Upregulation ofE. coli 38kDa proteins induced by glutaraldehyde and formaldehyde

Exposure of the W3110 strain ofEscherichia coli K12 to low concentrations of glutaraldehyde or formaldehyde results in an unusual pattern of protein expression, as determined by high-resolution, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). A decline in total protein synthesis is accompanied by the upregulation of three proteins of approximate molecular weight 38 kDa. In the presence of 0.1 mM glutaraldehyde this response occurs within the first 5 min of incubation, and with 0.1 mM formaldehyde, within the first 30 min of incubation. The 38 kDa proteins continue to be expressed at high levels until cell death. Comparison of our 2-D PAGE patterns withE. coli gene-protein and plasmid indexes indicates that one of the proteins may be the major gene product of thepyrC locus. This pattern of protein synthesis may indicate a novelE. coli stress response.     

Recombinations during DNA cloning

RecA-independent recombinations accompanying the processes of plasmids preparation and cloning into Escherichia coli cells are induced within the short direct and inverted repeats of several types.     

Synthesis, cloning, and expression of artificial genes, coding antigenic determinants of the foot-and-mouth virus substrain A22]

Chemical-enzymatic synthesis and cloning in Escherichia coli of double-stranded DNAs, coding for simple and complex antigenic determinants of foot-and-mouth disease virus (FMDV) strain A22, have been carried out. The simple antigenic determinants are a part of the viral coat protein VP1 (amino acid sequence 131-152 or 131-160) whereas the complex antigenic determinants comprise additionally the amino acid sequence 200-213 of VP1 linked to N-terminus of simple antigenic determinants through a tetrapeptide spacer Pro-Pro-Ser-Pro. Recombinant DNAs containing genes for antigenic determinants of FMDV fused with C-terminus of gene for human tumor necrosis factor (hrTNF) have been constructed. Expression of the hybrid genes and properties of the proteins coded were studied. All recombinant proteins were shown to interact specifically with polyclonal antibodies both against hrTNF and FMDV strain A22. The recombinant proteins produced by bacteria are perspective for study as a vaccine against FMDV.     

Partial blocks in the early steps of the chlorophyll synthesis pathway: A common feature of chlorophyll b-deficient mutants

We have analyzed precursor pools in the chlorophyll (Chi) synthesis pathway for a set of eighteen well studied Chl b -defident mutants in monocotyledonous (barley, maize and wheat) and dicotyledonous plants ( Antirrhinum, Arabidopsis , soybean, tobacco and tomato) that form abnormal thylakoid membrane systems. All of these mutants have a partial block in Chl synthesis and nearly all of them accumulate protoporphyrin IX (Proto), the last porphyrin compound common to both heme and Chl synthesis. The large number of mutants at several genetic loci affecting this critical branchpoint in tetrapyrrole biosynthesis suggests that the Mg-chelatase enzyme, catalyzing the first committed step of Chi biosynthesis, is a multimeric complex composed of the products of some of these genetic loci, and perhaps regulated by others. We hypothesize that these mutants are Chi b -deficient and have reduced amounts of light-harvesting antenna complexes (LHCs.) and develop abnormal thylakoid membranes as a direct result of limited Chl synthesis. The observed bottleneck in Chl synthesis can also explain the light-intensity-dependent and temperature-dependent expression of the mutant phenotype. This hypothesis offers a simple explanation for the wide variety of pbenotypes that have been reported for the many Chl-deficient mutants in the literature. Our findings are also consistent with the notion that Chl b is made from "left over" Chl a molecules and suggest that the Chi b -deficient mutants should be considered more appropriately as leaky Chl-deficient mutants.     

Chromatographic techniques for the isolation and purification of lipoproteins

Various modes of chromatography are available for lipoprotein separation. Gel permeation and affinity chromatography are used for preparative purposes and to separate lipoproteins according to size and apolipoprotein content, respectively. Development of rigid supports for gel permeation has led to large improvements in speed and resolution. Reversed-phase high-performance liquid chromatography (HPLC) of apolipoproteins offers the best performance in terms of speed and resolution of structural variants. Due to its high speed and superior resolving power, the recently developed technique of capillary electrophoresis should emerge as an important method for lipoprotein analysis.     

Morphological variability of geographically distinct populations of the estuarine copepod Acartia Tonsa

Variations in the number of spines on the left and right posterior dorsal and posterior margins of the prosome as well as the length of the prosome of Acartia tonsa from three estuaries, the upper western side of the Chesapeake Bay, Montauk Bay near the eastern end of Long Island Sound and the coast of Peru were determined. The length of the prosome and number of spines in each of the four locations were used as an indication of morphological similarity between the populations.     

DNA sequences of the two homoeologous SLR1 genes of Brassica napus cv Westar

The DNA sequence data reported have been lodged in the Genbank, EMBL and DDBJ databases under the accession numbers Z21609 and Z26914     

Genetic structure of the population of Ashkhabad City of the Turkmen SSR]

Some genetical demographic characteristics of population of Ashkhabad city were studied by direct interviewing of women aged over 18 years. The influence of urbanization on the basic genetical-demographic indices was found, the indices being essentially different from those of rural population studied elsewhere. Analysis of intensity and the structure of marriage migrations showed considerable ethnic subdivision in Ashkhabad population and stability of marriage policy in an every ethnic group. The level and structure of inbreeding as well as positive marriage assortativity are of the same order as in the Turkmen rural population.