Galvanotropism See galvanotaxis

Gamete Specialized haploid cell produced by meiosis and involved in sexual reproduction. Male gametes are usually small and motile (spermatozoa), whereas female gametes (oocytes) are larger and non-motile. gametocyte A cell that divides to produce gametes. Also the sexual reproductive stage of the malaria parasite that develops within erythrocytes. gametogenesis Process leading to the production of gametes. gametophyte Haploid stage of life cycle of plants the major vegetative stage for simple...

Preface to the Third Edition

This resource, both on-line and, given the speed at which the discipline is evolving, to produce another in due course. Meanwhile we hope that people will find this edition useful and find it much easier, and quicker to search adjacent entries. We also hope that people will not hesitate to send new entries, suggest amendments and help in the evolution of this unusually interactive resource. The on-line Dictionary is to be found on In the preface to the first edition we commented that 'the...

Elegantin See disintegrin

Eleidin Clear substance found in stratum lucidum of skin, a keratin precursor. elementary bodies 1. Inclusion bodies within cells, often of virus particles, although this term is more common in the older literature. 2. Infectious extracellular form of Chlamydia, consisting of electron-dense nuclear material and a few ribosomes surrounded by a rigid trilaminar wall. Once taken up by cells, these reorganize into reticulate bodies. elephantiasis Lymphatic filariasis Enlargement of the limbs, or of...

Dermatophagoides pteronyssinus House dust

Antigens extracted from mites and their faeces are a common cause of allergy to house dust in W. European countries. Major allergen is Der p I, a cysteine peptidase. dermatophytes Fungi that can cause infections of the skin, hair, and nails due to their ability to utilize keratin. Examples are ringworm and athlete's foot. dermatopontin TRAMP A 22-kDa extracellular matrix (ECM) protein that interacts with other ECM components, especially decorin, and regulates ECM formation and collagen...

Cladogenesis See anagenesis

Cladogram A branching diagram (dendrogram) showing the relationships between groups of organisms determined by the methods of cladistics. clamp connection In many basidiomycete fungi a short lateral branch of a binucleate cell develops. This is the developing clamp connection. One of the nuclei migrates into it. Both nuclei then undergo simultaneous mitosis so that one end of the cell contains two daughter nuclei from each of the parental nuclei. The nucleus in the branch and the two nuclei are...

Androstenedione

Anaphase The stage of mitosis or meiosis beginning with the separation of sister chromatids (or homologous chromosomes) followed by their movement towards the poles of the spindle. anaphase-promoting complex Cyclosome An unusually complicated ubiquitin ligase, composed of 13 core subunits (total 1.5 MDa) and either of two loosely associated co-activators, Cdc20 and Cdhl, that is responsible for initiation of sister chromatid separation and the inactiva-tion of cyclin-dependent kinases. The...

Binucleate A cell that has two nuclei

Bioaccumulation Accumulation of substances in living organisms because the rate of intake exceeds the capacity to excrete or metabolize the substance. Organisms at the top of a food chain can accumulate considerable amounts of some substances, the most notorious of which was DDT. bioactivation Metabolic conversion of a xenobiotic substance to a more toxic or active derivative. bioassay An assay for the activity or potency of a substance that involves testing its activity on living material....

Gastrocoel See archenteron

Gastroparesis Disorder in which paralysis of the stomach muscles delays the passage of food through the stomach. Often associated with Type 1 diabetes. Gastropoda Class of the Phylum Mollusca snails, slugs, limpets and conches. gastrula Embryonic stage of an animal when gastrulation occurs follows blastula stage. gastrulation During embryonic development of most animals a complex and coordinated series of cellular movements occurs at the end of cleavage. The details of these movements,...

Borrel body See Bollinger bodies

Borrelia burgdorferi Spirochaete, responsible for Lyme disease. Can be isolated from midgut of ticks (Ixodes). bortezomib Velcade Small molecule drug, a modified dipeptidyl boronic acid, that inhibits the chymotypsin-like activity of the 26S proteosome used in treatment of multiple myeloma. Botox Proprietary name for Botulinum toxin type A, injected into the skin as a temporary treatment to make lines on the face less apparent. botrocetin Venom coagglutinin Lectin (22 kDa) from Bothrops...

Cyclizine hydrochloride An antiemetic antihistamine drug

Cyclo-oxygenase COX Enzyme complex present in most tissues that produces various prostaglandins and thromboxanes from arachidonic acid inhibited by aspirinlike drugs, probably accounting for their anti-inflammatory effects. Three isoforms are known COX-1, COX-2 and COX-3. cyclodextrins Cyclic polymers of six, seven or eight a-1,4-linked D-glucose residues. The toroidal structure allows them to act as hydrophilic carriers of hydrophobic molecules. cycloheximide Antibiotic (MW 281) isolated from...

Aplastic anaemia

Endocrine cells (chiefly G and D types) and a few parietal (oxyntic) cells. antrum 1. A cavity or chamber, especially in bone. 2. The lower third of the stomach which lies between the body of the stomach and the pyloric canal. 3. In the ovary, the fluid-filled space within the follicle. Antrycide Proprietary name for an antitrypanocidal drug used in veterinary practice. anucleolate Literally, having no nucleoli. An anucleolate mutant of Xenopus (viable when heterozygous) is used in nuclear...

Cobalamin Vitamin B12 See Table V1 cobra venom factor See C3

Cobratoxin a-Cobratoxin Polypeptide toxin (71 residues) from Naja kaouthia. One of the alpha-neurotoxins (curaremimetics), it binds to nicotinic acetylcholine receptors with high affinity. cocaine Drug of abuse and psychostimulant that acts to increase extra-neuronal dopamine in the midbrain by binding to the dopamine uptake transporter and hence inhibiting dopamine re-uptake at the plasma membrane. co-carcinogens Substances that, though not carcinogenic in their own right, potentiate the...

Benzamidine A potent inhibitor of serine endopeptidases such as thrombin and trypsin

Benzimidazole N,N' -Methenyl-o-Phenylenediamine Benzimidazole and its derivatives are used in organic synthesis and vermicides or fungicides. An example of benzimidazole class fungicides is benomyl. benzodiazepines Class of drugs that are anxiolytics or hypnotics, widely used in medical practice as CNS depressants. Enhance the inhibitory action of GABA by modulating GABA receptors. Diazepam (Valium) is commonly used for relieving anxiety, and nitrazepam (Mogadon) for inducing hypnosis....