• 한국식물병리학회지
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• 제14권5호
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• pp.445-451
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• 1998

A severe Phytophthora rot of strawberry caused by a species of Phytophthora has been widely occurred at major cultivation areas of Kimhae on August in 1997. Incidence of the disease was obtained in the range of 69.2~83.6% in surveyed 4 fields and showed an average of 75.2%. A species of Phytophthora was mostly isolated from the crown of infected strawberry plants and all the isolates were identified as P. nicotianae var. nicotianae (=P. parasitica). The fungus showed strong pathogenicity on strawberry by inoculation test. As a result of the leaf inoculation using mycelial disks of the fungus, both leaves and petioles were darkly browned, and were finally blighted. As a result of the root inoculation of zoospore suspension, both roots and crowns were rotten with dark brown. Although the fungus produced sporangia either on V-8 juice agar medium or liquid medium, the sporangia observed on the liquid medium appeared to be broadly turbinate and noncaducous. Moreover the fungus cultured on the liquid medium often produced sporangia having two papilla. The number of zoospores in sporangia was found to be ranged from 3 or 4 to as many as 20 or 25. In addition, the released zoospore from the sporangium became the cystospore during the prolonged culture of the fungus. The sporangia were measured as av. 49$\times$35 ${\mu}{\textrm}{m}$ with l/b ratio of 1.43. All isolates from crowns were heterothallic and A1 mating type since oospores were abundantly formed on clarified V-8 juice agar by dual culture with P. capsici A2 mating type. Aplerotic oospores were sized 24-26 ${\mu}{\textrm}{m}$. Antheridia were always amphigynous and recoreded an average of 12$\times$10 ${\mu}{\textrm}{m}$. Hyphal swlling were easily observed, and terminal or intercalary chlamydospores were abundantly formed on V-8 juice agar as well as in C/Z solution and sized av. 28.2 ${\mu}{\textrm}{m}$. This is the first report of Phytophthora rot of strawberry in Korea.

• 식물병연구
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• 제16권2호
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• pp.158-162
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• 2010

하남성지역의 고추역병 발병포장 건전한 고추뿌리와 근권토양에서 세균 507균주를 분리하였는데, 그중에서 고추역병균에 길항효과가 우수한 G28-6, G28-5, I7-6과 H14-1균주를 선발하였다. In vitro에서 선발된 균주들은 고추역병균의 균사생장, 유주자낭과 유주자 형성, 그리고 피낭포자의 발아를 현저하게 억제하였고, Pot시험에서 선발된 균주 모두 70% 이상의 방제효과를 나타냈고, 포트시험에서 방제효과가 우수하였던 G28-6균주는 고추역병 자연발생 비닐하우스에서 79.4%의 방제가를 보여 공시된 화학농약 80% Mancozeb 보다 훨씬 높은 방제효과를 보였다. 뿐만 아니라 선발된 4균주 모두 in vitro에서 우수한 근권정착능력을 보였다. 고추역병 방제에 우수한 길항세균으로 선발된 G28-6균주의 16S rRNA gene 염기서열분석과 그의 형태적, 생리적 특성들을 Bergey's manual of Systematic Bacteriology를 기준으로 비교하여 Pseudomonas aurantiaca로 동정하였다.

• 식물조직배양학회지
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• 제26권3호
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• pp.177-182
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• 1999

Chitinase 유전자가 삽입된 감자 Belchip 품종의 형질전환체와 대조구에 곰팡이 병원균을 접종하였다. 7개 계통의 형질전환식물체를 12cm정도 키운 후 병원균인 Phytophthora infestans의 zoospore를 접종하여 인공적으로 역병을 유발시켰다. 그 결과 발병율에 따라서 세 그룹으로 분리되었는데 대조구에 비하여 감염 정도가 심한 것 2개 계통. 비슷한 3개 계통, 발병 정도가 약한 2개 계통으로 구분되었다. 대조구에 비하여 저항성이 높았던 2개 계통과 발병이 심했던 1개 계통만을 대상으로 하여 2차실험을 실시한 결과, 1차실험과 비슷한 경향을 나타냈다. 포장에서 생육된 2개의 저항성 계통은 자연적으로 발생한 역병에 대해서도 역시 대조구에 비하여 역병저항성이 더 높았다.

• 한국동물위생학회지
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• 제34권1호
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• pp.55-61
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• 2011

Dermatopathologic findings on cutaneous streptothricosis (bovine dermatophilosis) were conducted in Dinajpur of Bangladesh for one year. The animals were examined clinically at hospital during the physical visit of the affected animals and clinical manifestations and patients' history were recorded. The gross lesions were systematically examined, noted and categorized. An impression smear was made by the skin scraps, stained with Gram's stain and examined microscopically for the presence of causative bacteria. The suitable sizes of skins of 3 animals typically affected with dermatophilosis were collected surgically from the animals, and prepared for the histopathological study. The cardinal clinical features and gross lesions were characterized as paint-brush cutaneous surface with matted hairs, scab and crust formation, roughened coat; istopathologically as hyperkeratosis, parakeratosis, typical "palisading encrustations", extensive proliferation of coccoid shaped, bluish coloured bacteria (zoospores) in the cells of the outer rootsheath of the hair follicles, separation of keratinized layer from the epidermal epithelium, epidermal hyperplasia, densely cellular dermis with moderate destruction of glandular structures. Coccoid shaped gram positive organisms which form multidimensional arrangement were also observed by impression smear. The clinical signs, gross lesions, morphology of the organisms, staining properties, and histopathological features of the affected skin were diagnostic criteria for the bovine cutaneous streptothricosis.

• 한국수산과학회지
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• 제40권5호
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• pp.315-322
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• 2007

Kjellmaniella crassifalia Miyabe is one of the valuable seaweed crops cultured in the Korean coastal waters of the East Sea. Unfortunately recent environmental changes have adversely influenced its growth, prompting the need to develop techniques for species restoration. To obtatin biological information, the growth of the species was monitored for one year. The maximum blade length, $110{\pm}45cm$, was attained in July, and zoospores were released in November. The optimum culture conditions allowing juvenile sporophytes to grow to young blades consisted of $20{\mu}mol/m^2s\;at\;10^{\circ}C$ under which the blade length grew to $1,732.5{\pm}143.3{\mu}m$ in 42 days. Sporangial sori started to form in September, reaching 85% maturity in November and 89% maturity in December. Examining the growth of the species according to depth, the individuals growing at 5 meters grew the most, reaching a blade length of $75.9{\pm}18.9cm$ in August.

• 환경생물
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• 제31권4호
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• pp.347-352
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• 2013

감태의 인공채묘시 유주자 및 유리배우체를 채묘하여 양성 생장도를 비교하므로써, 유리배우체의 대량양식 이용 가능성을 시험하였다. 2008년 11월에 유주자 및 유리배우체를 채묘한 채묘틀을 이용하여 2009년 5월부터 10월까지 전남 완도군 약산면 시험어장에서 양성 생장도를 비교하였다. 유주자 및 유리배우체 채묘 실험구에서 감태 엽체의 엽장과 생체량 등은 유의한 차이를 보이지 않았다.

• The Plant Pathology Journal
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• 제36권3호
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• pp.244-254
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• 2020

Gom-chwi (Ligularia fischeri) is severely infected with Phytophthora drechsleri, the causal organism of Phytophthora root rot, an economically important crop disease that needs management throughout the cultivation period. In the present study, Phytophthora root rot was controlled by using bacterial isolates from rhizosphere soils collected from various plants and screened for antagonistic activity against P. drechsleri. A total of 172 bacterial strains were isolated, of which, 49 strains showed antagonistic activities by dual culture assay. In the seedling assay, six out of the 49 strains showed a predominant effect on suppressing P. drechsleri. Among the six strains, the ObRS-5 strain showed remarkable against P. drechsleri when treated with seed dipping or soil drenching. The ObRS-5 strain was identified as Enterobacter asburiae based on 16S ribosomal RNA gene sequences analysis. The bacterial cells of E. asburiae ObRS-5 significantly suppressed sporangium formation and zoospore germination in P. drechsleri by 87.4% and 66.7%, respectively. In addition, culture filtrate of E. asburiae ObRS-5 also significantly inhibited sporangium formation and zoospore germination by 97.0% and 67.6%, respectively. Soil drenched bacterial cells, filtrate, and culture solution of E. asburiae ObRS-5 effectively suppressed Phytophthora root rot by 63.2%, 57.9%, and 81.1%, respectively. Thus, E. asburiae ObRS-5 could be used as a potential agent for the biological control of Phytophthora root rot infecting gom-chwi.

• The Plant Pathology Journal
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• 제36권6호
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• pp.600-607
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• 2020

Phytophthora capsici Leonian is a major pathogen of pepper worldwide and few resistance sources to this pathogen have been identified so far. The goals of this study were to identify new sources of resistance against P. capsici in Capsicum landraces and analyze the relationship between the resistance indicator of plant symptoms and some plant phenotype parameters of plant height, stem width, leaf length and leaf width. Thirty-two landraces of pepper were collected from fourteen states in Mexico. From each population, 36 plants were inoculated with 10,000 zoospores of P. capsici under controlled conditions. This experiment was repeated twice. Out of the 32 landraces, six showed high level of resistance, four showed intermediate resistance and five showed low level of resistance when compared with the susceptible control 'Bravo' and the resistant control 'CM334', indicating that these landraces are promising novel sources of resistance to P. capsici. There was no correlation between the symptoms and plant phenotype parameters. However, these parameters were not affected in the group classified as highly resistant, indicating that P. capsici does not affect the growing of these resistant pepper landraces. The other resistant groups were significantly affected in a differently manner regarding their phenotype, indicating that this pathogen reduce their growth in different ways. This study reports novel resistance sources with great potential that could be used in breeding programs to develop new pepper cultivars with durable resistance to P. capsici.

• 한국패류학회지
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• 제26권3호
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• pp.211-215
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• 2010

퍼킨서스편모충 P. olseni는 우리나라 바지락의 대부분이 감염되어 있으며 극심한 염증을 유발하는 우리나라 바지락의 대표적 기생충이다. 본 연구에서는 퍼킨서스편모충의 생태학적 특성을 조사하고자 영양체에서 휴면포자로 전환되는 과정과 유주자를 형성하는 과정에서 수온과 염분이 미치는 영향을 조사하였다. 조사결과 영양체에서 휴면포자로의 유도는 수온이 높을수록 유도율이 높고 휴면포자의 직경이 커지는 현상이 관찰되었다. 또한 유주자 형성은 고수온, 고염분의 환경에서 잘 형성됨으로써 $10^{\circ}C$ 이하에서는 유주자 발생이 이루어지 않으며, 10 ppt에서는 유주자 형성이 급격히 감소하고 5 ppt에서는 유주자 발생이 이루어지지 않음이 확인되었다. 이러한 퍼킨서스편모충의 생태학적 정보는 이 질병의 구제 대책 수립에 중요한 정보를 제공할 수 있을 것으로 기대된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권1호
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• pp.46-54
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• 2014

This study was conducted to investigate the effects of eucalyptus (E. Camaldulensis) crude oils (EuO) supplementation on voluntary feed intake and rumen fermentation characteristics in swamp buffaloes. Four rumen fistulated swamp buffaloes, body weight (BW) of $420{\pm}15.0$ kg, were randomly assigned according to a $2{\times}2$ factorial arrangement in a $4{\times}4$ Latin square design. The dietary treatments were untreated rice straw (RS) without EuO (T1) and with EuO (T2) supplementation, and 3% urea-treated rice straw (UTRS) without EuO (T3) and with EuO (T4) supplementation. The EuO was supplemented at 2 mL/h/d in respective treatment. Experimental animals were kept in individual pens and concentrate mixture was offered at 3 g/kg BW while roughage was fed ad libitum. Total dry matter and roughage intake, and apparent digestibilites of organic matter and neutral detergent fiber were improved (p<0.01) by UTRS. There was no effect of EuO supplementation on feed intake and nutrient digestibility. Ruminal pH and temperature were not (p>0.05) affected by either roughage sources or EuO supplementation. However, buffaloes fed UTRS had higher ruminal ammonia nitrogen and blood urea nitrogen as compared with RS. Total volatile fatty acid and butyrate proportion were similar among treatments, whereas acetate was decreased and propionate molar proportion was increased by EuO supplementation. Feeding UTRS resulted in lower acetate and higher propionate concentration compared to RS. Moreover, supplementation of EuO reduced methane production especially in UTRS treatment. Protozoa populations were reduced by EuO supplementation while fungi zoospores remained the same. Total, amylolytic and cellulolytic bacterial populations were increased (p<0.01) by UTRS; However, EuO supplementation did not affect viable bacteria. Nitrogen intake and in feces were found higher in buffaloes fed UTRS. A positive nitrogen balance (absorption and retention) was in buffaloes fed UTRS. Supplementation of EuO did not affect nitrogen utilization. Both allantoin excretion and absorption and microbial nitrogen supply were increased by UTRS whereas efficiency of microbial protein synthesis was similar in all treatments. Findings of present study suggested that EuO could be used as a feed additive to modify the rumen fermentation in reducing methane production both in RS and UTRS. Feeding UTRS could improve feed intake and efficiency of rumen fermentation in swamp buffaloes. However, more research is warranted to determine the effect of EuO supplementation in production animals.