Effects of Different Nitrogen Application Methods on Enzyme Activities in Leaves at Late Growth Stage of Spring Maize

[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superoxide dismutase （SOD） activity, peroxidase （POD） activity, malonyl dialdehyde （MDA） content and soluble protein content were determined. [Result] At the filling stage and ripening stage, with the increasing of nitrogen application rate, MDA content gradually decreased, while SOD activity, POD activity and soluble protein content increased. MDA content with two topdressing nitrogen was lower than that with one top dressing nitrogen at the same nitrogen application rate, while SOD activity, POD activity and soluble protein content with two topdressing nitrogen were higher than that with one topdressing nitrogen. [Conclusion] Different nitrogen application methods have relatively significant effects on the MDA content, SOD activity, POD activity and soluble protein content, which is of certain directive significance for preventing spring maize prematuration.

Application and Development of Biosensors

As a new kind of analytical instrument, the principles, types and characters of biosensors were discussed in this paper. A biosensor is usually composed of a recognition element of biological origin and a physicochemical transducer. The biological element is capable of sensing the presence, activity or concentration of a chemical analyse in solution. The sensing takes place either as a binding event or a biocatalytical event. These interactions produce a measurable change in a solution property, in which the transducer is converted into a quantifiable electrical signal. The principles, types and applications of biosensors in environmental inspection, food production, clinical medicine and military defense were reviewed, and the trends in research were predicated, Furthermore, an attempt had been made to describe the future development directions and prospects.

Mechanism and Application of Enzyme Treatment on Wool

Protease treatments on wool have its inherent defect in shrink-proofing because protease will decompose wool through cell membrane complex （CMC）. In order to solve this problem, mechanism of enzyme treatments on wool was adequately analyzed and possible enzyme applications were discussed. The mechanism of enzyme treatment on wool was analyzed through weight loss, strength, scanning electron microscopy （SEM）, electrophoresis, sodium dodecyl sulfate polyacrylamide gel electrophoresis （ SDS- PAGE）, and amino acids composition. Based on the results, a possible novel multifunetional enzyme treatment on wool to achieve shrink-resistance was proposed. In order to shorten enzyme treatment time, the rate of proteolysis of wool was investigated. Considering the specificity of proteases, wool composition, and structure of dyes, a better enzyme pretreatment before dyeing to get better dyeabflity and lower dyeing temperature was discussed.

FRACTALS OF HYBRID ORBITALS AND THEIR APPLICATIONS IN THE ENZYME MODELS

An enzyme is a kind of protein with catalytic activity and long chain,and its structure and shape are determined by the hybridized state of atomic orbital.The fractal dimension(D_f)is closely related to the hybridization,e.g.D_f=2ln2/ln[2(1+α/(1-α))]for the spa type, where a denotes the fraction of the s orbital in the hybridized molecular orbital.This relationship and the five fractal theorems introduced by the present paper play an important role in the investigations of the model of imitative enzyme.

A NOVEL POLYMER ENZYME LINKED IMMUNOASSAY METHOD AND ITS APPLICATIONS

During the course of study, we found that both poly (N-isopropylacrylamide ) (PNIP) and PNIP-Ab (enzyme-labelled antibody)could be adhere tightly to a cellulose acetale-nitrate membrane, and that the retention of PNIP-Ab on the membrane increased over 30-fold when compared with the unconjugated Ab.Thus we used this characteristic to develop a novel immunoassay method-polymer enzyme linked immunoassay method: homogeneous antigen-antibody reaction and heterogeneous separation process. When applied for detection of human serum HBsAg, this immunoassay system can detect as little as 1 ng/ml of human serum HBsAg.

Application of Enzyme Engineering in Pharmacy

Enzyme engineering is an important part of modern biotechnology.Due to its high reaction specificity,high efficiency,mild reaction conditions,and low pollution,it is also an important method widely used in the pharmaceutical field.The application of enzymes in medicine is diverse,such as:diagnosis,prevention and treatment of diseases with enzymes,manufacture of various drugs with enzymes,etc.,mainly through manual operations,to obtain enzymes required by the pharmaceutical industry,and through various means Enzymes perform their catalytic functions.This article mainly introduces the application of enzyme engineering in the pharmaceutical field,and also prospects the development trend of enzyme engineering in the pharmaceutical field.

Effects of the potassium application rate on lipid synthesis and eating quality of two rice cultivars

Lipid content has an important effect on rice eating quality,but the effects of fertilizer application rate on the lipid synthesis and eating quality of rice are not well understood.Potassium(K)has a strong influence on rice quality and the requirement for K fertilizer in rice is greater than for nitrogen(N)and phosphorus(P)fertilizers.To investigate the effects of K fertilizer on the lipid synthesis and eating quality of rice,we used Nanjing 9108(NJ9108,japonica)and IR72(indica)rice as experimental materials and four K levels:K0(0 kg ha^(-1)),K1(90 kg ha^(-1)),K2(135 kg ha^(-1))and K3(180 kg ha^(-1)).The results showed that the lipid content,free fatty acid(FFA)content,unsaturated fatty acid(UFA)content,malonyl-CoA(MCA)content,phosphatidic acid(PA)content,lipid synthesis-related enzyme activities and eating quality first increased and then decreased with increasing K in both cultivars.The maximum values were obtained under K2.However,the saturated fatty acid(SFA)content showed the opposite trend.No significant differences were found in pyruvate(PYR)content among the K treatments.The protein and oxaloacetic acid(OAA)contents and phosphoenolpyruvate carboxylase(PEPCase)activity of NJ9108 first decreased and then increased with increasing K,and the minimum values were obtained under K2;while IR72 showed the opposite trend and the maximum values were obtained under K1.Overall,increasing K optimized the fatty acid components and increased the lipid content and eating quality of rice by enhancing lipid synthesis-related enzyme activities and regulating substrate competition for lipid and protein synthesis.The optimal K application rate for lipid synthesis,eating quality and grain yield was 135 kg ha^(-1)for both cultivars.

Validation of a conductometric bienzyme biosensor for the detection of proteins as marker of organic matter in river samples

This article describes a conductometric bi-layer based bienzyme biosensor for the detection of proteins as a marker of organic matter in rivers. Proteins were chosen to be used as indicators of urban pollution. The working mechanism of the bienzyme biosensor is based on the enzymatic hydrolysis of proteins into several fractions （peptides and amino acids）, which results in a local conductivity change depending of the concentration of proteins. In this work, we began with the optimization of biosensor response using bovine serum albumin （BSA） as standard protein. For this objective seven enzymatic biosensors were prepared： four enzymatic sensors with only one layer of enzyme （proteinase K, trypsin, pronase or protease X） and three other enzymatic sensors with two layers （first layer： membrane containing proteinase K; second layer： one of the three other enzymes： trypsin, pronase or protease X）. The biosensors were obtained through the deposition of enzymatic layers and the cross-linking process between enzymes and BSA in saturated glutaraldehyde vapour. The response of the various biosensors, described previously, were compared with the values of total organic carbon （TOC）, and those of organic nitrogen （No~）, as determined by the laboratory accredits （CEMAGREF of Lyon） using the traditional method of analysis （NF EN 1484, infrared spectroscopy） and （NF EN 25663, mineralization/colorimetry assay） respectively for each water sample obtained from different sites in Lyon （France）. The linear correlations obtained with the response of the seven biosensors showed the most important indices of correlations for the biosensor with two enzymatic layers： proteinase K ＋ pronase （pkp）. The optimum conditions for the preparation of the pkp biosensor increased the sensitivity and gave a limit of quantification of 0.583 μg/L for TOC and 0.218 μg/L for Norg in water samples. This sensor shows good reproducibility （2.28%）, a capacity to be used at temperatures range 10-- 30℃ （depending on the season） and moreover a long lifetime （5 weeks）.

A New Application of Carbon Nanotubes Constructing Biosensor

Carbon nanotubes used for constructing biosensor was described for the first time. Single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups were used to immobilize glucose oxidase forming a glucose biosensor. The biosensor response can be determined by amperometric method at a low applied potential (0.40 V).

Analytical Expression for the Concentration of Substrate and Product in Immobilized Enzyme System in Biofuel/Biosensor

In this paper, an approximate analytical method to solve the non-linear differential equations in an immobilized enzyme film is presented. Analytical expressions for concentrations of substrate and product have been derived for all values of dimensionless parameter. Dimensionless numbers that can be used to study the effects of enzyme loading, enzymatic gel thickness, and oxidation/ reduction kinetics at the electrode in biosensor/biofuel cell performance were identified. Using the dimensionless numbers identified in this paper, and the plots representing the effects of these dimensionless numbers on concentrations and current in biosensor/biofuel cell are discussed. Analytical results are compared with simulation results and satisfactory agreement is noted.

Extraction of Pumpkin Polysaccharide by Complex Enzyme Method and Its Antioxidant Research

[Objective] This paper aims to study a new method of extracting pumpkin polysaccharide from pumpkin. Single factor experiments were conducted to examine the effects of extracting time,temperature,the solid-liquid ratio and pH value on the extraction yield of polysaccharide from pumpkin. [Method] The best enzyme ratio and extraction conditions for complex enzymes extraction were determined through orthogonal tests. Scavenging ·OH and O-2 activities of pumpkin polysaccharides were also investigated by salicylic acid and improved self-oxidation of o-pheno methods respectively. [Results] The results showed that the biggest extraction yield of polysaccharide from pumpkin can be got when adding 1% cellulose enzyme,1.5% pectinase,1.0% papain and Na2HPO4-citric acid buffer solution (pH was 4.6),and oscillating for 30 min under water at 40 ℃ with the solid-liquid ratio of 1:30. In addition,pumpkin polysaccharides had a strong activity of eliminating ·OH,but very weak activity to scavenge O-2. [Conclusion] This study provided basic data for research and application of Pumpkin polysaccharide.

Phage lytic enzymes: a history

There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of ‘bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well(Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specifi c disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay(Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes–from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.

Foliar Application of Benzothiadiazole and Salicylic Acid to Combat Sheath Blight Disease of Rice

A field study was undertaken to ascertain the effects of elicitors viz. benzothiadiazole （BTH） and salicylic acid （SA） on defense related enzymes viz. peroxidase, phenylalanine ammonia lyase, superoxide dismutase, chitinase and 13-1,3-glucanase, and phenols in rice （Pusa Basmati I） plants. First foliar spray of BTH （50 mg/kg） and SA （50 mg/kg） was done at the maximum tillering stage and inoculation with Rhizoctonia solani was carried 24 h after elicitor treatment. Elicitors were further sprayed at every growth stage. Time course analysis showed peak accumulation of defense related enzymes and phenols in the rice leaves treated with BTH and SA, and accumulation was the highest at the flowering stage. Higher enzymatic activity was observed in elicitor treated plants inoculated with R. solani. Compared to the untreated control plants, application of elicitors before R. solani inoculation significantly elicited the defense related enzymes and phenols. Moreover, application of elicitors had a positive effect on yield and disease reduction. It is suggested that pretreatment of rice leaves with BTH and SA could be used to enhance the level of protection against sheath blight and to improve rice yield in the fields.

Potential Applications of Milk Fractions and Valorization of Dairy By-Products: A Review of the State-of-the-Art Available Data, Outlining the Innovation Potential from a Bigger Data Standpoint

The unique composition of milk makes this basic foodstuff into an exceptional raw material for the production of new ingredients with desired properties and diverse applications in the food industry. The fractionation of milk is the key in the development of those ingredients and products;hence continuous research and development on this field, especially various levels of fractionation and separation by filtration, have been carried out. This review focuses on the production of milk fractions as well as their particular properties, applications and processes that increase their exploitation. Whey proteins and caseins from the protein fraction are excellent emulsifiers and protein supplements. Besides, they can be chemically or enzymatically modified to obtain bioactive peptides with numerous functional and nutritional properties. In this context, valorization techniques of cheese-whey proteins, by-product of dairy industry that constitutes both economic and environmental problems, are being developed. Phospholipids from the milk fat fraction are powerful emulsifiers and also have exclusive nutraceutical properties. In addition, enzyme modification of milk phospholipids makes it possible to tailor emulsifiers with particular properties. However, several aspects remain to be overcome;those refer to a deeper understanding of the healthy, functional and nutritional properties of these new ingredients that might be barriers for its use and acceptability. Additionally, in this review, alternative applications of milk constituents in the non-food area such as in the manufacture of plastic materials and textile fibers are also introduced. The unmet needs, the cross-fertilization in between various protein domains,the carbon footprint requirements, the environmental necessities, the health and wellness new demand, etc., are dominant factors in the search for innovation approaches;these factors are also outlining the further innovation potential deriving from those “apparent” constrains obliging science and technology to take them into account.

Research and Application Progress of Silk Fibroin Membranes

This paper mainly introduced the preparation of silk fibroin membranes and their structural change characteristics.Silk fibroin membranes can be used as tissue engineering materials,enzyme-immobilizing membranes,biosensors and drug controlled-release membranes and other different materials.They have excellent characteristics such as non-toxic,non-polluting and degradable,and thus have broad application prospects.

Therapeutic applications of collagenase(metalloproteases): A review

Non-invasive therapeutic methods have recently been used in medical sciences. Enzymes have shown high activity at very low concentrations in laboratories and pharmaceutical,enabling them to play crucial roles in different biological phenomena related to living organism, especially human medicine. Recently, using the therapeutic methods based on non-invasive approaches has been emphasized in medical society. Researchers have focused on producing medicines and tools reducing invasive procedures in medical.Collagenases are proteins which catalyze chemical processes and break the peptide bonds in collagen. Collagen may be generated more than the required amount or produced in unsuitable sites or may not degrade after a certain time. In such cases, using an injectable collagenase or its ointment can be helpful in collagen degradation. In both in vitro and in vivo tests, it has been revealed that collagenases have several therapeutic properties in wound healing, burns, nipple pain and some diseases including intervertebral disc herniation, keloid, cellulite, lipoma among others. This review describes the therapeutic application of collagenase in medical sciences and the process for its production using novel methods, paving the way for more effective and safe applications of collagenases.

Preliminary genome analysis of psychrotolerant marine bacterium Pseudoalteromonas sp. BSw20308 reveals its potential applications

The genus Pseudoalteromonas is ubiquitous in the marine environment and can synthesize a wide range of extracellular compounds. Psychrotolerant Pseudoalteromonas sp. BSw20308 was isolated from the Chukchi Sea, a marginal sea of the Arctic Ocean. It produces a number of extracellular enzymes that can degrade polysaccharides and proteins. The BSw20308 genome was sequenced to 38.1-fold coverage, and the sequences were assembled into 146 contigs （〉~500 bp）. In total, 4 172 open reading frames （ORFs） with an average gene length of 987 bp were detected. At least 86 ORFs were predicted by sequence analysis to encode a variety of catalytic modules involved in the degradation of polysaccharides, proteins, and lipids. In addition, 36 ORFs were predicted to encode catalytic modules involved in the degradation of organic pollutants and halogenated compounds, and in the production of bioactive compounds. The draft genome sequence of BSw20308 provides new information about the ecological function and adaptation of the genus Pseudoalteromonas in Arctic marine environments, and also indicates its potential applica- tions in the biotechnology industries （e.g., enzymology, and pollutant degradation）.

施钼对花生氮代谢关键酶活性、氮素利用及产量的影响

为分析施钼对花生氮代谢关键酶活性、氮素利用及产量的影响,采用盆栽和田间试验相结合的方式,设不施钼(0)、施钼(0.2 mg·kg^(-1))2个水平,研究了增施钼肥对花生关键生育时期氮代谢相关酶活性、植株氮素积累量、氮素利用率和产量的影响。盆栽试验和田间试验结果表明,与不施钼相比,增施钼肥显著提高了结荚期和成熟期花生根和叶片中硝酸还原酶、亚硝酸还原酶、谷氨酰胺合成酶和谷氨酸合成酶活性,显著增加了花生根系、地上部和荚果中氮素积累和荚果产量,其中,盆栽试验和田间试验两生育期氮素吸收效率分别平均提高47.79%和21.65%,氮素利用率分别平均提高10.58%和13.56%,花生分别显著增产38.20%和25.81%。可见,增施钼肥可显著提高花生根系和叶片氮素代谢相关酶活性,显著提高花生氮素积累量、氮素吸收利用效率和产量。增施钼肥是提高花生产量和氮利用率的有效措施。

微生物在生物基催化剂制备中的应用

随着工业催化过程对环境友好水平和效率需求的日益增长,微生物的功能多样性和环境适应性使其成为了生物基催化剂制备的理想选择。微生物以其固有的酶系统提供了一种高效、特异性强的催化方式,有利于生物基催化剂制备。微生物催化剂在药物合成、生物燃料生产和环境保护等多个领域展现了广泛的应用潜力。因此,文章将探讨微生物在生物基催化剂制备中的应用,以期为相关领域提供理论参考。

氮肥减量配施壳寡糖对棉花根系生长及根际土壤酶活性的影响

改善根际土壤环境以及促进棉花根系发育对棉花健康生长及产量和品质的提高意义重大。为探究氮肥减量配施壳寡糖促进棉花根系生长及调节土壤酶活性的作用,以盆栽试验和田间小区试验为研究方法,设置了不施肥、常规施肥(施N 400 kg/hm^(2)、P_(2)O_(5)140 kg/hm^(2)、K_(2)O 130 kg/hm^(2))、常规减氮20%施肥、常规减氮20%施肥+聚合度2~6型壳寡糖450 g/hm^(2)、常规减氮20%施肥+聚合度2~20型壳寡糖450 g/hm^(2)等5个处理,研究了氮肥减量配施不同聚合度类型壳寡糖对棉花根系生长和根际土壤酶活性的影响。结果表明,除土壤过氧化氢酶外,2个配施壳寡糖的处理均不同程度上降低了土壤脲酶、蔗糖酶、磷酸酶活性,其中酶活性降幅最大的为土壤磷酸酶,常规减氮20%施肥配施聚合度2~6型壳寡糖处理和常规减氮20%施肥配施聚合度2~20型壳寡糖处理分别比常规减氮20%施肥处理降低10.6%和5.5%。常规减氮20%施肥配施聚合度2~6型壳寡糖处理较常规减氮20%施肥处理土壤硝态氮含量增加了38.1%,而常规减氮20%施肥配施聚合度2~20型壳寡糖处理较常规减氮20%施肥处理土壤硝态氮含量降低了43.4%。并且施加聚合度2~6型、聚合度2~20型2种不同聚合度类型壳寡糖后,棉花根长较常规减氮20%施肥处理分别增加64.2%、40.1%,根表面积较常规减氮20%施肥处理增加74.8%、54.4%,根体积较常规减氮20%施肥处理增加106.2%和73.2%。由此可见,聚合度2~6型壳寡糖对促进棉花根系生长效果要优于聚合度2~20型壳寡糖。