biot 4th

• The chief traditional biotechnologies have been aquaculture
• Modern marine biotechnology


  Although still in its infancy, encompasses such new technologies as protein engineering
• The marine environment covers almost 71% of the earth's surface and contains 97% of the available water
• The oceans play an important role in global ecology
• The oceans regulate levels of carbon dioxide and recycle 90% of the world's carbon in the marine food web
• A number of people depend on the biological diversity in the oceans
• In Asia alone, fish is a main protein staple for more than one billion people
• The oceans are an ancient ecosystem where life, in the form of bacteria, originated about four billion years ago
• Marine organisms are of great interest to scientists and industry
• In many regions of the world overfishing has seriously reduced fish and shellfish stocks
• Salt water, or marine, culture


  Called mariculture
• Ancient aquaculture


  Primarily freshwater
• As methods were refined, polyculture was practiced, combining species with different food preferences; ponds contained varieties of finfish, shellfish, or crustaceans
• An aquaculturist must know the chemical composition of the soil where the pond will be situated, the amount and type of water to be used, and the type and quantity of animal feed necessary for maximum production
• A variety of methods exist, from rearing in tanks to using floating platforms and substrates for the growth of organisms
• Genetic manipulation in culture

  Promotes faster growth and maturation, increased disease resistance, and triploidy
• Normal diploid oysters spawn in the summer and lose their flavor because they form a massive amount of reproductive tissue
• Triploid oysters


  Have three sets of chromosomes (two from the female and one from the male), are sterile and do not form reproductive organs, are more flavorful and meatier
• Obtaining triploid oysters

  Treating eggs with cytochalasin B to inhibit normal cell division and double the number of chromosomes, then fertilizing with normal sperm
• Concerns about the safety of using cytochalasin B may soon lead to the production of triploid oysters by mating tetraploids (having four sets of chromosomes) and normal diploid oysters
• Bivalves such as oysters and gastropods such as abalone are cultured by the manipulation of the reproductive cycle
• Inducing spawning in bivalves and gastropods

  1. Adding hydrogen peroxide to the seawater to trigger synthesis of prostaglandin, a hormone that triggers spawning

  2. Adding the amino acid aminobutyric acid (GABA) to induce larval settlement
• High densities of animals in aquaculture increase the chance of disease
• Bacterial control in aquaculture


  Using antibacterial agents such as disinfectants and antibiotics (tetracycline, chloramphenicol, penicillin, etc.) in ponds or culturing pens
• The heavy use of antibiotics poses an ultimate risk to human health
• Antibiotic residues could remain in the fish, crustacean, or bivalve consumed by humans
• Protozoans such as flagellates and ciliates may not kill the fish but can cause extensive damage by feeding on parts of the fish so that it can no longer be used for food
• Viral diseases pose a particularly difficult problem for fish aquaculture facilities
• Infected animals often become carriers and must be destroyed
• Developing a recombinant vaccine against IHN (Infectious Hematopoietic Necrosis)

  1. Isolating and expressing genes encoding viral proteins to induce antibody formation in fish

  2. Delivering the vaccine by injection or immersion in water

  3. Using ultrasound for approximately 10 minutes to facilitate vaccine delivery
• The development of new vaccines and efficient delivery systems will enhance productivity from the egg through larval stages (a risky part of the life cycle)
• Biotechnology can also be used against the spread of disease in aquaculture through the development of diagnostics
• If diseases can be detected early, before they spread, timely preventive measures can be taken, and infected organisms can be removed
• The three major groups of eukaryotic macroalgae

  • Green (Chlorophyta)
  • Red (Rhodophyta)
  • Brown (Phaeophyta)
• Kelp was used as fertilizer and source of potash and acetone for the production of explosives
• Alginates are the main structural compositions of the cell wall and intercellular matrix of brown seaweeds
• The red alga Porphyra, or nori, has been cultured as a food source in Japan since 1570
• Wakame and kombu have a variety of commercial applications; they use noodles, soups, and salads, or with meats
• Alginic acids (alginates) from brown algae and phycocolloid polysaccharides (agars, carrageenans) were extracted for iodine in the mid-nineteenth century
• Alginic acids and phycocolloid polysaccharides are used in food