Effect of dietary sulfur amino acids on the taurine content of rat tissues

Summary.  The effect of dietary sulfur amino acids on the taurine content of rat blood and tissues was investigated. Three types of diet were prepared for this study: a low-taurine diet (LTD), normal taurine diet (NTD; LTD + 0.5% Met), and high-taurine diet (HTD; LTD + 0.5% Met + 3% taurine). These diets had no differing effect on the growth of the rats. The concentration of taurine in the blood from the HTD- and NTD-fed rats was respectively 1,200% and 200% more than that from LTD-. In such rat tissues as the liver, the taurine content was significantly affected by dietary sulfur amino acids, resulting in a higher content with HTD and lower content with LTD. However, little or no effect on taurine content was apparent in the heart or eye. The activity for taurine uptake by the small intestine was not affected by dietary sulfur amino acids. The expression level of taurine transporter mRNA was altered only in the kidney under these dietary conditions: a higher expression level with LTD and lower expression level with HTD. Received January 8, 2002 Accepted January 18, 2002 Published online August 20, 2002 Authors' address: Dr. Hideo Satsu, Laboratory of Food Chemistry, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan, Fax: +81-3-5841-8026 E-mail: asatsu@mail.ecc.u-tokyo.ac.jp Abbreviations: HTD, high-taurine diet; NTD, normal taurine diet; LTD, low-taurine diet; TAUT, taurine transporter; CSA, cysteine sulfinate; CDO, cysteine dioxygenase; CSAD, cysteine sulfinate decarboxylase; PBS, phosphate-buffered saline; DIDS, 4,4′-diisothiocyanostilbene-2′,2′-disulfonic acid     

Influences of total sulfur amino acids and photoperiod on growth,carcass traits,blood parameters,meat quality and cecal microbial load of broilers

The current study aimed to discuss the impact of total sulfur amino acids (TSAA) %, photoperiod, and their interaction on growth performance, carcass and blood indices of broiler chicks. A total of 300 unsexed IR broiler chicks one-week old were used in a factorial arrangement (2 × 3), including two photoperiod systems (22 L: 2 D and 16 L: 8 D) and three experimental rations having three grades of Met + Cyst (TSAA) (70%, 85% and 100% of digestible lysine in starter and finisher diets). Results revealed that the higher LBW and BWG were noticed in birds given TSAA at grades of 1.1 or 0.90 % under 22L: 2D photoperiod at five weeks of age and the whole experimental period (1–5 weeks of age), respectively. The highest live body weight (LBW (and body weight gain (BWG) were recorded in birds received 1.1% TSAA under the long photoperiod compared to the control and the other groups. Birds fed 1.3% TSAA consumed more feed than the other groups. The opposite was found in birds fed 1.1% TSAA under the short photoperiod (16L: 8D). The best feed conversion (FCR) was detected by birds fed 1.1% and 0.90% TSAA diets during the whole experimental period. All carcass traits studied were significantly influenced by TSAA levels, except for the relative weights of abdominal fat and spleen. The interaction effect on was significant on all carcass traits except spleen %. In conclusion, the addition of TSAA at level 1.1 and 0.9 % to starter and finisher diets under a long photoperiod regime improved broiler’s performance, carcass traits, and blood parameters studied.     

Voltammetric investigation of the interactions between superoxide ion and some sulfur amino acids

In this paper, we analyze a group of amino acids containing sulfur, either as thiols or as disulfides and sulfides (l-cysteine, l-cystine, S-carboxymethyl-l-cysteine, N-acetyl-l-cysteine, reduced and oxidized l-glutathione) for their interaction with superoxide ion in protic and aprotic media. Superoxide ion was electrochemically generated by reduction of oxygen molecules dissolved in the solutions. concentration changes due to the presence of interacting species and was easily monitored under mild and controlled experimental conditions, in the presence or in the absence of the selected substrate, in protic and aprotic media. The reactions were followed by cyclic (CV) or linear (LSV) voltammetry, depending on the medium and the electrochemical techniques widely used to study the antioxidant capacity of biological and chemical systems. According to the experimental results, it was concluded that substrates having a free thiol group react with ion giving disulfides and can be considered as antioxidants for the superoxide ion in the following decreasing order: N-acetyl-l-cysteine > l-cysteine > reduced glutathione. Compounds having protected sulfur (l-cystine, S-carboxymethyl-l-cysteine, oxidized glutathione) do not react with the superoxide ion and do not form compounds with a superior S oxidation number, such as sulfoxide and sulfone.     

Effects of dietary L-carnitine and coenzyme Q10 supplementation on performance and ascites mortality of broilers

The study was conducted to determine the effects of dietary L-carnitine and coenzyme Q₁₀ (CoQ₁₀) supplementation on growth performance and ascites mortality of broilers. A 3 × 3 factorial arrangement was employed with three levels (0, 75 and 150 mg/kg) of L-carnitine and three levels of CoQ₁₀ (0, 20 and 40 mg/kg) supplementation during the experiment. Five hundred and forty one-day-old Arbor Acre male broiler chicks were randomly allocated into nine groups with six replicates each. All birds were fed with the basal diets from day 1 to 7 and changed to the experimental diets from day 8. During day 15 to 21 all the birds were exposed to low ambient temperature (15 - 18°C) to induce ascites. The results showed that under this condition, growth performance of broilers were not significantly affected by CoQ₁₀ or L-carnitine + CoQ₁₀ supplementation during week 0 - 3 and 0 - 6, but body weight gain (BWG) of broilers was significantly reduced by 150 mg/kg L-carnitine during week 0 - 6. Packed cell volume (PCV) of broilers was significantly decreased by L-carnitine and L-carnitine + CoQ₁₀ supplementation (P < 0.05). Erythrocyte osmotic fragility (EOF), ascites heart index (AHI) and ascites mortality of broilers were significantly decreased by L-carnitine, CoQ₁₀ and L-carnitine + CoQ₁₀ supplementation. Though no significant changes were observed in total antioxidative capability (T-AOC), total superoxide dismutase (T-SOD) was increased by L-carnitine, CoQ₁₀ and L-carnitine + CoQ₁₀ supplementation (P < 0.05). Malonaldehyde (MDA) content was significantly decreased by CoQ₁₀ and L-carnitine + CoQ₁₀ supplementation. The results indicate that dietary L-carnitine and CoQ₁₀ supplementation reduce ascites mortality of broilers; the reason may be partially associated with their antioxidative effects.     

Genetic-code evolution for protein synthesis with non-natural amino acids

The genetic encoding of synthetic or “non-natural” amino acids promises to diversify the functions and structures of proteins. We applied rapid codon-reassignment for creating Escherichia coli strains unable to terminate translation at the UAG “stop” triplet, but efficiently decoding it as various tyrosine and lysine derivatives. This complete change in the UAG meaning enabled protein synthesis with these non-natural molecules at multiple defined sites, in addition to the 20 canonical amino acids. UAG was also redefined in the E. coli BL21 strain, suitable for the large-scale production of recombinant proteins, and its cell extract served the cell-free synthesis of an epigenetic protein, histone H4, fully acetylated at four specific lysine sites.     

Amino acid requirement of growing pigs depending on amino acid efficiency and level of protein deposition 1st communication: lysine

In this study we investigated the influence of harvest date and genotype on the ruminai degradability of the organic matter of ensiled maize grains. Grains of the varieties Avenir, Byzance, CGS 5104 and CGS 5107 from six different harvest dates were available; they are classified as intermediate types between flint and dent com. The six harvest dates, during which time the dry matter content of the ensiled grains rose from 52% to 66%, extended from 1st September to 19th October. Assuming a passage rate of k=0.08, the effective ruminai degradability declined in this period on average from 93% to just under 79%; variety‐specific deviations also increased markedly during this period. The dry matter content (x, DM in %) of the ensiled grains had a profound influence on ruminai degradation: a highly significant curvilinear decline in ruminai degradability (y) was calculated at increasing DM levels (k = 0.08), which can be described by the equation y = ?0.072x² (±0.010)+7.417x(±1.186)?98.71(±34.58)(B=0.96;s_y,x[%]=1.36).

The ruminai degradability of ensiled maize grains is about 5–10% higher than that of fresh maize grains.     

Amino acid requirement of growing pigs depending on amino acid efficiency and level of protein deposition. 2nd communication: threonine

Forty Swiss Large White pigs (barrows with 31.7 kg initial to 103.7 kg final BW) were equally and randomly assigned to one of four treatments (H0, H200, L0, L200) involving a combination of chromium supplementation (0 or 200 μg/kg) and glycemic index (high GI (H) or low GI (L)). Growth performance, energy and protein digestibility, carcass composition, and some plasma traits were investigated.

The data indicated, that the substitution of dietary carbohydrates with fat and crude fibre (low GI) resulted in lower growth performance due to impaired energy digestibility. Moreover, the strong stimulation of insulin secretion due to the high and rapid availability of carbohydrates of the diets HO and H200 caused increased carcass fat deposition. Chromium supplementation also affected plasma insulin and glucagon concentrations. Depending on glycemic index, chromium affected the growth performance. Daily gain was reduced in pigs of the L200 treatment compared to the L0 group. This finding indicated that the energy availability expressed as GI is one of several nutritional factors, which determine the efficacy of dietary chromium. We could not corroborate evidences that dietary chromium modifies the chemical composition of the whole carcass, but depending on GI, chemical composition of the longissimus muscle was affected.     

Synthesis of the sulfur amino acids: cysteine and methionine

This review will assess new features reported for the molecular and biochemical aspects of cysteine and methionine biosynthesis in Arabidopsis thaliana with regards to early published data from other taxa including crop plants and bacteria (Escherichia coli as a model). By contrast to bacteria and fungi, plant cells present a complex organization, in which the sulfur network takes place in multiple sites. Particularly, the impact of sulfur amino-acid biosynthesis compartmentalization will be addressed in respect to localization of sulfur reduction. To this end, the review will focus on regulation of sulfate reduction by synthesis of cysteine through the cysteine synthase complex and the synthesis of methionine and its derivatives. Finally, regulatory aspects of sulfur amino-acid biosynthesis will be explored with regards to interlacing processes such as photosynthesis, carbon and nitrogen assimilation.     

A sulfur amino acid deficiency changes the amino acid composition of body protein in piglets

Experiments carried out to determine the amino acid requirement in growing animals are often based on the premise that the amino acid composition of body protein is constant. However, there are indications that this assumption may not be correct. The objective of this study was to test the effect of feeding piglets a diet deficient or not in total sulfur amino acids (TSAA; Met + Cys) on nitrogen retention and amino acid composition of proteins in different body compartments. Six blocks of three pigs each were used in a combined comparative slaughter and nitrogen balance study. One piglet in each block was slaughtered at 42 days of age, whereas the other piglets received a diet deficient or not in TSAA for 19 days and were slaughtered thereafter. Two diets were formulated to provide either 0.20% Met and 0.45% TSAA (on a standardized ileal digestible basis) or 0.46% Met and 0.70% TSAA. Diets were offered approximately 25% below ad libitum intake. At slaughter, the whole animal was divided into carcass, blood, intestines, liver, and the combined head, tail, feet and other organs (HFTO), which were analyzed for nitrogen and amino acid contents. Samples of the longissimus muscle (LM) were analyzed for myosin heavy chain (MyHC) and actin contents. Nitrogen retention was 20% lower in piglets receiving the TSAA-deficient diet (P < 0.01). In these piglets, the nitrogen content in tissue gain was lower in the empty body, carcass, LM and blood (P < 0.05) or tended to be lower in HFTO (P < 0.10), but was not different in the intestines and liver. The Met content in retained protein was lower in the empty body, LM and blood (P < 0.05), and tended to be lower in the carcass (P < 0.10). The Cys content was lower in LM, but higher in blood of piglets receiving the TSAA-deficient diet (P < 0.05). Skeletal muscle appeared to be affected most by the TSAA deficiency. In LM, the Met content in retained protein was reduced by 12% and total Met retention by more than 60%. The MyHC and actin contents in LM were not affected by the TSAA content of the diet. These results show that a deficient TSAA supply affects the amino acid composition of different body proteins. This questions the use of a constant ideal amino acid profile to express dietary amino acid requirements, but also illustrates the plasticity of the animal to cope with nutritional challenges.     

Position-specific incorporation of biotinylated non-natural amino acids into a protein in a cell-free translation system

Biotinylation is useful for the detection, purification and immobilization of proteins. It is performed by chemical modification, although position-specific and quantitative biotinylation is rarely achieved. We developed a position-specific biotinylation method using biotinylated non-natural amino acids. We showed that biotinylated p-aminophenylalanine derivatives were incorporated into a protein more efficiently than biotinylated lysine derivatives in a cell-free translation system. In addition, the biotinylated p-aminophenylalanines overcame the serious position-dependency observed for biotinylated lysines. The present method will be useful for detection and purification of proteins along with comprehensive exploration of surface-exposed residues and oriented immobilization of proteins.     

Effect of various kinds of dietary protein and supplementation with limiting amino acids on growth,haemolymph components and uric acid excretion in the silkworm, Bombyx mori

Effects of various kinds of dietary protein on growth of the silkworm, Bombyx mori, were determined using semi-synthetic diets. Also, the ingestion, digestion and utilization of dry matter and of nitrogen were measured. Nutritive effects of dietary proteins and supplementation of limiting amino acids on haemolymph protein and amino acids pattern were also investigated. Larval growth was largely dependent on the dietary proteins. When the larvae were reared on a diet containing weakly nutritive proteins such as gluten and zein, haemolymph protein was decreased and uric acid excretion was markedly accelerated. The free amino acid composition of the haemolymph manifested characteristic patterns according to the kinds of dietary protein.The supplementation of gluten and zein with their limiting amino acids resulted in a rise of haemolymph protein and a drop in uric acid excretion. The amino acid patterns in the haemolymph were greatly changed according to supplementation.     

Effects of leucine supplementation on muscle protein synthesis and degradation pathways in broilers at constant dietary concentrations of isoleucine and valine

The present study investigated the hypothesis that dietary concentrations of leucine (Leu) in excess of the breeder´s recommendations activates protein synthesis and decreases protein degradation in muscle of broilers. Day-old male Ross 308 broilers (n = 450) were phase-fed corn-soybean meal-based diets during starter (d 1–10), grower (d 11–22), and finisher (d 23–34) period. The basal diets fed to the control group (L0) met the broilers’ requirements for nutrients and amino acids, and contained Leu, Leu:isoleucine (Ile) and Leu:valine (Val) ratios, close to those recommended by the breeder (Leu:Ile: 100:54, 100:52, 100:51; Leu:Val 100:64, 100:61, 100:58; in starter, grower and finisher diet, resp.). Basal diets were supplemented with Leu to exceed the breeder’s recommendations by 35% (group L35) and 60% (group L60). Growth performance during 34 d, and carcass weights, and breast and thigh muscle weights on d 34 were similar among groups. Hepatic and muscle mRNA levels of genes involved in the somatotropic axis [growth hormone receptor, insulin-like growth factor (IGF)-1, IGF binding protein 2, IGF receptor] on d 34 were not influenced by Leu. In the breast muscle, relative mRNA abundances of genes involved in the mammalian target of rapamycin (mTOR) pathway of protein synthesis (mTOR, ribosomal p70 S6 kinase) and the ubiquitin-proteasome pathway of protein degradation (F-box only protein 32, Forkhead box protein O1, Muscle RING-finger protein-1) on d 34 were largely similar among groups. Likewise, relative phosphorylation and thus activation of mTOR and ribosomal protein S6 involved in the mTOR pathway, and of eukaryotic translation initiation factor 2A (eIF2a) involved in the general control nonderepressible 2 (GCN2)/eIF2a pathway of protein synthesis inhibition, were not influenced. These data indicate that dietary Leu concentrations exceeding the broiler´s requirements up to 60% neither influence protein synthesis nor degradation pathways nor muscle growth in growing broilers.     

Non‐additive stabilization by halogenated amino acids reveals protein plasticity on a sub‐angstrom scale

It has been a long‐standing goal to understand the structure‐stability relationship of proteins, as optimal stability is essential for protein function and highly desirable for protein therapeutics. Halogenation has emerged as a minimally invasive strategy to probe the physical characteristics of proteins in solution, as well as enhance the structural stabilities of proteins for therapeutic applications. Although advances in synthetic chemistry and genetic code expansion have allowed for the rapid synthesis of proteins with diverse chemical sequences, much remains to be learned regarding the impact of these mutations on their structural integrity. In this contribution, we present a systematic study of three well‐folded model protein systems, in which their structural stabilities are assessed in response to various hydrogen‐to‐halogen atom mutations. Halogenation allows for the perturbation of proteins on a sub‐angstrom scale, offering unprecedented precision of protein engineering. The thermodynamic results from these model systems reveal that in certain cases, proteins can display modest steric tolerance to halogenation, yielding non‐additive consequences to protein stability. The observed sub‐angstrom sensitivity of protein stability highlights the delicate arrangement of a folded protein core structure. The stability data of various halogenated proteins presented herein should also provide guidelines for using halogenation as a strategy to improve the stability of protein therapeutics.     

Screening and development of enzymes for determination and transformation of amino acids

ABSTRACT

The high stereo- and substrate specificities of enzymes have been utilized for micro-determination of amino acids. Here, I review the discovery of l-Phe dehydrogenase and its practical use in the diagnosis of phenylketonuria in more than 5,400,000 neonates over two decades in Japan. Screening and uses of other selective enzymes for micro-determination of amino acids have also been discussed. In addition, novel enzymatic assays with the systematic use of known enzymes, including assays based on a pyrophosphate detection system using pyrophosphate dikinase for a variety of l-amino acids with amino-acyl-tRNA synthetase have been reviewed. Finally, I review the substrate specificities of a few amino acid-metabolizing enzymes that have been altered, using protein engineering techniques, mainly for production of useful chemicals, thus enabling the wider use of natural enzymes.     

Lipophilicity of amino acids

Summary The lipophilicity (or hydrophobicity) of amino acids is an important property relevant for protein folding and therefore of great interest in protein engineering. For peptides or peptidomimetics of potential therapeutic interest, lipophilicity is related to absorption and distribution, and thus indirectly relates to their bioactivity. A rationalization of peptide lipophilicity requires basic knowledge of the lipophilicity of the constituting amino acids. In the present contribution we will review methods to measure or calculate the lipophilicities of amino acids, including unusual amino acids, and we will make a comparison between various lipophilicity scales.     

冷藏对米蛾卵液中游离氨基酸变化的影响

赤眼蜂的工厂化繁育常使用米蛾卵作为中间寄主卵,为了满足赤眼蜂生产的需要,需对米蛾卵进行冷藏,但冷藏米蛾卵影响赤眼蜂的生长发育。利用核磁共振技术(NMR)测定了新鲜米蛾卵(U)、新鲜杀胚米蛾卵(CK)、杀胚米蛾卵在4℃条件下冷藏15 d(N15)、30 d(N30)、45 d(N45)和60 d(N60)后,米蛾卵卵液游离氨基酸种类和含量的变化。结果共鉴定到24种游离氨基酸及其衍生物,包括昆虫发育必需的10种氨基酸。U和CK之间的游离氨基酸组分没有显著差异,N15、N30和N45游离氨基酸总量随冷藏时间的延长而显著升高,N60中的氨基酸总量与N45比较没有显著增加。对24种游离氨基酸及其衍生物的含量进行主成分分析,结果表明丙氨酸、谷氨酰胺、鸟氨酸、天冬氨酸、组氨酸、赖氨酸、丝氨酸、焦谷氨酸等8种氨基酸的含量随冷藏时间的增加而有着显著的变化,其中,丙氨酸变化幅度最为明显,随着冷藏时间的增加,含量从0.1624 mmol/L增加到8.6192 mmol/L;组氨酸在N30、N45和N60处理之间显著下降,从0.7553 mmol/L降低到0.2495 mmol/L。因此,冷藏会导致米蛾卵内游离氨基酸含量发生一定变化,这可能是冷藏米蛾卵影响赤眼蜂生长发育的重要原因之一。     

Effects of graded dose dietary supplementation of Piper betle leaf meal and Persicaria odorata leaf meal on growth performance,apparent ileal digestibility,and gut morphology in broilers

Due to antimicrobial resistance and the public health hazard of antibiotic growth promoters, there is a grave need to find potential alternatives for sustainable poultry production. Piper betle (PB) and Persicaria odorata (PO) are herbs, which have been reported for antimicrobial, antioxidant, and anti-inflammatory properties. The present study aimed to estimate the influence of different dose supplementation of Piper betle leaf meal (PBLM) and Persicaria odorata leaf meal (POLM) on growth performance, ileal digestibility and gut morphology of broilers chickens. A total of 210 one day-old broiler chicks were randomly grouped into 7 treatments, and each treatment group has 3 replicates (n = 10) with a total number of 30 chicks. The treatments included T₁ control (basal diet (BD) with no supplementation), T₂ (BD + 2 g/kg PBLM); T₃ (BD + 4 g/kg PBLM), T₄ (BD + 8 g/kg PBLM), T₅ (BD + 2 g/kg POLM), T₆ (BD + 4 g/kg POLM), T₇ (BD + 8 g/kg POLM). Growth performance, gut morphology and ileal digestibility were measured. Except for T₄ (8 g/kg PBLM), graded dose inclusion of PBLM and POLM increased (P < 0.05) the body weight gain (BWG), positively modulated the gut architecture and enhanced nutrient digestibility in both stater and finisher growth phases of broiler chickens. Birds fed on PBLM 4 g/kg (T₃), and POLM 8 g/kg (T₇) had significantly higher (P < 0.05) BWG with superior (P < 0.05) feed efficiency in the overall growth period. Chickens fed on diets T₃ and T₇ had longer (P < 0.05) villi for duodenum as well as for jejunum. Furthermore, the birds fed on supplementations T₃ and T₇ showed improved (P < 0.05) digestibility of ether extract (EE), and dry matter (DM) compared to the control group. However, least (P < 0.05) crude protein (CP) digestibility was recorded for T_4. In conclusion, dietary supplementations of PBLM 4 g/kg and POLM 8 g/kg were positively modulated the intestinal microarchitecture with enhanced nutrient digestibility, resulted in maximum body weight gain, thus improved the growth performance of broiler chickens.