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Piet Borst CBE (born 5 July 1934, in Amsterdam) is emeritus professor of clinical biochemistry and molecular biology at the University of Amsterdam (UVA), and until 1999 director of research and chairman of the board of directors of the Netherlands Cancer Institute and the Antoni van Leeuwenhoekziekenhuis (NKI-AVL). He continued to work at the NKI-AVL as a staff member and group leader until 2016.
Piet Borst studied medicine in Amsterdam from 1952 to 1958 and completed his internships in 1961-1962. He received his PhD for an investigation of tumor mitochondria (Supervisor Edward Slater).
He then moved to New York City, where he worked with fellow post-doc Charles Weissmann on replication of bacteriophages in the lab of Nobel laureate Severo Ochoa at the New York University School of Medicine. In 1965, he became professor of Biochemistry at the University of Amsterdam and head of the section for Medical Enzymology and Molecular Biology of the Biochemistry Department. From 1972 to 1980 Borst was also part-time Director of the Institute of Animal Physiology of the University of Amsterdam where he set up the first Unit for Molecular Biology on the Biology Campus.
In 1983 Borst moved to the Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital where he became director of research and in 1987 also chairman. He retained an honorary professorship at the University of Amsterdam. After his mandatory retirement in 1999, Borst became a staff member and continued running his lab, studying mechanisms of chemotherapy resistance in cancer cells, the physiological functions of drug transporters and the biosynthesis and function of DNA Base J, a new base in DNA that had been discovered in trypanosomes by his research group.
Borst contributed to discussions about science and science policy in the Netherlands: In the seventies he was spokesman for science in the rather virulent discussions on recombinant-DNA experiments; as a director of the cancer institute he regularly reported on advances in cancer research/treatment in the press and on radio/TV; he was a member of the Innovation Platform, a small thinktank of the Dutch prime-minister; and for 23 years he wrote a monthly column in the prime intellectual daily, the NRC Handelsblad.
His doctoral students include Jan Hoeijmakers.
Trypanosoma is a genus of kinetoplastids, a monophyletic group of unicellular parasitic flagellate protozoa. Trypanosoma is part of the phylum Sarcomastigophora. The name is derived from the Greek trypano- (borer) and soma (body) because of their corkscrew-like motion. Most trypanosomes are heteroxenous and most are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. Trypanosoma equiperdum is spread between horses and other equine species by sexual contact. They are generally found in the intestine of their invertebrate host, but normally occupy the bloodstream or an intracellular environment in the vertebrate host.
Trypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extracellular and inhabits the blood plasma and body fluids. It causes deadly vector-borne diseases: African trypanosomiasis or sleeping sickness in humans, and animal trypanosomiasis or nagana in cattle and horses. It is a species complex grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense. The first is a parasite of non-human mammals and causes nagana, while the latter two are zoonotic infecting both humans and animals and cause African trypanosomiasis.
Τrypanosoma equiperdum is a species of kinetoplastid parasites that causes Dourine or covering sickness in horses and other animals in the family equidae. T. equiperdum is the only known trypanosome that is not spread by an insect vector. There has been substantial controversy surrounding whether T. equiperdum should be considered a unique species, or a strain of T. evansi or T. brucei. T. equiperdum is unique in that its kinetoplast, the network of connected rings that make up its mitochondrial DNA, consists of thousands of "minicircles" that are identical in sequence.
Antigenic variation or antigenic alteration refers to the mechanism by which an infectious agent such as a protozoan, bacterium or virus alters the proteins or carbohydrates on its surface and thus avoids a host immune response, making it one of the mechanisms of antigenic escape. It is related to phase variation. Antigenic variation not only enables the pathogen to avoid the immune response in its current host, but also allows re-infection of previously infected hosts. Immunity to re-infection is based on recognition of the antigens carried by the pathogen, which are "remembered" by the acquired immune response. If the pathogen's dominant antigen can be altered, the pathogen can then evade the host's acquired immune system. Antigenic variation can occur by altering a variety of surface molecules including proteins and carbohydrates. Antigenic variation can result from gene conversion, site-specific DNA inversions, hypermutation, or recombination of sequence cassettes. The result is that even a clonal population of pathogens expresses a heterogeneous phenotype. Many of the proteins known to show antigenic or phase variation are related to virulence.
N-myc proto-oncogene protein also known as N-Myc or basic helix-loop-helix protein 37 (bHLHe37), is a protein that in humans is encoded by the MYCN gene.
The alternative oxidase (AOX) is an enzyme that forms part of the electron transport chain in mitochondria of different organisms. Proteins homologous to the mitochondrial oxidase and the related plastid terminal oxidase have also been identified in bacterial genomes.
Platelet-derived growth factor subunit A is a protein that in humans is encoded by the PDGFA gene.
Transferrin receptor 2 (TfR2) is a protein that in humans is encoded by the TFR2 gene. This protein is involved in the uptake of transferrin-bound iron into cells by endocytosis, although its role is minor compared to transferrin receptor 1.
Melanotransferrin is a protein that in humans is encoded by the MFI2 gene. MFI2 has also recently been designated CD228.
Canalicular multispecific organic anion transporter 2 is a protein that in humans is encoded by the ABCC3 gene.
Ceramide glucosyltransferase is an enzyme that in humans is encoded by the UGCG gene.
Haptoglobin-related protein is a protein that in humans is encoded by the HPR gene. The HPR gene affects hereditary immunity to a non-pathogenic species of African trypanosomes.
Rh family, C glycoprotein, also known as RHCG, is a protein that in humans is encoded by the RHCG gene.
Cadherin-17 is a protein that in humans is encoded by the CDH17 gene.
T-cell surface glycoprotein CD3 delta chain is a protein that in humans is encoded by the CD3D gene.
In molecular biology mir-451 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms.
Wendy Gibson is Professor of Protozoology at University of Bristol, specialising in trypanosomes and molecular parasitology.
β-D-Glucopyranosyloxymethyluracil or base J is a hypermodified nucleobase found in the DNA of kinetoplastids including the human pathogenic trypanosomes. It was discovered in 1993, in the trypanosome Trypanosoma brucei and was the first hypermodified nucleobase found in eukaryotic DNA; it has since been found in other kinetoplastids, including Leishmania. Within these organisms Base J acts as a RNA polymerase II transcription terminator, with its removal in knockout cells being accompanied by a massive read-through at RNA polymerase II termination sites, which ultimately proves lethal to the cell.
Procyclins also known as procyclic acidic repetitive proteins or PARP are proteins developed in the surface coating of Trypanosoma brucei parasites while in their tsetse fly vector. The cell surface of the bloodstream form features a dense coat of variable surface glycoproteins (VSGs) which is replaced by an equally dense coat of procyclins when the parasite differentiates into the procylic form in the tsetse fly midgut.
Variant surface glycoprotein (VSG) is a ~60kDa protein which densely packs the cell surface of protozoan parasites belonging to the genus Trypanosoma. This genus is notable for their cell surface proteins. They were first isolated from Trypanosoma brucei in 1975 by George Cross. VSG allows the trypanosomatid parasites to evade the mammalian host's immune system by extensive antigenic variation. They form a 12–15 nm surface coat. VSG dimers make up ~90% of all cell surface protein and ~10% of total cell protein. For this reason, these proteins are highly immunogenic and an immune response raised against a specific VSG coat will rapidly kill trypanosomes expressing this variant. However, with each cell division there is a possibility that the progeny will switch expression to change the VSG that is being expressed. VSG has no prescribed biochemical activity.