Comparative characteristics of the intergenic spacer of the ribosomal RNA gene cluster in mosquitoes of the genus Culex (Diptera: Culicidae)

The intergenic spacer of the ribosomal RNA gene cluster (IGS) was sequenced for mosquitoes Culex modestus, C. torrentium, and C. pipiens pallens. The interpopulation variation of the IGS was estimated for the C. pipiens pipiens forms pipiens, which inhabits open waters, and molestus, which inhabits basements, of Russia. The IGSs of the Culex mosquitoes were not found to contain extended repetitive sequences characteristic of all known mosquito IGSs. At the same time, evolutionarily conserved motifs, relatively short degenerate sequences belonging to various classes of transposable elements, and multiple blocks of variable microsatellite repeats were identified. Based on the results, the IGS of the Culex mosquitoes was assumed to provide a promising molecular marker for population and phylogenetic analyses of the group.     

R1 and R2 retrotransposons of German cockroach Blattella germanica: comparative analysis of 5' truncated copies integrated into genome

This is the first report providing results on identification, cloning, and sequencing of extended fragments (5'-truncated copies) of R1 and R2 retrotransposons integrated into Blattella germanica genome. Comparative structural analysis of the received clones revealed two distinct subfamilies of R1 elements. However, all B. germanica R1 clones have two common features: poly(T) tails and similar target site duplications. Nucleotide structure and organization of five sequenced R2 fragments was similar. Analysis of R2 nucleotide sequences revealed typical deletions at the 3'end of target sites and lack of homopolynucleotides tails.     

Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.     

Nuclear rDNA variability in laboratory strains of the German cockroach Blattella germanica L. (Blattellidae)

The polymorphism of nuclear ribosomal DNA has been studied in male German cockroaches. The RFLP analysis has been used to identify seven types of HindIII fragments, the variation of which may serve as the basis for the differentiation of laboratory strains with respect to some population indices, including the average number of fragments per animal (N), the proportion of polymorphic loci (P), and the average pairwise similarity (APS). The interpopulation variation (FST) calculated for nine haplotypes is 53.85%.     

Variability of the mitochondrial gene for cytochrome oxidase I within the Adalia bipunctata species and within species of ladybird beetles (Coleoptera: Coccinellidae)

Intergeneric, interspecific, and intraspecific genetic variation of the 310-bp 3'-end region of the mitochondrial gene of cytochrome oxidase I (COI) has been assessed in ladybirds (Coleoptera: Coccinnellidae). The phylogenetic distances between eight species of ladybirds have been determined. Mitochondrial DNA (mtDNA) nucleotide sequences have been compared in Adalia bipunctata L. differing in the elytron and pronotum colors that have been sampled from several geographically remote populations. The taxonomic statuses of two morphs from the genus Adalia, A. bipunctata bipunctata and A. bipunctata fasciatopunctata, have been identified.     

Intraspecies polymorphism for the structural organization of ribosomal gene cluster in Blattella germanica

Intraspecific HindIII restriction fragment length polymorphism (RFLP) for the structural organization of the ribosomal gene cluster was described in Blattella germanica. In this species, homologous chromosomes were shown to contain ribosomal DNA (rDNA) repeats that differ in structure. The pattern of inheritance was determined for various structural variants of rDNA.