Differences in susceptibility of cyanobacteria species to lytic volatile organic compounds and influence on seasonal succession.

Cyanobacteria produce numerous volatile organic compounds (VOCs) that show a lytic activity against other cyanobacteria. We found the lytic phenomenon under natural conditions and during densification experiments, and also observed the species change of the cyanobacteria during the lysis processes, in which Microcystis finally became dominant. The species change of the cyanobacteria was strongly suggested to depend on the susceptibility of the cyanobacteria toward the VOCs.

[Analysis of Dieldrin and DTTB in Textiles].

Standard analytical methods for the detection of dieldrin and 4,6-dichloro-7-(2,4,5-trichlorophenoxy)-2-trifluoromethylbenzimidazole (DTTB) in textiles, which are regulated by Japanese law ("Act on the Control of Household Products Containing Harmful Substances"), have been in place for more than 30 years. In this study, we developed an improved analytical method, based on GC-MS, that uses safe reagents and can simultaneously detect dieldrin and DTTB analytes. In the standard (existing) analytical method, dimethyl sulfate, which is a potential carcinogen, is used to derivatize DTTB.

Analytical Technique Optimization on the Detection of β-cyclocitral in Species.

β-Cyclocitral, specifically produced by , is one of the volatile organic compounds (VOCs) derived from cyanobacteria and has a lytic activity. It is postulated that β-cyclocitral is a key compound for regulating the occurrence of cyanobacteria and related microorganisms in an aquatic environment. β-Cyclocitral is sensitively detected when a high density of the cells is achieved from late summer to autumn.

Complete Genome Sequence of a Microcystin-Degrading Bacterium, Sphingosinicella microcystinivorans Strain B-9.

Sphingosinicella microcystinivorans strain B-9 has the ability to degrade cyanobacterial hepatotoxic cyclic peptides, microcystins, and nodularins. This is the first report of the complete genome sequence of the microcystin-degrading bacterium.

Microbial Degradation of Amino Acid-Containing Compounds Using the Microcystin-Degrading Bacterial Strain B-9.

Strain B-9, which has a 99% similarity to strain Y2, is a Gram-negative bacterium with potential for use in the degradation of microcystin-related compounds and nodularin. We attempted to extend the application area of strain B-9 and applied it to mycotoxins produced by fungi. Among the tested mycotoxins, only ochratoxin A was completely hydrolyzed to provide the constituents ochratoxin α and l-phenylalanine, and levels of fumonisin B1 gradually decreased after 96 h.

Characteristic oxidation behavior of β-cyclocitral from the cyanobacterium Microcystis.

The cyanobacterium Microcystis produces volatile organic compounds such as β-cyclocitral and 3-methyl-1-butanol. The lysis of cyanobacteria involving the blue color formation has been occasionally observed in a natural environment. In this study, we focused on the oxidation behavior of β-cyclocitral that contributed to the blue color formation in a natural environment and compared β-cyclocitral with a structurally related compound concerning its oxidation, acidification, and lytic behavior.

Cyanobacterial blue color formation during lysis under natural conditions.

Cyanobacteria produce numerous volatile organic compounds (VOCs), such as β-cyclocitral, geosmin, and 2-methylisoborneol, which show lytic activity against cyanobacteria. Among these compounds, only β-cyclocitral causes a characteristic color change from green to blue (blue color formation) in the culture broth during the lysis process. In August 2008 and September 2010, the lysis of cyanobacteria involving blue color formation was observed at Lake Tsukui in northern Kanagawa Prefecture, Japan.

Microbial degradation of linear peptides by strain B-9 of Sphingosinicella and its application in peptide quantification using liquid chromatography-mass spectrometry.

The bacterial strain Sphingosinicella sp. B-9 was originally discovered to have the ability to degrade cyanobacterial cyclic peptides (microcystins), and has three hydrolytic enzymes (MlrA, MlrB, and MlrC). The purpose of this study was to examine in detail the degradation of glucagon/vasoactive intestinal polypeptide (VIP) family peptides by B-9, and to investigate the substrate specificity of B-9 proteases and the possibility of using a B-9 protease as a novel protease for peptide quantification by using a surrogate peptide and mass spectrometry (MS).

Safety prediction of topically exposed biocides using permeability coefficients and the desquamation rate at the stratum corneum.

Advances in the synthesis and utilization of new chemical compounds have led to improvements in our daily lives. However, new chemicals may be both beneficial and toxic. Thus, exposure to these new compounds should be restricted in an attempt to limit their potential toxicities.

Volatile organic compounds derived from 2-keto-acid decarboxylase in Microcystis aeruginosa.

Volatile organic compounds (VOCs), 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol, were detected together with β-cyclocitral from the cyanobacterium Microcystis aeruginosa NIES-843. These alcohols were optimally produced after 35 d of culture, during which nitrate nitrogen in the cultured broth became exhausted. Additionally, these alcohols were definitely produced using the 2-keto-acid decarboxylase (MaKDC) in Microcystis strains.

Microbial degradation of physiologically active peptides by strain B-9.

The reaction of some physiologically active peptides with bacterial strain B-9 has been investigated. Bradykinin, β-endorphin, and [Leu(5)]enkephalin were quickly degraded, with half-lives of <5 min. Somatostatin, substance P, and angiotensin I were degraded relatively smoothly, with half-lives of 10 min to 1 h, whereas oxytocin and insulin were slowly degraded, with half-lives of 1 and 4 days, respectively.

Analytical aspects of cyanobacterial volatile organic compounds for investigation of their production behavior.

In order to fully understand the role of volatile organic compounds (VOCs) under natural conditions, an adaptable analytical method was developed as the first step. beta-Ionone, beta-cyclocitral, 2-methyl-1-butanol and 3-methyl-1-butanol were simultaneously analyzed in addition to geosmin and 2-MIB using GC/MS with SPME. The slight modification of a known method allowed the simultaneous detection and quantification of these VOCs.

Leptin stimulates fibroblast growth factor 23 expression in bone and suppresses renal 1alpha,25-dihydroxyvitamin D3 synthesis in leptin-deficient mice.

Leptin is the LEP (ob) gene product secreted by adipocytes. We previously reported that leptin decreases renal expression of the 25-hydroxyvitamin D(3) 1alpha-hydroxylase (CYP27B1) gene through the leptin receptor (ObRb) by indirectly acting on the proximal tubules. This study focused on bone-derived fibroblast growth factor 23 (FGF-23) as a mediator of the influence of leptin on renal 1alpha-hydroxylase mRNA expression in leptin-deficient ob/ob mice.

Blue color formation of cyanobacteria with beta-cyclocitral.

Volatile compounds, such as beta-cyclocitral, geosmin, and 2-methylisoborneol, from cyanobacteria showed a lytic activity against cyanobacteria. Particularly, beta-cyclocitral caused an interesting color change in the culture broth from green to blue during the lysis process. In the present study, the lytic behavior of various cyanobacteria with beta-cyclocitral was investigated, and a mechanism for the blue color formation was developed.

Ceramide biosynthesis in keratinocyte and its role in skin function.

The enucleate layer of the epidermis, i.e. the stratum corneum, is responsible for certain critical protective functions, such as epidermal permeability barrier function.

Evaluation of synthetic sphingolipid analogs as ligands for peroxisome proliferator-activated receptors.

In this Letter, we assessed newly synthesized sphingolipid analogs as ligands for peroxisome proliferator-activated receptor (PPAR)alpha, PPARbeta or PPARgamma, using a dual-luciferase reporter system. We tested 640 sphingolipid analogs for ligand activity. As a result, seven types: A9, B9, C9, C50, F66, G66 and H66, were found to show agonistic activities for PPARs.

Microbial degradation of cyclic peptides produced by bacteria.

Bacterial strain, B-9, isolated from Lake Tsukui, Japan, and characterized as genus Sphingosinicella sp., possesses hydrolytic enzymes capable of degrading various toxic and non-toxic cyanobacterial cyclic peptides, such as microcystins, nodularin, microviridin, microcyclamide and aeruginopeptin. In this study, the degradation activities of the cell extract of B-9 against bacterial cyclic peptides, bacitracin, colistin, polymyxin, mikamycin, thiopeptin and WAP-8294A2, were investigated and the degradation products were analyzed using HPLC and liquid chromatography/ion trap tandem mass spectrometry (LC/ITMS).

Further investigation of microbial degradation of microcystin using the advanced Marfey method.

It is known that microcystin (MC) is subject to microbial degradation to provide three types of products, linearized MCLR (Adda-Glu-Mdha-Ala-Leu-MeAsp-Arg), tetrapeptide Adda-Glu-Mdha-Ala, and Adda. They can be readily detected by the usual HPLC, because they commonly have an Adda moiety with a diene and an absorption maximum at 238 nm as the chromophore. However, no other degradation products without such a chromophore have been isolated to date.

Role of ceramide kinase in peroxisome proliferator-activated receptor beta-induced cell survival of mouse keratinocytes.

Ceramide (Cer) is known to be a lipid mediator in apoptosis and to have an important role in cell fate, via control of intracellular Cer levels. Recently, ceramide kinase (CerK) was identified as an enzyme that converts Cer to ceramide 1-phosphate (C1P). We examined potential functions of CerK in the regulation of keratinocyte survival, and the possible involvement of peroxisome proliferator-activated receptor beta (PPARbeta).

Lysis of cyanobacteria with volatile organic compounds.

One of bacteria collected from Lake Sagami, Japan, Brevibacillus sp., was found to have a lytic activity of cyanobacteria, but did not produce active compounds. Instead, the co-culturing of Microcystis with the Brevibacillus sp.

Microbial degradation of cyanobacterial cyclic peptides.

Bacterial strain B-9 possesses hydrolytic enzymes capable of degrading microcystins (MCs) and nodularin that are toxic cyclic peptides produced by cyanobacteria. In the present study, the degradation activities of the cell extract of B-9 against non-toxic cyanobacterial cyclic peptides other than the MCs and nodularin were investigated, and the degradation products were analyzed by liquid chromatography/ion trap tandem mass spectrometry (LC/ITMS). It was confirmed that B-9 could also degrade these cyanobacterial cyclic peptides by hydrolysis of their peptide bonds.

Dietary glucosylceramide improves skin barrier function in hairless mice.

Background: Sphingolipids are known to play an important role in both water retention and epidermal permeability barrier function in mammalian stratum corneum. However, little is known about the effects on epidermal function of orally administered sphingolipids.

Objective: We examined the effect of dietary glucosylceramide (GluCer) on the maintenance and recovery of epidermal barrier function.

Degradation of microcystins using immobilized microorganism isolated in an eutrophic lake.

The final purpose of our series of studies is to establish a biological removal method of cyanobacteria and their toxic products using immobilized microorganisms that can lyse cyanobacteria and decompose microcystins. To establish the biological removal method in non-point areas and water purification plants, as the first step, we explored bacteria active against the cyanobacterial hepatotoxin microcystin in the present study. Eleven active bacteria were isolated from samples taken from Lakes Tsukui and Sagami, Japan.

Apoptosis occurs via the ceramide recycling pathway in human HaCaT keratinocytes.

Keratinocytes contain abundant ceramides compared to other cells. However, studies on these cells have mainly focused on the barrier function of ceramide, while their other roles, such as those in apoptosis or cell cycle arrest, have not been well addressed. In this study, we investigated the apoptosis-inducing effect of exogenously added cell-permeable ceramides in HaCaT keratinocytes.