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Cell Fate Determination
Within the field of developmental biology, one goal is to understand how a particular cell develops into a specific cell type, known as fate determination. In an embryo, several processes play out at a molecular level to create an organism. These processes include cell proliferation, differentiation, cellular movement and programmed cell death. Each cell in an embryo receives molecular signals from neighboring cells in the form of proteins, RNAs and even surface interactions. Almost all animals undergo a similar sequence of events during very early development, a conserved process known as embryogenesis. During embryogenesis, cells exist in three germ layers, and undergo gastrulation. While embryogenesis has been studied for more than a century, it was only recently (the past 25 years or so) that scientists discovered that a basic set of the same proteins and mRNAs are involved in embryogenesis. Evolutionary conservation is one of the reasons that model organisms such as the fruit f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developmental Biology
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism. Perspectives The main processes involved in the embryogenesis, embryonic development of animals are: tissue patterning (via regional specification and patterned cellular differentiation, cell differentiation); tissue growth; and tissue morphogenesis. * Regional specification refers to the processes that create the spatial patterns in a ball or sheet of initially similar cells. This generally involves the action of cytoplasmic determinants, located within parts of the fertilized egg, and of inductive signals emitted from signaling centers in the embryo. The early stages of regional specification do not generate functional differentiated cells, but cell populations committed to developing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caenorhabditis Elegans
''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a Hybrid word, blend of the Greek ''caeno-'' (recent), ''rhabditis'' (rod-like) and Latin ''elegans'' (elegant). In 1900, Émile Maupas, Maupas initially named it ''Rhabditidae, Rhabditides elegans.'' Günther Osche, Osche placed it in the subgenus ''Caenorhabditis'' in 1952, and in 1955, Ellsworth Dougherty, Dougherty raised ''Caenorhabditis'' to the status of genus. ''C. elegans'' is an unsegmented pseudocoelomate and lacks respiratory or circulatory systems. Most of these nematodes are hermaphrodites and a few are males. Males have specialised tails for mating that include spicule (nematode), spicules. In 1963, Sydney Brenner proposed research into ''C. elegans,'' primarily in the area of neuronal development. In 1974, he began research into the molecular biology, molecular and developmental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Ablation
Cell ablation (from Latin ''Cellula'' "small chamber" and ''Ablatio'' "removal"). Also known as tissue ablation, cell ablation is a biotechnological tool for studying cell lineage. The process consists of selectively destroying or removing cells in an organism. For example, a laser beam or controllable gene promoter for a toxin gene can be used to destroy a selected amount of cells. Cell ablation can also be used as a tool to produce transgenic organisms lacking a cell type, and as a cure for certain diseases such as cancer. The term is not to be confused with genetic ablation: a method of modifying DNA in order to disrupt the production of a specific gene. There are multiple different techniques of cell ablation (laser ablation, thermal ablation, etc...). Many of which are being utilized in biomedical sciences to study cell functions Laser cell ablation Laser was used during the early stages of cell ablation, utilizing the flexibility, precision and heat generated from concen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetry Breaking
In physics, symmetry breaking is a phenomenon where a disordered but Symmetry in quantum mechanics, symmetric state collapses into an ordered, but less symmetric state. This collapse is often one of many possible Bifurcation theory, bifurcations that a particle can take as it approaches a lower energy state. Due to the many possibilities, an observer may assume the result of the collapse to be arbitrary. This phenomenon is fundamental to quantum field theory (QFT), and further, contemporary understandings of physics. Specifically, it plays a central role in the Glashow–Weinberg–Salam model which forms part of the Standard model modelling the electroweak sector.In an infinite system (Minkowski space, Minkowski spacetime) symmetry breaking occurs, however in a finite system (that is, any real super-condensed system), the system is less predictable, but in many cases Quantum tunnelling, quantum tunneling occurs. Symmetry breaking and tunneling relate through the collapse of a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notch Signaling
The Notch signaling pathway is a highly conserved cell signaling system present in most animals. Mammals possess four different notch receptors, referred to as NOTCH1, NOTCH2, NOTCH3, and NOTCH4. The notch receptor is a single-pass transmembrane receptor protein. It is a hetero-oligomer composed of a large extracellular portion, which associates in a calcium-dependent, non-covalent interaction with a smaller piece of the notch protein composed of a short extracellular region, a single transmembrane-pass, and a small intracellular region. Notch signaling promotes proliferative signaling during neurogenesis, and its activity is inhibited by Numb to promote neural differentiation. It plays a major role in the regulation of embryonic development. Notch signaling is dysregulated in many cancers, and faulty notch signaling is implicated in many diseases, including T-cell acute lymphoblastic leukemia ( T-ALL), cerebral autosomal-dominant arteriopathy with sub-cortical infarcts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Inhibition
In neurobiology, lateral inhibition is the capacity of an excited neuron to reduce the activity of its neighbors. Lateral inhibition disables the spreading of action potentials An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific cell rapidly rises and falls. ... from excited neurons to neighboring neurons in the lateral direction. This creates a contrast in stimulation that allows increased sensory perception. It is also referred to as lateral antagonism and occurs primarily in visual processes, but also in Touch, tactile, Auditory system, auditory, and even olfactory processing. Cells that utilize lateral inhibition appear primarily in the cerebral cortex and thalamus and make up lateral inhibitory networks (LINs). Artificial lateral inhibition has been incorporated into artificial sensory systems, such as vision c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleavage (embryo)
In embryology, cleavage is the division of cells in the early development of the embryo, following fertilization. The zygotes of many species undergo rapid cell cycles with no significant overall growth, producing a cluster of cells the same size as the original zygote. The different cells derived from cleavage are called blastomeres and form a compact mass called the morula. Cleavage ends with the formation of the blastula, or of the blastocyst in mammals. Depending mostly on the concentration of yolk in the egg, the cleavage can be holoblastic (total or complete cleavage) or meroblastic (partial or incomplete cleavage). The pole of the egg with the highest concentration of yolk is referred to as the vegetal pole while the opposite is referred to as the animal pole. Cleavage differs from other forms of cell division in that it increases the number of cells and nuclear mass without increasing the cytoplasmic mass. This means that with each successive subdivision, there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalence Group
An equivalence group is a set of unspecified cells that have the same developmental potential or ability to adopt various fates. Our current understanding suggests that equivalence groups are limited to cells of the same ancestry, also known as sibling cells. Often, cells of an equivalence group adopt different fates from one another. Equivalence groups assume various potential fates in two general, non-mutually exclusive ways. One mechanism, induction, occurs when a signal originating from outside of the equivalence group specifies a subset of the naïve cells. Another mode, known as lateral inhibition, arises when a signal within an equivalence group causes one cell to adopt a dominant fate while others in the group are inhibited from doing so. In many examples of equivalence groups, both induction and lateral inhibition are used to define patterns of distinct cell types. Cells of an equivalence group that do not receive a signal adopt a default fate. Alternatively, cells tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brainbow
Brainbow is a process by which individual neurons in the brain can be distinguished from neighboring neurons using fluorescent proteins. By randomly expressing different ratios of red, green, and blue derivatives of green fluorescent protein in individual neurons, it is possible to flag each neuron with a distinctive color. This process has been a major contribution to the field of neural connectomics. The technique was originally developed in 2007 by a team led by Jeff W. Lichtman and Joshua R. Sanes, both at Harvard University. The original technique has been adapted for use with other model research organisms including the fruit fly (''Drosophila melanogaster''), zebrafish (''Danio rerio''), and ''Arabidopsis thaliana''. While earlier labeling techniques allowed for the mapping of only a few neurons, this new method allows more than 100 differently mapped neurons to be simultaneously and differentially illuminated in this manner. This leads to its characteristic multicolored ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cre-Lox Recombination
Cre-Lox recombination is a site-specific recombinase technology, used to carry out deletions, insertions, translocations and inversions at specific sites in the DNA of cells. It allows the DNA modification to be targeted to a specific cell type or be triggered by a specific external stimulus. It is implemented both in eukaryotic and prokaryotic systems. The Cre-lox recombination system has been particularly useful to help neuroscientists to study the brain in which complex cell types and neural circuits come together to generate cognition and behaviors. NIH Blueprint for Neuroscience Research has created several hundreds of Cre driver mouse lines which are currently used by the worldwide neuroscience community. An important application of the Cre-lox system is excision of selectable markers in gene replacement. Commonly used gene replacement strategies introduce selectable markers into the genome to facilitate selection of genetic mutations that may cause growth retardation. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super-resolution Microscopy
Super-resolution microscopy is a series of techniques in optical microscopy that allow such images to have Optical resolution, resolutions higher than those imposed by the Diffraction-limited system, diffraction limit, which is due to the diffraction of light. Super-resolution imaging techniques rely on the Electromagnetic radiation#Near and far fields, near-field (photon-tunneling microscopy as well as those that use the Superlens, Pendry Superlens and near field scanning optical microscopy) or on the Near and far field, far-field. Among techniques that rely on the latter are those that improve the resolution only modestly (up to about a factor of two) beyond the diffraction-limit, such as confocal microscopy with closed pinhole or aided by computational methods such as deconvolution or detector-based pixel reassignment (e.g. re-scan microscopy, pixel reassignment), the 4Pi Microscope, 4Pi microscope, and structured-illumination microscopy technologies such as SIM and Vertico SMI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confocal Microscopy
Confocal microscopy, most frequently confocal laser scanning microscopy (CLSM) or laser scanning confocal microscopy (LSCM), is an optical imaging technique for increasing optical resolution and contrast (vision), contrast of a micrograph by means of using a Spatial filter, spatial pinhole to block out-of-focus light in image formation. Capturing multiple two-dimensional images at different depths in a sample enables the reconstruction of three-dimensional structures (a process known as optical sectioning) within an object. This technique is used extensively in the scientific and industrial communities and typical applications are in life sciences, semiconductor inspection and materials science. Light travels through the sample under a conventional microscope as far into the specimen as it can penetrate, while a confocal microscope only focuses a smaller beam of light at one narrow depth level at a time. The CLSM achieves a controlled and highly limited depth of field. Basic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
