• 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.

• ALGAE
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• 제18권4호
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• pp.355-360
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• 2003

A Gram (-), rod-shaped bacterium in size of 1.6-2.8 $\times$ 0.4 μm was isolated from a eutrophic reservoir, which exhibited growth-inhibiting effect against a bluegreen alga (Anabaena cylindrica). This isolate showed positive reactions for catalase and oxidase, and optimal conditions of 35-40°C and pH 9.0. This isolate was designated AC-1 in this manuscript. In a mixed-culture of A. cylindrica and AC-1, their growth patterns were inversely correlated and the bluegreen algal vegetative cells completely disappeared within 24-36 hours. AC-1 showed similar lytic activity in natural water as in an artificial medium. The lytic activity of AC-1 was dependent on the photosynthetic activity of A. cylindrica. When observed under phase contrast microscope, the isolate lysed vegetative cells of A. cylindrica in scattered state in a liquid medium, whereas heterocysts have not been lysed.

• 한국균학회지
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• 제22권4호
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• pp.281-285
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• 1994

Phytophthora cactorum으로부터 분리된 유주자(遊走子)는 균사 생장이 상대적으로 균일하고 균사 생장분포가 모체(母體) 균주(菌株)와 유사하였으나, 분리된 난포자(卵胞子)는 균사생장분포가 매우 다양하였다. 또한, 균총의 특징은 난포자에서 크게 다양한 반면, 유주자에서는 균일하였다. 이 결과는 P. cactorum의 균사생장과 균총의 모양을 결정하는데 있어 다양한 유전자가 관여하고 있으며, 몇몇 역병균이 생장하는 동안에 이배체성 생식을 나타낼 수 있다는 점을 시사한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.370-375
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• 1998

Spectral reflectance signatures of upland crops at OSMI bands were collected and evaluated for the feasibility of crop discrimination knowledge-based on crop calendar. Effective bands and their ratio values for discriminating corn from two other legumes were defined with OSMI equivalent bands and their ratio values. June 22 among measurements dates was the best date for corn discrimination from two other legumes, peanut and soybean, because all OSMI equivalent bands and their ratio values in June 22 were highly significant for corn separability. Phenological growth stage of a silage corn (rs510) could be estimated as a function of spectral reflectance signatures in vegetative stage. Five growth stage prediction models were generated by the SAS procedures REG and STEPWISE with OSMI equivalent bands and their ratio values in vegetative stage.

• Journal of Plant Biology
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• 제26권3호
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• pp.131-139
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• 1983

Temperature response of amoebae of thermotactic mutants have been investigated. Amoebae of the mutant strain HO 428 showed positive thermotaxs which is strong at lower temperaturs and drops sharply above the growth temperature of amoebae. The temperature response of HO 428 amoebae was not affected by the length of amoebae on the grdients. HO 596 amoebae seemed to have both positive and negative thermotactic responses shortly after food depletion. Longer exposure of these amoebae on the thermal gradients induced a stronger negative response at lower temperatures and an apparent positive response at higher temperatures. A similar changes could be observed in HO 1445 amoebae. Based on the steady positive thermotactic response by HO 428 amoebae and the mode of change in termperature response at higher temperatures, 24$^{\circ}C$ and $25^{\circ}C$, by HO 596 amoebae, a model for the temperature response of vegetative Dictyostelium discoideum amoebae, strain HL 50, has been proposed. The main features of the model are: a positive response at the thermal gradients with midpoint temperatures lower than the growth temperatures of amoebae and a negative response above it.

• 한국환경과학회지
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• 제12권6호
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• pp.659-664
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• 2003

The experiment was carried out to investigate the effects of sulfuric acid and nitric acid among the main components of simulated acid rain (SAR) on the growth of vegetative organs and seed germination of Arabidopsis thaliana. The Arabidopsis treated with SAR supplemented with sulfuric and nitric acids, respectively, showed 28% and 30% decrease of shoot and root growth compared to the control plants, and also many necrotic spots on leaf surfaces after SAR treatment were observed. The shoot and root length for plants grown with nitric acid rain was 14% and 17% lower, respectively, compared to the control, whereas those grown with sulfuric acid rain was 24% and 25% lower than control plants. When Arabidopsis seeds were sown in distilled water, germination rate was 100% after 7 days. However, 80% in SAR medium supplemented with sulfuric and nitric acids, 88% in sulfuric acid rain medium and 93% in nitric acid rain medium. The germination abilities of seeds harvested from SAR supplemented with sulfuric and nitric acids, sulfuric acid rain, and nitric acid rain were 73%, 73% and 94%, respectively. Consequently, sulfuric acids showed more inhibitory effects than nitric acids on the growth of vegetative organs as well as germination rates in Arabidopsis.

• Journal of Microbiology and Biotechnology
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• 제16권1호
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• pp.5-14
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• 2006

Streptomycetes are Gram-positive microorganisms producing secondary metabolites through unique physiological differentiation [4]. The microbes show unusual morphological differentiation to form substrate mycelia, aerial mycelia, and arthrospores on solid medium [19]. Substrate mycelium growth is sustaining with sufficient nutrients in the culture medium. The concentration of a specific individual substrate in the culture environment is the most important extracellular factor allowing vegetative mycelia growth, where extracellular hydrolytic enzymes participate in the utilization of waterinsoluble substrates. However, with starvation of nutrients in the culture medium, the vegetative mycelia differentiate to aerial mycelia and spores. It has been considered that shiftdown of essential nutrients for mycelia growth is the most important factor triggering morphological and physiological differentiation in Streptomyces spp. Since proteineous macromolecule compounds are the major cellular components, these are faced to endogenously metabolize following a severe depletion of nitrogen source in culture nutrients (Fig. 1). Various proteases were identified of which production was specifically related with the phase of mycelium growth and also morphological differentiation. The involvement of proteases and protease inhibitor is reviewed as a factor explaining the mycelium differentiation in Streptomyces spp.

• 아시안잔디학회지
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• 제5권1호
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• pp.23-32
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• 1991

The purpose of this study was to determine the vegetative growth of two cool season turfgrasses during summer season in Korea. Ten respective cultivars of Kentucky bluegrass [Poapratensis L.] and perennial ryegrass [Lolium perenne L.] were exposed to unshaded, 30% and 60% shade for 4odays. First mowing height was 7cm, and then clippings were harvested every ten days at the same height. Shading increased the total length of clippings of all cultivars of two turfgrasses, but fresh and dry weight were significantly decreased. The highest shoot length obtained at 30% shade in Kentucky bluegrass and at 60% shade in perennial ryegrass. 'Rugky', 'Sydsport', 'Wabash' and 'Baron' of Kentucky bluegrass and 'Repel', 'Omega II', 'Ovation', 'Linn', 'Bell' and 'Manhattan' of perennial ryegrass showed relatively high tolerance to shade. Especially, in 'Citation II' perennial ryegrass, fresh and dry weight were increased by 30% shade. The number of tillers generally decreased with increasing shade. In 30% shade, 'Midnight' Kentucky bluegrass and 'Omega II' perennial ryegrass were least reduced and 'Baron' Kentucky bluegrass and 'Pennant' perennial ryegrass were most reduced. The cultivars of lower growth habit in full sunlight showed shade tolerance compared to those of higher growth habit.

• Journal of Ecology and Environment
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• 제41권10호
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• pp.281-289
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• 2017

Background: In this study, the growth and reproductive response of seedlings, grown in plastic pots with sand, to moisture and nutrients were analyzed in order to study the environmental conditions required to create an alternative habitat for Epilobium hirsutum L., an endangered plant. Results: Vegetative and reproductive growths of Epilobium hirsutum L. are accelerated with increase in moisture and organic matter content in the soil. Among vegetative organs, the number of runners related to asexual reproduction was the highest when the moisture content was over 25% and nutrient content between 7 and 14% in the soil. But the number of flowers related to flowering responses, among reproductive organs, was the highest when the moisture content was maintained at 75% and when nutrient content was 21% in the soil. The number of seeds, related to sexual reproduction, was the highest when the moisture content was over 25% and nutrient content between 14 and 21%. Conclusions: The study results show that a place with high moisture and nutrient content in the soil is advantageous to asexual and sexual reproduction of Epilobium hirsutum L. Therefore, we must serve periodically nutrient and seeds to sustain population in in situ conservation. Furthermore, it is advisable to create in riverside where abundant nutrient content have, making alternative habitat of Epilobium hirsutum L. Also, we must find species that have high contribution degree index through vegetation survey.

• 한국작물학회지
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• 제28권2호
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• pp.151-163
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• 1983

우리나라의 주요 수도 신품종 및 도입 품종을 공시하여 출수생태에 대한 기초자료를 얻고자 일장을 10, 12, 14 및 16시간의 4수준으로 하여 기본영양생장성과 감광성을 검토하였던 바 그 결과를 요약하면 다음과 같다. 1. 출수일수는 일장이 10, 12, 14 및 16시간으로 길어짐에 따라 지연되었는데 그 정도는 14 및 16시간에서 더욱 뚜렷하였다. 2. 일장에 따른 각 품종의 출수일수를 기초로 하여 일장반응형을 분류하면 7개의 group으로 구분할 수 있었는데, I-IV group은 대부분 일본형 품종이고, V-Ⅶ group은 모두 통일형 품종이었다. 3. 일본형 품종은 기본영양생장성이 짧고 감광성이 예민하였으며 통일형 품종은 기본영양생장성이 길고 감광성이 순한 경향이었다. 4. 일본형의 육성품종과 도입품종간에는 감광성과 기본영양생장성의 유의차는 없었다. 5. 조ㆍ중ㆍ만생종의 기본영양생장성과 감광성의 정도는 조생종의 경우 기본영양생장성 정도에서 일본형이 짧고 통일형은 뚜렷이 길었으며 감광성 정도는 일본형 및 통일형 품종 공히 순한 경향이었다. 한편 중ㆍ만생종의 경우 기본영양생장성 정도는 조생종과 비슷하였으나 감광성 정도는 일본형이 예민하고 통일형 품종이 순하였다. 6. 기본영양생장성과 감광성의 고저에 따른 각 품종들의 출수생태형은 19개 생태형으로 구분되었다. 7. 생태형중 대부부의 일본형 품종은 I-V, I-Ⅵ, II-IV, II-V 및 II-Ⅵ에, 통일형 품종은 Ⅵ-II, IV-III, V-II, V-III, Ⅵ-I, Ⅵ-II 및 Ⅶ-I에 속하였다.