• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.183-186
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• 2011

Biochemical methods were selected to evaluate the role of exopolymeric substances in the stability of biofilms used in bioremediation processes. Biofilms of Thiomonas arsenivorans formed on pozzolana were thus treated with pronase (protein target), lectins (Con A or PNA), calcofluor or periodic acid (polysaccharides target), DNase (DNA target), and lipase (triglycerides target). Neither protease nor DNase treatments had any effect on bacterial adhesion. Lectins and calcofluor treatments mainly affected young biofilms. Lipase treatment had a noticeable effect on biofilm stability whatever the biofilm age. Results suggest that it would be an increased resistance of mature biofilms that protects them from external attacks.

• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.187-191
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• 2011

Microbial fuel cells (MFCs) were successfully enriched using sludge contaminated with Cr(VI) and their characteristics were investigated. After enrichment, the charge of the final 10 peaks was 0.51 C ${\pm}$ 1.16%, and the anodic electrode was found to be covered with a biofilm. The enriched MFCs removed 93% of 5 mg/l Cr(VI) and 61% of 25 mg/l Cr(VI). 16S rDNA DGGE profiles from the anodic electrode indicated that ${\beta}$-Proteobacteria, Actinobacteria, and Acinetobacter sp. dominated. This study is the first to report that electrochemically active and Cr(VI)-reducing bacteria could be enriched in the anode compartment of MFCs using Cr(VI)-containing sludge and demonstrates the Cr(VI) removal capability of such MFCs.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.530-536
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• 2009

Cobalt chloride ($CoCl_2$) treatment of cells in vitro has been shown to induce cellular changes that are similar to those seen following hypoxia. To identify genes that are differentially expressed in response to treatment with $CoCl_2$, we compared the mRNA expression profiles of PC-3 cells that were treated with $CoCl_2$ with those of untreated PC-3 cells, using specific arbitrary primers and two anchored oligo(dT) primers provided in the ACP-based GeneFishing kits. The results of this study demonstrated that the puromycin-sensitive aminopeptidase (PSA) gene was down regulated in PC-3 cells that were treated with $CoCl_2$. This downregulation of PSA expression, in turn, suppressed the proliferation, migration, and invasion of PC-3 cells, as well as the secretion and expression of matrix metalloproteinase-9 (MMP-9).

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.491-494
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• 2009

Within the secondary metabolite class of flavonoids, which consist of more than 10,000 known structures, flavones define one of the largest subgroups. The diverse function of flavones in plants as well as their various roles in the interaction with other organisms offers many potential applications including in human nutrition and pharmacology. We used two genes, flavone synthase (PFNS-l) that converts naringenin into apigenin and flavone 7-O-methyltransferase (POMT-7) that converts apigenin into 7-O-methyl apigenin, to synthesize 7-O-methyl apigenenin from naringenin. The PFNS-l gene was subcloned into the E. coli expression vector pGEX and POMT-7 was subcloned into the pRSF vector. Since both constructs contain different replication origins and selection markers, they were cotransformed into E. coli. Using E. coli transformants harboring both PFNS-l and POMT-7, naringenin could be converted into 7-O-methyl apigenin, genkwanin.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.787-791
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• 2009

In the course of screening for substances that inhibit etoposide (10 ${\mu}g$/ml)-induced apoptosis in human leukemia U937 cells, fungal strain F000120, which exhibits potent inhibitory activity, was selected. The active compound was purified from an ethyl acetate extract of the microorganism by Sep-pak $C_{18}$ column chromatography and HPLC, and was identified as heptelidic acid (koningic acid) by spectroscopic methods. This compound inhibited caspase-3 induction in U937 cells with an $IC_{50}$ value of 40 ${\mu}M$ after 8 h of etoposide treatment. Fluorescent dye staining with acridine orange and ethidium bromide showed that heptelidic acid inhibited apoptosis. Furthermore, it was found that DNA fragmentation and caspase-3 activation, the biological hallmarks of apoptosis, were inhibited by the compound in a dose-dependent manner, suggesting that heptelidic acid inhibits etoposide-induced apoptosis via downregulation of caspases.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1103-1108
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• 2009

The human immunodeficiency virus (HIV)-l protein Tat acts as a transcription transactivator that stimulates expression of the infected viral genome. It is released from infected cells and can similarly affect neighboring cells. The nucleocapsid is an important protein that has a related significant role in early mRNA expression, and which contributes to the rapid viral replication that occurs during HIV-1 infection. To investigate the interaction between the Tat and nucleocapsid proteins, we utilized cDNA micro arrays using pTat and flag NC cotransfection in HEK 293T cells and reverse transcription-polymerase chain reaction to validate the micro array data. Four upregulated genes and nine downregulated genes were selected as candidate genes. Gene ontology analysis was conducted to define the biological process of the input genes. A proteomic approach using PathwayStudio determined the relationship between Tat and nucleocapsid; two automatically built pathways represented the interactions between the upregulated and downregulated genes. The results indicate that the up- and downregulated genes regulate HIV-1 replication and proliferation, and viral entry.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1135-1138
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• 2009

The bioassay-guided fractionation of MeOH extract from Naematoloma fasciculare afforded a petroleum ether fraction (NFPF) and four known compounds, which showed good antitumor activities to inhibit MCF-7 cell line proliferation in vitro and tumor growth in $H_{22}$ implanted mice in vivo. In addition, a number of unsaturated aliphatic acids were identified in NFPF by GC analysis. These results showed that NFPF inhibits tumor growth through the activity of unsaturated aliphatic acids together with two active compounds, ergosterol peroxide (1: 62.17 mg/g in NFPF) and ergosterol (2: 3.13 mg/g in NFPF), and indicate the potential utility of NFPF as an antitumor drug.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1150-1152
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• 2009

Geraniol (1) is the biogenetic precursor of a number of monoterpenes. We tested various marine-derived microorganisms to determine their ability to biotransform 1. Only Hypocrea sp. was capable of transforming 1 into its oxidized derivative, 1,7-dihydroxy-3,7-dimethyl-(E)-oct-2-ene (2). The structure of the metabolite obtained was assigned on the basis of detailed spectroscopic data analyses.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1006-1010
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• 2010

Pseudomonas putida JM37 metabolized glyoxylate at a specific rate of 55 g/g dry biomass/day. In order to investigate their role, three genes encoding enzymes that are potentially involved in the conversion of glyoxylate were disrupted; namely, tartronate semialdehyde synthase (gcl), malate synthase (glcB), and isocitrate lyase (aceA). Strains with transposon insertion in either of these genes were isolated from a 50,000 clone library employing a PCR-guided enrichment strategy. In addition, all three double mutants were constructed via targeted insertion of a knock-out plasmid. Neither mutation of gcl, glcB, and aceA nor any of the respective double mutations influenced glyoxylic acid conversion, indicating that P. putida JM37 may possess other enzymes and pathways for glyoxylate metabolism.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.985-987
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• 2010

The biological transformation of the bioactive dihydroisocoumarin, (-)-mellein, isolated from the marinederived fungus Cladosporium sp., was studied. The preparativescale culture of (-)-mellein with a marine isolate of a bacterium Stappia sp. resulted in the isolation of its oxidized metabolite, (3R,4S)-4-hydroxymellein. The stereostructure of the metabolite obtained was assigned on the basis of detailed physicochemical data analyses.