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S B Vinson

Publications and source records attributed to S B Vinson.

At least 19 recordsLinked to original sources
PubMed2005

Host regulation and release of parasitism-specific proteins in the system Toxoneuron nigriceps-Heliothis virescens.

The braconid wasp Toxoneuron nigriceps induced qualitative and quantitative changes in the protein composition of the moth Heliothis virescens host hemolymph. Total protein concentration was found to be higher in parasitized host 4 days after parasitism as compared to control hosts, mainly due to changes in a particular group of proteins. Host proteins with a molecular mass of 173 and 72 kDa were found in higher levels in the hemolymph of parasitized larvae as control hosts approached pupation, while an 80 kDa peptide was found in reduced concentration in the hemolymph of parasitized hosts. Levels of these three peptides were maintained throughout parasitoid development, while two of them (173 and 72 kDa) were cleared from the host hemolymph close to pupation. Besides the regulation of host proteins, three parasitism-specific proteins (PSPs) were released into the host hemolymph. Two of them (PSP1-MW=116 kDa, pI=6.3; PSP2-MW=114 kDa, pI=6.2) first appeared in the hemolymph of parasitized hosts soon after pupation of control host and increased in concentration as the parasitoid developed. The third PSP (PSP3-MW=56 kDa, pI=5.8) was produced towards the end of parasitoid larval development, close to parasitoid egression. Database searches based on the amino acid composition and amino terminal sequence of PSP1 and PSP2 did not produce any significant matches, while PSP3 was identified as a putative chitinase. Incubation of host derived tissues, parasitoid larvae and teratocytes in 35S conditioned media suggested PSPs were a product of teratocytes. The role of the regulation of host proteins and release of PSPs by teratocytes for the successful development of T. nigriceps are discussed.

Amino Acid Sequence↗
PubMed2004

Differential gene expression during wing morph differentiation of the ectoparasitoid Melittobia digitata (Hym., Eulophidae).

Melittobia digitata is an ectoparasitoid of solitary bees and wasps that displays a trade-off between reproduction and dispersion through the development of two wing morphs (long and short wing morphs (LWM and SWM)). The morph differentiation of this species is an exceptional adaptation to maximize host exploitation and habitat colonization, and an understanding of the mechanisms underlying this developmental process will shed light on how nutrients or environmental elicitors alter regulatory pathways leading to physiological and metabolic changes resulting in such drastic developmental rearrangements. Here we describe the differential gene expression between SWM and LWM larvae of M. digitata in order to unravel the molecular mechanisms controlling the morph differentiation in this minute parasitoid and pinpoint the pathways involved in the regulation of this developmental process. The suppression subtractive hybridization (SSH) methodology was used to isolate differentially expressed genes using mRNA populations collected soon after morph development commitment. Dot blot analysis of 384 clones from a forward SSH library identified approximately 200 differentially expressed clones, including those transcripts present in very low abundance. Further DNA sequence analysis of a sub-population of 42 clones revealed 31 putatively unique transcripts, from which 5 were further analyzed by Northern blot analysis and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). The complete cDNA of one of these transcripts, a putative metalloprotease, was fully sequenced and is described. The role of the putative differentially expressed genes during the wing morph differentiation of M. digitata is discussed.

Amino Acid Sequence↗
PubMed2000

Estimating parasitoid immature mortality by comparing oviposition and pupal development of Trichogramma galloi Zucchi and T. pretiosum Riley on natural and factitious hosts.

Mortality during the immature development of T. galloi and T. pretiosum was estimated on UV-killed and live eggs of a factitious and a natural host, respectively. A staining technique was used to determine the actual parasitization of UV-treated eggs and was compared with the number of parasitoids that emerged per host egg (detectable parasitization). Effects of temperature as a factor of mortality during the immature development of both parasitoids on the factitious host was also assessed. The actual and detectable parasitization of live hosts was measured by recording both the parasitization behavior and the number of eggs where a parasitoid developed successfully. Our data show that mortality during immature development of both parasitoids may occur in live eggs of the natural host. No such mortality was observed when parasitoids developed on UV-killed eggs of the factitious host. Possible causes of parasitoid immature mortality and the effects of using UV-treated eggs of factitious hosts in estimating the parasitism capacity of Trichogramma in field conditions are discussed.

Animals↗
PubMed1995

Diversity in cyclic sesquiterpene production by Gossypium hirsutum.

Major sesquiterpene components of oil of Texas Race Stock 810 of Gossypium hirsutum were alpha- and beta-selinene. This is the seventh cyclic terpene type found to date in this genus. Both alpha- and beta-selinene, along with aromadendrene, were found but only as minor components of extracts of several domestic cultivars of G. hirsutum.

Gossypium↗
PubMed1992

Susceptibility and behavioral response of red imported fire ant (Hymenoptera: Formicidae) to selected entomogenous nematodes (Rhabditida: Steinernematidae & Heterorhabditidae).

Pathogenicity of infective juveniles of selected Steinernema spp. and Heterorhabditis spp. toward developing and reproductive stages of the red imported fire ant, Solenopsis invicta Buren, was tested under laboratory conditions. At 10(3)-10(5) infective juveniles per Petri dish, mortality of reproductive larvae, pupae, and alates ranged from 28 to 100% at higher doses after 96 h at 23-25 degrees C. Steinernema carpocapsae All was the most consistent species tested; this nematode caused mortality of fire ant larvae, pupae, and alates of 82-94, 64-96, and 38-99%, respectively. Although not susceptible to nematode infection, worker ants vigorously preened nematodes from brood, alates, and themselves. In a field study, S. carpocapsae (5 x 10(6) and 2 x 10(6) drench, 2 x 10(6) infective juvenile infection) was applied to active fire ant mounds in 3.8-liter suspensions. Hydramethylnon (75 ml), a water drench, a water injection, and untreated fire ant mounds were marked and treated. Overall activity in mounds treated with nematodes of hydramethylnon ranged from 40 to 48%. Satellite mound activity accounted for 32-44% of overall activity in mounds treated with nematodes 2 wk after treatment. However, 6 wk after treatment, activity in mounds treated with hydramethylnon was 44%; activity of mounds treated with nematodes ranged from 52 to 80%. Satellite mound activity accounted for 0-24% of overall activity. Whereas a soil drench of S. carpocapsae showed potential as a control method for the red imported fire ant, colony relocation after nematode treatment could limit overall efficacy unless application techniques are developed to overcome or take advantage of the movement.

Animals↗
PubMed1991

Distribution and density of polygyne fire ants (Hymenoptera: Formicidae) in Texas.

Multiple-queen or "polygyne" Solenopsis invicta Buren colonies are a serious economic and environmental concern because they occur in much higher densities than the monogyne form. Polygyne colonies have been found at numerous locations in the United States; nevertheless, the frequency and distribution of this form are poorly known. Almost 700 roadside sites in 168 Texas counties were surveyed. Polygyny was discovered at 54% of the infested sites. Polygyne populations were scattered in a mosaic across Texas. The frequency of polygyny varied somewhat with geographic region, but the pattern was generally unrelated to habitat and environmental conditions. Polygyne sites averaged more than twice as many mounds per hectare as monogyne sites. Populations of monogyne and polygyne forms were slightly lower in cooler and drier portions of the state. Mounds of both forms were about the same size. Polygyny was correlated with lower rates of sexual production and reduced numbers of native ants. The high frequency of polygyny in Texas indicates that the fire ant problem in the state is much greater than previously realized.

Analysis of Variance↗
PubMed1988

Interference with function of plasmatocytes of Heliothis virescens in vivo by calyx fluid of the parasitoid Campoletis sonorensis.

Immature stages of the ichneumonid parasitoid, Campoletis sonorensis, develop within the haemocoel of its noctuid host, Heliothis virescens. The host cannot encapsulate the parasitoid egg owing to the suppressive effect of the polydnavirus-laden calyx fluid injected by the female parasitoid during oviposition. We have examined the effects of injection of calyx fluid on the following haemocytic manifestations of the immune system of 5th-instar larvae of H. virescens: encapsulation, nodulation, phagocytosis, erythrocyte rosetting and coagulation. Of these phenomena, only those requiring the formation of a multicellular sheath of plasmatocytes were affected. In general, encapsulation was fully suppressed; all of the C. sonorensis eggs and most of the glass rods implanted as targets were devoid of attached haemocytes 3 days after implantation although a few of the latter were coated by a sparsely distributed layer of granulocytes. Plasmatocytes also appeared to be present in thicker depositions of haemocytes. In nodulation, only the second, encapsulation-like phase was inhibited. The resistant first stage, involving the entrapment of particles by haemocytes, only resulted in the formation of amorphous, disorganized nodules. Granulocyte-dependent aspects of the immune system (phagocytosis, rosetting and possibly coagulation and the first stage of encapsulation and nodulation) occurred normally. The data suggest that in 5th-instar hosts injection of calyx fluid acts specifically on plasmatocyte function.

Animals↗
PubMed1988

Preliminary characterization and purification of in vitro encapsulation promoting factor: a peptide that mediates insect haemocyte adhesion.

The granular cells and plasmatocytes (PLs) of Heliothis virescens form multicellular aggregations in vitro. This allows capsules to form around suitable targets. Prior trypsinization of the haemocytes abolishes their ability to encapsulate, and this function can be restored by adding plasma to the trypsinized cells. Trypsinized PLs were also unable to spread on a planar glass surface unless normal plasma was present. Plasma was subjected to a variety of treatments to determine the nature of the encapsulation promoting factor (EPF) using the in vitro encapsulation system as a bioassay. The data suggest EPF is a peptide; it is trypsin sensitive and moderately heat stable. Similar results were obtained when using spreading by trypsinized PLs as the bioassay. Dialysis using a 3,500 MW cut-off membrane also abolished encapsulation promoting activity. Protein-free extracts of plasma (crude EPF) has strong activity in both bioassays but does not agglutinate human erythrocytes. A single peak with strong activity in both bioassays was resolved after subjecting crude EPF to reversed-phase HPLC. This active material was purified after additional HPLC with a different solvent system.

Animals↗
PubMed1986

Identification, Mapping, and In Vitro Translation of Campoletis sonorensis Virus mRNAs from Parasitized Heliothis virescens Larvae.

Expression of Campoletis sonorensis virus (CsV) in parasitized Heliothis virescens larvae was investigated by Northern blot analysis of poly(A)(+) mRNAs isolated from H. virescens larvae at various times after parasitization by C. sonorensis. At least 12 CsV mRNAs were detected in parasitized H. virescens larvae. Injection of nonparasitized H. virescens larvae with purified CsV resulted in a pattern of viral mRNAs similar to that observed in naturally parasitized larvae. With CsV DNA restriction fragments which contained expressed sequences, individual CsV mRNAs were mapped to the superhelical DNAs of the viral genome. Two gene-specific probes, which consisted of cloned S1 nuclease-protected restriction fragments, each hybridized to several CsV superhelical DNAs, suggesting that some CsV genes may be shared on several superhelical DNAs. Cloned restriction fragments containing sequences which flank the expressed sequences also hybridized to numerous CsV superhelical DNAs. Some CsV proteins were identified by in vitro translation of hybrid-selected CsV mRNAs.

Journal Article↗
PubMed1986

Analogous recognition of phospholipids by insect phagocytes and mammalian macrophages.

Phagocytic cells from larvae of the moth Heliothis virescens and peritoneal macrophages of mice were observed to preferentially bind negatively charged phospholipid vesicles containing phosphatidylglycerol or phosphatidylserine as compared to neutral or positively charged vesicles. Since phagocytes have retained their primitive function of endocytosis throughout evolution, the recognition of negatively charged phospholipids may be a primitive mechanism for the identification of potential targets by macrophages.

Animals↗
PubMed1983

Correlating the initiation of virus replication with a specific pupal developmental phase of an ichneumonid parasitoid.

The morphogenesis of virus particles associated with the calyx region of the lateral oviduct of the ichneumonid parasitoid Campoletis sonorensis is initiated during a specific phase of pupal development. The extent of body pigmentation proved to be the most reliable visual marker for correlation of induction of virus replication with particular phases of pupal development. Parasitoids removed from their pupal cases at 15 and 16 days after egg deposition were categorized into one of four developmental groups based on the degree of pigmentation. Viruses were not evident in the calyx cells of pupae representing the initial developmental stage, however, in all subsequent stages the concentration of particles gradually increased as development progressed. Observations of freeze-fractured tissue support previous suppositions that the viruses bud through the nuclear envelope following synthesis de novo within the nucleus.

Animals↗
PubMed1983

Fire ant venom hypersensitivity. I. Comparison of fire ant venom and whole body extract in the diagnosis of fire ant allergy.

Levels of IgE antibody to fire ant whole body extract (FA-WBE) and fire ant venom (FAV) were evaluated in 60 patients with clinical histories of fire ant sting hypersensitivity and 11 frequently stung individuals without significant clinical reactivity to fire ant. An overlap of levels of IgE antibody to FA-WBE and FAV was seen between groups of patients with increasingly severe clinical reactivity; however, the group mean IgE antibody level of patients without significant clinical reactivity differed markedly from the group means of patients with more severe clinical reactivity (p less than 0.001). In 31 patients a good correlation (r = 0.6935) was found comparing FA-WBE IgE antibody level with FA-WBE skin tests, and in 26 patients a good correlation (r = 0.8564) was obtained comparing FAV IgE antibody levels with FAV skin tests. An excellent Spearman rank correlation coefficient (r = 0.9197) was found on comparison of FAV and FA-WBE IgE antibody levels in 71 individuals. Cross-reactivity of FAV and FA-WBE was demonstrated by the ability of these reagents to competitively inhibit the binding of IgE antibody to solid-phase FA-WBE and FAV in the radioallergosorbent test (RAST). From these results we conclude that FAV and FA-WBE both contain relevant allergens important in fire ant-allergic individuals and that skin tests and RAST are both valid as diagnostic tests for fire ant allergy. Finally, there is a good correlation between RAST and skin tests using FA-WBE or FAV as test reagents, since these reagents are highly cross-reactive as demonstrated by their ability to inhibit each other in the RAST.

Adolescent↗
PubMed1983

Expression of Campoletis sonorensis Virus in the Parasitized Host, Heliothis virescens.

Polyadenylated mRNA transcripts of the virus of Campoletis sonorensis were detected in Heliothis virescens host larvae 2 h after the larvae had been parasitized by C. sonorensis females and continued to be present in host larvae through 9 days postparasitization while C. sonorensis developed endoparasitically. cDNAs of viral transcripts present in H. virescens hybridized with only certain C. sonorensis viral DNAs.

Journal Article↗
PubMed1982

Venom apparatus of braconid wasps: comparative ultrastructure of reservoirs and gland filaments.

Two types of venom apparatus present in female braconid wasp were examined in nine species and compared ultrastructurally. The reservoir of type 1 venom apparatus has a relatively thick muscular sheath which is innervated, while the longitudinal and circular muscles of the type 2 reservoir consist of scattered fibers which are not innervated. The intima of the reservoir of type 1 venom apparatus is unevenly thickened. In contrast, the reservoir of type 2 venom apparatus has a relatively thinner and more uniform intima. The gland filaments of both types of venom apparatus are ultrastructurally similar. Distinct particles found in the venom apparatus of two of the nine species are described.

Animals↗
PubMed1982

Virus with a Multipartite Superhelical DNA Genome from the Ichneumonid Parasitoid Campoletis sonorensis.

Virus was isolated from the lumen of the calyx region of ovaries in the parasitoid wasp Campoletis sonorensis (Hymenoptera: Ichneumonidae), and the nature of the viral DNA was analyzed. DNA purified from a homogeneous band of virus contained double-stranded superhelical molecules which were polydisperse in molecular weight. At least 25 different covalently closed circles were present, ranging in molecular weight from 4.0 x 10(6) to 13.6 x 10(6). The virus DNA was analyzed with restriction enzymes, and the nature of the genetic complexity was evaluated by Southern blot hybridization of native superhelical and relaxed circular virus DNA and of SalI- and HindIII-digested DNA. The data suggest that most of the variously sized covalently closed DNAs were composed primarily of nonhomologous sequences. The different size classes of covalently closed viral DNAs did not appear to exist in equimolar concentrations. However, there was no evidence from observation of virus particles in the electron microscope or from virus fractionation experiments that a mixture of viruses was present in the calyx fluid. The results from this study suggest' that the virus isolated from C. sonorensis, like those isolated from other endoparasitic hymenoptera, may belong to a new class of DNA viruses in which the genome is multipartite, with each DNA existing as a superhelical molecule.

Journal Article↗
PubMed1982

A histochemical and X-ray microanalysis study of calcium changes in insect flight muscle degeneration in Solenopsis, the queen fire ant.

Potassium pyroantimonate histochemistry, coupled with ethyleneglycoltetraacetic acid (EGTA)-chelation and X-ray microprobe analysis, was employed to localize intracellular calcium binding sites in the normal and degenerating flight musculature in queens of Solenopsis, the fire ant. In normal animals, calcium distribution was light to moderate within myofibrils and mitochondria. In the early contracture stages of the insemination-induced degeneration, both myofilament and mitochondrial calcium loading was markedly increased. In the terminal stages of myofibril breakdown, only Z-lines (isolated or in clusters) with an associated filamentous residue persisted. These complexes were also intensely calcium positive. This study further documents the presence of increased sarcoplasmic calcium during muscle necrosis. Surface membrane defects, mitochondrial calcium overload, and calcium-activated proteases may all be involved in this "normal" breakdown process.

Animals↗