Use of claydite-immobilized oil-oxidizing microbial cells for purification of water from oil

Oil-oxidizing bacteria were isolated from oil-polluted soil and water samples and identified as Acinetobacter calcoaceticus K-4, Nocardia vaceinii K-8, Rhodococcus erythropolis EK-1, and Mycobacterium sp. K-2. It was found that immobilization of the bacteria on an expanded clay aggregate accelerated their growth and consumption of hydrocarbon substrates. It was also found that water polluted with 100 mg/l oil could be purified with Rhodococcus erythropolis EK-1 and Nocardia vaceinii K-8 cells immobilized in this way. The dependence of the degree of water purification on its flow rate, aeration, and availability of nitrogen and phosphorus sources was determined. The efficiency of water purification from oil by immobilized Rhodococcus erythropolis EK-1 cells at high flow rates (of up to 0.68 l/h), low aeration (of 0.1 l/l per min) and an intermittent supply of 0.01% diammonium phosphate reached 99.5-99.8%.     

Karyotype of Mesembryanthemum crystallinum (Aizoaceae) studied by chromosome banding,FISH with rDNA probes and immunofluorescence detection of DNA methylation

The karyotype of the common ice plant Mesembryanthemum crystallinum L. (Aizoaceae) was studied using Chromomycin A₃ (CMA)/4′,6-diamidino-2-phenylindole (DAPI) staining, fluorescence in situ hybridization with 5S and 18S–5.8S–25S rDNA probes, DAPI/C-banding and immunodetection of 5-methylcytosine. A single bright CMA-band was revealed on the satellite chromosome, whose location was coincided with a position of a site of 18S–5.8S–25S rRNA genes. A site of 5S rRNA genes was observed on one of the other chromosomes. Relatively large DAPI/C-bands were mainly localized in the pericentromeric regions of the chromosomes. DAPI/C-banding patterns allowed us to identify all the chromosomes in the karyotype of M. crystallinum. The methylation of euchromatic chromosome regions was weaker as compared with heterochromatic DAPI/C-bands, which were hypermethylated. The obtained results may provide opportunities for investigating, at the chromosomal level, the genomic changes occurring in M. crystallinum either under salinization or under the action of other stress factors.     

Ion channels in small cells and subcellular structures can be studied with a smart patch-clamp system

We have developed a scanning patch-clamp technique that facilitates single-channel recording from small cells and submicron cellular structures that are inaccessible by conventional methods. The scanning patch-clamp technique combines scanning ion conductance microscopy and patch-clamp recording through a single glass nanopipette probe. In this method the nanopipette is first scanned over a cell surface, using current feedback, to obtain a high-resolution topographic image. This same pipette is then used to make the patch-clamp recording. Because image information is obtained via the patch electrode it can be used to position the pipette onto a cell with nanometer precision. The utility of this technique is demonstrated by obtaining ion channel recordings from the top of epithelial microvilli and openings of cardiomyocyte T-tubules. Furthermore, for the first time we have demonstrated that it is possible to record ion channels from very small cells, such as sperm cells, under physiological conditions as well as record from cellular microstructures such as submicron neuronal processes.     

The absence of the CpNpG methylation at the 5′-terminal region of the human calcitonin gene in norm and leukemias

The inner cytosine methylation was analyzed in the CCWGG sequences of the 5′-terminal region of the human calcitonin gene from peripheral blood and bone marrow cells in various forms of leukemia. Since these sequences remain nonmethylated both in the norm and in various leukemia forms, the CpG dinucleotide hypermethylation of the 5′-end of the human calcitonin gene, characteristic for the development of leukemias, does not spread to adjacent CpNpG sequences.     

The Effect of the Gene Encoding EcoRII DNA Methyltransferase on the Phenotype of Transgenic Tumor Cell Lines of Nicotiana tabacumand the Methylation Level of CpNpG Sequences in Their Genome

Several tumor cell lines were obtained by transforming Nicotiana tabacumplants with the recombinant Ti plasmid comprising the gene encoding EcoRII DNA methyltransferase (M·EcoRII) and subjected to analysis. The transformed lines differed in their morphology, growth dependence on hormones, and nopaline-synthesizing capacity. Southern blot-hybridization showed that the M·EcoRII gene was present in the cells of all transformed lines. However, genome analysis using polymerase chain reaction with the oligonucleotide primers recognizing 5"-ends of the M·EcoRII gene did not exhibit the full-length copies of the gene. Lower methylation of CpNpG sequences characteristic of all transformed cells could result from the disturbance of one of several plant DNA methyltransferase genes following its homologous recombination with the M·EcoRII gene.     

Effect of hypermethylation of CCWGG sequences in DNA of Mesembryanthemum crystallinum plants on their adaptation to salt stress

Under salt stress conditions, the level of CpNpG-methylation (N is any nucleoside) of the nuclear genome of the facultative halophyte Mesembryanthemum crystallinum in the CCWGG sequences (W = A or T) increases two-fold and is coupled with hypermethylation of satellite DNA on switching-over of C3-photosynthesis to the crassulacean acid metabolism (CAM) pathway of carbon dioxide assimilation. The methylation pattern of the CCWGG sequences is not changed in both the 5'-promoter region of the gene of phosphoenolpyruvate carboxylase, the key enzyme of C4-photosynthesis and CAM, and in the nuclear ribosomal DNA. Thus, a specific CpNpG-hypermethylation of satellite DNA has been found under conditions of expression of a new metabolic program. The functional role of the CpNpG-hypermethylation of satellite DNA is probably associated with formation of a specialized chromatin structure simultaneously regulating expression of a large number of genes in the cells of M. crystallinum plants on their adaptation to salt stress and switching-over to CAM metabolism.     

Ecologic and epidemiologic features of the circulation of streptococcus group B at a maternity clinic

In a maternity clinic the circulation of group B streptococci among the newborns, their mothers and the personnel was established during the period of 1982-1985. Group B streptococci were detected at different biotypes of newborns (the pharynx, the imbilical stump, external suditory meatus, nasal and oral mucosa, eyes and feces), their mothers (the vagina, the perianal area, breast milk, the pharynx, urine, the umbilical cord, amniotic fluid) and in the pharynx of the personnel. In this maternity clinic 15 combinations of type antigens were detected, two combinations (1a/c and 1 b/c) prevailing among them. These results confirmed earlier data concerning two possible ways of transferring infection to newborn infants: vertical, i.e. from the mother to the child during parturition, and nosocomial, i.e. from contaminated newborns or members of the personnel.     

DNA methyltransferases for detection of the level of methylation of cytosine in the DNA CCWGG sequence

An assay for the cytosine methylation level in the eukaryotic DNA CCWGG sequence is proposed. The method is based on the ability of DNA methylase BstNI to methylate DNA containing in a CCWGG site a nonmodified or 5-methylated cytosine to yield N4-methyl- or N4,5'-dimethylcytosine, respectively.