• 한국초지학회:학술대회논문집
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• 한국초지조사료학회 2001년도 제25회 정기총회 프로그램 제39회 학술발표회 및 특별강연 초록(한국초지학회)
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• pp.95.2-96
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• 2001

• Animal cells and systems
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• 제5권3호
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• pp.163-177
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• 2001

Most, if not all, aphids harbor intracellular bacterial symbionts, called Buchnera, in their bacteriocytes, huge cells differentiated for this purpose. The association between Buchnera and aphids is so intimate, mutualistic and obligate that neither of them can any longer reproduce independently. Buchnera are vertically transmitted through generations of the host insects. Evidence suggests that Buchnera were acquired by a common ancestor of aphids 160-280 million years ago, and have been diversified, since then, in parallel with their aphid hosts. Molecular phylogenetic analyses indicate that Buchnera belong to the g subdivision of the Proteobacteria. Although Buchnera are close relatives of Escherichia coli, they contain move than 100 genomic copies per cell, and their genome size is only one seventh that of E. coli. The complete genome sequence of Buchnera revealed that their gene repertoire is quite different from those of parasitic bacteria such as Mycoplasma, Rickettsia and Chlamydia, though their genome sizes have been reduced to a similar extent. Whereas these parasitic bacteria have lost most genes for the biosynthesis of amino acids, Buchnera retain many of them. In particular, Buchnera's gene repertoire is characteristic in the richness of the genes for the biosynthesis of essential amino acids that the eukaryotic hosts are not able to synthesize, reflecting a nutritional role played by these symbionts. Buchnera, when housed in the bacteriocyte, selectively synthesize a large amount of symbionin, which is a homolog of GroEL, the major stress protein of E. coli. Symbionin not only functions as molecular chaperone, like GroEL, but also has evolutionarily acquired the phosphotransferase activity through amino acid substitutions. Aphids usually profit from Buchnera's fuction as a nutritional supplier and, when faced with an emergency, consume the biomass of Buchnera cells as nutrient reserves.

• 한국토양비료학회지
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• 제47권2호
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• pp.80-84
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• 2014

Phosphorus (P) is an essential nutrient for all living organisms. P is mostly obtained from mined rock phosphate. However, existing rock phosphate reserves could be exhausted in the next 50-100 years. As Korea is totally dependent on imported rock phosphate, we should seek for solution to overcome the P depletion by efficient use and recycling. For this, this study suggested a P flow model to identify the location and flow route of P in urban area based on traditional material flow analysis. The type of P entering the urban areas are fertilizer, food and feed. Each type of P is used in agriculture, human consumption and animal husbandry. After going through each process, P is moved to waste management facilities within food waste, excreta and sewage. Some portion of P in waste are buried, incinerated and discharged, which can be reservoir of P in the future.

• Asian-Australasian Journal of Animal Sciences
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• 제14권5호
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• pp.720-732
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• 2001

Skeletal muscle is of major economic importance since it is finally converted to meat for consumers. The increase in meat production with low costs of production may be achieved by optimizing muscle growth, whereas a high meat quality requires, among other factors, the optimization of intramuscular glycogen and fat stores. Thus, research in energy metabolism aims at controling muscle metabolism, but also liver and adipose tissue metabolism in order to optimize energy partitioning in favour of muscles. Liver is characterized by high anabolic and catabolic rates. Metabolic enzymes are regulated by nutrients through short-term regulation of their activities and long-term regulation of expression of their genes. Consequences of liver metabolic regulation on energy supply to muscles may affect protein deposition (and hence growth) as well as intramuscular energy stores. Adipose tissues are important body reserves of triglycerides, which result from the balance between lipogenesis and lipolysis. Both processes depend on the feeding level and on the nature of nutrients, which indirectly affect energy delivery to muscles. In muscles, the regulation of rate-limiting nutrient transporters, of metabolic enzyme activities and of ATP production, as well as the interactions between nutrients affect free energy availability for muscle growth and modify muscle metabolic characteristics which determine meat quality. The growth of tissues and organs, the number and the characteristics of muscle fibers depend, for a great part, on early events during the fetal life. They include variations in quantitative and qualitative nutrient supply to the fetus, and hence in maternal nutrition. During the postnatal life, muscle growth and characteristics are affected by the age and the genetic type of the animals, the feeding level and the diet composition. The latter determines the nature of available nutrients and the rate of nutrient delivery to tissues, thereby regulating metabolism. Physical activity at pasture also favours the orientation of muscle metabolism, towards the oxidative type. Consequently, breeding systems may be of a great importance during the postnatal life. Research is now directed towards the determination of individual tissue and organ energy requirements, a better knowledge of nutrient partitioning between and within organs and tissues. The discovery of new molecules (e. g. leptin), of new molecular mechanisms and of more powerful techniques (DNA chips) will help to achieve these objectives. The integration of the different levels of knowledge will finally allow scientists to formulate new types of diets adapted to sustain a production of high quality meat with lower costs of production.

• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.227-235
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• 2016

Ultrastructural studies on oocyte development and vitellogenesis in oocytes, and the functions of follicle cells during oogenesis and oocyte degeneration were investigated to clarifyb the reproductive mechanism on vitellogenesis of Scapharca subcrenata using electron microscope observations. In this study, vitellogenesis during oogenesis in the oocytes occured by way of autosynthesis and heterosynthesis. Of two processes of vitellogenesis during oogenesis, the process of endogenous autosynthesis involved the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum. However, the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors at the basal region of the oolema of the early vitellogenic oocytes before the formation of the vitelline coat. In this study, follicle cells, which attached to the previtellogenic and vitellogenic oocytes, were easily found. In particular, the follicle cells were involved in the development of previtellogenic oocytes by the supply of nutrients, and vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors. Based on observations of follicle cells attached to degenerating oocytes after spawning, follicles of this species are involved in lysosomal induction of oocyte degeneration for the resorption phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves. In this study, the functions of follicle cells can accumulate reserves of lipid granules and glycogen particles for vitellogenesis from degenerating oocytes after spawning.

• 한국토양비료학회지
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• 제44권1호
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• pp.78-83
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• 2011

Phosphorus (P) which is required by all living plants and animals is an important input for economic crop and livestock production systems. Phosphorus containing compounds are essential for photosynthesis in plants, for energy transformations and for the activity of some hormones in both plants and animals. Loss of soil P to water can occur in particulate forms of P with eroded surface soil and in soluble forms in runoff, soil interflow, and deep leaching. The excessive losses of P from agricultural systems can degrade water quality of surface waters, resulting in accelerating eutrophication. Thus, P is often the limiting element and its control is of prime importance in reducing the accelerated eutrophication of surface waters. However, reserves of phosphate begin to run out, the impacts are likely be immense in terms of rising food prices, growing food insecurity. This paper reviews underappreciated resource as a key component of fertilizers and one of controversial pollutant in terms agronomy and environment.

• 한국발생생물학회지:발생과생식
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• 제18권4호
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• pp.321-327
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• 2014

Ultrastructural studies of oocyte degeneration in the oocyte, and the functions of follicle cells during oocyte degeneration are described to clarify the reproductive mechanism on oocyte degeneration of Mactra chinensis using cytological methods. Commonly, the follicle cells are attached to the oocyte. Follicle cells play an important role in oocyte degeneration. In particular, the functions of follicle cells during oocyte degeneration are associated with phagocytosis and the intracellular digestion of products. In this study, morphologically similar degenerated phagosomes (various lysosomes), which were observed in the degenerated oocytes, appeared in the follicle cells. After the spawning of the oocytes, the follicle cells were involved in oocyte degeneration through phagocytosis by phagolysosomes. Therefore, it can be assumed that follicle cells reabsorb phagosomes from degenerated oocytes. In this study, the presence of lipid granules, which occurred from degenerating yolk granules, gradually increased in degenerating oocytes. The function of follicle cells can accumulate reserves of lipid granules and glycogen in the cytoplasm, which can be employed by the vitellogenic oocyte. Based on observations of follicle cells attached to degenerating oocytes after spawning, the follicle cells of this species are involved in the lysosomal induction of oocyte degeneration for the reabsorption of phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves.

• Fisheries and Aquatic Sciences
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• 제4권1호
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• pp.18-24
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• 2001

Seasonal content changes of the three key nutrients for organisms, protein, lipid and glycogen, were analyzed for a whole year to delineate the seasonal energy strategy in pen shells, Atrina pectinata. Two metabolically important organs, the visceral mass and the posterior adductor muscle, were examined. Protein in the visceral mass rose in April and stayed at the level until June followed by the constant minimum value between August and November. The protein contents in the posterior adductor muscle increased sharply in April and again in July, followed by a gradual decline thereafter. Total lipid contents in the visceral mass gradually increased between January and May, and then slowly decreased until September since which a new weak increase was noticed. Lipid levels in the adductor muscle rapidly dropped in June and July. Glycogen contents in the visceral mass rapidly increased between February and June, followed by a drastic drop in July. This reduced visceral glycogen level was maintained up to September, and a gradual reduction ensued. Glycogen contents in the adductor muscle steadily but markedly increased from April reaching the maximum in August, and then slowly declined thereafter. These results suggest that an accelerated protein and lipid synthesis occurs in the gonad when the pen shell undergoes the ripe stage of gametogenesis, but the levels of these two nutrients decrease on spawning. With this gonadal process, regular protein synthesis and lipid storage in the posterior adductor muscle are temporarily arrested. The most important nutrient reserves that support gonad developmental cycles in a long term seem to be glycogen of the posterior adductor muscle.

• 한국작물학회지
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• 제46권4호
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• pp.272-278
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• 2001

To investigate of C and N metabolisms in response to phosphorus-deficient stress during regrowth of Italian ryegrass (Lolium multiflorum L.), C and N metabolites were analyzed at 0, 6, 12 and 24 days after defoliation. P-sufficient (control, +P) and P-absent (-P) nutrient solutions were applied from 7 days before defoliation, and continued for one cycle of 24 day-regrowth period. During 24 days of regrowth, dry matter of regrowing shoots and remaining tissues were not significantly different between +P and -P treatment. In remaining stubble, 70% to 91 % decline of the initial level (at day 0) in all C compounds occurred during the first 6 days of regrowth. Initial amounts of nitrate and amino acids in roots were significantly higher in the +P medium. Nitrate contents in stubble in the +P medium significantly decreased for the first 12 days and then rapidly recovered, while that of the -P medium continuously decreased until day 24. Amino acids in stubble in the P medium were continuously increased during the whole regrowth period. Soluble proteins in stubble in the +P medium also largely fell down (46.0% of the initial) for only the first 6 days, however the decline in the -P medium continued until day 12. In regrowing shoots, the accumulation of C compounds was significantly higher, while that of N compounds except amino acids was largely lower in the -P medium. These results showed a stimulation of carbohydrate synthesis and a compensatory utilization of organic reserves occurred to support regrowth under P-deficient condition.

• 한국환경농학회지
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• 제33권4호
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• pp.334-343
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• 2014

본 연구는 봄철 논습지에 도래하는 도요 물떼새류의 도래패턴과 서식지 이용 특성을 파악하고자 수행되었다. 조사는 한국 중서부지역에 위치한 아산만 일대의 농경지에서 2014년 4월 21일부터 5월 30일까지 2~3일 간격으로 총 18회 수행 되었다. 조사 기간 동안 관찰된 도요 물떼새류는 총 15종 7,852개체였다. 대상 종들의 시기별 도래 특성은 본답에 물을 대기 시작하는 4월 중반부터 관찰되었고 5월 초까지 지속적으로 종수와 개체수가 증가하는 경향이 나타났으며 5월 후반으로 가면서 종수와 개체수는 감소하였다. 농경지의 물리적 구조에 따른 서식지 이용 특성은 종별 차이가 나타났으며, 대부분의 종에서 본답과 논둑은 수로나 농로에 비해 선호성이 높게 나타났다. 본답의 미소서식지 선호성은 지역 농업인의 농업 관리에 의해 다양하게 나타났으며, 도요 물떼새류의 종별 서식지의 선호성 차이가 명확히 나타났다. 대부분 종은 무논의 본답 형태에서 관찰되었고, 써레질 후 5 cm 이하로 물을 얕게 댄 형태인 본답의 이용이 가장 높았다. 반면 물을 대지 않은 건답의 형태인 수확 후 추경한 형태는 이용을 하지 않았다. 결론적으로 봄철 논습지는 도요 물떼새류에게 중간 기착지로서 중요한 기능을 하는 것으로 나타났다.