Identification and evolution of a diterpenoid phytoalexin oryzalactone biosynthetic gene in the genus Oryza.

The natural variation of plant-specialized metabolites represents the evolutionary adaptation of plants to their environments. However, the molecular mechanisms that account for the diversification of the metabolic pathways have not been fully clarified. Rice plants resist attacks from pathogens by accumulating diterpenoid phytoalexins.

Molecular identification of a laccase that catalyzes the oxidative coupling of a hydroxycinnamic acid amide for hordatine biosynthesis in barley.

Plants produce dimerized phenolic compounds as secondary metabolites. Hordatine A (HA), a dehydrodimer of p-coumaroylagmatine (pCA), is an antifungal compound accumulated at high levels in young barley (Hordeum vulgare) seedlings. The enzyme responsible for the oxidative dimerization of pCA, which is the final step of the hordatine biosynthetic pathway, has not been identified.

NAD+ enhances the activity and thermostability of S-adenosyl-L-homocysteine hydrolase from Pyrococcus horikoshii OT3.

S-Adenosyl-L-methionine (SAM) and S-adenosyl-L-homocysteine (SAH) are important biochemical intermediates. SAM is the major methyl donor for diverse methylation reactions in vivo. The SAM to SAH ratio serves as a marker of methylation capacity.

Production and characterization of cyanocobalamin-enriched tomato (Solanum lycopersicum) fruits grown using hydroponics.

Background: Vitamin B is an essential vitamin that is absent in plant-derived foods such as fruits and vegetables. This can result in an increased risk of developing vitamin B deficiency in strict vegetarians (vegans). There are several studies that have aimed to enhance nutrients in food crops.

Dityrosine Crosslinking of Collagen and Amyloid-β Peptides Is Formed by Vitamin B Deficiency-Generated Oxidative Stress in .

(1) Background: Vitamin B deficiency in results in severe oxidative stress and induces morphological abnormality in mutants due to disordered cuticle collagen biosynthesis. We clarified the underlying mechanism leading to such mutant worms due to vitamin B deficiency. (2) Results: The deficient worms exhibited decreased collagen levels of up to approximately 59% compared with the control.

Lemon myrtle extract inhibits lactate production by Streptococcus mutans.

Backhousia citriodora (lemon myrtle) extract has been found to inhibit glucansucrase activity, which plays an important role in biofilm formation by Streptococcus mutans. In addition to glucansucrase, various virulence factors in S. mutans are involved in the initiation of caries.

Effects of Vitamin B Deficiency on Amyloid-β Toxicity in .

High homocysteine (Hcy) levels, mainly caused by vitamin B deficiency, have been reported to induce amyloid-β (Aβ) formation and tau hyperphosphorylation in mouse models of Alzheimer's disease. However, the relationship between B deficiency and Aβ aggregation is poorly understood, as is the associated mechanism. In the current study, we used the transgenic strain GMC101, which expresses human Aβ peptides in muscle cells, to investigate the effects of B deficiency on Aβ aggregation-associated paralysis.

High-dose folic acid supplementation results in significant accumulation of unmetabolized homocysteine, leading to severe oxidative stress in Caenorhabditis elegans.

Using Caenorhabditis elegans as a model animal, we evaluated the effects of chronical supplementation with high-dose folic acid on physiological events such as life cycle and egg-laying capacity and folate metabolism. Supplementation of high-dose folic acid significantly reduced egg-laying capacity. The treated worms contained a substantial amount of unmetabolized folic acid and exhibited a significant downregulation of the mRNAs of cobalamin-dependent methionine synthase reductase and 5,10-methylenetetrahydrofolate reductase.

L-Ascorbate Biosynthesis Involves Carbon Skeleton Rearrangement in the Nematode .

Ascorbate (AsA) is required as a cofactor and is widely distributed in plants and animals. Recently, it has been suggested that the nematode also synthesizes AsA. However, its biosynthetic pathway is still unknown.

5-hydroxymethyl-2-furaldehyde purified from Japanese pear ( Nakai cv. Nijisseiki) juice concentrate inhibits melanogenesis in B16 mouse melanoma cells.

Pear juice concentrate prepared by boiling Japanese pear ( Nakai cv. Nijisseiki) juice can significantly inhibit the activity of tyrosinase, a key enzyme in melanin synthesis in human skin. Using the ethanol extract of pear juice concentrate, we homogeneously purified an active compound that was identified as 5-hydroxymethyl-2-furaldehyde (5-HMF) through H- and C-NMR and mass spectroscopy.

Food Additives (Hypochlorous Acid Water, Sodium Metabisulfite, and Sodium Sulfite) Strongly Affect the Chemical and Biological Properties of Vitamin B in Aqueous Solution.

Food additives, such as hypochlorous acid water, sodium metabisulfite, and sodium sulfite, strongly affect the chemical and biological properties of vitamin B (cyanocobalamin) in aqueous solution. When cyanocobalamin (10 μmol/L) was treated with these compounds, hypochlorous acid water (an effective chlorine concentration of 30 ppm) rapidly reacted with cyanocobalamin. The maximum absorptions at 361 and 550 nm completely disappeared by 1 h, and vitamin B activity was lost.

Growth Response of Lactobacillus rhamnosus Chloramphenicol-Resistant Strain ATCC 27773 to Pteroyl-Mono- and -Di-Glutamates.

This study investigated the effect of various concentrations of pteroyl-mono-γ-glutamate (PteGlu) and pteroyl-di-γ-glutamate (PteGlu) on the growth of Lactobacillus rhamnosus strains ATCC 7469 (wild-type strain) and ATCC 27773 (chloramphenicol-resistant strain) used for folate microbiological assays. At concentrations of 0.025-0.

Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley.

Phytoalexins are inducible antimicrobial metabolites in plants, and have been indicated to be important for the rejection of microbial infection. HPLC analysis detected the induced accumulation of three compounds - in barley () roots infected by , the causal agent of Fusarium root rot. Compounds - were identified as cinnamic acid amides of 9-hydroxy-8-oxotryptamine, 8-oxotryptamine, and (1-indol-3-yl)methylamine, respectively, by spectroscopic analysis.

Natural variation in the expression and catalytic activity of a naringenin 7-O-methyltransferase influences antifungal defenses in diverse rice cultivars.

Phytoalexins play a pivotal role in plant-pathogen interactions. Whereas leaves of rice (Oryza sativa) cultivar Nipponbare predominantly accumulated the phytoalexin sakuranetin after jasmonic acid induction, only very low amounts accumulated in the Kasalath cultivar. Sakuranetin is synthesized from naringenin by naringenin 7-O-methyltransferase (NOMT).

Involvement of Spermidine in the Reduced Lifespan of During Vitamin B Deficiency.

Vitamin B deficiency leads to various symptoms such as neuropathy, growth retardation, and infertility. Vitamin B functions as a coenzyme for two enzymes involved in amino acid metabolisms. However, there is limited information available on whether amino acid disorders caused by vitamin B deficiency induce such symptoms.

Variation of diterpenoid phytoalexin oryzalexin A production in cultivated and wild rice.

Rice (Oryza sativa) leaves accumulate phytoalexins in response to pathogen attack. The major phytoalexins in rice are diterpenoids such as oryzalexins, momilactones, and phytocassanes. We measured the amount of oryzalexin A in leaves irradiated by UV light, treated with jasmonic acid, or inoculated with conidia of Bipolaris oryzae in the japonica cultivar Nipponbare and the indica cultivar Kasalath.

Induction of defense responses by extracts of spent mushroom substrates in rice.

We investigated the effect of treatment with hot water extracts from the spent mushroom substrates (SMSs) of and on the resistance of rice leaves to infection. The spraying of the SMS extracts clearly suppressed the development of lesions caused by infection. The accumulation of phytoalexins momilactones A and B, oryzalexin A, and sakuranetin was markedly induced by the spraying of extracts.

A lemon myrtle extract inhibits glucosyltransferases activity of Streptococcus mutans.

Streptococcus mutans is a bacterium found in human oral biofilms (dental plaques) that is associated with the development of dental caries. Glucosyltransferases (GTFs) are key enzymes involved in dental plaque formation, and compounds that inhibit their activities may prevent dental caries. We developed a screening system for GTF-inhibitory activities, and used it to profile 44 types of herbal tea extracts.

Yolk of the Century Egg (Pidan) Contains a Readily Digestible Form of Free Vitamin B.

In this study, we determined the vitamin B content of commercially available century eggs (pidan) and characterized their vitamin B compositions in detail. The egg yolk and white of century eggs (each 100 g wet weight) contained 1.9±0.

Distribution of the tryptophan pathway-derived defensive secondary metabolites gramine and benzoxazinones in Poaceae.

The Poaceae is a large taxonomic group consisting of approximately 12,000 species and is classified into 12 subfamilies. Gramine and benzoxazinones (Bxs), which are biosynthesized from the tryptophan pathway, are well-known defensive secondary metabolites in the Poaceae. We analyzed the presence or absence of garamine and Bxs in 64 species in the Poaceae by LC-MS/MS.

Vitamin B deficiency results in severe oxidative stress, leading to memory retention impairment in Caenorhabditis elegans.

Oxidative stress is implicated in various human diseases and conditions, such as a neurodegeneration, which is the major symptom of vitamin B deficiency, although the underlying disease mechanisms associated with vitamin B deficiency are poorly understood. Vitamin B deficiency was found to significantly increase cellular HO and NO content in Caenorhabditis elegans and significantly decrease low molecular antioxidant [reduced glutathione (GSH) and L-ascorbic acid] levels and antioxidant enzyme (superoxide dismutase and catalase) activities, indicating that vitamin B deficiency induces severe oxidative stress leading to oxidative damage of various cellular components in worms. An NaCl chemotaxis associative learning assay indicated that vitamin B deficiency did not affect learning ability but impaired memory retention ability, which decreased to approximately 58% of the control value.

Characterization and Quantitation of Vitamin B Compounds in Various Chlorella Supplements.

Vitamin B was determined and characterized in 19 dried Chlorella health supplements. Vitamin contents of dried Chlorella cells varied from <0.1 μg to approximately 415 μg per 100 g of dry weight.

Functions of heat shock transcription factors involved in response to photooxidative stresses in Arabidopsis.

Because plants are continually exposed to various environmental stresses, they possess numerous transcription factors that regulate metabolism to adapt and acclimate to those conditions. To clarify the gene regulation systems activated in response to photooxidative stress, we isolated 76 high light and heat shock stress-inducible genes, including heat shock transcription factor (Hsf) A2 from Arabidopsis. Unlike yeast or animals, more than 20 genes encoding putative Hsfs are present in the genomes of higher plants, and they are categorized into three classes based on their structural characterization.

Transcriptional control of vitamin C defective 2 and tocopherol cyclase genes by light and plastid-derived signals: the partial involvement of GENOMES UNCOUPLED 1.

Previous findings have suggested that light and plastid-derived signals are involved in the regulation of biosynthetic pathways for l-ascorbic acid (AsA) and tocopherols (Toc). Photosynthetic electron transport (PET) activity, plastid gene expression (PGE), and the tetrapyrrole metabolism have been identified as signals that regulate nuclear gene expression through the GENOMES UNCOUPLED 1 (GUN1) protein. Here, we examined the effects of disrupting GUN1 on these pathways.

Functional and structural characteristics of methylmalonyl-CoA mutase from Pyrococcus horikoshii.

Methylmalonyl-CoA mutase (MCM) requires 5'-deoxyadenosylcobalamin (AdoCbl) as a cofactor and is widely distributed in organisms from bacteria and animals. Although genes encoding putative MCMs are present in many archaea, they are separately encoded in large and small subunits. The large and small subunits of archaeal MCM are similar to the catalytic and AdoCbl-binding domains of human MCM, respectively.