bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcript Elongation and Termination
Authors: Richardson John P
Published: September 2006

The mechanism for elongation and termination of gene transcripts by bacterial RNA polymerases depends on the nucleotide addition reaction, transcript elongation rates, coupling transcription with translation, sequences signals for terminators and the roles of terminators and anti‐terminators in regulation of gene expression.
Translation Control by Proteins
Authors: Goldman Emanuel
Published: September 2006

Translation control by proteins refers to the process by which protein synthesis of specific products is regulated by external
trans
‐acting proteins, often by repression and sometimes autoregulatory on the messenger RNA encoding the very protein being synthesized, and also by activation in some systems.
Enzymes: Purification
Authors: Salem Jerome
Published: September 2006

Purification is the first and most critical step in the study of a protein or enzyme: most modern analytical techniques do not tolerate impurities and some also demand large amounts of material. Each protein is different, even homologues from different sources, and is likely to require a unique purification scheme.
Enzyme Activity: Allosteric Regulation
Authors: Traut Thomas
Published: September 2006

Cells can respond to changes in their environment by altering the flow through particular metabolic pathways. Such a change in any metabolic step is due to certain key enzymes that have the ability to alter their rate of activity. Such enzymes are defined as allosteric. The extent to which these enzymes adopt either the active conformation or the inactive conformation depends on their response to appropriate positive or negative signals. An easily measured feature of allosteric enzymes is the cooperativity that they show in a kinetic experiment.
Regulation by Covalent Modification
Authors: Martin Bruce L
Published: September 2006

Covalent modifications are enzyme‐catalysed alterations of synthesized proteins and include the addition or removal of chemical groups. Modifications can target a single type of amino acid or multiple amino acids and will change the chemical properties of the site. Consequences for the structure and functions of the protein modified are manifested, providing a sensitive method for cellular regulation.
Catalytic Antibodies
Authors: Gigant Benoît , Knossow Marcel
Published: September 2006

It is possible to elicit antibodies that catalyse a target reaction by raising them against stable molecules mimicking intermediate species on the chemical pathway from substrate to product. These artificial biocatalysts are closer to enzymes than any other enzyme mimic. Recent progress and new strategies bode well for the practical use of catalytic antibodies.
Transfer RNA
Authors: Goldman Emanuel
Published: September 2006

Transfer RNA is the class of molecules that decode the genetic code and link the coded information to their attached amino acids. These become constituents of the protein specified by the gene.
Regulatory RNA
Authors: Wagner E Gerhart H , Altuvia Shoshy , Nellen Wolfgang
Published: September 2006

Beyond their coding capacity, RNA molecules serve structural, catalytic and regulatory functions. The latter are elicited by RNA–RNA interactions (antisense‐target), frequently resulting in complex three‐dimensional structures, and by RNA–protein interactions. The numerous examples known to date probably present only a first glimpse at this expanding field.
Spliceosomal Machinery
Authors: Beggs Jean D
Published: September 2006

The spliceosomal machinery is the complex system of interacting protein and RNA splicing factors that mediate the removal of introns from nuclear premessenger RNAs. The spliceosome itself is a macromolecular complex composed of five small nuclear RNAs and approximately 100 proteins in which the splicing reactions occur.
Caps on Eukaryotic mRNAs
Authors: Furuichi Yasuhiro , Shatkin Aaron J
Published: September 2006

A 5′‐terminal cap is added to most eukaryotic cellular and viral pre‐mRNAs at an early stage of synthesis. Capping is essential and modulates several subsequent events including RNA splicing, translation and stability.
mRNA Turnover
Authors: Ross Jeff
Published: September 2006

mRNA turnover is the rate at which a mRNA is degraded intracellularly and is described in terms of mRNA half‐life, which is the time required to degrade 50% of the mRNA.
Immune System
Authors: Davies D Huw
Published: September 2006

The immune system comprises an interacting assemblage of cells and soluble molecules whose primary function is to remove invading microorganisms that cause damage to the body. An innate system, which responds to uniquely microbial structures, underlies an adaptive system mediated by antigen receptors on lymphocytes, which together trigger one or more different killing mechanisms according to whether the microbes live within or outside the cells of the body.
Immunological Discrimination Between Self and Nonself
Authors: Heinen Ernst
Published: September 2006

Self–nonself discrimination is ensured mainly by lymphocyte receptors during lymphopoiesis and immunopoiesis, but antigen presentation also plays a part. Whether caused by infection or by other factors, alterations of lymphocytes or of antigen presentation can alter self tolerance and trigger autoimmune reactions.
Antigen‐presenting Cells
Authors: Stagg Andrew J , Knight Stella C
Published: September 2006

Antigen‐presenting cells (APC) are able to acquire microbial and other antigens and display these antigens on their surface in a way that leads to activation of T and B lymphocytes, the major effector cells of the immune system. Different types of APC interact with different lymphocyte populations and stimulate distinct types of immune responses.
Kallikrein–Kinin System
Authors: Regoli Domenico , Calo Girolamo , Gobeil Fernand
Published: September 2006

Two similar proteolytic cascades lead to release of bradykinin and lysbradykinin in tissues; these peptides act as autocoids, the first favouring blood clotting and endothelial protection, the second by initiating and maintaining tissue reactions to noxious stimuli. Kinin biological actions are mediated by two different receptor types, the constitutive B2which promotes initial reactions and the inducible B1which may later maintain mechanisms of defence and repair.
Antibodies
Authors: Zouali Moncef
Published: September 2006

Antigens are antigen‐reactive proteins, designated immunoglobulins, present in the plasma and in extracellular fluids. They bind their nominal antigens with exquisite specificity and potentially neutralize their harmful effects.
Antibody Function
Authors: Lucas Alexander H
Published: September 2006

Antibodies are members of the immunoglobulin family, and they comprise a principal component of the adaptive humoral immune response to foreign antigenic stimuli. Antibodies protect against infectious diseases by specifically recognizing a large universe of antigens and by mediating biological effector mechanisms, in concert with cells and other molecules, to neutralize and eliminate infectious agents and their products.
B
Lymphocytes: Receptors
Authors: Kurosaki Tomohiro , Takata Minoru
Published: September 2006

The B‐cell receptor (BCR) is a complex of integral membrane proteins which is expressed on the cell surface of B lymphocytes. The BCR directly binds and recognizes an antigen, leading to signal transduction and activation of B lymphocytes.
T‐cell Receptors
Authors: Bonneville Marc , Saulquin Xavier
Published: September 2006

Antigen recognition by T lymphocytes is achieved via α/β or γ/δ T‐cell receptors, which are both produced through somatic rearrangement of gene segments. Upon their engagement by antigens, T‐cell receptors trigger a complex sequence of events that ultimately lead to T‐cell activation.
Secondary Metabolites: Killing Pathogens
Authors: Walton Jonathan D
Published: September 2006

Plants produce many antimicrobial secondary metabolites. Two major classes with a demonstrated or proposed role in resistance to plant pathogens are phytoanticipins, or preformed inhibitors, which are present constitutively in plants, and phytoalexins, which are synthesized only in response to pathogen attack. Available evidence is consistent with both phytoanticipins and phytoalexins being important in defence in some disease interactions.
Immunological Accessory Molecules
Authors: Croft Michael , Gramaglia Irene , Cooper David
Published: September 2006

Immunological accessory molecules may be loosely defined as proteins present on the surface of immune cells which can modulate, in a positive or negative fashion, the ability of the cell to perform one or several functions. As such they can be viewed as critical to the success or failure of controlling an infection.
Immunological Adhesion and Homing Molecules
Authors: von Andrian Ulrich H
Published: September 2006

Leucocytes must interact with other cells and extracellular matrix molecules to migrate from the bloodstream to lymphoid and nonlymphoid tissues, to detect and respond to antigen, and to exert immune functions. Adhesion and homing molecules on the surface of leucocytes and interacting cells provide mechanical stability and contribute to the specificity of such interactions.
Immunoglobulin Superfamily
Authors: Natarajan Kannan , Mage Michael G , Margulies David H
Published: September 2006

The immunoglobulin superfamily (IgSF) consists of a group of proteins that exploit the structural robustness and fundamental stability of the immunoglobulin fold for a wide assortment of functions across a broad span of evolutionary time, extending from microorganisms to humans. Although the best understood activities of IgSF members are related to immunological recognition, a number of related molecules participate in developmental and homeostatic phenomena. Manipulation of the IgSF by recombinant gene technology offers
in vitro
approaches to increase the available diversity of novel structures for almost limitless functions.
Immunological Cytotoxic Factors
Authors: Froelich Christopher J
Published: September 2006

The immune system has evolved a variety of strategies to protect the host from the detrimental effects of pathogens and tumour cells. The beneficial outcome is an apoptotic death for the offending cell and a lytic demise for the invading pathogen.
Interleukins
Authors: Mire‐Sluis Anthony R
Published: September 2006

The interleukins are a group of proteins that have been classified specifically by a designated nomenclature committee of the International Union of Immunological Societies/World Health Organization. These proteins are derived, mainly, from white blood cells and act on white cells, although these criteria are not necessarily exclusive of other cell sources and activities. Interleukins, amongst other proteins, maintain the haematopoietic and immune systems, and control their functions.
Chemokines
Authors: Horuk Richard
Published: September 2006

Chemokines (from
chemo
attractant cyto
kines
) are a family of polypeptides that direct the migration of leucocytes toward a site of infection. They play a major role in autoimmune disease and chemokine receptors have recently been found to mediate HIV‐1 fusion.
Venoms
Authors: Silva W Dias da , Kipnis Thereza L
Published: September 2006

Animal venoms contain highly toxic components that cause inflammation and tissue destruction at the point of contact or in the region of a sting or bite. General symptoms are mediated by toxins including activators or inactivators of blood clots and complement systems, cytotoxins directed to a variety of target cells and neurotoxins.
Infection: Immunological Barriers
Authors: Whitton J Lindsay
Published: September 2006

Microorganisms can infect a host through various portals of entry. The host attempts to counter microbial infection and dissemination using many physical, chemical and immunological weapons.
Mucosal Surfaces: Immunological Protection
Authors: Ponda Prashant P , Mayer Lloyd
Published: September 2006

The mucosal immune system serves to protect its host from a variety of pathogens while simultaneously allowing for tolerance under normal circumstances to prevent inflammatory disease.
Inflammation: Acute
Authors: Villarreal G , Zagorski J , Wahl SM
Published: September 2006

Inflammation represents the response of a vascularized tissue to injury. Inflammation and repair are essential to maintain tissue integrity.
Inflammation: Chronic
Authors: Wakefield Denis , Kumar Rakesh K
Published: September 2006

Chronic inflammation may result from failure to eliminate an acute inflammatory irritant, from an autoimmune response to a self antigen, or may be caused by an innately chronic irritant of low intensity that persists. It is characterized by simultaneous inflammation and repair, with recruitment and activation of macrophages, lymphocytes and other cells triggered by the coordinated action of cytokines and growth factors.
Immune Responses: Primary and Secondary
Authors: James Keith
Published: September 2006

Immune responses to antigens may be categorized as primary and secondary responses. The primary immune response of the body to antigen occurs on the first occasion it is encountered. The secondary response is that observed following a second or subsequent encounter with the same antigen.
Antigenic Competition
Authors: Hunt Jacqueline D , Brown Lorena E , Jackson David C
Published: September 2006

Antigenic competition is the name given to the phenomenon in which inhibition or diminution of the immune response to one antigen or determinant occurs following its administration in the presence of another antigen or determinant.
Lymphocytes: Precursor Frequencies
Authors: Zwickey Heather L , Potter Terry A
Published: September 2006

Precursor frequency experiments use limiting dilution analysis to provide an estimate of the number of lymphocytes capable of responding to a particular antigen. They can be used to measure and enhance the frequency of antigen‐specific lymphocytes.
Immunological Tolerance: Mechanisms
Authors: Zouali Moncef
Published: September 2006

Immunological tolerance refers to a reduction or complete inhibition of the ability of an individual to mount a specific immune response upon immunization.
Immunological Memory
Authors: Zanetti Maurizio , Croft Michael
Published: September 2006

Immunological memory is defined functionally as the event that occurs when the immunologically experienced individual re‐encounters antigen through infection or immunization, and as a result develops a greater and faster response than after the first encounter.
Idiotype Network
Authors: Fehr Thomas , Caspar Clemens B
Published: September 2006

The idiotype network is an immunological concept which describes the idiotype‐specific interaction of antibodies leading to suppression of certain idiotypes or to induction of autoimmunity depending on the experimental conditions.
Neonatal Immunity
Authors: Reen Denis J
Published: September 2006

Neonatal immunity involves the factors that determine the newborn's immunocompetency during the first 28 days of life. These factors include cellular and molecular components of the neonate's own innate and adaptive immune system as well as components acquired transplacentally and via breast milk feeding from the mother.
Bacterial Capsules and Evasion of Immune Responses
Authors: Merino Susana , Tomás Juan M
Published: September 2006

Bacterial capsules are one of the most external structures on the bacterial surface. Different Gram‐negative and Gram‐positive capsules contribute to the bacterial resistance of host immune responses.
Gene Expression: Decoding and Accuracy
Authors: Nierhaus Knud H
Published: September 2006

During decoding of the genetic message, the ribosome must select the correct substrate, a ternary complex aminoacyl‐tRNA–EF‐Tu–GTP, from a large number of almost identical complexes. The problem is solved by dividing substrate binding into two steps: (1) decoding, which is mainly restricted to codon–anticodon interactions, and (2) interactions between substrate and ribosome, which are mainly responsible for high‐affinity binding rather than for selectivity.
Peptidyl Transfer on the Ribosome
Authors: Nierhaus Knud H , Stelzl Ulrich
Published: September 2006

Formation of the peptide bond is the central enzymatic activity of ribosomes. The active centre resides on the large ribosomal subunit, containing 23S rRNA (domain V) and probably also ribosomal proteins (e.g. L2).
Microorganisms: Applications in Molecular Biology
Authors: Keeney Jill B
Published: September 2006

Microorganisms, most notably yeast and bacteria, are used in research and industry for cloning genes, replicating DNA and producing purified proteins. Yeast, in particular, is widely used as a model organism for studying a variety of cell functions.
Ligation: Theory and Practice
Authors: Chandrasegaran Srinivasan , Reddy Sekhar PM
Published: September 2006

Adenosine triphosphate and NAD
+
‐dependent DNA ligases catalyse the formation of phosphodiester bonds between juxtaposed 3′‐hydroxyl group and 5′ phosphate termini in duplex DNA. Ligase chain reaction, which utilizes a thermostable ligase to both amplify DNA and discriminate a single‐base substitution in target DNA, is a powerful
in vitro
method that complements polymerase chain reaction that has revolutionized DNA diagnostics.
Protein Domain Fusion
Authors: Sadowski Ivan
Published: September 2006

Proteins are composed of multiple functional and structural domains. Using recombinant DNA techniques, it is possible to create chimaeric proteins with novel functions for research or biotechnology purposes, and for the development of novel therapies.
Genetic Engineering: Reporter Genes
Authors: Lawler Joseph F , Boeke Jef D
Published: September 2006

Reporter genes are easily measured surrogates for a molecule of interest.
Phage Display Technologies
Authors: Stricker Nicole , Li Min
Published: September 2006

Phage display is a method that uses bacterial virus (phage) as a vehicle to express diverse protein or peptide sequences as part of the phage coat protein by cloning deoxyribonucleic acid (DNA) fragments in frame with phage coat protein genes. Upon viral infection, the expressed peptides are displayed on the surface of the viral particle. Depending on the DNA fragments cloned,
phage
display allows for expression of either short peptides or large proteins, such as immunoglobulin, on the viral surface.
Protein Production for Biotechnology
Authors: Shi Qinwei , Ling Michael Mingfu , Yang Tracy
Published: September 2006

Recombinant proteins can be synthesized and prepared at lower manufacturing cost and in higher purity compared to their native counterparts. Proteins can be produced by gene expression methods using different expression systems ranging from bacteria to transgenic animals.
Ribozymes in Biotechnology
Authors: Ruffner Duane E
Published: September 2006

Ribozymes are RNA molecules that catalyse the cleavage and/or ligation of other RNA molecules. This capacity of ribozymes has therapeutic application for the inactivation of deleterious genes and the repair of mutated genes involved in many disease states.
Transgenic Animals
Authors: Houdebine Louis Marie
Published: September 2006

Transgenesis implies that a foreign DNA fragment is introduced into the genome of a multicellular organism and transmitted to progeny. Transgenesis therefore differs from gene transfer into cultured cells (transfection) or into the somatic cells of a patient (gene therapy).
Knockout and Knock‐in Animals
Authors: Mansouri Ahmed
Published: September 2006

The inactivation of a gene (knockout) or the insertion of a coding sequence into a gene of interest (knock‐in) provides genetically modified animals for the analysis of genetic circuits in developmental biology and for use as models for human disease.
Transgenic Plants
Authors: Crouzet Philippe , Hohn Barbara
Published: September 2006

Transgenic plants contain genetic material (their own, foreign or artificial) stably integrated into their genome that has been introduced by methods other than classical breeding and that is passed on to successive generations.
Human Gene Therapy
Authors: Ioannou Panos A
Published: September 2006

Human gene therapy is the treatment of human diseases with DNA
fragments comprising whole genes or parts of genes.
Northern Blotting and RNA Detection
Authors: Zimmers‐Koniaris Teresa
Published: September 2006

Northern blotting is a means of identifying a certain RNA species in a complex mixture of RNA. Commonly used to evaluate qualitatively and quantitatively the expression of a gene, Northern blotting involves isolation of RNA, size fractionation of the denatured RNA through gel electrophoresis, transfer of the separated RNA to a membrane, hybridization with a specific probe, and detection.
Polymerase Chain Reaction (PCR)
Authors: Metzker Michael L , Caskey Thomas C
Published: September 2006

PCR is a rapid
in vitro
DNA synthesis process, which can amplify up to a billion copies of a given nucleic acid target.It has been extensively applied for the identification, detection and diagnosis of genetic and infectious disease.
Mutagenesis: Site‐specific
Authors: El‐Gewely M Raafat , Fenton Chris , Salomonsen Laila J , Xu Hao
Published: September 2006

Site‐specific mutagenesis techniques are aimed at the precise substitution, insertion or deletion of any coding sequencein vitro. These techniques are revolutionizing our understanding of the genetic and molecular mechanisms in several biological systems, which could lead to the development of new therapeutics and also improved agriculture.
Retroviruses in Human Gene Therapy
Authors: Pedersen Finn Skou , Duch Mogens
Published: September 2006

A retrovirus‐based gene transfer system consists of two components: the transfer vector, which harbours a foreign gene linked to elements needed for retroviral replication, and the packaging cell, which supplies the necessary retroviral proteins for transfer of the vector through a single round of viral replication. Most clinical protocols for gene therapy or gene marking using retroviral vectors are based upon gene transfer
ex vivo
followed by reimplantation of the target cells into the body.
Avian Influenza Viruses
Authors: Perdue Michael L
Published: September 2006

Avian influenza viruses
comprise scores of antigenic subtypes in the type A orthomyxovirus family. They are found most prominently in migratory waterfowl and shorebirds and are sporadically transmitted to other avian and mammalian species. The consequences of such transmissions can range from a subclinical infection, which may result in transfer of avian virus genes into the circulating influenza gene pool, to a highly infectious and lethal respiratory disease.
Baculoviruses
Authors: Guarino Linda
Published: September 2006

Baculoviruses are large, complex DNA viruses that infect arthropods. Although best known for their use as eukaryotic expression vectors, they are also important as biological control agents, pests of sericulture, and as basic research models.
Orbiviruses and
Bluetongue virus
Authors: Mertens Peter
Published: September 2006

Bluetongue virus
(BTV) is the type species of the genus
Orbivirus
within the family
Reoviridae
, a large family of double‐stranded ribonucleic acid (dsRNA) viruses. BTV causes the disease ‘bluetongue’ in sheep, although the virus also infects cattle, deer, camels and goats.
Canine Distemper Virus
Authors: Harder Timm C , Osterhaus Albert DME
Published: September 2006

Canine distemper virus is a highly contagious organism causing distemper in dogs and several wildlife carnivore species. It is closely related to Measles virus, which infects humans.
Coltiviruses
Authors: Guirakhoo Farshad , Monath Thomas P
Published: September 2006

Coltivirus
(family
Reoviridae
) is the genus of viruses that consist of 12 segments of double‐stranded RNA.
Nidoviruses
Authors: Ziebuhr John , Siddell Stuart
Published: September 2006

Nidoviruses are a group of positive‐sense, enveloped RNA viruses that infect a variety of vertebrates. They are associated with both overt and asymptomatic diseases in their natural hosts.
Cytomegaloviruses
Authors: Chatterjee Archana , Harrison Christopher J
Published: September 2006

The cytomegaloviruses are a common group of viruses that are widely distributed in the animal kingdom, have a complex biology and, in humans, pose a significant threat to immunocompromised individuals and the fetuses of nonimmune mothers.
Hantaviruses
Authors: Feldmann Heinz
Published: September 2006

Hantaviruses comprise a genus of the
Bunyaviridae
family and naturally infect wild rodents without causing clinical symptoms. When acquired by inhalation of aerosolized rodent excreta, hantaviruses can cause life‐threatening diseases in humans, such as haemorrhagic fever with renal syndrome in Asia and Europe and hantavirus pulmonary syndrome in the Americas.
Hepatitis A Virus
Authors: Robertson Betty H , Bell Beth P
Published: September 2006

Hepatitis A virus
is one of the five major viruses that replicate in, and cause inflammation of, the liver. A picornavirus spread by faecal–oral contact, it accounts for over 90% of viral hepatitis infections worldwide.
Hepatitis Delta Virus
Authors: Taylor John M
Published: September 2006

Several animal viruses are important causes of acute and chronic infections of the human liver. Hepatitis delta virus is a most unusual agent that is found only in association with Hepatitis B virus.
Hepatitis
E
Virus
Authors: Kamili Saleem , Krawczynski Krzysztof
Published: September 2006

Hepatitis E virus
is a nonenveloped RNA virus that is responsible for large epidemics and sporadic cases of self‐limiting, enterically transmitted, acute viral hepatitis in developing countries.
Lassa Fever Virus
Authors: Demby Austin
Published: September 2006

Lassa virus
originates from West Africa where it is primarily a virus of the rodent,
Mastomys
spp. Human infection is through contact with infected rodents or infected humans and ranges from a mild asymptomatic infection to a life‐threatening illness involving severe haemorrhage.
Nucleases
Authors: Kushner Sidney R
Published: September 2006

While the genetic information encoded in DNA and RNA molecules is directly related to the order of the purine and pyrimidine bases, it is the sugar–phosphate backbone that provides the glue that keeps these molecules intact. It is the function of nucleases to break the stable phosphodiester bonds between the sugar moieties when necessary. Nucleases participate in almost all biological reactions involving either RNA or DNA.
Topoisomerases
Authors: Bates Andrew D
Published: September 2006

Topoisomerases are enzymes that interconvert different topological states of DNA, such as levels of supercoiling, catenanes (links) and knots. They are vital to all DNA‐related processes and are the targets for a number of antibacterial and anticancer agents.
Supercoiled DNA: Structure
Authors: Bowater Richard Peter
Published: September 2006

Supercoiling is introduced into DNA molecules when the double helix is twisted around its own axis in three‐dimensional space. Generally, DNA molecules are negatively supercoiled inside cells, although the level of supercoiling is not equal throughout the genome and many supercoils may be constrained by bound proteins. Introduction of supercoiling into DNA increases its free energy and influences DNA metabolism by promoting or hindering specific enzymatic processes.
Eukaryotic DNA Polymerases
Authors: Cotterill Sue , Kearsey Stephen
Published: September 2006

DNA is replicated and repaired by a family of enzymes called DNA polymerases. Eukaryotic cells have a diversity of these enzymes that, while sharing a common biochemical activity, are specialized for particular roles.
DNA Helicases
Authors: Egelman Edward H
Published: September 2006

Helicases are proteins that use the energy of adenosine triphosphate (ATP) hydrolysis to open double‐stranded DNA, RNA or RNA–DNA hybrids into two single strands. DNA helicases provide single‐stranded DNA as templates for the DNA polymerase and are essential for replication.
Eukaryotic Replication Protein
A
Authors: Wold Marc S
Published: September 2006

Replication protein A (RPA) is a single‐stranded DNA‐binding protein that is essential for many processes in eukaryotic cells. It binds to single‐stranded DNA with high affinity and low specificity, and interacts specifically with a number of proteins. Both these activities are required for DNA replication, DNA repair and recombination.
Polymerase Processivity: Measurement and Mechanisms
Authors: Bloom Linda B , Goodman Myron F
Published: September 2006

The processivity of DNA synthesis by a DNA polymerase is defined as the number of nucleotides that a polymerase can incorporate into DNA during a single template‐binding event, before dissociating from a DNA template. The overall efficiency of DNA synthesis increases when the processivity of a polymerase increases.
DNA
Polymerase Fidelity Mechanisms
Authors: Fygenson Deborah Kuchnir , Goodman Myron F
Published: September 2006

DNA polymerase is a protein that catalyses the polymerization of one strand of DNA, called the primer strand, based on the sequence in another strand, called the template strand. Fidelity in this process refers to the ability of the polymerase to avoid or to correct errors in the newly synthesized strand.
Prokaryotic Replication Origins: Structure and Function in the Initiation ofDNAReplication
Authors: Messer Walter
Published: September 2006

Replication origins arecis‐acting sequences of a few hundred base pairs (bp) required for the replication of adjacent DNA. Their function is recognition of the correct start site and assembly of replication forks at this site.
DNA Ligases
Authors: Shuman Stewart , Gumport Richard I
Published: September 2006

DNA ligases are essential enzymes that catalyse the formation of a phosphodiester bond at a discontinuity in the deoxyribose phosphate backbone of duplex DNA.
Site‐specific Recombination
Authors: Segall Anca
Published: September 2006

Site‐specific recombination is defined as the rearrangement of two DNA partner molecules by specific enzymes performing recombination at their cognate pairs of sequences or target sites. Site‐specific recombination, in contrast to homologous recombination, requires very little DNA homology between partner DNA molecules, is RecA‐independent, and does not involve DNA replication at any stage.
Site‐specific Recombination: Uses in Biotechnology
Authors: Hoess Ronald H
Published: September 2006

Site‐specific recombination has become an important tool for manipulating DNA both in vitro and in vivo. It has found widespread use in controlling gene expression in transgenic plants and animals.
Evolutionary Developmental Biology: Developmental and Genetic Mechanisms of Evolutionary Change
Authors: Bolker Jessica A
Published: September 2006

Phenotypic evolution is based on developmental change. Understanding the evolutionary role of developmental and genetic mechanisms requires comparative and experimental analyses of the complex networks that regulate development.
Evolutionary Developmental Biology: Gene Duplication, Divergence and Co‐option
Authors: Ohno† Susumo , Holmquist Gerald P
Published: September 2006

The eukaryotic genome appears to have arisen by duplication of ancestral genomes and ancestral genes.
Evolutionary Developmental Biology: Developmental Constraint
Authors: Arthur Wallace
Published: September 2006

Developmental constraint is a bias against the production of certain phenotypes. The array of organismic forms found in nature results from an interplay between developmental constraint and natural selection.
Cleavage and Gastrulation in Mouse Embryos
Authors: Wild Arthur E , Fleming Tom P
Published: September 2006

Cleavage of the fertilized egg is the beginning of a developmental programme that leads to formation of the blastocyst which, after implantation, gives rise to the embryonic and extraembryonic lineages of the conceptus. Gastrulation results in the formation and segregation of the three germ layers and the establishment of the basic body plan of the developing fetus.
Cleavage and Gastrulation in
Drosophila
Embryos
Authors: Tram Uyen , Riggs Blake , Sullivan William
Published: September 2006

The cytoskeleton guides early embryogenesis in
Drosophila
, which is characterized by a series of rapid synchronous syncytial nuclear divisions that occur in the absence of cytokinesis. Following these divisions, individual cells are produced in a process called cellularization, and these cells are rearranged during the process of gastrulation to produce an embryo composed of three primordial tissue layers.
Cleavage and Gastrulation in
Xenopus laevis
Embryos
Authors: Elinson Richard P
Published: September 2006

The
Xenopus laevis
egg contains an asymmetric distribution of molecules, which are parcelled out to cells during cleavage. The different cells interact with each other and rearrange themselves during gastrulation to produce the tissues and organs of the embryo in their proper position.
Cleavage and Gastrulation in Avian Embryos
Authors: Stern Claudio D
Published: September 2006

Avian embryos differ from those of other vertebrates in several respects – among them, they have a large mass of yolk, the cells initially divide meroblastically, and the embryo has great ability to regulate until very late stages of development. After about 20 000 cells have been generated, gastrulation begins. This process establishes the three axes of the future embryo (head–tail, dorsoventral and left–right), and many cell fates become fixed.
Marburg virus
Authors: Feldmann Heinz , Klenk Hans‐Dieter
Published: September 2006

Marburg virus is a typical emerging virus that causes severe haemorrhagic fever in humans, with high case‐fatality rates.
Parainfluenza Viruses
Authors: Takimoto Toru
Published: September 2006

Parainfluenza viruses are enveloped viruses that contain nonsegmented negative‐strand genomic RNA. These viruses are one of the greatest single causes of respiratory tract infections.
Picornaviruses
Authors: Rowlands David J
Published: September 2006

The name of this family of viruses is derived from
pico
, the Latin for small, and RNA, denoting the chemical nature of the genome. They are among the smallest pathogens of vertebrates and are responsible for many important diseases in humans and animals.
Simian Retroviruses
Authors: Novembre Francis J
Published: September 2006

Simian retroviruses are enveloped viruses that contain a duplex RNA core. In general, viruses found in nonhuman primates constitute the closest relatives to human viruses, therefore a knowledge of these viruses is important for an understanding of their human counterparts, which induce significant morbidity and mortality.
Regeneration Model Systems: Invertebrate Epimorphic
Authors: Baguñà Jaume
Published: September 2006

To different extents, some invertebrates retain the ability to replace lost parts after asexual reproduction, predation or experimental manipulation. When new parts are formed from a mass of undifferentiated cells (the blastema), accumulated below the wound, this process is known as epimorphic regeneration.
Regeneration in Hydra
Authors: Galliot Brigitte
Published: September 2006

Hydra have a remarkable ability to regenerate after bisection or dissociation. Hydra regeneration offers a unique way to investigate ancestral molecular mechanisms leading to the establishment of organizer activity during animal development.
Regeneration of the Urodele Limb
Authors: Stocum David L
Published: September 2006

Urodele limbs regenerate via a blastema of progenitor cells derived from differentiated limb cells by a process of dedifferentiation. The blastema grows by mitosis of the progenitor cells under the influence of factors supplied by the wound epidermis and nerves, and is patterned into the new limb structures by molecular interactions between blastema cells.
Regeneration of the Vertebrate Tail
Authors: Ferretti Patrizia
Published: September 2006

Some vertebrates can regenerate their tail. This complex phenomenon is observed only in tails that contain the spinal cord. The spinal cord provides neural progenitor cells from which a new cord will form and in urodeles has a key role in differentiation and morphogenesis of other tail tissues.
Regeneration of the Vertebrate Lens and Other Eye Structures
Authors: Tsonis Panagiotis A
Published: September 2006

Some vertebrates, especially amphibians, can regenerate the lens after lentectomy. Other structures, such as retina, can also be regenerated. The regeneration process is initiated by the pigment epithelial cells which can transdifferentiate to lens or retina. While a gene responsible for such events is not known, evidence has mounted implicating Hox genes and fibroblast growth factors as key regulators.
Regeneration: Growth Factors in Limb Regeneration
Authors: Crawford Karen
Published: September 2006

Different tissues and growth factors permit and direct limb patterning at the cellular and molecular level during regeneration in amphibians.
Regeneration of Muscle
Authors: Carlson Bruce M
Published: September 2006

Muscle regeneration is the process by which damaged skeletal, smooth or cardiac muscle undergoes biological repair. The degree of success of the regenerative process depends upon a variety of intrinsic and environmental factors.
Regeneration of Bone
Authors: Neufeld Daniel A , Mohammad Khalid
Published: September 2006

The term bone regeneration is used either to describe bone repair or, more accurately, to describe bone formation in sites at which bone would not normally be expected to reform such as avulsion or amputation. Induced regeneration of bone is becoming one of the major success stories of biomedical research.
Regeneration of Liver
Authors: Fausto Nelson
Published: September 2006

One of the most fascinating features of the liver is that it has the capacity to regulate its own growth and mass. The hepatocyte, the main cellular component of the liver, is a metabolically active cell that does not actively replicate in the normal liver. Yet hepatocytes readily proliferate in response to a deficit in tissue mass or cells. Such conditions occur after surgical removal of portions of the liver (partial hepatectomy) or hepatocyte death caused by chemical injury or viruses. The growth response triggered by these conditions is known as liver regeneration.
Regeneration of Nervous Tissue
Authors: Gilbert Ryan J , Bellamkonda Ravi V
Published: September 2006

Deficits of the nervous system can be classified into two categories: ‘biochemical’, where replacement of a neurotransmitter like dopamine to a large measure corrects most Parkinsonian motor symptoms, and ‘networking’ deficits, where the connections between two sets of neurons or neurons and muscles are interrupted due to trauma or tumour resection. Various strategies are being investigated in an attempt to repair such deficits through regeneration of the nervous tissue.
Regeneration: Principles
Authors: Dinsmore Charles E
Published: September 2006

Biological regeneration, a fundamental capacity of all living things, includes processes ranging from the constitutive turnover of cellular components to the extraordinary ability of bisected hydra to become two structurally complete individuals or of salamanders to replace amputated limbs and tails. While historical debate over the nature of regeneration relied largely on its superficial similarity to embryonic development, advances in molecular biology and developmental genetics have now demonstrated a striking concordance between development and regeneration that reaches across phyla.
Agglutination Techniques for Detecting Antigen–Antibody Reactions
Authors: Price Christopher P
Published: September 2006

The agglutination reaction reflects multiple reactions that take place between macromolecules to form a complex, which may involve antigen–antibody interaction and which, through colloidal instability, may lead to precipitation. The formation of this complex leads to an increase in light scattering, which can be used to quantify one of the species participating in the reaction.
Antibody Synthesis in Vitro
Authors: Martínez Paz , Iborra Antoni
Published: September 2006

Several strategies are used to provide immortalized monoclonal antibody‐secreting B cells, and antibodies by recombinant deoxyribonucleic acid (DNA) technology. Monoclonal antibodies are good specific reagents to recognize any chemical structure. High concentrations of monoclonal antibodies can be obtained and used in diagnostics and human therapy.
Antigen–Antibody Binding
Authors: Kumagai Izumi , Tsumoto Kouhei
Published: September 2006

Antibodies are a family of glycoproteins that bind specifically to foreign molecules (antigens). The binding between antibodies and antigens has high specificity and affinity resulting from various structural and energetic aspects.
B
Lymphocytes
Authors: Bondada Subbarao , Chelvarajan Ralph L
Published: September 2006

B (bone marrow‐derived) lymphocytes are antibody‐producing cells in the body. Antibody production is initiated upon recognition of antigen via a specific immunoglobulin receptor, and reception of growth and differentiation signals. B lymphocytes are also important for activation of helper T lymphocytes and are integral for the memory component of the immune response.
Cells of the Immune System
Authors: Todd Ian
Published: September 2006

A variety of cell types are important components of the immune system. They constitute some of the body's main defences against infection.
Cytokine Assays
Authors: Whiteside Theresa L
Published: September 2006

Cytokines are low‐molecular‐weight mediators of cellular interactions. Their role in health and disease provides a key to the physiological importance of cytokines in cell‐to‐cell communication. In addition, changes in cytokine profiles may serve as indicators of pathological conditions associated with disease.
Immune Response: Regulation
Authors: Lukic Miodrag L , Lukic Aleksandra M
Published: September 2006

Early events in an immune response may determine the outcome of immunogenic stimulus, and molecules produced as part of an immune response ‐ such as cytokines and antibodies ‐ can feed back into, suppress or promote the response. Both under‐ and overreaction to antigens may be deleterious, so the immune system requires control mechanisms at different levels so as to provide an optimal immune response at all times.
Immunoassay
Authors: Price Christopher P
Published: September 2006

An immunoassay is a quantitative analytical technique that depends on the unique features of the reaction between an antigen and its complementary antibody to achieve specificity for the analyte of interest.
Immunoelectrophoresis
Authors: Kaplan Irina V , Levinson Stanley S
Published: September 2006

Immunoelectrophoresis a two‐stage process: electrophoresis is conducted in the first stage and immunoprecipitation using antibodies against specific proteins in the second stage. Resolution is improved by staining the proteins. The technique is widely used to identify monoclonal immunoglobulins (M‐components) in serum and urine.
Hypersensitivity: Immune Complex Mediated (Type III)
Authors: Eggleton Paul
Published: September 2006

An immune response in the form of antibody production against a foreign substance is often mounted to remove any detrimental antigen from the host. In type III hypersensitivity, overproduction of immunoglobulins IgG and IgM to a particular antigen can lead to the formation of excessive amounts of immune complexes. This in turn may trigger classical complement activation, leading to overproduction of other inflammatory mediators and activation of phagocytes culminating in tissue damage.
Secondary Induction: Overview
Authors: Saxén Lauri
Published: September 2006

Secondary induction is the tissue interaction governing cell differentiation and morphogenesis throughout embryonic development.
Epithelial‐Mesenchymal Interactions
Authors: Kratochwil Klaus
Published: September 2006

Epithelial‐mesenchymal organs develop through sequential and reciprocal interaction of the two tissues. A limited set of signalling factors mediates this interaction in a variety of organ systems.
Lens Induction
Authors: Kondoh Hisato
Published: September 2006

Lens cells differentiate from embryonic ectoderm by inductive influence of the retina primordium: this has been a paradigm of embryonic tissue induction. The application of modern techniques for manipulating embryonic tissues and genes, and the recent discovery of transcriptional regulators involved in lens development have thrown light on the molecular events governing the process of lens induction.
Tooth Induction
Authors: Thesleff Irma , Nieminen Pekka
Published: September 2006

The development of teeth is regulated by inductive tissue interactions of ectoderm and neural crest‐derived mesenchyme. The molecular basis of these interactions is currently being investigated.
Gonadal Induction
Authors: Koopman Peter
Published: September 2006

The determination of sex in the embryo is dependent on whether
testes or ovaries develop from the primordial gonads. This decision is in turn
controlled by the function of a gene,
SRY
, found on the Y chromosome
in mammals.
Apoptosis: Molecular Mechanisms
Authors: Wu Min , Ding Han‐Fei , Fisher David E
Published: September 2006

Apoptosis is an intrinsic cell‐suicide programme which ensures proper development by maintaining tissue homeostasis and safeguarding the organism through the elimination of unwanted or virus‐infected cells.
Eukaryotic Chromosomes
Authors: Bickmore Wendy A
Published: September 2006

Chromosomes are the nucleoprotein structures that carry the genetic information. In eukaryotes they are located in the cell nucleus.
Nucleosomes: Structure and Function
Authors: Luger Karolin
Published: September 2006

The structure of the nucleosome core particle, the basic repeating unit in eukaryotic chromatin, allows us to view the role of histones in regulating transcription, and in assembling specialized chromatin domains in a structural context. The organization of eukaryotic DNA into chromatin has fundamental implications for our understanding of all cellular processes that use DNA as a substrate.
Chromosomes: Nonhistone Proteins
Authors: Holland Katalin A
Published: September 2006

Chromatin is a dynamic structure alternating between condensed and decondensed states, depending on the stage of the cell cycle. Nonhistone proteins play essential roles in both states, including higher‐order chromosome organization, differential chromosome packaging and local chromatin architecture.
Artificial Chromosomes
Authors: Roosen Gert , Velten Florian W , Vos† Jean‐Michel H
Published: September 2006

Artificial chromosomes are DNA molecules assembled
in vitro
from defined constituents, which guarantee stable maintenance of large DNA fragments with the properties of natural chromosomes. Artificial chromosomes are useful for genome sequencing programmes, for functional characterization of entire genomic regions and for the transduction of large DNA segments into human and nonhuman mammalian cells.
Cot Analysis: Single‐copy versus Repetitive
DNA
Authors: Graham Geoffrey J
Published: September 2006

DNA reassociation, analysed by Cot methods, has provided insights into the organization, uneven replication, evolution and expression of genomes, and into disease processes such as viral infection and cancer.
Chromosomes: Noncoding DNA (including Satellite DNA)
Authors: Moran John V , Morrish Tammy Ann
Published: September 2006

Noncoding DNA comprises a substantial fraction of the genomes of higher eukaryotes. It consists largely of introns, simple repetitive DNA sequences, and sequences derived from mobile genetic elements (i.e. transposable elements).
Gene Duplication and Redundancy
Authors: Wagner Andreas
Published: September 2006

Gene duplications create one or more copies of a gene in a genome. They are important forces of genome evolution which change genome size and lead to the evolution of new gene functions.
Heterochromatin and Euchromatin
Authors: Eissenberg Joel C , Elgin Sarah
Published: September 2006

Eukaryotes are characterized by the extensive packaging of their genomes, initially in a nucleosomal array, and further into higher order domains. Differential packaging is used as a mechanism of gene regulation, with stable silencing of large domains achieved by packaging the DNA into a heterochromatic structure.