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1.
Int J Mol Sci ; 23(20)2022 Oct 19.
Article in English | MEDLINE | ID: mdl-36293392

ABSTRACT

Blood reflux and metabolic regulation play important roles in chronic venous disease (CVD) development. Histone deacetylases (HDACs) and DNA methyltransferases (DNMTs) serve as repressors that inhibit metabolic signaling, which is induced by proatherogenic flow to promote aortic endothelial cell (EC) dysfunction and atherosclerosis. The aim of this study was to elucidate the relationship between blood reflux and epigenetic factors HDACs and DNMTs in CVD. Human varicose veins with different levels of blood reflux versus normal veins with normal venous flow were examined. The results show that HDAC-1, -2, -3, -5, and -7 are overexpressed in the endothelium of varicose veins with blood reflux. Blood reflux-induced HDACs are enhanced in the varicose veins with a longer duration time of blood reflux. In contrast, these HDACs are rarely expressed in the endothelium of the normal vein with normal venous flow. Similar results are obtained for DNMT1 and DNMT3a. Our findings suggest that the epigenetic factors, HDACs and DNMTs, are induced in venous ECs in response to blood reflux but are inhibited in response to normal venous flow. Blood reflux-induced HDACs and DNMTs could inhibit metabolic regulation and promote venous EC dysfunction, which is highly correlated with CVD pathogenesis.


Subject(s)
Histone Deacetylases , Varicose Veins , Humans , Histone Deacetylases/genetics , Histone Deacetylases/metabolism , DNA Modification Methylases/genetics , Varicose Veins/genetics , Epigenesis, Genetic , DNA , Chronic Disease
2.
Cardiol Res Pract ; 2021: 1452917, 2021.
Article in English | MEDLINE | ID: mdl-34336268

ABSTRACT

BACKGROUND: MicroRNA-10a (miR-10a) inhibits transcriptional factor GATA6 to repress inflammatory GATA6/VCAM-1 signaling, which is regulated by blood flow to affect endothelial function/dysfunction. This study aimed to identify the expression patterns of miR-10a/GATA6/VCAM-1 in vivo and study their implications in the pathophysiology of human coronary artery disease (CAD), i.e., atherosclerosis. METHODS: Human atherosclerotic coronary arteries and nondiseased arteries were used to detect the expressions of miR-10a/GATA6/VCAM-1 in pathogenic vs. normal conditions. In addition, sera from CAD patients and healthy subjects were collected to detect the level of circulating miR-10a. RESULTS: The comparison of human atherosclerotic coronary arteries with nondiseased arteries demonstrated that lower levels of endothelial miR-10a are related to human atherogenesis. Moreover, GATA6/VCAM-1 (a downstream target of miR-10a) was highly expressed in the endothelium, accompanied by the reduced levels of miR-10a during the development of human atherosclerosis. In addition, CAD patients had a significantly lower concentration of miR-10a in their serum compared to healthy subjects. CONCLUSIONS: Our findings suggest that low miR-10a and high GATA6/VCAM-1 in the cardiovascular endothelium correlates to the development of human atherosclerotic lesions, suggesting that miR-10a signaling has the potential to be developed as a biomarker for human atherosclerosis.

3.
Biosensors (Basel) ; 11(1)2020 Dec 24.
Article in English | MEDLINE | ID: mdl-33374317

ABSTRACT

Coliform bacteria are indicators of water quality; however, most detection methods for coliform bacteria are time-consuming and nonspecific. Here, we developed a fluorescence in situ hybridization (FISH) approach to detect four types of coliform bacteria, including Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, and Citrobacter freundii, simultaneously in water samples using specific probes for 16S rRNA. This FISH method was applied to detect coliform bacteria in simulated water and domestic wastewater samples and compared with traditional detection methods (e.g., plate counting, multiple-tube fermentation (MTF) technique, and membrane filter (MF) technique). Optimal FISH conditions for detecting the four types of coliforms were found to be fixation in 3% paraformaldehyde at 4 °C for 2 h and hybridization at 50 °C for 1.5 h. By comparing FISH with plate counting, MTF, MF, and a commercial detection kit, we found that FISH had the shortest detection time and highest accuracy for the identification of coliform bacteria in simulated water and domestic wastewater samples. Moreover, the developed method could simultaneously detect individual species and concentrations of coliform bacteria. Overall, our findings indicated that FISH could be used as a rapid, accurate biosensor system for simultaneously detecting four types of coliform bacteria to ensure water safety.


Subject(s)
Bacteriological Techniques , Environmental Monitoring/methods , Water Microbiology , Escherichia coli/isolation & purification , Fluorescence , In Situ Hybridization, Fluorescence , RNA, Ribosomal, 16S
4.
Front Microbiol ; 10: 2436, 2019.
Article in English | MEDLINE | ID: mdl-31736888

ABSTRACT

Fumarate nitrate reduction regulator (FNR) is a direct oxygen-responsive transcriptional regulator containing an iron-sulfur (Fe-S) cluster. During anaerobic growth, the [4Fe-4S] cluster in FNR (holo-FNR) binds specifically to DNA, whereas exposure to oxygen results in the loss of its DNA-binding activity via oxidation of the [4Fe-4S] cluster. In this study, we aimed to investigate the role of FNR in regulation of capsular polysaccharide (CPS) biosynthesis, serum resistance, and anti-phagocytosis of K. pneumoniae. We found that the CPS amount in K. pneumoniae increased in anaerobic conditions, compared to that in aerobic conditions. An fnr deletion mutant and a site-directed mutant (fnr 3 CA), with the three cysteines (C20, C23, and C29) replaced with alanines to mimic an FNR lacking the [4Fe-4S] cluster, showed marked increase in CPS amount under anaerobic conditions. A promoter-reporter assay and qRT-PCR confirmed that the transcription of the cps genes was repressed by holo-FNR. In addition, we found that holo-FNR could repress the transcription of rmpA and rmpA2, encoding cps transcriptional activators. Deletion of rmpA or rmpA2 in the Δfnr strain reduced CPS biosynthesis, suggesting that RmpA and RmpA2 participated in the holo-FNR-mediated repression of cps transcription, thereby regulating the CPS amount, serum resistance, and anti-phagocytosis. Taken together, our results provided evidence that RmpA and RmpA2 participated in the holo-FNR-mediated repression of CPS biosynthesis, and resistance to the host defense in response to oxygen availability.

5.
J Biosci Bioeng ; 128(3): 274-282, 2019 Sep.
Article in English | MEDLINE | ID: mdl-30962101

ABSTRACT

Many genes of industrial relevance can be found in soil. In this study, metagenome sequencing of paddy soil was performed with 55.68 Gb sequences and 1,787,113 putative open reading frames (ORFs). The functional profiles and metabolic pathway of soil metagenomes were examined using Gene Ontology, Metagenomics RAST, and Kyoto Encyclopedia of Genes and Genomes. To verify the protein function and assembly of ORFs, a putative gene encoding α-galactosidase, namely GalR, which shares 65% identity with an unpublished glycoside hydrolase (GH) 27 family protein, was synthesized using its optimal codon for overexpression in Escherichia coli. GalR was successfully obtained and characterized. The optimal temperature and pH for GalR activity were 30°C and pH 9, respectively. Enzymatic activity indicated that GalR was alkaliphilic and different from acidophilic α-galactosidase in the GH 27 family. Furthermore, 50% of the relative activity of GalR can be attained for 1.7 and 0.7 h preincubation at 40°C and 50°C, respectively. Significant inhibition of GalR was observed in the presence of ethylenediaminetetraacetic acid (EDTA), MgCl2, sodium dodecyl sulfate (SDS), and H2O2; however, it was resistant to 0.1% methanol and ethanol and was slightly activated with NaCl and KCl. The specific activity of GalR was achieved at 11.6 and 0.59 µmol/min/mg of protein using p-nitrophenyl-α-d-galactopyranoside and raffinose as substrates, respectively. Consequently, the metagenomic sequencing-based strategy can provide information for mining novel genes.


Subject(s)
Genes, Synthetic , Metagenome , Metagenomics/methods , Soil/chemistry , alpha-Galactosidase/genetics , alpha-Galactosidase/isolation & purification , Cloning, Molecular , Escherichia coli/genetics , Galactose/metabolism , High-Throughput Nucleotide Sequencing/methods , Hydrogen Peroxide , Open Reading Frames , Raffinose/metabolism , Sesbania/genetics , Soil Microbiology , Trifolium/genetics
6.
J Biosci Bioeng ; 127(1): 59-65, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30097404

ABSTRACT

Asparagus cochinchinensis root (ACR) is used in traditional Chinese medicine. In this study, ACR was first extracted with 25% ethyl acetate (EA) and then fermented by Aspergillus oryzae to enhance its antioxidant activity and evaluate its potential antityrosinase activity. The physiological activity and cytotoxicity of A. oryzae-fermented ACR extract, along with its antityrosinase activity and effects on melanogenic factor levels in human epidermal melanocytes (HEMs), were analyzed and compared with those of the unfermented extract. The results showed that the physiological activity of the fermented extract in vitro or in cells was significantly higher than that of the unfermented extract. The IC50 values for 2,2-diphenyl-1-picrylhydrazine radical scavenging activity, reducing power, and antityrosinase activity in vitro for the fermented extract were 250.6 ± 32.5, 25.7 ± 3.5, and 50.6 ± 3.1 mg/L, respectively. The fermented extract favored cellular antityrosinase activity with low melanin production in human melanoma cells compared with the unfermented extract. The inhibitory mechanism of melanin synthesis by unfermented extract was independent of the tested melanogenesis-related proteins. However, the inhibitory mechanism of the fermented extract was possibly caused by synergistic inhibition of these proteins. Thus, A. oryzae-fermented ACR extract may be used for developing new health food or cosmetic ingredients.


Subject(s)
Antioxidants/pharmacology , Asparagaceae/chemistry , Aspergillus oryzae/metabolism , Fermentation/drug effects , Plant Extracts/pharmacology , Antioxidants/metabolism , Antioxidants/toxicity , Cells, Cultured , Humans , Infant, Newborn , Male , Melanins/biosynthesis , Monophenol Monooxygenase/metabolism , Plant Extracts/metabolism , Plant Extracts/toxicity , Toxicity Tests
7.
J Biosci Bioeng ; 127(4): 403-410, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30389327

ABSTRACT

Neoagaro-oligosaccharides prepared by agar hydrolysis have various application fields, including the pharmaceutical, cosmetic, and food industries. In this study, an agarolytic strain was isolated from a saltwater hot spring and identified as Microbulbifer pacificus LD25 by 16S rRNA. The whole genome sequence of M. pacificus LD25 was obtained. It had a size of 4.27 Mb and comprised 3062 predicted genes in 37 contigs with a G+C content of 58.0%. Six agarases were annotated and classified into three families, namely, GH16 (AgaL1), GH86 (AgaL2, AgaL3), and GH50 (AgaL4, AgaL5, AgaL6), which shared 75-96% identities with unpublished hypothetical proteins and agarases. AgaL1, AgaL4, and AgaL6 can be successfully expressed and purified in Escherichia coli. AgaL1 and AgaL4 displayed a significantly agarolytic capability, whereas AgaL6 exhibited a rarely detectable enzymatic activity. The optimal temperature and pH required for the activity of AgaL1 and AgaL4 was 50°C and 60°C, respectively, at pH 7. The specific activities of AgaL1 and AgaL4 were achieved at 16.8 and 9.6 U per mg of protein. Both agarases were significantly inhibited in the presence of EDTA, MgO, ZnCl2, and H2O2. However, AgaL1 was resistant to 0.1% SDS and AgaL4 was slightly activated by CaCl2. Substrate hydrolysis detected by LC-MS/MS analysis indicated that neoagarobiose was the main product during AgaL1 and AgaL4 catalysis. Furthermore, AgaL4 was thermostable and retained over 93% of its relative activity after pre-incubation at 70°C for 180 min. Consequently, M. pacificus LD25 has a potential for agarase production in E. coli and industrial applications.


Subject(s)
Alteromonadaceae/enzymology , Alteromonadaceae/genetics , Genome, Bacterial , Glycoside Hydrolases/genetics , Glycoside Hydrolases/metabolism , Hot Springs/microbiology , Alteromonadaceae/chemistry , Alteromonadaceae/metabolism , Base Sequence , Chromatography, Liquid , DNA, Bacterial/analysis , Disaccharides/metabolism , Enzyme Stability , Gene Expression Regulation, Bacterial , Gene Expression Regulation, Enzymologic , Glycoside Hydrolases/analysis , Glycoside Hydrolases/chemistry , Hydrolysis , RNA, Ribosomal, 16S/analysis , RNA, Ribosomal, 16S/genetics , Seawater/microbiology , Sequence Analysis, DNA , Tandem Mass Spectrometry
8.
Int J Med Mushrooms ; 20(9): 849-858, 2018.
Article in English | MEDLINE | ID: mdl-30317979

ABSTRACT

Taiwanofungus camphoratus is a unique medicinal mushroom endemic to Taiwan, and it is used as a folk medicine in East Asian countries. The aim of the present study was to investigate the immunomodulatory effects of "leader Antrodia cinnamomea capsule" (LAC), a health food product containing solid-state cultivated mycelial powder of T. camphoratus. For the in vivo studies, mice were orally administered LAC (76, 250, and 760 mg/kg b.w.) for 30 days, and its effects on cell-mediated humoral immune function were examined. The results of the concanavalin A-induced splenic lymphocyte proliferation test showed that LAC significantly increased splenic lymphocyte proliferation compared with the control. In addition, serum hemolysin analysis showed that LAC treatment significantly increased the half value of serum hemolysin (HC50) in mice compared with the control. Moreover, treatment with LAC significantly increased the phagocytic index as measured by carbon clearance and natural killer cell activity. Taken together, these findings provide strong evidence that LAC can modulate immune function.


Subject(s)
Basidiomycota/chemistry , Immunomodulation/drug effects , Animals , Dose-Response Relationship, Drug , Female , Functional Food , Killer Cells, Natural , Macrophages , Mice , Mice, Inbred BALB C , Random Allocation , Specific Pathogen-Free Organisms
9.
Front Microbiol ; 9: 2405, 2018.
Article in English | MEDLINE | ID: mdl-30369914

ABSTRACT

OmpR/EnvZ is a two-component system that senses osmotic signals and controls downstream gene expression in many species of Enterobacteriaceae. However, the role of OmpR/EnvZ in Klebsiella pneumoniae remains unknown. In this study, we found that production of MrkA, the major subunit of type 3 fimbriae, was decreased under hypertonic conditions. A deletion mutant of ompR and a site-directed mutant with a single amino acid substitution of aspartate 55 to alanine (D55A), which mimics the unphosphorylated form of OmpR, markedly reduced MrkA production under hypertonic conditions. These results indicate that K. pneumoniae type 3 fimbriae expression is activated by the phosphorylated form of OmpR (OmpR∼P). Although no typical OmpR∼P binding site was found in the P mrkA sequence, mrkA mRNA levels and P mrkA activity were decreased in the ΔompR and ompR D55A strains compared with the wild type (WT) strain, indicating that OmpR∼P mediates type 3 fimbriae expression at the transcriptional level. Previous reports have demonstrated that a cyclic-di-GMP (c-di-GMP) related gene cluster, mrkHIJ, regulates the expression of type 3 fimbriae. We found that both the ompR and ompR D55A mutants exhibited decreased mrkHIJ mRNA levels, intracellular c-di-GMP concentration, and bacterial biofilm amount, but increased total intracellular phosphodiesterase activity in response to hypertonic conditions. These results indicate that OmpR∼P regulates type 3 fimbriae expression to influence K. pneumoniae biofilm formation via MrkHIJ and modulation of intracellular c-di-GMP levels. Taken together, we herein provide evidence that OmpR∼P acts as a critical factor in the regulation of the c-di-GMP signaling pathway, type 3 fimbriae expression, and biofilm amount in K. pneumoniae in response to osmotic stresses.

10.
J Nat Med ; 69(4): 513-21, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25951809

ABSTRACT

Antrodia cinnamomea is a valuable and unique edible fungus originating from the forests of Taiwan. In this study, an anti-metastatic compound, 2,3,5-trimethoxy-4-cresol (TMC), was isolated from the solid-state cultured mycelium of A. cinnamomea. According to the results obtained from cell wound healing, cell migration and invasion assays, TMC effectively suppressed movement, migration and invasion of lung cancer cells at the dosage of 5-40 µM, which was non-toxic to A549 cells. In addition, TMC reduced protein expression of Akt, MMP-2 and MMP-9 and enhanced E-cadherin and TIMP-1 protein expression, which are known to regulate cell adhesion, migration and invasion. Taken together, TMC effectively suppresses movement, migration and invasion of lung cancer cells, and achieves an anti-cancer metastasis effect.


Subject(s)
Antrodia/chemistry , Carcinoma, Non-Small-Cell Lung/drug therapy , Lung Neoplasms/drug therapy , Mycelium/chemistry , Plants, Medicinal/chemistry , Carcinoma, Non-Small-Cell Lung/mortality , Epithelial-Mesenchymal Transition , Humans , Lung Neoplasms/mortality
11.
Chemosphere ; 92(6): 695-701, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23664476

ABSTRACT

The efficiency of a coupled photocatalytic-biological system for removing crystal violet (CV) from an aqueous solution was assessed. Initial experiments demonstrated that the optimal operating parameters for the photoreactor were a 1.5-h reaction time, pH 7.0, and a 2.0-min retention time. Under these conditions, the photocatalytic reaction reduced the toxicity of the CV solution by 94%. Subsequent evaluation of the performance and characteristics of the coupled photocatalytic-biological system in terms of CV removal revealed that the coupled system successfully removed and efficiently mineralized CV in a semi-continuous mode when the CV concentration was <150mgL(-1). Based on our analysis of the degradation products, CV degradation in this coupled system involved stepwise demethylation and aromatic ring opening. Phylogenetic analysis of the bioreactor effluent showed that the predominant phyla were Proteobacteria, followed by Bacteroidetes and Actinobacteria, suggesting that this coupled system is conducive for such processes as demethylation, aromatic ring opening, carbon oxidation, and nitrification. These results were verified in a GC-MS analysis. To our knowledge, this is the first report on CV removal using a coupled system.


Subject(s)
Gentian Violet/isolation & purification , Wastewater/analysis , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Actinobacteria/genetics , Actinobacteria/isolation & purification , Bacteroidetes/genetics , Bacteroidetes/isolation & purification , Biodegradation, Environmental , Bioreactors/microbiology , Catalysis , Photolysis , Phylogeny , Proteobacteria/genetics , Proteobacteria/isolation & purification
12.
Environ Technol ; 34(1-4): 313-20, 2013.
Article in English | MEDLINE | ID: mdl-23530345

ABSTRACT

The use of matured compost as an inoculation agent to improve the composting of vegetable and fruit wastes in a laboratory-scale composter was evaluated, and the commercial feasibility of this approach in a pilot-scale (1.8 x 10(4) L) composter was subsequently confirmed. The effect of aeration rate on the physico-chemical and biological properties of compost was also studied. Aeration rate affected the fermentation temperature, moisture content, pH, O2 consumption rate, CO2 production rate and the formation of odour. The optimal aeration rate was 2.5 L air/kg dry solid/min. The CO2 production rate approached the theoretical value during composting and was linearly dependent on temperature, indicating that the compost system had good operating characteristics. The inoculation of cellulolytic bacteria and deodorizing bacteria to compost in the pilot-scale composter led to an 18.2% volatile solids loss and a 64.3% volume reduction ratio in 52 h; only 1.5 ppm(v) odour was detected. This is the first study to focus on both operating performance and odour removal in a pilot-scale composter.


Subject(s)
Garbage , Odorants , Soil Microbiology , Soil/analysis , Air , Carbon/analysis , Carbon Dioxide/analysis , Feasibility Studies , Fruit , Hydrogen-Ion Concentration , Nitrates/analysis , Nitrogen/analysis , Oxygen Consumption , Temperature , Vegetables , Water/analysis
13.
Article in English | MEDLINE | ID: mdl-20390863

ABSTRACT

To shorten the time needed to measure biochemical oxygen demand (BOD) in water samples and to provide a rapid feedback of the real condition of water quality, we tested and evaluated the validity and reliability of luminescent bacteria Vibrio fischeri, Photobacterium phosphoreum, and recombinant Escherichia coli as potential indicators of BOD in the domestic wastewaters. The results indicate that the luminescence intensities of these strains are dependent on temperature, pH, and BOD concentration. In comparison to the standard BOD(5) method, the time needed for BOD measurement can be shortened by 90, 120, and 150 min when V. fischeri, P. phosphoreum, and recombinant E. coli, respectively, are used. Recombinant E. coli can be adapted to measure BOD in domestic wastewater containing a wide range of BOD concentrations, V. fischeri is not suitable for measuring diluted wastewater, and P. phosphoreum has only a limited application in measuring concentrated wastewater. To the best of our knowledge, this is the first report in which V. fischeri, P. phosphoreum, and recombinant luminescent E. coli are compared in terms of their potential in BOD measurement systems.


Subject(s)
Aliivibrio fischeri/metabolism , Escherichia coli/metabolism , Oxygen/metabolism , Photobacterium/metabolism , Recombination, Genetic , Calibration , Hydrogen-Ion Concentration , Luminescence , Temperature
14.
J Ind Microbiol Biotechnol ; 37(3): 237-44, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19936813

ABSTRACT

Methods to detect the presence of coliform bacteria in drinking water usually involve a series of complex cultivating steps that are time-consuming and subject to external influences. For this reason, the new 16S rRNA probe has been developed in this study as an alternative detector PCR-ELISA technique that does not involve the culture of bacteria and that is able to detect, identify, and quantify the representative coliform species present in water samples. Our results indicate that this technique is both rapid (detection time of 4 h) and accurate (1.4% error rate). The limit of detection (LOD) was 5 CFU/100 ml for total coliforms, which meets the standards set by most countries for drinking water. Our comparative study demonstrated that this PCR-ELISA method is superior to current conventional methods in terms of detection time, LOD, and accuracy.


Subject(s)
Bacteriological Techniques , Enterobacteriaceae/isolation & purification , Enzyme-Linked Immunosorbent Assay/methods , Polymerase Chain Reaction/methods , Water Microbiology , Colony Count, Microbial/methods , Diagnostic Errors/statistics & numerical data , Oligonucleotide Probes/genetics , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sensitivity and Specificity , Time Factors
15.
J Hazard Mater ; 172(2-3): 1439-45, 2009 Dec 30.
Article in English | MEDLINE | ID: mdl-19717235

ABSTRACT

In our study, we have isolated a relatively newly identified bacteria species, Pandoraea pulmonicola YC32, and first assessed its capability to treat malachite green (MG). The effects of various factors on decolorization efficiency were investigated in a batch system. The decolorization efficiency was found to be optimal within a pH of 7-10 and it increased, with increasing initial MG concentration up to 100 mg/l. The relationship between the decolorization rate and MG concentration agreed with Lineweaver-Burk equation. The apparent kinetic parameters, R(MG,max) and K(m), were 6.23 mg-MG/g-cell/h and 153.4 mg/l, respectively. The initial step in the biodegradation pathway of MG by P. pulmonicola YC32 was a reduction or N-demethylation reaction. We achieved a decolorization efficiency of 85.2% with 50mg/l MG in the immobilized P. pulmonicola YC32 continuous column system. This is the first report on the application of a continuous column system to decolorize MG using a microorganism.


Subject(s)
Biodegradation, Environmental , Coloring Agents/metabolism , Gram-Negative Bacteria/metabolism , Rosaniline Dyes/metabolism , Hydrogen-Ion Concentration , Kinetics
16.
Bioresour Technol ; 99(16): 7487-94, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18359225

ABSTRACT

The removal of arsenic (As) species, such as As(III) and As(V), from water by molybdate-impregnated chitosan beads (MICB) in both batch and continuous operations was studied. The effects of pH, temperature, coexisting ions, and arsenic concentrations were studied in batch tests. Studies on the kinetic adsorption of MICB, the recovery of arsenic by the desorption solution, and the reuse of MICB were also carried out. The practicality and efficiency of an MCIB-packed column on arsenic removal were evaluated in a continuous system on industrial arsenic-containing wastewater discharged during the manufacture of GaAs supports. The results indicate that MICB favor the adsorption of both As(V) and As(III). The optimal pH value for As(III) and As(V) removal was 5. The adsorption of arsenic on the MICB is most likely an exothermic reaction. The effect of coexisting ions was varied and depended on their concentrations and species. The optimal desorption solution for arsenic recovery was 1M H2SO4, which resulted in a 95% efficiency for As(III) and 99% for As(V). In the continuous tests, the MICB-packed column exhibited excellent arsenic removal from wastewater without any pretreatment. These results provide strong evidence of the potential of MICB for removing As from industrial wastewaters.


Subject(s)
Arsenic/analysis , Chitosan/chemistry , Molybdenum/chemistry , Online Systems , Water Pollutants, Chemical/analysis , Water Purification/methods , Adsorption , Hydrogen-Ion Concentration , Temperature
17.
FEBS Lett ; 553(3): 397-402, 2003 Oct 23.
Article in English | MEDLINE | ID: mdl-14572658

ABSTRACT

In contrast to the ribosomal RNA gene expression increasing with growth rate, transcription of the lac operon is downregulated by cell growth rate. In continuous culture, growth rate regulation of lac promoter was independent of carbon substrate used and its location on the chromosome. Since the lac operon is activated by cyclic adenosine monophosphate (cAMP), which decreases with increasing cell growth rate, expression of plac-lacZ reporter fusion was analyzed in cya mutant under various growth conditions. The results demonstrated that expression of plac-lacZ in cya mutant was both lower and growth rate independent. In addition, ppGpp (guanosine tetraphosphate) was not involved in the mechanism of growth rate regulation of the lac promoter. Thus, the results of this study indicate that cAMP mediates the growth rate-dependent regulation of lac operon expression in Escherichia coli.


Subject(s)
Cyclic AMP/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Lac Operon/physiology , Bacteriophages/genetics , Bacteriophages/growth & development , Bacteriophages/metabolism , Carbon/metabolism , Cyclic AMP Receptor Protein/genetics , Escherichia coli/growth & development , Gene Deletion , Gene Expression Regulation/genetics , Genotype , Guanosine Tetraphosphate/metabolism , Mutation , Phenotype , Plasmids/genetics , Species Specificity , Transcription, Genetic , beta-Galactosidase/metabolism
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