bluuebunny/crossref_metadata_2025 huggingface dataset:
Myelin and Action Potential Propagation
Authors: Rasband Matthew N
Published: September 2006

The high action potential conduction velocities achieved in some vertebrate axons are a consequence of myelin, an insulating sheath made by glial cells, and clustered sodium ion (Na
+
) channels found at regularly spaced gaps in the myelin sheath.
Spinal Reflexes
Authors: Burke Robert E
Published: September 2006

Spinal reflexes are automatic and stereotyped behaviours that are integrated into a hierarchical control system. Reflex actions are controlled by the interaction of inputs that converge on reflex pathway neurons.
Synaptic Integration
Authors: Williams Stephen R , Stuart Greg J
Published: September 2006

Neurons in the brain receive thousands of synaptic inputs from other neurons. Synaptic integration is the term used to describe how neurons ‘add up’ these inputs prior to the generation of a nerve impulse, or action potential.
Synaptic Vesicle Traffic
Authors: Dunlap David , Valtorta Flavia , Fesce Riccardo
Published: September 2006

Signals travel along nerve cell membranes as electrical impulses but are transmitted from one neuron to other neurons and/or effector cells by the release of neurotransmitter across a small intervening space (synaptic cleft). Such neurotransmitter is contained within synaptic vesicles that fuse with the plasma membrane when it depolarizes, to release their contents. The
vesicles are then rapidly retrieved and refurbished to sustain further synaptic activity.
Thalamus
Authors: Steriade Mircea
Published: September 2006

The thalamus is a collection of nuclei deep within the brain acting as a highly sophisticated relay station between the cerebral cortex and brainstem.
Topographic Maps in the Brain
Authors: Petersen Rasmus S , Diamond Mathew E
Published: September 2006

A topographic map is a representation in which spatial location of activity within a neuronal array encodes some important feature of a stimulus. Such maps are a fundamental strategy of sensory processing in mammalian species
Touch
Authors: Gardner Esther P
Published: September 2006

Touch is defined as direct contact between two physical bodies. In neuroscience, touch describes the special sense by which contact with the body of an organism is perceived in the conscious mind. Some touch involves an active motor component – stroking, tapping or pressing – whereby a part of the body is moved against another surface. The sensory and motor components of touch are intimately connected anatomically in the brain, and are important functionally in guiding behaviour.
Vestibular System
Authors: Dieringer Norbert
Published: September 2006

Specialized mechanoreceptors, known as hair cells, detect and encode angular and linear components of head movements as well as the orientation of the head with respect to gravity. These signals activate stabilizing somatic and autonomic reflexes, evoke a perception of self motion and can trigger nausea and dizziness.
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. Some 10
4
to 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.
Visual System
Authors: Van Hooser Stephen D , Nelson Sacha B
Published: September 2006

Humans and many other animals obtain much of their information about the world through their eyes. Patterns of light are transformed into nerve impulses in the retina and visual information is processed by nerve cells in the primary visual cortex. In the human brain, about one‐half of the cerebral cortex is dedicated in some way to the processing of visual information.
Benzodiazepines
Authors: Möhler Hanns
Published: September 2006

Benzodiazepines are a group of drugs with wide application as
tranquillizers, hypnotics, muscle relaxants and anticonvulsants. They act by
enhancing γ‐aminobutyric acid (GABA)ergic synaptic inhibition in the
brain.
GABA
B
Receptors
Authors: Kaupmann Klemens , Froestl Wolfgang , Bettler Bernhard
Published: September 2006

γ‐Aminobutyric acid (GABA), the principal inhibitory neurotransmitter in the brain, signals through ionotropic (GABA
A/C
) and metabotropic (GABA
B
) receptor systems. GABA
B
receptors modulate synaptic transmission and are structurally related to the metabotropic glutamate receptors. The properties of the recently cloned GABA
B
R1a and ‐b receptors are compared to brain GABA
B
receptors.
Glutamatergic Synapses: Molecular Organization
Authors: Sheng Morgan , Lin Jerry W
Published: September 2006

Glutamatergic synapses, which comprise the majority of excitatory synapses in the mammalian central nervous system, function by presynaptic release of glutamate onto postsynaptic glutamate receptors. At the postsynaptic site, the molecular interactions between glutamate receptors and various intracellular proteins suggest an intimate relationship between synaptic structure and function, and may provide insight into the mechanisms of synaptic plasticity that underlie learning and memory.
Metabotropic Glutamate Receptors
Authors: Doherty AJ , Collingridge GL
Published: September 2006

The metabotropic glutamate receptors are a family of G protein‐coupled receptors widely distributed in the central nervous system, acting to modulate synaptic function through interactions with other receptors, signalling mechanisms and (potentially) gene expression.
Nicotinic Acetylcholine Receptors in Muscle
Authors: Hucho Ferdinand
Published: September 2006

Acetylcholine is the neurotransmitter carrying the excitatory signal at the neuromuscular endplate from the presynaptic to the postsynaptic side across the synaptic cleft. Together with acetylcholinesterase, the nicotinic acetylecholine receptor regulates the intensity and duration of the signal at the muscle.
Myasthenia Gravis
Authors: Sanders Donald B
Published: September 2006

Myasthenia gravis is an autoimmune disease in which weakness results from an immunological attack against the nerve–muscle junction. It is the most well understood autoimmune disease, and knowledge of its cause and treatment has broad relevance to many diseases of more common occurrence.
Nicotinic Acetylcholine Receptors
Authors: Lindstrom Jon
Published: September 2006

Nicotinic acetylcholine receptors are receptors for the neurotransmitter acetylcholine in which binding of acetylcholine triggers the opening of a transmembrane channel through the centre of the receptor protein. Nicotinic receptors are part of a gene superfamily of transmitter gated ion channels that includes receptors for glycine and gamma amino butyric acid. Nicotinic receptors are distinct from muscarinic acetylcholine receptors, which are part of a gene superfamily of metabotropic G‐protein linked receptors.
Synapse Formation
Authors: Kidokoro Yoshiaki
Published: September 2006

The synapse is a special device in the brain for transmitting signals from one neuron to another or to a muscle cell, and is the major site for signal modification. Its elaborate structure is formed in multiple steps during development. Some of these steps may be repeated during plastic changes in the brain, such as memory and learning.
Parkinson Disease
Authors: Hornykiewicz Oleh
Published: September 2006

Parkinson disease is a common, chronic, relentlessly progressive neurodegenerative basal ganglia disorder of movement, consequent to incessant loss of the dopamine‐containing neurons of the substantia nigra. Correction with
l
‐dihydroxyphenylalanine (
l
‐DOPA) of the severe brain dopamine deficit characteristic for Parkinson disease represents the most efficacious treatment of this disorder.
Cellular Neuromodulation
Authors: Wilson Gisela F
Published: September 2006

Neuromodulation confers context‐sensitive flexibility to the
signalling properties of neurons. The neuron is the central point of
integration for an array of extracellular signals, and the output of the
neuron, namely electrical activity and neurotransmitter release, is a function
of the biochemical integration process. Remarkably, the choice between
behaviours in different environmental or physiological contexts can often be
ascribed to the biochemical processing that occurs at the level of a single
neuron.
Memory in Fruit Flies and Nematodes
Authors: Tanchuk Tracy L , Galloway Jennifer A , Peters Kevin R , Rankin Catharine H
Published: September 2006

A change in the behaviour of an organism that results from that individual's exposure to stimuli/events in the environment.
Drosophila melanogaster
and
Caenorhabditis elegans
have been the focus of much research in the areas of learning and memory.
Neurotransmitter Receptors in the Postsynaptic Neuron
Authors: Stephenson F Anne , Hawkins Lynda M
Published: September 2006

The neurotransmitter receptor proteins are integral components
in the communication between adjacent cells of the nervous system, spanning
the width of the postsynaptic membrane and protruding into the synaptic cleft
and cell cytoplasm. They mediate the effects of neurotransmitters between
adjacent neurons.
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 in the nervous system to communicate with one another. It is used to convey and modulate information, and thereby shape behaviour.
Bacterial Cells
Authors: Beveridge Terry J
Published: September 2006

Bacteria are prokaryotes and therefore have a simple cell structure. There is no nucleus and genetic material is free within the cytoplasm. The two fundamental types of bacteria – Gram‐positive and Gram‐negative – have different cell wall structures.
Bacterial Flagella
Authors: Morgan David Gene , Khan Shahid
Published: September 2006

Flagella are membrane‐embedded, filamentous organelles that are utilized by bacteria to move through liquid or over semisolid media. Propulsion is driven by flagellar rotation, which is energized by the flux of protons or other ions down their electrochemical gradients rather than by ATP hydrolysis.
Bacterial Inclusions
Authors: Shively Jessup M , Baker Stefanie H , Bradburne Christopher E , Bruce‐Carver Megan
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.
Bacterial Ribosomes
Authors: Frank Joachim , Agrawal Rajendra K
Published: September 2006

Ribosomes are complex ribonucleoproteins that provide the platform for protein biosynthesis in all organisms.
Myxospores
Authors: Hartzell Patricia L , White David J
Published: September 2006

Myxospores are spores produced by the myxobacteria, a subset of gliding bacteria that aggregate to form multicellular structures that contain the differentiated spores.
Algae: Phylogeny and Evolution
Authors: Moestrup Øjvind
Published: September 2006

Ideas on the phylogeny and evolution of the algae are presently based on a combination of ultrastructural and molecular data. Following the discovery that the chloroplasts of eukaryotic algae arose after one or more symbiotic events, the term algae is now used as a colloquial term for primitive plants, including both prokaryotic and eukaryotic species.
Algal Cell Walls
Authors: Domozych David S
Published: September 2006

Algal cell walls constitute a rich array of fibrillar, matrix and crystalline chemicals. These complex extracellular coverings are formed by complex interactions of intracellular and cell surface events.
Algal Chloroplasts
Authors: Purton Saul
Published: September 2006

A great diversity of chloroplasts is found amongst the various algal groups. This diversity is the result of an intriguing evolutionary process that involved the acquisition of chloroplasts by different eukaryotic organisms.
Algal Metabolism
Authors: Raven John A
Published: September 2006

Algal metabolism concerns the biochemical and transport processes by which algae take up nutrients and convert them into the materials needed for growth, reproduction and defence of the organisms.
Algal Symbioses
Authors: Douglas Angela E
Published: September 2006

Algae (including cyanobacteria) enter into symbioses with protists, animals, fungi and plants. They contribute to the nutrition of their partners through photosynthetic carbon fixation and, for cyanobacteria, nitrogen fixation.
Diatoms
Authors: Theriot Edward C
Published: September 2006

Diatoms are single‐celled autotrophic organisms that have highly ornate siliceus walls. They are a very diverse group with many species being of significant ecological importance.
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 dioxide 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.
Alkaliphiles
Authors: Horikoshi Koki
Published: September 2006

Alkaliphiles grow optimally or very well at pH values above 9, often between 10 and 12, but cannot grow, or grow only slowly, at more neutral pH values. The enzymology, physiology, ecology, molecular biology and genetics of alkaliphiles as well as industrial applications of these microorganisms have been investigated extensively and several enzymes have been put to use on an industrial scale.
Bacterial Taxis
Authors: Armitage Judith P
Published: September 2006

Bacteria swim by rotating semirigid helical flagella. They can swim at speeds of many body lengths per second. They can sense a wide range of environmental signals; chemical changes, light, oxygen levels, changes in temperature and even the earth's magnetic field. By temporally sampling their environment they bias their overall direction of swimming to an optimum environment for growth.
Biogeochemical Cycles
Authors: Ehrlich Henry L , Oremland Ronald S , Zehr Jonathan P
Published: September 2006

The biosphere harbours large quantities of the elements essential to life, but the largest portion is tied up as minerals and sediments. Dead biomass and some of the nutrients immobilized in rocks and sediments are made available to living organisms through recyling (biodegradation) by microbes.
Ascomycota
Authors: Eriksson Ove E
Published: September 2006

The ascomycetes, the spore sac fungi, are accommodated in the phylum Ascomycota, the largest of the four phyla of the true Fungi. The life cycle (holomorph) of an ascomycete may consist of a sexual stage (teleomorph) producing meiospores (ascospores) in spore sacs (asci, sing. ascus) and/or one or several asexual stages (anamorphs) producing mitospores (conidia). Some ascomycetes lack fruit bodies (yeasts, etc.), but most form asci in ascomata. Some conidial fungi (the coelomycetes) produce conidia in conidiomata, but others (the hyphomycetes) lack fruit bodies.
Basidiomycota
Authors: Watkinson Sarah C
Published: September 2006

Basidiomycetes are the group of fungi that reproduce and are dispersed by means of basidiospores produced from basidia, specialized cells in which meiosis occurs. The basidiomycetes are one of the two most advanced groups of the kingdom Fungi, the other being the ascomycetes. The two groups probably originated from a common ancestor during the evolution of life on land. Basidiomycetes and ascomycetes are collectively known as ‘higher’ or ‘septate’ fungi, and share many features that distinguish them from the simpler and more primitive aseptate lower fungi, Zygomycota and Chytridiomycota.
Budding
Authors: Goebl Mark G , Schweitzer Kelly
Published: September 2006

Budding is a form of asexual reproduction utilized by unicellular fungi known as yeast. A small protuberance is formed on the cell wall that grows in size until it is almost the size of the original yeast cell, forming a narrow neck between the two cells. Cytokinesis then occurs at the neck between the two cells.
Deuteromycetes (Fungi Imperfecti)
Authors: Gams Walter , Seifert Keith A
Published: September 2006

The deuteromycetes are an artificial assemblage of asexual stages of ascomycetes and basidiomycetes, classified together with asexually reproducing fungi that do not form sexual structures but are assumed to be related to those that do.
Fungal Cells
Authors: Mishra Nawin C
Published: September 2006

Fungal cells have been used to produce a variety of useful items such as bread, beer, cheese and antibiotics. The study of fungal cells has also facilitated advances in medicine and agriculture.
Fungal Cell Walls
Authors: Ross Ian K
Published: September 2006

Fungal cell walls are paradoxical combinations of unyielding rigidity and soft elastic plasticity, inert protective covers and dynamic regulators of metabolism and differentiation, impenetrable hydrophobic layers and freely secreting tips, about which all too little is understood.
Fungal Ecology
Authors: Hawksworth David L
Published: September 2006

Fungal ecology is the relationship between fungi, the environment, and other organisms.
Fungal Pathogens of Humans
Authors: Mitchell Thomas G
Published: September 2006

Fungi may cause human disease by establishing an infection, inducing an allergic response or producing a toxin. Most pathogenic fungi are free‐living saprophytes and are only incidental pathogens of humans. The mycoses or fungal infections with the highest prevalence are caused by the few fungi that are part of the normal microbial flora or that are highly adapted for survival on the human host. There are a number of strategies for their diagnosis and management.
Fungal Metabolites
Authors: Moss Maurice O
Published: September 2006

Fungal metabolites are products of secondary metabolism; some of them have an impact on human wellbeing.
Fungal Pathogens of Plants
Authors: Alfen Neal K Van
Published: September 2006

Fungi are the most important of the various groups of pathogens that attack plants. Our agricultural fields, forests, grasslands and urban landscapes are diminished in economic value and beauty by this important group of plant pathogens. Some fungal diseases, such as chestnut blight, make it impossible for hosts such as the American chestnut to grow where the disease is present.
Hyphal Growth
Authors: Trinci Anthony PJ , Wiebe Marilyn G , Robson Geoffrey D
Published: September 2006

Hyphal filaments are the units that comprise a fungal mycelium. It is the efficient growth of these hyphal filaments that plays a crucial role in fungal colonization of a substrate.
Mushrooms and Mushroom Cultivation
Authors: Chang Shu‐Ting
Published: September 2006

A mushroom is a macrofungus with a distinctive fruiting body, which can be found either above ground (epigeous) or below ground (hypogeous), large enough to be seen with the naked eye and to be picked by hand. Cultivation of mushrooms starts from spawn, which is used to inoculate substrate. Under optimum conditions, mushrooms can be harvested from 10 days to 6 months after spawning depending upon the strains of species used.
Mycoses
Authors: Kobayashi George S
Published: September 2006

Mycoses are the infections and diseases caused by fungi.
Mycorrhiza
Authors: Read DJ
Published: September 2006

Mycorrhizas are multifunctional symbiotic associations between fungi and the roots of plants. In most cases, as a result of the symbiosis, the fungi obtain the sugars required to enable their growth and reproduction. The plants, in turn, may gain increased supplies of nutrients, which are captured from soil by the fungi, as well as enhanced resistance to disease and toxicity.
Mycotoxins
Authors: Bhatnagar Deepak , Ehrlich Kenneth C , Chang Perng‐Kuang
Published: September 2006

Mycotoxins are natural fungal products, the ingestion of which can evoke toxic responses in higher vertebrates and other animals. Many have been characterized and show significant diversity in their chemical structures and biological activity.
Fungal Xerophiles (Osmophiles)
Authors: Hocking Ailsa D
Published: September 2006

Xerophilic fungi are yeasts and moulds that are capable of growth at or below a water activity (
a
w
) of 0.85. These microorganisms have developed physiological mechanisms that enable their biochemical pathways to function in concentrated environments. As a group they are extremely important in the spoilage of many processed foods and stored commodities.
Fungal Spores
Authors: Moore‐Landecker Elizabeth
Published: September 2006

Fungi reproduce, sexually or asexually, by forming spores, which are cells that are specialized for dispersal and subsequent germination to produce the somatic phase of a new fungal generation.
Yeasts
Authors: Phaff Herman J
Published: September 2006

Yeasts are a group of eukaryotic fungi with a well‐defined cell wall whose vegetative growth is either entirely unicellular or a combination of hyphal and unicellular reproduction.
Zygomycota
Authors: Moore‐Landecker Elizabeth
Published: September 2006

The division
Zygomycota
is an important and diverse group of fungi, containing two classes, the Zygomycetes and Trichomycetes.
Actinomyces
spores
Authors: Locci Romano
Published: September 2006

Among bacteria, actinomycetes are a morphologically distinct group that forms multinucleated filaments instead of single cellular units. Within this quantitatively small realm however, the organisms are characterized by a wide range of morphological patterns of development, the variety of dispersal propagules (spores or conidia) produced and their genesis.
Archaeal Cell Walls
Authors: König Helmut
Published: September 2006

Archaea represent the third domain of life with the Bacteria and Eukarya. They have developed different types of cell envelopes.
Archaeal Membrane Lipids
Authors: Patel Girish B , Sprott G Dennis
Published: September 2006

Membrane lipids of Archaea are unique and distinct from those found in Eukarya and Bacteria. The polar lipids consist of branched phytanyl chains, 20 to 40 carbons in length and usually saturated, which are attached via ether bonds to the glycerol carbons at the
sn
‐2,3 positions. The polar lipids of Archaea can be used to make liposomes (closed vesicles) which have characteristics that are useful for applications in biotechnology.
Archaeal Flagella
Authors: Jarrell Ken F , Bayley Douglas P , Correia Jason D , Thomas Nikhil A
Published: September 2006

The motility apparatus of the Archaea, the archaeal flagellum, is a unique structure distinct from the bacterial equivalent in composition and structure as shown by studies of flagellin proteins and flagellin genes. In spite of this, there are similarities between the archaeal and bacterial chemotaxis systems.
Endosymbionts
Authors: Jeon Kwang W
Published: September 2006

Endosymbionts are smaller symbiotic partners living inside a host organism, and they may live within the host's cells (intracellular) or outside cells (extracellular) in a multicellular host. A symbiotic relationship may be parasitic (one partner harming the other), commensal (usually not affecting each other), or beneficial (unilaterally or mutually).
Extremophiles
Authors: Antranikian Garabed
Published: September 2006

Extremophiles are microorganisms that are adapted to living in extreme conditions of temperature, pressure, pH or salt concentration. Their application to industrial processes is opening up a new era in biotechnology.
Extreme Thermophiles
Authors: Wiegel Juergen , Canganella Francesco
Published: September 2006

Extreme thermophiles are those microorganisms whose optimal growth temperature is between 65 and 85°C.
Rumen
Authors: Mackie Roderick I , McSweeney Christopher S , Aminov Rustem I
Published: September 2006

The rumen is a large pregastric fermentation compartment (foregut) which maintains a diverse but concentrated population of anaerobic bacteria, protozoa and fungi that are responsible for a variety of degradative and fermentative reactions. During this process biodegradable organic matter, mainly plant cell wall polymers, are converted into volatile fatty acids and microbial biomass which supply energy and protein to the host (ruminant) animal.
Adeno‐associated Viruses
Authors: Xiao Xiao
Published: September 2006

Adeno‐associated viruses are small, nonenveloped, single‐stranded viruses of the genus
Dependovirus
, family
Parvoviridae
. They are so named because their propagation depends upon the coinfection by an unrelated virus for essential helper functions.
Dengue Fever Viruses
Authors: Gubler Duane J
Published: September 2006

Dengue viruses are the most important arboviruses causing disease in humans. Over half of the world's population live in areas of risk, and an estimated 50–100 million cases occur each year.
Haemorrhagic Fever Viruses
Authors: Le Guenno Bernard
Published: September 2006

Viral haemorrhagic fever is a clinical definition for several diseases. They are due to viruses that belong to different families and are transmitted in different ways.
Papillomaviruses
Authors: Christensen Neil D
Published: September 2006

Papillomaviruses are small DNA tumour viruses that cause hyperproliferative lesions known as warts. A subset of human papillomaviruses (HPVs) that infect genital tissues are associated with cancers of the uterine cervix (cervical cancer) and other anogenital sites. Viral genes with oncogenic activities have been described, and treatments of HPV‐associated disease including preventive strategies are currently under assessment.
Prion Diseases
Authors: Heppner Frank L , Aguzzi Adriano
Published: September 2006

Prion diseases, or transmissible spongiform encephalopathies, are degenerative disorders of the central nervous system and are of sporadic, familial or acquired nature. They include Creutzfeldt–Jakob disease (CJD), Gerstmann–Sträussler–Scheinker syndrome, kuru and fatal familial insomnia in humans, as well as all prion encephalopathies of animals. The latter comprise scrapie in sheep, bovine spongiform encephalopathy (BSE), or ‘mad cow disease’, and chronic wasting diseases of mule, deer and exotic ungulates. In the last few years, a great body of circumstantial evidence has accumulated indicating that BSE prions can provoke new variant CJD.
Respiratory Syncytial Virus
Authors: Pringle Craig R
Published: September 2006

Respiratory syncytial virus is a ubiquitous 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.
Retroviral Replication
Authors: Pedersen Finn Skou , Duch Mogens
Published: September 2006

Retroviruses are enveloped animal RNA viruses that replicate via a DNA intermediate which is integrated into host cell chromosomal DNA. Expression of viral RNA and proteins from the DNA intermediate utilizes the normal transcription and translation machinery of the host.
Rhinoviruses
Authors: Couch Robert B
Published: September 2006

Rhinoviruses are small, ribonucleic acid‐containing viruses that exhibit a high degree of species specificity and a preference for growth in the nose. They are the most common cause of common colds.
Rubella Virus
Authors: Frey Teryl K , Katow Shigetaka
Published: September 2006

Rubella virus
is an important human pathogen that causes birth defects when infection occurs during early pregnancy. Although the range of birth defects can vary widely, in the most severe cases lifelong care is required. Rubella is controlled by vaccination in most developed countries, but vaccination has not yet been introduced to most developing countries. In the absence of control by vaccination, rubella is the leading teratogenic agent of an infectious nature.
Virus Evolution
Authors: Domingo Esteban
Published: September 2006

Viruses act as independent evolutionary units in continuous interaction with their host organisms. The evolutionary strategies of DNA and RNA viruses differ.
Virus Structure
Authors: McKenna Robert , Faulkner Lee
Published: September 2006

Viruses are infectious obligate intracellular parasites consisting of RNA or DNA in a protective coat. They cannot increase in size but can replicate in susceptible host cells, which may or may not be destroyed by viral replication and release.
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 ICTV and the Virology Division of the IUMS have been in charge of this task since 1966.
Aquificales
Authors: Huber Robert , Stetter Karl O
Published: September 2006

Based on 16S rDNA sequence comparisons, the order Aquificales represents a very deep phylogenetic branch within the bacterial domain. Some Aquificales relatives have an upper temperature border of growth at 95°C. Together with members of the order Thermotogales, they represent the bacteria with the highest growth temperatures known so far.
Archaea: Diversity
Authors: Boone David R , Reysenbach Anna‐Louise
Published: September 2006

The Archaea are a group of microscopic prokaryotes that superficially resemble bacteria but are evolutionarily distinct.
Prokaryotic Systematics: a Theoretical Overview
Authors: Tindall BJ
Published: September 2006

Systematics describes the ordering of information on organisms. It plays an important underlying role in communicating information within the biological sciences.
Bacteroides
Authors: Shah Haroun N , Gharbia Saheer E
Published: September 2006

TheBacteroidesare a genus of small nonmotile, nonsporing, Gram‐negative rods; they are obligate anaerobes and form a major part of the bacterial flora of the human intestinal tract.
Cyanobacteria
Authors: Palinska Katarzyna A , Horgan William J , Krumbein Wolfgang E.
Published: September 2006

The cyanobacteria are a widely distributed group of unicellular and multicellular photosynthetic bacteria that possess chlorophyll
a
(Prochlorales additionally possess chlorophyll
b
) and perform oxygenic photosynthesis.
Gram‐type Positive Bacteria
Authors: Byrer Dorothy E , Wiegel Juergen
Published: September 2006

Gram‐type positive bacteria are characterized by the presence of a thick peptidoglycan layer and the absence of lipopolysaccharide and an outer membrane. Though closely related phylogenetically, these bacteria are diverse in habitats, metabolism, and medical and industrial importance.
Microorganisms
Authors: Hayward Chris A
Published: September 2006

Microorganisms are microscopically small organisms resolved as separate cells under a light microscope. They comprise the prokaryotes (Bacteria and Archaea) and eukaryotes (unicellular plants and animals, and many fungi). They are important in public health, agriculture, and the environment, and are exploited economically in biotechnology.
Semantides and Modern Bacterial Systematics
Authors: Fuerst John A
Published: September 2006

Bacterial systematics can be defined as the scientific study of the kinds and diversity of bacterial microorganisms (i.e. prokaryotes including those in both domains Bacteria and Archaea) and their relationships.
Proteobacteria
Authors: Kersters Karel , Vos Paul De , Gillis Monique , Swings Jean
Published: September 2006

The Proteobacteria constitute one of the major lineages (phyla) within the domain of the
Bacteria
. Although these Gram‐negative bacteria are phylogenetically related, they are physiologically, morphologically and ecologically extremely diverse. They are of great biological importance because they include various pathogens of humans, animals and plants, as well as a number of taxa that play key roles in the carbon, sulfur and nitrogen cycles on our planet.
Bacterial Plasmids
Authors: Summers David
Published: September 2006

Plasmids are carriers of accessory genetic information in bacteria and are capable of infectious spread through bacterial populations. They regulate their own replication and transmission and are largely responsible for the proliferation of antibiotic resistance during the second half of the twentieth century.
Chlorinated Hydrocarbon Metabolism
Authors: Reineke Walter , Kaschabek Stefan R
Published: September 2006

Aerobic bacteria are able to use chlorinated hydrocarbons as the sole source of carbon and energy, leading to carbon dioxide, chloride and biomass; some anaerobic bacteria can use some chlorinated hydrocarbons as an artificial electron acceptor in reductive dechlorination. The ligninolytic enzyme system of white rot fungi exhibits ‘side activities’ for chlorinated aromatic compounds, though without value for the fungi. Liver enzymes are responsible for the formation of hydrophilic intermediates ready for excretion; these detoxifications often lead to highly reactive and potentially toxic intermediates.
Methanogenesis
Authors: Barber Robert D , Ferry James G
Published: September 2006

Biogenic methane production–methanogenesis–is a microbial process carried out by a unique class of prokaryotes. Ultimately, methanogenesis plays an essential role in the global carbon cycle, including new areas such as bioremediation.
Ti Plasmids
Authors: Otten Leon
Published: September 2006

Ti plasmids are plasmids from the genusAgrobacteriumthat encode a natural system of plant transformation. They are used extensively as vectors for plant genetic engineering.
Immune Defence: Microbial Interference
Authors: Merino Susana , Tomás Juan M
Published: September 2006

Extracellular and intracellular pathogens have developed different structural components and enzyme systems to interfere and evade effective humoral and cellular host immune defences.
Phagocytosis
Authors: Russell David G
Published: September 2006

Phagocytosis is the ingestion of particles by cells. The process is usually observed in macrophages and amoebae and almost invariably culminates in the degradation of the ingested particle in the cell's lysosome.
Vaccines: Whole Organism
Authors: Dougan Gordon
Published: September 2006

Vaccines are designed to protect people or animals against the clinical symptoms associated with infection by particular pathogenic agents. They are composed of antigens, derived from pathogens, that can be presented to the immune system in order to induce a protective immune response.
Immunity to Fungi
Authors: Casadevall Arturo
Published: September 2006

The medically important fungi are a diverse group of pathogens that employ a variety of virulence strategies to establish themselves in the host. Successful host defence against fungi requires collaboration between innate and acquired humoral and cellular immune mechanisms.
Antibody‐dependent Cell‐mediated Cytotoxicity (ADCC)
Authors: Graziano Robert F , Guyre Paul M
Published: September 2006

Antibody‐dependent cell‐mediated cytotoxicity (ADCC) is the nonphagocytic killing of an antibody‐coated target cell by a cytotoxic effector cell. ADCC is triggered through interaction of target‐bound antibodies with Fc receptors, molecules on the effector cell surface that recognize the Fc region of immunoglobulins. Effector cells that mediate ADCC include natural killer cells, monocytes, macrophages, neutrophils, eosinophils and dendritic cells.
Antigens: Lipids
Authors: Matsuda Kazuhiro , Yamamoto Naoki , Saito Masaki
Published: September 2006

Phospholipids and glycolipids are major components of biomembranes. Immune responses against them are implicated in several human diseases and in recognition by higher organisms of microbial infections. Structural analysis of lipid antigens is important for understanding the mechanisms of molecular interactions and the pathogenesis of immune abnormalities.
Antigens: Thymus Independent
Authors: Möller Goran
Published: September 2006

Thymus‐independent (TI) antigens are capable of directly activating B lymphocytes into antibody production without helper cells or helper factors. These antigens are mostly of microbial origin, such as lipopolysaccharide from Gram‐negative bacteria, polymerized flagellin, pneumococcal polysaccharide type III, and levans and dextrans from bacteria and they normally induce an early specific immunoglobulin M antibody response, which often exhibit cyclical fluctuations. Apart from their ability to induce an immune response without T helper lymphocytes and their microbial origin, there is little in common between different TI antigens.
Bone Marrow
Authors: Hodgson George S , Dunn Ashley R
Published: September 2006

Bone marrow is the site of production of blood cells: granulocytes, lymphocytes, macrophages, platelets and red cells; it also plays a major role in the control of cell production.
Epitopes
Authors: Muller Claude P
Published: September 2006

Epitopes are three‐dimensional structures on the surface of biological molecules that mediate specific recognition by the immune system. Since in a biological system antibody molecules face a virtually infinite number of structures, cognate interactions with epitopes are the basis of the primordial intelligence that drives the teleological choices of the immune system.
Fertility: Immunological Control
Authors: Aitken R John
Published: September 2006

Fertilization and embryo implantation are considered as potential targets for immunocontraception in terms of their feasibility, desirability and current status.
Fetal–Maternal Immunological Relationships
Authors: Chaouat Gérard
Published: September 2006

Despite inheriting half of its genetic material from its father, the fetus is not rejected by the maternal immune system because of a unique immunological relationship with the mother.
Germinal Centres
Authors: Heinen Ernst
Published: September 2006

Germinal centres are lymphoid structures appearing after an antigenic stimulation inside lymph follicles. During this germinal centre reaction, B cells undergo clonal amplifications but also affinity maturation and class switching of their immunoglobulins. These events, occurring under control of T cells and in the peculiar environments created by the follicular dendritic cells, thus lead B cells to mature into B memory cells or into precursors of plasma cells.
Immune Response: Evolution
Authors: Cooper Edwin L
Published: September 2006

Phagocytosis in unicellular animals represents the most ancient and ubiquitous form of defence against foreign material. Multicellular invertebrates and vertebrates possess phagocytic cells and have evolved more complex functions attributed to immuno‐defence cells that specialized into cellular and humoral immune responses.
Immunology of Fish
Authors: Fletcher Thelma C , Secombes Christopher J
Published: September 2006

The study of the processes and molecules associated with the reactions of fish to foreign substances, including microbes and macromolecules.
Immunology of Invertebrates: Humoral
Authors: Gupta Ayodhya P
Published: September 2006

All major groups of invertebrates possess immunocytes that perform the major cell‐mediated immune functions. During massive or prolonged microbial invasion, the cellular defence may be impaired. Under such circumstances, antimicrobial proteins (humoral factors) secreted by the host immune system provide the second line of defence.
Lymphatic System
Authors: Cahill Ross NP , Kimpton Wayne G , Hay John B
Published: September 2006

The lymphatic system functions as a tissue drainage system which controls blood volume and extracellular fluid volume and prevents tissue oedema. Lymphatic circulation of lymphocytes and effector cells are key regulatory components of the immune system.
Lymphoid System
Authors: Reynolds John D , Heng Daniel , Sztukowski Izabela
Published: September 2006

The lymphoid system plays an integral part in the maintenance of health. It is composed of organs, tissues and lymph vessels, and extends into all areas of the body. Numerous types of cell are found throughout the lymphoid organs and tissues, including lymphocytes, dendritic cells and macrophages.
Thymus
Authors: Hugo Patrice , Boyd Richard
Published: September 2006

The thymus, a bilobate gland located in the upper anterior thorax in higher vertebrates, is the major site of T‐lymphocyte production. This primary lymphoid organ composed of various nonlymphoid elements, referred to as the thymic stroma, governs the maturation of haematopoietic precursors into immune‐competent T‐cells.
t
RNA
Synthesis and Regulation
Authors: Ueda Takuya , Watanabe Kimitsuna
Published: September 2006

Transfer RNA is primarily synthesized by transcription by RNA polymerase and becomes the mature form via several steps: processing, splicing, CCA addition and posttranscriptional modification. The concentration of individual tRNA molecules is controlled in order to maintain cellular functions.
Transfer RNA Recognition by Synthetases
Authors: Giegé Richard , Eriani Gilbert
Published: September 2006

Fidelity of tRNA charging by amino acids ensures correct translation of the genetic code into proteins. Charging is catalysed by aminoacyl‐tRNA synthetases in reactions whose specificity is ensured by positive elements, the identity determinants unique to each tRNA and responsible for its recognition by the cognate synthetase, and negative elements, the antideterminants that prevent false recognitions.
Ribosomal Proteins in Eukaryotes
Authors: Stahl Joachim
Published: September 2006

About 80 different ribosomal proteins are imperative for processing and functioning of eukaryotic ribosomes. Most have remained conserved through evolution but several are specific for eukaryotes; some are able to perform extraribosomal functions.
Eukaryotic Ribosomes: Assembly
Authors: Planta Rudi J , Raué Hendrik A
Published: September 2006

Eukaryotic ribosomes contain one copy each of four different RNA species and about 80 different proteins. These components are assembled into ribosomal subunits in the nucleolus in an ordered manner as the precursor ribosomal RNA is processed into the mature form. This assembly requires numerous accessory factors, many of which are small nucleolar ribonucleoprotein particles (snoRNPs).
Translation Initiation Models in Prokaryotes and Eukaryotes
Authors: Londei Paola
Published: September 2006

Translation is one stage of protein synthesis in which messenger RNA (mRNA) acts as a template for the synthesis of DNA; it consists of three phases: initiation, elongation and termination. Eukaryotic and prokaryotic organisms use different strategies to select the translation initiation sites on mRNAs.
Initiator
t
RNAs
in Prokaryotes and Eukaryotes
Authors: Sperling‐Petersen Hans U , Laursen Brian S , Mortensen Kim K
Published: September 2006

A special type of transfer ribonucleic acid (tRNA) is employed in the initiation step of protein synthesis. The differences between the tRNAs involved in initiation and elongation establish the specificity and recognition of the tRNAs by the factors and enzymes involved in the initiation and elongation steps of protein synthesis.
Protein Synthesis in Eukaryotes: Internal Initiation
Authors: Sonenberg Nahum
Published: September 2006

Internal initiation is an alternative mechanism to the general pathway of translation initiation in eukaryotes and involves the internal binding of ribosomes to a specific sequence in the messenger ribonucleic acid (mRNA) called the internal ribosome entry site (IRES). The mRNA 5′ cap structure and a cap‐binding protein, eukaryotic initiation factor (eIF) 4E, play a key role in the canonical mechanism of translation initiation. However, internal initiation is independent of the cap structure and eIF4E. IRES‐mediated translation initiation has been documented for viral and cellular mRNAs, and functions during mitosis and stress conditions, such as apoptosis and hypoxia.
Protein Synthesis Termination
Authors: Tate Warren P , Poole Elizabeth S , Mannering Sally A
Published: September 2006

Protein synthesis termination is the process by which a completed polypeptide is released from the ribosome after the coding information within a messenger ribonucleic acid (mRNA) has been successfully translated.
Protein Synthesis Inhibitors
Authors: Wilson D N , Stelzl U , Nierhaus Knud H
Published: September 2006

The protein synthetic machinery is a highly complicated apparatus that offers many potential sites for functional interference and thus represents a major target for antibiotics.
Proteins: Postsynthetic Modifications
Authors: Kraft Regine , Wittmann‐Liebold Brigitte
Published: September 2006

Analysis of the entire genome (genomics) provides static information about the genes and proteins of an organism. In contrast, total protein analysis (proteomics) reflects the dynamic situation, providing information about the rate of expression and regulation of individual proteins within the cell. Clues as to the function of proteins in diverse cell processes can only be obtained if their structure and modifications or variations are fully understood.
Clathrin‐coated Vesicles and Receptor‐mediated Endocytosis
Authors: Marsh Mark
Published: September 2006

Receptor‐mediated endocytosis (RME) is the highly efficient uptake of extracellular molecules into cells in membrane‐bound vesicles formed by invagination of the plasma membrane. RME frequently occurs through clathrin‐coated vesicles.
Base Excision Repair, AP Endonucleases and DNA Glycosylases
Authors: Sander Miriam , Wilson Samuel H
Published: September 2006

Base excision repair is an important cellular mechanism that protects the integrity of DNA by repairing damage caused by alkylating agents and reactive oxygen species. The altered DNA base, and in some cases a few nucleotides adjacent to the altered base, is removed by excision, and the DNA is repaired by DNA synthesis and ligation.
Caenorhabditis elegans
as an Experimental Organism
Authors: Chisholm Andrew , Jin Yishi
Published: September 2006

Genetic analysis in the small nematode worm
Caenorhabditis elegans
has elucidated the mechanisms of many basic biological processes.
Porphyrias
Authors: Elder George H
Published: September 2006

The porphyrias are diseases caused by partial deficiencies of the enzymes of haem biosynthesis, most of which are inherited. Clinically, they are characterized by acute episodes of abdominal pain, sometimes with mental disturbances and neuropathy, or by skin disease, caused by photosensitization by porphyrins, or by both of these separately or together.
Polyphosphate: From Bugs to Brains
Authors: Sanders David A , Wanner Barry L
Published: September 2006

PolyP is an ancient and ubiquitous energy‐rich molecule that has been shown to have many cellular roles in biology, yet a new fundamental biological role(s) may still await discovery.
Short
DNA
Sequence Repeats
Authors: Mitas Michael
Published: September 2006

The human genome contains numerous segments of short, reiterated nucleotide sequences that are often located near or within transcriptional units. Despite extensive characterization of these DNA elements over three decades, no sequence‐specific role has been firmly established. However, it has been recognized that expansions of certain trinucleotide repeat sequences are associated with several inherited human disorders.
DNACrosslink Repair
Authors: Siede Wolfram
Published: September 2006

Crosslinking agents are bifunctional or polyfunctional chemicals that generate a covalent linkage between complementary deoxyribonucleic acid strands. Repair of interstrand crosslinks has been studied in prokaryotes and in lower and higher eukaryotes. Repair involves the concerted action of nucleotide excision repair and recombinational processing.
DNA Double‐strand Break Repair in Bacteria
Authors: Kobayashi Ichizo
Published: September 2006

DNA double‐strand breaks, which are frequently caused by biological factors, are lethal events in DNA. There are various enzymatic mechanisms that work, often in competition with each other, in the processing of these breaks, and these may bring about death, restoration (repair) or recombinational changes in the genome.