• Molecules and Cells
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• 제20권1호
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• pp.119-126
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• 2005

${\alpha}$-Expansins are bound to the cell wall of plants and can be solubilized with an extraction buffer containing 1 M NaCl. Localization of ${\alpha}$-expansins in the cell wall was confirmed by immunogold labeling and electron microscopy. The subcellular localization of vegetative ${\beta}$-expansins has not yet been studied. Using antibodies specific for OsEXPB3, a vegetative ${\beta}$-expansin of rice (Oryza sativa L.), we found that OsEXPB3 is tightly bound to the cell wall and, unlike ${\alpha}$-expansins, cannot be solubilized with extraction buffer containing 1 M NaCl. OsEXPB3 protein could only be extracted with buffer containing SDS. The subcellular localization of the OsEXPB3 protein was confirmed by immunogold labeling and electron microscopy. Gold particles were mainly distributed over the primary cell walls. Immunohistochemistry showed that OsEXPB3 is present in all regions of the coleoptile and root tissues tested.

• 한국미생물·생명공학회지
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• 제21권3호
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• pp.200-206
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• 1993

The effect of pH (7, 5 and 4) and nisin (100 and 200IU/ml) on heat resistance of Listeria monocytogenes Scott A were determined using citrate-phosphate buffer system. Heat resistance of vegetative and starved cell was decreased as pH value was lower at 65 and 72C. Starved L. monocytogenes was more resistant than vegetative cell at both temperature. Heat resistance of vegetative and starved cell was decreased significantly with treatment of nisin. The effect of nisin was increased significantly at low pH(5, 4). Adherent microcolony was more resistant to heat and nisin than planktonic cell. Contamination of L. monocytogenes may be prevent by using nisin in food and food processing environments.

• Membrane and Water Treatment
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• 제15권1호
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• pp.11-19
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• 2024

This study presents the characteristics of growth and morphology of Anabaena sp., a representative filamentous cyanobacterium, depending on temperature variation from 10 to 30 ℃. Both the filament density (or number) and its length of Anabaena were highly affected by temperature, as well as growth stage. Rapid growth at a higher temperature led to an increase in Anabaena filament density, as well as optical density at 680 nm (OD₆₈₀). However, the number of vegetative cells within a single filament of Anabaena grown at 30 ℃ was smaller than those grown at lower temperatures, due to the intercalary division of the filament. Of the three different cells comprising a single Anabaena filament, the vegetative cell marginally affects the growth of Anabaena. The main dimensions of the vegetative cell, i.e., length and width, depend on the temperature and growth stage. The length-to-width (L/W) ratios of vegetative cells and akinetes were relatively consistent regardless of the temperature. However, in vegetative cells with dichotomous growth, the L/W ratio shows clear differences depending on their growth stage. It has been demonstrated that the L/W ratio could be used as an indicator to indirectly predict the growth stage of on-sit Anabaena samples.

• Preventive Nutrition and Food Science
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• 제12권4호
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• pp.259-266
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• 2007

It has been proposed that the mode of action of nisin against vegetative cells and spores of Clostridium botulinum is different. However, clear explanation is not available. Therefore, nisin action against vegetative cells and spores of C. botulinum was investigated in this study. Nisin was added at various stages of spore-to-vegetative cell transition and changes to sensitivity to the bacteriocin were observed. Different nisin preparation (Nisaplin or pure nisin) was compared for their activity against different stages of spore transformation of C. botulinum ATCC 25763. Germination was measured by determining loss of heat resistance and observing phase darkening of spores under phase-contrast microscope. Nisin acted bactericidally against vegetative cells, but acted sporostatically against spores of C. botulinum under the same concentration. This bactericidal and sporostatic action of nisin was dependent on the concentration of nisin used. Presence of nisin during spore activation by heat increased subsequent phase darkening and germination rates. However, nisin inhibited the germination and the outgrowth, when it was added after heat activation stage. Findings from this study suggest that the time of addition of nisin is very important for the effective control of spores during the heating process of foods. In addition, it may be possible to apply nisin at the stage of processing that coincides with the most sensitive stage of spore transformation.

• 한국미생물·생명공학회지
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• 제21권2호
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• pp.176-180
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• 1993

Survival and heat resistance of Listeria monocytogenes Scott A in various nutritional environments and cell type on stainless steel were determined. Viable cell of L. monocytogenes Scott A was most rapidly decreased in phosphate buffer among various media such as NSM (30 g TSB/1 l D.W.), LNM (2 g TSB/1 l D.W.) and phosphate buffer (pH=7) during incubation at 21 and 35C but survived for 15 days at 21C. Vegetative and starved L. monocytogenes Scott A were survived after heat treatment for 5 min at 65C while not detected at 72C.

• 환경생물
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• 제35권4호
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• pp.501-514
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• 2017

시스트와 영양세포의 유연성을 파악하기 위해 발아실험을 실시하였다. 발아실험 결과 총 25종에서 발아가 이루어져 시스트와 영양세포와의 관계를 확인하였다. 가막만에서 우점종으로 출현하지만 영양세포로 출현이 제한적인 Protoperidinium americanum이 발아실험 결과 확인되었고, Protoperidinium oblongum의 시스트로 알려진 Votadinium carvum은 발아실험 결과 세 가지 형태의 시스트에서 각기 다른 영양세포가 출현하여, 유전자 분석 등을 통한 정확한 종 동정이 요구되었다. 또한 Cochlodinium polykrikoides의 시스트라고 알려진 종은 발아실험 결과 C. polykrikoides의 시스트가 아닌 Cochlodinium sp.인 것으로 판명되었고 C. polykrikoides의 시스트는 출현하지 않았다.

• Journal of Veterinary Science
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• 제22권1호
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• pp.11.1-11.7
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• 2021

Background: The spore-forming bacterium Bacillus anthracis causes anthrax, an often-fatal infection in animals. Therefore, a rapid and reliable strategy to decontaminate areas, humans, and livestock from B. anthracis is very critical. Objectives: The aim of this study was performed to evaluate the efficacy of sodium hypochlorite, calcium hypochlorite, and quaternary ammonium compound (QAC) sanitizers, which are commonly used in the food industry, to inhibit spores and vegetative cells of B. anthracis surrogate. Methods: We evaluated the efficacy of sodium hypochlorite, calcium hypochlorite, and a QAC in inhibiting vegetative cells and spores of a B. anthracis surrogate. We treated a 0.1-mL vegetative cell culture or spore solution with 10 mL sanitizer. The samples were serially diluted and cultured. Results: We found that 50 ppm sodium hypochlorite (pH 7), 1 ppm calcium hypochlorite, and 1 ppm QAC completely eliminated the cells in vegetative state. Exposure to 3,000 ppm sodium hypochlorite (pH 7) and 300 ppm calcium hypochlorite significantly eliminated the bacterial spores; however, 50,000 ppm QAC could not eliminate all spores. Conclusions: Calcium hypochlorite and QAC showed better performance than sodium hypochlorite in completely eliminating vegetative cells of B. anthracis surrogate. QAC was ineffective against spores of the B. anthracis surrogate. Among the three commercial disinfectants tested, calcium hypochlorite most effectively eliminated both B. anthracis vegetative cells and spores.

• ALGAE
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• 제24권2호
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• pp.85-91
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• 2009

The filamentous cyanobacterium Anabaena sp. Strain PCC 7120 produces a developmental patten of single hete- rocysts separated by approximately 10 vegetative cells. Heterocysts differentiate from vegetative cells and are spe- cialized for nitrogen fixation. The patS gene, which encodes a small peptide that inhibits heterocyst differentiation, is expressed in proheterocysts and plays a critical role in establishing the heterocyst pattem. Another key regulator of heterocyst development is the hetR gene. hetR mutants fail to produce heterocysts and extra copies of hetR on a plas- mid cause a multiple contiguous heterocyst phenotype. To elucidate the relationship between these two counter act- ing factors in the genetic regulatory pathway during heterocyst differentiation, the expression patterns of a patS-gfp and a hetR-gfp fusion were examined in a patS deletion and a hetR deletion strain. The results, in combination with the result from a hetR and patS double deletion strain, suggest patS and hetR are mutually antagonistic and the bal- ance between these two factors in tow different cell types (heterocysts and vegetative cells) may be critical during the decision making process on their cell fates.

• 생명과학회지
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• 제2권4호
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• pp.232-239
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• 1992

UDP_GlcNAc is metabolized to form vegetative cell wall, cortical peptidoglycans, and outermost layer consisting of galactosamine-6-phosphate ploysaccharide in life cycle of Bacillus megaterium. To obtain a better understanding of the UDP-GlcNAc regulation, we examined the activity of the common first enzyme for the synthesis of nucleotide precursors of peptidoglycans, enoylpyruvate transferase by newly developed method. Both the specific and the total activity decreased after the end of exponential growth followed by and increase from t5 but decreased again parallel to the appearance of the activity of UDP_GlcNAc-4-epimerase. Antibody specificity to anti-transferase IgG and the elution profile on DEAE-Sepharose revealed that B. megaterium has at least two enoylpyruvate transferase isozymes, and UDP_GlcNAc was metabolized to vegetative cell wall and cortical peptidoglycan by each isozme in exponential growth and in sporulation, respectively in life cycle.

• Journal of Plant Biology
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• 제36권3호
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• pp.241-249
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• 1993

The pattern of RNA synthesis during male gametogenesis of Brassica napus was studied using 3H-uridine autoradiography. No incorporation of isotope occurred in the newly released microspore and the nonvacuolate, furrowed microspore. Peak incorporation of label during male gametogenesis occurred in the uninucleate, furrowed microspores showing various degrees of vacuolation. In this microspore stage, silver grains were localized in the nucleus and cytoplasm. Moderate incorporation of the isotope occurred in the nulceus of the vacuolated microspore. After the microspore mitosis, isotope incorporation occurred predominantly in the nucleus of the vegetative cell with little or no incorporation in the generative cell. In tricellular pollen, no incorporation of isotope was observed in both the vegetative nucleus and the sperms. Silver grains almost completely disappeared from tricellular mature pollen grains ready to germinate.