Amounts Of Branched-chain Amino Acids Research Articles

Elderly-targeted a branched-chain amino acid-enriched snack incorporated with fermented wheat bran: Assessment on physicochemical and sensory characteristics

There is a lack of specialized food addressing the specific dietary needs of the elderly. To this end, extruded snacks containing fermented wheat bran were developed, and their nutritional, physicochemical, and sensory properties were investigated. Different levels (0, 25, 50, 100, and 150 g/kg) of L. acidophilus-inoculated fermented wheat bran were added to brown rice snack formulations. Their physicochemical properties, amino acid composition, total phenolic content (TPC), antioxidant property, and sensory profile were investigated. At the highest fermented wheat bran incorporation (150 g/kg), the snacks exhibited higher protein and dietary fiber (86.6 and 112.8 g/kg, respectively) than other samples. The highest amounts of branched-chain amino acids, isoleucine (5.3 mg/kg), leucine (6.7 mg/kg), and valine (13.8 mg/kg) were seen in snacks with 150 g/kg fermented wheat bran. Upon sensory analysis by serving snacks with or without soaking in milk, the preference scores of milk-soaked snacks were significantly higher than those of snacks alone. Snacks containing 25 g/kg fermented wheat bran garnered overall high acceptability. Incorporating fermented wheat bran into snacks could improve their nutritional, textural, and sensory characteristics.

Effects of different doses of branched-chain amino acid supplementation on recovery following acute eccentric exercise

This study investigated the effect of different amounts of Branched-Chain Amino Acids (BCAA) supplementation on recovery from eccentric exercise. Nine healthy male subjects undertook 4 trials in a randomized crossover design. Participants ingested either a three different amount (2g, 10g, and 20g) of BCAA supplement or placebo before the eccentric exercise. Muscle pain, hunger, vertical jump, balance, and sprint performance were measured before exercise, immediately after exercise, 1, 24, and 48 h. after exercise. All the variables were checked regarding their normal distribution using the Shapiro-Wilk test and data were presented as means ±SD. A repeated-measure, two factor ANOVA was used to examine differences between the four trials over time for balance, speed, vertical jump, hunger, and muscle pain change. No differences were found at baseline values for balance, velocity, vertical jump, hunger, and muscle pain for four trials (p > 0.05). While the main effect of time was statistically significant for balance, speed, vertical jump, hunger, and muscle pain (p

Reduced branched-chain aminotransferase activity alleviates metabolic vulnerability caused by dim light exposure at night in Drosophila

The rhythmic pattern of biological processes controlled by light over 24 h is termed the circadian rhythm. Disturbance of circadian rhythm due to exposure to light at night (LAN) disrupts the sleep-wake cycle and can promote cardiovascular disease, diabetes, cancer, and metabolic disorders in humans. We studied how dim LAN affects the circadian rhythm and metabolism using male Drosophila. Wild-type flies exposed to the dim light of 10 lux at night displayed altered 24 h sleep-wake behavior and expression patterns of circadian rhythm genes. In addition, the flies became more vulnerable to metabolic stress, such as starvation. Whole-body metabolite analysis revealed decreased amounts of branched-chain amino acids (BCAAs), such as isoleucine and valine. The dim light exposure also increased the expression of branched-chain amino acid aminotransferase (BCAT) and branched-chain α-keto acid dehydrogenase (BCKDC) enzyme complexes that regulate the metabolism of BCAAs. Flies with the Bcat heterozygous mutation were not vulnerable to starvation stress, even when exposed to dim LAN, and hemolymph BCAA levels did not decrease in these flies. Furthermore, the vulnerability to starvation stress was also suppressed when the Bcat expression level was reduced in the whole body, neurons, or fat body during adulthood using conditional GAL4 and RNA interference. Finally, the metabolic vulnerability was reversed when BCAAs were fed to wild-type flies exposed to LAN. Thus, short-term dim light exposure at night affects the expression of circadian genes and BCAA metabolism in Drosophila, implying a novel function of BCAAs in suppressing metabolic stress caused by disrupted circadian rhythm.

The Effects of Catabolism Relationships of Leucine and Isoleucine with BAT2 Gene of Saccharomyces cerevisiae on High Alcohols and Esters.

This study sought to provide a theoretical basis for effectively controlling the content of higher alcohols and esters in fermented foods. In this work, isoleucine (Ile) or leucine (Leu) at high levels was used as the sole nitrogen source for a BAT2 mutant and its parental Saccharomyces. cerevisiae 38 to investigate the effects of the addition of amounts of Ile or Leu and BAT2 on the aroma components in the flavor profile using gas chromatography mass spectrometer (GC-MS). The results showed that 2-methyl-butyraldehyde, 2-methyl-1-butanol, and 2-methylbutyl-acetate were the products positively correlated with the Ile addition amount. In addition, 3-methyl-butyraldehyde, 3-methyl-1-butanol, and 3-methylbutyl-acetate were the products positively correlated with Leu addition amount. BAT2 deletion resulted in a significant decline in the yields of 2-methyl-butyraldehyde, 3-methyl-butyraldehyde,2-methyl-1-butanol, and 3-methyl-1-butanol, but also an increase in the yields of 2-methylbutyl-acetate and 3-methylbutyl-acetate. We speculated that BAT2 regulated the front and end of this metabolite chain in a feedback manner. Improved metabolic chain analyses, including the simulated energy metabolism of Ile or Leu, indicated that reducing the added amount of branched-chain amino acids, BAT mutation, and eliminating the role of energy cofactors such as NADH/NAD+ were three important ways to control the content of high alcohols and esters in fermented foods.

Complete dominant inheritance of intracellular leucine accumulation traits in polyploid yeasts

The yeast Saccharomyces cerevisiae is widely used for ethanol production. In the production of alcoholic beverages, flavours are affected mainly by yeast metabolism in the fermentation process. To increase the contents of initial scented fruity flavours, such as isoamyl alcohol and isoamyl acetate, leucine accumulation in yeast cells is induced by a decrease of leucine feedback inhibition in the l-leucine synthetic pathway using conventional mutagenesis. Diploid strains are commonly used in sake brewingbecause of better fermentation performance, such as vitality and endurance, compared with those of haploid strains. Heterozygous mutations are mostly detected in target genes of brewing yeasts generated through mutation breeding. Here we describe that an allele of theLEU4 gene, LEU4G516S , dominantly induced leucine accumulation even in triploid and tetraploid yeasts as with in diploid yeasts. Importantly, we demonstrated that there is no difference in the intracellular amount of branched-chain amino acids between LEU4G516S /LEU4 heterozygous diploids and LEU4G516S /LEU4G516S homozygous diploids. The approach to increase isoamyl alcohol and isoamyl acetate by intracellular leucine accumulation can potentially be applied to a variety of yeast strains, including aneuploid and polyploid yeasts.

Probiotic Administration Increases Amino Acid Absorption from Plant Protein: a Placebo-Controlled, Randomized, Double-Blind, Multicenter, Crossover Study

The fate of dietary protein in the gut is determined by microbial and host digestion and utilization. Fermentation of proteins generates bioactive molecules that have wide-ranging health effects on the host. The type of protein can affect amino acid absorption, with animal proteins generally being more efficiently absorbed compared with plant proteins. In contrast to animal proteins, most plant proteins, such as pea protein, are incomplete proteins. Pea protein is low in methionine and contains lower amounts of branched-chain amino acids (BCAAs), which play a crucial role in muscle health. We hypothesized that probiotic supplementation results in favorable changes in the gut microbiota, aiding the absorption of amino acids from plant proteins by the host. Fifteen physically active men (24.2 ± 5.0 years; 85.3 ± 12.9 kg; 178.0 ± 7.6 cm; 16.7 ± 5.8% body fat) co-ingested 20 g of pea protein with either AminoAlta™, a multi-strain probiotic (5 billion CFU L. paracasei LP-DG® (CNCM I-1572) plus 5 billion CFU L. paracasei LPC-S01 (DSM 26760), SOFAR S.p.A., Italy) or a placebo for 2 weeks in a randomized, double-blind, crossover design, separated by a 4-week washout period. Blood samples were taken at baseline and at 30-, 60-, 120-, and 180-min post-ingestion and analyzed for amino acid content. Probiotic administration significantly increased methionine, histidine, valine, leucine, isoleucine, tyrosine, total BCAA, and total EAA maximum concentrations (Cmax) and AUC without significantly changing the time to reach maximum concentrations. Probiotic supplementation can be an important nutritional strategy to improve post-prandial changes in blood amino acids and to overcome compositional shortcomings of plant proteins. ClinicalTrials.gov Identifier: ISRCTN38903788

The impact of persistent milk consumption in the pathogenesis of type 2 diabetes mellitus

Background: Milk and sugar are excessively consumed in a Western diet. There is increasing epidemiological evidence that the intake of unfermented pasteurized cow´s milk is associated with an increased risk of type 2 diabetes mellitus (T2D). It is the intention of this review to provide translational biochemical evidence for milk´s diabetogenic mode of action. Milk proteins provide the highest amounts of branched-chain amino acids (BCAAs) and thus contribute to total BCAA intake, which enhances BCAA plasma levels associated with increased risk of T2D. The consumption of pasteurized milk raises plasma levels of miRNA-29b, which is a diabetogenic miRNA promoting insulin resistance (IR). miRNA29b inhibits the activity of branched-chain-keta acid dehydrogenase, the rate limiting enzyme of BCAA catabolism, which is impaired in patients with IR and T2D. Milk consumption stimulates mTORC1 activity and increases insulin synthesis. -cell mTORC1 is overactivated in T2D patients resulting in impaired autophagy which enhances endoplasmic reticulum (ER) stress associated with a greater risk of early -cell apoptosis, the pathogenic hallmark of T2D. Chronic insulinotropic action of milk-derived BCAAs, IR-promoting mTORC1 overactivity, and miRNA-29b signaling combined with excessive glucose-mediated insulin secretion overburden -cell insulin homeostasis. Epidemiological and translational evidence identifies continued milk intake as a promoter of T2D, the most common metabolic disease of Western civilization. Keywords: Branched-chain amino acids, branched-chain-keto acid dehydrogenase, diabetes mellitus type 2, insulin resistance, milk, miRNA-29b, mechanistic target of rapamycin complex 1.

Enzymatic bioconversion of feather waste with keratinases of Bacillus cereus PCM 2849

Abstract Enzymatic preparation from culture of keratinolytic Bacillus cereus PCM 2849 was applied for hydrolysis of whole chicken feathers, after sulphitolytic pretreatment. This process was optimized using a three-factor Box-Behnken design, where the effect of substrate concentration, sulphite concentration during pretreatment and reaction temperature was evaluated on the release of amino acids. Obtained results revealed the highest impact of reaction temperature, followed by substrate content and sulphite during pretreatment. Optimal process conditions were established, i.e. temperature 44.4°C, feathers 4.7% and treatment with 25.3 mM sulphite. Amino acid composition of the obtained hydrolysate was analyzed. Glutamic acid (9.21 g·kg−1) and proline were dominant, however significant amount of branched-chain amino acids was also observed. The FTIR analysis of residual substrate revealed the cleavage of disulphide bonds in keratin through the presence of thioester residues. The absence of reduced cysteine residues was confirmed, along with minor changes in proportions of keratin substructures.

A modified diet does not ameliorate muscle pathology in a mouse model for Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is caused by a lack of dystrophin protein. Next to direct effects on the muscles, this has also metabolic consequences. The influence of nutrition on disease progression becomes more and more recognized. Protein intake by DMD patients may be insufficient to meet the increased demand of the constantly regenerating muscle fibers. This led to the hypothesis that improving protein uptake by the muscles could have therapeutic effects. The present study examined the effects of a modified diet, which composition might stimulate muscle growth, on disease pathology in the D2-mdx mouse model. D2-mdx males were fed with either a control diet or modified diet, containing high amounts of branched-chain amino acids, vitamin D3 and ursolic acid, for six weeks. Our study indicates that the modified diet could not ameliorate the muscle pathology. No effects on bodyweight or weight of individual muscles were observed. Neither did the diet affect severity of fibrosis or calcification of the muscles.

Mice deficient in the mitochondrial branched-chain aminotransferase (BCATm) respond with delayed tumour growth to a challenge with EL-4 lymphoma

BackgroundThe mitochondrial branched-chain aminotransferase (BCATm) is a recently discovered cancer marker with a poorly defined role in tumour progression.MethodsTo understand how a loss of function of BCATm affects cancer, the global knockout mouse BCATmKO was challenged with EL-4 lymphoma under different diet compositions with varying amounts of branched-chain amino acids (BCAAs). Next, the growth and metabolism of EL-4 cells were studied in the presence of different leucine concentrations in the growth medium.ResultsBCATmKO mice experienced delayed tumour growth when fed standard rodent chow or a normal BCAA diet. Tumour suppression correlated with 37.6- and 18.9-fold increases in plasma and tumour BCAAs, 37.5% and 30.4% decreases in tumour glutamine and alanine, and a 3.5-fold increase in the phosphorylation of tumour AMPK in BCATmKO mice on standard rodent chow. Similar results were obtained with a normal but not with a choice BCAA diet.ConclusionsGlobal deletion of BCATm caused a dramatic build-up of BCAAs, which could not be utilised for energy or amino acid synthesis, ultimately delaying the growth of lymphoma tumours. Furthermore, physiological, but not high, leucine concentrations promoted the growth of EL-4 cells. BCATm and BCAA metabolism were identified as attractive targets for anti-lymphoma therapy.

Parenteral nutrition for preterm infants: Issues and strategy

Due to transient gut immaturity, most very preterm infants receive parenteral nutrition (PN) in the first few weeks of life. Yet providing enough protein and energy to sustain optimal growth in such infants remains a challenge. Extrauterine growth restriction is frequently observed in very preterm infants at the time of discharge from hospital, and has been found to be associated with later impaired neurodevelopment. A few recent randomized trials suggest that intensified PN can improve early growth; whether or not such early PN improves long-term neurological outcome is still unclear. Several other questions regarding what is optimal PN for very preterm infants remain unanswered. Amino acid mixtures designed for infants contain large amounts of branched-chain amino acids and taurine, but there is no consensus on the need for some nonessential amino acids such as glutamine, arginine, and cysteine. Whether excess growth in the first few weeks of life, at a time when very preterm infants receive PN, has an imprinting effect, increasing the risk of metabolic or vascular disease at adulthood continues to be debated. Even though uncertainty remains regarding the long-term effect of early PN, it appears reasonable to propose intensified initial PN. The aim of the current position paper is to review the evidence supporting such a strategy with regards to the early phase of nutrition, which is mainly covered by parenteral nutrition. More randomized trials are, however, needed to further support this type of approach and to demonstrate that this strategy improves short- and long-term outcome.

Natural history of children and adults with maple syrup urine disease in the NBS-MSUD Connect registry

Maple syrup urine disease (MSUD) is a rare autosomal recessive metabolic disorder (OMIM #248600) in which affected individuals cannot metabolize branched-chain amino acids (BCAA) (leucine, isoleucine, and valine) due to pathogenic variations in one of three genes: BCKDHA, BCKDHB, and DBT encoding the E1α, E1β, and E2 subunits of the branched-chain α-ketoacid dehydrogenase (BCKDH) enzyme complex [1]. Consequently, these amino acids and their corresponding α-ketoacids accumulate in the body. In the United States of America (USA), the incidence of MSUD is approximately 1:198,000 [2], although it is considerably higher in some populations such as Old Order Mennonite (1:358) [3] and Ashkenazi Jewish populations (1:26,000) [4]. Without treatment, MSUD can lead to feeding difficulties, lethargy, seizures, urine and cerumen that smell like maple syrup, vomiting, coma, and death [5]. Early diagnosis and treatment can optimize outcomes, although treated individuals have an increased rate of anxiety, depression, attention deficit hyperactivity disorder (ADHD), movement disorders, and small reductions in intelligence and global function [5]. Treatment consists of a protein-restrictive diet that limits the amount of branched-chain amino acids consumed, along with synthetic formula consisting of the other amino acids and various micronutrients [6]. The goal of treatment is to maintain plasma leucine concentrations, with frequent monitoring, between 75 and 200 μmol/L for infants and children age five years and younger, and between 75 and 300 μmol/L for individuals older than five years of age [7]. Even with dietary treatment, metabolic decompensation can occur during times of stress (e.g., infection) and must be treated promptly [5]. Liver transplants may allow for relaxation of the diet, and can help prevent further brain damage but cannot reverse existing damage [8], [9]. Because treatment must be initiated as soon as possible after birth, screening for MSUD was first included in newborn screening (NBS) programs in the USA in 1964 [10]. In 1999, MSUD was included on the American College of Medical Genetics list of recommended diseases for inclusion in tandem mass spectrometry-based NBS panels [11], and is currently screened for in all states in the USA [2]. In order to add to the literature on outcomes of this rare condition, we report the characteristics of a group of respondents with MSUD from NBS-MSUD Connect, the first self-reported patient registry for metabolic NBS disorders. NBS Connect was launched in 2012 with NBS-PKU Connect for phenylketonuria (PKU) as the pilot registry, and NBS-MSUD Connect was added in 2013 [12]. The purpose of this report is to provide a snapshot of respondents with MSUD, including management techniques employed, clinical symptoms, and factors potentially associated with metabolic control of plasma leucine levels.

Metabolic response of Tetragenococcus halophilus under salt stress

In this study, the effect of salt stress on metabolic response of Tetragenecoccus halophilus was investigated, and the metabolic alternations were analyzed using liquid chromatography-mass spectrometry according to the metabolomics approach. A total of 81 intracellular metabolites were identified, and significant differences were observed in the levels of metabolites mainly participating in central carbon metabolism, fatty acid metabolism, and amino acid metabolism. Analysis of the membrane fatty acid distribution showed that higher proportions of unsaturated fatty acid were observed in salt-treated cells. Additionally, salt-stressed cells exhibited higher amounts of compatible solutes including proline, glycine, citrulline, and N-acetyltyrptophan, and lower amounts of branched-chain amino acids. Interestingly, higher amounts of indole, salicylic acid, and coronatine, which are regarded as signaling molecule and suggested to combat osmotic stress, were detected in salt-shocked cells compared with the untreated cells. Taken together, these results suggested that increased unsaturated membrane fatty acids, accumulation of compatible solutes, and up-regulation of signaling molecule may be potential mechanisms employed by T. halophilus during salt stress.

Generation of electricity from whey: An electrochemical process

This study is concentrated on the electricity generation from whey over and done with a fabricated electrochemical cell. Whey (milk serum) is one of the prominent sources of bio-electrolyte because of containing abundant amount of branched-chain amino acids. Moreover, the pH value of fresh whey was found about 3.1-3.3. Two categories of preservation techniques have been revealed by thermal treatment and adding 2% phenol by volume. It was observed that phenol treated whey was free form microbial attack for longer time compared to that of thermal treatment. In agitation assisted bio-electrochemical reactor, voltage and power density were increased with the increase of electrode surface area. Maximum 17.35 volt was obtained from 6.5 liters of whey through an agitation assisted electrochemical reactor. In addition, commercial alloy electrode shows satisfactory results on power generation and reducing internal resistance compares with the experimental pure metal electrode.

Enhanced production of branched-chain amino acids by Gluconacetobacter europaeus with a specific regional deletion in a leucine responsive regulator

Vinegar with increased amounts of branched-chain amino acids (BCAAs; valine, leucine and isoleucine) is favorable for human health as BCAAs decrease diet-induced obesity and hyperglycemia. To construct Gluconacetobacter europaeus which produces BCAAs, leucine responsive regulator (GeLrp) is focused and two Gelrp mutants were constructed. Wild-type KGMA0119 didn't produce significant amount of valine (0.13 mM) and leucine (0 mM) and strain KGMA7110 which lacks complete Gelrp accumulated valine (0.48 mM) and leucine (0.11 mM) but showed impaired growth, and it was fully restored in the presence of essential amino acids. Strain KGMA7203 was then constructed with a nonsense mutation at codon Trp132 in the Gelrp, which leads a specific deletion at an estimated ligand-sensing region in the C-terminal domain. KGMA7203 produced greater quantities of valine (0.80 mM) and leucine (0.26 mM) and showed the same growth characteristics as KGMA0119. mRNA levels of BCAAs biosynthesis genes (ilvI and ilvC) and probable BCAAs efflux pump (leuE) were determined by quantitative reverse-transcription PCR. Expression rates of ilvI and ilvC in the two Gelrp disruptants were greater than those in KGMA0119. leuE was highly expressed in KGMA7110 only, suggesting that the accumulation in KGMA7110 culture was caused by increased expression of the biosynthesis genes and abnormal enhanced export of amino acids resulting in impaired cell growth. In contrast, KGMA7203 would achieve the high level production through enhanced expression of the biosynthesis genes without enhancing that for the efflux pump. KGMA7203 was considered advantageous for production of vinegar with higher amounts of valine and leucine.

Generation of Bio-Electricity From Whey

This study focused on the generation of electricity from whey in a bio-fuel cell (BFC). Whey or Milk Serum is the liquid remaining after milk has been curdled and strained. It is a by-product of the manufacture of cheese or casein in Foods and Sweets Company. It was selected as electrolyte in biofuel cell due to containing higher amount of branched-chain amino acids (BCAA's).The pH value of fresh whey was 3.1-3.8. Three categories of whey were used in the experiments included fresh whey, preserved by thermal treatment and preserved with 2% phenol by volume. It was observed that microorganism growth was zero in the sample with 2% phenol and growth rate was medium in the sample preserved by thermal treatment and that was higher in the fresh sample. In this biofuel cell, voltage was increased with the increase of surface area of electrodes. For a single compartment containing 8 unit cells, resultant voltage and current were 2.86V and 450?A and four compartment 32 unit cells in series, the values were 10.90V and 8.05mA respectively. When anode area was increased to reduce polarization, power generation was initially high but the decreasing rate of power was also elevated. Finally, for commercial electrodes, maximum power and minimum internal resistance were recorded. The maximum Current, Voltage and Power for commercial electrodes in a single compartment containing 10 unit cells were 78mA, 3.88V and 0.30264W respectively. DOI: http://dx.doi.org/10.3329/jce.v28i1.18105 Journal of Chemical Engineering, Vol. 28, No. 1, December 2013: 22-26

Nutritional Composition and Topoisomerase Inhibitor Activity of Ethnomedicinal Marine Mollusk Nerita albicilla

DNA topoisomerases (topo) I and II are molecular targets of several potent anticancer agents. Thus, inhibitors of these enzymes are potential candidates for anticancer development. Traditionally, Nerita albicilla had been used in Kei Island, Southern Maluku, Indonesia to treat liver disease including cancer. The paper reports on the chemical composition of Nerita albicilla and its topo I inhibitor of hexane, ethyl acetate and methanol extracts. Topoisomerase-I inhibitor activity was determined using the method reported by TopoGEN. The proximate analysis described that Nerita albicilla dried powder contained 12.45% ± 0.05% moisture; 9.17% ± 0.03% ash; 62.05% ± 0.10% protein; 5.58% ± 0.08% fat; 6.60% ± 0.02% crude fiber and 4.15% ± 0.24% carbohydrate (by difference). Furthermore, the protein consisted of 11 essential amino acids and six non-essential amino acids. It contained significant amount of branched-chain amino acids (BCAA) valine, leucine, isoleucine (a total of 187.8 mg g -1 protein) and lower content of aromatic amino acids phenylalanine, tyrosine and histidine (a total of 111.26 mg g -1 protein). The protein score was 92.2. The yield of hexane, ethyl acetate and methanol extracts of Nerita albicilla were 2.05% ± 0.05%, 1.56% ± 0.06% and 6.99% ± 0.14%, respectively. All extracts showed topoisomerase-I inhibitor activities. Minimum inhibitory concentration (MIC) of methanol extract was 2.50 µg mL -1 . Chemical screening of the extracts showed that they contained steroidal and alkaloid compounds. The investigation revealed that Nerita albicilla contains active compounds that could be potential for nutraceutical or pharmaceutical development.

Toxicological responses to acute mercury exposure for three species of Manila clam Ruditapes philippinarum by NMR-based metabolomics

The Manila clam ( Ruditapes philippinarum) has been considered a good sentinel species for metal pollution monitoring in estuarine tidal flats. Along the Bohai coast of China, there are dominantly distributed three species of clams (White, Liangdao Red and Zebra in Yantai population) endowed with distinct tolerances to environmental stressors. In this study, adductor muscle samples were collected from both control and acute mercury exposed White, Liangdao Red and Zebra clams, and the extracts were analyzed by NMR-based metabolomics to compare the metabolic profiles and responses to the acute mercury exposure to determine the most sensitive clam species capable of acting as abioindicator for heavy metal pollution monitoring. The major abundant metabolites in the White clam sample were branched-chain amino acids (leucine, isoleucine and valine), lactate, arginine, aspartate, acetylcholine, homarine and ATP/ADP, while the metabolite profile of Zebra clam sample comprised high levels of glutamine, acetoacetate, betaine, taurine and one unidentified metabolite. For the Liangdao Red clam sample, the metabolite profile relatively exhibited high amount of branched-chain amino acids, arginine, glutamate, succinate, acetylcholine, homarine and two unassigned metabolites. After 48 h exposure of 20 μg L −1 Hg 2+, the metabolic profiles showed significant differences between three clam species, which included increased lactate, succinate, taurine, acetylcholine, betaine and homarine and decreased alanine, arginine, glutamine, glutamate, acetoacetate, glycine and ATP/ADP in White clam samples, and elevated succinate, taurine and acetylcholine, and declined glutamine, glycine, and aspartate in Liangdao Red clam samples, while the increased branched-chain amino acids, lactate, succinate, acetylcholine and homarine, and reduced alanine, acetoacetate, glycine and taurine were observed in the Zebra clam samples. Overall, our findings showed that White clams could be a preferable bioindicator for the metal pollution monitoring based on the more sensitive metabolic changes in the adductor muscle compared with other two (Liangdao Red and Zebra) clam species.

Attenuation of the protein wasting associated with bed rest by branched-chain amino acids

Bed rest is generally accepted as being an appropriate ground-based model for human spaceflight. The objectives of this study were to test the hypothesis that increasing the amount of branched-chain amino acids (BCAAs) in the diet could attenuate the protein loss associated with bed rest. Nineteen healthy subjects were randomized into two groups according to diet. During the 6 d of bed rest, the diets were supplemented with either 30 mmol/d each of three non-essential amino acids, glycine, serine, and alanine (control group), or with 30 mmol/d each of the BCAAs, leucine, isoleucine, and valine (BCAA group). Nutrition was supplied as a commercially available defined formula diet at a rate of 1.3 x REE. Nitrogen (N) balance and urinary 3-MeH excretion were determined for the 6 d. In our results, the urine-based estimate of N balance was 22.2 +/- 14.4 (n = 9) mg N.kg-1.d-1 and 60.5 +/- 10.1 mg (n = 8) N.kg-1.d-1 for the control and BCAA-supplemented groups, respectively (P < 0.05). Urinary 3-MeH excretion was unchanged in both groups with bed rest. We conclude that BCAA supplementation attenuates the N loss during short-term bed rest.

Effect of Dietary Supplementation with Branched-Chain Amino Acids on Spontaneous Motor Activity and Muscle Function in β, β′-Iminodipropionitrile-treated Rats:A Model for Motorneuropathy

Kitahara, Y., T. Maki and K. Torii. Effect of dietary supplementation with branched-chain amino acids on spontaneous motor activity and muscle function in β, β′-iminodipropionitrile-treated rats: A model for motorneuropathy. Physiol Behav 62(3) 453–462, 1997.— β, β′-iminodipropionitrile (IDPN)-induced muscle weakness in rats is a model for motorneuropathy diseases. The effects of oral administration of branched-chain amino acids on the progression of muscle weakness and muscle atrophy induced by the administration of IDPN in the drinking water, were investigated in this study. The spontaneous motor activity of the animals, as measured with a running wheel, slowly declined after IDPN administration, reaching a steady and low level at approximately week 15. Progressive muscle weakness and muscle atrophy were observed beginning at approximately 15 weeks after the initiation of administration of IDPN. Administration of branched-chain amino acids (BCAA) as a dietary supplement did not improve the lowered spontaneous motor activity seen in IDPN animals, but it did significantly improve measures of postural weakness and muscle strength [range of F values (2, 24) = 4.1–9.5, p < 0.05]. Plasma creatinine of the IDPN-treated rats was markedly elevated, and BCAA administration also significantly suppressed this elevation [ F(2, 24) = 41.2, p < 0.05]. Moreover, although BCAA in plasma were elevated in the rats administered BCAA [range of F values (2, 21) = 25.7–29.7, p < 0.05], skeletal muscle showed no differences (at the p < 0.05 level) in the amounts of BCAA, whether or not BCAA were administered. These data suggest that the BCAA taken up in the skeletal muscle were utilized in the muscle of motorneuropathic rats and improved muscle function, such as energy metabolism, and that the BCAA treatment is one important therapeutic approach for retarding the progression of muscle weakness seen in certain neuromuscular disorders.