bluuebunny/crossref_metadata_2025 huggingface dataset:
DNA
Methylation
Authors: Hornby David P
Published: September 2006

DNA methylation occurs in most living organisms and is the enzyme‐mediated transfer of a methyl group from
S
‐adenosyl‐
l
‐methionine to specific cytosine or adenine bases within the genome of that organism. The biological consequences of DNA methylation are thought to be diverse, ranging from resistance to bacteriophage infection in microorganisms to the programming of gene expression in mammals.
Genetic Networks
Authors: Coffman James A , Davidson Eric H
Published: September 2006

Gene expression is regulated by sequence‐specific protein–DNA interactions that occur within the
cis
‐regulatory domains of genes. Regulatory genes that encode DNA‐binding proteins both control, and are controlled by, the expression of other such regulatory genes. A set of genes whose activity is thus linked by specific
cis
‐
trans
regulatory interactions constitutes a genetic network.
Immunoglobulin Gene Construction: Human
Authors: Lucas Alexander H
Published: September 2006

Human immunoglobulin genes exist as tandem arrays of gene segments that undergo somatic recombination and hypermutation during B‐lymphocyte development. Together, these processes enable the generation of a vast repertoire of immunoglobulin molecules capable of recognizing and eliminating infectious agents.
Immunohistochemical Detection of Tissue and Cellular Antigens
Authors: Kroese Frans GM
Published: September 2006

Antibodies are excellent tools for detecting specific molecules in cells and tissues. Techniques have been developed utilizing antibodies to visualize otherwise invisible, and indistinguishable, cells, subcellular structures and molecules. Collectively these techniques are termed immunohistochemistry.
Immunoprecipitation Techniques
Authors: Scheidtmann Karl‐Heinz
Published: September 2006

Immunoprecipitations are based on two types of interaction: between antigen and antibody, and between antibody and an immunoadsorbent. The antigen–antibody complex will be bound to an insoluble matrix that can be pelleted and removed from the bulk protein. Immunoprecipitation allows rapid and efficient purification of proteins in a native and biochemically active form.
Chromatin Diminution
Authors: Tobler Heinz , Müller Fritz
Published: September 2006

Chromatin diminution is defined as chromosomal fragmentation, followed by the elimination of part of the chromosome during mitosis. The process was first observed in early cleavage divisions of the
Parascaris equorum
embryo by Boveri in 1887, and later on was also found to occur in some other parasitic nematodes, copepods and ciliates.
Targeted Mutagenesis in the Immune System
Authors: Roes Jürgen
Published: September 2006

Mice with defined mutations in any known gene can be created by homologous recombination in embryonic stem cells. The genetic approach is instrumental in delineating the mechanisms that control leucocyte development and immune response.
Polytene Chromosomes
Authors: Zhimulev Igor F
Published: September 2006

Polytene chromosomes are specific interphase chromosomes consisting of thousands of individual chromatids. For this reason they are very large and display a characteristic band–interband morphology. Polytene chromosomes are excellent subjects for cytogenetic studies.
Lymphocyte Activation Signals: Transduction
Authors: Watanabe Takeshi
Published: September 2006

Transmembrane signal transduction initiated by the antigen receptors on T and B cells is essential for various immune cell functions including cell activation, proliferation, anergy and clonal deletion, which determine the direction of immune responses.
Polyploidy
Authors: D'Amato Francesco , Durante Mauro
Published: September 2006

Polyploidy, changes in the number of whole sets of chromosomes, is a common process during differentiation of animal and plant cells. It is also an important process in species evolution.
Lymphocytes
Authors: Klaus Gerry GB
Published: September 2006

Lymphocytes are cells found in the bloodstream and lymphoid organs that make specific, inducible immune responses against infectious agents.
Lymphocytes: Antigen‐Induced Gene Activation
Authors: Madrenas Joaquín
Published: September 2006

Lymphocytes are generally activated upon antigen recognition by their clone‐specific surface receptors. Lymphocyte activation includes multiple signalling cascades that converge in the cell nucleus to cause significant changes in the pattern of gene expression. These changes determine the cell phenotype and ultimately, the type of immune response.
Lymphocyte Development
Authors: Klaus Gerry GB
Published: September 2006

Both B and T lymphocytes are derived from uncommitted precursor cells in the bone marrow. B cells complete their development in the marrow, a process that is accompanied by the expression of clonally distributed antigen receptors. T lymphocytes undergo a similar process, but this occurs in the thymus.
Paramutation in Plants
Authors: Hollick Jay B
Published: September 2006

Paramutation describes a directed, meiotically heritable alteration of gene regulation influenced by allelic interactions.
Macrophages
Authors: Bogdan Christian
Published: September 2006

Macrophages are an important component of the innate and adaptive immune system. Their ability to recognize, phagocytose and kill microbial pathogens is complemented by the production of a broad spectrum of pro‐ and anti‐inflammatory cytokines.
Antigenic Variation in Microbial Evasion of Immune Responses
Authors: Kotwal Girish J
Published: September 2006

Antigenic variation is the means by which certain pathogenic microorganisms evade immune surveillance. Through a variety of mechanisms, the antigenicity of their surface proteins is varied, thereby preventing the host organism from mounting an effective immune response.
Immune System: Manipulation
In Vivo
Authors: Bahr George M
Published: September 2006

The immune system is manipulated by procedures aimed at potentiating immune responses to cope efficiently with antigenic and microbial challenges or to inhibit tumour development. However, suppression or re‐education of the immune system is an essential strategy to control undesired immune reactions directed either to self or to transplanted antigens.
Immunodeficient Animals
Authors: Berglöf Anna , Sandstedt Karin , Smith CI Edvard
Published: September 2006

The creation of targeted mutations in the mouse and other animals has considerable utility in many areas of research in mammalian biology, and animals with well‐defined immune defects provide an excellent model for study of the immune system. Gene targeted knockout mice are widely used in exploring the mechanisms underlying the development and function of the immune system.
Immunological Danger Signals
Authors: Monestier Marc
Published: September 2006

The conventional understanding of the immune system is that it can differentiate self from nonself. In contrast, the danger theory proposes that the immune system does not react to foreign substances but instead responds to situations that are potentially harmful.
Antimicrobial Proteins and Peptides
Authors: Ganz Tomas , Lehrer Robert I
Published: September 2006

Antimicrobial proteins and peptides are important effectors of the innate and adaptive arms of the immune system. They interfere with microbial integrity or metabolism by targeting structures or nutrients specific to microbes.
Neutrophils
Authors: Kuijpers Taco W , Roos Dirk
Published: September 2006

Neutrophils are the major type of leucocytes in peripheral blood and protect against bacterial and fungal infections. Neutrophils are equipped with a machinery to sense the site of an infection, to move towards the invading microorganisms, and to ingest and kill them.
Antibody Responses: Development
Authors: Wingren Christer
Published: September 2006

Antibodies are produced by B cells in response to foreign substances (antigens) such as bacteria and viruses. The development of the antibody response is dependent on the type of antigen and whether the immune system has previously encountered the antigen.
Antigen Presentation to Lymphocytes
Authors: Wang Jiyang O , Watanabe Takeshi
Published: September 2006

Antigen presentation to T and B lymphocytes by antigen‐presenting cells plays a central role in the initiation and regulation of adaptive immune responses.
Antigen Recognition by Lymphocytes
Authors: Gachlin Gabriel , Michelin Olivier , Luescher Immanuel F , Cambiaggi Anna
Published: September 2006

Mature B and T lymphocytes, as well as natural killer (NK) cells, express on their surfaces receptors that recognize antigen and elicit effector functions. B and T cell receptors are encoded by genes formed by rearrangement, but receptors utilized by NK cells are not.
Immunity: Humoral and Cellular
Authors: Honeyman MC , Harrison LC
Published: September 2006

Immune responses are controlled by both the innate immune system that is rapidly reactive to generic pathogen‐specific molecules, and the adaptive immune system that is slower but antigen‐specific and has memory.
Immunodeficiency
Authors: Roberts Robert L , Stiehm E Richard
Published: September 2006

Immunodeficiency is a condition caused by one or more immune system defects and is characterized clinically by increased susceptibility to infections with consequent severe, acute, recurrent or chronic disease. An immunodeficiency disorder should be considered in anyone with infections that are unusually frequent, severe and resistant; without a symptom‐free interval; from an unusual organism; or with unexpected or severe complications. Immunodeficiencies may be either primary or secondary.
Immunodeficiency, Primary: Affecting the Adaptive Immune System
Authors: Vihinen Mauno
Published: September 2006

Primary immunodeficiency (PID) is an intrinsic defect of the immune system. Patients with PID have increased susceptibility to recurrent and persistent infections, but other symptoms are also common.
Immunodeficiency: Secondary
Authors: Gupta Sudhir , Fernandes Gabriel
Published: September 2006

Immune deficiencies that develop in previously immunologically intact individuals are called secondary immunodeficiencies; they are a result of diverse external factors (infections, surgery and trauma, malnutrition, drugs) and a number of human diseases, including malignancy, nephrotic syndrome and protein‐losing enteropathy. Immunodeficiencies render the host markedly susceptible to viral and bacterial infections.
Immunosuppressive Drugs
Authors: Ringe Burckhardt , Braun Felix , Christians Uwe
Published: September 2006

Immunosuppressive drugs are used in the prevention or treatment of acute and chronic rejection of bone marrow and organ transplants. New immunosuppressants have created a large spectrum of drugs with different mechanisms of action, which allows the use of combinations of drugs to maintain effective immunosuppression with acceptable side effects.
T Lymphocyte Responses: Development
Authors: Gajewski Thomas F , Alegre Maria‐Luisa
Published: September 2006

Naive T cells require stimulation to differentiate and acquire most effector functions. This occurs in lymph nodes, depends on antigen recognition as well as on soluble and membrane‐bound factors, and can give rise to different types of immune responses.
Transplantation of Haematopoietic Stem Cells
Authors: Chen Christine , Keating Armand
Published: September 2006

Haematopoietic stem cell transplantation involves the infusion of blood progenitor cells (stem cells) into patients with damaged bone marrow in order to restore normal marrow function. Stem cells may be obtained from a healthy donor (allogeneic) or from the patients themselves (autologous).
Xenotransplantation
Authors: Lanza Robert P , Cooper David KC
Published: September 2006

The transplantation of organs and tissues across a species boundary is called xenotransplantation. Although the ability to transplant animal organs into humans would provide a solution to the problem of donor organ supply, the subject has generated widescale controversy, not only over the ethics surrounding the use of animals, but over the possibility that animal‐borne pathogens similar to the acquired immune deficiency syndrome (AIDS) virus could spread into the human population at large.
Cell Motility
Authors: Stebbings Howard
Published: September 2006

Movement is a major characteristic of living organisms, and can take the form either of movements of cells or of movements within cells themselves.
Cytoskeleton
Authors: Insall Robert , Machesky Laura
Published: September 2006

The cytoskeleton is a fibrous meshwork of three major components – actin microfilaments, microtubules and intermediate filaments. These are assembled from soluble precursors, under precise control by many different cellular processes. Other proteins interlink filaments or travel along with them. The cytoskeleton is found in all eukaryotic cells, and is required both for the maintenance of cell structure and for the organization of many aspects of cell movement.
Polymerization Dynamics of Cytoskeletal Filaments
Authors: Maciver Sutherland K
Published: September 2006

Polymerization dynamics is the description of the equilibrium between polymeric and monomeric states. The proteins of the cytoskeleton are able to polymerize and depolymerize through continuous cycles of addition or subtraction of monomer units, and the cytoskeleton is not a static entity.
Cilia and Flagella
Authors: Linck Richard W
Published: September 2006

Cilia and flagella are whip‐like, cellular appendages composed of microtubules. They function to propel cells through their environment, to transport extracellular substances required for the development and survival of the organism, and to provide for sensory reception.
Intermediate Filaments
Authors: Foisner Roland
Published: September 2006

Intermediate filaments form a major structural network in most eukaryotic cells; their only known function is to protect cells and tissues from disintegration by mechanical stress. They are formed by a heterogeneous class of proteins which share common structural elements and are expressed in a tissue and differentiation‐dependent manner.
Cell Membrane Features
Authors: Yeagle Philip L
Published: September 2006

The membranes of living cells support much of the functionality of biology. From the subcellular level of organelles to the supercellular level of cell–cell interactions, membranes provide the structures necessary for biological function and organization, as well as regulation of function.
Membrane Dynamics
Authors: Tamm Lukas K , Kiessling Volker , Wagner Michael L
Published: September 2006

Biological membranes are fluid dynamic closed structures that separate the inside from the outside of cells and compartments within cells. Proteins are inserted into random or more organized regions of a bimolecular ordered fluid film of lipids, where they display different degrees of motion within the plane of the membrane, but almost no (flip‐flop) motion across the lipid bilayer.
Ion Transport Across Nonexcitable Membranes
Authors: Reuss Luis
Published: September 2006

Ion transport in nonexcitable cell membranes occurs by active and passive mechanisms mediated by three kinds of integral membrane proteins (pumps, carriers and channels). The coordinated operation of these proteins establishes and maintains ion concentration gradients across the plasma membrane. These gradients are essential for cell function.
Calcium Signalling and Regulation of Cell Function
Authors: Bootman Martin D , Lipp Peter
Published: September 2006

The calcium ion (Ca
2+
) is an almost universal intracellular messenger, controlling a diverse range of cellular processes such as gene transcription, muscle contraction and cell proliferation.
Cell Membranes: Intracellular pH and Electrochemical Potential
Authors: Gilmore Adam M
Published: September 2006

Cell metabolism requires transmembrane proton and electrochemical gradients to synthesize adenosine 5′‐triphosphate (ATP), translocate ions, proteins and metabolites and regulate other vital activities.
Cell Macromolecules
Authors: Griggs Jeremy , Bray Dennis
Published: September 2006

Macromolecules: nucleic acids, proteins and polysaccharides,
form the molecular basis of all living organisms. Molecular recognition
between macromolecules governs all of the most sophisticated processes in
cells.
Autoimmune Disease: Pathogenesis
Authors: Bellone Matteo
Published: September 2006

Autoimmune diseases are a vast array of organ‐specific as well as systemic diseases, whose pathogenesis stems from the activation of B and/or T lymphocytes reacting against antigens of the body's own tissues (defined as ‘self’).
Immunology: Comparative Immunology of Mammals
Authors: Entrican Gary
Published: September 2006

The mammalian immune system is a complex, coordinated and finely controlled series of interactions between cells and molecules which has evolved to protect the host against disease. Mammals consist of a diverse group of animals in which the immune system has been subjected to a variety of selective pressures. This is reflected in differences in the organization and function of their immune systems.
Major Histocompatibility Complex: Disease Associations
Authors: Alper Chester A
Published: September 2006

Human major histocompatibility complex (MHC) alleles can be used as markers for a wide variety of autoimmune and other disorders. The interpretation of and possible bases for these associations can be considered in relation to conserved extended MHC haplotypes.
Crassulacean Acid Metabolism
Authors: Lüttge Ulrich
Published: September 2006

Crassulacean acid metabolism (CAM) is a CO
2
acquisition, CO
2
transient storage and CO
2
concentrating mechanism based on organic acid synthesis. In this variant of photosynthesis CO
2
can be fixed nocturnally in the dark and is used during the day for assimilation in the light.
Xylem Structure and Function
Authors: Myburg Alexander A , Sederoff Ronald R
Published: September 2006

Vascular plants have evolved a highly specialized tissue, called xylem, which provides mechanical support and transports water, mineral nutrients and phytohormonal signals in the plant. Although it is the most abundant biological tissue on earth, much remains to be learned about the structure, function, development and evolution of xylem and of the genes that regulate the processes.
Anoxia in Plants
Authors: Sachs Martin M
Published: September 2006

Flooding is a stress that crop plants frequently encounter and results in huge economic losses. Studies on the effects of flooding at the molecular level may lead to improvements that will result in flood‐tolerant crop plants.
Heavy Metal Adaptation
Authors: Herrera‐Estrella Luis Rafael , Guevara‐García Angel Arturo , López‐Bucio José
Published: September 2006

The adaptive responses of living organisms to heavy metals include physiological, anatomical and ecological mechanisms, some of which are highly conserved in nature. These adaptive mechanisms enable certain species to survive even in the presence of high concentrations of these toxic elements.
Plant Temperature Stress
Authors: Hayashi Hidenori
Published: September 2006

Plant temperature stress is defined as any drop or rise in temperature that causes reversible or irreversible inactivation of physiological processes or lethal injury in plants.
Plant Responses to Wounding
Authors: Sánchez‐Serrano Jose J
Published: September 2006

Plants react to mechanical damage by activating a set of wound‐responsive genes, whose function is devoted to plant healing and prevention of subsequent pest and pathogen attacks. A wound‐signalling cascade initiated at the site of injury is responsible for gene activation in local and systemic tissues.
Plant Defences Against Herbivore and Insect Attack
Authors: Schardl Christopher L
Published: September 2006

Plants deploy a number of defences against herbivore and insect attack. A primary defence is the production of toxins to poison the attackers. Other strategies include the development of thorns and tough unpalatable tissue to deter herbivores, and the recruitment of parasitoids and predators that attack herbivores.
Plant Storage Products (Carbohydrates, Oils and Proteins)
Authors: Bewley J Derek
Published: September 2006

The majority of foods consumed by humans and their domesticated animals used as food sources are ultimately obtained from plants, especially seeds. The storage products in seeds are predominately carbohydrates, oils and proteins, which are synthesized and stored in specialized tissues during seed development, and are utilized following germination to support early growth of the seedling.
Peptide Bonds, Disulfide Bonds and Properties of Small Peptides
Authors: Gilbert Hiram F
Published: September 2006

The peptide bond is an amide that links amino acids into head‐to‐tail polymers during the synthesis of proteins. Disulfide crosslinks stabilize specific conformations of peptides and proteins. Small peptides can be useful model systems for investigating protein structure and function.
Nucleotides: Structure and Properties
Authors: Bowater Richard Peter
Published: September 2006

Nucleotides consist of a nitrogen‐containing base, a five‐carbon sugar, and one or more phosphate groups. Cells contain many types of nucleotides which play a central role in a wide variety of cellular processes, including metabolic regulation and the storage and utilization of genetic information.
DNA: Natural Single‐stranded
Authors: Ranu Rajinder S
Published: September 2006

Single‐stranded circular or linear viral genomes have been used as model systems to investigate the mechanisms of DNA replication and gene expression and for the development of highly versatile cloning vectors. Flexible single‐stranded DNA can form hairpin/secondary structures by base pairing between regions of intramolecular sequence complementarity. Such structures are readily detected and appear to play important roles in virus‐associated functions
in vivo
.
Protein–Ligand Interactions: General Description
Authors: Dunn Michael F
Published: September 2006

Protein–ligand interactions are fundamental to almost all processes that take place in living organisms. They enable one molecule to recognize another and the transmission of signals via molecular complementarity is essential to all life.
Nuclear Envelope: Organization and Dynamics
Authors: Burke Brian
Published: September 2006

The nuclear envelope regulates the passage of molecules between the nucleus and cytoplasm and plays an important role in the maintenance of nuclear structure. During cell division in higher organisms, the nuclear envelope undergoes a complex cycle of disassembly followed by reassembly in order to permit segregation of the chromosomes by the mitotic spindle.
Nuclear–Cytoplasmic Transport
Authors: Silver Pamela A , Ferrigno Paul
Published: September 2006

In eukaryotic cells, RNA synthesis in the nucleus is separated from protein synthesis in the cytoplasm by the nuclear envelope. Against a background of emerging information concerning the molecular mechanisms of nucleo‐cytoplasmic transport, understanding the contribution of this exchange to cellular organization is one of the major challenges in cell biology.
Nucleolus
Authors: Shaw Peter J
Published: September 2006

The nucleolus is a nuclear substructure where the genes for three of the four ribosomal RNAs are transcribed and where ribosomal subunits are assembled.
Cell Cycle
Authors: Stein Gary S , van Wijnen André J , Stein Janet L , Lian Jane B , Owen Thomas A
Published: September 2006

Each period of the cell cycle requires selective expression of genes that encode cell cycle regulatory proteins. A broad spectrum of signalling mechanisms integrate and amplify growth‐related regulatory cues that mediate fidelity of cell cycle control.
Meiosis
Authors: Kohli Jürg , Hartsuiker Edgar
Published: September 2006

Meiosis is the process leading to formation of the haploid gametes from diploid cells.
Cell Cycle: Regulation by Cyclins
Authors: Kitazono Ana A , Gerald Jonathan N Fitz , Kron Stephen J
Published: September 2006

The cell cycle is defined as the periodic occurrence of events that are coordinately driven by the cyclin‐dependent kinases (CDKs). Cyclins are structurally related proteins whose levels fluctuate throughout the cell cycle. These CDK activators also impart distinct substrate specificity to CDKs for the temporal regulation of cell division.
Citric Acid Cycle
Authors: LaNoue Kathryn F
Published: September 2006

The citric acid cycle is a metabolic pathway common to aerobic cells by which carbohydrates, fats and amino acids are oxidized to carbon dioxide and water. Enzymes catalyse the condensation of two‐ and four‐carbon compounds to citric acid, and then enzymatic oxidations and decarboxylations regenerate the four‐carbon starting compound plus CO
2
and H
2
O. The energy available from the downhill flow of electrons to oxygen is used indirectly for the synthesis of ATP, the energy currency of the cell.
Electron Carriers: Proteins and Cofactors in Oxidative Phosphorylation
Authors: Roehm Klaus‐Heinrich
Published: September 2006

Biological electron transfer is mediated by a heterogeneous group of redox cofactors. Most of these compounds are firmly bound by proteins, others migrate freely within membranes, and some are soluble. The orderly flow of electrons through chains of such cofactors is fundamental to the generation of metabolic energy.
Oxidative Stress
Authors: Fridovich Irwin
Published: September 2006

Aerobes derive multiple benefits from molecular oxygen (O
2
). At the same time, O
2
imposes serious health threats to survival and these necessitate elaborate defences.
Mitochondria: Origin
Authors: Thorsness Peter E , Hanekamp Theodor
Published: September 2006

Mitochondria are double‐membrane cellular organelles containing their own genetic system and are found in nearly every eukaryotic cell. The endosymbiotic hypothesis postulates that a proto‐mitochondrion, an ancestor of present‐day bacteria, colonized a eukaryotic cell and established a symbiotic relationship to the mutual benefit of both organisms.
Nitrogenase Complex
Authors: Ludden Paul W
Published: September 2006

The nitrogenase complex carries out the fixation of nitrogen by reducing molecular dinitrogen (N2) to ammonium () and also reduces acetylene to ethylene. The two component proteins are dinitrogenase and dinitrogenase reductase. Although different metals can form the metal clusters contained in nitrogenase proteins, all nitrogenases have similar properties. The nitrogenase enzyme system is widely distributed among the Bacteria and the Archaea, with protein sequences highly conserved across the kingdoms.
Urea Cycle
Authors: Tuchman Mendel
Published: September 2006

The mammalian urea cycle, discovered by Krebs and Henseleit in 1932, takes place in the liver. It is the main chemical pathway for disposing of ammonium nitrogen.
Membrane Lipid Biosynthesis
Authors: Vance Jean E
Published: September 2006

Biological membranes consist of an enormously complicated array of many species of lipids, delineating interior from exterior and internal cellular compartments, and also generating second messenger compounds. A wide variety of enzymes are involved in the biosynthesis of these membrane lipids. Some human diseases arise from defects in enzymes that break down the lipids and rarely from defects in their biosynthesis.
Cholesterol, Steroid and Isoprenoid Biosynthesis
Authors: Auchus Richard J , Adams Christopher M
Published: September 2006

Steroids, sterols, and many other natural products all derive from isoprenoid building blocks via two common biosynthetic pathways. The subsequent processing of the structural core yields specific products that possess diverse structures and biological activities.
Nucleotide Synthesis
De Novo
Authors: Traut Thomas
Published: September 2006

Nucleotides are ubiquitous molecules that function in many biochemical processes as building blocks, or as a source of energy, or as cofactors. This central role requires their continued biosynthesis from readily available precursors, and this process is defined as
de novo
nucleotide synthesis.
Thymidylate Synthesis
Authors: Blakley Raymond L
Published: September 2006

Thymidylate is synthesized from deoxyuridylate and methylenetetrahydrofolate by thymidylate synthase, but dihydrofolate reductase and serine hydroxymethyltransferase are required to regenerate methylene tetrahydrofolate. Inhibitors of the synthase and the reductase arrest cell replication and are used in the treatment of cancer.
Nucleotide Synthesis via Salvage Pathway
Authors: Nyhan William L
Published: September 2006

The biosynthesis of purine and pyrimidine nucleotides takes place overde novosynthetic pathways from small molecules and by salvage pathways from preformed purine or pyrimidine bases or nucleosides. The pathways ofde novosynthesis are the same in animals and microorganisms.
Insulin Action: Molecular Basis of Diabetes
Authors: Najjar Sonia
Published: September 2006

Unbalanced regulation of the signalling cascades that mediate insulin action in the cell leads to diabetes mellitus. Thus, identification of the basic mechanism of insulin action promotes our understanding of the molecular basis of diabetes and the development of better therapeutic interventions.
Inherited Diseases of Intermediary Metabolism: Molecular Basis
Authors: Grabowski Gregory A
Published: September 2006

Inherited abnormalities in the complex pathways of carbohydrate, amino and organic acids and lipids lead to the inborn errors of metabolism. A variety of genetic aberrations lead to single or multiple protein/enzyme defects at the translational, post‐translational and organelle targeting levels that lead to the disease biochemistry and clinical manifestations.
Histamine Biosynthesis and Function
Authors: Homaidan Fadia R , Chakroun Iman , El‐Sabban Marwan E
Published: September 2006

Histamine, a chemical messenger, was originally identified mainly in mast cells, but was later found in basophils, platelets, enterochromaffin‐like cells, endothelial cells, and neurons. It is implicated in numerous physiological and pathophysiological processes including allergic reactions, vasodilatation and vasoconstriction, gastric acid secretion and neurotransmission.
Toxin Action: Molecular Mechanisms
Authors: Cassel Dan , Menez Andre , Gordon Dalia
Published: September 2006

Toxins are compounds of different nature, including cytotoxic proteins, polypeptides of variable lengths, alkaloids and others. They are produced by different organisms and are poisonous to animals. Toxins act by affecting functions that are essential to the survival of the cell or to its communication with its environment. Because the action of many toxins is highly specific for a particular cellular target, toxins have been valuable in elucidating the mechanisms that maintain and control essential cellular functions.
Regulatory Cascades: Function and Properties
Authors: Ferrell James E
Published: September 2006

A regulatory cascade is a system of signal‐transducing proteins that relays signals from receptors to the proteins that carry out a cell's response. Cascades can amplify, integrate, filter and sharpen the signals they transmit.
Thrombin
Authors: Narayanan AS , Thiagarajan P
Published: September 2006

Thrombin is a serine protease that has narrower substrate specificity and cleaves fewer peptide bonds than pancreatic serine proteases, with which it shares a common evolutionary ancestor. With its procoagulant and anticoagulant functions it plays a central role in thrombosis and haemostasis and it is an agonist for a number of cellular responses during inflammation and wound repair.
Ames/
Salmonella
Assay: A Bacterial Test for Mutagens
Authors: Felton James S , Wu Rebekah W
Published: September 2006

The Ames/
Salmonella
mutation assay is the most widely used test to determine whether chemicals can cause genetic changes (mutations) potentially leading to cancer. Chemicals related to industry, farming, foods, drugs and the environment have been discovered to be mutagens with this simple assay.
Anaerobic Respiration
Authors: Payne William J
Published: September 2006

Anaerobic respiration is growth‐supporting utilization by some archaea, bacteria and filamentous fungi of nitrogen oxides, carbon dioxide, sulfate or various metals and organic materials as terminal oxidants in place of oxygen. In nature, the processes exert significant ecological and economic impacts that may be either beneficial or deleterious.
Bacterial Fermentation
Authors: Müller Volker
Published: September 2006

Under anaerobic conditions, in the dark and in the absence of electron acceptors, organic compounds are catabolized by strictly anaerobic or facultatively anaerobic bacteria by internally balanced oxidation–reduction reactions, a process called fermentation. In fermentation, the organic compound serves as both electron donor and acceptor, and adenosine triphosphate is synthesized by substrate level phosphorylation.
Bacterial Genetic Exchange
Authors: McGee David J , Coker Christopher , Harro Janette M , Mobley Harry LT
Published: September 2006

Exchange of genetic material between bacterial species is mediated by the basic processes of conjugation, transduction and transformation. This exchange is fundamental for bacterial evolution and adaptation in a dynamic environment.
Bacterial Cell Differentiation
Authors: Smith Christopher , Brun Yves
Published: September 2006

Bacteria utilize a variety of molecular mechanisms to achieve cell differentiation. The resulting developmental transformations generate specialized cell types that increase their ability to survive in their environment.
Photoautotrophy
Authors: Eraso Jesus M , Kaplan Samuel
Published: September 2006

Photoautotrophy is the process by which organisms convert radiant energy into biologically useful energy and synthesize metabolic compounds using only carbon dioxide or carbonates as a source of carbon.
Quorum Sensing
Authors: Holden Matthew TG , Williams Paul
Published: September 2006

Many bacterial processes are dependent on the presence of a population of cells. Quorum sensing is a term that has been coined to describe the ability of bacteria to sense the population of bacteria around them. Bacteria achieve this by detecting the concentration of signalling molecules that they secrete into the surrounding environment.
Tumours: Targeting of Monoclonal Antibodies for Imaging and Potential for Therapy
Authors: Mach Jean‐Pierre
Published: September 2006

Monoclonal antibodies directed against tumour‐associated antigens labelled with radioisotopes localize specifically into tumour after intravenous injection. This property is used for diagnostic tumour imaging by immunoscintigraphy and in some clinical situations for radioimmunotherapy.
Autoimmune Disease: Treatment
Authors: Burkhardt Harald , Kalden Joachim R
Published: September 2006

In recent years substantial progress has been made in understanding the mechanisms of inflammation and autoimmunity. In an attempt to interfere selectively with pathogenic pathways, a variety of synthetic as well as biological agents have been designed that target molecules of crucial importance for (auto)immune responses.
Immunity: Experimental Transfer
Authors: Claësson Mogens H , Hald Jesper
Published: September 2006

Transfers of biological reagents, cellular or humoral, have been a central theme in experimental immunology, including many areas of tumour immunology. Such transfers include lymphokine‐activated killer (LAK) cells, tumour‐infiltrating lymphocytes (TILs) and antigen‐specific cytotoxic T‐cell (CTL) lines and clones, monoclonal antibodies (mAbs) and cytokines.
Phagocytosis: Techniques
Authors: Dileepan Kottarappat N
Published: September 2006

Phagocytosis is a complex cellular process in which particulate material, such as invading microorganisms and dead cells, is engulfed and eliminated by phagocytes.
Chromosome Preparation and Banding
Authors: Moore Charleen M , Best Robert G
Published: September 2006

Reliable techniques have been developed to produce large numbers of mitotic cells and to collect them at metaphase in order to visualize individual chromosomes. After cell culture and spreading of the metaphases onto slides, the chromosomes are stained to produce unique banding patterns or to reveal specialized structures. Molecular techniques have been developed to identify submicroscopic rearrangements and to compare karyotypes of different species.
Chromosomal Syndromes and Genetic Disease
Authors: Luthardt Frederick W , Keitges Elisabeth
Published: September 2006

The normal human chromosome complement consists of 46 chromosomes comprising 22 morphologically different pairs of autosomes and one pair of sex chromosomes. Variation in either chromosome number or structure frequently results in significant mental and/or clinical abnormalities. Chromosomal syndromes are associated with specific chromosomal abnormalities.
Human Chromosome Evolution
Authors: Holmquist Gerald P , Wienberg Johannes
Published: September 2006

During mammalian genome evolution, nuclear DNA content remained more or less unchanged and the chromosomal banding pattern was maintained with the exception of occasional chromosomal rearrangements. Chromosomal rearrangements occur frequently in individuals but only occasionally are they fixed into the common karyotype of a new species. The fixed rearrangements are passed on during evolution and unambiguously reveal how mammalian species are related to each other.
X‐Chromosome Inactivation
Authors: Gartler Stanley M , Goldman Michael A
Published: September 2006

In female mammals, one of the X‐chromosomes is transcriptionally silenced by heterochromatin formation to bring about equal expression of X‐linked genes in XX females and XY males.
Deafness
Authors: Petit Christine , Weil Dominique
Published: September 2006

Hearing loss is the most frequent of the sensory defects. 30% of the cases are syndromic (deafness is accompanied by other symptoms). The nonsyndromic forms can be due to environmental or genetic factors. A variety of genes can be responsible for deafness, among them several connexins, unconventional myosins, and mitochondrial genes.
Lesch–Nyhan Syndrome
Authors: Gregorio Laura De , Nyhan William L
Published: September 2006

Lesch–Nyhan syndrome is a severe X‐linked condition caused by deficiency of the purine‐salvage enzyme hypoxanthine–guanine phosphoribosyltransferase (HPRT), leading to hyperuricaemia and different manifestations of neurological abnormality.
Y‐chromosome‐linked Traits
Authors: Graves Jennifer A Marshall
Published: September 2006

Male mammals have a single X and a Y chromosome. The Y chromosome is small, containing a lot of repeated sequences and few active genes, but carries a sex‐determining factor, which determines maleness, as well as other male‐specific functions such as steps in spermatogenesis. Molecular work suggests that the Y is best understood in terms of its evolutionary history.
Plant Bioenergetics
Authors: Grace Stephen C
Published: September 2006

Cellular energy metabolism drives the biochemical processes essential for the growth and survival of all organisms. Nearly all forms of life depend on the photosynthetic activity of plants to provide electron‐rich substrates to fuel metabolism. Despite an overall low efficiency of conversion, the trapping of solar energy by photosynthesis is the only source of free energy used to sustain life.
Cancer
Authors: Alison Malcolm R
Published: September 2006

Cancer is a potentially fatal disease caused mainly by
environmental factors that mutate genes encoding critical cell‐regulatory
proteins. The resultant aberrant cell behaviour leads to expansive masses of
abnormal cells that destroy surrounding normal tissue and can spread to vital
organs resulting in disseminated disease, commonly a harbinger of imminent
patient death.
Oncogenes
Authors: Perry Amanda R
Published: September 2006

Oncogenes are the activated forms of normal cellular genes whose protein products are involved in key signalling pathways governing cell survival, proliferation and differentiation. Through a variety of mechanisms, including viral infection and chemical‐induced mutation, these proteins become hyperactive or overexpressed and contribute to the cell growth and behaviour typical of cancer cells.
Tumour Suppressor Genes
Authors: Skolnik Jeffrey M , Fisher David E
Published: September 2006

Tumour suppressor genes are a group of genes whose loss contributes to malignancy. A summary of the mechanisms by which tumour suppressor genes may act, the mutations which lead to tumorigenesis, and the clinical implications of these phenomena are presented.
Environmental Carcinogens and Mutagens
Authors: Loechler Edward L
Published: September 2006

Environmental agents (chemicals, radiation and viruses) can be carcinogens (cancer‐causing substances) and mutagens (substances that alter DNA). The steps from mutagen/carcinogen to tumour involve mutagen/carcinogen activation by metabolism, reaction with DNA to give a DNA adduct and DNA replication of the adduct, resulting in a mutation; a mutation in a cancer gene may result in enhanced growth potential, and ultimately in tumour growth.
Ageing
Authors: Turker Mitchell
Published: September 2006

Ageing is a progressive decline in organismal viability that ultimately results in death.
Sleep Disorders
Authors: Sinton Christopher M , McCarley Robert W
Published: September 2006

An understanding of possible mechanisms involved in sleep induction and maintenance may lead to the comprehension, treatment and eventual prevention of some sleep disorders.
Mood Disorders
Authors: Reus Victor I
Published: September 2006

Moods are fundamental emotional states that govern internal experience and adaptive survival. Clinical disorders of mood are prevalent and emerge out of a confluence of genetic, developmental and environmental risk factors to adversely affect morbidity, mortality and function. Although the understanding of causation remains obscure, current treatment options are numerous and highly effective in the majority of cases.
RNA Virus Genomes
Authors: Domingo Esteban
Published: September 2006

Viruses contain either DNA or RNA as their genetic material. The RNA viruses are the most abundant group of molecular parasites of cells and differentiated organisms. About 75% of viruses that are pathogenic for humans, animals or plants contain RNA as genetic material. Genomic RNA shows remarkable variations in structure, size and replication mechanism.
Plasmids
Authors: Novick Richard P
Published: September 2006

Plasmids are nonessential extrachromosomal genetic elements that replicate autonomously and control their own replication. Most bacterial plasmids are circular supercoiled DNA molecules that range in size from one to several hundred kilobase pairs and exist in a characteristic number of copies per cell, ranging from one to several hundred.
Agrobacterium tumefaciens
‐mediated Transformation of Plant Cells
Authors: Binns Andrew , Campbell Angela
Published: September 2006

Agrobacterium tumefaciens
is a Gram‐negative soil bacterium that causes plant tumours by transferring a portion of DNA from a resident ‘tumour inducing’ (Ti) plasmid into plant cells where it is integrated into a plant chromosome and expressed. This bacteria's capacity for DNA transfer is the basis of most current plant genetic engineering and make it a model system for the study of pathogenic bacteria that transfer virulence factors to any eukaryotic cell.
Drosophila
Oogenesis
Authors: de Cuevas Margaret
Published: September 2006

Oogenesis is the process by which germ cells develop into eggs. In
Drosophila
, this process takes about a week and is accompanied by complex interactions between many different cell types in and around the ovary.
Drosophila
Embryo: Maternal Interactions in Specification of the Anterior–Posterior Axis
Authors: Lasko Paul
Published: September 2006

In Drosophila, the anterior–posterior axis of the body plan is established during egg development by maternally expressed molecules.
Caenorhabditis elegans
Embryogenesis: Genetic Analysis of Cell Specification
Authors: Edgar Lois G
Published: September 2006

Cell fate in some early embryonic blastomeres of
C. elegans
is specified cell autonomously (mosaic development), by proteins localized by cytoskeletal machinery controlled by the
par
gene products, and in others by cell‐to‐cell signalling (regulative development), using either the APX‐1–GLP‐1 (Notch‐like) or the Wnt signalling pathway.
Drosophila
Embryo: Homeotic Genes in Specification of the Anterior–Posterior Axis
Authors: Rogers Bryan T
Published: September 2006

The products of the homeotic genes of
Drosophila melanogaster
are a set of transcription factors, each with its own unique expression
pattern and battery of target genes. It is the combination of these two
features by which, as a group, the homeotic genes are capable of specifying
the collections of cell types characteristic of different regions of the
animal body.
Drosophila
Embryo: Dorsal‐ventral Specification
Authors: Lin Pei‐Hui , Steward Ruth
Published: September 2006

The dorsal‐ventral pattern of the
Drosophila
embryo is established by sequential signalling pathways that transmit spatial information from the egg chamber to the zygote.
Drosophila
Patterning: Delta–Notch Interactions
Authors: Desbordes Sabrina , López‐Schier Hernán
Published: September 2006

Canonical and noncanonical activities of the Notch receptor
combine to organize the morphology of tissues and organs in
Drosophila melanogaster
.
Classification
Authors: Minelli Alessandro
Published: September 2006

A biological classification is a hierarchical arrangement of species and higher taxa, with the corresponding nomenclature; classification is also the part of systematic biology concerned with generating such an arrangement.
Universal Tree of Life
Authors: Brown James R
Published: September 2006

The universal tree of life represents the proposed evolutionary relationships among all cellular life forms (thereby excluding viruses). Gene sequence data has moved the focus of the universal tree away from emphasizing metazoan diversity to encompassing the greater genetic diversity found in prokaryotes and single‐cell eukaryotes. Presently, the conical universal tree includes three main urkingdoms or domains called the Archaea (archaebacteria), Bacteria (eubacteria) and Eukarya (eukaryotes) with the rooting in the Bacteria such that Archaea and Eukarya are sister groups. However, the evolutionary relationships among these three groups, and even the status of the Archaea, are still hotly debated among evolutionary biologists.
Agnatha (Lampreys, Hagfishes, Ostracoderms)
Authors: Janvier Philippe
Published: September 2006

Agnathans are an ensemble of jawless (non‐gnathostome) vertebrates, some of which are more closely related to the gnathostomes than others. Living agnathans fall into two groups, hagfishes (Hyperotreta) and lampreys (Hyperoartia), united into a higher group, the cyclostomes (Cyclostomi).
Amphibia
Authors: Oldham Robert S
Published: September 2006

The Amphibia includes the well‐known frogs, toads, salamanders and newts. They are ectothermic, quadrupedal vertebrates with a glandular skin, and a life cycle, in modern species, characterized by the metamorphosis of an aquatic larva into a terrestrial adult. They evolved from lobe‐finned fish in the Devonian and early amphibians are the ancestors of the amniotes.
Anura (Frogs)
Authors: Dundee Harold A
Published: September 2006

The order Anura is a widespread group of over 4000 species of frogs and toads, forming part of the class Amphibia. Adult anurans have a short vertebral column, no tail, stout forelimbs and long, webbed hindlimbs used for swimming and leaping. Most species have an aquatic larval stage, the tadpole.
Gymnophiona (Caecilians)
Authors: Milner Andrew R
Published: September 2006

The order Gymnophiona (also sometimes called Apoda or Caecilia) is a group of highly specialized tropical fossorial (burrowing) amphibians. Because most are burrowers, they are rarely seen and, until the last two decades, little was known of their biology. They have no widely used common names and are generally called caecilians. They are found in tropical South America, Africa, the Seychelles, the Indian subcontinent and parts of southeast Asia, but are absent from Madagascar and Australasia.