• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1529-1536
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• 2008

Acetylation of lysine residues in proteins is a reversible and highly regulated posttranslational modification. However, it has not been systematically studied in prokaryotes. By affinity immunoseparation using an anti-acetyllysine antibody together with nano-HPLC/MS/MS, we identified 125 lysine-acetylated sites in 85 proteins among proteins derived from Escherichia coli. The lysine-acetylated proteins identified are involved in diverse cellular functions including protein synthesis, carbohydrate metabolism, the TCA cycle, nucleotide and amino acid metabolism, chaperones, and transcription. Interestingly, we found a higher level of acetylation during the stationary phase than in the exponential phase; proteins acetylated during the stationary phase were immediately deacetylated when the cells were transferred to fresh LB culture medium. These results demonstrate that lysine acetylation is abundant in E. coli and might be involved in modifying or regulating the activities of various enzymes involved in critical metabolic processes and the synthesis of building blocks in response to environmental changes.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권4호
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• pp.221-228
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• 2016

The gastrointestinal exposome represents the integration of all xenobiotic components and host-derived endogenous components affecting the host health, disease progression and ultimately clinical outcomes during the lifespan. The human gut microbiome as a dynamic exposome of commensalism continuously interacts with other exogenous exposome as well as host sentineling components including the immune and neuroendocrine circuit. The composition and diversity of the microbiome are established on the basis of the luminal environment (physical, chemical and biological exposome) and host surveillance at each part of the gastrointestinal lining. Whereas the chemical exposome derived from nutrients and other xenobiotics can influence the dynamics of microbiome community (the stability, diversity, or resilience), the microbiomes reciprocally alter the bioavailability and activities of the chemical exposome in the mucosa. In particular, xenobiotic metabolites by the gut microbial enzymes can be either beneficial or detrimental to the host health although xenobiotics can alter the composition and diversity of the gut microbiome. The integration of the mucosal crosstalk in the exposome determines the fate of microbiome community and host response to the etiologic factors of disease. Therefore, the network between microbiome and other mucosal exposome would provide new insights into the clinical intervention against the mucosal or systemic disorders via regulation of the gut-associated immunological, metabolic, or neuroendocrine system.

• Toxicological Research
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• 제17권
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• pp.83-88
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• 2001

Most reactive oxygen species (ROS) are free radicals and implicated in the development of a number of disease processes including artherosclerosis, neurodegenerative disorders, aging and cancer. ROS are byproducts of a number of in vivo metabolic processes and are formed deliberately as part of nor-mal inflammatory response. On the other hand, ROS are generated either as by products of oxygen reduction during xenobiotic metabolism or are liberated as the result of the futile redox cycling of the chemical agents including several chemical carcinogens. A better understanding of the mechanisms of free radical toxicity may yield valuable clue to risks associated with chemical exposures that leading to the development of chronic diseases including cancer. The molecular biology of ROS-mediated alterations in gene expression, signal transduction and carcinognesis is one of the important subjects in free radical toxicology. Epidemiological studies suggest that high intake of vegetables and fruits are associated with the low incidence of human cancer. Many phytopolyphenols such as tea polyphenols, curcumin, resveratrol, apigenin, genistein and other flavonoids have been shown to be cancer chemopreventive agents. Most of these compounds are strong antioxidant and ROS scavengers in vitro and effective inducers of antioxidant enzymes such as superoxide dismutatse, catalase and glutathione peroxidase in vivo. Several cellular transducers namely receptor tyrosine kinase, protein kinase C, MAPK, PI3K, c-jun, c-fos, c-myc, NFkB, IkB kinase, iNOS, COX-2, Bcl-2, Bax, etc have been shown to be actively modulated by phyto-polyphenols. Recent development in free radical toxicology have provided strong basis for understanding the action mechanisms of cancer chemoprevention.

• Journal of Microbiology and Biotechnology
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• 제19권8호
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• pp.836-844
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• 2009

A denitrification bacterium was isolated from riverbed soil and identified as Ochrobactrum sp., whose specific enzymes for denitrification metabolism were biochemically assayed or confirmed with specific coding genes. The denitrification activity of strain G3-1 was proportional to glucose/nitrate balance, which was consistent with the theoretical balance (0.5). The modified graphite felt cathode with neutral red, which functions as a solid electron mediator, enhanced the electron transfer from electrode to bacterial cell. The porous carbon anode was coated with a ceramic membrane and cellulose acetate film in order to permit the penetration of water molecules from the catholyte to the outside through anode, which functions as an air anode. A non-compartmented electrochemical bioreactor (NCEB) comprised of a solid electron mediator and an air anode was employed for cultivation of G3-1 cells. The intact G3-1 cells were immobilized in the solid electron mediator, by which denitrification activity was greatly increased at the lower glucose/nitrate balance than the theoretical balance (0.5). Metabolic stability of the intact G3-1 cells immobilized in the solid electron mediator was extended to 20 days, even at a glucose/nitrate balance of 0.1.

• 한국식품위생안전성학회지
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• 제10권3호
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• pp.163-168
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• 1995

The present study has been undertaken to investigate the effects of garlic added to food on the activities of several enzymes in serum of rats fed lard and alcohol. Thirty-five males of Sprague-Dawley strains weighed about 130g were divided into 7 groups, each group receiving a different diet for 10 weeks; i.e. basal diet plus 15% lard, basal diet plus 5% alcohol, basal diet plus 0.5% garlic, basal diet plus 15% lard and 0.5% garlic. Determinations were carried out in the net weight gain, food efficiency ratio, weight of organs, and AST, ALT, lactate dehydrogenase, alkaline phosphatase activities in serum of rats. The results obtained were as follows; Rats given feed containing lard and alcohol showed significant decrease in net weight gain, but garlic caused an increased in food efficiency ratio. Lard supplementation caused an increase in the weight of liver, kidney, spleen, but another groups did not, AST, ALT, ALP, LDH of serum were significantly increased in lard and alcohol containing group but garlic feeding decreased enzyme activities compared to lard and alcohol containing group. The above results suggest that garlic would prevent the metabolic disease of liver by improving hyperlipemia caused by high fat diet.

• Mass Spectrometry Letters
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• 제9권3호
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• pp.86-90
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• 2018

Methallylescaline, 2-(3,5-dimethoxy-4-[(2-methylprop-2-en-1-yl)oxy]phenyl)ethanamine, is a new psychoactive substance with potent agonist of 5-HT receptor, but there is little information on its pharmacological effect, metabolism, and toxicity. It is necessary to characterize the metabolic profiling of methallylescaline in human hepatocytes using liquid chromatography-high resolution mass spectrometry. Methallylescaline was metabolized to three hydroxy-methallylescaline (M1-M3) and dihydroxy-methallylescaline (M4) via hydroxylation in human hepatocytes. CYP2D6, CYP2J2, CYP1A2, and CYP3A4 enzymes were responsible for the metabolism of methallylescaline. The metabolites as well as methallylescaline would be used for monitoring the abuse of methallylescaline.

• Journal of Microbiology and Biotechnology
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• 제17권6호
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• pp.897-904
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• 2007

The aim of this paper is to discuss the methodology of our investigation of the dynamics of protein degradation and the total in situ protealytic activity in meso/eutrophic, eutrophic, and hypereutrophic freshwater environments. Analysis of the kinetics and rates of enzymatic release of amino acids in water samples preserved with sodium azide allows determination of the concentrations of labile proteins $(C_{LAB})$, and their half-life time $(T_{1/2})$. Moreover, it gives more realistic information on resultant activity in situ $(V_{T1/2})$ of ecto- and extracellular proteases that are responsible for the biological degradation of these compounds. Although the results provided by the proposed method are general y well correlated with those obtained by classical procedures, they better characterize the dynamics of protein degradation processes, especially in eutrophic or hypereutrophic lakes. In these environments, processes of protein decomposition occur mainly on the particles and depend primarily on a metabolic activity of seston-attached bacteria. The method was tested in three lakes. The different degree of eutrophication of these lakes was clearly demonstrated by the measured real proteolytic pattern and confirmed by conventional trophic state determinants.

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.330-337
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• 2018

Polycyclic aromatic hydrocarbons (PAHs), including naphthalene, are widely distributed in nature. Naphthalene has been regarded as a model PAH compound for investigating the mechanisms of bacterial PAH biodegradation. Pseudomonas sp. AS1 isolated from an arseniccontaminated site is capable of growing on various aromatic compounds such as naphthalene, salicylate, and catechol, but not on gentisate. The genome of strain AS1 consists of a 6,126,864 bp circular chromosome and the 81,841 bp circular plasmid pAS1. Pseudomonas sp. AS1 has multiple dioxygenases and related enzymes involved in the degradation of aromatic compounds, which might contribute to the metabolic versatility of this isolate. The pAS1 plasmid exhibits extremely high similarity in size and sequences to the well-known naphthalene-degrading plasmid pDTG1 in Pseudomonas putida strain NCIB 9816-4. Two gene clusters involved in the naphthalene degradation pathway were identified on pAS1. The expression of several nah genes on the plasmid was upregulated by more than 2-fold when naphthalene was used as a sole carbon source. Strains have been isolated at different times and places with different characteristics, but similar genes involved in the degradation of aromatic compounds have been identified on their plasmids, which suggests that the transmissibility of the plasmids might play an important role in the adaptation of the microorganisms to mineralize the compounds.

• Journal of Applied Biological Chemistry
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• 제54권2호
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• pp.101-107
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• 2011

Aging in females is associated with a reduced metabolic function, increased incidence of neurodegenerative diseases, and cognitive dysfunction, as a result of loss in gonadal function. The change can alter the states of phosphorylation on the proteins, which cause dramatic changes in the cellular location or activity of the proteins. In this study, the differential phosphorylation of the proteins responsible for the functions related to cognition was studied using the ovariectomized adult rats. Phosphoproteomic analysis using the cerebral and hippocampal tissues could identify 51 differentially phosphorylated proteins including 12 proteins for energy metabolism, 8 cytoskeletal proteins, 6 signaling proteins, and other functional proteins in the ovariectomized rats. Further, anti-oxidative enzymes, superoxide dismutase and peroxiredoxin-2, which are known to be inactivated by phosphorylation, were found to be differentially phosphorylated in the cerebellum and hippocampus of the ovariectomized rats, respectively. Many of the deactivated proteins by differential phosphorylation identified in this study were overlapped to those of Alzheimer's disease cases. These results will provide information for neurodegenerative learning and memory impairments in women as brought about by menopause.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1242-1251
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• 2016

The ethanol production of Trichoderma reesei was improved by genome shuffling in our previous work. Using RNA-Seq, the transcriptomes of T. reesei wild-type CICC40360 and recombinant strain HJ48 were compared under fermentation conditions. Based on this analysis, we defined a set of T. reesei genes involved in ethanol production. Further expression analysis identified a series of glycolysis enzymes, which are upregulated in the recombinant strain HJ48 under fermentation conditions. The differentially expressed genes were further validated by qPCR. The present study will be helpful for future studies on ethanol fermentation as well as the roles of the involved genes. This research reveals several major differences in metabolic pathways between recombinant strain HJ48 and wild-type CICC40360, which relates to the higher ethanol production on the former, and their further research could promote the development of techniques for increasing ethanol production.