• 한국어병학회지
• /
• 제30권1호
• /
• pp.11-24
• /
• 2017

The current investigation dealing with the causative agent of mass mortalities in cultured Oreochromis niloticus. The diseased fish showed external hemorrhage, unilateral and bilateral eye opacity, ended by blindness and fish death. The postmortem lesions revealed congested friable kidney and spleen, and liver has yellow nodules. Obtained isolates were identified as Aeromonas hydrophila (the causative agent of Motile Aeromonas Septicemia) and found to be highly pathogenic as they contained hemolysin virulence gene causing mortality reached to 100 and 70% in intraperitoneal and intramuscular infection. The prevalence of MAS was 80% among the surveyed O. niloticus. Blood and serum were collected from naturally diseased, intraperitoneal and intramuscular injected O. niloticus for hematological and biochemical examination. Similarly, gills, musculature, kidney, liver and spleen were collected for histopathological evaluation, and micropathomorphological analysis of spleen was done. Macrocytic hypochromic anemia was recorded in the intraperitoneal infection. Serum protein, albumin and globulin were decrease only in naturally diseased fish. Leucocytosis with heterophilia and lymphocytosis were observed in naturally diseased and intraperitoneal infected fish. There were severe degenerative changes and hemorrhagic necrosis in the examined tissues which were more obvious in intraperitoneal than intramuscular infection. Activation and proliferation of melanocytes macrophages centers with severe hemosiderosis were recorded in spleen of naturally diseased and experimentally infected fish.

• 자연과학논문집
• /
• 제8권2호
• /
• pp.147-152
• /
• 1996

딸기의 3품종을 엽과 엽병으로 배양한 결과 2,4-D + BA 처리에서는 치밀한 캘러스가 유기되었고 이 캘러스로부터 다수의 신초가 분화되었으며 NAA + BA 처리에서는 부숴지기 쉬운 캘러스가 유기되었다. '수홍' 엽조직을 NAA나 2,4-D가 첨가된 배지에서 8개월간 배양하면 212번 primer에서 생산된 RAPD band가 모본 band와는 상이하게 나타났다. '보교'와 '여봉'의 엽에서 유기된 캘러스를 2,4-D가 첨가된 액체배지에 계대배양회수를 달리하여 배양하였을 때 12회 계대배양에서 모본과 상이한 RAPD band가 출현되었다.

• Journal of Plant Biology
• /
• 제14권3호
• /
• pp.1-20
• /
• 1971

Ecological factors limiting Stipa pulchra have been determined in experimental gardens and at several sites in the hills south and east of Monterey, California. The Stipa pulchrafacies of Valley Grassland communities were found to be dominated by that species, though a total of 36 grasses and forbs were collected and identified. Basal area was not large, but aerial cover by Stipa alone averaged over 50 per cent. Across an ecotone between a Stipa association and the California Annual Type a sudden and dramatic change was recorded. Soil measurements there, and in other nearby areas, showed a much higher clay content with more available water and elemental phosphorus at the Stipa sites. Germination of Stipa seeds was high under all laboratory and field conditions, though growth of seeldings was highly variable. Seedlings grown in Stipa woil with an abundance of water were vigorous and reached anthesis the first year. In other soils they grew less, and when grown in competition with Avena fatua they scarcely grew at all. These findings indicate that when established on desirable soils, Stipa competes well and apparently precludes the dominance of Avena fatua and other large annual grasses. On the other hand, because of a lack of vigor in its seedlings, Stipa cannot reinvade the rich more friable soils on which it was once found, and on which it was shown to grow satisfactorily. This supports the contention that Sipa pulchra was the dominant grass through much of the Valley Grassland and Foothill Woodland, but also indicates that well-drained soils and those poor in mineral nutrients probalby never supported such associations.

• 대한수의학회지
• /
• 제45권1호
• /
• pp.99-103
• /
• 2005

We report septicemic colibacillosis accompanied by white-spotted kidney in a 30-day old female Holstein-Friesian dairy calf. Grossly, there were numerous white spots sized average 0.5cm in diameter in both kidneys. When sectioned sagittally, there were radially oriented gray streaks extending outward and reaching the renal cortex. The renal papillae were ulcerated, white to gray in color and very friable. Histologically, there was extensive purulent inflammation characterized by severe neutrophilic cellular infiltrations in the tubular lumens and interstitia. In addition, massive coagulative necrosis were found in the apices of papillae. Numerous Gram-negative bacterial colonies were detected in both of the renal and lung tissues. Beta-hemolytic Escherichia coli (E. coli) was purely isolated from the renal parenchyma, peritoneal surface and pleural surface. Based on the above results, we suggest that the generalized septicemia with pyelonephritis may be oriented from the lower urinary tract infection with E. coli in this case.

• 대한세포병리학회지
• /
• 제19권2호
• /
• pp.164-167
• /
• 2008

Malakoplakia is an uncommon chronic granulomatous inflammation that usually involves the urinary and gastrointestinal tracts, but rarely affects the female genital tract. We experienced a case of malakoplakia in a cervicovaginal smear in a 54-year-old woman. Colposcopic examination showed a friable, easily bleeding tissue in the uterine cervix and the vaginal fornix. The cervicovaginal smear consisted of numerous isolated histiocytes, polymorphonuclear leukocytes, lymphocytes, and plasma cells. The histiocytes had an abundant, granular, and degenerated cytoplasm with inflammatory cell debris. Michaelis-Gutmann bodies were readily identified.

• 한국초지조사료학회지
• /
• 제15권2호
• /
• pp.101-105
• /
• 1995

다섯가지 품종의 레드 클로-버의 캘러스 유도에 미치는 몇가지 요인을 밝히기 위하여 본 실험을 행하였으며, 얻어진 결과는 아래와 같았다. Callus유도에서 auxin원으로서 0.1 ml/l의 picloram이 가장 효과적인 것으로 나타났으며, 여러 종류의 배지중에서는 PC(Phillips & Collins)배지가 가장 callus 형성이 좋았다. PC 배지에서 생성된 callus는 다른 배지에서 생선된 callus보다 더 무른 것이 특징이었다. 배지의 pH는 5.8이 가장 좋았으며 6.2이상에서는 callus의 형성이 급격히 나빠졌다. Explant 재료로서의 식물체는 5~7일령이 가장 좋았고, 15일령 이상은 매우 좋지 못했다. Agar농도도 callus의 형성에 영향을 미쳤는데, 0.5~0.7%가 가장 좋았고 1% 이상에서는 callus형성이 매우 좋지 못하였다.

• Journal of Plant Biotechnology
• /
• 제46권1호
• /
• pp.17-21
• /
• 2019

Ginger is an important monocotyledonous plant belonging to the family Zingiberaceae. The objective of this study was to investigate the regeneration potential of ginger using leaf base explants. Auxins such as 2, 4-D and NAA in combination with BA were used for initiation of callus. Different combinations of both ammonium ($NH^{4+}$) and nitrate ($NO^{3-}$) were also studied for efficient callus production. High frequency of white friable calli was observed on modified Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 2, 4-D, 0.5 mg/L NAA and 0.5 mg/L BA. The highest shoot induction (92.33%), shootlets number ($7.33{\pm}0.33$) and length ($88.33{\pm}4.40$) mm were achieved on MS media containing 0.5 mg/L BA. Regenerated shoots were transferred to in vitro rooting media containing 1.0 mg/L IBA. Afterwards, plantlets with well-developed root and shoot system were subjected to a twostep hardening process. 71% of plantlets survived after secondary hardening without any abnormal morphology.

• Journal of Plant Biotechnology
• /
• 제6권1호
• /
• pp.55-61
• /
• 2004

Callus induction and somatic embryogenesis are fundamental to cotton tissue culture biotechnology. An efficient protocol for callus induction, somatic embryogenesis and their maturation have been developed to regenerate plantlets from cotton (Gossypium hirsutum L.) variety coker 312. Embryogenic callus was initiated from hypo-cotyl region that was used as an explant at seedling stage when it was about 7-8 days old. Callus induction was achieved through culturing hypocotyls (5-7mm) on $MS_{1a} medium supplemented with 2,4-D (0.1 mg/L) and KT (0.5 mg/L) for six weeks. A friable, colorless, bulky and well proliferating callus becomes greenish with the addition of NAA (2.0 mg/L), ZT (0.1 mg/L) and removal of 2,4-D (M $S_{1b}$) cultured for two weeks then again transferred to $MS_{1a}. 2,4-dichlorophenoxyacetic acid (2,4-D) promoted the proliferation of embryogenic callus, but had a negative effect on the differentiation and germination of somatic embryos. ZT (0.1mg/L) and activated charcoal (2g/L), both hormones play an important role in differentiation and germination of somatic embryos in hypocotyls derived embryogenic callus but in case of cotton, such a capability have been observed on MS medium with 1.92 g/L $KNO_3$, but it is considered to attain somewhat more improvement. High embryogenesis frequency was achieved through nutrient deficient stress treatment. The frequency of globular embryogenesis (two-three folds) was achieved when well proliferating callus was (from $MS_{1a}$ media) cultured on MS (1/5 strength) medium for four weeks. Here the development of anthocyanins is the best indicator for somatic embryogenesis. However, when embryoid callus was cultured on MS (full strength) medium, the globular embryos were developed into normal plantlets immediately. In this procedure 27.49% cotyledenary embryos were developed. Of that 70% cotyledenary embryos were developed not only into normal plantlets but rooted simultaneously, when cultured on MS (with 0.05 mgg/L giberrelic acid) medium. So complete plants could be regenerated through somatic embryogenesis from hypocotyl explants within 6 months.s.

• 한국작물학회지
• /
• 제58권4호
• /
• pp.331-335
• /
• 2013

Buckwheat sprout is used as vegetable, and also flour for making noodles, and so on. Currently, information about tissue culture in buckwheat is limited and restricted to micro-propagation. We carried out somatic embryogenesis and plant regeneration using hypocotyl segments as explant of the cultivated buckwheat species, Fagopyrum esculentum which differs from existing studies in the growth regulator combinations used. Maximum callus regeneration was induced on MS medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) $2.0mg{\cdot}L^{-1}$, benzyladenine (BA) $1.0mg{\cdot}L^{-1}$ and 3% sucrose. Friable callus was transferred to solidified MS media containing BA ($1.0mg{\cdot}L^{-1}$) with various concentrations of 2,4-dichlorophenoxyacetic acid for the induction of embryogenesis. The optimum concentrations of growth regulators (for regeneration of plantlet) were indole-3-acetic acid ($2.0mg{\cdot}L^{-1}$), Kinetin ($1.0mg{\cdot}L^{-1}$), BA ($1.0mg{\cdot}L^{-1}$). Only 2,4-D did not show any significant effect on callus induction or embryogenesis. Regeneration of embryonic callus varied from 5% to 20%. Whole plants were obtained at high frequencies when the embryogenic calli with somatic embryos and organized shoot primordia were transferred to MS media with 3% sucrose. The main objective of this research was to develop an efficient protocol for plant regeneration for common buckwheat, and to apply in future for genetic transformation.

• 대한수의학회지
• /
• 제34권3호
• /
• pp.593-599
• /
• 1994

This study was carried out to investigate the necrotic enteritis of chicken in Korea. Epidemiological, pathological and microbiological examination were done on 12 naturally occurred cases of necrotic enteritis of chicken. And the susceptibility of isolated bacteria to antimicrobial agents was also examined. The results obtained were as follows; 1. The Clostridium perfringens infection, necrotic enteritis of chicken, occurred in the chickens mainly raised in floor pens. Necrotic enteritis of chicken was occurred coincidently with coccidiosis and Gumboro disease frequently. And several cases were recurred at 2-3 weeks after recovery. 2. Clinical signs of the infected chickens were depression, decreased appetite, reluctance to move, diarrhea, ruffled feathers and acute death within several hours. 3. The characteristic biochemical properties of isolates were 2-band hemolysis, no motility, positive reaction of reverse CAMP test and the formation of LV precipitate in egg yolk medium. 4. Gross lesions of the infected chickens were distention of intestine with gas, thickened mucosa and formation of thick pseudomembrane in intestine. Livers were friable with yellowish brown color and, in some case, showed demarcated necrotic foci. 5. Histopathological findings of the infected chickens were severe necrosis of the intestinal mucosa and attachment of numerous large bacilli to the mucosal surface of necrotic villi. In liver, necrosis of liver tissue and numerous large bacilli in the necrotic foci were also observed. 6. In susceptibility test to antimicrobial agents, 12 isolates of Clostridium perfringens were highly sensitive to ampicillin, baytril, cephalothin and penicillin.