以比生长速率时间曲线为基础的生物群体生长数学模型

构建了一个描述限制性环境条件下生物群体生长规律的数学模型。模型中比生长速率(μ)是时间(t)的函数。模型可以很好地拟合多种生物或生物细胞群体生长的延迟期、指数期和稳定期。该模型参数少,模型参数生物学意义明确,计算简单。     

有机磷农药降解菌及其基因工程研究新进展

有机磷农药是目前我国使用量最大的农药,对农业的发展有重要的作用,但同时造成了严重的环境污染.利用微生物及其产生的降解酶来降解农药是行之有效的方法.随着分子生物学技术的深入利用,农药的微生物降解已在基因工程领域取得了很大进展.本文综述了有机磷农药降解微生物的筛选、降解酶和基因的克隆、基因工程菌的构建以及应用等几个方面的研究进展.     

一类具有时滞的微生物连续培养数学模型研究

研究了具有强核函数时滞的微生物连续培养数学模型,利用泛函微分方程理论和数值解法得到系统在一定操作条件下存在Hopf分叉以及分叉值随操作参数变化的规律,并研究了Hopf分叉产生的方向及周期解的稳定性,绘制了周期解的图形和相图.该模型定性地描述了实验中的振荡和过渡现象.最后与弱核函数时滞模型、离散时滞模型进行比较,分析了它们对多态、振荡等动态行为的影响。     

微生物降解农药研究的新进展

农药尤其是化学农药中高毒、高残留、难降解的农药是重要的环境污染物,而利用微生物治理农药所造成的环境污染是一项有效的手段。从降解农药的微生物的种类、工程菌的构建、微生物降解农药的机理、降解特性、影响因素及应用效果等多方面综述了近年来的研究进展,并提出了微生物降解农药研究领域的发展趋势和有待进一步解决的一些突出问题。     

微生物降解有机磷农药污染的研究进展

有机磷农药严重污染生态环境,微生物降解是治理有机磷农药污染的新技术,综述了降解有机磷农药污染的微生物种类、降解的机理、应用、存在的问题及今后研究方向。     

有机磷农药微生物降解研究进展

微生物降解是有机磷农药在环境中去毒降解的主要方式,是治理环境污染的一项有效手段。该文综述了有机磷农药降解菌的分离鉴定、降解机理与代谢途径、降解基因的克隆及表达、降解菌制剂和酶制剂的应用、以及有机磷农药微生物降解研究趋势五个方面的研究现状。     

新技术在农药微生物降解中的应用

近年来,分子生物学及基因工程的迅猛发展,克服了农药微生物降解传统研究中存在的障碍,为农药微生物降解的研究开辟了新的途径。综述了固定化技术、基因工程、多菌复合体的构建以及细胞表面展示技术在农药微生物降解中的应用,并对新技术在农药微生物降解中的应用前景作出了展望。     

微生物降解农药的研究新进展*

农药中,尤其化学农药中高毒、高残留、难降解的农药是重要的环境污染物,而微生物治理农药污染是一项有效手段,几十年来,在这方面已进行了大量研究。从农药降解菌的种类、工程菌的构建、微生物降解农药的机理、降解特性、影响因素及应用效果等几方面综述了近年这些方面的研究进展,并提出农药微生物降解研究领域的发展趋势和有待进一步解决的问题。     

稻田水质模型研究和应用进展

水稻生产环境特殊、生产过程中病虫草害严重,导致农药使用品种多、频次高.部分农药会淋失到周围水体中,对水体的潜在污染风险较高.随着农药监测和田间试验成本的不断提高,数学模型已成为农药登记过程中不可或缺的一部分.稻田水质模型(RICEWQ模型)作为欧洲稻田农药暴露评估最可靠和应用最广泛的模型,主要用于预测淹水稻田土壤和积水中的农药浓度,在我国也得到了初步应用.本文简要介绍了RICEWQ模型的系统结构、农药归趋的主要过程、模型的输入输出,综述了国内外相关的研究进展,以期推进RICEWQ模型在我国的应用,并为相关研究提供参考.     

环境中拟除虫菊酯类农药微生物降解技术研究进展

近年来,随着拟除虫菊酯类农药的大量及不合理使用,环境及食品中的农药残留对人类健康造成的负面影响日益显著。微生物降解农药作为去除农药污染安全高效的方法已成为当前研究热点之一。综述了国内外拟除虫菊酯类农药微生物降解菌的种类、降解机制、降解酶及降解菌应用的最新研究进展,并对亟须解决的重要问题进行了展望。     

Micro-scale modeling of pesticide degradation coupled to carbon turnover in the detritusphere: model description and sensitivity analysis

Microbiologically active biogeochemical interfaces are excellent systems to study soil functions such as pesticide degradation at the micro-scale. In particular, in the detritusphere pesticide degradation is accelerated by input of fresh organic carbon from litter into the adjacent soil. This observed priming effect suggests: (i) pesticide degradation is strongly coupled to carbon turnover, (ii) it is controlled by size and activity of the microbial community and (iii) sorption and transport of dissolved carbonaceous compounds and pesticides might regulate substrate availability and in turn decomposition processes. We present a new mechanistic 1D model (PEsticide degradation Coupled to CArbon turnover in the Detritusphere, PECCAD) which implements these hypotheses. The new model explicitly considers growth and activity of bacteria, fungi and specific pesticide degraders in response to substrate availability. Enhanced pesticide degradation due to availability of a second source of carbon (dissolved organic carbon) is implemented in the model structure via two mechanisms. First, additional substrate is utilized simultaneously with the pesticide by bacterial pesticide degraders resulting in an increase in their size and activity. Second, stimulation of fungal growth and activity by additional substrates leads directly to higher pesticide degradation via co-metabolism. Thus, PECCAD implicitly accounts for litter-stimulated production and activity of unspecific fungal enzymes responsible for co-metabolic pesticide degradation. With a global sensitivity analysis we identified high-leverage model parameters and input. In combination with appropriate experimental data, PECCAD can serve as a tool to elucidate regulation mechanisms of accelerated pesticide degradation in the detritusphere.     

Life prediction for a vacuum fluorescent display based on two improved models using the three‐parameter Weibull right approximation method

To obtain precise life information for vacuum fluorescent displays (VFDs), luminance degradation data for VFDs were collected from a group of normal life tests. Instead of exponential function, the three‐parameter Weibull right approximation method (TPWRAM) was applied to describe the luminance degradation path of optoelectronic products, and two improved models were established. One of these models calculated the average life by fitting average luminance degradation data, and the other model obtained VFD life by combining the approximation method with luminance degradation test data from each individual sample. The results indicated that the test design under normal working stress was appropriate, and the selection of censored test data was simple. The two models improved by TPWRAM both revealed the luminance decaying law for VFD, and the pseudo failure time was accurately extrapolated. It was further confirmed by comparing relative error that using the second model gave a more accurate prediction of VFD life. The improved models in this study can provide technical references for researchers and manufacturers in aspects of life prediction methodology for its development.     

Biodegradation and bioremediation of pesticide in soil: concept,method and recent developments

Biodegradation is a natural process, where the degradation of a xenobiotic chemical or pesticide by an organism is primarily a strategy for their own survival. Most of these microbes work in natural environment but some modifications can be brought about to encourage the organisms to degrade the pesticide at a faster rate in a limited time frame. This capability of microbe is some times utilized as technology for removal of contaminant from actual site. Knowledge of physiology, biochemistry and genetics of the desired microbe may further enhance the microbial process to achieve bioremediation with precision and with limited or no scope for uncertainty and variability in microbe functioning. Gene encoding for enzyme has been identified for several pesticides, which will provide a new inputs in understanding the microbial capability to degrade a pesticide and develop a super strain to achieve the desired result of bioremediation in a short time.     

Pesticide relevance and their microbial degradation: a-state-of-art

The extensive use of pesticide causes imbalance in properties of soil, water and air environments due to having problem of natural degradation. Such chemicals create diverse environmental problem via biomagnifications. Currently, microbial degradation is one of the important techniques for amputation and degradation of pesticide from agricultural soils. Some studies have reported that the genetically modified microorganism has ability to degrade specific pesticide but problem is that they cannot introduce in the field because they cause some other environmental problems. Only combined microbial consortia of indigenous and naturally occurring microbes isolated from particular contaminated environment have ability to degrade pesticides at faster rate. The bioaugumentation processes like addition of necessary nutrients or organic matter are required to speed up the rate of degradation of a contaminant by the indigenous microbes. The use of indigenous microbial strains having plant growth activities is ecologically superior over the chemical methods. In this review, we have attempted to discuss the recent challenge of pesticide problem in soil environment and their biodegradation with the help of effective indigenous pesticides degrading microorganisms. Further, we highlighted and explored the molecular mechanism for the pesticide degradation in soil with effective indigenous microbial consortium. This review suggests that the use of pesticide degrading microbial consortia which is an eco-friendly technology may be suitable for the sustainable agriculture production.     

Evolution of a metabolic pathway for degradation of a toxic xenobiotic: the patchwork approach

The pathway for degradation of the xenobiotic pesticide pentachlorophenol in Sphingomonas chlorophenolica probably evolved in the past few decades by the recruitment of enzymes from two other catabolic pathways. The first and third enzymes in the pathway, pentachlorophenol hydroxylase and 2,6-dichlorohydroquinone dioxygenase, may have originated from enzymes in a pathway for degradation of a naturally occurring chlorinated phenol. The second enzyme, a reductive dehalogenase, may have evolved from a maleylacetoacetate isomerase normally involved in degradation of tyrosine. This apparently recently assembled pathway does not function very well: pentachlorophenol hydroxylase is quite slow, and tetrachlorohydroquinone dehalogenase is subject to severe substrate inhibition.     

菌株DLL-1降解土壤和韭菜中甲基对硫磷的研究

施甲基对硫磷7．5、15和22．5kg·hm^-2(a．i．)时,韭菜中最终平均农药残留量为0．633、1．270和1．901mg·kg^-1,自然降解率分别为98．94％、96．44％和96．04％．施用高效农药残留降解菌剂能显著地降低农药残留的含量,施用75kg·hm^-2降解菌剂时,韭菜与土壤中平均农药残留量分别为0．269、0．099mg·kg^-1,与不施菌对照相比,能使农药进一步降低78．82％和98．68％．降解率随着菌剂用量增加而升高,当用量超过75kg·hm^-2时降解率不再提高．菌剂施用时间以施药后3d为最好．     

生态系统退化程度诊断：生态恢复的基础与前提

 生态系统退化程度诊断是进行生态恢复与重建的基础和前提。然而目前的生态系统化程度诊断大多停留在定性的水平,如何对退化生态系统的退化程度进行定量的诊断就成为恢复生态学与生态恢复实践所面临的一个迫切且十分关键的问题。在综述前人研究的基础上,比较系统地论述了生态系统退化程度诊断的一系列问题：绘制了描述生态系统退化程度的概念模型;认为在实践中退化程度诊断的参照系统可以选择相应的受人类或自然干扰程度比较轻的“自然生态系统”;归纳了生态系统退化程度诊断的生物途径、生境途径、生态过程途径、生态系统功能/服务途径、景观途径;把诊断方法分为单途径单因子诊断法、单途径多因子诊断法、多途径综合诊断法;分析了生态系统退化程度诊断的可能指标（体系）;给出了生态系统退化程度诊断的策略与流程,并对生态系统退化程度诊断及生态恢复过程中应注意的事项进行了讨论。建议我国加强典型生态系统退化程度的综合诊断研究。     

中国若干森林水文要素地理分布规律的模拟

利用全国各森林植被地理分布区水文要素的实验观测数据,应用多元统计回归和主分量分析等数学方法建立了描述中国森林水文要素与地理要素（经度、纬度、海拔）之间函数关系Ｆ的三维地学模型（ＤＴＭ）,其中包括：全国年均降水分布规律模拟模型;全国林冠降水截留规律模拟模型;全国森林枯落物持水能力模拟模型;中国森林综合截留能力指数模型。并且利用地理信息系统的三维地学模型（ＤＴＭ）成图功能,实现全国范围内的森林水文要素