Changes In Amino Acid Composition Research Articles

The changes in amino acids composition of the blood associated with reproductive losses and their correction

The results of examination of women with reproductive losses (RL) in anamnesis, realized within medical-genetic consultation for explanation of the role of changes of heterochromatin (chromosome polymorphism) and the features of folate metabolism in women with RL with the perspective of individualization of preconception support on the base of determination of character of causal relation between these phenomena, were presented in the article.Aim of research: specification of the role of chromosome polymorphism and changes of amino acid composition of blood in women as the possible markers of high risk of RL.Material and methods: two groups of women were examined: I - 154 observations with obstetric anamnesis, complicated with RL and II - 32 practically healthy women with non-complicated reproductive anamnesis, who underwent preconception prophylaxis before planning of pregnancy. The genealogical anamnesis, features of the state of internal organs, genitals were studied. The special studies included cytogenetic analysis, determination of the level of free sulfur-containing amino acids (methionine, cystine, cysteine, taurine) by the method of highly effective liquid chromatography.Results: The frequency of structural changes of chromosomes in women with RL is 36,4 %. The types of slight chromosome anomalies in 3,9 % was the carriage of extremal variants of C-polymorphism; in 18,8 % – polymorphism of adjacent districts of chromosomes 13, 14, 15, 17, 21, 22; in 1,9 % – increased size of сentromere heterochromatin in chromosome; in isolated cases – the increase of linear sizes of heterochromatin districts of 9 chromosome and combination of polymorphism of adjacent districts of 15 chromosomes. In 7,1 % of cases polymorphism of adjacent districts of 21 chromosome was detected. The statistical connection between the carriage of chromosome and gene polymorphism in women with RL in anamnesis was detected. The significant difference between the main and control groups was detected only for methionine among sulfur-containing amino acids. Hyperhomocysteinemia was detected in 71,9 % of women of the main group.Conclusions: Preventive strategy as to reproductive losses must provide the timely diagnostics and correction of disorders of folate cycle that is determinative component of personalized primary prophylaxis of the disorder of reproductive function of family in the modern Ukrainian population

Characterization of TG2 and TG1-TG2 double knock-out mouse epidermis.

Transglutaminases (TGs) are a family of enzymes that catalyse the formation of isopeptide bonds between the γ-carboxamide groups of glutamine residues and the ε-amino groups of lysine residues leading to cross-linking reactions among proteins. Four members, TG1, TG2, TG3, and TG5, of the nine mammalian enzymes are expressed in the skin. TG1, TG3 and TG5 crosslinking properties are fundamental for cornified envelope assembly. In contrast, the role of TG2 in keratinization has never been studied at biochemical level in vivo. In this study, taking advantage of the TG2 knock-out (KO) and TG1 heterozygous mice, we generated and characterized the epidermis of TG1-TG2 double knock-out (DKO) mice. We performed morphological analysis of the epidermis and evaluation of the expression of differentiation markers. In addition, we performed analysis of the amino acid composition from isolated corneocytes. We found a significant change in amino acid composition in TG1KO cornified cell envelopes (CEs) while TG2KO amino acid composition was similar to wild-type CEs. Our results confirm a key role of TG1 in skin differentiation and CE assembly and demonstrate that TG2 is not essential for CE assembly and skin formation.

Protein and starch characteristics of milled rice from different cultivars affected by transplantation date.

The effects of transplantation date on milled rice (physicochemical, amino acids composition and protein profiling) of different cultivars and their starch characteristics (granules size distribution, pasting and thermal) were investigated. Head rice yield increased (2.0-4.1%) and chalky grains (5-10%) decreased with delaying the paddy transplantation of different cultivars by 20days. Delayed transplantation of paddy significantly increased asparagine, glutamine, threonine, cysteine, methionine, tryptophan, lysine and proline content in milled rice. Early transplantation of paddy showed higher accumulation of glutelin and prolamines than that in milled rice from delayed transplantation. The change in amino acid composition of milled rice with delay in transplantation was related to variation in accumulation of glutelin and prolamines. Starch from delayed transplanted paddy showed higher peak viscosity and lower breakdown viscosity than those from early transplanted paddy. These differences were due to higher accumulation of amylose in starch from delayed transplanted paddy than that from early transplanted paddy due to exposure of former to lower night air temperature during starch synthesis.

Key role of cysteine residues and sulfenic acids in thermal- and H2O2-mediated modification of β-lactoglobulin

Oxidation results in protein deterioration in mammals, plants, foodstuffs and pharmaceuticals, via changes in amino acid composition, fragmentation, aggregation, solubility, hydrophobicity, conformation, function and susceptibility to digestion. This study investigated whether and how individual or combined treatment with heat, a commonly encountered factor in industrial processing, and H2O2 alters the structure and composition of the major whey protein β-lactoglobulin. Thermal treatment induced reducible cross-links, with this being enhanced by low H2O2 concentrations, but decreased by high concentrations, where fragmentation was detected. Cross-linking was prevented when the single free Cys121 residue was blocked with iodoacetamide. Low concentrations of H2O2 added before heating depleted thiols, with H2O2 alone, or H2O2 added after heating, having lesser effects. A similar pattern was detected for methionine loss and methionine sulfoxide formation. Tryptophan loss was only detected with high levels of H2O2, and no other amino acid was affected, indicating that sulfur-centered amino acids are critical targets. No protection against aggregation was provided by high concentrations of the radical scavenger 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), consistent with molecular oxidation, rather than radical reactions, being the major process. Sulfenic acid formation was detected by Western blotting and LC–MS/MS peptide mass-mapping of dimedone-treated protein, consistent with these species being significant intermediates in heat-induced cross-linking, especially in the presence of H2O2. Studies using circular dichroism and intrinsic fluorescence indicate that H2O2 increases unfolding during heating. These mechanistic insights provide potential strategies for modulating the extent of modification of proteins exposed to thermal and oxidant treatment.

Modifications of 'Gold Finger' Grape Berry Quality as Affected by the Different Rootstocks.

Berry qualities of the grafted 'Gold Finger' grapevines were determined to evaluate the impacts of the resistant rootstocks on fruit quality. Compared to the own-rooted vines, berry and cluster weights and skin color were altered by the rootstocks to varying extents. The rootstock of 101-14M maintained TSS/TA and the contents of fructose, glucose, and sucrose, and SO4 decreased these parameters. 101-14M and 3309C increased and reduced the resveratrol content, respectively. SO4, 5BB, and 3309C decreased the total free amino acid content, along with the changes in amino acid composition. The amounts of aroma components were widely altered by the rootstocks. Additionally, a digital gene expression tag profiling revealed that the biological processes were largely altered by 3309C and 101-14M, including sugar, amino acid, and aroma metabolisms. In summary, the rootstock of 101-14M generally maintained berry quality, and SO4, 5BB, and 3309C imparted varying influences on different quality parameters.

English

Changes in amino acid composition are frequently observed in plants under various conditions of stress, such as nutrient deficiencies. Hence, amino acids have been proposed as more sensitive indicators of N status than total N concentration. The goal of this study was to evaluate alterations in amino acid composition of young eucalyptus clones as a result of variable N supply. An experiment was carried out in a greenhouse with two Eucalyptus clones (VM-01 and I-144) and six N application rates (0, 0.74, 2.93, 4.39, 5.85, and 8 mmol L -1 of NH4NO3) grown in a nutrient solution in a randomized block design. Amino acid concentrations varied greatly as a function of N supply and depended on the organ (root or leaf) and the genotype evaluated. Roots showed greater number of amino acids than leaves (17 and 14, respectively), probably because of a higher amino acids synthesis or translocation to the roots. For both clones, N deficiency induced a significant decrease in proline, arginine, and methionine concentration in roots and a decrease in tyrosine, alanine, threonine, and methionine in leaves. These decreases were also associated with lower total N concentration and total dry matter of the eucalyptus clones. In conclusion, N supply affects amino acid composition, and the amino acids listed above are likely to be more sensitive indicators of N status than total N in eucalyptus clones.

Sweat facilitated losses of amino acids in Standardbred horses and the application of supplementation strategies to maintain condition during training

Little is known about the amino acid composition of horse sweat, but significant fluid losses can occur during exercise with the potential to facilitate substantial nutrient losses. Sweat and plasma amino acid compositions for Standardbred horses were assessed to determine losses during a standardised training regime. Two cohorts of horses 2013 (n=5) and 2014 (n=6) were assessed to determine baseline levels of plasma and sweat amino acids. An amino acid supplement designed to counter losses in sweat during exercise was provided after morning exercise daily for 5 weeks (2013, n=5; 2014, n=4). After the supplementation period, blood and sweat samples were collected to assess amino acid composition changes. From baseline assessments of sweat in both cohorts, it was found that serine, glutamic acid, histidine and phenylalanine were present at up to 9 times the corresponding plasma concentrations and aspartic acid at 0-2.2 μmol/l in plasma was measured at 154-262 μmol/l in sweat. In contrast, glutamine, asparagine, methionine and cystine were conserved in the plasma by having lower concentrations in the sweat. The predominant plasma amino acids were glycine, glutamine, alanine, valine, serine, lysine and leucine. As the sweat amino acid profile did not simply reflect plasma composition, it was proposed that mechanisms exist to generate high concentrations of certain amino acids in sweat whilst selectively preventing the loss of others. The estimated amino acid load in 16 l of circulating plasma was 3.8-4.3 g and the calculated loss via sweat during high intensity exercise was 1.6-3.0 g. Following supplementation, total plasma amino acid levels from both cohorts increased from initial levels of 2,293 and 2,044 µmol/l to post-supplementation levels of 2,674 and 2,663 µmol/l respectively (P<0.05). It was concluded that the strategy of providing free amino acids immediately after exercise resulted in raising resting plasma amino acid levels.

Low Temperature Adaptation Is Not the Opposite Process of High Temperature Adaptation in Terms of Changes in Amino Acid Composition.

Previous studies focused on psychrophilic adaptation generally have demonstrated that multiple mechanisms work together to increase protein flexibility and activity, as well as to decrease the thermostability of proteins. However, the relationship between high and low temperature adaptations remains unclear. To investigate this issue, we collected the available predicted whole proteome sequences of species with different optimal growth temperatures, and analyzed amino acid variations and substitutional asymmetry in pairs of homologous proteins from related species. We found that changes in amino acid composition associated with low temperature adaptation did not exhibit a coherent opposite trend when compared with changes in amino acid composition associated with high temperature adaptation. This result indicates that during their evolutionary histories the proteome-scale evolutionary patterns associated with prokaryotes exposed to low temperature environments were distinct from the proteome-scale evolutionary patterns associated with prokaryotes exposed to high temperature environments in terms of changes in amino acid composition of the proteins.

Demonstration of Hole Transport and Voltage Equilibration in Self-Assembled π-Conjugated Peptide Nanostructures Using Field-Effect Transistor Architectures.

π-Conjugated peptide materials are attractive for bioelectronics due to their unique photophysical characteristics, biofunctional interfaces, and processability under aqueous conditions. In order to be relevant for electrical applications, these types of materials must be able to support the passage of current and the transmission of applied voltages. Presented herein is an investigation of both the current and voltage transmission activities of one-dimensional π-conjugated peptide nanostructures. Observations of the nanostructures as both semiconducting and gate layers in organic field-effect transistors (OFETs) were made, and the effect of systematic changes in amino acid composition on the semiconducting/conducting functionality of the nanostructures was investigated. These molecular variations directly impacted the hole mobility values observed for the nanomaterial active layers over 3 orders of magnitude (∼0.02 to 5 × 10(-5) cm(2) V(-1) s(-1)) when the nanostructures had quaterthiophene cores and the assembled peptide materials spanned source and drain electrodes. Peptides without the quaterthiophene core were used as controls and did not show field-effect currents, verifying that the transport properties of the nanostructures rely on the semiconducting behavior of the π-electron core and not just ionic rearrangements. We also showed that the nanomaterials could act as gate electrodes and assessed the effect of varying the gate dielectric layer thickness in devices where the conventional organic semiconductor pentacene spanned the source and drain electrodes in a top-contact OFET, showing an optimum performance with 35-40 nm dielectric thickness. This study shows that these peptides that self-assemble in aqueous environments can be used successfully to transmit electronic signals over biologically relevant distances.

PP3 - Role of oxidation and thermal unfolding in structural changes to beta-lactoglobulin

Oxidation is a major cause of protein deterioration in mammals, plants, foodstuffs and pharmaceuticals, with this giving rise to changes in amino acid composition, fragmentation, aggregation, solubility, hydrophobicity, conformation, susceptibility to digestion and function. Whilst it is well established that these processes have negative impacts on product quality and human health, the mechanisms that generate these alterations are incompletely understood. In this project we are examining whether and how unfolding and oxidation induce changes in the structure of beta-lactoglobulin, to determine whether unfolding alters the rate and mechanism by which samples undergo oxidation, and vice versa. Gaining an understanding of how this occurs is critical to the development of methods to stop undesirable changes, particularly in dairy products where heat treatment is widely used, and oxidation is often encountered. Heat treatment has been shown to result in unfolding of beta-lactoglobulin as assessed by circular dichroism measurements. This effect was increased, in a dose-dependent manner, in the presence of added H 2 O 2 . Addition of high doses of H 2 O 2 before heating also resulted in a shift of the intrinsic (Trp-derived) protein fluorescence maximum to higher wavelengths. Thiol quantification, using 5,5’-dithio-(2-nitrobenzoic acid), revealed that H 2 O 2 depletes thiols in a dose-dependent manner. Using SDS-PAGE, it was shown that whilst heating induced reducible cross-links; pretreatment with high levels of H 2 O 2 prevented the formation of these species. With lower concentrations of H 2 O 2 , reducible cross-links were generated during subsequent heating, consistent with a key role for disulphide formation in heat-induced cross-link formation, with H 2 O 2 diminishing aggregate formation. Altogether, these data indicate that both thermal treatment and oxidation can induce modifications to the protein via competing processes, and alter the vulnerability of the protein to aggregation.

Nutrition status as a criterion of donosologic diagnostics of teenagers health.

The primary purpose – to give estimation ofnutrition status indexes of teenagers and define their role in donosologichealth diagnostics. In the work it is proved that in 17,1% of girls anaemia was diagnosed, in 53,9% – latent deficit of iron. Clinically, symptoms of ascorbic acid deficiency were educed in 50,0%, and its maintenance in the blood serum was reducedin 70,0% of inspected. It is shown that anaemias and latent deficit of iron in teenagers are associated with their activity, anxiety and physical capacity; deficit of ascorbic acid − with the changes of amino acid composition of blood and activity; violations of proteometabolism − with general state, anxiety and physical capacity; increase of both lipids and blood glucose − with their activity; violation of cellular immunity − with activity and general state, and humoral immunity − with the mental capacity of teenagers. It is necessary to take into account all these violations in donosologicdiagnostics of health of the rising generation.

Changes of Nitrogen Compounds During Ensiling of High Protein Herbages – A Review

Abstract Losses of crude protein during ensiling of herbages, in contrast to carbohydrates, do not affect the reduction of its content; their form is changed into greater solubility non-protein compounds and also highly degraded forms, which lower the efficiency of the microbial protein synthesis in the rumen. These processes are accompanied by a change of amino acid composition of herbage protein and decrease in intestinal digestibility of protein from feeds as a result of the formation of indigestible complexes with carbohydrates (ADIN). Reduction of protein degradation in silages is achieved by accelerated acidity through addition of acids or dominance of homofermentative bacteria. The positive effects of fermentation inhibitors or sorbents use, as well as the wilting of raw material on the level and rate of protein degradation were demonstrated by many researchers. A greater contribution of protein nitrogen and reduction of deamination in silages can also be obtained by using bacteria inoculants. Increasing the proportion of protein nitrogen is accompanied by the improved efficiency of microbial protein synthesis.

Organic matter degradation in the German Bight/SE North Sea: Implications from stable nitrogen isotopes and amino acids

Rising stable nitrogen isotope ratios (δ15N) in dated sediment records of the German Bight/SE North Sea track river-induced coastal eutrophication over the last 2 centuries. Fully exploiting their potential for reconstructions of pristine conditions and quantitative analysis of historical changes in the nitrogen cycle from these sediment records requires knowledge on processes that alter the isotopic signal in non-living organic matter (OM) of sinking particles and sediments. In this study, we analyze the isotopic composition of particulate nitrogen (PN) in the water column during different seasons, in surface sediments, and in sediment cores to assess diagenetic influences on the isotopic composition of OM. Amino acid (AA) compositions of suspended matter, surface sediments, and dated cores at selected sites of the German Bight serve as indicators for quality and degradation state of PN. The δ15N of PN in suspended matter had seasonal variances caused by two main nitrate sources (oceanic and river) and different stages of nitrate availability during phytoplankton assimilation. Elevated δ15N values (>20‰) in suspended matter near river mouths and the coast coincide with a coastal water mass receiving nitrate with elevated isotope signal (δ15N>10‰) derived from anthropogenic input. Particulate nitrogen at offshore sites fed by oceanic nitrate having a δ15N between 5 and 6‰ had low δ15N values (<2‰), indicative of an incipient phytoplankton bloom. Surface sediments along an offshore–onshore transect also reflect the gradient of low δ15N of nitrate in offshore sites to high values near river mouths, but the range of values is smaller than between the end members listed above and integrates the annual δ15N of detritus. Sediment cores from the coastal sector of the gradient show an increasing δ15N trend (increase of 2.5‰) over the last 150years. This is not related to any change in AA composition and thus reflects eutrophication. The δ15N signals from before AD 1860 represent a good estimation of pre-industrial isotopic compositions with minimal diagenetic overprinting. Rising δ13C in step with rising δ15N in these cores is best explained by increasing productivity caused by eutrophication.

Effect of nicotinamide on amino acids content in bone collagen depending on biological availability of vitamins in diabetic rats.

Connective tissue is highly susceptible to imbalances induced by diabetes. Diabetes-related osteopenia, decreased bone strength etc. may be associated with altered metabolism of various collagens: Although it is assumed that alterations in collagen amino acids (AA) may strongly affect protein properties andphysiological functions, however, very limited evidences are present at the moment regarding AA composition of bone type I collagen and its relevance to abnormal availability of vitamins which are necessary for collagen synthesis in diabetes. We have tested whether nicotinamide (NAm) can influence type Icollagen formation and AA composition as well as vitamins availability in diabetes. After 4 weeks of STZ-induced diabetes (60 mg/ kg) male Wistar rats were injected for 2 weeks with/without NAm (200 mg/kg b. w). Acid extraction of type I collagen from the bones was performed with following stepwise salting out. The content of type I collagen after its acid extraction from the bones was estimated by the amounts of hydroxyproline. Amino acids were assayed by cation exchange chromatography Diabetes-associated changes in AA composition of type I collagen mainly affect those amino acids which are known to be involved in helix formation and cross-linking of the molecules. Diabetes was found to significantly reduce bone collagen contents of o-Pro, Gly, Ala, o-Lys and Pro, whereas Lys, His, Arg, Glu, Thr, Leu, Phe contents were elevated (P < 0.05). NAm treatment was able to partially normalise AA contents. In diabetes, blood serum and hepatic vitamin C and B3 contents were shown to be significantly lowered, whereas a-tocopherol was slightly increased compared with control (P < 0.05). Restoration of circulatory and liver vitamin C and B3 was observed. The data demonstrate the close relationship between the diabetes-associated decrease in type I collagen deposition, altered amino acids metabolism and impaired availability of vitamins, which are necessary for collagen synthesis. Thus, NAm might be a useful agent for treatment of bone failures related to diabetes.

The amino acid composition of tissue protein is affected by the total sulfur amino acid supply in growing pigs

The factorial approach to assess the amino acid (AA) requirements of pigs is based on the assumption that the AA composition of body protein is constant. However, there are indications that this assumption may not be valid because the AA composition of body protein can be affected by the AA supply. The extent to which different tissues are affected by an AA deficiency is unknown. The objective of this study was to investigate the effect of feeding pig diets with a deficient or sufficient total sulfur AA supply (TSAA; Met+Cys) from 6 to 23 weeks of age on tissue composition and meat quality. The deficient diet (TSAA–) provided 24% Met : Lys and 51% TSAA : Lys on a standardized ileal digestible basis, which are 19% and 16% below the recommended requirements, respectively. The sufficient diet (TSAA+) provided 33% Met : Lys and 60% TSAA : Lys. Diets were offered slightly below the ad libitum feed intake capacity of the pigs. Pigs offered diet TSAA– had a lower average daily gain, lower weights of the longissimus dorsi (LM) and rhomboideus muscles (RM), and of selected skin sections (P<0.05). The weight of different sections of the small intestine and the liver was not affected by the diet. The protein content of the LM and RM decreased in pigs offered diet TSAA– (P<0.05), whereas the protein content of other tissues was not affected. The TSAA supply affected the AA composition (g/16 g N) of protein in all tissues, but the Met content was changed only in the liver (P<0.05). Pigs receiving diet TSAA– had a lower Cys content in the RM and in the distal jejunum and ileum (P<0.01). The deficient TSAA supply resulted in a lower carcass weight and higher muscle glycogen stores (P<0.05), but did not affect other meat quality traits. The results of this study indicate that the muscles, jejunum and ileum respond more to a prolonged AA deficiency than the liver. In addition, the observed changes in AA composition of tissue protein question the use of a constant AA profile of retained protein to assess AA requirements.

Characterization of genipin-modified dentin collagen.

Application of biomodification techniques to dentin can improve its biochemical and biomechanical properties. Several collagen cross-linking agents have been reported to strengthen the mechanical properties of dentin. However, the characteristics of collagen that has undergone agent-induced biomodification are not well understood. The objective of this study was to analyze the effects of a natural cross-linking agent, genipin (GE), on dentin discoloration, collagen stability, and changes in amino acid composition and lysyl oxidase mediated natural collagen cross-links. Dentin collagen obtained from extracted bovine teeth was treated with three different concentrations of GE (0.01%, 0.1%, and 0.5%) for several treatment times (0–24 h). Changes in biochemical properties of NaB3H4-reduced collagen were characterized by amino acid and cross-link analyses. The treatment of dentin collagen with GE resulted in a concentration- and time-dependent pigmentation and stability against bacterial collagenase. The lysyl oxidase-mediated trivalent mature cross-link, pyridinoline, showed no difference among all groups while the major divalent immature cross-link, dehydro-dihydroxylysinonorleucine/its ketoamine in collagen treated with 0.5% GE for 24 h, significantly decreased compared to control (P < 0.05). The newly formed GE-induced cross-links most likely involve lysine and hydroxylysine residues of collagen in a concentration-dependent manner. Some of these cross-links appear to be reducible and stabilized with NaB3H4.

Comparison of evolutionary characteristics of orthologous sets from halophiles, thermophiles and mesophiles

Molecular evolution is the change of amino acid composition at locus specific positions of proteins for maintaining structural and functional integrity over long periods of time. In orthologous protein sets, adapted in different environmental conditions such as normal, high temperature and high ionic condition might have different or identical evolutionary characters. To understand the basis of this fact and to assess the differentials, if any are there, I perform detailed computational analysis on clusters of orthologous protein sequences procured from halophiles, thermophiles and mesophiles using authentic web based and our laboratory-developed programs. Results reveal domain of lives and orthologous protein specific variation in these sets. Unlike thermophiles which show higher usage of hetero-pairs with dominant pair from hydrophobic ones, halophiles, show lower usage with dominant hetero-pairs as ED. Maximally diverse residue is from bulky hydrophobic class in thermophiles and that in the halophiles is acidic ones. Overall, the study demonstrates domain of lives and orthologous proteins specific evolutionary characteristics, the information of which has potential application in biological evolution of homologous proteins under different solvent conditions.

Amino Acids as biomarkers in the SOD1G93A mouse model of ALS

The development of therapies for Amyotrophic Lateral Sclerosis (ALS) has been hindered by the lack of biomarkers for both identifying early disease and for monitoring the effectiveness of drugs. The identification of ALS biomarkers in presymptomatic individuals might also provide clues to the earliest biochemical correlates of the disease. Previous attempts to use plasma metabolites as biomarkers have led to contradictory results, presumably because of heterogeneity in both the underlying genetics and the disease stage in the clinical population. To eliminate these two sources of heterogeneity we have characterized plasma amino acids and other metabolites in the SOD1G93A transgenic mouse model for ALS. Presymptomatic SOD1G93A mice have significant differences in concentrations of several plasma metabolites compared to wild type animals, most notably in the concentrations of aspartate, cystine/cysteine, and phosphoethanolamine, and in changes indicative of methylation defects. There are significant changes in amino acid compositions between 50 and 70days of age in both the SOD1G93A and wild type mice, and several of the age-related and disease-related differences in metabolite concentration were also gender-specific. Many of the SOD1G93A-related differences could be altered by treatment of mice with methionine sulfoximine, which extends the lifespan of this mouse, inhibits glutamine synthetase, and modifies brain methylation reactions. These studies show that assaying plasma metabolites can effectively distinguish transgenic mice from wild type, suggesting that one or more plasma metabolites might be useful biomarkers for the disease in humans, especially if genetic and longitudinal analysis is used to reduce population heterogeneity.

Antioxidant activities of Se-SPI produced from soybean as accumulation and biotransformation reactor of natural selenium

A study to compare the uptake, translocation, and distribution of selenium (Se) in soybean planted in natural seleniferous soil in Fengcheng city of China was conducted to clarify the relationship between the Se content levels of soybean proteins and their radical scavenging activity. The data showed that the total Se content in different parts of soybean plants varied with the growth periods. The selenoprotein (Se-SPI) content increased remarkably with the increase of Se content in seleniferous soils. The Se-SPI content obtained from the region with the highest Se level was almost 18 times higher than that of the control group, while antioxidant activities were about 4-fold compared to the control, suggesting that Se played a positive role in enhancing the antioxidant activity of Se-SPI. The increase in the Se level also led to changes in amino acids composition, but with nearly no effects on the subunit composition of soybean Se-SPI.

Uncovering Spider Silk Nanocrystalline Variations That Facilitate Wind-Induced Mechanical Property Changes

Spider major ampullate (MA) silk varies in mechanical properties when spun in different environments. Amino acid compositional changes induced by variations in MaSp1 and MaSp2 expression, and various biochemical and physiological glandular processes induce silk property variability. Quantifying the contributions of these mechanisms on silk variability may facilitate the development of silk biomimetics. Wind is a medium that induces variations in MA silk mechanics. We exposed the spider Cyclosa mulmeinensis to wind and measured the amino acid composition, tensile mechanics, and crystalline structure of its MA silk using HPLC, tensile tests, and X-ray diffraction. We found the mechanical properties of MA silks from spiders exposed to wind to differ from unexposed spiders. The amino acid compositions did not differ, but X-ray diffraction found a lower crystal density and greater β-sheet alignment relative to the fiber axis in the silks of spiders exposed to wind. We found no evidence that the mechanical property variations were a product of profound changes to the alignment of the protein within the amorphous region. We conclude that variations in the density and alignment of the crystalline β-sheets, probably accompanied by some alignment change in the amorphous region as a result of "stretching" during spinning of the silk, probably explains the mechanical property variations that we found across treatment subgroups. As C. mulmeinensis MA silk increases both in strength and elasticity when the spiders are exposed to wind, bioengineers may consider it as a model for the development of high-performance silk biomimetics.