Plants synthesize isopentenyl diphosphate (IPP) via the mevalonate pathway and the methylerythritol phosphate (MEP) pathway. IPP is condensed to its allylic isomer, dimethylallyl diphosphate, to yield geranylgeranyl diphosphate, a common precursor for the production of cyclic diterpenoids. Studies of subcellular localization and of transgenic plants defective in the enzymes involved in the pathway have revealed that the synthesis processes of plastidic diterpenoids are metabolically separated in the plastids. Ditepenoid phytoalexins are synthesized through the plastidic MEP pathway in rice. The biosynthetic genes responsible for diterpenoid phytoalexins are clustered on the rice chromosomes, and the expression of them was coordinately regulated under stress conditions. Furthermore, a basic leucine zipper transcription factor, OsTGAP1, which is induced by the fungal chitin oligosaccharide elicitor, was identified as a key regulator of coordinated expression of the clustered biosynthetic genes for phytoalexin production in rice.

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ε-Poly-L-lysine (ε-PL) consists of 25–35 L-lysine residues with linkages between the α-carboxyl groups and the ε-amino groups. It exhibits antimicrobial activity against a spectrum of microorganisms, including bacteria and fungi. Because of its high levels of safety and biodegradability, it is used as a food preservative in several countries. We recently identified an ε-PL synthetase (Pls) as a membrane protein, and investigated the catalytic mechanism. Pls was found to be an unusual non-ribosomal peptide synthetase (NRPS)-like peptide synthetase producing ε-PL with chain-length diversity. In addition, transcriptional analysis of pls and a kinetic study of Pls further suggested that the Pls catalytic function is regulated by intracellular ATP, high levels of which are required for full enzymatic activity. Furthermore, it was found that acidic pH conditions during ε-PL fermentation are necessary for the accumulation of intracellular ATP, rather than inhibition of the ε-PL-degrading enzyme.

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The relationship between cyclooctadepsipeptides and their anthelmintic efficacy was examined by converting the natural products, PF1022A, PF1022E and PF1022H. Some analogues substituted at the para position of the phenyllactate moiety showed higher or equivalent activity against the parasitic nematode, Ascaridia galli in chicken when compared with the parent compounds. It is suggested that lipophilicity and the polar surface area, in addition to structural requirements of the derivatives, influenced the anthelmintic efficacy in vivo.

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Glucopyranose analogues carrying a bicyclo[4.1.0]heptane framework (4) and the diastereomer of the cyclopropane moiety were synthesized as the unit for molecular probes to mimic the unstable transition state conformation of the glucopyranose ring in enzymatic hydrolysis. The synthesis features differentiation of the α- and β-stereoselectivity in cyclopropanation of the corresponding cyclohexene derivative (5).

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The new kaurane diterpene, ent-3β-butanoyloxykaur-15-en-17-ol, and four known kaurane diterpenes were isolated from the bulbs of Fritillaria ebeiensis. Their structures were elucidated on the basis of extensive spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1-D and 2-D NMR). All the isolates showed neuroprotective effects against MPP⁺-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.

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Using a homology-based PCR strategy, we identified a cDNA with sequence similarity to linalool synthase from lemon myrtle. Functional expression of the cDNA (designated BcLS) gene in Escherichia coli yielded an active enzyme capable of catalyzing the conversion of geranyl diphosphate to (−)-linalool, i.e., an acyclic monoterpene alcohol, and to lesser amounts of cyclic monoterpenes. The kinetic parameters of BcLS were similar to those of synthases producing cyclic monoterpenes. PCR analysis revealed that the BcLS gene transcript was ubiquitously expressed in lemon myrtle and was upregulated in response to jasmonic acid treatment. Although the physiological role of neryl diphosphate (NPP) dependency of BcLS remains unclear, the cyclization activity of BcLS was enhanced when NPP was used as substrate, resulting in predominant production of cyclic monoterpenes. These findings indicate that BcLS has novel specificity and kinetic parameters, but its physiological responses to stresses such as insect damage appear to be similar to known linalool synthases.

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The protective effects of interleukin-22 (IL-22) on acute alcohol-induced liver injury were investigated. Mice were gavaged with 7 doses of alcohol (56% wt/vol, 15.2 mL/kg of body weight for each dose) over the 24 h, and IL-22 (0.5 mg/kg BW) was given to the mice by injection into the tail vein 1 h after alcohol administration. The results indicated that acute alcohol administration caused prominent hepatic microvesicular steatosis and an elevation of serum transaminase activities, induced a significant decrease in hepatic glutathione in conjunction with enhanced lipid peroxidation, and increased hepatocyte apoptosis as well as hepatic TNF-alpha production. IL-22 treatment attenuated these adverse changes induced by acute alcohol administration. The protective effects of IL-22 on alcohol-induced hepatotoxicity were due mainly to its anti-inflammatory, anti-oxidant, and anti-apoptotic features.

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Electrolyzed reduced water (ERW) contains a large amount of molecular hydrogen and a small amount of Pt nanoparticles (Pt NPs). We have found that ERW significantly extended the lifespan of Caenorhabditis elegans in a novel culture medium designated Water Medium. In this study, we found that synthetic Pt NPs at ppb levels significantly extended the nematode lifespan and scavenged reactive oxygen species (ROS) in the nematode induced by paraquat treatment. In contrast, a high concentration of dissolved molecular hydrogen had no significant effect on the lifespan of the nematode. These findings suggest that the Pt NPs in ERW, rather than the molecular hydrogen, extend the longevity of the nematode, at least partly by scavenging ROS.

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Previous studies have suggested an association of hyperhomocysteinemia-induced vascular pathology with enhanced apoptotic potential of endothelial progenitor cells in patients with coronary heart disease. Our results indicate that 500 μmol/L homocysteine induced endothelial progenitor cell apoptosis and activation of caspase-3, both of which were abolished by 100 μmol/L and 200 μmol/L salubrinal, an agent that prevents endoplasmic reticulum stress-induced apoptosis. The addition of 500 μmol/L homocysteine caused a release of Ca²⁺ from intracellular stores, and enhanced phosphor-eukaryotic initiation factor 2α phosphorylation at Ser51 and the expression of a glucose-regulated protein of 78 kDa and a C/EBP homologous protein independently of extracellular Ca²⁺. These effects of homocysteine on endothelial progenitor cells were significantly greater in patients with coronary heart disease than in healthy donors. These findings suggest that homocysteine induces endoplasmic reticulum stress-mediated activation of caspase-3 in endothelial progenitor cells, an event that is enhanced in patients with coronary heart disease. Furthermore, enhanced endoplasmic reticulum stress-mediated activation of caspase-3 in endothelial progenitor cells might be involved in hyperhomocysteinemia-associated vascular pathology.

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Isoegomaketone (IK) is an essential oil component of Perilla frutescens (L.), but the mechanism by which IK induces apoptosis has never been studied. The purpose of this study was to elucidate the IK-induced apoptotic pathway in DLD1 human colon cancer cells. We observed that IK treatment over 24 h significantly inhibited cell viability in a dose-dependent manner. We also found that IK triggered cleavage of PARP. Moreover, IK treatment resulted in cleavage of caspase-8, -9, and -3 in a dose- and time-dependent manner. IK treatment also resulted in cleavage of Bid and translocation of Bax, and triggered the release of cytochrome c from the mitochondria to the cytoplasm. Furthermore, it resulted in the translocation of apoptosis inducing factor (AIF), a caspase-independent mitochondrial apoptosis factor, from the mitochondria into the nucleus. Overall, these results suggest that IK induces apoptosis through caspase-dependent and capase-independent pathways in DLD1 cells.

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Bacillus subtilis LmrA and QdoR (formerly YxaF) are paralogous transcriptional regulators that repress their regulon comprising the lmrAB operon, the qdoR gene, and the qdoI-yxaH operon, by binding to the LmrA/QdoR boxes located in the promoter regions. Detachment of them followed by derepression of the target genes is induced by certain flavonoids. To identify the residues critical to the ligand response in QdoR, we selected eight residues based on structural information, produced eight single-mutated QdoRs in which each residue was replaced with alanine, and evaluated their capacities for DNA binding and the flavonoid response by gel retardation analysis. The three mutants, carrying the alanine substitution at Phe87, Trp131, or Phe135, showed features distinctly different from those of the wild type and from each other. We further examined the in vivo function of the mutant with alanine substitution at Trp131 by reporter assay. This largely supported the corresponding in vitro results. The in vitro and in vivo data suggest that Phe87, Trp131, and Phe135, forming a hydrophobic cluster in QdoR, play crucial roles in the DNA binding, flavonoid accommodation, and/or conformational change triggered by ligand binding.

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A bi-cistronic baculovirus-insect/larval system containing a polyhedron promoter, an internal ribosome entry site (IRES), and an egfp gene was developed as a cost-effective platform for the production of recombinant human interferon gamma (rhIFN-γ). There was no significant difference between the amounts of rhIFN-γ produced in the baculovirus-infected Spodoptera frugiferda 21 cells grown in serum-free medium and the serum-supplemented medium, while the Trichoplusia ni (T. ni) and Spodoptera exigua (S. exigua) larvae afforded rhIFN-γ amounting to 1.08±0.04 and 9.74±0.35 μg/mg protein respectively. The presence of non-glycosylated and glycosylated rhIFN-γ was confirmed by immunoblot and lectin blot. The immunological activity of purified rhIFN-γ, with 96% purity by Nickel (II)-nitrilotriacetic acid (Ni-NTA) affinity chromatography, was similar to that commercially available. Moreover, the rhIFN-γ protein from T. ni had more potent antiviral activity. These findings suggest that this IRES-based expression system is a simple and inexpensive alternative for large-scale protein production in anti-viral research.

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The DNA replication mechanism has been well established for eutherian mammals (placental mammals such as humans, mice, and cattle), but not, to date, for metatherian mammals (marsupials such as kangaroos, koalas, and opossums). In this study, we found that dehydroaltenusin, a selective inhibitor of mammalian (eutherian) DNA polymerase α, clearly suppressed the growth of metatherian (opossum and rat kangaroo) cultured cells. In cultured opossum (OK) cells, dehydroaltenusin also suppressed the progression of DNA replication. These results suggest that dehydroaltenusin inhibits metatherian as well as eutherian DNA replication. Dehydroaltenusin treatment of OK cells engendered fluctuations in the numbers of chromosomes in the OK cells as well as inhibition of cell growth and DNA replication. This suggests that partial inhibition of DNA replication by dehydroaltenusin causes chromosomal instability in cultured cells.

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Bacteriorhodopsin (BR) is a retinal protein that functions as a light-driven proton pump. In this study, six novel mutants including K41E and D102K, were obtained to verify or rule out the possibility that residues Lys41 and Asp102 are determinants of the time order of proton release and uptake, because we found that the order was reversed in another retinal protein archaerhodopsin 4 (AR4), which had different 41th and 102th residues. Our results rule out that possibility and confirm that the pK_a of the proton release complex (PRC) determines the time order. Nevertheless, mutations, especially D102K, were found to affect the kinetics of proton uptake substantially and the pK_a of Asp96. Compared to the wild-type BR (BR-WT), the decay of the M intermediate and proton uptake in the photocycle was slowed about 3-fold in D102K. Hence those residues might be involved in proton uptake and delivery to the internal proton donor.

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Free divalent ions of copper (Cu) are capable of generating radical species such as hydroxyl radicals in the presence of hydrogen peroxide or ascorbic acid through Harbor-Weiss-like reactions under physiological conditions. It has been reported that radical-mediated damage to DNA molecules in animal cells leads to programmed cell death. Hence it is important to seek for methods to prevent Cu-mediated DNA damage. In this study we identified on effect of Cu binding of short peptides (chiefly Gly-Gly-His tripeptide) in the prevention of DNA degradation caused by Cu-mediated reactions in the presence of hydrogen peroxide and of ascorbic acid.

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In this study, we investigated the effect of fish oil on gene expression in the cerebral cortex, and found that 5-aminolevulinate synthase 2 (ALAS2) mRNA expression was up-regulated by fish oil feeding. ALAS2 promoter activity was found to be regulated by retinoic acid. Our results suggest that fish oil modulates neuronal functions via heme synthesis.

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We established an Na₂S-free, large-scale overexpression system of deriving CODH II from thermophilic bacterium Carboxydothermus hydrogenoformans in Escherichia coli using a large-scale fermentor. Recombinant-CODH II showed a CO oxidation activity of 9,600 U/mg. In addition, recombinant-CODH II exhibited considerable CO₂ reduction activity, of 16.9 U/mg.

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We evaluated the cytotoxicity of surfactants in human cells. Synthetic surfactants showed different cytotoxicity levels depending on their structures. The cytotoxicity of commercial washing products was determined mainly by the contents of surfactants. All of them induced premature senescence in normal cells, but not in tumor-derived or immortalized cells, under sublethal conditions. Residual surfactants might be a risk factor for skin aging.

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Bimolecular fluorescence complementation (BiFC) assay makes it possible to visualize protein-protein interactions in living cells. In this assay, Venus, a bright-yellow variant of green fluorescent protein, is known to produce fluorescent backgrounds due to non-specific interactions. In this study we found that the V150A mutation increased by 8.6-fold the signal-to-noise ratio in the BiFC assay of bFos-bJun interaction.

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The Drosophila transglutaminase gene (CG7356) encodes two transglutaminases, dTG-A and dTG-B. To understand the roles of dTG-B during the development of the fly, we examined phenotypes induced through ectopic expression of dTG-B. Overexpression of dTG-B induced rough eye and extra wing crossvein phenotypes. These phenotypes were similar to those observed in the case of targeted overexpression of dTG-A.

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Pyridylamino derivatization is suitable for the microanalysis of sugars, but there is a problem in that by-products of the labeling reaction and fluorescent substances from samples occasionally interfere with the detection of pyridylamino sugars. Especially, interference by them is serious in monosaccharide analysis. I have developed a convenient purification method for pyridylamino monosaccharides by the use of a spin column with boronate-conjugated resin.

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In higher plants, autophagy-related genes (ATGs) appear to play important roles in development, senescence, and starvation responses. Hormone signals underlying starvation-induced gene expression are involved in the expression of ATGs. An effect of starvation stress on the expression of ATGs and ethylene-related genes in young seedlings of soybean (Glycine max [L.] Merr. cv. Fukuyutaka) was analyzed. Reverse transcription-polymerase chain reaction (RT-PCR) showed that the expression levels of GmATG8i and GmATG4 increase in a starvation medium, but at a null or marginal level in a sucrose/nitrate-rich medium. The expression of GmACC synthase and GmERF are also upregulated in the starvation medium. In addition, immunoblot revealed that ethylene insensitive 3 (Ein3), an ethylene-induced transcription factor are accumulated in seedlings subjected to severe starvation stress. These results indicate that starvation stress stimulates the expression of GmATG8i and ethylene signal-related genes. Since the ethylene signal is involved in senescence and various environmental stresses, it is possible that starvation stress-induced autophagy is partly mediated by the ethylene signaling.

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The purpose of this study was to determine the effect of isothiocyanates (ITCs) in delaying the progression of the murine immunodeficiency virus to murine AIDS, resulting in increased life span. Furthermore, we investigated the role of ITCs in modulating immune dysfunction caused by LP-BM5 retrovirus infection. Among the tested ITCs, oral administration of sulforaphane (SUL), benzyl isothiocyante (BITC), and phenethyl isothiocyanate (PEITC) showed the inhibition of premature death caused by LP-BM5 retrovirus infection, while indolo[3,2-b] carbazole (ICZ) and indole-3-carbinol (I3C) did not delay the progress of the LP-BM5 retrovirus to murine AIDS. Inhibition of premature death by BITC, PEITC, and SUL could be explained by restoration of the immune system and down regulation of free radicals. Dysfunction of T and B cell mitogenesis caused by retrovirus infection in primary cultured splenocytes has been partially recovered with administration of BITC, PEITC, and SUL. There was a shift from imbalanced cytokine production (increased Th2 and decreased Th1 cell cytokine production) into balanced Th1/Th2 cell secretion of cytokines under administration of these ITCs during the development of murine AIDS. Hepatic vitamin E level was significantly restored by administration of these ITCs, in accordance with reduced hepatic lipid peroxidation levels. This study suggests that certain types of ITCs have beneficial effects in preventing premature death during progression to murine AIDS by restoration of immune dysfunction and removal of excessive free radicals, implying that selective usage of ITCs would be helpful in retarding the progression from HIV infection to AIDS.

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The color of soy sauce is considered to be mainly attributable to melanoidins formed by the Maillard reaction. However, the chemical structure of melanoidins cannot be clarified, because melanoidins are high-molecular-weight heterogeneous polymers. We isolated a low-molecular-weight pigment from soy sauce and identified 2,4-dihydroxy-2,5-dimethyl-3(2H)-thiophenone as this pigment formed by the Maillard reaction, although its contribution to the total color of soy sauce was very low.

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Tropomyosin had been identified as a major allergen in shrimp. The digestion and absorption of tropomyosin (Pen j 1) from kuruma prawn were investigated by ex vivo, in vitro, and in vivo techniques in order to elucidate the relationship between the allergenicity of the allergen and its gastrointestinal behavior. Pen j 1 transported the Caco-2 monolayer in a dose-dependent manner, and also enhanced the permeability of lucifer yellow, a marker of paracellular transportation, at high concentrations of the allergen. Studies with everted sacs revealed that Pen j 1 was rapidly degraded to small peptides (MW<3.5 kDa) and amino acids by intestinal proteases and absorbed from enterocytes. Furthermore, Pen j 1 orally administered to rats tended to remain in the stomach rather than in the small intestine, after which the allergen moved to the epithelial cells. These observations suggest that Pen j 1 may be absorbed via the gastric mucosa prior to its digestion in the intestines.

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Resveratrol is a strong candidate for explaining an irreversible correlation between red wine consumption and coronary heart disease. The present study examined the effect of ε-viniferin, a dehydrodimer of resveratrol, on vascular smooth muscle cells (VSMCs), because ε-viniferin functions are poorly understood in spite of its comparable content to resveratrol in red wines and grapes. Both ε-viniferin and resveratrol inhibited platelet-derived growth factor-induced cell proliferation, migration, and reactive oxygen species (ROS) production, in addition to inducing nitric oxide generation. ε-Viniferin was more effective than resveratrol in these effects, except for inhibiting ROS production. The compounds also increased the expression of the antioxidant enzyme, hemeoxygenase-1, via transcription factor Nrf2. The phosphatidylinositol 3-kinase-Akt pathway was implicated in resveratrol-dependent nuclear Nrf2 accumulation, whereas extracellular signal-regulated kinase and p38 were involved in ε-viniferin-induced Nrf2 accumulation. These data suggest that ε-viniferin may function more effectively than resveratrol in different mechanisms and cooperatively with resveratrol in preventing atherosclerosis.

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To clarify the key compounds that account for the umami taste of soy sauce, a typical Japanese soy sauce, Koikuchi Shoyu, was separated by preparative chromatography, and the umami enhancing fractions were screened on the basis of an umami intensity of a 6.0 mM monosodium L-glutamate (MSG) solution. Liquid chromatography-time of flight mass spectrometry (LC-TOFMS), 1D/2D nuclear magnetic resonance spectroscopy (NMR) studies of the umami enhancing fractions led to the identification of N-(1-deoxy-D-fructos-1-yl)pyroglutamic acid (Fru-pGlu), N-(1-deoxy-D-fructos-1-yl)valine (Fru-Val), N-(1-deoxy-D-fructos-1-yl)methionine (Fru-Met), pyroglutamylglutamine (pGlu-Gln), and pyroglutamylglycine (pGlu-Gly). Although all the compounds identified were at sub-threshold concentrations in the soy sauce, a taste reconstitution experiment revealed that they contributed part of the umami taste of the soy sauce.

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The effects of two types of chondroitin sulphate (CS), CS-A and CS-C, their oligosaccharides (oligo-CSs), and disaccharides (Di-CSs) on toll-like receptor (TLR)-mediated secretion of interleukin (IL)-6 were compared using macrophage-like cell line J774.1. IL-6 secretion in the J774.1 cells was markedly increased by Pam3CS4, LPS, and CpG, the ligands to TLR1/2, 4, and 9 respectively. Among these three ligands, CpG-induced IL-6 was most clearly suppressed by CSs and their digests. Suppression of IL-6 secretion by smaller sized CS-A was stronger than that by intact CS-A, whereas no such size-dependent suppression was apparent for CS-C. Di-4S, the disaccharide unit of the CS-A digest, also showed much stronger suppression than Di-6S, the disaccharide unit of the CS-C digest, and the non-sulfated disaccharide unit, Di-0S. The suppressing activity of oligo-CSs, particularly Di-CSs, against TLR-mediated inflammation was dependent on the CS structure, including the sulfation site.

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A rapid method for predicting the buckwheat flour ratio of dried buckwheat noodles was developed by using the fluorescence fingerprint and partial least squares regression. Fitting the calibration model to validation datasets showed R²=0.78 and SEP=12.4%. The model was refined for a better fit by deleting several samples containing additional ingredients. The best fit was finally obtained (R²=0.84 and SEP=10.4%) by deleting the samples containing vinegar, green tea, seaweed, polysaccharide thickener, and yam. This result demonstrates that a calibration model with high accuracy could be constructed based on samples similar in material composition. The developed methodology requires no complex preprocessing, enables rapid measurement with a small sample amount, and would thus be suitable for practical application to the food industry.

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The effects of betaine supplementation on D-galactosamine-induced liver injury were examined in terms of hepatic and serum enzyme activities and of the levels of glutathione and betaine-derived intermediates. The rats induced with liver injury showed marked increases in serum enzyme activity, but those receiving dietary supplementation of 1% betaine showed enzyme activity levels similar to a control group without liver injury. Administration of betaine also increased both hepatic and serum glutathione levels, even following D-galactosamine injection. The activity of glutathione-related enzymes was markedly decreased following injection of D-galactosamine, but remained comparable to that of the control group in rats receiving 1% betaine. The concentrations of hepatic S-adenosyl methionine and cysteine showed similar trends to that observed for hepatic glutathione levels. These results indicate that 1% betaine has a hepatoprotective effect by increasing hepatic and serum glutathione levels along with glutathione-related enzyme activities in rats.

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Lycopene dispersed in aqueous solutions with different dissolved oxygen contents was photo-irradiated by using a xenon weather meter, and the contents of lycopene and dissolved oxygen were measured. Both the degradation of lycopene and the consumption of dissolved oxygen followed a first-order kinetics model. There was a proportional relationship between the degradation content of lycopene and the consumption of dissolved oxygen. These results indicate that dissolved oxygen would also be involved in the photolysis of lycopene.

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A microbial consortium that reductively dechlorinates trichloroethene, cis-1,2-dichloroethene (cis-DCE), and vinyl chloride (VC) to ethene with methanogenesis was enriched from chloroethene-contaminated soil from Japan. Dechlorination activity was maintained for over 4 years. Using quantitative polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analysis targeting the “Dehalococcoides” 16S rRNA gene, four strains were detected. Their growth and dechlorination activities were classified into two types: one that grows by converting cis-DCE to ethene and the other that grows by converting cis-DCE to VC. Then, the vcrA and bvcA genes encoding cis-DCE/VC reductive dehalogenases were detected. Inhibitors of methanogenesis (2-bromoethanesulfonate) and sulfidogenesis (molybdate) led to accumulation of cis-DCE and of VC respectively. These results suggest that methanogens and sulfate-reducing bacteria can play a significant role in dechlorination by “Dehalococcoides.”

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Genes encoding salt-tolerant and thermostable glutaminases were isolated from Cryptococcus species. The glutaminase gene, CngahA, from C. nodaensis NISL-3771 was 2,052 bp in length and encoded a 684-amino acid protein. The gene, CagahA, from C. albidus ATCC20293 was 2,100 bp in length and encoded a 700-amino acid protein. These glutaminases showed 44% identity. By searches on public databases, we found that these glutaminases are not similar to any other characterized glutaminases, but are similar to certain hypothetical proteins. On searching the conserved domain with the basic local alignment search tool (BLAST), it was found that they have the amidase domain and are members of the amidase signature superfamily. They were expressed in Saccharomyces cerevisiae, and their activity was detected on the cell surface. This study revealed that they are a new type of glutaminase with the amidase signature sequence, and that they form a new glutaminase family.

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Mannosylerythritol lipids (MELs) are glycolipid biosurfactants excreted by fungal strains. They show not only excellent surface-active properties but also versatile biochemical actions. Ustilago scitaminea NBRC 32730 has been reported mainly to produce a mono-acetylated and di-acylated MEL, MEL-B, from sucrose as sole carbon source. In order to make biosurfactant production more efficient, we focused our attention on the use of sugarcane juice, one of the most economical resources. The fungal strain produced MEL-B at the yield of 12.7 g/L from only sugarcane juice containing 22.4% w/w sugars. Supplementation with organic (yeast extract, peptone, and urea) and inorganic (sodium nitrate and ammonium nitrate) nitrogen sources markedly enhanced the production yield. Of the nitrogen sources, urea gave the best yield. Under optimum conditions, the strain produced 25.1 g/L of MEL-B from the juice (19.3% sugars) supplemented with 1 g/L of urea in a jar fermenter at 25 °C over 7 d. The critical micelle concentration (CMC) and the surface-tension at the CMC for the present MEL-B were 3.7×10⁻⁶ M and 25.2 mN/m respectively. On water-penetration scan, the biosurfactant efficiently formed the lamella phase (L_α) and myelins over a wide range of concentrations, indicating excellent surface-active and self-assembling properties. More significantly, the biosurfactant showed a ceramide-like skin-care property in a three-dimensional cultured human skin model. Thus, sugarcane juice is likely to be effective in glycolipid production by U. scitaminea NBRC 32730, and should facilitate the application of MELs.

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