• 한국미생물·생명공학회지
• /
• 제31권3호
• /
• pp.297-300
• /
• 2003

In order to select probiotics with a high survival rate in gut and the growth inhibition of virulent pathogens to human beings or animals, we have screened lactic acid bacteria and yeasts from Jeot-gal to assess resistance against the artificial gastric acid and bile juice. Lactic acid bacteria and yeasts isolated were incubated for 24 h in artificial bile juice after incubation for 2 h in artificial gastric acid. Especially, strain HW 161 and strain NK 181 showed the higher survival for 2 h incubation in artificial gastric acid. All of 3 strains of lactic acid bacteria and 2 strains of yeast were showed higher growth rate than the control in artificial bile. The antimicrobial activity of lactic acid bacteria and yeasts was also investigated to prove efficacy as probiotic organisms. Lactic acid bacteria were shown the inhibition of Gram positive and negative bacteria, but yeasts narrow inhibition.

• 수산해양교육연구
• /
• 제29권3호
• /
• pp.702-710
• /
• 2017

Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

• 한국발생생물학회지:발생과생식
• /
• 제21권1호
• /
• pp.101-110
• /
• 2017

On June 14, 2008 (the first experiment) and July 24, 2008 (the second experiment), the shores of the Boseong River and the sandy beaches, Seokgok-myun, Moksadong-myun, Gokseong-gun in Jeollanam Province were investigated and a total of 29 soft-shelled turtle (Tryonyx sinensis) eggs in the natural spawning nest eggs were collected (13 eggs were collected in the first experiment and 16 eggs in the second experiment). The temperatures in the natural spawning nests were $25.9-36.9{\pm}0.5^{\circ}C$, the depth of the eggs was $5.2-7.5{\pm}0.5cm$ as the distance of the average $6.4{\pm}0.5cm$. 29 eggs were scattered at least 0.2 cm interval. Artificial incubation of 29 eggs was conducted in artificial nest boxes in thermo-plastic composition of the incubator, and then incubated at $26.5-35.5{\pm}0.5^{\circ}C$, and an average constant temperature was $31.2-32.1{\pm}1.0^{\circ}C$. The incubation days ranged from 53 to 55. In case of most turtles, incubation at $31^{\circ}C$ (higher temperatures) generally produces all or mostly females, while incubation at $25^{\circ}C$(cooler temperatures) produces all or mostly males. Exceptionally, in case of genus Trionyx, the sex ratio of female : male of T. sinensis of a freshwater soft-shelled turtle was approximately 1:1, which differs from other genera of turtles and makes T. sinensis Strauch only turtles presently known to lack temperature-dependent sex determination.

• 한국동물생명공학회지
• /
• 제36권2호
• /
• pp.82-90
• /
• 2021

In the present study, we examined if deep uterine artificial insemination (DUAI) can improve the pregnancy rate of artificial insemination (AI) using epididymal spermatozoa (ES) in Hanwoo cattle. The estrus cycles of 88 Hanwoo cows were synchronized, and 17 cows were artificially inseminated using the DUAI method with ES, 20 cows were artificially inseminated via the uterine body (BUAI) method with ES, and as a control, 51 cows were inseminated by using the BUAI method with ejaculated spermatozoa from 1 proven bull after frozen thawing. The pregnancy rate of the DUAI method (58.8%) was higher than that of the BUAI method (25.0%, p = 0.0498). The motility of ES was examined immediately after thawing and after 3 and 6 h of incubation. The rapid progressive sperm motility of the control group was significantly higher than that of the ES group immediately after thawing and after 3 and 6 h of incubation (p < 0.05). The straight line velocity and average path velocity of the ES group after 6 h of incubation were significantly lower than those in the control group (p < 0.05). The linearity and amplitude of lateral head of ES were lower than those at 6 h (p < 0.05). The flagellar beat cross frequency and hyperactivation of ES were lower than the control spermatozoa immediately after thawing and at 3 h (p < 0.05). These motility parameters suggested that ES had a low motility and fertilization ability compared to the control spermatozoa. After frozen-thawing and 3 h of incubation, the percentage of live spermatozoa with intact acrosomes in the ES was significantly lower than that in ejaculated spermatozoa (p < 0.05). Our findings suggested that the DUAI method can overcome the low pregnancy rate of ES, despite the low motility, viability, and fertilization ability of ES.

• 한국응용곤충학회지
• /
• 제46권2호
• /
• pp.295-302
• /
• 2007

천잠의 연중 실내사육법을 확립하고자 천잠의 의잠절식, 수시부화 및 최청법을 조사하였다. 천잠의 일시소잠을 위하여 의잠을 절식 실험한 결과, $25^{\circ}C$ 와 $5^{\circ}C$ 에서 1일간 보호한 4령기잠기 생존율이 각각 83.3% 및 96.0% 로 의잠 절식기간의 보호온도가 낮을수록 생존율이 높았다. 연중 다회사육을 위해 수시부화실험을 한 결과, 천잠알을 2개월 냉장할 경우에는 $5^{\circ}C$가 좋았으나 6개월 이상 냉장하여 사용할 경우에는 $2.5^{\circ}C$또는 $0^{\circ}C$에 보호하는 것이 실용부화비율이 높은 것으로 나타났다. 또한 일시부화에 적합한 천잠알의 보호조건을 조사한 결과, 관행적 최청방법 ($25^{\circ}C$ 보호)으로는 5-6일 걸리는 천잠알의 부화가 $15^{\circ}C$ 예비최청과 암최청 방법의 도입으로 2일간에 80% 가 부화하는 좋은 성적을 얻을 수 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제22권7호
• /
• pp.939-946
• /
• 2012

Antibiotic production with Streptomyces sindenensis MTCC 8122 was optimized under submerged fermentation conditions by artificial neural network (ANN) coupled with genetic algorithm (GA) and Nelder-Mead downhill simplex (NMDS). Feed forward back-propagation ANN was trained to establish the mathematical relationship among the medium components and length of incubation period for achieving maximum antibiotic yield. The optimization strategy involved growing the culture with varying concentrations of various medium components for different incubation periods. Under non-optimized condition, antibiotic production was found to be $95{\mu}g/ml$, which nearly doubled ($176{\mu}g/ml$) with the ANN-GA optimization. ANN-NMDS optimization was found to be more efficacious, and maximum antibiotic production ($197{\mu}g/ml$) was obtained by cultivating the cells with (g/l) fructose 2.7602, $MgSO_4$ 1.2369, $(NH_4)_2PO_4$ 0.2742, DL-threonine 3.069%, and soyabean meal 1.952%, for 9.8531 days of incubation, which was roughly 12% higher than the yield obtained by ANN coupled with GA under the same conditions.

• Journal of Animal Science and Technology
• /
• 제45권6호
• /
• pp.987-996
• /
• 2003

본 실험은 수준별 산삼 배양액에 의한 반추위 내 미생물 발효성상에 미치는 영향에 대하여 조사하기 위해 실시되었다. 산삼 배양액의 수준에 따른 반추위 내 발효성상에 미치는 영향은 WGM을 3% 첨가한 처리구가 대조구 및 다른 WGM 수준 첨가 처리구에 비하여 미생물 단백질 합성량이 가장 높게 나타났다. 산삼 배양액 내에 존재하는 saponin의 영향으로 배양 초기 NH3-N 농도의 수준이 WGM를 첨가한 처리구가 대조구에 비해 낮은 경향(P〈0.05)을 보였으나, 미생물단백질 합성량은 WGM 처리구에서 6시간 이후 급격히 증가(P〈0.05)하는 경향을 나타내었다. 따라서 용해도가 높거나 급여 초기 사료의 이용율이 저하되는 급여 체계에서 산삼 배양액을 첨가는 초기 반추위 미생물의 이용율을 조절할 수 있을 것으로 사료된다. 반추위 내 프로토조아의 수는 WGM 처리구에서 전반적으로 배양 9시간까지 낮아졌고, 3% 처리구에서 가장 낮았는데(P〈0.05), 프로토조아 제거효과에 의해 반추위 미생물합성량 증진시키는 효과를 나타내었다. NDF와 ADF 소화율은 대조구와 모든 처리구에서 배양시간 경과에 따라 높아졌고, NDF 소화율은 대조구와 WGM 3% 처리구에서 그리고 ADF 소화율은 처리구별 차이가 없었다. Total VFA 생성량은 처리구가 대조구에 비해 낮았고, 배양 12시간부터는 5% 처리구에서 차이가 없게 나타났다. 따라서 용해도가 높거나 급여 초기 사료의 이용률이 저하되는 급여 체계에서 산삼 배양액을 첨가는 초기 반추위 미생물의 사료 이용률 증진과 프로토조아 제거효과에 의해 반추위 미생물합성량 증진에 도움이 될 수 있을 것이다.

• Journal of Korean Neurosurgical Society
• /
• 제29권9호
• /
• pp.1161-1170
• /
• 2000

Objective : The transverse hippocampal slice is one of the most commonly studied in vitro models of mammalian brain physiology. However, despite its broad usage, there has been no standardization of slice preparation techniques or recording condition. It is well known that variations in recording conditions can result in profound different effects to neuronal responses. Evoked field potentials, recorded extracellularly, were used to investigate the effects of variations in hippocampal slice preparation protocol on hypoxia responses of CA1 neurones. Material & Methods : Before hypoxic injury, hippocampal slices were incubated for 4 hours. During incubation period, the slices were placed in a incubation chamber($21^{\circ}C$) for recovery from preparation injury and then transferred to recording chamber($34^{\circ}C$) for more recovery and baseline electric recording with current stimulation(0.1Hz). Various time periods in incubation chamber and recording chamber were applied to each experimental group(group 1=60min : 180min, group 2=90min : 150min, group 3=180min : 60min, time in incubation chamber : time in recording chamber) before 10 min hypoxia produced by replacing 95% $O_2$+5% $CO_2$ mixed gas to 95% $N_2$+5% $CO_2$ gas. Calcium, Magnesium ions and several drugs effecting on glutamate receptor also were studied. Recoveries from hypoxic injury of hippocampal slices were estimated by percent recovery of population spike(PS). Statistic analysis of study were performed using paired t-test. Results : The percent recovery of PS after 10min hypoxia was considerably enhanced by increasing the period of current stimulation during incubation period before hypoxic injury. Temperature effect on the result of this experiment was also studied(group 4) but the result from this showed no statistic significance. Low magnesium ion concentration of artificial CSF(Mg-free aCSF) during incubation period enhanced the recovery of PS but low calcium (calcium-free) and high magnesium ion concentration(2mM) reduced it after hypoxic injury. L-glutamate($100{\mu}M$) and AP-5($50{\mu}M$) had no effect on the recovery of PS but CNQX($10{\mu}M$) in artificial CSF during incubation period markedly enhanced the recovery of PS. Co-treatment of AP-5($50{\mu}M$), CNQX($10{\mu}M$) and high magnesium concentration(2mM) enhanced recovery of PS in immediate following period of hypoxic injury but the effect of cotreatment after then decayed rapidly and lost statistic significance. Conclusions : Judging from above results, the condition of baseline recording is important in observing the recovery of population spike after hypoxia, and the time and the condition should be controled more strictly to obtain reliable results.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2001년도 추계학술발표대회
• /
• pp.882-885
• /
• 2001

The cells of Lactobacillus plantarum MY4 isolated from the human feces were treated for 24 h in artificial bile after incubation for 2 h in artificial gastric juice and final number of the strain was reached to around $3.1{\times}10^8$ CFU/ml. In test of API ZYM kit, ${\beta}$-glucuronidase or ${\beta}$-glucosidase were not produced by L. plantarum MY4. However, ${\beta}$-galactosidase were weakly produced by it, which they would be alleviated the lactose intolerance. L. plantarum MY4 were resistant to antibiotics such as nisin, tetracycline, streptomycin, rifamycin, doxycycline, roxithromycin, chloramphenicol, nystatin, erythromycin, ciprofloxacin and gentamycin. L. plantarum MY4 was affected by alcohol concentration up to 8%, but more than 16%, their growth was not affected significantly. L. plantarum MY4 was shown to inhibit the growth of Listeria monocytogenes ATCC 19111 completely within 24 h of incubation, which indicates its bactericidal nature. Thus, L plantarum MY4 show promise as a probiotic strain because of its characteristics.

• 한국미생물·생명공학회지
• /
• 제25권6호
• /
• pp.617-622
• /
• 1997

This studies were carried out to investigate the physiological characteristics of lactic acid bacteria related to kimchi fermentation. 157 strains of lactic acid bacteria were isolated from home-made kimchi of Taegu district. 144 strains of isolated lactic bacteria showed resistance to artifical gastric juice and bile. Among isolated strains, fifteen strains were selected according to the growth characteristics. The selected strains survived for 24 hours in artifical bile after incubation for 3 hours in artificial gastric jucie (pH 2.5). Especially, three strains such as B-10, K-2, and F-3, showed little viable cell change for 3 hrs incubation in artifical gastric juice. The selected strains showed low viability in artificial gastric juice but high in artifical bile. The selected strains also showed significantly antimicrobial activities to pathogens such as Listeria monocytogenes, Escherichia coli, Bacillus subtili, Staphylococcus aureus and Vibrio parahaemolyticus. The fifteen selected strains were identified as Lactobacillus plantarum, Lactobacillus sake and Leuconostoc mesenteroides.