| spider toxin and pertussis toxin differentiate post- and presynaptic glutamate receptors. | a specific blocker of the postsynaptic glutamate receptors was found in the venom of the spider nephila clavata. the toxin (jstx) preferentially blocks quisqualate-type glutamate receptors in the crustacean neuromuscular synapse, squid giant synapse and hippocampal neurons in slice preparations. following determination of the structure of jstxs, a main component jstx-3 with its analogs was chemically synthesized and used for the study of structure-activity relationships. 125i-labeled jstx-3 and ... | 1991 | 1660989 |
| spider toxin and the glutamate receptors. | a neurotoxin (jstx) was isolated from the venom of spider (nephila clavata). jstx blocked both the excitatory postsynaptic (epsps) and glutamate-induced potentials in lobster neuromuscular synapse and squid giant synapse. in mammalian central nervous system, jstx blocked the epsps in ca1 pyramidal neurons resulting from stimulation of schaffer collateral/commissure input. pharmacological investigation showed that jstx preferentially suppressed quisqualate/kainate receptor subtypes but was much l ... | 1991 | 1673920 |
| [blocking action of nephila clavata spider toxin on ionic currents activated by glutamate and its agonists in isolated hippocampal neurons]. | the blocking action of the nephila clavata spider neurotoxin was studied using the concentration clamp method in isolated neurons of the rat hippocampus. crude venom jstx blocked l-glutamate-, quisqualate- and kainate-activated ionic currents mediated by activation of the non-n-methyl-d-aspartate (non-nmda) membrane receptors. ionic currents elicited by all agonists were depressed by crude jstx venom to 34-35% of its initial amplitude with no recovery during prolonged washing. an active fraction ... | 1989 | 2474133 |
| effects of a spider toxin (jstx) on hippocampal ca1 neurons in vitro. | the effect of a toxin (jstx) obtained from nephila clavata (joro spider) on the ca1 pyramidal neurons of the hippocampus was studied using slice preparations. jstx blocked the excitatory postsynaptic potentials (epsps) in the pyramidal neuron evoked by schaffer collateral stimulation but was without effect on the antidromic action potentials or on the resting conductance. depolarization induced by ionophoretic application of glutamate was readily suppressed by jstx but aspartate-induced depolari ... | 1989 | 2565131 |
| inhibitory effect of 2,4-dihydroxyphenylacetylasparagine, a common moiety of spider toxin, on glutamate binding to rat brain synaptic membranes. | 2,4-dihydroxyphenylacetylasparagine (2,4-dhpa-asn), a common moiety of molecules of spider toxins, was shown to inhibit l-[3h]glutamic acid binding to rat brain synaptic membranes in a dose-dependent manner. the inhibitory effect of 2,4-dhpa-asn was almost the same as that of intact spider toxin isolated from nephila clavata, but significantly higher than that of 2,4-dihydroxyphenylacetic acid (2,4-dhpa). in addition, neither 2,4-dihydroxybenzoic acid nor the isomers of 2,4-dhpa suppressed the g ... | 1987 | 2827066 |
| molecular action mechanism of spider toxin on glutamate receptor: role of 2,4-dihydroxyphenylacetic acid in toxin molecule. | joro spider toxin (jstx) isolated from nephila clavata was shown to inhibit l-glutamate binding to rat brain synaptic membranes in a dose-dependent manner. 2,4-dihydroxyphenylacetic acid (2,4-dhpa), a common moiety of spider toxins, also inhibited specifically l-glutamate binding at a concentration similar to that of the toxin. the binding activity inhibited by 2,4-dhpa or jstx was recoverable on addition of ferric compound. these results suggest that 2,4-dhpa is a functional moiety in the toxin ... | 1987 | 2889509 |
| ultrastructural and molecular identification of a wolbachia endosymbiont in a spider, nephila clavata. | wolbachia-like bacteria were observed in the egg cells of golden orb-weaving spider, nephila clavata, by means of transmission electron microscopy. the bacteria exhibited the typical morphology of wolbachia, including three enveloping membranes. based on the amplification and sequencing of partial 16s rdna and ftsz gene, the bacteria were identified as wolbachia, intracellular, transovarially inherited alpha-proteobacteria in invertebrates. phylogenetic analysis based on 16s rdna and ftsz gene s ... | 2000 | 11029673 |
| antiepileptic effect of acylpolyaminetoxin jstx-3 on rat hippocampal ca1 neurons in vitro. | the joro spider toxin (jstx-3), derived from nephila clavata, has been found to block glutamate excitatory activity. epilepsy has been studied in vitro, mostly on rat hippocampus, through brain slices techniques. the aim of this study is to verify the effect of the jstx-3 on the epileptiform activity induced by magnesium-free medium in rat ca1 hippocampal neurons. experiments were performed on hippocampus slices of control and pilocarpine-treated wistar rats, prepared and maintained in vitro. ep ... | 2005 | 15913572 |
| hepatoprotective effect of arazyme on ccl4-induced acute hepatic injury in smp30 knock-out mice. | arazyme is a novel protease produced by the hy-3 strain of aranicola proteolyticus, which is a gram-negative aerobic bacterium that has been isolated from the intestine of the spider nephila clavata. this study focused on the hepatoprotective effect of arazyme on carbon tetrachloride (ccl4)-induced acute hepatic injury in senescence marker protein 30 (smp30) knock-out (ko) mice and smp30 wild-type (wt) mice. wt mice and smp30 ko mice were divided into eight groups as follows: (i) two negative co ... | 2008 | 18308447 |
| color development upon reaction of ferric ion with the toxin jstx, a glutamate receptor blocker present in the venom gland of the spider nephila clavata (joro spider). | a spider toxin, jstx, derived from nephila clavata, which blocks glutamate receptor was found to react with fe3+. mechanism of the coloration may be chelate formation since the green color completely faded upon the addition of edta. the colored jstx significantly lost its neurophysiological activity. this unique coloration may be useful for not only detecting specific blockers of the glutamate receptor in spider venom but also for characterizing the glutamate receptor. | 2010 | 2841774 |
| uptake of atmospheric carbon dioxide into silk fiber by silkworms. | the relation between the uptake of atmospheric co(2) and insect's production of silk fiber has not yet been reported. here, we provide the first quantitative demonstrations that four species of silkworms (bombyx mori, samia cynthia ricini, antheraea pernyi, and antheraea yamamai) and a silk-producing spider (nephila clavata) incorporate atmospheric co(2) into their silk fibers. the abundance of (13)c incorporated from the environment was determined by mass spectrometry and (13)c nmr measurements ... | 2013 | 12741798 |
| expression of egfp-spider dragline silk fusion protein in bmn cells and larvae of silkworm showed the solubility is primary limit for dragline proteins yield. | spider dragline silk is a unique fibrous protein with combination of tensile strength and elasticity, but the isolation of large amount of silk from spiders is not feasible. in this paper, we used a newly established bac-to-bac/bmnpv baculovirus expression system to express the recombinant spider (nephila clavata) dragline silk protein (masp1) fused egfp in bmn cells and larvae of silkworm. a 70 kda fusion protein was visualized after rbacmid/bmnpv/drag infection by sds-page and immunoblotting a ... | 2008 | 17525867 |
| structural characterization of a new acylpolyaminetoxin from the venom of brazilian garden spider nephilengys cruentata. | the use of mass spectrometry, in which high-energy cid and charge remote fragmentation both of protonated and sodium-attached molecular ions was applied, afforded the structural elucidation of a new acylpolyaminetoxin with mw=801 da from the venom of the brazilian garden spider nephilengys cruentata. in spite of having the same mw of the nptx-2, previously described in the venom of the joro spider nephila clavata, neither toxins are isomers. in order to differentiate them by using the most usual ... | 1998 | 9637368 |