Affects Amino Acid Composition Research Articles

Alterations of amino acid metabolism and intestinal microbiota in Chinese mitten crab (Eriocheir sinensis) fed on formulated diet and iced trash fish

Formulated diet (FD) and iced trash fish (ITF) are common diets during E. sinensis farming. However, whether FD can completely replace ITF during long-term E. sinensis farming is still unclear. Thus this study was conducted to compare the differences in amino acid metabolism and intestinal microbiota of the E. sinensis fed on different diets. The crabs were randomly divided into three groups fed on FD, ITF and mixed diet (MD, FD: ITF = 1:1), respectively. The results showed that there were no significant differences in amino acid composition among FD, MD and ITF groups. The activities of AST and ALT, and the mRNA levels of amino acid metabolism-related genes were significantly up-regulated in FD or/and MD groups compared with ITF group. The diversity of intestinal bacterial community was similar between the FD and ITF groups, but the relative abundance of dominant taxa showed marked differences between the two groups. At the phylum level, the relative abundance of Firmicutes was significantly higher, but the relative abundance of Proteobacteria was significantly lower in the FD group than that in ITF group. Meanwhile, at genus level, the relative abundance of Candidatus_Hepatoplasma in FD was higher than that in ITF group. Data related to functional prediction demonstrated that the significantly differenced pathways between the two groups were observed in metabolism (Pyrimidine metabolism, Glycolysis/Gluconeogenesis and Citrate cycle) and environmental information processing (transporters). The overall results indicated that replacement of ITF by FD did not affect amino acid composition, but altered amino acid metabolism and the relative abundance of intestinal microbiota. Our data provided a valuable reference for FD application replacing ITF during long-term E. sinensis farming.

Baked cod consumption delayed the development of kidney and liver dysfunction and affected plasma amino acid concentrations, but did not affect blood pressure, blood glucose or liver triacylglycerol concentrations in obese fa/fa Zucker rats.

Obesity is associated with changes in amino acid metabolism, and studies show that ingestion of fish proteins influence amino acid composition in plasma and urine, in addition to affecting risk factors for metabolic syndrome. Since the majority of fish proteins consumed by humans are as fish fillet, it is of interest to investigate if cod fillet intake affects amino acid composition and metabolic disorders. We hypothesized that a modified AIN-93G diet containing cod fillet would affect amino acid compositions in plasma and urine in obese rats, and also affect risk factors for metabolic syndrome when compared to rats fed a regular AIN-93G diet with casein as the protein source. Obese Zucker fa/fa rats, a rat model of metabolic syndrome, received diets containing 25% protein from lyophilized baked cod fillet and 75% protein from casein (Baked cod diet), or a Control diet with casein for four weeks. The Baked cod diet affected the amino acid composition in plasma, with e.g., lower glycine, histidine, homoarginine, homocysteine, methionine, proline and tyrosine concentrations, but did not affect amino acid concentrations in urine. The concentrations of markers for kidney and liver dysfunction were lower in the Baked cod group, however blood pressure development, fasting and postprandial glucose, and hepatic triacylglycerol concentrations were similar to the Control group. To conclude, substituting 25% of dietary protein with baked cod fillet affected concentrations of some amino acids in plasma and delayed development of kidney and liver dysfunction, but did not affect blood pressure, glucose concentration or fatty liver.

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.

Comparison of collagen characteristics of sea- and freshwater-rainbow trout skin.

Proximate composition, volatile basic nitrogen content, and concentrations of collagen in skin samples from either sea- (S-RT) or freshwater-rainbow trout (F-RT) were characterized and compared, to assess the effect of the sea or freshwater habitat on these parameters. Results of amino acid composition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, thermal denaturation assay and Fourier transform infrared (FT-IR) spectroscopy of acid-soluble collagens were comparable between the two sample sets. Both acid-soluble collagens from sea- and freshwater-rainbow trout skins contained glycine as the major amino acid and high alanine, proline, and hydroxyproline contents, and was found to be predominantly composed of α1-, α2-, and β-chains. FT-IR spectra of ASCs from S-RT and F-RT skins were quite similar. These findings suggest that different rainbow trout habitats (seawater and freshwater) do not affect amino acid composition and molecular weight properties of ASCs from S-RT and F-RT skins.

Sulfur limitation increases nitrate and amino acid pools in tropical forages

Increasing the supply of sulfur (S) to forage plants can change their nitrogen (N) metabolism, causing changes in the N : S ratio that can potentially affect forage production and quality. The present study was focussed on revealing how supply (low, intermediate, high) of S affects amino acid composition and concentrations of total S, total N, sulfate-S, nitrate-N, and soluble protein in the leaves of tropical pasture species. Greenhouse experiments were conducted in ground quartz (inert solid substrate) culture to examine the effect of S supply in two tropical species: Panicum maximum cv. Tanzania (Guinea grass) and Stylosanthes guianensis cv. Mineirão (stylo). Because legumes have greater S requirement than do grass species, application levels of S varied according to the species. Guinea grass was grown with 0.10, 0.55, 1.00, 1.45, and 1.90 mmol L−1 of S, and stylo with 0.10, 0.70, 1.30, 1.90 and 2.50 mmol L−1 of S. Plants of both species were harvested on two occasions. Low S availability (0.10 mmol L−1) caused a nutritional imbalance with N in Guinea grass and stylo plants, as shown by a high N : S ratio (>60 : 1), and high concentrations of nitrate-N and free amino acids in plant tissues. Increased S supply regulated the N : S ratio at values close to 20 : 1, which provided N and S concentrations more suitable for protein synthesis and optimum forage production for both forage species. Asparagine was the predominant amino acid present in S-limited Guinea grass, whereas arginine was more abundant in S-limited stylo. This result indicates that a limitation of S increases nitrate-N and free amino acids while decreasing plant growth rates and soluble protein concentrations in these forage species.

Generation and Characterization of Three Monoclonal IgM Antiphospholipid Antibodies Recognizing Different Phospholipid Antigens

Antiphospholipid antibodies (APLs) might be involved in the pathogenesis of the antiphospholipid syndrome (APS). This study analyzes the structural characteristics of monoclonal APLs derived from patients with this disease. Patient-derived B cells were immortalized using Epstein-Barr virus transformation and subsequent fusion to the myeloma cell line CB-F7. APL-producing hybridomas were cloned to obtain cell lines producing monoclonal APL. DNA encoding the variable region of heavy and light chains of the antibodies was sequenced and analyzed regarding their usage within the V-gene family and the existence of somatic hypermutation. Binding patterns of APL to various phospholipids and beta-2-glycoprotein-I (beta2-GPI) were determined using ELISA, with special regard to beta2-GPI dependency. As a result, three APL-producing hybridoma cell lines from patients with APS were established: JGG9, HVA2, and HLC9. APLs were of the IgM isotype and showed different binding patterns toward phospholipids and beta2-GPI. One of them, JGG9, showed extensive somatic hypermutations in both the CDR3 region and a framework region of the heavy chain. JGG9 bound to cardiolipin in the presence of the protein cofactor beta2-GPI. In contrast, the antibodies HVA2 and HLC9 (which also showed somatic hypermutations in the CDR3 region) presented polyreactivity to several phospholipids-cardiolipin, phosphatidyl-serine, -ethanolamine, -inositol, -choline, and sphingomyelin-but not to beta2-GPI. In conclusion, JGG9 presents a high degree of mutation in the CDR3 and framework region resulting from the deletions of nucleotides, and affects amino acid composition. Polyreactivity and the absence of cofactor dependency present HLC9- and HVA2-like natural antibodies that have no contact with any antigen. Nonetheless, these natural antibodies show somatic hypermutation of the heavy chain, indicating antigen-driven maturation. Regarding the possible role of APL in infection, HVA2 in particular may represent a pathogen-maturated antibody showing cross-reactivity between phospholipids and infectious agents. Further experiments are needed to reveal the functional activity of these antibodies.

A comprehensive analysis of mammalian mitochondrial genome base composition and improved phylogenetic methods.

Phylogenetic analysis of mammalian species using mitochondrial protein genes has proved to be problematic in many previous studies. The high mutation rate of mitochondrial DNA and unusual base composition of several species has prompted us to conduct a detailed study of the composition of 69 mammalian mitochondrial genomes. Most major changes in base composition between lineages can be attributed to shifts between the proportions of C and T on the L-strand. These changes are significant at all codon positions and are shown to affect amino acid composition. Correlated changes in the base composition of the RNA loops and stems are also observed. Following up from previous studies, we investigate changes in the base composition of all 12 H-strand proteins and find that variability in proportions of C and T is correlated with location on the genome. Variation in base composition across genes and species is known to adversely affect the performance of phylogenetic inference methods. We have, therefore, developed a customized three-state general time-reversible DNA substitution model, implemented in the PHASE phylogenetic inference package, which lumps C and T into a composite pyrimidine state. We compare the phylogenetic tree obtained using the new three-state model with that obtained using a standard four-state model. Results using the three-state model are more congruent with recent studies using large sets of nuclear genes and help resolve some of the apparent conflicts between studies using nuclear and mitochondrial proteins.

Identification of thermophilic species by the amino acid compositions deduced from their genomes.

The global amino acid compositions as deduced from the complete genomic sequences of six thermophilic archaea, two thermophilic bacteria, 17 mesophilic bacteria and two eukaryotic species were analysed by hierarchical clustering and principal components analysis. Both methods showed an influence of several factors on amino acid composition. Although GC content has a dominant effect, thermophilic species can be identified by their global amino acid compositions alone. This study presents a careful statistical analysis of factors that affect amino acid composition and also yielded specific features of the average amino acid composition of thermophilic species. Moreover, we introduce the first example of a 'compositional tree' of species that takes into account not only homologous proteins, but also proteins unique to particular species. We expect this simple yet novel approach to be a useful additional tool for the study of phylogeny at the genome level.

Nitrogen Fertilizer Affects Amino Acid Composition and Quality of Spring Barley Grain

High N rates used to raise yields and the grain protein concentration (GPC) of cereal crops may lower the nutritional value of the grain by reducing the proportion of essential amino acids in the grain protein. Since spring barley (Hordeum vulgare L.) is an important feed grain for monogastric animals in eastern Canada, a 2‐yr field experiment was conducted to determine N fertilization effects on the amino acid composition of the grain protein. Two cultivars, Leger (adapted feed type) and Argyle (unadapted malting type) were grown with four fertilizer treatments. The four fertilizer treatments were 0 or 100 kg N ha−1 applied as ammonium nitrate at seeding, or with 100 kg N ha−1 at seeding plus 50 kg N ha−1 applied at awn emergence as broadcast ammonium nitrate (not included in 1988) or foliar‐applied urea. Amino acid analyses were conducted by ion exchange chromatography. Nitrogen treatments increased protein per grain in both years, but increased GPC in 1988 only. In 1987, N treatments decreased the proportion of lysine in the grain protein but did not affect other amino acids. In 1988, increased N rates reduced the proportion of aspartic acid, threonine, glycine, lysine, and arginine but increased the proportion of glutamic acid and proline in grain protein. Higher N rates reduced the proportion of cyst(e)ine in grain protein in Leger only. Cultivar differences in amino acid composition were inconsistent between years. Higher rates of N fertilizer increased protein per grain and GPC but lowered the nutritional value of barley grain.

Identification and characterization of a new base substitution in the vaccine strain of sabin 3 poliovirus

The complete RNA sequence of Sabin 3 (LED3) used in vaccine in the United States has been determined. The LED3 Sabin 3 sequence contains the attenuating mutations at bases 472 and 2034 but differs from that published by Stanway et al. ( Nucleic Acids Res., 11, 5629–5643, 1983) at two other base positions, 2493 and 6061. The change at base 6061 is silent and does not affect amino acid composition. The other base, a C at position 2493, is contained in the viral capsid protein VP1 and predicts a new Sabin 3 specific amino acid change of an isoleucine instead of a threonine at amino acid 6 of the protein. Reversion of this base to that present in the pathogenic progenitor strain, Leon, is observed to occur after replication of vaccine virus in the gut of primary vaccines and in nervous tissue of neurovirulence test monkeys. Passage conditions have been identified that lead to the reversion of base 2493 as well as the reversion of the attenuated base to the parental base (Leon) at position 472 in the 5′ noncoding region. The observation that these two bases Δposition are found to revert during passage suggests that there is a selective advantage for virus containing the parental bases at these positions.

Free Amino Acids in Grand Fir Needles and the Effects of Different Forms of Foliar-applied Nitrogen

Needles of grand fir, Abiesgrandis (Dougl.) Lindl., were analyzed to determine: (1) how various forms of nitrogen fertilizer affect amino acid composition, and (2) whether amino acids in the needles differ from those in stem bark (determined in a previous study). Young grand fir were grown in a shadehouse and free amino acids were analyzed four times from May to August, using thin-layer electrophoresis and chromatography. The effects of foliar-applied nitrogen fertilizer on needle amino acids depended on the form of nitrogen. Urea or ammonium nitrate promoted large increases in arginine, glutamine, alanine, lysine, and γ-amino butyric acid, whereas calcium nitrate caused smaller increases. The occurrence of several trace amino acids also varied with the form of nitrogen. Comparison of needle amino acids with those in the stem of unfertilized trees revealed that levels of total amino nitrogen, arginine, glutamic acid, and glutamine were much greater in the stem bark than in the needles, but levels of γ-amino butyric acid and alanine were higher in needles. Traces of aspartic acid, ornithine, and tyrosine were found in the needles, but not in the stem.