Evaluation of impact of sewage irrigation on cytotoxicological potentialities of Chenopodium album in Allium assay.

Chenopodium album is a weed commonly consumed by North Indian population as vegetable. Plants are known to accumulate toxins from their environment. Presently, the leaf homogenates of these plants growing in a tubewell irrigated field and a sewage irrigated field were evaluated for cytotoxicological effects in Allium root tip assay. Studies revealed that Chenopodium album was mildly mitodepressive in nature and was capable of inducing chromosomal aberrations. The leaf homogenate of the plants growing in sewage irrigated fields induced more quantum of aberrations than the plants from the control site. This has a direct bearing on consumability of sewage grown vegetables and fodder.

Effect of toxin-g from Tityus serrulatus scorpion venom on gastric emptying in rats

The effect of toxin-g from Tityus serrulatus scorpion venom on the gastric emptying of liquids was studied in 176 young adult male Wistar rats (2-3months of age) divided into subgroups of 8 animals each. Toxin-g was injected iv at doses of 25, 37.5, 50 or 100 µg/kg and the effect on gastric emptying was assessed 30 min and 8 h later. A time-course study was also performed by injecting 50 µg of toxin-g /kg and measuring the effect on gastric emptying at times 0.25, 0.5, 1, 2, 4, 8, 24 and 48 h post-venom. Each envenomed animal was paired with its saline control and all received a saline test meal solution containing phenol red (60 µg/ml) as a marker. Ten minutes after administering the test meal by gavage the animals were sacrificed and gastric retention was determined by measuring the residual marker concentration of the test meal. A significant delay in gastric emptying, at 30 min and 8 h post-venom, was observed only after 50 and 100 µg of toxin-g /kg compared to control values. The responses to these two doses were significantly different after 8 h post-venom. Toxin-g (50 µg/kg) significantly delayed the gastric emptying of liquids at all times studied, with a peak response at 4 h after toxin administration compared to control values. These results indicate that the iv injection of toxin-g may induce a rapid, intense and sustained inhibition of gastric emptying 0.25 to 48 h after envenomation.

An in vitro study of the effects of venom of Australian elapids on murine skeletal muscle and the protective effect of homologous plasma

The venom of many dangerous Australian snakes has a myotoxic component and some are strongly myolytic. The myotoxicity of venom of seven Australian elapid snakes was studied to determine their relative in vitro potency in causing cell death of C2C12 cells, a myoblast cell line, and murine pmyotubes in mixed cell culture. The venom of Pseudechis australis proved to be most myotoxic, Austrelaps superbus and Pseudechis porphyriacus venoms also exhibited myotoxicity relative to the other venoms tested. The specificity of Pseudechis porphyriacus venom was tested using the human glioma cell line TC3 and was shown to exhibit a general cytotoxicity. Myotoxicity, however, was the predominant action of the venom. It has long been known that certain animals sucha as the mongoose (herpestes edwardsii) are able to survive envenomation. Some species of snakes also possess this property and the neutralising factor(s) responsible for this P. porphyriacus has been shown to be present in the serum. The protective effect of homologous plasma from P. porphyriacus venom was also studied with reference to myotoxicity and cytotoxicity. The results of this study clearly demonstrated protection by homologous plasma using a myoblast cell line, C2C12, a primary mixed cell culture and TC3 cells. While protection was clear, particularly using high concentrations of venom, it was not absolute, and homologous plasma did not afford continued protection from the effects of the venom. In the mixed culture experiments venom/plasma mixtures pre-incubated for 30 min were more protective than venom/plasma mixtures which were not incubated, in contrast to the results of cell culture studies, which showed little difference.

Purification and properties of a cardioactive toxin, cardioleputin, from stonefish, Synanceja verrucosa

Cardioleputin, a new cardioactive toxin, was purified from a stonefish venom using column chromatographies. The purified toxin was found to be an unstable protein that was susceptible to heat and freeze-thawing. This protein showed to have a molecular size of 46,000 daltons, and its amino acid composition was rich in serine and glycine, but low in basic amino acids. The crude venom induced a sudden drop in blood pressure and heart rate of rats right after administration. Both the blood pressure and heart rate returned to their original values as time elapsed, and thereafter continued to show a gradual decrease. In addition, crude venom actively affected the contractile response and suppressed the heart rate of guinea pig atria. The purified toxin caused irreversible inotropical and chronotropical increases in guinea pig atria. The action of the toxin on the atria was completely different from that of lysolecithin. It might be suggested that the toxin acts on the Ca++ ion channel of the atrial membrane.

In vitro activity of the killer toxin from the yeast hansenula anomala against some different microorganisms

The killer toxin of Hansenula anomala showed killer activity toward some different microrganisms. The killer toxin produced by this species was purified. This toxin inhibited completely the growth of 2 species of yeasts,. Candida albicans, and CKefyr; three species of dermatophytes, Microsporum gypseum, M. Canis and Trichophyton mentagrophytes; and 2 species of moulds Fusarium solani and Aspergillus terreus tested at concentrations 100 ul/ml or less. The minimum inhibitory concentration [MIC] of the killer toxin against Candida guilliermondii and C. parapsilosis tested was 20 ul/ml or more. [MIC] of the killer toxin against, M. audoiunii, Sepedomium chrysospermun and Penicillium Coryophilum tested was 60 ul/ml or more. Finally the [MIC] of this killer toxin against the following bacterial strains: Proteus Vulgaris. Staphylococcus aureus, Salmonella typh, E. coli and Rhizobium legumnosarum tested was 25 ul/ml or more. But the [MIC] of this toxin against the two species of: Bacillus subtilus and Pseudomonas areuginosa was 50 ul/ml or more. In this paper we found that the purified H. anomala killer toxin used for the determination the [MIC] of a wide range of yeasts, moulds and bacteria including a number of important species

Scorpion toxin induces alterations on jejunal absorption of chlorides and jejunal motility of male albino rats

The effects of an intravenous bolus injection of 25 ug x 100 g (-1) b.w. of a purified toxin from the Brazilian scorpion Tityus serrulatus on the rat jejunal absorption and secretion of water, glucose, sodium and chloride were studied in a jejunal loop perfused "in situ" using polyethyleneglycol as a marker, in anesthetized animals. The results seem to indicate that only chloride transport was affected by the toxin as the data analysis have shown a statistically significant increase in the absorption of that ion, while the sodium, glucose and water values before and after toxin remained the same. The addition of toxin into an organ bath containing a segment of jejunum immersed in Tyrode's solution evoked a strong and sustained contraction followed by oscillations of tonus. These effects were resistant even to repeated washings with the bathing solution, but were partially abolished by atropine.

Canatoxin induces activation on mice peritoneal macrophages

Canatoxin (CNTX), the toxic protein from Canavalia ensiformis seeds, injected into the peritoneal cavities of mice (10 micrograms/cavity) induced a significant neutrophil migration (10.5 +/- 0.5 x 10(6) cells/cavity) after 4 h. A later migratory effect (48 h) on mononuclear cells, predominantly macrophages, was also observed (controls: 7 +/- 0.9; CNTX: 17 +/- 2.0 x 10(6) cells/cavity). These CNTX-elicited macrophages, when compared to resident cells (R) or cells elicited by thioglycollate (TG), had an increased content of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (R: 4.5 +/- 0.5; TG: 7.2 +/- 1.0; CNTX: 20.2 +/- 3.0 mU/10(6) cells) and a greater (> or = 100%) phagocytic activity. The data suggest that CNTX-stimulated macrophages presented some characteristics of activated cells

Effect of canatoxin on the circulating levels of gonadotropins and prolactin in rats

1. The effects of canatoxin, the toxic principle from Canavalia ensiformis seeds which has lipoxygenase-activating properties, were evaluated in rats using radioimmunoassay techiniques to measure plasma levels of prolactin (PRL), progesterone, follicle stimulating (LH) and luteinizing (LH) hormones. 2. The chronic administration of canatoxin (50, 100 or 200 microng/Kg daily for 12 days, ip) to female rats induced a sharp rise in plasma LH and FSH concentrations whit no changes in progesterone level. A fall in circulating PRL was also observed. The frequency of proestrus and weight gain increased in rats treated with the higest dose of toxin used, but there was no alteration in weight of uterus or ovaries. 3. The increases in gonadotropin levels with canatoxin are consistent with the lipoxygenase-activating properties of the toxin, but do not explain why plasma PRL concentrations decreased in canatoxin-treated rats. 4. Since the animals in the control group had high PRL and low LH levels and since canatoxin increased LH and decreased PRL in the circulation, a possible stress-prevention effect is discussed for the toxin. 5. This study supports previous suggestions of central actions for canatoxin, and indicates the hypophysis and/or hypothalamus as one of the target sites for the toxin in the central nervous system

Lysis of red blood cells by extracts from benthic dinoflagellates

Samples of the cultured benthic dinoflagellates Gambierdiscus toxicus and Ostreopsis lenticularis, both isolated from a shalow back reef habitat in soutwestern Puerto Rico, were estracted in methanol, dried and resuspended in distilled water. After centrifugation, aliquots of the supernatant, or dilutions thereof, were added to suspensions of washed human and mouse red blood cells and incuated at different temperatures for different time periods. Further spectrophotometrical examinations of the samples showed a hemolytic activity aginst mouse and human red blood cells. The hemolytic activity of G. toxicus extract was 3 to 4 times greater than that of O. lenticularis and was less temperature-dependent. Such findings suggest that these two dinoflagellates produce chemically different hemolysins

Farmacologia do canal do sódio: modo de açäo de toxinas / Pharmacology of the sodium channel: mode of action of toxins

O esclarecimento do mecanismo de açäo de numerosas toxinas vem permitindo o seu emprego no estudo de vários fenômenos fisiológicos e a melhor compreensäo da gênese dos sinais e sintomas observados no envenenamento que provocam. O conhecimento do modo de açäo das toxinas que atuam no canal do sódio voltagem-dependente é importante do ponto de vista de ambos os aspectos referidos. As toxinas podem: bloquear o canal do sódio, retardar a sua inativaçäo ou causar ativaçäo persistente do mesmo. Certas toxinas, compostos policíclicos de pequeno peso molecular, existentes em tecidos de alguns peixes e anfíbios (tetrodotoxina) ou elaborados por dinoflagelados (saxitoxina) bloqueiam reversível e seletivamente o canal do sódio. Em conseqüência inibem a formaçäo e propagaçäo do potencial de açäo. Retardam a inativaçäo do canal do sódio certas toxinas polipeptídicas da peçonha de escorpiöes da Africa e Asia (toxinas alfa-escorpiônicas) e dos nematocistos de algumas anêmonas-do-mar. Em virtude de retardarem a inativaçäo do canal, prolongam a duraçäo do potencial de açäo. As toxinas que produzem ativaçäo do canal de sódio causam despolarizaçäo persistente da membrana das células excitáveis do organismo. Algumas däo origem também a respostas iterativas. Compreendem dois grupos distintos: toxinas "alcaloídicas" (batrachotoxina, alcalóides do veratrum, aconitina, graianotoxina) e toxinas polipeptídicas (toxinas ß-escorpiônicas da peçonha de escorpiöes dos EUA, México e América Central, peçonha da aranha Phoneutria nigriventer e a crotamina, toxina da peçonha da cascavel sul-americana). A açäo da crotamina distingui-se das demais por ser seletiva para o canal do sódio de fibras musculares

Mecanismo de acción de miotoxinas aisladas de venenos de serpientes / Mechanism of action of myotoxins isolated from snake venoms

Desde los puntos de vista bioquímico y farmacológico, las miotoxinas aisladas de venenos de serpientes se ubican en cuatro grupos: (1) Fosfolipasas A miotóxicas, (2) miotoxinas básicas de bajo peso molecular, (3) cardiotoxinas de venenos elapídeos y (4) miotoxinas hemorrágicas. Las fosfolipasas miotóxicas notexinam taipoxina, crotoxina y miotoxina de Bothrops asper afectan inicialmente la integridad de la membrana plasmática, induciéndose un influjo de calcio que culmina con la muerte celular. Las miotoxinas básicas de bajo peso molecular crotamina y miotoxina a actúan específicamente en los canales de sodio del sarcolema, induciendo un influjo de sodio que trae como consecuencia despolarización y contracción muscular y vacuolización del retículo sarcoplásmico. Las cardiotoxinas son polipéptidos básicos capaces de desorganizar la estructura de las membranas, siendo su acción miotóxica una consecuencia de la alteración drástica que las mismas inducen en el sarcolema del músculo esquelético. Finalmente, dos componentes hemorrágicos (toxina hemorrágica b y viriditoxina) poseen actividad miotóxica, habiendose sugerido que este efecto es una consecuencia de la isquemia tisular resultante de la acción hemorrágica de estos componentes