Actinorhodin, an antibiotic produced by Streptomyces coelicolor, is exported from the cell by the ActA efflux pump. actA is divergently transcribed from actR, which encodes a TetR-like transcriptional repressor. We showed previously that ActR represses transcription by binding to an operator fro...

An oxygenated derivative of dihydrokalafungin (DHK) was isolated from a deletion mutant of the actVA-ORF4 gene involved in the biosynthesis of a dimeric benzoisochromanequinone (BIQ) antibiotic, actinorhodin (ACT), in Streptomyces coelicolor A3(2). Spectroscopic analysis elucidated its structure...

Colors from natural sources are gaining popularity because synthetic colors are carcinogenic. Natural colors are obtained from plants or microorganisms. Pigments produced by microorganisms have advantages over plant pigments, due to their ease of use and reliability. In the present study, a blue...

In the present work, a new method of purification for actinorhodin was developed using an expanded bed chromatography technique in which antibiotic capture, feedstock clarification, centrifugation, dialysis and concentration are done in one step. The cation-exchanger (P-11) resulted in 26% adsor...

Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomyce...

Streptomyces is a genus of Gram-positive bacteria that grow in various environments, and its shape resembles filamentous fungi. The most interesting property of Streptomyces is the ability to produce bioactive secondary metabolites, such as antifungals, antivirals, antitumorals, and especially a...

The chloroform extract of the heartwood of Pterocarpus santalinus yielded a mixture of red pigments which could be separated by polyamide column chromatography into two major compounds, santalin-A and santalin-B. Both gave the same permethyl ether, C38H36O10 which had 8 methoxyls and formed a nu...

A novel yellow pigment named santalin Y, related to red pigment santalin A was isolated from Pterocarpus santalinus. Its structure was determined by various spectral data including X-ray analysis. Biogenetic relationships for these compounds were also discussed.

Santalin, a pigment extracted from red sandalwood strongly surface complex to TiO2, sensitizing nano-porous film of TiO2 to the visible spectrum. Because of the stability of such films, dye-sensitized solid state photovoltaic cells of sandwich structure (nano-porous n-TiO2/santalin/p-type semico...

The heartwood of Pterocarpus santalinus contains two major red pigments, santalin-A and santalin-B which are partial methyl ethers of the same polyphenol (santalin). For locating the position of the methoxyl groups, alkali fission and permanganate oxidation of the mixed ethyl methyl ethers are t...

The performance of natural dyes in dye-sensitized solar cells is usually worse than that of purpose-built organic dyes. Here, we set out to investigate the underlying origins. Two natural dyes, carminic acid and santalin, were selected as potential sensitizers for dye-sensitized solar cells. The...

Excessive melanin production leads to hyperpigmentation disorders which results in distressing aesthetic values. Though there are some synthetic depigmentation agents available it has been reported to possess cytotoxic and mutagenic effects. Hence there is a need for the development of safe and ...

Biosynthesis of dipeptide antibiotic bacilysin by a partially purified enzyme prepared from Bacillus subtilis PY79 was studied. Cell material was desintegrated by treatment with lysozyme and sonication and the extract was subjected to ammonium sulfate fractionation. Bacilysin-synthesizing enzyme...

Bacilysin is a dipeptide antibiotic composed of l-alanine and l-anticapsin. We recently reported partial purification and characterization of the bacilysin synthetase. In the present study, l-anticapsin in the in vitro reaction mixture was replaced by furfurylamine, norephedrine, glycine, and be...

In Bacillus subtilis, two extracellular signaling peptides, ComX pheromone and CSF (competence and sporulation factor), stimulate the development of genetic competence and surfaction biosynthesis in response to high cell density (quorum sensing) by regulating the activity of transcription factor...

Transposon mutagenesis was employed to isolate the gene(s) related with the biosynthesis of dipeptide antibiotic in Bacillus subtilis PY79 (a prototrophic derivative of the standard 168 strain). The blocked mutants were phenotypically selected from the transposon library by bioassay and the comp...

Representatives of Bacillus amyloliquefaciens were shown to possess biocontrol activity against fire blight, a serious disease of orchard trees caused by Erwinia amylovora. Genome analysis of B. amyloliquefaciens FZB42 identified gene clusters responsible for synthesis of several polyketide comp...

Bacillus subtilis has the capacity to produce more than two dozen bioactive compounds with an amazing variety of chemical structures. Among them, bacilysin is a non-ribosomally synthesized dipeptide antibiotic consisting of l-alanine residue at the N terminus and a non-proteinogenic amino acid, ...

Aflatoxins produced by some strains of the fungal genus Aspergillus are among the most hazardous mycotoxins for humans and livestock, a reason that has forced to investigate efficient strategies of management of these fungal contaminations. Some bacterial species have been proven capable of degr...

Nosema bombycis is the pathogen of pébrine which brings heavy losses to sericulture every year. As a member of serine proteases, subtilisin-like protease (SLP) is related to the pathogenicity in fungi. In this study, we characterized a novel 63.8 kDa subtilisin-like protease NbSLP2 with a predi...