摘要:

AbstractUsing oligonucleotide primers derived from the aligned polypeptide sequences of several prokaryoticdnaAgenes, we amplified fromDrosophila melano‐gasterDNA a 557 bp fragment containing a single open reading frame. The predicted peptide sequence shows a significant similarity to previously characterized protein sequences that are encoded by thednaAgenes of several prokaryotes. ThednaAsequences are also detectable by PCR in DNA fromDrosophila simulansandNasonia vitripennisflies which are infected by a symbiotic bacterium assigned to the type speciesWolbachia pipientis.A tetracycline treatment that eradicates bacterial parasites from insects, abolishes thednaAsequences fromDrosophilaandNasoniaDNA. In addition, dnaA‐positiveDrosophila melano‐gastercontain numerous rod‐shaped bacteria in embryos, which are abolished in subsequent generations after treatment with tetracycline. Combined with phylogenetic analysis of DnaA and 16SrRNAsequences, these results show that thednaAcognate comes fromWolbachia.A survey ofDrosophilastocks using PCR amplification ofdnaAand 16SrRNAsequences showed thatWolbachiais widely spread amongD. melanogasterlaboratory strains but absent from several established strains of the Mediterranean fruit flyCeratitis capitata.Evidence is also presented that presence of the bacterium can cause partial cytoplasmic incompatibility between infected and non‐infectedD, melanogast

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00160.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractBiochemical and molecular studies have established that in the peach‐potato aphid,Myzus persicae,insecticide resistance is conferred by amplification of genes encoding the insecticide‐detoxifying esterases E4 or FE4. Here we report that two insecticide‐resistant clones of the closely related tobacco aphidMyzus nicotianaehave elevated esterases indistinguishable from E4 and FE4 and amplified esterase DNA sequences, and flanking regions, with identical restriction maps to theM. persicaegenes. Furthermore, the DNA sequences ofc.630 bp fragments of the E4 and FE4 genes ofM. persicaeare different from each other but identical to the fragment from correspondingM. nicotianaeclones. The existence of apparently identical insecticide resistance genes in the two species can be best explained by the selection of the amplified genes inM. persicae,transfer to hybrids ofM. persicaeandM. nicotianaeby sexual reproduction and subsequent spread throughM. nicotianaepopula

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00161.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractRAPD analysis technique is used as a rapid and reliable tool for genome analysis in the malaria vectorAnopheles gambiae.Using more than eighty different commercially available primers we identified more than sixty different DNA segments that were differentially amplified in different strains ofAn. gambiaes.s. andAn. arabiensis.An estimate of the cytogenetic position of these markers is provided by their hybridization to divisional dot‐blot filters. Potentially useful RAPD markers can be cytogenetically mapped with more precision byin situhybridization and, as they segregate as dominant markers in a Mendelian fashion, they can also be genetically mapped relative to other genes or rearrangements. Finally, we identified markers for their potential use in the identification of different mosquito strain

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00162.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractVarious protease inhibitors active against both trypsin‐ and chymotrypsin‐like serine proteases were used to characterize gut proteases fromLucilia cuprinabyin vitrofeeding assays. Significant larval growth retardation was observed on feeding first‐instar larvae with trypsin inhibitors, particularly soybean trypsin inhibitor. Feeding of chymostatin, a specific chymotrypsin inhibitor, resulted in no significant growth retardation. This information suggests that trypsin‐like serine proteases are probably the major gut digestive enzymes. A DNA fragment obtained by PCR which coded for part of a putative trypsin gene fromL. cuprinawas used to isolate a four‐member multigene family of trypsins. The full nucleotide sequence of one of the genes and partial sequence from the other three genes were determined. Transcription of at least one of the genes has been confirmed. All four of the genes appear to have arisen by two separate gene duplicati

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00163.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractSingle‐strand conformation polymorphism (SSCP) analysis detects single point mutations in DNA molecules. We demonstrate that SSCP analysis of mitochondrial ribosomal DNA (rDNA) genes is a sensitive taxonomic tool because these genes often differ at numerous sites among closely related species. Using conserved primers, portions of the 12S or 16S rDNA genes were amplified using the polymerase chain reaction (PCR) in congeneric species of ticks, leaf hoppers, mosquitoes, and closely related endoparasitic wasps. SSCP was performed and products were visualized with silver staining. Species‐specific patterns were observed in all taxa. Intraspecific variation at the level of single nucleotide substitutions was detected. SSCP diagnostics are less expensive and time consuming to develop than PCR with species‐specific primers, and, unlike PCR with arbitrary primers, there is minimal concern with DNA contamination from non‐target or

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00164.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe ribosomal DNA cistron from the large raspberry aphid,Amphorophora idaei(Hemiptera: Aphididae), has been mapped by restriction analysis. The results showed that the map ofA. idaeiwassimilar to those of the previously characterized aphidsSchizaphis grami‐num and Acyrthosiphon pisum.An extraBgltisite was found in some of the ribosomal DNA intergenic spacer repeats inA. idaei.Usingin‐situhybridization to aphid mitotic chromosomes it was demonstrated that probes derived from this region mapped to the pair of X chromosomes and it was therefore aphid in origin. Polymerase chain reaction using conserved rDNA primers also detected significant amounts of a fungal genome in the DNA samples. Microscopic investigation showed that the external surface ofA. idaeiharboured fungal propagules, hyphae and yeast‐like orga

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00165.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0962-1075    

DOI:10.1111/j.1365-2583.1994.tb00166.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY