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Lecture on Environments (at Parsons, March 4, 2011)

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  • What makes someone male/female is determined by the hormonal milieu in the embryo. Default is female embryo (in birds it is male). And then the XY genes in the gonadal ridge start hormonal synthesis  making the embryo male. Female embryos have a Mullerian Inhibitory Substance
  • So what do you think about such probable “pre conditioning”?
  • Prenatal stress can be alleviated by music, calm environments… The prenatal environment is entirely submerged in water. How has technology altered the “disturbance” of the pre-natal environment? How has it improved it? Advantages of ultrasound and amnio. Disadvantages? Is there something like too much ultrasound?
  • How prenatal stress may affect us as adults. GC- glucocorticoids (cortisone receptors). Limbic system – emotional centers. HPA – pituitary/adrenal axis. So prenatal stress can determine how you respoond emotionally, as well as physiologically
  • How you are treated as a baby affects adult responses. Most experiments in sheep. Testingboth maternal and progeny responses. Anxiety, maternal separation etc. increase cortisol levels. May affect memory, emotional responses as adults
  • Day-night – we have diurnal cycles. All our hormones have such cycles. Nothing is a steady flat line.
  • How photoperiod affects reproduction. Hypothesis: When we place fish that reproduce normally under short day (winter day length)) conditions they will respond by a stop in reproduction . On re-introducing long days (summer day length, they will start breeding again.We will also see how brain responds. GnRH neurons: neurons in brain that control reproduction and associated behavior in most animals studied.
  • Brain chemistry as well as fertilty affected. Moving from long to short days  stop in breeding (see drop in eggs). Slowing down of brain response. Also gonad size shrunk. Moving back to long day  back to regular levels of embryos. Increase in brain physiology. Gonads moved back to regular weight.
  • Circadian rhythms as a result of chnages in photoperio. Hibernation in guinea pigs. Also in winter gonads shrink.
  • Call center. Fertility and depression problems as diurnal cycle is affected (more anecdotal and obsrevational. Studies should be done). In the Netherlands there is free psychological helpoffered to workers who do not get enough sunlight during work hours.
  • What is the extension of your environment?
  • Your DNA may be predisposed to certain environmental inputs such as Fat. Methylation and Histone wrapping change the DNA pre-disposition, allowing for environmental manipulation
  • Why are identical twins not so identical; movie on website. See allied movies too.
  • Alters local environment in brain/body/embryo.. Thereby altering what that area becomes
  • Brain regions are formed based on gradients… chemical environments on a microscale. Panel +/+ means Emx2 present. -/-means it is absent. Notice that the brain regions alter in area and shape when emx2 is absent. Cad 6 and 8 are proteins that codify specific brain regions
  • Such chemical gradients can determine if you have an eye or not…
  • Making a proper brain. So determining brain regions is a mixture of gradients of different chemicals. If we alter with this chemical environment, you get an abnormal brain.
  • We can now delve into the environments/see them on a nano-scale; nanobots still an idea, but can soon become reality. - nanomandala
  • Making materials that can help us use natural examples better. We are now able to see nano-environments of natural materials, that help us understand their physical properties better. Why a lotus leaf can be hydrophobic. Why shark skin offers least resistance to water. Etc.
  • Indian mythology – krishna’s mother looks into his mouth to see the whole cosmos. The more deeper we look, our world is now becoming bigger and bigger.
  • Blue fish (dominant – territorial, get mates, get resources, bullies). White – non territorial. When you take them and place them in a tank, with no territorial males  they transform. Become bigger, become blue, get eye stripe. Brain chemistry changes, behavior is altered. Look at transformation on left.
  • Showing changes in brain chemistry, T6 (BLUE, left) moved from being big and dominant to becoming non-territorial/submissive.T1 and T4 moved from being non-territorial, to territorial (RED, right)
  • Environment

    1. 1. Environment Siddharth Ramakrishnan
    2. 2. What is environment? <ul><li>a : the complex of physical, chemical, and biotic factors (as climate, soil, and living things) that act upon an organism or an ecological community and ultimately determine its form and survival b : the aggregate of social and cultural conditions that influence the life of an individual or community </li></ul>
    3. 3. What do you think of when we use the word environment?
    4. 4. What environment? <ul><li>You are what you eat </li></ul><ul><li>You are where you live </li></ul><ul><li>You are where you developed </li></ul>
    5. 5. In Utero
    6. 6. Development
    7. 7. Effects of Prenatal Stress <ul><li>The number of stress receptors in the brain and their activation profiles may be determined in the embryo </li></ul><ul><li>So how you respond as an adult to stress may be determined quite early on </li></ul>
    8. 9. Effect of Prenatal Stress
    9. 10. Neonatal Environment
    10. 11. Effects of Neonatal stress/nutrition
    11. 12. What about light, day, night, cycles?
    12. 13. Experimental Design <ul><li>Collect embryos daily </li></ul><ul><li>N =12 pairs at start </li></ul><ul><li>Served as LD controls throughout experiment </li></ul>LD Control LD  SD SD  LD <ul><li>Collect embryos daily </li></ul><ul><li>When egg laying stopped, N =6 males sacrificed </li></ul><ul><li>GSI determined </li></ul><ul><li>TN-GnRH neuron electrophysiology recorded </li></ul><ul><li>Collect embryos daily </li></ul><ul><li>When egg laying reached control levels, N =6 males sacrificed </li></ul><ul><li>GSI determined </li></ul><ul><li>TN-GnRH neuron electrophysiology recorded </li></ul>0h 0800h 1800h 2400h 0h 0800h 2400h 0h 0800h 2400h 16L:8D 12 days 33 days 20 days
    13. 15. Circadian rhythms and hormones
    14. 17. Urban vs. Rural vs. Virtual
    15. 19. Micro and nanoenvironments
    16. 20. Epigenetics
    17. 21. Epigenetics
    18. 22. Effect of Hox genes <ul><li>Transcription factors </li></ul>
    19. 25. Developing brain regions
    20. 27. <ul><li>Low drag materials </li></ul><ul><li>Compound lenses </li></ul><ul><li>What about cotton candy? </li></ul>
    21. 28. The Inside is larger than the Outside
    22. 29. Social <ul><li>Social environment is very important </li></ul><ul><ul><li>Fish that change sex when other fish act like it is male/female; queen bee; naked mole rat roles; monogamy </li></ul></ul><ul><li>How does social environment shape us? </li></ul><ul><li>How is this different now? </li></ul><ul><li>How do social networking sites alter society? </li></ul><ul><li>Twitter campaign in the middle east </li></ul><ul><li>Elections? Democracy? </li></ul><ul><li>What about friendship – has the word been redefined? </li></ul><ul><li>What is privacy? </li></ul>
    23. 30. Social regulation of GnRH <ul><li>Cichlid fish ( Haplochromis burtoni ) </li></ul><ul><li>Social factors  growth and reproduction </li></ul>
    24. 32. How our environment affects us <ul><li>Development </li></ul><ul><li>Adaptation </li></ul><ul><li>Habituation/Facilitation </li></ul><ul><li>Social Responses </li></ul><ul><li>Evolution </li></ul>
    25. 33. So what we do to our environment, is in turn altering us , subtly, slowly but definitely