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

• Journal of Microbiology and Biotechnology
• /
• 제17권3호
• /
• pp.496-510
• /
• 2007

This paper describes the use of a discrete mathematical model to represent the basic mechanisms of regulation of the bacteria E. coli in batch fermentation. The specific phenomena studied were the changes in metabolism and genetic regulation when the bacteria use three different carbon substrates (glucose, glycerol, and acetate). The model correctly predicts the behavior of E. coli vis-a-vis substrate mixtures. In a mixture of glucose, glycerol, and acetate, it prefers glucose, then glycerol, and finally acetate. The model included 67 nodes; 28 were genes, 20 enzymes, and 19 regulators/biochemical compounds. The model represents both the genetic regulation and metabolic networks in an integrated form, which is how they function biologically. This is one of the first attempts to include both of these networks in one model. Previously, discrete mathematical models were used only to describe genetic regulation networks. The study of the network dynamics generated 8 $(2^3)$ fixed points, one for each nutrient configuration (substrate mixture) in the medium. The fixed points of the discrete model reflect the phenotypes described. Gene expression and the patterns of the metabolic fluxes generated are described accurately. The activation of the gene regulation network depends basically on the presence of glucose and glycerol. The model predicts the behavior when mixed carbon sources are utilized as well as when there is no carbon source present. Fictitious jokers (Joker1, Joker2, and Repressor SdhC) had to be created to control 12 genes whose regulation mechanism is unknown, since glycerol and glucose do not act directly on the genes. The approach presented in this paper is particularly useful to investigate potential unknown gene regulation mechanisms; such a novel approach can also be used to describe other gene regulation situations such as the comparison between non-recombinant and recombinant yeast strain, producing recombinant proteins, presently under investigation in our group.

• 생명과학회지
• /
• 제33권3호
• /
• pp.295-303
• /
• 2023

면역 체계와 대사 체계는 항상성을 유지하는데 중요한 요소이다. 면역 반응과 대사 조절은 연관성이 높아, 정상적인 대사가 교란되면 대사 질환이 발생하며, 면역 반응에도 변화가 발생하였다. 마찬가지로, 비만은 면역 반응과 높은 관련이 있다. 에너지 대사의 불균형으로 발생하는 비만은 인슐린 저항성, 제2형 당뇨병, 지방간 질환, 동맥경화증, 고혈압 등의 대사 질환과 관련이 있다. 알려진 바로는, 비만은 낮은 수준의 염증이 만성화된 상태가 특징이다. 비만 환경에서, 면역세포의 미세 환경은 대식세포, 자연살해세포, T세포 같은 면역세포의 독특한 활성화 표현형에 의해 염증성이 되었다. 또한, 면역 세포는 세포 간의 기전, 사이토카인을 매개하는 기전을 통해 상호작용하여 비만으로 인한 염증 반응을 강화한다. 이러한 현상은 기존의 췌장 리파아제나 알파-아밀라아제 같은 체내 효소의 억제나 지방전구세포의 분화를 억제를 표적으로 하는 일반적인 비만의 약리학적 치료 외에 면역세포 활성화 조절을 표적으로 하는 비만의 약리학적 치료 전략을 시사한다. 본 논문에서는 대식세포, 자연살해세포, T세포의 활성화 표현형과 비만 환경 내이들의 양상에 대해 정리하였다. 또한, 본 논문에서는 현재까지 확인된 면역세포의 활성화 조절을 통한 비만을 완화하는 약리학적 물질에 대해서 정리하였다.

• 생명과학회지
• /
• 제34권7호
• /
• pp.465-475
• /
• 2024

Lactiplantibacillus plantarum K9은 굼벵이에서 분리된 다양한 생리활성물질에 기인하여 프로바이오틱스 균주로 활용 가능한 유산균이다. L. plantarum K9 유전체 분석결과로써 박테리아 염색체와 3 plasmid가 존재하는 것으로 나타났다. L. plantarum K9의 핵심 대사경로 분석 결과 해당과정, 오탄당대사(pentose phosphate pathway)는 정상적으로 수행되는 것으로 나타났다. 그러나 포도당신생합성과 ED pathway의 핵심 효소인 fructose-1,6-bisphosphatase (EC: 3.1.3.11)와 6-phosphogluconate dehydratase (EC: 4.2.1.12) / 2-keto-de- oxy-6-phosphogluconate (KDPG) aldolase (EC: 4.2.1.55)가 각각 결여되어 있기 때문에 포도당신생합성과 ED pathway는 수행하지 못하는 것으로 제의된다. 또한, TCA 회로에서 fumarate 및 malate를 형성하는 일부 효소만 존재하는 반면에 나머지 TCA 회로에 연관되는 효소들이 모두 결여되어 있었기 때문에 TCA 회로는 진행되지 못하는 것으로 추정되었다. 산화적 전자전달계는 NADH dehydrogenase complex I과 cytochrome reductase complex IV에 해당하는 요소들을 보유하고 있기 때문에 class IIB 타입(bd-type)의 전자전달시스템을 수행할 것으로 예측되었다. 종합적으로, L. plantarum K9은 lactic acid 동형발효를 수행하며, 포도당신생합성 및 오탄당대사가 가능하며, class IIB 타입(bd-type) 산화적 전자전달시스템에 의해 에너지 대사를 수행하는 것으로 제의된다. 따라서, L. plantarum K9은 다른 유산균주에 비교하여 lactic acid 생성량이 비교적 높아 생리활성도가 우수할 것으로 제의된다. 다른 한편으로, L. plantarum K9은 산화적 전자전달이 가능한 것으로 추정되어 산소에 대한 내성이 높아서 배양 특성이 양호하여 프로바이틱스로써 활용가능성이 높은 것으로 제의된다.

• 한국식품저장유통학회지
• /
• 제14권3호
• /
• pp.323-327
• /
• 2007

본 연구는 PME 처리가 미생물의 생리변화에 미치는 영향을 중심으로 PME의 항균작용을 규명하기 위해서 소수성 분획과 친수성 분획으로 분리하고, 공시균주를 사용하여 미생물의 성장 및 에너지대사 관련효소의 활성에 미치는 영향을 조사하였다. 매실추출물 분획별 항균활성은 변패미 생물인 C. fragariae를 대상으로 paper disk법으로 관찰하였다. 총 추출물(PME)의 소수성 분획은 C. fragariae의 성장을 저해하기는 하나 그 효과가 총 추출물 보다 약한 반면, 친수성 분획은 총 추출물보다 더 뚜렷한 저해 효과를 보였다. 이와 같은 매실추출물의 분획별 미생물의 생육억제효과는 다른 식품부패미생물 군에서도 동일한 패턴을 보여 주었다. B. cereus, E, coli 및 Fusarium sp.에 대해서는 PME의 친수성 분획은 뚜렷한 항균효과를 보여 주었으며, 총 추출물 또한, 항균력을 나타내었으나, 소수성 분획은 낮은 항균력을 보여 본 실험의 공시균주인 C. fragariae에 대한 매실추출물의 분획별 항균효과를 확인할 수 있었다. 매실 추출물첨가 배지 상에서 C. fragariae의 생육이 크게 억제된다는 실험결과를 토대로 매실추출물의 항균활성물질이 미생물 세포내의 효소계의 효소활성을 저해에 기인한 것인가를 알아보기 위하여, 에너지생성대사에 관여하는 몇 가지 효소 활성(glucose-6-phosphate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, hexokinase)에 미치는 매실추출물의 영향을 살펴보았다. 이 결과로 매실추출물은 총 추출물 및 친수성 분획이 일부 에너지 생성대사 효소계의 효소활성에 영향을 미치는 것으로 나타나(12-40%), 매실 추출물의 항균물질이 세포내로 침투되어 membrane에 존재하는 효소의 활성을 억제하는 것으로 추정할 수 있었다. 본 연구결과를 토대로 미루어, 매실추출물의 항균 작용은 세포내 에너지 생성에 관여하는 효소의 활성을 감소시키는 현상에 기인하는 것으로 추정되었다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제26권4호
• /
• pp.263-275
• /
• 2022

There is a paucity of detailed data related to the effect of senescence on the mitochondrial antioxidant capacity and redox state of senescent human cells. Activities of TCA cycle enzymes, respiratory chain complexes, hydrogen peroxide (H₂O₂), superoxide anions (SA), lipid peroxides (LPO), protein carbonyl content (PCC), thioredoxin reductase 2 (TrxR2), superoxide dismutase 2 (SOD2), glutathione peroxidase 1 (GPx1), glutathione reductase (GR), reduced glutathione (GSH), and oxidized glutathione (GSSG), along with levels of nicotinamide cofactors and ATP content were measured in young and senescent human foreskin fibroblasts. Primary and senescent cultures were biochemically identified by monitoring the augmented cellular activities of key glycolytic enzymes including phosphofructokinase, lactate dehydrogenase, and glycogen phosphorylase, and accumulation of H₂O₂, SA, LPO, PCC, and GSSG. Citrate synthase, aconitase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and complex I-III, II-III, and IV activities were significantly diminished in P25 and P35 cells compared to P5 cells. This was accompanied by significant accumulation of mitochondrial H₂O₂, SA, LPO, and PCC, along with increased transcriptional and enzymatic activities of TrxR2, SOD2, GPx1, and GR. Notably, the GSH/GSSG ratio was significantly reduced whereas NAD⁺/NADH and NADP⁺/NADPH ratios were significantly elevated. Metabolic exhaustion was also evident in senescent cells underscored by the severely diminished ATP/ADP ratio. Profound oxidative stress may contribute, at least in part, to senescence pointing at a potential protective role of antioxidants in aging-associated disease.

• 한국식품저장유통학회지
• /
• 제30권3호
• /
• pp.526-537
• /
• 2023

본 실험에서는 산마늘 추출물의 in vitro 항산화 및 in vitro 생리활성 효능평가를 진행하였다. 산마늘 추출물은 페놀성 화합물과 플라보노이드 화합물을 함유하고 있으며, ABTS, DPPH 라디칼 소거 활성 등을 나타내었다, 특히, 산마늘 추출물은 우수한 알코올 대사 관련 효소 활성을 나타내었으며 더불어, HepG2 세포에서 에탄올로 유도된 스트레스에 대해 세포 생존율을 유의적으로 증가시켰으며, 활성 산소종의 생성을 효과적으로 감소시켰다. 그리고 산마늘 물 및 60% 에탄올 추출물은 에탄올로 세포독성이 유도된 간세포에서 BCl-2, BAX 및 pro-caspase-3의 발현량을 개선함으로써 세포사멸을 억제하는 것으로 확인되었다.

• Journal of Microbiology
• /
• 제44권5호
• /
• pp.492-501
• /
• 2006

In this study, we attempted to characterize the physiological response to oxidative stress by heat shock in Saccharomyces cerevisiae KNU5377 (KNU5377) that ferments at a temperature of $40^{\circ}C$. The KNU5377 strain evidenced a very similar growth rate at $40^{\circ}C$ as was recorded under normal conditions. Unlike the laboratory strains of S. cerevisiae, the cell viability of KNU5377 was affected slightly under 2 hours of heat stress conditions at $43^{\circ}C$. KNU5377 evidenced a time-dependent increase in hydroperoxide levels, carbonyl contents, and malondialdehyde (MDA), which increased in the expression of a variety of cell rescue proteins containing Hsp104p, Ssap, Hsp30p, Sod1p, catalase, glutathione reductase, G6PDH, thioredoxin, thioredoxin peroxidase (Tsa1p), Adhp, Aldp, trehalose and glycogen at high temperature. Pma1/2p, Hsp90p and $H^+$-ATPase expression levels were reduced as the result of exposure to heat shock. With regard to cellular fatty acid composition, levels of unsaturated fatty acids (USFAs) were increased significantly at high temperatures ($43^{\circ}C$), and this was particularly true of oleic acid (C18:1). The results of this study indicated that oxidative stress as the result of heat shock may induce a more profound stimulation of trehalose, antioxidant enzymes, and heat shock proteins, as well as an increase in the USFAs ratios. This might contribute to cellular protective functions for the maintenance of cellular homeostasis, and may also contribute to membrane fluidity.

• Preventive Nutrition and Food Science
• /
• 제7권3호
• /
• pp.332-345
• /
• 2002

It is a recent observation that about 80 per cent of the body's immune system is localized in the gastrointestinal tract. This explains to a large extent why eating right is important for the modulation the immune response and prevention of disease. In addition it is increasingly recognized that the body has an important digestive system also in the lower gastrointestinal tract where numerous important substances are released by microbial enzymes and absorbed. Among these substances are short chain fatty acids, amino acids, various carbohydrates, poly-amines, growth factors, coagulation factors, and many thousands of antioxidants, not only traditional vitamins but numerous flavonoids, carotenoids and similar plant- and vegetable produced antioxidants. Also consumption of health-promoting bacteria (probiotics) and vegetable fibres (prebiotics) from numerous sources are known to have strong health-promoting influence. It has been calculated that the intestine harbours about 300,000 genes, which is much more than the calculated about 60,000 for the rest of the human body, indicating a till today totally unexpected metabolic activity in this part of the GI tract. There are seemingly several times more active enzymes in the intestine than in the rest of the body, ready to release hundred thousand or more of substances important for our health and well-being. In addition do the microbial cells produce signal molecules similar to cytokines but called bacteriokines and nitric oxide, with provide modulatory effects both on the mucosal cells, the mucosa- associated lymphoid system (MALT) and the rest of the immune system. Identification of various fermentation products, and often referred to as synbiotics, studies of their role in maintaining health and well-being should be a priority issue during the years to come.

• Environmental Analysis Health and Toxicology
• /
• 제18권2호
• /
• pp.69-76
• /
• 2003

Effects of ambient nitrite, NO$_2$$\^$-/, at 1, 3, 10 and 30 mg/1, on the changes of plasma nitrite/nitrate and on hepatic drug - metabolizing enzyme activity were examined in the juvenile Israeli carp, Cyprinus carpio. When the fish were exposed to 1 and 3 mg/1 NO$_2$$\^$-/, there was an exposure duration-dependent increase in plasma NO$_2$$\^$-/ over the 96-hr period reaching 6∼7 fold excess the ambient concentration. In the fish exposed to 10 mg/1, a plateau concentration of less than 2-fold of the environment was attained in 12 hr. With 30 mg/1, however, the maximal plasma NO$_2$$\^$-/ was 41.25 mg/1 at 12 hr followed by a gradual decline. There was a concentration-dependent increase in methemoglobin (metHb) level in all NO$_2$$\^$-/ -exposed groups and a significant decrease in hematocrit value in 30 mg/l group after 96-hr exposure. Apart from the blunted increase in plasma NO$_2$$\^$-/ with higher NO$_2$$\^$-/ (10 and 30 mg/1) exposure, the ratio of plasma NO$_3$$\^$-/ to NO$_2$$\^$-/ was signifirantly higher in these groups compared to 1 and 3 mg/1. The imbalance in the plasma NO$_3$$\^$-//NO$_2$$\^$-/ at higher NO$_2$$\^$-/ exposure suggests a possible accelerated conversion of NO$_2$$\^$-/ to NO$_3$$\^$-/. Nitrite exposure did not affect the hepatic drug-metabolic activities in juvenile Israeli carp. All these data indicate that disposition of NO$_2$- differ depending upon exposed concentration and that metHb production may not be the exclusive toxic mechanism in carp.