• Title/Summary/Keyword: ATP

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Structural and Functional Analysis of Nitrogenase Fe Protein with MgADP bound and Amino Acid Substitutions (MgADP 결합 및 아미노산 치환 Nitrogenase Fe 단백질의 구조 및 기능 분석)

  • Jeong, Mi-Suk;Jang, Se-Bok
    • Journal of Life Science
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    • v.14 no.5
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    • pp.752-760
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    • 2004
  • The function of the [4Fe-4S] cluster containing iron (Fe-) protein in nitrogenase catalysis is to serve as the nucleotide-dependent electron donor to the MoFe protein which contains the sites for substrate binding and reduction. The ability of the Fe protein to function in this manner is dependent on its ability to adopt the appropriate conformation for productive interaction with the MoFe protein and on its ability to change redox potentials to provide the driving force required for electron transfer. The MgADP-bound (or off) conformational state of the nitrogenase Fe protein structure described reveals mechanisms for long-range communication from the nucleotide-binding sites to control affinity of association with the MoFe protein component. Two pathways, termed switches I and II, appear to be integral to this nucleotide signal transduction mechanism. In addition, the structure of the MgADP bound Fe protein provides the basis for the changes in the biophysical properties of the [4Fe-4S] observed when Fe protein binds nucleotides. The structures of the nitrogenase Fe protein with defined amino acid substitutions in the nucleotide dependent signal transduction pathways of the Switch I and Switch II have been determined by X-ray diffraction methods. These two pathways have been also implicated by site directed mutagenesis studies, structural analysis and analogies to other proteins that utilize similar nucleotide dependent signal transduction pathways. We have examined the validity of the assignment of these pathways in linking the signals generated by MgATP binding and hydrolysis to macromolecular complex formation and intermolecular electron transfer. The results provide a structural basis for the observed biophysical and biochemical properties of the Fe protein variants and interactions within the nitrogenase Fe protein-MoFe protein complex.

A Effective Ant Colony Algorithm applied to the Graph Coloring Problem (그래프 착색 문제에 적용된 효과적인 Ant Colony Algorithm에 관한 연구)

  • Ahn, Sang-Huck;Lee, Seung-Gwan;Chung, Tae-Choong
    • The KIPS Transactions:PartB
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    • v.11B no.2
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    • pp.221-226
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    • 2004
  • Ant Colony System(ACS) Algorithm is new meta-heuristic for hard combinational optimization problem. It is a population-based approach that uses exploitation of positive feedback as well as greedy search. Recently, various methods and solutions are proposed to solve optimal solution of graph coloring problem that assign to color for adjacency node($v_i, v_j$) that they has not same color. In this paper introducing ANTCOL Algorithm that is method to solve solution by Ant Colony System algorithm that is not method that it is known well as solution of existent graph coloring problem. After introducing ACS algorithm and Assignment Type Problem, show the wav how to apply ACS to solve ATP And compare graph coloring result and execution time when use existent generating functions(ANT_Random, ANT_LF, ANT_SL, ANT_DSATUR, ANT_RLF method) with ANT_XRLF method that use XRLF that apply Randomize to RLF to solve ANTCOL. Also compare graph coloring result and execution time when use method to add re-search to ANT_XRLF(ANT_XRLF_R) with existent generating functions.

The Acute Effect of Trimetazidine on the High Frequency Fatigue in the Isolated Rat Diaphragm Muscle

  • Emre, Mustafa;Karayaylali, Lbrahim;San, Mustafa;Demirkazik, Ayse;Kavak, Servet
    • Archives of Pharmacal Research
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    • v.27 no.6
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    • pp.646-652
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    • 2004
  • The objective of this study was to determine the acute effect of trimetazidine (TMZ) on the pre-fatigue, fatigue and post-fatigue contractile characteristics and tension-frequency relationships of isolated rat diaphragm muscle. Muscle strips were taken from the ventral-costal aspects of the diaphragm muscle of rats killed by decapitation. The muscle strips were suspended in organ baths containing Krebs solution, with a gas mixture of 95% $O_2$ and 5% $CO_2$ at $37^{\circ}C$ and pH 7.35-7.45. After determining the thermoregulation and optimum muscle length the muscles were subjected to direct supramaximal stimulation with 0.05 Hz frequency square pulses for periods of 0.5 msec to obtain control values. After adding $5{\times}10^{-6}{\;}and{\;}5{\times}10^{-5}$ M trimetazidine solution to the respective bath media, the contractile parameters of the muscles were recorded. The contractile parameters were also recorded for both the trimetazidine and tri-metazidine-free media after application of the high frequency fatigue protocols. Later, the tension-frequency relationship was determined by applying stimulating pulses of 10, 20, 50 and 100 Hz to the muscle strips. Whilst the twitch tension obtained from the $5{\times}10^{-6}{\;}and{\;}5{\times}10^{-5}$ M trimetazidine media showed numerical increases compared to that of the controls, these were not statistically significant (p>0.05). The contraction time exhibited a dose dependent increase (p<0.001), whilst the contraction and relaxation rates did not differ significantly. The isometric contraction forces obtained with the different stimulating frequencies showed a significant increase in the tetanic contraction only at 100 Hz (p<0.05). A comparison of the pre- and post-fatigue twitch tensions in the trimetazidine media showed the post- fatigue twitch tensions to be significantly higher than those of the pre-fatigue contraction forces (p<0.05). In the $5{\times}10^{-6}{\;}and{\;}5{\times}10^{-5}$ M trimetazidine media the increases in the post-fatigue contraction force were 22 and 30%, respectively. These results demonstrated that in isolated rat diaphragm muscle, TMZ significantly limited the mechanical performance decrease during fatigue. It is our opinion that trimetazidine contributed to the observed fatigue tolerance by eliminating the factors of fatigue, due to preservation of intracellular calcium homeostasis, provision of the ATP energy levels needed by ATPase dependent pumps and especially by keeping the intracellular pH within cer-tain limits.

Induces Vasodilatation of Rat Mesenteric Artery in vitro Mainly by Inhibiting Receptor-Mediated $Ca^{2+}$ -Influx and $Ca^{2+}$ -Release

  • Cao Yong-Xiao;Zheng Jian-Pu;He Jian-Yu;Li Jie;Xu Cang-Bao;Edvinsson Lars
    • Archives of Pharmacal Research
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    • v.28 no.6
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    • pp.709-715
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    • 2005
  • The purpose of this study was to investigate the effect of atropine on peripheral vasodilation and the mechanisms involved. The isometric tension of rat mesenteric artery rings was recorded in vitro on a myograph. The results showed that atropine, at concentrations greater than 1$\mu$M, relaxed the noradrenalin (NA)-precontracted rat mesenteric artery in a concentration-dependent manner. Atropine-induced vasodilatation was mediated, in part, by an endothelium-dependent mechanism, to which endothelium-derived hyperpolarizing factor may contribute. Atropine was able to shift the NA-induced concentration-response curve to the right, in a non-parallel manner, suggesting the mechanism of atropine was not mediated via the ${\alpha}_1$-adrenoreceptor. The $\beta$-adrenoreceptor and ATP sensitive potassium channel, a voltage dependent calcium channel, were not involved in the vasodilatation. However, atropine inhibited the contraction derived from NA and $CaCl_2$ in $Ca^{2+}$-free medium, in a concentration dependent manner, indicating the vasodilatation was related to the inhibition of extracellular $Ca^{2+}$ influx through the receptor-operated calcium channels and intracellular $Ca^{2+}$ release from the $Ca^{2+}$ store. Atropine had no effect on the caffeine-induced contraction in the artery segments, indicating the inhibition of intracellular $Ca^{2+}$ release as a result of atropine most likely occurs via the IP3 pathway rather than the ryanodine receptors. Our results suggest that atropine-induced vasodilatation is mainly from artery smooth muscle cells due to inhibition of the receptor-mediated $Ca^{2+}$-influx and $Ca^{2+}$-release, and partly from the endothelium mediated by EDHF.

Effect of Genotype on Whole-body and Intestinal Metabolic Response to Monensin in Mice

  • Fan, Y.K.;Croom, W.J.;Daniel, Linda;McBride, B.W.;Koci, M.;Havenstein, G.B.;Eisen, E.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.4
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    • pp.554-562
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    • 2006
  • Two lines of mice, M16 selected for rapid growth and a randomly selected control ICR as well as their reciprocal crosses were used to study the effects of genotype on whole-body energetics and intestinal responses to monensin. Six mice, eight weeks of age, from each line or reciprocal cross were assigned to one of two treatments, 1) drinking water containing 20 mmol/L monensin dissolved in 0.5% V/V ethanol, and 2) drinking water containing 0.5% V/V ethanol (control) for two weeks. After 11 days (age of 9 weeks and 4 days), whole-body $O_2$ consumption was measured. At the end of two weeks, jejunal $O_2$ consumption, intestinal tissue composition and histomorphometrics as well as the rate and efficiency of glucose absorption were estimated. In comparison with the control, monensin administration in drinking water resulted in less daily water intake (13.4 vs. 15.5 ml/mouse, p<0.01), less protein to DNA ratio of jejunal mucosa (5.41 vs. 6.01 mg/mg, p<0.05), lower villus width (88 vs. $100{\mu}m$, p<0.05), and less jejunal tissue $O_2$ consumption enhancement by alcohol (7.2 vs. 10.5%, p<0.01) in mice. Other than those changes, monensin had little (p>0.05) effect on variables measured in either line of mice or their reciprocal cross. In contrast, the M16 line, selected for rapid growth, as compared to the ICR controls or the reciprocal crosses, had less initial (pre-monensin treatment) whole-body $O_2$ consumption per gram of body weight (1.68 vs. $2.11-2.34{\mu}mol/min{\cdot}g$ BW, p<0.01) as compared to the ICR and reciprocal crosses. In addition, the M16 mice exhibited greater growth (412 vs. 137-210 mg/d, p<0.05), better feed efficiency (41.7 vs. 19.9-29.3 mg gain/g feed, p<0.05), shorter small intestines adjusted for fasted body weight (1.00 vs. 1.22-1.44 cm/g FBW, p<0.05), wider villi (109 vs. $87-93{\mu}m$, p<0.05), more mature height of enterocytes (28.8 vs. $24.4-25.1{\mu}m$, p<0.05) and a lower rate (91 vs. $133-145{\eta}mol\;glucose/min{\cdot}g$ jejunum, p<0.05) and less energetic efficiency (95 vs. $59-72{\eta}mol$ ATP expended/${\eta}mol$ glucose uptake, p<0.05) of glucose absorption compared to the ICR line and the reciprocal cross. Monensin had little (p>0.05) effect on whole-body $O_2$ consumption and jejunal function, whilst selection for rapid growth resulted in an apparent down-regulation of intestinal function. These data suggest that genetic selection for increased growth does not result in concomitant changes in intestinal function. This asynchrony in the selection for production traits and intestinal function may hinder full phenotypic expression of genotypic growth potential.

Proteomic Analysis and the Antimetastatic Effect of N-(4methyl)phenyl-O-(4-methoxy) phenyl-thionocarbamate-Induced Apoptosis in Human Melanoma SK-MEL-28 cells

  • Choi Su-La;Choi Yun-Sil;Kim Young-Kwan;Sung Nack-Do;Kho Chang-Won;Park Byong-Chul;Kim Eun-Mi;Lee Jung-Hyung;Kim Kyung-Mee;Kim Min-Yung;Myung Pyung-Keun
    • Archives of Pharmacal Research
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    • v.29 no.3
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    • pp.224-234
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    • 2006
  • We employed human SK-MEL-28 cells as a model system to identify cellular proteins that accompany N-(4-methyl)phenyl-O-(4-methoxy)phenyl-thionocarbamate (MMTC)-induced apoptosis based on a proteomic approach. Cell viability tests revealed that SK-MEL-28 skin cancer cells underwent more cell death than normal HaCaT cells in a dose-dependent manner after treatment with MMTC. Two-dimensional electrophoresis in conjunction with matrixassisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analysis or computer matching with a protein database further revealed that the MMTC-induced apoptosis is accompanied by increased levels of caspase-1, checkpoint suppressor-1, caspase-4, NF-kB inhibitor, AP-2, c-Jun-N-terminal kinase, melanoma inhibitor, granzyme K, G1/S specific cyclin D3, cystein rich protein, Ras-related protein Rab-37 or Ras-related protein Rab-13, and reduced levels of EMS (oncogene), ATP synthase, tyrosine-phosphatase, Cdc25c, 14-3-3 protein or specific structure of nuclear receptor. The migration suppressing effect of MMTC on SK-MEL-28 cell was tested. MMTC suppressed the metastasis of SK-MEL-8 cells. It was also identified that MMTC had little angiogenic effect because it did not suppress the proliferation of HUVEC cell line. These results suggest that MMTC is a novel chemotherapeutic and metastatic agents against the SK-MEL-28 human melanoma cell line.

Identification of Genes Modulated by High Extracellular Calcium in Coculture of Mouse Osteoblasts and Bone Marrow Cells by Oligo Chip Assay

  • Kim, Hyung-Keun;Song, Mi-Na;Jun, Ji-Hae;Woo, Kyung-Mi;Kim, Gwan-Shik;Baek, Jeong-Hwa
    • International Journal of Oral Biology
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    • v.31 no.2
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    • pp.53-65
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    • 2006
  • Calcium concentration in the bone resorption lacunae is high and is in the mM concentration range. Both osteoblast and osteoclast have calcium sensing receptor in the cell surface, suggesting the regulatory role of high extracellular calcium in bone metabolism. In vitro, high extracellular calcium stimulated osteoclastogenesis in coculture of mouse osteoblasts and bone marrow cells. Therefore we examined the genes that were commonly regulated by both high extracellular calcium and $1,25(OH)_2vitaminD_3(VD3)$ by using mouse oligo 11 K gene chip. In the presence of 10 mM $[Ca^{2+}]e$ or 10 nM VD3, mouse calvarial osteoblasts and bone marrow cells were co-cultured for 4 days when tartrate resistant acid phosphatase-positive multinucleated cells start to appear. Of 11,000 genes examined, the genes commonly regulated both by high extracellular calcium and by VD3 were as follows; 1) the expression of genes which were osteoclast differentiation markers or were associated with osteoclastogenesis were up-regulated both by high extracellular calcium and by VD3; trap, mmp9, car2, ctsk, ckb, atp6b2, tm7sf4, rab7, 2) several chemokine and chemokine receptor genes such as sdf1, scya2, scyb5, scya6, scya8, scya9, and ccr1 were up-regulated both by high extracellular calcium and by VD3, 3) the genes such as mmp1b, mmp3 and c3 which possibly stimulate bone resorption by osteoclast, were commonly up-regulated, 4) the gene such as c1q and msr2 which were related with macrophage function, were commonly down-regulated, 5) the genes which possibly stimulate osteoblast differentiation and/or mineralization of extracellular matrix, were commonly down-regulated; slc8a1, admr, plod2, lox, fosb, 6) the genes which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were commonly up-regulated; s100a4, npr3, mme, 7) the genes such as calponin 1 and tgfbi which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were up-regulated by high extracellular calcium but were down-regulated by VD3. These results suggest that in coculture condition, both high extracellular calcium and VD3 commonly induce osteoclastogenesis but suppress osteoblast differentiation/mineralization by regulating the expression of related genes.

Taste Characteristics and Functionality of Two Stage Enzyme Hydrolysate from Low-Utilized Longfinned Squid (창오징어 2단 효소분해엑스분의 정미특성 및 기능성)

  • 오광수
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.5
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    • pp.782-786
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    • 2001
  • The taste characteristics and functionality of low-utilized small longfinned squid as affected by two stage enzyme hydrolysis were examined. In taste active-components, total free amino acid contents in hot-water and autolytic extract, two stage enzyme hydrolysate (TSEH) of longfinned squid were 2,792.5 mg%, 8,393.8 mg% and 9,186.1 mg%, respectively. The major free amino acids were Pro, Leu, Glu, Tau, Lys, Arg, Phe, Val and Ile. As for quarternary ammonium bases, betaine was the principal component (593.8 mg%) and also contents of TMAO, AMP in longfinned squid TSEH were 234.8% mg% and 51.0 mg%, respectively. The major inorganic ions in TSEH were Na(874.0 mg%), K (398.2 mg%), Cl (1,213.1 mg%) and PO$_4$(995.9 mg%). From the results in sensory tests, TSEH was superior to other extracts on the aspects of taste characteristics such as umami intensity, sweetness, taste harmony and transparency of extract. Also TSEH of longfinned squid revealed very higher Angiotensin-I converting enzyme inhibition ratio (92.1%) than those of hot-water and autolytic extract.

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Mechanism of Relaxation of Rat Aorta by Scopoletin; an Active Constituent of Artemisia Capillaris

  • Kwon Eui Kwang;Jin Sang Sik;oChoi Min H;Hwang Kyung Taek;Shim Jin Chan;Hwang Il Taek;Han Jong Hyun
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.16 no.2
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    • pp.389-396
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    • 2002
  • In the present work, we examined the mechanism of vasorelaxant effect of scopoletin, an active constituent of Artemisia capillaris on rat thoracic descending aortic rings. Scopoletin induced a concentration-dependent relaxation in rat thoracic descending aortic rings pre-contracted with phenylephrine (EC/sub 50/ = 238.94±37.4 μM), while it was less effective in rat thoracic descending aortic rings precontracted with high potassium solution (KCI 30 mM). Vasorelaxation by scopoletin was significantly inhibited after endothelial removal, but recovered at high concentration. Pretreatment of rat thoracic descending aortic rings with N/sup G/-nitro-L-arginine (100 μM), a nitric oxide synthase inhibitor, and atropine (1 μM), a muscarinic receptor antagonist, significantly inhibited scopoletin-induced relaxation of rat thoracic descending aortic rings. Neither indomethacin (3 μM), an inhibitor of cydooxygenase, nor propranolol (1 μM), a β -adrenoceptor antagonist, modified the effect of scopoletin. The combination of N/sup G/ -nitro-L-arginine (100 μ M) and miconazole (10 μ M), an inhibitor of cytochrome P 450, did not modify the effect of scopoletin, when compared with pretreatment with N/sup G/-nitro-L-arginine(100 μM) alone. Vasorelaxant effect of scopoletin was inverted by pretreatment with diltiazem (10 μM), a Ca/sup 2+/-channel blocker, at low concentration, while restored at high concentration. Apamin (K/sub ca/-channel blocker, 1 μM), 4-aminopyridine (4-AP, K/sub v/-channel blocker, 1 mM), and tetrodotoxin (TTX, Na/sup +/-channel blocker 1 μM) potentiated the vasorelaxant effect of scopoledn, but glibendamide (K/sub ATP/-channel blocker, 10 μM), tetraetylammonium(TEA, non-selective K-channel blocker, 10 mM) did not affect the relaxation of scopoletin. Free radical scavengers (TEMPO, catalase, mannitol) did not modify vascular tone. These results suggest that nitric oxide, Ca/sup 2+/ -channels play a role in endothelium-dependent relaxations to scopoletin in rat aortas, that apamin, 4-AP, TTX but not glibenclamide, TEA potentiated relaxation to scopoletin mediated by these channels, and that free radicals do not concern to the vasorelaxant effect of scopoletin.

Manipulation of Tissue Energy Metabolism in Meat-Producing Ruminants - Review -

  • Hocquette, J.F.;Ortigues-Marty, Isabelle;Vermorel, M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.5
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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.