• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1196-1203
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• 2010

In the present work, methanethiol and dimethyldisulfide were investigated as sulfur sources for methionine synthesis in Corynebacterium glutamicum. In silico pathway analysis predicted a high methionine yield for these reduced compounds, provided that they could be utilized. Wild-type cells were able to grow on both methanethiol and dimethyldisulfide as sole sulfur sources. Isotope labeling studies with mutant strains, exhibiting targeted modification of methionine biosynthesis, gave detailed insight into the underlying pathways involved in the assimilation of methanethiol and dimethyldisulfide. Both sulfur compounds are incorporated as an entire molecule, adding the terminal S-$CH_3$ group to O-acetylhomoserine. In this reaction, methionine is directly formed. MetY (O-acetylhomoserine sulfhydrylase) was identified as the enzyme catalyzing the reaction. The deletion of metY resulted in methionine auxotrophic strains grown on methanethiol or dimethyldisulfide as sole sulfur sources. Plasmid-based overexpression of metY in the ${\Delta}$metY background restored the capacity to grow on methanethiol or dimethyldisulfide as sole sulfur sources. In vitro studies with the C. glutamicum wild type revealed a relatively low activity of MetY for methanethiol (63 mU/mg) and dimethyldisulfide (61 mU/mg). Overexpression of metY increased the in vitro activity to 1,780 mU/mg and was beneficial for methionine production, since the intracellular methionine pool was increased 2-fold in the engineered strain. This positive effect was limited by a depletion of the metY substrate O-acetylhomoserine, suggesting a need for further metabolic engineering targets towards competitive production strains.

• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.355-358
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• 1986

The effects of cobalt chloride, methionine, and various carbon sources on the sisomicin production by M. inyoensis NRRL 3292 were investigated. It was found that both cobalt chloride and methionine exerted a greater stimulatory effect on sisomicin formation. Kinetic studies with various carbon sources revealed thai polysaccharide such as starch or dextrin was found io be better than glucose for sisomicin production Moreover, the relatively low concentration of dissolved carbon dioxide was one of the most important factors In accelerating sisomicin production during idiophase.

• Korean Journal of Poultry Science
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• v.22 no.1
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• pp.43-54
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• 1995

Effects of dietary protein sources and their amino acid compositions on the liver and plasma cholesterol levels in growing Single Comb white Leghorn male chicks were studied. A diet containing isolated soy protein (21% cp) was supplemented with 0.5% DL-methionine and 0.3% L-glycine. and another diet containing casein(21% cp) was supplemented with 1.5% L-arginine HCl, 0.4% DL-methionine. and 1.0% L-glycine. Plasma cholesterol level was markedly lower in groups force-fed the diets containing either soy protein or casein supplemented with amino acids compared to those found in birds fed corresponding diets without amino acids supplementation. The cholesterol lowering effect of the casein diet. when balanced with various supplemental amino acids appeared to be due to arginine instead of methionine or glycine. It is likely that amino acid balance rather than the composition of a specific amino acid is one of the major factors determining the effect of dietary protein sources on the blood cholesterol levels in chicks.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.1003-1010
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• 2005

A study consisting of 3 trials was designed to assess the relative biological efficacy of DL-methionine (DL-Met) in comparison to liquid methionine hydroxy analogue (MHA-FA) in growing pigs. In trial I a basal diet was supplemented with three graded levels of DL-methionine (0.25, 0.50 and 0.75 g/kg) or liquid MHA-FA (0.0285, 0.0570 and 0.0855 g/kg) on equimolar basis. The basal diet contained 18.3% CP, 0.22% Met and 0.51% Met+Cys, which is below the methionine requirement for weaned pigs between 10 and 20 kg BW according to NRC (1998) but adequate in all other essential nutrients and energy. Using an exponential model, the efficacy of the two methionine sources was estimated from nitrogen retention data obtained in 42 piglets with an initial BW between 11.0 kg (Exp. 1) and 11.7 kg (Exp. 2). In trials II and III, with a total of 192 and 96 pigs, and with an initial BW of 10.6 and 21 kg, respectively, growth response criteria were assessed to determine if in agreement with previous studies in pigs and poultry a biological effectiveness of about 65% on average could be confirmed for liquid MHA-FA in comparison to DL-met. Based on N-retention (trial I) the biological efficacy of liquid MHA-FA on a weight-to-weight basis was calculated to be 62% relative to DL-met. Basically, these results were confirmed using growth response criteria as measures; the results of trial II and III revealed no significant differences in growth performance and feed conversion between treatments indicating that 100 parts of liquid MHA-FA can be replaced by 65 parts of DL-met.

• Archives of Pharmacal Research
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• v.2 no.2
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• pp.79-83
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• 1979

Using cephalosporium acremonium ATCC 14553, we studied on the important factors in fermentation. Those factors were :carbon and nitrogen sources, methionine effect, absorbent effect, fermentation variables in a batch fermentation variables in a batch fermentation, effect of reuse of its cellular biomass as a reusable nutrient, and 2, 4-dinitrophenol effect on cephalosprin C production.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.279-288
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• 1994

Three experiments were conducted with female Japanese Saanen goats to investigate the effects of rumen protected methionine (RPMet) on N utilization and whole-body protein turnover. Whole-body leucine flux from which whole-body protein turnover rates were derived was measured by primed- continuous infusion of L-[$^{15}N$] leucine in combination with gas chromatography-mass spectrometry. Throughout the experiments RPMet was added to a diet to supply 1.5 g DL-methionine per goat per day. Irrespective of the major N sources (i.e., protein or urea) in the diet, both N deposition and whole-body protein synthesis were increased (p<0.05), and urinary N excretion was decreased (p<0.05) by supplementing with RPMet, but not by supplementing with methionine. It was concluded, therefore, that under the present experimental conditions, the RPMet supplement was efficiently bypassed to result in enhanced body protein synthesis of the goat.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1348-1354
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• 2008

Two inorganic (zinc sulfate and zinc oxide) and three organic (zinc acetate, zinc-methionine, and zinc-lysine) zinc sources were evaluated for their effects on the performance and carcass characteristics of broiler chicks. The birds were randomly assigned to one control (non-supplemented) and 15 treatment (supplemented) groups consisting of four replicates of 10 chicks each in a $5{\times}3$ factorial arrangement of treatments (five zinc sources and three supplemental zinc levels). Birds were kept in floor pens in a temperature-controlled room from 1 to 42 d of age and fed a non-supplemented basal diet (control) or the basal diet supplemented with 40, 80 or 120 mg/kg of Zn as mentioned sources. Dietary zinc source had considerable effect on feed intake in all experimental periods. Increasing Zn level from 80 to 120 mg/kg decreased the average feed intake in the growth stage (p<0.01) and also in the entire experimental period (p<0.001). Similarly, the average daily gain during the entire trial period was affected by the type of Zn source (p<0.001) and supplemental level (p<0.01). One degree of freedom contrast comparisons showed that the inclusion of organic zinc sources into the diets caused significant increases in feed intake and body gain when compared with inorganic counterparts. Except in wk 1, dietary supplementation with organic sources improved (p<0.05) feed conversion ratio; FCR values were not affected by dietary Zn source or supplementation level. Breast meat yield increased with supplemental levels of organic Zn sources; however, other carcass parameters were not affected by dietary Zn source. On the other hand, organic versus inorganic zinc supplementation caused a significant increase in liver, breast and carcass weight percentages. The present findings suggest that supplemental levels of organic Zn compounds had beneficial effects on broiler performance, and Zn requirements can be reduced using these feed supplements in poultry rations.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.184-187
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• 2008

S-Adenosyl-L-methionine (SAM) is an important metabolic intermediate in living organisms and participates in many reactions as a methyl group donor. SAM has been used as a dietary supplement and is proposed to have beneficial effects on the liver and brain. The aim of this study was to find lactic acid bacteria with high SAM-producing ability to be used as SAM enhancing probiotics. We used high performance liquid chromatography (HPLC) to quantify the amount of SAM produced, and found that Bifidobacterium bifidum BGN4 produced a significantly higher amount of SAM than other Bifidobacterium or Lactobacillus strains. The effect of various carbon and nitrogen sources on SAM production was examined. This study confirmed that Bifidobacterium may be utilized as a source of SAM in the functional food industry.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1506-1515
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• 2008

Two feeding trials were conducted to assess the relative bioavailability (RBV) of methionine hydroxy analogue calcium salt (MHA-Ca) in comparison to DL-methionine (DL-Met). Male Ross 308 (1-38 days) and Cobb 500 chickens (1-42 days) were used in studies 1 and 2, respectively. Experimental diets based on wheat and soybean meal or sorghum and soybean meal were fed during three phases. In both experiments graded levels of DL-Met and MHA-Ca were supplemented to Met+Cys deficient basal diets. Additionally, in experiment 1, increasing levels of a DL-Met preparation diluted with corn starch to 65% purity (DL-Met65) were supplemented. Birds were kept in floor pens and feed and water were available ad libitum. Body weights and feed consumption were recorded at the beginning and end of the experimental periods and weight gain and feed efficacy were computed subsequently. At the end of the experiments, a number of birds were slaughtered for carcass evaluation (dressing percentage, breast meat yield). Dose response data were analysed by both ANOVA and nonlinear common plateau asymptotic regression. In both experiments birds responded significantly to increasing levels of either methionine source. However, RBV of MHA-Ca compared to DL-Met was markedly (in many cases significantly) below 84%, the value which would have been expected from MHA-Ca's chemical characteristics. Excluding some extremely low RBV figures of trial 2, RBV of MHA-Ca averaged to about 63% in relation to DL-Met. In addition, supplementation of DL-Met65 allowed confirmation of nonlinear common plateau asymptotic regression to be suitable to determine RBV.

• The Korean Journal of Food And Nutrition
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• v.24 no.2
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• pp.166-172
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• 2011

This study was conducted to assess food safety knowledge of college students according to mass-media reports. To accomplish this, a survey was conducted to investigate the reliability, of primary mass-media sources on Bovine Spongiform Encephalopathy(BSE) as well as the preferences of college students. The most common sources of media consumed by male and female students were terrestrial television(TV)(60%), the internet(21%), and newspapers(11%) and terrestrial TV(60%), newspapers (18%), and the internet(17%), respectively. The preferences for media of major and non-major students were terrestrial TV(64%), newspapers(17%), and the internet(14%) and terrestrial TV(51%), the internet(22%), and newspapers(19%), respectively. The reliability of media as viewed by male students were as follows: terrestrial TV(53%) and the internet(40%), whereas for female students, these values were terrestrial TV(55%) and the internet(37%). The reliability of media as viewed by major and non-major students was as follows: terrestrial TV(67%) and the internet(28%), and terrestrial TV(44%) and the internet(44%), respectively. In the case of male students, the primary sources for information regarding BSE were terrestrial TV(54%) and the internet(38%), whereas for female students, the primary sources were terrestrial TV(57%) and internet (37%). In the case of major students, the primary sources for information regarding BSE were terrestrial TV(52%) and the Internet(40%), and for non-major students, the internet(47%) and terrestrial TV(39%). Both male and female students were found to have less knowledge regarding prions, SRM(Specified Risk Materials), MM(methionine-methionine) type genes, and cow above 30 months associated with BSE compared to the other factors associated with this disease. The BSE-related knowledge held by major and non-major students was revealed unknown more than the majority of responses. Based on these results, greater effort should be made to provide meaningful information to improve the food-safety knowledge of college students according to mass-media.