ISSN:1056-9014    

DOI:10.1002/nt.2620010102

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

ISSN:1056-9014    

DOI:10.1002/nt.2620010103

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractAdditional bioactive Annonaceous acetogenins have been isolated from the EtOH extract of the bark ofAnnona bullataRich. by bioactivity‐directed fractionation using lethality to brine shrimp. These acetogenins include bullatencin, a new single tetrahydrofuran acetogenin having a double bond in the hydrocarbon chain; 4‐deoxyasimicin, a new adjacent bis‐tetrahydrofuran acetogenin; and the uvariamicins, an isomeric mixture of four single tetrahydrofuran acetogenins. These acetogenins showed selective cytotoxicities for certain human solid tumor cell lines comparable to or better than adriamycin. © 1992 Wiley‐L

ISSN:1056-9014    

DOI:10.1002/nt.2620010104

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractAn in vitro peripheral lymphocyte blastogenesis system was used to investigate the biological activities of the fungal toxin fusarochromanone (TDP‐1) and its monoacetyl derivative TDP‐2. Briefly, cultures of human or bovine peripheral lymphocytes were exposed to TDP‐1 or TDP‐2 and a mitogen (PHA, Con A or PWM). After a standard incubation time, cell proliferation was quantified using the MTT bioassay. Human and bovine lymphocyte proliferation was inhibited by high concentrations of TDP‐1; however, bovine lymphocyte proliferation was significantly increased at low concentrations of TDP‐1. TDP‐2 has similar but less pronounced effects on lymphocyte proliferation. © 1992 W

ISSN:1056-9014    

DOI:10.1002/nt.2620010105

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractAfter repeated ip and oral administrations of ciguatoxin (CTX) and ciguatoxin‐4c (CTX‐4c), one of the derivatives of CTX, to male ICR mice at a dose of 0.1 μg/kg for 15 days, resulted in marked swelling of cardiac cells and endothelial lining cells of blood capillaries in the heart was observed. Single doses caused no discernible pathological changes. Damage to the capillaries was followed by prominent effusion of serum and erythrocytes into the interstitial spaces of the myocardium occurred. Swelling of the endothelial lining cells of capillaries caused narrowing of the lumen and accumulation of blood platelets in capillaries, which resulted in multiple single cell necroses of cardiac muscle cells. Within 1 month after the treatments of these phycotoxins, myocytes and capillaries appeared to be normal. Effusion in the interstitial spaces resulted in formation of bundles of dense collagen, which persisted for 14 months. Diffuse interstitial fibrosis was prominent in septum and ventricles, accompanied by bilateral ventricular hypertrophy. A single dose of 0.7 μg/kg ip resulted in severe acute heart injuries, followed by diffuse myocardial fibrosis. © 1992 Wiley‐L

ISSN:1056-9014    

DOI:10.1002/nt.2620010106

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractBy an introduction of sodium dodecylsulfate for cell lysis and immunomicroplate for mass assay, the modified SOS microplate assay method was established and applied for the evaluation of genotoxicity of mycotoxins and fungal cultures. Among 20 mycotoxins, the carcinogenic dihydrobisfuranoids such as aflatoxin B1, sterigmatocystin, and versicolorin A were positive in the presence of the activation system. While, the carcinogenic anthraquinones and lactones such as luteoskyrin, rugulosin, ochratoxin A, patulin, and citrinin were negative. The survey on genotoxic fungi revealed that, among 15 fungal isolatesAspergillus versicolor, Emericella acristata, and others were positive. Additional survey on 265 fungal isolates have revealed that variousAspergillusgenera such asA. flavus, A. parasiticus, A. ustus, A. nidulans, and others were positive for SOS induction, along with several isolates ofFusarium moniliforme. The chemical analysis revealed that the dihydrobisfuranoids such as aflatoxin B1, and sterigmatocystin were the major genotoxic metabolites of severalAspergillusspecies. The SOS microplate assay system is a simple and rapid procedure for the mass screening of genotoxic fungi, particularly of the dihydrobisfuranoids‐producing strains. © 1992 Wiley‐Liss,

ISSN:1056-9014    

DOI:10.1002/nt.2620010107

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractTwo toxic pyrrolizidine alkaloids were isolated fromMelampyrum pratenseand their structures determined by spectroscopic methods. © 1992 Wiley‐Liss, I

ISSN:1056-9014    

DOI:10.1002/nt.2620010108

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe interactive effect of the combinations of trichothecene mycotoxins often found in fungus infected plants, contaminated grain, and other biological systems is poorly understood. Growth inhibition of the yeastKluyveromyces marxianuswas used to measure the effects of HT‐2 toxin, roridin A, and T‐2 toxin as individual toxins or as binary mixtures. A value, the combination index, was derived which indicates the interactive effects of a binary mixture of toxins. The interaction is affected by the ratio of the individual toxins, and the percent inhibition of yeast growth. Generally the interaction of T‐2 toxin and roridin A or T‐2 toxin and HT‐2 toxin changes from antagonistic when they cause a low percent inhibition of yeast growth to synergistic when they cause a high percent inhibition of yeast growth. Additionally, any two trichothecenes have a unique ratio, which we name the maximally quiescent ratio (or MQR), where there is the least change in the type and intensity of their interaction. The maximally quiescent ratio in this case has helped to define the nature of toxin interactions and could be used to provide insights into hormone, immune system, developmental, enzyme, and gene regulation, combined drug therapy, and the action of mixtures of natural or synthetic toxins, carcinogens, pesticides, and environmental pollutants. © 1992 Wiley

ISSN:1056-9014    

DOI:10.1002/nt.2620010109

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe decomposition process of toxic blue‐green alga (cyanobacteria),Microcystis aeruginosa, under dark and aerobic condition was investigated in relation to the change of the amounts of heptapeptide toxins (microcystins YR and LR) by two experiments: one withMicrocystiscells and the other with two purified microcystins. In the experiment withMicrocystiscells, an increase of heterotrophic bacteria observed from the beginning of the experiment, was followed by decomposition of the algal cells and the subsequent release of microcystins into the filtrate fraction. The amounts of the toxins initially present in the cells were quantitatively detected in the filtrate fraction on the 35th day. The decomposition of microcystin YR began on the 42nd day. The decomposition rate of the two toxins was different. The decomposition rate of purified microcystins YR and LR, compared in distilled water and culture medium, respectively, indicated clearly that microcystin YR was more labile to decomposition than microcystin LR in the culture medium. At the end of the experiment (45th day) microcystin YR decreased to 58.6%, while 86.2% of microcystin LR remained. © 1992 Wiley‐Liss,

ISSN:1056-9014    

DOI:10.1002/nt.2620010110

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractSome biological and neurochemical properties of the venom of stonefish (Syanceja horrida) were investigated. The venom exhibited oedema‐inducing, haemolytic, hyaluronidase, thrombin‐like, alkaline phosphomonoesterase, 5′ nucleotidase, acetylcholinesterase, phosphodiesterase, arginine esterase, and arginine amidase activities. Recalcification clotting time, prothrombin, and kaolin‐cephalin clotting times were increased 1.7–2.3‐ and 2.4‐fold respectively. The LD50(i.v. mouse) was 300 μg/Kg. Its effects on uptake and stimulation of neurotransmitter synthesis and release were observed in rat brain synaptosomes. In the presence of 100 μg venom, uptake of [methyl‐3H] choline in rat brain synaptosomes was inhibited 70%, while that of 4‐amino‐n‐[U‐14C] butyric acid was inhibited 20%. The toxin also stimulated the release of [3H]‐acetylcholine from the synaptoso

ISSN:1056-9014    

DOI:10.1002/nt.2620010111

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY