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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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  • ThesisItemOpen Access
    CHARACTERIZATION OF BETA-2 TOXIN PRODUCING Clostridium perfringens ISOLATED FROM ANIMALS, FOODS OF ANIMAL ORIGIN AND HUMAN
    (AAU, Khanapara, 2016) Haque, Shahnaz; Bhattacharyya, Dilip Kumar
    The present work was undertaken with a view to study the prevalence of C. perfringens in animals, birds, foods of animal origin and human. A total of 661 samples were collected from different sources, viz. animal faecal samples (433), bird faecal samples (93), human stool samples (49) and food of animal origin (86), which revealed 119 isolates of C. perfringens. The isolates were confirmed by the detection of C. perfringens alpha toxin (cpa) gene and were characterized in respect to beta 2 toxin (cpb2) gene and beta 2 toxin (CPB2). Sample wise distribution of C. perfringens was 16.17, 27.96, 32.65 and 8.14 percent in animals, birds, human stool and foods of animal origin, respectively. Irrespective of health status, isolation of C. perfringens was done from different animal and bird species. However, none of the samples collected from buffalo and horse yielded any C. perfringens isolate. All the human stool samples positive for C. perfringens were found to have a history of diarrhoea. Characterization of C. perfringens isolates in respect to the major toxin genes revealed presence of cpa (alpha), cpb (beta), etx (epsilon) and ιA (iota) toxin gene, either alone or with different combinations. Based on distribution of major toxin genes, a total of 25 isolates were identified to be of type A, one isolate as type B and 93 isolates to be of type C. Among them, type A was isolated from animal (16), birds (7) and human (2), while the only type B isolate belonged to animal. The remaining type C isolate of C. perfringens were recovered from animal (53), birds (19), human (14) and foods of animal origin (7). In addition to the major virulence genes, a total of 86 isolates of C. perfringens were found to be positive for beta2 (cpb2) toxin gene, while only 6 were found to bear the enterotoxin (cpe) gene. Out of the cpb2 positive isolates, 39 (55.71%) belonged to animals and 24 (92.31%) to birds. All the isolates of C. perfringens recovered from human and foods of animal origin were found to possess cpb2 gene. Among the cpe bearing isolates, 2 (2.86%) were of animal origin, 1 (3.85%) of birds, 2 (12.5) of human and 1 (14.29%) of foods of animal origin. Four randomly selected cpb2 positive C. perfringens isolates representing different sources were studied for their genetic diversity by PFGE, PCR-RFLP and gene sequencing. The PFGE of the cpb2 positive isolates of C. perfringens representing different sources revealed that the isolates of foods of animal origin and poultry faeces were closely related. On the other hand, the isolates of human stool and poultry faeces were found to be unrelated. Similar type of genetic diversity was observed between C. perfringens isolates of human stool and foods of animal origin. However, the human stool and animal faeces were found to be possibly related. The PCR-RFLP results revealed that isolates belonging to foods of animal origin and animal faeces were of same type. Similar restriction pattern was also exhibited by the cpb2 positive C. perfringens isolates recovered from poultry faeces and human stool. Gene sequencing results revealed that the cpb2 positive isolates of C. perfringens representing different sources were clustered into four main clusters. Cluster I contains cpb2 positive C. perfringens isolated from various sources. Similar is the case with the other two clusters. The fourth cluster contains only a faecal sample of poultry origin from NCBI. This indicates that C. perfringens have no specific host specificity and there may be interspecies transmission of the organisms. Protein profiling of the partially purified beta-2 toxin of randomly selected cpb2 positive strains of C. perfringens representing different sources was done to detect the presence of C. perfringens beta 2 toxin (CPB2) in the culture supernatant. The result revealed the presence of 28 kDa protein in all the isolates representing different sources besides the presence of various other protein bands. The presence of 43 kDa protein represents the alpha toxin and the presence of 35 kDa protein represents the beta toxin in all the isolates. Western blotting of the cpb2 positive C. perfringens isolates revealed that all the isolates were immunogenic.