Carcinogen. An agent capable of initiating development of malignant (cancerous) tumours.

65. Carcinogen. An agent capable of initiating development of malignant (cancerous) tumours.

66. Carrageenan. Sulphated cell-walled polysaccharide found in certain red algae. Contains re- peating sulphated disaccharides of galactose and anhydrogalactose.

67. Carrier. A matrix strategically placed within a bioreactor or cell-culture system to serve as a

PHARMACEUTICAL BIOTECHNOLOGY

68. Carbon Source. A source for non-metallic element carbon (C) e.g., as organic substances, sugars, corn-steep liquor, maltose, glucose, glucose-syrup, whey powder, molasses (containing 8–10% residual sucrose) etc., that are usually taken up and metabolized by organisms in culture media or by plant-tissue cultures.

69. Casein Hydrolysate (Edamin). A milk protein (casein) digestive product very much com- posed of amino acids (casamino acids) and other substances. The resulting complex (i.e., uni- dentified product) is sometimes used as an additive (0.02 – 2.10%) in nutrient solutions em- ployed in various culture media and plant tissue culture as a non-specific source of organic

nitrogen.

70. Cell Count. The number of cells per unit suspension volume or cellus weight. Tissue is treated with chromic acid (5-8%) or pectinase (0.25%) for upto 15 minutes normally followed by me- chanical dispersion, and subsequently the cell numbers are determined with the help of a

haemocytometer.

71. Cell Disrupter. A procedure employed to liberate the contents of cells.

72. Cell Hybridisation. The formation of synkaryons viable cell hybrids produced through cell fusion. These hybrids may be identifide by their enhanced chromosome number in compari- son to the parent cells and the possession of typical characters found in one or of the parent cells.

73. Cell Line. A cell line is permanently established culture which will proliferate indefinitely giving suitable fresh medium and space. The developmental history or descent through cell division is from a single original cell. Any deviation in the culture technique may favour one cell line over another.

74. Cell-Mediated Hypersensitivity. Delayed hypersensitivity reaction involving T lymphocytes, and taking place almost 24-72 hours after due exposure to the antigen.

75. Cell-Mediated Immunity. A highly specific acquired immunity involving T cells, primarily responsible for resistance to infectious diseases caused by certain bacteria and viruses that reproduce within the host cells.

76. Cell Number. The absolute number or approximation of the number of cells per unit area of a culture or medium volume.

77. Cell Selection. Selection within a group of genetically different cells, and usually involves competition between cells often under certain stress. The selection criteria may involve three main variants, namely : (a) cell viability ; (b) biochemical activity ; (c) another basis for choice. Normally, the selected cells or cell lines are carefully relocated to either fresh medium for continued selection process or duly exposed to an enhanced level of the stress agent. However, the ultimate aim is usually to regenerate plants from those select cells with a possibility that the plants may exhibit the specific traits selected for at the cellular level.

78. Cell Suspension. Cells and small aggregates of cells suspended in a liquid medium e.g., cell suspension cultures. Callus or explants derived from cell suspensions are transferred to liquid medium, and the cultures are subsequently agitated to a mechanical shaker. Importantly, the ensuing single cells as well as small cell clusters are employed for a number of purposes in plant tissue culture viz., single-cell cloning.

79. Cell Bank. A facility for preserving and keeping cells frozen at extremely low temperatures. These cells are used for investigating hereditary diseases, human aging, and cancer. Collection

GLOSSARY

Repository and the Aging Cell Repository) and at the Cornell Institute for Medical Research.

80. Cell Counter (Electronic). An electronic instrument employed to count blood cells, employ-

ing either an electrical resistance or an optical grating technique e.g., flow-cytometry.

81. Cell Cycle. The series of events that take place during the growth and development of a cell

e.g., meiosis and mitosis.

82. Cell Growth Cycle. The order of physical and biochemical events which take place during the growth of cells. In tissue-culture studies the cycle changes are divided into specific periods or phases, namely : (i) DNA synthesis (or S period) ; (ii) G 2 period (or gap) ; (c) M or mitotic

period ; and (d) G 1 period.

83. Cell-kill. In antineoplastic therapy, the number of malignant tumour cells destroyed by a treat- ment.

84. Cell Kinetics. The study of cells and their subsequent growth and division. Study of these factors has enormously led to much better understanding of cancer cells and has been found to

be useful in developing newer chemotherapeutic methods.

85. Cell Mass. In embryology, the mass of cells that develops into an organ or structure.

86. Cell Organelle. Any of the structures in the cytoplasm of a cell viz., mitochondria, endoplasmic reticulum, Golgi complex, ribosomes, lysosomes, and centriole.

87. Cell Sorting. A technique used to separate cells with a surface antigen from those without it.

88. Classical Competent Pathway. Series of reactions initiated by the formation of a complex between an antigen and an antibody which ultimately lead to the lysis of microbial cells or the enhanced ability of phagocytic blood cells to eliminate such cells.

89. Chimera (Chimaera). A plant or tissue composed of more than one kind of genetic tissue.

90. Chimeric Gene. An artificial gene produced by combining the DNA sequences from several different sources.

91. Chromatid. Single chromosome containing only one DNA complex.

92. Chromatins. The DNA-protein complex that constitutes a chromosome.

93. Chromosome. The deoxyribonucleic acid (DNA) bearing structure that carries the inheritable characteristics of an organism.

94. Chelate. A chemical compound (liquid) with which metal atoms may be combined in such a manner so as to prevent them (bivalent, trivalent metal ions) from precipitating out of solution, and thus rendering them unavailable to plants, such as : ethylenediamine tetraacetic acid (EDTA),

its disodium salt (Na -EDTA), which undergoes complexation to Fe 2+ 2 (ferrous ion)/Fe 3+ (ferric ion) present in nutrient solutions employed for plant tissue culture. The phenomenon is usually termed as chelation.

95. Chemotherapeutant. A chemical frequently employed to pretreat diseased source plants prior to excision or incorporation into the media to support certain specific therapeutic objective, for instance malachite green, virazole (ribavirin) are employed to eliminate completely the virus present in the meristem-tip culture. The phenomenon is known as chemotherapy.

96. Clone. A group of genetically identical cells or organisms descended asexually from a common ancestor. All cells in the clone have the same genetic material and are exact copies of the original.

97. Clonal Selection Theory. The theory accounts for exclusive antibody formation during foetal development wherein complete set of lymphocytes are developed. Each lymphocyte consisting

PHARMACEUTICAL BIOTECHNOLOGY

of the genetic information for initiating an immune response to a single specific antigen for which it possesses essentially only one type of receptor. Interestingly, the B cells that react with self-antigens during this specific period get destroyed eventually.

98. Complement. Group of proteins usually present in the plasma and tissue fluids that precipitate in antigen-antibody reactions leading to cell lysis.

99. Complement Fixation. The specific binding of complement of an antigen-antibody complex so that the complement is unavailable for subsequent reactions.

100. Complement Fixation Test (CFT). It measures the degree of complement fixation for the diagnostic purposes solely.

101. Complementary Base Pair. In DNA two strands are complementary e.g., G and C pairs via.

3 H-bonds ; A and T pairs via. 2 H-bonds ; in RNA, only A and U pairs are paired. 102. Complementary Sequences. Two sequences of nucleotides which have the capacity of base

pairing throughout their entire length. 103. Complementary Strands. Two single strands of DNA in which the ensuing nucleotide se-

quence is such that they will get bound by virtue of the base pairing throughout their length. 104. Complex Substance. A complicated and undefined substance ; as in the instance of certain

additive(s) to nutrient solutions used in plant-tissue culture, such as : protein hydrolysate, malt extract, yeast extract, endosperm obtained from corn or coconut, orange juice, tomato juice, and the like.

105. Complex-Mediated Hypersensitivity. Type-3 hypersensitivity, a reaction that invariably takes place in the event when an excess of antigens are produced in the course of a normal inflamma- tory response and antibody-antigen complement complexes are deposited in the tissues.