Biotechnology-going to make world evergreen....
Friday 16 July 2010
BIOINFORMATICS- AN INTRODUCTION
In this post , i am going to write some basic introduction regarding bioinformatics.
The first step of the human genome sequencing project has involved identifying those DNA sequences which code for proteins synthesised by the cell and hence which define its function. For this reason researchers have been isolating the mRNAs expressed in cells, converting them to DNA (cDNA), cloning them and sequencing them in their 1000s. These expressed sequences are given the name of EST (Expressed Sequence Tag). As the sequencing of the human genome progresses the function of more and more DNA/protein sequences are identified. Therefore, it is now routine to generate many ESTs and then to compare them with sequences in the databases to determine their function.
Let us take this EST which is given below:
1 gaacgacctctctcaggcttagcctgggctgtagctatgataaaccggcaggagattggt ggacctcgctcttataccatcgcagttgcttccctgggtaaaggagtggcctgtaatcct gcctgcttcatcacacagctcctccctgtgaaaaggaagctagggttctatgaatggact tcaaggttaagaagtcacataaatcccacaggcactgttttgcttcagctagaaaataca
This part of the practical illustrates how to compare DNA sequences against the DNA databanks using BLAST (Basic Local Alignment Search Tool) to find out what they code for.
1.Copy the relevant sequence onto the clipboard.
2.Click here to go to Sequence Search at NCBI (http://www.ncbi.nlm.nih.gov/BLAST):
3.An NCBI BLAST page will be returned .In that choose the option such as below:
4.Choose the ‘nucleotide blast’ option.
5.A page will be returned with a query window.
6.Paste the sequence into the window.
7.Under ‘Choose Search Set’ set to ‘Nucleotide collection (nr/nt)’.
8.Press the BLAST button and wait while the sequence is compared to the databases and the matches displayed.
9.A page is returned indicating that the ID request and that the search has been placed in a queuing system.
10.Carefully study the output.
INTERPRETATION OF BLAST RESULTS
1. A page will be returned with the results from BLAST search. These are presented both graphically and textually.
2. The graphical view shows the query sequence as a thick red line with base numbers attached to it. Below this are a series of coloured thin lines that represent matches to the query sequence. The length of the line indicates that part of the query sequence which matches the hit sequence. The colour represents the quality of the match.
3. The textual view is found below the picture. It is a list of files that correspond to the visual display matches and sorted in match quality order.
The first hyperlink is to the file containing the entire sequence. If you click on this hyperlink you can view the actual sequence file and information on the sequence it contains (e.g. what it codes for, organism source, repeat regions if any etc ,
4. To display a FASTA version of the file, in the drop down menu next to ‘Display’, click on FASTA and then click ‘Display’. The file for the same gene is now in FASTA format – a format that is used as an input for many different computer programs.
5. This is followed by a very brief description of the file. This description is taken from the sequence file.
6. The next number is a numerical score (Score - bits) which represents a statistical measure of how good the match was (the greater the score the better the match). This score is hyperlinked to the actual match found between your query sequence and the match itself.
Finally the Expect value (E) is a parameter that describes the number of hits one can "expect" to see just by chance when searching a database of a particular size. Essentially, it describes the random background noise that exists for matches between sequences
Exercise for practice
If you want to practice some query sequence,you can just try these sequences given below.
1.tgtgttttatgtcttctacgaacagtacctgaccatcattgacgacactatcttcaacct cggtgtgtccctgggcgcgatatttctggtgaccatggtcctcctgggctgtgagctctg gtctgcagtcatcatgtgtgccaccatcgccatggtcttggtcaacatgtttggagttat gtggctctggggcatcagtctgaacgctgtatccttggtcaacctggtgatg
2.tggtccctatgggcttccgcacatgccgcgggcggccaggcaacgtgcgtgtctctgcca tgtggcagaagtgctctttgtggcagtggccaggcagggagtgtctgcagtcctggtggg gctgagcctgaggccttccagaaagcaggagcagctgtgctgcaccccatgtgggtgacc aggtcctttctcctgatagtcacctgctggttgttgccaggttgcagctgctcttgcatc
3.cccaaatgaagtgtgaacgtgatgttttcggatgcaaactcagctcagggattcattttg tgtcttagttttatatgcatccttatttttaatacacctgcttcacgtccctatgttggg aagtccatatttgtctgcttttcttgcagcatcatttccttacaatactgtccggtggac aaaatgacaattgatatgtttttctgatataattactttagctgcactaacagtacaatg
Wednesday 30 June 2010
BIOLUMININESCENCE
Bioluminescence in Biotechnology
Bioluminescent organisms are a target for many areas of research. Luciferase systems are widely used in the field of genetic engineering as reporter genes. Luciferase systems have also been harnessed for biomedical research using bioluminescence imaging.Vibrio symbiosis with numerous marine invertebrates and fish, namely the Hawaiian Bobtail Squid (Euprymna scolopes), are key experimental model for symbiosis, quorum sensing, and bioluminescence.The structure of photophores, the light producing organs in bioluminescent organisms, are being investigated by industrial designers.
All cells produce some form of bioluminescence within the electromagnetic spectrum, but most are neither visible nor noticeable to the naked eye. Every organism's bioluminescence is unique in wavelength, duration, timing and regularity of flashes.
Application
Glowing trees to line highways to save government electricity bills
Christmas trees that do not need lights, reducing danger from electrical fires
Agricultural crops and domestic plants that luminesce when they need watering New methods for detecting bacterial contamination of meats and other foods
Bio-identifiers for escaped convicts and mental patients
Detecting bacterial species in suspicious corpses
Novelty pets that bioluminesce (rabbits, mice, fish etc.)
example : every living organism on Pandora is bioluminescent.
Tuesday 29 June 2010
An Introduction to stem cells
Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.
Stem cells are distinguished from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.
Until recently, scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. The functions and characteristics of these cells will be explained in this document. Scientists discovered ways to derive embryonic stem cells from early mouse embryos nearly 30 years ago, in 1981. The detailed study of the biology of mouse stem cells led to the discovery, in 1998, of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through in vitrofertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. This new type of stem cell, called induced pluripotent stem cells (iPSCs), will be discussed in a later section of this document.
Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lung, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.
Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.
Laboratory studies of stem cells enable scientists to learn about the cells’ essential properties and what makes them different from specialized cell types. Scientists are already using stem cells in the laboratory to screen new drugs and to develop model systems to study normal growth and identify the causes of birth defects.
Research on stem cells continues to advance knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.
Stem cells differ from other kinds of cells in the body. All stem cells—regardless of their source—have three general properties: they are capable of dividing and renewing themselves for long periods; they are unspecialized; and they can give rise to specialized cell types
An adult stem cell is thought to be an undifferentiated cell, found among differentiated cells in a tissue or organ that can renew itself and can differentiate to yield some or all of the major specialized cell types of the tissue or organ. The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found. Scientists also use the term somatic stem cell instead of adult stem cell, where somatic refers to cells of the body (not the germ cells, sperm or eggs). Unlike embryonic stem cells, which are defined by their origin (the inner cell mass of the blastocyst), the origin of adult stem cells in some mature tissues is still under investigation.
Adult stem cells have been identified in many organs and tissues, including brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, ovarian epithelium, and testis.
USES OF STEMCELLS
There are many ways in which human stem cells can be used in research and the clinic. Studies of human embryonic stem cells will yield information about the complex events that occur during human development. A primary goal of this work is to identify howundifferentiated stem cells become the differentiated cells that form the tissues and organs. Scientists know that turning genes on and off is central to this process. Some of the most serious medical conditions, such as cancer and birth defects, are due to abnormal cell division and differentiation. A more complete understanding of the genetic and molecular controls of these processes may yield information about how such diseases arise and suggest new strategies for therapy. Predictably controlling cell proliferation and differentiation requires additional basic research on the molecular and genetic signals that regulate cell division and specialization. While recent developments with iPS cells suggest some of the specific factors that may be involved, techniques must be devised to introduce these factors safely into the cells and control the processes that are induced by these factors.
Human stem cells could also be used to test new drugs. For example, new medications could be tested for safety on differentiated cells generated from human pluripotent cell lines. Other kinds of cell lines are already used in this way. Cancer cell lines, for example, are used to screen potential anti-tumor drugs. The availability of pluripotent stem cells would allow drug testing in a wider range of cell types. However, to screen drugs effectively, the conditions must be identical when comparing different drugs. Therefore, scientists will have to be able to precisely control the differentiation of stem cells into the specific cell type on which drugs will be tested. Current knowledge of the signals controlling differentiation falls short of being able to mimic these conditions precisely to generate pure populations of differentiated cells for each drug being tested.
Perhaps the most important potential application of human stem cells is the generation of cells and tissues that could be used for cell-based therapies. Today, donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs far outweighs the available supply. Stem cells, directed to differentiate into specific cell types, offer the possibility of a renewable source of replacement cells and tissues to treat diseases including Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
For example, it may become possible to generate healthy heart muscle cells in the laboratory and then transplant those cells into patients with chronic heart disease. Preliminary research in mice and other animals indicates that bone marrow stromal cells, transplanted into a damaged heart, can have beneficial effects. Whether these cells can generate heart muscle cells or stimulate the growth of new blood vessels that repopulate the heart tissue, or help via some other mechanism is actively under investigation. For example, injected cells may accomplish repair by secreting growth factors, rather than actually incorporating into the heart. Promising results from animal studies have served as the basis for a small number of exploratory studies in humans (for discussion, see call-out box, "Can Stem Cells Mend a Broken Heart?"). Other recent studies in cell culturesystems indicate that it may be possible to direct the differentiation of embryonic stem cells or adult bone marrow cells into heart muscle cells.
GM food- A boon or ban
Environmental activists, religious organizations, public interest groups, professional associations and other scientists and government officials have all raised concerns about GM foods, and criticized agribusiness for pursuing profit without concern for potential hazards, and the government for failing to exercise adequate regulatory oversight. It seems that everyone has a strong opinion about GM foods. Even the Vatican and the Prince of Wales have expressed their opinions. Most concerns about GM foods fall into three categories: environmental hazards, human health risks, and economic concerns.
Environmental hazards
There are several possible solutions to the three problems mentioned above. Genes are exchanged between plants via pollen. Two ways to ensure that non-target species will not receive introduced genes from GM plants are to create GM plants that are male sterile (do not produce pollen) or to modify the GM plant so that the pollen does not contain the introduced gene. Cross-pollination would not occur, and if harmless insects such as monarch caterpillars were to eat pollen from GM plants, the caterpillars would survive.
Another possible solution is to create buffer zones around fields of GM crops. For example, non-GM corn would be planted to surround a field of B.t. GM corn, and the non-GM corn would not be harvested. Beneficial or harmless insects would have a refuge in the non-GM corn, and insect pests could be allowed to destroy the non-GM corn and would not develop resistance to B.t. pesticides. Gene transfer to weeds and other crops would not occur because the wind-blown pollen would not travel beyond the buffer zone. Estimates of the necessary width of buffer zones range from 6 meters to 30 meters or more. This planting method may not be feasible if too much acreage is required for the buffer zones.
Human health risks
On the whole, with the exception of possible allergenicity, scientists believe that GM foods do not present a risk to human health.
Economic concerns
Bringing a GM food to market is a lengthy and costly process, and of course agri-biotech companies wish to ensure a profitable return on their investment. Many new plant genetic engineering technologies and GM plants have been patented, and patent infringement is a big concern of agribusiness. Yet consumer advocates are worried that patenting these new plant varieties will raise the price of seeds so high that small farmers and third world countries will not be able to afford seeds for GM crops, thus widening the gap between the wealthy and the poor. It is hoped that in a humanitarian gesture, more companies and non-profits will follow the lead of the Rockefeller Foundation and offer their products at reduced cost to impoverished nations.
Patent enforcement may also be difficult, as the contention of the farmers that they involuntarily grew Monsanto-engineered strains when their crops were cross-pollinated shows. One way to combat possible patent infringement is to introduce a "suicide gene" into GM plants. These plants would be viable for only one growing season and would produce sterile seeds that do not germinate. Farmers would need to buy a fresh supply of seeds each year. However, this would be financially disastrous for farmers in third world countries who cannot afford to buy seed each year and traditionally set aside a portion of their harvest to plant in the next growing season. In an open letter to the public, Monsanto has pledged to abandon all research using this suicide gene technology
LABELLING OF GM FOODS
Labeling of GM foods and food products is also a contentious issue. On the whole, agribusiness industries believe that labeling should be voluntary and influenced by the demands of the free market. If consumers show preference for labeled foods over non-labeled foods, then industry will have the incentive to regulate itself or risk alienating the customer. Consumer interest groups, on the other hand, are demanding mandatory labeling. People have the right to know what they are eating, argue the interest groups, and historically industry has proven itself to be unreliable at self-compliance with existing safety regulations. The FDA's current position on food labeling is governed by the Food, Drug and Cosmetic Act which is only concerned with food additives, not whole foods or food products that are considered "GRAS" - generally recognized as safe. The FDA contends that GM foods are substantially equivalent to non-GM foods, and therefore not subject to more stringent labeling. If all GM foods and food products are to be labeled, Congress must enact sweeping changes in the existing food labeling policy.
There are many questions that must be answered if labeling of GM foods becomes mandatory. First, are consumers willing to absorb the cost of such an initiative? If the food production industry is required to label GM foods, factories will need to construct two separate processing streams and monitor the production lines accordingly. Farmers must be able to keep GM crops and non-GM crops from mixing during planting, harvesting and shipping. It is almost assured that industry will pass along these additional costs to consumers in the form of higher prices.
Secondly, what are the acceptable limits of GM contamination in non-GM products? The EC has determined that 1% is an acceptable limit of cross-contamination, yet many consumer interest groups argue that only 0% is acceptable. Some companies such as Gerber baby foods and Frito-Lay have pledged to avoid use of GM foods in any of their products. But who is going to monitor these companies for compliance and what is the penalty if they fail? Once again, the FDA does not have the resources to carry out testing to ensure compliance.
What is the level of detectability of GM food cross-contamination? Scientists agree that current technology is unable to detect minute quantities of contamination, so ensuring 0% contamination using existing methodologies is not guaranteed. Yet researchers disagree on what level of contamination really is detectable, especially in highly processed food products such as vegetable oils or breakfast cereals where the vegetables used to make these products have been pooled from many different sources. A 1% threshold may already be below current levels of detectability.
Finally, who is to be responsible for educating the public about GM food labels and how costly will that education be? Food labels must be designed to clearly convey accurate information about the product in simple language that everyone can understand. This may be the greatest challenge faced be a new food labeling policy: how to educate and inform the public without damaging the public trust and causing alarm or fear of GM food products.
In January 2000, an international trade agreement for labeling GM foods was established. More than 130 countries, including the US, the world's largest producer of GM foods, signed the agreement. The policy states that exporters must be required to label all GM foods and that importing countries have the right to judge for themselves the potential risks and reject GM foods, if they so choose. This new agreement may spur the U.S. government to resolve the domestic food labeling dilemma more rapidly.
Sunday 27 June 2010
India's Top 10 Biotech companies
1.Serum Institute of India
2.Biocon
3.Panacea Biotech
4.Monsanto Biotech
5.Rasi Seeds
6.Venkateshwara Hatcheries
7.Novo Nordisk
8.Tulip
9.Indian Immunologicals
10.TransAsia
Courtesy: BioSpectrum Magazine, www.biospectrum.ciol.com
WORLD'S TOP 10 BIOTECH COMPANIES
1.Amgen
2.Genentech
3.Serono
4.Biogen Idec
5.UCB-Celltech
6.Genzyme
7.Gilead
8.MedImmune
9.Chiron
10.Millennium
courtesy: BUSINESS INSIGHTS