Glossary

Active immunity

A type of acquired immunity whereby resistance to a disease is built up by either having the disease or receiving a vaccine to it.

Adjuvant

Insoluble material that increases the formation and persistence of antibodies when injected with an antigen.

Allele

Any of several alternative forms of a gene.

Allogenic

Of the same species, but with different genotype.

Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes. It is the most common cause of dementia.

Amino acids

Building blocks of proteins. There are 20 common amino acids used to construct proteins.

Amplification

The process of increasing the number of copies of a particular gene or chromosomal sequence

Antibody (cellular)

An antibody which has the ability to attach itself onto the membrane of certain cells, a property which gives these cells a specific activity against an antigen.

Anticodon

Triplet of nucleotide bases (codon) in transfer RNA that pairs with (is complementary to) a triplet in messenger RNA.

Bacteriophage

Virus that lives in and kills bacteria. Also called phage.

Bacterium

Any of a large group of microscopic organisms with a very simple cell structure. Some manufacture their own food, some live as parasites on other organisms and some live on decaying matter.

Base

On the DNA molecule, one of the four chemical units that, according to their order and pairing , represent the different amino acids. The four bases are: adenine (A), cytosine ( C), guanine (G) and thymine (T). In RNA, uracil (U) substitutes for thymine.

Base pair

Two nucleotide bases on different strands of the nucleic acid molecule that bond together. The bases can pair in only one way: adenine with thymine (DNA) or uracil (RNA) and guanine with cytosine.

Biocatalyst

In bioprocessing, an enzyme that activates or speeds up a biochemical reaction.

Biochip

An electronic device that uses organic molecules to form a semiconductor.

Bioconversion

Chemical restructuring of raw materials by using a biocatalyst.

Bioinformatics

A science that uses advanced computing techniques for management and analysis of biological data. Bioinformatics is particularly important as an adjunct to genomic research, which generates a large amount of complex data, involving DNA sequences and hundreds of thousands of genes.

Biolistic device

Shooting microscopic DNA-coated particles into target cells.

Bioreactor

Vessel used for bioprocessing: cultivation of cells under controlled conditions.

Candidate gene

A gene whose function or location suggests that it may be responsible for a disease or trait in a population of individuals.

Catalyst

An agent (such as an enzyme or a metallic complex) that facilitates a reaction but is not itself changed during the reaction.

Cell

The smallest structural unit of living organisms that is able to grow and reproduce independently.

Cell bank

A uniform pool of cells, distributed into vials and preserved, typically by freezing in liquid nitrogen. A viral is thawed to start each new production cycle.

Cell line

Cells which result from the subcultivations of primacy cell cultures.

Cell-mediated immunity

Acquired immunity in which T lymphocytes play a predominant role. Development of the thymus in early life is critical to the proper development and functioning of cell-mediated immunity.

Chimera

The individual (animal or lower organism) produced by grafting an embryonic part of one species onto an embryo of either the same or a different specie.

Chromosomes

Threadlike components in the cell that contain DNA and proteins. Genes are carried on the chromosomes.

Clone

A term that is applied to genes, cells or entire organisms that are derived from -and are genetically identical to – a single common ancestor gene, cell or organism, respectively.

Codon

A sequence of three nucleotide bases that specifies an amino acid or represents a signal to stop or start a function.

Complementary DNA

DNA synthetised from a messenger RNA. This type of DNA is used for cloning or as a DNA probe for locating specific genes in DNA hybridisation studies.

Continuous cell-line

A cell line which has acquired the characteristic of being “immortal”, i.e. capable of growing indefinitely in culture.

Crossing-over

Exchange of genes between two paired chromosomes.

Culture

As a noun, cultivation of living organisms in prepared medium; as a verb, to grow in prepared medium.

Cytogenetics

Study of the cell and its heredity-related components, especially chromosomes.

Cytoplasm

Cellular material that is within the cell membrane and surrounds the nucleus.

Cytotoxic

Able to cause cell death

Deoxyribonucleic acid (DNA)

The molecule that carries the genetic information for most living systems. The DNA molecule consists of four bases and a sugar-phosphate backbone, arranged in two connected strands to form a double helix.

Differential gene expression (DGE)

A laboratory technique that compares the body of expressed (switched on) genes in different cells under different conditions by measuring the mRNA in a diseased liver cell with that in a healthy liver cell.

Differentiation

The process of biochemical and structural changes by which cells become specialised in form and function.

Diploid

A cell with two complete sets of chromosomes

DNA sequence

The order of nucleotide bases in the DNA molecule.

Embryo

Term used to describe the early stages of foetal growth, from conception to the eight week of pregnancy.

Enzyme

A protein catalyst that facilitates specific chemical or metabolic reactions necessary for cell growth and reproduction.

Escherichia coli (E. coli)

A bacterium that inhabits the intestinal tract of most vertebrates. Much of the work using recombinant DNA techniques has been carried out with this organism because it has been genetically well characterised.

Eukaryote

A cell or organism containing a true nucleus, with a well-defined membrane surrounding the nucleus. All organisms except bacteria, viruses and blue-green algae are eukaryotic.

Exon

In eukaryotic cells, that part of the gene that is transcribed into messenger RNA and encodes a protein.

Expressed sequence tags (EST)

Partial gene sequences

Expression

Gene expression, the process of transferring the information encoded in the gene to a functional product e.g. a protein.

Gene

A segment of chromosomes. Some genes direct the syntheses of proteins, while others have regulatory functions.

Gene mapping

Determination of the relative locations of genes on a chromosome.

Gene sequencing

Determination of the sequence of nucleotide bases in a strand of DNA.

Gene therapy

The replacement of a defective gene in an organism suffering from a genetic disease. Recombinant DNA techniques are used to isolate the functioning gene and insert it into cells. Over 300 single-gene genetic disorders have been identified in humans. A significant percentage of these may be amenable to gene therapy.

Genetic

A technology used to alter the genetic material of living modification cells in order to make them capable of producing new substances or performing new functions.

Genetic code

The mechanism by which genetic information is stored in living organisms. The code uses sets of three nucleotide bases (codons) to make the amino acids that, in turn, constitute proteins.

Genetic screening

The use of a specific biological test to screen for inherited diseases or medical conditions. Testing can be conducted prenatally to check for metabolic defects and congenital disorders in the developing foetus as well as postnatally to screen for carriers of heritable diseases.

Genetic testing

The analysis of an individual’s genetic material. Genetic testing can be used to gather information on an individual’s genetic predisposition to a particular health condition, or to confirm a diagnosis in genetic disease.

Genetics

The study of traits passed on from parent to child and variation of those traits within and between individuals.

Genome

The total hereditary material of a cell, comprising the entire chromosomal set found in each nucleus of a given species.

Genotype

The type of gene or genetic marker an individual has at a specific location in his or her genome. A genotype consists of 2 alleles since chromosomes come in pairs. However, a genotype on either of the male sex chromosomes (X or Y) consists of a single allele.

Granulocytes

One of three types of white blood cells. Granulocytes digest bacteria and other parasites.

Haploid

A cell with half the usual number of chromosomes, or only one chromosome set. Sex cells are haploid.

Haplotype

A series of alleles found at linked loci on a single chromosome.

Hapten

The portion of an antigen that determines its immunological specificity. When coupled to a large protein, a hapten stimulates the formation of antibodies to the two-molecules complex. Also called antigenic determinant.

Heredity

Transfer of genetic information from parent cells to progeny

Histocompatibility antigen

An antigen that causes the rejection of grafted material from an animal different in genotype from the host animal

Hormone

A chemical or protein that acts as a messenger or stimulatory signal, relaying instructions to stop or start certain physiological activities. Hormones are synthesised in one type of cell and then released to direct the function of other cell types.

Host

A cell or organism used for growth of a virus, plasmid or other form of foreign DNA, or for the production of cloned substances.

Host-vector system

Combination of DNA-receiving cells (host) and DNA-transporting substance (vector) used for introducing foreign DNA into a cell.

Hybridisation

Production of offspring, or hybrids, from genetically dissimilar parents. The term is also used to refer to the binding of complementary strands of DNA or RNA.

Hybridoma

The cell produced by fusing two cells of different origin. In monoclonal antibody technology, hybridomas are formed by fusing an immortal cell (one that divides continuously) and an antibody-producing cell.

Immune response

The response of the immune system to challenge by a foreign antigen.

Immune serum

Blood serum containing antibodies.

Immune system

The aggregation of cells, biological substances (such as antibodies) and cellular activities that work together to provide resistance to disease.

Immunity

Nonsusceptibility to a disease or to the toxic effects of antigenic material.

Immunoglobulin

General name for proteins that function as antibodies. These proteins differ somewhat in structure and are grouped into five categories on the basis of these differences.

Immunology

Study of all phenomena related to the body’s response to antigenic challenge.

In situ

In its original or natural place or position

In vitro

Literally, in “glass”. Performed in a test tube or other laboratory apparatus.

In vivo

In the living organism.

Interferon

A class of lymphokine proteins important in the immune response. There are 3 major types of interferon: alpha, beta, gamma. Interferons inhibit viral infections and may have anticancer properties.

Interleukin

A type of lymphokine that regulates the growth and development of white blood cells. 12 interleukins have been identified to date.

Intron

In eukaryotic cells, a sequence of DNA that is contained in the gene but does not encode for protein. The presence of introns “splits” the coding region of the gene into segments called exons.

Isogenic

Of the same genotype

Leukocyte

A colourless cell in the blood, lymph and tissues that is an important component of the body’s immune system.

Library

A set of cloned DNA fragments.

Ligase

An enzyme used to join DNA or RNA segments together. They are called DNA ligase or RNA ligase, respectively.

Linker

A fragment of DNA with a restriction site that can be used to join DNA strands.

Lymphocyte

A type of leukocyte found in lymphoblastic tissue in the blood, lymph nodes and organs. Lymphocytes are continuously made in the bone marrow and mature into antibody-forming cells. Lymphocyte T : Their maturation is controlled by the thymus. They are thymus-dependent and can be “helper” or “killer”. They are the keepers of immunological memory. Lymphocyte B : Bone marrow-derived antibody producing immunoglobulin after maturation.

Lymphokine

A class of soluble proteins produced by white blood cells that play a role, as yet not fully understood, in the immune response.

Macrophage

A type of white blood cell produced in blood vessels and loose connective tissues that can ingest dead tissues and cells and is involved in producing interleukin.

Medium

A substance containing nutrients needed for cell growth.

Medium

A substance containing nutrients needed for cell growth.

Meiosis

Process of cell reproduction whereby the daughter cells have half the chromosome number of the parent cells. Sex cells are formed by meiosis.

Messenger RNA (mRNA)

Nucleic acid that carries instructions to a ribosome for the synthesis of a particular protein.

Microinjection

The injection of DNA using a very thin needle into a cell.

Microorganism

Any organism that can be seen only with the aid of a microscope.

Mitosis

Process of cell reproduction whereby the daughter cells are identical in chromosome number to the parent cells.

Molecular genetics

Study of how genes function to control cellular activities.

Monoclonal antibody (Mab)

Highly specific, purified antibody that is derived from only one clone of cells and recognises only one antigen.

Monocytes

One of three types of white blood cells. Monocytes are precursors to macrophages.

Mutant

A cell that manifests new characteristics due to a change in its DNA.

Natural active immunity

Immunity that is established after the occurrence of a disease.

Natural killer cell (NK)

A type of leukocyte that attacks cancerous or virus-infected cells without previous exposure to the antigen. NK cell activity is stimulated by interferon.

Natural passive immunity

Immunity conferred by the mother on the foetus or new-born.

Nucleic acid

Large molecules, generally found in the cell’s nucleus and/or cytoplasm, that are made up of  nucleotide bases. The two kinds of nucleic acid are DNA and RNA.

Nucleotides

The building blocks of nucleic acids. Each nucleotide is composed of sugar, phosphate and one of four bases. The sequence of the base within the nucleic acid determines what proteins are made.

Nucleus

The structure within eukaryotic cells that contains chromosomal DNA.

Oligonucleotide

A polymer consisting of a small number (about two to ten) of nucleotides.

Oncology

Study of tumours.

Oncology

Study of tumours.

Operator gene

A region of the chromosome, adjacent to the operon, where a repressor protein binds to prevent transcription of the operon.

Operon

Sequence of genes responsible for synthesising the enzymes needed for biosynthesis of a molecule. An operon is controlled by an operator gene and a repressor gene.

Osteoporosis

Osteoporosis is a disease of bone in which the bone mineral density (BMD) is reduced, bone microarchitecture is disrupted, and the amount and variety of non-collagenous proteins in bone is changed. Osteoporotic bones are more susceptible to fracture. Osteoporosis is defined by the World Health Organization (WHO) as either a bone mineral density 2.5 standard deviations below peak bone mass (20-year-old person standard) as measured by DXA, or any fragility fracture. While treatment modalities are becoming available, prevention is still the most important way to reduce fracture. Due to its hormonal component, more women, particularly after menopause, suffer from osteoporosis than men.

Parkinson’s disease

Parkinson’s disease (also known as Parkinson disease or PD) is a degenerative disorder of the central nervous system that affects the control of muscles, and so may affect movement, speech and posture. Parkinson’s disease belongs to a group of conditions called movement disorders. It is often characterized by muscle rigidity, tremor, a slowing of physical movement (bradykinesia), and in extreme cases, a loss of physical movement (akinesia). The primary symptoms are the results of excessive muscle contraction, normally caused by the insufficient formation and action of dopamine, which is produced in the dopaminergic neurons of the brain. Secondary symptoms may include high level cognitive dysfunction and subtle language problems. PD is both chronic, meaning it persists over a long period of time, and progressive.

Passive immunity

Immunity acquired from receiving pre-formed antibodies.

Peptide

Two or more amino acids joined by a linkage called a peptide bond.

Phagocyte

A type of white blood cell that can ingest invading microorganisms and other foreign material.

Pharmacogenetics

Study of the DNA sequence variation as it relates to differential drug response.

Pharmacogenomics

In its broader sense, it can be defined as the study of the genome and its products (including RNA and protein) as they relate to drug discovery and development.

Phenotype

Observable characteristics resulting from interaction between an organism’s genetic makeup and the environment.

Plasmid

A small circular form of DNA that carries certain genes and is capable of replicating independently in a host cell.

Plasmocyte

Lymphoid cell which synthesised and secretes immunoglobulins. They are deriving from the maturation of Lymphocytes B.

Polyclonal

Derived from different types of cells.

Polymerase chain reaction (PCR)

A method for repeatedly duplicating trace amounts of DNA in order to provide detectable quantities for analysis. PCR is frequently used for DNA fingerprinting (DNA profiling).

Polymorphism

The existence of two or more variants (alleles, phenotypes, DNA sequence variants, chromosomal structure variants) at significant frequencies in the population.

Polypeptide

Long chain of amino acids joined by peptide bonds.

Post-traductionnal modification

Modification of a protein after it has been synthesised via mRNA.

Prokaryote

An organism whose DNA is not enclosed within a nuclear membrane.

Promoter

A DNA sequence that is located in front of a gene and controls gene expression. Promoters are required for binding RNA polymerase to initiate transcription.

Prophage

Phage nucleic acid that is incorporated into the host’s chromosome but does not cause cell lysis.

Protein

A molecule composed of amino acids. There are many types of proteins, all carrying out a number of different function essential for cell growth.

Receptors

Cells or group of cells whose main function is the detection of certain stimuli.

Recombinant DNA (rDNA)

The DNA formed by combining segments of DNA from different types of organisms.

Replication

Reproduction or duplication, as of an exact copy of a strand of DNA.

Replicon

A segment of DNA that can replicate independently

Retrovirus

A virus that contains the enzyme reverse transcriptase. This enzyme converts the viral RNA into DNA, which can combine with the DNA of the host cell and produce more viral particles.

Ribonucleic acid (RNA)

Nucleic acid coming from the transcription of the DNA.

Sequencing

Decoding a strand of DNA or gene into the specific order of its nucleotides. This analysis can be done manually or with automated equipment.

Single-nucleotide polymorphism (SNP)

An SNP is a single base variation that occurs about every 1000 bases along 3 billion base pairs of the human genome.

Somatic cell gene therapy

Involves the insertion of genes into somatic cells for therapeutic purposes.

Somatic cells

Cells other than sex or germ cells.

Splicing

The removal of introns and joining of exons to form a continuous coding sequence in RNA.

Structural gene

A gene that codes for a protein, such as an enzyme.

Suppressor gene

A gene that can reverse the effect of a mutation in other genes.

Tissue culture

In vitro growth in nutrient medium of cells isolated from tissue.

Transcription

Synthesis of messenger(or any other) RNA on a DNA template.

Transduction

Transfer of genetic material from one cell to another by means of a virus or phage vector.

Transfection

Infection of a cell with nucleic acid from a virus, resulting in replication of the complete virus.

Transfer RNA (tRNA)

RNA molecules that carry amino acids to sites on ribosomes where proteins are synthesised.

Transformation

Change in the genetic structure of an organism by the incorporation of foreign DNA.

Transgenic organism

An organism formed by the insertion of foreign genetic material into the germ line cells of organisms. Recombinant DNA techniques are commonly used to produce transgenic organisms.

Translation

Process by which the information on a mRNA molecule is used to direct the synthesis of a protein.

Transposon

A segment of DNA that can move around and be inserted at several sites in bacterial DNA or in a phage, thus alerting the host’s DNA.

Wild type

The form of an organism that occurs most frequently in nature.

Zygote

A fertilised oocyte (first stage of embryo development).