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Articles 1 - 12 of 12
Full-Text Articles in Biochemistry
Invited Review: Adrenocortical Function In Avian And Non-Avian Reptiles: Insights From Dispersed Adrenocortical Cells., Rocco V. Carsia, Patrick J. Mcilroy, Henry B John-Alder
Invited Review: Adrenocortical Function In Avian And Non-Avian Reptiles: Insights From Dispersed Adrenocortical Cells., Rocco V. Carsia, Patrick J. Mcilroy, Henry B John-Alder
Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship
Herein we review our work involving dispersed adrenocortical cells from several lizard species: the Eastern Fence Lizard (Sceloporus undulatus), Yarrow's Spiny Lizard (Sceloporus jarrovii), Striped Plateau Lizard (Sceloporus virgatus) and the Yucatán Banded Gecko (Coleonyx elegans). Early work demonstrated changes in steroidogenic function of adrenocortical cells derived from adult S. undulatus associated with seasonal interactions with sex. However, new information suggests that both sexes operate within the same steroidogenic budget over season. The observed sex effect was further explored in orchiectomized and ovariectomized lizards, some supported with exogenous testosterone. Overall, a suppressive effect of testosterone was evident, especially in cells …
Inhibition Of De Novo And The Prion-Like Spread Of Amyloidogenesis Using In Vitro And In Vivo Disease Models, Johnson Anazoba Joseph
Inhibition Of De Novo And The Prion-Like Spread Of Amyloidogenesis Using In Vitro And In Vivo Disease Models, Johnson Anazoba Joseph
Electronic Theses and Dissertations
The aberrant fibrous, extracellular, and intracellular proteinaceous deposits in cells, organs and tissues are referred to as amyloids. These deposits are dominated by β-sheet structures that have been implicated in several neurodegenerative diseases and cancer. In this work, the types of amyloidosis studied include Parkinson’s disease (PD) using UA196 and NL5901 strains of Caenorhabditis elegans (C. elegans), Alzheimer’s disease (AD) using GMC101 strain of C. elegans, and cancer-associated mutant p53 aggregation in MIA PaCa-2 mutant cells. Several molecules including SK-129, NS132, NS163, bexarotene, a polyphenol (-)-epi-gallocatechine gallate (EGCG), ADH40, RD148, and RD242 were screened in vitro and in …
Investigation Of Glutamate Carboxypeptidase Ii Roles In The Folate Cycle Dependent Reproduction And Development Of Caenorhabditis Elegans, Jessica M. Derham
Investigation Of Glutamate Carboxypeptidase Ii Roles In The Folate Cycle Dependent Reproduction And Development Of Caenorhabditis Elegans, Jessica M. Derham
Masters Theses
Glutamate Carboxypeptidase II (GCPII) is a transmembrane, zinc metallopeptidase that is expressed in a wide range of organisms, including roundworms, mice, and humans. In humans, GCPII is primarily expressed in the prostate, kidneys, small intestine, and central nervous system. Within the small intestine, the expected function of GCPII is to aid in the absorption of dietary folate from the intestinal lumen. GCPII cleaves excess glutamates from folate to yield monoglutamated folate which is then readily transported into the enterocyte. Folate can then be used through the one carbon metabolic cycle for the synthesis of nucleotides, conversion of homocysteine to methionine, …
Rna Recognition By The Caenorhabditis Elegans Oocyte Maturation Determinant Oma-1, Ebru Kaymak, Sean Ryder
Rna Recognition By The Caenorhabditis Elegans Oocyte Maturation Determinant Oma-1, Ebru Kaymak, Sean Ryder
Sean P. Ryder
Maternally supplied mRNAs encode proteins that pattern early embryos in many species. In the nematode Caenorhabditis elegans, a suite of RNA-binding proteins regulates expression of maternal mRNAs during oogenesis, the oocyte to embryo transition, and early embryogenesis. To understand how these RNA-binding proteins contribute to development, it is necessary to determine how they select specific mRNA targets for regulation. OMA-1 and OMA-2 are redundant proteins required for oocyte maturation--an essential part of meiosis that prepares oocytes for fertilization. Both proteins have CCCH type tandem zinc finger RNA-binding domains. Here, we define the RNA binding specificity of OMA-1 and demonstrate that …
Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang
Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang
Victor R. Ambros
Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor. Whereas let-7 inhibits lin-41 expression in older neurons through the lin-41 3' untranslated region, lin-41 inhibits let-7 expression in younger neurons through Argonaute ALG-1. This reciprocal inhibition ensures that axon regeneration is inhibited only in older neurons. These findings show that a let-7-lin-41 regulatory circuit, which was previously …
Mutations In Conserved Residues Of The C. Elegans Microrna Argonaute Alg-1 Identify Separable Functions In Alg-1 Mirisc Loading And Target Repression, Anna Y. Zinovyeva, Samir Bouasker, Martin J. Simard, Christopher M. Hammell, Victor R. Ambros
Mutations In Conserved Residues Of The C. Elegans Microrna Argonaute Alg-1 Identify Separable Functions In Alg-1 Mirisc Loading And Target Repression, Anna Y. Zinovyeva, Samir Bouasker, Martin J. Simard, Christopher M. Hammell, Victor R. Ambros
Victor R. Ambros
microRNAs function in diverse developmental and physiological processes by regulating target gene expression at the post-transcriptional level. ALG-1 is one of two Caenorhabditis elegans Argonautes (ALG-1 and ALG-2) that together are essential for microRNA biogenesis and function. Here, we report the identification of novel antimorphic (anti) alleles of ALG-1 as suppressors of lin-28(lf) precocious developmental phenotypes. The alg-1(anti) mutations broadly impair the function of many microRNAs and cause dosage-dependent phenotypes that are more severe than the complete loss of ALG-1. ALG-1(anti) mutant proteins are competent for promoting Dicer cleavage of microRNA precursors and for associating with and stabilizing microRNAs. However, …
The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros
The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros
Victor R. Ambros
Animals developing in the wild encounter a range of environmental conditions, and so developmental mechanisms have evolved that can accommodate different environmental contingencies. Harsh environmental conditions cause Caenorhabditis elegans larvae to arrest as stress-resistant "dauer" larvae after the second larval stage (L2), thereby indefinitely postponing L3 cell fates. HBL-1 is a key transcriptional regulator of L2 vs. L3 cell fate. Through the analysis of genetic interactions between mutations of hbl-1 and of genes encoding regulators of dauer larva formation, we find that hbl-1 can also modulate the dauer formation decision in a complex manner. We propose that dynamic interactions between …
Micrornas And Developmental Timing, Victor Ambros
Micrornas And Developmental Timing, Victor Ambros
Victor R. Ambros
MicroRNAs regulate temporal transitions in gene expression associated with cell fate progression and differentiation throughout animal development. Genetic analysis of developmental timing in the nematode Caenorhabditis elegans identified two evolutionarily conserved microRNAs, lin-4/mir-125 and let-7, that regulate cell fate progression and differentiation in C. elegans cell lineages. MicroRNAs perform analogous developmental timing functions in other animals, including mammals. By regulating cell fate choices and transitions between pluripotency and differentiation, microRNAs help to orchestrate developmental events throughout the developing animal, and to play tissue homeostasis roles important for disease, including cancer.
Dauer Larva Quiescence Alters The Circuitry Of Microrna Pathways Regulating Cell Fate Progression In C. Elegans, Xantha Karp, Victor Ambros
Dauer Larva Quiescence Alters The Circuitry Of Microrna Pathways Regulating Cell Fate Progression In C. Elegans, Xantha Karp, Victor Ambros
Victor R. Ambros
In C. elegans larvae, the execution of stage-specific developmental events is controlled by heterochronic genes, which include those encoding a set of transcription factors and the microRNAs that regulate the timing of their expression. Under adverse environmental conditions, developing larvae enter a stress-resistant, quiescent stage called 'dauer'. Dauer larvae are characterized by the arrest of all progenitor cell lineages at a stage equivalent to the end of the second larval stage (L2). If dauer larvae encounter conditions favorable for resumption of reproductive growth, they recover and complete development normally, indicating that post-dauer larvae possess mechanisms to accommodate an indefinite period …
Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros
Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros
Victor R. Ambros
Animals have evolved mechanisms to ensure the robustness of developmental outcomes to changing environments. MicroRNA expression may contribute to developmental robustness because microRNAs are key post-transcriptional regulators of developmental gene expression and can affect the expression of multiple target genes. Caenorhabditis elegans provides an excellent model to study developmental responses to environmental conditions. In favorable environments, C. elegans larvae develop rapidly and continuously through four larval stages. In contrast, in unfavorable conditions, larval development may be interrupted at either of two diapause stages: The L1 diapause occurs when embryos hatch in the absence of food, and the dauer diapause occurs …
Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros
Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros
Victor R. Ambros
Why do many microRNA gene mutants display no evident phenotype? Multiply mutant worms that are selectively impaired in genetic regulatory network activities have been used to uncover previously unknown functions for numerous Caenorhabditis elegans microRNAs.
Prb/Cki Pathways At The Interface Of Cell Cycle And Development, Victor Ambros
Prb/Cki Pathways At The Interface Of Cell Cycle And Development, Victor Ambros
Victor R. Ambros
Comment on: The cyclin-dependent kinase inhibitors, cki-1 and cki-2, act in overlapping but distinct pathways to control cell-cycle quiescence during C. elegans development. Buck SH, et al. Cell Cycle 2009; 8:2613-20.