Assessment of wood-inhabiting Basidiomycetes for biokraft pulping of softwood chips.

Wood-inhabiting Basidiomycetes have been screened for various applications in the pulp and paper industry and it is evident that different fungi need to be used to suit the specific requirements of each application. This study assessed the suitability of 278 strains of South African wood-decay fungi for the pre-treatment of softwood chips for kraft pulping. The influence of these fungi on kappa number, yield and strength properties of pulp was evaluated.

Enumeration of fungi in barley.

Estimation of fungal contamination of barley grain is important as certain fungi can proliferate during the malting process. The following factors which may affect the enumeration of fungi were evaluated: dilution versus direct plating, presoaked versus unsoaked grain, five culture media: potato dextrose agar (PDA), acidified Czapek-Dox agar (ACA), pentachloronitrobenzene agar; (PCNB) dichloran rose bengal chloramphenicol agar (DRBC) and malt salt agar; two disinfectants' ethanol/water (80:20 v/v) and sodium hypochlorite (3.5% w/v in H2O).

Perinatal mortality in lambs of ewes exposed to cultures of Diplodia maydis (= Stenocarpella maydis) during gestation.

During 1987 when cob rot was rife, perinatal losses were reported in flocks and herds that had been exposed to diplodiosis. The affected lambs or calves were either stillborn or died soon after birth. Dosing trials at the Onderstepoort Veterinary Research Institute involving 82 ewes revealed that 66% of the offspring of dams exposed to cultures of Diplodia maydis (= Stenocarpella maydis) in the second trimester of pregnancy and 87% of lambs of ewes exposed in the third trimester were born dead or died soon afterwards.

Mycotoxic peripheral myelinopathy, myopathy, and hepatitis caused by Diplodia maydis in vervet monkeys.

During recent historical times many Africans changed their diet to one based on maize. The grain is regularly contaminated by fungi which are toxigenic to domestic animals and birds. After one of the fungi, Diplodia maydis, in pure culture on maize, was added to the food of omnivorous primates there was demyelination of nerves, atrophy, degeneration and necrosis of muscle, and hepatitis.

Toxicity and moniliformin production by four recently described species of Fusarium and two uncertain taxa.

Four recently described species. Fusarium nygamai, F. dlamini, F.

Toxicity of Diplodia maydis to broilers, ducklings, and laying chicken hens.

The toxicity of corn culture material of Diplodia maydis to ducklings, chicken broilers, and laying hens was investigated. Screening trials in ducklings using a 50% dietary concentration of D. maydis culture material showed that thirteen out of sixteen isolates obtained from different corn samples from South Africa as well as ones from the US and Argentina were highly toxigenic.

T-2 toxin production by Fusarium acuminatum isolated from oats and barley.

Oats grain from South Africa was frequently found to be infested by toxic strains of Fusarium acuminatum, as was one barley sample. All 11 toxic strains tested produced T-2 toxin (0.8 to 2,600 mg/kg), and 6 of 11 strains produced diacetoxyscirpenol (0.

The isolation and identification of some toxic constituents ofAspergillus wentii wehmer.

Extraction of a maize culture of a toxinogenic strain ofA. wentii led to the isolation and characterization of three anthraquinones, three bianthrones, a xanthone and a benzophenone. The structures were derived from spectroscopic data and were supported by chemical degradation.

Toxicity of Diplodia maydis in farm and laboratory animals.

The acute toxicity of maize culture material of eight strains of Diplodia maydis in ducklings, as well as the ability of five of these strains to induce typical diplodiosis (a neuromuscular disease) in cattle and sheep was shown. Typical diplodiosis was induced in 17 sheep and 11 cattle. Two of the five toxic strains were isolated from maize involved in diploidiosis outbreaks, the others from commercial maize.

Induction of diplodiosis, a neuromycotoxicosis, in domestic ruminants with cultures of indigenous and exotic isolates of Diplodia maydis.

Diplodiosis, a neuromycotoxicosis, principally of cattle, which is characterized by ataxia, paresis and paralysis, was induced in 13 cattle, 16 sheep and 3 goats, by dosing them with Diplodia maydis [= D. zeae (Schw.) Lév.

Toxicity of rhizonin A, isolated from Rhizopus microsporus, in laboratory animals.

Maize culture material of 25 isolates of the genera Rhizopus and Mucor caused deaths in day-old unsexed Pekin ducklings when fed as a 50% (w/w) mixture with duckling feed. Nine of these isolates were tested for toxicity in young inbred male BD IX rats, which were fed a mixture of 50% (w/w) culture material and rat feed. Only one isolate of Rhizopus microsporus was clearly toxic, causing 100% mortality in rats within 10 days.

Moniliformin production and toxicity of different Fusarium species from Southern Africa.

Four new moniliformin-producing species of Fusarium were found, viz., F. acuminatum, F.

Inhibitory effect of molybdenum and vanadium salts on aflatoxin B1 synthesis by Aspergillus flavus.

The effects of the elements zinc, manganese, iron, copper, molybdenum, and vanadium, added in various salt forms, on mycelial weights and aflatoxin B1 accumulation in the mycelium of Aspergillus flavus were investigated in liquid shake cultures. Ammonium heptamolybdate, when added to a complete medium at concentrations of 50-100 mg/L, appreciably reduced aflatoxin B1 accumulation without affecting growth of the fungus. Sodium molybdate and sodium monovanadate also reduced aflatoxin B1 yields without affecting mycelial growth but to a lesser extent.

Toxic aspergilli from pistachio nuts.

Pistachio nut samples taken during various stages of development from orchards in Iran, showed that contamination with fungi occurred mainly during the later stages of nut development. Members of the genera Aspergillus and Penicillium occurred most frequently. Of the Aspergilli, the species A.

Toxicity of Diplodia maydis to laboratory animals.

Ten strains of Diplodia maydis isolated from commercial corn samples and grown on whole yellow corn at 25 degrees C for 6 weeks were toxic to ducklings and rats. The degree of toxicity depended on the incubation period and temperature. Minimum incubation periods of 3 to 4 weeks and 6 weeks were necessary to cause mortality in ducklings and rats, respectively.

New species of Aspergillus producing sterigmatocystin.

A number of species belonging to the genus Aspergillus were evaluated for their toxicity to ducklings and the ability to produce sterigmatocystin. Three new species capable of producing sterigmatocystin were found, namely, Aspergillus aurantio-brunneus, Aspergillus quadrilineatus, and Aspergillus ustus. All three were toxic to ducklings.

Production of sterigmatocystin by Aspergillus versicolor and Bipolaris sorokiniana on semisynthetic liquid and solid media.

Higher yields of sterigmatocystin were obtained with Aspergillus versicolor than with Bipolaris sorokiniana both in liquid and on solid media. The optimum temperature for sterigmatocystin production by A. versicolor was 27 to 29 degrees C and 23 degrees C for B.

Onyalai--the possible involvement of a mycotoxin produced by Phoma sorghina in the aetiology.

A number of species of fungi were isolated from millet (Pennisetum typhoides Staph and Hubb) and grain sorghum (Sorghum vulgare Pers) obtained from the households of patients suffering from onyalai. Several proved to be toxic to rats and chickens, including Phoma sorghina (Sacc.) which was the predominating fungus.

Production of sterigmatocystin.

A procedure for the isolation of pure sterigmatocystin is described. It involves cultivation of an appropriate fungus on sterile maize, and extraction and column chromatographic purification of the crude extract. With this method sterigmatocystin may be obtained at a fraction of its commercial cost.