|
Protochlorophyllide
Protochlorophyllide,KEGG compound database entr/ref> or monovinyl protochlorophyllide, is an intermediate in the biosynthesis of chlorophyll ''a''. It lacks the phytol side-chain of chlorophyll and the reduced pyrrole in ring D. Protochlorophyllide is highly fluorescent; mutants that accumulate it glow red if irradiated with blue light.Meskauskiene R, Nater M, Goslings D, Kessler F, op den Camp R, Apel K. FLU: a negative regulator of chlorophyll biosynthesis in Arabidopsis thaliana. Proceedings of the National Academy of Sciences of the United States of America. 2001; 98(22):12826-3pdf In angiosperms, the later steps which convert protochlorophyllide to chlorophyll are light-dependent, and such plants are pale (chlorotic) if grown in the darkness. Gymnosperms, algae, and photosynthetic bacteria have another, light-independent enzyme and grow green in the darkness as well. Conversion to chlorophyll The enzyme that converts protochlorophyllide to chlorophyllide ''a'', the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to absorb energy from light. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. The presence of magnesium in chlorophyll was discovered in 1906, and was that element's first detection in living tissue. After initial work done by German chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminolevulinic Acid
δ-Aminolevulinic acid (also dALA, δ-ALA, 5ALA or 5-aminolevulinic acid), an endogenous non-proteinogenic amino acid, is the first compound in the porphyrin synthesis pathway, the pathway that leads to heme in mammals, as well as chlorophyll in plants. 5ALA is used in photodynamic detection and surgery of cancer.Wagnières, G.., Jichlinski, P., Lange, N., Kucera, P., Van den Bergh, H. (2014). Detection of Bladder Cancer by Fluorescence Cystoscopy: From Bench to Bedside - the Hexvix Story. Handbook of Photomedicine, 411-426. Medical uses As a precursor of a photosensitizer, 5ALA is also used as an add-on agent for photodynamic therapy. In contrast to larger photosensitizer molecules, it is predicted by computer simulations to be able to penetrate tumor cell membranes. Cancer diagnosis Photodynamic detection is the use of photosensitive drugs with a light source of the right wavelength for the detection of cancer, using fluorescence of the drug. 5ALA, or derivatives thereof, can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyllide
Chlorophyllide ''a'' and Chlorophyllide ''b'' are the biosynthetic precursors of chlorophyll ''a'' and chlorophyll ''b'' respectively. Their propionic acid groups are converted to phytyl esters by the enzyme chlorophyll synthase in the final step of the pathway. Thus the main interest in these chemical compounds has been in the study of chlorophyll biosynthesis in plants, algae and cyanobacteria. Chlorophyllide ''a'' is also an intermediate in the biosynthesis of bacteriochlorophylls. Structures Chlorophyllide ''a'', is a carboxylic acid (R=H). In chlorophyllide ''b'', the methyl group at position 13 ( IUPAC numbering for chlorophyllide ''a'') and highlighted in the green box, is replaced with a formyl group. Biosynthesis steps up to formation of protoporphyrin IX In the early steps of the biosynthesis, which starts from glutamic acid, a tetrapyrrole is created by the enzymes deaminase and cosynthetase which transform aminolevulinic acid via porphobilinogen and hydroxymethy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protochlorophyllide Reductase
In enzymology, protochlorophyllide reductases (POR) are enzymes that catalyze the conversion from protochlorophyllide to chlorophyllide ''a''. They are oxidoreductases participating in the biosynthetic pathway to chlorophylls. There are two structurally unrelated proteins with this sort of activity, referred to as light-dependent (LPOR) and dark-operative (DPOR). The light- and NADPH-dependent reductase is part of the short-chain dehydrogenase/reductase (SDR) superfamily and is found in plants and oxygenic photosynthetic bacteria, while the ATP-dependent dark-operative version is a completely different protein, consisting of three subunits that exhibit significant sequence and quaternary structure similarity to the three subunits of nitrogenase.Yuichi Fujita and Carl E. Bauer (2000). Reconstitution of Light-independent Protochlorophyllide Reductase from Purified Bchl and BchN-BchB Subunits. J. Biol. Chem., Vol. 275, Issue 31, 23583-23588/ref> This enzyme may be evolutionary ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loblolly Pine
''Pinus taeda'', commonly known as loblolly pine, is one of several pines native to the Southeastern United States, from East Texas to Florida, and north to southern New Jersey. The wood industry classifies the species as a southern yellow pine. U.S. Forest Service surveys found that loblolly pine is the second-most common species of tree in the United States, after red maple. For its timber, the pine species is regarded as the most commercially important tree in the Southeastern U.S. The common name loblolly is given because the pine species is found mostly in lowlands and swampy areas. Loblolly pine is the first among over 100 species of ''Pinus'' to have its complete genome sequenced. As of March 2014, it was the organism having the largest sequenced genome size. Its genome, with 22 billion base pairs, is seven times larger than that of humans. As of 2018, assembly of the axolotl genome (32Gb) displaced loblolly pine as the largest assembled genome. The loblolly pine was sel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Splicing
RNA splicing is a process in molecular biology where a newly-made precursor messenger RNA (pre-mRNA) transcript is transformed into a mature messenger RNA (mRNA). It works by removing all the introns (non-coding regions of RNA) and ''splicing'' back together exons (coding regions). For nuclear-encoded genes, splicing occurs in the nucleus either during or immediately after transcription. For those eukaryotic genes that contain introns, splicing is usually needed to create an mRNA molecule that can be translated into protein. For many eukaryotic introns, splicing occurs in a series of reactions which are catalyzed by the spliceosome, a complex of small nuclear ribonucleoproteins (snRNPs). There exist self-splicing introns, that is, ribozymes that can catalyze their own excision from their parent RNA molecule. The process of transcription, splicing and translation is called gene expression, the central dogma of molecular biology. Splicing pathways Several methods of RNA splici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydomonas
''Chlamydomonas'' is a genus of green algae consisting of about 150 speciesSmith, G.M. 1955 ''Cryptogamic Botany Volume 1. Algae and Fungi'' McGraw-Hill Book Company Inc of unicellular flagellates, found in stagnant water and on damp soil, in freshwater, seawater, and even in snow as "snow algae". ''Chlamydomonas'' is used as a model organism for molecular biology, especially studies of flagellar motility and chloroplast dynamics, biogenesis, and genetics. One of the many striking features of ''Chlamydomonas'' is that it contains ion channels (channelrhodopsins) that are directly activated by light. Some regulatory systems of ''Chlamydomonas'' are more complex than their homologs in Gymnosperms, with evolutionarily related regulatory proteins being larger and containing additional domains. Molecular phylogeny studies indicated that the traditional genus ''Chlamydomonas'' as defined using morphological data was polyphyletic within Volvocales. Many species were subsequently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Family
A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. One such family are the genes for human hemoglobin subunits; the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci. These two gene clusters are thought to have arisen as a result of a precursor gene being duplicated approximately 500 million years ago. Genes are categorized into families based on shared nucleotide or protein sequences. Phylogenetic techniques can be used as a more rigorous test. The positions of exons within the coding sequence can be used to infer common ancestry. Knowing the sequence of the protein encoded by a gene can allow researchers to apply methods that find similarities among protein sequences that provide more information than similarities or differences among DNA sequences. If the genes of a gene family encode proteins, the term '' protein family'' is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thylakoid
Thylakoids are membrane-bound compartments inside chloroplasts and cyanobacteria. They are the site of the light-dependent reactions of photosynthesis. Thylakoids consist of a thylakoid membrane surrounding a thylakoid lumen. Chloroplast thylakoids frequently form stacks of disks referred to as grana (singular: granum). Grana are connected by intergranal/stromal thylakoids, which join granum stacks together as a single functional compartment. In thylakoid membranes, chlorophyll pigments are found in packets called quantasomes. Each quantasome contains 230 to 250 chlorophyll molecules. Etymology The word ''Thylakoid'' comes from the Greek word ''thylakos'' or ''θύλακος'', meaning "sac" or "pouch". Thus, ''thylakoid'' means "sac-like" or "pouch-like". Structure Thylakoids are membrane-bound structures embedded in the chloroplast stroma. A stack of thylakoids is called a granum and resembles a stack of coins. Membrane The thylakoid membrane is the site of the ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-span (or bitopic) or multi-span (polytopic). Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barley
Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley production is used as animal fodder, while 30% as a source of fermentable material for beer and certain distilled beverages, and as a component of various foods. It is used in soups and stews, and in barley bread of various cultures. Barley grains are commonly made into malt in a traditional and ancient method of preparation. In 2017, barley was ranked fourth among grains in quantity produced () behind maize, rice and wheat. Etymology The Old English word for barley was ', which traces back to Proto-Indo-European and is cognate to the Latin word ' "flour" (''see corresponding entries''). The direct ancestor of modern English ''barley'' in Old English was the derived adjective ''bærlic'', meaning "of barley". The first citation of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
