What are DNA Probes?
Little more than a decade ago, toxic phytoplankton monitoring with DNA probes was still in the realm of science fiction. Today it is a reality. Probes for some key micro-algae are already in commercial use and ultimately DNA probes could become a major HAB monitoring tool.
What exactly are they?
DNA probes have been in use for more than a decade in medicine and dentistry, but they have only recently been developed with the aquaculture industry in mind. The DNA of a selected micro-alga is sequenced, and the sequence of nucleotides that makes up its genetic code is compared with that of other related algae using readily available computer software packages. Unique nucleotide "signatures" (usually between 15 and 50 nucleotides) are selected to develop into probes. The ribosomal RNA (rRNA) of the cell is targeted because it is abundant in cells and so good recognition, or a good "hit", is ensured. The probes will have some "tag", for example fluorescein, attached for easy recognition of a positive assay. The probes can be prepared for a number of different assay systems, but require intensive trialling to ensure there is no cross-reactivity with other micro-algae species.
Pseudo-nitzschia and Alexandrium whole cell format DNA probes are now used routinely in New Zealand's phytoplankton monitoring programmes as an aid to risk management decision-making, and the monitoring laboratory (Cawthron Institute) is approved by International Accreditation New Zealand (recognised under ISO17025).
How are they used?
Identification of micro-algae to species level is vital so that shellfish growers, and health and industry officials, can make safe and economically sound harvesting decisions.
Standard phytoplankton monitoring methods involve identifying toxic species in a water sample and counting them. It is labour intensive and requires expert training in the recognition of the critical algae. In some case scanning electron microscope preparation of samples can be required to differentiate species. This can be expensive and cause delays. DNA probes offer an exciting and rapid alternative
http://www.geneprobes.org/whatare.htm
Thursday, June 28, 2007
Saturday, June 23, 2007
Know more about genetic modified food...
What are Genetically Modified (GM) Foods?
GM is a special set of technologies that alter the genetic makeup of such living organisms as animals, plants, or bacteria. Biotechnology, a more general term, refers to using living organisms or their components, such as enzymes, to make products that include wine, cheese, beer, and yogurt.
Combining genes from different organisms is known as recombinant DNA technology, and the resulting organism is said to be "genetically modified," "genetically engineered," or "transgenic." GM products (current or in the pipeline) include medicines and vaccines, foods and food ingredients, feeds, and fibers.
Locating genes for important traits—such as those conferring insect resistance or desired nutrients—is one of the most limiting steps in the process. However, genome sequencing and discovery programs for hundreds of different organisms are generating detailed maps along with data-analyzing technologies to understand and use them.
History.....
In 2003, about 167 million acres (67.7 million hectares) grown by 7 million farmers in 18 countries were planted with transgenic crops, the principal ones being herbicide- and insecticide-resistant soybeans, corn, cotton, and canola. Other crops grown commercially or field-tested are a sweet potato resistant to a virus that could decimate most of the African harvest, rice with increased iron and vitamins that may alleviate chronic malnutrition in Asian countries, and a variety of plants able to survive weather extremes.
On the horizon are bananas that produce human vaccines against infectious diseases such as hepatitis B; fish that mature more quickly; fruit and nut trees that yield years earlier, and plants that produce new plastics with unique properties.
In 2003, countries that grew 99% of the global transgenic crops were the United States (63%), Argentina (21%), Canada (6%), Brazil (4%), and China (4%), and South Africa (1%). Although growth is expected to plateau in industrialized countries, it is increasing in developing countries. The next decade will see exponential progress in GM product development as researchers gain increasing and unprecedented access to genomic resources that are applicable to organisms beyond the scope of individual projects.
GM food....effects......
Technologies for genetically modifying (GM) foods offer dramatic promise for meeting some areas of greatest challenge for the 21st century. Like all new technologies, they also poses some risks, both known and unknown. Controversies surrounding GM foods and crops commonly focus on human and environmental safety, labeling and consumer choice, intellectual property rights, ethics, food security, poverty reduction, and environmental conservation
GM is a special set of technologies that alter the genetic makeup of such living organisms as animals, plants, or bacteria. Biotechnology, a more general term, refers to using living organisms or their components, such as enzymes, to make products that include wine, cheese, beer, and yogurt.
Combining genes from different organisms is known as recombinant DNA technology, and the resulting organism is said to be "genetically modified," "genetically engineered," or "transgenic." GM products (current or in the pipeline) include medicines and vaccines, foods and food ingredients, feeds, and fibers.
Locating genes for important traits—such as those conferring insect resistance or desired nutrients—is one of the most limiting steps in the process. However, genome sequencing and discovery programs for hundreds of different organisms are generating detailed maps along with data-analyzing technologies to understand and use them.
History.....
In 2003, about 167 million acres (67.7 million hectares) grown by 7 million farmers in 18 countries were planted with transgenic crops, the principal ones being herbicide- and insecticide-resistant soybeans, corn, cotton, and canola. Other crops grown commercially or field-tested are a sweet potato resistant to a virus that could decimate most of the African harvest, rice with increased iron and vitamins that may alleviate chronic malnutrition in Asian countries, and a variety of plants able to survive weather extremes.
On the horizon are bananas that produce human vaccines against infectious diseases such as hepatitis B; fish that mature more quickly; fruit and nut trees that yield years earlier, and plants that produce new plastics with unique properties.
In 2003, countries that grew 99% of the global transgenic crops were the United States (63%), Argentina (21%), Canada (6%), Brazil (4%), and China (4%), and South Africa (1%). Although growth is expected to plateau in industrialized countries, it is increasing in developing countries. The next decade will see exponential progress in GM product development as researchers gain increasing and unprecedented access to genomic resources that are applicable to organisms beyond the scope of individual projects.
GM food....effects......
Technologies for genetically modifying (GM) foods offer dramatic promise for meeting some areas of greatest challenge for the 21st century. Like all new technologies, they also poses some risks, both known and unknown. Controversies surrounding GM foods and crops commonly focus on human and environmental safety, labeling and consumer choice, intellectual property rights, ethics, food security, poverty reduction, and environmental conservation
Subscribe to:
Posts (Atom)