ETD at Indian Institute of Science
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.
Molecular Reproduction, Development and Genetics (mrdg)
Mostrando recursos 1 - 20 de 38
Stress Signaling In Development And Carcinogenesis : Role Of AMP-Activated Protein Kinase - Kumar, Hindupur Sravanth
Rapidly growing tumor cells outgrow their blood supply resulting in a microenvironment with reduced oxygen and nutrients. Using an in vitro transformation model we found that cancer cells expressing the SV40 ST antigen (+ST cells) are more resistant to glucose deprivation-induced cell death than cells lacking the SV40 ST antigen (−ST cells). Mechanistically, we found that the ST antigen mediates this effect by activating a nutrient-sensing kinase, AMP-activated protein kinase (AMPK). We further show that AMPK mediates its effects, at least in part, by inhibiting mTOR (mammalian target of rapamycin), thereby shutting down protein translation, and by inducing autophagy as...
Unravelling The Mechanisms Of Myofibrillogenesis And Human Myopathies Using Drosophila Mutants - Salvi, Sheetal S
Myofibrillogenesis is a complex process, which involves assembly of hundreds of structural proteins in a highly ordered manner to form the contractile structural unit of muscle, the sarcomere. Several myopathic conditions reported in humans are caused due to abnormal myofibrillogenesis owing to mutations in the genes coding for many of these structural proteins. These myopathies have highly variable clinical features and time of onset. Since their aetiology is poorly understood, it becomes imperative to have a model system to study the muscle defects. Present study proposes to employ the Indirect Flight Muscle (IFM) system in Drosophila melanogaster as a model...
Studies On Embryonic Stem Cells From Enhanced Green Fluorescent Protein Transgenic Mice : Induction Of Cardiomyocyte Differentiation - Singh, Gurbind
Genesis of life begins with the fusion of female and male haploid gametes through a process of fertilization leading to the formation of a diploid cell, the zygote. This undergoes successive cleavage divisions forming 2-, 4- and 8- cell embryos and their individual cells (blastomeres) are totipotent. As development proceeds, there is a gradual restriction in their totipotency, resulting in the generation of two distinct cell lineages i.e., the differentiated trophectoderm (TE) cells and the undifferentiated, inner cell mass (ICM) during blastocyst morphogenesis (Rossant and Tam 2009). During the course of development, the ICM cells can give rise to all...
Functional Analysis Of Primary Microcephaly Gene Product ASPM - Singhmar, Pooja
Autosomal recessive primary microcephaly (MCPH) is defined by congenital microcephaly and associated mental retardation with head circumference of the affected individual at least 3 standard deviations below age- and sex-means. It is a disorder of abnormal fetal brain growth which is a consequence of impaired neurogenesis. It is genetically heterogeneous with seven known loci and genes for all the seven loci have been identified: MCPH-1-MCPH1, MCPH2-WDR62, MCPH3-CDK5RAP2, MCPH4-CEP152, MCPH5-ASPM, MCPH6-CENPJ, and MCPH7-STIL. All the seven MCPH proteins localize at the centrosome. Apart from MCPH, many other proteins associated with the phenotype microcephaly have been localized to the centrosome or linked...
Cyclic AMP In Mycobacteria Adenylyl Cyclases And Cyclic AMP Receptor Proteins - Sharma, Ritu
The discovery of cyclic AMP (cAMP), nearly 50 years ago by Sutherland radically altered the appreciation of metabolic regulation. Since then the presence of cAMP and its tremendous physiological impact has been demonstrated in many prokaryotic systems. In fact, virulence mechanisms of several pathogens known today exploit cAMP dependent pathways. Interestingly the genome of Mycobacterium tuberculosis H37Rv, the causative agent of tuberculosis, encodes as many as 16 adenylyl cyclases (enzymes that convert ATP to 3’, 5’-cAMP) and 10 cyclic-nucleotide binding proteins. Recent reports show that bacterial-derived cAMP manipulates host signaling for bacterial survival, suggesting an important role for cAMP in...
Studies On Intracrine Regulators Of Ovarian Function : Examination Of Progesterone Action On Structure And Function Of Corpus Luteum In The Monkey - Suresh, P S
The control of reproductive cycles in higher primates is largely dependent on negative and positive feedback mechanisms by both steroidal and non-steroidal substances of the ovaries which regulate the function of hypothalamo-pituitary system. To gain insights into the role of INH A, the non steroidal ovarian hormone in the feedback control of pituitary FSH secretion, studies were conducted to examine the interrelationships of hormones throughout the menstrual cycle of the bonnet macaque. The findings of chapter II provide a detailed description of endocrine hormone profile during the menstrual cycle of the bonnet macaques with special attention to the feedback role...
Characterization Of Down Regulated Genes In Astrocytoma - Bhanja, Poulomi
Gliomas are the most common primary brain tumors and include astrocytomas, oligodendrogliomas and oligoastrocytomas. Astrocytomas have a high frequency of occurrence as compared to the other gliomas and several studies including ours have focused on understanding the etiology, biology and genetics of this disease. Based on the degree of malignancy, astrocytomas have been graded from I to IV. Grade I or pilocytic astrocytomas are benign tumors and have limited infiltration. On the contrary, Grade II-IV astrocytomas also referred to as diffusely infiltrating astrocytomas (DA, Grade II), anaplastic astrocytomas (AA, Grade III) and glioblastoma multiforme (GBM, Grade IV), have the tendency...
A Study Of The Roles Played By The Trishanku Gene In The Morphogenesis Of Dictyostelium Discoideum - Mujumdar, Nameeta
A hallmark feature of Dictyostelium development is the establishment and maintenance of precise cell-type proportions. In the case of D. discoideum, roughly 20% of the cells that aggregate form the stalk while the remaining 80% form the spores. In order to identify genes involved in cell-type proportioning Jaiswal et al. (2006) carried out random insertional mutagenesis (REMI) of the D. discoideum genome. This led to the identification of a novel gene, which was named trishanku (triA). A knock-out of triA did not show any defects during growth and early development but multiple defects later during development.
To understand the reasons for...
Molecular Characterization Of The SLC22A18AS Gene From The Imprinted Human Chromosome Segment 11p15.5 - Bajaj, Vineeta
The imprinting status of the SLC22A18AS gene, located in the human chromosome segment 11p15.5, was studied using PCR-SSCP analysis and fetal tissues from a battery of 17 abortuses. This gene showed monoallelic expression (genomic imprinting) in different tissues from two abortuses which were heterozygous for an SNP (c.473G>A) in its coding region. This gene was found to be paternally imprinted (maternally expressed) in five tissues namely lung, liver, brain, kidney and placenta from an abortus. The parental origin of the expressed allele could not be determined in the second abortus as both the mother and the abortus were heterozygous for...
Epigenetic Regulators Of Development In The Social Amoeba Dictyostellium Discoideum : The Roles Played By Histone Deacetylases And Heat Shock Protein 90 - Sawarkar, Ritwick
The major evolutionary transition from single-celled to multicellular life is believed to have occurred independently of the main metazoan lineages in the cellular slime moulds, of which Dictyostelium discoideum is the best-studied species. Unusually, in this case multicellular development is a facultative trait and part of an asexual life cycle. It is triggered by starvation and involves aggregation of hitherto independent and possibly unrelated free-living cells. The consequences of multicellularity in D.discoideum are strongly influenced by the environment and meaningful external perturbations are easily carried out. This makes the organism ideally suited to a study of epigenetic factors that regulate...
Characterization Of Human Mammary Stem Cells Grown As Mammospheres - Dey, Devaveena
Adult stem cells are a small population present within several tissues of an individual, possessing two unique properties: one, the ability to differentiate to give rise to all the cell types of the tissue, and second, the ability to self-renew and make more of their own kind. Owing to these two properties, stem cells underlie the process of organogenesis during development and tissue homeostasis in adult life. In the past decade a small sub-population of cells having phenotypic and functional properties similar to normal stem cells have been identified within several tumors. Only this sub-population of cancer cells seems to...
Biochemical And Functional Characterization Of Evolutionarily Conserved Metallophosphoesterases The 239FB/AB Family - Tyagi, Richa
With the advent of large scale genome sequencing efforts along with more sophisticated methods of genetic mapping, a number of loci have been identified that are associated with human diseases. Intriguingly, many genes identified in these loci remain uncharacterized. Although current annotation can provide a prediction of putative function of some of these proteins at a biochemical level, understanding their cellular roles require analysis at a single gene level.
Bioinformatic analysis carried out in the laboratory during studies on cyclic nucleotide metabolism in mycobacteria identified putative Class III cyclic nucleotide phosphodiesterases (Class III cNMP PDEs) from the non-redundant database of...