BIOG 1106 - Unit 4 Slides / slide 12

Slide 12.

E. coli bacteria. Colored scanning electron micrograph (SEM) of Escherichia coli (E. coli) bacteria. These Gram-negative bacilli (rod-shaped) bacteria are normal inhabitants of the human intestine, and are usually harmless. However, under certain conditions their numbers may increase to such an extent that they cause infection. They cause 80% of all urinary tract infections, travelers' diarrhea, particularly in tropical countries & gastroenteritis in children. They are also widely used in genetic research. Magnification: x8200 at 6x7cm size.	False color TEM of Bacillus subtilis, showing an individual, rod-shaped, gram-positive bacterium beginning to divide by binary fission. The densely colored cell wall (pink) appears pinched at the point of division. B. subtilis also propagates itself by producing endospores (resting cells) which germinate and give rise to vegetative cells. The species is occasionally pathogenic in man, causing severe eye infections (iridocyclitis or panophthalmitis), Credit: CNRI / Photo Researchers, Inc.
Scanning electron micrograph (SEM) of Bacillus thuringiensis. Bacillus thuringiensis was discovered in Germany in 1911 as a pathogen of flour moths from the province of Thuringia. As a commercial insecticide it was used in France in 1938 and in the USA in the 1950s. Spraying or dusting plants with spores of this bacterium appear to be environmentally safe ways to attack such pests as the gypsy moth, the tent caterpillar, and the tobacco hornworm (which also attacks tomatoes). Bacillus thuringiensis is considered safe to humans. When Bacillus thuringiensis creates spores, it also creates toxic protein crystals. They kill larvae which ingest the bacterium and thus the toxin. (Microscope magnification: 13,000x, image width: 9.85 micrometers.) Credit: Scimat / Photo Researchers, Inc.	Color enhanced scanning electron micrograph (SEM) of Bacillus anthracis in lung tissue. Bacillus anthracis is a spore-forming bacterium that causes the anthrax disease in the skin (cutaneous), lungs (inhalation), and digestive system (gastrointestinal). Symptoms of inhalation anthrax begin like those of a cold or flu and progress to include chest discomfort, cough, shortness of breath, tiredness, and muscle aches. Antibiotics are used to treat anthrax and a vaccine is available. Magnification: 20,000x. Credit: Chris Bjornberg / Photo Researchers, Inc.