bluuebunny/crossref_metadata_2025 huggingface dataset:
Transfer
RNA
Modification
Authors: Motorin Yuri , Grosjean Henri
Published: September 2006

Naturally occurring transfer ribonucleic acid (tRNA) always contains numerous chemically altered nucleosides formed by enzymatic modification of the primary RNA transcript during the complex tRNA maturation process. These modifications favour correct folding and stabilize the tRNA architecture, protect RNAs against nucleolytic degradation and improve its performance in the different interactions in which tRNA is involved, namely in aminoacylation by cognate aminoacyl‐tRNA synthetases, interactions with initiation and elongation factors as well as in decoding of messenger RNA on the ribosome. In eukaryotic cells, RNA modification may also help in tRNA transport across internal membranes.
Protein Folding
In Vivo
Authors: Teter Sarah , Hartl F Ulrich
Published: September 2006

Proteins are composed of linear chains of amino acids. Upon synthesis in the cell, proteins must acquire a specific three‐dimensional structure, a process known as folding, before they can perform their various functions in the cell.
SOS
Response
Authors: Defais Martine , Devoret Raymond
Published: September 2006

Bacteria have developed an SOS response to mend DNA damage caused by deleterious agents such as radiations and chemicals. Mutagenesis, one of the SOS functions, has permitted bacteria to adapt to short‐ and long‐term adverse living conditions.
Thermodynamics in Biochemistry
Authors: Alberty Robert A
Published: September 2006

The thermodynamics of chemical reactions and biochemical reactions (enzyme‐catalysed reactions at specified pH) deals with equilibrium constants
K
of chemical reactions and apparent equilibrium constants
K
’ for biochemical reactions, reduction potentials for chemical half‐reactions, and apparent reduction potentials for biochemical half‐reactions.
Chlorophylls
Authors: Fujita Yuichi
Published: September 2006

Chlorophylls are a group of cyclic tetrapyrrole pigments that are involved in the light reactions of photosynthesis. All chlorophylls are synthesized from 5‐aminolaevulinic acid via multiple enzymatic reactions.
Selenocysteine
Authors: Böck August
Published: September 2006

The trace element selenium is present in the form of selenocysteine in selected proteins of organisms from all three lines of descent. Selenocysteine incorporation is DNA‐encoded, determined by the UGA codon, and occurs via a unique mechanism representing an expansion of the genetic code.
Fatty Acids: Structures and Properties
Authors: Rustan Arild C , Drevon Christian A
Published: September 2006

Fatty acids play a key role in metabolism: as a metabolic fuel, as a necessary component of all membranes, and as a gene regulator. In addition, fatty acids have a number of industrial uses.
Ribonucleases
Authors: Pingoud Alfred , Meiss Gregor
Published: September 2006

Ribonucleases are a very heterogeneous group of enzymes, both with respect to structure and function. They all catalyse the cleavage of phosphodiester bonds, endonucleolytically or exonucleolytically, with more or less specificity. They occur ubiquitously and are involved, directly or indirectly, in almost every cellular process.
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. Supercoiling increases the free energy of DNA and influences DNA metabolism by promoting or hindering specific enzymatic processes.
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.
Calcium‐binding Proteins
Authors: Schwaller Beat
Published: September 2006

Calcium ions act as important second messengers for many intracellular processes and the information contained in this calcium signal is modulated by specific calcium‐binding proteins. According to well‐conserved structural elements, these proteins can be grouped into different families including annexins, C2 domain proteins and EF‐hand proteins.
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. Salvage pathways are considerably more energy‐efficient thande novopathways, which require 5 (pyrimidine) or 6 (purine) moles of ATP for each mole of nucleotide produced.
Free Radicals and Other Reactive Species in Disease
Authors: Halliwell Barry
Published: September 2006

Free radicals can be generated in a wide variety of chemical and biological systems, including the formation of plastics, the ageing of paints, the combustion of fuels and in the human body. In living organisms, the levels of free radicals and other ‘reactive species’ are controlled by a complex web of antioxidant defences, which minimize (but do not completely prevent) oxidative damage to biomolecules.
Intracellular
p
H
Measurement
Authors: Szaszi Katalin , Grinstein Sergio
Published: September 2006

Measurement of intracellular pH requires preservation of cellular integrity. For this purpose, biophysical methods such as nuclear magnetic resonance, fluorescence spectroscopy and pH‐sensitive microelectrodes can be applied.
Protein Determination
Authors: Guttenberger Martin
Published: September 2006

Protein determination aims at estimating the concentration of protein by comparing the unknown sample with a known standard. Sample preparation and choice of a suitable standard are the most important criteria for the accuracy of the results.
Protein Kinases: Physiological Roles in Cell Signalling
Authors: Woodgett James Robert , Takahashi Mark
Published: September 2006

Protein kinases play multiple roles in cells and act as the primary messenger enzymes that coordinate cellular responses to the environment. This article discusses the different roles this class of molecules play in regulating processes such as cell death and proliferation as well as the disease consequences of their dysregulation.
Folates
Authors: Kisliuk Roy L
Published: September 2006

Folic acid is a vitamin required for normal growth. It was discovered as a stable factor in extracts of yeast and of liver, which cured anaemia in pregnant women. The preponderant forms of folic acid in tissues are tetrahydrofolate polyglutamates with single carbon adducts corresponding to methanol, formaldehyde and formate. Folates are essential for the enzymatic oxidation, reduction and transfer of single carbon units involved in the metabolism of thymidylate, purine nucleotides, methionine, serine, histidine and choline.
Gene Delivery by Viruses
Authors: Ginsburg Daniel S , Thyagarajan Bhaskar , Phillips Julie E , Calos Michele P
Published: September 2006

Viral vector systems are very useful for delivering genes to cells. Commonly used systems include vectors derived from retroviruses, lentiviruses, adenoviruses, adeno‐associated viruses and herpesviruses.
mRNA Formation: 3′ End
Authors: Wahle Elmar
Published: September 2006

The 3′ end of eukaryotic messenger ribonucleic acid (mRNA) is not generated by termination of transcription but by processing of the primary transcript. Posttranscriptional 3′ end formation almost always consists of cleavage of an internal phosphodiester bond, followed by the addition of a poly(A) tail to the upstream cleavage fragment.
Chromosome Function: Sex Differences
Authors: Mueller Jacob L , Wolfner Mariana F
Published: September 2006

The distinct development of females and males is usually the consequence of differences in their sex chromosome constitution. To compensate for these differences, the sexes adjust the expression of sex‐linked genes. Some inheritance patterns depend on the sex or sex chromosome make‐up of a parent.
Pyruvate Dehydrogenase Complex
Authors: Patel Mulchand S , Korotchkina Lioubov G
Published: September 2006

Pyruvate dehydrogenase complex (PDC) is a highly organized multienzyme complex that plays a key role in glucose metabolism providing a direct link between glycolysis and the tricarboxylic acid cycle. PDC is tightly regulated according to changing demands in glucose consumption in different tissues and under different nutritional and pathophysiological conditions.
Peptide Chain Elongation: Models of the Elongation Cycle
Authors: Nierhaus Knud H , Wilson Daniel N
Published: September 2006

Three models of the ribosomal elongation cycle are used to explain the mechanism of protein synthesis on the ribosome. These are the allosteric three‐site model, the hybrid site model and the α–ε model. Recent cryoelectron microscopy analyses significantly modify the current models.
Gene Expression: Decoding and Accuracy of Translation
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 , Wilson Daniel N
Published: September 2006

Formation of the peptide bond is the central enzymatic activity of ribosomes. The active centre resides on the large ribosomal subunit, and is made of nucleotides from domain V of the 23S‐type rRNA.
Calcium Signalling and Regulation of Cell Function
Authors: Bootman Martin D , Holmes Anthony M , Roderick H Llewelyn
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.
Primary Cell Cultures and Immortal Cell Lines
Authors: Stacey Glyn
Published: September 2006

Primary cell cultures can be established from tissue explants or, more usually, from disaggregated tissue samples. Cells that can be subcultured many times are called cell lines and examples have been isolated from diverse tissues and cell types. Continuous cell lines of unlimited lifespan can be generated by means of a number of immortalization techniques, although in most cases such cell lines have arisen spontaneously.
Peroxisomes: Methods for Preparation
Authors: Völkl Alfred , Fahimi H Dariush
Published: September 2006

Peroxisomes are ubiquitous cell organelles that are particularly enriched in mammalian liver and kidney. They contain oxidases producing hydrogen peroxide and catalase, which degrades it. Their main functions are in the metabolism of complex lipids such as bile acids, leucotrienes and prostaglandins. Peroxisomes can be isolated by classical density gradient centrifugation methods and by more recent immunochemical techniques.
Synaptic Vesicles: Methods for Preparation
Authors: Floor Erik
Published: September 2006

Synaptic vesicles are small organelles that store and release neurotransmitters at synapses. They can be purified from the brain or other sources to study their structure and function.
Calcium Channel Diversity
Authors: Dolphin Annette C
Published: September 2006

There are various subtypes of voltage‐dependent calcium channel that allow Ca
2+
levels in cells to be raised in response to depolarization.
Antibiotic Molecules: Intracellular
Authors: Borregaard Niels
Published: September 2006

Intracellular antibiotic molecules are the essential components of innate, i.e. nonadaptive, immunity. Some are stored proteins with highly specific antibiotic activity, others are stored peptides that have a broad antibacterial spectrum, yet others are short‐lived molecular reagents that are generated by specific activation of phagocytes, the cells equipped especially for microbicidal activity.
Bursa of Fabricius
Authors: Veistinen Elli , Lassila Olli
Published: September 2006

The bursa of Fabricius is known to play a central role in the development of the antibody‐producing B‐lymphocyte lineage in birds. The bursa provides an appropriate microenvironment for gene conversion events leading to antibody diversification.
Spleen
Authors: Steiniger Birte
Published: September 2006

The spleen is a secondary lymphoid organ present in all vertebrates. It is structurally complex and has a number of different functions such as immunological monitoring of bloodborne antigens, storage of blood and destruction of aged or abnormal blood cells. The importance of single functions and, in consequence, the microanatomy of the spleen vary among different species.
Blood Coagulation
Authors: Jesty Jolyon
Published: September 2006

The blood coagulation system acts in concert with the platelets to seal damaged blood vessels by the formation of a clot that consists of aggregated platelets interwoven with fibrin. Coagulation is initiated by the subendothelial membrane protein tissue factor and proceeds through a highly regulated proteolytic cascade to the production of thrombin and the fibrin clot.
Inflammation: Chronic
Authors: Kumar Rakesh K , Wakefield Denis
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.
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 ‐positive capsules contribute to the bacterial resistance of host immune responses.
Immunosuppressive Drugs
Authors: Ringe Burckhardt , Braun Felix
Published: September 2006

Immunosuppressive drugs are used for the prevention or treatment of rejection after transplantation of solid organs, tissues and cells, as well as therapy of autoimmune and a variety of other diseases. Primary goals of immunosuppression are: (1) to effectively control immune responses against foreign antigens, and (2) to minimize any undesired drug side effects and toxicities. The development of numerous substances, together with the understanding of their molecular action has paved the way to meet these goals, and to individualize immunosuppression. The objective of this inventory is to give a systematic overview on immunosuppressive agents currently in use or under evaluation for transplantation, as a guide for scientific research and clinical practice.
Acquired Immune Deficiency Syndrome (AIDS)
Authors: Siliciano Robert F
Published: September 2006

The acquired immune deficiency syndrome (AIDS) is a potentially fatal transmissible disease, caused by
Human immunodeficiency virus type 1
(HIV‐1). AIDS has claimed over 20 million lives and over 40 million people are infected with HIV‐1. While there is as yet no cure or effective vaccine for AIDS, there are treatments that can forestall the development of overt disease and restore immune function.
Hypersensitivity: Anaphylactic (Type I)
Authors: Bannon Gary A
Published: September 2006

Type I hypersensitivity reactions occur in individuals who have been previously sensitized to a specific allergen. They are the result of allergen recognition by immunoglobulin E on mast cells and basophils and cause a variety of symptoms such as itching or tingling of the lips, tongue or throat; nausea, vomiting and diarrhoea; sneezing, runny nose and wheezing, shortness of breath and coughing. In some cases, the reaction can be so severe that the circulatory system shuts down and tracheal swelling occurs, leading to a life‐threatening condition known as anaphylaxis.
Autoimmune Disease: Genetics
Authors: Santamaria Pere , Yang Yang
Published: September 2006

Autoimmune diseases result from an attack of the body's own tissues by the immune system. Genetic susceptibility and resistance to autoimmunity are primarily associated with highly polymorphic genes of the major histocompatibility complex and, to a lesser extent, with polygenic modifiers elsewhere in the genome.
Innate Immune Mechanisms: Nonself Recognition
Authors: Parish Christopher R
Published: September 2006

The innate immune system contains a range of cell‐bound and soluble proteins which eliminate pathogens by recognizing unique molecular patterns expressed by microorganisms, but not by host cells. Alternatively, host cells express proteins that protect them from attack by the alternative pathway of complement activation, whereas foreign organisms lack these protective proteins and are, therefore, susceptible to complement attack.
Histocompatibility Antigens
Authors: Mehra Narinder K
Published: September 2006

The histocompatibility antigens are cell surface glycoproteins expressed on nucleated cells whose major function is to bind peptides within the cell and present them at the cell surface for inspection by T cells of the immune system. These antigens are a part of the major histocompatibility complex, which exists in most vertebrate species and whose antigens were originally defined as the most important molecules involved in the rejection of transplanted tissues exchanged between individuals of the same species.
Atopy and Asthma
Authors: Yates Anne B , de Shazo Richard D
Published: September 2006

Atopy is the genetic propensity to develop an immunoglobulin E antibody response to common allergens. The most common clinical manifestations of atopy are allergic rhinitis, asthma and atopic dermatitis.
Monoclonal Antibodies: Therapeutic Uses
Authors: Zola Heddy
Published: September 2006

Monoclonal antibodies are biological products made in the laboratory. They use the ability of the immune system to make specific high‐affinity reagents to bind to almost any molecular structure. In recent years, the therapeutic applications of monoclonal antibodies have developed rapidly, and they currently form the fastest growing sector of the biotherapeutics industry.
Monoclonal Antibodies: Diagnostic Uses
Authors: Zola Heddy , Roberts Thomson Peter
Published: September 2006

Diagnosis of disease depends frequently on the identification, quantitation or localization of particular molecules, cells or organisms in tissue or body fluids. Antibodies, because of their exquisite specificity, are particularly useful reagents in this context, and monoclonal antibodies are often superior to polyclonal mixtures of antibodies. Monoclonal antibodies are used widely in the diagnostic laboratory.
Integrins: Signalling and Disease
Authors: Krissansen Geoffrey W , Danen Erik HJ
Published: September 2006

Cell‐surface adhesion molecules of the integrin family are not a passive glue, but rather are dynamic molecules that mediate the transfer of information across the membrane in both directions; influencing cell growth, the cell cycle, differentiation, programmed death, survival and motility. They contribute to the pathogenesis of a diverse array of acquired and hereditary diseases, and hence are major targets for therapeutic intervention.
Neonatal Infectious Disease
Authors: Menson EN , Lyall EGH
Published: September 2006

Manifestation of different infections in the newborn depends on the timing of infection (
in utero
, around delivery or after birth), the organism, the presence or absence of maternal immunity and the immune response of the infant.
Antibody Microarrays
Authors: Wingren Christer , Borrebaeck Carl
Published: September 2006

Antibody‐based microarray is a novel technology with great promise within proteomics. A microarray can be printed with thousands of antibodies carrying the desired specificities, the biological sample added (e.g. a proteome) and any specifically bound analytes detected. Global proteome analysis and protein expression profiling using this tool will provide new opportunities for biomarker discovery, drug target identification, disease diagnostics and insights into disease biology.
Toll‐like Receptors
Authors: Kaisho Tsuneyasu , Akira Shizuo
Published: September 2006

Toll‐like receptors are mainly expressed on antigen‐presenting cells and function as adjuvant receptors. Their pleiotropic functions depend on a variety of signalling components.
Lymphocytes: Antigen‐induced Gene Activation
Authors: Criado Gabriel , Madrenas Joaquín
Published: September 2006

Lymphocytes are activated upon antigen recognition by their clone‐specific surface antigen receptors. Lymphocyte activation includes multiple signalling cascades that converge in the cell nucleus to cause significant changes in the pattern of gene expression that determine the phenotype of activated lymphocytes and ultimately, the type of immune response.
Schwann Cells
Authors: Scherer Steven S , Arroyo Edgardo J
Published: September 2006

Schwann cells are the glial cells of the peripheral nervous system. They form myelin sheaths, which are essential for saltatory conduction in normal nerves, and promote axonal regeneration in damaged nerves. Myelinating Schwann cells are selectively vulnerable to certain inherited diseases.
Cocaine and Amphetamines
Authors: Rebec George V
Published: September 2006

As stimulants, cocaine and amphetamines heighten arousal and increase behavioural activation. More ominously, rapid delivery of these drugs to the brain creates a state of euphoria (the so‐called ‘flash’ or ‘rush’) that can lead to further drug seeking. Repeated use of these drugs changes brain circuitry and increases the likelihood of addiction. Cocaine and amphetamines are phenylisopropylamines whose stimulant properties have been known for centuries.
Visual Cascade
Authors: Baehr Wolfgang , Liebman Paul
Published: September 2006

Vision begins in the outer segments of rod and cone photoreceptor cells when visual pigments absorb light photons and become activated. Approximately 10
4
–10
5
cyclic nucleotide molecules are affected by activation of one rhodopsin molecule, so that signal generation requires enormous amplification through numerous molecules and mechanisms in the visual cascade.
Ion Channels
Authors: Lipscombe Diane
Published: September 2006

Ion channels are membrane proteins that allow ions to cross cell membranes with high speed. All cells of all organisms use ion channels to control many cellular functions.
Cerebellum: Anatomy and Organization
Authors: Hawkes Richard B
Published: September 2006

The cerebellum is a highly stereotyped cortical structure in the hindbrain of all vertebrates in which a wide variety of sensory information is brought together, primarily to aid in motor control.
Adrenergic Receptors
Authors: Malbon Craig C , Wang Hsien‐yu
Published: September 2006

Adrenergic receptors are cell‐surface receptors for two major catecholamine hormones and neurotransmitters that regulate key physiological responses, including cardiovascular and pulmonary functions. Operating via heterotrimeric G proteins, adrenergic receptors constitute one of the most intensely studied classes of membrane proteins, whose expression and function are subject to regulation at many different levels, including transcriptional, posttranscriptional and posttranslational.
Receptor Adaptation Mechanisms
Authors: Shieh Bih‐Hwa
Published: September 2006

Receptor adaptation mechanisms involve regulation of the number, sensitivity and subcellular localization of receptors that detect environmental cues and convert extracellular signals into a change of intracellular events.
Blood–Brain Barrier
Authors: Peterson Darryl R
Published: September 2006

The blood–brain barrier serves to restrict and control the movement of substances between the general circulation and brain's extracellular fluid. It participates in regulating the volume and composition of fluid surrounding the brain through specific transport processes, and thus contributes to homeostasis of the central nervous system.
Global Water Cycle
Authors: Arnell Nigel W
Published: September 2006

The global water cycle describes the circulation of water around the world from one store to another via repeated evaporation of water from land and the oceans and precipitation back to the surface. The greatest amount of water is stored in the sea, and most fresh water in ice sheets and groundwater. Much groundwater is decoupled from the current hydrological cycle, having been formed in earlier wetter periods. The ‘mobile’ part of the cycle comprises only a small proportion of the total water.
Amine Transporters
Authors: Zhen Juan , Reith Maarten EA
Published: September 2006

Amine transporters in plasma membranes mediate the transport of dopamine, (nor)adrenaline ((nor)epinephrine) and serotonin. These transporters are members of the larger Na
+
‐ and Cl
−
‐dependent neurotransmitter transporters.
Nitric Oxide as a Neuronal Messenger
Authors: Jacklet Jon W
Published: September 2006

Nitric oxide is a novel chemical agent that is used by neurons and glia in the nervous system to communicate with one another. It is used to convey and modulate information, and thereby shape behaviour.
Molecular Evolution: Nearly Neutral Theory
Authors: Ohta Tomoko
Published: September 2006

Nearly neutral theory is an extension of the neutral theory and contends that the borderline mutations, whose effects lie between the selected and the neutral classes, are important at the molecular level.
Squint (Strabismus): Mechanisms and Significance
Authors: De Larato Nicole H , Khazaeni Leila M , Volpe Nicholas J , Edmond Jane C
Published: September 2006

Strabismus, or squint, is a misalignment of the eyes. As strabismus may result in lifelong patterns of defective vision, early detection and treatment are of great importance.
Reinforcement
Authors: Butlin Roger Kenneth
Published: September 2006

Reinforcement is an increase in reproductive isolation between two populations due to natural selection that results from a reduction in the fitness of hybrids. It is a central process in many models of speciation.
Haematopoietic Growth Factors: Therapeutic Uses
Authors: Engelhardt Monika , Guo Yalin , Fetscher Sebastian , Mertelsmann Roland
Published: September 2006

Haematopoietic growth factors (HGF) belong to the family of cytokines that are glycoprotein products of activated cells. Their main biological function is to influence the intercellular cell communication and thereby cell survival, self‐renewal, proliferation, differentiation and activation at all levels of haematopoietic cell development. The clinical application of HGF was one of the main contributions in medicine and has increased the therapeutic options achieved during the last two decades of the twentieth century.
Sirenia (Dugongs and Manatees)
Authors: Domning Daryl P
Published: September 2006

Sirenia are an order of large, aquatic, plant‐eating, mostly tropical placental mammals that includes the modern seacows (dugongs and manatees) and their extinct relatives. Their nearest living relatives are the Proboscidea (elephants). Together with some extinct orders (Desmostylia and Embrithopoda), Sirenia and Proboscidea make up a group known as Tethytheria, after their likely origin along the shores of the ancient Tethys Seaway in the Old World.
Diversity of Life
Authors: Minelli Alessandro
Published: September 2006

Diversity of life (or biodiversity) is the variety of existing organisms, including their diversity at the genetic level and the full range of ecological processes in which they take part and of ecosystems to which they belong.
Palaeognathae (Flightless Birds)
Authors: Leonard Leona M , Dyke Gareth J
Published: September 2006

Current evolutionary consensus suggests that there are two broad subdivisions within living birds (Neornithes), respectively neognathous birds (Neognathae) and palaeognathous birds (Palaeognathae). Palaeognaths, the subject of this paper, are largely characterized by their primitive skull morphology. The group includes a number of well‐known flightless birds, such as the ostrich, rhea, emu, cassowaries and kiwis as well as the small, flighted tinamous.
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, which are classified into three main urkingdoms or domains; the Archaea (archaebacteria), Bacteria (eubacteria) and Eucarya (eukaryotes). While the flood of whole genome deoxyribonucleic acid (DNA) sequences from species in all the three domains have provided rich data sets to reconstruct the universal tree, it has also raised important new questions about the evolution of life. In particular, early genome evolution might have been largely shaped by the widespread occurrence of lateral or horizontal gene transfer between distantly related species from different domains.
Sauria (Lizards)
Authors: Benton Michael J
Published: September 2006

Lizards are generally small fast‐moving four‐legged slender terrestrial animals. The group of 4880 species of lizards, however, contains some exceptions: the large predatory Komodo dragon, the marine Galapagos iguana, the gliding
Draco
, various limbless forms, and burrowers.
Monotremata
Authors: Musser Anne M
Published: September 2006

Monotremes (the platypus and echidnas) are highly specialized egg‐laying mammals found today only in Australia and New Guinea.
Chiroptera (Bats)
Authors: Jones Kate E
Published: September 2006

Bats are the second largest order of placental mammals after rodents, consisting of at least 1116 species in 18 families and 202 genera. They are unique among mammals as they are the only group to have evolved truly powered flight. Bats have a worldwide distribution with extremely diverse ecologies, life histories, morphologies and unique sensory adaptations.
Nematoda (Roundworms)
Authors: Poinar George
Published: September 2006

The Nematoda are a group of nonsegmented worm‐like invertebrates that occur worldwide in a wide range of habitats.
Exceptional Preservation
Authors: Gabbott Sarah E
Published: September 2006

Exceptionally preserved fossils are rare, but are extremely important in reconstructing past life because they record details of an organism's soft tissues that are usually rapidly destroyed postmortem. Experiments on the processes of fossilization have enhanced our understanding of the biases inherent in the fossil record and allow better interpretation of morphology.
Fossil Record: Quality
Authors: Benton Michael J
Published: September 2006

There are divergent opinions about the quality of the fossil record and its ability to give a useful representation of the history of life. Extensive testing, by comparisons of the congruence of morphological and molecular phylogenies, suggests that the fossils do tell the story relatively well.
Post‐Permian Radiation
Authors: Twitchett Richard J
Published: September 2006

Events at the close of the Permian Period, led to the most severe mass extinction of the Phanerozoic. Sepkoski's ‘Palaeozoic Fauna’ suffered most; the surviving groups, more ‘modern’ in aspect, were those that would seed the post‐Permian radiation.
Industrial Melanism
Authors: Grant Bruce S
Published: September 2006

Industrial melanism refers to the evolution of dark body colours in animal species that live in habitats blackened by industrial soot. The phenomenon has been documented notably in species that hide from predators by blending in with their backgrounds.
Functional Constraint and Molecular Evolution
Authors: Forsdyke Donald R
Published: September 2006

Successful molecular evolution requires an appropriate balance between multiple functional constraints arising from selective pressures on both conventional and genome phenotypes. As more of these pressures are identified, arguments for neutral evolution weaken.
Extinction: K–T Mass Extinction
Authors: MacLeod Norman
Published: September 2006

The K–T mass extinction event occurred at the end of the Cretaceous System (K, for kreta or chalk, a common Cretaceous rock type) and the beginning of the Tertiary System (T), when approximately 40–75% of marine invertebrate species became extinct as a result of climate changes brought about by a sharp fall in global sea level, a major episode of continental flood basalt volcanism, and a large bolide (asteroid or comet) impact.
Biotic Recoveries after Extinction
Authors: Erwin Douglas H
Published: September 2006

Ecosystem recovery following mass extinctions is often more complex than a simple model of initial appearance of opportunistic forms, followed by reappearance of more specialized survivors and diversification of new forms.
Fluorescence Resonance Energy Transfer
Authors: Chhabra Deepak , dos Remedios Cristobal G
Published: September 2006

Fluorescence resonance energy transfer is a valuable tool for determining intra‐ and intermolecular distances in the range 10–100 Å. It is particularly valuable for measuring changes in molecular distance, such as conformational changes in proteins.
Mesozoa (Dicyemids)
Authors: Furuya Hidetaka
Published: September 2006

The dicyemid mesozoans are unique multicellular animals found in the kidneys of benthic cephalopod molluscs. Their life cycle is complex, but the body organization is the simplest among multicellular animals.
Kidney Development
Authors: Sariola Hannu , Bard Jonathan
Published: September 2006

In higher vertebrates, the pronephros and mesonephros are transitory embryonic organs: the permanent functional kidney is the metanephros. The metanephros is derived from intermediate mesoderm, and its differentiation is regulated by reciprocal inductive tissue interactions between the ureteric bud and the nephrogenic mesenchyme.
Ear and Lateral Line of Vertebrates: Organization and Development
Authors: Fritzsch Bernd
Published: September 2006

The mechano‐electric transducers of vertebrates (the hair cell) form the basis for two distinct sensory systems, the lateral line and the inner ear. These two sensory systems share other features such as development and the central projections to the hindbrain and are therefore grouped together as the octavo‐lateral system. This paper deals with the mechano‐sensory hair cells, the organization of sensory organs in the lateral line and inner ear, their central projection, the development of the inner ear and, to a lesser extent, the lateral‐line system as well as the system of efferent cells modifying their sensory responses.
Vertebrate Embryo: Neural Patterning
Authors: Itasaki Nobue
Published: September 2006

The primary step for constructing the central nervous system (CNS) is neural patterning, in which neural cells acquire positional identities. This process involves progressive neural induction, tissue interactions and signalling, which lead to the differentiation of functional compartments that are defined by the combinatorial expression of molecular markers.
Autonomous Cell Specification: Overview
Authors: Byrum Christine A , Wikramanayake Athula H
Published: September 2006

Autonomous cell specification is a form of specification in which the developing cell is able to differentiate (express proteins typical of the mature cell) without receiving external signals. This is possible when cytoplasmic determinants (the cytoplasmic regulatory factors necessary for specification) are partitioned into the cell during cleavage.
Bone Morphogenetic Proteins and their Receptors
Authors: van Bezooijen Rutger Leo , Heldin Carl‐Henrik , ten Dijke Peter
Published: September 2006

Bone morphogenetic proteins (BMPs) are important cell–cell signalling molecules that were first identified by their ability to induce cartilage and bone, and subsequently were shown to be multifunctional proteins. BMPs transmit their signals from membrane to nucleus through distinct combinations of type I and type II serine/threonine kinase receptors and their intracellular effectors known as Smad proteins. Transcription of target genes is regulated in a complex manner in which interactions with other signalling components and pathways define the final response.
Speciation: Genetics
Authors: Ungerer Mark C , Rieseberg Loren H
Published: September 2006

New species arise when previously interbreeding populations become isolated by reproductive barriers. These barriers are thought to originate as a byproduct of genetic divergence between geographically isolated populations; they may have a complex polygenic basis or be under simple genetic control.
Sperm–Egg Interactions: Sperm–Egg Binding in Mammals
Authors: Evans Janice P , Hardy Daniel M , Storey Bayard T
Published: September 2006

Fertilization of the mammalian egg occurs through an ordered sequence of reactions in which the sperm adheres to, then penetrates, the zona pellucida. It then binds to and then fuses with the egg's plasma membrane, so that the gametes fuse to form the zygote. The zona pellucida and egg plasma membrane are then modified after fertilization to block polyspermic fertilization. The interactions between the sperm and egg involve specific molecules on both gametes that mediate the interactions; malfunction may cause infertility.
Regeneration of Vertebrate Appendages
Authors: Ferretti Patrizia
Published: September 2006

Some vertebrates can replace complex parts of their body, a feature that is more commonly observed in invertebrates. They can perform this remarkable task because of their capacity to recruit progenitor cells and activate developmental programmes that largely parallel those used during embryogenesis.
Botulinum Toxin
Authors: Keller James E , Vann Willie F
Published: September 2006

Botulinum neurotoxin is produced by the bacteria
Clostridium botulinum
and causes the rare paralytic disease botulism. Purified toxin has gained acceptance to temporarily treat certain human diseases characterized by excessive nerve activity, and also for cosmetic treatment of facial ageing (e.g. BOTOX
®
).
Algal Cell Walls
Authors: Domozych David S
Published: September 2006

Algal cell walls comprises a diverse array of fibrillar, matrix and crystalline biochemicals. These complex extracellular coverings are formed by coordinated series of interactions between intracellular and cell surface events.
Phycology
Authors: Lewin Ralph A , Borowitzka Michael A
Published: September 2006

The study of algae is generally called ‘phycology’, from the Greek word phykos meaning ‘seaweed’. Just what algae are is difficult to define, because they belong to many different and unrelated classes including both prokaryotic and eukaryotic representatives. Broadly speaking, the algae comprise all, mainly aquatic, plants that can use light energy to fix carbon from atmospheric CO
2
and evolve oxygen, but which are not specialized land plants like mosses, ferns, coniferous trees and flowering plants. This is a negative definition, but it serves its purpose.
Crenarchaeota
Authors: Huber Harald
Published: September 2006

The Crenarchaeota, one of the meanwhile four kingdoms of the archaeal domain, consist primarily of hyperthermophiles, thriving at temperatures of up to 113°C. They have been isolated from submarine hydrothermal systems or from continental solfataric fields. So far, 3 orders with 24 genera and more than 50 species have been validly described.
Euryarchaeota
Authors: Huber Harald
Published: September 2006

The Euryarchaeota, one of the meanwhile four kingdoms (or phyla) of the archaeal domain, consists of the strict anaerobic methanogens, the extreme halophiles, the hyperthermophilic Archaeoglobales and Thermococcales, and the cell wall free Thermoplasmatales. So far, 9 orders with 56 genera and more than 190 species have been described today. This dramatic increase (especially in the amount of genera) compared to the last edition 6 years ago is based to a significant part on the reclassification of many organisms within the methanogens and the halophiles.
Catabolic Plasmids
Authors: Pemberton John M , Schmidt Radomir
Published: September 2006

Catabolic plasmids are linear or circular, accessory deoxyribonucleic acid (DNA) elements present in the cytoplasm of many bacteria from virtually every ecological niche on Earth. They confer on their hosts the ability to degrade and recycle complex, naturally occurring and synthetic molecules, including a vast array of environmental pollutants. Catabolic plasmids are the biological solution to environmental pollution.
Bromoviridae
and Allies
Authors: Scott Simon W
Published: September 2006

The family
Bromoviridae
consists of five genera:
Alfamovirus
,
Bromovirus
,
Cucumovirus
,
Ilarvirus
and
Oleavirus
. All viruses in these genera possess tripartite genomes of single‐stranded, linear, positive‐sense ribonucleic acid (RNA), in which expression of the downstream codon of the RNA3 is via a subgenomic messenger RNA (mRNA) (RNA4).
Raspberry bushy dwarf virus
(RBDV), the sole member of the genus
Idaeovirus
, shares features in common with members of the genus
Ilarvirus
and
Alfamovirus
, but possesses a bipartite genome and has not been assigned to a family. The genome of
Pelargonium zonate spot virus
(PZSV) has recently been sequenced and may be the first representative of a new genus within this family.
Bacteriophage T4
Authors: Mathews Christopher K
Published: September 2006

Analysis of molecular events following infection of
Escherichia coli
by bacteriophage T4 has revealed some of the most fundamental principles of biology, including the chemical nature of genes and mechanisms of gene expression. In addition, the phage has provided researchers with virus‐coded proteins that are continuing to serve as reagents to help fuel the biological revolution that began in 1953 with Watson and Crick and is continuing today.
Brown Algae
Authors: Lane Christopher E , Saunders Gary W
Published: September 2006

Brown algae form a natural class, the Phaeophyceae, including
c.
265 genera with 1500–2000 species. They form rich underwater forests along much of the cold and temperate coastlines of our planet.
Astroviruses
Authors: Carter Michael J , Willcocks Margaret M
Published: September 2006

Astroviruses are small ribonucleic acid (RNA) viruses, which are an important cause of diarrhoea and vomiting in the young of both humans and animals.
Rotaviruses
Authors: Palombo Enzo A , Bishop Ruth F
Published: September 2006

Rotaviruses are infectious agents, transmitted by the faecal–oral route, that cause severe gastroenteritis in the young of mammals and birds. Distinguishing features include a genome consisting of 11 segments of double‐stranded RNA, distinctive morphological appearance by electron microscopy and unique morphogenesis involving transient lipid‐enveloped particles. Morbidity and mortality rates of rotavirus diarrhoea are sufficiently high in young children throughout the world to justify vaccination to protect against this disease.
Bacterial Inclusions
Authors: Shively Jessup M , Cannon Gordon C , Heinhorst Sabine , Bryant Donald A , DasSarma Shiladitya , Bazylinski Dennis , Preiss Jack , Steinbüchel Alexander , Docampo Roberto , Dahl Christiane
Published: September 2006

Bacterial inclusions are discrete structures seen within the confines of prokaryotic cells, generally intracytoplasmic, but in some instances in the periplasmic region.
Measles Virus
Authors: Rima Bertus K , Duprex W Paul
Published: September 2006

Measles virus
is responsible for a childhood infection characterized by a maculopapular rash, dry cough, coryza, conjunctivitis and photophobia. Although mild in developed countries, the infection is associated with severe morbidity in developing countries.
Newcastle Disease Virus
Authors: Seal Bruce S , King Daniel J
Published: September 2006

Newcastle disease virus
is an economically important pathogen of poultry and other birds that has a worldwide distribution. The virus continues to pose a threat to poultry producers, and vaccination is commonly practised in many parts of the world. The virus may cause conjunctivitis in humans.
Enteroviruses
Authors: Chapman Nora M , Kim Kyung‐Soo , Tracy Steven M
Published: September 2006

Enteroviruses are commonly encountered, widely circulating, single‐stranded positive‐sense ribonucleic acid (RNA) genome human viruses that cause a variety of benign to serious diseases including myocarditis, aseptic meningitis, and possibly type 1 diabetes. Numerous cell culture and mouse models of pathogenesis are available which with molecular clones of the viral genomes, make the enteroviruses, especially the group B coxsackieviruses, an excellent system to probe molecular mechanisms of pathogenesis of common viral illnesses.
HIV Life Cycle and Inherited Coreceptors
Authors: Bukrinsky Michael I
Published: September 2006

‘Human immunodeficiency virus’ (HIV) is a lentivirus of the family
Retroviridae
, members of which cause a number of neurological and immunological diseases in humans and animals. HIV is the causative agent of the acquired immune deficiency syndrome (AIDS).
Nematophagous Fungi
Authors: Nordbring‐Hertz Birgit , Jansson Hans‐Börje , Tunlid Anders
Published: September 2006

Nematophagous fungi are microfungi that can capture, kill and digest nematodes. They use special mycelial structures, the so‐called traps, or spores to trap vermiform nematodes or hyphal tips to attack nematode eggs and cysts before penetration of the nematode cuticle, invasion and digestion.
Virus Diseases of Potatoes
Authors: Salazar LF
Published: September 2006

More than 30 different viruses are known to affect potatoes, contributing to degeneration of the crop. In response, major efforts have been made to control virus diseases by eliminating them from propagation stocks and developing resistant cultivars, procedures whose effectiveness rely on proper identification of viruses and their detection by means of sensitive and accurate virus detection technology.
Yeast Artificial Chromosomes
Authors: Bruschi Carlo V , Gjuracic Kresimir , Tosato Valentina
Published: September 2006

Yeast artificial chromosomes are shuttle‐vectors that can be amplified and modified in bacteria and employed for the cloning of very large deoxyribonucleic acid (DNA) inserts (up to 1–2 Mb pairs) in the yeastSaccharomyces cerevisiae.
Fungal Physiology
Authors: Wessels Joseph GH
Published: September 2006

Fungal physiology is concerned with activities related to growth, development and reproduction of fungi. These activities can only be understood with reference to the structure of these organisms.
Respiratory Syncytial Virus
Authors: Pringle Craig R
Published: September 2006

Respiratory syncytial virus is a ubiquitous ribonucleic acid (RNA) virus that ranks as the principal viral respiratory pathogen in infancy and as an important cause of illness and mortality in the elderly. An immunological involvement in the pathogenesis of severe disease has complicated the development of safe and effective vaccines.
Flavivirus Infections in Humans
Authors: Gould Ernest A
Published: September 2006

Flaviviruses can cause clinical disease in humans and also in animals. They are known as arboviruses, because they infect and replicate in both vertebrate and invertebrate hosts.
Viral Classification and Nomenclature
Authors: Fauquet Claude M
Published: September 2006

As any classification is essentially an arbitrary human invention it is imperative to have a unique source of virus classification. The International Committee on Taxonomy of Viruses and the Virology Division of the International Union of Microbiological Societies have been in charge of this task since 1966.
Antimicrobials against Streptococci, Pneumococci and Enterococci
Authors: Donabedian Susan , Woodford Neil , Palepou Marie‐France I , Johnson Alan P
Published: September 2006

Streptococci, pneumococci and enterococci are important bacterial pathogens of humans and can cause a range of disease. Although effective antibiotic treatments exist, threats to public health are posed by antibiotic‐resistant strains of these bacteria.