Absract Archive
July 2008
Research article
Screening and Characterization of Mycotoxin
Producing Fungi from Dried Fruits and Grains
AbstractFigs, maize, dates and grapes samples were separately analysed to identify the presence of fungi and their mycotoxins. Out of these samples, only maize and fig samples were found to contain aflatoxins. For detection of production of aflatoxins, the samples were inoculated onto AFPA media, which was again confirmed by culturing the samples on the media and observing under UV-light. Maize was found to contain aflatoxin B1, with level above 40 µg/kg, which is above the permissible amount (30 µg/kg), and aflatoxin B2 with a level of 12 µg/kg. Large figs were found to contain 12 µg/kg of aflatoxin B1. This indicates the efficacy of the aflatoxin-screening processes by UV-light and by AFPA media in identifying the food samples contaminated with mycotoxins. Four fungal species were isolated from the surface of the samples, which were subsequently cultured AFPA media for analysing the presence of mycotoxins and their quantification.
Keywords: aflatoxin, AFPA, TLC, Aspergillus flavus, Rhizopus, Mucor, PenicilliumIntroduction
Fungi are widely distributed in nature, grow over an extremely wide range of nutrients, temperature, pH, etc. and contaminate food products by many ways. Most of the fungi are toxigenic in nature, and those non-toxigenic species may impart a mouldy odour and taste during long storage. They are considered a major factor in the spoilage of foodstuffs, leading to great economic loss and a major public health hazard by producing a wide variety of mycotoxins (Dwivedi et al., 1984). Mycotoxins are the natural products yielded by fungi that evoke a toxic response when introduced in low concentration to higher vertebrates and other animals by a natural route. These diverse groups of highly toxic secondary metabolites are produced by a taxonomically wide range of food/feed borne filamentous fungi.
Authors:P. Sekar, K. Ponmurugan.
Research Article
Biodegradation of Phenol and Toluene by Bacillus sp., Pseudomonas sp.,
and Staphylococcus sp., Isolated from Pharmaceutical Industrial Effluent
Abstract
Common pollutants present in several pharmaceutical effluents are phenol and toluene. Biodegradation of phenol and toluene by Pseudomonas sp., Bacillus sp., and Staphylococcus sp., were studied. These strains were isolated from pharmaceutical industrial effluents. Phenol and toluene being a carbon source for these microbes, it is advantageous to study their bio degradation to nullify their pollutant effect. The degradation studies were carried out on varying concentrations (25 mg/L, 50 mg/L, 75 mg/L and 100 mg/L). Mixed culture showed more effluent degradation of phenol and toluene than the pure strains.
Keywords: Bio degradation, Phenol, Toluene, Minimal media, Pseudomonas, Bacillus and Staphylococcus.Introduction
Pharmaceutical effluents are wastes generated by pharmaceutical industry during the process of drugs manufacturing. Some pharmaceutical effluents contain high concentration of organic compounds such as Phenol, Toluene, Toluene, Benzene, Xylene, Nitro Benzene, Ethyl acetate, Isopropyl Ether and other aliphatic compounds. It also contains heavy metals like mercury, cadmium, isomers of hexachlorocylohexane, 1,2-dichloroethane and non-aqueous solvents. (1,2)
The increasing awareness for the protection of environment, treatment & disposal of industrial wastes has acquired great significance. Phenol and Toluene are the Common pollutants in several pharmaceutical industrial effluents. (3,4) Phenol is a toxic compound even at low concentrations and the phenolic compounds are introduced in the environment in the waste streams of several industrial operations, through its use as biocides or as byproducts of other industrial operations, such as pulp bleaching with chlorine, Water disinfections or even waste incineration.(5,6,7)
Authors :N. Prasanna,N.Saravanan, P.GeethaM.Shamnuga Prakash,P.Rajasekaran.
Research Article
Isolation and Detection of Indicator MS2 Coliphage in different environment
and sea foods by PEG Precipitation and GAC-UAPB-RT-PCR method
Abstract
The safety of drinking water is an ongoing concern in all countries. Traditionally the safety of potable water supplies has been controlled by disinfection, usually by chlorination and by coli form population estimates. However, in a recent study it was shown that coli form-free potable water may not necessarily be free of microbial pathogens. They contain various concentrations of MS2 coli phage, an indication of inadequate water treatment and a warning that human enteric viruses may also survive even after a treatment. The use of MS2 coli phage as an indicator of faecal pollution has greatly advanced the knowledge of its usefulness as an indicator of water quality. There is also sufficient evidence to suggest that the MS2 coli phage test has many advantages over traditional bacteriological and virological tests in that the procedure is economical, simple to perform, and provides results with in 8 hours. In this study the results are presented as an investigation the safety level of a variety of water like drinking water, seawater, backwater, estuary water, sewage water and sediments and seafoods. The indicator system used to test for the safety of these samples was MS2 coli phage population estimates. The above-mentioned samples were collected from different sites in Chennai city. GAC based urea Arginine Phosphate Buffer method was followed for isolation of MS2 coli phage and enteric viruses from water sample and sediment samples. The poly ethylene glycol 8000 precipitation method was applied for isolation of viruses from the seafoods. The host strain E.coli C-3000 was screened from the sewage environment by molecular biological method with specific primer. The detection of MS2 coli phage in all samples was done by double layer agar overlay plaque assay method using E.coli C-3000 as host culture. The light green plaques were obtained using IPTG and X-gal. Among the 60 samples concentrated for MS2 coli phage, the sediment and sewage water samples showed higher PFU value when compared with all other samples. Optimization of pH for the isolation of MS2 coli phage was carried out through GAC-UAPB method. Among the eight different pH ranges amended for the isolation of MS2 coli phages, the maximum isolation was observed at pH 4.0 (85.2%) When compared to other pH ranges. The MS2 coli phage acts as indicator for enteric viruses (polio, HAV and HEV). This was confirmed by MS2 the presence of coli phage positive RNA samples which were detected by RT PCR technique using specific entero virus primers. The results showed that MS2 coli phage was a good indicator of enteric viral population.
Key words: 1. Coli phage 2. enteric bacteria 3. enteric viruses
Introduction
The presence of human enteric viruses in water used for drinking, recreation, or growing shellfish in marine water may cause a risk to human health. Treatment processes and watershed management strategies designed on the basis of bacteriological criteria do not necessarily protect against virus infection because viruses are generally more persistent in the water environment and are not removed completely by treatment processes. More than 120 waterborne virus types threaten public health. These include the enterovirus group (WHO, 1979), hepatitis A virus (Deng et al., 1994), hepatitis E virus (Jothikumar et al., 1993), rotavirus (Jothikumar et al., 1994), and others. Early detection of viruses in drinking water samples will enable effective management in the public water supplies and implementation of appropriate preventive control and curative measures.
Author:D.Venkatesan.
Short Communications
Mutational effect of Penicillium chrysogenum on antibiotic Production
Abstract
β-Lactams like penicillin and cephalosporin are among the oldest known antibiotics used against bacterial infections. Industrially, penicillin is produced by the filamentous fungus Penicillium chrysogenum. The most common method used to obtain high yielding mutants by strain improvement with classical mutagenesis is by treating a population with a mutagenic agent and plating out the colonies random selected. The present study deals with testing the survival ability of Penicillium chrysogenum spores against UV irradiation and antibiotic production. (Stauffer and Backus 1954) reported the high yielding Penicillium chrysogenum Q-176, obtained by mutagenesis with UV followed by resting of random survivors and of morphological (colour) mutants. The present work describes the different morphological mutants and its antibiotic production ability at different doses of UV. Selected mutant colonies were mass cultivated by by rice flask preparation. The activity of spores from mutated colonies was studied by enhancing the spore growth in seed media for fifty four hour and fermentation media for one sixty eight hours by shake flask method. By Penicillin activity was studied by HPLC. Mutant strains of Penicillium chrysogenum treated with both chemical mutagen EMS with high sporulation and morphology variation can able to produce more amount of antibiotic penicillin.
Keywords : Antibiotic,Penicillin, Strain improvement, Mutation, Penicillium chrysogenum
Introduction
β-lactam antibiotics like penicillins and cephalosporins belong to one of the largest-selling classes of drugs worldwide with a production of forty-five thousand tons in the year 2000 [Bruggink and Roy 2001]. Penicillins and cephalosporins are produced by the filamentous fungi Penicillium chrysogenum and Acremonium chrysogenum, respectively, as well as some filamentous bacteria. These antibiotics possess as common structural motif the β-lactam ring [Brakhage 1998]. There are many species of Penicillium, and a search was started to find other species that could be tested for penicillin production(Hosler and Johnson 1953). Penicillium chrysogenum, produces approximately 200 times as much penicillin that Penicillium notatum. Scientist the began to increase the amount of penicillin produced by Penicillium chrysogenum, by irradiating it with X-Rays and UV rays in order to induce mutations of this species. This eventually lead to a mutant that produces 1000 times the amount of penicillin than Fleming’s original culture. Penicillium chrysogenum isolated from fermented and cured meat products can grow well in submerged culture.Author : M.Veerapagu.
Short Communication
Plant Growth Promoting Microorganisms (PGPMs) from Bamboo Rhizosphere
Abstract
Three bacterial and one actinomycetes isolates were isolated from the Bamboo rhizospere .All the isolates inhibited the growth of Fusarium. The isolate-1 showed maximum inhibition of Fusarium followed by isolate 3 and isolate 2. All the isolates increased the plant growth. Seed treatment of Isolate - 3 showed highest plant height but isolate 1 recorded maximum number of leaves.
Key words:PGPMs, Antagonist, Fusarium,
Introduction
The plant growth promoting microorganisms (PGPMs), are defined by three intrinsic characteristics: (i) they must be able to colonize the root, (ii) they must survive and multiply in microhabitats associated with the root surface, in competition with other microbiota, at least for the time needed to express their plant promotion/protection activities, and (iii)they must promote plant growth (Lugtenberg et al., 1999,2001; Rothballer et al., 2003; Espinosa-Urgel, 2004;Gamalero et al., 2004). The PGPR are known to participate in many important ecosystem processes, such as the biological control of plant pathogens, nutrient cycling, and/or seedling growth (Persello-Cartieaux et al., 2003; Barea et al., 2004; Zahir et al., 2004).
Pathogenic microorganisms affecting plant health are a major and chronic threat to food production and ecosystem stability worldwide. As agricultural production intensified over the past few decades, producers became more and more dependent on agrochemicals as a relatively reliable method of crop protection helping with economic stability of their operations(Compant et al.,2005). However, increasing use of chemical inputs causes several negative effects, i.e., development of pathogen resistance to the applied agents and their nontarget environmental impacts (Werger et al.,1995). Furthermore, the growing cost of pesticides, particularly in less-affluent regions of the world, and consumer demand for pesticide-free food has led to a search for substitutes for these products. There are also a number of fastidious diseases for which chemical solutions are few, ineffective, or nonexistent ( Gerhardson, 2002.). Biological control is thus being considered as an alternative or a supplemental way of reducing the use of chemicals in agriculture (Welbaum,2004 ).Baboo is a fast growing plant and can come up in water stress area.Considering these points antagonistic isolates from the bamboo rhizosphere soil was isolated and characterized for biocontrol and plant growth promotional property.Author.RaghavendraRao,B.
Short Communications
Utilization of fish (scamberomorus gattatus) waste for the isolation of Protease
Abstract
The protease enzyme was isolated and purified from the visceral organ waste of the fish Scamberomorus gattatus .The fish enzyme protease was precipitated by ammonium sulphate fractionation and purified by dialysis. The purification and molecular weight of protease was determined by SDS-PAGE. Protease activity was colorimetrically assayed using casein as a substrate and the proteolytic activity of protease determined by zymography.
Proteases or peptidases are enzymes that catalyse the breakdown of peptide bonds (proteolysis). Proteases are essential for physiological processes such as inflammation, infection, fertilization, allergic reactions, cell growth and death, blood clotting, tumour growth and bone remodeling. Industrial applications of proteases include the processing of leather and wool, food and beverage production and recently additions to cleaning products. Proteases are also therapeutically useful for various conditions and diseases. Molecules that inhibit the action of proteases are also important in research and medicine (Gupta et al., 2002).
Proteolytic enzymes from fish have received a lot of interest during the last decades. These enzymes have been found to be more catalytically active at relatively low temperatures compared to their corresponding enzymes from mammals, thermophillic organisms and plant sources. Fish enzymes have found use as digestive aids in feeds for fish larvae, cosmetics as well as in the fish industry (De Vecchi and Coppes, 1996; Gudbjarnason, 1999).Authors:T.M Mohanadevi,M.Umamaheswari, Anitha subash.
Tools & Techniques
y-H2AX assay: a technique to quantify DNA double strand breaks
Introduction:
Nucleosomes are the individual unit of hereditary material, condensed to form the chromatin filaments in eukaryotic cells. The nucleosome consists of deoxy-ribo nucleic acids (DNA) wrapped around an octamer of the four core histone proteins namely the H2A, H2B, H3, H4 and H1; of which H1 acts as linker to connect adjacent nucleosomes. The histones are highly conserved proteins involved in the packaging of DNA. Recent studies have documented evidence that histone variants are present in many mammalian cells, which have specialized biological functions in cellular metabolism (Fernandez-Capetillo et al., 2004).H2AX histone:
The histone H2A family contains three members named H2A1-H2A2, H2AZ, and H2AX. Originally, it has been reported that H2AX is an isoform of H2A and present only in lower eukaryotes. However, recent evidence showed that H2AX constitutes a major H2A species and its level varies from 2-25% of the mammalian histone H2A pool, depending upon the cell line and tissue examined. H2AX is highly conserved in eukaryotes and contains a distinguishing C-terminal extension carrying a SQ (E/D)(I/L/F/Y) consensus motif (Mannironi et al., 1989). Similar to other members of H2A family, H2AX can undergo phosphorylation, acetylation and ubiquitination to regulate the cellular events (Rogakou et al., 1998). The H2AX protein is reported to be involved in DNA repair and repair defect syndromes, regulation of cell division, cell growth and immuno-receptor rearrangement. In view of its multiple functions, it has been implicated that H2AX is an important player in cancer causing genomic instability in humans (Fernandez-Capetillo et al., 2004).Author:P. Venkatachalam