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Metabolic Characteristics (metabolic + characteristic)
Selected AbstractsMetabolic characteristics of an isocitrate dehydrogenase defective derivative of escherichia coli BL21(DE3)BIOTECHNOLOGY & BIOENGINEERING, Issue 6 2003Miho Aoshima Abstract A 7.8 kb fragment containing isocitrate dehydrogenase (ICDH) gene and its flanking regions was cloned from Escherichia coli BL21(DE3) and sequenced. Unlike the case of the K-12 strain, the e14 element was not found. The nucleotide divergence between these two strains was about 2%. Using the cloned fragment, ICDH defective mutant strain, MA1935, was generated from BL21(DE3). Although MA1935 accumulated citrate, citrate synthase activity was not repressed but was rather high. In addition, isocitrate lyase was not highly induced at the stationary phase. MA1935 was shown to be a good host strain for ICDH gene expression. © 2003 Wiley Periodicals Inc. Biotechnol Bioeng84: 732,737, 2003. [source] A temperature-regulated Campylobacter jejuni gluconate dehydrogenase is involved in respiration-dependent energy conservation and chicken colonizationMOLECULAR MICROBIOLOGY, Issue 2 2008Mohanasundari Pajaniappan Summary Campylobacter jejuni is a gastrointestinal pathogen of humans but can asymptomatically colonize the avian gut. C. jejuni therefore grows at both 37°C and 42°C, the internal temperatures of humans and birds respectively. Microarray and proteomic studies on temperature regulation in C. jejuni strain 81,176 revealed the upregulation at 42°C of two proteins, Cj0414 and Cj0415, orthologous to gluconate dehydrogenase (GADH) from Pectobacterium cypripedii. 81,176 demonstrated GADH activity, converting d -gluconate to 2-keto- d -gluconate, that was higher at 42°C than at 37°C. In contrast, cj0414 and cj0415 mutants lacked GADH activity. Wild-type but not cj0415 mutant bacteria exhibited gluconate-dependent respiration. Neither strain grew in defined media with d -gluconate or 2-keto- d -gluconate as a sole carbon source, revealing that gluconate was used as an electron donor rather than as a carbon source. When administered to chicks individually or in competition with wild-type, the cj0415 mutant was impaired in establishing colonization. In contrast, there were few significant differences in colonization of BALB/c-ByJ mice in single or mixed infections. These results suggest that the ability of C. jejuni to use gluconate as an electron donor via GADH activity is an important metabolic characteristic that is required for full colonization of avian but not mammalian hosts. [source] Metabolic age modelling: the lesson from centenariansEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2000G. Paolisso Evolutionary theories of ageing, and data emerging from cellular and molecular biology of ageing, suggested that animals and humans capable of reaching an age close to the extreme limit of the life span should be equipped with a very efficient network of anti-ageing mechanisms. Indeed several evidences have demonstrated that starting from young to very old subjects, ageing is associated with a progressive remodelling. Thus, a new paradigm, the remodelling theory of age, was proposed. This theory, focusing on the human immune system, suggested that immunosenescence is the net result of the continuous adaptation of the body to the deteriorative changes occurring over time. According to this hypothesis, body resources are continuously optimized, and immunosenescence must be considered a very dynamic process including both loss and gain. Whether the metabolic pathways and the endocrine functions are also part of the age remodelling is not investigated. The aim of this review is to focus on the age-related changes in metabolic pathways and endocrine functions and to demonstrate that healthy centenarians (HC) represent the best living example of successful age-remodelling in whom the age remodelling has occurred without problems. In order to design the clinical picture of such successful ageing, anthropometric, endocrine and metabolic characteristics of healthy centenarians (HC), compared with aged subject, have been outlined. [source] The Human Ageing Genomic Resources: online databases and tools for biogerontologistsAGING CELL, Issue 1 2009Joćo Pedro De Magalhćes Summary Aging is a complex, challenging phenomenon that requires multiple, interdisciplinary approaches to unravel its puzzles. To assist basic research on aging, we developed the Human Ageing Genomic Resources (HAGR). This work provides an overview of the databases and tools in HAGR and describes how the gerontology research community can employ them. Several recent changes and improvements to HAGR are also presented. The two centrepieces in HAGR are GenAge and AnAge. GenAge is a gene database featuring genes associated with aging and longevity in model organisms, a curated database of genes potentially associated with human aging, and a list of genes tested for their association with human longevity. A myriad of biological data and information is included for hundreds of genes, making GenAge a reference for research that reflects our current understanding of the genetic basis of aging. GenAge can also serve as a platform for the systems biology of aging, and tools for the visualization of protein,protein interactions are also included. AnAge is a database of aging in animals, featuring over 4000 species, primarily assembled as a resource for comparative and evolutionary studies of aging. Longevity records, developmental and reproductive traits, taxonomic information, basic metabolic characteristics, and key observations related to aging are included in AnAge. Software is also available to aid researchers in the form of Perl modules to automate numerous tasks and as an SPSS script to analyse demographic mortality data. The HAGR are available online at http://genomics.senescence.info. [source] Diffusely elevated cerebral choline and creatine in relapsing-remitting multiple sclerosisMAGNETIC RESONANCE IN MEDICINE, Issue 1 2003Matilde Inglese Abstract It is well known that multiple sclerosis (MS) pathogenesis continues even during periods of clinical silence. To quantify the metabolic characteristics of this activity we compared the absolute levels of N -acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the normal-appearing white matter (NAWM) between relapsing-remitting (RR) MS patients and controls. Metabolite concentrations were obtained with 3D proton MR spectroscopy at 1.5 T in a 480 cm3 volume-of-interest (VOI), centered on the corpus callosum of 11 MS patients and 9 matched controls. Gray/white-matter/cerebral-spinal-fluid (CSF) volumes were obtained from MRI segmentation. Patients' average VOI tissue volume (VT), 410.8 ± 24.0 cm3, and metabolite levels, NAA = 6.33 ± 0.70, Cr = 4.67 ± 0.52, Cho = 1.40 ± 0.17 mM, were different from the controls by ,8%, ,9%, +22% and +32%. The Cho level was the only single metric differentiating patients from controls at 100% specificity and >90% sensitivity. Diffusely elevated Cho and Cr probably reflect widespread microscopic inflammation, gliosis, or de- and remyelination in the NAWM. Both metabolites are potential prognostic indicators of current disease activity, preceding NAA decline and atrophy. Magn Reson Med 50:190,195, 2003. © 2003 Wiley-Liss, Inc. [source] | |||||||||||||