《微生物生物学》课程教学资源（书籍文献）World of Microbiology and Immunology，Brigham Narins, Editor，Volumes 1 and 2 A-Z.pdf_P11-P15

WORLD OF MICROBIOLOGY & IMMUNOLOGY Acknowledgments xv Reuters/Archive Photos, Inc. Reproduced by permission.— Mosquito after feeding on human, photograph by Rod Planck. National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.—Novotny, Dr. Ergo, photograph. © Ted Spiegel/Corbis. Reproduced by permission.—Nucleus and perinuclear area-liver cell from rat, photograph by Dr. Dennis Kunkel. Phototake. Reproduced by permission.— Ocean wave curling to the left, photograph. Corbis. Reproduced by permission.—Oil slick on water, photograph. © James L. Amos/Corbis. Reproduced by permission.— Pasteur, Louis, photograph. The Library of Congress.—Patient getting vaccination injection against Hepatitis B, photograph. © Astier Frederik/Corbis Sygma. Reproduced by permission.—Patients at a Turkish Tuberculosis Hospital sit up in their beds, photograph. © Corbis. Reproduced by permission.—Petri dish culture of Klebsiella pneumoniae, photograph. © Lester V. Bergman/Corbis. Reproduced by permission.—Pharmaceutical technician, and scientist, discussing experiment results in laboratory, photograph. Martha Tabor/Working Images Photographs. Reproduced by permission.—Plague of 1665, photograph. Mary Evans Picture Library/Photo Researchers, Inc. Reproduced by permission.— Prusiner, Dr. Stanley B., photograph by Luc Novovitch. Reuters/Archive Photos, Inc. Reproduced by permission.— Raccoon in winter cottonwood, photograph by W. Perry Conway. Corbis Corporation. Reproduced by permission.— Researcher, in biochemistry laboratory using a transmission electron microscope, photograph by R. Maisonneuve. Photo Researchers, Inc. Reproduced by permission.—Resistant Staphyloccoccus Bacteria, photograph. © Lester V. Bergman/Corbis. Reproduced by permission.—Sample in a Petri Dish, photograph. © Bob Krist/Corbis. Reproduced by permission.—Scientists test water samples from a canal, photograph. © Annie Griffiths Belt, Corbis. Reproduced by permission.—Scientists wearing masks hold up beaker in a laboratory of chemicals, photograph. © Steve Chenn/Corbis. Reproduced by permission.—Sheep grazing on field, photograph. © Richard Dibon-Smith, National Audubon Society Collection/Photo Researchers, Inc. Reproduced with permission.—Shelf Fungi on Nurse Log, photograph. © Darell Gulin/Corbis. Reproduced by permission.—Silvestri, Mike, and Neil Colosi, Anthrax, Decontamination Technicians, photograph. © Mike Stocke/Corbis. Reproduced by permission.— Single mammalian tissue culture cell, color transmission electron micrograph. Dr. Gopal Murti/Science Photo Library/Photo Researchers, Inc. Reproduced by permission.—Steam rises from the surface of Yellowstone’s Grand Prismatic Spring, photograph. © Roger Ressmeyer/Corbis. Reproduced by permission.—Steam rising from Therman Pool, photograph. © Pat O’Hara/Corbis. Reproduced by permission.—Streptococcus pyogenes bacteria, colored transmission electron micrograph by Alfred Pasieka. © Alfred Pasieka/Science Photo Library, Photo Researchers, Inc. Reproduced by permission.— Streptococcus viridans Bacteria in petri dish, photograph. © Lester V. Bergman/Corbis. Reproduced by permission.— Surgeons operating in surgical gowns and masks, photograph. © ER Productions/Corbis. Reproduced by permission.— Technician at American type culture collection, photograph. © Ted Spiegel/Corbis. Reproduced by permission.— Technician places culture on agar plates in laboratory, photograph. © Ian Harwood; Ecoscene/Corbis. Reproduced by permission.—The parasitic bacteria Staphylococcus magnified 1000x, photograph. © Science Pictures Limited/Corbis. Reproduced by permission.—The Plague of Florence, photograph. Corbis-Bettmann. Reproduced by permission.—Threedimensional computer model of a protein molecule of matrix porin found in the E. Coli bacteria, photograph. © Corbis. Reproduced by permission.—Three-dimensional computer model of a protein molecule of matrix porin found in the E. Coli bacteria, photograph. © Corbis. Reproduced by permission.—Three-dimensional computer model of the enzyme acetylcholinesterase, photograph. © Corbis. Reproduced by permission.—Three-dimensional computer model of the molecule dihydrofolate reducatase enzyme, photograph. © Corbis. Reproduced by permission.—Three-dimensional computer model of the protein Alzheimer Amyloid B, photograph. © Corbis. Reproduced by permission.—Twenty most common amino acids, illustration by Robert L. Wolke. Reproduced by permission—Two brown mountain sheep, photograph. © Yoav Levy/Phototake NYC. Reproduced by permission.—United States Coast Guard hazardous material workers wearing protective suits work inside the U.S. Senate’s Hart Building, photograph. © AFP/Corbis. Reproduced by permission.—Urey, Harold, photograph. The Library of Congress.—Veterinarian technicians check the blood pressure of a dog, photograph. AP/Wide World Photos. Reproduced by permission.—View of aging wine in underground cellar, photograph. Getty Images. Reproduced by permission.—Virus Plaque in an E. Coli culture, photograph. © Lester V. Bergman/Corbis. Reproduced by permission.—Visual biography of monoclonal antibody development at the Wistar Institute, photograph. © Ted Spiegel/Corbis. Reproduced by permission.—Waksman, Selman Abraham, photograph. Getty Images. Reproduced by permission.—Watson, James and Crick, Francis, photograph. Getty Images. Reproduced by permission.—Watson, James Dewey, photograph. The Library of Congress.—Wind storm on the East Coast, Cape Cod, Massachusetts, photograph. Gordon S. Smith/Photo Researchers, Inc. Reproduced by permission.— Woman clerks wearing cloth masks to protect against influenza, photograph. © Bettmann/Corbis. Reproduced by permission.—Woman scientist mixes chemicals in beaker, photograph. © Julie Houck/Corbis. Reproduced by permission.— Woman sneezing, photograph. © Michael Keller/Corbis. Reproduced by permission.—Young Children lying on beds in tuberculosis camp, photograph. © Bettmann/Corbis. Reproduced by permission. • • womi_fm 5/6/03 1:34 PM Page xv

A 1 • • AAbbe, Ernst BBE, ERNST (1840-1905) German optical engineer Ernst Abbe was among the first optical engineers, designing and perfecting methods for manufacturing microscopes and lens systems of high quality. Though he was a great scientist in his own right, he might have remained anonymous but for the foresight of his employer, Carl Zeiss (1816–1888). In his early twenties Abbe was working as a lecturer in Jena, Germany. He was recognized as being intelligent and industrious, particularly in mathematics, but he was unable to secure a professorial position at the university. In 1855 Zeiss, the owner and operator of a local company that built optical instruments, approached him. Zeiss had realized that the dramatic rise in scientific interest and research in Europe would create a demand for precision instruments—instruments his shop could easily provide. However, neither Zeiss nor his employees possessed the scientific knowledge to design such instruments. Abbe was hired as a consultant to mathematically design lenses of unrivaled excellence. The science of lenscrafting had stalled since the time of Anton van Leeuwenhoek (1632–1723), chiefly due to certain seemingly insurmountable flaws in man-made lenses. Foremost among these was the problem of chromatic aberration, which manifested itself as colored circles around the subject. Scientists were also frustrated with the poor quality of the glass used to make lenses. During the following decade, Abbe worked on new grinding procedures that might correct chromatic aberration; by combining his efforts with Zeiss’s glassmaker, Otto Schott, he eventually succeeded in producing near-flawless scientific lenses of exceptionally high power. These same ten years were profitable ones for Abbe. With the increasing success of the Zeiss Works, Abbe was recognized as a scientist and was given a professorship at Jena University in 1875. Zeiss, who realized that the success of his business was in no small part due to Abbe’s efforts, made the young professor a partner in 1876. Abbe’s work on theoretical optics earned him international notoriety, and he was offered a position at the prestigious University of Berlin (a position he declined in order to continue his research at Zeiss). During their collaboration Abbe and Zeiss produced thousands of scientific optical instruments. Their innovations set important standards for the development of telescopes and photographic equipment. Carl Zeiss died in 1888 leaving the entire Zeiss Works to Abbe. In addition to running the company, Abbe used his own considerable funds to set up the Carl Zeiss Foundation, an organization for the advancement of science and social improvement. See also History of microbiology; Microscope and microscopy AAcne, microbial basis of CNE, MICROBIAL BASIS OF Acne is a condition that affects the hair follicles. A hair follicle consists of a pore the opens to the surface of the skin. The pore leads inward to a cavity that is connected to oil glands. The glands, which are called sebaceous glands, produce oil (sebum) that lubricates the skin and the hair that grows out of the cavity. As the hair grows the oil leaves the cavity and spreads out over the surface of the skin, were it forms a protective coating. However, in conditions such as acne, the oil becomes trapped in the cavities of the hair follicles. This accumulation of oil is irritating and so causes an inflammation. One consequence of the inflammation is an unsightly, scabby appearing crust on the surface of the skin over the inflamed follicles. This surface condition is acne. Acne is associated with the maturation of young adults, particularly boys. Part of the maturation process involves the production or altered expression of hormones. In adolescence certain hormones called androgens are produced. Androgens stimulate the enlargement of the sebaceous glands and the resulting production of more oil, to facilitate the manufacture of more facial hair. In girls, androgen production is greater around the time of menstruation. Acne often appears in young women at the time of their monthly menstrual period. womi_A 5/6/03 1:05 PM Page 1

Acridine orange WORLD OF MICROBIOLOGY AND IMMUNOLOGY 2 • • In this altered hormonal environment, bacteria play a role in the development of acne. The principal bacterial species associated with acne is Proprionibacterium acnes. This microorganism is a normal resident on the skin and inside hair follicles. Normally, the outward flow of oil will wash the bacteria to the surface and be removed when the face is washed. However, in the androgen-altered hair follicles, the cells lining the cavity shed more frequently, stick together, mix with the excess oil that is being produced, and pile up in clumps inside the cavity. The accumulated material is a ready nutrient source for the Proprionibacterium acnes in the cavity. The bacteria grow and multiply rapidly. Two other bacterial species that live and grow on the surface of the skin can be associated with acne. These are Proprionibacterium granulosum and Staphylocccus epidermidis. Their significance is less than Proprionibacterium acnes, however. As the numbers of bacteria increase, the by-products of their metabolic activities cause even more inflammation. Also, the bacteria contain enzymes that can degrade the oil from the oil glands into what are known as free fatty acids. These free fatty acids are very irritating to the skin. Various other bacterial enzymes contribute to inflammation, including proteases and phosphatases. The immune system does react to the abnormal growth of the bacteria by trying to clear the bacteria. Death of bacteria combined with the immune response generates the material known as pus. A hallmark of acne is often the pus that is exuded from the crusty sores on the skin. The altered environment within the hair follicle that facilitates the explosive growth of Proprionibacterium acnes can be stimulated by factors other than the altered hormone production of puberty. The external environment, particularly a warm and moist one, is one factor. The damage caused by bacteria in acne ranges from mild to severe. In a mild case of acne, only a so-called blackheads or whiteheads are evident on the skin. More severe cases are associated with more blackheads, whiteheads and pimples, and also with inflammation. The most severe form, called cystic acne, may produce marked inflammation over the entire upper body, and requires a physician’s attention to reduce the bacterial populations. Reduction in the bacterial number involves slowing down the secretion of the oil from the oil glands and making the follicle pore more open, so that the normal outward flow can occur. Oil production can be slowed in the presence of 12- cis-retinoic acid (Accutane). Use of this medication is reserved for severe cases of acne, as the retinoic acid can have significant adverse side effects. Antibacterial agents can also be useful. For example, many antibacterial creams and face washes contain the compound called benzoyl peroxide, which is very active against Proprionibacterium acnes. Because the bacteria active in acne are normal residents of the skin, there is no “cure” for acne. Rather, the condition is lessened until biochemical or lifestyle changes in the individual lessen or eliminate the conditions that promote bacterial overgrowth. See also Microbial flora of the skin; Skin infections AAcridine orange CRIDINE ORANGE Acridine orange is a fluorescent dye. The compound binds to genetic material and can differentiate between deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). A fluorescent dye such as acridine orange absorbs the energy of incoming light. The energy of the light passes into the dye molecules. This energy cannot be accommodated by the dye forever, and so is released. The released energy is at a different wavelength than was the incoming light, and so is detected as a different color. Acridine orange absorbs the incoming radiation because of its ring structure. The excess energy effectively passes around the ring, being distributed between the various bonds that exist within the ring. However, the energy must be dissipated to preserve the stability of the dye structure. The ring structure also confers a hydrophobic (waterhating) nature to the compound. When applied to a sample in solution, the acridine orange will tend to diffuse spontaneously into the membrane surrounding the microorganisms. Once in the interior of the cell, acridine orange can form a complex with DNA and with RNA. The chemistries of these complexes affect the wavelength of the emitted radiation. In the case of the acridine orange–DNA complex, the emitted radiation is green. In the case of the complex formed with RNA, the emitted light is orange. The different colors allow DNA to be distinguished from RNA. Binding of acridine orange to the nucleic acid occurs in living and dead bacteria and other microorganisms. Thus, the dye is not a means of distinguishing living from dead microbes. Nor does acridine orange discriminate between one species of microbe versus a different species. However, acridine orange has proved very useful as a means of enumerating the total number of microbes in a sample. Knowledge of the total number of bacteria versus the number of living bacteria Facial acne caused by Propionibacterium acne. womi_A 5/6/03 1:05 PM Page 2

WORLD OF MICROBIOLOGY AND IMMUNOLOGY Adenoviruses 3 • • can be very useful in, for example, evaluating the effect of an antibacterial agent on the survival of bacteria. Acridine orange is utilized in the specialized type of light microscopic technique called fluorescence microscopy. In addition, fluorescence of DNA or RNA can allow cells in a sample to be differentiated using the technique of flow cytometry. This sort of information allows detailed analysis of the DNA replication cycle in microorganisms such as yeast. See also Laboratory techniques in microbiology A ActinomycesCTINOMYCES Actinomyces is a genus of bacteria. The bacteria that grouped in this genus share several characteristics. The bacteria are rod-like in shape. Under the light microscope, Actinomyces appear fungus-like. They are thin and joined together to form branching networks. Bacteria of this genus retain the primary stain in the Gram stain reaction, and so are classified as being Gram positive. Actinomycetes are not able to form the dormant form known as a spore. Finally, the bacteria are able to grow in the absence of oxygen. Members of the genus Actinomyces are normal residents of the mouth, throat, and intestinal tract. But they are capable of causing infections both in humans and in cattle if they are able to enter other regions. This can occur as the result of an accident such as a cut or abrasion. An infection known as Actinomycosis is characterized by the formation of an abscess—a process “walling off” the site of infection as the body responds to the infection—and by swelling. Pus can also be present. The pus, which is composed of dead bacteria, is granular, because of the presence of granules of sulfur that are made by the bacteria. The diagnosis of an Actinomyces infection can be challenging, as the symptoms and appearance of the infection is reminiscent of a tumor or of a tuberculosis lesion. A wellestablished infection can produce a great deal of tissue damage. Additionally, the slow growth of the bacteria can make the treatment of infection with antibiotics very difficult, because antibiotics rely on bacterial growth in order to exert their lethal effect. The culturing of Actinomyces in the laboratory is also challenging. The bacteria do not grow on nonselective media, but instead require the use of specialized and nutritionally complex selective media. Furthermore, incubation needs to be in the absence of oxygen. The growth of the bacteria is quite slow. Solid growth medium may need to be incubated for up to 14 days to achieve visible growth. In contrast, a bacterium like Escherichia coli yields visible colonies after overnight growth on a variety of nonselective media. The colonies of Actinomyces are often described as looking like bread crumbs. Currently, identification methods such as polymerase chain reaction (PCR), chromatography to detect unique cell wall constituents, and antibody-based assays do always perform effectively with Actinomyces. See also Anaerobes and anaerobic infections; Microbial flora of the oral cavity, dental caries ACTIVE TRANSPORT • see CELL MEMBRANE TRANSPORT AAdenovirusesDENOVIRUSES Adenoviruses are viruses which have twenty sides. As such they are called icosahedrons. The outer surface, the capsid, is made of particles of a protein. The protein is arranged in groups of six (hexagons) except at the twenty points where the sides meet (each is called an apex), where the particles are in a pentagon arrangement. A so-called penton fibre, which resembles a stick with a ball at the end, protrudes from each apex. Adenoviruses contain deoxyribonucleic acid (DNA) as their genetic material. The DNA encodes 20 to 30 proteins, 15 of which are proteins that form the structure of the virus particle. Similar to other viruses, adenoviruses invade a host cell and use the host genetic machinery to manufacture new virus particles. The new viruses are released from the host cell. Children suffer from adenovirus infections much more so than adults. The viruses of this group infect the membranes that line the respiratory tract, the eyes, the intestines, and the urinary tract. The adenoviruses that infect humans usually cause mild maladies, including respiratory and intestinal illnesses and conjunctivitis (an inflammation of eye membrane, which is also commonly called “pink eye”). A more severe eye malady called keratoconjunctivitis can more widely infect the eye. The eye infections are very contagious and are typically a source of transmission of adenovirus from one person to another. Children can also develop a sore throat, runny nose, cough and flu-like illness. Bronchitis, an inflammation of the membranes lining the air passages in the lungs, can also result from adenovirus infection, as can an inflammation of the stomach called gastroenteritis. Urinary tract infections can cause pain and burning upon urination and blood in the urine. In dogs, adenovirus type 2 causes what is known as kennel cough. But curiously, the virus also protects dogs against hepatitis. In the setting of the laboratory, some of the human strains of adenovirus can transform cells being grown in cell culture. Transformed cells are altered in their regulation of growth, such that the unrestricted growth characteristic of cancers occurs. Adenoviruses have been known since the mid-1950s. They were first isolated from infected tonsils and adenoidal tissue in 1953. Within the next several years they had been obtained from cells involved in respiratory infections. In 1956, the multiple antigenic forms of the virus that had been discovered were classified as adenovirus. Then, in 1962, laboratory studies demonstrated that an adenovirus caused tumors in womi_A 5/6/03 1:06 PM Page 3

Adjuvant WORLD OF MICROBIOLOGY AND IMMUNOLOGY 4 • • rodents. This was the first known human virus capable of inducing tumors in animals. More recently, the basis of the tumor-inducing activity has been unraveled. Genes that are active early in the replication cycle of adenovirus produce proteins that interfere with host proteins that are known as anti-oncogenes. Normally, the anti-oncogen proteins are responsive to cell growth, and so act as a signal to the cell to halt growth. By disrupting the antioncogene proteins, this stop signal is eliminated, resulting in the continued and uncontrolled growth of the cell. A tumor is produced. Thus, adenoviruses have become important as one of the central triggers of cancer development. Such cancers may be a by-product of adenovirus infections. These infections are not by themselves serious. Most tend to appear and run their course within a few weeks. The infections are fairly common. For example, most children will have antibodies to at least four types of adenovirus. Adenovirus gains entry through a break in the skin or are inhaled. The stick-and-ball appearing penton fibers may have a role in the attachment of the virus particle to a protein on the surface of the host epithelial cell. Adenovirus infections have contributed to the spread of bacterial antibiotic resistance because of the overuse of antibiotics. The flu-like symptoms of some adenovirus infections can lead to the prescribing of antibiotics as a treatment. However, antibiotics are ineffective against viruses. But the circulating antibiotic can provide selective pressure on the development of resistant in bacterial populations. See also Bacterial adaptation; Transformation AAdjuvantDJUVANT An adjuvant is any substance that enhances the response of the immune system to the foreign material termed an antigen. The particular antigen is also referred to as an immunogen. An adjuvant can also be any substance that enhances the effect of a drug on the body. When antigen is injected into an organism being used to raise antibodies the effect is to stimulate a greater and more prolonged production of antibody than would otherwise occur if the antigen were injected alone. Indeed, adjuvants are very useful if a substance itself is not strongly recognized by the immune system. An example of such a weak immunogen is the capsule exopolysaccharide of a variety of bacteria. Adjuvants exert their effect in several different ways. Firstly, some adjuvants retain the antigen and so “present” the antigen to the immune system over a prolonged period of time. The immune response does not occur all at once, but rather is Negative stain electron micrograph of an Adenovirus. womi_A 5/6/03 1:06 PM Page 4