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At least 703 records · Page 39Linked to original sources
PubMed2003

Purification and characterization of a neurotoxic peptide huwentoxin-III and a natural inactive mutant from the venom of the spider Selenocosmia huwena Wang (Ornithoctonus huwena Wang).

A novel neurotoxic peptide, named huwentoxin-III, and a natural mutant have been isolated from the venom of the spider Selenocosmia huwena Wang (Ornithoctonus huwena Wang). The average molecular weights of the two peptides were determined as 3853.35 and 3667.40 by mass spectrometry, respectively. Huwentoxin-III has 33 amino acid residues containing 6 cysteine residues. Its natural mutant is only truncated a tryptophan residue from C-terminals of huwentoxin-III. The sequences of the two peptides show 70.5% sequence similarity with that of lectin-like peptide SHL-I previously isolated from the venom of the same spider, while they cannot agglutinate human erythrocytes. Huwentoxin-III can reversibly paralyze cockroaches for several hours with an ED(50) of (192.95 +/- 120.84) microg/g (P=0.95) (mean +/- SD) and can enhance the muscular contractions elicited by stimulating the nerve of the isolated rat vas deferens, however, the mutant of huwentoxin-III has no such effect, which suggests that Trp33 was an important residue related to the biological function of huwentoxin-III.

Amino Acid Sequence↗
PubMed2004

Clinical course of a loxosceles spider bite in Turkey.

We report the first case from Turkey of a dermonecrotic wound associated with possible Loxosceles spider bite and offer the complete clinical course that resulted in a permanent scar. Emergency physicians in western Turkey should be aware of Loxosceles spider bites as a cause of necrotizing wounds.

Adult↗
PubMedDate not supplied

Brown recluse spider envenomation: dermatologic application of hyperbaric oxygen therapy.

Envenomation from the brown recluse (Loxosceles recluse) spider commonly proceed on one of three clinical pathways. The majority of bites (90%) result in nothing more than a local reaction. They are essentially self-limiting, require little if any attention, and resolve spontaneously. A great majority of the remaining bites will produce necrotic ulcerations of various sizes and dimensions, with systemic sequela ranging from fever to hemolysis and kidney failure. Finally, and in the most rare cases, the patient will succumb a fatal systemic reaction. Current therapeutic options for these wounds remain controversial and include the following: local care, corticosteroids, dapsone, and hyperbaric oxygen (HBO) therapy. This article will review the application of HBO therapy for patients who are envenomated by brown recluse spiders. Information for this manuscript was derived from multiple MEDLINE searches as well as searches of the National Baromedical Service's hyperbaric specialty literature collection.

Animals↗
PubMed1992

Latrodectism: bite of the black widow spider.

Latrodectism, the clinical syndrome that follows envenomation by the black widow spider, may easily be confused with more common conditions. Acute manifestations are characterized by agonizing pain and muscle spasm. Prolonged symptoms, primarily related to neurologic dysfunction, may occur. Familiarity with the manifestations of latrodectism is the key to diagnosis. Family physicians should consider latrodectism in patients presenting with severe pain and muscle cramps, particularly if the setting and history are consistent with a possible spider bite. Optimal therapy remains controversial. Early use of specific antivenin in severely envenomated patients may prevent the development of lingering symptoms, usually related to neurologic dysfunction.

Adult↗
PubMed1991

[Black widow spider bite in the Negev].

In the 4 years, 1985-88, 9 adults bitten by black widow spiders (Latrodectus inactopus) were hospitalized. The syndrome of lactrodectism, not as yet described from the Negev, was mainly characterized in these patients by restlessness, profuse perspiration, severe abdominal pain and rigidity, and muscular twitching. In addition, in 2 cases there was gastrointestinal involvement, with ileus and gastric dilatation. These unique findings, not as yet reported, may be attributed to the particular type of a venom of the black widow spider in the Negev. All victims recovered with symptomatic treatment.

Abdominal Pain↗
PubMed1989

[A case of spider bite in Hungary].

The authors introduce their newest case of spider-bite. They demonstrate the consequences of two types of spider bite based on referencial datas.

Animals↗
PubMed1985

[Channel-forming action--a general property of venoms of spiders in the family Theridiidae (Aranei)].

The study of venom action of 10 spider species of Theridiidae family has shown that they cause the formation of the cation selective channels on the bilayer lipid membranes. This action does not depend on the species sex and age and it is the important diagnostic characteristic of the family. The channel-forming effect is due to the presence of the peptide with molecular weight about 5000 daltons in venoms of Theridiidae spider family.

Animals↗
PubMed1986

[Neurotoxin of the black widow spider and its interaction with receptors from the rat brain].

A presynaptic neurotoxin isolated from the venom of the Central Asia spider karakurt (Black Widow Spider, Latrodectus mactans tredecimguttatus) is shown to consist of two identical subunits of mol. weight about 118 kDa. The iodinated neurotoxin binds to the rat brain synaptosomal plasma membranes with Kd 0.1 nM (Bmax 0.1 pmol/mg of protein) at 37 degrees C, and with Kd 0.35 nM (Bmax 0.2 pmol/mg of protein) at 5 degrees C. At intermediate temperatures both types of receptors are detectable. It is supposed that the dimeric form of the toxin interacts with a single class of receptors possessing lateral mobility in the membrane. By the use of different bifunctional reagents it is revealed that the neurotoxin interacts with a presynaptic membrane protein of mol. weight 95 kDa. A protein of the same size accompanied by a 71 kDa protein was isolated by the affinity chromatography of solubilized synaptosomal membranes on the absorbent, containing immobilized neurotoxin.

Animals↗
PubMed1988

Review of southern African spiders of medical importance, with notes on the signs and symptoms of envenomation.

Medically important spiders in southern Africa are discussed in terms of their morphological features and distribution, the signs and symptoms of envenomation and the possible treatment thereof. A simple pictorial key is provided to enable the non-specialist to identify the neurotoxic and cytotoxic species. The following spiders are now known to be medically important in southern Africa: Latrodectus indistinctus (neurotoxic), Chiracanthium lawrencei (cytotoxic), Loxosceles sp. (cytotoxic) and Sicarius sp. (cytotoxic - haemotoxic).

Animals↗
PubMed1987

Envenomation by the sac spider Chiracanthium mildei.

A 19-year-old man was abruptly awakened during the night by the painful bite of a female sac spider, later identified as Chiracanthium mildei. An erythematous urticarial plaque formed immediately. Later, punctate macules appeared, and the bite site became indurated. The clinical response was similar to those reported following bites by Chiracanthium spiders in Japan, Australia, Europe, Massachusetts, Georgia, Indiana, California, and Hawaii. The necrotic lesions associated with some of those bites did not occur in this case. This is the first reported case of C. mildei bite in Connecticut.

Adult↗
PubMed1994

Latrodectus mactans (black widow spider) envenomation: an unusual cause for abdominal pain in pregnancy.

BACKGROUND: The differential diagnosis of abdominal pain in pregnancy is extensive. An important consideration in endemic areas is a bite by a black widow spider. CASE: A 30-year-old woman at 30 weeks' gestation presented with acute abdominal pain following an insect bite. We based the diagnosis on classic symptomatology in an area endemic for Latrodectus mactans. Treatment consisted of supportive therapy and observation. Symptoms resolved over 48 hours and did not recur. The patient delivered a healthy child at 40 weeks' gestation. CONCLUSION: In endemic areas, black widow spider envenomation should be part of the differential diagnosis of abdominal pain in pregnancy.

Abdominal Pain↗
PubMed1997

Heteropodatoxins: peptides isolated from spider venom that block Kv4.2 potassium channels.

Toxins isolated from scorpion, snake, and spider venoms are valuable tools to probe the physiologic function and structure of ion channels. In this study, we have isolated three new toxins (heteropodatoxins) from the venom of a spider, Heteropoda venatoria. These toxins are structurally similar peptides of 29 to 32 amino acids and share sequence homology with hanatoxins isolated from the venom of a Chilean tarantula. The heteropodatoxins prolonged the action-potential duration of isolated rat ventricular myocytes, suggesting that the peptides block K+ currents. The effect of toxins on cardiac K+ currents were studied using voltage clamp techniques. The toxins blocked the transient outward K+ current but not other K+ currents in isolated rat cardiac myocytes. The mechanism of block was studied further using Kv4.2, a cloned channel believed to underlie transient outward K+ current in rat myocytes. The toxins blocked Kv4.2 current expressed in Xenopus laevis oocytes in a voltage-dependent manner, with less block at more positive potentials. In addition, the toxins slowed the time course of current activation and inactivation and shifted the voltage dependence of current inactivation to more positive potentials. The heteropodatoxins represent new pharmacologic probes to study the role of Kv4.2 channels in cardiac and neural tissue.

Action Potentials↗
PubMedDate not supplied

[Poisoning from spider bites. How to treat].

Three types of poisonous spiders that inhabit the Iberian Peninsula are discussed. How to identify these spiders and the type of venom they inject are described. Symptoms and specific treatments, both in the field and in the hospital, are listed.

Animals↗
PubMed2000

Organization of efferent peripheral synapses at mechanosensory neurons in spiders.

The mechanosensory neurons of arachnids receive diverse synaptic inputs in the periphery. The function of most of these synapses, however, is unknown. We have carried out detailed electron microscopic investigations of the peripheral synapses at sensory neurons in the compound slit sense organ VS-3 of the spider Cupiennius salei. Based on the localization of discrete presynaptic vesicle populations, it is possible to discriminate at least four different synapse types, containing either: (1) small round, electron-lucent vesicles 32 nm in diameter; (2) large round, clear 42-nm vesicles; (3) a mixture of small and large clear, round vesicles, similar in size to those in Type 1 and Type 2 synapses, respectively, and granular and dense-core vesicles; or (4) clear, round 37- to 65-nm vesicles. Combined immunocytochemical labeling at the light and the electron microscopic level suggests that gamma-aminobutyric acid (GABA) is the transmitter in many of the 32-nm vesicle synapses, and glutamate in many of the 42-nm ones. Based on vesicle type and particular synaptic configuration, various forms of presumed efferent synaptic contacts are distinguishable with the sensory neurons, the surrounding glia, and between the putative efferent fibers themselves. These include simple unidirectional synapses, reciprocal synapses, serial synapses, and convergent as well as divergent dyads. These various synaptic microcircuits are suited to serve a variety of functions. Among these are direct postsynaptic inhibition or excitation of the mechanosensory neurons, and disinhibition or sensitization via presynaptic inhibition or excitation. The observed synaptic configurations are compared with those at the crustacean muscle receptor organ. They reveal a remarkable complexity of synaptic microcircuits at spider sensilla and suggest manifold possibilities for subtle, efferent control of sensory activity.

Animals↗
PubMed1999

Lipid binding capacity of spider hemocyanin.

The spider hemocyanin capacity to bind different lipid classes was evaluated by measuring some binding kinetic parameters. A very high lipoprotein (VHDL) which contains hemocyanin, was isolated from Polybetes pythagoricus hemolymph plasma and delipidated. Hemocyanin was bound separately to labelled palmitic acid, phosphatidylcholine, cholesterol, and triolein resulting in several artificial lipoprotein structures. It was possible to corroborate in vitro the lipid-hemocyanin interactions which had been previously observed and, consequently, the apolipoprotein role played by the respiratory pigment of spiders. Lipoproteins were analysed by gel filtration chromatography, and three subfractions with different hemocyanin structures were obtained. The four lipid classes were only bound to the hexameric structure (420 Kda), possibly to low polarity sites. Upon radioactivity measurements of the protein-associated lipids, maximal binding ratios (Mr), dissociation constants (Kd), and the maximal binding effectiveness at low lipid concentrations (Eo) were calculated. Lipid/protein ratios were increased proportionally to each available lipid concentration, following a hyperbolic binding model. Values of saturation, affinity, and maximal binding efficiency to hemocyanin were found to be different for each lipid class assayed. The highest lipid/protein ratio (41.5) was obtained with the free fatty acid and the lowest (7.2) with triolein. Phosphatidylcholine and cholesterol showed the highest relative affinities for hemocyanin (Kd = 63 x 10(-5) M and 74 x 10(-5) M, respectively). Phosphatidylcholine at low concentrations, similar to the physiological ones, presented the highest Eo value. Maximal lipid/protein ratios reached in vitro, were greater than those in P. pythagoricus VHDL, pointing out that hemocyanin could play the apolipoprotein role even under physiological conditions with a very high plasma lipid concentration. J. Exp. Zool. 284:368-373, 1999.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

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.

Animals↗
PubMed2001

Spider flagelliform silk: lessons in protein design, gene structure, and molecular evolution.

Spiders spin multiple types of silks that are renowned for their superb mechanical properties. Flagelliform silk, used in the capture spiral of an orb-web, is one of the few silks characterized by both cDNA and genomic DNA data. This fibroin is composed of repeating ensembles of three types of amino acid sequence motifs. The predominant subrepeat, GPGGX, likely forms a beta-turn, and tandem arrays of these turns are thought to create beta-spirals. These spring-like helices may be critical for the exceptional ability of capture silk to stretch and recoil. Each ensemble of motifs was found to correspond to a different exon within the flagelliform gene. The pattern of sequence similarity among exons indicates intragenic concerted evolution. Surprisingly, the introns between the iterated exons are also homogenized with each other. This unusual molecular architecture in the flagelliform silk gene has implications for the evolution and maintenance of spider silk proteins.

Amino Acid Sequence↗