molecularbioimaging-170828111112148.pptx

Biology

1. MOLECULAR BIOIMAGING

2. Introduction: Bioimaging is a recent development, that makes use of digital technology, to visualise biological processes. Example: metabolism Some examples of bioimaging as applied to the medical field include X-ray and ultrasound images, MRI, 3D and 4D body images using CT scans. There are four broad categories of bioimaging: 1.Molecular Bioimaging 2.Biomedical Imaging 3.Bioimaging in Drug discovery 4.Computational Bioimaging

3. Importance of Bioimaging: It allows in vivo imaging of biological processes, including cellular signaling and interactions and the movement of molecules through membranes. bioimaging offers precise tracking of metabolites that can be used as biomarkers for disease identification, progress and treatment response.

4. Shortfalls : There in no method in bioimaging today that quantitatively tells a clinician by how much a tumor grew or shrank in response to a drug. bioimaging cannot distinguish between benign and malignant tumors . Bioimage of tumor cells taken from (CLSM) Confocal lazer scanning microscope.

5. Some methods used in bioimaging: Green Fluorescence protein ( GFP): Derived from jelly fish Aequorea Victoria. GFP is a protein composed of 238 amino acid residues (26.9 kDa ) that exhibits bright green fluorescence when exposed to light in the blue to ultraviolet range . gfp gene has been cloned from jelly fish and has been successfully expressed in various plants .

6. 2. Fluorescence in situ hybridization ( FISH): It is a kind of cytogenetic technique which uses fluorescent probes to detect and localize the presence or absence of specific DNA sequences on chromosomes. fluorescent probes will bind to only those parts of the chromosome with a high degree of sequence complementarity.

7. Fig: protocol of FISH technique outline

8. Diagnostic Applications of FISH:

9. 3. GUS Reporter system : Derived from E.coli . Uid A gene code for 12- β- glucuronidase -enzyme enzymatic cleavage of X- Gluc ( 5-bromo-chloro-3-indolyl β -D- glucuronide ) undergoes an oxidative dimerization to yield an indigo blue precipitate . An organism is suitable for a GUS assay if it has no β- glucuronidase or if the activity is very low. Since there is no detectable GUS activity in higher plants, mosses, algae, ferns, fungi and most bacteria it perfectly suites for these organisms.

10. Rice embryo showing GUS expression. GUS gene expression on the trichomes of Arabidopsis plant.

11. 4. Fluorescence resonance energy transfer (FRET):

12. The mechanism of FRET involves a donor fluorophore in an excited electronic state, which may transfer its excitation energy to a nearby acceptor chromophore . The absorption spectrum of the acceptor must overlap fluorescence emission spectrum of the donor.