GetSharedSiteSession?rc=1&redirect= Identification of cVA Opsin Additional bioinformatic analyses of other genome databases allowed us to identify VA-like genes in multiple vertebrate classes, including the Amphibia (Xenopus laevis), the Reptilia (Anolis carolinensis), and the Elasmobranchii (Callorhinchus milii), but failed to find any VA homologs within the mammalian databases.
International Journal of Biological Sciences 02: 0038 image No. 02. Gap junction - Wikipedia. A gap junction may also be called a nexus or macula communicans.
When found in neurons or nerves it may also be called an electrical synapse. While an ephapse has some similarities to a gap junction, by modern definition the two are different. One gap junction channel is composed of two connexons (or hemichannels), which connect across the intercellular space. Gap junctions are analogous to the plasmodesmata that join plant cells. Gap junctions occur in virtually all tissues of the body, with the exception of adult fully developed skeletal muscle and mobile cell types such as sperm or erythrocytes. Category Results. LARVAE OF PORIFERA-COELENTERATA-PLATY HELMENTHES. Parenchymula (Stereo- gastrula) --- Leucosolenia -- Rhagon ----Higher sponges 3.Amphiblastula---Sycon 1.
Planula -- Obelia, Sea Anemone 3. Epiblast - Embryonic Development & Stem Cells - LifeMap Discovery. Embryonic Development of the Epiblast: The epiblast is formed as the inner cell mass (ICM) segregates into a bilaminar embryonic disc (bilaminar blastoderm) which consists of two epithelial layers, each of a distinct lineage: the external (dorsal) epiblast and the internal (ventral) hypoblast.
Embryonic Derivatives of the Epiblast: Gastrulation is the process in which the ICM in converted into the trilaminar embryonic disc, which is comprised of the three germ layers (ectoderm, mesoderm and endoderm). Formation of the primitive streak marks the first event of gastrulation. Dopamine. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells.
The brain includes several distinct dopamine pathways, one of which plays a major role in reward-motivated behavior. Most types of rewards increase the level of dopamine in the brain, and many addictive drugs increase dopamine neuronal activity. Other brain dopamine pathways are involved in motor control and in controlling the release of various hormones. These pathways and cell groups form a dopamine system which is neuromodulatory. Outside the central nervous system, dopamine functions primarily as a local chemical messenger.
Melanin - Wikipedia. Melanin pigment (light refracting granular material—center of image) in a pigmented melanoma.
Melanin i/ˈmɛlənɪn/ (Greek: μέλας – melas, "black, dark") is a broad term for a group of natural pigments found in most organisms. Melanin is produced by the oxidation of the amino acid tyrosine, followed by polymerization. Melatonin. Melatonin, also known as N-acetyl-5-methoxy tryptamine, is a hormone that is produced by the pineal gland in animals and regulates sleep and wakefulness. Melatonin is also produced in plants where it functions as a first line of defense against oxidative stress. As a medicine, it is used for the treatment of insomnia; however, scientific evidence is insufficient to demonstrate a benefit in this area. Melatonin is sold over the counter in the United States and Canada.
In other countries, it may require a prescription or it may be unavailable. Medical uses Enterochromaffin cell - Wikipedia. Enterochromaffin (EC) cells (also known as Kulchitsky cells), discovered by Nikolai Kulchitsky of Karazin Kharkiv National University. They are a type of enteroendocrine and neuroendocrine cell.
They reside alongside the epithelium lining the lumen of the digestive tract and play a crucial role in gastrointestinal regulation, particularly intestinal motility and secretion. EC cells modulate neuron signalling in the enteric nervous system (ENS) via the secretion of the neurotransmitter serotonin and other peptides. As enteric afferent and efferent nerves do not protrude into the intestinal lumen, EC cells act as a form of sensory transduction. Serotonin in the ENS acts in synergy with other digestive hormones to regulate sensory and motor gastrointestinal reflexes. EC cells respond to both chemical and neurological stimuli. They are also reactive to mechanosensation and can be stimulated by a bolus moving through the bowel. Serotonin - Wikipedia. Serotonin (/ˌsɛrəˈtoʊnᵻn, ˌsɪərə-/) or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter.
Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract (GI tract), blood platelets, and the central nervous system (CNS) of animals, including humans. Tunicate ampullae. TUNICATE CHIMERAS. Do chimeric colonial tunicates form under natural conditions in the sea?
A survey of 309 colonies of Botryllus schlosseri in Monterey Marina, California indicates that about 20% are in allogenic1 contact with conspecifics and thus have the potential to fuse into chimeras (no data are provided for actual frequency of fusion). Interestingly, a comparison2 of chimeras with “normal” colonies shows that in several life-history traits the chimeras have reduced fitness. Thus, in terms of growth3, age/size at first reproduction,and especially fecundity, chimeras do more poorly than colonies in isolation or colonies in allogeneic contact that have failed to fuse with their neighbours. The authors note that this is the first documentation in a tunicate that allogenic contact4 leading to both fusion and rejection come at a cost to life-history processes of growth and reproduction. The authors also briefly discuss the pros and cons of fusion for a colonial tunicate. NOTE1 lit. L-DOPA - Wikipedia. Medical use In addition, L-DOPA, co-administered with a peripheral DDCI, has been investigated as a potential treatment for restless leg syndrome.
However, studies have demonstrated "no clear picture of reduced symptoms". The two types of response seen with administration of L-DOPA are: The short-duration response is related to the half-life of the drug.The longer-duration response depends on the accumulation of effects over at least two weeks, during which ΔFosB accumulates in nigrostriatal neurons. In the treatment of Parkinson's disease, this response is evident only in early therapy, as the inability of the brain to store dopamine is not yet a concern. Neuromelanin - Wikipedia. 5,6-dihydroxyindole, the monomer out of which neuromelanin polymers are formed. Neuromelanin (NM) is a dark pigment found in the brain which is structurally related to melanin. It is a polymer of 5,6-dihydroxyindole monomers. L-DOPA - Wikipedia. Phylogenetic and symbiogenetic tree of living organisms, showing the origins of eukaryotes & prokaryotes One hypothesis of eukaryotic relationships, modified from Simpson and Roger (2004).
In 2004, a review article by Simpson and Roger noted that the Protista were "a grab-bag for all eukaryotes that are not animals, plants or fungi". They held that only monophyletic groups should be accepted as formal ranks in a classification and that - while this approach had been impractical previously (necessitating "literally dozens of eukaryotic 'kingdoms'") - it had now become possible to divide the eukaryotes into "just a few major groups that are probably all monophyletic". Carl Linnaeus (1707–1778) laid the foundations for modern biological nomenclature, now regulated by the Nomenclature Codes, in 1735. He distinguished two kingdoms of living things: Regnum Animale ('animal kingdom') and Regnum Vegetabile ('vegetable kingdom', for plants). In the Whittaker system, Plantae included some algae. Five Kingdom Classification System. Once upon a time, all living things were lumped together into two kingdoms, namely plants and animals (at least, that's how I learned it).
Animals included every living thing that moved, ate, and grew to a certain size and stopped growing. Plants included every living thing that did not move or eat and that continued to grow throughout life. Chapter 12A. Plant Development. Double fertilization. One sperm nucleus fertilizes the egg, generating a 2N diploid zygote. Another sperm nucleus fertilizes a polar cell with two 1N nuclei, generating a 3N triploid endosperm, which provides nutrients to the developing embryo. from The Online Biology Book Embryogenesis. The Structure and Functions of Flowers. The Structure and Functions of Flowers The Female Reproductive Organ: The Carpel The female parts of a flower consist of an ovary, which contains one or more ovules, a style and the stigma.
Developmental Biology 3230. Cleavage refers to the stereotyped pattern of early mitotic divisions that divides up the large volume egg cytoplasm. Introductionto bilateria 2012. GEOL 331 Principles of Paleontology. Eumetazoa: (Ediacaran - Quaternary) Includes Cnidaria, Ctenophora, and Bilateralia. The Latin name of the phylum derives from the numerous pores found on the body surface.
The 9,000 or so species are all aquatic with most representatives living in salt water, although about 100 species live in fresh water habitats. Developmental Biology in the Ocean 2013: Nematostella vectensis. Nematostella - Wikipedia. Bilateria. Except for a few phyla (i.e. flatworms and gnathostomulids), bilaterians have complete digestive tracts with a separate mouth and anus.
Some bilaterians lack body cavities (acoelomates, i.e. Nematostella. Volvox - Wikipedia. Description Volvox colony: 1) Chlamydomonas-like cell, 2) Daughter colony, 3) Cytoplasmic bridges, 4) Intercellular gel, 5) Reproductive cell, 6) Somatic cell. Reproduction An asexual colony includes both somatic (vegetative) cells, which do not reproduce, and large, non-motile gonidia in the interior, which produce new colonies through repeated division. In sexual reproduction two types of gametes are produced. Volvox species can be monoecious or dioecious. Volvox is facultatively sexual and can reproduce both sexually and asexually. Volvox - Volvox - Wikipedia. Description WVGES Mini-Museum, What's New? The Artful Amoeba - Scientific American Blog Network. Theory of evolution. Learn Science at Scitable. GlycoWord / Evolution-ES-A02. Choanoflagellates. PubMed Central, Fig. 2: Cell Mol Life Sci. 2011 Oct; 68(19): 3201–3207. Published online 2011 Aug 11. doi: 10.1007/s00018-011-0784-5.
WoRMS - World Register of Marine Species - Synoicum adareanum (Herdman, 1902) Fossil Octopuses. Squid Evolution - Squid Facts and Information. iBiology: Bringing the world's best biology videos to you. Science Education - National Institute of General Medical Sciences. Neoteny. Atlas of Human Embryos [by: RF Gasser, PhD.] - Ch.5. What can we learn about our limbs from the limbless? Lines of Evidence: Developmental Biology, Page 1 of 2.
Unicellular Organisms – The Cambrian Explosion – Nano Machines. Chlorocruorin. Red Blood Cells. Neanderthal and Denisovan Genomes. Aragonite sea. Supercontinent cycle. Pangaea. October 12, 2009, 364 (1531)