A selection of Mechanical calculators: The basic operating principles of mechanical calculators changed little from the end of the 19th century to their obsolescence in the 1970s, though there were many developments in the mechanisms and the materials used.
Post. Share. Bacteriophages are viruses that infect bacteria. A bacteriophage can have a protein tail attached to the capsid (protein coat that envelopes the genetic material), which is used to infect the host bacteria.Scientists have long sought to uncover the structure and function of viruses. bacteriophage can have a protein tail attached to the capsid (protein coat that envelopes the genetic material), which is used to infect the host bacteria.
Harmful bacteria may also emit toxins that damage the body. Common pathogenic bacteria and the types of bacterial diseases they cause include: Escherichia coli and Salmonella cause food poisoning. Helicobacter pylori cause gastritis and ulcers.Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhea.armful bacteria may also emit toxins that damage the body. Common pathogenic bacteria and the types of bacterial diseases they cause include: Escherichia coli and Salmonella cause food poisoning. Helicobacter pylori cause gastritis and ulcers.