摘要:

AbstractThe greenbug, Schizaphis graminum, is an aphid species that consists of races that can be separated based on morphology, life histories, cytogenetics, mitochondrial DNA RFLPs and virulence to plant culti‐vars. Variation in the greenbug rDNA multigene family was studied to determine the extent to which rDNA cistrons have diverged among and within races. A restriction map of the rDNA cistron was constructed. Probing DNA from different races with subclones from rDNA coding regions and internal spacers identified little variation. However, probing with subclones of the intergenic spacer (IGS) identified continuous length variation within and among races. Race specific patterns were identified. Within a race, almost continuous variation in total IGS length was detected and asexual lineages possessed distinct patterns useful in genetic fingerprinting studie

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00126.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn order to understand the regulation of trypsin genes by the blood meal, we constructed a cDNA library from mRNA isolated from midguts of blood‐fed female Aedes aegypti. The library was screened with a Dros‐ophila melanogaster trypsin‐like gene; twelve cDNAs were isolated and sequenced. Two clones were 846 bp and 788 bp long with 762 bp and 716 bp open reading frames, respectively. The cDNAs were identified as coding for serine proteases by the presence of conserved serine, histidine and aspartic acid residues; the presence of an aspartate residue at position 176 suggests that the clones were derived from trypsin‐like gene transcripts rather than chymotrypsin or other serine proteases. One of the clones contained a 5 untranslated region and coding regions for putative signal and activation peptides, suggesting that the product is secreted as an inactive zymogen and processed by autoactivation. Southern analysis of genomic DNA suggests that trypsin is encoded by a multi‐gene family in A

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00127.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe accumulation of transcripts from two adult‐specific cuticular genes (ACP‐20 and ACP‐22) is shown to be modified after addition of exogenous 20‐hydroxyecdysone. In the continuous presence of high levels of the hormone, the expression of ACP‐20 gene is significantly weaker than that of untreated controls, while ACP‐22 expression is 2.5‐fold increased. During active synthesis of the ACP messages, a 0.5 µ20‐hydroxyecdysone injection causes a rapid 2‐fold increase in ACP‐22 mRNA and is not able to repress ACP‐20 mRNA accumulation. We conclude that these genes whose transcripts appear in an almost coordinated manner in epidermal cells during the moulting cycle are regulated by ecdysteroids in a different way. In order to undertake a functional dissection of the promoter regions of ACP‐22 gene, we have isolated and sequenced a genomic clone. The sequence similarities with other cuticular pro

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00128.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA PCR primer from the mitochondrial COi gene is described that enhances the amplification of the COI‐COJI region of insect mtDNA. When used in conjunction with a primer from the COII gene identified by R. Crozier, a 1600–1700 bp segment is amplified in nine species of insects representing the orders Lepidop‐tera, Diptera, Coleoptera and Hymeno

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00129.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractFour Hsp70 genes of the malaria vector Anopheles albimanus were isolated from a genomic DNA library as two non‐overlapping clones each containing a pair of divergently transcribed genes having 75% DNA sequence similarity to the protein‐coding regions of the Drosophila metanogaster Hsp70genes. The clones were assigned to two loci on chromosome 2R by in situ hybridization. These clones hybridize strongly to heat‐shock but only weakly to non‐shocked mosquito RNA. The Hsp70 gene family of A. albimanus is undergoing concerted evolution probably by gene conversion. The general arrangement of the genes suggests that divergently transcribed pairs of genes at two loci is an ancient Dipteran arrangement predating the Nematocera/Cyclorrapha div

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00130.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe entire 15,363 bp mitochondrial genome was cloned and sequenced from the mosquitoAnopheles gambiae.With respect to the protein‐coding genes, rRN A genes and the control region, the gene order was identical to that reported for other insects. There were significant differences, however, in the position and orientation of specific tRNA loci. The overall nucleotide composition was heavily biased towards adenine and thymine, which accounted for 77.6% of all nucleotides. Comparisons were made with the mitochondrial genomes of other insects on the basis genome size and organization, DNA and putative amino acid sequence data, nucleotide substitutions, codon usage and bias, and patterns of AT enrichmen

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1993.tb00131.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY