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PubMedDate not supplied

[The isolation of the Vibrio cholerae dermotoxin and the characterization of its biological properties].

The dermonecrotic factor (dermotoxin) inducing skin necrosis in rabbits has been isolated from V. cholerae strain B-53-2-38 and partially purified. Dermotoxin has a molecular weight of about 110 kD and possesses pronounced cytotoxic and general toxic action, differing from that of enterotoxin. The introduction of this factor into the blood and peritoneum of laboratory animals causes their death.

Animals↗
PubMed1996

Comparison of detection methods for trichothecenes produced by Fusarium sporotrichioides on fodder and grains at different air humidities.

Growth and toxin production of a highly toxic strain of Fusarium sporotrichioides Sherb were studied on oat and wheat grains and on straw under experimental conditions, in which relative humidity (RH) of air was regulated. The materials were incubated at three different RH levels at a range of 84-100%. F. sporotrichioides grew well on oat and wheat grains at RH 97-100% but grew less well at RH 84-88% and on straw. Toxin production was measured with three biological toxicity tests (cytotoxicity test, dermotoxicity test, and yeast cell toxicity test), with chemical analysis, and T-2 ELISA assay. Cytotoxicity and production of trichothecene mycotoxins were detected in all the samples incubated at all three RH levels. On oat and wheat grains, T-2 toxin, neosolaniol, and diacetoxyscirpenol were found, and on straw T-2 toxin, HT-2 toxin, neosolaniol, and T-2 tetraol were determined. In the T-2 ELISA assay, all material samples were found to contain T-2 toxin. The cytotoxicity test was the most sensitive method for detecting biological toxicity of samples inoculated with fungus. The T-2 ELISA assay and chemical analysis were about equally sensitive to detect T-2 toxin in samples.

Animal Feed↗
PubMed2005

Proteome analysis of brown spider venom: identification of loxnecrogin isoforms in Loxosceles gaucho venom.

Brown spiders of the Loxosceles genus are distributed worldwide. In Brazil, eight species are found in Southern states, where the envenomation by Loxosceles venom (loxoscelism) is a health problem. The mechanism of the dermonecrotic action of Loxosceles venom is not totally understood. Two isoforms of dermonecrotic toxins (loxnecrogins) from L. gaucho venom have been previously purified, and showed sequence similarities to sphingomyelinase. Herein we employed a proteomic approach to obtain a global view of the venom proteome, with a particular interest in the loxnecrogin isoforms' pattern. Proteomic two-dimensional gel electrophoresis maps for L. gaucho, L. intermedia, and L. laeta venoms showed a major protein region (30-35 kDa, pI 3-10), where at least eight loxnecrogin isoforms could be separated and identified. Their characterization used a combined approach composed of Edman chemical sequencing, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and electrospray ionization-quadropole-time of flight tandem mass spectrometry leading to the identification of sphingomyelinases D. The venom was also pre-fractionated by gel filtration on a Superose 12 fast protein liqiud chromatography column, followed by capillary liquid chromatography-mass spectrometry. Eleven possible loxnecrogin isoforms around 30-32 kDa were detected. The identification of dermonecrotic toxin isoforms in L. gaucho venom is an important step towards understanding the physiopathology of the envenomation, leading to improvements in the immunotherapy of loxoscelism.

Amino Acid Sequence↗
PubMed1998

Sphingomyelinases in the venom of the spider Loxosceles intermedia are responsible for both dermonecrosis and complement-dependent hemolysis.

The bite of spiders of the genus Loxosceles can induce a variety of biological effects, including dermonecrosis and complement (C) dependent haemolysis. The aim of this study was to characterise the toxins in the venom responsible for the different biological effects. We have previously shown that a 35 kDa protein, named F35, purified from Loxosceles intermedia venom, incorporates into the membranes of human erythrocytes and renders them susceptible to the alternative pathway of autologous C. Here we have further purified the F35 protein which was resolved by reversed phase chromatography into three tightly contiguous peaks termed P1, P2, and P3. P1 and P2 were shown to be homogeneous by SDS-PAGE and N-terminal aminoacid analysis, while P3 consisted of two highly homologous proteins. N-terminal sequencing of all four proteins showed a high degree of homology, which was confirmed by cross-reactivity of antisera raised against the individual purified proteins. Functional characterisation of P1 and P2 indicated the presence of sphingomyelinase activity and either protein in isolation was capable of inducing all the in vivo effects seen with whole spider venom, including C-dependent haemolysis and dermonecrosis. In all assays, P2 was more active than P1, while P3 was completely inactive. These data show that different biological effects of L. intermedia venom can be assigned to the sphingomyelinase activity of two highly homologous proteins, P1 and P2. Identification of these proteins as inducers of the principal pathological effects induced by whole venom will aid studies of the mechanism of action of the venom and the development of a effective therapy.

Amino Acid Sequence↗
PubMed1997

Staphylococcus hyicus exfoliative toxin: purification and demonstration of antigenic diversity among toxins from virulent strains.

The exfoliative toxin produced by Staphylococcus hyicus strain 1289D-88 was purified as a single protein of approximately 30 kDa. Extracellular proteins of S. hyicus grown under small scale fermentation conditions were precipitated with ammonium sulfate. Separation of proteins was performed by hydrophobic interaction chromatography and successively anion exchange chromatography. The purified toxin was tested in a piglet skin assay. Weak epidermal lesions were macroscopically and microscopically similar to lesions caused by (NH4)2SO4-precipitated culture supernatant from the same strain. Addition of 0.5 mM CuSo4 to the purified toxin resulted in more intense skin alterations comparable to lesions caused by precipitated culture supernatant diluted 1:10. These results indicated that the activity of the exfoliative toxin was dependent on the presence of Cu2+. Polyclonal and monoclonal antibodies were prepared against the exfoliative toxin from strain 1289D-88. The in vivo activity of the exfoliative toxin could be neutralized by antibodies. It was shown that polyclonal as well as monoclonal antibodies only reacted with the toxin produced by two of nine well-defined virulent strains of S. hyicus. These results showed antigenic diversity among exfoliative toxins produced by different strains of S. hyicus.

Animals↗
PubMed1994

The characterization of ion channels formed by Pasteurella multocida dermonecrotic toxin.

The influence of the dermonecrotic lethal toxin (approximately 120 kDa) produced by Pasteurella multocida serovarian D on planar phospholipid bilayers was studied. It was found that the toxin is able to increase the conductance of the bilayers by formation of low-conductive and cation-selective ion channels [27 pS at 4.0 M KCl, pH 7.5; zero current potential equals to -14.5 +/- 0.5 mV at threefold transmembrane gradient KCl (120 mM/40 mM)]. In biionic conditions the channels displayed weak selectivity between Na, K and Ca ions. The shapes of current-voltage characteristics (which were measured at different pH and salt concentrations) indicate that an energetic barrier for passing ions is situated near the center of the water pore of the ion channels. The effective diameter of the ion channel's water pore was established to be equal to 2.1 +/- 0.3 nm.

Bacterial Toxins↗
PubMed1984

A two-stage mouse skin carcinogenesis study of lyngbyatoxin A.

A strong skin irritant, lyngbyatoxin A, isolated from the marine blue-green alga Lyngbya majuscula is structurally related to teleocidin. Since lyngbyatoxin A satisfied our short-term screening tests for possible tumor promoters, viz. irritation of mouse ear, induction of ornithine decarboxylase (ODC) in mouse skin, and adhesion of human promyelocytic leukemia cells (HL-60), a two-stage carcinogenesis experiment was carried out. Tumor incidences in the groups treated with 7,12-dimethylbenz(a)anthracene (DMBA) plus lyngbyatoxin A and with DMBA plus 12-O-tetradecanoylphorbol-13-acetate (TPA) were 86.7% and 93.3% in week 30, respectively. The average number of tumors per mouse was 3.7 in the former group and 10.5 in the latter group. This paper reports for the first time the potent tumor-promoting activity of lyngbyatoxin A and also the histological examination of tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

Irritating substance extracted from the Thaumetopoea pityocampa caterpillar; mechanism of action.

Hairs of the Thaumetopoea pityocampa caterpillar (Lepidoptera) cause cutaneous reactions in men and animals. A soluble substance extracted from the hairs has been shown to cause a reaction in guinea-pig skin, probably caused by mediators released by mast cells. A direct effect of this substance on mast cells has been shown. Degranulation of mast cells was found to be dose-dependent. Heating of this substance greatly reduced its effects. Proteins fractions are currently being extracted and will be submitted to the same tests.

Animals↗
PubMed1992

Dermonecrotic and lethal components of Loxosceles gaucho spider venom.

Loxosceles gaucho spider venom causes a typical dermonecrotic lesion in bitten patients and rarely causes lethal systemic effects. Gel filtration on Sephadex G 100 of L. gaucho spider venom resulted in three fractions: fraction A, containing the higher mol. wt components (approximately 35,000); fraction B, containing lower mol. wt components (approximately 15,000); and fraction C, containing very low mol. wt components (probably small peptides). The dermonecrotic and lethal activities were detected exclusively in fraction A. The venom and fraction A produced large dermonecrotic lesions in rabbits with necrosis spreading by gravity to the skin of the lateral body wall. Analysis by SDS-PAGE showed that the proteins contained in fraction A are approximately 35,000 and 33,000 mol. wt. Immunoblotting analysis showed that the proteins responsible for the dermonecrotic and lethal activity are very immunogenic and the first to be detected by antibodies during the course of immunization.

Animals↗
PubMed1992

Comparison of the partition coefficient and skin penetration of a marine algal toxin (lyngbyatoxin A).

Lyngbyatoxin A is produced by marine algae, and causes local cutaneous toxicity in swimmers. The purpose of this research was (1) to determine the partition coefficient of lyngbyatoxin A in octanol/water and (2) to use methods in vitro to measure the penetration and distribution of lyngbyatoxin A in guinea pig and human skin. Discs of excised guinea pig and human skin were mounted in diffusion chambers that exposed the epidermal surface to air and bathed the dermis with HEPES-buffered Hanks' balanced salt solution with gentamicin sulphate. The epidermal surfaces were dosed with 26 micrograms lyngbyatoxin A/cm2 dissolved in 13 microliters dimethyl sulphoxide/cm2. The diffusion chambers were incubated at 36 degrees C for varying periods (1.0-24 hr). HPLC was used to quantify lyngbyatoxin A. Skin penetration was calculated by summing the amount of lyngbyatoxin A recovered from the dermis and receptor fluid. The mean partition coefficient for lyngbyatoxin A was 1.53. Penetration of lyngbyatoxin A (expressed as a percentage of dose, n = 3) in guinea pig and human skin was 23 and 6.2 (respectively) after 1 hr of topical exposure. The amount of lyngbyatoxin A in the dermis and receptor fluid did not change significantly over time.

Animals↗
PubMed1981

Teleocidin, lyngbyatoxin A and their hydrogenated derivatives, possible tumor promoters, induce terminal differentiation in HL-60 cells.

Teleocidin isolated from Streptomyces mediocidicus, its catalytically hydrogenated compound dihydroteleocidin B, and lyngbyatoxin A isolated from marine blue-green alga Lyngbya majuscula as well as its hydrogenated product, tetrahydrolyngbyatoxin A were tested for their ability to induce differentiation of human promyelocytic leukemia cells (HL-60 cells) in culture. All of these indole alkaloids induced differentiation of HL-60 cells, characterized by increased phagocytosis, increased release of lysozyme, and morphological changes resembling macrophages. The concentrations required for the induction were 1-5 ng/ml, showing similarity to those of 12-O-tetradecanoylphorbol-13-acetate (TPA). Teleocidin, lyngbyatoxin A, and tetrahydrolyngbyatoxin A are suggested to be tumor promoters, like TPA and dihydroteleocidin B. The HL-60 cell system might be useful for screening for environmental tumor promoters.

Alkaloids↗
PubMed1990

Cloning and expression of the dermonecrotic toxin gene of Pasteurella multocida ssp. multocida in Escherichia coli.

A DNA library of Pasteurella multocida ssp. multocida strain CVI 47459 was constructed in the Lambda GEM-11 vector. Recombinant clones that encoded dermonecrotic toxin (DNT) were identified immunologically with antiserum raised against purified DNT. By comparing the DNA restriction maps of the immunoreactive recombinants, we located the DNT gene. Hybridization studies with 10 strains of P. multocida ssp. multocida suggested that strains that do not produce the DNT do not contain sequences homologous to the DNT gene.

Bacterial Toxins↗
PubMed1984

A test in vero cell monolayers for toxin production by strains of Pasteurella multocida isolated from pigs suspected of having atrophic rhinitis.

Monolayers of Vero cells showed a morphological change after exposure to supernatants of certain porcine Pasteurella multocida cultures. It appeared possible to screen Pasteurella multocida isolates for their ability to produce toxin and to cause atrophic rhinitis in pigs. A close correlation with the guinea pig skin test was demonstrated.

Animals↗
PubMed2005

Dermatoxin and phylloxin from the waxy monkey frog, Phyllomedusa sauvagei: cloning of precursor cDNAs and structural characterization from lyophilized skin secretion.

Amphibian skin is a morphologically, biochemically and physiologically complex organ that performs the wide range of functions necessary for amphibian survival. Here we describe the primary structures of representatives of two novel classes of amphibian skin antimicrobials, dermatoxin and phylloxin, from the skin secretion of Phyllomedusa sauvagei, deduced from their respective precursor encoding cDNAs cloned from a lyophilized skin secretion library. A degenerate primer, designed to a highly conserved domain in the 5'-untranslated region of analogous peptide precursor cDNAs from Phyllomedusa bicolor, was employed in a 3'-RACE reaction. Peptides with molecular masses coincident with precursor-deduced mature toxin peptides were identified in LC/MS fractions of skin secretion and primary structures were confirmed by MS/MS fragmentation. This integrated experimental approach can thus rapidly expedite the primary structural characterization of amphibian skin peptides in a manner that circumvents specimen sacrifice whilst preserving robustness of scientific data.

Amino Acid Sequence↗
PubMed2002

A synthesis of the phenolic lipid, 3-[(Z)-pentadec-8-enyl] catechol, (15:1)-urushiol.

A synthesis of (15:1)-urushiol, urushiol monoene, 3-[(Z)-pentadec-8-enyl] catechol, 1,2-dihydroxy-3-[(Z)-pentadec-8-enyl] benzene, one of the toxic principles of Rhus toxicodendron and of Rhus vernicifera is described. 6-Chlorohexan-1-ol protected at the OH group with ethyl vinyl ether reacted with 2,3-dimethoxybenzaldehyde in the presence of lithium to give, after removal of the protective group with methanolic 4-toluenesulphonic acid, 1-(2,3-dimethoxyphenyl) heptane-1,7-diol. Catalytic hydrogenolysis in ethanol with palladium-carbon selectively afforded 7-(2,3-dimethoxyphenyl)heptane-1-ol accompanied by a small proportion of the 7-(3-methoxyphenyl)heptane-1-diol, formed by demethoxylation. Reaction of the dimethoxy compound with boron tribromide resulted in both bromination and demethylation to give 7-(2,3-dihydroxyphenyl) heptylbromide. This bromide in tetrahydrofuran (THF) containing hexamethylphosphoric triamide reacted with excess lithium oct-1-yne to give 3-(pentadec-8-enyl)catechol which, by catalytic hydrogenation in ethyl acetate containing quinoline, selectively formed the required cis product, 3-[(Z)-pentadec-8-enyl]catechol which was identical chromatographically and spectroscopically with urushiol monoene separated from the natural product.

Catechols↗