Pertussis toxin "Bordetella" is that "B. pertussis" produces PT and the other species do not. "Bordetella parapertussis" shows the most similarity to "B. pertussis" and was therefore used for research determining the role of PT in causing the typical symptoms of whooping cough. Rat studies showed the development of paroxysmal coughing, a characteristic for whooping cough, occurred in rats infected with "B. pertussis". Rats infected with "B. parapertussis" or a PT-deficient mutant of "B. pertussis" did not show this symptom; neither of these two strains produced PT. A large group of bacterial exotoxins are referred to as "A/B toxins", in essence because
Alexander disease older patients, bulbar or pseudobulbar symptoms and spasticity predominate. Symptoms of the adult form may also resemble multiple sclerosis. No more than 500 cases have been reported. Alexander disease Alexander disease is one of a group of neurological conditions known as the leukodystrophies, which are ailments caused by anomalies in the myelin, which protects nerve fibers in the brain. According to the National Institute of Neurological Disorders and Stroke, the destruction of white matter is accompanied by the formation of Rosenthal fibers—abnormal clumps of protein that accumulate in astrocytes in the brain. The most common type of Alexander disease is