Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| lipid metabolism in the symbiotes of the pea aphid, acyrthosiphon pisum. | 1976 | 6198 | |
| effect of dietary cholesterol on the pattern of osmium deposition in the symbiote-containing cells of the pea aphid. | pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. however, the staining of the per-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. in aphids cultured in vitro with 3h mevalonate in the presence of added cholesterol, th ... | 1977 | 64302 |
| in vivo sterol biosynthesis by pea aphid symbiotes as determined by digitonin and electron microscopic autoradiography. | pea aphid primary symbiotes have previously been shown to synthesize cholesterol in vitro. two electron microscopic techniques were used here to determine whether the symbiotes also synthesize cholesterol in vivo and whether this cholesterol is made available to the aphid. we also inquired into a possible role of secondary symbiotes in chosesterol biosynthesis. treatment of aphids with digitonin resulted in significant alteration of ultrastructural sites in primary and secondary symbiote membran ... | 1977 | 401684 |
| structural differences between pea enation mosaic virus strains affecting transmissibility by acyrthosiphon pisum (harris). | 1979 | 419684 | |
| a new approach to measure the lp50 of pea enation mosaic virus in its vector acyrthosiphon pisum. | 1978 | 726252 | |
| ultrastructure of pea aphid mycetocytes: evidence for symbiote secretion. | a detailed investigation into the ultrastructure of the pea aphid mycetocytes and their contained symbiotes and organelles was carried out with the transmission electron microscope. the most striking observation was the presence of small vesicles in the space between the primary symbiote cell wall and membrane envelope (outer membrane space). the vesicles appear to form by a budding process at the outer cell wall layer. subsequently, the vesicles, we suggest, may move out into the mycetocyte cyt ... | 1975 | 807329 |
| fate of pea enation mosaic virus in pemv-injected pea aphids. | 1975 | 1146226 | |
| nucleotide sequence and presumed secondary structure of the internal transcribed spacers of rdna of the pea aphid, acyrthosiphon pisum. | 1. internal transcribed spacer (its) 1 and its 2 of rdna of the pea aphid, acyrthosiphon pisum consisted of 229 and 280 nucleotides, whose g+c contents were 70 and 74%, respectively. 2. secondary structure models constructed for the its 1 and its 2 suggested that certain structural motifs have been conserved in these regions despite extensive divergence in nucleotide sequence due to species. | 1992 | 1458839 |
| [histology of insect infection by entomopathogenic fungi: interest in a new procedure for the study of precocious phases]. | infective and invasive processes of entomopathogenic fungi expected to be used in biological control shall be analysed in detail. histological and ultrastructural studies are therefore essential. this paper is devoted to the field of light microscopy; its purpose is to show that coating, in a 4% agar solution, the insects infected by a fungus, prior to fixation and embedding, allows the preservation of the fungal structures present on the cuticle, especially the germinating conidia. this is usef ... | 1992 | 1596963 |
| unique structure in the intergenic and 5' external transcribed spacer of the ribosomal rna gene from the pea aphid acyrthosiphon pisum. | we analyzed the dna sequence of the 5' external transcribed spacer (ets) and part of the intergenic transcribed spacer (igs) of the aphid ribosomal rna gene (rdna). the 5' ets of aphid rdna consists of 843 nucleotides with a g/c content of 69 mol/100 mol, far higher than that of any other known 5' ets for insect rdna. the igs of aphid rdna contained a characteristic array of repeated sequences of 247 nucleotides. the repeated sequences were identical. it was shown that the number of the repeatin ... | 1992 | 1606971 |
| mutualism based on stress: selective synthesis and phosphorylation of a stress protein by an intracellular symbiont. | the effects of a temperature shift-up and various metabolic inhibitors on the protein synthesis of an endosymbiont isolated from the pea aphid were studied. the syntheses of at least three major polypeptides were stimulated transiently immediately after a temperature shift-up, and treatment with ethanol and heavy metals (cd2+ and as2+). one of these proteins, the 63 kda heat-shock protein (63-kda hsp), was immunoprecipitated with antiserum raised against symbionin, which is selectively synthesiz ... | 1992 | 1618730 |
| the longest 18s ribosomal rna ever known. nucleotide sequence and presumed secondary structure of the 18s rrna of the pea aphid, acyrthosiphon pisum. | an embl4 recombinant phage which encodes one of the full length of the aphid ribosomal dna has been isolated from the aphid genomic library. determination of the complete nucleotide sequence of the aphid 18s rrna gene revealed that it is 2469 bp with a g + c content of 59%. the aphid 18s rrna gene studied here is the longest and has the highest g + c content among the 18s rrna genes examined so far. evidence provided by the s1 nuclease assay suggests that the aphid 18s rrna gene examined in this ... | 1991 | 1765096 |
| pea aphid symbiont relationships established by analysis of 16s rrnas. | the pea aphid (acyrthosiphon pisum harris) harbors two morphologically distinct procaryotic intracellular symbionts. the genes for the 16s rrna from these symbionts have been cloned and sequenced. comparisons with sequences of 16s rrnas from selected procaryotes indicate that the two symbionts are evolutionarily distinct from each other and are members of the gamma-3 subdivision of the class proteobacteria. one of the symbionts is a member of the family enterobacteriaceae, while the other consti ... | 1989 | 2470724 |
| protein synthesis by intracellular symbionts in two closely interrelated aphid species. | an aphid endosymbiont in vivo synthesizes symbionin almost exclusively which is not produced in vitro by the same symbiont. while symbionin produced by the endosymbiont of the pea aphid is an acidic protein with a molecular weight of 63,000, that by the symbiont of the kondo aphid, the closest relative to the former, is a distinct, less acidic, molecule. while the two endosymbionts in vivo in old insects synthesize about 11 protein species in common, they produce many different proteins when inc ... | 1985 | 3931719 |
| purification of pea enation mosaic virus from its pea aphid vector, acyrthosiphon pisum, and aphid-transmission characteristics. | 1973 | 4119354 | |
| maintenance of the primary symbiote of the pea aphid acyrthosiphon pisum in liquid media. | 1974 | 4212152 | |
| effects of antibiotics on intracellular symbiotes in the pea aphid, acyrthosiphon pisum. | 1974 | 4364847 | |
| the fate of pea enation mosaic virus in its pea aphid vector, acyrthosiphon pisum (harris). | 1972 | 4565616 | |
| cyolane and cytrolane performance against pea aphids on alfalfa in two climatically different localities. | 1973 | 4690265 | |
| amino acid requirements and sulfur amino acid metabolism in the pea aphid, acrythosiphon pisum (harris). | 1968 | 4967904 | |
| [cholinesterase of the pea aphid acyrthosiphon pisi kalt]. | 2007 | 5045105 | |
| correlation of transmission of bean yellow mosaic virus with salivation activity of acyrthosiphon pisum (homoptera: aphididae). | 1969 | 5374177 | |
| simultaneous transmission of two pea viruses by acyrthosiphon pisum quantified on sweetpea as diagnostic local lesions. | 1969 | 5377738 | |
| electron-microscope investigations of bacterial flora in the alimentary tract of acyrthosiphon pisum (harris). | 1969 | 5383865 | |
| [embryonal development of the pea aphid acyrthosiphon pisum harris (homoptera, aphidiae)]. | 1970 | 5457502 | |
| [migration and parasitism of the pea aphid acyrthosiphon pisum (harris)]. | 1970 | 5480193 | |
| [diapause of eggs from the pea aphid (acyrthosiphon onobrychis boyer, homoptera, aphididae)]. | 1970 | 5529642 | |
| "recharging" pea aphids with pea enation mosaic virus. | 1966 | 5928791 | |
| aspects of mineral nutrition of the pea aphid, acyrthosiphon pisum (harris). | 1967 | 6028303 | |
| retention of inoculativity in the transmission of pea enation mosaic virus by pea aphids as associated with virus isolates, aphid reproduction and excretion. | 1967 | 6028944 | |
| differential transmission of two pea enation mosaic virus isolates by the pea aphid, acyrthosiphon pisum (harris). | 1967 | 6062176 | |
| difference in the transmission of pea leaf rolling virus by two strains of pea aphid acyrthosiphon pisum harris. | 1967 | 6062274 | |
| intraspecies variability in transmission efficiency of stylet-borne viruses by the pea aphid (acyrthosiphon pisum). | the efficiency of bean yellow mosaic virus (bymv; potyvirus group) tranasmission from pea to pea plants by 36 clones of the pea aphid (acyrthosiphon pisum) was studied. the efficiency of the clones varied; it was not related to the aphid colour form (green, red or yellow) or the origin of the clone (host plant, geographic area). with alfalfa mosaic virus, the virus-vector relationships concerning transmission efficiency were, in general, similar to those found with bymv. the behaviour of the clo ... | 1980 | 6108064 |
| cloning and characterization of the ribosomal protein genes in the spc operon of a prokaryotic endosymbiont of the pea aphid, acyrthosiphon kondoi. | to correlate a prokaryotic endosymbiont in the pea aphid, acyrthosiphon kondoi, with the endosymbionts in related aphid species as well as with free-living bacteria and subcellular organelles, and to study the mode of its gene expression within aphid cells, we have cloned and characterized the genes encoding ribosomal proteins s3, l16, l29, s17, l14, l24, l5, s14, s8, l6, l18, s5, l30, l15 and secretion protein y (sec y) from the s10 and spc ribosomal protein gene operons of this endosymbiont. t ... | 1994 | 7584036 |
| phylogenetic affiliation of bev, a bacterial parasite of the leafhopper euscelidius variegatus, on the basis of 16s rdna sequences. | the phylogenetic relationship of a nonflagellated, gram-negative, rod-shaped intracellular bacterial parasite (bev) of the leafhopper euscelidius variegatus to other bacteria within the class proteobacteria was determined by sequence analysis of 16s rdnas. the presence of specific signature nucleotides showed this bacterium to be a member of the gamma-3 subdivision of the proteobacteria. phylogenetic analysis based on maximum parsimony placed bev within a clade in the enterobacteriaceae, which i ... | 1993 | 7763405 |
| an association between phlebotomine sandflies and aphids in the peruvian andes. | as the composition of natural sugars in the diet of adult sandflies (diptera: psychodidae: phlebotominae) may affect the development of leishmania (kinetoplastida: trypanosomatidae) in sandfly guts, and so play an important role in the epidemiology of leishmaniasis, there is increasing interest in the sources of sugars for wild sandflies. advanced chromatography techniques have provided indirect evidence that wild sandflies feed on honeydew, a substance released by aphids (hemiptera: aphididae) ... | 1995 | 7787219 |
| molecular analysis of ribosomal dna from the aphid amphorophora idaei and an associated fungal organism. | the ribosomal dna cistron from the large raspberry aphid, amphorophora idaei (hemiptera: aphididae), has been mapped by restriction analysis. the results showed that the map of a. idaei was similar to those of the previously characterized aphids schizaphis graminum and acyrthosiphon pisum. an extra bgl ii site was found in some of the ribosomal dna intergenic spacer repeats in a. idaei. using in-situ hybridization to aphid mitotic chromosomes it was demonstrated that probes derived from this reg ... | 1994 | 7894750 |
| an endosymbiont chaperonin is a novel type of histidine protein kinase. | symbionin, a groel homologous molecular chaperone produced by an intracellular symbiont of the pea aphid, is able to transfer its high-energy phosphate bond to other compounds through its autophosphorylation. when the urea-dissociated monomeric symbionin fixed onto a polyvinylidene difluoride membrane was incubated with [gamma-32p] atp, it was efficiently phosphorylated at elevated temperatures. the autophosphorylated monomeric 32p-labeled symbionin, when incubated with adp, transferred a signif ... | 1994 | 7896735 |
| chaperonin produced by an intracellular symbiont is an energy-coupling protein with phosphotransferase activity. | symbionin, a groel homologous molecular chaperone produced by an intracellular symbiont of the pea aphid, is autocatalytically phosphorylated in vitro at elevated temperatures. the phosphorylated symbionin showed a potent suppressive activity in spontaneous refolding of chemically denatured dihydrofolate reductase. when the 32p-labeled autophosphorylated symbionin was incubated with adp, a portion of the radioactivity was transferred to adp, suggesting that the autocatalytically phosphorylated s ... | 1993 | 7903296 |
| gut microbe of aphid closely related to its intracellular symbiont. | pea aphid, acyrthosiphon pisum harbors prokaryotic intracellular symbionts and, at least, two species of gut microbes. it has been shown that the aphid symbiont is more closely related to escherichia coli than to any other free-living bacterium. analysis of rflp of their 16s rdna and groe homologues suggested that one of the gut microbes is a close relative of e. coli and that the aphid symbiont is still closer to this microbe than to e. coli. in addition, the optimal temperature for the growth ... | 1993 | 7908835 |
| mitochondrial dna diversity in the pea aphid acyrthosiphon pisum. | the pea aphid acyrthosiphon pisum has been established in north america for at least a century and occurs on a broad range of host plants. despite its importance as a crop pest, there is little understanding of the genetic structure of its populations or the extent of genetic divergence associated with different host plant utilization. this study examined the extent of mitochondrial dna (mtdna) diversity among 35 clones of pea aphids from alfalfa. polymorphisms were detected at only 2 of 126 res ... | 1994 | 8001815 |
| differentiation of aphid clones by arbitrarily primed polymerase chain reaction (ap-pcr) dna fingerprinting. | differentiation of aphid clones was attempted using ap-pcr which is a simple and rapid method to obtain dna fingerprints of complex genomes. to establish optimal reaction conditions and examine reproducibility of the method, a laboratory-maintained clone of the pea aphid, acyrthosiphon pisum, was used as test material. under the reaction conditions employed, identical fingerprint patterns were obtained throughout a wide range of template dna amount, from 5 to 800 ng, and irrespective of aphid in ... | 1994 | 8061876 |
| the 'tubulin-like' s1 protein of spirochaeta is a member of the hsp65 stress protein family. | a 65-kda protein (called s1) from spirochaeta bajacaliforniensis was identified as 'tubulin-like' because it cross-reacted with at least four different antisera raised against tubulin and was isolated, with a co-polymerizing 45-kda protein, by warm-cold cycling procedures used to purify tubulin from mammalian brain. furthermore, at least three genera of non-cultivable symbiotic spirochetes (pillotina, diplocalyx, and hollandina) that contain conspicuous 24-nm cytoplasmic tubules displayed a stro ... | 1993 | 8155849 |
| the tryptophan biosynthetic pathway of aphid endosymbionts (buchnera): genetics and evolution of plasmid-associated anthranilate synthase (trpeg) within the aphididae. | the bacterial endosymbionts (buchnera) from the aphids rhopalosiphum padi, r. maidis, schizaphis graminum, and acyrthosiphon pisum contain the genes for anthranilate synthase (trpeg) on plasmids made up of one or more 3.6-kb units. anthranilate synthase is the first as well as the rate-limiting enzyme in the tryptophan biosynthetic pathway. the amplification of trpeg on plasmids may result in an increase of enzyme protein and overproduction of this essential amino acid, which is required by the ... | 1996 | 8642610 |
| a new rickettsia from a herbivorous insect, the pea aphid acyrthosiphon pisum (harris). | an undescribed, maternally heritable, rod-shaped bacterium (or "tertiary symbiont") was detected by microscopy in hemolymph of about half (59/122) of pea aphid [acyrthosiphon pisum (harris)] clones collected from widely separated locations in california. on the basis of molecular phylogenetic analysis of 16s rdna sequences, the bacterium was clearly placed among other rickettsia in the alpha-subgroup of proteobacteria, close to rickettsia bellii-a rickettsia found in ticks. a pcr assay was devel ... | 1996 | 8662184 |
| ribosomal dna is frequently concentrated on only one x chromosome in permanently apomictic aphids, but this does not inhibit male determination. | the ribosomal dna arrays in the nucleolar organizer regions (nors) of aphids are generally-located in a telomeric or subtelomeric position on the x chromosomes. in aphid populations or species that have lost the sexual part of their life cycle and become permanent apomicts, multiple rdna copies are often concentrated on only one of the original x chromosomes. this situation has been found in apomictic members of three aphid subfamilies, although not as yet in the tribe aphidini, which includes s ... | 1996 | 8817074 |
| nucleotide sequence and presumed secondary structure of the 28s rrna of pea aphid: implication for diversification of insect rrna. | determination of the entire nucleotide sequence of the aphid 28s ribosomal rna gene (28s rdna) revealed that it is 4,147 bp in length with a g + c content of 60.3%. based on the nucleotide sequence, we constructed a presumed secondary-structure model of the aphid 28s rrna which indicated that the aphid 28s rrna is characterized by the length and high g + c content of its variable regions. the g + c content of the aphid's variable regions was much higher than that of the entire sequence of the 28 ... | 1996 | 8875861 |
| in vitro interactions of the aphid endosymbiotic syml chaperonin with barley yellow dwarf virus. | barley yellow dwarf virus (bydv)-vector relationships suggest that there are specific interactions between bydv virions and the aphid's cellular components. however, little is known about vector factors that mediate virion recognition, cellular trafficking, and accumulation within the aphid. symbionins are molecular chaperonins produced by intracellular endosymbiotic bacteria and are the most abundant proteins found in aphids. to elucidate the potential role of symbionins in bydv transmission, w ... | 1997 | 8985385 |
| occurrence and transmission of facultative endosymbionts in aphids. | the occurrence of a secondary bacterial symbiont (pass) of pea aphid, acyrthosiphon pisum (harris), was detected by polymerase chain reaction (pcr) with specific nucleotide primers based on pass 16s rdna nucleotide sequences from over 80% (50/57) of clones of pea aphid collected from widely separated locations in california. pass was also detected by pcr in both red and green phenotypes of rose aphid,macrosiphum rosae (l.), but not in six other species of aphids examined, including blue alfalfa ... | 1997 | 9058541 |
| structure of the dnaa region of the endosymbiont, buchnera aphidicola, of aphid schizaphis graminum. | buchnera aphidicola is an intracellular prokaryote (endosymbiont) that lives in the body cavity of the aphid. phylogenetic studies indicated that it is closely related to escherichia coli and members of enterobacteria. the gene order of the region containing the dnaa gene is well conserved in many bacteria. seven genes of the endosymbiont of the aphid schizaphis graminum, gyrb, dnan, dnaa, rpmh, rnpa, yidd, and 60k. were found to be homologous in sequence and relative location to those of e. col ... | 1996 | 9097044 |
| a comparison of acute mortality and population growth rate as endpoints of toxicological effect. | the objective of this study was to determine how closely acute (72-hr) lethal concentration estimates developed from probit analysis compared to the demographic toxicological endpoints, net reproductive rate (ro), the intrinsic rate of increase (rm), and realized fecundity (ux), in terms of predicting effects of pesticides on populations. lethal and sublethal effects of the insecticide imidacloprid on the arthropod acyrthosiphon pisum harris (pea aphid) were determined for populations exposed to ... | 1997 | 9212335 |
| structure and expression of the dnakj operon of buchnera, an intracellular symbiotic bacteria of aphid. | buchnera sp., an intracellular symbiont of the pea aphid (acyrthosiphon pisum harris), is a close phylogenetical relative of escherichia coli, and synthesizes a large amount of symbionin, a groel homolog. the other heat shock protein homologs, which are not expressed as much as symbionin, have not been studied yet. in this study, we cloned the dnak and dnaj genes of buchnera, and revealed that its dnak and dnaj are structurally very similar to those of e. coli. amino acid residues and motifs pro ... | 1997 | 9276669 |
| uptake, excretion and respiration of sucrose and amino acids in the pea aphid acyrthosiphon pisum | ingestion, excretion and respiration in aphids were studied using artificial diets labelled with radioactive sucrose or amino acids. the rate of ingestion of a 25 % w/v sucrose diet was 12.4 nl mg-1 h-1 and the honeydew excretion rate was 5.3 nl mg-1 h-1, about 43 % of the volume ingested during the same period. the concentration of sugars in the honeydew was equivalent to 0.53 mol l-1 sucrose and 69 % of the sucrose ingested was assimilated. the amino acid concentration of honeydew was 24.6 mmo ... | 1996 | 9319135 |
| honeydew sugars and osmoregulation in the pea aphid acyrthosiphon pisum | pea aphids, acyrthosiphon pisum, containing their symbiotic bacteria (untreated aphids) and experimentally deprived of their bacteria by treatment with the antibiotic rifampicin (antibiotic-treated aphids) were reared on the plant vicia faba. the sugars in the honeydew produced by untreated aphids comprised predominantly the monosaccharides glucose and fructose, while the honeydew of antibiotic-treated aphids contained considerable amounts of oligosaccharides of up to 16 hexose units. the honeyd ... | 1997 | 9320049 |
| characteristics of acyrthosiphon pisum virus, a newly identified virus infecting the pea aphid. | a new virus was isolated from the pea aphid, acyrthosiphon pisum, and tentatively named acyrthosiphon pisum virus (apv). the isometric virus particles were approximately 31 nm in diameter and contained a single-stranded rna molecule of approximately 10 kb. four structural proteins were observed with molecular masses of approximately 23.3, 24.2, 34.5, and 66.2 kda. the 34.5-kda capsid protein was the most abundant product in purified virions. computer-assisted analysis revealed no significant hom ... | 1997 | 9367722 |
| nucleotide sequence and genomic organization of acyrthosiphon pisum virus. | the nucleotide sequence of the genomic rna of acyrthosiphon pisum virus was determined. the apv genome is 10,016 nucleotides in length, excluding the 3'-end poly(a) track, and contains two large open reading frames (orfs), encoding proteins of 296,340 and 63,279 da. the orf1 is preceded by an untranslated leader sequence of 267 nucleotides. the orf1 product contains sequence motifs characteristic of rna-dependent rna polymerases, chymotrypsin-like proteases, and helicases. interviral sequence co ... | 1997 | 9400608 |
| implications of predator foraging on aphid pathogen dynamics. | the foraging behavior of starved and nonstarved second and fourth instar coccinella septempunctata larvae on dead acyrthosiphon pisum aphids, either infected with the entomopathogenic fungus erynia neoaphidis (sporulating) or uninfected, was examined. larvae searched for longer and fed less when presented with infected rather than uninfected a. pisum. although no sporulating infected aphids were completely consumed, both adult and larval ladybirds can still be considered as intraguild predators. ... | 1998 | 9538028 |
| comparison of ecdysteroid concentration in different morphs of aphids. | the amounts of ecdysteroids were determined in different morphs of holocyclic monoecious aphids (acyrthosiphon pisum harris, dysaphis devecta walk., lachnus roboris l., schizolachnus pineti f.) and holocyclic heteroecious aphids (aphis sambuci l., rhopalosiphum padi l.) by means enzyme immunoassay. among the parthenogenetic morphs (fundatrices, virginoparae, and oviparae), the fundatrices have consistently higher amounts of ecdysteroids than those of other morphs of the same species. alate and a ... | 1996 | 9568366 |
| differential display of mrnas related to amino acid metabolism in the endosymbiotic system of aphids. | bacteriocytes harbouring buchnera endosymbionts were isolated from young and old aphids, acyrthosiphon pisum, and their mrna populations were examined by the differential cdna display and quantitative reverse transcriptase-polymerase chain reaction (rt-pcr) technique. it was suggested that several gene products are produced when the symbiotic system is well organized in the young insect, whereas others are produced after the system becomes degenerate in old aphids. among the gene products that w ... | 1997 | 9569646 |
| method to immobilize the aphid-pathogenic fungus erynia neoaphidis in an alginate matrix for biocontrol | erynia neoaphidis is an important fungal pathogen of aphid pests worldwide. there have been few reported attempts to formulate this natural agent for use in biocontrol. in the current study, factors involved in the immobilization of e. neoaphidis hyphae in an alginate matrix were investigated. hyphae of two isolates cultured in liquid medium were 220 to 620 &mgr;m in length and 7 to 19 &mgr;m in diameter with a 74 to 83% cytoplasmic content. the optimal concentration of low-viscosity sodium algi ... | 1998 | 9797274 |
| molecular evidence against phylogenetically distinct host races of the pea aphid (acyrthosiphon pisum). | pea aphid (acyrthosiphon pisum) clones have been shown to be adapted to particular host plant species but it is unknown whether there are host races. a 1101 base pair region of the mitochondrial cytochrome oxidase i gene (coi) was sequenced for 21 pea aphid clones that had been collected from different host plants in canada and the u.s.a. only five closely related mitochondrial haplotypes were found. a maximum likelihood phylogeny was estimated for these five haplotypes and four related aphid sp ... | 1998 | 9924789 |
| physical and genetic map of the genome of buchnera, the primary endosymbiont of the pea aphid acyrthosiphon pisum. | the genome of buchnera, an endosymbiotic bacterium of the pea aphid acyrthosiphon pisum, was characterized by pulse-field gel electrophoresis (pfge) as a circular dna molecule of 657 kb. the enzymes i-ceui, cpoi, apai, smai, naei, sacii, mlui, fspi, and nrui were used to cleave the dna of buchnera into fragments of suitable size for pfge analysis. a physical map of the buchnera genome, including restriction fragments from seven of these enzymes, was constructed using double cutting, partial dige ... | 1999 | 9929382 |
| importance of population structure at the time of toxicant exposure. | populations in nature often consist of a mixture of stages and ages, yet toxicological studies even demographic studies, usually evaluate one starting life stage. in this study it was asked whether the starting age/stage structure of a population at the time of initial pesticide exposure influenced the impact that pesticides have on population growth rates. this question was answered by exposing differently structured populations of two terrestrial arthropod species, the two-spotted spider mite, ... | 1999 | 10090817 |
| the role of rdna genes in x chromosome association in the aphid acyrthosiphon pisum. | silver staining of mitotic metaphases of the aphid a. pisum reveals the presence of argentophilic bridges connecting the two x chromosomes. the presence of nucleolar material connecting sex chromosomes seems to be quite a common phenomenon in organisms belonging to very different phyla, and suggests a role of nucleolar proteins in chromosome association and disjunction. in somatic cells of a. pisum, bridges connecting x chromosomes are detectable not only after silver staining but also after cma ... | 1999 | 10382287 |
| low genetic diversity among pea aphid (acyrthosiphon pisum) biotypes of different plant affiliation. | genetic diversity in the pea aphid acyrthosiphon pisum was investigated by a restriction fragment length polymorphism (rflp) analysis of three maternally inherited genomes (mitochondrial dna and plasmids of the symbiotic bacteria buchnera). twenty-nine parthenogenetic clones of three a. pisum biotypes, defined by their capacity to use the legume crops pea, alfalfa and red clover, respectively, were analysed, and a total of 67 restriction sites was scored. no restriction site variation in the mit ... | 1999 | 10383681 |
| effects of fungal infection on the alarm response of pea aphids | pea aphids (acyrthosiphon pisum, homoptera: aphididae) infected with the fungal pathogen erynia neoaphidis (zygomycetes: entomophthorales) were less sensitive to the aphid alarm pheromone (e)-beta-farnesene than uninfected aphids. approximately 83% of the healthy aphids and 45% of the infected aphids (2 and 3 days post-inoculation) responded to the alarm pheromone. the percentage of nonresponding aphids increased as the disease progressed. when squeezed (simulated attack) healthy aphids and aphi ... | 1999 | 10388549 |
| fate of dietary sucrose and neosynthesis of amino acids in the pea aphid, acyrthosiphon pisum, reared on different diets | the fate of sucrose, the major nutrient of an aphid's natural food, was explored by radiolabeling in the pea aphid acyrthosiphon pisum. to investigate the influence of nitrogen quality of food on amino acid neosynthesis, pea aphids were reared on two artificial diets differing in their amino acid composition. the first (diet a) had an equilibrated amino acid balance, similar to that derived from analysis of aphid carcass, and the other (diet b) had an unbalanced amino acid composition similar to ... | 1999 | 10482723 |
| isolation and characterization of apse-1, a bacteriophage infecting the secondary endosymbiont of acyrthosiphon pisum. | a bacteriophage infecting the secondary endosymbiont of the pea aphid acyrthosiphon pisum was isolated and characterized. the phage was tentatively named bacteriophage apse-1, for bacteriophage 1 of the a. pisum secondary endosymbiont. the apse-1 phage particles morphologically resembled those of species of the podoviridae. the complete nucleotide sequence of the bacteriophage apse-1 genome was elucidated, and its genomic organization was deduced. the genome consists of a circularly permuted and ... | 1999 | 10489345 |
| faba bean necrotic yellows virus (genus nanovirus) requires a helper factor for its aphid transmission. | purified faba bean necrotic yellows virus (fbnyv; genus nanovirus) alone is not transmissible by its aphid vector, acyrthosiphon pisum, regardless of whether it is acquired from artificial diets or directly microinjected into the aphid's hemocoel. the purified virus contains all of the genetic information required for its infection cycle as it readily replicated in cowpea protoplasts and systemically infected vicia faba seedlings that were biolistically inoculated using gold particles coated wit ... | 1999 | 10489354 |
| aphids, predators and parasitoids. | a number of studies have demonstrated the role of herbivore-induced release of plant volatiles in mediating foraging behaviour of aphid parasitoids, particularly with the parasitoid aphidius ervi, its aphid host acyrthosiphon pisum and the aphid food plant vicia faba. these studies have shown that feeding by the aphid alters the composition of volatiles released by the plant and that these compounds act as synomones for the foraging parasitoid. of particular interest is the species-specificity o ... | 1999 | 10549548 |
| variability and parasitoid foraging efficiency: a case study of pea aphids and aphidius ervi. | when a parasitoid is searching for hosts, not all hosts are equally likely to be attacked. this variability in attack probability may affect the parasitoid functional response. using a collection of experiments, we quantified the functional response of aphidius ervi (hymenoptera: braconidae), an insect parasitoid of the pea aphid acyrthosiphon pisum (homoptera: aphididae). we measured variability in the number of hosts attacked by a foraging parasitoid both among plants and within plants. at the ... | 1999 | 10600611 |
| acetone preservation: a practical technique for molecular analysis. | in attempts to establish a convenient and reliable method for field collection and archival preservation of insects and their endosymbiotic microorganisms for molecular analysis, acetone, ethanol, and other organic solvents were tested for dna preservability of the pea aphid acyrthosiphon pisum and its intracellular symbiotic bacterium buchnera sp. after 6 months' storage, not only the band of high-molecular-size dna but also the bands of rrna were well preserved in acetone, ethanol, 2-propanol, ... | 1999 | 10620236 |
| molecular characterization of the leucine plasmid from buchnera aphidicola, primary endosymbiont of the aphid acyrthosiphon pisum. | the complete sequence of the leucine plasmid of buchnera aphidicola from the aphid acyrthosiphon pisum (pleu-bap) is reported. its gene organization was concordant with those of other leucine plasmids of buchnera from aphids of the aphidini and macrosiphini tribes. three inverted repeats are present in pleu-bap. two of them are also present in pleu from the family aphididae: (i) sir1, located downstream the leucine operon, resembles a rho-independent terminator of transcription, and (ii) lir1, l ... | 2000 | 10688696 |
| prephenate dehydratase from the aphid endosymbiont (buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibition by phenylalanine. | buchnera aphidicola, the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. we have cloned and sequenced a region of the genome of b. aphidicola isolated from acyrthosiphon pisum which includes the two-domain aroq/phea gene. this gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l-phenylalanine biosynthesis. two changes involved in the overproduction of ... | 2000 | 10781569 |
| the influence of parasitism on wing development in male and female pea aphids. | wing formation in presumptive alate morphs (virginoparae and males) was observed for the pea aphid, acyrthosiphon pisum, exposed to attack by the parasitoid, aphidius ervi, at different stages of host development. morphological abnormalities in parasitized aphids such as complete apterization (development of a wingless form), formation of rudimentary wing buds, and deformed wings indicate a possible disruption of the endocrine system. changes in the body shape and the number of olfactory seconda ... | 2000 | 10802097 |
| host castration by aphidius ervi venom proteins. | the braconid aphidius ervi haliday (hymenoptera, braconidae) is an endophagous parasitoid of the pea aphid, acyrthosiphon pisum (harris) (homoptera, aphididae). parasitized host aphids show different degrees of castration, a response that is total when parasitoid oviposition takes place in first instar hosts. deleterious effects on the host reproductive system are already evident by 24h following parasitization, before egg hatching. the effect of parasitoid venom on a. pisum ovaries has been stu ... | 2000 | 10802117 |
| salivary proteins of aphids, a pilot study on identification, separation and immunolocalisation. | salivary proteins (sps) of schizaphis graminum, acyrthosiphon pisum and myzus persicae were studied after probing and feeding on different artificial diets. salivary sheaths as well as apical lumps of saliva were found, presumably representing subsequently excreted saliva of different types. phenoloxidase, pectinase and peroxidase activities were detected by staining the enzyme-converted products, thus confirming these enzyme activities found earlier by others. proteinase and cellulase were not ... | 2000 | 10818245 |
| effect of nymphal diet on adult predation behavior in orius majusculus (heteroptera: anthocoridae). | the predatory bug orius majusculus (reuter) was reared on 2 different diets during the nymphal stages. the 1st group was exclusively offered eggs of ephestia kuehniella zeller (lepidoptera: pyralidae), a standard diet for o. majusculus production. the 2nd group was exclusively offered 4th instars of the pea aphid, acyrtosiphon pisum (harris). subsequently, adult predatory behavior in experimental arenas containing a. pisium was recorded using 2 video cameras. one camera permitted observation of ... | 2000 | 10826169 |
| the secondary endosymbiotic bacterium of the pea aphid acyrthosiphon pisum (insecta: homoptera). | the secondary intracellular symbiotic bacterium (s-symbiont) of the pea aphid acyrthosiphon pisum was investigated to determine its prevalence among strains, its phylogenetic position, its localization in the host insect, its ultrastructure, and the cytology of the endosymbiotic system. a total of 14 aphid strains were examined, and the s-symbiont was detected in 4 japanese strains by diagnostic pcr. two types of eubacterial 16s ribosomal dna sequences were identified in disymbiotic strains; one ... | 2000 | 10877764 |
| clones of pea aphid, acyrthosiphon pisum (hemiptera: aphididae) distinguished using genetic markers, differ in their damaging effect on a resistant alfalfa cultivar. | cuf 101, a resistant cultivar of alfalfa, was exposed to 15 clones of acyrthosiphon pisum harris collected from alfalfa fields in three regions of france (east, south, central west) to determine whether the level of resistance varied across the different clones. the survival of alfalfa seedlings infested at the cotyledon stage was assessed using a standardized method. although no difference in seedling mortality was detected between clones grouped by region, there was a significant variation amo ... | 2000 | 10948361 |
| reproductive isolation between divergent races of pea aphids on two hosts. ii. selection against migrants and hybrids in the parental environments. | sympatric races of pea aphids on alfalfa and red clover are highly ecologically specialized and significantly reproductively isolated. much of the restriction of gene flow between the specialized populations is due to habitat choice behavior of the winged colonizers (via 1999). here, we document additional pre- and postmating reproductive isolation through selection against migrants and hybrids in the parental environments. first, a group of randomly chosen genotypes from each race that were exp ... | 2000 | 11108590 |
| chromosome analysis and molecular characterization of highly repeated dnas in the aphid acyrthosiphon pisum (aphididae, hemiptera). | despite the interest in aphid biology, information on chromatin organization of their holocentric chromosomes is still limited to few species. in order to fill this gap, we have performed an extensive survey on pea aphid mitotic chromosomes using both classical and molecular cytogenetic techniques. our results after silver, cma3 and dapi-staining, c-banding and fluorescent in situ hybridization (fish) using 28s rdna and 5s rdna as probes evidenced a tendency of repetitive dnas to be concentrated ... | 2000 | 11138948 |
| behavioural thermoregulation in acyrthosiphon pisum (homoptera: aphididae): the effect of parasitism by aphidius ervi (hymenoptera: braconidae). | the effects of parasitisation by aphidius ervi on the thermoregulatory behaviour of the pea aphid acyrtosiphon pisum were studied in alfalfa fields and in an experimental thermal gradient. in the field, mummies were found exclusively on the adaxial surface of the upper leaves, and aphids in the mid canopy. the adaxial surface of the upper leaves was ca. 2 degrees c hotter that the mid-canopy. in the thermal gradient, the thermal effect (selected minus exposure temperature) was higher in magnitud ... | 2001 | 11163929 |
| effect of temperature and cultivar on pea aphid, acyrthosiphon pisum (hemiptera: aphididae) life history. | life history parameters of the pea aphid, acyrthosiphon pisum were studied at five constant temperatures on two cultivars of peas, scout and sancho. the development and mortality of juveniles and the life-span, age-specific fecundity and survivorship of adult aphids were recorded and used to construct life tables. the juvenile development period (from birth to adulthood) was longest at 11.9 degrees c (16.8 days on cv. scout and 16.2 days on cv. sancho) and shortest at 26.7 degrees c (8.5 days on ... | 2001 | 11228587 |
| spiroplasma symbiont of the pea aphid, acyrthosiphon pisum (insecta: homoptera). | from a laboratory strain of the pea aphid, acyrthosiphon pisum, we discovered a previously unknown facultative endosymbiotic bacterium. molecular phylogenetic analysis based on 16s ribosomal dna revealed that the bacterium is a member of the genus spiroplasma. the spiroplasma organism showed stable vertical transmission through successive generations of the host. injection of hemolymph from infected insects into uninfected insects established a stable infection in the recipients. the spiroplasma ... | 2001 | 11229923 |
| independent origins and horizontal transfer of bacterial symbionts of aphids. | many insect groups have obligate associations with primary endosymbionts: mutualistic bacteria that are maternally transmitted and derived from an ancient infection. often, the same insects are hosts to 'secondary' bacterial symbionts which are maternally transmitted but relatively labile within host lineages. to explore the dynamics of secondary symbiont associations in aphids, we characterized bacteria infecting 15 species of macrosiphine aphids using dna sequencing, diagnostic polymerase chai ... | 2001 | 11251800 |
| glutathione s-transferases of aulacorthum solani and acyrthosiphon pisum: partial purification and characterization. | glutathione s-transferases (gst) play an important role in the detoxification of many substances including allelochemicals from plants. brassicaceae plants contain glucosinolates and emit volatile isothiocyanates which affect the gst system. a comparison of the gst of two aphid species, the generalist aulacorthum solani found on brassicaceae and the fabaceae specialist acyrthosiphon pisum, was made to try to explain their respective feeding behaviour. differences of gst were determined among the ... | 2001 | 11337260 |
| an aphid-borne bacterium allied to the secondary symbionts of whitefly. | bacterial 16s rdna amplified by pcr from the pea aphid acyrthosiphon pisum included a sequence with >98% similarity to secondary symbionts in the whitefly bemisia tabaci. the 'pea aphid bemisia-like bacterium' (pabs) and b. tabaci secondary symbionts are estimated to have diverged 17-34 million years ago, a time considerably more recent than the common ancestor of aphids and whitefly and suggestive of horizontal transmission of this bacterial lineage. pabs was scored in both the gut and ovaries ... | 2001 | 11377772 |
| why short-term bioassays are not meaningful--effects of a pesticide (imidacloprid) and a metal (cadmium) on pea aphids (acyrthosiphon pisum harris). | the life-table study on effects of a heavy metal, cd (100 and 200 mg kg-1 soil), and an insecticide, imidacloprid (4 and 40 g a.i. ha-1), on pea aphids revealed significant effects of both chemicals on life history traits and population dynamics. substantial differences in the action of the two chemicals and between the two doses of imidacloprid were observed. the pesticide caused high mortality at the beginning of the experiment, however some aphids were able to live for as long as control inse ... | 2001 | 11383475 |
| rickettsia associated with male-killing in a buprestid beetle. | many populations of the buprestid leaf-mining beetle, brachys tessellatus, from central south carolina, usa, show highly skewed sex ratios, ranging from 1.3 to 6.0 females per male. we have identified a rickettsia bacterium that is associated with sex ratio distortion (srd) and selective killing of male embryos in b. tessellatus. molecular assays of infection by this bacterium are highly associated with srd within families, and treatment with an antibiotic (tetracycline) increases the number of ... | 2001 | 11520350 |
| genetic linkage of ecological specialization and reproductive isolation in pea aphids. | the evolution of ecological specialization generates biological diversity and may lead to speciation. genetic architecture can either speed or retard this process. if resource use and mate choice have a common genetic basis through pleiotropy or close linkage, the resulting genetic correlations can promote the joint evolution of specialization and reproductive isolation, facilitating speciation. here we present a model of the role of genetic correlations in specialization and speciation, and tes ... | 2001 | 11528477 |
| clonal variation and covariation in aphid resistance to parasitoids and a pathogen. | the potential rate of evolution of resistance to natural enemies depends on the genetic variation present in the population and any trade-offs between resistance and other components of fitness. we measured clonal variation and covariation in pea aphids (acyrthosiphon pisum) for resistance to two parasitoid species (aphidius ervi and a. eadyi) and a fungal pathogen (erynia neoaphidis). we found significant clonal variation in resistance to all three natural enemies. we tested the hypothesis that ... | 2001 | 11681735 |
| comparison of complete nucleotide sequences of genomic rnas of four soybean dwarf virus strains that differ in their vector specificity and symptom production. | soybean dwarf virus (sbdv) is divided into four strains, namely ys, yp, ds and dp. ys and yp cause yellowing in soybeans, while ds and dp cause dwarfing. ys and ds are transmitted by aulacorthum solani, while yp and dp are transmitted by acyrthosiphon pisum. to clarify the taxonomic relationship between the four strains and to classify sbdv into an appropriate genus in the luteoviridae, we determined the complete nucleotide sequences of genomic rnas of four isolates belonging to each of the stra ... | 2001 | 11722012 |
| an experimental validation of orphan genes of buchnera, a symbiont of aphids. | although buchnera sp. aps, an intracellular symbiont of pea aphids, is a close relative of escherichia coli, its genome has been extensively modified because of its prolonged intracellular life. in our previous studies on the buchnera genome, computer analysis predicted three "orphan" genes, yba2, yba3, and yba4, which are open reading frames (orfs) with no homologs in the database. in this paper, we successfully validated all these orphan genes by rt-pcr and northern hybridization. the present ... | 2002 | 11890702 |
| estimating population size and transmission bottlenecks in maternally transmitted endosymbiotic bacteria. | many species of bacterial endosymbionts are acquired by animal hosts before birth, through direct transmission from mothers to eggs or embryos. this vertical transmission imposes a reduction in numbers or "bottleneck," and the size of this bottleneck affects the population structure and evolution of symbiotic lineages. we have estimated the size of the transmission bottleneck in buchnera, the bacterial symbiont of aphids, using basic light and electron microscopy techniques. by serial-sectioning ... | 2002 | 12087426 |
| influence of temperature on pea aphid acyrthosiphon pisum (hemiptera: aphididae) resistance to natural enemy attack. | the ability to resist or avoid natural enemy attack is a critically important insect life history trait, yet little is understood of how these traits may be affected by temperature. this study investigated how different genotypes of the pea aphid acyrthosiphon pisum harris, a pest of leguminous crops, varied in resistance to three different natural enemies (a fungal pathogen, two species of parasitoid wasp and a coccinellid beetle), and whether expression of resistance was influenced by temperat ... | 2002 | 12191444 |
| diversity and geographic distribution of secondary endosymbiotic bacteria in natural populations of the pea aphid, acyrthosiphon pisum. | in addition to the essential intracellular symbiotic bacterium buchnera, several facultative endosymbiotic bacteria called collectively secondary symbionts (s-symbionts) have been identified from the pea aphid acyrthosiphon pisum. we conducted an extensive and systematic survey of s-symbionts in japanese local populations of a. pisum using a specific pcr detection technique. five s-symbionts of a. pisum, pass, paus, pabs, rickettsia and spiroplasma, and two facultative endosymbionts universally ... | 2002 | 12296954 |
| a sex-linked locus controls wing polymorphism in males of the pea aphid, acyrthosiphon pisum (harris). | discrete variation in wing morphology is a very common phenomenon in insects and has been used extensively in the past 50 years as a model to study the ecology and evolution of dispersal. wing morph determination can be purely genetic, purely environmental, or some combination of the two. the precise genetic determinants of genetically based wing morph variation are unknown. here we explore the genetic basis of wing polymorphism in the pea aphid, which can produce either winged or wingless males ... | 2002 | 12399992 |
| plant-to-plant communication mediating in-flight orientation of aphidius ervi. | broad bean plants (viciafaba) infested by the pea aphid, acyrthosiphonpisum, play akey role in the in-flightorientation of the parasitoidaphidius ervi, by producing host-induced synomones (his). these volatiles are herbivore-specific and are systemically released from insect-free parts of an infested plant, suggesting the existence of an elicitor circulating throughout the plant. this study was designed to investigate whether the plant metabolic changes, leading to his biosynthesis and emission, ... | 2002 | 12449500 |
| erwinia aphidicola, a new species isolated from pea aphid, acyrthosiphon pisum. | five strains of gram-negative, oxidase-negative, facultatively anaerobic, fermentative, motile, rod-shaped bacterium with the general characteristics of the family enterobacteriaceae were isolated from the gut of multiple specimens of the pea aphid. all the strains caused aphid mortality when ingested by insects via a synthetic diet. the results of biochemical tests showed that these strains are most related to erwinia herbicola and pantoea agglomerans. according to dna-dna hybridization, the fi ... | 1997 | 12501306 |