农作物秸杆发酵剂的开发利用--低温干燥对发酵剂菌种活力和酶活力影响的研究   总被引：1，自引：0，他引：1  

王成涛  朱桂华  王亚秋 《黑龙江八一农垦大学学报》1999,11(2):73-77

通过对低温干燥前后发酵剂各组分的菌数和产酶活性比较,表明45℃干燥发酵剂时菌种存活率和酶活力较高,且干燥后保存活力降低较小.  相似文献   

Carbon structure and enzyme activities in alpine and forest ecosystems     

A. Stuart Grandy  Jason C. Neff 《Soil biology & biochemistry》2007,39(11):2701-2711

The chemical structure of soil organic matter fractions and its relationship to biological processes remains uncertain. We used pyrolysis-gas chromatography/mass spectrometry to analyze the molecular structure of light and heavy fraction C from soils in the San Juan Mountains, Colorado. The soil samples, each replicated three times, were from two elevations (alpine and low forest) within two geochemically distinct basins (igneous and sedimentary). We also analyzed whether variation in the activity of nine enzymes that mediate soil organic matter turnover and nutrient cycling could explain differences in C structure. We found that, across basins and elevation, light fraction and heavy fraction C had distinct chemistries. The light fraction was characterized by an abundance of plant lignin biomarkers, including phenol, 2-methoxy-4-vinyl-(vinylguaiacol) and phenol, 2-methoxy-(guaiacol); in contrast heavy fraction had very little unaltered lignin but an abundance of polysaccharides, such as furfural, and proteins such as pyrrole. In alpine sites, light fraction was less abundant (4.27 versus 31.79 g kg⁻¹) and had a lower C/N ratio (17.25 versus 32.01) than in forests. The alpine sites also had higher activities of phosphatase, β-d-1,4-cellobiosidase, β-1,4-glucosidase, l-leucine aminopeptidase, and β-1,4-xylosidase. Protein abundance in the heavy fraction was correlated with peptidase, β-1,4-glucosidase, and phosphatase activities; in the light fraction, protein abundance was correlated with peptidase, xylosidase, and β-d-1,4-cellobiosidase activities. β-1,4-N-acetyl-glucosaminidase was negatively correlated with polysaccharides in the light and heavy fractions and positively correlated with lignin in the light fraction. However, there were not always significant correlations between enzymes and substrates. We suggest that this is likely because soil organic matter chemistry reflects long-term decomposition processes while enzyme dynamics fluctuate with current conditions or due to the presence of a pool of sorbed enzymes in the heavy fraction. While alpine and forest ecosystem C distribution and enzyme activities varied, substantial depletion of lignin derivatives in the heavy fraction across sites suggest that these compounds do not persist in stable soil C pools.  相似文献   

Experimental analysis of the effect of exotic and native plant species on the structure and function of soil microbial communities     

P.S Kourtev  J.G EhrenfeldM Häggblom 《Soil biology & biochemistry》2003,35(7):895-905

Invasions of exotic plant species are among the most pervasive and important threats to natural ecosystems, however, the effects of plant invasions on soil processes and the soil biota have rarely been investigated. We grew two exotic and a native under-story plant species in the same mineral soil from a non-invaded forest stand in order to test whether observed differences in the field could be experimentally produced in the greenhouse. We characterized changes in the soil microbial community structure (as indexed by PLFAs) and function (as indexed by enzyme activities and SIR), as well as changes in potential nitrogen mineralization rates. We found that the invasion of two very dissimilar exotic species into the under-story of deciduous forests in eastern North America can rapidly cause changes in most of the studied soil properties. At the end of the three-month incubation, soils under the exotic species had significantly different PLFA, enzyme and SIR profiles than both initial soils and soils where native shrubs had been grown. We also observed a significant increase in pH and nitrification rates under one of the exotic plants. Such changes in the soil are potentially long-term (e.g. changes in soil pH) and are therefore likely to promote the re-invasion of these and other exotics. Both management of exotic plant invasions and the restoration of native communities must take into account exotic species effects on the soil.  相似文献   

Dose-dependent sub-chronic toxicity of diethyl phthalate in female Swiss mice     

Kranti Mapuskar 《Pesticide biochemistry and physiology》2007,87(2):156-163

The experiment was conducted to study the after effects of administering DEP at different doses to female Swiss mice for a period of 90 days. Group I mice were fed on normal diet and water ad libitum. Group II mice were maintained on normal diet mixed with corn oil at 8.25 mg/kg of the diet/day as oil control. Group III, IV and V mice were given diethyl phthalate dissolved in corn oil mixed with the diet at 10, 25 and 50 mg/kg of the diet/day, which is approximately equal to 1.25, 3.125 and 6.25 mg/kg body weight/day. A significant dose dependent increase was observed in serum acid phosphatase (ACP) whereas, serum and liver triglycerides levels showed a significant increase only in the high-dose treated group. Significant dose-dependent increase in serum aspartate and alanine aminotransferase (AST and ALT) and liver glycogen was observed. Serum lactate dehydrogenase (LDH) was significantly increased only in 25 and 50 ppm DEP-treated mice. Liver cholesterol was significantly increased in all the treated groups. Liver histology by light microscopy showed intracellular vacuolations in all the treated groups which was much more evident in the 25 and 50 ppm DEP-treated mice while hepatocellular degeneration and hypertrophy of the hepatocytes was evident in 50 ppm DEP-treated mice. Proliferation of mitochondria and peroxisomes was evident in the electron micrographs of the 10 ppm DEP-treated mice while 25 and 50 ppm DEP-treated mice showed increase in lipid droplets and severe mitochondrial proliferation.  相似文献   

不同脱胶菌株胞外酶系研究   总被引：1，自引：0，他引：1  

张运雄  刘正初 《中国麻业科学》2001,23(2):27-30

运用SDS—PAGE法，通过系统研究T85—260、T1163、T66等3株脱胶菌株在纯培养、灭菌和未灭菌苎麻脱胶过程中的胞外酶系，初步明确了T85—260的胞外酶为组成型，而其它两种菌株的胞外酶为诱导型，T85—260存在较多种类脱胶关键酶，表达量多，而其它两种菌脱胶关键酶种类和表达量都少。T85—260的快速脱胶机理也作了分析。  相似文献   

Biochemical attributes of tea flowers (Camellia sinensis) at different developmental stages in the Kangra region of India     

Robin Joshi  PoonamAshu Gulati 《Scientia Horticulturae》2011

Physiological and biochemical attributes were studied in different developmental stages from unopened bud (stage 1) to full bloom (stage 5) of flowers of tea (Camellia sinensis). The proteins recorded higher levels in stages 1 and 2 and decreased thereafter with development of flowers. Like the tea shoots, flavan-3-ol EGCG and EC were present in highest and lowest amounts, respectively in all stages of flower development. The highest content of flavan-3-ols EGC and EGCG were found in stage 3. The highest proanthocyanidins content was observed in stage 2 and decreased to a minimum at full bloom stage. Polyphenol oxidase, β-glucosidase activities were found to increase from bud to stage 3 where petals started to split and slightly decreased thereafter. Glycosidic bound volatile compounds viz. Linalool oxide cis (3.11%), linalool (22.73%), geraniol (2.69%), 2,4-di-tert-butylphenol (9.71%), methyl palmitate (2.78%), methyl linoleate (2.74%), methyl salicylate (2.62%), α-terpineol (0.33), beta-ionone (1.24%) and nerolidol (0.8%) were present in higher amounts at stage 3 of flower development. The volatile flavour components recorded higher values at stage 3 of flower development with higher contents of linalool, geraniol, linalool oxides, acetophenone, pentadienal, benzaldehyde and hexanoic acid. Antioxidant activity of tea flowers also increased from bud to reach the maximum at stage 3 and decreased to a minimum in the full bloom stage.  相似文献   

藁城8901和山农1391淀粉合成酶活性和淀粉组分积累特征的比较   总被引：16，自引：4，他引：16  

刘霞  姜春明  郑泽荣  周筑南  贺明荣  王振林 《中国农业科学》2005,38(5):897-903

 选用藁城8901（强筋）和山农1391（弱筋）两个小麦品种，比较研究了其小麦蔗糖代谢、淀粉合成相关酶活性的变化及淀粉组分的积累特征。结果表明，蔗糖合成酶（SS）、磷酸蔗糖合成酶（SPS）、腺苷二磷酸葡萄糖焦磷酸化酶（ADPGPPase）、可溶性淀粉合成酶（SSS）活性以及蔗糖积累量的高低均存在明显的基因型差异，淀粉积累量较高的弱筋品种山农1391显著高于淀粉积累量较低的强筋品种藁城8901。而结合态淀粉合成酶（GBSS）活性与两品种籽粒直链淀粉积累量的变化情况相吻合，小麦籽粒灌浆中后期的GBSS活性对直链淀粉终积累量的调节作用大于籽粒灌浆前期。用Richards方程模拟籽粒直链淀粉和支链淀粉的积累过程发现，直链淀粉和支链淀粉终积累量的高低取决于其积累启动时间的早晚和前期积累速率的高低，而不是积累持续期的长短。通过比较两品种蔗糖转化量、淀粉积累速率与蔗糖和淀粉代谢相关酶活性的变化趋势可以看出，蔗糖转化量与SSS和GBSS的变化趋势一致；淀粉积累速率与ADPGPPase活性和SS/SPS活性比率的变化趋势一致，而与SS 、SPS、SSS或GBSS活性的变化并不吻合，说明籽粒中淀粉积累速率及其组分积累量的高低与SS、SPS、SSS和GBSS单个酶活性的高低并不存在必然联系，而与ADPGPPase活性和籽粒中蔗糖合成与降解的平衡密切相关。  相似文献   

Activities of the Enzymes Involved in Starch Synthesis and Starch Accumulation in the Grains of Wheat Cultivars, GC8901 and SN1391     

LIU Xia  JIANG Chun-ming  ZHENG Ze-rong  ZHOU Zhu-nan  HE Ming-rong  WANG Zhen-lin 《中国农业科学(英文版)》2005,4(5)

Two wheat cultivars, GC8901 (hard winter wheat) and SN1391 (soft winter wheat), were used for investigating the changes of enzyme activities for sucrose metabolism and starch biosynthesis and the accumulation character of starch composition.The result showed that activities of sucrose (SS), sucrose-phosphate synthase (SPS), adenosine diphosphorate glucose pyrophrylase (AGPase) and soluble starch syntheses (SSS) of 1391, which have more starch, were significant higher than those of 8901, that with low starch content. But the changing of granule-bound starch synthase (GBSS) activity was consistent with the amylose content, which indicated that amylose contents in grain were determined by GBSS activity,especially the activity at later grain filling stages. Simulating with Richards equation showed that it was initiating time and accumulation rate, but not accumulation duration that determined the content of starch composition. Furthermore, changing of sucrose transport capacity was consistent with SSS and GBSS activities, starch accumulation rate was accordant to AGPase and SS/SPS ration, not SS, SPS, SSS or GBSS activities. The results suggested that there was no inevitable relation of starch accumulating rate and starch composition contents with the activity of single enzyme such as SS, SPS,SSS or GBSS, but closely related to AGPase activity and SS/SPS ratio, and it was SPS and AGPase that play a vital role in the biosynthetic pathway. Later polymerization reactions catalyzed by SSS and GBSS don't seem to control the rate of starch accumulation, but do affect starch structure.  相似文献   

Use of electronic nose technology to measure soil microbial activity through biogenic volatile organic compounds and gases release     

Fabrizio De Cesare  Elena Di Mattia  Emiliano Zampetti  Francesco Canganella 《Soil biology & biochemistry》2011,43(10):2094-2107

Gas and volatile organic compounds (VOCs) release in soil is known to be linked to microbial activity and can differently affect the life of organisms in soil. Electronic noses (E-noses) are sensing devices composed of sensor arrays able to measure and monitor gases and VOCs in air. This is the first report on the use of such a sensing device to measure specifically microbial activity in soil. In the present study, γ-irradiated sterilised soil was inoculated with Pseudomonas fluorescens. To be sure for a rapid microbial growth and activity, two pulses of nutrient solution with organic and inorganic C, N, P and S sources were added to soil and the resulting microcosms were incubated for 23 d. During the incubation, respiration and enzyme activities of acid phosphatase, β-glucosidase, fluorescein diacetate hydrolase and protease, were measured, and microbial growth as global biomass of vital cells based on substrate-induced respiration (SIR-C_mic) and enumeration of viable and culturable cells by means of dilution plate counts (CFU) were also monitored. Concurrently, VOCs and/or gas evolution in the headspace of the soil microcosms were measured through the E-nose, upon their adsorption on quartz crystal microbalances (QCMs) comprising the sensory device. The E-nose typically generated an odorant image (olfactory fingerprint) representative of the analysed samples (soils) and resulting from the concurrent perception of all or most of the analytes in headspace, as it commonly happens when several selective but not specific sensors are used together (array). The basic hypothesis of this study was that different soil ecosystems expressing distinct microbial metabolic activities, tested through respiration and enzyme activities, might generate different olfactory fingerprints in headspace. Furthermore, the possibility to detect several substances at the same time, released from the soil ecosystems, possibly deriving from both abiotic and biotic (microbial metabolism) processes provides an “odorant image” representative of the whole ecosystem under study. The E-nose here used succeeded in discriminating between inoculated and non-inoculated ecosystems and in distinguishing different metabolic and growth phases of the inoculated bacteria during incubation. Specifically, E-nose responses were proved highly and significantly correlated with all hydrolytic activities linked to the mobilisation of nutrients from soil organic matter and their cycling, with CO₂ fluxes (respiration and presumed heterotrophic fixation) and with P. fluorescens population dynamics during exponential, stationary and starvation phases measured by SIR-C_mic and CFUs. Interestingly, the E-nose successfully detected soil microbial activity stimulated by nutrient supply, even though none of the catalytic activities tested directly produced VOCs and/or gases. The E-nose technology was then proved able to supply a real holistic image of microbial activity in the entire gnotobiotic and axenic soil ecosystems.  相似文献   

小麦胚乳淀粉合成酶基因研究进展   总被引：1，自引：0，他引：1  

余春梅陈佩度  季本华 《麦类作物学报》2004,24(4):123-128

很多研究表明。小麦胚乳淀粉的合成至少需要四类酶——腺苷二磷酸葡萄糖焦磷酸化酶、淀粉合成酶、淀粉分支酶和淀粉去分支酶，这四类酶的基因克隆和特性的研究有重要进展。目前，已从六倍体小麦发育胚乳的eDNA文库中获得AGPase两个亚基、gbssⅠ、ssⅠ、ssⅡ、ssⅢ、sheⅠ、sbeⅡ和sul(dbe)等基因的cDNA；从六倍体小麦的D组供体Triticum tauschii基因组文库中获得ssⅠ、ssⅠ、ssⅢ、sbeⅠ和sbeⅡ的gDNAs；从六倍体中只获得野生型和突变型的gbssⅠ(wx)基因。除编码AGPase大亚基的基因和sul基因未进行定位外，ssⅢ位于第一群染色体上，sheⅡ位于2DL上，其余基因均位于第七群染色体上。  相似文献