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At least 649 records · Page 36Linked to original sources

PubMed1983

Toxic and reproductive effects of the soluble organic fraction from diesel particulate emissions on the parasitoid wasp, Bracon hebetor.

The soluble organic fraction of diesel particulate emissions was tested for physiological and genotoxic effects on the parasitoid wasp, Bracon hebetor. Adult female survival after topical treatment was significantly decreased at the higher concentrations of SOF. Daily egg production, a sensitive assay for genotoxic and physiological effects, was not significantly affected at any concentration. Egg hatchability on Days 1-5, representing vitellogenic oocytes at the time of treatment, was decreased, but this effect lacked consistency and dose dependence. An extensive dominant lethal test was performed with negative results. Possible explanations for these findings and comparisons with in vitro tests such as the Ames test and sister chromatid exchange are discussed.

Animals↗

PubMed1983

Conformational change of mastoparan from wasp venom on binding with phospholipid membrane.

The conformational change upon binding with phospholipid membrane has been studied of mastoparan from wasp venom, a tetradecapeptide causing the degranulation of mast cells. The 270-MHz 1H-NMR spectra and CD spectra indicate that the mastoparan molecule takes the alpha-helical conformation in methanol solution, but a much less ordered form in aqueous solution. On binding with phospholipid membrane, the alpha-helical conformation is formed even in aqueous medium. Such a conformational change is primarily due to the interaction between the aliphatic side chains of mastoparan and the hydrophobic interior of phospholipid membrane, in contrast to the case of melittin from bee venom.

Bee Venoms↗

PubMed1985

A wasp venom mastoparan-induced polyphosphoinositide breakdown in rat peritoneal mast cells.

The phospholipid metabolism of rat peritoneal mast cells stimulated with mastoparan, a secretagogue purified from wasp venom, was investigated. Mastoparan at 20 micrograms/ml caused a rapid secretion of histamine. Mastoparan induced a transient decrease of phosphatidylinositol 4,5-biphosphate on 32P labeling and generation of a water-soluble degradation product, inositol trisphosphate on [3H]inositol labeling, suggesting the activation of phospholipase C upon stimulation.

Animals↗

PubMed1990

Mastoparan, a peptide toxin from wasp venom, stimulates glycogenolysis mediated by an increase of the cytosolic free Ca2+ concentration but not by an increase of cAMP in rat hepatocytes.

A wasp venom, mastoparan, rapidly increased the cytosolic free Ca2+ concentration [( Ca2+]i) and activated phosphorylase in rat hepatocytes in a concentration-dependent manner. Mastoparan could increase [Ca2+]i even in the absence of extracellular Ca2+, but a larger increase was observed in the presence of extracellular Ca2+. Thus, mastoparan mobilized Ca2+ from intracellular and extracellular Ca2+ stores. It also activated inositol triphosphate (IP3) accumulation, but did not stimulate cAMP production. From these results, we conclude that mastoparan activates rat hepatic glycogenolysis mediated by the accumulation of IP3, which causes an increase of [Ca2+]i but not that mediated by cAMP.

Adenylyl Cyclases↗

PubMed1992

Activation of nucleoside diphosphate kinase by mastoparan, a peptide isolated from wasp venom.

We have previously reported that GDP-bound alpha beta gamma-trimeric GTP-binding (G) proteins can be converted into the active GTP-bound form with nucleoside diphosphate (NDP) kinase and ATP, although its exact activation mechanism still remains to be resolved. In the present study, we investigated whether NDP kinase activity was modified by mastoparan, a wasp venom peptide that is known to activate G proteins as an agonist-receptor complex. The activity of NDP kinase measured by the formation of GTP from ATP and GDP was markedly stimulated, when the kinase was incubated with mastoparan. The concentration of mastoparan required for the activation was much lower than that observed for the peptide-induced activation of G proteins under similar assay conditions. There was also an increase in the phosphorylated intermediate of NDP kinase as well as the catalytic activity upon its incubation with mastoparan. These results suggest that mastoparan not only activates G proteins directly via guanine nucleotide exchange reaction but also stimulates NDP kinase activity.

Animals↗

PubMed1985

Reproductive performance and mutagenic response of the wasp Bracon hebetor following treatment with the antibiotic bleomycin.

Bleomycin (BM) induced dominant-lethal genetic lesions in the gametes of both sexes of adult Bracon hebetor wasps following ingestion. This effect was demonstrated by decreased fertility in the unfertilized eggs of treated females as well as in eggs fertilized by mature sperm derived from treated males. Death in the unhatched eggs occurred prior to blastoderm formation indicating BM caused chromosome breakage. Affected ovarian cells were limited to those exposed to BM between the developmental stages of vitellogenesis and early metaphase I. Sperm-associated fertility reductions were temporary in duration with substantial reductions being observed starting on the second day following the initiation of oviposition. BM lowered general egg-formation capacity in treated females but, unlike the fertility effects, decreased fecundity was caused by somatic debility. Although the BM-induced genetic damage observed in B. hebetor was radiomimetic in nature, the time of appearance and duration of the effects did not correspond with previous patterns found when B. hebetor adults were exposed to X-rays. While the differences could be due to the BM detoxification or the repair of BM-induced chromosome damage, further investigation would be required to demonstrate the presence of such systems in this hymemopteran.

Animals↗

PubMed1991

Neurotoxic kinins from wasp and ant venoms.

Kinins are polypeptides of 9-18 amino-acid residues containing a bradykinin-like sequence, in some cases as part of a molecule. The bradykinin-like sequence is either bradykinin, Hyp3-bradykinin or Thr6-bradykinin. Kinins are neurotoxic components of wasp and ant venoms, causing in the insect CNS a presynaptic block of the cholinergic transmission by means of an irreversible depletion, probably caused by a non-competitive inhibition of choline uptake.

Amino Acid Sequence↗

PubMed1985

Antigenic cross-reactivity of venom proteins from hornets, wasps, and yellow jackets.

The venoms of hornets, wasps, and yellow jackets have similar protein compositions. The three major venom proteins are antigen 5, hyaluronidase, and phospholipase A1. These proteins, which are allergens in man, have been isolated and compared for their biochemical and antigenic properties. The homologous proteins from these vespids have very similar biochemical properties that include their molecular size and charge, their amino acid composition, and, where it is applicable, their enzymatic activities. They were studied for their antigenic cross-reactivity with specific mouse antibodies. The phospholipases demonstrated no detectable antigenic cross-reactivity, whereas the antigen 5s and hyaluronidases demonstrated varying extents of cross-reactivity.

Amino Acids↗

PubMed1988

Allergens in Hymenoptera venom. XXI. Cross-reactivity and multiple reactivity between fire ant venom and bee and wasp venoms.

The relationships between fire ant venom and bee and wasp venoms were explored by studying sera from five groups of subjects. Group 1 included adults not allergic to any venoms and who were not exposed to fire ants. Group 2 included adults with fire ant exposure who were not allergic to venoms. Group 3 included patients with recent systemic reactions to fire ant venom. Group 4 included patients allergic to bee and vespid venoms with no fire ant exposure. Last, group 5 included patients allergic to bee and vespid venoms with fire ant exposure. None of the serum samples from group 1 was RAST reactive to fire ant venom, but 24% of those from group 2 were fire ant positive, as were 100% of those from group 3, 51% of those from group 4, and 87% of those from group 5. The RAST-positive patients in groups 2 and 5 were also skin test positive. RAST inhibition studies demonstrated cross-reactivity in some cases and multiple reactivity in others. The serum samples were further investigated via nondenaturing electrophoretic immunoblot studies and RAST with highly purified allergens. Serum samples from group 4 reacted to a single band on immunoblots and with only one of the four purified allergens from fire ant venom (Solenopsis invicta I, or Sol i I). Serum samples from groups 2, 3, and 5 showed various patterns of allergen reactivity. All serum samples from patients allergic to fire ant venom who also reacted to bee and/or vespid venoms by RAST contained IgE antibodies binding to Sol i I.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Expression of antimicrobial peptide genes after infection by parasitoid wasps in Drosophila.

We report here the use of a specific beta-galactosidase staining assay and Northern blotting technique to examine the expression of three genes encoding either antibacterial peptides (diptericin, cecropin A) or an antifungal peptide (drosomycin) in Drosophila following infection by larval and pupal parasitoids. The results show that the genes encoding these peptides are either not induced or minimally induced in wasp-infected hosts, but remain responsive and are induced upon microbial challenge. As the parasitoids elicit a cellular response, our data suggest that the antimicrobial responses are activated and/or regulated by mechanisms that are independent of those mediating cellular encapsulation.

Animals↗

PubMed1987

Immunochemical observations of antigen 5, a major venom allergen of hornets, yellowjackets and wasps.

Antigen 5 is a venom protein of hornets, yellowjackets and wasps, and it is an important allergen for insect-sensitive patients. Antigen 5s from these insects are found to have similar amino-terminal sequences for their first 20 residues, and to have similar cyanogen bromide cleavage patterns. A partial sequence homology of antigen 5s and scorpion neurotoxins is observed. Antigen 5s from these insects show varying extents of cross reactivity when tested with mouse polyclonal antibodies by enzyme immunoassay and they show limited or no cross reactivity with mouse monoclonal antibodies. Chemically modified antigen 5s shown greatly decreased binding of antigen 5-specific mouse polyclonal antibodies. The modified antigen 5s include its reduced and carboxymethylated

Amino Acid Sequence↗

PubMed1983

Characterization of two paralysing protein toxins (A-MTX and B-MTX), isolated from a homogenate of the wasp Microbracon hebetor (Say).

Two paralysing toxins (A-MTX and B-MTX) from extracts of Microbracon hebetor (Say) wasps were isolated and purified by gel chromatography, ion exchange chromatography and gel electrophoresis. Both toxins are labile proteins with molecular weights of 43,700 and 56,700, respectively, as estimated by gel chromatography, and with isoelectric pH of 6.85 and 6.62, respectively. Both toxins are inactivated by proteolytic enzymes and by dithiothreitol, but A-MTX appears to be more resistant than B-MTX. The relative amino acid compositions of both toxins show great similarity. The biological effects of the two toxins were identical to those previously found for crude toxin preparations.

Amino Acids↗

PubMed1996

Nuclear magnetic resonance microscopy of the development of the parasitoid wasp Venturia canescens within its host moth Plodia interpunctella.

Nuclear magnetic resonance microscopy was used to image the parasitoid wasp Venturia canescens (Hymenoptera: Ichneumonidae) within larval and pupal instars of its host, the Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae). The images were obtained using gradient-echo and chemical shift selective pulse sequences and clearly showed the location and shapes of the parasitoid as it developed from the L1 larva to a pupal stage within the host. The digestive, nervous, and tracheal systems of the host were identified and changes were observed as the host underwent metamorphosis. Destruction of the host tissues by the parasitoid was visible. It was found that the parasitoid first ate the fat body and digestive system of the host, allowing the host to continue to grow, and only progressed to the vital organs when its own development had neared pupation.

Animals↗

PubMed1983

Smooth muscle contracting compounds in venoms of sphecid wasps (Hym: Sphecidae).

1. The presence of smooth muscle contracting substances in venom preparations made from six species of sphecid wasps was investigated using a number of standard pharmacological techniques. 2. In addition, acetylcholine was identified by enzymatic degradation as well as by mass fragmentography, while histamine was determined using a radio-enzymatic method. 3. The venom reservoir of P. triangulum contains about 400 ng acetylcholine, but no histamine-, 5-HT- or bradykinin-like activity. 4. The venoms of the five other species contain histamine in amounts varying from 20 to 2000 ng per venom reservoir, but no acetylcholine-, 5-HT- or bradykinin-like activity.

Acetylcholine↗

PubMed1984

Ion channel block in rat diaphragm by the venom of the digger wasp Philanthus triangulum.

In the rat phrenic nerve-diaphragm preparation the twitch tension and tetanic contractions, already reduced by d-tubocurarine, succinylchloride or neostigmine, are further reduced by the venom of the digger wasp Philanthus triangulum F. The venom reduces the temperature- and voltage-sensitivity of the acetylcholine-receptor-activated ion channels, at the motor end-plate, and shortens the decay time of the miniature end-plate currents, analogous to a block described for the purified toxin, delta-PTX, on insect glutamate-activated channels. Preliminary results show that delta-PTX has an effect similar to that of the total venom on the decay phase of miniature end-plate currents.

Acetylcholine↗

PubMed1990

Threonine6-bradykinin in the venom of the wasp Colpa interrupta (F.) presynaptically blocks nicotinic synaptic transmission in the insect CNS.

1. The venom of the solitary scoliid wasp Colpa interrupta (F.) shows a kinin-activity, when tested on a cascade of mammalian smooth muscle preparations, and, in addition, a contraction of the rat colon. 2. The venom also irreversibly blocks the nicotinic synaptic transmission from the cercal nerve to a giant interneuron in the sixth abdominal ganglion of the cockroach, Periplaneta americana. 3. The same activities have been found within one HPLC fraction. 4. However, rechromatography of this fraction resulted in four subfractions being active on smooth muscles. 5. One fraction caused contraction of the colon, three other fractions contained kinin-activity. 6. Only the most active kinin fraction blocked synaptic transmission in the insect CNS. 7. This fraction contained threonine-bradykinin. 8. Synthetic Thr-bradykinin causes irreversible presynaptic activation-induced block of transmission in the insect CNS.

Amino Acid Sequence↗

PubMed1993

Presynaptic block of transmission in the insect cns by mono- and di-galactosyl analogues of vespulakinin 1, a wasp (Paravespula maculifrons) venom neurotoxin.

1. The pharmacological properties of four synthetic analogues of the wasp neurotoxin, Vespulakinin 1, were studied using a cascade of mammalian smooth muscle preparations and the synaptic transmission from the cockroach cercal nerves to a giant interneuron. 2. All analogues have an extremely slow bradykinin-like effect on the smooth muscles. The carbohydrate-free and the two mono-glycosylated analogues are about equally active with bradykinin. 3. The double glycosylated derivative is about 5 times more potent than bradykinin. 4. All analogues have two different effects on synaptic transmission in the insect CNS--at first a direct and reversible block of excitatory nicotinic transmission with a concurrent activation of the inhibitory GABA-ergic system and, secondly, a delayed irreversible block of the transmission, comparable to the block described earlier for bradykinin and Thr6-bradykinin. 5. For the synaptic transmission in the insect CNS the double glycosylated kinin is about 5 times more potent than bradykinin.

Amino Acid Sequence↗

PubMedDate not supplied

Myeloradiculopathy associated with wasp sting.

A 12-year-old girl developed a reversible myeloradiculopathy 1 week after a wasp sting. Delayed neurologic hypersensitivity reactions to Hymenopteran stings occur primarily in adults. Reactions involving both the peripheral and central nervous systems are extremely rare and have never been reported in a child. The mechanisms underlying this uncommon reaction may be related to age-dependent differences in immunologic responses.

Animals↗