Ratio Of Enzyme Activity Research Articles

Resistance monitoring and enzyme activity in three field populations of cowpea aphid (Aphis craccivora) from Egypt

The cowpea aphid (Aphis craccivora) is one of the most important sucking insect pests attacking certain legumes in Egypt particularly faba bean, cowpea and pea. In this study we monitored the resistance level of three field populations of A. craccivora to seven insecticides belonging to three different chemical classes (organophosphates, carbamates and neonicotinoids). The three populations were collected from three governorates in Egypt namely Dakahlia, Qalyobia and Beni Suef. Diagnostic concentrations (LC90 values for susceptible strain) for each insecticide were established using a leaf dipping technique. Resistance monitoring showed that the field population from Dakahlia was highly resistant to all the tested insecticides. In a similar manner, the population from Qalyobia was also resistant to all insecticides except for fenitrothion to which only moderate resistance was observed. The field population from Beni Suef exhibited a lower level of resistance to all the seven tested insecticides.Biochemical assay showed that esterase activity in these three field populations was generally higher as the enzyme activity ratio ranged from 4.3 to 7.8 fold more than that for the susceptible strain. The activity of the other measured detoxifying enzymes (glutathione -S- transferase and mixed function oxidases) was moderate in the populations from Qalyobia and Dakahlia. Nevertheless, the enzyme activity in A. craccivora collected from Beni Suef was variable and differed slightly from the activity measured in the susceptible strain. Monitoring insecticide resistance among the three aphid populations was a proactive approach to detect any shift in insecticide efficiency. The possible occurrence of resistance in the cowpea aphid to the tested insecticides may be due to the higher activity of carboxylesterases. Further studies on the resistance mechanism to these insecticides are needed to provide insights in how to manage and delay the onset of the resistance and thus prolong the performance of insecticides against A. craccivora.

Crop rotational diversity enhances belowground communities and functions in an agroecosystem.

Biodiversity loss, an important consequence of agricultural intensification, can lead to reductions in agroecosystem functions and services. Increasing crop diversity through rotation may alleviate these negative consequences by restoring positive aboveground-belowground interactions. Positive impacts of aboveground biodiversity on belowground communities and processes have primarily been observed in natural systems. Here, we test for the effects of increased diversity in an agroecosystem, where plant diversity is increased over time through crop rotation. As crop diversity increased from one to five species, distinct soil microbial communities were related to increases in soil aggregation, organic carbon, total nitrogen, microbial activity and decreases in the carbon-to-nitrogen acquiring enzyme activity ratio. This study indicates positive biodiversity-function relationships in agroecosystems, driven by interactions between rotational and microbial diversity. By increasing the quantity, quality and chemical diversity of residues, high diversity rotations can sustain soil biological communities, with positive effects on soil organic matter and soil fertility.

Functional significance of single nucleotide polymorphisms in the lactase gene in diverse US patients and evidence for a novel lactase persistence allele at -13909 in those of European ancestry.

Recent data from mainly homogeneous European and African populations implicate a 140-bp region 5' to the transcriptional start site of LCT (the lactase gene) as a regulatory site for lactase persistence and nonpersistence. Because there are no studies of US nonhomogeneous populations, we performed genotype/phenotype analysis of the -13910 and -22018 LCT single nucleotide polymorphisms (SNPs) in New England children, mostly of European ancestry. Duodenal biopsies were processed for disaccharidase activities, RNA quantification by reverse transcription polymerase chain reaction (RT-PCR), allelic expression ratios by PCR, and genotyping and SNP analysis. Results were compared with clinical information. Lactase activity and mRNA levels, and sucrase-to-lactase ratios of enzyme activity and mRNA, showed robust correlations with genotype. None of the other LCT SNPs showed as strong a correlation with enzyme or mRNA levels as did -13910. Data were consistent, with the -13910 being the causal sequence variant instead of -22018. Four individuals heterozygous for -13910T/C had allelic expression patterns similar to individuals with -13910C/C genotypes; of these, 2 showed equal LCT expression from the 2 alleles and a novel variant (-13909C>A) associated with lactase persistence. The identification of -13910C/C genotype is likely to predict lactase nonpersistence, consistent with prior published studies. A -13910T/T genotype will frequently, but not perfectly, predict lactase persistence in this mixed European-ancestry population; a -13910T/C genotype will not predict the phenotype. A long, rare haplotype in 2 individuals with -13910T/C genotype but equal allele-specific expression contains a novel lactase persistence allele present at -13909.

Glutathione redox system, immune status, antioxidant enzymes and metabolism of purine nucleotides in hypothyroidism

The immune status, components of the glutathione redox system, the activity of antioxidant enzymes and metabolism of purine nucleotides have been investigated in animals with experimental hypothyroidism. On day 8 after an increase in the number of leukocytes, lymphocytes, T-helpers and T-suppressors as well as increased number of B-lymphocytes was found in blood of thyroidectomized rats. This was accompanied by decreased activity of adenosine deaminase (AD), AMP-deaminase (AMPD), and 5'-nucleotidase (5'N) in blood, but the ratio of enzyme activity AD/AMPD increased. These changes in the activity of enzymes, involved in purine catabolism can be regarded as increased functional relationships between T and B lymphocytes in hypothyroidism. The functional changes of immune system cells were accompanied by increased activity of glutathione peroxidase (GPx), a decrease in the activity of superoxide dismutase (SOD), glutathione reductase (GR) and the ratio GH/GPx. Thyroidectomized rats had increased amounts of total, oxidized (GSSG) and reduced glutathione (GSH), but the ratio GSH/GSSG decerased as compared with control animals. In the liver, hypothyroidism resulted in activation of SOD, GPx, decreased activity of GR and decreased ratio GR/GPx. At the same time, the levels of total, oxidized, and reduced glutathione increased, but the ratio GSH/GSSG as well as activities of enzymes involved in purine nucleotide metabolism ratio (and their ratio 5'N/AD + AMPD) decreased. All these data suggest a functional relationship of the glutathione redox system not only with antioxidant enzymes, but also activity of enzymes involved purine nucleotide metabolism and immune status.

Metabolic control analysis of the Trypanosoma cruzi peroxide detoxification pathway identifies tryparedoxin as a suitable drug target

BackgroundThe principal oxidative-stress defense in the human parasite Trypanosoma cruzi is the tryparedoxin-dependent peroxide detoxification pathway, constituted by trypanothione reductase (TryR), tryparedoxin (TXN), tryparedoxin peroxidase (TXNPx) and tryparedoxin-dependent glutathione peroxidase A (GPxA). Here, Metabolic Control Analysis (MCA) was applied to quantitatively prioritize drug target(s) within the pathway by identifying its flux-controlling enzymes. MethodsThe recombinant enzymes were kinetically characterized at physiological pH/temperature. Further, the pathway was in vitro reconstituted using enzyme activity ratios and fluxes similar to those observed in the parasites; then, enzyme and substrate titrations were performed to determine their degree of control on flux. Also, kinetic characterization of the whole pathway was performed. ResultsAnalyses of the kinetic properties indicated that TXN is the less efficient pathway enzyme derived from its high Kmapp for trypanothione and low Vmax values within the cell. MCA established that the TXN–TXNPx and TXN–GPxA redox pairs controlled by 90–100% the pathway flux, whereas 10% control was attained by TryR. The Kmapp values of the complete pathway for substrates suggested that the pathway flux was determined by the peroxide availability, whereas at high peroxide concentrations, flux may be limited by NADPH. ConclusionThese quantitative kinetic and metabolic analyses pointed out to TXN as a convenient drug target due to its low catalytic efficiency, high control on the flux of peroxide detoxification and role as provider of reducing equivalents to the two main peroxidases in the parasite. General SignificanceMCA studies provide rational and quantitative criteria to select enzymes for drug-target development.

Adsorption of enzyme onto lignins of liquid hot water pretreated hardwoods.

The adsorption of cellulase enzymes onto lignin is shown to be non-productive and therefore reduces enzymatic hydrolysis of liquid hot water pretreated cellulose. Among the enzyme components of Trichoderma reesei cellulase cocktail, β-glucosidase showed the strongest adsorption onto lignin. Only 2-18% of the initial β-glucosidase activity remained in the supernatant while 50-60% of cellobiohydrolase and endoglucanase activities were recovered after incubation with lignin. By increasing the pH to 5.5 and adding NaCl to a 200 mM, the free enzymes in the supernatant were increased but hydrolysis was not enhanced since optimal pH for enzymatic hydrolysis is at 4.8. Electrostatic interactions contributed to enzyme adsorption and their effect was most pronounced for T. reesei β-glucosidase which had high molecular weights (78-94 kDa) and high isoelectric points (pI 5.7-6.4). Since the enzyme components which are required to synergistically hydrolyze cellulose have different profiles (molecular weight, hydrophobicity and pI), they exhibit different adsorption behaviors with lignin, and thereby change the ratio of enzyme activities needed for synergism during cellulose hydrolysis. β-glucosidase from Aspergillus niger exhibits less adsorption than β-glucosidase from T. reesei. Supplemental addition of A. niger β-glucosidase to the enzyme mixture increases hydrolysis of pretreated hardwood by a factor of two. The analysis presented in this paper shows that lignins with higher guaiacyl content adsorb more cellulase enzymes, particularly β-glucosidase, and that adsorption of β-glucosidase onto lignin indirectly suppresses enzymatic hydrolysis of cellulose in pretreated hardwoods due to decreased hydrolysis of cellobiose which in turn accumulates and inhibits CBH.

Variation of soil microbial biomass C and hydrolytic enzyme activities in a rangeland ecosystem: are slope aspect and position effective?

This study was conducted to investigate the effects of slope aspect and position on microbial biomass C (MBC) and some hydrolytic enzyme activities involved in soil N, P, and S cycles in a rangeland ecosystem of west central Iran. Soil samples were collected from three slope positions (summit, backslope, and footslope) of contiguous north- and south-facing slopes. Results indicated higher silt and clay content, soil organic C (SOC), total N (TN), and C/N ratio on the north-facing slope. Furthermore, MBC, alkaline phosphomonoesterase (ALP), acid phosphomonoesterase (ACP), arylsulfatase (ARS), urease (URS), L-asparaginase (LAS), and L-glutaminase (LGL) activities were greater by 46.1, 65.9, 58.6, 59.6, 52.6, 62.8, and 65.7%, respectively, on the north-facing slope compared to the south-facing one. Higher ratios of enzyme activities to MBC were observed on the north-facing slope. In contrast, per cent of inorganic N and microbial quotient were greater on the south-facing slope. The activity of ALP, ACP, ARS along with SOC, TN, and MBC values decreased from summit to footslope. Overall, our findings indicate that north-facing slope and summit position support greater microbial biomass and hydrolytic diversity.

Predictive Performance of a Physiologically Based Pharmacokinetic Model of Busulfan in Children

A physiologically based pharmacokinetic (PBPK) model of the DNA-alkylating agent busulfan was slightly modified and scaled from adults to children in order to predict the systemic busulfan drug exposure in children. Capitalizing on the recent major software release of PK-Sim®, we refined our PBPK model by implementing glutathione S transferase (GST) in 11 organs using the software integrated enzyme expression database. In addition, two irreversible binding processes (i.e., DNA and plasma protein binding) were applied by using Koff and KD values. The model was scaled from adults to children. Simulations were computed and compared to concentration-time data after intravenous (i.v.) busulfan administration to 36 children. Based on the results, an age-dependent enzyme activity and maturation ratio was tailored and evaluated with an external dataset consisting of 23 children. Initial adult to children scaling indicated lower clearance values for children in comparison to adults. Subsequent age-dependent maturation ratio resulted in three different age groups: Activity of busulfan-glutathione conjugate formation was 80%, 61%, and 89% in comparison to adults for children with an age of up to 2 years, > 2–6 years, and > 6–18 years, respectively. Patients of the evaluation dataset were simulated with a mean percentage error (MPE) for all patients of 3.9% with 3/23 children demonstrating a MPE of > ±30%. The PBPK model parameterization sufficiently described the observed concentration-time data of the validation dataset while showing an adequate predictive performance. This PBPK model could be helpful to determine the first dose of busulfan in children.

GAL regulon ofSaccharomyces cerevisiaeperforms optimally to maximize growth on galactose

The GAL regulon in Saccharomyces cerevisiae is a well-characterized genetic network that is utilized for the metabolism of galactose as an energy source. The network contains a transcriptional activator, Gal4p, which binds to its cognate-binding site to express GAL genes. Further, Gal80p and Gal3p are the repressor and galactose sensor, respectively, which are also under the regulation of GAL regulon. It is shown that the wild-type strain produces only about 80% of the maximum expression feasible from the regulon, which is observed in a mutant strain lacking Gal80p. This raises a fundamental question regarding the optimality of expression from the GAL regulon in S.cerevisiae. To address this issue, we evaluated the burden on growth due to the synthesis of GAL proteins in S.cerevisiae. The analysis demonstrated that both the media type and the extent of enzyme synthesized play a role in determining the burden on growth. We show that the burden can be quantified by relating to a parameter, β, the ratio of enzyme activity to the initial substrate concentration. The analysis demonstrated that the GAL regulon of the wild-type strain performed effectively to optimize growth on galactose.

Carbon-Degrading Enzyme Activities Stimulated by Increased Nutrient Availability in Arctic Tundra Soils

Climate-induced warming of the Arctic tundra is expected to increase nutrient availability to soil microbes, which in turn may accelerate soil organic matter (SOM) decomposition. We increased nutrient availability via fertilization to investigate the microbial response via soil enzyme activities. Specifically, we measured potential activities of seven enzymes at four temperatures in three soil profiles (organic, organic/mineral interface, and mineral) from untreated native soils and from soils which had been fertilized with nitrogen (N) and phosphorus (P) since 1989 (23 years) and 2006 (six years). Fertilized plots within the 1989 site received annual additions of 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. Within the 2006 site, two fertilizer regimes were established – one in which plots received 5 g N⋅m-2⋅year-1 and 2.5 g P⋅m-2⋅year-1 and one in which plots received 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. The fertilization treatments increased activities of enzymes hydrolyzing carbon (C)-rich compounds but decreased phosphatase activities, especially in the organic soils. Activities of two enzymes that degrade N-rich compounds were not affected by the fertilization treatments. The fertilization treatments increased ratios of enzyme activities degrading C-rich compounds to those for N-rich compounds or phosphate, which could lead to changes in SOM chemistry over the long term and to losses of soil C. Accelerated SOM decomposition caused by increased nutrient availability could significantly offset predicted increased C fixation via stimulated net primary productivity in Arctic tundra ecosystems.

Examination of Digestive Enzyme Distribution in Gut Tract and Functions of Intestinal Caecum, in Megascolecid Earthworms (Oligochaeta: Megascolecidae) in Japan

Earthworms ingest various materials in addition to food items, such as soil particles. Most earthworms of the family Megascolecidae, a dominant family in Japan, have intestinal caeca connected directly to the intestinal tract. The function of the caeca has not been demonstrated, although it is thought to be associated with digestion. We investigated the activity of the digestive enzymes amylase, phosphatase, cellulase, and protease in different regions of the gut, including the intestinal caeca, in three species of megascolecid earthworms, Pheretima heteropoda, Pheretima hilgendorfi, and Pheretima sieboldi. Activities of several enzymes were high in the intestinal caeca; in particular, protease activity was higher in the caeca than that in the anterior gut, foregut, midgut, and hindgut in all three species. Moreover, the ratio of enzyme activities in the intestinal caeca to whole-gut tended to be higher in manicate intestinal caeca than in simple intestinal caeca. These results suggest that the digestive system of earthworms relies on the intestinal caeca.

Engineering of a bi-enzymatic reaction for efficient production of the ascorbic acid precursor 2-keto-l-gulonic acid

The enzymatic production of the vitamin C precursor 2-keto-l-gulonate (2-KLG) from 2,5-diketo-d-gluconate (2,5-DKG) was catalyzed by coupling 2,5-diketo-d-gluconic acid reductase (2,5-DKG reductase) via its coenzyme to glucose dehydrogenase. This bi-enzymatic process shows complicated inhibition patterns caused by reaction products, NADP+ and NADPH. The bioconversion was optimized by modeling. Rate equations were derived for both enzymes and solved simultaneously by a numerical method to predict 2-KLG production. A series of batch conversions were used to verify the model and construct isocharts to determine optimal process parameters. The following key parameters for a fast and efficient conversion were found: (1) the NADP(H) concentration, (2) the volumetric activity of 2,5-DKG reductase, (3) the ratio of synthetic enzyme activity to regenerate enzyme activity and (4) the glucono-1,5-lactone concentration. By modeling the space-time yield of the process was nearly doubled and the coenzyme concentration reduced threefold.

Isolation of α-amylase from malted rice (Wita 7) extract using cassava starch column procedure

The current study investigated the production and purification of α-amylase from malted rice (Wita 7) extract. In the course of the study, malting parameters such as germination energy, malt yield as well as malt loss of rice (Wita 7) were estimated. An appraisal of α-amylase production during malting with rice (Wita 7) revealed that, the production level peaked on the 8th day of germination with an estimated activity of 19.436 U/ml. The crude α-amylase from the 8th day malt extract was subsequently purified using starch column procedure. The purified extract recorded an estimated activity of 75.549 U/ml. The project further examined the effects of varying the ratios of starch adsorbent height to column diameter (L/D) during the purification step. For the columns employed (ID = 2.45 cm; 4.15 cm), the 2nd elution fractions from the experiments which were conducted with L/D ratios greater than 0.33 contained the highest amount of α-amylase. In summary, we have revealed that, the 8th day malt was most effective (optimum malting time) for starch hydrolysis. Again, the purification process produced a 4-fold enzyme activity ratio of 19:75. Finally, the greater the L/D ratio, the higher the efficacy for purification. Keywords : Alpha Amylase, Wita 7 rice, Malting, Starch adsorbent, Elution fraction African Journal of Biotechnology Vol. 12(23), pp. 3738-3744

Modelling aldehyde oxidase activity in aqueous-organic solvent mixtures at various temperatures

A model is proposed to represent the enzyme activity ratios in water – organic solvent mixtures at various temperatures. The prediction capability of the model was evaluated employing aldehyde oxidase as a model enzyme in seven water – organic solvent mixtures at 25, 35 and 45°C by using mean percentage deviation (MPD). The MPD obtained for each water – organic solvent mixture was 6.2%. A general model was also proposed employing the Abraham solvent parameters with MPD as 19.5%. The proposed models could be used in industry for speeding up the process designs where water – organic solvent mixtures at various temperatures were employed.

Regulatory polymorphisms in CYP2C19 affecting hepatic expression

Cytochrome P450 2C19 is responsible for the metabolism of many drugs, including the activation of clopidogrel. The allele CYP2C19*17 is associated with ultra-rapid metabolizer phenotypes by increasing gene transcription. This study tests to what extent CYP2C19*17 enhances CYP2C19 expression in human liver and whether additional regulatory variants contribute to variation in CYP2C19 expression. CYP2C19 mRNA was measured with quantitative real-time PCR (qRT-PCR), enzyme activity as metabolic velocity with S-mephenytoin as the substrate and allelic mRNA expression ratio with SNaPshot in human livers. CYP2C19 transcribed exons and a 4kb promoter region were sequenced using IonTorrent PGM or Sanger sequencing and screened for polymorphisms associated with total hepatic CYP2C19 mRNA, enzyme activity and allelic mRNA ratios. Livers heterozygote and homozygous for CYP2C19*17 had mRNA levels 1.8-fold (p=0.028) and 2.9-fold (p=0.006), respectively, above homozygous reference allele livers. CYP2C19*17 heterozygotes were also associated with increased allelic mRNA expression (allelic ratio ~1.8-fold, SD±0.6, p<0.005), whereas CYP2C19 enzyme activity was elevated 2.3-fold, with borderline significance (p=0.06) in CYP2C19*17 carriers. One liver sample of African ancestry displayed a 2-fold allelic expression ratio, and another sample, a ~12-fold increase in metabolic velocity. Neither case was accounted for by *17, which indicates the presence of additional regulatory variants. Our findings confirm *17 as a regulatory polymorphism enhancing hepatic CYP2C19 expression 2-fold with potential to compensate for the loss of function allele CYP2C19*2. Additional regulatory factors may also enhance CYP2C19 expression in African American populations.

Dynamic relationships between microbial biomass, respiration, inorganic nutrients and enzyme activities: informing enzyme-based decomposition models

We re-examined data from a recent litter decay study to determine if additional insights could be gained to inform decomposition modeling. Rinkes et al. (2013) conducted 14-day laboratory incubations of sugar maple (Acer saccharum) or white oak (Quercus alba) leaves, mixed with sand (0.4% organic C content) or loam (4.1% organic C). They measured microbial biomass C, carbon dioxide efflux, soil ammonium, nitrate, and phosphate concentrations, and β-glucosidase (BG), β-N-acetyl-glucosaminidase (NAG), and acid phosphatase (AP) activities on days 1, 3, and 14. Analyses of relationships among variables yielded different insights than original analyses of individual variables. For example, although respiration rates per g soil were higher for loam than sand, rates per g soil C were actually higher for sand than loam, and rates per g microbial C showed little difference between treatments. Microbial biomass C peaked on day 3 when biomass-specific activities of enzymes were lowest, suggesting uptake of litter C without extracellular hydrolysis. This result refuted a common model assumption that all enzyme production is constitutive and thus proportional to biomass, and/or indicated that part of litter decay is independent of enzyme activity. The length and angle of vectors defined by ratios of enzyme activities (BG/NAG vs. BG/AP) represent relative microbial investments in C (length), and N and P (angle) acquiring enzymes. Shorter lengths on day 3 suggested low C limitation, whereas greater lengths on day 14 suggested an increase in C limitation with decay. The soils and litter in this study generally had stronger P limitation (angles >45°). Reductions in vector angles to <45° for sand by day 14 suggested a shift to N limitation. These relational variables inform enzyme-based models, and are usually much less ambiguous when obtained from a single study in which measurements were made on the same samples than when extrapolated from separate studies.

Suivi des consommations de tabac et alcool après un premier cancer du poumon ou des voies aériennes supérieures : résultats préliminaires de l’étude ALTAK-1

A model is proposed to represent the enzyme activity ratios in water – organic solvent mixtures at various temperatures. The prediction capability of the model was evaluated employing aldehyde oxidase as a model enzyme in seven water – organic solvent mixtures at 25, 35 and 45 °C by using mean percentage deviation (MPD). The MPD obtained for each water – organic solvent mixture was 6.2%. A general model was also proposed employing the Abraham solvent parameters with MPD as 19.5%. The proposed models could be used in industry for speeding up the process designs where water – organic solvent mixtures at various temperatures were employed.

Organic matter inputs shift soil enzyme activity and allocation patterns in a wet tropical forest

Soil extracellular enzymes mediate organic matter turnover and nutrient cycling yet remain little studied in one of Earth's most rapidly changing, productive biomes: tropical forests. Using a long-term leaf litter and throughfall manipulation, we explored relationships between organic matter (OM) inputs, soil chemical properties and enzyme activities in a lowland tropical forest. We assayed six hydrolytic soil enzymes responsible for liberating carbon (C), nitrogen (N) and phosphorus (P), calculated enzyme activities and ratios in control plots versus treatments, and related these to soil biogeochemical variables. While leaf litter addition and removal tended to increase and decrease enzyme activities per gram soil, respectively, shifts in enzyme allocation patterns implied changes in relative nutrient constraints with altered OM inputs. Enzyme activity ratios in control plots suggested strong belowground P constraints; this was exacerbated when litter inputs were curtailed. Conversely, with double litter inputs, increased enzy- matic investment in N acquisition indicated elevated N demand. Across all treatments, total soil C correlated more strongly with enzyme activities than soluble C fluxes, and enzyme ratios were sensitive to resource stoichiometry (soil C:N) and N availability (net N mineralization). Despite high annual precipitation in this site (MAP *5 m), soil moisture positively correlated with five of six enzymes. Our results suggest resource availability regulates tropical soil enzyme activities, soil moisture plays an additional role even in very wet forests, and relative investment in C, N and P degrading enzymes in tropical soils will often be distinct from higher latitude ecosystems yet is sensitive to OM inputs.

The neuroprotective effect of acute moderate alcohol consumption on caspase-3 mediated neuroapoptosis in traumatic brain injury: The role of lysosomal cathepsin L and nitric oxide

Our aim in this study was to investigate the effect of moderate acute alcohol administration on cysteine protease mediated neuronal apoptosis and nitric oxide production in the traumatic brain injury. A total of 29 adult Sprague–Dawley male rats weighing 250–300g were used. The rats were allocated into four groups. The first group was the control (sham-operated) group in which only a craniotomy was performed, the others were alcohol, trauma and trauma+alcohol groups. Caspase-3 enzyme activity in the trauma group increased significantly in comparison with the control group. The alcohol given group showed a decreased caspase-3 enzyme activity compared to the trauma group. The level of caspase-3 enzyme activity in the alcohol+trauma group decreased in comparison to the trauma group. SF/FEL ratio of cathepsin-L enzyme activity in the trauma group was significantly higher than in the control group. Our results indicate that moderate alcohol consumption may have protective effects on apoptotic cell death after traumatic brain injury. Protective effects of moderate ethanol consumption might be related to inhibition of lysosomal protease release and nitric oxide production.

Effect of two patterns of forest rehabilitation on soil enzyme activity and its relationship with soil fertility

Soil enzyme activity and their seasonal variation-vertical distribution, the relationship between soil enzyme activity and soil fertility were measured on the two different patterns of forest rehabilitation with the methods of fixed sample plots, mechanical sampling and conventional enzyme activity- physicochemical characters determination. The results showed that the ranked order of urease and cellulose activity were Pleioblastus amarus plantation>Betula luminifera plantation>cropland, catalase activity was P. amarus plantation> cropland> B. luminifera plantation. The change of enzyme activity in B. luminifera plantation and P. amarusplantation was more acute than cropland, which showed that different utilization types had a close connection with soil enzyme activity. In the aspect of total amount in different soil layers, invertase, urease, cellulose and catalase activities were P. amarus plantation> B. luminifera plantation>cropland, which showed enzyme activity of slope farmland was improved in two patterns of forest rehabilitation. Rhizosphere effect showed the ratio of rhizospheric soil enzyme activity vs. non-rhizospheric soil enzyme activity (R/S value) of those four soil enzyme activities in B. luminifera plantation and P. amarus plantation were more than 1, which showed the two forests had high rhizosphere effect, and had a certain contribution to increase the soil enzyme activity. The enzyme activity is closely related with the soil fertility for forest rehabilitation and this indicated that enzyme activity could be used to characterize soil fertility, which had positive significance to improve the soil and biological fertility. Key words: Forest rehabilitation, soil enzyme, rhizosphere effect, soil fertility.