Hello my friends, Here comes the first study blog from me regarding Screening. Let us go with the introduction first. Screening in general means "Separation". Why do we perform screening? Well, the answer is simple. For a teacher, who wishes to select a class leader "screens" an entire class of 60 students to get the desired product viz. an eligible leader. This candidate is the study of interest. Similarly the nature is full of microbes. What is the case, if we want to choose only bacteria, or only virus or only actinomycetes??. Take an example of soil sample. Can you tell what exact type of microorganisms it contains?? Yes. It is very difficult. Hence forth screening techniques are developed. Screening is defined as "Use of highly selective procedures to allow the detection and isolation of only those microorganisms of interest from among a huge population." This procedure is carried out by discarding undesired microbes and selectively choosing microbes of our interest.[2] Some of the most intelligent screening methods which we use today are the findings of Japanese scientists particularly by Omura and group. Screening procedures are also employed in Pharmaceutical Biotechnology research programs.[3] The latest development in screening is "high throughput screening". What is high throughput screening? It is a screening procedure in drug discovery gene/protein function determination or metabolite/biological activity where in huge samples (thousands) are tested daily against a particular standard. This modern technique uses applications of robotics, complex software, advanced micro liquid handling, highly sensitive detection methods. This screening is the initial step in drug discovery.[1] Applications in Industry. HTS technology is widely used now a days in R&D centres. Usually through this technique 10,000 - 30,000 samples are being tested daily. From these huge samples only 2 or 3 may be showing industrially promising results . Another technology is Ultra High Throughput Screening where 1,00,000 samples are tested.[1] This technique is also used in safety studies, screening of compounds with unknown activity.[1] Another method is the Target Screening. Let us discuss it giving an example. In a screening test, a procedure was set up to discover the cell wall biosynthesis inhibition activity since most of the antibiotics act by disrupting microbial cell wall. In the first phase, screening is done for metabolites. The result is the inhibition of Bacillus subtilis but not Acholeplasma laidlawii. Since, the latter doesn't contain cell wall. In the second phase, substances were sought which inhibited the synthesis of meso-diaminopimelic acid, an important cell wall constituent in bacteria but did not inhibit leucine incorporation which is important in protein synthesis. Finally, substances with Molecular Weights greater than 1000 were eliminated because mostly they elicit side effects. Thus, through this procedure, 10,000 strains were eliminated out of which a new antibiotic, azureomycin was discovered.[3] Ref: 1. http://www.htscreening.org/ accessed on 7th Feb 2011. 2. Industrial Microbiology by L.E.Casida, Jr, Reprint Edition: 2007, NEW AGE INTERNATIONAL (P) LIMITED PUBLISHERS, NEW DELHI, Page no: 55. 3. Biotechnology - A Text Book of Industrial Microbiology by Wulf Crueger and Anneliese Crueger, Second edition, Panima Publishing Corporation, New Delhi/Bangalore,Page no: 4-7 THIS BLOG DOES NOT CONTAIN ANY PLAGIARIZED MATERIAL