• The Plant Pathology Journal
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• v.22 no.2
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• pp.139-146
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• 2006

The 3' region of Potato virus X (PVX) has the 74 nt 3'-nontranslated region (NTR) that is conserved among all potexviruses and contains several cis-acting elements for minus-strand and plus-strand RNA accumulation. Three stem-loop structures (SL1-SL3), especially formation of SL3 and U-rich sequence of SL2, and near upstream elements in the 3' NTR were previously demonstrated as important cis-acting elements. To Investigate the binding of these cis-acting elements within 3' end with host protein, we used the electrophoretic mobility shift assays (EMSA) and UV-cross linking analysis. The EMSA with cellular extracts from tobacco and RNA transcripts corresponding to the 150 nt of the 3' end of PVX RNA showed that the 3' end of PVX formed complexes with cellular proteins. The specificity of protein binding was confirmed through competition assay by using with 50-fold excess of specific and non-specific probes. We also conducted EMSA with RNAs containing various mutants on those cis-acting elements (${\Delta}10$10, SL3B, SL2A and ${\Delta}21$; J Mol Biol 326, 701-720) required for efficient PVX RNA accumulation. These analyses supported that these cis-acting elements are required for interaction with host protein(s). UV-cross linking analysis revealed that at least three major host proteins of about 28, 32, and 42 kDa in mass bound to these cis-elements. These results indicate that cis-acting elements from 3' end which are important for minus and plus-strand RNA accumulation are also required for host protein binding.

• Biomolecules & Therapeutics
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• v.11 no.2
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• pp.139-144
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• 2003

Ganoderma lucidum is commonly known as medically potent mushroom, which has been widely used in China and other oriental countries for the treatment of various diseases, including cancer. In this report, we investigated the anti-oxidant and protective effect of Ganodema lucidum extract (GLE) against the DNA damage induced by free radical and U.V. In the assay of cell growth inhibition, the inhibitory cell growth rate induced by hydroxyl radical was dose-dependently decreased by GLE. This results support that GLE has a detoxifying activity against cytotoxicity of hydroxyl radical in E. coli cell. GLE also protected ColE1 plasmid DNA damage in the concentration of 200$\mu\textrm{g}$ per reaction on the DNA fragmentation assay. The nuclear tailing by hydrogen peroxide in single cell gel electrophoresis(SCGE) was decreased by GLE in the concentration of 50$\mu\textrm{g}$/ml. These data indicate that Ganoderma lucidum has an anti-oxidative activity to hydrogen peroxide. The mutation rate after irradiation of U.V. was reduced by 50$\mu\textrm{g}$/ml GLE and total number of Rif (Rifampicin) resistant mutants was decreased in a concentration dependent manner when added the GLE exogenously in a culture media. According to the results, it is likely that GLE has not only an anti-oxidative activity to hydroxyl radical but also an anti-mutagenic activity to U.V. mutagenesis.

• The Korean Journal of Mycology
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• v.21 no.4
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• pp.323-331
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• 1993

The protoplast formation and intergeneric protoplast fusion between Gliocladium virens and Trichoderma harzianum were attempted to obtain fusants. Protoplast formation was the most effective when the strains were treated with concentration of 5 mg/ml of Novozyme 234 and Cellulase at $25^{\circ}C$ for 3 hours in phosphate buffer, pH 6.5, supplemented with 0.6 M sorbitol as osmotic stabilizer. Auxotrophic mutants of G. virens G88 did not grow in minimal medium and benomyl resistant T. harzianum T95 from wild types, however, was selected by treatment with UV light as genetic marker to isolate fusants. When the intergeneric protoplast fusion between G. virens G88 and T. harzianum T95 was carried out using 30% PEG 4000 containing 10 mM $CaCl_{2}$, and 50 mM glycine (pH 8.5) as fusogenic agent at $25^{\circ}C$ for 10-15 min, the fusion frequency was $0.8{\times}10^{-4}$. Fusants obtained from intergeneric protoplast fusion were spontaneously segregated into va rious strains by continous culture on complete medium. Several intergeneric hybrids were classified into three types: parent-like hybrids, segregants, and recombinants.

• The Microorganisms and Industry
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• v.19 no.4
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• pp.27-31
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• 1993

Certain bacterial species possess the capability of differentiation through several morphogenetic changes which enable them to adapt to certain internal and external stimuli(Losick and Shapiro 1984). Upon induction, cells of A. vinelandii undergo a morphological process which leads to the production of one cyst per cell (Sadoff, 1975). The cysts are considerably resistant to desiccation, which confers a survival advantages upon the organism(Socolofsky and Wyss 1962). Like other prokaryotic differentiations encystment provides a relatively simple model of cellular differentiation. Like in other differentiating bacteria, vegetative growth can be separated from differentiation. Furthermore, the differentiation cycle can be synchronized by specific inducer. There have been a great deal of morphological and physiological studies on this process. However, the mechanisms used to regulate cell differentiation can be clearly defined by careful genetic analysis of the process. Unfortunately, A. vinelandii has proven to be difficult for genetic analysis (Sadoff 1975). For example, it has been shown that a variety of metabolic mutants of Azotobacter speicies are difficult to isolate after mutagenesis with chemical mutagens or UV irradiation. Nevertheless recent advances in molecular genetics in Azotobacter species, especially in the nitrogen fixation research area, appear to be able to overcome this difficulty (Robinson et al. 1986; Kennedy et al. 1986).

• Molecules and Cells
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• v.20 no.2
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• pp.228-234
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• 2005

Caenorhabditis elegans him-6 mutants, which show a high incidence of males and partial embryonic lethality, are defective in the orthologue of human Bloom's syndrome protein (BLM). When strain him-6(e1104) containing a missense him-6 mutation was irradiated with ${\gamma}$-rays during germ cell development or embryogenesis, embryonic lethality was higher than in the wild type, suggesting a critical function of the wild type gene in mitotic and pachytene stage germ cells as well as in early embryos. Even in the absence of ${\gamma}$-irradiation, apoptosis was elevated in the germ cells of the him-6 strain and this increase was dependent on a functional p53 homologue (CEP-1), suggesting that spontaneous DNA damage accumulates due to him-6 deficiency. However, induction of germline apoptosis by ionizing radiation was not significantly affected by the deficiency, indicating that HIM-6 has no role in the induction of apoptosis by exogenous DNA damage. We conclude that the C. elegans BLM orthologue is involved in DNA repair in promeiotic cells undergoing homologous recombination, as well as in actively dividing germline and somatic cells.

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.271-277
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• 1986

A sisomicin-producing strain, Micromonospora inyoensis, was treated with various mutagens. The optimal death rates to obtain the high-producers of sisomicin were 90% for ultraviolet light, 99% for nitrosoguanidine, and 99.3% for nitrous acid, respectively. In place of the method of liquid culture, an agar plug method, which is easy and convenient, was used to measure the antibiotic-producing abilities of the strains isolated from mutagen-treated cells. On the other hand, as the selection method of overproducing mutants after mutagenesis, gradient agar plates which included various antibiotics and salts were used. Among the antibiotics and salts tested, gentamicin and kanamycin as antibiotics, and CuCl$_2$ and HgCl$_2$ as salts, were effective to select the high-producers of sisomicin.

• The Korean Journal of Mycology
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• v.19 no.1
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• pp.27-31
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• 1991

Formation of conidium, an asexual organ on the hyphae, was examined from ten species of Pleurotus. Conidiospores of them were distinguished into two types of spores; an elliptical and a globose spores. Dikaryotic hyphae of ten species and monokaryotic hyphae of three species were observed to produce conidiospore. Conidia were observed on the hyphae grown on mushroom complete agar medium but were not on mushroom minimal agar medium. Two aconidial mutants were obtained by the ultraviolet irradiation.

• Journal of Plant Biology
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• v.39 no.4
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• pp.243-247
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• 1996

Phosphoribosylanthranilate transferase (PAT) catalyzes the second step of the tryptophan biosynthetic pathway and is encoded by a single-copy gene that complements all the visible phenotypes of the tryptophan mutant (trp1-100) of Arabidopsis. The trp1-100 is blue fluorescent under UV light becuase it accumulates anthranilate. To obtain a plant with reduced PAT activity, PAT1 genes with several internal deletions in different promoter regions (pHS 101, pHS102, pHS104, pHS105, and pHS107) were induced into trp1-100 via Agrobacterium. Then, homozygous T3 plants were isolated and examined for blue fluorescence. Introduction of the PAT1 gene fusants results in the reversion of fluorescence phenotype except in the case of pHS105. These results prompted us to perform a parallel analysis of anthranilate synthase and PAT interms of the genetic complementation. A plant line carrying pHS105 gene fusant does not completely complement the blue fluorescence but it accumulates less anthranilate than trp1-100. The activity of PAT was reduced in the transgenic mutant as well. The plant carrying these constructs will add to the growing collection of molecular tools for the study of the indolic secondary metabolism.

• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.119-125
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• 1979

As the first step of domestic developmint of the nucleic acid-related compounds, purine base required auxotrophs from Brevibacterium ammoniagenes ATCC 6872 were derived by the ultraviolet irradiation or the treatment of N-methyl-N'-nitro-N-nitroso guanidine (NTG), diethyl sulfate (DES), and ethylme-thyl sulfate (EMS). The optimum conditions of mutation by means of several mutagens were induced respectively. The yield of mutants was 0.083％ by the ultraviolet irradiation, 0.67％ by the NTG treatment, 1.1％ by the DES treatment, and 0.45％ by the EMS treatment. Six strains among 239 auxotrophs were screened out to accumulate 5'-lMP in the culture broth. Cry-stalline 5'-lMP was isolated from the culture broth of Brevifbacterium ammoniagenes adnine-guanine less mutant D-21530 by the use of anion exchange resin, Amberlite IRA-402, and it was identified physically and chemically as 5'-inosinic acid.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1115-1119
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• 2001

Eight Escherichia coli cells with aerobic growth deflects were isolated by the insertion of ${\lambda}placMu53$, a hybrid bacteriophage of ${\lambda}$ and Mu, which created transcriptional fusion to lacZY. Two of these mutants, CLIO and CLl2, were irradiated with UV to obtain specialized transducing phages. The phages that took out the neighboring chromosomal DNA of the related gene responsible for deflective aerobic growth were identified. The in vivo cloned chromosomal sequence revealed that the mutated gene of CLIO was located at min 34.5 on the Escherichia coli linkage map and 1,599,515 on the physical map. The physical map indicated that there were 7 cistrons in the operon. We named this operon oxg10. The promoter sequence of oxg10 exhibited a possible binding site far SoxS, a transcriptional regulator that activates the transcription of various SoxRS regulon genes. Transferring the oxg10:: ${\lambda}placMu53$ mutation into the wild-type strain, RZ4500, resulted in the inhibition of normal aerobic growth, while the salute mutation in strain MO inhibited aerobic cell growth completely. The full operon sequences of oxg10 were cloned from the Excherichia coli genomic library. The mutated gene of CLl2 was identified to be a sucA gene encoding the ${\alpha}$-ketoglutarate dehydrogenase El component in the TCA cycle.