• 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.

• 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.

• 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.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.359-363
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• 1995

The antigenic variation of B. thuringiensis subsp. satto have been investigated for 120 hours during sporulation and crystallization by using SDS-PAGE and Western blot. Most antigens of a vegetative cell were found to disappear as it was in sporulation and crystallization, but protein antigens of 46, 29, 27, and 21 kDa continued to be expressed. The new protein bands of 293, 138, 119, 75, and 68 kDa appeared on days 2 through 5 in modified GYS medium. They were thought to be involved in sporulation and crystallization. The protein of 138 kDa was found to be a major protein of both crystal and spore. The expression patterns were immunologically analyzed by Western blot. The polyclonal antisera against the intact crystal showed strong immunoreactivity to proteins with molecular masses of 293, 138, 68, and 46 kDa. The polyclonal antisera against the spore recognized proteins of 293, 138, 68, and 46 kDa. Both crystals and spores appeared to express the common protein antigens.

• Journal of Microbiology
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• v.37 no.1
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• pp.27-34
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• 1999

Two fractions with unusual antifungal activity that suppress asexual sporulation of several fungi were obtained from culture filtrate of Pseudomonas aeruginosa and were partially purified through the repeated silicagel flash column chromatographies. The sporulation-suppressive actions of these fractions in Aspergillus nidulans, Rhizopus stolonifer, and Coprinus cinereus, were analyzed by light and electron microscopes. The germination ability of the spores produced in the presence of these fractions were also checked to determine the persistent effects of these antifungal substances on the next generation. Light microscopic observation of developing sporangia of R. stolonifer grown in the presence of both fractions revealed that the significant number of sporangia failed to reach maturity, and frequently, uncontrolled growths of hyphae and rhizoids from the sporangiophores were found. In A. nidulans addition of these fractions appeared to cause different classes of morphological abnormality in conidia development, which included aborted formation of conidiogenous cells from the apex of conidiophores and enhanced hyphal growths either at the tip or middle of the conidiophores. Germination abilities of spores obtained from the cultures grown in the presence of antifungal fractions were 40∼60% in Aspergillus, 50∼80% in Coprinus (thallic spores), and 30∼40% in Rhizopus compared to those of normal spores.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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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

• 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.

• The Korean Journal of Mycology
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• v.18 no.2
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• pp.109-114
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• 1990

The effect of different carbon and nitrogen compounds on the growth and sporula­tion of Curvularia clavata Alcorn (Herberium No. IMI264075) has been studied. All the carbon sources tried were well utilized by the pathogen though glucose, and sucrose supported the best growth while glucose, maltose and sucrose the sporulation of the fungus. Of the nine nitrogen compounds, L-glutamic acid supported the best growth while aspartic acid and L-glutamic acid the sporulation of the fungus. Growth and sporulation were generally better with organic than inorganic nitrogen sources. Ammonium sulphate was the best inorganic source. A sudden drop of pH value of the culture media after 4 days of incubation did not favour good growth of the fungus.

• Parasites, Hosts and Diseases
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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.

• 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 $t_7\;or\;t_8$.