Protein Secretion and Vesicle Traffic : Part 3: Human Diseases of Vesicle Budding (32:28)

submitted by: scivee-team
Human COPII genes are duplicated and some may have evolved specialized functions. Two rare human diseases affect the activity of one of two copies of Sar1 and the Sec23A subunit of the COPII coat. Anderson's disease results in the failure of enterocytes of the absorptive epithelium to secrete large lipoprotein particles called chylomicrons. Point mutations in one of two copies of Sar1 results in the accumulation of chylomicrons in the ER. CLSD, a rare craniofacial disorder likely due to the...

Protein Secretion and Vesicle Traffic: Part 2: Biochemical Reconstitution of Transport Vesicle Budding (25:14)

submitted by: scivee-team
Secretion mutants that block protein exit from the endoplasmic reticulum define genes involved in the formation, targeting and fusion of a small vesicle intermediate. SEC genes corresponding to the mutants defective in vesicle budding define the cytoplasmic machinery responsible for transport vesicle morphogenesis. A biochemical reaction that reproduces ER vesicle budding was reconstituted with gently-broken yeast cells and pure recombinant Sec proteins required in vivo for this budding...

Growth Control in Animal Development: Part 2: Cell Number Control (37:13)

submitted by: scivee-team
In the second segment of my talk, I describe our work on cell number control in the rat oligodendrocyte cell lineage. Cell numbers depend on controls on both cell death and cell proliferation. We have found that oligodendrocytes are normally overproduced and kill themselves in large numbers in a competition for survival signals on the surface of the axons that the oligodendrocytes myelinate. Most differentiated cells, including oligodendrocytes, develop from dividing precursor cells that...

Membrane Rafts: Part 3: Making Rafts in Living Cell Membranes (20:39)

submitted by: scivee-team
In this lecture, I explore new ideas about how lipid components of the plasma membrane may be organized by active processes, rather than by passive mechanisms involving thermodynamic phase separation. I introduce the idea that the structure of the cell membrane at different length scales may arise as a result of the composite nature of the membrane bilayer and the underlying actin-cytoskeleton. Once again, it appears that the secret of the organization of membranes and membrane components in...

Membrane Rafts: Part 2: Looking for Functional Rafts in Cell Membranes (41:55)

submitted by: scivee-team
In this part, I focus on our laboratory's ongoing preoccupation with rafts where we study the characteristics a popular "raft-marker", a class of cell surface lipid-tethered proteins, the GPI-anchored proteins. These lipid-tethered molecules are sorted at the cell surface into a specialized endocytic pathway, suggesting their segregation at the cell surface. Here I describe collaborative interdisciplinary work from my laboratory and that of my physicist colleague, Prof. Madan Rao, where we...

Developmental Biology of a Simple Organism: Part 3: Stochasticity and Cell Fate (25:03)

submitted by: scivee-team

Part III presents research showing that B. subtilis uses a bet hedging strategy for coping with uncertainty.

Developmental Biology of a Simple Organism: Part 2: New Research on Multicellularity (18:13)

submitted by: scivee-team

Part II presents research on the capacity of B. subtilis cells to form architecturally complex communities.

Sex and Smell: Molecular Biology of Pheromone Perception: Part 3: Sex-Specificity of Pheromone Responses (30:39)

submitted by: scivee-team

Pheromones have evolved to signal the sex and the dominance status of animals and to promote social and mating rituals. In this lecture, I discuss the how pheromone sensing operates in mammals. I will discuss the molecular biology of the chemosensory receptors that are involved the first steps of pheromone sensing. At a higher level of complexity, I will discuss a distinct olfactory structure called the vomeronasal organ (VNO) and how it contributes to sex-specific behavioral responses.

Sex and Smell: Part 2: Molecular Biology of Pheromone Perception (43:43)

submitted by: scivee-team

Pheromones have evolved to signal the sex and the dominance status of animals and to promote social and mating rituals. In this lecture, I discuss the how pheromone sensing operates in mammals. I will discuss the molecular biology of the chemosensory receptors that are involved the first steps of pheromone sensing. At a higher level of complexity, I will discuss a distinct olfactory structure called the vomeronasal organ (VNO) and how it contributes to sex-specific behavioral responses.

Cell-Cell Communication in Bacteria: Part 2: Vibrio Cholerae Quorum Sensing and Developing Novel Antibiotics (19:49)

submitted by: scivee-team
Bacteria, primitive single-celled organisms, communicate with chemical languages that allow them to synchronize their behavior and thereby act as enormous multi-cellular organisms. This process is called quorum sensing and it enables bacteria to successfully infect and cause disease in plants, animals, and humans. Investigations of the molecular mechanisms underlying quorum sensing are leading to the development of novel strategies to interfere with quorum sensing. These strategies form the...