<Emphasis Type="Italic">Bacillus subtilis</Emphasis> and Phenotypically Similar Strains Producing Hexaene Antibiotics

We studied metabolites synthesized by Bacillus subtilis strains, including the type strain of B. atrophaeus and phenotypically similar cultures. These metabolites were represented by polyene antibiotics with conjugated double bonds. Hexaenes from the strains under study inhibited the growth of phytopathogenic fungi Fusarium culmorum, F. sporotrichiella, F. oxysporum, Botrytis sorokiniana, Alternaria tenui, and Phytophthora infestans. The degree of growth inhibition depended on the test fungus.     

Bacillus subtilis and phenotypically similar strains producing hexaene antibiotics

We studied metabolites synthesized by Bacillus subtilis strains, including the type strain of B. atrophaeus and phenotypically similar cultures. These metabolites were presented by polyene antibiotics with conjugated double bonds. Hexaenes from study strains inhibited the growth of phytopathogenic fungi Fusarium culmorum, F. sporotrichiella, F. oxysporum, Botrytis sorokiniana, Alternaria tenuis, and Phytophtora infestans. The degree of growth inhibition depended on the test fungus.     

Cervical carcinoma progression-associated genetic alterations on chromosome 6

To identify the loci associated with progression of cervical carcinoma, chromosome 6 regions were tested for loss of heterozygosity. Detailed analysis with 28 microsatellite markers revealed a high frequency of allelic deletions for several loci of the short (6p25, 6p22, 6p21.3) and long (6q14, 6q16-21, 6q23-24, 6q25, 6q27) arms of chromosome 6. Examination of 37 microdissected carcinoma and 22 cervical dysplasia specimens revealed allelic deletions from the HLA class I-III genes (6p22-21.3) and subtelomeric locus 6p25 were found in more than 40% dysplasia specimens. With multiple microdissection of cryosections, genetic heterogeneity of squamous cervical carcinoma was analyzed, and clonal and subclonal allelic deletions from chromosome 6 were identified. Half of the tumors had clonal allelic deletion of D6S273 (6p21.3), which is in a Ly6G6D (MEGT1) intron in the HLA class III gene locus. The frequency of allelic deletions from the chromosome 6 long arm was no more than 20% in dysplasias. Allelic deletions from two loci, 6q14 and 6q16-21, were for the first time associated with invasion and metastasis in cervical carcinoma.     

Study of chitin-glucan complexes from the soil micromycete <Emphasis Type="Italic">Cephaliophora tropica</Emphasis> D3

We studied chitin-glucan complexes from the soil micromycete Cephaliophora tropica D3. The yield and purity of chitin-glucan complexes depended on the medium used for micromycete culturing and the method of mycelium disintegration. Disintegration with liquid nitrogen allowed us to obtain preparations of chitin-glucan complexes with a low content of proteins and a high yield of chitosan (per dry fungal biomass unit weight).     

Studying factors involved in biogenesis of <Emphasis Type="Italic">Lysobacter</Emphasis> sp. XL1 outer membrane vesicles

The Gram-negative bacterium Lysobacter sp. XL1 produces outer membrane vesicles that are heterogeneous in size, density, and protein composition. One of the subpopulations is secretory vesicles for lytic protease L5 of Lysobacter sp. XL1 (Kudryakova et al. (2015) FEMS Microbiol. Lett., 362, fnv137). Protein L5 was assumed to influence biogenesis of these secretory vesicles that contain it. Using a Pseudomonas fluorescens Q2-87/B expression system, it was shown that the recombinant L5 protein may act as a factor of vesicle biogenesis. This points to a possible involvement of L5 protein in Lysobacter sp. XL1 vesicle biogenesis. Furthermore, it was established that the main phospholipid of Lysobacter sp. XL1 vesicles is cardiolipin, and vesicles are formed predominantly of outer membrane regions enriched with this phospholipid. This indicates that cardiolipin participates in biogenesis of all vesicle subpopulations in Lysobacter sp. XL1.     

Recombinant xylanase from Streptomyces coelicolor Ac-738: characterization and the effect on xylan-containing products

A xylanase gene was isolated from the genomic DNA of Streptomyces coelicolor Ac-738. The 723-bp full-length gene encoded a 241-amino acid peptide consisting of a 49-residue putative TAT signal peptide and a glycoside hydrolase family-11 domain. The mature enzyme called XSC738 was expressed in Escherichia coli M15[pREP4]. The electrophoretically homogeneous protein with a specific activity of 167 U/mg for beechwood xylan was purified. The pH optimum of XSC738 was at pH 6; a high activity was retained within a pH range of 4.5–8.5. The enzyme was thermostable at 50–60 °C and retained an activity at pH 3.0–7.0. Xylanase XSC738 was activated by Mn²⁺, Co²⁺ and largely inhibited by Cd²⁺, SDS and EDTA. The products of xylan hydrolysis were mainly xylobiose, xylotriose, xylopentaose and xylohexose. Xylotetraose appeared as a minor product. Processing of such agricultural xylan-containing products as wheat, oats, soy flour and wheat bran by xylanase resulted in an increased content of sugars.     

Succinic acid production from n‐alkanes

A novel process of production of succinic acid (SA) has been developed, which includes the synthesis of alpha‐ketoglutaric acid by a thiamine‐auxotrophic yeast strain Yarrowia lipolytica VKM Y‐2412 from n‐alkanes and subsequent oxidation of the acid by hydrogen peroxide to SA. The concentration of SA in the culture broth and its yield were found to be 38.8 g/L and 82.45% of n‐alkane consumed, respectively. The isolation procedure involved the extraction of the residual alkanes with the mixture of ethyl acetate and hexane, the decomposition of H₂O₂ in the filtrate followed by filtrate bleaching and acidification with a mineral acid; the evaporation of filtrate and the ethanol extraction of SA from lyophilized residue. The purity of the SA isolated from the culture liquid filtrate reached 99.5%.