A bacteriophage, also known informally as a phage, is a virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν, meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm.
A biofilm is a syntrophic community of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric combination of extracellular polysaccharides, proteins, lipids and DNA. Because they have a three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes".
In biology, quorum sensing or quorum signaling (QS) is the process of cell-to-cell communication that allows bacteria to detect and respond to cell population density by gene regulation, typically as a means of acclimating to environmental disadvantages.
A prophage is a bacteriophage 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, prophages play important roles in bacterial genetics and evolution, such as in the acquisition of virulence factors.
Phage therapy, viral phage therapy, or phagotherapy is the therapeutic use of bacteriophages for the treatment of pathogenic bacterial infections. This therapeutic approach emerged at the beginning of the 20th century but was progressively replaced by the use of antibiotics in most parts of the world after the Second World War. Bacteriophages, known as phages, are a form of virus that attach to bacterial cells and inject their genome into the cell. The bacteria's production of the viral genome interferes with its ability to function, halting the bacterial infection. The bacterial cell causing the infection is unable to reproduce and instead produces additional phages. Phages are very selective in the strains of bacteria they are effective against.
A slime layer in bacteria is an easily removable, unorganized layer of extracellular material that surrounds bacteria cells. Specifically, this consists mostly of exopolysaccharides, glycoproteins, and glycolipids. Therefore, the slime layer is considered as a subset of glycocalyx.
Pseudomonas aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, P. aeruginosa is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes. P. aeruginosa is able to selectively inhibit various antibiotics from penetrating its outer membrane - and has high resistance to several antibiotics. According to the World Health Organization P. aeruginosa poses one of the greatest threats to humans in terms of antibiotic resistance.
Medical microbiology, the large subset of microbiology that is applied to medicine, is a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion.
Extracellular polymeric substances (EPSs) are natural polymers of high molecular weight secreted by microorganisms into their environment. EPSs establish the functional and structural integrity of biofilms, and are considered the fundamental component that determines the physicochemical properties of a biofilm. EPS in the matrix of biofilms provides compositional support and protection of microbial communities from the harsh environments. Components of EPS can be of different classes of polysaccharides, lipids, nucleic acids, proteins, lipopolysaccharides, and minerals.
In biology, an autoinducer is a signaling molecule that enables detection and response to changes in the population density of bacterial cells. Synthesized when a bacterium reproduces, autoinducers pass outside the bacterium and into the surrounding medium. They are a key component of the phenomenon of quorum sensing: as the density of quorum-sensing bacterial cells increases, so does the concentration of the autoinducer. A bacterium’s detection of an autoinducer above some minimum threshold triggers altered gene expression.
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.
Urs Jenal is a Swiss Microbiologist and Professor at the Biozentrum University of Basel, Switzerland.
Elizabeth "Liz" Harry is Professor of Biology and Director of the ithree institute at the University of Technology, Sydney, Australia (UTS).
Everett Peter Greenberg is an American microbiologist. He is the inaugural Eugene and Martha Nester Professor of Microbiology at the Department of Microbiology of the University of Washington School of Medicine. He is best known for his research on quorum sensing, and has received multiple awards for his work.
Twitching motility is a form of crawling bacterial motility used to move over surfaces. Twitching is mediated by the activity of hair-like filaments called type IV pili which extend from the cell's exterior, bind to surrounding solid substrates, and retract, pulling the cell forwards in a manner similar to the action of a grappling hook. The name twitching motility is derived from the characteristic jerky and irregular motions of individual cells when viewed under the microscope. It has been observed in many bacterial species, but is most well studied in Pseudomonas aeruginosa, Neisseria gonorrhoeae and Myxococcus xanthus. Active movement mediated by the twitching system has been shown to be an important component of the pathogenic mechanisms of several species.
Katharina Ribbeck is a German-American biologist. She is the Andrew (1956) and Erna Viterbi Professor of Biological Engineering at the Massachusetts Institute of Technology. She is known as one of the first researchers to study how mucus impacts microbial behavior. Ribbeck investigates both the function of mucus as a barrier to pathogens such as fungi, bacteria, and viruses and how mucus can be leveraged for therapeutic purposes. She has also studied changes that cervical mucus undergoes before birth, which may lead to a novel diagnostic for the risk of preterm birth.
Karine Gibbs is a Jamaican American microbiologist and immunologist and an associate professor in the Department of Plant and Microbial Biology at the University of California, Berkeley. Gibbs’ research merges the fields of sociomicrobiology and bacterial cell biology to explore how the bacterial pathogen Proteus mirabilis, a common gut bacterium which can become pathogenic and cause urinary tract infections, identifies self versus non-self. In 2013, Gibbs and her team were the first to sequence the genome of P. mirabilis BB2000, the model organism for studying self-recognition. In graduate school at Stanford University, Gibbs helped to pioneer the design of a novel tool that allowed for visualization of the movement of bacterial membrane proteins in real time. In 2020, Gibbs was recognized by Cell Press as one of the top 100 Inspiring Black Scientists in America.
Jessica A. Scoffield is an American microbiologist and an assistant professor in the Department of Microbiology at the University of Alabama at Birmingham School of Medicine. Scoffield studies the mechanisms by which oral commensal bacteria interfere with pathogenic bacterial growth in order to inform the development of active therapeutic tools to prevent drug resistant pathogen infection. In 2019, Scoffield became the inaugural recipient of the American Association for Dental Research Procter and Gamble Underrepresented Faculty Research Fellowship.
Alain Ange-Marie Filloux is a French/British microbiologist who is a Professor of Molecular Microbiology at Imperial College London. His research looks at the chronic infection of Pseudomonas aeruginosa, a Gram-negative bacterium that causes nosocomial infections in people who are immunocompromised and a deadly threat for cystic fibrosis patients.
Ian Charles OBE is Director of the Quadram Institute in Norwich, UK. The Institute combines Quadram Institute Bioscience and the endoscopy centre of the Norfolk and Norwich University Hospitals NHS Foundation Trust. It is closely allied with the University of East Anglia and the BBSRC. Charles' field of research is infectious diseases and the microbiome and its impact on health and well-being.
“Professor Cynthia Whitchurch FAA”, Australian Academy of Science, 27 May 2019