1.
Detoxification Of Aflatoxins Using Different Organic Acids
by Sana Ejaz (2013-VA-14) | Dr. Mateen Abbas | Dr. Muhammad Tayyab | Dr. Sehrish Firyal.
Material type: ; Literary form:
not fiction
Publisher: 2015Dissertation note: From global prospective of food safety and food security, mycotoxin contamination of foods has gained much attention as potential health hazards for humans and animals. Cereals and other crops are exposed to fungal attack in the field or during storage and this attack may result in mycotoxin contamination of crops. Animal feed is basic necessity for all the live stock, poultry and other animals. AF is the most important for human and animal health perspective and in developing countries such as Pakistan where climate conditions favor the formation of these toxic metabolites. Governments and private organizations of international level have established maximum residue levels (MRIs) which usually guide to control AF in feed. Therefore, the current study was planned to detoxify AF by using different organic acid treatments in animal feed collected from different dairy farms of Punjab.
The samples of cotton seed cake, maize oil cake and animal feed were collected and checked the presence of AFB1 qualitatively by TLC and quantitatively by HPLC. The samples which gave positive results were treated with different acidic treatments applied on it. Firstly checked the results of citric acid, acetic acid and lactic acid on feed sample qualitatively by TLC. TLC plates were checked under UV box and the samples which showed the detoxification of AF were quantitatively analyzed by HPLC in Toxicology Laboratory, QOL, UVAS, Lahore, Pakistan.
The average concentration of AFB1 found in the cotton seed cake, maize oil cake and mixed feed were 279.8 ppb, 34.2 ppb and 25.5 ppb, respectively much greater than permissible levels proposed by European Union. Treatments of varying concentration of citric acid, acetic acid and lactic acid were applied on positive samples (≥20 ppb) and checked their effect on rate of detoxification.
All the above mention treatments applied on the feed samples in order to obtained in vitro detoxification of AFB1. Sprayed different concentration of acetic acid, citric acid and lactic on positive samples by varying volumes and placed them over night then extracted and analyzed.
It has been observed that 1N concentration of citric acid, acetic acid and lactic acid showed complete detoxification. However, when these samples were treated with 0.5N solution of organic acids then variation was seen in rate of detoxification.
Statistically these results were analyzed by ANOVA which showed that effect of these treatments on rate of detoxification was highly significant (P<0.05). In vitro detoxification of AF by these organic acids was proved beneficial in order to reduce the animal and human health risks. However, in vivo detoxification of aflatoxin by using these organic acids should be studied in future.
Availability: Items available for loan: UVAS Library [Call number: 2283-T] (1).
2.
DNA Based Characterization Of Protease Gene From Geobacillussp.Sbs-4s
by Anam Shabbir (2012-VA-608) | Dr. Muhammad Tayyab | Ms. Huma Mujahid | Prof. Dr. Tahir Yaqub.
Material type: ; Literary form:
not fiction
Publisher: 2014Dissertation note: Proteases are hydrolytic enzymes responsible for the hydrolysis of proteins(Qadar et al.2004).These enzymes contribute major role in textile and leather industry,accounting 60% of the world wide enzyme market(Nascimento et al.2004).These enzymes are also being used in food ,pharmaceutical ,detergent, brewage sweet industry and as digestive additives in human and animal feed (Wilson, 2012).
Proteases are produced by microbes,animal and plants but microbial proteases are preferred due to ease in production and cheaper cost (Ningthoujam et al.2010).Microbes produce a variety of proteases according to their requirement that are specific in their function (Neurath 1999).Microbes might be involved in the production of intra or extracellular proteases.Extracellular proteases help the organism to absorb and utilize hydrolytic products from proteinious substrates in order to get energy by catabolism or to synthesize the biomolecules through anabolism reactions(Ningthoujamet al.2010).
Proteases can be classified in different ways.On the basis of cutting preferences these can be divided in to two groups:endopeptidases and exopeptidases (Barret and Mcdonald 1985).Exopeptidases are involved in hydrolysis of the peptide bond near N or C terminal whereas endopeptidases are responsible for the hydrolysis of peptide bond, with the chain, distant from the peptide ends(Motyan et al .2013).On the basis of catalytic residues in active site the proteases can be divided into six groups including glutamate,serine, therionine cysteine,aspartate and metalloproteases(Li et al.2013).
Microorganisms occupy all possible environments including habitats that provides appropriate conditions for growth(Sharma et al.2009).Thermophiles have ability to grow at highertemperature whereas other microbes fail to survive.There has been increasing interest in thermophilic bacteria because of their thermostable enzyme(Obeidat et al.2012).Hyperthermophiles can survive in extremely hot environment. Hyperthermophiles occupy the most basal positions of the phylogenetic tree of life(Bouzas et al. 2006). About 70 species of hyperthermophilic bacteria and archea has been isolated from different terrestrial, marine and thermal areas in the world.Hyperthermophiles are very divergent in their phylogeny and physiological properties.Proteolytic enzymes from hyperthermophiles are catalytically active at high temperature and they can alsoretain their catalytic activity in the presence of detergent and other denaturing substances (Stetter et al.1993).
Geobacillusis widely distributed thermophiles isolated from geothermal areas (Chalopagorn et al.2014).On the basis of16SrRNA gene sequences, Geobacillus belongs to Bacillus genetic group 5. It is phenotypically and phylogeneticallyconsistent group of thermophilicbacilli (Rahman et al. 2007).Bacillus and Geobacillus species are the dominant workhorses in industrial biotechnology. These bacteria produce a variety of extracellular enzymes, such as amylases, xylanases, proteases, phytases, carbonic anhydrases, catalases, pectinases. Bacillus and Geobacillus species hasability to grow at acidic, alkaline, neutral pH and at elevated temperature has positioned them among the most important industrial enzyme producers(Satyanarayana et al. 2012).
Geobacillus are gram-positive, rod-shaped, aerobic,endospore-forming obligate thermophiles.The growth temperature for various Geobacillus species ranges from 37 to 75 °C and pH range of 6.0 to 8.5.The members of Geobacillusare homologus to each other and share homology 99% among them(Tayyab et al.2011). The genus Geobacillusthermophilicstrains, produce a variety of thermostable hydrolytic extracellular enzymes, such as proteases, amylases, and lipases used in various industrial applications (Wiegand et al. 2013)
GeobacillusSBS-4S was isolated from a hot spring located in Gilgit, Northern areas of Pakistan.Geobacillus SBS-4S strain is Gram positive, rod-shaped bacteria and occurs in chains. That could grow at a wide range of temperature (45 to 75˚C) and pH ranging 5.5 to 9.5.Geobacillus SBS-4S produced several extracellular enzymes including amylase, protease and lipase.The comparison of the strain SBS-4S with the already reported species of genus Geobacillus showed that SBS-4S is resistant to antibiotics such as streptomycine, spectinomycin and rifampicin(Tayyab et al.2011).
Availability: Items available for loan: UVAS Library [Call number: 2242-T] (1).
