881 resultados para Bromeliad-dwelling spider
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Predatory behaviour and reproductive output of the ladybird beetle Stethorus tridens Gordon as function of the tomato red spider mite (TRSM), Tetranychus evansi Baker & Pritchard, densities was investigated in the laboratory. Adult female of S. tridens were isolated in cylindrical plastic arenas, containing a leaf disc of Solanum americanum Mill. with 5, 20, 40, 60, 80 or 100 T. evansi nymphs. The number of prey consumed and eggs laid were evaluated daily for ten consecutive days, starting at the oviposition. Oviposition of S. tridens was positively correlated with prey consumption and lower threshold prey consumption for S. tridens laying eggs was 16.3 mites per day. The instantaneous rate of attack (ca. discovery area) and the handling time were 0.0062 h(-1) and 0.83 h, and 0.00254 h(-1) and 0.78 h, respectively, for predators at the 1st- and 10th-oviposition day. The predator exhibited a type II functional response at 1st- and 10th-oviposition day with a maximum consumption per predator of 33 T. evansi nymphs per day at the highest prey density. The ladybird beetle S. tridens is often collected associated with red spider mite colonies on solanaceous wild plants and the results suggest the potential of this ladybird beetle to control T. evansi in tomatoes crops.
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Tetranychus palmarum sp.nov., a new red spider mite from the African oil palm, is described and figured.
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Two new Tetranychidae (Prostigmata) mites are described from Brazil Monoceronychus tchecensis n. sp., a bryobiine collected from weeping fingergrass, Eustachys distichophylla (Lag.) Nees (Poaceae), in the State of Rio Grande do Sul; and Oligonychus fileno n. sp., a tetranychine collected from grape, Vitis vinifera L. (Vitaceae), in the State of Minas Gerais. Monoceronychus tchecensis n. sp. is the second species in this genus described from South America. In addition to the description of these new species, the tetranychine Eotetranychus smithi Pritchard and Baker, 1955 was recorded for the first time for South America.
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The solution structure of robustoxin, the lethal neurotoxin from the Sydney funnel-web spider Atrax robustus, has been determined from 2D H-1 NMR data, Robustoxin is a polypeptide of 42 residues cross-linked by four disulphide bonds, the connectivities of which were determined from NMR data and trial structure calculations to be 1-15, 8-20, 14-31 and 16-42 (a 1-4/2-6/3-7/5-8 pattern), The structure consists of a small three-stranded, anti-parallel beta-sheet and a series of interlocking gamma-turns at the C-terminus. It also contains a cystine knot, thus placing it in the inhibitor cystine knot motif family of structures, which includes the omega-conotoxins and a number of plant and animal toxins and protease inhibitors. Robustoxin contains three distinct charged patches on its surface, and an extended loop that includes several aromatic and non-polar residues, Both of these structural features may play a role in its binding to the voltage-gated sodium channel. (C) 1997 Federation of European Biochemical Societies.
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Spider toxins that target potassium channels constitute a new class of pharmacological tools that can be used to probe the structure and function of these channels at the molecular level. The limited studies performed to date indicate that these peptide toxins may facilitate the analysis of K+ channels that have proved insensitive to peptide inhibitors isolated from other animal sources. Thus far, two classes of K+ channel-selective spider toxins have been isolated, sequenced, and pharmacologically characterised - the hanatoxins (HaTx) from Grammastola spatulata and heteropodatoxins (HpTx) from Heteropoda venatoria. The hanatoxins block Kv2.1 and Kv4.2 voltage-gated K+ channels. In Kv2.1 K+ channels this occurs as a consequence of a depolarising shift in the voltage dependence of activation and not by occlusion of the channel pore. These toxins show minimal sequence homology with other peptide inhibitors of K+ channels, but they do share some homology with other ion channel toxins from spiders, particularly with regard to the spacing between cysteine residues. We have recently isolated three K+ channel antagonists from the venom of the Australian funnel-web spider Hadronyche versuta; at least two of these toxins are likely to constitute a new class of spider toxins active on K+ channels as they are approximately twice as large as HaTx and HpTx.
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The salticid spider Cosmophasis bitaeniata preys on the larvae of the green tree ant Oecophylla smaragdina. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) reveal that the cuticle of C. bitaeniata mimics the mono- and dimethylalkanes of the cuticle of its prey. Recognition bioassays with extracts of the cuticular hydrocarbons of ants and spiders revealed that foraging major workers did not respond aggressively to the extracts of the spiders or conspecific nestmates, but reacted aggressively to conspecific nonnestmates. Typically, the ants either failed to react (as with control treatments with no extracts) or they reacted nonaggressively as with conspecific nestmates. These data indicate that the qualitative chemical mimicry of ants by C. bitaeniata allows the spiders to avoid detection by major workers of O. smaragdina.
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Chetoneura shennonggongensis Amorim & Niu, sp. n., inhabiting caves in East China, is described based on the adult male and female, plus larva. Chetoneura Colless, previously associated with Orfelia and known from a single species from caves in Malaysia, is formally transferred to the Keroplatini. This is the first description of the larva and of the general biology of the genus. The larva of this new species is suspended in a roughly horizontal hammock of silken threads amidst mucous coated snare threads from the roof of caves, but is not bioluminescent as some species of other genera in Keroplatidae ( e. g., Arachnocampa, Keroplatus, and Orfelia). A key to separate both species of the genus is provided. The position of the genus within the Keroplatini is considered. Chetoneura is considered to be closely related to a clade containing Heteropterna and Ctenoceridion.
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Colonial spiders evolved a differential prey-capture behaviour in concert with their venom chemistry, which may be a source of novel drugs. Some highly active tetrahydro-beta-carboline (TH beta C) toxins were recently isolated from the venom of the colonial spider Parawixia bistriata; the spiders use these toxins as part of their chemical arsenal to kill and/or paralyze preys. The major TH beta C compound isolated from this venom was identified as 6-hydroxytrypargine, also known as PwTX-I. Most natural compounds of animal origin occur in low abundance, and the natural abundance of PwTX-I is insufficient for complete functional characterization. Thus, PwTx-I was synthesized using a Pictet-Spengler condensation strategy, and the stereoisomers of the synthetic toxin were separated by chiral chromatography. The fraction of venom containing a mixture of three natural TH beta C toxins and enantiomers of PwTx-I were analyzed for inhibition of monoamine oxidase (MAO)-A and -B and for toxicity to insects. We reveal that the mixture of the natural TH beta C toxins, as well as the enantiomers of PwTx-I, were non-competitive inhibitors of MAO-A and MAO-B and caused potent paralysis of honeybees. The (-)-PwTX-I enantiomer is 2-fold more potent than the (+)-PwTX-I enantiomer in the assays performed. (C) 2009 Elsevier Ltd. All rights reserved.
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Objective:To determine the risk factors for the presence of moderate/severe vertebral fracture, specifically 25-hydroxyvitamin D (25-OHD). Study design: Cross-sectional study conducted for 2 years in the city of Sao Paulo, Brazil including community-dwelling elderly women. Methods: Bone mineral density (BMD), serum 25-OHD, intact parathyroid hormone (iPTH), calcium and estimated glomerular filtration rate (eGFR) were examined in 226 women without vertebral fractures (NO FRACTURE group) and 189 women with at least one moderate/severe vertebral fracture (FRACTURE group). Vertebral fracture assessment (VFA) was evaluated using both the Genant semiquantitative (SQ) approach and morphometry. Results: Patients in the NO FRACTURE group had lower age, increased height, higher calcium intake, and higher BMD compared to those patients in the FRACTURE group (p < 0.05). Of interest, serum levels of 25-OHD in the NO FRACTURE group were higher than those observed in the FRACTURE group (51.73 nmol/L vs. 42.31 nmol/L, p < 0.001). Reinforcing this finding, vitamin D insufficiency (25-OHD < 75 nmol/L) was observed less in the NO FRACTURE group (82.3% vs. 93.65%, p = 0.001). After adjustment for significant variables within the patient population (age, height, race, calcium intake, 25-OHD, eGFR and sites BMD), the logistic-regression analyses revealed that age (OR = 1.09, 95% Cl 1.04-1.14, p < 0.001) femoral neck BMD (OR = 0.7, 95% CI 0.6-0.82, p < 0.001) and 25-OHD <75 nmol/L (OR = 2.38, 95% CI 1.17-4.8, p = 0.016) remains a significant factor for vertebral fracture. Conclusion: Vitamin D insufficiency is a contributing factor for moderate/severe vertebral fractures. This result emphasizes the importance of including this modifiable risk factor in the evaluation of elderly women. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
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A family of potent insecticidal toxins has recently been isolated from the venom of Australian funnel web spiders. Among these is the 37-residue peptide omega-atracotoxin-HV1 (omega-ACTX-HV1) from Hadronyche versuta. We have chemically synthesized and folded omega-ACTX-HV1, shown that it is neurotoxic, ascertained its disulphide bonding pattern, and determined its three-dimensional solution structure using NMR spectroscopy. The structure consists of a solvent-accessible beta-hairpin protruding from a disulphide-bonded globular core comprising four beta-turns. The three intramolecular disulphide bonds form a cystine knot motif similar to that seen in several other neurotoxic peptides. Despite limited sequence identity, omega-ACTX-HV1 displays significant structural homology with the omega-agatoxins and omega-conotoxins, both of which are vertebrate calcium channel antagonists; however, in contrast with these toxins, we show that omega-ACTX-HV1 inhibits insect, but not mammalian, voltage-gated calcium channel currents.
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Objectives: To estimate the prevalence of fibromyalgia (FM) and chronic widespread pain (CWP) in community-dwelling elderly individuals living in Sao Paulo, to assess the spectrum of problems related to these diseases using the Fibromyalgia Impact Questionnaire (FIQ) and to correlate the FIQ with the number of tender points and with pain threshold. Methods: Our sample consisted of 361 individuals (64% women, 36% men, mean age of 73.3 +/- 5.7 years). Individuals were classified into four groups: FM (according to American College of Rheumatology criteria), CWP, regional pain (RP) and no pain (NP). Pain characteristics and dolorimetry for 18 tender points and the FIQ were assessed. Results: The prevalence of FM was 5.5% [95% confidence interval (CI) = 5.4-5.7], and the prevalence of CWP was 14.1% (95% Cl: 10.5-17.7%). The frequency of RP was 52.6% and the prevalence of NP was 27.7%. FIQ scores were higher in people with FM (44.5), followed by CWP (31.4), RP (18.1) and NP (5.5) (p < 0.001). There was a positive correlation between the domains of the FIQ and the number of tender Points (p < 0.05), and a negative correlation between FIQ score and pain threshold (p < 0.05). Conclusion: In our elderly subjects, the prevalence of FM was slightly higher compared to previously reported studies, and CWP was around 14%. The spectrum of problems related to chronic pain was more severe in FM followed by CWP, strongly suggesting that these conditions should be diagnosed and adequately treated in older individuals. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
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The risk of osteoporotic fractures is known to vary among populations. There are no studies analyzing concomitantly clinical, densitometric, and lab risk factors in miscigenated community-dwelling population of Brazil. A total of 1007 elderly subjects (600 women and 407 men) from Sao Paulo, were evaluated using a questionnaire that included risk factors for osteoporotic fractures. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at the hip and lumbar spine. Laboratory blood tests were also obtained. The prevalence of osteoporotic fractures was 13.2% (133 subjects), and the main fracture sites were distal forearm (6.0%), humerus (2.3%), femur (1.3%), and ribs (1.1%). Women had a higher prevalence (17.5%; 95% confidence interval [CI]: 14.6-20.6) than men (6.9%; 95% CI: 4.4-9.3) (p < 0.001). After adjusting for significant variables, logistic regression revealed that female gender (odds ratio [OR] = 2.7; 95% CI; 1.6-4.5; p < 0.001), current smoking (OR = 1.9; 95% CI: 1.2-3.3; p = 0.013), and the femoral neck T-score (OR = 0.7; 95% CI: 0.5-0.9; p = 0.001) remain significant risk factors for osteoporotic fractures in the community-dwelling elderly. Our findings identified that female gender, current smoking, and low hip BMD are independent risk factors for osteoporotic fractures.
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The peptides Tx2-5 and Tx2-6, isolated from the whole venom of ""armed-spider"" Phoneutria nigniventer venom, are directly linked with the induction of persistent and painful erection in the penis of mammals. The erection induced by Tx2-6 has been associated with the activation of nitric oxide synthases. There is a scarcity of studies focusing on the outcome of Tx2-6 at the molecular level, by this reason we evaluated the gene profile activity of this toxin at the nitric oxide (NO) pathway. After microarray analyses on cavernous tissue of mice inoculated with Tx2-6 we found that only 10.4% (10/96) of these genes were differentially expressed, showing a limited effect of the toxin on the NO pathway. We found the genes sparc, ednrb, junb, cdkn1a, bcl2, ccl5, abcc1 over-expressed and the genes sod1, s100a10 and fth1 under-expressed after inoculation of Tx2-6. The differential expressions of sparc and ednrb genes were further confirmed using real-time PCR. Interestingly, ednrb activates the L-arginine/NO/cGMP pathway that is involved in the relaxation of the cavernous body. Therefore the priapism induced by Tx2-6 is a consequence of a highly specific interference of this neurotoxin with the NO pathway. (C) 2009 Elsevier Ltd. All rights reserved.
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Objectives To assess the prevalence of alcoholism in elderly living in the city of Sao Paulo (Brazil) and investigate associated risk factors. Methods A total of 1,563 individuals aged 60 years or older, of both genders of three districts of different socioeconomic classes (high, medium and low) in the city of Sao Paulo (Brazil) were interviewed. The CAGE screening test for alcoholism was applied and a structured interview was used to assess associated sociodemographic and clinical factors. The tests Mini Mental State Examination, Fuld Object Memory Evaluation, The Informant Questionnaire on Cognitive Decline in the Elderly and Bayer-Activities of Daily Living Scale were used for cognitive and functional assessment. Results Prevalence of alcoholism was 9.1%. Multivariate regression analysis showed that alcoholism was associated with male gender, `mulatto` ethnicity, smoking, and cognitive and functional impairment. In addition, the younger the individual and the lower the schooling level, the higher the risk for alcoholism. Conclusions The results obtained in this study show that alcoholism is highly frequent in the community-dwelling elderly living in Sao Paulo, and that it is associated with socio-demographic and clinical risk factors similar to those reported in the literature. This suggests that alcoholism in the elderly of a developing country shares the same basic characteristics seen in developed countries. These findings suggest that it is essential for health services and professional to be prepared to meet this demand that will significantly grow in the next years, especially in developing countries, where the rates of population aging are higher than those of developed countries. Copyright (C) 2009 John Wiley & Sons, Ltd.
Penile erection induced in vivo by a purified toxin from the Brazilian spider Phoneutria nigriventer
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OBJECTIVES To verify the effect on erectile tissue of mice of two neuropeptides extracted from the poison of a spider, Phoneutric nigriventer, (Tx2-5 and -6. termed `eretina`) after direct injection into the corpus cavernosum, to assess the minimum dosage necessary for effect. the time for initiation of action, the local duration of the erection, histological effects and the presence of local and systemic side-effects. MATERIALS AND METHODS When applied intraperitoneally, eretina promotes the relaxation of cavernous smooth muscle, thus causing penile erection. Thirty-five mice were divided in two groups; 10 control mice were injected 20 mu L of saline solution, and in the treated group, 25 mice were divided into groups of five and each subgroup received eretina in decreasing doses (0.024, 0.012, 0.006, 0.003 and 0.0015 mu g/kg) until the minimum dose that produced an erection was determined. After treatment 211 mice were monitored to determine the response and any collateral effects. RESULTS The minimum dose producing an erection was 0.006 mu g/kg, the five mice in this group having evidence of an erection at 35-45 min after injection. The histology of the cavernosum of mice treated with eretina showed dilatation and congestion of the vascular spaces with more blood than in controls. With the minimum dose there were no local or systemic collateral effects and the erection was lost after 120-140 min. CONCLUSION The minimum dose of eretina producing an erection in mice was determined. and the agent was safe for this use as it did not produce any collateral toxic effects. These studies indicate a possible means of determining the mechanism of action of eretina.