Isoverrucarol production by Fusarium oxysporum CJS-12 isolated from corn

Isoverrucarol (3,15-dihydroxy-12,13-epoxy-trichothec-9-ene) was isolated and purified from wheat cultures of a toxic strain of Fusarium oxysporum CJS-12. The toxin was characterized by thin-layer chromatography, gas chromatography-mass spectrometry, and 1H and 13C nuclear magnetic resonance spectrometry. Isoverrucarol caused toxic effects in rats, including loss of appetite, bodily weakness, severe mucosae of the stomach, and death, when administered orally at 10 and 20 mg/kg of body weight. The toxin also caused a definite dermatitic reaction of epidermis and an edematic-necrotic response of the dermis.     

Protein reagent modification of cholera toxin: characterization of effects on antigenic, receptor-binding and toxic properties.

The effects of protein modification procedures on the biologically most important properties of cholera toxin, i.e. the toxic activity, the GM1 receptor-binding capacity and the antigenic (antibody-fixing) properties, have been studied quantitatively using microgram amounts or less of toxin protein. Most of the 24 group-specific reagents used had either no inhibitory effect on the toxic or the combination of GM1-binding and antibody-fixing properties of cholera toxin, or they had a concomitant inhibitory effect on these activities. Separate testing of GM1- and antibody-binding revealed a close, but not absolute, structural association between these properties, Amino group reactive substances were particularly effective in decreasing the GM1-binding activity, while leucine aminopeptidase had no effect. This suggests that lysine residues may be involved in binding toxin to the acidic GM1 receptor. Sodium dodecylsulphate and mercaptoethanol, which caused dissociation of the subunits of cholera toxin as indicated by polyacrylamide gel electrophoresis, abolished toxicity without inhibiting the concomitant GM1- and antibody-binding properties of the toxin. Similar differential effects were also obtained with three reagents which did not seem to change the aggregation state of the toxin. These substances all had specificity for arginine, suggesting that arginyl residues of the toxin molecule may be involved in a 'toxic site' distinct from the receptor-binding site(s). A selective effect on the toxic site was also found by treating the toxin with carboxypeptidase or trypsin in the presence of urea; in the absence of urea no enzymic effect on any toxin property was noted.     

Purification and partial characterization of a toxin produced by Ganoderma lucidum,the coconut Ganoderma disease pathogen

Abstract

An extracellular, hydrophilic, thermostable phytotoxin was purified to homogeneity from culture fluids of Ganoderma lucidum. The phytotoxin was purified by solvent extraction, gel filtration on Sephadex G-75. Toxicity was evaluated with detached leaf sheath and electrolyte leakage bioassays. Purified phytotoxin induced visible symptoms of the disease, when applied to coconut leaves, fronds and roots even at a low concentration. The toxin is a glycoprotein with carbohydrate as the major component. The importance of the carbohydrate moiety for toxic activity was indicated by inactivation of toxic compounds after periodate oxidation. The toxin caused lesions on a number of other monocots and dicots and proved to be non-host specific.     

Cross-Resistance to Bacillus thuringiensis Toxin CryIF in the Diamondback Moth (Plutella xylostella)

Selection with Bacillus thuringiensis subsp. kurstaki, which contains CryIA and CryII toxins, caused a >200-fold cross-resistance to CryIF toxin from B. thuringiensis subsp. aizawai in the diamondback moth, Plutella xylostella. CryIE was not toxic, but CryIB was highly toxic to both selected and unselected larvae. The results show that extremely high levels of cross-resistance can be conferred across classes of CryI toxins of B. thuringiensis.     

Identification of a mosquitocidal toxin from Bacillus thuringiensis using mass spectrometry

The Bacillus thuringiensis strain S2160-1 has previously been identified as being highly toxic to mosquito larvae and a viable alternative to strains currently used commercially to control these insects. A PCR approach had identified the presence of four putative insecticidal toxin genes (cry30Ea, cry30 Ga, cry50Ba and cry54Ba) in this strain, but did not identify the genes that encoding three of the main crystal toxin proteins of size 140 and 130 and 30 kDa. In this study we used mass spectrometry to identify the 130 kDa toxin as a rare Cry4 toxin (Cry4Cb3). The gene encoding this toxin was cloned and expressed and the toxin shown to have mosquitocidal activity against Culex quinquefasciatus.     

Production of neosolaniol byFusarium tumidum

Extracts from autoclaved maize culture ofFusarium tumidum strain R-5823 were toxic towardsArtemia salina. Bioassay-guided fractionation of the organic extract led to the isolation of the toxic compound that was identified as the trichothecene toxin neosolaniol (NEOS) by¹H,¹³C nuclear magnetic resonance spectroscopy and low-resolution electronic impact mass spectrometry. The amount of NEOS produced by the strain R-5823 was 300 mg/kg maize culture. NEOS was also detected by HPLC in cultures of four out of seven additional strains ofF. tumidum andGibberella tumida with different origin, in amounts ranging from 1 to 311 mg/kg. This is the first report on the production of a trichothecene toxin byF. tumidum.     

Purification and partial characterization of a phytotoxin produced by sarocladium oryzae,the rice sheath rot pathogen: Reinigung und partielle charakterisierung eines vom reisblattscheidenfäule-pathogen sarocladium oryzae erzeugten phytotoxins

An extracellular, hydrophilic, thermostable phytotoxin was purified to homogeneity from culture fluids of Sarocladium oryzae and sheath rot infected rice plants. The phytotoxin was purified by solvent extraction, gel filtration on Sephadex G-75 and HPLC. Toxicity was evaluated with detached leaf sheath and electrolyte leakage bioassays. Purified phytotoxin induced visible symptoms of the disease, when applied to rice sheath even at a low concentration of 5?μg. The toxin is a glycoprotein with carbohydrate as major component. The importances of the carbohydrate moiety for toxic activity was indicated by inactivation of toxic compound after periodate oxidation. The toxin caused lesions on a number of other monocots and dicots and proved to be non-host specific. This is the first report of the purification and characterization of S. oryzae toxin from in vitro and in vivo and we propose its name SO-toxin.     

A type II restriction endonuclease of Streptococcus thermophilus ST117

Three separate sets of polymerase chain reaction primers were designed to specifically detect the presence of a toxin A gene fragment, a toxin B gene fragment, and the entire toxin B gene. In addition toxin gene fragments that were amplified from well characterized toxic strains were tagged fluorescently and used as hybridization probes to screen C. difficile strains. A survey of 37 toxic strains and 10 non-toxic strains demonstrated that toxic strains normally contain the genetic composition for toxin A and toxin B simultaneously; whereas, non-toxic strains typically did not contain detectable toxin determinants. The only exception found was strain 39, which had the genetic composition for toxins A and B, but was not cytotoxic under the conditions tested.     

Sambutoxin, a new mycotoxin produced by toxic Fusarium isolates obtained from rotted potato tubers.

Ninety-nine isolates of Fusarium species were obtained from rotted potato tubers from various parts of Korea. Of these isolates, 80 were identified as Fusarium oxysporum, F. solani, or F. sambucinum. The isolates of these species were grown on autoclaved wheat grains and examined for toxicity in a rat-feeding test. A total of 8 of 57 F. oxysporum isolates, 3 of 14 F. solani isolates, and 5 of 9 F. sambucinum isolates caused the death of the rats. Of the 16 toxic isolates, 1 isolate of F. oxysporum produced a substantial amount of moniliformin, which could account for its toxicity. None of the other 15 isolates produced trichothecenes, moniliformin, fusarochromanone, fumonisin B1, or wortmannin. F. sambucinum PZF-4 produced an unknown toxin in wheat culture. This new toxin, given the trivial name sambutoxin, caused toxic effects in rats, including body weight loss, feed refusal, hemorrhage in the stomach and intestines, and, finally, death when rats were fed diets supplemented with 0.05 and 0.1% sambutoxin. The toxin was also toxic to chicken embryos, and the 50% lethal concentration was 29.6 micrograms per egg. Sambutoxin formed as white crystals that turned purple when combined with reagents such as sulfuric acid and p-anisaldehyde. It exhibited a green color immediately after treatment with potassium ferricyanide-ferric chloride. Its UV spectrum had absorption maxima at 213, 233, and 254 nm, and its infrared spectrum showed an amide group at 1,650 and 1,560 cm-1 and a hydroxy group at 3,185 cm-1. Mass spectrometry showed that the molecular weight of the toxin was 453 and the molecular formula was C28H39NO4.(ABSTRACT TRUNCATED AT 250 WORDS)     

Purification and some properties of Clostridium botulinum type AB toxin

Abstract The progenitor toxin of Clostridium botulinum type AB was purified; both large-sized (L) and medium-sized (M) toxins were found. The toxicity of M toxin increased by about 10-fold upon trypsinization; the increase was due mostly to type B toxin and a little to type A toxin. M toxin appeared to consist of one molecule each of toxic and nontoxic components. The activated toxic component was made up of four fragments, A-H- and L-chains and B-H- and L-chains. AB toxin may be a mixture of A and B toxins.     

Characterisation of hemolysis induced by T-2 toxin

The erythrocyte constitutes a good model system for the study of membrane-associated toxicity events caused by the trichothecene mycotoxin, T-2. This study confirms that T-2 has a direct lytic effect on erythrocytes. Lysis of guinea pig red cells requires approx. 10(10) molecules/cell and reaches plateau values after 4-6 h. An activation energy, Ea approximately equal to 4.5 kcal was derived from the Arrhenius equation. By use of osmotic blockers of differing Stokes' radii, the functional size of the membrane lesion caused by T-2 toxin was shown to be smaller than 5.5 A. It is concluded that T-2 toxin may exert its toxic effects via the cell membrane.     

Difficulties of molecular dissociation of Clostridium botulinum type G progenitor toxin

Clostridium botulinum type G progenitor toxin was chromatographed on DEAE-Sephadex and Q-Sepharose equilibrated with 0.05 M Tris-HCl buffer, pH 8.0, containing 0.2 M urea. The toxin was eluted in a single protein peak from DEAE-Sephadex, but it was eluted in four protein peaks from Q-Sepharose; the third peak was toxic and the others were nontoxic. The third peak, appearing to be the toxic component, had a molecular mass of 150,000. In SDS-polyacrylamide gel electrophoresis, purified type G progenitor toxin migrated in six bands, with molecular masses of 150,000, 140,000, 58,000, 10,800, 10,600, and 10,400. Type G progenitor toxin may be composed of a toxin component with a molecular mass of 150,000 and a nontoxic component in a manner similar to progenitor toxins of other types. Type G toxic component, whether it was reduced or not, migrated in a single band to the same relative positions in SDS-PAGE; type A toxic component reduced with 2-mercaptoethanol migrated in two bands.     

Staphylococcal toxin of toxic shock syndrome

Literature data on toxic shock syndrome staphylococcal toxin (TSST-1) are summarized; properties of Staphylococcus aureus strains producing TSST-1, nutrient media, and factors influencing on production of TSST-1 are reviewed. Physical and chemical properties of the toxin, its molecular characteristics, genetic regulation of its production, mechanism of action, and diseases which it causes are also discussed. Clinical and histologic signs of toxic shock syndrome (TSS), its diagnostic criteria, susceptibility of people to TSS, antigenic and serologic properties of the toxin, epidemiology of the infection caused by TSST-1-producing strains of staphylococci, methods of TSST-1 extraction and identification are described.     

A scorpion venom neurotoxin paralytic to insects that affects sodium current inactivation: purification, primary structure, and mode of action

A new toxin, Lqh alpha IT, which caused a unique mode of paralysis of blowfly larvae, was purified from the venom of the scorpion Leiurus quinquestriatus hebraeus, and its structural and pharmacological properties were compared to those of three other groups of neurotoxins found in Buthinae scorpion venoms. Like the excitatory and depressant insect-selective neurotoxins, Lqh alpha IT was highly toxic to insects, but it differed from these toxins in two important characteristics: (a) Lqh alpha IT lacked strict selectivity for insects; it was highly toxic to crustaceans and had a measurable but low toxicity to mice. (b) It did not displace an excitatory insect toxin, 125I-AaIT, from its binding sites in the insect neuronal membrane; this indicates that the binding sites for Lqh alpha IT are different from those shared by the excitatory and depressant toxins. However, in its primary structure and its effect on excitable tissues, Lqh alpha IT strongly resembled the well-characterized alpha scorpion toxins, which affect mammals. The amino acid sequence was identical with alpha toxin sequences in 55%-75% of positions. This degree of similarity is comparable to that seen among the alpha toxins themselves. Voltage- and current-clamp studies showed that Lqh alpha IT caused an extreme prolongation of the action potential in both cockroach giant axon and rat skeletal muscle preparations as a result of the slowing and incomplete inactivation of the sodium currents. These observations indicate that Lqh alpha IT is an alpha toxin which acts on insect sodium channels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Isolation and some properties of ciguatoxin

Ciguatoxin, the principal toxin of ciguatera produced by a toxic dinoflagellate and accumulated through the food chain in the viscera of moray eels, was purified. The probable molecular formula C₆₀H₈₆O₁₉ was obtained for the first time by high resolution mass spectrometry. ¹H NMR spectra suggested the presence of a primary hydroxyl group suitable for preparing an antigen necessary to develop an enzyme immunoassay. author for correspondence     

Toxin profile of Alexandrium catenella from the Chilean coast as determined by liquid chromatography with fluorescence detection and liquid chromatography coupled with tandem mass spectrometry

The profile of tetrahydropurine neurotoxins associated with paralytic shellfish poisoning (PSP) was determined from a Chilean strain of the marine dinoflagellate Alexandrium catenella. The toxin composition was compared with that of toxic shellfish, presumably contaminated by natural blooms of A. catenella from the same region in southern Chile. Ion pair-liquid chromatography with post-column derivatization and fluorescence detection (LC-FD) was employed for relative quantitative analysis of the toxin components, whereas unambiguous identification of the toxins was confirmed by tandem mass spectrometry (LC–MS/MS). In the dinoflagellate strain from Chile, the N-sulfocarbamoyl derivatives (C1/C2, B1) and the carbamoyl gonyautoxins GTX1/GTX4 comprise >90% of the total PSP toxin content on a molar basis. This toxin composition is consistent with that determined for A. catenella populations from the Pacific coast in the northern hemisphere. The characteristic toxin profile is also reflected in the shellfish, but with evidence of epimerization and metabolic transformations of C1 and C2 to GTX2 and GTX3, respectively. This work represents the first unequivocal identification and confirmation of such PSP toxin components from the Chilean coast.     

Effect on sphingomyelin-containing liposomes of phospholipase D from Corynebacterium ovis and the cytolysin from Stoichactis helianthus

The toxic, sphingomyelin-specific phospholipase D (phosphatidylcholine phosphatidohydrolase EC 3.1.4.4) from Corynebacterium ovis was purified to near homogeneity. It has a molecular weight of 31 000 and a pI of approx. 9.8. Although not cytolytic itself, it protected red cells from hemolysis by staphylococcal sphingomyelinase (beta-hemolysin) and helianthus toxin. The apparently non-enzymatic cytolysin (helianthus toxin) from the sea anemone Stoichactis helianthus also interacts with membrane sphingomyelin. C. ovis and helianthus toxins were compared with regard to their effects on liposome model membranes, and they were found both to produce changes analogous to those in erythrocytes. Only helianthus toxin caused release of trapped glucose marker, but liposomes could be protected from release by pretreatment with C. ovis toxin. Both toxins demonstrated binding to sphingomyelin-containing liposomes, but only the bacterial sphingomyelinase catalyzed the release of choline from these vesicles.     

Purification and chemical characterization of the major neurotoxin from the venom of Pelamis plautrus.

A major toxin was isolated from the venom of the sea snake Pelamis platurus (yellow-bellied sea snake) by Sephadex G-50 and carboxymethylcellulose column chromatography. The LD50 of the pure toxin (Pelamis toxin a) was 0.044 mug/g in mice representing a tenfold increase in toxicity after purification. The toxin was homogeneous in acrylamide disc gel electrophoresis and eluted as a single peak after isoelectric focusing in a sucrose density gradient column. The isoelectric point was 9.69; thus it is a highly basic protein. The toxin contained 55 amino acid residues with four disulfide linkages. When all disulfide linkages were reduced and alkylated, the toxic action of the pure toxin disappeared leading to the conclusion that the disulfide bonds of the neurotoxin were essential for toxic action.     

Heat-labile toxin-producing isolates of Pasteurella multocida from rabbits.

Five of one hundred forty seven isolates of Pasteurella multocida from rabbits were found to produce heat-labile toxin. Each isolate was assayed for the ability of potassium thiocyanate (KSCN) extracts to cause dermonecrosis in guinea pig skin, ability of bacteria or filtrates to cause cytotoxicity in cell cultures, and reactivity with monoclonal antibodies to heat-labile P. multocida toxin. Five capsular type D isolates produced dermonecrosis and reacted with monoclonal antibodies to toxin. Filtrates of all five of these isolates were cytotoxic for cell cultures. Potassium thiocyanate extracts of all five isolates caused pleuritis and pneumonia in rabbits after intranasal inoculation. Turbinate atrophy was seen in 5 of 19 rabbits inoculated intranasally with toxic extracts. Heat-labile toxin was not produced by 109 capsular type A isolates or 19 nontypable isolates.     

The effects of purified pertussis components and lipopolysaccharide on the results of the mouse weight gain test

The effects of highly purified components of Bordetella pertussis, that is pertussis toxin (PT) and filamentous haemagglutinin (FHA), and of lipopolysaccharide (LPS) were studied in the active mouse weight gain test (MWGT). The PT when given alone or with other components in various combinations caused weight losses and deaths 2-3 days after inoculation but FHA was not toxic in the MWGT. When FHA was given with PT, the toxic effect of PT was reduced. The LPS caused weight losses at 24 h which decreased when LPS was given with PT. The toxic effects of PT as indicated by late deaths and late weight losses or failure to gain weight continued until 14 days after inoculation. The various components had similar effects on mouse weight gain in both LACA and NIH strains of mice. The doses of PT used in the MWGT caused marked leucocytosis but FHA and LPS did not. No agglutinins appeared in the sera of mice inoculated with various purified components. The components were thus pure and did not contain agglutinogens.