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At least 199 records · Page 11Linked to original sources
PubMed2002

An infestation of 2,055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: implications for bite diagnoses in nonendemic areas.

During a 6-mo period, 2,055 brown recluse spiders, Loxosceles reclusa Gertsch and Mulaik, were collected in a 19th-century-built, currently occupied home in Lenexa, KS. We conservatively estimate that at least 400 of these spiders were large enough to cause envenomation. Additional collections from more typically infested homes in Missouri and Oklahoma in 2001 yielded 45 and 30 brown recluse spiders, respectively. Despite these infestations, no envenomations of the inhabitants of these three homes occurred. Considering the levels of infestations with no bites in the homes presented here, nonendemic areas in the United States, which typically lack recluse spider populations and have had zero to few verified specimens of the spider, do not have sufficient numbers of brown recluse spiders to make envenomation a likely scenario. Despite this, physicians from nonendemic recluse areas often diagnose brown recluse bites which, therefore, are unlikely to be correct.

Animals↗
PubMed2004

Probing the elastic nature of spider silk in pursuit of the next designer fiber.

Spider silk, one of nature's greatest accomplishments, has a combination of strength and elasticity that is unrivaled. Spiders produce up to 7 different silks; each one with a unique combination of tensile strength and elasticity that allows the spiders' web to hold prey while being resilient enough not to break upon impact. In an attempt to determine the sequences responsible for these enviable mechanical properties, several different amino acid motifs have been defined. Much of the recent work is now concentrated on correlating amino acid motifs with a specific mechanical property. The current hypothesis is that the strength property of spider silk is conferred by a poly-alanine or alanine rich (An or GAn) motif whereas the elastic nature of spider silk is conferred by the amino acid motif, GPGXX, where X is Q, S, A, G, or Y. Despite the fact that these different motifs are now known, the combination of strength and elasticity are yet to be duplicated ex vivo. In an attempt to verify that the GPGXX motif imparts elasticity to the spider silk, the number of repeats and/or the amino acid composition of the Argiope aurantia "elastic motif" were varied and expressed in various strains of E. coli to change the elastic properties of the resulting film and/or fiber. Concurrent with work on the elasticity motif is ongoing work on the strength module. Understanding these two different motifs will aide efforts to produce a designer biomaterial for medical, commercial, and military applications.

Amino Acid Sequence↗
PubMed2005

[Inhibitory effect of the venom of spider Macrothele raveni on proliferation of human hepatocellular carcinoma cell line BEL-7402 and its mechanism].

BACKGROUND & OBJECTIVE: Antitumor effect of spider venom has not been reported yet. This study was to explore inhibitory effect of the venom of spider Macrothele raveni on proliferation of human hepatocellular carcinoma cell line BEL-7402 and its molecular mechanism. METHODS: When treated with the venom of spider Macrothele raveni, proliferation of BEL-7402 cells was examined by MTT assay; DNA synthesis of BEL-7402 cells was tested by 3H-TdR incorporation; cell apoptosis and cell cycle were detected by flow cytometry; expression of C-myc was detected by Western blot. RESULTS: The spider venom inhibited proliferation of BEL-7402 cells in time-dependent and concentration-dependent manners with 50% inhibitory concentration (IC(50)) of 20 microg/ml (48 h), and inhibited DNA synthesis of BEL-7402 cells. After treatment of the spider venom, apoptosis of BEL-7402 cells was enhanced, and cells were arrested in G(0)/G(1) phase; expression of C-myc was obviously down-regulated. CONCLUSION: The venom of spider Macrothele raveni could inhibit proliferation and DNA synthesis of BEL-7402 cells, which might through inducing cell apoptosis, down-regulating C-myc, and arresting cell cycle progression of BEL-7402 cells.

Animals↗
PubMed2005

Variations in Loxosceles spider venom composition and toxicity contribute to the severity of envenomation.

Envenomation by Loxosceles spiders causes two main clinical manifestations: cutaneous and systemic loxoscelism. The factors contributing to the severity of loxoscelism are not fully understood. We have analysed biochemical and toxicity variations in venom of L. laeta and L. intermedia, with the aim to find a correlation with the seriousness of loxoscelism. Differences in expression of proteins, glycoproteins and sphingomyelinase activity were observed between venom from male and female spiders and between venom from the two species. These differences were reflected in the toxicity of the venoms including the capacity to induce complement-dependent haemolysis, dermonecrosis and lethality. Comparative analysis of gender and species, showed that these biological activities were more prominent in venom from female spiders, especially from L. laeta. Antiserum raised against venom from females L. laeta spiders had the highest efficacy in neutralizing venoms of males and females of both species. These results indicate that the severity of loxoscelism depends, at least partially, on the species and sex of the spider and suggest that for accidents involving L. laeta an specific serum therapy is necessary. Furthermore, it emphasizes the efficacy of the antiserum produced against L. laeta female venom in neutralizing Loxosceles venoms from different species and gender.

Analysis of Variance↗
PubMed2002

Acute allergic reaction following contact with a spider.

Allergic reactions following contact or injury from arachnids are uncommon. There have previously only been reports of urticarial reactions following contact with large spiders from the family Theraphosidae. A 55-year-old male presented to hospital with a generalised urticarial rash following contact with a spider, identified by the person as a huntsman spider (Family: Sparassidae). The spider had crawled over both his arms for a period of minutes. About 30 min later, he developed a rash on the arms which spread to the trunk. He then developed bradycardia and hypotension that required treatment with atropine, adrenaline and histamine antagonists. He recovered within 6 h and had no further problems. The early allergic reaction in this case was most likely the result of contact with the spider.

Animals↗
PubMed1997

Widow spider envenomation (latrodectism): a worldwide problem.

The objective of this study was to review widow spider envenomation on a worldwide basis, with an emphasis on regional variability in management, particularly between the United States and Australia. Data sources were the Medline database (1966-1997) for English language references using as key words widow spider, latrodectism, and red back spider, and Mesh headings. Textbooks of toxinology were also used. Studies involving clinical reports and series were selected. The data indicated that envenomation by widow spiders (latrodectism) is common worldwide. Local pain and sweating predominate, in about 25% of cases becoming generalized or developing in remote sites. The mortality in published series varies from 5% to 10%, although these may be overestimates. Australia may have the highest rate of latrodectism in the world. The literature reveals regional disparities in the treatment and outcome of latrodectism. In Australia, intramuscular antivenin has been used liberally for more than 40 years with a very low rate (0.5% to 0.8%) of allergic reactions and no deaths recorded since its introduction. Antivenin is routinely successful in relieving the effects of latrodectism. In the United States, the antivenin is given intravenously, is usually reserved for very severe cases, and the rate of allergic reaction is high (from 9% up to 80% in those skin testing positive). Deaths have been recorded after antivenin. The literature suggests that antivenin to one species of Latrodectus is likely to be effective against other species. The conclusion drawn was that latrodectism is a common envenomation worldwide. There is a strong case for a comparative trial of Australian vs US antivenin in treating latrodectism due to the black widow spider in the United States.

Animals↗
PubMed1993

Black and brown widow spider bites in South Africa. A series of 45 cases.

Cases of black widow (Latrodectus indistinctus) and brown widow (L. geometricus) spider bites referred to the Tygerberg Pharmacology and Toxicology Consultation Centre from the summer of 1987/88 to the summer of 1991/92 were entered into this series. Of a total of 45 patients, 30 had been bitten by black and 15 by brown widow spiders. It was evident that black widow spider bites caused a more severe form of envenomation than brown widow bites, characterised by generalised muscle pain and cramps, abdominal muscle rigidity, profuse sweating, raised blood pressure and tachycardia. The symptoms and signs of brown widow bites were mild and tended to be restricted to the bite site and surrounding tissues. Conditions which should be considered in the differential diagnosis include cytotoxic spider bite, scorpion sting, snakebite, acute abdominal conditions, myocardial infarction, alcohol withdrawal and organophosphate poisoning. To prevent the development of complications, the administration of black widow spider antivenom is recommended in severe cases because untreated latrodectism could become protracted, without improvement, for several days.

Adolescent↗
PubMed2000

Biomechanical analysis of vertical climbing in the spider monkey and the Japanese macaque.

Climbing is one of the most important components of primate locomotor modes. We previously reported that the kinesiological characteristics of vertical climbing by the spider monkey and Japanese macaque are clearly different, based on their kinetics and kinematics. In this study, a more detailed analysis using inverse dynamics was conducted to estimate the biomechanical characteristics of vertical climbing in the spider monkey and Japanese macaque. One of the main findings was the difference in forelimb use by the two species. The results of a joint moment analysis and estimates of muscular force indicate that the spider monkey uses its forelimbs to keep the body close to the substrate, rather than to generate propulsion. The forelimb of the Japanese macaque, on the other hand, likely contributes more to propulsion. This supports the idea that "forelimb-hindlimb differentiation" is promoted in the spider monkey. The estimated muscular force also suggests that the spider monkey type of climbing could develop the hindlimb extensor muscles, which are important in bipedal posture and walking. As a result, we conclude that the spider monkey type of climbing could be functionally preadaptive for human bipedalism. This type of climbing would develop the hip and knee extensor muscles, and result in more extended lower limb joints, a more erect trunk posture, and more functionally differentiated fore- and hindlimbs, all of which are important characteristics of human bipedalism.

Animals↗
PubMed1988

Cutaneous spider nevi in liver cirrhosis: capillary microscopical and hormonal investigations.

Nailfold capillary microscopical and hormonal investigations were carried out in 25 patients with cirrhosis of the liver and in 20 age- and sex-matched controls. Several structural and functional capillary microscopical parameters were significantly different between the group of cirrhotics as a whole and the controls; no capillaroscopic feature helped to distinguish cirrhotics with spiders from those without. Serum estradiol and total testosterone were comparable in cirrhotics and controls; free serum testosterone was reduced in male cirrhotics, particularly in cirrhotics with spider nevi. The estradiol/free testosterone ratio was highest in male cirrhotics with spiders. Cirrhosis, thus, leads to both structural and functional effects on the cutaneous capillary system whether or not spider nevi are present. The presence of spider nevi is accompanied by an increased serum estradiol/free testosterone ratio in male cirrhotics. It remains to be determined whether the hormonal alterations described do indeed play a role in spider nevi formation.

Adult↗
PubMed2005

Diapause incidence in the two-spotted spider mite increases due to predator presence, not due to selective predation.

We recently reported evidence for increased diapause incidence in the spider mite Tetranychus urticae in presence of the predatory mite Typhlodromus pyri. This effect may arise from (1) selective predation on non-diapause spider mites, (2) predator-induced diapause in spider mites, or (3) both. Using a different strain of T. urticae, we first recovered increased diapause incidence in association with predators. Then, we tested for selective feeding in two-choice experiments with equal numbers of non-diapause and diapause spider mites. We found that the predatory mite had a significant preference for the latter. This indicates that increased diapause incidence in association with predatory mites is not due to selective predation. Therefore, predator-mediated physiological induction of diapause seems a more likely explanation. The cues leading to induction appear to relate to the predators, not their effects, since predation simulated by spider-mite removal or puncturing did not significantly affect diapause incidence. Why spider mites benefit from this response, remains an open question.

Adaptation, Physiological↗
PubMed2006

The parallelization of SPIDER on distributed-memory computers using MPI.

We describe the strategies and implementation details we employed to parallelize the SPIDER software package on distributed-memory parallel computers using the message passing interface (MPI). The MPI-enabled SPIDER preserves the interactive command line and batch interface used in the sequential version of SPIDER, thus does not require users to modify their existing batch programs. We show the excellent performance of the MPI-enabled SPIDER when it is used to perform multi-reference alignment and 3-D reconstruction operations on a number of different computing platforms. We point out some performance issues when the MPI-enabled SPIDER is used for a complete 3-D projection matching refinement run, and propose several ways to further improve the parallel performance of SPIDER on distributed-memory machines.

Algorithms↗
PubMed2000

Spider-mite problems and control in Taiwan.

Problems with spider mites first appeared in Taiwan in 1958, eight years after the importation of synthetic pesticides, and the mites evolved into major pests on many crops during the 1980s. Of the 74 spider mite species recorded from Taiwan 10 are major pests, with Tetranychus kanzawai most important, followed by T. urticae, Panonychus citri, T. cinnabarinus, T. truncatus and Oligonychus litchii. Most crops suffer from more than one species. Spider mites reproduce year-round in Taiwan. Diapause occurs only in high-elevation areas. Precipitation is the most important abiotic factor restricting spider-mite populations. Control is usually accomplished by applying chemicals. Fifty acaricides are currently registered for the control of spider mites. Acaricide resistance is a serious problem, with regional variation in resistance levels. Several phytoseiid mites and a chrysopid predator have been studied for control of spider mites with good effect. Efforts to market these predators should be intensified so that biological control can be a real choice for farmers.

Animals↗
PubMed2001

Comparison of cultivars of ornamental crop Gerbera jamesonii on production of spider mite-induced volatiles, and their attractiveness to the predator Phytoseiulus persimilis.

We investigated whether volatiles produced by spider mite-damaged plants of four gerbera cultivars differ in attractiveness to Phytoseiulus persimilis, a specialist predator of spider mites, and how the mite-induced odor blends differ in chemical composition. The gerbera cultivars differed in resistance, as expressed in terms of spider mite intrinsic rate of population increase (rm). In order of increasing resistance these were Sirtaki, Rondena, Fame, and Bianca. To correct for differences in damage inflicted on the cultivars, we developed a method to compare the attractiveness of the blends, based on the assumption that a larger amount of spider mite damage leads to higher attraction of P persimilis. Spider mite-induced volatiles of cultivars Rondena and Bianca were preferred over those of cultivar Sirtaki. Spider mite-induced volatiles of cultivars Sirtaki and Fame did not differ in attractiveness to P. persimilis. Sirtaki plants had a lower relative production of terpenes than the other three cultivars. This was attributed to a low production of cis-alpha-bergamotene, trans-alpha-bergamotene, trans-beta-bergamotene, and (E)-beta-farnesene. The emission of (E)-beta-ocimene and linalool was lower in Sirtaki and Fame leaves than in Bianca and Rondena. The importance of these chemical differences in the differential attraction of predatory mites is discussed.

Animals↗
PubMed2006

Toxicity and repellency of hot pepper extracts to spider mite, Tetranychus urticae Koch.

Increasing concern about persistence and environmental impact of synthetic pesticide residues require development of biodegradable and environmentally safe alternatives. The potential of using fruit extracts of hot pepper as alternatives to synthetic acaricides for controlling the two-spotted spider mite, Tetranychus urticae Koch, is explored in this study. Twenty-four Capsicum accessions (Solanaceae) were screened for their toxicity and repellency to the spider mites. Crude extracts from fruits of C. chinense, C. frutescens, C. baccatum, C. annuum, and C. pubescens were prepared in methanol and tested for their acaricidal properties. Spider mite mortality was greatest (45%) when fruit extract of accession Grif-9169 (C. annuum) was used. Results from diving board bioassays indicated that mites avoided filter paper strips treated with hot pepper extracts from accessions PI-596057 (C. baccatum), PI-195299 (C. annuum), and Grif- 9270 (C. annuum). This investigation suggests that methanolic extracts of these three accessions may have a great potential for repelling spider mites and should be field-tested on a large-scale to assess their value in managing populations of spider mites, which could reduce reliance on synthetic acaricides. An attempt was made to correlate repellency with chemical constituents of fruit extracts of the most repellent accessions to identify chemical sources of repellency. Capsaicin and dihydrocapsaicin, the pungent components of pepper fruit, were not correlated with toxicity or repellency, indicating that these are not likely related to the toxicity or repellency of the pepper fruit extracts. Other, unidentified chemicals are likely responsible for toxicity and repellency to the two-spotted spider mite.

Animals↗
PubMed1996

Vimentin-positive spider-shaped Kupffer cells. A new clue to cytologic diagnosis of primary and metastatic hepatocellular carcinoma by fine-needle aspiration biopsy.

The identification of Kupffer cells highlighted by positive immunostaining for vimentin on direct smears was found to play an important role in the diagnosis of primary and metastatic hepatocellular carcinoma by fine-needle aspiration biopsy. The Kupffer cell, identified by vimentin staining, is spider- or star-shaped with multiple elongated and slender cytoplasmic processes. Direct smears obtained by fine-needle aspiration biopsy from 14 cases of hepatocellular carcinoma and 15 cases of metastatic carcinoma were stained with vimentin. The cytologic diagnoses were verified by histologic and/or clinical follow-up. All 14 cases of hepatocellular carcinoma, including 9 primary and 5 metastatic, contained significant number of vimentin-positive spider cells within tumor clusters. There were at least three spider cells present within each tumor cluster, involving at least 50% of the tumor clusters. The spider cells were not only found in the well-differentiated type but also in the poorly differentiated and pleomorphic large cell types of the hepatocellular carcinoma. However, the tumor cells from 15 metastatic carcinomas contained no or few spider cells in the tumor clusters. The presence of numerous vimentin-positive spider-shaped Kupffer cells within tumor clusters constitutes strong evidence in favor of a diagnosis of hepatocellular carcinoma.

Adrenal Gland Neoplasms↗
PubMed1983

IgE-mediated occupational allergy to a spider mite.

Two patients who suffered from allergic rhinitis, conjunctivitis and contact urticaria caused by the two-spotted spider mite (Tetranychus urticae, Koch) are described. Both patients worked in a greenhouse where they came in contact with both spider mites and predator mites living on bean leaves. Prick, Prausnitz-Küstner and RAST tests indicated type I allergy to spider mite but not to predator mite. Both patients had a high level (RAST score 4) of spider-mite-specific IgE in their sera. Radioallergosorbent test (RAST) inhibition studies revealed no cross-reactivity between spider mite and house dust mite allergens. These results show that spider mites, which are herbivorous mites found in nature, in greenhouses and even in homes, can cause IgE-mediated allergy in man.

Adult↗
PubMed2003

Laser therapy of spider leg veins.

BACKGROUND: Spider leg veins are a common aesthetic problem in females. The standard treatment is sclerotherapy but lasers have been used for decades to solve this problem as well. AIM: To review recent advances in laser physics and its tissue interactions with skin vessels. The different laser types used to treat spider leg veins are discussed, including their advantages, limitations and possible adverse effects. METHOD: The international literature on laser therapy for spider leg veins has been reviewed with particular emphasis on the last decade. RESULTS: Recent developments in laser technology allow a more selective and well-tolerated therapy. Efficacy has also improved. Most studies report a greater than 75% improvement in spider leg veins as a realistic goal for laser therapy. Clinic response depends upon wavelength, fluence, pulse width and pulse duration, cooling and the diameter and colour of spider leg veins. CONCLUSIONS: Sclerotherapy remains the gold standard treatment for spider leg veins. Nevertheless, laser therapy has become increasingly efficacious and convenient. Laser selectivity has been improved by technological progress. The ideal laser, however, has yet to be invented.

Journal Article↗
PubMed2004

Spider silks: recombinant synthesis, assembly, spinning, and engineering of synthetic proteins.

Since thousands of years humans have utilized insect silks for their own benefit and comfort. The most famous example is the use of reeled silkworm silk from Bombyx mori to produce textiles. In contrast, despite the more promising properties of their silk, spiders have not been domesticated for large-scale or even industrial applications, since farming the spiders is not commercially viable due to their highly territorial and cannibalistic nature. Before spider silks can be copied or mimicked, not only the sequence of the underlying proteins but also their functions have to be resolved. Several attempts to recombinantly produce spider silks or spider silk mimics in various expression hosts have been reported previously. A new protein engineering approach, which combines synthetic repetitive silk sequences with authentic silk domains, reveals proteins that closely resemble silk proteins and that can be produced at high yields, which provides a basis for cost-efficient large scale production of spider silk-like proteins.

Journal Article↗