化感水稻根际微生物类群及酶活性变化

以化感水稻PI312777（PI）和非化感水稻Lemont（LE）为材料,分别测定不同水稻叶龄期（3～7叶期）根际微生物区系变化及根际土壤酶活性.结果表明,化感水稻明显影响土壤根际微生物类群及相关酶活性.化感水稻PI根际细菌、放线菌、固氮菌的数量高于非化感水稻LE,增幅分别在11.2%～28.3%、40%～78.6%和111.5%～173.9%之间,而真菌数量低于非化感水稻LE,最高仅为其值的25.5％,说明化感水稻PI对绝大多数细菌、放线菌、固氮菌生长有促进作用,对一些真菌生长有抑制作用.进一步分析表明,化感水稻PI对氨化细菌、亚硝酸细菌、硝酸细菌、好气性固氮菌、好气性纤维素分解菌、硫化细菌的生长具有促进作用,其中以氨化细菌、好气性固氮菌的更为明显,最低增幅分别为53.7％和57.6％;而对反硫化细菌、反硝化细菌生长有抑制作用,其值最高分别为非化感水稻的54.2％和50.6％.此外,化感水稻PI根系分泌物对脲酶、磷酸酶、蔗糖酶的活性具有促进作用,而对过氧化氢酶则呈抑制作用.     

Changes in the proteolytic activity of tissues during aging

The intensity of proteolytic processes and qualitative composition of autolysis products of the brain, liver and testicle tissues of young and old rats were studied. The gel-chromatographic analysis (Sephadex G-15 and G-50) revealed no considerable amount of high-molecular peptides (1500 Da and over) before and after autolysis. The measurement of the quantity of free amino groups in the gel-chromatographic fraction after the complete acid hydrolysis has confirmed that result. The low-molecular peptides and free amino acids, are the main products of the tissue autolysis. The intensity of proteolytic processes, determined by an increase in the amount of amino acids depends on the autolysis duration and age of animals. The total increment of amino acids in the brain and liver tissues of old animals for the first hour of autolysis has been higher by 102 and 219% as compared to young ones. The autolysis of testicles of the young and old animals after the first hour of incubation is characterized by the same intensivity. Such a regularity is not revealed when analyzing the same processes by the Lowry method.     

Impaired hormonal regulation of enzyme activity during aging.

A general feature of all aging populations is the progressively impaired ability to adapt to changes in the surrounding environment. Biochemical expressions of adaptive response include modifications in the rates of enzyme synthesis and degradation, as well as alterations in physiological activity. Therefore, the effects of aging on enzyme adaptation were surveyed in an attempt to explore fundamental biochemical mechanisms in the deterioration of responsiveness. The ability to stimulate adaptive increases in the activity of a large number of enzymes is impared during aging in a variety of tissues from several different species. The impaired capability for liver enzyme adaptation in a rigorously controlled colony of aging male Sprague-Dawley rats probably reflects alterations in hormonal control mechanisms. The present article reviews and evaluates our interest in understanding the effects of aging on regulation of liver enzyme activity by the hormones, insulin and corticosterone. Specific areas currently under investigation include: (1) the regulation of their concentrations in blood; (2) the integrity of their receptor systems in liver; and (3) effectiveness of the endogenous hormone pools fromthe viewpoints fothe availability of physiological antagonists and the potential for alterations in molecular structure.     

传统发酵肉制品中微生物菌群对风味形成的研究进展

我国传统发酵肉制品种类丰富、风味独特。本文主要介绍参与肉制品发酵的微生物,从蛋白质、脂质和碳水化合物代谢途径的角度概述微生物对发酵肉制品呈香物质形成的作用机制,以及发酵过程中微生物的演替与风味变化的关系。     

Changes in antioxidant enzyme activities, fatty acid composition and lipid peroxidation in Daphnia magna during the aging process

Age-related changes in the balance between endogenous pro-oxidative and antioxidative processes in the freshwater cladoceran Daphnia magna (Crustacea) were assessed. The activities of key antioxidant enzymes including catalase, superoxide dismutase and glutathione peroxidase and levels of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) were determined in eight age classes, covering juvenile, young and senescent adults. Age-related changes in fatty acid composition were also measured to examine the contribution of polyunsaturated fatty acids (PUFA) in the peroxidation status of animals. Biochemical responses depicted in this study demonstrated that age-related decline in survival was accompanied by increasing oxidative stress and oxidative damage. Enhanced oxidative stress in aging D. magna was suggested by the significant increase in the formation of lipid peroxides, and a concomitant reduction of unsaturated fatty acids of 20 or more carbon atoms. Because aging was accompanied by selective loss of key antioxidant enzymes and small changes in the amount of PUFA, the breakdown of antioxidant defences might have directly contributed to oxidative stress, membrane lipid peroxide and a decline of survival. Indeed, the results reported here, indicate that age-related increases of lipid peroxides were at least partially due to the functional imbalance of enzymatic antioxidant defences.     

Changes in prostacyclin and thromboxane biosynthesis and their catabolic enzyme activity in kidneys of aging rats

The effects of aging on the prostacyclin and thromboxane biosynthesis and prostaglandin catabolic enzyme activity in rat kidney were investigated. The prostacyclin biosynthesis, using arachidonic acid as substrate, was the greatest in young kidneys (2 months old) and then progressively decreased in mature (12 months old) and old (24 months old) kidneys, while thromboxane biosynthetic activity showed no significant change as a function of age. When prostaglandin H2 was used as substrate, the prostacyclin and thromboxane biosynthesis showed similar results as when arachidonic acid was used as substrate; the prostacyclin biosynthesis progressively decreased and thromboxane biosynthesis showed no significant change as a function of age. The fatty acid cyclooxygenase in kidney was measured by a specific radioimmunoassay. No significant change in renal fatty acid cyclooxygenase as a function of age was found. Thus, we concluded that the progressive decrease in renal prostacyclin biosynthesis as a function of age is due to a defect in prostacyclin synthetase in aged kidneys. The prostaglandin catabolic enzyme, NAD+-dependent 15-hydroxyprostaglandin dehydrogenase, in kidneys was also investigated. The enzyme activity progressively decreased as a function of age, which suggested a decrease in the metabolism of thromboxane A2 in aged kidneys. The present results, indicating a decrease in renal prostacyclin biosynthesis and renal 15-hydroxyprostaglandin dehydrogenase activity with aging, might contribute to a plausible explanation of the progressive decrease in renal functions in the elderly.     

Changes in enzyme binding and activity during aestivation in the frog Neobatrachus pelobatoides

1. The proportion of aldolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) associated with the particulate fraction of a cell was measured in aestivating and non-aestivating Neobatrachus pelobatoides. 2. Reduced binding of these enzymes was found in the brain, indicating lower glycolytic flux. This was not correlated to metabolic rate suggesting that glycolytic rate was reduced in this tissue in the early stages of aestivation, possibly due to a change in fuel use. 3. Measurement of total enzyme levels showed that the liver of aestivating frogs had less GAPDH and less aldolase than non-aestivating frogs.     

Changes in enzyme activity and isoperoxidases in haploid tobacco callus during organogenesis

Haploid tobacco tissues cultured on Murashige and Skoog (MS) medium supplemented with 0.3 mg/l indole-3-acetic acid (IAA) and 1% sucrose remained undifferentiated. Increasing sucrose level (3%) at the same IAA concentration induced shoot differentiation in 9 days. Further increase in sucrose level (6%) resulted in root differentiation on day 12. Total specific activity of peroxidase, IAA oxidase, malate dehydrogenase (MDH) and phenylalanine ammonia-lyase (PAL) exhibited definite development variations among the three programmes. The number of the anodic and cathodic isoperoxidase bands changed in each case with time. Shoot formation was characterized by the synthesis of anodic peroxidases: AS₁ (Rm=0.41), AS₂ (Rm=0.44) and AS₃ (Rm=0.46), all three being synthesized prior to visual manifestation of shoots. Likewise, root differentiation was heralded in advance by synthesis of one anodic isoperoxidase AR (Rm=0.30). Cathodic isoperoxidases did not show any subtle correlation with shoot or root formation.     

Changes in enzyme activity during differentiation in Chlamydomonas reinhardtii

The patterns of alanine dehydrogenase, glutamate dehydrogenase and malate dehydrogenase activity were studied during the normal vegetative cell cycle and during the process of gametic differentiation and dedifferentiation in synchronized cultures of Chlamydomonas reinhardtii. During all three phases of growth and differentiation the synthesis of DNA was also measured. During gametic differentiation all three enzyme levels were suppressed compared to vegetative cells although DNA and cell number were comparable. During gametic dedifferentiation no DNA synthesis occurred during the first 24 h cycle and only a doubling during the second. It was not until the third cycle that a normal 4-fold increase in DNA was observed. Cell number followed a similar pattern. Athough the levels of alanine dehydrogenase and malate dehydrogenase were uniformly low during the first cycle when glutamate dehydrogenase increased 4-fold, during the second cycle the patterns of these enzymes changed markedly. The enzymes did not attain levels characteristic of vegetative cells until the third cycle.     

Volatile compounds of Soumbala, a fermented African locust bean (Parkia biglobosa) food condiment

AIMS: To determine the profile of volatile compounds responsible for the aroma of Soumbala produced spontaneously and with pure and mixed cultures of Bacillus subtilis and Bacillus pumilus. METHODS AND RESULTS: Traditional and controlled fermentation trials of African locust bean with pure and mixed starter cultures of B. subtilis (B7, B9 and B15) and B. pumilus (B10) were performed. Aroma volatiles were analysed using Likens-Nikerson method coupled with gas chromatography and mass spectrophotometry. Sensory analysis of Soumbala as well as rice dishes prepared with each type of Soumbala were carried out by 10 panellists. In total 116 compounds were identified. They included pyrazines, aldehydes, ketones, esters, alcohols, acids, alkanes, alkenes, amines, pyridines, benzenes, phenols, sulphurs, furans and other compounds. Using principal component analysis for comparison, the aroma profiles of the Soumbala samples could be separated into three groups. The sensory evaluation showed variable acceptability. However, it was noticed that Soumbala samples produced with starter cultures were scored higher than traditionally prepared Soumbala. CONCLUSIONS: Aroma volatiles and organoleptic properties of Soumbala vary according to the Bacillus isolates involved in the fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to the selection of Bacillus starter cultures for controlled production of Soumbala.     

Changes in enzyme activity of glycogen and hexose metabolism during oocyte maturation in a teleost,Misgurnus fossilis L.

Summary The oocyte at the end of oogenesis, mature egg and developing embryo of the loachMisgurnus fossilis L.) are characterized by indentical enzyme profiles of the Embden-Meyerhof chain, pentose phosphate cycle and key gluconeogenic enzymes. However, the carbohydrate metabolism in the oocyte differs substantially from that in the embryo.Oocyte maturation is followed by a complete loss of hexokinase (EC2.7.1.1),2-fold decrease of glycogen synthetase (EC 2.4.1.11) and 10-fold increase of glycogen phosphorylase (EC2.4.1.1) activity. This process is correlated with a gradual decrease of the ATP/(ADP+AMP) ratio from 41 to 21 and increase of the Fructose-6-Phosphate/Fructose-1,6-Diphosphate ratio from 0.27 to 2.0. Thus, oocyte maturation involves a number of changes in control mechanisms resulting in cessation of glycogen accumulation and a transition of carbohydrate metabolism from gluconeogenesis to glycogenolysis.

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Zusammenfassung Die Oozyte und das reife Ei vonMisgurnus fossilis L. besitzen die gleiche Enzymzusammensetzung der Embden-Meyerhof Wege, unterscheiden sich aber wesentlich in den Enzymen des Metabolismus des Glykogens und der Hexosemonophosphate. Beim Reifen der Oozyte erfolgt eine 10fache Zunahme der Aktivität der Phosphorylase (EC 2.4.1.1.), völliger Verlust der Hexokinase (EC 2.7.1.1.) und eine wesentliche Abnahme der Glycogensynthetase (EC 2.4.1.11).Das Verhältnis ATP/(ADP+AMP)geht von 4l auf 2-1 zurück, dasjenige von Fructose-6-Phosphat/Fructose-1,6-Diphosphat nimmt von 0,27 auf 2,0 zu.Änderungen der regulatorischen Mechanismen beim Reifen der Oozyte setzen die Geschwindigkeit der Glykogensynthese und Glukoneogenese scharf herab, unterbinden die Ausnutzung der freien Glukose bei der Glykolyse und sichert eine allmähliche Zunahme der Glykogenolyse während der frühen Entwicklung des Embryos.

     

不同发酵茶中优势真菌的抗氧化酶活性

目的在云南普洱茶、广州小青柑、广西六堡茶、湖南熙茯茶及陕西泾阳茯砖茶分离到9种真菌的基础上,探讨9种真菌发酵液和发酵茶沸水冲泡液的抗氧化酶活性。方法采用抗氧化试剂盒测定真菌发酵液及发酵茶沸水冲泡液的抗氧化酶活性;利用Past 3软件对9种真菌发酵液抗氧化酶活性和5种发酵茶沸水冲泡液的抗氧化酶活性进行主成分分析。结果通过比较不同真菌发酵液的抗氧化酶活性表明,小青柑中分离到阿曲霉Q1的CAT(过氧化氢酶)活性最高,酶活力单位为(4.37±0.15)U/mL,熙茯茶中分离到谢瓦曲霉X1的POD(过氧化物酶)活性最高,酶活力单位为(21.67±1.05)U/mL,其次为泾茯茶中分离到赤散囊菌J17,酶活力单位为(18.59±2.74)U/mL;六堡茶中分离到的黑曲霉L1的T-SOD(总超氧化物歧化酶)的活性最高,酶活力单位为(71.11±3.90)U/mL,其次为普洱茶中分离到篮状菌P1,酶活力单位为(59.29±1.42)U/mL;通过比较不同发酵茶沸水冲泡液的抗氧化酶活性表明,5种发酵茶的CAT(F=37.409,P0.01),POD(F=164.268,P0.01),T-SOD(F=26.639,P0.01)活性差异均有统计学意义。其中,泾茯茶冲泡液的CAT活性最高,而其余4种茶叶冲泡液均无CAT活性;普洱茶与泾茯茶冲泡液的POD活性最高,酶活力单位分别为(18.11±0.71)和(18.11±0.64)U/mL;普洱茶和六堡茶冲泡液的T-SOD活性最高,酶活力单位分别为(48.72±0.43)和(45.82±2.02)U/mL;通过对9种真菌发酵液抗氧化酶活性的PCA分析表明,谢瓦曲霉X1、赤散囊菌J17、阿曲霉Q1、烟曲霉Q2、绳状篮状菌Q3和冠突曲霉L2的抗氧化酶活性相近,篮状菌P1、篮状菌P2和黑曲霉L1的抗氧化酶活性相近;通过对5种发酵茶沸水冲泡液抗氧化酶活性的PCA分析表明,小青柑与熙茯茶沸水冲泡后的抗氧化酶活性相近,六堡茶、普洱茶和泾茯茶沸水冲泡后的抗氧化酶活性相近。结论不同发酵茶的优势真菌不同,其真菌发酵产物的抗氧化酶活性不同,且不同发酵茶冲泡液的抗氧化酶活性也不同。     

Changes in DNA repair during aging

DNA is a precious molecule. It encodes vital information about cellular content and function. There are only two copies of each chromosome in the cell, and once the sequence is lost no replacement is possible. The irreplaceable nature of the DNA sets it apart from other cellular molecules, and makes it a critical target for age-related deterioration. To prevent DNA damage cells have evolved elaborate DNA repair machinery. Paradoxically, DNA repair can itself be subject to age-related changes and deterioration. In this review we will discuss the changes in efficiency of mismatch repair (MMR), base excision repair (BER), nucleotide excision repair (NER) and double-strand break (DSB) repair systems during aging, and potential changes in DSB repair pathway usage that occur with age. Mutations in DNA repair genes and premature aging phenotypes they cause have been reviewed extensively elsewhere, therefore the focus of this review is on the comparison of DNA repair mechanisms in young versus old.     

Changes in mitochondrial enzyme activity of rat lung during the development of silicosis.

Significant changes occurred in the activities of enzymes in silicotic rat lung at 30, 90 and 150 days after intratracheal injection of quartz dust. The pattern of changes indicated that the mitochondrial metabolism in silicosis is altered significantly indicating disturbances in bioenergetics. Increase in activity of cytochrome-$\text{c}$-oxidase and NADH-cytochrome-$\text{c}$-reductase at the early stage and a significant decline at the advanced stage of the disease suggest that metabolic changes in silicosis during the initial and the advanced stage of the disease are distinctly different. Besides, enhanced rate of glycolysis is also observed at the early stages of silicosis.     

Changes in the microbial community during repeated anaerobic microbial dechlorination of pentachlorophenol

Pentachlorophenol (PCP) has been widely used as a pesticide in paddy fields and has imposed negative ecological effect on agricultural soil systems, which are in typically anaerobic conditions. In this study, we investigated the effect of repeated additions of PCP to paddy soil on the microbial communities under anoxic conditions. Acetate was added as the carbon source to induce and accelerate cycles of the PCP degradation. A maximum degradation rate occurred at the 11th cycle, which completely transformed 32.3 μM (8.6 mg L^?1) PCP in 5 days. Illumina high throughput sequencing of 16S rRNA gene was used to profile the diversity and abundance of microbial communities at each interval and the results showed that the phyla of Bacteroidates, Firmicutes, Proteobacteria, and Euryarchaeota had a dominant presence in the PCP-dechlorinating cultures. Methanosarcina, Syntrophobotulus, Anaeromusa, Zoogloea, Treponema, W22 (family of Cloacamonaceae), and unclassified Cloacamonales were found to be the dominant genera during PCP dechlorination with acetate. The microbial community structure became relatively stable as cycles increased. Treponema, W22, and unclassified Cloacamonales were firstly observed to be associated with PCP dechlorination in the present study. Methanosarcina that have been isolated or identified in PCP dechlorination cultures previously was apparently enriched in the PCP dechlorination cultures. Additionally, the iron-cycling bacteria Syntrophobotulus, Anaeromusa, and Zoogloea were enriched in the PCP dechlorination cultures indicated they were likely to play an important role in PCP dechlorination. These findings increase our understanding for the microbial and geochemical interactions inherent in the transformation of organic contaminants from iron rich soil, and further extend our knowledge of the PCP-transforming microbial communities in anaerobic soil conditions.     

Changes in leukocyte enzyme activity during experimental amyloidogenesis and in patients with amyloidosis]

The activity of hydrolytic and redox myeloperoxidase enzymes was determined in the neutrophils and lymphocytes of the peripheral blood of patients with secondary amyloidosis and also of the animals with amyloidogenesis and amyloidosis (caseine model). During the amyloidogenesis the activity of hyocrolytic enzymes and of myeloperoxidase in the neutrophils was found to decrease; this was particularly marked at the stage of the initial amyloid deposition. Changes in the enzyme activity in the animals against the background of already developed amyloidosis coincided with such in the blood cells of patients with secondary amyloidosis. The results obtained are discussed from the aspects of resorption theory.     

地黄连作对根际微生物区系及土壤酶活性的影响

以地黄连作2年和1年的土壤为研究对象,分别测定了根际微生物区系变化及根际土壤酶活性．结果表明：地黄连作对其根际微生物区系及土壤酶活性产生了较大的影响．随种植年限的增加,根际细菌和真菌减少,但差异均不显著;放线菌增多,连作2年的土壤约为1年的4倍．土壤中氨化细菌、好气性固氮菌、硫化细菌、反硝化细菌和嫌气性纤维素分解菌分别增加了25．99、45．39、11．43、1．36和1．43倍,而好气性纤维素分解菌减少了86．74％．连作地黄根系的分泌物对脲酶、多酚氧化酶、蔗糖酶、蛋白酶和纤维素酶活性具有促进作用,分别增加了62．87％、9．43％、47．91％、139．62％和31．33％,而对过氧化氢酶则呈抑制作用．说明地黄连作会破坏根际微生物种群平衡．