The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform

Rakesh K. Jain - One of the best experts on this subject based on the ideXlab platform.

  • Conceptualizing "suicidal Genetically Engineered Microorganisms" for bioremediation applications.
    Biochemical and biophysical research communications, 2005
    Co-Authors: Gunjan Pandey, Debarati Paul, Rakesh K. Jain
    Abstract:

    Use of Genetically modified Microorganisms (GEMs) for pollution abatement has been limited because of risks associated with their release in the environment. Recent developments in the area of recombinant DNA technologies have paved the way for conceptualizing "suicidal Genetically Engineered Microorganisms" (S-GEMS) to minimize such anticipated hazards and to achieve efficient and safer bioremediation of contaminated sites. Our strategy of designing a novel S-GEM is based on the knowledge of killer-anti-killer gene(s) that would be susceptible to programmed cell death after detoxification of any given contaminated site(s).

  • Suicidal Genetically Engineered Microorganisms for bioremediation: Need and perspectives
    BioEssays : news and reviews in molecular cellular and developmental biology, 2005
    Co-Authors: Debarati Paul, Gunjan Pandey, Rakesh K. Jain
    Abstract:

    In the past few decades, increased awareness of environmental pollution has led to the exploitation of microbial metabolic potential in the construction of several Genetically Engineered Microorganisms (GEMs) for bioremediation purposes. At the same time, environmental concerns and regulatory constraints have limited the in situ application of GEMs, the ultimate objective behind their development. In order to address the anticipated risks due to the uncontrolled survival/dispersal of GEMs or recombinant plasmids into the environment, some attempts have been made to construct systems that would contain the released organisms. This article discusses the designing of safer Genetically Engineered organisms for environmental release with specific emphasis on the use of bacterial plasmid addiction systems to limit their survival thus minimizing the anticipated risk. We also conceptualize a novel strategy to construct "Suicidal Genetically Engineered Microorganisms (SGEMs)" by exploring/combining the knowledge of different plasmid addiction systems (such as antisense RNA-regulated plasmid addiction, proteic plasmid addiction etc.) and inducible degradative operons of bacteria.

C. Richard Hutchinson - One of the best experts on this subject based on the ideXlab platform.

  • Drug synthesis by Genetically Engineered Microorganisms.
    Nature Biotechnology, 1994
    Co-Authors: C. Richard Hutchinson
    Abstract:

    The interplay between chemical and biological approaches to drug discovery and development is increasing with the advent of combinatorial methods that accelerate the output of screening programs and the development of Genetically modified Microorganisms able to make new metabolites and larger amounts of known ones. Actinomycetes, the most prolific microbial source of known drugs, can produce new aromatic compounds by manipulation of the Type II polyketide synthase genes as well as analogs of existing macrolide antibiotics, unavailable by chemical synthesis, through targeted mutation of specific biosynthetic genes. Genetic alteration of pathways to aminoglycoside and oligopeptide antibiotics should offer equally promising approaches to manufacturing novel metabolites. When coupled with DNA–based prescreening of microbial isolates for genes associated with known pharmacologically active agents, these new genetic–based approaches are creating an expanded role for Microorganisms in drug research.

Janet K. Jansson - One of the best experts on this subject based on the ideXlab platform.

  • Tracking Genetically Engineered Microorganisms in nature.
    Current opinion in biotechnology, 1995
    Co-Authors: Janet K. Jansson
    Abstract:

    The past year has seen the continued development of methods for tracking Genetically Engineered Microorganisms in nature, with an emphasis on increased sensitivity, specificity and quantitative ability. In addition, novel methods have been developed for tagging bacteria targeted for environmental release. Nevertheless, the limited number of field trials published to date have primarily relied on conventional monitoring methods, despite the availability of better and theoretically safer methods.

G Stotzky - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Genetically Engineered Microorganisms on microbial populations and processes in natural habitats.
    Advances in applied microbiology, 1995
    Co-Authors: Jack D. Doyle, G Stotzky, Gwendolyn Mcclung, Charles W. Hendricks
    Abstract:

    Publisher Summary This chapter discusses the effects of Genetically Engineered Microorganisms on microbial populations and process in natural habitats. The chapter illustrates that there is a relatively limited number of studies on the survival of and gene transfer by Genetically Engineered Microorganisms (GEMs) in natural environments. In addition, few studies are conducted on the effects of non-Engineered Microorganisms introduced to the environment, for example biocontrol agents, rhizobia for dinitrogen fixation, pure cultures and consortia for the degradation of xenobiotics and other aspects of bioremediation, and coal scrubbing. The chapter explores that the fundamental concern in the release to the environment of Microorganisms, whether Genetically altered or not, should be the potential ecological effects of these releases. The effects that GEMs may have on the structure and function of an ecosystem can also be affected by their mode of introduction, their spatial and temporal distribution, and the physicochemical and biological characteristics of the environment to which they are released. The chapter discusses the brief review and evaluation of the few studies that have been conducted on the ecological effects of the release of GEMs to aquatic and terrestrial environments are presented, to illustrate the current, and inadequate, state of knowledge on the potential impacts of GEMs on the environment.

  • Selected Methods for the Detection and Assessment of Ecological Effects Resulting from the Release of Genetically Engineered Microorganisms to the Terrestrial Environment
    Advances in Applied Microbiology, 1993
    Co-Authors: G Stotzky, M W Broder, J.d. Doyle, R A Jones
    Abstract:

    Publisher Summary This chapter discusses some selected methods for the detection and assessment of ecological effects resulting from the release of Genetically Engineered Microorganisms to the terrestrial environment. The chapter explains the methods and concepts developed to study the potential effects of Genetically Engineered Microorganisms (GEMs) on microbial populations and microbe-mediated ecological processes in soil. The potential impacts of GEMs, unrelated to the purposes for which they are Engineered, on the structure and function of the natural environments into which they are introduced constitute the bottom-line concern about the release of GEMs to the environment. The results in the chapter indicates that the introduction of GEMs into soil without the substrates on which the enzymatic products of the novel genes function or without the specific inhibitors to which the products confer resistance is insufficient to evaluate adequately the potential ecological effects of GEMs. In addition, the lack of appropriate theories and methodologies constitutes a major deficit in microbial ecology in general and, specifically, in risk assessment of the release of GEMS to the environment. The development of such theories and methodologies must be of high priority.

  • effects of Genetically Engineered Microorganisms on nitrogen transformations and nitrogen transforming microbial populations in soil
    Applied and Environmental Microbiology, 1991
    Co-Authors: R A Jones, M W Broder, G Stotzky
    Abstract:

    The principal concern about releasing Genetically Engineered Microorganisms (GEMs) into the environment is their potential adverse effects on the environment, whether caused directly or indirectly by the GEMs. The effects of five GEMs on ammonification, nitrification, and denitrification in soil were studied. With the possible exception of a strain of Enterobacter cloacae carrying a plasmid, no consistent statistically or ecologically significant differences in effects on these processes or on the population dynamics of the Microorganisms responsible for the processes were observed between soils inoculated with the GEMs or their homologous plasmidless hosts and those that were not inoculated. Increasing the concentration of montmorillonite in the soil enhanced the rate of nitrification, regardless of the inoculum, indicating that the perfusion technique used was sensitive enough to detect changes in nitrification rates when they occurred.

Masanori Fujita - One of the best experts on this subject based on the ideXlab platform.

  • Operation parameters affecting the survival of Genetically Engineered Microorganisms in activated sludge processes
    Water Research, 1994
    Co-Authors: Masanori Fujita, Michihiko Ike, Kazuya Uesugi
    Abstract:

    Abstract The survival of Genetically Engineered Microorganisms (GEMs) harboring recombinant plasmid pBH500, containing catechol 2,3-oxygenase encoding gene, in model activated sludge processes was investigated. Escherichia coli C600 (pBH500) and Pseudomonas putida BH(pBH500) were inoculated into activated sludge and cultivated in the fill and draw (FD) and continuous flow (CF) systems under different conditions. In both systems, the populations of introduced GEMs declined rapidly during the initial period (5–10 days for the FD system and 5–15 days for the CF system), after which they remained relatively stable. In the FD system, the larger the inoculum size, the higher the population level at which the GEMs remained stable. However, in the CF system, repeated inoculation did not improve the survival of P. putida BH(pBH500). The sludge retention time (SRT) affected the survival of GEMs considerably in both systems; as the SRT of the system was decreased, the survival populations of GEMs increased. The presence of phenol, which can support the growth of P. putida BH(pBH500), did not influence its survival.

  • feasibility of wastewater treatment using Genetically Engineered Microorganisms
    Water Research, 1991
    Co-Authors: Masanori Fujita, Michihiko Ike, S Hashimoto
    Abstract:

    Abstract The feasibility of wastewater treatment using Genetically Engineered xenobiotic-degrading Microorganisms was discussed. The degradation activity and the plasmid stability of some Escherichia coli and Pseudomonas putida strains harboring the recombinant plasmids containing salicylate oxidase gene or catechol 2,3 oxygenase gene were investigated. A few recombinants showed higher degradation activity than those of the wild strains. On the other hand, the recombinant plasmids were unstable in the absence of selective pressure. Both the degradation activity and the plasmid stability were affected considerably by the combination of plasmids and recipients. In another experiment, NAH plasmid was transferred into a floc-forming bacteria, Pseudomonas lemoignei 551 by conjugation, and floc-forming and salicylate-degrading bacteria were bred. This Genetically Engineered bacteria which grows flocculently seems to be maintained stably in activated sludge or in the wastewater treatment process. From these experimental results, the availability of the application of GEMs was demonstrated, and the possibility of solving two major problems, the genetic stability and the ecological stability, was suggested.