1.
Polymorphisms Of Bovine Tumor Necrosis Factor Alpha Gene And Its Association With Mastitis In Sahiwal Cows
by Huma Sattar (2013-VA-03) | Dr. Sehrish Firyal | Dr. Ali Raza Awan | Dr. Muhammad Tayyab.
Material type: ; Literary form:
not fiction
Publisher: 2015Dissertation note: Mastitis is one of the shocking maladies of milch animals causing high production losses to livestock industry of Pakistan (Kenyanjui et al. 2011). It is an inflammatory condition of udder; represent a major problem in dairy cow management. It is one of the most common and frequent disease of dairy industry. Producers suffer a huge loss due to veterinary treatment costs and necessary culling of the infected animals. It negatively affects the milk production, quality of milk, and farm economics (Fourichon et al. 2005). Increasing the disease resistance among dairy cattle is therefore desirable because without controlling mastitis, the national goals of developing dairy farming on commercial and scientific lines and production of wholesome milk which conforms to the standards of WTO Accord would remain elusive.
Mastitis is inflammation of udder that caused by physiological and metabolical changes (Schalm and Noorlander 1957). There are two main types of mastitis; clinical mastitis (characterized by classical symptoms i.e., swelling of udder, redness, clumps and clots in milk etc) and sub-clinical mastitis (not show any symptoms, Milk appear normal, udder appear normal) (Schrick et al. 2001). Mastitis is ranked as a top disease of dairy herds (Rinaldi et al. 2010). This mammary gland infection caused by pathogenic micro organisms such as Staphylococcus aureus, Streptococcus uberis, and Esherichia coli in the mammary gland (Heringstad et al. 2000).
India, China and United States are the larger producer of milk and Pakistan is on forth number in milk yield. Pakistan almost produces 36.5 million tons of milk yeild per year (Cady et al. 1983).The Sahiwal breed is well known among for its superior dairy qualities (Barker et al. 1998). Both cross and pure breed Sahiwal cows have high milk production rate (Khan et al. 2013).
It is very difficult to comprehend this disease because numerous environmental and genetic factors are involved in the origin and development of mastitis (Bradley 2002; Carvajal et al. 2013). Susceptibility and resistance to mastitis is a complex trait influenced by genetic variation of animals. Among these variations, the polymorphisms in immunity genes are principal key factors in defensive mechanism of mammary gland (Ibeagha-Awemu et al. 2008).
The mammary gland tissue is protected by immune system by two defense system; innate and acquired immunity. Innate immunity response by the host is a quick response of bacterial defense system (Mesquita et al. 2012). Innate system is a rapid and effective mechanism that activated on recognition of antigen (Akira et al. 2006). Innate immune system is activated when specific pattern recognition receptors (PRR) that are present on the surfaces which are attach to the specific pathogen (Shuster et al. 1996). PRR are presnt on leucocytes in milk and on the epithelial cells lining of udder. It is reported that T- lymphocyte subset i.e., CD4+, CD8+ and ɤδT are present in infected bovine mammary glands. (Goldammer et al. 2004; Strandberg et al. 2005).
Innate defense (nonspecific) of the mammary gland is stimulated by the physical barrier such as teat end, natural killer (NK) cells, neutrophils, macrophages and certain other soluble factors. The teat cannals are considering the main line of defense. Microorganisms enter from teat canal in milk. The main roles of teat sphincter muscles are to remain orifice close so that bacteria cannot enter. This teat canal also lined with keratin, whose estrified and non estified fatty acid function as bacteriostatics that provide protection and play role to eliminate bacteria causing mastitis (Oviedo-Boyso et al. 2007).
If a pathogen is not eliminated by the physical barrier, the acquired immune system is triggered. In comparison, this system is much faster than other immune response. The memory response is significantly stronger, long durable and more efficient to kill the pathogen. The acquired immune system (memory response) have ability to differentiate self or nonself cells and produce antibodies only against antigens through membrane bound protein called major histocompatibility complex (MHC) molecules. Specific immune system activate only when antigens bind with an MHC that is present on the surface of certain cells, this process is referred as antigen presentation. Recognition of pathogenic factors for elimination is mediated by macrophages, several lymphoid, and immunoglobulins (Ig) or antibodies (Sordillo and Streicher 2002).
The most acute responding macrophages and T-cell cytokines are TNF-α, LTF, IL1, IL6, IL8, and IFN-ɤ present in intramammary infection in cows. These genes play important role in improvement of immunity to mastitis (Burton and Erskine 2003).
Tumor necrosis factor alpha is main pro-inflammatory adipokine that is part of systematic immune defense. The main function of TNF-α gene is responsible for proliferation, differentiation and activity of many immune system cells; B lymphocytes, NK (natural killer). It also induces the production and release of many other cytokines (Wojdak Maksymiec et al. 2013) and also enhances the chemotactic and phagocytic effects of immune response. TNF-α gene contains four exons and three introns that are present on chromosome BTA23q22 (Bannerman 2009; Moyes et al. 2009).
TNF-α is a member of a group of cytokines that stimulate the specific immune system. TNF consist of 212 amino acid arranged in stable homotrimers (Kriegler et al. 1988; Tang et al. 1996). The 17-kilodalton (kDa) TNF protomers are composed of two β-pleated sheets and β-strands, joined together antiparallel (Tang et al. 1996).
TNF-α is a component of natural protection systems of humans and animals. Milk gives nourishment and disease resistance to the new born. Various cellular and soluble immune components are important for protecting the mammary gland from infectious diseases like mastitis. Mastitis affects one third of all dairy cows and cost the dairy industry about 2 million dollars annually (National Mastitis Council (1996). Dairy cattle are especially susceptible to mastitis due to diminished mammary gland defense mechanisms (Sordillo and Streicher 2002).
TNF-α is not only produced by activation of macrophages, but also other cell types such as CD4+ lymphocytes, NK cells, neutrophils, mast cells, eosinophils, and neurons. Large amounts of TNF are released in response to lipopolysaccharide, other bacterial products, and Interleukin-1 (IL-1).TNF-α stimulates the proliferation, differentiation and activity of many immune system cells; B lymphocytes, NK (natural killer). TNF-α induces the release of many other cytokines (Wojdak-Maksymiec and Mikolajczyk 2012). TNF-α also enhance the chemotactic and phagocytic effects of immune response.
. The present study is designed to determine the genetic polymorphism in exon 4 of TNF-α gene of mastitic cows and its association resistance and susceptibility towards mastitis.
Availability: Items available for loan: UVAS Library [Call number: 2224-T] (1).
2.
Genetic Identification And Molecular Classification Of Sub-Family Phasianinae Of Pakistani Bird Species Through Dna Barcoding
by Maryem Hussain (2008-VA-349) | Dr. Ali Raza Awan | Dr. Sehrish Firyal | Dr. Muhammad Tayyab.
Material type: ; Literary form:
not fiction
Publisher: 2015Dissertation note: DNA barcoding is a precise technique that uses molecular genetics tools for accurate identification, categorizing, relating and separating the phylogenies of species. Being a small sized genome and agile enough to show rapid mutation, mtDNA has been used as a pertinent marker of molecular biodiversity.The aim of this study was to develop DNA barcode for genetic characterization and classification of Sub-family Phasianinaeof Pakistani bird species. Theyhave not been genetically identified yet in Pakistan. It includes birds like domestic chicken(Gallus gallusdomesticus), aseel chicken(Gallus gallusdomesticus strain),blue peafowl(Pavo cristatus), green peafowl (Pavo muticus), white peafowl (Pavo cristatus leuticus), Kalij pheasant (Lophura leucomelanos),monal pheasant (Lophophorus impejanus),koklass pheasant(Purcrasia macrolopha), ring necked pheasant (Phasianus colchicus), Tragopan (Tragopan melanocepals) andred junglefowl (Gallus gallus). These birds are considered an important part of an ecosystembecause they play a significant role in seed dissemination, pollination of plants and disease spread which are the basic constituents of an ecosystem. They are used for food, hunting and entertainment purposes.
Mitochondrial geneCytochrome c oxidase subunit 1 (CO1)of 500bps was used as a marker for identification at specie level.Genomic DNA was extracted by each blood and tissue sample of eleven bird species (33 samples). Amplification of CO1 gene was a done by using a universal set of primers (BIRDF1 and BIRDR1)containing region of almost 750 bps (Hebert et al. 2003).Amplicons were purified and sequenced Sanger sequencing method (Sanger et al. 1977). Forward and reverse sequences were analyzed using softwaresEMBOSS merger,ClustalW, BioEdit and nBLAST. Phylogenetic analysis of selected bird species was done. Each sequence was aligned
with its reference sequences of CO1 gene present on NCBI. Every nucleotide position which did not align with the reference sequence was studied to identify SNPs. Fixation index (FST) were used to measure species diversity within a same sub population relative to that found in the entire population. Consensus sequences (500bps) generated was used to construct their phylogenetic tree to see their evolutionary relationship with other bird species. All species showed their closest linkage with their respective species. Pakistani population of peafowl and chicken species showed the close relation with same sequences generated in China. Tranopans showed its closest linkage with T. temminckii.
In conclusion, seven species ofPhasianinaesub-family of Pakistani bird species was genetically characterized first time in Pakistan by using CO1 as a barcode. It proves that DNA barcoding is an efficient and accurate molecular tool for species identifica¬tion and phylogenetic implication. This study leads to establish a DNA Data Bank that helped scientists to investigate the biodiversity, taxonomic classification, specie identification, in forensic purposes and to study the genetic and phenotypic evolution of these species. DNA barcoding through CO1 gene works as a functional tool for detectingmeat mislabeling and preventing illegitimate trade. This study has established foundations for molecular biologists to study taxonomic uncertainties at sub species level using SNP based identifying marker. It helps in preservation and identification of endangered species by generating their barcodes from even minimal evidence available.
Availability: Items available for loan: UVAS Library [Call number: 2376-T] (1).
