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Living systems are all made of many molecular components that self- assemble, recognize as well as control each other and self- replicate ... How can it be that proteins, describable by the laws of physics, assemble themselves into cellular machines and structures, these into complete living cells, and the latter into whole organisms that require a whole new language for their description? [Opportunities in Molecular Biomedicine in the Era of  Teraflop Computing, March 3 & 4, 1999, Rockville, MD] http://www.ks.uiuc.edu/Publications/Reports/teraflop/node4.html

Related glossaries include Functional genomics, Assays, Labels, Signaling & Detection, Model organisms  Additional definitions appear in the In-depth glossary, after the Bibliography.

angiogenesis: The growth of new blood vessels - is an important natural process occurring in the body, both in health and in disease. The healthy body controls angiogenesis through a series of "on" and "off" switches: When angiogenic growth factors are produced in excess of angiogenesis inhibitors, the balance is tipped in favor of blood vessel growth. When inhibitors are present in excess of stimulators, angiogenesis is stopped. The normal, healthy body maintains a perfect balance of angiogenesis modulators. 

In many serious diseases states, the body loses control over angiogenesis. Angiogenesis- dependent diseases result when new blood vessels either grow excessively or insufficiently. Angiogenesis therapies - designed to "turn on" or "turn off" - are revolutionizing medicine by providing a unified approach for treating crippling and life-threatening conditions. Currently, more than 200 biotechnology, genomics, and medical device companies and every major pharmaceutical company is racing to develop new angiogenesis- based medicines. [Angiogenesis Foundation "Understanding Angiogenesis] http://www.angio.org/understanding/understanding.html

apoptosis:  One of the two mechanisms by which CELL DEATH occurs (the other being the pathological process of NECROSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA (DNA FRAGMENTATION) at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth. [MeSH] Also referred to as programmed cell death.

Apoptopedia, CellDeath.de, Germany   http://www.celldeath.de/encyclo/index.html

Apoptosis glossary, Biosource International, US http://www.biosource.com/content/literatureContent/apopglossary/glossary.asp

autosome:  A chromosome not involved in sex determination. The diploid human genome consists of 46 chromosomes, 22 pairs of autosomes, and 1 pair of  sex chromosomes (the X and Y chromosomes). [DOE] Related terms autosomal, somatic cells Clinical genomics glossary.

cell, cells: The smallest structural unit of living matter capable of functioning autonomously. [IUPAC Biotech]

The basic unit of any living organism. It is a small, watery, compartment filled with chemicals and a complete copy of the organism's genome. [NHGRI]

Narrower terms clone, embryonic stem cells ES, gametes, germ cells, hematopoietic stem cells, Mesenchymal Stem Cells MSC, pluripotent stem cells, somatic cell, stem cells In-depth CHO cells Chinese Hamster Ovary cells Related terms FACS, flow sorting

Related terms cell cycle, cell line, cell mapping, cellular component, cytogenetics, eukaryotes, host, hybridoma, Laser Capture Microdissection, multicellular, multipotent organelles, pluripotent, totipotent  In-depth cell culture, cell differentiation, cell fusion, cell patterning, cell strain, lysis, meiosis, mitosis, prokaryotes, subcellular fractionation, T cells

cell assays: Assays, labels, signaling & detection glossary

cell chips: Microarrays glossary

cell cycle:  The growth cycle of a cell from one division to the next. In eukaryotic cells the growth cycle is divided into the following 4 phases: G1- phase: the period of the cycle beginning after mitosis and preceding the initiation of DNA synthesis. S-phase: discrete period of cell cycle when most DNA synthesis occurs. G2- phase: period of cell cycle when cells contain twice the G1 complement of DNA. M-phase: division of the cell into two (cf. mitosis), each with one complete genome. [IUPAC Biotech]

The complex series of phenomena, occurring between the end of one cell division and the end of the next, by which cellular material is divided between daughter cells. [MeSH]  Related terms meiosis, mitosis; checkpoint control proteins Proteins glossary; Functional genomics glossary

cell function: The level at which we wish to understand the function of the cell determines to a large extent the degree of experimental reductionism required. The smallest building block required to understand the function of the cell appears to be the protein. While the genetic sequence provides the basic informational foundation of the cell, it is the network of protein- gene, protein- protein, and protein- metabolite interactions - the fluxes and flows of material and information -  which result in cell function.

Studies of whole cell dynamics currently employ optical imaging of diffusion, generally through the use of steady state or dynamic photobleaching recovery methods. Associated with such studies is the need to label specific intracellular entities. Expansion of these approaches to include the wealth of protein species in the cell will involve development of new labeling methods, new dyes and means of introducing them; widely scaling imaging techniques permitting examination of the whole cell or of intracellular compartments; NMR micro- imaging techniques, particularly those sensitive to chemical species; environmental EM techniques, which may provide the capability of rapid single cell microprobe analysis; creative evanescent wave approaches to characterizing the cell membrane; and new tools capable of mechanical assessment of global (and local) mechanical properties of the cell. ...

Ultimately, the systematic characterization of cell biology will be the result of the efforts of a great many laboratories integrated over many years. Archiving and interpreting (understanding) these results will require coordination at all levels. Whether or not the paradigm of the Human Genome Project is appropriate for integrating such cell- level studies was discussed at length with the full realization that overriding clinical, pharmaceutical, and cell biology questions may ultimately focus the effort more effectively than a central coordinating agency. Whatever organizational paradigm is employed, there are fundamental and overriding infrastructural issues which must be addressed at the outset, the most urgent of which are the development of enabling technologies and the creation of highly defined panels of cell types for the use of the research community [National Center for Research Resources "Integrated Genomics Technologies Workshop Report" Jan 1999]  http://www.ncrr.nih.gov/newspub/genomic.pdf 

cell mapping: Maps genomic & genetic 

cell physiology: While it [prediction of  the three- dimensional structure and function of proteins from their linear sequence information] would be a remarkable accomplishment, the future achievement of a satisfactory protein structure/ function predictive capability will simply provide a second important substratum upon which to begin the exploration of the intricacies of the operation of the living cell, since it is the interactions among cell proteins which, in large part, define cell physiology. Biologists understand a great deal about the protein constituents of cells, their roles in metabolism, the signaling roles of small molecules and selective modifications of intracellular proteins, and how cellular structures assemble themselves and transduce energy, but it is unlikely that a useful understanding of the cell will be possible until a quantitative appreciation of both rates and equilibria of molecular processes in the living cell is achieved. [National Center for Research Resources "Integrated Genomics Technologies Workshop Report" Jan 1999]  http://www.ncrr.nih.gov/newspub/genomic.pdf 

cellular component: The place in the cell where a gene product is active. [Gene Ontology Consortium "Gene Ontology: tool for the unification of biology Nature Genetics 25: 25-29 May 2000] Related terms Functional genomics biological function gene function,  Gene Ontology^TM Consortium; Proteins protein localization

chromosome: A self-replicating structure consisting of DNA complexed with various proteins and involved in the storage and transmission of genetic information; the physical structure that contains genes (cf., plasmid). Eukaryotic cells have a characteristic number of chromosomes per cell (cf. ploidy [haploid or diploid]) and contain DNA as linear duplexes ... The chromosomes of bacteria consist of double- stranded, circular DNA molecules. [MeSH]

One of the threadlike "packages" of genes and other DNA in the nucleus of a cell. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of  chromosomes, 46 in all: 44 autosomes and two sex chromosomes. Each parent contributes one chromosome to each pair, so children get half of  their chromosomes from their mothers and half  from their fathers. [NHGRI]

All human chromosomes should be sequenced to a "finished" state no later than 2003.  Narrower terms autosome, In-depth centromere, chromatin, euchromatin, heterochromatin, homologous chromosomes, telomere Related terms chromosome maps, cytogenetics, diploid, euchromatic, haploid, karyotype, ploidies, ploidy, In-depth somatic cell hybridization

Chromosome databases See Databases & software directory.

chromosome maps, chromosome mapping: Maps genomic & genetic glossary

clone: A population of genetically identical cells produced from a common ancestor. Sometimes also used to refer to a number of recombinant DNA molecules all carrying the same inserted sequence. [IUPAC Medicinal Chemistry, IUPAC Compendium] Narrower term clone bank

Clone was coined by Herbert J. Webber in 1903 for "a colony of organisms derived asexually from a single progenitor" and was quickly adopted by botanists and cell biologists. But the popular perception of cloning can be traced to Alvin Toffler's Future Shock (1970) and was quickly popularized (and extended to items such as computers). But Lee Silver, Professor of Molecular Biology and Public Affairs, Princeton Univ. concludes that "the scientific community has lost control over Webber's pleasant sounding little word. Cloning has a popular connotation that is impossible to dislodge. We must accept that democratic debate on cloning is bereft of any meaning. Science and Scientists would be better served by choosing other words to explain advances in developmental biotechnology to the public". [L. Silver "What are clones? They're not what you think they are" Nature 412 (6842): 21, 5 July 2001]

cloning: Using specialized DNA technology (see cloning vector) to produce multiple, exact copies of a single gene or other segment of DNA to obtain enough material for further study. This process is used by researchers in the Human Genome Project, and is referred to as cloning DNA. The resulting cloned (copied) collections of  DNA molecules are called clone libraries. A second type of cloning exploits the natural process of cell division to make many copies of an entire cell. The genetic makeup of these cloned cells, called a cell line, is identical to the original cell. A third type of cloning produces complete, genetically identical animals such as the famous  Scottish sheep, Dolly.  [DOE] Related term In-depth enucleated; directed evolution, molecular evolution

The process of making copies of a specific piece of DNA, usually a gene. When geneticists speak of cloning, they do not mean the process of making genetically identical copies of an entire organism. [NHGRI]

Of course many plants can be cloned (cuttings). And identical twins are (in a technical sense) clones, who can be organ donors for each other without immunosuppressants.

Narrower terms cloning vector

differentiation: The process by which cells become structurally and functionally specialized during embryonic development. [Life Sciences] Related terms  multipotent, pluripotent, totipotent, stem cells Narrower term cell differentiation Broader term In-depth developmental biology

In cancer, refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly- differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably.  [CancerNet]

diploid: The number of chromosomes in most cells except the gametes. In humans, the diploid number is 46. [NHGRI] Broader term ploidies, ploidy Related terms haploid;  Genetic variations haplotype

ES: See embryonic stem cells:

Embryonic stem cells ES: Cultured cells derived from the pluripotent inner cell mass of blastocyst- stage embryos. [NHLBI]

Use of stem cells has a number of promising research applications.  The British government has recently approved proposals for allowing stem cell research [Nature 409 (6819): 445, 25 Jan. 2001 and Nature 409:5, 2001] although the rest of Europe was predicted to continue to outlaw this research. Broader term stem cells Related term hematopoietic stem cells.

eukaryotes: Organisms whose cells have their genetic material packed in a membrane- surrounded, structurally discrete nucleus and with well- developed cell organelles.  Eukaryotes include all organisms except archaebacteria and eubacteria (cg. prokaryotes). [IUPAC Biotech]

FACS: Sequencing glossary In-depth

flow cytometry: Sequencing glossary In-depth

flow sorting:  Sequencing glossary In-depth

fusion: The amalgamation of two distinct cells or macromolecules into a single integrated unit. [IUPAC Biotech] Narrower term cell fusion.

gamete: Mature male or female reproductive cell (sperm or ovum) with a haploid set of chromosomes (23 for  humans). [DOE] Related term germ cells

germ cells: The reproductive cells in multicellular organisms. Includes Ovum (Oocytes, Oogonia,   Zona Pellucida , Zygote) and Spermatozoa (Sperm Head + , Sperm Tail, Spermatids, Spermatocytes, Spermatogonia  [MeSH] Related terms gamete, germline mutations

germline mutation: Clinical genomics glossary

haploid: The number of chromosomes in a sperm or egg cell, half the diploid number. [NHGRI] 

A single set of chromosomes (half the full set of genetic material), present in the egg and sperm cells  of animals and in the egg and pollen cells of plants. Human beings have 23 chromosomes in their reproductive cells. Compare diploid.  [DOE]  Broader term ploidies, ploidy Related terms diploid; Genetic variations haplotype

haplotype: Genetic variations glossary

hematopoiesis: The formation and development of blood cells involving both proliferation and differentiation from stem cells. In adult mammals usually occurs in bone marrow. [18 Nov 1997, OMD]

hematopoietic stem cells: Progenitor cells from which all blood cells derive.  [MeSH] 

An unspecialized precursor cell that will develop into a mature blood cell. [NHGRI] 

Related terms embryonic stem cells, hematopoiesis, mesenchymal stem cells, multipotent, pluripotent, totipotent; Broader term stem cells.

human pluripotent stem cells: See pluripotent stem cell research, human.

hybridoma: Pharmaceutical biology glossary

in silico biology, in silico modeling: Molecular modeling glossary

Laser Capture Microdissection LCM: A method for procuring pure cells from specific microscopic regions of tissue sections. These tissue sections may contain many cell types (for example connective, blood vessel, muscle, adipose and immune cells) interspersed and effectively locked together by adhesive interactions. Cancer cells, such as those in prostate cancer, are usually found in such heterogeneous environments. LCM permits one to "put a bead" on these cells to isolate them and obtain high levels of signal in gene expression and protein expression analysis.

The procedure is simple in practice, with the technician placing the cells of interest from a tissue section in the center of the microscope field, and pushing a button that activates an integral laser. The laser activates an area of the film immediately above the center of view and the film bonds with the targeted cells. When the film is lifted, the cells are carried with it, leaving behind the unwanted material. The method was developed at NIH and is being developed commercially with Arcturus Engineering, Inc. It is highly reproducible and accurate, and amenable to automation. [CHI Summit Proteomics]

Laser Capture Microdissection website, NIH http://dir.nichd.nih.gov/lcm/lcm.htm

library: An unordered collection of clones (i.e., cloned DNA from a particular organism), whose relationship to each other can be established by physical mapping. [DOE] 

This is different from combinatorial library in Drug discovery & development (or more general meanings of  "library").  Narrower terms gene library, genomic library; Microarrays glossary arrayed library. 

mesenchymal: Refers to cells that develop into connective tissue, blood vessels, and lymphatic tissue. [Cancernet] Part of the embryonic mesoderm.

Mesenchymal Stem Cells MSCs The body's storehouse of potential spare parts, pockets of unspecialized cells, tucked into a variety of places, that can migrate to an injury and, responding to signals in the milieu, embark on a normal developmental pathway to become what's needed. They are not totipotent, as are ES cells, but pluripotent, capable of differentiating into connective tissue and its derivatives. Neither are they as far along the developmental trajectory as hematopoietic stem cells used to replenish bone marrow,3 or the neural stem cells that researchers recently rerouted to produce hematopoietic cells.4 [Ricki Lewis "Human Mesenchymal Stem Cells Differentiate in the Lab" Scientist 13[8]1, Apr. 12, 1999] http://www.the-scientist.com/yr1999/apr/lewis_p1_990412.html

Related terms mesenchymal, mesoderm

mesoderm <embryology> Middle of the three germ layers, gives rise to the musculoskeletal, blood, vascular and urinogenital systems, to connective tissue (including that of dermis) and contributes to some glands. [OMD]

metabolism: The term metabolism comprises the entire physical and chemical processes involved in the maintenance and reproduction of life in which nutrients are broken down to generate energy and to give simpler molecules (catabolism) which by themselves may be used to form more complex molecules (anabolism).

In case of heterotrophic organisms, the energy evolving from catabolic processes is made available for use by the organism.   [IUPAC Medicinal Chemistry] See Pharmaceutical biology glossary for metabolism in medicinal chemistry definition. Related terms organelles

metabolite: Any intermediate or product resulting from metabolism. [IUPAC Biotech]

mitochondria; Organelles appearing in all eukaryotic cells which produce ATP as useful energy for the cell by oxidative phosphorylation. The proteins for the adenoseine  5’- triphosphate (ATP)- generating electron transport of the respiration chain are located in the inner mitochondrial membrane. Mitochondria contain many enzymes of the citric acid cycle and for fatty acid [beta]- oxidation. Many of them are coded for by nuclear DNA. [IUPAC Biotech] Related terms  In-depth ATP,  mitochondrion; mitochondrial genes Gene definitions

molecular motors: Miniaturization glossary

multicellular: Practically speaking, few processes peculiar to multicellular organisms have meaning when abstracted from anatomy, a particularly good example being developmental processes. The general consensus is that 'when it gets multicellular, it gets complicated'. [Minutes of Gene Ontology Consortium Meeting 4- 6 November 2000 (Berkeley 2000 Meeting)] http://www.geneontology.org/minutes.berkeley.20001106.txt

multipotent: Cells capable of differentiating into many cell types. Narrower terms pluripotent, totipotent.

nucleus: The central cell structure that houses the chromosomes. [NHGRI] Related terms In-depth chromosomes, enucleated, mitochondria, organelles.

photobleaching: Useful for determining cellular structure. Assays, labels, signaling & detection glossary

ploidies:  The degree of replication of the chromosome set in the karyotype. [MeSH]

ploidy: Indicates the number of sets of chromosomes present in an organism, e.g. haploid (one) or diploid (two). [IUPAC Biotech]

pluripotent: Cells able to develop into most specialized types of cells. Broader term totipotent; Narrower term multipotent. Related term stem cells

pluripotent stem cell research - human: Because pluripotent stem cells give rise to almost all of the cells types of the body, such as muscle, nerve, heart, and blood, they hold great promise for both research and health care. This advance in human biology continues to generate enthusiasm among scientists, patients suffering from a broad range of diseases, including cancer, heart disease and diabetes, and their families. [NIH, Fact Sheet on Human Pluripotent Stem Cell Research Guidelines,  Jan. 2001]  http://www.nih.gov/news/stemcell/stemfactsheet.htm

Guidelines for Research Using Human Pluripotent Stem Cells, NIH, Aug. 25, 2000 http://www.nih.gov/news/stemcell/stemcellguidelines.htm

ribosomes:  Subcellular unit composed of specific rRNA molecules and a large number of proteins that are responsible for protein synthesis. [IUPAC Compendium] 

Cellular organelle that is the site of protein synthesis. [NHGRI]

Early in 1958, a three-day symposium on microsomal particles in protein synthesis met at MIT, sponsored by the Biophysical Society, organized by Richard Roberts, who was head of a group at the Carnegie Institution in Washington... The most important development at the meeting was semantic. Roberts suggested that for clear and handy distinction between the particles and the amorphous cellular fraction of protein and fat in which they were found, the particles themselves should be called "ribosomes" - short for "ribonucleoprotein particles of the microsome fraction." The new term quickly spread into general use. [HJ Freeman, Eighth Day of Creation Cold Spring Harbor Laboratory Press, 1996, p. 338]

From the Greek soma body

second messenger: An intracellular metabolite or ion increasing or decreasing as a response to the stimulation of receptors by agonists, considered as the "first messenger". This generic term usually does not prejudge the rank order of intracellular biochemical events. [IUPAC Medicinal Chemistry] 

second messenger systems: Systems in which an intracellular signal is generated in response to an intercellular primary messenger such as a hormone or neurotransmitter. They are intermediate signals in cellular processes such as metabolism, secretion, contraction, phototransduction, and cell growth. Examples of second messenger systems are the adenyl cyclase- cyclic AMP system, the phosphatidylinositol diphosphate- inositol triphosphate system, and the cyclic GMP system. [MeSH]  

A multi-step signal amplification process used by the cell to transmit, for example, signals from many hormones that cannot enter the cell directly. [NIGMS]

single cell detection: Assays, labels, signaling & detection glossary

single cell NMR imaging: NMR & X-ray crystallography glossary

single cell studies: Recent developments in optical imaging, particularly quantitative fluorescence microscopy; ultra- small volume sampling and analysis; incorporation of optically useful probes, such as green fluorescent protein into cellular constituents; combinations of photobleaching and imaging; and optical approaches to determining the rates and equilibria of intracellular processes clearly indicate the enormous potential of in vivo single cell studies for our understanding of cell physiology, as well as the remaining substantial difficulties. Biologists need tools capable of analyzing the genomic and proteomic information of the living single cell. The quantitation, localization, and identification of proteins within the cell, as well as full characterization of intracellular interactions involving proteins in their structural, catalytic, and control roles, will be essential for development of a comprehensive and integrative view of cell physiology. Furthermore, development of highly specific drugs must ultimately involve screening against in vivo cellular processes. Thus, the envisioned technology development will enable the application of profoundly powerful combinatorial approaches to understanding and regulating the interior world of the cell, as well as characterizing the cell- physiological consequences of rare phenotypes - particularly those associated with disease. [NCRR, NHGRI, NIGMS Integrated Genomics Technologies Request for Applications, Dec. 23, 1998] http://grants.nih.gov/grants/guide/rfa-files/RFA-RR-99-003.html

somatic cell:  Any cell in the body except gametes and their precursors. [DOE] Are the precursors stem cells?

See also somatic cells Clinical genomics glossary

All body cells, except the reproductive cells. [NHGRI]

somatic cell hybridization:  In somatic cell hybridization, human cells and rodent tumor cells are fused (hybridized); over time, after the chromosomes mix, human chromosomes are preferentially lost from the hybrid cell until only one or a few remain. Those individual hybrid cells are then propagated and maintained as cell lines containing specific human chromosomes. Improvements to this technique have generated a number of hybrid cell lines, each with a specific single human chromosome. [Primer in Molecular Genetics, Oak Ridge National Lab, US]  http://www.ornl.gov/hgmis/publicat/primer/intro.html

spliceosomes: Organelles in which the splicing and excision reactions that remove introns from precursor messenger RNA molecules occur. One component of a spliceosome is five small nuclear RNA molecules (U1, U2, U4, U5, U6) that, working in conjunction with proteins, help to fold pieces of RNA into the right shapes and later splice them into the message. [MeSH] Related term splicing Sequences DNA & beyond

stem cells: Relatively undifferentiated cells of the same lineage (family type) that retain the ability to divide and cycle throughout postnatal life to provide cells that can become specialized and take the place of those that die or are lost. Includes Fibroblasts, Hematopoietic Stem Cells, Erythroid Progenitor Cells, Tumor Stem Cell [MeSH] Narrower terms embryonic stem cells, hematopopoietic stem cells.

NIH stem cell information  http://www.nih.gov/news/stemcell/

subcellular fractionation: Concentrating a sample by separating out certain compartments of the cell. Allows study of cellular compartments and can provide greater resolution and sensitivity. [CHI Proteomics]

systems biology: The Institute's mission is to carry out a new approach to biology termed systems biology and to develop the tools necessary for these pioneering approaches. The Institute [for Systems Biology] will initially focus on systems approaches to the immune system; the correlation of genomic variability with physiology and disease predisposition; the detailed analysis of a model micro- organism; and the study of diseases such as cancer, heart disease and auto-immunity. ... Dr. [Leroy] Hood’s laboratory has evolved over the past three decades toward a view that systems biology is the key to understanding the biological codes that shape the development and differentiation of cells and organisms. [The Institute for Systems Biology, Seattle WA, US] http://www.systemsbiology.org/vision.html

telomere: A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs. [MeSH]  Involved in aging and senescence.

tissue culture: See cell culture. [IUPAC Biotech]

tissue engineering: Biomaterials glossary

totipotent <embryology> Capable of giving rise to all types of differentiated cell found in that organism. A single totipotent cell could, by division, reproduce the whole organism. [OMD]     See also multipotent, pluripotent, stem cells.

vector: 1. A DNA molecule (plasmid, virus, bacteriophage, artificial or cut DNA molecule) capable of being replicated and bearing cloning sites for the introduction of foreign DNA, used to introduce this DNA into host cells. 2. Any organism that transmits a disease between two hosts. [IUPAC Biotech]

An agent, such as a virus or a small piece of DNA called a plasmid, that carries a modified or foreign gene. When used in gene therapy, a vector delivers the desired gene to a target cell. [NHGRI]

The two different senses of the IUPAC definitions should be clear from context.  The organisms transmitting pathogens can be insects or small animals. Vectors used in gene therapy are not pathogenic.

Narrower terms In-depth BAC Bacterial Artificial Chromosome, cloning vector, genetic vector, plasmids.

Vector databases see Databases & software directory.

IUPAC definitions are reprinted with the permission of the International Union of Pure and Applied Chemistry.

Bibliography

Chapter on cell biology from MIT's Biology Hypertextbook  http://esg-www.mit.edu:8001/esgbio/cb/cbdir.html

[Lackie] JM and JAT Dow, Dictionary of Cell & Molecular Biology, Academic Press, 3^rd ed., 1999. 7,000+ definitions.   http://on.to/dictionary

WWW Virtual Library Cell Biology http://vl.bwh.harvard.edu/

WWW Virtual Library Developmental Biology http://sdb.bio.purdue.edu/Other/VL_DB.html

Alpha glossary List

In-depth Cell Biology definitions

Adenosine Triphosphate ATP: Adenosine 5'- (tetrahydrogen triphosphate). An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter. [MeSH]

BAC: See Bacterial Artificial Chromosome.

Bacterial artificial chromosome (BAC): A vector used to clone DNA fragments (100- to 300-kb insert size; average, 150 kb) in Escherichia coli cells. Based on naturally occurring F-factor plasmid found in the bacterium E. coli. Compare cloning vector.  [DOE] Related term BAC maps. Maps, genetic & genomic glossary.

CHO cells: Cell line derived from the ovary of the Chinese hamster, Cricetulus griseus. The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems  for the study of genetic alterations in cultured mammalian cells.  [MeSH]

cell culture: The in vitro propagation of animal of plant cells, in an artificial nutrient medium. [IUPAC Biotech]

cell differentiation: Progressive restriction of the developmental potential and increasing specialization of function which takes place during the development of the embryo and leads to the formation of specialized cells, tissues, and organs. [MeSH] Related terms multipotent, pluripotent, stem cells, totipotent

cell fusion: Fusion of somatic cells in vitro or in vivo, which results in somatic cell hybridization. [MeSH] Broader term fusion. Narrower term electroporation

cell line: Defined unique population of cells obtained by culture from a primary implant through numerous generations. [IUPAC Tox] Often mammalian. Narrower terms In-depth CHO cells, cell strain

cell patterning: The shape of a cell can tell us much about its status.  The fate of a cell, whether it will divide, differentiate, or undergo apoptosis, is closely dependent on whether it is spread or rounded.  However it is still unclear how cell shape is sensed and how the signal is transduced.  In recent years, various forms of photolithography and micro- fabrication technology have made it possible to precisely control the shape of a cell.  These technologies involve creating micron scale patterns of cell adhesive islands on a non- adhesive background.  Cells seeded on patterned surfaces are only able to attach to the adhesive areas and consequently adopt the shape of the adhesive island.  However, the current microfabrication technology only allows patterning on rigid surfaces.  Thus after the cell has attached, the experimenter cannot change the shape of the cell nor control the rate of cell spreading.  Our goal is to develop a simple patterning technique on flexible polymer surfaces.  Though stretching the polymer substrate which cells are attached to, we can control the time as well as the magnitude of cell shape changes.  By fully taking advantage of this capability, experiments designed to elucidate the shape signaling pathway can be performed more elegantly and in a more controlled manner.  For example, we can now allow cells to fully attach before changing the shape of the cell.  This way, biochemical signals that result from the seeding and initial attachment of the cell from solution will no longer add noise to the data.  A better understanding of the pathway cell use to sense and respond to shape changes may lead to new treatments for various diseases. [John L. Tan, Biomedical Engineering Dept. Johns Hopkins Univ.] http://www.bme.jhu.edu/labs/cchen/John/patterning.htm

cell strain: Cells having specific properties or markers derived from a primary culture or cell line. [IUPAC Tox]

centromere: The clear constricted portion of the chromosome at which the chromatids are joined and by which the chromosome is attached to the spindle during cell division. [MeSH]

Chinese hamster ovary cells: See CHO cells.

chromatin: The material of CHROMOSOMES. It is a complex of DNA, HISTONES, and nonhistone proteins (CHROMOSOMAL PROTEINS, NON- HISTONE) found within the nucleus of a cell. [MeSH]

clone bank: Genomic library, a collection of clones made from a set of randomly generated overlapping DNA fragments representing the entire genome of an organism. [Schlindwein] Related term: genomic library

cloning vector: DNA molecule originating from a virus, a plasmid, or the cell of a higher organism into which another DNA fragment of appropriate size can be integrated without loss of the vectors capacity for self replication; vectors introduce foreign DNA into host cells, where it can be reproduced in large quantities. Examples are plasmids, cosmids, and yeast artificial chromosomes [YACs]; vectors are often recombinant molecules containing DNA sequences from several sources. [DOE]

cytogenetics: Branch of genetics which correlates the structure and number of chromosomes as seen in isolated cells with variation in genotype and phenotype. Related term: phenotype.

developmental biology:  The field of biology which deals with the process of the growth and differentiation of an organism.  [MeSH]

enucleated: Cell from which the nucleus has been removed, used for nuclear transfer to produce a cloned animal from differentiated cells.

euchromatic: Containing euchromatin, the extended regions of chromosomes. These extensions become most dense - and thus most visible microscopically - during the metaphase of the cell cycle. [MeSH]

euchromatin: Chromosome regions that are loosely packaged and more accessible to RNA polymerases than HETEROCHROMATIN. These regions also stain differentially in CHROMOSOME BANDING preparations.  [MeSH]

In humans are particularly rich in genes.

extracellular matrix: A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere. [MeSH]

gene library: A collection of cloned DNA fragments from a variety of species. [IUPAC Biotech]

genetic vector : Artificial nucleic- acid constructs, usually based on the insertion elements of viruses or plasmids, used for transfection and cloning. [MeSH]

genomic library: A collection of clones made from a set of randomly generated overlapping DNA fragments representing the entire genome of an organism. [DOE]

Golgi Apparatus:  A stack of flattened vesicles that functions in post- translational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. [MeSH (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)]

An organelle composed of membranous sacs that packages proteins into vesicles and sends them to the cell's surface or to lysosomes.  [NIGMS]

heterochromatin: The portion of chromosome material that remains condensed and is transcriptionally inactive during INTERPHASE. [MeSH]

Highly repetitive lengths of DNA with little genetic information.

homologous chromosomes: A pair of chromosomes containing the same linear gene sequences, each derived from one parent. [DOE]

host: A cell whose metabolism is used for growth and reproduction of a virus, plasmid, or other form of foreign DNA.  [IUPAC Biotech]

host-vector system: A compatible combination of host (e.g. bacteria) and vector (e.g. plasmid) that allows propagation of DNA. [IUPAC Biotech]

karyotype: A photomicrograph of an individuals chromosomes arranged in a standard format showing the number, size, and shape of each chromosome type; used in low-resolution physical mapping to correlate gross chromosomal abnormalities with the characteristics of specific diseases. [DOE] 

lysis: Cell rupture caused by physical or chemical means, or by phage infection and propagation leading to the release of the cell content; also the death of microorganisms after the stationary phase of a batch fermentation. [IUPAC Biotech]

meiosis: The reductive cell division which results in daughter cells containing one copy of each of the chromosomes of the parent. The entire meiotic process involves two separate divisions (meiosis I and meiosis II). The first division is a true reductive division with the chromosome number being halved, whereas the second division resembles mitosis in many ways. Thus, a diploid parental cell will give rise to haploid daughter cells (cf. ploidy). IUPAC Biotech] Related term cell cycle

Microbial Cell Project: Dept. of Energy, US http://microbialcellproject.org/  

mitochondrion: The cell organelle that converts the energy in sugars into ATP, thereby fueling the cell. [NIGMS]

mitosis: The process whereby a cell nucleus divides into two daughter nuclei, each having the same genetic component as the parent cell. [IUPAC Biotech] 

A method of indirect cell division by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes of the somatic cells of the species [MeSH]  Related term cell cycle

morphometry: Measurement of shape, structure and form.  Used in a variety of disciplines, including environmental studies, geology, imaging and cell biology.

nuclear transfer: See under enucleated.

organelles: Separated components within a cell with specialized functions, e.g. nuclei (containing most of the genetic material), mitochondria (respiratory energy supply for the cell), chloroplasts (location of photosynthesis) etc. [IUPAC Biotech]

Specific, usually subcellular, particles of membrane- bound organized living substances present in  practically all eukaryotic cells, including mitochondria, the Golgi complex, endoplasmic reticulum, lysosomes, centrioles and the cell center, as well as the plastids of plant cells. Includes also the minute organs of protozoa concerned with such functions as locomotion and metabolism. [MeSH]

plasmid, plasmids: Extrachromosomal genetic element consisting generally of circular double-stranded DNA, which can replicate independently of chromosomal DNA.  Used as vectors for cloning DNA in bacteria or yeast host cells. [IUPAC Bioinorganic].

Autonomously replicating, extrachromosomal circular DNA molecules, distinct from the normal bacterial genome and nonessential for cell survival under nonselective conditions. Some plasmids are capable of integrating into the host genome. A number of artificially constructed plasmids are used as cloning vectors. [DOE]

prokaryote: A unicellular organism characterized by the absence of a membrane- bound nucleus.. Includes bacteria, blue- green algae (Cyanobacteria) and mycoplasmas. [IUPAC Biotech]

T cells: Lymphocytes responsible for cell-mediated immunity. Two types have been identified: cytotoxic and helper T-lymphocytes. [MeSH]