ETD at Indian Institute of Science
(529 recursos)
Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.
Mostrando recursos 1 - 20 de 34
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Amylases From A Thermophilic Fungus Thermomyces Lanuginosus Iisc 91 :Their Purification And Properties - Mishra, Ravi Shankar
A knowledge of molecular properties and structure of heat-stable enzymes is important for the understanding of basic principles governing thermo stability of proteins and evolution of life at high temperatures. Information on functional characteristics of thermo stable enzymes is necessary also for improving existing biotechnologies and developing new ones. Because of these reasons enzymes from thermophilic organisms are being exploited. In this context, amylolytic enzymes represent a useful choice for investigation from both basic and applied points of view.
a-Amylase and glucoamylase hydrolyse starch into oligosaccharides and glucose, respectively. In the present study a thermophilic fungus, Thermomyces lanuginosus, was selected as...
2.
Biodegradation Of 1-Naphthoic Acid - Phale, Prashant S
Polycyclic aromatic hydrocarbons (PAHs) are compounds containing carbon and hydrogen atoms of fused benzene rings in linear, angular or cluster arrangements. These compounds have a large (negative) resonance energy, resulting in a thermodynamically stable structures. PAHs may also contain alkyl- and nitro-substituent groups. The complexity in these molecules can be generated by substituting the aromatic carbon atom with nitrogen, oxygen or sulfur, giving rise to heterocyclic PAHs.
3.
Characterisation Of DNA Llgase And Pairing Activities From A Partially Purified Fraction From Rat Testis - Acharya, Samir
Homologous genetic recombination is a central feature of meiosis in most sexually dividing organism. It leads to the establishment of new linkage relationships between genes and is crucial for the successful completion of meiosis. It is also necessary for a variety of important cellular events like immunoglobulin rearrangement, repair of chromosome damage, gene amplification, gene expression and sister chromatid exchange.
Knowledge of the mechanisms of homologous recombination has come from extensive genetic studies on fungi. These studies have led to the formulation of various models which explain the genetic observations. Analysis of the fate of transfected DNA molecules into cells...
4.
Cloning and Expression of a Diagnostic Antigen for Invasive Amoebiasis - Shenai, Bhaskar R
A crude extract of axenically grown amoebae was used as antigen in order to develop an AB microELISA for the detection and quantitation of E. histolytica-specific IgG antibodies. This ELISA was used to screen individual sera of patients suffering from invasive amoebiasis (n=47)and control individuals(n=33). Significant titers of E-histolytica- specific IgG antibodies were present only in sera of patients suffering from invasive amoebiasis. The AB-microELISA had a sensitivity of 98% and a specificity of 97%.
Immunoblot analysis of the crude E. histolytica extract indicated the presence of several antigenic proteins. One of the common antigenic proteins recognized by the individual patients'...
5.
Cytotoxic T lymphocyte Responses Against Japanese Encephalitis Virus In Mice: Specificity And Immunotherapeutic Value - Krishna, Kaja Murali
Cytotoxic T Lymphocytes (CTL) are known to play an important role in clearing infectious virus from infected hosts in a variety of viral infections. Depending on the type of virus and mode of virus entry both class I and class II restricted CTL can contribute to protection from virus-induced disease. Although CD8 positive CTL are associated with virus elimination and control in many viral infections, elimination of neurotropic viruses from the Central Nervous system (CNS) is more complex due to the lowered expression of MHC antigens on neuronal cells. This failure to constitutively express high levels of MHC antigens by...
6.
Fatty Acid And Triacylglycerol Synthesis In Developing Seeds Of Groundnut (Arachis Hypogaea) And Pisa (Actinodaphne Hookeri) - Sreenivas, Avula
The term "lipid" covers an extremely diverse range of chemical or molecular species. Lipids, defined as molecules that are sparingly soluble in water but readily soluble in organic solvents, are broadly categorized into "neutral " or "apolar" lipids, and "amphiphilic or "polar" lipids. Neutral lipids will include simple hydrocarbons, carotenes, triacylglycerols, wax esters, sterol eaters, as wel1 as other lipids such as fatty acids, polyprenols, and sterols In which the hydrophilic function has little Impact on the overall molecular characteristics. Polar lipids include phospholipids, glycolipids, sulfolipids, some sphingolipids, oxygenated carotenoids and chlorophylls.
7.
Functions Of Nucleosomes And Other Regulatory Factor(S) In Homologous Recombination Promoted By RecA Protein - Ramdas, Jyoti
Homologous genetic recombination occurs during the life cycle of virtually every organism Genetic studies especially in prokaryotes and fungi have defined the rules of recombination, led to the characterization of alternate pathways and to the development of molecular models The biochemistry of homologous genetic recombination has advanced most productively in bacteria and fungi due to the extensive genetic understanding of these organisms The identification of mutants defective in homologous recombination, purification and characterization of the gene products that participate in recombination has brought the ultimate goal of reconstituting a cell-k free system for Eschenchia coli, at least with naked DNA...
8.
Gene Expression During Cytokinin-Induced Haustoria Formation in Cuscuta Reflexa, Roxb - Subramaniam, K
How multicellular organisms develop from a single-celled fertilized egg or zygote that in no way resembles the adult form is one of the major challenges in biology The phase of rapid cell division that follows fertilization produces individual units from which the basic body plan of the adult organism is to be constructed Elaboration of functional organs and tissues from their primordia involves
10.
Identification of Tropomyosin as the Major Cross-Reacting Crustacean Allergen - Shanti, K.N.
Seafood including crustaceans, on ingestion, are known to provoke gastrointestinal as well as systemic allergic reactions. Crustaceans are aquatic arthropods with a chitinous exoskeleton and include shrimp, lobster, prawn and crab. Earlier studies in our laboratory have led to the identification and characterization of three allergens from shrimp, designated as Sa-I, Sa-I1 and Sa-III. The former two were shown to be heat stable proteins with a mol. wt. of 8.4 and 34 kDa respectively, while Sa-III was identified as tRNA Arg and TRNATyr ). Sa-II was found to be the major allergen contributing to more than 50% of the allergenic...
11.
Invertase in a thermophilic fungus, thermomyces lanuginosus: its unusual behaviour And regulation - Chaudhuri, Amitabha
The understanding of the phenomenon of thermophily requires investigations of both thermophilic prokaryotes and eukaryotes. In the eukaryotes, thermophily is exhibited only by a few species of fungi which can grow up to 60°C. A comparative study of homologous enzymes from thermophilic and mesophilic fungi and the analysis of the observed differences is a useful approach not only in discerning the mechanisms in thermophily but also in understanding the features of fungal growth and metabolism. Because of the availability of background information of invertase from some mesophilic sources and the convenience of assaying the enzyme, it was chosen for the...
12.
Immunochemical Studies on the family of Biotin Binding Proteins - Subramanian, N
Investigations detailed in this thesis constitue a part of continuing programme of research work undertaken in this laboratory on vitamin binding proteins. Avidin from the chicken egg white, streptavidin &om the bacterium Streptromyces avidin and biotin binding proteins (BBP-I and BBP-11) from chicken egg yolk constitute a family of proteins that bind the vitamin biotin with extremely high affinities. The yolk BBPs are involved in the deposition of the vitamin in the developing oocyte in chicks whereas an antimicrobial function has been attributkl to avidin.. The fact that all these proteins bind the vitamin in the same manner, unlike biotin-dependent...
13.
Mycobacterium tuberculosis RecA intein, a novel LAGLIDADG homing endonuclease, displays dual target specificity in the presence of alternative cofactors - Guhan, N
Mobile inteins and introns are genetic elements capable of self-propagation by homing into host genes and occur in entire taxonomy: eubacteria, eukarya, archaea and viruses. The process of homing is promoted by an endonuclease encoded by the open reading frame (ORF) embedded within the genetic element. Homing endonucleases are encoded by group I and group II introns, archaeal introns, inteins, and free standing ORFs. They are believed to play a central role in rearrangement of organelle as well as nuclear genomes. Inteins are genetic elements present within protein-coding genes with dual function: protein-splicing and homing endonuclease activities. One hallmark of...
14.
Antigenic Determinants Of Chicken Riboflavin Carrier Protein: Structural And Functional Aspects - Beena, T K
Investigations detailed in this thesis constitute a part of the continuing programme of research undertaken in our laboratory on the riboflavin carrier protein (RCP) with particular reference to identification and synthesis of neutralizing antigenic determinants, design of relevant epitope mimetics with improved immunogenic characteristics and relationship between their secondary structures and immunological properties.
The riboflavin carrier protein is elaborated as a reproductive stratagem to ensure adequate vitamin deposition in the developing oocyte in the chickens. The protein is scrupulously conserved through evolution in terms of physico chemical and immunological characteristics from fish through birds to mammals, including primates. In rodents and...
15.
Oxidative Stress In The Brain: Effects Of Hydroperoxides And Nitric Oxide On Glyceraldehyde 3-Phosphate Dehydrogenase And Phosphoinositide Cycle Enzymes - Vaidyanathan, V V
In the aerobic cell, oxygen can be converted into a series of reactive metabolites, together called as "reactive oxygen species" (ROS). This large group include both radical and non-radical species such as superoxide anion (02"), hydroxyl radical ("0H), H202, nitric oxide (N0') and lipid hydroperoxides (LOOH). ROS are generated in very small amounts at all stages of aerobic life, and probably have a role in cellular regulation. However, their formation in excess leads to toxicity and damage to tissues. This situation, called 'oxidative stress', is responsible, atleast in part, to the pathophysioiogy of a number of disease states such as...
16.
Transcriptional Regulation By Nuclear Receptor Homodimers Binding To The Direct Repeat Motif DR1 : Investigations In An in vitro Transcription System Derived From Rat Liver Nuclear Extracts - Harish, S
Nuclear receptors (NRs) are important transcription factors involved in the regulation of a variety of physiological processes such as embryonic development, cell differentiation and homeostasis (for review, see Mangelsdorf et al., 1995 TenBaum and Baniahrned, 1997). In contrast to membrane bound receptors, they bind small lipophilic ligands and function in the nucleus as ligand-modulated transcription factors. The ligands for nuclear receptors include steroids (glucocorticoids, progestins, mineralocorticoids, androgens and estrogens), vitamin D3, retinoids, thyroid hormone, prostaglandins, farnesoids etc. Several other nuclear receptors are classified as orphan receptors for which no ligand has yet been identified.
More than 300 nuclear receptors have now...
17.
Studies On Cloning And Characterization Of GnRH Receptor From The Pituitary Of Bonnet Monkey (Macaca Radiata) And Functional Studies With The Antiserum To GnRH Receptor - Santra, Sumana
GnRH is a decapeptide hormone, which plays a major role in the process of mammalian reproduction. It is synthesized by the hypothalamus and binds to its cognate receptor on the pituitary, to bring about the release of gonadotropins LH and FSH. The gonadotropin releasing hormone receptor belongs to the family of G-protein coupled receptors that are characterized by the presence of seven putative transmembrane regions linked by extracellular and intracellular loops. It is a glycoprotein made up of 327 amino acids. During the last several years cloning of this receptor from a number of species has provided considerable insight into...
18.
Developmental And Functional Regulation Of DNA Topoisomerase II in Postnatal Rat Testis - Bakshi, Rahul P
Characterization of the polyoma virus chromosome as a circular, double-stranded, supercoiled DNA (Weil and Vinograd, 1963; Vinograd et al.,-1965) made it apparent that the DNA enzymatic machinery faces a formidable problem in ensuring faithful replication of genetic material. These studies initiated a search for enzymatic activities that are capable of overcoming this topological barrier and led to the discovery of DNA topoisomerase I, originally denoted as omega protein (Wang, 1971), followed by DNA gyrase (Gellert et al., 1976) from Escherichia coli. It is now established that Escherichia coli encodes four distinct topoisornerases. These include topoisomerase I (topA) (Wang, 1971), topoisomerase...
19.
Towards The Understanding Of The Structural Biology Of Histone H1 - Bharath, M M Srinivas
In the eukaryotic nucleus, an immense length of DNA is compactly packaged to generate an ordered three-dimensional hierarchical structure called chromatin (van Holde, 1988; Wolffe, A.P, 1998). This organization forms a template for various DNA transaction processes like replication, transcription, recombination etc. The different stages of organization of the chromatin finally results in the 10,000-fold compaction observed in the metaphase chromosome. The problem of how the fibres of chromatin are folded has interested biologists and biochemists for decades. It has long been recognized that the Histones play a major part in this folding. However, the distinctly different roles of the...
20.
Evaluation Of The Efficacy Of DNA Vaccines For Japanese Encephalitis In A Murine Intracerebral Japanese Encephalitis Virus Challenge Model - Ashok, M S
Japanese encephalitis virus (JEV), a member of the family flaviviridae, is one of the most important pathogens of the developing countries, causing high mortality and morbidity amongst children. The present study is aimed at the development of a DNA vaccine for Japanese Encephalitis (JE). As a first step towards developing a DNA vaccine for JE, an eukaryotic expression plasmid encoding the envelope (E) glycoprotein of Japanese Encephalitis Virus (pCMXENV) was constructed. This plasmid expresses the E protein intracellularly, when transfected into Vero cells in culture. Several independent immunization and intracerebral (i.e.) JEV challenge experiments were carried out and the results...
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