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PubMed1996

Mechanism and possible behavioural relevance of retinal movements in the ctenid spider Cupiennius salei

Like most spiders, the nocturnal hunting spider Cupiennius salei is able to move the retinae of its antero-median (AM) eyes. In the present study, the morphological and physiological properties of the eye muscles and the mechanism and behavioural relevance of retinal movements are investigated. The retinal movements are brought about by two forces: (i) contractions of the dorsal and ventral eye muscles, and (ii) the passive elastic restoring force of the eye tube and eye muscles (the presumed counteracting force). The dorsal eye muscle consists of 15­18 striated fibres and is 600 µm long. The ventral eye muscle is longer (650 µm) and consists of 20­22 striated fibres. The direction of the gaze of the retinae brought about by the eye muscles (active retinal movements) depends on the contraction states of the two eye muscles. The medially directed action of both eye muscles does not allow active movements of the eye tube in any lateral direction. Thus, the direction of gaze cannot actively be shifted medially. After active displacement of the retina, the elasticity of the eye tube and eye muscles passively moves the eye tube back to its resting position. There are two types of retinal movements. (i) Spontaneous microsaccades (duration 80 ms; excursion 3 °) are caused by the spontaneous contraction of only the dorsal eye muscle. They are ideally suited for preventing the adaptation of the sensory cells since their mean excursion (3 °) perfectly fits the inter-receptor angle (2.9 °) in the AM eye of Cupiennius salei. (ii) Induced movements (duration 100­500 ms; excursions 4­15 °) are caused by the contraction of both eye muscles and occur only after mechanical stimulation. Induced movements were elicited by stimulating the mechanosensory organs (trichobothria and slit sense organs) of the spider's legs. A stimulus on one side of the spider induces movements of the ipsilateral retina only. We therefore suggest that induced retinal movements are saccades shifting the gaze of the spider laterally towards the site of mechanical stimulation. According to behavioural experiments, the ability of a spider to locate an immobile target is highly impaired after blinding its AM eyes. We suggest that the motility of the AM eyes is required to locate stationary objects.

Journal Article↗
PubMed2001

Host plant-induced changes in detoxification enzymes and susceptibility to pesticides in the twospotted spider mite (Acari: Tetranychidae).

Adult female twospotted spider mites, Tetranychus urticae Koch, reared on lima bean plants were moved to cucumber, maize, or new lima bean plants (the latter being a control) and evaluated after 24 h or 7 d for changes in susceptibility to three pesticides and in levels of related detoxification enzymes. The largest and most consistent changes were observed in mites feeding on cucumber. Susceptibility of mites on cucumber to the synthetic pyrethroids bifenthrin and lambda-cyhalothrin was greater than that of mites reared on lima bean and maize after only 24 h on the plants, and remained higher after 7 d. Mites on cucumber also were more susceptible to the organophosphate dimethoate than were mites on lima bean, but only after 7 d on the host. Susceptibility was inversely related to activities of both general esterase and glutathione S-transferase (GST) in mites on cucumber; general esterase and GST activities were 60 and 25% lower, respectively, than activities of twospotted spider mite on lima bean after 7 d of feeding. Mites on maize were slightly but significantly more susceptible than those on lima bean to bifenthrin, but not to lambda-cyhalothrin, after 7 d and to dimethoate after 24 h but not after 7 d. General esterase and GST activities in twospotted spider mite fed on maize for 24 h were 20 and 16% higher, respectively, than activities in twospotted spider mite on lima bean, but general esterase activity was 30% lower than lima bean-fed mites and GST was not different after 7 d. Thus, plant-induced changes in general esterase activity, perhaps in combination with GST activity, in twospotted spider mite appear to be inversely related to, and possibly responsible for, changes in susceptibility of twospotted spider mite to several pesticides, particularly the synthetic pyrethroids. General esterases appear to play less of a role in the detoxification of the organophosphate insecticide dimethoate.

Animals↗
PubMed2006

Efficacy and persistence of rosemary oil as an acaricide against twospotted spider mite (Acari: Tetranychidae) on greenhouse tomato.

Efficacy of rosemary, Rosmarinus officinalis L., essential oil was assessed against twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), as well as effects on the tomato, Lycopersicum esculatum Mill., host plant and biocontrol agents. Laboratory bioassay results indicated that pure rosemary oil and EcoTrol (a rosemary oil-based pesticide) caused complete mortality of spider mites at concentrations that are not phytotoxic to the host plant. The predatory mite Phytoseiulus persimilis Athias-Henriot is less susceptible to rosemary oil and EcoTrol than twospotted spider mite both in the laboratory and the greenhouse. Rosemary oil repels spider mites and can affect oviposition behavior. Moreover, rosemary oil and rosemary oil-based pesticides are nonpersistent in the environment, and their lethal and sublethal effects fade within 1 or 2 d. EcoTrol is safe to tomato foliage, flowers, and fruit even at double the recommended label rate. A greenhouse trial indicated that a single application of EcoTrol at its recommended label rate could reduce a twospotted spider mite population by 52%. At that rate, EcoTrol did not cause any mortality in P. persimilis nor did it affect their eggs. In general, EcoTrol was found to be a suitable option for small-scale integrated pest management programs for controlling twospotted spider mites on greenhouse tomato plants.

Animals↗
PubMed2006

Association between sensitization to outdoor spider mites and clinical manifestations of asthma and rhinitis in the general population of adults.

It has been demonstrated that spider mites such as the two-spotted spider mite (Tetranychus urticae) are important allergens for fruit farmers. A total of 2,467 adults (795 metropolitan urban, 788 non-metropolitan urban, and 884 rural subjects) were enrolled. They responded to the questionnaire, and underwent methacholine bronchial provocation tests as well as skin prick tests to locally common aeroallergens including the two-spotted spider mite. The prevalences of asthma and rhinitis as reported on the questionnaire were 7.8% and 16.4% of adults aged 20-35, 9.4% and 24.7% of those 36-50, and 17.7% and 21.7% of those older than 50, respectively. Among the older group, the two-spotted spider mite was the most common sensitizing allergen, although it was second of that of house dust mites among the other two age groups. Sensitization to the two-spotted spider mite was significantly associated with the prevalence of asthma and rhinitis among the younger age group, and associated with the prevalence of rhinitis among the older age group. The two-spotted spider mite might be a common sensitizing allergen in the general population of adults, and sensitization to this mite may play a role in the manifestation of asthma and rhinitis symptoms during adulthood.

Adult↗
PubMed2003

Spider angiomas in patients with liver cirrhosis: role of vascular endothelial growth factor and basic fibroblast growth factor.

AIM: To investigate whether vascular endothelial growth factor (VEGF) and basic fibroblastic growth factor (bFGF) are associated with spider angiomas in patients with liver cirrhosis. METHODS: Eighty-six patients with liver cirrhosis were enrolled and the number and size of the spider angiomas were recorded. Fifty-three healthy subjects were selected as controls. Plasma levels of VEGF and bFGF were measured in both the cirrhotics and the controls. RESULTS: Plasma VEGF and bFGF were increased in cirrhotics compared with controls (122 +/- 13 vs. 71 +/- 11 pg/mL, P=0.003 for VEGF; 5.1 +/- 0.5 vs. 3.4 +/- 0.5 pg/mL, P=0.022 for bFGF). In cirrhotics, plasma VEGF and bFGF were also higher in patients with spider angiomas compared with patients without spider angiomas (185 +/- 28 vs. 90 +/- 10 pg/mL, P=0.003 for VEGF; 6.8 +/- 1.0 vs. 4.1 +/- 0.5 pg/mL, P=0.017 for bFGF). Multivariate logistic regression showed that young age and increased plasma levels of VEGF and bFGF were the most significant predictors for the presence of spider angiomas in cirrhotic patients (odds ratio [OR]=6.64, 95 % confidence interval [CI]=2.02-21.79, P=0.002; OR=4.35, 95% CI=1.35-14.01, P=0.014; OR=5.66, 95% CI=1.72-18.63, P=0.004, respectively). CONCLUSION: Plasma VEGF and bFGF are elevated in patients with liver cirrhosis. Age as well as plasma levels of VEGF and bFGF are significant predictors for spider angiomas in cirrhotic patients.

Age Factors↗
PubMed2001

Clinical characteristics of 500 consecutive patients presenting for laser removal of lower extremity spider veins.

BACKGROUND: Laser treatment for removal of lower extremity spider veins is emerging as a modality of choice in patients with small spider veins, those who have previously undergone sclerotherapy or vein stripping, and those refusing sclerotherapy. OBJECTIVE: To determine clinical characteristics of patients presenting for laser treatment of leg veins. METHODS: The clinical characteristics of 500 patients presenting for laser treatment of spider veins were evaluated to investigate characteristics leading to their development, and to characterize the type of patients presenting for laser treatment. RESULTS: Patients presenting for treatment range widely in age and have had spider veins for an average of 14 years. Both pregnancy and previous sclerotherapy were factors that contributed to the development or exacerbation of spider veins. CONCLUSION: As laser treatment of spider veins improves, this modality will play an increasing role in the management of lower extremity telangiectasias.

Adult↗
PubMed2005

A novel strategy for the identification of toxinlike structures in spider venom.

We compared two different approaches to sequence information analysis from the expressed sequence tag (EST) library constructed for the venom glands of the spider Agelena orientalis. Some results were more illustrative and reliable by the contig analysis technique, whereas our novel method, with specific structural markers introduced for protein structure detection, allowed us to overcome some limitations of the contig analysis. A novel technique was suggested for the identification in data banks of the spider's ion channel inhibitor toxins using primary structure features common to all spiders. Analysis of about 150 polypeptides made it possible to introduce 3 primary structure motifs for spider toxins: the Principal Structural Motif (PSM), which postulates the existence of 6 amino acid residues between the first and second cysteine residue and the Cys-Cys sequence at a distance of 5-10 amino acid residues from the second cysteine; the Extra Structural Motif (ESM), which postulates the existence of a pair of CXC fragments in the C-region; and the Processing Quadruplet Motif (PQM), which specifies the Arg residue at position -1 and Glu residues at positions -2, -3, and/or -4 in the precursor sequences just before the postprocessing site. In the processed data bank we found 48 toxinlike structures with ion channel inhibitor motifs. These include agelenin earlier isolated from Agelena opulenta and 25 more homologous sequences, 15 homologs of mu-agatoxin 2 from the spider Agelenopsis aperta, 3 structures with low homology to omega-agatoxin-IIIA, and 4 new structures. Also we showed that toxinlike structures exceed two thirds of the overall database sequences.

Amino Acid Sequence↗
PubMed2005

Survey for potentially necrotizing spider venoms, with special emphasis on Cheiracanthium mildei.

It has proven difficult to identify those spiders which cause necrotic lesions. In an effort to design a simple, inexpensive screening method for identifying spiders with necrotizing venoms, we have examined the venom gland homogenates of a variety of spider species for their ability to cause red blood cell lysis. Those venoms which were positive were further examined for the presence of sphingomyelinase D, and their ability to evoke necrotic lesions in the skin of rabbits. Sphingomyelinase D is known to be the causative agent of necrosis and red blood cell lysis in the venom of the brown recluse spider (Loxosceles reclusa), and our assumption was that this would be the same agent in other spider venoms as well. This did not prove to be the case. Of 45 species examined, only the venom of L. reclusa and Cheiracanthium mildei lysed sheep red blood cells. Unlike L. reclusa venom, however, C. mildei venom did not possess sphingomyelinase D nor did it cause necrotic lesions in the skin of rabbits. We present evidence suggesting that a phospholipase A2 is the hemolytic agent in C. mildei venom.

Animals↗
PubMed2005

Sphingomyelinase D from venoms of Loxosceles spiders: evolutionary insights from cDNA sequences and gene structure.

Loxosceles spider venoms cause dermonecrosis in mammalian tissues. The toxin sphingomyelinase D (SMaseD) is a sufficient causative agent in lesion formation and is only known in these spiders and a few pathogenic bacteria. Similarities between spider and bacterial SMaseD in molecular weights, pIs and N-terminal amino acid sequence suggest an evolutionary relationship between these molecules. We report three cDNA sequences from venom-expressed mRNAs, analyses of amino acid sequences, and partial characterization of gene structure of SMaseD homologs from Loxosceles arizonica with the goal of better understanding the evolution of this toxin. Sequence analyses indicate SMaseD is a single domain protein and a divergent member of the ubitiquous, broadly conserved glycerophosphoryl diester phosphodiesterase family (GDPD). Bacterial SMaseDs are not identifiable as homologs of spider SMaseD or GDPD family members. Amino acid sequence similarities do not afford clear distinction between independent origin of toxic SMaseD activity in spiders and bacteria and origin in one lineage by ancient horizontal transfer from the other. The SMaseD genes span at least 6500bp and contain at least 5 introns. Together, these data indicate L. arizonica SMaseD has been evolving within a eukaryotic genome for a long time ruling out origin by recent transfer from bacteria.

Amino Acid Sequence↗
PubMed2006

Taxonomy of Australian Funnel-web spiders using rp-HPLC/ESI-MS profiling techniques.

The complex nature of venom from spider species offers a unique natural source of potential pharmacological tools and therapeutic leads. The increased interest in spider venom molecules requires reproducible and precise identification methods. The current taxonomy of the Australian Funnel-web spiders is incomplete, and therefore, accurate identification of these spiders is difficult. Here, we present a study of venom from numerous morphologically similar specimens of the Hadronyche infensa species group collected from a variety of geographic locations in southeast Queensland. Analysis of the crude venoms using online reversed-phase high performance liquid chromatography/electrospray ionisation mass spectrometry (rp-HPLC/ESI-MS) revealed that the venom profiles provide a useful means of specimen identification, from the species level to species variants. Tables defining the descriptor molecules for each group of specimens were constructed and provided a quick reference of the relationship between one specimen and another. The study revealed that the morphologically similar specimens from the southeast Queensland region are a number of different species/species variants. Furthermore, the study supports aspects of the current taxonomy with respect to the H. infensa species group. Analysis of Australian Funnel-web spider venom by rp-HPLC/ESI-MS provides a rapid and accurate method of species/species variant identification.

Animals↗
PubMed2003

Isolation of delta-missulenatoxin-Mb1a, the major vertebrate-active spider delta-toxin from the venom of Missulena bradleyi (Actinopodidae).

The present study describes the isolation and pharmacological characterisation of the neurotoxin delta-missulenatoxin-Mb1a (delta-MSTX-Mb1a) from the venom of the male Australian eastern mouse spider, Missulena bradleyi. This toxin was isolated using reverse-phase high-performance liquid chromatography and was subsequently shown to cause an increase in resting tension, muscle fasciculation and a decrease in indirect twitch tension in a chick biventer cervicis nerve-muscle bioassay. Interestingly, these effects were neutralised by antivenom raised against the venom of the Sydney funnel-web spider Atrax robustus. Subsequent whole-cell patch-clamp electrophysiology on rat dorsal root ganglion neurones revealed that delta-MSTX-Mb1a caused a reduction in peak tetrodotoxin (TTX)-sensitive sodium current, a slowing of sodium current inactivation and a hyperpolarising shift in the voltage at half-maximal activation. In addition, delta-MSTX-Mb1a failed to affect TTX-resistant sodium currents. Subsequent Edman degradation revealed a 42-residue peptide with unusual N- and C-terminal cysteines and a cysteine triplet (Cys(14-16)). This toxin was highly homologous to a family of delta-atracotoxins (delta-ACTX) from Australian funnel-web spiders including conservation of all eight cysteine residues. In addition to actions on sodium channel gating and kinetics to delta-ACTX, delta-MSTX-Mb1a caused significant insect toxicity at doses up to 2000 pmol/g. Delta-MSTX-Mb1a therefore provides evidence of a highly conserved spider delta-toxin from a phylogenetically distinct spider family that has not undergone significant modification.

Amino Acid Sequence↗
PubMed2002

Pharmacology and biochemistry of spider venoms.

Spider venoms represent an incredible source of biologically active substances which selectively target a variety of vital physiological functions in both insects and mammals. Many toxins isolated from spider venoms have been invaluable in helping to determine the role and diversity of neuronal ion channels and the process of exocytosis. In addition, there is enormous potential for the use of insect specific toxins from animal sources in agriculture. For these reasons, the past 15-20 years has seen a dramatic increase in studies on the venoms of many animals, particularly scorpions and spiders. This review covers the pharmacological and biochemical activities of spider venoms and the nature of the active components. In particular, it focuses on the wide variety of ion channel toxins, novel non-neurotoxic peptide toxins, enzymes and low molecular weight compounds that have been isolated. It also discusses the intraspecific sex differences in given species of spiders.

Amino Acids↗
PubMed2000

The influence of hunger and breeding temperature on the venom production of the spider Cupiennius salei (Araneae, Ctenidae).

The venom production of the free hunting neotropic spider Cupiennius salei was tested under different breeding conditions. Three groups kept at different temperatures (17, 21 and 25 degrees C) showed that venom production remained stable within this temperature range, only at a temperature of 15 degrees C the spiders stopped feeding and venom synthesis. Hunger periods do not have a direct effect on the released venom quantity. Two groups of spiders--the first group after a four and the second after an eight weeks hunger period--were compared and no difference in venom production was found. Such long fasting periods are a natural situation for spiders. In this case Cupiennius salei reduces its body weight but not venom supply. This means that body weight is a parameter only of short-term fitness which changes with the actual living conditions (temperature, feeding intervals) of each individual. Long-term fitness is best described by the prosoma length, which was formed during the juvenile growth of each spider and is rather invariable in adulthood. It was shown that the quantity of released venom is better correlated with the length of the prosoma than with the weight of the animal. This means that venom production is mostly an indicator of long-term fitness.

Animals↗
PubMed1993

Red-back spider bites to Perth children, 1979-1988.

The aim of this study was to describe the pattern of illness caused by red-back spider bites to children in Perth, Western Australia, over a 10 year period, and to compare it with that in adults. The case-notes of 241 (89%) of the 271 children admitted to Princess Margaret Hospital and Fremantle Hospital with suspected red-back spider bite from 1979 to 1988 were available for analysis. A definite bite was defined as a definite bite by a positively identified red-back spider, positive identification of a red-back spider with no definite bite but the later development of typical symptoms or no definite history of red-back spider bite but strong clinical evidence and complete recovery after administration of antivenom. Systemic envenomation was accepted if there were symptoms of vomiting, generalized pain or sweating, or abdominal pain. Sixty-five per cent of children were definitely bitten. As found in previous adult and mixed studies, there was a peak incidence in the warmer months with a male preponderance (68%); 81% of bites were to the extremities and 83% of bites occurred in the daytime. The syndrome produced in children was usually similar to that seen in adults. Twenty-one per cent of children received antivenom, a rate comparable to previous studies in older age groups; however, no child received more than one ampoule. Compared with data extracted from a previously published study at Fremantle Hospital, in which 37% of adults treated with antivenom received more than one ampoule, these findings suggest that contrary to current opinion children may not be at an increased risk of morbidity from latrodectism.

Adolescent↗
PubMed1997

[Diversity of joro spider toxins].

In a study to solve a mystery of venom toxicity of the joro spider, Nephila clavata, we purified and identified novel spider toxins such as clavamine, spidamine and joramine. Chemical analyses, bioassays and physical analyses were specifically elaborated in these procedures. The structure-activity relationship of the spider toxins was discussed biologically and chemically in comparison with the other spider toxins. We considered that the diversity of the joro spider toxins by reserving 2,4-dihydroxyphenylacetyl-L-asparaginylcadaverine as a common moiety gave rise to an important insight into not only the toxic reaction, but also the ontology.

Animals↗
PubMed1989

Red-back spider-bites at Fremantle Hospital, 1982-1987.

The published literature in Australia on red-back spider-bites allows no means of determination of the incidence of this envenomation. This retrospective study describes the experience at Fremantle Hospital with red-back spider-bites over a six-year period from 1982-1987 inclusive. One hundred and fifty patients were admitted to hospital with a definite red-back spider-bite, of whom 32 (21%) patients received antivenom; 11 (34%) of these patients received more than one ampoule. In earlier series, only 3% of patients have received more than one ampoule. These results suggest that the WA red-back spider is particularly venomous, and that the annual number of definite red-back spider-bites in Australia lies between approximately 830 and 1950 cases.

Adolescent↗
PubMed1999

Identifying and misidentifying the brown recluse spider.

The brown recluse spider, Loxosceles reclusa, is often implicated as a cause of necrotic skin lesions.[1-3] Diagnoses are most commonly made by clinical appearance and infrequently is a spider seen, captured or identified at the time of the bite.[1, 2, 4-6] The brown recluse lives in a circumscribed area of the U.S. (the south central Midwest) with a few less common recluse species living in the more sparsely-populated southwest U.S.[7] In these areas, where spider populations may be dense, recluse spiders may be a cause of significant morbidity. However, outside the natural range of these recluse species, the conviction that they are the etiological agents behind necrotic lesions of unknown origin is widespread, and most often erroneous. In some states such as California, unsubstantiated reports concerning recluse spider bites have taken on the status of "urban legend" leading to overdiagnosis and, therefore, inappropriate treatment.

Animals↗
PubMed2006

Verified bites by yellow sac spiders (genus Cheiracanthium) in the United States and Australia: where is the necrosis?

Spiders of the genus Cheiracanthium are frequently reported in review articles and medical references to be a definitive cause of dermonecrosis or necrotic arachnidism in humans. We provide 20 cases of verified bites by Cheiracanthium spiders from the United States and Australia, none with necrosis. A review of the international literature on 39 verified Cheiracanthium bites found only one case of mild necrosis in the European species C. punctorium. The basis for the suggestion that this spider genus causes dermonecrosis seems to be mostly inference from venom experiments in rabbits and guinea pigs, circumstantial spider involvement in human skin lesions, and repetitive citation of non-definitive reports in the medical literature. We discuss factors that lead to the erroneous elevation of virtually innocuous spiders to that of significant medical concern, which is a recurring problem in the medical community.

Adolescent↗