This gene controls the operator gene in cooperation with a chemical substance called inducer present in the cytoplasm. A regulator gene is not necessarily adjacent to the operator gene which it controls. The regulator gene codes for and produces a protein called repressor.
The Gram-positive bacteria include staphylococci (staph), streptococci (strep), pneumococci, and the bacterium responsible for diphtheria (Cornynebacterium diphtheriae) and anthrax (Bacillus anthracis). The Danish bacteriologist J.M.C. Gram (1853-1938) devised a method of staining bacteria using a dye called crystal (gentian) violet. Gram's method helps distinguish between different types of bacteria. The gram-staining characteristics of bacteria are denoted as positive or negative, depending upon whether the bacteria take up and retain the crystal violet stain or not.
Gram-positive bacteria retain a purple-colored stain, while Gram-negative bacteria appear pinkish or red. Gram-negative bacteria can cause many types of infections and are spread to humans in a variety of ways. Several species, including Escherichia coli, are common causes of foodâborne disease.Vibrio cholerae âthe bacteria responsible for choleraâis a waterborne pathogen. Gram-negative bacteria can also cause respiratory infections, such as certain types of pneumonia, and sexually transmitted diseases, including gonorrhea.Yersinia pestis, the Gram-negative bacterium responsible for plague, is transmitted to people through the bite of an infected insect or handling an infected animal.ram-positive bacteria retain a purple-colored stain, while Gram-negative bacteria appear pinkish or red. Gram-negative bacteria can cause many types of infections and are spread to humans in a variety of ways. Several species, including Escherichia coli, are common causes of foodâborne disease.