Failure of intramuscular antivenom in Red‐back spider envenoming

Four cases of Red‐back spider envenoming are reported in which there was minimal response to intramuscular antivenom. Intravenous antivenom was then administered in each case with almost complete resolution of symptoms. All cases were followed up to confirm the effect of treatment. This failure of intramuscular Red‐back antivenom raises the question of its efficacy. There has been no controlled trial to prove that intramuscular Red‐back antivenom is effective and animal work with other antivenoms has demonstrated the intramuscular formulation to have delayed and incomplete effects. Controlled studies should be undertaken to establish the effectiveness of intravenous and intramuscular Red‐back antivenom.     

木地板中裸蛛甲的防制研究

目的了解木地板、木制品害虫情况,探索木地板裸蛛甲防制方法.方法现场调查,采集害虫标本,并进行分析鉴定.采用雾化喷洒、热烟雾剂及粉杀法等3种方法杀虫.结果调查发现危害木地板、木制品的害虫为裸蛛甲.雾化喷洒、热烟雾剂及粉杀法3种方法综合进行,有效控制了家居木地板、木制品害虫的危害.结论防制木地板、木制品害虫的首要工作是预防,若发现虫害应及时采取有效措施杀灭、控制虫害.     

Fine structure of the anteromedial eye of the liphistiid spider,Heptathela kimurai

Background: The presence of efferent fibers in the anteromedial eye of liphistiid spiders kept in natural daily cycles of illuminance has been reported. However, this report is limited to innervation by the efferent fiber and daily rhabdomal changes, and there have been no detailed ultrastructural accounts of the eye. Methods: The fine structure of this eye was examined by electron microscopy. Results and conclusions: The eye consists of a cornea, a lens, a vitreous body, and a retina. The retina contains 13 or 14 receptor cells and glial cells. The rhabdoms are distal to the nuclei of the receptor cells. In the distal region of the receptive segment, the rhabdomeres lie in the center of the cell. In the middle region, anisomorphic rhabdoms formed by microvilli from adjacent cells are at the cell periphery. In the proximal region, the rhabdomeres are situated in the center of the cell. The ocellar nerve of the eye runs toward the protocerebrum and enters the posterior part of the first optic ganglion of the secondary eyes. Pigmented cells and nonpigmented cells are observed. The pigmented cells are located in the most lateral of the eye and cover the whole eye. The nonpigmented cells are located in the receptor cell bodies and extend to the origin of the ocellar nerve. They wind to form capillaries filled with electron-dense material. These structures are discussed in comparison with those of other spiders and other chelicerates. © 1994 Wiley-Liss, Inc.     

Gastrulation in the spider Zygiella x-notata involves three distinct phases of cell internalization.

The cell movements of gastrulation were analyzed in embryos of the spider Zygiella x-notata, using time-lapse video, cell tracing, and improved histology. Cells are internalized near the center of the germ disc in three distinct phases. First, cumulus mesenchyme cells ingress and migrate as a group beneath the superficial layer. Second, mass internalization through a blastopore yields a diffusely organized deep layer. Third, superficial cells accumulate at the center of the germ disc to form the caudal bud. The floor is internalized, and the caudal bud moves over the nascent dorsal field to form the caudal lobe. This pattern of gastrulation differs from the canonical pattern described in the historical literature: (1) the cumulus of Z. x-notata is completely formed before any other cells internalize; and (2) the caudal lobe is formed by means of the caudal bud, which is a locus of cell internalization.     

Effect of Loxosceles gaucho venom on cell morphology and behaviour in vitro in the presence and absence of sphingomyelin.

This study was performed to investigate whether the toxic effects of Loxosceles gaucho venom on cells might be exerted via stimulators of TNF-alpha release generated by sphingomyelinase D--a major component of the venom. It was demonstrated that L. gaucho venom alone is unable to induce TNF-alpha release by J774A.1 cells, while in the presence of exogenous sphingomyelin it induces a high level of TNF-alpha release which is significantly increased by incubation with non-inactivated serum. Ceramide phosphate also induces TNF-alpha release in J774A.1 cells, but (unlike sphingomyelin/sphingomyelinase) the level of release is not influenced by the presence or otherwise of non-inactivated serum. L. gaucho venom does not induce proliferation of J774A.1 cells and even at high concentrations it does not affect their viability. J774A.1 cells, which prior to venom treatment were elongated and clumped, round up after venom treatment, but, revert to their original morphology after incubation with fresh medium. TNF-alpha resistant MRC-5 cells and TNF-alpha sensitive MCF-7 cells are susceptible to the toxic effect of both L. gaucho venom and ceramide phosphate. The results obtained in this study demonstrate that exogenous sphingomyelin can modulate, in vitro, the release of TNF-alpha induced by L. gaucho venom in mouse macrophages. In addition, the results also indicate that ceramide phosphate and L. gaucho venom are toxic to several different cell types, via a variety of mechanisms, some, but not all, of which may involve TNF-alpha as an intermediary.     

The Cystine Knot Is Responsible for the Exceptional Stability of the Insecticidal Spider Toxin ω-Hexatoxin-Hv1a

The inhibitor cystine knot (ICK) is an unusual three-disulfide architecture in which one of the disulfide bonds bisects a loop formed by the two other disulfide bridges and the intervening sections of the protein backbone. Peptides containing an ICK motif are frequently considered to have high levels of thermal, chemical and enzymatic stability due to cross-bracing provided by the disulfide bonds. Experimental studies supporting this contention are rare, in particular for spider-venom toxins, which represent the largest diversity of ICK peptides. We used ω-hexatoxin-Hv1a (Hv1a), an insecticidal toxin from the deadly Australian funnel-web spider, as a model system to examine the contribution of the cystine knot to the stability of ICK peptides. We show that Hv1a is highly stable when subjected to temperatures up to 75 °C, pH values as low as 1, and various organic solvents. Moreover, Hv1a was highly resistant to digestion by proteinase K and when incubated in insect hemolymph and human plasma. We demonstrate that the ICK motif is essential for the remarkable stability of Hv1a, with the peptide’s stability being dramatically reduced when the disulfide bonds are eliminated. Thus, this study demonstrates that the ICK motif significantly enhances the chemical and thermal stability of spider-venom peptides and provides them with a high level of protease resistance. This study also provides guidance to the conditions under which Hv1a could be stored and deployed as a bioinsecticide.