• Title, Summary, Keyword: sporulation

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Novel strategy for isolating suppressors of meiosis-deficient mutants and its application for isolating the bcy1 suppressor

  • Shin, Deug-Yong;Yun, Jean-Ho;Yoo, Hyang-Sook
    • Journal of Microbiology
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    • v.35 no.1
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    • pp.61-65
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    • 1997
  • A novel strategy was developed for isolating suppressors from sporulation-deficient mutants. The mutation in the BCY1 gene, which codes for the regulatory subunit of cAMP-dependent protein kinase, when homozygous, results in diploids being meiosis and sporulation deficient. Two plasmids, YCp-MAT.alpha. and YEp-SPOT7-lacZ, were introduced into MAT.alpha. BCY1$\^$+/ or MAT.alpha. bcy1 haploid cells. The transformant of the BCY1$\^$+/ haploid cell produced .betha.-galactosidase under nutrient starvation, but the bcy1 transformant did not. Using this system, the mutagenesis experiment performed on the bcy1 transformant strain resulted in a number of sporulation mutants that produced .betha.-galactosidase under nutrient starvation. One complementation group, sob1, was identified from the isoalted suppressor mutants and characterized as a single recessive mutation by tetrad analysis. Genetic analysis revealed that the sob1 mutation suppressed the sporulation deficiency, the failure to arrest at the G1 phase of the cell cecle, and the sensitivity to heat or nitrogen starvation caused by the bcy1 mutation. However, the sob1 mutation did not suppress the sporulation deficiency of ime1 and of ime2 diploids. These results suggest that the sob1 mutation affects a gene which functions as a downstream regulator in both meiosis and cell cycle regulation.

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Suppressive Activities of Foliar Spray Fungicides for Apple Against Sporulation of Botryosphaeria dothidea, the Causal Fungus of White Rot, and Their Role in Disease Control (사과 경엽 살포용 살균제의 겹무늬썩음병균에 대한 포자형성 억제작용과 그것이 병 방제에 미치는 영향)

  • Lee, Dong-Hyuk;Cho, Lae-Hong;Shin, Jung-Sup;Uhm, Jae-Youl
    • Research in Plant Disease
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    • v.12 no.3
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    • pp.240-248
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    • 2006
  • Control of white rot which is one of the most serious apple diseases in Korea has mainly relied on periodical spray of protective fungicides. As the main inoculum source of the disease is pycnidiospores produced in the warts formed on affected stems of apple tree, it can be conceivable that inhibition of spore production might be an effective means for controlling the disease. Inhibitory efficacy of eight selected fungicides against sporulation of the fungus was assessed by counting the number of spores produced at detached warts treated with the fungicides of recommended dilution. They showed diverse effect on sporulation. Carbendazim and azoxystrobin suppressed sporulation almost completely, the former irreversively. Thiram and folpet promoted sporulation as producing much more number of spores than untreated control. Others showed almost no effect on sporulation. Effects of suppression and promotion in the sporulation shown by the fungicides on the control of white rot were examined by incidences of disease and infection at the plots adopted the spray programs of which the fungicide at late May was substituted by carbendazim, azoxystrobin, folpet and thiram, respectively. Disease incidence and infection frequency at the plots sprayed former two chemicals which suppressed sporulation were much lower than those of the plots adopted latter two chemicals and untreated plot at which the fungicide spray was skipped at that time. These facts were reconfirmed in the experiments conducted with carbendazim and thiram, in which 100 fruits were bagged just prior to each spray from late May to late July for elucidating the effect of the two fungicides on the action of subsequent ones. Disease incidence and infection frequency on the fruit bagged just prior to each spray were gradually increased as the seasons going on. The increase rate at the carbendazim plot was much lower than that of thiram. Especially, the fruit infected till late July at the carbendazim plot were almost completely cured by the three fungicides, iminoctadine-triacetate, tebuconazole and samzinwang, a combined formular of iminoctadine-triacetate and difenoconazole, sprayed at late July and hence. In thiram plot, infected fruit were also cured by the 3 fungicides but not remarkable. From these results, it can be concluded that control efficiency of white rot can be greatly enhanced by selecting the fungicide capable of suppress the sporulation of white rot fungus at the season when the mass dispersal of spores is not initiated.

Sugar and Amino Acid Transport in Yeast I. Glucose Transport during the Sporulation Stage with Reference to the Vegetative Stage. (효모세포의 당과 아미노산의 운반에 관한 연구 -I. 생장시기와 포자형성기의 포도당 운반-)

  • 민경희;권영명
    • Korean Journal of Microbiology
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    • v.16 no.3
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    • pp.122-130
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    • 1978
  • During the sporulation stage in Saccharomyces cerevisiae J170, the incorporation of $D^{14}$ C-glucose into starved cells of sporulation stage as well as the vegetative one is appeared higher at pH 6.0. Glucose transport system, in both the vegetative and sporulation stage, is associated with "energy dependent" as the result of repression by such a respiratory inhibitor as 2, 4-dinitrophenol. The Km value of glucose uptake in vegetative stage and sporulation stage was 2.1 mM and 2.5 mM respectively, indicating that the glucose is considerably reuqired for vegetative growth. Competition and countertranspoer of glucose by frutose and galactose are more distinct in vegetative stage, comparing with sporulation stage. The main sugar components of yeast cells consists of ribose, mannose, and ${\alpha}, \;{\beta}-glucose$. Amounts of mannose is lower in the aporulation stage than that in the vegetative stage.

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Factors Affecting Sporulation of a Mycoherbicide, Epicoccosorus nematosporus, on the Lesion of Eleocharis kuroguwai

  • Hong, Yeon-Kyu;Hyun, Jong-Nae;Cho, Jae-Min;Uhm, Jae-Youl;Kim, Soon-Chul
    • The Plant Pathology Journal
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    • v.18 no.2
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    • pp.81-84
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    • 2002
  • Effects of temperature and dew period on sporulation of a mycoherbicide, Epicoccosorus nematosporus, on the lesion of its host, Eleocharis kuroguwai were determined. Conidia formation was first observed after 10 days on plants incubated for either 12 or 16 h in a dew chamber at 28$^{\circ}C$; 16 h dew period resulted in more conidia formation. As the dew period was decreased to less than 8 h, fewer conidia formed. Conidial production was most abundant at 28$^{\circ}C$ and produced as much as 3.3$\times$10$^4$conidia per lesion, while 0.1$\times$10$^3$and 2.3$\times$10$^3$conidia per lesion were produced at 16$^{\circ}C$ and 36$^{\circ}C$, respectively. Alternating temperature regimes, i.e., 30/15, 30/20, 28/20, and 28/15$^{\circ}C$ (day/night) were much better than constant temperature, i.e., 30/30, 28/28/, and 20/2$0^{\circ}C$ for sporulation. In the second sporulation, there were as much as 3.1$\times$10$^4$conidia per lesion (ca. <50% of the first sporulation). Then, sporulation dropped sharply to 6.2$\times$10$^2$conidia per lesion in the third sporulation. Results of this study suggest that temperature combined with dew period is the primary limiting factor in the use of E. nematosporus as a mycoherbicide off, kuroguwai.

Physiological and Nutritional Factors for Efficient Sporulation and Toxin Formation in Bacillus tthuringiensis

  • 이은희;반재구;김정일
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • pp.522.2-522
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    • 1986
  • In order to optimally induce sporulation and toxin formation in Bacillus thuringiensis, exhaustion of specific nutrients as well as resuspension experiments were tried. Sporulation and toxin formation was most abunduntly occurred when the growth was limited by carbon source. It was also occurred in a resuspension medium containing only distilled water. Various environmental and physiological factors affecting the efficiencies of spore and toxin formation were examined in chemically defined media. As a result of these studies, a batch fermentation resulted in higher spore and toxin yield than ever reported

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Susceptibility of Bacillus subtilis SNU816 to bacteriophage SP816 during growth and sporulation. (성장 및 포자형성 중인 Bacillus subtilis SNU816의 SP816 박테리오파아지에 대한 감수성에 관하여)

  • Lee, Oh-hyoung;Lee, Zoo-Shik
    • Korean Journal of Microbiology
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    • v.22 no.2
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    • pp.111-118
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    • 1984
  • The changes of susceptibility of Bacillus subtilis SNU816 to bacteriophage SP816 were investigated. When B. sutilis SNU816 cells were infected by the phage during vegetative growth, rapid lysis was observed. But when they were infected after late logarismic phase, they were resistant to phage infection. Since asporogenic culture of this strain was invariably lysed regardless of time of infection, the arrest of phage multiplication seemed to be caused by sporulation. In reality, the arrest of phage multiplication occurred at early stage of sporulation. Electron microscopy revealed that the arrest of phage multiplication occurred just prior to or during septum formation (stage II sporulation).

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Effects of ammonia water on sporulation of coccidial oocysts originated from bovine (암모니아수(水) 처리가 소콕시디아 오시스트 포자형성(胞子形成)에 미치는 영향(影響))

  • Wee, Sung-hwan;Kang, Yung-bai;Jang, Hwan;Lee, Hee-su;Choi, Sang-ho
    • Korean Journal of Veterinary Research
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    • v.30 no.1
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    • pp.103-106
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    • 1990
  • Effects of ammonia water on the spornlation of coccidial oocysts collected from bovine feces were studied with particular reference to the various levels of ammonia water (1% to 10%) for 30 minute conservation at room temperature. The sporulation rates showed a negative linear coorelation according to the treatment leavels of ammonia water, 85.3% at 1% level to 8.9% at 10% level. The optimum level of ammonia concentration was regarded as 5% to 10% with more than 80% of sporulation inhibition effect.

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Increased Heat Resistance of Geobacillus stearothermophilus Spores Heat-Shocked During Sporulation

  • Lee Sang-Wook;Sim Sang-Jun
    • Journal of Microbiology and Biotechnology
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    • v.16 no.4
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    • pp.633-636
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    • 2006
  • The purpose of this study was to measure the heat resistance and core mineral content of Geobacillus stearothermophilus ATCC 7953 spores when the sporulating cells were exposed to heat shock at different times during sporulation. Heat shock during sporulation was found to increase the heat resistance of the spores produced subsequently. The spores heat shocked 2 h after the end of the exponential phase showed the highest heat resistance and a 3D-fold increase in the $d_{10}$ compared with the non-heat-shocked spores. The enhanced heat resistance was likely due to the increased mineral content observed in the spores heat shocked at $t_7\;or\;t_8$.

Suppression of Eimeria tenella Sporulation by Disinfectants

  • You, Myung-Jo
    • The Korean Journal of Parasitology
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    • v.52 no.4
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    • pp.435-438
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    • 2014
  • The disinfectant effects (DEs) of 10 types of chemicals, defined by their ability to destroy or inhibit oocysts and consequently prevent sporulation of Eimeria tenella field isolate, were evaluated in vitro. Correct species assignments and sample purities were confirmed by the singular internal transcribed spacer (ITS)-PCR analysis. A total of 18 treatments were performed, and the disinfection suppression levels were 75.9% for 39% benzene + 22% xylene (1:10 dilution), 85.5% for 30% cresol soup (1:1 dilution), and 91.7% for 99.9% acetic acid (1:2 dilution) group. The results indicate that acetic acid, cresol soup, and benzene+xylene are good candidates for suppression of E. tenella oocyst sporulation.

On the Mitochmria of Yeast and M-DNA (효모의 미토콘드리아와 M-DNA)

  • 홍순우
    • Korean Journal of Microbiology
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    • v.9 no.1
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    • pp.39-45
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    • 1971
  • During the sporulation stage in Saccharomyces cerevisiae J170, the incorporation of D$^{14}$ C-glucose into starved cells of sporulation stage as well as the vegetative one is appeared higher at pH 6.0. Glucose transport system, in both the vegetative and sporulation stage, is associated with "energy dependent" as the result of repression by such a respiratory inhibitor as 2,4-dinitrophenol. The Km value of glucose uptake in vegetative stage and sporulation stage was 2.1 mM and 2.5 mM respectively, indicating that the glucose is considerably reuqired for vegetative growth. Competition and countertranspoer of glucose by frutose and galactose are more distinct in vegetative stage, comparing with sporulation stage. The main sugar components of yeast cells consists of ribose, mannose, and .apha., .betha.-glucose. Amounts of mannose is lower in the aporulation stage than that in the vegetative stage.ive stage.

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