Part 1: Rooney-Varga explains that a holistic, systems thinking approach is necessary to understand human-caused climate change. Systems thinking concepts that are critical to climate change science include the accumulation of atmospheric stocks of greenhouse gases, feedback processes that amplify or dampen the impacts of climate change, abrupt nonlinear change, and the delayed impacts of… Continue Reading
iBiology Podcasts
Alexander Rich: The Discovery of Polynucleotide Hybridization
This is the story behind the discovery of polynucleotide hybridization. In the early 1950s, the double helix structure of DNA had just been published, however, the structure of RNA was still unknown. Alexander Rich and his colleagues were investigating this question without much success until Rich combined polyadenylic acid and polyuridylic acid and, to his… Continue Reading
Peter Reddien: Molecular Mechanisms that Drive Regeneration
Many animals are able to regenerate following injury, some better than others. Dr. Reddien uses Planaria as a model system to investigate the cellular and molecular mechanisms that drive regeneration. RNAi makes it possible to inhibit specific genes in Planaria and follow the effects on protein expression and regeneration. Using this methodology, Reddien’s lab identified… Continue Reading
Jan-Michael Peters Part 2: How do Cohesin and CTCF Fold DNA in Mammalian Genomes?
In his second talk, Peters presents evidence that cohesin is indeed necessary for genomic DNA to fold into loops. Long range DNA interactions such as loops can be detected using a technique called Hi-C. Using Hi-C, Peters shows that depleting cohesin removes DNA loops, while depleting the proteins that remove cohesin from DNA, results in… Continue Reading
Jan-Michael Peters Part 1: Cohesin: Roles Beyond Sister Chromatid Cohesion?
It has been known for many years that the protein cohesin is necessary to join sister chromatids together before they are segregated during mitosis. Electron micrographs have shown that cohesin subunits form a ring complex which is thought to encircle the DNA keeping the chromatids together. When they need to separate during anaphase, the cohesin… Continue Reading
Nipam Patel Part 3: Homeotic (Hox) Genes and Evolution of Crustacean Body Plan
In his third talk, Patel explores the function of additional Hox genes in the development of crustacean body plans. Using CRISPR-Cas9 genome editing, his laboratory has characterized the expression and function of six of the nine Hox genes in Parhyale, and describes the combinatorial role of Ubx, abdA, and AbdB in the development of specialized… Continue Reading
Nipam Patel Part 2: The Role of Ubx in the Development of Crustacean Body Plan
In the second lecture, Patel describes the work of his lab to expand the studies of Hox gene function to other arthropods. Patel describes the development of specialized body parts in crustaceans, and describes the transition between feeding to locomotor appendages. Using the beach hopper, Parhyale, his laboratory, in collaboration with the laboratory of Michalis… Continue Reading
Nipam Patel Part 1: Patterning the Anterior-Posterior Axis: The Role of Homeotic (Hox) Genes
Homeotic (Hox) genes are transcription factors that dictate the development and compartmentalization (regionalization) of body parts in animals along the anterior-posterior (head to tail) axis. Using various insects and crustaceans, Dr. Nipam Patel studies how alterations in the expression of Hox genes could explain the evolution of specialized body parts in arthropods. Patel describes the… Continue Reading
Vivek Mutalik: Technical Challenges in Synthetic Biology
Dr. Vivek Mutalik highlights current challenges in synthetic biology and explains some of the solutions being implemented to address them. Mutalik discusses some of the elements that make current approaches to synthetic biology unpredictable and expensive, and reviews possible ways to move the field forward, including the development of standardized parts with predictable behaviors, robust methods… Continue Reading
Mana Parast Part 2: Modeling Placental Development
In her second seminar, Parast explains the different models to study human placental development in-vitro. Scientists can derive induced pluripotent stem cells (iPSCs) from umbilical cord cells. Parast’s laboratory first differentiates the iPSCs into trophoblasts cells which can then generate the different cells found in the placenta. Her laboratory uses these placental cells to study… Continue Reading
Mana Parast Part 1: What is the Placenta?
Dr. Mana Parast provides an introduction to placental development, the organ that every mammalian embryo needs for proper growth and development. The placenta derives from trophoblasts, embryonic cells located in the outermost layer of the embryo. Pre-eclampsia and other maternal factors can hinder placental development and therefore affect the development of the fetus. A better… Continue Reading
Stephen O’Rahilly Part 2: Why Does Obesity Lead to Adverse Health Outcomes?
What is the consequence of obesity in human health? Physically, obesity can result in lower mobility and sleeping disorders. But, in humans, the link between obesity and metabolic diseases isn’t straightforward. For example, not everyone that’s obese becomes insulin resistant. As O’Rahilly explains, the probability of an obese individual to have a metabolic disease is… Continue Reading
Stephen O’Rahilly Part 1: The Causes of Obesity: Why Isn’t everybody fat?
Easy access to nutrients has contributed to the increase in obesity in the human population. But, what is obesity and why isn’t everybody fat? Dr. Stephen O’Rahilly provides a biomedical perspective of obesity, and evaluates which genes could potentially shift the balance towards obesity. As he explains, one becomes obese when the balance between energy… Continue Reading
Maria Mota Part 3: Nutrient Sensing Modulates Malaria Parasite Virulence
The severity of malarial disease is influenced by interactions between the parasite, the host and environmental factors. In her third talk, Mota explains how her lab used a mouse model to study the impact of host nutritional status on disease severity. When they compared infections in calorically restricted (CR) mice and freely fed mice, they… Continue Reading
Maria Mota Part 2: Plasmodium Liver Stage Infection Activates Host Innate Immunity
In Part 2, Mota goes into more depth about the liver stage of malaria infection. She reminds us that when Plasmodium parasites are transferred by a mosquito bite, they first travel to the liver. Once inside of a hepatocyte, a single malaria parasite will replicate and give rise to over 10,000 new parasites that go… Continue Reading
Maria Mota Part 1: Malaria: An Overview
Malaria is currently responsible for about 500,000 deaths per year and is especially fatal to children under the age of 5 years. Two global eradication programs since 1950 have reduced the malaria burden significantly, however, progress has stalled in recent years. In her first talk, Dr. Maria Mota details the lifecycle of two malaria parasites, Plasmodium… Continue Reading
Karina Mondragon-Shem: Immunogenicity of Tick and Other Arthropod Saliva
Almost every person in the world has been bitten by a blood feeding insect or arthropod, such as a mosquito or tick. Yet, most of us haven’t thought much about arthropod saliva. The molecules found in the saliva of blood feeders play a role in disease transmission and immune recognition. Therefore, it is important to… Continue Reading
Matthew Meselson: The Semi-Conservative Replication of DNA
In 1953, Watson and Crick proposed a double-helical structure for DNA and suggested that it replicated in a semi-conservative manner. This method of replication was not universally accepted as correct, however. In this talk, Meselson recalls the events that led him to meet Frank Stahl and to plan and execute the now famous experiment proving… Continue Reading
Ruth Lehmann Part 2: Establishing Soma-Germline Dichotomy
In her second talk, Lehmann focuses on the establishment of the dichotomy between somatic and germ line fate. She explains how Drosophila germ cells develop to become so different from the somatic cells that make up the rest of the embryo. Germ cell development depends solely on maternal transcripts from the egg, while development of… Continue Reading
Ruth Lehmann Part 1: Germ Cell Development
Very early in embryogenesis, germ cells, the cells that give rise to egg and sperm, are set aside from the somatic cells which give rise to the rest of the cells in our bodies. While germ cells are not necessary for survival of the individual, they are crucial for survival of the species. In her… Continue Reading
Philipp Keller: Single-Cell Imaging: Imaging and Reconstructing Mouse Development at the Single-Cell Level
To better understand how an entire embryo develops from a single cell, Dr. Philipp Keller and colleagues developed a technique to image and quantitatively reconstruct mouse embryogenesis from gastrulation through early organogenesis at the single-cell level. Keller’s lab developed an adaptive light-sheet microscope to follow the mouse embryo for 48 hours while it’s developing its… Continue Reading
Katie Murphy: How Corn Uses Chemistry to Fight Crop Stress
Corn is the backbone of the American food supply. Yet, about 10% of corn (equal to a field as big as the entire state of Florida!) is lost to disease and other types of crop stress each year. How can we make corn and other crops hardier so that we can grow more food, using… Continue Reading
Arnold Kriegstein Part 2: Cerebral Organoids: Models of Human Brain Disease and Evolution
In his second talk, Kriegstein provides an overview of the use of cerebral organoids to study brain development and disease. Cerebral organoids are models that can be produced from induced pluripotent stem cells. Although organoids can contain the same broad categories of cell types found in the brain, organoids lack the structural, layer-like organization observed… Continue Reading
Arnold Kriegstein Part 1: The Importance of Outer Subventricular Zone Radial Glia Cells: New Concepts of Human Brain Development
How do neurons develop to confer humans their unique brain functions? Dr. Arnold Kriegstein compares and contrasts the development of neurons from radial glial cells (RGCs) in mice and humans. In mice, RGCs give rise to most of the central nervous system’s neurons and glia and provide scaffolding for neurons to migrate. In contrast, human… Continue Reading