LECTURE COURSE WITH CLASS DISCUSSION ON EMBRYOS AS ORGANISMS, WITH UNFOLDING HOMEOSTATIC MECHANISMS AND CELL POLARITY AND MEMBRANE DOMAINS. EMPHASIS WILL BE ON KNOWN CAUSES OF ABNORMAL DEVELOPMENT

MEMBRANE CONTENT, PROPERTIES, FUNCTION IN DEVELOPMENT.

• HOW CAN WE STUDY THE IMPORTANCE OF CHANGES IN HOMEOSTASIS, CELL POLARITY AND MEMBRANE DOMAINS IN DEVELOPMENT?

  Original interest in setting polarity of fertilized eggs, and possible parceling out of surface to resultant cells during cleavage to result in different part of membrane mosaic going to each cell type. In later development, different receptors and pumps and channels involved in maintaining cell associations, cell volume, salt content, and excitability are found in differentiated cells.

• HOW CAN WE STUDY EFFECTS OF MUTANT GENES ON THESE PROCESSES?

• HOW TO PURIFY MEMBRANES, MEMBRANE PUMPS, ION CHANNELS, RECEPTORS,

  MEMBRANE MARKERS, LIPIDS. Problem of knowing one when one sees it.

  METHODS OF DETECTION. ATPASE IN DIFFERENT TISSUES, POLARITY, MAINTAINANCE OF CELL VOLUME AND MEMBRANE POTENTIAL.

  TYPES OF RECEPTORS.

• MECHANISMS OF CHANGE IN MEMBRANES:

  1. DEVELOPMENTAL PATTERNS EMERGE, MORPHOGENESIS: CONTROL OF GENE ACTIVITY, CELL DIVISION, INDUCTION, MORPHOGENESIS BY SIGNAL TRANSDUCTION ACROSS THE MEMBRANES
  2. PATTERN FORMATION, THE RESULT OF CELL CONTACT AND COMMUNICATION
  3. SIGNALS CAUSING CHANGING CELL MIGRATION, CELL ADHESION, SYNAPSE WITH PROPER CELLS.
  4. SIGNALS WHICH ARE NEEDED FOR PERMANENT TISSUE STRUCTURE.
  5. ABNORMAL DEVELOPMENT RESULTING FROM FAULTY SIGNALS OR SIGNAL RECEPTION.

EXAMPLE OF CLASS ACTIVITY GROUP DISCUSSION: Break up into groups of 5. Do a 5 minute freewrite about how cell macromolecules which are already present (such as adhesion molecules or enzymes or receptors) or molecules which can be newly synthesized (such as proteins or enzymes or their product lipids or carbohydrates) can effect membrane domain formation. This is just to get you thinking about it. Just write whatever comes into your mind, don't be inhibited. You will only have to share this with your group. The group will then present a collective answer to the rest of the class.

Then discuss the following with the group:

1. What kinds of genetic activity differences could make for differing kinds of polarity in different kinds of cells? Think about different unicellular organisms. Then think about multicellular organisms with many kinds of cell shapes and polarities. How could natural selection influence this?

   Kinds of lipid domains for differently charged and shaped molecules to enter.

   Cytoskeletal regulatory proteins, anchoring proteins, stabilizing mechanisms (MAPS, methylation, phosphorylation)

   Centriole position and number

   Calcium modulating proteins to regulate assembly, activation

   Cycling of material in and out of membrane

   Intracellular transport of particles or vesicles along the cytoskeleton

2. What kinds of existing patterns or activities in cells could influence other cells that are or become neighbors?
3. What makes cells have free surfaces versus adhesion sites?
4. What kinds of ionic changes could influence this. When you think about this remember nerve cells are a great example of polarized cells, and they have terrific membrane ionic fluxes during impulses, all along the cell for impulse propagation. without changing the polarity. But what kinds of things could put the channels at one end and the pumps at another? Or in the case of digestive system, the endocytosis at one side and the exocytosis at another (lipid absorption).