Determination of Carbon and Nitrogen Isotope Fractions in Asparagine, Aspartic Acid, Threonine and Methionine

The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.

Feeding Practices and Use of Lysine and Methionine in Pigrationing on Intensified Pig Breeding in the West Center and Hauts Bassins Regions of Burkina Faso

The aim of the study was to assess feeding practices and the use of lysine and methionine in pig rationing on intensified and semi-intensive pig breeding in the Koudougou and Bobo-Dioulasso areas. To this end, a cross-sectional survey was carried out on 87 breeding in these towns. A Discriminant Factorial Analysis (DFA) confirming a k-means classification of the data collected was used to retain 71 breeding divided into three breeding classes: Class A (32.4% of breeding), Class B (14.08%) and Class C (53.52%). The results show that the majority of pig breeders were men between the ages of 36 and 59. Average herd sizes were 35 ± 28;79 ± 42 and 89 ± 21 pigs for Classes A, B and C respectively. The main breeds of pig found on the breeding were crossbred, Large white, local, Landrace and Duroc. Class A (26.1%), B (30%) and C (15.8%) breeders were familiar with both lysine and methionine. Class A breeders distributed feed staggered (65.2%) and in rations (34.8%). Lysine (13%) and methionine (8.7%) were purchased at 5250 FCFA/kg. Those in class B distributed feed staggered (50%) and in the form of rations (50%), in which they incorporated lysine (30%) and methionine (30%) purchased at a cost of 2500 FCFA/kg and 3000 FCFA/kg respectively. Rationing and staggered feeding were practiced by 23.7% and 76.3% of Class C breeders respectively. Only lysine purchased at 3400 FCFA/kg was incorporated into rations by 10.5% of breeders. The high cost of lysine and methionine was incriminated by Class A (100%), B (33.3%) and C (50%) breeders. In conclusion, intensive pig breeding, the practice of rationing and the incorporation of the amino acids lysine and methionine are of ascending importance from classes C, A to B. The high cost of feedstuffs, particularly lysine and methionine, compromises their use in rations, which could have a negative impact on expected breeding performance. The screening and use of feeds rich in and/or enriched with these amino acids, through the development or adaptation of technologies, could improve the efficiency of rations and the productivity of intensive pig breeding in Burkina Faso.

Facile synthesis of N-6 adenosine modified analogue toward S-adenosyl methionine derived probe for protein arginine methyltransferases

Chemically modified cellular co-factors that provide function,such as immobilization or incorporation of fluorescent dyes,are valuable probes of biological activity.A convenient route to obtain S-adenosyl methionine（AdoMet） analogues modified at N-6 adenosine to feature a linker terminating in azide functionality is described herein.Subsequent decoration of such AdoMet analogues with guanidinium terminated linkers leads to novel potential bisubstrate inhibitors for protein arginine methyltrans-ferases, PRMTs.

Effects of methionine treatment on storage quality and antioxidant activity of postharvest jujube fruit

Jujube fruits usually suffer from physiological disorders or infectious diseases during storage,leading to quality deterioration,softening,or rotting.Therefore,this study aims to investigate the effect of methionine soaking treatment on the postharvest jujube fruit decay rate and storage quality.Methionine treatment significantly reduced the decay rate of postharvest jujube fruit and effectively maintained fruit color and titratable acid.Methionine treatment effectively delayed the decrease of firmness,soluble solids,ascorbic acid,and lignin contents in jujube fruit.Methionine treatment reduced the content of alanine and phenylalanine,and increased the content of glycine in jujube fruit,but displayed no significant effect on total amino acid content.In addition,jujube fruits in the methionine treatment group had a higher total phenolic and flavonoid content and antioxidant capacity,both in free and bound forms.Compared with the control,methionine treatment also significantly increased the content of individual phenolic acid fractions(gallic acid,vanillic acid,and syringic acid)and flavonoid fractions(catechin,epicatechin,rutin)in free form as well as individual phenolic acid fractions in bound form(gallic acid and ferulic acid)in jujube fruits.Overall,this study suggested that the methionine treatment could be used as a prospective preservative to reduce the postharvest decay of jujube fruit and alleviate its nutritional quality deterioration during cold storage at 4°C.

Lipid metabolism and m^(6)A RNA methylation are altered in lambs supplemented rumen-protected methionine and lysine in a low-protein diet

Background:Methionine or lysine has been reported to influence DNA methylation and fat metabolism,but their combined effects in N6-methyl-adenosine(m^(6)A)RNA methylation remain unclarified.The combined effects of rumen-protected methionine and lysine(RML)in a low-protein(LP)diet on lipid metabolism,m^(6)A RNA methylation,and fatty acid(FA)profiles in the liver and muscle of lambs were investigated.Sixty-three male lambs were divided into three treatment groups,three pens per group and seven lambs per pen.The lambs were fed a 14.5%crude protein(CP)diet(adequate protein[NP]),12.5%CP diet(LP),and a LP diet plus RML(LP+RML)for 60 d.Results:The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin(P=0.07),triglyceride(P=0.05),and non-esterified FA(P=0.08).Feeding a LP diet increased the enzyme activity or m RNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet.This effect was reversed by supplementation of RML with a LP diet.The inclusion of RML in a LP diet affected the polyunsaturated fatty acids(PUFA),n-3 PUFA,and n-6 PUFA in the liver but not in the muscle,which might be linked with altered expression of FA desaturase-1(FADS1)and acetyl-Co A carboxylase(ACC).A LP diet supplemented with RML increased(P<0.05)total m^(6)A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein(FTO)and alk B homologue 5(ALKBH5).The m RNA expressions of methyltransferase-like 3(METTL3)and methyltransferase-like 14(METTL14)in the LP+RML diet group were lower than those in the other two groups.Supplementation of RML with a LP diet affected only liver YTH domain family(YTHDF2)proteins(P<0.05)and muscle YTHDF3(P=0.09),which can be explained by limited m^(6)Abinding proteins that were mediated in m RNA fate.Conclusions:Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle.These changes in fat metabolism may be associated with the modification of m^(6)A RNA methylation.

Hepatoprotective effects of S-adenosyl-L-methionine against alcohol-and cytochrome P450 2E1-induced liver injury

S-adenosyl-L-methionine (SAM) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione. SAM is also a key metabolite that regulates hepatocyte growth, differentiation and death. Hepatic SAM levels are decreased in animal models of alcohol liver injury and in patients with alcohol liver disease or viral cirrhosis. This review describes the protection by SAM against alcohol and cytochrome P450 2E1-dependent cytotoxicity both in vitro and in vivo and evaluates mechanisms for this protection.

S-Adenosyl-L-methionine towards hepatitis C virus expression: Need to consider S-Adenosyl-L-methionine's chemistry, physiology and pharmacokinetics

S-Adenosyl-L-methionine(SAM) is a cofactor serving as a methyl donor in numerous enzymatic reactions. It has been reported that SAM has the potential to modify antioxidant-enzymes, glutathione-biosynthesis and methionine adenosyltransferases-1/2 in hepatitis C virus-expressing cells at millimolar concentrations. The efficacy of SAM at micromolar concentrations and the underlying mechanisms remain to be demonstrated.

S-adenosyl-methionine decreases ethanol-induced apoptosis in primary hepatocyte cultures by a c-Jun N-terminal kinase activity-independent mechanism

AIM:To determine the role of c-Jun N-terminal kinase(JNK)activity in ethanol-induced apoptosis and themodulation of this signaling cascade by S-Adenosyl-methionine(AdoMet).METHODS:Primary hepatocyte cultures werepretreated with 100 μmol/L SP600125,a selective JNKinhibitor,1 mL/L DMSO or 4 mmol/L AdoMet and thenexposed to 100 mmo/L ethanol.Hepatocyte apoptosiswas determined by the TUNEL and DNA ladder assays.JNK activity and its inhibition by SP600125 and AdoMetwere determined by Western blot analysis of c-junphosphorylation and Bid fragmentation.SP600125 andAdoMet effects on the apoptotic signaling pathway weredetermined by Western blot analysis of cytochrome crelease and pro-caspase 3 fragmentation.The AdoMeteffect on glutathione levels was measured by Ellman'smethod and reactive oxygen species(ROS)generationby cell cytometry.RESULTS:The exposure of hepatocytes to ethanolinduced JNK activation,c-jun phosphorylation,Bidfragmentation,cytochrome c release and pro-caspase 3cleavage;these effects were diminished by SP600125,and caused a significant decrease in ethanol-inducedapoptosis(P<0.05).AdoMet exerted an antioxidanteffect maintaining glutathione levels and decreasing ROSgeneration,without a significant effect on JNK activity,and prevented cytochrome c release and pro-caspase 3cleavage. CONCLUSION:The JNK signaling cascade is a keycomponent of the proapoptotic signaling pathwayinduced by ethanol.JNK activation may be independentfrom ROS generation,since AdoMet which exertedantioxidant properties did not have a significant effect onJNK activity.JNK pathway modulator agents and AdoMetmay be components of promising therapies for alcoholicliver disease(ALD)treatment.

A study of preoperative methionine-depleting parenteral nutrition plus chemotherapy in gastric cancer patients

AIM To investigate the interference ofmethionine.free parenteral nutrition plus 5-Fu（-MetTPN+5-Fu）in gastric cancer cell kineticsand the side effects of the regimen.METHODS Fifteen patients with advancedgastric cancer were randomly divided into twogroups,7 patients were given preoperatively aseven-day course of standard parenteralnutrition in combination with a five-day courseof chemotherapy（sTPN+5-Fu）,while the other8 patients were given methionine-deprivedparenteral nutrition and 5-Fu（-MetTPN+5-Fu）.Cell cycles of gastric cancer and normal mucosawere studied by flow cytometry（FCM）.Bloodsamples were taken to measure the serumprotein,methionine（Met）and cysteine（Cys）levels,and liver and kidney functions.RESULTS As compared with the resultsobtained before the treatment,the percentage ofG0/G1 tumor cells increased and that of S phasedecreased in the-MetTPN+5-Fu group,while thecontrary was observed in the sTPN+5-Fu group.Except that the ALT,AST and AKP levels wereslightly increased in a few cases receiving-MetTPN+5-Fu,all the other biochemicalparameters were within normal limits.Serum Cys level decreased slightly after the treatmentin both groups.Serum Met level of patientsreceiving sTPN+5-Fu was somewhat higher aftertreatment than that before treatment;however,no significant change occurred in the -MetTPN+5-Fu group,nor operative complications in bothgroups.CONCLUSION -MetTPN+5-Fu exerted asuppressive effect on cancer cell proliferation,probably through a double mechanism ofcreating a state of'Met starvation'adverse tothe tumor cell cycle,and by allowing 5-Fu to killspecifically cells in S phase.Preoperative short-term administration of -MetTPN+5-Fu had littleundesirable effect on host metabolism.

Methionine adenosyltransferases in liver cancer

Methionine adenosyltransferases(MATs)are essential enzymes for life as they produce S-adenosylmethionine(SAMe),the biological methyl donor required for a plethora of reactions within the cell.Mammalian systems express two genes,MAT1A and MAT2A,which encode for MATα1 and MATα2,the catalytic subunits of the MAT isoenzymes,respectively.A third gene MAT2B,encodes a regulatory subunit known as MATβwhich controls the activity of MATα2.MAT1A,which is mainly expressed in hepatocytes,maintains the differentiated state of these cells,whilst MAT2A and MAT2B are expressed in extrahepatic tissues as well as non-parenchymal cells of the liver(e.g.,hepatic stellate and Kupffer cells).The biosynthesis of SAMe is impaired in patients with chronic liver disease and liver cancer due to decreased expression and inactivation of MATα1.A switch from MAT1A to MAT2A/MAT2B occurs in multiple liver diseases and during liver growth and dedifferentiation,but this change in the expression pattern of MATs results in reduced hepatic SAMe level.Decades of study have utilized the Mat1a-knockout(KO)mouse that spontaneously develops non-alcoholic steatohepatitis(NASH)and hepatocellular carcinoma(HCC)to elucidate a variety of mechanisms by which MAT proteins dysregulation contributes to liver carcinogenesis.An increasing volume of work indicates that MATs have SAMe-independent functions,distinct interactomes and multiple subcellular localizations.Here we aim to provide an overview of MAT biology including genes,isoenzymes and their regulation to provide the context for understanding consequences of their dysregulation.We will highlight recent breakthroughs in the field and underscore the importance of MAT’s in liver tumorigenesis as well as their potential as targets for cancer therapy.

Effect of Methionine Deficiency on the Thymus and the Subsets and Proliferation of Peripheral Blood T-Cell,and Serum IL-2 Contents in Broilers

The purpose of this study was to investigate the effects of methionine deficiency on cellular immune function by determining morphological and ultrastructural changes of thymus, thymic cell cycle and apoptosis, peripheral blood T-cell subsets, T- cell proliferation function and the serum interleukin-2 （IL-2） contents. 120 1-d-old broilers were randomly divided into two groups （6 replicates in each group and l0 broilers in each replicate） and fed on a control diet or methionine deficient diet for 42 d. Lesions were observed in experiment. Histopathologically, lymphopenia and congestion were observed in the medulla of thymic lobule. Ultrastructurally, there were more apoptosis lymphocytes, and the mitochondria of lymphocytes were swelled in thymus of methionine deficiency. The G0/G~ phase of the cell cycle of the thymus was much higher （P〈0.01）, and the S, G2＋M phases and proliferating index （PI） were lower （P〈0.01） in methionine deficiency than in control group. And the percentage of apoptotic cells in the thymus was significantly increased in methionine deficiency （P〈0.01）. The percentage of CD4＋ and CD8~ T-cells was decreased in methionine deficiency compared with control group. Meanwhile, the proliferation function of peripheral blood T-cell was decreased in methionine deficiency. Also, the serum IL-2 contents were decreased in methionine deficiency. It was concluded that methionine deficiency could cause pathological and ultrastructural changes of thymus, reduce the T-cell population, serum IL-2 contents and the proliferation function of T- cells, and induce increased percentage of apoptotic cells. The cellular immune function was finally impaired in broilers.

Polymorphism of Methionine Synthase Gene in Nuclear Families of Congenital Heart Disease

Objective To investigate the relation of methionine synthase (MS) gene variation with congenital heart disease (CHD) phenotype. Methods One hundred and ninety three CHD patients (94 males and 99 females) and their biological parents (nuclear families) in Liaoning Province were selected as the case group, and another 104 normal persons (60 males and 44 females) and their parents without family history of birth defects as the control group. For all subjects the polymorphism of MS gene A2756G locus was examined by PCR-RFLP method. Results In offspring of the control group the frequencies of MS genotype (+/ -) and allele (+) were 10.7% and 5.3%, without existence of homozygote. The MS genotype distribution and allele frequencies of CHD patients and their mothers were not significantly different from the control (P > 0.05). The frequency of allele (+) in case fathers (5.0 %) was apparently lower than that in the control (9.1%, P=0.060), and the odds ratio (OR) was 0.53 (95% CI: 0.25-1.09). There was no difference in parents' genotype combination between the two groups, and in genotype distribution among different types of CHD. Analysis of genetic transmission indicated that mutation allele (+) existed transmission disequilibrium in CHD nuclear families. The percentage of allele (+) transmitted from parents was lower than that allele (-) with OR 0.26 (95% CI: 0.11-0.60). Conclusion MS gene variation in parents is associated with occurrence of CHD in offspring, and mutation allele (+) in parents may be related with the decrease of CHD risk in offspring.

The relationship between dietary methionine and growth,digestion,absorption,and antioxidant status in intestinal and hepatopancreatic tissues of sub-adult grass carp(Ctenopharyngodon idella)

Background: Methionine is an essential amino acid for fish. The present study was conducted to investigate the effects of dietary methionine on growth performance, digestive and absorptive ability, as well as antioxidant capacity in the intestine and hepatopancreas of sub-adult grass carp(Ctenopharyngodon idella).Results: Dietary methionine deficiency significantly decreased percentage weight gain(PWG), feed intake, feed efficiency and protein efficiency ratio, as well as activities of hepatopancreatic glutamate-oxaloacetate transaminase and muscle glutamate-pyruvate transaminase in sub-adult grass carp(P < 0.05). Furthermore, methionine deficiency significantly reduced activities of trypsin, lipase and amylase in the intestine, Na^+/K^+-ATPase, alkaline phosphatase and γ-glutamyl transpeptidase in three intestinal segments, and creatine kinase(CK) in the proximal intestine(P < 0.05). However, an unexplained and significant increase in CK activity in the mid intestine was associated with dietary methionine deficiency. Malondialdehyde and protein carbonyl contents in the intestine and hepatopancreas were significantly increased by methionine deficiency(P < 0.05), whereas anti-hydroxyl radical capacity in the hepatopancreas and intestine, and anti-superoxide anion capacity in the intestine, were significantly decreased by methionine deficiency(P < 0.05). Moreover, methionine deficiency significantly decreased superoxide dismutase and glutathione reductase activities, glutathione contents in the hepatopancreas and intestine, as well as glutathione peroxidase activity in the intestine(P < 0.05), whereas it significantly increased activities of catalase in the hepatopancreas and glutathione-S-transferase in the hepatopancreas and intestine(P < 0.05).(Continued on next page)(Continued from previous page)Conclusions: The present results demonstrated that dietary methionine deficiency induced poor growth, and decreased digestive and absorptive function and antioxidant capacity in the hepatopancreas and intestine of sub-adult grass carp. Methionine requirements for sub-adult grass carp(450-1, 170 g) based on PWG, intestinal trypsin, and hepatopancreatic anti-hydroxyl radical activities were estimated to be 6.12 g/kg diet(21.80 g/kg protein),6.99 g/kg diet(24.90 g/kg protein) and 5.42 g/kg diet(19.31 g/kg protein), respectively, in the presence of 1.50 g cysteine/kg(5.35 g/kg protein).

A high methionine,low folate and vitamin B_6/B_(12) containing diet can be associated with memory loss by epigenetic silencing of netrin-1

Memory-epigenetics which is the loss of memory due to epigenetic modifications can be due to the silencing of genes involved in cognitive functions and this is the basis of the current study.We hypothesize that a diet containing high methionine and low vitamins can lead to memory impairment by increasing global DNA methylation and therefore,silencing the netrin-1 gene,which encodes the glycoprotein involved in neurogenesis,axonal guidance and maintenance of the synaptic plasticity.Wild type(C57 BL/6 J) mice were fed with a diet containing excess methionine(1.2%),low-folate(0.08 mg/kg),vitamin B_6(0.01 mg/kg),and B_(12)(10.4 mg/kg) for 6 weeks.Mice were examined weekly for the long-term memory function,using a passive avoidance test,which determined loss of fear-motivated long-term memory starting from the fourth week of diet.Similarly,an increase in brain %5-methyl cytosine was observed starting from the 4 th week of diet in mice.Mice fed with a high methionine,low folate and vitamins containing diet showed a decrease in netrin-1 protein expression and an increase in netrin-1 gene promotor methylation,as determined by methylation-sensitive restriction enzyme-polymerase chain reaction analysis.The increase in methylation of netrin-1 gene was validated by high-resolution melting and sequencing analysis.Furthermore,the association of netrin-1 with memory was established by administering netrin that considerably restored long-term fear motivated memory.Taken together,these results suggest that a diet rich in methionine and lacking in folate and vitamin B_6/B_(12) can induce defects in learning and memory.Furthermore,the data indicates that decrease in netrin-1 expression due to hyper-methylation of its gene can be associated with memory loss.The animal procedures were approved by the Institutional Animal Care and Use Committee,University of Louisville,USA(No.A3586-01) on February 2,2018.

Study on Lysine and Methionine Content Promotion of Soybean Meal by Probiotic Fermentation Process

Soybean meal （SBM） is commonly used for livestock feeds, but its application in diets for livestock is limited due to some antinutritional factors. The contents of methionine and lysine of soybean meal were promoted by Bacillus natto and Leuconostoc mesenteroides fermentation, benefial for the livestock feeds. It was crude protein （CP） 56.8%, methionine 43.56 mg · g^-1, and lysine 74.87 mg · g^-1, cows fed a diet with FSBM milk yield raised 14.2%, the change in the milk protein, the lactose and the dry matter content had also obvious increase. This convenient technique offers helpful exploration for industrialization of soybean meal fermentation.

Dietary Methionine Affect Meat Qulity and Myostatin Gene Exon 1 Region Methylation in Skeletal Muscle Tissues of Broilers

Dietary amino acids imbalance will result in stunted broiler performance and deteriorated meat quality, which are involved in various biochemical cycles in vivo. In this study, the effects of dietary methionine on meat quality and methylation of myostatin exon 1 were investigated. Drip loss of the broilers fed with diet of high methionine levels （0.2%） increased from （6.3 ± 0.1）% （control group） to （10.1 ± 1.0）%, and the muscle shearing force increased from （22.8 ± 1.9） N （control group） to （26.3 ±2.3） N. Moreover, many CpG sites were found at the myostatin exon 1 region （nucleotides 2 360-2 540 bp）. To further understand the regulation of broiler myostatin expression, the methylation status of broiler myostatin exon 1 and its mRNA expression were analyzed. At the myostatin exon 1 region where CG enriches （nucleotides 2 360-2 540 bp）, the percentages of methylation were 46 and 84% in low Met and high Met content groups after 55-d feeding, respectively. In skeletal muscle tissues, the exon 1 hypermethylation status of myostatin gene was found to be negatively correlated with the gene expression. These results suggested that methylation of this gene is a dynamic process, which plays a dominant role in regulating gene expression for development of individuals.

Lysine, Methionine and Tryptophan Requirements of Beijing Ducklings of 0-2 Weeks of Age

A feed trial was conducted with a total of 1 134 Beijing ducklings to study the optimum level of dietary lysine （Lys） （0.95, 1.10, 1.25%）, methionine （Met） （0.26, 0.46, 0.66%） and tryptophan （Trp） （0.20, 0.30, 0.40%） for those ducklings during a phase of 0-2 weeks. Ducklings were randomly allotted to 27 groups according to a 3 × 3× 3 factorial arrangement and fed a basal corn-soybean-peanut meal diet containing 20.26% CP, 12.45 MJ kg^-1 ME. The results from this study indicate that Lys affected body weight （P〈0.01）, feed intake （0-14 d） （P〈0.01）, but had no effect on feed/gain （0-14 d） （P〉0.05）, uric acid concentration （P 〉 0.05）. Methionine influenced body weight （P 〈 0.01）, feed/gain （P 〈 0.05）, and feed intake （P 〈 0.01）. Tryphtophan had no effect on indices measured. The requirement of the Lys and Met for Beijing ducklings of 0-2 weeks of age were 1.10 and 0.46%. The requirement of Trp for Beijing ducklings of 0-2 weeks of age was not more than 0.20%.

Influence of L-methionine-deprived total parenteral nutrition with 5-fluorouracil on gastric cancer and host metabolism

AIM To investigate the influence of L-methioninedeprived total parentaral nutrition with 5-FU on gastric cancer and host metabolism.``METHODS N-methyI-N-nitro-nitrosoguanidine ( MNNG )induced gastric cancer rats were randomly divided into four groups: Met-containing TPN group (n= 11 ), Metdeprived TPN group (n = 12), Met-containing TPN + 5-FU group (n = 11) and Met-deprived TPN + 5-FU group (n-12). Five rats in each group were sacrificed after 7days of treatment and the samples were taken for examination. The remaining rats in each group were then fed separately with normal diet after the treatment until death, the life span was noted.``RESULTS The tumors were enlarged in Met-containing group and shrank in Met-deprived group markedly after the treatment. The DNA index (DI) of tumor cells and the body weight (BW) of rats had no significant change in the two groups, however, the ratio of tumor cells' S phase was increased The ratio of G2M phase went up in Metcontaining group, but down in Met-deprived group. In the other two groups that 5-FU was added, the BW of rats,and the diameter of tumors, the DI of tumor cells, the S and G2M phase ratio of tumor cells were all decreased,particularly in Met-deprived plus 5-FU group. Pathological examination revealed that the necrotic foci of the tumor tissue increased after Met-deprived TPN treatment, and the nucleoli of tumor cells enlarged. In -MetTPN + 5-FUgroup, severe nuclear damage was also found by karyopyknosis and karyorrhexis, meanwhile there was slight degeneration in some liver and kidney cells. The serum free Met and Cysteine decreased markedly (P<0.001), while other amino acids, such as serum free serine and glutamine increased significantly ( P< 0.005).All the rats died of multiple organ failure caused by cancer metastasis. The average survival time was 18.6 days in Met-containing TPN group. 31 days in Met-deprived TPN group, 27.5 days in Met-containing TPN + 5-FU group, and 43 days in Met-deprived TPN+ 5-FU group (P<0.05).``CONCLUSION Met-deprived TPN causes methionine starvation of tumor cells, and can enhance the anti-tumor effect of 5-FU and prolong the life span of gastric cancerbearing rats.

Effects of Methionine on the Immune Function in Animals

Nutrition and immunity are the hot topics in animal’s production, and the effects of methionine on the immunity are already confirmed as the deep research on the nutrition of amino acid and immune function. However, the relationship of the methionine and immunity has not been elucidated clearly, this review aims to clarify the effects of methionine on immune function in the aspects of growth and development immune organs, the histological structure of the immune organs, non-specific immunity, humoral immunity, cellular immunity and cytokines, and to provide foundations for further studies on the relationship between methionine and immune function.

Biogenic amino acid methionine-based corrosion inhibitors of mild steel in acidic media

N,N-Diallyl methionine ethyl ester hydrochloride 5 underwent alternating copolymerization with SO_2 via the Butler cyclopolymerization protocol in dimethyl sulfoxide(DMSO) to give water-soluble cycloterpolymer 6 with a ～1:1 molar ratio of sulfide and sulfoxide groups as a result of oxygen transfer from DMSO. Half of the sulfide groups in 6, upon oxidation with H_2O_2, afforded polymer sulfoxide 7 and polymer sulfone 8. The solution properties of these polymers were determined via a viscometric technique. The thermal stability of these polymers was determined by thermogravimetric analysis. The inhibition efficiency obtained from gravimetric mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques agreed well with each other. The corrosion efficiencies increase with increasing concentration of the polymers. At a polymer concentration of 175 mM, the maximum inhibition efficiency of copolymer compounds 6–8 was determined to be 92%, 97%, and 95%, respectively. The synthesized polymer compounds acted as mixed-type inhibitors. Polymer compound 7 adsorbed onto the metal surface via chemisorption and physisorption and obeyed Langmuir, Temkin, and Freundlich adsorption isotherms. Analyses by X-ray photoelectron spectroscopy and scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated that the adsorbed polymers formed a thin film on the metal surface and prevented further corrosive attack.