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The Nose Knows http://graphics.jsonline.

2 The Nose Knows 2

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4 THEMES IN THE STUDY OF LIFE New properties emerge at successive levels of biological hierarchy. The cell is an organism s basic unit of structure and function. (esp. two types of neurons: olfactory sensory neurons & mitral cells (a type of interneuron)) Structure and function are correlated at all levels of biological organization. (esp. the dendrites and axon of nerve cells and the cytoskeleton components that support them) Life s processes involve the expression and transmission of genetic information. Life requires the transfer and transformation of energy and matter. From ecosystems to molecules, interactions are important to biological systems. Feedback mechanisms regulate biological systems. (esp. specificity, amplification, integration, and regulation (including adaptation) in olfactory sensation & membrane potentials and the membrane proteins that create and make use of them)) Organisms interact with other organisms and the physical environment. (esp. sensory input and the olfactory cellular signal transduction pathway) Evolution biology s core theme accounts for the unity and diversity of life. SCIENTIFIC INQUIRY IN BIOLOGY In studying nature, scientists make observations and then form and test hypotheses. Science uses many technologies for specific goals of inquiry. (esp. immunofluorescent microscopy & electrophysiology) Science benefits from a cooperative approach and diverse viewpoints. 4

5 Model for cellular signal transduction pathway G-protein linked odorant receptor Volatile odorant molecule Fig

6 Model for cellular signal transduction pathway See slide 26 for details in the odorant signal transduction pathway Fig

7 Model for cellular signal transduction pathway Action potential that travels down the axon and might cross a synapse in a glomerulus Fig

8 Steps in a cellular signal transduction pathway 1. Reception 2. Transduction 3. Response Features of a cellular signal transduction pathway 1. Specificity 2. Amplification 3. Integration, including Convergence 4. Regulation, including Adaptation 8

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10 Dendrite with cilia The axon would be here Axel, Richard The molecular logic of smell. Scientific American 273(4):

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15 Microtubules are green; microfilaments are red; DNA in nucleus is blue; intermediate filaments were not stained. Fig

16 Axoneme: a part of the cytoskeleton found in cilia and eukaryotic flagella (next 2 slides) nexin Fig

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18 Axel, Richard The molecular logic of smell. Scientific American 273(4):

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This model (adapted from work at the Bourne lab) of the G protein trimer (bottom), highlights an interaction (red and yellow residues) between the beta and alpha subunits (cyan and gray,

22 This model (adapted from work at the Bourne lab) of the G protein trimer (bottom), highlights an interaction (red and yellow residues) between the beta and alpha subunits (cyan and gray, respectively) which are postulated to play an important role in mediating GPCR-triggered release of bound GDP (green, near center of alpha subunit). The gamma subunit is orange. The plasma membrane is indicated by two layers of yellow grid at the top. The integral multiple pass trans-membrane protein is the G protein-coupled odorant receptor. gamma subunit beta subunit alpha subunit 22

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24 an odorant molecule) Modified Fig Cellular responses 24

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R = 8.3145 10-3 kj/k mol T = (273.15 + 37)K = 310.15 K z = charge on ion; Na + or K + = +1 F = 96.

36 R = kj/k mol T = ( )K = K z = charge on ion; Na + or K + = +1 F = kj/mv mol [Na + ] out = 150 mm [Na + ] in = 15 mm [K + ] out = 5 mm [K + ] in = 140 mm (E X in text book) 36

37 +62 mv Na mv K + Fig

38 +62 mv Na mv K + Fig c 38

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46 Saltatory conduction down axon Fig

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48 Firestein, Stuart How the olfactory system makes sense of scents. Nature 413:

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50 Neurons expressing the P2 odorant receptor converge to a single glomerulus in the mouse olfactory bulb (sagittal whole mount), visualized by X-gal staining of neurons containing a tau-lacz fusion protein. 50

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55 Olfactory bulb section from rat with a single mitral cell filled with biocytin (red), nuclei stained with the counterstain Sytox Green (green) and olfactory receptor axons stained with olfactory marker protein (blue) 55

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57 1. Olfactory bulb; 2. Mitral cells; 3. Bone; 4. Olfactory epithelium; 5. Glomeruli; 6. Olfactory sensory neurons 57

58 Neurons expressing the P2 odorant receptor converge to a single glomerulus in the mouse olfactory bulb (sagittal whole mount), visualized by X-gal staining of neurons containing a tau-lacz fusion protein. 58

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http://cpmcnet.columbia.edu/dept/neurobeh/axel/images/image5.

60 Neurons expressing both the P2 odorant receptor and a tau-lacz fusion protein converge to the same locus in the mouse olfactory bulb. 60

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64 /press_releases/images/richard_axel_nobel_ prize1.jpg 64

65 THEMES IN THE STUDY OF LIFE New properties emerge at successive levels of biological hierarchy. The cell is an organism s basic unit of structure and function. (esp. two types of neurons: olfactory sensory neurons & mitral cells (a type of interneuron)) Structure and function are correlated at all levels of biological organization. (esp. the dendrites and axon of nerve cells and the cytoskeleton components that support them) Life s processes involve the expression and transmission of genetic information. Life requires the transfer and transformation of energy and matter. From ecosystems to molecules, interactions are important to biological systems. Feedback mechanisms regulate biological systems. (esp. specificity, amplification, integration, and regulation (including adaptation) in olfactory sensation & membrane potentials and the membrane proteins that create and make use of them)) Organisms interact with other organisms and the physical environment. (esp. sensory input and the olfactory cellular signal transduction pathway) Evolution biology s core theme accounts for the unity and diversity of life. SCIENTIFIC INQUIRY IN BIOLOGY In studying nature, scientists make observations and then form and test hypotheses. Science uses many technologies for specific goals of inquiry. (esp. immunofluorescent microscopy & electrophysiology) Science benefits from a cooperative approach and diverse viewpoints. 65

New properties emerge at successive levels of biological organization.

THEMES IN THE STUDY OF LIFE New properties emerge at successive levels of biological organization. The cell is an organism s basic unit of structure and function. (generalized animal, plant, and bacterial