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 which allows bacteria the ability to detect and respond to cell population density by gene regulation, typically as a means of acclimating to environmental disadvantages.
Candida albicans is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usually a commensal organism, but it can become pathogenic in immunocompromised individuals under a variety of conditions. It is one of the few species of the genus Candida that cause the human infection candidiasis, which results from an overgrowth of the fungus. Candidiasis is, for example, often observed in HIV-infected patients. C. albicans is the most common fungal species isolated from biofilms either formed on (permanent) implanted medical devices or on human tissue. C. albicans, C. tropicalis, C. parapsilosis, and C. glabrata are together responsible for 50–90% of all cases of candidiasis in humans. A mortality rate of 40% has been reported for patients with systemic candidiasis due to C. albicans. By one estimate, invasive candidiasis contracted in a hospital causes 2,800 to 11,200 deaths yearly in the US. Nevertheless, these numbers may not truly reflect the true extent of damage this organism causes, given new studies indicating that C. albicans can cross the blood–brain barrier in mice.
Lactoferrin (LF), also known as lactotransferrin (LTF), is a multifunctional protein of the transferrin family. Lactoferrin is a globular glycoprotein with a molecular mass of about 80 kDa that is widely represented in various secretory fluids, such as milk, saliva, tears, and nasal secretions. Lactoferrin is also present in secondary granules of PMNs and is secreted by some acinar cells. Lactoferrin can be purified from milk or produced recombinantly. Human colostrum has the highest concentration, followed by human milk, then cow milk (150 mg/L).
Phenotypic switching is switching between multiple cellular morphologies. David R. Soll described two such systems: the first high frequency switching system between several morphological stages and a second high frequency switching system between opaque and white cells. The latter is an epigenetic switching system
Candida parapsilosis is a fungal species of yeast that has become a significant cause of sepsis and of wound and tissue infections in immunocompromised people. Unlike Candida albicans and Candida tropicalis, C. parapsilosis is not an obligate human pathogen, having been isolated from nonhuman sources such as domestic animals, insects and soil. C. parapsilosis is also a normal human commensal and it is one of the fungi most frequently isolated from human hands. There are several risk factors that can contribute to C. parapsilosis colonization. Immunocompromised individuals and surgical patients, particularly those undergoing surgery of the gastrointestinal tract, are at high risk for infection with C. parapsilosis. There is currently no consensus on the treatment of invasive candidiasis caused by C. parapsilosis, although the therapeutic approach typically includes the removal of foreign bodies such as implanted prostheses and the administration of systemic antifungal therapy. Amphotericin B and Fluconazole are often used in the treatment of C. parapsilosis infection.
A chlamydospore is the thick-walled large resting spore of several kinds of fungi, including Ascomycota such as Candida, Basidiomycota such as Panus, and various Mortierellales species. It is the life-stage which survives in unfavourable conditions, such as dry or hot seasons. Fusarium oxysporum which causes the plant disease Fusarium wilt is one which forms chlamydospores in response to stresses like nutrient depletion. Mycelia of the pathogen can survive in this manner and germinate in favorable conditions.
Dimorphic fungi are fungi that can exist in the form of both mold and yeast. This is usually brought about by change in temperature and the fungi are also described as thermally dimorphic fungi. An example is Talaromyces marneffei, a human pathogen that grows as a mold at room temperature, and as a yeast at human body temperature.
Oral ecology is the microbial ecology of the microorganisms found in mouths. Oral ecology, like all forms of ecology, involves the study of the living things found in oral cavities as well as their interactions with each other and with their environment. Oral ecology is frequently investigated from the perspective of oral disease prevention, often focusing on conditions such as dental caries, candidiasis ("thrush"), gingivitis, periodontal disease, and others. However, many of the interactions between the microbiota and oral environment protect from disease and support a healthy oral cavity. Interactions between microbes and their environment can result in the stabilization or destabilization of the oral microbiome, with destabilization believed to result in disease states. Destabilization of the microbiome can be influenced by several factors, including diet changes, drugs or immune system disorders.
Persister cells are subpopulations of cells that resist treatment, and become antimicrobial tolerant by changing to a state of dormancy or quiescence. Persister cells in their dormancy do not divide. The tolerance shown in persister cells differs from antimicrobial resistance in that the tolerance is not inherited and is reversible. When treatment has stopped the state of dormancy can be reversed and the cells can reactivate and multiply. Most persister cells are bacterial, and there are also fungal persister cells, yeast persister cells, and cancer persister cells that show tolerance for cancer drugs.
Lorena Beese is a James B. Duke Professor of Biochemistry and Duke Cancer Institute Member. Her research involves structural mechanisms underlying DNA replication and repair, neurodegenerative diseases, cancer, and microbial pathogenesis; X-ray crystallography and cryo-electron microscopy; structure-based drug design; protein-protein and protein-nucleic acid interactions, enzyme mechanisms, chemical biology, protein structure and function.
Mycobiota are a group of all the fungi present in a particular geographic region or habitat type. An analogous term for Mycobiota is funga.
Fungal adhesins are proteins located on the surface of fungal cells, specifically found on the outside of the cell wall. They allow fungi to colonize various substrates and to bind to host tissues. Adhesion to tissue is an obligatory first step in pathogenesis by many yeasts. Adhesins also have other functions, such as mating and biofilm formation.
Neil Andrew Robert Gow is a professor of Microbiology and deputy Vice Chancellor at the University of Exeter. Previously he served at the University of Aberdeen for 38 years and retains an honorary chair there.
Candida tropicalis is a species of yeast in the genus Candida. It is a common pathogen in neutropenic hosts, in whom it may spread through the bloodstream to peripheral organs. For invasive disease, treatments include amphotericin B, echinocandins, or extended-spectrum triazole antifungals.
Kaustuv Sanyal is an Indian molecular biologist, mycologist and a professor at the Molecular Biology and Genetics Unit of the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR). He is known for his molecular and genetic studies of pathogenic yeasts such as Candida and Cryptococcus). An alumnus of Bidhan Chandra Krishi Viswavidyalaya and Madurai Kamaraj University from where he earned a BSc in agriculture and MSc in biotechnology respectively, Sanyal did his doctoral studies at Bose Institute to secure a PhD in Yeast genetics. He moved to the University of California, Santa Barbara, USA to work in the laboratory of John Carbon on the discovery of centromeres in Candida albicans. He joined JNCASR in 2005. He is a member of the Faculty of 1000 in the disciplines of Microbial Evolution and Genomics and has delivered invited speeches which include the Gordon Research Conference, EMBO conferences on comparative genomics and kinetochores. The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards, for his contributions to biosciences, in 2012. He has also been awarded with the prestigious Tata Innovation Fellowship in 2017. The National Academy of Sciences, India elected him as a fellow in 2014. He is also an elected fellow of Indian Academy of Sciences (2017), and the Indian National Science Academy (2018). In 2019, he has been elected to Fellowship in the American Academy of Microbiology (AAM), the honorific leadership group within the American Society for Microbiology.
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.
Alexander "Sandy" D. Johnson is an American biochemist and Professor and Vice Chair of the Department of Microbiology and Immunology at the University of California, San Francisco. He is a member of the U.S. National Academy of Sciences.
Carol Kumamoto is an American microbiologist who is Professor of Molecular Biology & Microbiology at Tufts University. She investigates the filamentous growth of Candida albicans, a fungal pathogen that causes several diseases. She is also interested in how C. albicans interacts with its host during colonisation and invasive diseases. She is a Fellow of the American Association for the Advancement of Science and the American Academy of Microbiology.
Frank C. Odds was an English mycologist. He studied Candida albicans, establishing how modern researchers study fungal pathogens and the diseases they cause.
