Geeta Sumbali

Keratinolysis by poultry farm soil fungi

Species of Chrysosporium, Malbranchea, Scopulariopsis, Microascus, and Gliocladium isolated from poultry farm soils were grown on two keratin media. All the test fungi could grow on keratin (human hair) and degrade it, releasing sulphydryl-containing compounds detected as extracellular keratinase, cysteine and total proteins. Glucose supplemented keratin medium supported maximum keratinolysis. Keratinase activity also changed the pH of the medium towards alkalinity and species with strong keratinolytic ability were noted to render the culture medium more alkaline than those that were less keratinolytic.

Production of extracellular keratinases by keratinophilic fungal species inhabiting feathers of living poultry birds (Gallus domesticus): A comparison

Fourteen species of keratinophilic fungi belonging to ten genera (Chrysoporium, Malbranchea, Chaetomium,Sepedonium, Microascus, Scopulariopsis, Curvularia, Fusarium, Aspergillus, Penicillium) were isolated from feathers of about one hundred living poultry birds. The isolated fungi were compared for their keratinase activity after growing them on two different media: (1) basal salts solution containing natural keratin (human hair) as the only source of carbon and nitrogen; (2) the medium was supplemented with a minor amount of readily assimilable source of carbon along with natural keratin. All the test fungi could grow on keratinous material, degrading it and releasing sulphydryl containing compounds detected as cysteine, total proteins and extracellular keratinase. Maximum enzyme release by these fungi occurred in the broth supplemented with glucose and vitamins, thereby indicating a correlation between the mycelial biomass and production of proteolytic keratinases.

Impact of some ecological factors on the occurrence of poultry soil-inhabiting keratinophiles.

Investigations were conducted to assess the ecological factors governing distribution and survival of keratinophilic fungi in poultry farm soils. All the poultry farm soils were rich in humus and the keratinophilic fungi were generally found to be proportional to the soil organic matter. These soils were nearly neutral to weakly alkaline and organically rich with a high content of organic carbon, nitrogen, phosphorus, potassium, magnesium, calcium and iron.

Co-occurrence of aflatoxin B1 and cyclopiazonic acid in sour lime (Citrus aurantifolia Swingle) during post-harvest pathogenesis by Aspergillus flavus

During hot and humid seasons, extensive rot of sour lime was observed to be caused by Aspergillus flavus. In view of this, investigations were undertaken to obtain data on the production of various toxins by A. flavus during post harvest pathogenesis of sour lime. Sixty percent of the pathogenic A. flavus isolates were detected to be aflatoxin B1 producers in sour lime tissue. It was also noted that thirty three percent of aflatoxigenic A. flavus isolates had the potential to coproduce cyclopiazonic acid (CPA). Such aflatoxigenic isolates produced quantitatively more CPA (ranging from 250.0 to 2501.3 μg/kg) than aflatoxin B1 (ranging from 141.3 to 811.7 μg/kg) in the affected sour lime. This study demonstrates for the first time that sour lime are a favourable substrate for aflatoxin B1 and cyclopiazonic acid production by A. flavus isolates. This is of great concern to the health of consumers.

Incidence of aflatoxin producing strains and aflatoxin contamination in dry fruit slices of quinces (Cydonia oblonga Mill.) from the Indian State of Jammu and Kashmir

An investigation was undertaken to obtain data on the occurrence of aflatoxins and the aflatoxin producing potential of Aspergillus flavus strains isolated from dry fruit slices of quinces produced in jammu and Kashmir, India. A total of 147 A. flavus isolates recovered from dr fruit slices were grown in liquid rice flour medium and screened for the production of various aflatoxins by thin layer chromatography. The results showed that 23.14% of the tested isolates were aflatoxigenic, producing aflatoxins B1and B2 in varying amounts. Aflatoxins G1 and G2 were not detected. All 25 of the investigated market samples were also found to be aflatoxin B1 positive and the level of contamination ranged from 96 to 8164 μg/kg of the dry fruit which is quite high in comparison to the permissible level of 30 ppb. As per these results biochemical composition of dry fruit slices of quinces, along with climatic conditions seem to be very favourable for aflatoxin production by the toxigenic A. flavus strains. Therefore,monitoring of aflatoxins in dry fruit slices of quincesis recommended for this region.

Keratinophilic fungi from poultry farm soils of Jammu, India

Soil samples from ten poultry farms of Jammu, Northern India, were screened for the presence of keratinophilic fungi by the keratin-bait technique. 20 species belonging to nine genera ( Chrysosporium, Malbranchea, Scopulariopsis, Microascus, Gliocladium, Circinella, Fusarium, Aspergillus and Penicillium ) were isolated. Some of them are known to be potential pathogens.

Keratinophilic fungi from feathers of Indian poultry birds

Feathers were collected directly from living poultry birds and studied for the prevalence of keratinophilic fungi on them. All the samples investigated were found to be positive and fourteen species of keratinophilic fungi in ten genera were isolated. Of these Malbranchea chrysosporoidea is a new addition to the Indian mycoflora.

Association of Patulin With Market Samples of Dry Fruit Slices of Quinces (Cydonia Oblonga Mill.) from Jammu and Kashmir, India

Patulin, also known as expansin, penicidin, leucopin, tercinin, clavacin, claviformin and clavatin, is a mycotoxin that was first isolated by Chain et al. (1942) and was originally investigated because of its potential as an antibiotic. All the mycotoxins are, in general, important environmental pollutants synthesised by moulds as secondary metabolites possessing low molecular weight, non-antigenic properties and capable of eliciting a toxic response in man and animals. It is known that most of the antibiotics are in practice mycotoxins, the difference being one of degree rather than of kind. Although patulin does possess some desirable antimicrobial properties, it has also been found to be toxic to a wide range of other biological systems (rats, cats, mice and rabbits), on account of which its use as an antibiotic was abandoned (Stott and Bullerman, 1975).

Detection of some new Trichosporon species from the dystrophied nails of three female members of a family from North Indian State of Jammu and Kashmir

Dermatophytes are considered as the main pathogens responsible for onychomycosis, but recently successive isolations of yeast‐like fungi from the infected nails has led to consider these also as primary agents of nail infections. Trichosporon species which are non‐candidal, basidiomycetous, yeast‐like, anamorphic fungi are commonly isolated from soil but they are also emerging as important etiological agents of onychomycosis. Three species of Trichosporon viz., T. asahii, T. asteroides and T. faecale were isolated from the infected nails of three female members of a family from district Doda of Jammu and Kashmir State. Among the isolated species of Trichosporon, T. asahii was recovered from the nail samples of all the three members, thus confirming its recognition as a main pathogenic species of onychomycosis. So far, there is no report of T. asteroides and T. faecale causing onychomycosis and hence they constitute new additions to the list of onychomycotic fungi. Some of the predisposing factors like low socio‐economic condition, poor hygiene, frequent exposure of finger nails to water and dirt, climatic conditions and nail trauma were observed to be the main causes of nail infection in these patients. However, a link between the pathogenic genus and the genetic makeup of the patients is also probable.

Camouflaged Mycotoxins in Some Field Crops and Forages: A Review

Mycotoxins are secondary mould metabolites, which are associated with toxic effects in living forms including humans, birds and animals and are chiefly produced by some species of Aspergillus, Penicillium and Fusarium. They are produced in cereal grains and forages quite before or during or after harvesting under diverse environmental conditions. Owing to their diverse toxic effects and synergetic properties, mycotoxins are considered risky for the health of consumers ingesting foods contaminated with them. Majority of the reported mycotoxins are worldwide in distribution and impose severe health risks to all the living forms. The phytopathogenic Fusarium species, which are the causal agents of ‘head blight’ (scab) of small grain cereals and ‘ear rot’ of maize, occur worldwide and may accumulate several mycotoxins in the infected kernels, some of which show remarkable impact on the health of consumers. While F. graminearum, F. culmorum, F. poae, F. avenaceum and Microdochium nivale predominantly cause diseases of small grain cereals, maize is predominantly attacked by F. graminearum, F. moniliforme, F. proliferatum and F. subglutinans. Since fungal infection and subsequent mycotoxin production begins in the field prior to harvest, the focus of this review encompasses occurrence and management of various crops diseases (wheat, barley, rice, maize and sorghum) caused by toxigenic fungi and that of forage crops harbouring toxigenic endophytic fungi. The review also focuses on the influence of various factors on disease development and production of camouflaged mycotoxins in the field.