Download or read book Differential Gene Expression by Two Strains of Escherichia Coli K12 and an Environmental Isolate in Response to Temperature and Nutrient Stress Using Microarrays written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study we evaluated the use of microarray technology in Bacterial Source Tracking (BST), with the intent of identifying candidate genes to be used to differentiate between closely related strains of Escherichia coli. We anticipate that genes differentially expressed in response to stress by both a laboratory strain and environmental isolate could be used as marker genes on a microarray in BST. Using microarrays we characterized the transcriptional response of E. coli K12 MG1655 (K12), maintained for about 80 years in an artificial environment versus E. coli 43(C)-4A or E43, a strain recently isolated from the natural environment. The responses were to a temperature decrease from 37C to 21C, and to growth in a diluted LB broth (dLB). Overall we found that there were more genes differentially expressed between the strains than either strain's response to the stresses. At the 4-fold threshold, at reduced temperature there were only 26 genes differentially regulated by K12 and 9 by E43, respectively. In K12 the functions of some differentially expressed genes were linked to the general stress response and biofilm formation. A few genes differentially expressed by E43 were involved in the stress response. Similarly, in response to dLB there were 46 and 11 genes differentially expressed by K12 and E43 respectively. While it appeared that genes differentially expressed by K12 were involved in dealing with nutrient deficiencies, the genes differentially expressed by E43 did not show a similar pattern. Of these genes, none were obvious candidate genes for a microarray to be used in BST. However, we did find that 169, 286 and 254 genes were differentially expressed between K12 and E43 at 37C, 21C, and in dLB, respectively. Many of these genes were differentially expressed under all 3 growth conditions. Several of the genes differentially expressed between the strains were in the O-antigen-lipopolysaccharide gene family and are genes that could potentially be used on a.
Download or read book Differential Gene Expression by Two Strains of Escherichia Coli K12 and an Environmental Isolate in Response to Temperature and Nutrient Stress Using Microarrays written by Charmaine Wetherell and published by . This book was released on 2009 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study we evaluated the use of microarray technology in Bacterial SourceTracking (BST), with the intent of identifying candidate genes to be used to differentiate between closely related strains of Escherichia coli. We anticipate that genes differentially expressed in response to stress by both a laboratory strain and environmental isolate could be used as marker genes on a microarray in BST. Using microarrays we characterized the transcriptional response of E. coli K12 MG1655 (K12), maintained for about 80 years in an artificial environment versus E. coli 43(C)-4A or E43, a strain recently isolated from the natural environment. The responses were to a temperature decrease from 37?C to 21?C, and to growth in a diluted LB broth (dLB). Overall we found that there were more genes differentially expressed between the strains than either strain's response to the stresses. At the 4-fold threshold, at reduced temperature there were only 26 genes differentially regulated by K12 and 9 by E43,respectively. In K12 the functions of some differentially expressed genes were linked to the general stress response and biofilm formation. A few genes differentially expressed by E43 were involved in the stress response. Similarly, in response to dLB there were 46 and 11 genes differentially expressed by K12 and E43 respectively. While it appeared that genes differentially expressed by K12 were involved in dealing with nutrient deficiencies, the genes differentially expressed by E43 did not show a similar pattern. Of these genes, none were obvious candidate genes for a microarray to be used in BST. However, we did find that 169, 286 and 254 genes were differentially expressed between K12 and E43 at 37?C, 21?C, and in dLB, respectively. Many of these genes were differentially expressed under all 3 growth conditions. Several of the genes differentially expressed between the strains were in the O-antigen-lipopolysaccharide gene family and are genes that could potentially be used on a microarray in BST. We found that E43, isolated from the natural environment, did not respond to the growth conditions in the same way as the model strain, E. coli K12, indicating that strains of E. coli isolated from the natural environment may not be identical to the model strain K12. It is suggested that other strains isolated from the natural environment be investigated. Such studies could also reveal genes differentially expressed between the strains that could be used on a microarray for use in BST.
Download or read book Stress Induced Mutagenesis written by David Mittelman and published by Springer Science & Business Media. This book was released on 2013-03-12 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery of stress-induced mutagenesis has changed ideas about mutation and evolution, and revealed mutagenic programs that differ from standard spontaneous mutagenesis in rapidly proliferating cells. The stress-induced mutations occur during growth-limiting stress, and can include adaptive mutations that allow growth in the otherwise growth-limiting environment. The stress responses increase mutagenesis specifically when cells are maladapted to their environments, i.e. are stressed, potentially accelerating evolution then. The mutation mechanism also includes temporary suspension of post-synthesis mismatch repair, resembling mutagenesis characteristic of some cancers. Stress-induced mutation mechanisms may provide important models for genome instability underlying some cancers and genetic diseases, resistance to chemotherapeutic and antibiotic drugs, pathogenicity of microbes, and many other important evolutionary processes. This book covers pathways of stress-induced mutagenesis in all systems. The principle focus is mammalian systems, but much of what is known of these pathways comes from non-mammalian systems.
Download or read book Cumulated Index Medicus written by and published by . This book was released on 2000 with total page 1840 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of the Escherichia Coli Transcriptome in Response to Environmental Stress written by Mugdha Gadgil and published by . This book was released on 2004 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstracts of the General Meeting of the American Society for Microbiology written by American Society for Microbiology. General Meeting and published by . This book was released on 2006 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Gene Expression in Escherichia Coli in Response to Oxygen Nitrate and Global Regulators of Transcription written by Rebecca Sophia Natalie Krupp and published by . This book was released on 2006 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies on Methylmalonyl CoA Mutasefrom Escherichia Coli written by Suresh M. Kannan and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methylmalonyl-CoA mutase (MCM, E.C. 5.4.99.2), a coenzyme B12-dependent enzyme, catalyses the. inter conversion of succinyl-CoA and methylmalonylCoA. The gene (sbm) encoding this enzyme is found in Escherichia coli (E. coll) at 62.3min on the E. coli chromosome. However, the metabolic role· of this enzyme in the organism is not kno~n. This project involves an investigation into this metabolic obscurity. The sbln gene is part of a four gene operon which also includes argK (or ygfD) that codes for a protein kinase catalysing the phosphorylation of two periplasmic binding proteins involved in cationic amino acid transport, ygfG that codes for methylmalonyl-CoA decarboxylase and ygfH that codes for propionyl-CoA: succinyl-CoA transferase. From existing literature we suspect that this operon, including the sbln gene, could be involved in the utilisation of unusual carbon sources such as succinate and propionate. An insertion mutant of the sbln gene created by transposon mediated mutagenesis was used for investigating the role of this gene. The wild type E. coli Kl2 strain, E. coli TR6524 and the mutant E. coli Kl2 (sbln::MudJ) were used in this study. Growth of the two strains (E. coli TR6524 and FAIPI) in minimal media with three different concentrations (0.05, 0.5, 5.0/lglmL) of vitamin B12 and in the presence succinate, propionate or glucose as the sole source of carbon, was studied. Growth was typical in media with glucose with no major differences in the growth pattern of the wild type and mutant strain. However, the two strains exhibited a differential growth pattern in media containing succinate, with the wild type growing faster than the mutant, indicating the role of the sbm gene in the utilisation of this carbon source. Growth in media containing propionate as the sole carbon source indicated only marginal differences in t1}.e growth pattern of the wild type and mutapt strain. This result possibly suggests that the other pathways for propionate utilisation in E. coli compensate for the lack of a functional Sbm protein in the mutant strain. Promoter analysis indicated the presence of a promoter induced by as, a transcription factor involved in the expression of proteins under stress or stationary phase growth conditions. Reverse transcription polymerase chain reaction (RT-PCR) studies of the genes of the sblll operon (sbm-argK-ygfGygfH) under the same growth conditions were carried out. Densitometric analysis of the PCR products suggested that the transcription level of sblll was higher in E. coli grown in succinate as compared to when grown in glucose and not as much when grown in propionate indicating a transcriptional level control of the sblll gene expression during the utilisation of succmate. RT-PCR studies also indicated a higher level of transcription of the gene in the stationary phase of the culture during the utilisation of succinate. Real time reverse transcription PCR (QPCR) analysis was used for the absolute quantification of the transcription of the genes of the sblll operon. An increase in the mRNA levels corresponding to the sbm, argK and ygfG genes was observed as E. coli TR6524 growth reached stationary phase, in the presence of succinate or propionate as the sole source of carbon as compared to glucose, In contrast, the highest mRNA levels corresponding to the ygfH gene were observed in the early log-phase of growth. This indicated a differential transcriptional level control of the genes within the operon. This study further established the possible role of this operon in the utilisation of succinate and propionate. The MCM enzyme activity measurement in the whole cell extracts of the wild type E. coli K12, grown under the above mentioned conditions, led to the fIrst ever measurement of MCM activity in wild type E. coli. These measurements also revealed a four fold increase of the MCM specific activity in the case of growth in succinate (4.76xlO-3U/mg) and a two fold increase for growth in propionate (2.79xlO-3U/mg) compared to that observed with growth in glucose (1.37xlO-3U/mg), indicating a significant level of involvement of the enzyme in succinate utilisation, and to a lesser extent in propionate utilisation. The proteomic analysis to understand the gene expression pattern of E. coli TR6524 was carried out using cells harvested at the stationary phase. The results showed that growth conditions induced the expression of transport related (HisJ, DppA) and energy generating proteins (PckA, AceF) required by E. coli to cope with the stressful growth conditions. However, Sbm was not identified among the limited protein spots that were analysed. Finally, E. coli K12 shm gene was successfully cloned into B. cereus Spy leading to the development of a metabolically engineered polyhydroxyalkanoate producing strain of B. cereus. The intention was to provide the bacteria with a natural intracellular source of propionyl-CoA, leading to the production of the P(3HB-co-3HV) copolymer from structurally non related carbon sources like glucose. Hence, this work has initiated investigation into the metabolic role of the shm gene product in E. coli. In addition, it has also led to the use of this gene product in metabolic engineering applications.
Download or read book Plants as alternative hosts for human and animal pathogens written by Nicola J. Holden and published by Frontiers Media SA. This book was released on 2015-07-02 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many of the most prevalent and devastating human and animal pathogens have part of their lifecycle out-with the animal host. These pathogens have a remarkably wide capacity to adapt to a range of quite different environments: physical, chemical and biological, which is part of the key to their success. Many of the well-known pathogens that are able to jump between hosts in different biological kingdoms are transmitted through the faecal-oral and direct transmission pathways, and as such have become important food-borne pathogens. Some high-profile examples include fresh produce-associated outbreaks of Escherichia coli O157:H7 and Salmonella enterica. Other pathogens may be transmitted via direct contact or aerosols are include important zoonotic pathogens. It is possible to make a broad division between those pathogens that are passively transmitted via vectors and need the animal host for replication (e.g. virus and parasites), and those that are able to actively interact with alternative hosts, where they can proliferate (e.g. the enteric bacteria). This research topic will focus on plants as alternative hosts for human pathogens, and the role of plants in their transmission back to humans. The area is particularly exciting because it opens up new aspects to the biology of some microbes already considered to be very well characterised. One aspect of cross-kingdom host colonisation is in the comparison between the hosts and how the microbes are able to use both common and specific adaptations for each situation. The area is still in relative infancy and there are far more questions than answers at present. We aim to address important questions underlying the interactions for both the microbe and plant host in this research topic.
Download or read book Index Medicus written by and published by . This book was released on 2002 with total page 1900 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Download or read book DNA Microarrays and Gene Expression written by Pierre Baldi and published by . This book was released on 2002-09-19 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concise, 2002 inter-disciplinary introduction to DNA microarray technology, which is revolutionizing biology and medicine.
Download or read book Stress Responses of Lactic Acid Bacteria written by Effie Tsakalidou and published by Springer Science & Business Media. This book was released on 2011-09-06 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with the basics of lactic acid bacteria and stress response, then working into specific fields of research and current developments, Stress Responses of Lactic Acid Bacteria will serve as an essential guidebook to researchers in the field, industry professionals, and advanced students in the area. The exploration of stress responses in lactic acid bacteria began in the early 90s and revealed the differences that exist between LAB and the classical model microorganisms. A considerable amount of work has been performed on the main genera / species of LAB regarding the genes implicated and their actual role and regulation, and the mechanisms of stress resistance have also been elucidated. Recent genome and transcriptome analyses complement the proteome and genetic information available today and shed a new light on the perception of and the responses to stress by lactic acid bacteria.
Download or read book Bacterial Chromatin written by Remus T. Dame and published by Springer Nature. This book was released on with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Genus Yersinia written by Robert D. Perry and published by Springer Science & Business Media. This book was released on 2007-09-25 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 9th International Symposium on Yersinia was held in Lexington, Kentucky, USA on October 10-14, 2006. Over 250 Yersinia researchers from 18 countries gathered to present and discuss their research. In addition to 37 oral presentations, there were 150 poster presentations. This Symposium volume is based on selected presentations from the meeting and contains both reviews and research articles. It is divided into six topic areas: 1) genomics; 2) structure and metabolism; 3) regulatory mechanisms; 4) pathogenesis and host interactions; 5) molecular epidemiology and detection; and 6) vaccine and antimicrobial therapy development. Consequently, this volume covers a wide range of current research areas in the Yersinia field.
Download or read book Desk Encyclopedia of Microbiology written by Moselio Schaechter and published by Academic Press. This book was released on 2010-04-19 with total page 1277 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Desk Encyclopedia of Microbiology, Second Edition is a single-volume comprehensive guide to microbiology for the advanced reader. Derived from the six volume e-only Encyclopedia of Microbiology, Third Edition, it bridges the gap between introductory texts and specialized reviews. Covering topics ranging from the basic science of microbiology to the current "hot" topics in the field, it will be invaluable for obtaining background information on a broad range of microbiological topics, preparing lectures and preparing grant applications and reports. - The most comprehensive single-volume source providing an overview of microbiology to non-specialists - Bridges the gap between introductory texts and specialized reviews - Provides concise and general overviews of important topics within the field making it a helpful resource when preparing for lectures, writing reports, or drafting grant applications
Download or read book Microbial Strategies for Crop Improvement written by Mohammad Saghir Khan and published by Springer Science & Business Media. This book was released on 2009-08-25 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an ever-increasing human population, the demand placed upon the agriculture sector to supply more food is one of the greatest challenges for the agrarian community. In order to meet this challenge, environmentally unfriendly agroch- icals have played a key role in the green revolution and are even today commonly recommended to circumvent nutrient de?ciencies of the soils. The use of ag- chemicals is, though, a major factor for improvement of plant production; it causes a profound deteriorating effect on soil health (soil fertility) and in turn negatively affects the productivity and sustainability of crops. Concern over disturbance to the microbial diversity and consequently soil fertility (as these microbes are involved in biogeochemical processes), as well as economic constraints, have prompted fun- mental and applied research to look for new agro-biotechnologies that can ensure competitive yields by providing suf?ciently not only essential nutrients to the plants but also help to protect the health of soils by mitigating the toxic effects of certain pollutants. In this regard, the role of naturally abundant yet functionally fully unexplored microorganisms such as biofertilizers assume a special signi?cance in the context of supplementing plant nutrients, cost and environmental impact under both conventional practices and derelict environments. Therefore, current devel- ments in sustainability involve a rational exploitation of soil microbial communities and the use of inexpensive, though less bio-available, sources of plant nutrients, which may be made available to plants by microbially-mediated processes.
Download or read book Regulation of Gene Expression by Small RNAs written by Rajesh K. Gaur and published by CRC Press. This book was released on 2009-04-27 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: New Findings Revolutionize Concepts of Gene FunctionEndogenous small RNAs have been found in various organisms, including humans, mice, flies, worms, fungi, and bacteria. Furthermore, it's been shown that microRNAs acting as cellular rheostats have the ability to modulate gene expression. In higher eukaryotes, microRNAs may regulate as much as 50 p
