DNA Recombination, Biotechnology, and Genetic Engineering
DNA Recombination
DNA recombination is a process that allows the combination of DNA fragments from different origins. This can be done in a laboratory using cellular machinery and enzymes. DNA can be cut into fragments using enzymes called restriction endonucleases. The resulting fragments have cohesive or sticky edges complementary to other DNA cut with the same enzyme, so you can join different fragments of recombinant DNA origin. In this way, it is possible to introduce DNA into the genome of
Read MoreAlternative Toxicity Assays: Replacing Rodent Models
Describe 5 alternative toxicity assays that complement or might be able to replace rodent assays
Several alternatives to the traditional rodent bioassay have been proposed, of which the most promising are non-animal assays such as quantitative structure-activity relationship expert systems, in vitro assays, the use of cDNA microarrays to detect genetic expression changes, human clinical trials, & epidemiological research.
- QSAR expert systems, particularly for initial screening, should be further
Cellular Membrane and Extracellular Matrix: Structure and Function
Cellular Membrane: Structure and Function
The cellular membrane is a structure common to all cells of living beings. It surrounds a portion of cytoplasm (cytoplasmic membrane). The same membranous structure also delimits most internal cell structures. Biological membranes (plasma membrane or internal membranes of the cell) are called unitary membranes.
Structure
A clear strip (osmiophobic), bordered by two dark stripes (osmiophilic).
Composition
- Membrane Lipids: Phospholipids, cholesterol, and glycolipids.
3Rs Alternatives: Reduction, Refinement, and Replacement in Animal Testing
The 3Rs in Animal Research
Reduction: Fewer animals used to obtain information of a given amount and precision.
Refinement: Less painful procedures applied to animals necessarily used.
Replacement: Substitution of conscious living vertebrates by non-sentient material.
Reduction Alternatives
Good planning of studies:
- Rational & efficient use of animals:
- No wasting
- Pilot studies
- Screening tests
- Proper statistical design
- Use of inbred strains (for some study types)
Refinement Alternatives
Minimized potential
Read MoreLipid Oxidation and Prevention in Food
Caramelization
Caramelization is the degradation of sugars without the presence of amino acids or proteins, heated above its melting point (pyrolysis). This process forms a series of volatile and non-volatile substances, with a characteristic taste and dark brown color.
Alteration of Lipids
Alteration of food lipids leads to changes in organoleptic and nutritional characteristics. It subsequently decreases shelf life and generates toxic products, leading to consumer rejection and potential health risks.
Read MoreDrinking Water Quality Standards: Microbiological, Chemical, and Radioactive Parameters
Drinking Water Quality Standards
Type I: Microbiological Parameters and Turbidity
Criteria for microbiological parameters and turbidity:
- Microbiological Contamination Indicator Microorganisms: Microorganisms from the coliform group are a good indicator of microbial water quality. Water must meet the following characteristics:
- For all samples analyzed monthly, a drinking water service accepts the presence of total coliform in:
- One sample when fewer than 10 samples are analyzed in the month.
- 10% of the
- For all samples analyzed monthly, a drinking water service accepts the presence of total coliform in: