Bacteriology

Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit the air, soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition

thumb|upright=1.35|alt=image of prokaryotic cell|Diagram of a prokaryotic cell, a Bacteria|bacterium with a flagellum

Hungarian physician, early pioneer of antiseptic procedures (1818–1865)

right|thumb|upright=1.2|Scanning electron micrograph of Escherichia coli, a common human pathogen and research organism. Bacteriology is the branch and specialty of biology that studies the morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to them. This subdivision of microbiology involves the identification, classification, and characterization of bacterial species. Because of the similarity of thinking and working with microorganisms other than bacteria, such as protozoa, fungi, and non-microorganism viruses, there has been a tendency for the fi

species of bacterium

microbiological method for identification; method of staining used to differentiate bacterial species into two large groups (gram-positive and gram-negative)

group of bacteria that do not retain the Gram stain used in bacterial differentiation

thumb|right|A bottle of Yakult, a probiotic drink containing [[Lactobacillus paracasei]] Probiotics are live microorganisms in that are intended to support or improve the health and wellbeing of a host organism. They are commonly used in both humans and animals. Although the term refers to the microorganisms themselves, probiotics can be consumed through a range of products including yogurt, cheese, certain fermented foods (such as nattō), as well as capsules containing a single strain or a defined mixture of strains.

bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their cell wall

community of microorganisms in the digestive tracts of humans

thumb|An Endospore staining|endospore stain of the cell [[Bacillus subtilis showing endospores as green and the vegetative cell as red]] thumb|Phase-bright endospores of Paenibacillus alvei imaged with phase-contrast microscopy 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 (endo means 'within'), but it is not a true spore (i.e., not an offspring). It is a stripped-down, dormant form to which the bacterium can reduce itself. Endospore formation is usually trigger

thumb|right|300px|Staphylococcus aureus biofilm on an indwelling [[catheter]]

The nucleoid (meaning nucleus-like) is an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material. The chromosome of a typical prokaryote is circular, and its length is very large compared to the cell dimensions, so it needs to be compacted in order to fit. In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane. Instead, the nucleoid forms by condensation and functional arrangement with the help of chromosomal architectural proteins and RNA molecules as well as DNA supercoiling. Genome length varies widely (ge

transfer of genetic information to a bacterium from a bacteriophage, or between bacterial or yeast cells, mediated by a phage vector

natural genetic exchange of bacteria

nutritional chemicals that induce the growth of microorganisms

microorganisms in or on human tissues and biofluids

process in which single-celled organisms monitor their population density by detecting the concentration of small, diffusible signal molecules produced by the cells themselves.

microbiological method for identification

polysaccharide layer that lies outside the cell envelope in many bacteria

process of virus reproduction in which the bacteriophage DNA is integrated into the host bacterium's genome

thumb|Transmission electron microscope image of a cross section through a soybean (Glycine max) [[root nodule. The nitrogen fixing bacteria, and fungi Bradyrhizobium japonicum, infects the roots and establishes a symbiosis. This high magnification image shows part of a cell with single bacteroid (bacterium-like cell or modified bacterial cell) within their symbiosomes. In this image, you can also see endoplasmic reticulum, Golgi apparatus and cell wall.]]

The periplasm is a concentrated gel-like matrix in the space between the inner cytoplasmic membrane and the bacterial outer membrane called the periplasmic space in Gram-negative (more accurately "diderm") bacteria. Using cryo-electron microscopy it has been found that a much smaller periplasmic space is also present in Gram-positive bacteria (more accurately "monoderm"), between cell wall and the plasma membrane. The periplasm may constitute up to 40% of the total cell volume of gram-negative bacteria, but is a much smaller percentage in gram-positive bacteria.

community of microorganisms in the vagina

chemical compound

collective bacteria and other microorganisms in a host

chemolithotrophic organism(s)

species of bacterium

225px|thumb|Formation of a prophageA prophage is a bacteriophage (often shortened to "phage") genome that is integrated into the circular bacterial chromosome or exists as an extrachromosomal plasmid within the bacterial cell. Integration of prophages into the bacterial host is the characteristic step of the lysogenic cycle of temperate phages. Prophages remain latent in the genome through multiple cell divisions until activation by an external factor, such as UV light, leading to production of new phage particles that will lyse the cell and spread. As ubiquitous mobile genetic elements, proph

thumb|upright=2| Diverse microbial communities of characteristic microbiota are part of plant microbiomes, and are found on the outside surfaces and in the internal tissues of the host plant, as well as in the surrounding soil.

thumb|300px|Lake Erie in October 2011, during an intense cyanobacteria bloom

specialized anatomy and physiology of bacteria

growth of bacterial colonies

thumb|220px|A collage of different bacteria viewed under a microscope. A bacteriologist is a microbiologist, or similarly trained professional, in bacteriology— a subdivision of microbiology that studies bacteria, typically pathogenic ones. Bacteriologists are interested in studying and learning about bacteria, as well as using their skills in clinical settings. This includes investigating properties of bacteria such as morphology, ecology, genetics and biochemistry, phylogenetics, genomics and many other areas related to bacteria like disease diagnostic testing. Alongside human and animal hea

ability of some bacteria to alter their shape or size in response to environmental conditions

Phycobilisomes are light-harvesting antennae that transmit the energy of harvested photons to photosystem II and photosystem I in cyanobacteria and in the chloroplasts of red algae and glaucophytes. They were lost during the evolution of the chloroplasts of green algae and plants.

Integrons are genetic mechanisms that allow bacteria to adapt and evolve rapidly through the stockpiling and expression of new genes. These genes are embedded in a specific genetic structure called gene cassette (a term that is lately changing to integron cassette) that generally carries one promoterless open reading frame (ORF) together with a recombination site (attC). Integron cassettes are incorporated to the attI site of the integron platform by site-specific recombination reactions mediated by the integrase.

study of the ecology of microorganisms

former research initiative

bacterial appendage

community of microorganisms of the skin

microbiological and biochemical method for identification

class of adhesion proteins

The F-plasmid (first named F by one of its discoverers Esther Lederberg；also called the sex factor in E. coli，the F sex factor, the fertility factor, or simply the F factor) allows genes to be transferred from one bacterium carrying the factor to another bacterium lacking the factor by conjugation. The F factor was the first plasmid to be discovered. Unlike other plasmids, F factor is constitutive for transfer proteins due to a mutation in the gene finO. The F plasmid belongs to F-like plasmids, a class of conjugative plasmids that control sexual functions of bacteria with a fertility inhibiti

species of bacterium

In biology, axenic (, ) describes the state of a culture in which only a single species, variety, or strain of organism is present and entirely free of all other contaminating organisms. The earliest axenic cultures were of bacteria or unicellular eukaryotes, but axenic cultures of many multicellular organisms are also possible. Axenic culture is an important tool for the study of symbiotic and parasitic organisms in a controlled environment.

certain bacteria that do not cause tuberculosis

gluey polymers secreted by microorganisms to form biofilms

Manual for identifying prokaryotic organisms

Acidogenesis is the second stage in the four stages of anaerobic digestion: Hydrolysis: A chemical reaction where particulates are solubilized and large polymers converted into simpler monomers; Acidogenesis: A biological reaction where simple monomers are converted into volatile fatty acids; Acetogenesis: A biological reaction where volatile fatty acids are converted into acetic acid, carbon dioxide, and hydrogen Methanogenesis: A biological reaction where acetates are converted into methane and carbon dioxide, while hydrogen is consumed. Anaerobic digestion is a complex biochemical proce

classification for certain species of the genus Streptococcus

Synbiotics refer to food ingredients or dietary supplements combining probiotics and prebiotics in a form of synergism, hence synbiotics. Synbiotics may be complementary synbiotics, where each component is independently chosen for its potential effect on host health, or synergistic synbiotics, where the prebiotic component is chosen to support the activity of the chosen probiotic. Research is evaluating if synbiotics can be optimized, (known as 'optibiotics') which are purported to enhance the growth and health benefits of existing probiotics.

method for isolation of bacterial strains

Pseudomonadati is a prokaryotic kingdom containing approximately one-third of prokaryote species, mostly gram-negative bacteria and their relatives. It is the closest relative of an even larger kingdom of Bacteria, the Bacillati, which are mostly gram-positive bacteria.

Reuterin (3-hydroxypropionaldehyde) is the organic compound with the formula HOCH2CH2CHO. It is a bifunctional molecule, containing both a hydroxy and aldehyde functional groups.

Psychobiotics is a term used in preliminary research to refer to live bacteria that, when ingested in appropriate amounts, might confer a mental health benefit by affecting microbiota of the host organism. Whether bacteria might play a role in the gut-brain axis is under research. A 2020 literature review suggests that the consumption of psychobiotics could be considered as a viable option to restore mental health although lacking randomized controlled trials on clear mental health outcomes in humans.

Gracilicutes (Latin: gracilis, slender, and cutis, skin, referring to the cell wall) is a clade in bacterial phylogeny.

type of chromosome

Postbiotics are preparations of dead microorganisms and/or their components that are believed to confer a health benefit on the host. Most such preparations are derived from bacteria believed to be beneficial (so-called probiotics), with most purported benefits having to do with the digestive tract.

Medical test to detect & identify bacteria or fungi in lung airways