- Pluriblast
The pluriblast is a Pluripotency pluripotent population of Cell biology cells in the early mammal ian conceptus that is distinct from the trophoblast , and gives rise to the germ layer s of the embryo proper , as well as extraembryonic endoderm and extraembryonic mesoderm . Both the pluriblast and trophoblast arise from the Totipotency totipotent cells of the early conceptus. By definition, the pluriblast does not give rise to trophoblast cells during normal development, although it may retain this potential under experimental conditions. In most eutheria n mammals the pluriblast is termed the inner cell mass , as it forms a mass of cells within the fluid filled blastocyst , bounded by the trophoblast. However in metatherian marsupial mammals, and indeed in a small number of eutherian mammals, the pluriblast forms part of the blastocyst wall and no structure exists that can be described as an inner cell mass. Inner cell mass is thus a morphological term peculiar to the majority of eutherian mammals, whereas pluriblast is a functional term more widely applicable to conserved aspects of mammalian development. References Johnson MH and Selwood L 1996 . Nomenclature of early development in mammals. Reproduction, Fertility and Development. 8 759 764. Category Developmental biology ... more details
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- Archaeocyte
Archaeocytes from Greek language Greek wikt archaios archaios beginning and wikt kytos kytos hollow vessel or amoebocytes are Amoeba amoeboid cells found in Sea sponge sponges . They are Totipotency totipotent and have varied functions depending on the species . Location Archaeocytes are located in the mesohyl , an acellular gelatinous matrix, along with other specialized sponge cells including collencyte s and structural elements called spicule s. They move about within the mesohyl with amoeba like movements performing a number of important functions. Functions Cellular differentiation is an essential function of the archaeocyte. All specialized cells within the sponge have its origins with the archaeocyte. This is especially important in Biological reproduction reproduction as the sex cells of the sponge in sexual reproduction are formed from these amoeboid cells. Similarly in asexual reproduction amoebocytes result in the formation of gemmule s which are cyst like spheres containing more amoebocytes as well as other sponge cells including the phylum specific choanocyte . References cite book author Tschinkel, Hayward, Mahoney and Felgenhauer year 2000 title An introduction to Animal Diversity edition 5th publisher Pearson Custome Publishing location Boston id ISBN 0 536 61552 7 cite book author C. Hickman Jr., L. Roberts, S. Keen, A. Larson and D. Eisenhour year 2007 title Animal Diversity edition 4th publisher McGraw Hill location New York id ISBN 978 0 07 252844 2 Cell biology stub Category Poriferans Category Cell biology Category Animal cells pl Archeocyt sr ... more details
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- Callus (cell biology)
Image Callus1.jpg thumb Callus Nicotiana tabacum In biological research and biotechnology, a callus of cells plural calli is a mass of undifferentiated cells. In plant biology, callus cells are those cells that cover a plant wound. ref http www.liv.ac.uk sd21 tisscult what.htm What is Plant Tissue Culture? ref Design A callus cell culture is usually sustained on gel media, in much the same manner as bacteria are grown. Sufficient media consist of agar and the usual mix of macronutrient s and micronutrient s for the given cell type. For plant cells, enrichment with nitrogen , phosphorus , and potassium is especially important. Water is provided as a constituent part of the gel media. Uses A plant cell callus consists of somatic undifferentiated cells from an adult subject plant. A callus is not necessarily genetically homogeneous because a callus is often made from structural tissue, not individual cells. Nevertheless, callus cells are often considered similar enough for standard scientific analysis to be performed as if on a single subject. For example, an experiment may have half a callus undergo a treatment as the experimental group , while the other half undergoes a similar but non active treatment as the control group . Plant cell calluses may be made to differentiate into the specialized tissues of a whole plant, with the addition of a number of hormones or enzymes. This is an ability known as totipotency . This function is similar to that of stem cells in metazoa . A callus is often the target of a gene gun for specific DNA insertion experiments. Callus tissue is of particular use in micropropagation where it can be used to grow genetically identical copies of plants with desirable characteristics. Callus cultures are extremely important in plant biotechnology. On taking intermediate auxin to cytokinin ratio in the medium can give rise to an unorganized growing and dividing mass of unspecialized parenchyma cells. This group of cells are known as a callus. Call ... more details
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- Cell potency
including RNA regulation may play a role in maintaining totipotency at different stages of development ... more details
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- Reprogramming
selfref This article discusses the epigenetic phenomenon for the writing of computer code, see computer programming Reprogramming refers to erasure and remodeling of epigenetic marks, such as DNA methylation , during mammalian development ref Reik . After fertilization some cells of the newly formed embryo migrate to the germinal ridge and will eventually become the germ cells sperm and oocytes . Due to the phenomenon of Genomic Imprinting genomic imprinting , maternal and paternal genomes are differentially marked and must be properly reprogrammed every time they pass through the germline. Therefore, during the process of gametogenesis the primordial germ cells must have their original biparental DNA methylation patterns erased and re established based on the sex of the transmitting parent. After fertilization the paternal and maternal genomes are once again demethylated and remethylated except for differentially methylated regions associated with imprinted genes . This reprogramming is likely required for totipotency of the newly formed embryo and erasure of acquired epigenetic changes. In vitro manipulation of pre implantation embryos has been shown to disrupt methylation patterns at imprinted loci ref Mann and plays a crucial role in cloned animals ref Wrenzycki . Somatic cell nuclear transfer An oocyte can reprogram an adult nucleus into an embryonic state after somatic cell nuclear transfer , so that a new organism can be developed from such cell ref Hochedlinger see also cloning Reprogramming is distinct from development of a somatic epitype ref Lahiri , as somatic epitypes can potentially be altered after an organism has left the developmental stage of life. ref Mathers biology stub References note Reik cite journal author Reik W, Dean W, Walter J title Epigenetic reprogramming in mammalian development journal Science volume 293 issue 5532 pages 1089 93 year 2001 month August pmid 11498579 doi 10.1126 science.1063443 url http www.sciencemag.org cgi pmidlooku ... more details
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- Keith Campbell (biologist)
, I. 1997 . Totipotency or Multipotentiality of Cultured Cells Applications and Progress. Therio ... more details
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- Induced pluripotent stem cell
Dedifferentiation to totipotency or pluripotency an overview of methods. Various methods exist to revert adult somatic cells to pluripotency or totipotency. In the case of totipotency, reprogramming ... to totipotency in a process called chromosome transfer Egli and Eggan, 2010 . Direct reprogramming ... in reprogramming. No cocktail has been identified to completely reprogram adult cells to totipotency ... more details
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- Gene gun
. This capability of total re generation is called totipotency . The new plant that originated from ... more details
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- Joan E. Strassmann
, 12 1031 1038. Strassmann, J. E., Sullender, B. W., and Queller D. C. 2002. Caste totipotency and conflict ... more details
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- Human embryogenesis
embryo. This cell potency totipotency means that some cells can be removed from the preimplantation ... more details
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- Physiological and molecular wheat breeding
. Molecular genetics and bio revolution Totipotency shown by plants gave rise to tissue culture techniques ... more details
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- Plant evolution
Plant evolution is the subset of evolution ary phenomena that concern plants . Evolutionary phenomena are characteristics of Population biology populations that are described by average s, median s, Frequency distribution distributions , and other Statistics statistical methods. This distinguishes plant evolution from Plant morphology Plant development plant development , a branch of developmental biology which concerns the changes that individuals go through in their lives. The study of plant evolution attempts to explain how the present Biodiversity diversity of plants arose over Geologic time scale geologic time . It includes the study of Mutation genetic change and the consequent Natural selection variation that often results in speciation , one of the most important types of Evolutionary radiation radiation into Taxonomy taxonomic groups called clade s. A description of radiation is called a Phylogenetics phylogeny and is often represented by type of diagram called a phylogenetic tree . Evolutionary trends Differences between plant and animal physiology and reproduction cause minor differences in how they evolve. One major difference is the totipotency totipotent nature of plant cells, allowing them to reproduce asexually much more easily than most animals. They are also capable of polyploidy where more than two chromosome sets are inherited from the parents. This allows relatively fast bursts of evolution to occur, for example by the effect of gene duplication Gene duplication as an evolutionary event gene duplication . The long periods of dormancy that seed plants can employ also makes them less vulnerable to extinction, as they can sit out the tough periods and wait until more clement times to leap back to life. The effect of these differences is most profoundly seen during extinction events. These events, which wiped out between 6 and 62 of terrestrial animal families, had negligible effect on plant families. ref name McElwain2007 cite journal author McElwa ... more details
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- Plant tissue culture
Plant tissue culture is a practice used to propagate plant s under sterile conditions, often to produce cloning clones of a plant. Different techniques in plant tissue culture may offer certain advantages over traditional methods of propagation, including The production of exact copies of plants that produce particularly good flowers, fruits, or have other desirable traits. To quickly produce mature plants. The production of multiples of plants in the absence of seed s or necessary pollination pollinators to produce seed s. The regeneration of whole plants from plant cells that have been genetic engineering genetically modified . The production of plants in sterile containers that allows them to be moved with greatly reduced chances of transmitting diseases, pests, and pathogens. The production of plants from seeds that otherwise have very low chances of germinating and growing, i.e. orchids and nepenthes . To clean particular plant of viral and other infections and to quickly multiply these plants as cleaned stock for horticulture and agriculture. Plant tissue culture relies on the fact that many plant cells have the ability to regenerate a whole plant totipotency . Single cells, plant cells without cell walls protoplast s , pieces of leaves, or less commonly roots can often be used to generate a new plant on culture media given the required nutrients and plant hormones . Techniques Modern plant tissue culture is performed under Aseptic technique aseptic conditions under filtered air. Living plant materials from the environment are naturally contaminated on their surfaces and sometimes interiors with microorganisms, so surface Sterile technique sterilization of starting materials explant s in chemical solutions usually alcohol or bleach is required. Mercuric chloride is seldom used as a plant sterilant today, as it is dangerous to use, and is difficult to dispose of. Explants are then usually placed on the surface of a solid culture medium, but are sometimes placed ... more details
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- Myelomalacia
they are Totipotency Totipotent . Adult stem cells are generally limited to differentiating into different ... more details
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- Dolly (sheep)
are still capable of reverting back to an embryonic Totipotency totipotent state, creating a cell ... more details
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- Living systems theory
Totipotency totipotential communities to nation states and non supranational systems have greater ... more details
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- Sperm
pp semi vandalism small yes File Complete diagram of a human spermatozoa en.svg thumb right 350px Diagram of a human sperm cell. Other uses The term sperm is derived from the Greek word sperma meaning seed and refers to the male reproductive Cell biology cells . In the types of sexual reproduction known as anisogamy and oogamy , there is a marked difference in the size of the gamete s with the smaller one being termed the male or sperm cell. The human sperm cell is haploid , so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. A uniflagellar sperm cell that is Motility motile is referred to as a spermatozoon , whereas a non motile sperm cell is referred to as a spermatium . Sperm cells cannot divide and have a limited life span, but after fusion with Ovum egg cells during fertilization, a new organism begins developing, starting as a Totipotency totipotent zygote . cn date January 2011 The spermatozoa of animal s are produced through spermatogenesis inside the male gonad s testicle s via meiosis meiotic division. They are carried out of the male body in a fluid known as semen . Mammalian sperm cells can survive within the female reproductive tract for more than 5 days post coitus ref Gould JE, Overstreet JW and Hanson FW 1984 Assessment of human sperm function after recovery from the female reproductive tract. Biol Reprod 31,888 894. ref . Sperm cells in algal and many plant gametophyte s are produced in male Gametangium gametangia Antheridium antheridia via mitosis mitotic division. In flowering plant s, sperm nuclei are produced inside pollen . cn date January 2011 Anatomy File Sperm egg.jpg thumb right 200px Sperm fertilizing an egg The sperm cell consists of a head, a midpiece and a tail. The head contains the Cell nucleus nucleus with densely coiled chromatin fibres, surrounded anteriorly by an acrosome , which contains enzymes used for penetrating the female egg. The midpiece has a central filamentous core wit ... more details
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- Inner cell mass
W, Tarkowski AK. 2008. Blastomeres of the mouse embryo lose totipotency after the fifth cleavage division ... more details
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- Transgenerational epigenetics
2010 Epigenetic reprogramming of mouse germ cells toward totipotency. Cold Spring Harbor Symposia ... of totipotency in stem cells or cells more generally, thus generalizing regenerative medicine ... more details
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- Stem cell
stem cells to be either totipotency totipotent or pluripotency pluripotent to be able to give rise ... ref Totipotency Totipotent a.k.a omnipotent stem cells can differentiate into embryonic and extraembryonic ... divisions of the fertilized egg are also totipotent. ref cite journal title Totipotency, pluripotency ... more details
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- Index of genetic engineering articles
Thymine dimer Ti plasmid Topoisomer Topoisomerase Totipotency Totipotent Toxicogenomics Trait biological ... more details
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- Tissue engineering
pluripotency pluripotent some cells are totipotency totipotent , in the earliest stages of the embryo ... more details
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- Index of genetics articles
Totipotency Totipotent Toxicogenomics Trait biological Trans isomer Trans Trans conformation Trans acting ... more details
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- Gene
, and human diseases. Gene targeting is also in theory applicable to species from which Totipotency ... more details
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- Epigenetics
totipotency and multipotency . In mammal s, some stem cells continue producing new differentiated ... more details
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