Bacillus is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum Bacillota, with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural Bacilli is the name of the class of bacteria to which this genus belongs. Bacillus species can be either obligate aerobes which are dependent on oxygen, or facultative anaerobes which can survive in the absence of oxygen. Cultured Bacillus species test positive for the enzyme catalase if oxygen has been used or is present.
Heinrich Hermann Robert Koch was a German physician and microbiologist. As the discoverer of the specific causative agents of deadly infectious diseases including tuberculosis, cholera and anthrax, he is regarded as one of the main founders of modern bacteriology. As such he is popularly nicknamed the father of microbiology, and as the father of medical bacteriology. His discovery of the anthrax bacterium in 1876 is considered as the birth of modern bacteriology. Koch used his discoveries to establish that germs "could cause a specific disease" and directly provided proofs for the germ theory of diseases, therefore creating the scientific basis of public health, saving millions of lives. For his life's work Koch is seen as one of the founders of modern medicine.
Bacillus cereus is a Gram-positive rod-shaped bacterium commonly found in soil, food, and marine sponges. The specific name, cereus, meaning "waxy" in Latin, refers to the appearance of colonies grown on blood agar. Some strains are harmful to humans and cause foodborne illness due to their spore-forming nature, while other strains can be beneficial as probiotics for animals, and even exhibit mutualism with certain plants. B. cereus bacteria may be aerobes or facultative anaerobes, and like other members of the genus Bacillus, can produce protective endospores. They have a wide range of virulence factors, including phospholipase C, cereulide, sphingomyelinase, metalloproteases, and cytotoxin K, many of which are regulated via quorum sensing. B. cereus strains exhibit flagellar motility.
Anthrax is an infection caused by the bacterium Bacillus anthracis. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one day and more than two months after the infection is contracted. The skin form presents with a small blister with surrounding swelling that often turns into a painless ulcer with a black center. The inhalation form presents with fever, chest pain, and shortness of breath. The intestinal form presents with diarrhea, abdominal pains, nausea, and vomiting.
An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. The name "endospore" is suggestive of a spore or seed-like form, but it is not a true spore. It is a stripped-down, dormant form to which the bacterium can reduce itself. Endospore formation is usually triggered by a lack of nutrients, and usually occurs in gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries. There are many reports of spores remaining viable over 10,000 years, and revival of spores millions of years old has been claimed. There is one report of viable spores of Bacillus marismortui in salt crystals approximately 25 million years old. When the environment becomes more favorable, the endospore can reactivate itself into a vegetative state. Most types of bacteria cannot change to the endospore form. Examples of bacterial species that can form endospores include Bacillus cereus, Bacillus anthracis, Bacillus thuringiensis, Clostridium botulinum, and Clostridium tetani. Endospore formation is not found among Archaea.
Koch's postulates are four criteria designed to establish a causal relationship between a microbe and a disease. The postulates were formulated by Robert Koch and Friedrich Loeffler in 1884, based on earlier concepts described by Jakob Henle, and the statements were refined and published by Koch in 1890. Koch applied the postulates to describe the etiology of cholera and tuberculosis, both of which are now ascribed to bacteria. The postulates have been controversially generalized to other diseases. More modern concepts in microbial pathogenesis cannot be examined using Koch's postulates, including viruses and asymptomatic carriers. They have largely been supplanted by other criteria such as the Bradford Hill criteria for infectious disease causality in modern public health and the Molecular Koch's postulates for microbial pathogenesis.
Stanley "Stan" Falkow was an American microbiologist and a professor of microbiology at Georgetown University, University of Washington, and Stanford University School of Medicine. Falkow is known as the father of the field of molecular microbial pathogenesis. He formulated molecular Koch's postulates, which have guided the study of the microbial determinants of infectious diseases since the late 1980s. Falkow spent over 50 years uncovering molecular mechanisms of how bacteria cause disease and how to disarm them. Falkow also was one of the first scientists to investigate antimicrobial resistance, and presented his research extensively to scientific, government, and lay audiences explaining the spread of resistance from one organism to another, now known as horizontal gene transfer, and the implications of this phenomenon on our ability to combat infections in the future.
The Ames strain is one of 89 known strains of the anthrax bacterium. It was isolated from a diseased 14-month-old Beefmaster heifer that died in Sarita, Texas in 1981. The strain was isolated at the Texas Veterinary Medical Diagnostic Laboratory and a sample was sent to the United States Army Medical Research Institute of Infectious Diseases (USAMRIID). Researchers at USAMRIID mistakenly believed the strain came from Ames, Iowa because the return address on the package was the USDA's National Veterinary Services Laboratories in Ames and mislabeled the specimen.
Bacillus megaterium is a rod-like, Gram-positive, mainly aerobic, spore forming bacterium found in widely diverse habitats. It has a cell length up to 100 μm and a diameter of 0.1 μm, which is quite large for bacteria. The cells often occur in pairs and chains, where the cells are joined by polysaccharides on the cell walls.
Claire M. Fraser is an American genome scientist and microbiologist who has worked in microbial genomics and genome medicine. Her research has contributed to the understanding of the diversity and evolution of microbial life. Fraser is the director of the Institute for Genome Sciences at the University of Maryland School of Medicine in Baltimore, MD, where she holds the Dean's Endowed Professorship in the School of Medicine. She has joint faculty appointments at the University of Maryland School of Medicine in the Departments of Medicine and Microbiology/Immunology. In 2019, she began serving a one-year term as President-Elect for the American Association for the Advancement of Science (AAAS), which will be followed by a one-year term as AAAS president starting in February 2020 and a one-year term as chair of the Board of Directors in February 2021.
Bacillus anthracis is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus Bacillus. Its infection is a type of zoonosis, as it is transmitted from animals to humans. It was discovered by a German physician Robert Koch in 1876, and became the first bacterium to be experimentally shown as a pathogen. The discovery was also the first scientific evidence for the germ theory of diseases.
Roberto Kolter is Professor of Microbiology, Emeritus at Harvard Medical School, an author, and past president of the American Society for Microbiology. Kolter has been a professor at Harvard Medical School since 1983 and was Co-director of Harvard's Microbial Sciences Initiative from 2003-2018. During the 35-year term of the Kolter laboratory from 1983 to 2018, more than 130 graduate student and postdoctoral trainees explored an eclectic mix of topics gravitating around the study of microbes. Kolter is a fellow of the American Association for the Advancement of Science and of the American Academy of Microbiology.
Nikolay Fyodorovich Gamaleya was a Russian and Soviet physician and scientist who played a pioneering role in microbiology and vaccine research.
In bacteriology, a taxon in disguise is a species, genus or higher unit of biological classification whose evolutionary history reveals has evolved from another unit of a similar or lower rank, making the parent unit paraphyletic. That happens when rapid evolution makes a new species appear so radically different from the ancestral group that it is not (initially) recognised as belonging to the parent phylogenetic group, which is left as an evolutionary grade.
Bacillus atrophaeus is a species of black-pigmented bacteria. Its type strain is NRRL NRS-213. B. atrophaeus strains have been used extensively in biomedicine as indicator strains for heat- and chemical-based decontamination regimens. Most of the strains in use are derivatives of a lineage of B. atrophaeus that originated at Camp Detrick in the 1950s, where many modern biocontainment procedures were developed.
Bacillus cereus biovar anthracis is a variant of the Bacillus cereus bacterium that has acquired plasmids similar to those of Bacillus anthracis. As a result, it is capable of causing anthrax. In 2016, it was added to the CDC's list of select agents and toxins.
In microbiology, colonial morphology refers to the visual appearance of bacterial or fungal colonies on an agar plate. Examining colonial morphology is the first step in the identification of an unknown microbe. The systematic assessment of the colonies' appearance, focusing on aspects like size, shape, colour, opacity, and consistency, provides clues to the identity of the organism, allowing microbiologists to select appropriate tests to provide a definitive identification.
Eric P. Skaar is an American microbiologist, the Ernest W. Goodpasture Professor of Pathology, Microbiology and Immunology at Vanderbilt University Medical Center, and a University Distinguished Professor at Vanderbilt University.
Walter James Nungester was an American bacteriologist and immunologist. He was the president of the American Society for Microbiology in 1951.
Dennis Wallace Watson was a Canadian-American professor of microbiology. He was the president of the American Society for Microbiology (ASM) in 1969.
