iBioseminars

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

scivee-team — Fri, 29 Jan 2010 10:24:10 -0800

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.

iBioseminars

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

scivee-team — Fri, 29 Jan 2010 10:19:09 -0800

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 event.

iBioseminars

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

scivee-team — Wed, 27 Jan 2010 10:15:11 -0800

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.

iBioseminars

Separating Duplicated Chromosomes in Preparation for Cell Division: Part 3: Moving the Chromosomes to the Spindle Poles: the Mechanisms of Anaphase A (41:27)

scivee-team — Tue, 26 Jan 2010 10:10:13 -0800

The third lecture presents evidence, largely from McIntosh's lab, that shows how microtubule depolymerization can move chromosomes in vitro and explores the nature of some of the protein complexes that can couple chromosomes to microtubules and take advantage of this reaction.

iBioseminars

Separating Duplicated Chromosomes in Preparation for Cell Division: Part 2: Understanding Mitosis through Experimentation (39:02)

scivee-team — Tue, 26 Jan 2010 10:07:17 -0800

The second lecture describes some key experiments showing the dynamics of a formed mitotic spindle and the ways these may contribute to accurate chromosome motion. Experiments that reveal aspects of the processes by which chromosomes attach to the spindle are presented. Mitotic motors are introduced and discussed in the light of what they probably do and do not accomplish to effect chromosome motion, including acting to improve the accuracy of chromosome segregation.

iBioseminars

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

scivee-team — Tue, 26 Jan 2010 10:04:32 -0800

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.

iBioseminars

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

scivee-team — Tue, 26 Jan 2010 10:01:15 -0800

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.

iBioseminars

Genes and Cells that Determine the Lifespan of C. elegans - Part 2: The Regulation of Aging by Signals from the Reproductive System, and, also, a Link Between Aging and Tumor Growth (37:16)

video_collector — Sun, 12 Apr 2009 20:53:05 -0700

Once it was thought that aging was just a random and haphazard process. Instead, the rate of aging turns out to be subject to regulation by transcription factors that respond to hormones and other signals. In the nematode C. elegans, in which many key discoveries about aging were first made, the aging process is subject to regulation by food intake, sensory perception, and signals from the reproductive system. Changing genes and cells that affect aging can lengthen lifespan by six fold, and can also delay age-related disease, such as the growth of tumors.

iBioseminars

Polyketide Biosynthesis: The Erythromycin Example - Part 3: Enzymology of Erythromycin Polyketide Biosynthesis (42:11)

video_collector — Wed, 08 Apr 2009 18:54:36 -0700

In the final part, the enzymology of the erythromycin polyketide synthase is discussed.

iBioseminars

Polyketide Biosynthesis: The Erythromycin Example - Part 2: Impact of Genetics and Molecular Biology on Understanding and Engineering Erythromycin Biosynthesis (22:44)

video_collector — Wed, 08 Apr 2009 18:53:35 -0700

In the second part, the contributions of genetics and molecular biology on investigations into erythromycin biosynthesis are summarized. The impact of these fields on biosynthetic engineering is also explained.

iBioseminars

Computational Protein Design Part 2: Designing Protein Libraries and an Example of Making a Better Fluorescent Protein (33:50)

video_collector — Fri, 03 Apr 2009 10:05:09 -0700

In this lecture, I discuss the challenges of designing new proteins that fold into a particular structure or perform a particular function. One method is to computationally design a protein based solely upon our knowledge of amino acids and protein folding, a hard task but one which has had recent successes. Another approach is to screen combinatorial libraries of proteins for a desired function.

iBioseminars

What Genomes Can Tell Us About the Past by Sydney Brenner - Part 2: (42:36)

video_collector — Fri, 03 Apr 2009 01:30:57 -0700

In the second part of talk, I explore other clues that suggest that genomes are not at equilibrium. Some genes appear to be changing more slowly and these older "fossil" genes in modern day genomes may give us insight into the distant past. I also hope to convince you that many of the great mysteries in contemporary biology do not require big research labs but can be solved through "home genomics"- piecing together information through a computer, the internet, and an inquisitive mind.

iBioseminars

The Origin of Vertebrates - Part 3: How Chordates Got Their Chord (19:09)

video_collector — Tue, 31 Mar 2009 10:50:30 -0700

In Part 3: How chordates got their chord, I discuss how the overall body plan of vertebrates, arose from the invertebrates based on knowledge of the commonalities in their developmental mechanisms. Here again, the acorn worm, offers the key comparison, being close enough to us to share some recognizable features, but far enough away to indicate the direction from whence we came.

iBioseminars

The Origin of Vertebrates - Part 2: Telling the Back from the Front or What the Chordates Invented (27:47)

video_collector — Tue, 31 Mar 2009 10:49:10 -0700

In Part 2: Telling the back from the front or what the chordates invented, I discuss why we look like invertebrate animals turned upside down, i.e. vertebrates have their central nervous system on their backs and invertebrates have it on their bellies.

iBioseminars

Role of the Neural Crest in Vertebrate Development and Evolution: Part 3: The Molecular Control of the Neural Crest Contribution to Craniofacial and Brain Development (36:10)

video_collector — Mon, 30 Mar 2009 11:57:57 -0700

Further studies have shown that the NC cells which participate in facial skeletogenesis correspond to the anteriormost region of the body axis where the genes of the Hox cluster are not expressed. If the forced expression of Hoxa2, Hoxa3 and Hoxb4 (the most anteriorly expressed Hox genes) is induced in this part of the neural fold, brain development is deeply affected with anencephaly and no skeletogenesis takes place in the face which fails to develop. This phenotype is reproduced when the anterior neural fold is surgically removed before NC emigration.

iBioseminars

Role of the Neural Crest in Vertebrate Development and Evolution - Part 2: The Role of the Neural Crest in Head Development and in Vertebrate Evolution (30:04)

video_collector — Mon, 30 Mar 2009 11:57:07 -0700

The Q/C (quail/chick) marker system revealed that apart from the peripheral nervous system (PNS), the melanocytes and some endocrine tissues, the NC plays a major role in the construction of the vertebrate head. The entire facial skeleton and part of the skull (frontal, squamosal, parietal bones) are of NC origin together with the connective tissues of the face and ventral part of the neck. The contribution of the NC to the heart and blood vessel wall (except for the endothelial cells) was also demonstrated.

iBioseminars

The Problem of Regeneration: Part 3: Molecular Basis of Regeneration: Planarians as a Model System (43:54)

video_collector — Sun, 29 Mar 2009 11:59:23 -0700

In the third and last part of this lecture, I will introduce the model system we have developed to study animal regeneration, the planarian Schmidtea mediterranea. I will review its anatomy, and the biological attributes that make these animals extraordinarily well suited to dissect the molecular and cellular basis of regeneration. I will also discuss recent work from my laboratory aimed at identifying molecules associated with regenerative capacities.

iBioseminars

The Problem of Regeneration: Part 2: Principles of Planarian Regeneration (32:49)

video_collector — Sun, 29 Mar 2009 11:58:36 -0700

In this second part of the lecture, I will briefly review the rich history of planarian research, followed by a summary of the central principles of planarian regeneration that have been derived from this extensive, often fascinating body of experimental work.

iBioseminars

Tuberculosis: A Persistent Threat to Global Health - Part 4: Targeting M. tuberculosis Carbon Metabolism In Vivo (26:12)

video_collector — Fri, 27 Mar 2009 12:14:37 -0700

All pathogens must acquire and assimilate nutrients from their hosts in order to grow and multiply -- our tissues are literally their food -- yet surprisingly little is known about this fundamental aspect of the pathogenic lifestyle. Accumulating evidence suggests that M. tuberculosis might utilize fatty acids as its principal carbon and energy source during infection. The fourth part of this lecture describes work in our laboratory that is focused on identifying the metabolic pathways that are essential for growth and persistence of M. tuberculosis in vivo.

iBioseminars

Tuberculosis: A Persistent Threat to Global Health - Part 3: Phenotypic Heterogeneity and Antibiotic Tolerance (27:15)

video_collector — Fri, 27 Mar 2009 12:00:34 -0700

The principal obstacle to successful treatment of tuberculosis is the lengthy duration of current regimens, which require administration of multiple drugs for 6-9 months. The requirement for prolonged therapy is attributed to sub-populations of bacillary "persisters" that are refractory to antimicrobials. The persisters are not drug-resistant in the conventional (heritable) sense and it is a mystery why they are spared whilst their genetically identical siblings are killed.

iBioseminars

Tuberculosis: A Persistent Threat to Global Health - Part 2: Tools for Tuberculosis Control: Not Just a Problem of Implementation (28:18)

video_collector — Fri, 27 Mar 2009 11:59:57 -0700

Tuberculosis remains one of the most important causes of human disease and death despite the introduction of vaccination in 1921 and chemotherapy in 1952. Although these interventions are inexpensive and widely available their impact is limited. The effectiveness of vaccination is unclear; in clinical trials, the protection conferred by vaccination has been variable and generally poor.

iBioseminars

The Dynamic Bacterial Cell: Part 2: Escalating Infectious Disease Threat (39:37)

video_collector — Tue, 24 Mar 2009 12:03:38 -0700

Many antibiotics, which we have taken foregranted since the 1950's, are now becoming ineffective because bacteria have developed ways of acquiring resistance. The development of new antibiotics is lagging behind the loss of the old ones in this race to combat infectious disease. Simultaneously, there is an increase in infectious diseases around the world due to over population, globalization and urbanization. This results in a lethal combination of emerging diseases and loss of effective antibiotics. Multiple factors have contributed to this escalating scenario.

iBioseminars

Technical Issues Associated with Future Large-Scale Cellulosic Biofuels Production: Part 2: Cellulosic Biofuels (48:15)

video_collector — Mon, 23 Mar 2009 16:06:23 -0700

In the second segment, the potential for various types of biofuels are compared and some of the technical challenges in production of cellulosic fuels are outlined.

iBioseminars

Host-Pathogen Interaction and Human Disease: Part 2: Helicobacter pylori and Gastric Cancer (48:57)

video_collector — Mon, 23 Mar 2009 15:08:03 -0700

Helicobacter pylori lives in the human stomach. It causes gastritis, ulcer disease and even gastric cancer. Some H. pylori can inject a protein, CagA, into gastric epithelial cells. CagA interacts with the tight junctions that bind cells together and with signaling molecules affecting motility and proliferation. CagA is associated with ulcer disease and cancer but we don't understand how it works to favor malignancy. Not long ago in history most humans carried H.

iBioseminars

Malaria presented by Joseph DeRisi Part 3: Drug Development (24:13)

video_collector — Thu, 19 Mar 2009 12:09:01 -0700

This brief set of three lectures gives a very general overview of malaria, the disease and Plasmodium falciparum, the causative agent of the most deadly form. Basic research as well as drug development efforts will also be covered in parts two and three of this series.

iBioseminars

Malaria presented by Joseph DeRisi: Part 2 Research (16:52)

video_collector — Thu, 19 Mar 2009 12:08:31 -0700

iBioseminars

Intracellular Parasitism by Trypanosoma cruzi and Leishmania": Part 3: Current Research: Strategies for Cell Invasion and Intracellular Survival (33:43)"

video_collector — Wed, 18 Mar 2009 16:10:02 -0700

In the third part of this lecture, I will discuss current work from our laboratory on mechanisms used by the intracellular parasites Trypanosoma cruzi and Leishmania to interact with mammalian cells. In addition to clarifying specific molecular strategies used by these parasites to infect and survive within host cells, these studies also led, in some instances, to unexpected insights on novel pathways regulating mammalian cell function.

iBioseminars

Intracellular Parasitism by Trypanosoma cruzi and Leishmania: Part 2: Leishmania spp and Leishmaniasis (13:36)

video_collector — Wed, 18 Mar 2009 16:00:18 -0700

In the second part of this lecture, I will present background material on Leishmania, the intracellular protozoan parasites responsible for severe human pathology in several parts of the world. I will discuss the main disease forms, the history of identification of the causative agent and form of transmission, and recent discoveries that established important concepts in our understanding of this increasingly serious infectious disease.

iBioseminars

Danger from the Wild: HIV, Can We Conquer It? Part 3: The Grand Challenge: Engineering Immunity (18:51)

video_collector — Tue, 17 Mar 2009 13:40:38 -0700

In this last segment, I describe another gene therapy strategy for HIV in which we propose to develop antibody-like proteins that can be expressed by a patient's B cells and will target the HIV virus for destruction. To achieve this objective, hematopoietic (blood) stem cells must to be targeted with the gene, which will ultimately develop into B cells that express the therapeutic molecule. The ultimate goal is to produce a life-long supply of anti-HIV neutralizing antibodies.

iBioseminars

Danger from the Wild: HIV, Can We Conquer It?": Part 2: Why Gene Therapy Might be a Reasonable Tool for Attacking HIV (30:08)"

video_collector — Tue, 17 Mar 2009 10:08:00 -0700

In part 2, I describe the growing health problem that is facing the world with the spread of HIV and the limitations of current drug therapies and vaccine strategies. We need new ideas for tackling this problem. Here and in the next segment, I describe bold strategies of using gene therapy to conquer HIV, The approach that I describe in this segment involves gene therapy to produce short hairpin RNAs (siRNA) that target the destruction of a critical co-receptor of HIV, which the viruses that needs to infect cells.

iBioseminars

Plant Viruses and Crops ": Part 2: Genetic Engineering for Virus Resistance in Plants: Different Viruses Demand Different Strategies (01:02:11) "

video_collector — Mon, 16 Mar 2009 19:13:29 -0700

The second part of the lecture will relate how this information can be used to produce crops resistant to specific viruses through different biotechnology strategies.

For further information see: http://www.ascb.org/ibioseminars/Beachy/Beachy1.cfm

iBioseminars

Apicomplexan Parasites, Pathogen Genome Informatics, and the Evolution of Eukaryotic Organelles: Part 3C: Designing and mining pathogen genome databases: From genes to drugs and vaccines (25:45)

video_collector — Fri, 13 Mar 2009 12:15:46 -0700

With the emergence of genomic-scale datasets representing all of the genes in the genome, all of the proteins in a cell or tissue, and all of the interactions and signals in an organism, biologists are increasingly faced with the challenge of how to store, integrate, and interrogate this information. How can we effectively mine large-scale datasets to expedite biological discovery, for example in the identification of new targets for anti-parasitic drug and vaccine design?

iBioseminars

Apicomplexan Parasites, Pathogen Genome Informatics, and the Evolution of Eukaryotic Organelles: Part 3B: Designing and mining pathogen genome databases: From genes to drugs and vaccines (27:10)

video_collector — Fri, 13 Mar 2009 12:15:15 -0700

iBioseminars

Apicomplexan Parasites, Pathogen Genome Informatics, and the Evolution of Eukaryotic Organelles: Part 3A: Designing and mining pathogen genome databases: From genes to drugs and vaccines (20:04)

video_collector — Fri, 13 Mar 2009 12:14:39 -0700

iBioseminars

Apicomplexan Parasites, Pathogen Genome Informatics, and the Evolution of Eukaryotic Organelles: Part 2: The apicomplexan plastid: Something old, something new, something borrowed, something green (37:11)

video_collector — Fri, 13 Mar 2009 12:14:25 -0700

Antibiotics are effective because they kill bacteria without harming humans and other eukaryotes (organisms with cells that contain nuclei). So why are the eukaryotic parasites responsible for malaria and toxoplasmosis killed by drugs like clindamycin?

iBioseminars

Stem Cells: Biology and Promise for Regenerative Medicine: Part 2: Tapping the Potential of Adult Stem Cells (1:17:03)

scivee-team — Wed, 11 Mar 2009 11:52:19 -0700

Stem cells have both the capacity to self-renew, that is, to divide and create additional stem cells, and also to differentiate along a specified molecular pathway. Embryonic stem cells are very nearly totipotent, reserving the elite privileges of choosing among most if not all of the differentiation pathways that specify the animal. In contrast, stem cells that reside within an adult organ or tissue have more restricted options, often able to select a differentiation program from only a few possible pathways, which still can make them valuable for tissue regeneration in a clinical setting.

iBioseminars

Imatinib (Gleevec) as a Paradigm of Targeted Cancer Therapies: Part 3: Extending the Imatinib Paradigm (22:09)

scivee-team — Wed, 11 Mar 2009 11:51:02 -0700

The lessons learned from the clinical trials of imatinib will be reviewed in this section. This will include examples of where imatinib has or has not worked, analysis of target expression versus activation and a discussion of how the success of imatinib can be translated to other malignancies. The section concludes with what this means for research to control or cure cancer in the coming decades.

iBioseminars

Imatinib (Gleevec) as a Paradigm of Targeted Cancer Therapies: Part 2: Imatinib Resistance and Other Diseases Targeted by Imatinib (25:12)

scivee-team — Wed, 11 Mar 2009 11:50:44 -0700

Although the majority of patients with CML respond well to imatinib, a minority of patients have relapsed. This part of the lecture will cover what has been learned about mechanisms of relapse and how this information has been translated into new therapies for patients with imatinib resistance. Although imatinib is a relatively specific inhibitor of the ABL kinase, a couple of other kinases, KIT and the platelet derived growth factor receptor are also inhibited by imatinib.

iBioseminars

Adhesion, Signaling and Cancer: Part 3: Focal Adhesions as Stress Sensors (30:57)

scivee-team — Wed, 11 Mar 2009 11:50:22 -0700

In the third segment of my seminar, I address a new frontier in cell biology, that is how cells respond to mechanical information. Cells and tissues are exposed to physical forces in vivo and excessive mechanical stress leads to a variety of pathological consequences. I describe a system for exposing cells to controlled mechanical stress and discuss the stretch response.

iBioseminars

Adhesion, Signaling and Cancer: Part 2: Discovery and Characterization of a Focal Adhesion Protein Implicated in Tumor Progression (50:54)

scivee-team — Wed, 11 Mar 2009 11:49:55 -0700

In the second segment, I describe the identification of the focal adhesion protein, zyxin, by my lab. Recent work revealed that zyxin is down-regulated upon expression of the Ewing sarcoma oncoprotein, EWS-FLI. Loss of zyxin expression results in enhanced cell motility and is also associated with failed apoptotic signaling. Evidence that zyxin shuttles between focal adhesions and the nucleus is presented. The impact of reduced zyxin expression on tumor progression is discussed.

iBioseminars

Apoptosis: Part 3: Extrinsic Pathway and Regulation of Apoptosis (23:59)

scivee-team — Wed, 11 Mar 2009 11:49:02 -0700

Apoptosis a form of programmed cell death that plays important roles during animal development, immune response, elimination of damaged cells, and maintenance of tissue homeostasis. Apoptosis is executed by intracellular proteases named caspases that are activated during the onset of apoptosis by extrinsic and intrinsic pathways. The intrinsic pathway is triggered by the release of proteins such as cytochrome c from mitochondria to cytosol and the extrinsic pathway is activated by the binding of death-inducing cytokines such as Tumor Necrosis Factor to its receptor at cell surface.

iBioseminars

Apoptosis: Part 2: Factors Involved in the Intrinsic Pathway of Apoptosis (27:39)

scivee-team — Wed, 11 Mar 2009 11:48:39 -0700

iBioseminars

Conus Peptides: Part 3: Conus Peptide Genes a "Drug Development Program" (25.36)

scivee-team — Wed, 11 Mar 2009 11:48:04 -0700

Although snails are not the first animals that come to mind when venoms are mentioned, there are in fact a large number (~10,000 species) of different venomous predatory snails. The most intensively studied of these are the cone snails (Conus), which have a large number of peptide neurotoxins present in their venoms. Some cone snail venoms are lethal to man; one species causes a 70% fatality rate.

iBioseminars

Conus Peptides: Part 2: How a Fish Hunting Snail Captures its Prey (21:31)

scivee-team — Wed, 11 Mar 2009 11:47:42 -0700

iBioseminars

The Surprising World of Prion Biology--A New Mechanism of Inheritance: Part 2: Antigen Presentation and Dendritic Cells (53:35)

scivee-team — Wed, 11 Mar 2009 11:47:22 -0700

The immune system is charged with protecting us from invading microorganisms, a task that falls to a complex array of highly specialized cell types spread throughout the body but that must work together as an integrated system. How they accomplish perform their functions can be wonderfully understood by probing the basic mechanisms governing their activities.

iBioseminars

The Surprising World of Prion Biology--A New Mechanism of Inheritance: Part II (26:08)

scivee-team — Wed, 11 Mar 2009 11:46:31 -0700

Part II: In the case of the yeast prion [PSI], the misfolding of the Sup35 protein results in a simple change in metabolism. When misfolded Sup35 is passed from mother cells to their daughters, this metabolic change is inherited. This unusual genetic mechanism changes the organism in a heritable way due to a self-perpetuating change in protein conformation with no change in its DNA.

iBioseminars

The Vertebrate Retina: Structure, Function, and Evolution: Part 3: The Evolution of Trichromatic Color Vision (43:26)

scivee-team — Wed, 11 Mar 2009 11:45:58 -0700

The third lecture describes recent work on the evolution of trichromatic color vision in humans and our primate relatives.

iBioseminars

The Vertebrate Retina: Structure, Function, and Evolution: Part 2: Human Color Vision and its Variations (44:33)

scivee-team — Wed, 11 Mar 2009 11:45:16 -0700

The second lecture focuses on the photoreceptors that mediate human color vision and the molecular basis for the common inherited anomalies of color vision.

iBioseminars

The Vertebrate Retina: Structure, Function, and Evolution: Part 1B: Photoreceptors and Image Processing (35:22)

scivee-team — Wed, 11 Mar 2009 11:44:41 -0700

In this set of lectures, Jeremy Nathans explores the molecular mechanisms within the retina that mediate the first steps in vision. The first lecture focuses on the structure of the light sensing receptors, the intracellular signals that are triggered by light absorption, and the ways in which the retina extracts information from a complex scene.

iBioseminars

Telomeres and Telomerase: Their Implications in Human Health and Disease: Part 3: Stress, Telomeres and Telomerase in Humans (45:58)

scivee-team — Wed, 11 Mar 2009 11:44:19 -0700

Telomerase, a specialized ribonucleprotein reverse transcriptase, is important for long-term eukaryotic cell proliferation and genomic stability, because it replenishes the DNA at telomeres. Thus depending on cell type telomerase partially or completely (depending on cell type) counteracts the progressive shortening of telomeres that otherwise occurs. Telomerase is highly active in many human malignancies, and a potential target for anti-cancer approaches.

iBioseminars