Cytoplasmic thyroxine-binding protein: the role of RNA in the interactions between thyroxine receptor and cell nuclei

The presence of 3H-orotic acid in the cytoplasmic receptor fraction isolated in our laboratory, the sensitivity of this fraction to treatment with RNAases accompanied by a shift of the absorption peak of the receptor preparation towards the long-wave region as well as the use of the absorption filter technique point to the existence of ternary thyroxine-thyroxine-binding protein-RNA complex in the cytoplasm. It was found that the cytoplasmic hormone-receptor complex of thyroxine is a genetically active form which can interact with the nuclei and modify the activity of chromatin. The role of RNA in these interactions is discussed.     

Clustering, haplotype diversity and locations of MIC-3: a unique root-specific defense-related gene family in Upland cotton (Gossypium hirsutum L.)

MIC-3 is a recently identified gene family shown to exhibit increased root-specific expression following nematode infection of cotton plants that are resistant to root-knot nematode. Here, we cloned and sequenced MIC-3 genes from selected diploid and tetraploid cotton species to reveal sequence differences at the molecular level and identify chromosomal locations of MIC-3 genes in Gossypium species. Detailed sequence analysis and phylogenetic clustering of MIC-3 genes indicated the presence of multiple MIC-3 gene members in Gossypium species. Haplotypes of a MIC-3 gene family member were discovered by comparative analysis among consensus sequences across genotypes within an individual clade in the phylogram to overcome the problem of duplicated loci in the tetraploid cotton. Deficiency tests of the SNPs delimited six A_t-genome members of the MIC-3 family clustered to chromosome arm 4sh, and one D_t-genome member to chromosome 19. Clustering was confirmed by long-PCR amplification of the intergenic regions using A_t-genome-specific MIC-3 primer pairs. The clustered distribution may have been favored by selection for responsiveness to evolving disease and/or pest pressures, because large variants of the MIC-3 gene family may have been recovered from small physical areas by recombination. This could give a buffer against selection pressure from a broad range of pest and pathogens in the future. To our knowledge, these are the first results on the evolution of clustering and genome-specific haplotype members of a unique cotton gene family associated with resistant response against a major pathogen.     

Nuclear translocation of cAMP-dependent protein kinase

A study was made of nuclear translocation of cAMP-dependent protein kinase and its subunits, as well as of the binding of these proteins to metaphase chromosomes. The CHO cell cultures were treated with ³H-labelled protein kinase and its subunits. The results indicate that cAMP-dependent protein kinase became translocated into the nucleus in a dissociated state and that the subunits have specific binding sites on chromatin. Transformation of normal mouse fibroblasts by virus SV40 interferes with the nuclear translocation of the regulatory subunit. The process is restored when the level of cAMP in the system is increased. Binding of the regulatory subunit to metaphase chromosomes of cells transformed by virus SV40 does not change. In the case of spontaneous cancer (KB cells) translocation of the regulatory subunit remains unaffected, whereas acceptance of the protein by the metaphase chromosomes is impeded. The results of this work suggest that compartmentalization of cAMP-dependent protein kinase—and particularly of its regulatory subunit—in the cell is highly significant for cellular processes. Disorders arising as a result of neoplastic transformation involve changes in nuclear translocation of the regulatory subunit and in its binding to the structural elements of the genome.     

Simple sequence repeat marker associated with a natural leaf defoliation trait in tetraploid cotton

Cotton (Gossypium hirsutum L.) leaf defoliation has a significant ecological and economical impact on cotton production. Thus the utilization of a natural leaf defoliation trait, which exists in wild diploid cotton species, in the development of tetraploid cultivated cotton will not only be cost effective, but will also facilitate production of very high-grade fiber. The primary goal of our research was to tag loci associated with natural leaf defoliation using microsatellite markers in Upland cotton. The F2 populations developed from reciprocal crosses between the two parental cotton lines--AN-Boyovut-2 (2n = 52), a late leaf defoliating type, and Listopad Beliy (2n = 52), a naturally early leaf defoliating type--demonstrated that the naturally early leaf defoliation trait has heritability values of 0.74 and 0.84 in the reciprocal F2 population. The observed phenotypic segregation difference in reciprocal crosses suggested a minor cytoplasmic effect in the phenotypic expression of the naturally early leaf defoliation trait. Results from the Kruskal-Wallis (KW) nonparametric test revealed that JESPR-13 (KW = 6.17), JESPR-153 (KW = 9.97), and JESPR-178 (KW = 13.45) Simple sequence repeat (SSR) markers are significantly associated with natural leaf defoliation in the mapping population having stable estimates at empirically obtained critical thresholds (P < .05-.0001). JESPR-178 revealed the highest estimates (P < .0001) for association with the natural leaf defoliation trait, exceeding maximum empirical threshold values. JESPR-178 was assigned to the short arm of chromosome 18, suggesting indirectly that genes associated with natural leaf defoliation might be located on this chromosome. This microsatellite marker may have the potential for use to introgress the naturally early leaf defoliation quantitative trait loci (QTL) from the donor line Listopad Beliy to commercial varieties of cotton through marker-assisted selection programs.     

Microorganisms Degrading Polychlorinated Biphenyls

Four strains belonging to the genus Bacilluscapable of degrading polychlorinated biphenyls (PCBs) were isolated by screening collection strains of soil bacteria degrading an organochlorine pesticide, hexachlorocyclohexane (HCCH). A method for production of tritium-labeled PCBs was developed. Consumption and degradation of PCBs by the soil bacterial strains selected were studied using tritium-labeled PCBs and GLC. It was demonstrated that PCBs are degradable both in culture media and in model soil samples.     

Influence of environmental conditions on the distribution of Central Asian green toads with three ploidy levels

We studied the distribution of Palearctic green toads (Bufo viridis subgroup), an anuran species group with three ploidy levels, inhabiting the Central Asian Amudarya River drainage. Various approaches (one‐way, multivariate, components variance analyses and maximum entropy modelling) were used to estimate the effect of altitude, precipitation, temperature and land vegetation covers on the distribution of toads. It is usually assumed that polyploid species occur in regions with harsher climatic conditions (higher latitudes, elevations, etc.), but for the green toads complex, we revealed a more intricate situation. The diploid species (Bufo shaartusiensis and Bufo turanensis) inhabit the arid lowlands (from 44 to 789 m a.s.l.), while tetraploid Bufo pewzowi were recorded in mountainous regions (340–3492 m a.s.l.) with usually lower temperatures and higher precipitation rates than in the region inhabited by diploid species. The triploid species Bufo baturae was found in the Pamirs (Tajikistan) at the highest altitudes (2503–3859 m a.s.l.) under the harshest climatic conditions.     

Phenol biodegradation by a Pseudomonas sp. strain tagged with the gfp gene

Conjugal transfer of the pAG408 suicide vector from E. coli S 17.1 to Pseudomonas sp. cells able to consume phenol yielded transconjugates brightly luminescing under UV illumination. It was shown that tagging of the Pseudomonas sp. cells with the gfp gene did not affect their ability to consume phenol. The change of the population density of the tagged bacteria after their introduction to soil was studied. The potential of the resulting bacterial strain in remediation of phenol-polluted soils is discussed.