Abscisic Acid Promotes γ-Aminobutyric Acid Accumulation in Soybean Germinating Under Hypoxia-NaCl Stress

γ-aminobutyric acid is a nonprotein amino acid that accumulates in plants under stress. Abscisic acid is important for stress regulation via modulation of γ-aminobutyric acid function. Our results show that the expression of glutamate decarboxylase but not diamine oxidase gene is upregulated in germinating soybean treating treated with exogenous abscisic acid. There was a concomitant increase in glutamate decarboxylase and diamine oxidase activities and putrescine and spermine contents with a decrease in glutamate. These changes were abrogated by fluridone, an inhibitor of abscisic acid synthesis. In conclusion, abscisic acid treatment increases γ-aminobutyric acid accumulation by upregulating diamine oxidase gene expression and activation of glutamate decarboxylase and diamine oxidase activity in germinating soybean under hypoxia-salt stress.

Review: Dampak Negatif Indospicine dalam Indigofera sp. pada Ternak

ABSTRAKPakan merupakan aspek penting dari peternakan dan peningkatan produksi daging dapat dicapai melalui nutrisi dan manajemen yang tepat. Indigofera sp adalah salah satu spesies leguminosa hijauan yang potensial untuk ruminansia dan merupakan sumber penting protein, mineral, vitamin, serat serta memiliki palatabilitas tinggi. Genus Indigofera terdiri atas sekitar 700 spesies yang berbeda, banyak di antaranya adalah tanaman penting yang secara agronomis digunakan sebagai pakan ternak dan suplemen pakan. Namun, beberapa spesies Indigofera mengandung faktor antinutrisi dikenal sebagai indospicine yang merupakan asam amino nonprotein toksik (2,7- diamino-7-iminoheptanoic acid) dan diketahui bersifat hepatotoksik pada ruminansia. Ternak yang mengonsumsi Indigofera dilaporkan mengalami efek hepatotoksik dengan adanya lesi pada hati, efek teratogenik dan kematian embrio. Oleh karena itu, indospicine harus dipertimbangkan sebagai kemungkinan penyebab rendahnya penampilan ternak, khususnya penurunan berat badan dan gangguan reproduksi pada ruminansia yang diberi pakan indigofera sp dalam jumlah yang berlebihan. Di Indonesia spesies Indigofera zollingeriana merupakan pilihan paling tepat untuk dibudidayakan dan dikembangkan sebagai pakan ternak rumiansia karena memiliki kandungan indospicine yang rendah untuk menghilangkan kejadian keracunan indospicine.Kata kunci: faktor antinutrisi, hepatotoksik, indigofera, indospicineABSTRACTThe feed is an important aspect of animal production, an increase in meat production can be achieved through proper nutrition and good management. The Indigofera sp is one of the potential forage legume species which are important sources of protein, minerals, vitamins, fiber, and has high palatability that provide essential nutrients for ruminants. The Indigofera genus contains approximately 700 different species, many of which are agronomically important plants that are used as grazing forages and feed supplements. Some Indigofera species, however, contain antinutritional factors (ANF) known as indospicine, a toxic nonprotein amino acid (2,7- diamino-7-iminoheptanoic acid) and is thought to be hepatotoxic in ruminants. Cattle and sheep consuming Indigofera have been reported to experience both hepatotoxic effects with associated liver lesions, and also teratogenic and embryo-lethal effects. Therefore, indospicine should be considered as a possible cause of animal poor performance, particularly reduced weight gain and reproductive disorders in ruminants that are fed with excessive amounts of indigofera sp. in Indonesia Indigofera zollingeriana species are the most appropriate choice to be cultivated and developed as ruminat livestock feed because they have a low indospicine content to eliminate the incidence of indospicine poisoning.Keywords: antinutritional factor, hepatotoxic, Indigofera sp, indospicine

Homocysteine Modification in Protein Structure/Function and Human Disease

Epidemiological studies established that elevated homocysteine, an important intermediate in folate, vitamin B12, and one carbon metabolism, is associated with poor health, including heart and brain diseases. Earlier studies show that patients with severe hyperhomocysteinemia, first identified in the 1960s, exhibit neurological and cardiovascular abnormalities and premature death due to vascular complications. Although homocysteine is considered to be a nonprotein amino acid, studies over the past 2 decades have led to discoveries of protein-related homocysteine metabolism and mechanisms by which homocysteine can become a component of proteins. Homocysteine-containing proteins lose their biological function and acquire cytotoxic, proinflammatory, proatherothrombotic, and proneuropathic properties, which can account for the various disease phenotypes associated with hyperhomocysteinemia. This review describes mechanisms by which hyperhomocysteinemia affects cellular proteostasis, provides a comprehensive account of the biological chemistry of homocysteine-containing proteins, and discusses pathophysiological consequences and clinical implications of their formation.

L-DOPA Trends in Different Tissues at Early Stages of Vicia faba Growth: Effect of Tyrosine Treatment

The nonprotein amino acid Levo-3,4-dihydroxyphenylalanine (L-DOPA) has insecticidal, allelochemical, and antiparkinsonian effects. The aim of this research was to assess L-DOPA content in different tissues of Vicia faba (cv. Super Agua Dulce), and to verify if treatment with the phenolic amino acid L-4-hydroxyphenylalanine (tyrosine) had an effect on such content. Under light germination, control and tyrosine-treated early seedling stages of V. faba were studied and L-DOPA was quantified spectrophotometrically (Arnow’s method) and by high-performance thin-layer chromatography (HPTLC), as well. Additionally, tyrosinase (TYROX) and guaiacol peroxidase (GPX) activities (considered markers of a phenolic compounds metabolism) were quantified as germination proceeded. Different organs (roots, sprouts, and seeds) and different developmental stages were considered. Steady high L-DOPA concentrations were found in untreated sprouts and roots compared to seeds, as time progressed. While TYROX activity was not detected in these experiments, GPX had diverse trends. In control tissues, GPX increased in seed tissue as germination progressed, whereas in roots and sprouts, a decreasing GPX activity was observed. Tyrosine exposure decreased L-DOPA content, and decreased or did not change GPX activity (depending on the organ). Both Arnow’s and HPTLC methods were consistent in terms of tendencies, except for the scarce contents found in seeds, in which HPTLC was more sensitive. The richest source of L-DOPA was found in shoots (untreated), reaching as high as 125 mg g−1 DW (12% in DW) (the highest content reported in fava bean seedlings until now), whereas the smallest L-DOPA content was found in seeds. The importance of light germination conditions is discussed in terms of L-DOPA yield and from a physiological perspective. It is concluded that V. faba (cv. Super Agua Dulce) shoots are a good source of L-DOPA and that tyrosine addition (0.55 mM) decreases L-DOPA content in actively growing tissues (shoots and roots).

Alteration of Mevalonate Pathway in Rat Splenic Lymphocytes: Possible Role in Cytokines Secretion Regulated by L-Theanine

L-Theanine is a nonprotein amino acid in tea, and its immunomodulatory function has been confirmed. This study aimed to investigate the effect of L-theanine addition on cytokines secretion in rat splenic lymphocytes and explore its potential immunomodulatory effects on the mevalonate biosynthetic pathway. Our results showed that L-theanine treatment did not influence the proliferation and division indexes of the splenic lymphocytes subsets. Interestingly, L-theanine treatment had regulated the contents of IFN-γ, IL-2, IL-4, IL-10, IL-12, and TNF-α (P<0.001) except IL-6 and upregulated the mRNA and protein expression of Ras-related protein Rap-1A (Rap1A), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and farnesyl diphosphate synthase (FDPs) (P<0.001). Additionally, there was a positive correlation between Rap1A and HMGCR proteins expression and IFN-γ, IL-4, and IL-6 levels. In conclusion, L-theanine regulated the secretion of cytokines probably by activating expression of Rap1A and HMGCR proteins involved in the mevalonate biosynthetic pathway in rat splenic lymphocytes. Therefore, L-theanine might be a promising potential drug candidate as immunopotentiator.

A New Strategy for Production of 5-Aminolevulinic Acid in Recombinant Corynebacterium glutamicum with High Yield

ABSTRACT5-Aminolevulinic acid (ALA), a nonprotein amino acid involved in tetrapyrrole synthesis, has been widely applied in agriculture, medicine, and food production. Many engineered metabolic pathways have been constructed; however, the production yields are still low. In this study, several 5-aminolevulinic acid synthases (ALASs) from different sources were evaluated and compared with respect to their ALA production capacities in an engineeredCorynebacterium glutamicumCgS1 strain that can accumulate succinyl-coenzyme A (CoA). A codon-optimized ALAS fromRhodobacter capsulatusSB1003 displayed the best potential. Recombinant strain CgS1/pEC-SB produced 7.6 g/liter ALA using a mineral salt medium in a fed-batch fermentation mode. Employing two-stage fermentation, 12.46 g/liter ALA was produced within 17 h, with a productivity of 0.73 g/liter/h, in recombinantC. glutamicum. Through overexpression of the heterologous nonspecific ALA exporter RhtA fromEscherichia coli, the titer was further increased to 14.7 g/liter. This indicated that strain CgS1/pEC-SB-rhtA holds attractive industrial application potential for the future.IMPORTANCEIn this study, a two-stage fermentation strategy was used for production of the value-added nonprotein amino acid 5-aminolevulinic acid from glucose and glycine in a generally recognized as safe (GRAS) host,Corynebacterium glutamicum. The ALA titer represented the highest in the literature, to our knowledge. This high production capacity, combined with the potential easy downstream processes, made the recombinant strain an attractive candidate for industrial use in the future.

Alliin is a suicide substrate ofCitrobacter freundiimethionine γ-lyase: structural bases of inactivation of the enzyme

The interaction ofCitrobacter freundiimethionine γ-lyase (MGL) and the mutant form in which Cys115 is replaced by Ala (MGL C115A) with the nonprotein amino acid (2R)-2-amino-3-[(S)-prop-2-enylsulfinyl]propanoic acid (alliin) was investigated. It was found that MGL catalyzes the β-elimination reaction of alliin to form 2-propenethiosulfinate (allicin), pyruvate and ammonia. The β-elimination reaction of alliin is followed by the inactivation and modification of SH groups of the wild-type and mutant enzymes. Three-dimensional structures of inactivated wild-type MGL (iMGL wild type) and a C115A mutant form (iMGL C115A) were determined at 1.85 and 1.45 Å resolution and allowed the identification of the SH groups that were oxidized by allicin. On this basis, the mechanism of the inactivation of MGL by alliin, a new suicide substrate of MGL, is proposed.