Journal of natural toxins最新文献

A three-year surveillance program assessed the extent of mycotoxin contamination of key foods and feeds grown in Bangladesh. The study also included groundnuts utilized as snack food. In the first two phases of the program the samples collected were analyzed only for aflatoxins, but in the third phase, as well as for aflatoxins, samples were tested for the presence of fumonisin B1, ochratoxin A, zearalenone, deoxynivalenol, and T-2 toxin. Of the foods and feeds tested, the incidence of aflatoxin contamination varied from low (rice collected from farmers' stores, 8%) to high (maize, 67%). However, both the average total aflatoxin contents (< 1.0 microg/kg) and the maximum aflatoxin B1 contents (< or = 5.0 microg/kg) recorded for pulses, rice and its various products, and wheat were low. On the other hand, the levels of contamination of maize, roasted and raw groundnuts, and poultry feed were considerably higher, with average total aflatoxin B1 contents of 33, 13, 65, and 7 microg/kg, respectively, and maximum aflatoxin B1 contents of 245, 79, 480, and 160 microg/kg, respectively. Fumonisin B1, ochratoxin A, zearalenone, deoxynivalenol, and T-2 toxin were found, to any significant extent, only in some of the maize samples tested, always accompanied by aflatoxins. One sample of maize contained five mycotoxins, namely, the aflatoxins, fumonisin B1, deoxynivalenol, zearalenone, and ochratoxin A. In a limited trial using hospital staff in Dhaka, the analysis of the aflatoxin-albumin adduct in serum showed that approximately half of the test group had been recently exposed to low levels of aflatoxins.

Quantitative determination of newly reported enzymes activity in the crude skin toxin (CST) of catfish revealed highest activities of hyaluronidase and lipase, lesser activities of phospholipase A2, lactate dehydrogenase (LDH), cholinesterase (CE), alkaline phosphatase (ALP), and aspartate transaminase (AST), and least activities of proteinase and 5-nucleotidase (5'-NT). The CST has a hemolytic activity of 54% and no ichthyotoxicity up to 500 ug/ml. The chosen dose of CST (LD12.5) showed a potential cytotoxic activity against solid Ehrlich carcinoma-bearing mice demonstrated by an increase in the mean survival time (238.8%) and tumor growth inhibition ratio (T/C) of 73%. The CST ameliorated the relative weights of heart and liver after three weeks, while modulating the elevation in the relative spleen weight throughout the treatment periods (three, six, and nine weeks). The levels of serum triglyceride, total cholesterol, and liver total lipids were normalized after three weeks, whereas the serum albumin and hepatic glycogen concentrations, as well as ALT, AST, 5'-NT, and G-6-Pase activities were ameliorated after 6 weeks. Serum levels of glucose, LDH, and creatine kinase (CK) activities were significantly modulated throughout the treatment periods. Histological examinations of the tumor and liver tissues of treated tumor-bearing animals were carried out. Tumor tissues showed many cytolytic and cytopathic changes after treatment, while liver tissues showed moderate dysplastic changes after six weeks of treatment, which became more marked after nine weeks.

The presence of nerve growth factor (NGF) is reported in salivary glands of mice and sex organs of various male animals. NGF level is reported to be higher in salivary glands of male mice in comparison to female. This investigation reports the presence of NGF in major organs of Balb/c mice showing quantitative differences in NGF according to sex and age. Organs of Balb/c mice from ages 2 weeks to 9 months were tested for NGF content by immunological tests enzyme-linked immunosorbent assay (ELISA). Male and female mice for each age group were from the same litter. It was revealed that NGF levels increased with age, reaching the peak at 4 weeks for male mice versus 3 months for female for similar organs. There were consistently lower levels of NGF in the organs of female mice in comparison to their male siblings. Most decreased levels of NGF were observed in organs of mice with respect to heart, salivary glands, and sex organs, ovaries versus testes. The presence of NGF was further revealed in non-neural organs. NGF based maturity was reached at 4 months for male mice versus 6 months for females.

An L-amino acid oxidase (LAO), designated as TJ-LAO, was purified to homogeneity from the venom of Trimeresurus jerdonii by Sephadex G-100 and Q Sepharose HP chromatography. The molecular weight of this enzyme was 110 kD as estimated by analytical gel filtration and was 55 kD by SDS-polyacrylamide gel electrophoresis, suggesting that the enzyme is composed of two subunits. The enzyme has an absorption spectrum characteristic of flavoproteins, containing 2 moles of FMN per mole of enzyme. The N-terminal sequence of TJ-LAO shares high homology with other viperid snake venom LAOs. Homology with elapid venom LAO is lower. TJ-LAO inhibited the growth of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus megaterium. The antibacterial effect associated with LAO activity was elminated with the addition of catalase. Platelets in platelet-rich plasma aggregated upon the addition of TJ-LAO. The enzyme-induced aggregation was inhibited by catalase, suggesting formation of H2O2 was essential for TJ-LAO to induce platelet aggregation. These results showed H2O2 formation is important for the biological effects of LAO.

Heptyl prodigiosin was purified from a culture of alpha-proteobacteria isolated from a marine tunicate collected in Zamboanga, Philippines, as part of a program to screen natural products for antiparasitic activity. An in vitro antimalarial activity similar to that of quinine was found against the chloroquine-sensitive strain Plasmodium falciparum 3D7. The in vitro antimalarial activity was about 20 times the in vitro cytotoxic activity against L5178Y mouse lymphocytes. A single subcutaneous administration of 5 and 20 mg/kg significantly extended survival of P. berghei ANKA strain-infected mice but also caused sclerotic lesions at the site of injection. A single administration by gavage of 50 mg/kg did not increase survival time. The compound was not found to be mutagenic using in vitro micromethods for the Ames Salmonella typhimurium assay and the micronucleus assay using L5178Y mouse lymphoma cells.

Venom proteins from the dorsal spine of two scorpionfish, Hypodytes rubripinnis and Synanceia verrucosa were assayed for mitogenicity and cytotoxicity. The two venoms had both mitogenic and cytotoxic activity on murine splenocytes and murine P388 leukemic cells. In H. rubripinnis, the second gel chromatographic fraction showed cytotoxic activity on P388 leukemic cells. On native PAGE, the glycoprotein isolated by concavalin A sepharose chromatography appeared to have a molecular mass of 110 kDa. In addition, two D-galactose-binding lectins (SUL-I and SUL-II) and a heparin-binding lectin (TGL-I) were purified from the globiferous pedicellariae of the toxopneustid sea urchins, Toxopneustes pileolus and Tripneustes gratilla, respectively. SUL-I (Nakagawa et al., 1999a) had mitogenic activity and cytotoxic activity but SUL-II and TGL-I did not. SUL-I did not show sequence homology to SUL-II. A hemolytic lectin with a molecular mass of 29 kDa was isolated from the coelomic fluid of T. gratilla. The hemolytic activity of the lectin was dependent on Ca2+ concentration and inhibited by lactose. The present results suggest that some species of scorpionfish and sea urchins may be novel sources for biologically active substances such as anti-tumor compounds or new lectins.

This study was performed to assess the ability of polyvalent snake venom anti-serum, produced by the Egyptian Organization for Biological Products & Vaccines (VACSERA), to neutralize several toxic activities of snake venoms, not only of those included in the antivenom mixture, but also some additional venoms of snakes from Egyptian, African, and Middle Eastern habitats. In general, the results revealed that polyvalent snake venom anti-serum from VACSERA is highly effective in neutralizing Egyptian snake venoms, especially Naja haje, Naja nigricolles, Naja pallida, Cerastes cerastes, Cerastes cerastes cerastes, Cerastes vipera, Pseudocerastes persicus fieldi, and Walterinnisia egyptia. The antivenom was also effective against Naja haje, Walterinnisia egyptia, and Bites aritans from Saudi Arabia. High activity was obtained against venoms from Naja haje, Naja nigricolles, and Naja pallida of Sudan, as well as the African Naja melanoleuca, Naja mossambica, Naja naja oxiana, Bites gabonica, and Vipera lebetina. Only moderate effectiveness was obtained with Echis coloratus and Echis carinatus, and the polyvalent antiserum was ineffective against the venom of Naja nivea.

Among several batches of clams harvested in Tunisia and imported to France, a small number of them were found to be neurotoxic to mice (intraperitoneal injection) as determined by the diarrhetic shellfish poisoning (DSP) bioassay developed by Yasumoto et al. (1978). The present study was conducted to confirm the nature of the toxic agent, suspected to be gymnodimine. Liquid chromatography tandem mass spectrometry analyses unequivocally revealed the presence of gymnodimine in the shellfish, making Tunisia the second country, after New Zealand, where shellfish contamination with this phycotoxin is reported. Gymnodimine B and C analogues were not detected in the clam samples. Gymnodimine preferentially accumulates in the digestive gland of the Tunisian clams, although substantial amounts are also found in the meat.

Attempts were made to elucidate the different responses of shellfish to paralytic shellfish poison (PSP) and the PSP donor Alexandrium minutum T1. Five species of edible bivalves (Crassostrea gigas, Meretrix lusoria, Mytilus edulis, Ruditapes philippinarum, and Soletellina diphos) were collected and examined for susceptibility to PSP and PSP donor. It was determined that all five bivalves had low susceptibility to PSP following an intramuscular injection (> 300 MU/20 g). The abnormal effects on bivalves were species-specific and varied with the concentration of A. minutum T1. Judging from the LC50 data (medium lethal concentration), the resistance of bivalves to the toxic dinoflagellate was as follows (least to most resistant): C. gigas < R. philippinarum < M. lusoria < M. edulis, S. diphos. With the exception of S. diphos, the bivalves accumulated very little toxin (< 2 MU/g edible tissue) when they were exposed to 10(7) cells/L of A. minutum for four days. The toxin levels in S. diphos increased with exposure time to the toxic dinoflagellates and accumulated primarily in the digestive gland (88-100%), followed by the gill (0-10%), and other organs (0-8%). Although the concentrations of toxin components in the digestive gland were found to be variable during the exposure period, the toxin profile in the digestive gland of S. diphos during the early exposure period was similar to that of A. minutum. Moreover, toxin components in the gills and in other organs were retained at near constant concentrations during the exposure period.