microbiology and parasitology

• Viruses can only replicate within living host cells.
• A Fortunate Accident—Antibiotics were discovered by accident when Alexander Fleming observed a clear area around a mold that inhibited bacterial growth.
• The first antibiotic, penicillin, was produced by a fungus and was identified as Penicillium notatum (later renamed Penicillium chrysogenum).
• Penicillin is an antibiotic produced by a fungus.
• The usefulness of penicillin was not apparent until the 1940s, when it was finally tested clinically and mass produced.
• Thousands of other antibiotics have been discovered since these early discoveries.
• The diseases we have mentioned are caused by viruses, bacteria, protozoa, and prions—types of microorganisms.
• Microbiologists use specific techniques and procedures to study the microbes that cause diseases such as AIDS and diarrhea, and diseases that have yet to be discovered.
• The body responds to microbial infection in specific ways, and certain drugs combat microbial diseases.
• This book introduces you to the enormous variety of microscopic organisms.
• Microbes play many beneficial roles in the world around us.
• Many antimicrobial chemicals are too toxic to humans for practical use; they kill the pathogenic microbes, but they also damage the infected host.
• Toxicity to humans is a particular problem in the development of drugs for treating viral diseases because viral growth depends on life processes of normal host cells.
• There are very few successful antiviral drugs because a drug that would interfere with viral reproduction would also likely affect uninfected cells of the body.
• Over the years, more and more microbes have developed resistance to antibiotics that at one time were very effective against them.
• Drug resistance results from genetic changes in microbes that enables them to tolerate a certain amount of an antibiotic that would normally inhibit them.
• The recent appearance of vancomycin-resistant Staphylococcus aureus and Enterococcus faecalis has alarmed health care professionals because it indicates that some previously treatable bacterial infections may soon be impossible to treat with antibiotics.
• The groundwork laid during the Golden Age of Microbiology provided the basis for several monumental achievements during the twentieth century.
• New branches of microbiology were developed, including immunology and virology.
• The development of a set of new methods called recombinant DNA technology has revolutionized research and practical applications in all areas of microbiology.
• Bacteriology, the study of bacteria, began with van Leeuwenhoek’s first examination of tooth scrapings.
• Many bacteriologists, like Pasteur, look at the roles of bacteria in food and the environment.
• One intriguing discovery came in 1997, when Heide Schulz discovered a bacterium large enough to be seen with the unaided eye (0.2 mm wide) named Thiomargarita namibiensis.
• Bacterial enzymes are used in drain cleaners to remove clogs without adding harmful chemicals to the environment.
• In some cases, microorganisms indigenous to the environment are used; in others, genetically modified microbes are used.
• Bacteria are used in bioremediation to remove toxins from underground wells, chemical spills, toxic waste sites, and oil spills, such as the massive oil spill from an offshore drilling rig in the Gulf of Mexico on April 20, 2010.
• Among the most commonly used microbes are certain species of bacteria of the genera Pseudomonas and Bacillus.
• Recombinant DNA technology, a revolution in biotechnology, has expanded the potential of bacteria, viruses, and yeast cells and other fungi as miniature biochemical factories.
• Biotechnology, the use of microorganisms to produce some common foods and chemicals, has been used in some form for centuries, but techniques have become much more sophisticated in the past few decades.
• Recombinant DNA techniques have been used thus far to produce a number of natural proteins, vaccines, and enzymes.
• Gene therapy, inserting a missing gene or replacing a defective one in human cells, is a medical application of recombinant DNA techniques.
• Genetically altered strains of bacteria have been developed to protect fruit against frost damage, and bacteria are being modified to control insects that damage crops.
• Recombinant DNA has also been used to improve the appearance, flavor, and shelf life of fruits and vegetables.
• Bacillus enzymes are also used in household detergents to remove spots from clothing.
• Insects can cause devastating crop damage and insect pest control is important for both agriculture and the prevention of human disease.
• Cultured plant and animal cells, as well as intact plants and animals, are also used as recombinant cells and organisms.
• Potential agricultural uses of recombinant DNA include drought resistance, resistance to insects and microbial diseases, and increased temperature tolerance in crops.
• The applications of recombinant DNA technology are increasing with each passing year.
• The toxin gene from Bacillus thuringiensis has been inserted into some plants to make them insect resistant.
• The bacterium Bacillus thuringiensis has been used extensively in the United States to control such pests as alfalfa caterpillars, bollworms, corn borers, cabbageworms, tobacco budworms, and fruit tree leaf rollers.