bluuebunny/crossref_metadata_2025 huggingface dataset:
Rubisco
Authors: Portis Archie R
Published: September 2006

Rubisco, formally known as ribulose‐1,5‐bisphosphate (RuBP) carboxylase/oxygenase, is the chloroplast enzyme that assimilates atmospheric carbon dioxide during photosynthesis by combining it with RuBP to form two molecules of d‐phosphoglycerate. However, Rubisco allows oxygen to react with RuBP in addition to carbon dioxide, producing phosphoglycolate, and thereby also initiates the process known as photorespiration.
Starch and Starch Grains
Authors: Geiger Donald R , Servaites Jerome C
Published: September 2006

Starch is a granular carbohydrate composed of linear and branched glucose polymers which is synthesized in plastids of leaves and storage organs. This major carbohydrate reserve, which serves for both short‐ and long‐term storage, is used when current carbon assimilation or translocation rates are insufficient.
Kranz Anatomy and the C
4
Pathway
Authors: Berry James O
Published: September 2006

C
4
photosynthesis incorporates novel leaf anatomy,
metabolic specializations, and modified gene expression. The evolution of this
pathway in some plants has facilitated their adaptation to high temperatures
or arid conditions.
Plant Stress Physiology
Authors: Rhodes David , Nadolska‐Orczyk Anna
Published: September 2006

‘Stress’ in plants can be defined as any external factor that negatively influences plant growth, productivity, reproductive capacity or survival. This includes a wide range of factors which can be broadly divided into two main categories: abiotic or environmental stress factors, and biotic or biological stress factors.
Plant Response to Water‐deficit Stress
Authors: Bray Elizabeth Ann
Published: September 2006

When plants do not receive sufficient water they are subjected to a stress called water deficit. Plants have evolved many different mechanisms to deal with the occurrence of this stress as it occurs in their environments.
Plant Salt Stress
Authors: Zhu Jian‐Kang
Published: September 2006

Plant salt stress is a condition of excessive salts in soil solution causing inhibition of plant growth or plant death.
Source–Sink Relationships
Authors: Foyer Christine H , Paul Matthew J
Published: September 2006

The term source–sink relationship refers to the integration of suger and amino acid production in photosynthesis with sugar and amino acid utlisation in growth, storage, maintenance and production.
Plant Ion Transport
Authors: Hedrich Rainer , Roelfsema M Rob G
Published: September 2006

Plant ion transport plays a key role in major physiological processes, such as nutrient uptake and redistribution, movement, growth and microbe interaction. Changes in the activity and density of ion‐pumps, channels and carriers represent essential membrane‐delimited steps in these processes.
Nitrate, Potassium and Phosphate in Plants
Authors: Lea Peter J
Published: September 2006

The kinetics of the uptake of nitrate, ammonium, potassium and phosphate by plant roots are described. The uptake mechanisms are equated to the very recent isolation and characterization of genes encoding specific membrane‐bound transporter proteins.
Photosynthesis
Authors: Ort Donald R , Whitmarsh John
Published: September 2006

Photosynthesis is the process by which higher plants, algae, and a broad class of bacteria transform light energy and store it in the form of energy‐rich organic molecules. In plants and algae, as well as some species of bacteria, photosynthesis removes carbon dioxide from the atmosphere and produces molecular oxygen. In addition there are evolutionarily more primitive bacteria that use light energy to create energy‐rich molecules, but do not split water to produce oxygen.
Chlorophyll: Structure and Function
Authors: Grimm Bernhard
Published: September 2006

Chlorophyll is the dominant pigment on Earth and serves as the light‐trapping and energy transferring chromophore in photosynthetic organisms. In recent years research has contributed enormously to a better understanding of the metabolic pathway of chlorophyll synthesis and its biochemical, biophysical and structural properties in close association with the pigment binding proteins of the reaction centre and the antenna complexes of the photosynthetic units.
Cyclic Photophosphorylation
Authors: Strotmann Heinrich , Schumann Jürgen
Published: September 2006

Cyclic photophosphorylation is the formation of ATP coupled to light‐dependent cyclic electron transport in chloroplasts without net reduction of NADP
+
.
C
3
Carbon Reduction Cycle
Authors: Raines Christine A , Lloyd Julie C
Published: September 2006

The C
3
carbon reduction cycle is the primary pathway of carbon fixation in all photosynthetic organisms, reducing CO
2
from the atmosphere to form carbohydrates; in higher plants it takes place in the chloroplast stroma.
Shikimate Pathway: Aromatic Amino Acids and Beyond
Authors: Herrmann Klaus , Entus Robert
Published: September 2006

The shikimate pathway proper is the common metabolic route to the three aromatic amino acids phenylalanine, tyrosine and tryptophan. These amino acids serve as building blocks for all proteins and as precursors for a large number of secondary metabolites.
Acid Rain
Authors: Rennenberg Heinz , Gessler Arthur
Published: September 2006

The term ‘acid rain’ describes the process of wet deposition of acidic compounds (e.g. sulfuric acid, nitrous acid and/or organic acids) in terrestrial and aquatic ecosystems. In particular, acidic deposition has different, adverse, effects on terrestrial vegetation, mainly due to soil acidification and the uptake of substances which disturb the pH levels within plant cells or produce radicals.
Plant Light Stress
Authors: Robinson Sharon A
Published: September 2006

If plants are exposed to light intensities that exceed their photosynthetic capacity, there is the potential for photodamage. Plants have therefore evolved a number of photoprotective strategies that allow them to dissipate excess energy and prevent damage to the photosynthetic apparatus.
Systemic Signalling
Authors: Yang Yinong
Published: September 2006

Systemic signalling involves a complex network of signal transduction and amplification that leads to the activation of plant defence genes and establishment of systemic acquired resistance.
Plant Defences Against Fungal Attack: Biochemistry
Authors: Funnell Deanna L , Schardl Christopher L
Published: September 2006

A wide variety of defence molecules are produced by plants either before fungal attack (preformed) or in response to an attack (induced).
Peptides: Biological Activities of Small Peptides
Authors: Mor Amram
Published: September 2006

Peptides consist of two or more amino acids linked by covalent bonds. They exert a wide range of specific functions as chemical messengers, hormones, intracellular and intercellular mediators and highly specific stimulators and inhibitors.
Proteins: Fundamental Chemical Properties
Authors: Cozzone Alain J
Published: September 2006

Proteins are important biological polymers formed from building blocks called amino acids. The three‐dimensional structure and biological activity of proteins depend on the physicochemical properties of their constituent amino acids.
Nucleotides: Uncommon, Modified and Synthetic
Authors: Switzer Christopher
Published: September 2006

Many types of modified nucleotides exist naturally or are the products of laboratory syntheses.
DNA Topology: Supercoiling and Linking
Authors: Lindsley Janet E
Published: September 2006

The topology of DNA has a major impact on its structure and reactivity. Two different aspects of DNA topology are the linkage of two single strands comprising the DNA double helix which can cause DNA supercoiling and the linkage of double helixes in the form of knots and catenanes.
The Cell Nucleus
Authors: Prasanth Kannanganattu V , Spector David L
Published: September 2006

The cell nucleus is a characteristic feature of most eukaryotic cells. It is a double‐membrane‐bound organelle that contains the genetic information of the cell packaged in the form of chromatin.
RNA Structure
Authors: Varani Gabriele
Published: September 2006

RNA molecules perform their function in living cells by adopting specific and highly complex three‐dimensional structures.
Protein–Ligand Interactions: Energetic Contributions and Shape Complementarity
Authors: Tsai Chung‐Jung , Norel Raquel , Wolfson Haim J , Maizel Jacob V , Nussinov Ruth
Published: September 2006

Protein–ligand interactions include two components: energetic contributions and shape complementarity.
Haemoglobin: Cooperativity in Protein–Ligand Interactions
Authors: Ho Chien , Lukin Jonathan A
Published: September 2006

Haemoglobin is an essential component of the circulatory system of vertebrates. Its chief physiological function is to transport oxygen from the lungs to the tissues. Haemoglobin binds oxygen cooperatively, i.e. the affinity of the protein for the first oxygen molecule is less than that for subsequent oxygen molecules. Human adult haemoglobin was among the first proteins whose complete three‐dimensional structure was determined by X‐ray crystallography.
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.
Protein–
DNA
Interactions
Authors: Rooman Marianne , Wintjens René
Published: September 2006

The control of the information stored in the genome is managed by DNA‐binding proteins, which are therefore of fundamental importance to cellular life. A wide diversity of such proteins, exhibiting various DNA interaction modes, specificities and functions, is observed in all living organisms.
Mitosis
Authors: Nigg Erich A
Published: September 2006

Mitosis is the creation of genetically identical cells from a single parental cell, involving the segregation of chromosomes to daughter cells, via a microtubule‐based structure known as the mitotic spindle. Cells first undergo nuclear division, followed by cytoplasmic division (cytokinesis). Missing or extra chromosomes (aneuploidies) can cause miscarriages, birth defects and malignant tumours.
Protein–DNA Complexes: Nonspecific
Authors: Shaner Sandra L
Published: September 2006

Nonspecific protein–DNA complexes are those that form with identical affinity to any site on a DNA molecule without regard for the sequence or structure of the DNA. Typically, the thermodynamic driving force for forming these complexes is electrostatic.
Protein–RNA Interactions
Authors: Houser‐Scott Felicia , Engelke David R
Published: September 2006

RNA–protein interactions play important roles in many biological processes. The basic features of RNA and proteins that contribute to specific recognition of RNA by proteins are currently being elucidated.
Centrosome Cycle
Authors: Bornens Michel
Published: September 2006

During the cell division cycle, duplication of the centrosome and segregation of the two daughter centrosomes dictate the assembly of the mitotic spindle and thus determine the plane of the cleavage furrow. Recent results have both modified and reinforced views about the role of the centrosome in the control of cell cycle progression in animal cells.
Cellular Thermodynamics
Authors: Wolfe Joe
Published: September 2006

Energy of various types is shared among molecules according to Boltzmann′s distribution. This simple law is used to explain aspects of the function and structure of cells, including reaction rates, electrochemical equilibria, osmosis, phase equilibria, molecular aggregation and the stability of membranes.
Pentose Phosphate Pathway
Authors: Zimmer Heinz‐Gerd
Published: September 2006

The pentose phosphate pathway occurs in the cytosol and forms a link between glycolysis and fatty acid as well as nucleotide metabolism.
Glycogen, Starch and Sucrose Synthesis
Authors: King Michael W
Published: September 2006

Glucose is an extremely important energy‐providing molecule; it is stored as a polymer – as starch in plants and as glycogen in animals. The regulation of glucose storage and utilization in humans is stringently controlled by hormones and neurotransmitters.
Glyoxylate Cycle
Authors: Beeckmans Sonia
Published: September 2006

Some organisms possess enzymes that allow the net conversion of acetyl‐CoA to succinate. This is accomplished by a special pathway, the glyoxylate cycle, which may be regarded as an anaplerotic (replenishing) pathway.
Oxidative Phosphorylation
Authors: Hansford Richard
Published: September 2006

Oxidative phosphorylation is the process by which much of the energy released by the oxidation of highly reduced foodstuffs is conserved in the phosphorylation of adenosine diphosphate to yield adenosine triphosphate. Oxidative phosphorylation occurs in the mitochondria of eukaryotes and in the cell membrane of some prokaryotes: it depends, uniquely, on the creation of a gradient of hydrogen ions across a membrane (chemiosmosis).
Ion Motive ATPases: V‐ and P‐type ATPases
Authors: Sachs George , Keeling David
Published: September 2006

Many types of species need to be transported in the working cell. Primary active ion transport across eukaryotic membranes is catalysed mainly by ion‐motive ATPases (ion pumps) of various types. The vacuolar (V‐) ATPases are almost all proton transporters evolutionarily related to the F1F0‐ ATPases; phosphorylated (P‐) ATPases represent an entirely new way of pumping ions.
Mitochondria: Structure and Role in Respiration
Authors: Krauss Stefan
Published: September 2006

Mitochondria fulfill various important roles in cellular metabolism. Of note they play a central role in cellular energy metabolism.
Photophosphorylation
Authors: Webber Andrew N
Published: September 2006

Photophosphorylation is the process through which photosynthetic organisms convert light energy to adenosine triphosphate.
Oxygen Production
Authors: Britt R David
Published: September 2006

Photosystem II utilizes visible light to drive the oxidation of water, resulting in bio‐activated electrons and protons, with the production of molecular oxygen as a byproduct. This water‐splitting reaction is carried out by a manganese cluster/tyrosine radical ensemble, the oxygen‐evolving complex.
Photosynthetic Carbon Metabolism
Authors: Portis Archie R
Published: September 2006

Photosynthetic carbon metabolism encompasses the processes by which plants and other photosynthetic organisms use the energy captured from light in the form of NADPH and ATP to convert atmospheric carbon dioxide into carbohydrates. Carbohydrates produced by photosynthesis form the base for the nutrition of all other life as well as serving as the starting materials for fibres, oils and many other natural compounds used by people.
Fatty Acid Biosynthesis
Authors: Rawlings Bernard James
Published: September 2006

Fatty acids are produced by most organisms on this planet, mainly for use in membranes or as a long‐term store of energy. While the overall organization and arrangement of the enzyme complexes varies, the underlying chemistry used to assemble fatty acids is virtually identical in every organism; the crucial step being decarboxylative addition of malonate thioesters to elongate the growing acyl chain by two carbons, followed by reduction, dehydration and reduction of the resulting 3‐oxo functionality to 3‐CH
2
, prior to further chain elongation.
Phospholipases: Degradation of Membrane Phospholipids
Authors: Fisher Aron B , Jain Mahendra
Published: September 2006

Phospholipases are interfacial enzymes that degrade phospholipids through hydrolytic cleavage. They participate in a broad spectrum of important physiological functions and pathophysiological processes through modification of phospholipids and generation of products that are potent regulators and messengers. These processes are controlled at enzymological and gene expression levels, and thus their effects range over periods of minutes to days.
Nucleotide Degradation
Authors: Simmonds H Anne , van Gennip Albert H
Published: September 2006

Nucleotide degradation is an integrated process in all human cells, being intimately linked with the pathways of nucleotide synthesis and salvage. The clinical conditions associated with defects of enzymes catalysing nucleotide degradation provide valuable insight into the importance of this network.
Uric Acid Metabolism
Authors: Skinner Kelly A , Tan Sidhartha , Parks Dale A
Published: September 2006

Nitrogenous products are continually derived from the metabolism of proteins and purine nucleotides. These nitrogenous wastes are highly toxic to an organism and necessitated the development of elaborate mechanisms for elimination of these products, which were optimally suited to the environment of the particular organism.
Sulfide: Biosynthesis from Sulfate
Authors: Verschueren Koen HG , Wilkinson Anthony J
Published: September 2006

The uptake and reduction of inorganic sulfate and its subsequent assimilation into organic biomolecules is an elaborate and energy‐consuming process. This pathway, involving many enzymes, is tightly regulated to control the production of reactive intermediates and to ensure that the flux through the pathway matches the cell's requirements for reduced sulfur.
Fibrinogen and Fibrin
Authors: Doolittle Russell F
Published: September 2006

Fibrinogen is a soluble plasma protein that is converted to fibrin polymer in response to damage to the vascular system. The clotting process is initiated when platelets aggregate at the wound site. Their disruption releases biologically active amines and a proteolytic cascade follows which culminates in the conversion of fibrinogen to fibrin. The fibrin polymer forms the matrix of the tangle of cellular and molecular substances called the blood clot.
Vitamin
K
: Structure and Function
Authors: Booth Sarah L , Saltzman Edward
Published: September 2006

Vitamin K is a cofactor specific to the vitamin K‐dependent γ‐glutamyl carboxylase and the formation of the amino acid γ‐carboxyglutamic acid (Gla). Numerous Gla‐containing proteins have been identified to date, including those involved in blood coagulation, but there are still significant gaps in knowledge about the physiological roles of many of these proteins.
Bacterial Genetics
Authors: Klotz Martin Günter
Published: September 2006

Bacteria have existed on planet Earth for more than 3.7 billion years and, since then, they have conquered virtually every life‐supporting habitat by evolving a wide variety of lifestyles through ongoing changes (by mutation and recombination) in their genomes. The understanding of how the heritable material (genotype) determines structure and function (phenotype) of bacteria is the subject of bacterial genetics.
Bacterial Membrane Transport: Organization of Membrane Activities
Authors: Maloney Peter C
Published: September 2006

Bacteria have transport systems enabling them to accumulate needed nutrients, extrude unwanted byproducts and modify their cytoplasmic content of salts so as to maintain a composition conducive to growth and development. Most bacterial transport systems resemble their counterparts in eukaryotic cells, and similar principles operate in both cell types. Because bacterial transporters are often easier to deal with experimentally, they have become important models for their eukaryotic brethren.
Bacterial Reproduction and Growth
Authors: Cooper Stephen
Published: September 2006

Bacteria growing in a suitable medium increase in number by having each cell increase in size, and then each cell divides to produce two daughter cells. The increase in cell number in a culture is therefore a result of the activity of the cell during the division cycle, between the period of birth by division and the subsequent division.
Binary Fission in Bacteria
Authors: Donachie William D
Published: September 2006

Given a suitable environment, most free‐living prokaryotic cells (including bacteria) will grow continually until, on reaching a critical size, they divide into two equal‐sized parts in a process called binary fission.
Group Translocation – PEP:PTS
Authors: Maloney Peter C , Postma Pieter
Published: September 2006

The phosphoenolpyruvate (PEP):carbohydrate
phosphotransferase
system (PTS) is a bacterial transport system that phosphorylates its carbohydrate substrates during their transport, leading to intracellular accumulation of the respective phosphoryl esters. In mixtures of carbon sources, preferential growth on PTS substrates often occurs, as the phosphorylation state of PTS proteins coordinates the activity and synthesis of enzymes of intermediary metabolism.
Glycolipids: Distribution and Biological Function
Authors: Brandenburg Klaus , Holst Otto
Published: September 2006

Glycolipids are amphiphilic components of cell membranes, composed of a hydrophilic polar sugar headgroup (backbone) and a hydrophobic apolar lipid moiety anchoring the molecule in the membrane. According to their detailed chemical structure, in particular of the sugar part, these compounds may fulfil a variety of biological functions important for many processes in life.
Tumour Immunology
Authors: Kast W Martin , Schreiber Hans , Velders Markwin P
Published: September 2006

Tumour immunology studies the role of the immune system in cancer. Knowledge of unique and tumour‐associated antigens in various tumours opens the possibility of activating the immune system against the tumours. Several immunotherapeutic approaches against different tumours are discussed.
Tumour Antigens Recognized by T Lymphocytes
Authors: Van den Eynde Benoît J
Published: September 2006

Cancer cells bear markers (antigens) that identify them to the immune system, thereby making them targets for destruction by cytolytic T lymphocytes. Therapeutic cancer vaccines designed to exploit our recently gained knowledge of the identity and structure of these antigens are now being tested in clinical trials.
Tumour Antigens Recognized by Antibodies
Authors: Scott Andrew M , Renner Christoph
Published: September 2006

Antigens are frequently overexpressed on tumours, and the
recognition of these antigens by antibodies can be used for tumour
characterization, and for potential diagnostic and therapeutic purposes.
Complement Regulatory Proteins
Authors: Meri Seppo , Jarva Hanna
Published: September 2006

Complement regulatory proteins are plasma and cell membrane molecules that regulate complement activation and protect host cells against complement damage. Certain diseases, such as hereditary angio‐oedema, membranoproliferative glomerulonephritis and paroxysmal nocturnal haemoglobinuria, are caused by complement regulator deficiency.
Hypersensitivity: Stimulatory (Type V)
Authors: Weetman Anthony P
Published: September 2006

Type V hypersensitivity is the final type of hypersensitivity in which antibodies are produced with the property of stimulating specific cell targets. The clearest example is Graves disease caused by antibodies that stimulate the thyroid‐stimulating hormone receptor, leading to overactivity of the thyroid gland.
Autoimmune Disease: Animal Models
Authors: Goverman Joan
Published: September 2006

Animal models are used for the study of multiple sclerosis, diabetes, arthritis and lupus. Induced, spontaneous and genetically manipulated animal models can be described in terms of their parallels to human disease and as tools for the development of potential therapies.
Placental Immune Defences
Authors: Arvola Marie , Mattsson Ragnar
Published: September 2006

The placenta must not only provide nutrients and take care of fetal waste products, it also needs to protect the fetus from maternal immunological attacks while at the same time transmitting maternal immunoglobulins to ensure protection against infectious agents.
Immunization of experimental animals
Authors: de Souza J Brian
Published: September 2006

Effective vaccines are urgently required for some of the major killer diseases such as human immunodeficiency virus (HIV), tuberculosis (TB), malaria and cancer. This challenge can only be realized through a better understanding of the interplay between pathogen (or tumour) and the host's immune system. While epidemiological surveys and variousin vitrostudies provide useful leads, experimental animals are powerful tools for the manipulation of the immune responsein vivoand remain central to our understanding of the body's response to infection. They afford a means of analysing the different roles played by the various components of the immune system in providing protection against disease and of devising methods of enhancing and accelerating this protection by immunization.
Chromosome Mechanics
Authors: Moore Charleen M , Best Robert G
Published: September 2006

Chromosome mechanics describes the processes of chromosome replication and behaviour as they relate to somatic cell division and gametogenesis. Mitosis produces identical diploid somatic cells, whereas meiosis produces haploid germ cells with recombination of parental alleles. Aberrations occur in these processes that include chromosomal nondisjunction leading to numerical abnormalities and unrepaired DNA damage resulting in chromosomal breakage and structural rearrangements.
Inbred Animal Strains
Authors: Kurosawa Tsutomu
Published: September 2006

There are four main genetic types of laboratory animal used in biomedical research animal breeding systems: inbred strains, mutant strains, closed colony and hybrid animals. An inbred strain is one created by at least 20 generations of brother–sister mating; members share a unique set of characteristics.
Human Chromosomes
Authors: Keitges Elisabeth , Luthardt Frederick W
Published: September 2006

Human chromosomes are the structures that house the hereditary blueprint that codes for all the traits a child will inherit from its parents. Changes in the number or structure of the chromosomes can lead to disease.
Gene Mapping: Comparative
Authors: Graves Jennifer A Marshall
Published: September 2006

The construction of gene maps of vertebrate species allows for the comparison, between species, of gene arrangement and chromosome homology. This comparative approach is useful for predicting gene position and function, and for tracing the course of genome evolution.
Chromosomal Genetic Disease: Numerical Aberrations
Authors: Robinson Wendy P , McFadden Deborah E
Published: September 2006

Numerical aberrations represent a significant proportion of chromosomal changes found in humans. These errors can occur in meiosis or mitosis and therefore be constitutive (present in all cells) or mosaic (present in some cells). They represent a significant cause of pregnancy loss as well as abnormalities found in livebirths.
Sickle Cell Anaemia
Authors: Nagel Ronald L
Published: September 2006

Sickle cell anaemia is a genetic disease, whose indispensable feature is the presence of a mutation in the beta globin gene that specifies one of the chains of haemoglobin. This mutation endows the haemoglobin with a new property: the capacity of polymerizing when deoxygenated. This mutation has several untoward consequences: haemolytic anaemia, acute chest syndrome, stroke, renal insufficiency, leg ulcers, osteonecrosis, etc. Lifespan is compromised and the only accepted treatment is hydroxyurea, which is capable of ameliorating the phenotype and extending the life of the patient.
Familial Mediterranean Fever
Authors: Babior Bernard M , Matzner Yaacov
Published: September 2006

Familial Mediterranean fever is an inherited disorder which causes episodes of severe pain and fever lasting a few days and then recurring shortly afterward. Joints, peritoneal and pleural spaces are primarily affected displaying acute inflammation and an influx of neutrophils into the inflamed area.
Pseudoautosomal Inheritance
Authors: Ellison Jay W
Published: September 2006

Certain genes on the X‐ and Y‐chromosomes exhibit a pattern of inheritance that is not sex‐linked. This pattern, referred to as pseudoautosomal inheritance, depends on genetic recombination between the X and Y.
Genetic Disease: Nonmendelian
Authors: Lightowlers Robert N , Selwood Simon P , Chrzanowska‐Lightowlers Zofia MA
Published: September 2006

The mitochondrial genome is an essential source of extranuclear deoxyribonucleic acid (DNA) in mammalian cells. Mitochondrial DNA (mtDNA) is inherited solely from the mother and encodes several polypeptides that are fundamental for cell respiration. There are many known pathogenic mutations of mtDNA which underlie a series of clinical disorders known as mitochondrial cytopathies or encephalomyopathies.
Expanding Mutations/Genetic Anticipation
Authors: Chiurazzi Pietro , Oostra Ben A
Published: September 2006

Expanding or dynamic mutations are caused by the abnormal expansion of simple repetitive sequences, which are scattered throughout the genome. The phenotypic effects will depend on the localization of the unstable sequence (exonic, intronic, in the promoter or intergenic region), on the size of the expansion, on the lack of interruptions and on the sequence of the repeat unit, which may favour the formation of secondary structures. More than 20 genetic disorders due to expanding (or ‘dynamic’) mutations have been reported to date.
Genetic Screening and Testing
Authors: Rowley Peter T , Saller Devereux N
Published: September 2006

Genetic screening is the systematic search in a population for individuals of certain genotypes. The usual purpose is to detect persons who themselves are at risk or whose offspring are at risk for a genetic disease or a genetically determined susceptibility to an environmental agent. Genetic testing is performed to determine the genotype of an individual suspected of having a mutation. This suspicion may arise because of suggestive clinical features or a genetic relationship to a person known to have the genetic abnormality in question.
Genome Mapping
Authors: Dear Paul H
Published: September 2006

Genome maps pinpoint the location of specific features on the chromosomes of an organism. They are essential tools in identifying genes responsible for diseases or traits, for comparing the genomes of different species, and for complete genome sequencing.
Fluorescence
in situ
Hybridization
Authors: Gole Leena
Published: September 2006

Fluorescence
in situ
hybridization is the detection of highly specific DNA/RNA probes which have been hybridized to their complementary sequences on morphologically preserved chromosomes or tissue sections.
Population Genetics of Modern Human Evolution
Authors: Relethford John H , Harding Rosalind M
Published: September 2006

The aim of studies in human population genetics is to determine
how mutation, genetic drift, gene flow and natural selection have generated
patterns of genetic diversity within and between populations. One application
of these studies is to questions about how modern humans evolved and the
meaning of human ‘racial’ variation.
Breast Cancer
Authors: Stamp Gordon
Published: September 2006

Breast cancer remains a major cause of morbidity and mortality worldwide and despite intensive research effort consensus agreement on management has proved difficult. This is partly a consequence of the complexity of breast cancer and the fact that this term encompasses neoplastic alterations in the breast with very differing biological backgrounds. Understanding the molecular basis of malignant progression will allow more rational treatment for the future.
Sexual Orientation
Authors: Sanders Alan R , Dawood Khytam
Published: September 2006

Sexual orientation describes what is erotically attractive to an individual and is usually consistent with sexual identity, which refers to an individual's labelling of self as heterosexual, homosexual, or bisexual; both are typically not consolidated until adolescence or later.
Autism
Authors: Piven Joseph
Published: September 2006

Autism is a syndrome characterized by impairments in social interaction and communication and by stereotyped and repetitive behaviours, with onset of symptoms usually before the age of 3 years. About 75% of affected individuals also have some intellectual impairment.
Attention Deficit–Hyperactivity Disorder
Authors: Smalley Susan L
Published: September 2006

Attention deficit–hyperactivity disorder (ADHD) is one of the most common psychiatric disorders with onset in childhood. It is characterized by persistent problems of inattention, impulsivity and hyperactivity that result in impairment in social, academic and family functioning.
Chromosome Structure
Authors: Higgins N Patrick
Published: September 2006

Genes are organized into discrete cellular structures called chromosomes that coordinate DNA replication and distribution of replicated genetic copies between two daughter cells. As vehicles of genetic transmission, chromosomes play a central role in Darwinian evolution.
Genome Inserts
Authors: Bloch Craig A
Published: September 2006

Genome inserts are DNAs, exclusive of duplications, that occur between preexisting genome sequences. They can be detected by their physical features, including the sequence motifs they contain and the size changes they introduce, or by their genetic effects. While experimental genome inserts have an important role in genome analysis, natural genome inserts participate in evolution.
Antibiotic Resistance Plasmids in Bacteria
Authors: Clewell Don B
Published: September 2006

Antibiotic resistance plasmids are bacterial extrachromosomal elements (plasmids) that carry genes conferring resistance to one or more antibiotics. They are notorious for their ability to transfer conjugatively between bacterial species and are significantly involved in the emergence and dissemination of multiple drug resistance.
RNA
–
DNA
Molecules
Authors: Chen Yahua , Reddy Ramanchandra
Published: September 2006

RNA–DNA chimaeric molecules are important intermediates in many essential biological processes, including DNA replication and reverse transcription by retroviruses.
TransferRNAin Decoding and the Wobble Hypothesis
Authors: Tuite Mick F
Published: September 2006

The translation of the genetic code stored in messenger RNA requires significantly fewer tranfer RNAs than there are codons. This is achieved through an increased flexibility in the allowable base‐pair interactions between the mRNA and tRNA involving the third position of the codon. The rules governing the allowable base‐pair interactions were originally summarized in Crick's ‘wobble hypothesis’.
Gene Expression: Frameshifting
Authors: Atkins John F , Gesteland Raymond F
Published: September 2006

Ribosomes shift reading frames at high levels at specific places in the decoding of a minority of messenger RNAs in probably all organisms. This frameshifting serves a regulatory function or is used to synthesize more than one product from a coding sequence.
Site‐specific Recombination in Chromosome Function
Authors: Sherratt David J
Published: September 2006

Site‐specific recombination leads to the integration, deletion or inversion of defined DNA segments by conservative breakage–rejoining reactions at defined recombination sites. It functions to integrate and excise extrachromosomal elements into and out of genomes, to maintain circular replicons at the correct copy number in a monomeric state, and to mediate inversion gene switches.
Caenorhabditis elegans: Determination of Germ Cell Fate
Authors: Schierenberg Einhard
Published: September 2006

Considerable differences exist between germ cells and somatic cells with respect to developmental programmes and control of gene expression. During germ cell formation several decisions have to be made. Recent progress has helped to elucidate the control of developmental choices, such as those between proliferation or differentiation, mitotis or meiosis, life or programmed cell death, sperm or oocyte.
DrosophilaEmbryo: Cell Signalling and Segmental Patterning
Authors: Vincent Jean‐Paul , Alexandre Cyrille
Published: September 2006

Expression of the primary segment polarity geneswinglessandhedgehogestablishes a signalling centre at each parasegment boundary of theDrosophilaembryo. As a result, epidermal cells within each segment acquire a specific fate and polarity along the anterior–posterior axis.
Caenorhabditis elegans
Embryo: Establishment of Asymmetry
Authors: Basham Stephen E , Rose Lesilee S
Published: September 2006

In
Caenorhabditis elegans
anterior/posterior
asymmetry is established in the one‐cell embryo in response to the
sperm's position. Polarity proteins become localized in cortical
domains and function to produce asymmetric expression patterns of regulators
of developmental fate.
Drosophila
Retinal Patterning
Authors: Spencer Susan , Brachmann Carrie , Cagan Ross
Published: September 2006

The
Drosophila
retina is a compound apposition eye
composed of some 750 self‐contained eye units with lens, retina and
photoreceptors. Study of the
Drosophila
retina is useful in
understanding the general problems of cell cycle regulation, local cell
signalling, expression of determinative factors, control of programmed cell
death and rearrangement of cells within epithelia.
Sea Urchin Embryo: Specification of Cell Fate
Authors: Angerer Robert C , Angerer Lynne M
Published: September 2006

Specification of cell fate in sea urchin embryos involves
initial asymmetric distribution of maternal molecules that establish vegetal
and nonvegetal domains of transcription activity. Subsequently, fates of most
blastomeres are regulated by cell–cell interactions involving signalling
ligands and cell surface receptors.
Geological Time: History of Ideas
Authors: Bowler Peter J
Published: September 2006

Early estimates of the Earth's age were restricted by literal interpretations of Genesis, but the geological time scale had been greatly extended by the early nineteenth century. Calculations by physicists gave rise to very limited estimates of the Earth's age in the late nineteenth century, and it was only after the discovery of radioactivity that it became possible both to extend the scale of geological time and develop techniques for providing exact dates.
Evolution: History
Authors: Bowler Peter J
Published: September 2006

The modern theory of evolution was founded by Charles Darwin,
but an overview of the history of evolutionism shows that ideas of the
transformation of species predated Darwin, and that even following the
publication of Darwin's
Origin of Species
in 1859, a complex
series of developments was needed to create the genetical theory of natural
selection accepted by most biologists today.
Phylogeny and Stratigraphy Comparison
Authors: Wagner Peter
Published: September 2006

Phylogenetic relationships among taxa can be estimated in a number of ways. Given known fossil records, phylogenetic estimates implicitly hypothesize the latest possible origination times of taxa. These hypotheses can be used to evaluate the quality of the fossil record. Alternatively, these hypotheses can be tested using various methods in order to test the assumptions yielding the initial phylogenetic estimate.
Cladistics
Authors: Wilkinson Mark
Published: September 2006

Cladistic methods aim to reconstruct the branching pattern of the Tree of Life. Cladistic classification is a philosophy of classification based only on cladistic relationships.
Fossil Record
Authors: Benton Michael J
Published: September 2006

Fossils are the remains of plants and animals that once lived. Quality of preservation ranges from complete to traces of hard parts only, and it is important to consider how this incompleteness affects understanding of past life.
Urochordata (Tunicates)
Authors: Jefferies Richard
Published: September 2006

The Urochordata are a subphylum of the Chordata comprising marine organisms such as the benthic ascidians and the pelagic appendicularians, salps, doliolids and pyrosomes.
Cephalochordata (Lancelets)
Authors: Jefferies Richard PS
Published: September 2006

The Cephalochordata constitute one of the three traditionally recognized subphyla of the Chordata, the other two being the Tunicata (Urochordata) and the Craniata (including the Vertebrata). They are also known as Acraniata or lancelets. There are only two extant genera,
Branchiostoma
(amphioxus) and
Epigonichthys
(
Asymmetron
).
Vertebrata (Vertebrates)
Authors: Janvier Philippe
Published: September 2006

The Vertebrata, or vertebrates, are all animals which possess a skull enclosing the brain and sensory organs. Most vertebrates (except for hagfish) also possess a vertebral column (hence their name).
Placodermi (Armoured Fishes)
Authors: Goujet Daniel F
Published: September 2006

Placoderms are a group of fossil true jawed fishes restricted to the Middle Palaeozoic period (Silurian and Devonian). They were the dominant forms in the seas of this time with more than 300 species. They show adaptations to various modes of life including the first active vertebrate predators and numerous bottom‐feeders.
Osteichthyes (Bony Fishes)
Authors: Hitchin Rebecca
Published: September 2006

Osteichthyes are characterized by the presence of a well‐ossified bony internal skeleton, bony scales and fins that are supported by bony rods.
Sauria (Lizards)
Authors: Benton Michael J
Published: September 2006

Lizards are generally small fast‐moving four‐legged slender terrestrial animals. The group of 3440 species of lizards, however, contains some exceptions: the large predatory Komodo dragon, the marine Galapagos iguana, the gliding
Draco
, various limbless forms, and burrowers.
Serpentes (Snakes)
Authors: Lee Michael SY
Published: September 2006

Snakes are a diverse group of long‐bodied, limb‐reduced reptiles descended from lizards. They are of scientific, ecological and medical importance.
Crocodylia (Including Crocodiles and Alligators)
Authors: Densmore Llewellyn D
Published: September 2006

The order Crocodylia contains the sole reptilian survivors of the Archosauria, which also included the dinosaurs. Understanding the biology, natural history and evolution of the living crocodylians is critical to appreciate fully their place in nature.
Dinosauria (Dinosaurs)
Authors: Carpenter Kenneth
Published: September 2006

Dinosaurs are a group of extinct vertebrates that lived from 230 to 65 million years ago.
Aves (Birds)
Authors: Cunnningham Emma JA
Published: September 2006

The class Aves is the part of the animal kingdom containing all known species of birds, past and present. Their basic biology, evolutionary history and general ecology are key to understanding their success in the environment today.
Mesozoic Birds
Authors: Chiappe Luis M
Published: September 2006

Mesozoic birds are those birds that lived between 150 and 65 million years ago, during the last half of the age of large dinosaurs. During this 85 million years of known history, the Mesozoic birds evolved a wide range of basic body forms and lifestyles.
Neognathae (Typical Birds)
Authors: Andors Allison V
Published: September 2006

The Neognathae comprise a superorder of flying, or secondarily flightless, birds in the class Aves and subclass Neornithes. They are characterized by possession of a keeled sternum and of a bony palate of the neognathous type.
Eutheria (Placental Mammals)
Authors: Archibald J David
Published: September 2006

Eutheria includes one of three major clades of mammals, the extant members of which are referred to as placentals.
Lagomorpha (Rabbits, Hares and Pikas)
Authors: Montuire Sophie
Published: September 2006

Lagomorphs comprise the pikas, hares and rabbits. The members of this order have a head and body length between 0.125 and 0.75 m, and adults weigh from 0.1 to 5 kg. All are terrestrial. Pikas are mostly diurnal whereas rabbits and hares are active mainly in the evening and night. They can be strong runners.
Macroscelidea
Authors: Montuire Sophie
Published: September 2006

Macroscelids are known as elephant shrews because of their long and narrow snouts. Living exclusively in Africa, they are small mammals with a head and body length between 95 and 315 mm, and tail length between 80 and 265 mm.
Mesozoic Mammals
Authors: Rougier Guillermo W
Published: September 2006

Mesozoic mammals are those mammals that lived during the Mesozoic era, from 245 to 65 million years before the present. The lineage leading to mammals, Synapsida, is truly ancient; it branched off the trunk leading to reptiles at least 350 million years ago.
Primates (Lemurs, Apes, and Monkeys)
Authors: Hartwig Walter C , Rosenberger Alfred L
Published: September 2006

Primates are an order of mammals characterized by a generalized arboreal anatomy and relatively large brains. Primates are found throughout the tropics and temperate latitudes of the world and are among the most endangered of all mammalian orders.
Cetacea (Whales, Porpoises and Dolphins)
Authors: Fordyce R Ewan
Published: September 2006

Cetaceans (whales and dolphins) are streamlined aquatic mammals that spend all their lives in water. They include the largest living animals. Because their aquatic lifestyle makes them difficult to study, we know less about cetaceans than about most other groups of mammals.
Proboscidea (Elephants)
Authors: Shoshani Jeheskel
Published: September 2006

Proboscidea – the living elephants and their fossil relatives – are of ungulate origin, dating to the late Palaeocene of northeast Africa and spread to all continents except Australia and Antarctica. The earliest proboscideans were characterized by the presence of a prominent and hooked coracoid process on the scapula (shoulder blade), and a medial process on the astragalus (ankle bone). Advanced proboscideans have pneumatized bones in the cranium, a developed proboscis (trunk), horizontal (rather than the usual vertical) tooth displacement, tusks that exhibit Schreger pattern in a cross‐section, and possess a temporal gland. The estimated number of fossil and living species and subspecies of proboscideans is 165, of which only three are alive today.
Sirenia (Dugongs and Manatees)
Authors: Domning Daryl P
Published: September 2006

The Sirenia is 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), the 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.
Placozoa
Authors: Thiemann Otavio H
Published: September 2006

Placozoa is a phylum of multicellular animals that are only a few mm in diameter and are continuously changing shape by forming folds at the dorsal surface. Its natural habitat is seawater.
Porifera (Sponges)
Authors: Bergquist Patricia R
Published: September 2006

Porifera, or sponges, are primitive Metazoa. They are multicellular but have no developed tissue organization, utilizing independent cellular activity to carry out all body functions. They are a successful group in ancient and recent aquatic environments with origins in pre‐Cambrian times.
Cnidaria (Coelenterates)
Authors: Shostak Stanley
Published: September 2006

Cnidaria (Gr.,
cnidae
, nettle) is a phylum of mostly marine Metazoa distinguished by cnidocysts, subcellular encapsulated tubules capable of everting and, in some cases, discharging venom. Sexual reproduction results in solid planula embryos that develop into columnar polyps. Asexual reproduction results in clones of polyps, polypoidal colonies or disk‐shaped to bell‐shaped sexual medusas (jellyfish).
Ctenophora (Sea Walnuts and Comb Jellies)
Authors: Harbison GR
Published: September 2006

The Ctenophora are a small group of marine invertebrates most of whom have eight longitudinal rows of fused macrocilia, called comb rows, which they use to propel themselves through the water.
Platyhelminthes (Flatworms)
Authors: Rohde Klaus
Published: September 2006

The Platyhelminthes are a group of nonsegmented invertebrates that occur worldwide in a wide range of habitats; more than half of the species are parasitic.
Rotifera
Authors: Wallace Robert Lee
Published: September 2006

Rotifera are minute, bilaterally symmetrical, unsegmented animals that live predominantly in freshwaters. The phylum name (Latin,
rota
, wheel;
ferre
, to bear) was first used by Cuvier in 1798; this refers to the anterior end which, in many species, resembles a rotating wheel due to the sequential beat of its cilia.