Inactive X chromosome

Schools’ Day 2013

The programme for the 2013 Schools' Day included a quiz, a number of workshops, posters and three talks:

Talk abstracts

A battle for survival: how our immune system stays on top

Harry Hartweger - Final year PhD student in Immune Cell Biology

As human beings, we are constantly bombarded by germs which can cause infections. In order to not succumb to those threats, mammals, including humans, evolved an intricate defence system, which we now call immune system. It consists of several different types of cells serving functions such as sentinels to spot intruders or, cells to orchestrate the immune response and various types of effector cells which combat the infection. However, sometimes these immune reactions can also get out of hand and cause more destruction than the initial infection would have done.

I will outline some of the strategies and key players that our immune system employs in order to fight infections yet tries to keep the delicate balance of causing not too much collateral damage in our bodies.

Nevertheless, there is still a plethora of immunological processes that we don’t understand. For example how are these immune responses so perfectly tailored to the pathogen that they should fight? What signalling mechanisms go on inside the immune cells leading to the appropriate responses? How do we actually induce and keep memory for years and years of infections we have had before so that we can respond better and quicker? I will explain what I and the laboratory I am working in are investigating at the moment trying to understand some of those questions.

Meet the world’s most successful parasite - Toxoplasma gondii

Eva Frickel - Group leader in Parasitology

Toxoplasma gondii is a pathogen related to the malaria parasite. It is transmitted via the feces of cats (e.g. eating undercooked meat and unwashed vegetables, gardening). Intermediate hosts ‐ also humans ‐ live with the parasite for the rest of their lives. About 30% of the world population is infected with Toxoplasma, making it the world’s most successful parasite. Toxoplasma resides in the brain and can cause disease in individuals with a poorly functioning immune system, such as HIV patients. If a mother becomes infected with the parasite during pregnancy, adverse effects for the newborn include later blindness in life or mental retardation. No vaccines or drugs to fight the parasite are available. We don't exactly know how Toxoplasma maintains the intricate balance between its own survival and not killing its host. The Frickel lab studies the very early recognition of the parasite by infected host cells and the long‐term control of Toxoplasma in the infected brain.

After infection of a host cell, Toxoplasma lives in a membrane compartment, the parasitophorous vacuole (PV). Proteins called large GTPases accumulate at the PV containing less virulent parasite strains, but not more virulent strains. We believe the GTPases act as molecular switches, recruiting and controlling other defence proteins at the PV membrane. We investigate how this recruitment contributes to the parasites’s survival or elimination.

We have created mice that bear large numbers of the specific immune cells ‐ CD8 T cells ‐ that are most important in keeping Toxoplasma dormant in the brain. We use these mice to study the properties of the specific CD8 T cells and the signals that are important for these cells to be able to cross the blood‐brain barrier. We think that these studies will contribute to the design of effective countermeasures against Toxoplasma.

Genetically engineered mice and medical research

Sarah Johnson - Biological Services ‐ Procedural Service Section ‐ Manager

The use of animals in medical research is essential if we are to fully understand how the body works normally and what happens in disease. Animal research has contributed to many of the medical advances we now take for granted. We have probably all benefited from vaccines and antibiotics to prevent and treat infections, and anaesthetics used in all forms of surgery. Genetically altered animals help us go further. They can model disease for us, helping us to understand what happens when a gene is mutated or doesn't function correctly. I will be introducing why we use animals, what kind if animals and how they are used. In particular, I'll explain how we make genetically altered animals and show you some examples of how they have helped us in our understanding of disease and advancing medical research.

Workshops

Workshop 1: Chemical Biology

The chemistry stall will have a short case study and an interactive quiz on Ibuprofen. A molecular model of how this important medicine interacts with the enzyme in a cell will also be shown. In addition, there will be an opportunity to see a ‘lava lamp’ experiment.

Workshop 2: What do proteins look like?

Proteins are molecular machines which carry out all cell functions. Amino acids are linked into polypeptide chains which fold into globular shapes. X‐ray crystallography is one technique used to determine the structure of proteins at a molecular level. In this practical workshop you will get a glimpse of how this method works and what the protein lysozyme looks like!

Workshop 3: Frogs, Fruit Flies Chicks and Zebrafish

Both frogs and fruit flies are important organisms for studying developmental biology. Fluorescent proteins in the frog allow us to look at developmental processes, specifically in this exhibit at calcium flux in the heart. Using different visual markers in fruit flies we are also able to determine whether the flies contain mutations of interest. Other important model organisms include chicks and zebrafish. We are able to visualize the beating heart of a chick embryo with the naked eye, giving us information about embryonic development. Zebrafish are particularly important for their properties of organ regeneration, which may have implications for medicine in the future.

Workshop 4: The Mosquito

Mosquitoes have a complex life‐cycle. Eggs are laid in water, from which the larvae hatches and grows into a pupae from which adult mosquitos emerge. Only female adult mosquitoes bite and suck blood, to gain enough energy to lay eggs for the next generation of mosquitoes. During their bite they can transmit dangerous diseases such as malaria. We can dissect malaria‐infected female mosquitoes under a microscope to see the malaria parasite development. Parasites are found first in the gut (oocyst stage) and later in the salivary glands (sporozoite stage) thereby infecting the next person or animal it bites with malaria.

 

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