• Biotechnology and Bioprocess Engineering:BBE
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• 제8권6호
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• pp.349-353
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• 2003

The physiological characteristics of cultures of very high cell mass (e.g. 10g cell mass/L), termed“ultrahigh cell density cultures”is reviewed. A close relationship was found between the length of the optical path (OP) in flat-plate reactors and the optimal cell density of the culture as well as its areal (g m$\^$-2/ day$\^$-1/) productivity. Cell-growth inhibition (GI) unfolds as culture density surpasses a certain threshold. If it is constantly relieved, a 1.0cm OP reactor could produce ca. 50% more than reactors with longer OP, e.g. 5 or 10cm. This unique effect, discovered by Hu et al. [3], is explained in terms of the relationships between the frequency of the light-dark cycle (L-D cycle), cells undergo in their travel between the light and dark volumes in the reactor, and the turnover time of the photosynthetic center (PC). In long OP reactors (5cm and above) the L-D cycle time may be orders of magnitude longer than the PC turnover time, resulting in a light regime in which the cells are exposed along the L-D cycle, to long, wasteful dark periods. In contrast, in reactors with an OP of ca. 1.0 cm, the L-D cycle frequency approaches the PC turnover time resulting in a significant reduction of the wasteful dark exposure time, thereby inducing a surge in photosynthetic efficiency. Presently, the major difficulty in mass cultivation of ultrahigh-density culture (UHDC) concerns cell growth inhibition in the culture, the exact nature of which is awaiting detailed investigation.

• 대한핵의학회지
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• 제3권2호
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• pp.1-16
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• 1969

The double tracer study on erythrokinetics was carried out experimentally with radioactive iron ($^{59}Fe$) and chromium ($^{51}Cr$) in rabbits. The 0.1% canthalidin solution and 1% pot. perchlomate solution was given subcutaneously to 20 rabbits respectively. 3 and 6 days after injection, the blood chemistry, urine examination, ferrokinetics and apparent half survival time of RBC were ($^{51}Cr\;T\frac{1}{2}$)determined. Following were the results: 1) Red blood cell hematocrit and hemoglobin values were moderately reduced and B.U.N. and serum creatinine values were slight]y inercased in the canthalidin group, while B.U.N. and serum creatinine values were within normal limits in the pot. perchlomate group. Reticulocyte values were slight]y increased in the canthalidin group, while was normal range in the pot. perchlomate group. 2) Blood chemistry finding was not significant statistically in both experimental groups, but serum iron value was moderately reduced in both group. 3) Plasma volume was unchanged in both group, but red cell volume and whole blood volume were slightly reduced in both groups. 4) Results of ferrokinetics were as follows: i) The plasma iron disappearance rate was delayed in both groups. Plasma iron turnover rate, red cell iron utilization and red cell iron turnover rate were decreased in both groups, and then red cell iron turnover rate was more decreased than plasma iron turnover rate in both groups. Circulating red cell iron was slight]y increased in canthalidin group and red cell iron concentration was within normal range in both groups. ii) P.I.T.R.-R.C.I.T. value was moderately increased in the canthalidin group and slightly increased in the pot. perchlomate group. Reticulocyte index, red cell iron turnover index, plasma iron turnover index and effective erythropoiesis index were whole]y reduced in both groups. iii) The red cell life span was slightly shortened in the canthalidin group while was within normal range in pot. perchlomate group. The pathologic finding of renal biopsy of the canthalidin group shows a selective damage in glomerulus, while shows almost normal range or slight damage in tubules. And that of the pot. perchlomate group shows a selective damage in tubules with slight damage of glomerulus.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.63-69
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• 2003

Ten barrows, weaned at 28 days (7.2$\pm$0.1 kg BW), were used to evaluate the effects of feeding extruded full-fat soybeans on intestinal morphology and mucosal cell turnover time. All pigs were fed corn-based diets with half of the pigs receiving diets supplemented with 15.5% soybean meal and 3% soybean oil and the remaining pigs fed a diet in which the soybean meal and oil were replaced by 18.5% extruded full-fat soybeans. The pigs were individually placed in $80{\times}150cm$ metabolic cages and fed twice daily an amount approximately equal to their ad libitum intake for a period of 14 days. On day 14, pigs were weighed and then injected intraperitoneally with $^3$H]thymidine ($100{\mu}Ci/kg$ of BW, specific activity 20 Ci/mmol) 6 h after the morning meal. A pig from each treatment was killed 1, 4, 8, 16, or 24 h postinjection and intestinal tissues were collected. Daily gains for pigs fed the soybean diet and extruded full-fat soybean diet were 0.24 and 0.31 kg/day (p=0.05) with feed conversions of 1.58 and 1.39 (p=0.05), respectively. In comparison with pigs fed soybean meal, pigs fed moist extruded full-fat soybeans had a decreased crypt depth in their duodenum and cecum (p<0.1), while the villus height in the mid jejunum and ileum and the total height (villus height plus crypt depth) of the ileum and mid jejunum increased (p<0.05). The villus width in the duodenum and mid jejunum decreased (p<0.05). The number of crypt epithelial cells in the upper jejunum increased but decreased in the ileum, colon and cecum (p<0.05). The number of villus epithelial cells in the ileum and the upper and mid jejunum increased (p<0.05). The time for migration of epithelial cells in the crypt-villus column decreased (p<0.05) in all sites except the upper jejunum, ileum and cecum. The mucosal turnover rate for all intestinal sites except the upper jejunum, colon and cecum decreased (p<0.05). From these data, we conclude that inclusion of moist extruded full-fat soybeans in weanling pig diets can improve the intestinal morphology and slow the migration rate and turnover time of epithelial cells of the small intestine, especially in the mid jejunum compared with soybean meal.

• Asian-Australasian Journal of Animal Sciences
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• 제24권4호
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• pp.485-492
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• 2011

The influence of high temperature on mammary cell turnover during the dry period is still unclear. The objective of this study was to investigate mammary cell turnover and p53 protein expression in the mammary tissue under high temperature conditions. Mammary gland biopsy samples from 8 dairy cows were obtained at 7, 25, 40, and 53 d during the dry period in summer or spring (n = 4, each season). Cell cycle, cell turnover, and p53 protein expression were analyzed by flow cytometry. During the dry period in summer, the percentage of mammary epithelial cells in the G0/G1 phase was the highest, but those in the S and G2/M phases were lower. However, the proportion of cells in the different stages of the cell cycle was not significantly different among the different biopsy time points, except in the G2/M phase. Under different temperature conditions, the cells were significantly different in their apoptotic rate and proliferation index; moreover, the tendencies of these indicators to change significantly differed. In general, the samples under high temperature conditions showed significantly lower apoptotic rates and proliferation indices. Under high temperature conditions, the apoptotic rate and proliferation index were the lowest (2.17% and 3.26%, respectively) at day 40, and the highest at day 53 (3.67% and 4.61%, respectively). However, under normal temperature conditions, the values of these indicators were the lowest (7.60% and 5.54%, respectively) at day 7, and almost the highest at day 25 (12.85% and 6.47%, respectively). Moreover, p53 protein expression was significantly higher under high temperature conditions than under normal temperature conditions, except at day 25. The level of p53 protein was the lowest (13.10%) under high temperature conditions at day 25, but was the highest (26.07%) under normal temperature conditions. Our findings suggest that high temperature delayed the G2/M phase of the cell cycle and the cell turnover rate, but remarkably increased p53 protein expression. Thus, the results indicate that high temperature extends the recovery period of mammary epithelial cells.

• 대한핵의학회지
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• 제1권2호
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• pp.61-74
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• 1967

In order to confirm whether acquired immunity or resistance can be developed by the repeated hookworm infections, the 150 mature actively moving filariform ancylostoma duodenale larvae obtained from the severe hookworm anemia patients were orally given to 8 healthy volunteers in three divided doses, 50 in each, at 5 day interval. Also the hematological changes as well as several ferrokinetics using $^{59}Fe$ were done and were compared with 10 controls. The clinical symptoms and signs were checked every day for the first 3 weeks and then twice weekly until the end of the experiment. The appearance of the ova in the stool was examined by the formalin ether method and the ova was counted by the Stoll's method. The following laboratory tests were done: 1) Red blood cell count, venous blood hematocrit(micromethod), hemoglobin count (cyanomethemoglobin method) were checked every 5 to 7 day interval. 2) Plasma iron concentration (Barkan's modified method) was determined every 2 to 3 week interval. 3) Radioisotope studies: a) Ferrokinetics: Huff et al and Bothwell's method were applied. Erythropoietic Index (% of normal)=$\frac{Subject's\;turnover/100ml\;whole\;blood{\times}100}{Average\;normal\;turnover/100ml\;whole\;blood}$ of the gastrointestinal absorption of iron: Radioiron($^{59}Fe$) balance b) Quantitative measurement method was applied. c) Determination of the plasma erythropoietin activity: Fried's method was applied. Following were the results: 1) The serum iron level was lower. The red cell volume was decreased, but with relative increase of plasma volume. 2) The plasma iron disappearance time was accelerated and the plasma iron turnover rate was decreased. The red cell iron turnover rate was markedly increased, while all of the red cell iron concentration, circulating red cell iron. plasma iron pool were decreased. The daily iron pool turnover and red cell renewal rate were increased. 3) The erythropoietic index, erythropoietin activity and intestinal absorption of iron($^{59}Fe$) were markedly increased. 4) The infectivity was $9.8{\pm}1.31%$ which was lower than that observed in the single infection. 5) From these observations, it is concluded that the hookworm anemia is essentially iron deficieny in its origin and some immunity acquisition is possible with repeated infections.

• 한국동물학회지
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• 제30권2호
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• pp.193-209
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• 1987

Patterns of amylase secretion in mouse pancreatic fragments were studied over a period of time after the tissue was stimulated by acetyicholine and MNNG. MNNG is known to activate guanylate cyclase and thus increase the cGMP concentration in the pancreatic acinar cell. These amylase secretion patterns were studied to investigate the role of cGMP in reaction cascade during secretion response of the tissues stimulated by acetyicholine. Cellular response of amylase secretion in the pancreas by acetyicholine was divided into two phases. During the first phase, zymogen granules which had existed in the cells were secreted by the action of $Ca^2$+ and calmodulin immediately after secretagogue administration, this being known as the initial response. When the tissue was stimulated by acetylcholine in a $Ca^2$+-deficient medium or one containing trifluoperazine as a calmodulin antagonist, this initial response was reduced. In the second phase, newly formed zymogen granules were secreted as sustained response after protein synthesis was triggered by secretagogue. This response was provoked by an activation of protein kinase C. When either cycloheximide as a protein synthesis inhibitor or dibucaine as a protein kinase C inhibitor were added to the incubation medium, this sustained response was remarkablely depressed in the pancreatic fragments stimulated with acetylcholine. In the pancreatic acinar cell, phosphatidylinositol turnover plays an important role in the secretion response and hexachlorocyclohexane inhibits this phosphatidylinositol turnover. The pancreatic tissue treated with the hexachlorocyclohexane exhibited inhibition on both initial and sustained responses of amylase secretion by acetylcholine. MNNG also accelerated amylase secretion from the tissue gradually along incubation time. The 22 minutes fraction of the pancratic secretion after administration of both acetylcholine and MNNG showed higher amylase activity than the neighboring fractions. Guanylate cyclase potentiated the sustained response. Even if it is experimented with an indirect method, guanylate cyclase was found responsible for activation of the sustained response of a step prior to the action of protein kinase C. As conclusion, it was considered that amylase secretion in mouse pancreatic fragments stimulated by acetylcholine is a three phasic response.

• The Korean Journal of Physiology
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• 제15권1호
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• pp.9-18
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• 1981

For centuries, ginseng has been used for the therapeutic purpose in oriental herb medicine. Several studies have been conducted in the past to evaluate the effect of ginseng on erythropoiesis. However the results were controversial. We therefore attempted in the present studies to evaluate the effect of ginseng on the erythropoietic activity. In one series of experiments, the recovery pattern of peripheral blood(red cell count, hemoglobin content, hematocrit and reticulocyte count) was studied in posthemorrhagic anemic rabbits. After animals were maintained with normal(control group) or 1 gm% ginseng (experimental group) diet for 2 weeks, hemorrhagic anemia was induced by withdrawing blood equivalent to 25% of the total blood volume and then changes in peripheral blood were followed for following 30 days. In other series of experiments, we studied effect of ginseng on erythrokinetics using $^{59}Fe$. $^{59}Fe(10{\sim}40\;{\mu}Ci/animal)$ was injected intravenously after animals were fed with normal (control group) or 1 gm% ginseng(experimental group) diet for 2 weeks. And radioactivities in the blood compartments were measured at appropriate intervals for 15 days. Front these various erythrokinetic parameters were estimated. Results are summarized as follows: 1) Reticulocyte count was higher in the experimental group than in the control group after 2 weeks of administration of experimental diet. During the posthemorrhagic period, the reticulocyte count increased in both the control and experimental groups, but the increase appeared much earlier in the experimental group. 2) The posthemorrhagic recoveries of hematocrit, hemoglobin content and red cell count appeared to be faster in the experimental group as compaired with the control group. 3) The half life$(T_{1/2})$ of $^{59}Fe$ in the plasma was significantly(P<0.05) shorter in the experimental group(82.6 min, N=8) than in the control group(121 min, N=6). Plasma iron turnover (PIT) of the experimental group (1.78 mg/dl/24 hr.) was approximately 4 times greater than that of the control group(0.45 mg/dl/24 hr.). 4) The maximum red cell utilization(RC-U) was 82.1% in the experimental group ana 74.5% in the control group. Red cell iron turnover(RIT) of the experimental group(1.62 mg/dl/24 hr.) was slightly higher than that of the control group(0.35 mg/dl/24 hr). 5) Erythron turnover was significantly(p<0.05) greater in the experimental group(1.27 mg/dl/24 hr.) than in the control group(0.24 mg/dl/24 hr.). Marrow transit time of the experimental group(2.05 days) tended to he faster than that of the control group(2.84 days). These results suggest that the gingseng improves the recovery of posthemorrhagic anemia and stimulates the erythropoiesis in rabbits.

• Journal of Plant Biotechnology
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• 제37권1호
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• pp.57-66
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• 2010

Programmed cell death systems are important for an active type of cell deaths. Among them, a type of programmed cell death, autophagy is activated in cancer cells in response to multiple stresses and has been demonstrated to promote tumor cell survival and drug resistance. Thus, in the area of cancer, over the time frame form around the 1940s to date, of the 155 small molecules, 73% are other than "synthetic", with 47% actually being either "natural products" or "directly derived therefrom". Autophagy has multiple physiological functions in multicellular organisms, including protein degradation and organelle turnover. Genes and proteins that constitute the basic machinery of the autophagic process were first identified in the yeast system and some of their mammalian orthologues have been characterized as well. Numerous oncogenes, including Akt1, Bcl-2, NF1, PDPK1, class I PI3K, PTEN, and Ras and oncosuppressors, inculuding Bec-1, Bif-1, DAPK-1, p53 and UVRAG suppress or promote the autophagy pathway. Regulation of autophagy in tumors is governed by similar principles of the normal cells, only in a much more complicated manner, given the frequently observed abnormal PI3K activation in cancer and the multitude of interactions between the PI3K/AKT/mTOR pathway and other cell signaling cascades, often also deregulated in tumor cells. Autophagy induction by some anticancer agents underlines the potential utility of its induction as a new cancer treatment modality of development for natural medicines.

• Journal of Plant Biology
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• 제11권1호
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• pp.15-21
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• 1968

Chlorella ellipsoidea were grown in a Mg-free medium. Aliquots of the algal cell were taken out at the beginning and predetermined time intervals during the culture and were analyzed the contents of phosphate in various fractions of the cell constituents. The results obtained were compared with those of the control. When Chlorella cells were grown in a Mg-free medium, the contents of phosphate in the DNA protein, RNA-olyphosphate complex, nucleotidic-lbileP, and PCA-soluble, fractions decreased compared with those of the control, while the content of acid insoluble polyphosphate increased significantly. On the otherhand, RNA-P and lipid-P showed the tendency of decrease at the early stage of the culture, but they were increased more than those in the control as culture proceeds. It is showed that phosphate turnover from acid-insoluble polyphosphate into DNA, protein, and RNA-polyphosphate complex was inhibited by magnesium-deficiency of the cells.

• 한국해양학회지
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• 제26권1호
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• pp.67-76
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• 1991

마산만은 부영영화의 영향으로 적조와 무산소층이 빈발하는 해역으로 알려져 있 다. 이 해역의 빠른 turnover rate를 고려할 때 보다 짧은 관측 간격을 필요로 하므 르, 1988년 여름 장마 직후 16일간 일일관측을 실시하였다. 비교적 짧은 조사기간에도 불구하고 식물플랑크톤의 양 및 조성에 큰 변화가 있었다. 세포수와 클로로필 농도는 각각 70, 10배의 변화폭을 보였다. 식물플랑크톤 현존량의 첫 번째 최고점에서는 규조 류인 Skeletonema costatum이 압도적 우점종으로 나타났고, 이는 약 1주일 후의 두 번 째 최고점에서 Prorocentrum minimum으로 우점종의 천이가 일어났다. 이러한 변화의 시간 규모로 볼 때 마산만과 같은 복잡한 연안환경에서는 적어도 1주 간격의 조사가 고려되어야 할 것이다. 성층은 표층에서 높은 성장을 가능하게 했던 반면, 저층에서 표층으로의 규산염 공급을 방해하여 규조류의 지속적인 성장을 제한한 것으로 보인다. 표층에서 잇따라 일어났던 규산염 및 규조류 양의 두 번째 최고점은 조류 (tidal current)에 의한 저층으로부터 불연속면을 거쳐 일어나는 규산염의 주기적 (flux)를 시사한다.