Free Amino Acid Composition Research Articles

Network-Guided GWAS Improves Identification of Genes Affecting Free Amino Acids

Amino acids are essential for proper growth and development in plants. Amino acids serve as building blocks for proteins but also are important for responses to stress and the biosynthesis of numerous essential compounds. In seed, the pool of free amino acids (FAAs) also contributes to alternative energy, desiccation, and seed vigor; thus, manipulating FAA levels can significantly impact a seed's nutritional qualities. While genome-wide association studies (GWAS) on branched-chain amino acids have identified some regulatory genes controlling seed FAAs, the genetic regulation of FAA levels, composition, and homeostasis in seeds remains mostly unresolved. Hence, we performed GWAS on 18 FAAs from a 313-ecotype Arabidopsis (Arabidopsis thaliana) association panel. Specifically, GWAS was performed on 98 traits derived from known amino acid metabolic pathways (approach 1) and then on 92 traits generated from an unbiased correlation-based metabolic network analysis (approach 2), and the results were compared. The latter approach facilitated the discovery of additional novel metabolic interactions and single-nucleotide polymorphism-trait associations not identified by the former approach. The most prominent network-guided GWAS signal was for a histidine (His)-related trait in a region containing two genes: a cationic amino acid transporter (CAT4) and a polynucleotide phosphorylase resistant to inhibition with fosmidomycin. A reverse genetics approach confirmed CAT4 to be responsible for the natural variation of His-related traits across the association panel. Given that His is a semiessential amino acid and a potent metal chelator, CAT4 orthologs could be considered as candidate genes for seed quality biofortification in crop plants.

Characterization of fermented seaweed sauce prepared from nori (Pyropia yezoensis)

High-salt content seaweed sauces were prepared for the first time using nori (Pyropia yezoensis) by fermentation and characterized. Components and taste of the two nori sauces (NSs) prepared separately were compared with those of soy and fish sauces. The NSs were rich in total nitrogen compounds (1.5gN/100ml on average) and potassium (880mg/100g), and had a unique free amino acid composition (e.g., taurine 617mg/100g), explaining their unique taste as evaluated by a taste sensing system. As for their food function, inhibitory activity of angiotensin-converting enzyme was observed. As for their food safety, arsenic was detected at a 0.8mg/100g level in total, but inorganic arsenic was not detected (<0.05mg/100g) and not regarded as a problem. Allergy-causing substances contained in wheat, soy beans, and crustaceans were not detected (<0.1mg/100g) with NSs. These results suggest that the nori sauce has a high potential as a novel nutritional source for humans.

Variability in chemical and microbiological profiles of long-ripened Caciocavallo cheeses.

Five protected designation of origin (PDO) Caciocavallo Silano and 6 non-PDO Caciocavallo cheeses, ripened for 6mo and collected in the 5 Italian regions of the PDO area (Apulia, Basilicata, Calabria, Campania, and Molise, Italy), were studied to assess their physico-chemical (pH, acidity, moisture, fat, ash, protein, and free amino acid composition) and microbiological profiles. Analyses evidenced a certain fluctuation of previous parameters among samples regardless of the kind of cheese evaluated (PDO and non-PDO). The PCR-denaturing gradient gel electrophoresis analysis performed on the DNA directly extracted from cheeses gave different results, but a low number of bands was always observed. Only one band, corresponding to the species Streptococcus thermophilus, was detectable in 1 PDO and in 2 non-PDO cheese samples, whose free amino acid content was the lowest. Analyses were repeated on experimental Caciocavallo cheeses. Specifically, 2 productions were made, one mimicking the industrial technology (pasteurized milk and selected starter culture) and one the artisanal technology (raw milk and natural whey starter). Results obtained on experimental cheeses at 6mo of ripening showed that industrial samples had lower amounts of total free amino acids then the artisanal ones (1,188.2 vs. 7,523.67mg/100 g of dry matter). Moreover, the PCR-denaturing gradient gel electrophoresis analysis evidenced the sole presence of S. thermophilus in the case of the industrial technology. These data sustain the hypothesis that, out of 11 cheeses analyzed previously, 1 PDO Caciocavallo Silano and 2 non-PDO Caciocavallo cheeses were obtained with the industrial technology. These results could be of help in the discrimination of PDO products, taking into account that the PDO production regulation does not allow the milk pasteurization, nor the use of selected starters.

Effects of long-term frozen storage on the compositions of free amino acids and nucleotide-related compounds of the coconut crab Birgus latro

This study examined the effects of long-term frozen storage (-20 °C for 5 months) of free amino acids (FAAs) and nucleotide-related compounds (NRCs) in muscle and hepatopancreas of the coconut crab Birgus latro. Although long-term frozen storage had little effect on FAA composition in muscle, the amounts of several FAAs increased in the hepatopancreas that may be the result of protein decomposition during the frozen storage. Long-term storage at -20°C significantly increased the amounts of disodium 5ʹ-inosine monophosphate (IMP) in muscle and hepatopancreas, resulting from the deaminase activity of 5ʹ-adenosine monophosphate (AMP) which deaminates AMP to IMP. Changes in FAAs and NRCs may result in changes in the flavor of muscle and hepatopancreas of frozen stored coconut crabs, both through altered amounts of each substance and synergistic interactions among substances.

Free amino acids, including canavanine, in the seeds from 32 Vicia species belonging to subgenus Vicilla

Abstract The free amino acid composition of the seeds from 32 Vicia species has been determined. Free amino acids ranged from 0.25 g/100 g flour in V. onobrychioides to 3.94 g/100 g flour in V. incana . Canavanine and metabolically related amino acids were the most abundant. Canavanine by itself was the most abundant in many species, especially those belonging to sections Cracca and Panduratae . Section Cracca includes the species with the highest contents in canavanine, going from as low as 0.09 g/100 g flour in V. sicula to as much as 3.27 g/100 g flour in V. incana . Our results show that several Vicia species are very rich in canavanine and may represent a source of this amino acid for functional applications.

Variability of biogenic amine and free amino acid concentrations in regionally produced goat milk cheeses

The free amino acid composition and biogenic amine content were analysed in pasteurised goat milk cheeses produced in different regions in Spain. These goat cheeses are made with pasteurised milk to which a mesophilic starter culture is added; they are enzymatically coagulated, uncooked, pressed cheeses. They have a firm texture with a slight but typical goat milk aroma and flavour. The total free amino acids varied markedly among the samples, ranging from 1400 to 28,000mgkg−1 DM (dry matter). Of the 20 amino acids analysed, the most abundant were leucine, proline, valine, glutamic acid, lysine, glutamine, ornithine and γ-aminobutyric acid, which accounted for over 60% of the total free amino acids. The goat milk cheeses presented low concentrations of biogenic amines, the most abundant being tyramine and/or histamine, with values ranging from 4.2 to 50.7 and from 10.2 to 60.5mgkg−1 DM, respectively. Total biogenic amine content ranged between 26.4mgkg−1 DM and 175.1mgkg−1 DM, and was always below the level that is considered dangerous for humans. Therefore, taking into consideration the concentrations of BAs, these goat milk cheeses, produced under good hygienic conditions, can be considered safe for consumers.

Free Amino Acid Composition of Korean Spinach (Spinacia oleracea) Cultivars as Influenced by Different Harvesting Time

BACKGROUND: There is lack of comprehensive compositional data of the amino acid profile of spinach with regard to different cultivars. A more detailed knowledge in this aspect will be of benefit in the future selection of spinach genotypes with improved nutritional quality. METHODS AND RESULTS: The effects of cultivar type (Jeoncheonhu, Sagyejul, Namdongcho and Mustang) and harvest time (79th, 116th and 145th days after sowing or DAS) on the concentrations of free amino acids in field-grown spinach (Spinacia oleracea) were examined. About 35 different free amino acids were detected and quantified by the amino acid analyzer. Glutamic acid and proline were identified as the major amino acids, while α -aminoadipic acid and α-aminobutyric acid were present in much lower concentrations. Spinach constituted 1468.4 mg/100 g total free amino acids (TAA), of which essential amino acids, neutral/acidic amino acids and sulphur containing amino acids constituted around 15, 45 and 2% of the TAA, respectively. The most limiting amino acids among the leafy vegetables-cysteine was recorded only in Mustang harvested at 116 DAS. Free amino acid contents did not differ significantly among the spinach cultivars and also at different harvest times. CONCLUSION: The data show that, either of the spinach cultivars, preferably Mustang harvested on or after 116 DAS can serve as a significant source of nutritionally relevant amino acids to meet the demand of the growing populations.

The study of the amino acid composition of the extracts obtained from cherry leaves and shoots, leaves of apricot and peach

Extracts were obtained from raw materials of cultivated plants from family Rosaceae and pharmacological screening was carried out. It was found that extract of cherry shoots showed diuretic activity higher than the comparator hypothiazide at a dose of 100 mg / kg, extracts from cherry and apricot leaves had significant anti-inflammatory activity in a dose of 25 mg / kg, extract from peach leaves showed immunotropic activity in low concentration of 0.4 mg / ml detected in vitro These extracts are promising for further study and creation of new medicines on their basis. Composition and content of free amino acids in the dry extracts obtained from the leaves and shoots of cherry, leaves of apricot and soft extract from peach leaves were determined by HPLC. The presence of 21 amino acids of which eight are essential - threonine, valine, isoleucine, leucine, phenylalanine, histidine, lysine and arginine, was established. Proline, asparagine, γ-aminobutyric and glutamic acids, arginine and alanine prevailed. All extracts were free from cystine and methionine and only extracts from the leaves of cherry and peach contained cysteine in small amount. The dry extract of cherry shoots had the largest amount of amino acids - 3154.2 mg / L, the lowest - the extract from apricot leaves - 605.9 mg / L.

Changes in the Composition of Free Amino Acid During Production of Pastirma Cured with Different Levels of Sodium Nitrite

Pastırma is a dry-cured meat product produced in many parts of the world. Pastırma has high-value animal protein. So, it is an important food of animal origin for the human diet. An intense proteolysis also occurs during pastırma production, and the amounts of free amino acids (FAA) increase. In this study, the effects of different nitrite levels on composition of FAA were determined during pastırma processing. At the curing stage of pastırma production, meat was treated with 50, 100 and 150 ppm sodium nitrite. Analysis were performed at the raw material, end of curing, end of second drying and pastırma. The nitrite levels (P < 0.01) and production stages (P < 0.01) had significant effects on the composition of FAA. Compared with control, the amounts of serine, threonine, tyrosine, histidine and lysine increased, while the amounts of glycine, glutamine and arginine decreased in the pastırma containing nitrite. The highest FAA amounts were found in the pastırma consisting nitrite. However, the lowest FAA amounts among the pastırma groups with nitrite were in the 150 ppm. Practical Applications This is the first study on determining the effect of usage nitrite on the composition of free amino acid (FAA) during pastırma processing and in the ready-to-eat pastırma. Proteolysis had an important effect on sensory properties of pastırma. The amounts of FAA increasing in the degradation affect on the desirable sensory properties in the final product, directly or transform different components. The results of this study can serve to increase of pastırma quality properties by the effect of nitrite on the composition of FAAs. In addition, results of this study will contribute significantly to efforts to reduce the usage of nitrite in the pastırma production.

Composition of free and peptide-bound amino acids in beef chuck, loin, and round cuts1,2

Meat is a food for humans. However, beef consumption in the United States has steadily declined by >14% over the past decade due to a variety of factors, including insufficient knowledge of animal protein. This study quantified all proteinogenic AA as well as nutritionally and physiologically significant nonproteinogenic AA and small peptides in beef cuts from 3 subprimals (chuck, round, and loin). Beef carcasses ( = 10) were selected at 3 commercial packing plants in the United States. Retail-cut samples were analyzed for the nitrogenous substances after acid, alkaline, or enzymatic hydrolysis and after deproteinization. In these chuck, round, and loin cuts, total amounts of glutamate (free plus peptide bound) were the highest (69-75 mg/g dry weight) followed by lysine, leucine, arginine, and glutamine in descending order. This is the first study to determine aspartate, asparagine, glutamate, and glutamine in meat proteins of any animal species. In all the beef samples evaluated, glutamine was the most abundant free AA (4.0-5.7 mg/g dry weight) followed by taurine, alanine, glutamate, and β-alanine. Additionally, samples from all beef cuts had high concentrations of anserine, carnosine, and glutathione, which were 2.8 to 3.7, 15.2 to 24.2, and 0.68 to 0.79 mg/g dry weight, respectively. Beef top loin steaks appear to provide higher protein nutrition values than top round steaks and under blade roasts, but all are excellent sources of proteinogenic AA as well as antioxidant AA and peptides to improve human growth, development, and health. Our findings may help guide future decisions regarding human and animal nutrition.

Changes in the community structure of free-living heterotrophic bacteria in the open tropical Pacific Ocean in response to microalgal lysate-derived dissolved organic matter.

Dissolved organic matter derived from phytoplankton (DOMP) can affect the bacterial biomass and community structure in aquatic ecosystems. Here, we examined the community response of free-living heterotrophic bacteria, with respect to cellular nucleic acid levels, to the DOMP lysates derived from three phytoplankton strains in the open tropical Pacific. The free amino acid (FAA) composition of each DOMP lysate differed among the microalgal strains. Terminal restriction fragment-length polymorphism analyses with 16S rRNA genes revealed that the community shifts of high nucleic acid (HNA) and low nucleic acid (LNA) bacteria varied significantly with the different DOMP lysate treatments. Furthermore, the FAA composition in DOMP lysates significantly affected the bacterial community shifts in HNA and LNA. Similarity percentage analysis using 16S rRNA gene deep-sequencing revealed that the DOMP lysates from the pelagophyte Pelagomonas calceolata caused relatively large community shifts with Alcaligenes predominating in the HNA fraction. In contrast, the DOMP lysate from the diatom Thalassiosira oceanica induced a community shift in the LNA fraction with a predominance of uncultured Actinobacteria Thus, the data indicate that the DOMP lysates from different microalgae constitute a primary factor altering the dominant bacterial groups in the open ocean.

Effects of algal food quality on free amino acid metabolism of Daphnia

Zooplankton frequently face dietary limitation caused by imbalances between their nutrient requirements and the nutrient content of their phytoplankton food. While insufficient nutrition is acknowledged to affect growth and reproduction of zooplankton, the effect of dietary limitation on other aspects of their metabolism remains poorly studied. One understudied biochemical response associated with nutrient stress is changes to the free amino acid (FAA) composition of body tissues resulting from changes in dietary supply. We examined changes in FAA composition in two cladoceran species (Daphnia magna and Daphnia pulex) in response to stress created by ecologically relevant food conditions: low food quantities, high algal carbon: nitrogen (C:N) ratios, and high algal C: phosphorus (P) ratios. We measured 14 FAA after extracting them from lyophilized whole Daphnia grown under these contrasting algal diets. Generally, low food quantity and low algal P increased body FAA content in both daphnid species while many essential FAA decreased due to N-limitation. While significant responses to diet were seen for each daphnid species, the nature of these responses depended on the type of nutritional stress, the FAA examined, and on the species. Non-parametric discriminant analysis exhibited a high predictive ability to classify unknown zooplankton into the correct diet category. The observed changes in body FAA profiles of Daphnia illustrate strong effects that algal food quality can have on the biochemistry of planktonic consumers. Furthermore these results demonstrate body FAA composition of zooplankton may provide an important source of information about zooplankton nutrient limitation especially combined with other nutrient-dependent molecular responses.

Prediction of individual milk proteins including free amino acids in bovine milk using mid-infrared spectroscopy and their correlations with milk processing characteristics

The aim of this study was to evaluate the effectiveness of mid-infrared spectroscopy in predicting milk protein and free amino acid (FAA) composition in bovine milk. Milk samples were collected from 7 Irish research herds and represented cows from a range of breeds, parities, and stages of lactation. Mid-infrared spectral data in the range of 900 to 5,000cm−1 were available for 730milk samples; gold standard methods were used to quantify individual protein fractions and FAA of these samples with a view to predicting these gold standard protein fractions and FAA levels with available mid-infrared spectroscopy data. Separate prediction equations were developed for each trait using partial least squares regression; accuracy of prediction was assessed using both cross validation on a calibration data set (n=400 to 591 samples) and external validation on an independent data set (n=143 to 294 samples). The accuracy of prediction in external validation was the same irrespective of whether undertaken on the entire external validation data set or just within the Holstein-Friesian breed. The strongest coefficient of correlation obtained for protein fractions in external validation was 0.74, 0.69, and 0.67 for total casein, total β-lactoglobulin, and β-casein, respectively. Total proteins (i.e., total casein, total whey, and total lactoglobulin) were predicted with greater accuracy then their respective component traits; prediction accuracy using the infrared spectrum was superior to prediction using just milk protein concentration. Weak to moderate prediction accuracies were observed for FAA. The greatest coefficient of correlation in both cross validation and external validation was for Gly (0.75), indicating a moderate accuracy of prediction. Overall, the FAA prediction models overpredicted the gold standard values. Near-unity correlations existed between total casein and β-casein irrespective of whether the traits were based on the gold standard (0.92) or mid-infrared spectroscopy predictions (0.95). Weaker correlations among FAA were observed than the correlations among the protein fractions. Pearson correlations between gold standard protein fractions and the milk processing characteristics of rennet coagulation time, curd firming time, curd firmness, heat coagulating time, pH, and casein micelle size were weak to moderate and ranged from −0.48 (protein and pH) to 0.50 (total casein and a30). Pearson correlations between gold standard FAA and these milk processing characteristics were also weak to moderate and ranged from −0.60 (Val and pH) to 0.49 (Val and K20). Results from this study indicate that mid-infrared spectroscopy has the potential to predict protein fractions and some FAA in milk at a population level.

Modulation of Pb-induced stress in Prosopis shoots through an interconnected network of signaling molecules, phenolic compounds and amino acids

Lead (Pb) is a hazardous heavy metal present in the environment which elicits oxidative stress in plants. To characterize the physiological and biochemical basis of Pb tolerance, Prosopis farcta seedlings were exposed to Hoagland's solutions at six different Pb concentrations (0, 80, 160, 320, 400 and 480 μM) for different periods of time. As expected, application of Pb significantly increased hydrogen peroxide (H2O2) content. In response, P. farcta deployed the antioxidative defence mechanisms with significantly higher activities of superoxide dismutase (SOD), enzymes related to H2O2 removal, and also the increases in proline as a solute marker of stress. Increases were observed in nitric oxide (NO) production which could also act in triggering defense functions to detoxify Pb. Enhanced phenylalanine ammonia-lyase (PAL) activity at early days of exposure to Pb was correlated with increases in phenolic compounds. Significant increases in phenolic acids and flavonoids; daidzein, vitexin, ferulic acid and salicylic acid were observed with Pb treatment. Furthermore, the stress effects were followed by changes in free amino acid content and composition. Aspartic acid and glycine content was increased but glutamic acid significantly decreased. It is likely that stress signal transduction by NO and H2O2 mediated defence responses to Pb by coordination of antioxidative system and metabolic pathways of phenylpropanoid and amino acids.

Macronutrient intake regulates sexual conflict in decorated crickets.

Sexual conflict results in a diversity of sex-specific adaptations, including chemical additions to ejaculates. Male decorated crickets (Gryllodes sigillatus) produce a gelatinous nuptial gift (the spermatophylax) that varies in size and free amino acid composition, which influences a female's willingness to fully consume this gift. Complete consumption of this gift maximizes sperm transfer through increased retention of the sperm-containing ampulla, but hinders post-copulatory mate choice. Here, we examine the effects of protein (P) and carbohydrate (C) intake on the weight and amino acid composition of the spermatophylax that describes its gustatory appeal to the female, as well as the ability of this gift to regulate sexual conflict via ampulla attachment time. Nutrient intake had similar effects on the expression of these traits with each maximized at a high intake of nutrients with a P:C ratio of 1:1.3. Under dietary choice, males actively regulated their nutrient intake but this regulation did not coincide with the peak of the nutritional landscape for any trait. Our results therefore demonstrate that a balanced intake of nutrients is central to regulating sexual conflict in G.sigillatus, but males are constrained from reaching the optima needed to bias the outcome of this conflict in their favour.

Influence of Malting on the Protein Composition of Triticale (× Triticosecale Wittmack) ‘Trigold’

Triticale (× Triticosecale Wittmack) is a promising cereal for malting and brewing owing to its high levels of α‐amylase and proteolytic activity and low gelatinization temperatures. However, almost no investigation about its protein modifications during malting has been conducted. In this work, triticale proteins during the malting process were separated and analyzed, first, according to their isoelectric point and molecular weight (MW) and, second, according to their solubility and MW. Moreover, the composition of free amino acids was determined. The results describe the modification changes of the different protein fractions during malting. Triticale proteins were found between 4,700 and 64,000. The majority of the proteins were characterized as having an isoelectric point between 5.08 and 6.63. The Osborne fractionation revealed an albumin band pattern of between 13,400 and 153,800, globulin from 12,700 to 152,300, gliadin from 14,500 to 230,100, and glutenin from 11,200 to 102,200. Free amino acids increased in concentration during malting except for asparagine, which decreased. Asparagine exhibited varying trends during malting. This paper contributes to the understanding of the protein modifications and metabolic changes during the malting process of triticale and indicates the potential of this cereal for the production of cereal‐based products.

Influence of Malting on the Protein Composition of Spelt (Triticum spelta L.) ‘Frankenkorn’

Although spelt has promising aptitudes for beer and beverage production, almost no investigation about its protein modifications during malting has been conducted. Spelt proteins during the malting process were separated and analyzed, first, according to the isoelectric point and molecular weight (MW) and, second, according to solubility and MW. Moreover, the composition of the free amino acid was determined. Spelt proteins could be divided into a total of 13 zones according to their isoelectric point and MW. Most of the present proteins (90%) had a MW between 35,000 and 60,000 and an isoelectric point between 5.84 and 9.52. The most prominent protein fraction was defined by an isoelectric point between 5.84 and 6.89 and a MW between 35,000 and 55,000. Generally, a protein degradation process during malting was found. The Osborne fractionation revealed an albumin band pattern between 14,000 and 131,700, globulin ranging from 13,400 to 130,500, gliadin from 14,500 to 220,800, and glutenin from 19,800 to 215,300. The free amino acid composition increased in concentration except for asparagine, which decreased during malting. This paper contributes to the understanding of the protein modifications and metabolic changes during the malting process of spelt and facilitates the determination of the potential of this cereal for the production of cereal‐based products.

Optimization of photosynthesis, growth, and biochemical composition of the microalga Rhodomonas salina—an established diet for live feed copepods in aquaculture

The cryptophyte Rhodomonas salina is widely used as feed for copepod cultures. However, culturing conditions to obtain high-quality algae have not yet been efficiently optimized. Therefore, we aimed to develop a cultivation protocol for R. salina to optimize its nutritional value and provide technical recommendations for later large-scale production in algal photobioreactors. We studied photosynthesis, growth, pigments, fatty acid (FA) and free amino acid (FAA) composition of R. salina cultured at different irradiances (10–300 μmol photons m−2 s−1) and nutrient availability (deficiency and excess). The optimal range of irradiance for photosynthesis and growth was 60–100 μmol photons m−2 s−1. The content of chlorophylls a and c decreased with increasing irradiance while phycoerythrin peaked at irradiances of 40–100 μmol photons m−2 s−1. The total FA content was maximal at optimal irradiances for growth, especially under nutrient deficiency. However, highly unsaturated fatty acids, desired components for copepods, were higher under nutrient excess. The total FAA content was highest at limiting irradiances (10–40 μmol photons m−2 s−1) but a better composition with a higher fraction of essential amino acids was obtained at saturated irradiances (60–140 μmol photons m−2 s−1). These results demonstrate that quality and quantity of FA and FAA of R. salina can be optimized by manipulating the irradiance and nutrient conditions. We suggest that R. salina should be cultivated in a range of irradiance 60–100 μmol photons m−2 s−1 and nutrient excess to obtain algae with high production and a balanced biochemical composition as feed for copepods.

Comparison of Carcass and Sensory Traits and Free Amino Acid Contents among Quality Grades in Loin and Rump of Korean Cattle Steer.

This study was performed to compare carcass traits, sensory characteristics, physiochemical composition, and contents of nucleotides, collagen, and free amino acids among quality grades (QG) and to understand the association between QG and above parameters in loin and rump of Korean cattle steer. Loin and rump samples were obtained from 48 Korean cattle steers with each of four QG (QG 1++, 1+, 1, and 2; average 32 months of age). Carcass weight and marbling score (MS) were highest in QG 1++, whereas texture score measured by a meat grader was highest in QG 2. A correlation analysis revealed that MS (r = 0.98; p<0.01) and fat content (r = 0.73; p<0.01) had strong positive correlations with QG and that texture had a strong negative correlation (r = −0.78) with QG. Fat content in loin was highest but protein and moisture contents were lowest in QG 1++. Our results confirmed that a major determinant of QG is the MS; thus, intramuscular fat content. The International Commission on Illumination L*, a*, and b* values in loin were highest in QG 1++. Numeric values of shear force in loin were lowest in QG 1++, whereas those of tenderness, juiciness, and overall acceptability tended to be highest in QG 1++ without statistical significance. QG was strongly correlated with juiciness (r = 0.81; p<0.01) and overall acceptability (r = 0.87; p<0.001). All sensory characteristics were higher (p<0.05) in loin than those in rump. Adenosine-5′-monophosphate (AMP) and inosine-5′-monophosphate (IMP) contents in both loin and rump did not differ among QGs. No nucleotide (AMP, IMP, inosine, hypoxanthine) was correlated with any of the sensory traits. Total, soluble, and insoluble collagen contents in loin were higher in QG 1++ than those in QG 1. All three collagens had lower content in loin than that in rump. All three collagens were positively correlated with tenderness, juiciness, and overall acceptability. Glutamic acid content did not significantly differ among the four QGs in either loin or rump. In conclusion, it is confirmed that QG is associated with sensory traits but nucleotide contents in beef may not be a major factor determining meat palatability in the present study.

Amino acid composition of the bushcricket spermatophore and the function of courtship feeding: Variable composition suggests a dynamic role of the nuptial gift

Nuptial gifts are packages of non-gametic material transferred by males to females at mating. These gifts are common in bushcrickets, where males produce a complex spermatophore consisting in a sperm-containing ampulla and an edible sperm-free spermatophylax. Two non-mutually exclusive hypotheses have been suggested to explain the function of the spermatophylax: the paternal investment hypothesis proposes that it represents a male nutritional investment in offspring; the mating effort hypothesis proposes that the spermatophylax maximizes the male's sperm transfer. Because gift production may represent significant energy expenditure, males are expected to adjust their investment relative to the perceived quality of the female. In this study, we first examined the free amino acid composition and protein-bound amino acid composition of the nuptial gift in the bushcricket, Ephippiger diurnus (Orthoptera: Tettigoniidae). Second, we investigated whether this composition was altered according to female age and body weight. Our study represents the first investigation of both free and protein-bound amino acid fractions of a bushcricket spermatophylax. We found that composition of the nuptial gift varied both qualitatively and quantitatively with respect to traits of the receiving female: older females received larger amounts of protein-bound amino acids (both essential and non-essential), less water and less free glycine. This result suggests that gift composition is highly labile in E. diurnus, and we propose that gift allocation might represent a form of cryptic male mate choice, allowing males to maximize their chances of paternity according to the risk of sperm competition that is associated with mate quality.