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PubMed1986

Minimal moisture content for growth and aflatoxin production by Aspergillus parasiticus in mixed feeds.

Minimal moisture content for growth and aflatoxin production by Aspergillus parasiticus in mixed feeds was studied. Minimal moisture content for growth is 16.51% +/- 0.45. Very low amounts of aflatoxins are accumulated at days 1 or 2 after the growth started when the initial moisture content of the mixed feed was 17% or lower; on the other hand, significant amounts of aflatoxin are detected when it was 18% or higher.

Aflatoxins↗
PubMed1992

Effect of dietary aflatoxin B1 on the growth response and haematologic changes of young Japanese quail.

Feeding of aflatoxin B1 at the rate of 0.5 ppm to young Japanese quail resulted in significant (p less than 0.01) decrease in body weight gain that became apparent on the third week. There was no significant difference in the mean values of haemoglobin, packed cell volume and total erythrocyte counts of quail chicks given aflatoxin B1 in feed in comparison to those fed on a similar diet without aflatoxin. However, the total leucocyte count revealed an increase on the third week which was due to an increase in the percentage of heterophils and decrease in lymphocytes.

Aflatoxin B1↗
PubMed1989

Effects of cyclopiazonic acid and aflatoxin singly and in combination on selected clinical, pathological and immunological responses of guinea pigs.

Cyclopiazonic acid (CPA) and aflatoxin are known sometimes to coexist in nature but little is known of possible biological interaction in mammals that consume mixtures of these two mycotoxins. Guinea pigs were dosed orally with CPA (2.2 mg/kg) or aflatoxin (0.045 mg B1/kg) singly or in combination. Effects of toxin consumption were determined on clinical health, body weight gain, pathological change, and several immunologically related parameters including delayed cutaneous hypersensitivity, antibody response, complement hemolytic titer, intracutaneous mitogen (PHA) and in vitro lymphocyte blastogenesis. In contrast to an earlier study by others, significant synergy between these two toxins was demonstrated in reduced rate of body weight gain, lethality and histologic changes (vacuolization) in hepatocytes. Reductions in complement titer, intradermal PHA, delayed cutaneous hypersensitivity response and in vitro lymphocyte blastogenesis were related to aflatin activity. No effects on antibody formation to Brucella abortus were observed with either toxin or the combination of toxins. Cyclopiazonic acid appeared to restore the suppressive effects of aflatoxin in delayed cutaneous hypersensitivity response and in vitro lymphocyte blastogenesis.

Administration, Oral↗
PubMed1988

Isolation of aflatoxin from Acacia and the incidence of Aspergillus flavus in the Sudan.

A total of 1300 seeds from 13 commodities were surveyed for Aspergillus flavus. An additional inoculum was obtained from 6 divergent sources. A. flavus isolants, randomly selected on the bases of visual cultural characteristics and inoculum source, were assayed for aflatoxin yielding capacity. Out of 97 analyzed isolates 76 (78.3%) were aflatoxin-elaborators of which 27 (27.8%) colonies were classified as very highly toxinogenic (greater than 1000 micrograms/kg). Acacia, described a new source of aflatoxin (81 to greater than 1000 micrograms/kg), is herein first described from Sudan as a substrate for A. flavus.

Acacia↗
PubMed1986

Substrate depletion during formation of aflatoxin and kojic acid on corn inoculated with Aspergillus flavus.

Depletion of sugar and starch carbon sources and concomitant formation of secondary fungal metabolites, aflatoxin and kojic acid, were examined in growing corn inoculated with Aspergillus flavus. Kernels from control and inoculated ears were removed and analyzed after 16, 24, 48, 96 and 168 hrs. Reducing sugars were not significantly different for inoculated and control non-inoculated samples, but after 168 hrs (seven days) starch content was 20% lower in inoculated than in control samples. Kojic acid was detected before aflatoxins formed. Kojic acid, the oxidized product of kojic acid, and aflatoxin were all present in samples two days from inoculation. The formation of this oxidation product may influence toxin levels.

Aflatoxins↗
PubMed1980

Aspergillus growth and aflatoxin production on black pepper.

Black peppercorns supported the growth of Aspergillus parasiticus (flavus) NRRL 3145. Incubation at 28 C and RH of 85% for 30 days resulted in profuse conidial production on the reticulate ridges of the peppercorns. An SEM study of these ridges showed that they were cortical eruptions, and the particulate matter present favored mycelial establishment. Hyphal anastamoses were commonly observed. Following this incubation the inoculated peppercorns were stored in the dark at room temperature and ambient humidity for 15 days. Aflatoxin was detected on minicolumn. Aflatoxin B1 was produced at levels of 60 micrograms/kg with traces of aflatoxin B2, G1 and G2. Quantitative estimation was based on a visual comparison with standards by thin-layer chromatography.

Aflatoxins↗
PubMed1989

Interrelationship of kernel water activity, soil temperature, maturity, and phytoalexin production in preharvest aflatoxin contamination of drought-stressed peanuts.

Samples of Florunner peanuts were collected throughout a period of late-season drought stress with mean geocarposphere temperatures of 29 and 25 degrees C, and determinations of maturity, kernel water activity (aw), percent moisture, capacity for phytoalexin production, and aflatoxin contamination were made. Results showed an association between the loss of the capacity of kernels to produce phytoalexins and the appearance of aflatoxin contamination. Kernel aw appeared to be the most important factor controlling the capacity of kernels to produce phytoalexins. Mature peanuts possessed additional resistance to contamination that could not be attributed solely to phytoalexin production. Kernel moisture loss was accelerated in the 29 degrees C treatment compared to the 25 degrees C treatment, and data indicated that the higher soil temperature also favored growth and aflatoxin production by Aspergillus flavus in peanuts susceptible to contamination.

Aflatoxins↗
PubMed1977

Aflatoxin production by Aspergillus parasiticus in a competitive environment.

Aspergillus parasiticus NRRL 2999 was grown in the presence of Rhizopus nigricans, Saccharomyces cerevisiae, Acetobacter aceti, or Brevibacterium linens and aflatoxin concentration was determined after 3,5,7, and 10 days of incubation at 28C. R. nigricans and S. cerevisiae inhibited growth and aflatoxin production by A. parasiticus. B. linens caused slight inhibition and A. aceti stimulated growth and aflatoxin production by A. parasiticus.

Acetobacter↗
PubMed1980

Morphological changes in strains of Aspergillus flavus Link ex Fries and Aspergillus parasiticus Speare related with aflatoxin production.

Two strains of Aspergillus flavus Link ex Fr. and two strains of A. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pané no. 257) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.) The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied, A. flavus NRRL 3251, lost completely the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations. A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.

Aflatoxins↗
PubMed1989

Relationship between lipids and aflatoxin biosynthesis.

This paper describes the key role of lipids on fungal growth and of lipoperoxidation on the output of aflatoxin biosynthesis both 'in vitro' and 'in vivo'. 'In vitro' BHA, BHT and cysteamine, depending their concentration, are capable of reducing or blocking aflatoxin output induced by lipoperoxides or halomethanes in cultures of Aspergillus flavus or A. parasiticus without affecting fungal growth. 'In vivo' BHA and BHT significantly reduced aflatoxin production on wheat, maize and sunflower inoculated with aflatoxigenic Aspergilli essentially by preventing fungal growth. 'In vivo' the seeds surface lipids represent a very important carbon source for fungal growth.

Aflatoxins↗
PubMed1991

Aspergillus flavus and aflatoxins B1, B2, and M1 in corn associated with equine death.

Corn from an Arkansas farm, where three horses died and others became sick, was investigated for causative principles. Necropsy of the three horses revealed what appeared to be severe hepatic necrosis. Histopathological examination indicated a pattern of hepatic lesions that was suggestive of aflatoxin contamination of the feed. Mycological examination of the corn by dilution plating revealed 95% of the colonies as Aspergillus flavus. Chemical analysis of the corn for mycotoxins was positive for aflatoxin B1, B2, and M1 at concentrations of 114, 10, and 6 micrograms/Kg, respectively. Cyclopiazonic acid, sterigmatocystin, and the Fusarium toxins, vomitoxin (deoxynivalenol), T-2 toxin, and diacetoxyscirpenol, were not detected. The presence of aflatoxin metabolites in the moldy corn and the presence of appropriate lesions were compatible with the diagnosis, equine aflatoxicosis.

Aflatoxins↗
PubMed1989

Aflatoxin levels in foodstuffs in Fiji and Tonga islands.

Fungal growth is a major problem of food storage in humid environments, as occur in South Pacific countries for parts of the year. Major crops, including edible nuts, copra and root crops, are susceptible to Aspergillus growth and therefore potential contamination with aflatoxin. Liver cancer occurs in Fiji and Tonga, with the occurrence in Fijians being significantly higher than in the Indian population. Thirty-three peanut samples from farmers were analysed for aflatoxin and 50% of the samples from Fiji were positive but only 9% from Tonga, reflecting different storage practices. Local copra, cassava, and maize samples were found contaminated, with only the maize at a serious level. Twenty-five plate food samples from Fiji showed low contamination. When starch foods from the Fijian diet left after cooking were analysed to follow potential aflatoxin development only sweet potatoes showed some contamination.

Aflatoxins↗
PubMed1995

Ochratoxin A and aflatoxins in breast milk samples from Sierra Leone.

Breast milk from 113 mothers in two 'Under-Five Clinics' in the Southern Province of Sierra Leone, namely, Njala and Bo, were examined for their mycotoxin content. Only 10 were mycotoxin-free. Eighty-eight per cent of samples contained various aflatoxins and 35% contained ochratoxin A (OTA). Few samples (15%) had a single mycotoxin. Thirty-six (32%) had two mycotoxins and 50 (40%) had three or more. The occurrence of OTA in combination with various aflatoxins was recorded. It is concluded that infants in Sierra Leone are exposed to OTA and aflatoxins at levels which in some cases far exceed those permissible in animal feed in developed countries.

Aflatoxins↗
PubMed1994

Ultrastructural changes in murine lymphocytes induced by aflatoxin B1.

This investigation sought to determine whether splenic lymphocytes obtained from Balb/C mice exposed to aflatoxin B1 (AFB1) showed any ultrastructural changes which could account for the immunodysfunction attributable to aflatoxins. Lymphocytes obtained from Balb/C mice administered aflatoxin B1 in olive oil daily for three weeks were studied using both transmission and scanning electron microscopy. The lymphocytes demonstrated ultrastructural changes primarily in the mitochondria where marked internal dissociation of the cristae was revealed by transmission electron microscopy. All other cellular organelles were unaffected. No significant alterations in external structure were observed under scanning electron microscopy. The findings of this study indicate that AFB1 administration does not affect the surface topography of lymphocytes, but AFB1, by causing extensive mitochondrial damage, may affect the way in which these cells function. This could be a possible explanation for the immunodysfunction associated with AFB1.

Aflatoxin B1↗
PubMedDate not supplied

Mycoflora and aflatoxin production in pigeon pea stored in jute sacks and iron bins.

The mycoflora, moisture content and aflatoxin contamination of pigeon pea (Cajanus cajan (L.) Millisp) stored in jute sacks and iron bins were determined at monthly intervals for a year. The predominant fungi on freshly harvested seeds were Alternaria spp., Botryodiplodia theobromae, Fusarium spp. and Phoma spp. These fungi gradually disappeared from stored seeds with time and by 5-6 months, most were not isolated. The fungi that succeeded the initially dominant ones were mainly members of the general Aspergillus, Penicillium and Rhizopus. Population of these fungi increased up to the end of one year storage. Higher incidence of mycoflora and Aspergillus flavus were recorded in jute-sack samples throughout the storage period. The moisture content of stored seeds was found to fluctuate with the prevailing weather conditions, being low during the dry season and slightly high during the wet season. The stored seeds were free of aflatoxins for 3 and 5 months in jute sacks and iron bins respectively. The level of aflatoxins detected in jute-sack storage system was considerably higher than that occurring in the iron bin system. Of 196 isolates of A. flavus screened, 48% were toxigenic in liquid culture (54% from jute sacks and 41% from iron bins).

Aflatoxins↗
PubMed1976

Formation of a derivative of aflatoxin B1 on a sephadex column with a 1% aqueous solution of methanol.

A PARTIAL SEPARATION OF AFLATOXINS B1 and B2 on a Sephadex column with a 1% aqueous solution of methanol as mobile phase was achieved. The chromatographic system is, however, not neutral for aflatoxin B1. During elution a derivative--probably aflatoxin B1 hemiacetal-is produced. The derivative forms blue fluorescent spots on Adsorbosil-1 plates with Rf 0.15 when developed in chloroform/acetone (90 + 10).

Aflatoxins↗
PubMed1975

Studies on the recovery of aflatoxin b1 injected into frozen beef at different intervals of storage.

Beef stored at --18 degrees C for 20,25,32,153, and 183 days showed a diminution in the recovery of injected aflatoxin B1. An unusual passing of aflatoxin in ether and hexane fractions of silica gel column was noted. Ether fraction contained aflatoxin B1-like substance from stored beef samples. Probable occlusion of aflaton B1 to meat constituents due to physico-chemical changes associated with muscle during storage was discussed.

Aflatoxins↗