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11/2 環境污染評估 – 個體、族群、群聚及生態系層次 輔助教材影片: 肝不好,人生是黑白的?. Prevention from self-digestion Surface cells of mucosa secrete slightly alkaline mucus (chemical barrier). 2. Tight junctions between the epithelial cells preventing the diffusion of hydrogen ions into tissues.
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11/2 環境污染評估 – 個體、族群、群聚及生態系層次 輔助教材影片: 肝不好,人生是黑白的?
Prevention from self-digestion • Surface cells of mucosa secrete slightly alkaline mucus (chemical barrier). • 2. Tight junctions between the epithelial cells preventing the diffusion of hydrogen ions into tissues. • 3. Damaged epithelial cells replaced every few days.
Ulcers 1. Stomach (x), duodenum (10x), esophagus. 2. Formation factors: genetic susceptibility, drugs, alcohol, bile salts, secretion of acid and pepsin, bacterium (Helicobacter pylori), stress (parasympathetic nerves stimulating acid secretion).
Bivalve Mizuhopecten yessoensis (kidney → Hepatonpancreas →Gills →Mantle →Muscle) Uptake of Pb by tissues of the mussel Mytilus edulis with different lead compounds (Clark, 1997). Entered compound ↓ Modified toxicity ↓ Non/less toxic or More toxic MFO – mixed function oxidase systems 酵素系統(from Rand, 1995) 不同地點蚵岩螺的cytochrome P450含量
Phase II reactions in Glutathione s-transferase Epoxide hydrolase UDP-Glucuronosyltransferase Sulfotransferases
Impacts on the individual level :Lethal effects Death ︰Sublethal effects Physiological stress Tumours Developmental abnormalities
Measuring changes at individual level ︰Lethal effects (LE) Measurement of toxicity – LT50 (median lethal time) LC50 (median lethal concentration) LD (dosage) LE50, LE100, LE1 (effectiveness)
Cumulative percentage mortality of mussels, Mytilus in (I) 10-2M, (ii) 10-3M, (iii) 10-5M, (iv) 10-6M solution of zinc sulphate (Clark, 1997). Influence of temperature and salinity on the 240H LC50 for Cd to the fiddler crab Uca pugilator (Clark, 1997).
Measuring changes at individual level - Sublethal effects ‧Molecular biomarkers, e.g. Detoxication (detoxification) – metallothioneins mixed function oxygenases (MFO) other detoxication enzymes Heat shock proteins ‧Pysiological responses, e.g. Scope for growth, activity
MFO –mixed function oxygenase systems酵素系統(from Rand, 1995)
Phase II reaction enzymes, e.g. Glutathione s-transferase Epoxide hydrolase UDP-Glucuronosyltransferase Sulfotransferases
Alternative grading options • Change the proportions of general, • mid- and final reports ? • 2. Change the way of general exam? • 3. More to discuss ?