured from top to bottom according to the leaf positions at the flowering stage. Compared with the control plant,the mutant showed the following characteristics: (1) Higher net photosynthesis rate (Pn) appeared in the 1 st and 2nd leaves, contents of chlorophyll and soluble protein were also higher in the 1 st leaf; (2) The activities of SOD, POD and peptidase were higher according to the leaf position from top to bottom; (3) The symptom of premature senescence was accelerated in the mutant at 28℃treatment. The MDA content and the SOD and POD activities between the 24 ℃ and 28 ℃ treatment mutants were not significantly different. Content of chlorophyll and soluble protein of leaves mutant decreased rapidly at 28 ℃ treatment. The results show that pse(t) is sensitive to high temperature. The probable function of PSE(T) is discussed.