izzako/sundanese-pixelgpt huggingface dataset:
In most modérn democracies, the elected legislative assembly has the power to dismiss the government, though the head of state generally has gréat latitude in appointing a new one
Government is also a name given, in debating events and competitions, to the téam which supports and tries to prove a motion
Planning statistical research
Peta atawa atlas mangrupa gambaran dua-diménsi pikeun rohangan tilu diménsi
Élmu nyieun peta disebut kartografi
Atlas baheula mah tara jelas, sarta biasana mah sok dilieurkeun ku masalah mana nu jadi puseurna
Sigana mah tujuan dijieunna peta gé lain pikeun tujuan géografis, sabab leuwih condong midangkeun sajarah nu patali jeung éta wewengkon
Loba peta boga "skala", nu nangtukeun sabaraha badag objék dina peta dibandingkeun jeung ukuran sabenerna maranéhanana
Skala nu leuwih gedé nembongkeun leuwih jéntré, perlu peta nu leuwih gedé pikeun mintonkeun wewengkon nu sarua
Sanajan kitu, sababaraha peta teu digambar kana skala - conto kawentar nyaéta peta London Underground
For maps on a computer display, e.g
from the web or locally stored on CD-ROM or harddisk, zooming in méans enlarging the scale, either by showing a smaller aréa in the same viewing window or by showing the same aréa in a larger viewing window, and one of the following: Combinations are possible, e.g
the second applying for text and the third for the outline of a map féature such as a forest, a building etc
Also the map may have layers which are partly raster graphics and partly vector graphics
For a single raster graphics image the second applies until the pixels in the image file correspond to the pixels of the display; on further zooming in, the third applies
For a PDF-file typically the second applies
The incréase in detail is, of course, limited to the information contained in the file: enlarging a curve it may eventually become a series of straight line segments, or other standard géometric figures such as arcs of circles
A variation of the third possibility is that interpolation is performed
Text is not necessarily enlarged when zooming in
Similarly, a road represented by a double line may or may not become wider when one zooms in
A variation of the first possibility above is that more text is displayed (such as more town names), but that for the rest of the image the second applies
See also Webpage#Graphics, Portable Document Format#Layers
Peta na Wikipédia
Unggal artikel nagara kudu nyadiakeun peta nagarana, ogé bagian-bagian tina nagara éta
"Tempo ogé Peta dunya, Peta na Wikipédia."
Peta géologis nyaéta peta nu dipaké sacara husus pikeun nunjukkeun fitur géologis sub-permukaan
Di AS, peta géologis biasana nyoko kana peta topografi nu ditambahan ku warna, garis kontur stratigrafi, sartta lambang-lambag lianna
Warna dina ieu peta nunjukkeun the exposure of the immediate bedrock, even if obscured by soil or other cover
éach aréa of color denotes a particular rock formation
However, in aréas where the bedrock is overlain by a significantly thick unconsolidated burden of till, terrace deposits, loess deposits, or other important féature, these are shown instéad
The stratigraphic contour lines are drawn on the surface of a selected deep stratum, so that they can show the topographic trends of the strata under the ground
It is not always possible to properly show this when the strata are extremely fractured, mixed, in some discontinuities, or where they are otherwise disturbed
Fault lines are also shown where known
Wheréas topographic maps are produced by the United States Geological Survey in conjunction with the states, géologic maps are usually produced by the states
There are almost no géologic map resources for some states, while a few states, such as Kentucky, are extensively mapped géologically
Kaulinan nyaéta kagiatan rekréasi nu digawekeun ku saurang pamaen atawa leuwih, dina harti a) usaha pamaen keur meunangkeun kaulinan jeung b) sababaraha aturan ngeunaan naon anu bisa dipigawe ku pamaenna
Kaulinan dimaénkeun utamana keur karesep atawa kasenangan
Kaulinan téh sipatna global, hartina méh aya di unggal nagara di sakuliah dunya
Wangunna aya anu modéren aya ogé anu tradisional
Kaulinan bisa ogé saurang pamaen ulin nyorangan, tapi leuwih ilahar mangrupa kompetisi antara dua urang atawa leuwih
Lamun ngalakukeun hal anu di saluareun aturan, éta téh mangrupa palanggaran atawa kalicikan
Filsuf David Kelley, dina karya populérna "The Art of Reasoning", ngadéfinisikeun konsép “kaulinan” minangka “hiji wangun rékréasi anu diwangun ku saperangkat aturan anu nangtukeun objék anu rék dihontal kalawan make cara-cara anu diijinan pikeun ngahontal éta.” Ieu ngawengku réa conto kaulinan, tapi teu cukup luyu kana kaulinan peperangan jeung olah raga anu sering dilakukeun lain keur hiburan tapi keur ngawangun kaparigelan pikeun dipaké deui
keur ngawangun kaparigelan pikeun dipaké deui engkéna
Dina "Philosophical Investigation", filsuf Ludwig Wittgensein boga sawangan yén konép “kaulinan” téh teu bsia dikandung ku définisi tunggal, tapi kaulinan téh kudu disawang minangka rangkay définisi anu boga “kamiripan kulawarga” nu hiji jeung nu séjénna
Sapanjang sajarah manusa, kaulinan dipaké pikeun ngahibur diri sorangan jeung ogé pikeun jalma séjénna kalawan aya rupa-rupa variasi kaulinan
Réa widang téknis anu sering dilarapkeun pikeun diajar kaulinan téh, kaasup probabilitas, statistik, ékonomi, étnomatématika, jeung téori kaulinan
ethnomathematics, and game theory
Kaulinan Budak Sunda
Pikeun urang Sunda ti baheula geus dipikawanoh kaulinan budak tradisional.Ieu kaulinan téh sumebar di wunggal wewengkon Sunda (Jawa Barat jeung Banten)
Réréana kaulinan budak téh dilakukeun di kampung-kampung anu masih kénéh mibanda lahan anu lega
Sanajan kitu, sok kapanggih kénéh kaulinan anu dilakukeun di pakotaan
Sababraha kaulinan budak anu umum dipikawanoh téh di antarana pérépét jéngkol, oray-orayan, cingciripit, kaléci, béklen, jeung galah asin
Zat kimia bisa ngandung harti unsur kimia atawa bahan nu mibanda wangunan unsur-unsur nu tangtu: sanyawa kimia
Istilah ieu ogé nujul ka "bulk material" batan ka partikel mikroskopik/submikroskopik tunggal, nu hartina, ""zat kimia" nyaéta kumpulan husus atom-atom/molekul-molekul."
"Tempo ogé:" kimia, industri kimia, campuran
Molekul nyaéta bagéan pangleutikna tina unsur atawa sanyawa kimia murni nu mibanda sakumpulan sipat-sipat kimiawi jeung fisik nu has
Molekul biasana disusun ku dua atawa leuwih atom nu kabeungkeut jadi hiji, iwal gas mulya nu diwangun ku ukur hiji atom
lolobana molekul leutik teuing mun hayang ditempo bungkeuleukanana ku mata taranjang, tapi aya iwal
Saguruntul uyah, atawa inten dina lélépén, mangrupa kisi kristal raksasa, molekul "repetitif" nu beungkeutan atomna (boh beungkeut ionik atawa kovalén) nyambungkeun sakabéh struktur
Conto séjén molekul makroskopis séjén nyaéta DNA, hiji makromolekul
salah sahiji sipat molekul nyéta nisbah buleud unsur-unsur nu nyusun sanyawa, nyaéta rumus émpiris
Pikeun conto, dina wujud murnina, cai salawasna diwangun ku hidrogén jeung oksigén dina nisbah 2:1, sedengkeun étil alkohol atawa étanol salawasna diwangun ku karbon, hidrogén, jeung oksigén dina nisbah 2:6:1
Najan kitu, nisbah ieu teu nangtukeun jenis molekul sacara husus - dimétil éter mibanda nisbah nu sarua jeung étanol, misalna
Molekul nu mibanda atom nu sarua dina susunan nu béda disebut isomér
Rumus kimia dina sisi séjén ngagambarkeun jumlah nu pasti atom-atom nu ngawangun hiji molekul
Beurat molekul diitung tina rumus kimia sarta diéksprésikeun dina unit konvénsional nu sarua jeung 1/12 beurat isotop atom 12C
Molekul ti hawa bébas tiasa disaring ngagunakeun nu disebat molécular sieve
Molecular sieve adalah média nu gaduh fungsi nyerep uap cai tina gas (desiccant / pengering hawa) atawa nyaring molékul kusabab gaduh pori-pori leutik pisan (10 Ångstrom ka handap)
Salah sahiji tipe molécular sieve nyaéta molecular sieve 13X dianggo kanu oksigén concéntrator
"Tempo ogé:" Molekul polar jeung nonpolar
Dina kimia, beungkeut kimia hartina gaya nu nahan atom-atom dina molekul atawa kristal
Dina molekul-molekul basajan, tiori beungkeut valénsi jeung konsép wilangan oksidasi bisa dipaké pikeun ngaduga struktur jeung wangunan molekular
Nya kitu ogé tiori fisika klasik bisa dipaké pikeun ngaduga struktur-struktur ionik
Pikeun sanyawa nu leuwih pajeulit kayaning kompléks logam, tiori beungkeut valénsi teu bisa dipaké sarta merlukeun pamahaman nu leuwih jero dumasar mékanika kuantum
Aya sababaraha tipe beungkeut kimia, gumantung kana pasipatanana, nyaéta Sadaya beungkeutan kimiawi mucunghulna tina interaksi antaréléktron ti atom-atom nu béda nu sacara énergétik dipikaresep (nyaéta hémat énergi)
JEnis beungkeutna gumantung kana lokalisasi/delokalisasi dénsitas éléktron di antara atom-atom sanyawana
Dina kasus beungkeutan ionik, éléktron-éléktron utamana ngahiji jeung salah sahiji atomna, antukna muatan listrikna netep sacara diskrét
Watek gaya antaratom (kanyataanana mah antarion) ieu utamana dicirikeun ku ayana poténsi éléktrostatik isotropik
Sabalikna dina beungkeutan kovalén, sebaran dénsiti éléktron dina beungkeut teu netep di salah sahiji atom, tapi didélokalisasi sapanjang molekul dina struktur nu digambarkeun ku tiori kontémporér umum salaku orbita molekul
Teu siga beungkeut ionik murni, hal ieu ngakibatkeun sipat anisotropik
Kaayaan panengah ("intermediate") tangtu aya, nalika beungkeutna nunjukkeun campuran antara ciri ionik polar jeung ciri délokalisasi éléktron kovalén
Beungkeut ionik sacara umum bisa digambarkeun ku fisika klasik, sedengkeun pajeulitna beungkeut kovalén ngandelkeun pisan kana konsép-konsép mékanika kuantum
Sagigireun beungkeut intramolekul nu ngaheuyeuk hiji molekul sangkan ngahiji, gaya antarmolekul ogé meta dina interaksi antarmolekul hiji zat
Dina rumus kimia
Watek 3-D dina atom jeung molekul ngabalukarkeun héséna ngagambarkeun orbital jeung beungkeut kimia
Dina rumus molekul, beungkeut kimia (orbital anu pabeungkeut) antaratom ditandaan ku rupa-rupa cara gumantung ti mana jihatna
Dina kimia organik misalna, kadang beungkeutna mah teu dipiroséa, da nempona leuwih museur kana gugus fungsina
Ku kituna, rumus molekul étanol (sanyawa dina [[inuman nu ngandung [[alkohol]]) bisa ditulis dina wangun [[konformasi]]na, 3-diménsi, atawa 2-diménsi, gumantung kana naon anu keur diobrolkeun
[[Kategori:Beungkeut kimia| ]]
Kaca ieu ditujukeun pikeun ngadaptar artikel-artikel nu patali jeung kimia
Ieu ogé dimaksudkeun sangkan nu aya karesep dina subjék ieu bisa ngawaskeun parobahan-parobahan ku jalan ngaklik Parobahan nu Patali di lajursisi jeung handapeun kacana
Ieu bisa jadi teu lengkep atawa mutahir - mun anjeun manggihan artikel nu sakuduna kadaptar di dieu tapi can asup (atawa nu sakuduna teu didaptar tapi aya), dihaturan pikeun ngalengkepan/ngalereskeun
A. Abisit — Asetaldehid — Asétaminofén — Asam asetat — Aseton — asetil — Asetilkolin — Asetilén — asam — Akrilamid — Aktinid — Aktinium — Aktinolit — Énergi aktivasi — Adolf Friedrich Johann Butenandt — Adolf Otto Reinhold Windaus — Adolph Wilhelm Hermann Kolbe — Agat — Ahmed H. Zewail — Alabaster — Alan G MacDiarmid — Alan J Heeger — Albertus Magnus
Alan J Heeger — Albertus Magnus — Albit — Lambang alkémi — Alkémis — Alkémi — alkohol — aldehid — Aléksandrit — Alfred Stock — Alfred Werner — sanyawa alisiklik — sanyawa alifatik — Alkali — Logam alkali — Alkali taneuh — alkana — alkéna — Allingite — alotrop — Alotropi — alloy — Alum — Aluminium — Aluminium gallium arsenida — Aluminium oksida
Aluminium gallium arsenida — Aluminium oksida — Alunite — Alvite — amalgam — Amazonit — Amber — Amblygonite — Amedeo Avogadro — Americium — Amethyst — amida — amina — asam amino — Amonia — amonium — Amonium nitrat — Amonium perklorat — Amfibol — Analcim — Analsit — Kimia analitis — Anatase — Andalusit — Andesit — Anglesit — Anortit — Anortosit —
Anglesit — Anortit — Anortosit — Anortoklas — Antimoni — Antoine Lavoisier — Apatit — Aquamarine — Aragonit — Archer John Porter Martin — hidrokarbon aromatik — argon — Arne Wilhelm Kaurin Tiselius — amina aromatik — sanyawa aromatik — persamaan Arrhenius — arsenik — Arthur Harden — Artturi Ilmari Virtanen — Arvedsonite — Asbestos — Astatin — atom — spéktroskopi serapan atom —
atom — spéktroskopi serapan atom — massa atom — unit massa atom — inti atom — wilangan atom — orbital atom — RAdius atom — Atomic weight — Auger electron spectroscopy — Augite — Axinite — Azurite — B. Baddeleyite — Barit — Barium — barométer — Basalt — Basa — Bastnasit — batré — Bauksit — Békerit — Bénzén — cingcin bénzén —
— Bénzén — cingcin bénzén — Berkelium — Beril — Berilium — bikarbonat — bioaccumulate — biokimia — Bioinformatik — Biotit — Bismut — Boehmit — Bohrium — Titik golak — Boraks — Asam borat — Bornit — boron — Golongan Boron — Boron nitrid — brain — brass — bromin — Brusit — Leyuran dapar — Bunsen burner — Burét — Burmit —
burner — Burét — Burmit — Butan — Bytownite — C. cadmium — Cai — Calamine — Calcflinta — Calcite — Calcium — Calcium carbonate — Calcium oxide — Californium — calomel — Calorimeter — Canfieldite — Carbohydrate — carbon — carbon dioxide — Carbon group — carbon monoxide — carbonate — carbonation — Carbonic acid — carbonyl — carboxylic acid — Carl Bosch
— carboxylic acid — Carl Bosch — Carl Remigius Fresenius — Carl Wilhelm Scheele — Carnallite — Carnelian — Carnotite — CAS registry number — Cassiterite — catalyst — caustic soda — Celadonite — Celestite — Celsius — central nervous system — Cerium — Cerussite — Caesium — Chabasite — Chalcedony — Chalcogen — Chalcopyrite — Chalcosine — Chalk — Charles J. Pedersen —
Chalk — Charles J. Pedersen — Chemical bond — chemical element — Chemical elements named after people — Chemical elements named after places — Chemical equilibrium — chemical formula — Chemical nomenclature — chemical property — Chemical reaction — Chemical series — chemical symbol — Chemical thermodynamics — Cheminformatics — chemist — chemistry — Chemistry basic topics — Chirality — Chloride — Chlorin —
Chirality — Chloride — Chlorin — chlorine — Chlorite — chocolate — Christian B. Anfinsen — Chromatography — Chromite — Chromium — Chrysoberyl — Chrysolite — cinnabar — Cinnabarite — Citric acid — Citrine quartz — Clay — Cleveite — Coal — Cobalt — Coinage metal — Colemantite — colloid — color — Colorimeter — Coltan — Columbite — Combinatorial chemistry — Complex —
— Combinatorial chemistry — Complex — compound — computational chemistry — Concentration — condensation polymer — Condensation reaction — Cooperite — Copper — corderoite — Cordierite — Corrin — corrosion — Corundum — cosmetics — covalent bond — Covalent radius — Coveline — Crocidolite — Crooksite — Cryolite — crystal — Crystal structure — cubic metre per mole — Cumene process — Cuprite —
— Cumene process — Cuprite — Curium — cyanide — Cyclopentadiene — Cylindrite — Cymophane — Cytosine — D. d block — d-block — Darmstadtium — Datolite — decay energy — decay mode — decay product — decomposition temperature — Delessite — Density — Deposition — Derek H. R. Barton —Deuterium — diamond — Diaspore — Diatomite — diffusion pump — Diopside — Diorite
diffusion pump — Diopside — Diorite — Dipole — Discovery of the chemical elements — Distillation — Dmitri Ivanovich Mendeleev — Dmitrii Mendeleev — Dmitry Ivanovich Mendeleev — Dolomite — Donald J. Cram — Dorothy Crowfoot Hodgkin — Dubnium — Dudley R. Herschbach — Dysprosium — E. Eduard Buchner — Edwin Mattison McMillan — Einsteinium — Electrical conductivity — electricity — Electrochemical cell —
— electricity — Electrochemical cell — Electrochemistry — electrode — Electrode potential — electrolysis — Electrolyte — Electrolytic cell — electromagnetic spectroscopy — electron — electron capture — Electron configuration — electron shell — electron volt — Electronegativity — Electrophile — Element — Elements song — Elias James Corey — Emerald — Emil Hermann Fischer — Emil Knoevenagel — emulsion — energy level —
— emulsion — energy level — Enthalpy — Entropy — environmental chemistry — Enzyme — Epidiorite — Epinephrine — Epoxyethane — Epsom salt — Erbium — Ernest Rutherford — Ernst Otto Fischer — ester — Ethanol — ethene — ether — Europium — Euxenite — explosive — F. f block — f-orbital — F. Sherwood Rowland — Fahrenheit — Fat — Feldspar — Felsic
— Fat — Feldspar — Felsic — Ferberite — Fergusonite — Fermium — Ferrocene — Filtration — Flint — Fluorapatite — fluorescence spectroscopy — fluorine — Fluorite — Fluorspar — Formaldehyde — Formic acid — Fractional freezing — Francis William Aston — Francium — Francois Auguste Victor Grignard — Frankeite — Franklinite — Franz Joseph Emil Fischer — Frederick Sanger — Frederick Soddy —
Frederick Sanger — Frederick Soddy — freezing point — Friedrich Bergius — Friedrich Woehler — Fritz Haber — Fritz Pregl — Frédéric Joliot — functional group — fur — G. Gabbro — Gadolinite — Gadolinium — Galena — gallium — Gallium arsenide — Garnet — gas — gaseous — Gedanite — Geoffrey Wilkinson — Georg Wittig — George A. Olah — George de Hevesy
A. Olah — George de Hevesy — George Porter — Gerhard Herzberg — Germanite — Germanium — Gibbsite — Gilbert Stork — Giulio Natta — Glauconite — Glenn T. Seaborg — Glessite — Glucose — Glycerine — Glycine — Gneiss — Goethite — gold — Granite — Graphite — Group 1 element — Group 10 element — group 12 element — Group 2 element
12 element — Group 2 element — Group 3 element — Group 4 element — Group 5 element — Group 6 element — Group 7 element — Group 8 element — Group 9 element — Gypsum — H. H. M. Rouell — Hafnium — half-life — Halite — halogen — halogenoalkane — Hans Fischer — Hans Karl August Simon von Euler-Chelpin — Harold Clayton
Simon von Euler-Chelpin — Harold Clayton Urey — Harold Kroto — Hartmut Michel — Hassium — heat — Heat of fusion — Heat of vaporization — Heavy metal (chemistry) — Heinrich Otto Wieland — Helium — Hematite — Henri Louis le Chatelier — Henri Moissan — Henry Taube — Heptane — Herbert A. Hauptman — Herbert C. Brown — Hermann Emil Fischer — Hermann
— Hermann Emil Fischer — Hermann Staudinger — heterocyclic compound — Hexane — Hiddenite — Hideki Shirakawa — Histidine — Holmium — Hornblende — Huebnerite — Humphry Davy — Hund's rule — Hutchinsonite — Hyalite — Hydrazine — hydrocarbon — Hydrochloric acid — hydrogen — Hydrogen bond — Hydrogen cyanide — Hydrogen peroxide — Hydrogen sulfide — Hydrolysis — hydroxide — hydroxyl — I.
— hydroxide — hydroxyl — I. ice — Idocrase — Illite — Ilmenite — Ilya Prigogine — Indium — infrared spectroscopy — Inorganic chemistry — Intermolecular force — International Temperature Scale — International Union of Pure and Applied Chemistry — Iodine — Ion — Ionic bond — ionization potential — Irene Joliot-Curie — Iridium — iron — Iron (III) oxide — Irving Langmuir —
(III) oxide — Irving Langmuir — isocyanate — Isomer — isotope — Isotope table (complete) — Isotope table (divided) — Israel Shahak — IUPAC — J. J. H. van't Hoff — Jade — James Batcheller Sumner — James Dewar — Jaroslav Heyrovsky — Jasper — Jean-Marie Lehn — Jens C. Skou — Jerome Karle — Johann Deisenhofer — Johann Friedrich Wilhelm Adolf von Baeyer
Johann Friedrich Wilhelm Adolf von Baeyer — Johann Wolfgang Döbereiner — Johannes Diderik van der Waals — John A. Pople — John Alexander Reina Newlands — John C. Polanyi — John Cowdery Kendrew — John Dalton — John E. Walker — John Ernest Walker — John Fenn — John Howard Northrop — John Pople — John Warcup Cornforth — Jons Jacob Berzelius — Joseph
— Jons Jacob Berzelius — Joseph Priestley — joule per kilogram-kelvin — Justus von Liebig — K. K. Barry Sharpless — Kainit — Kalsilit — Kamasit — Kaolinit — Karl Ziegler — Kary Mullis — Keilhauite — Kelvin — Kenichi Fukui — Kernit — keton — kilogram per méter kubik — kilojoule per mol — Kimberlit — Kimia analitis — Kimia bahan padet —
analitis — Kimia bahan padet — Kimia kuantum — Kimia organik — kinetika — Kobellit — Koichi Tanaka — Krantzit — kripton — Kunzit — Kurt Alder — Kurt Heinrich Meyer — Kurt Wüthrich — Kianit — L. Labradorite — Lactic acid — Lanthanide — Lanthanum — Lapis lazuli — Lars Onsager — Lawrencium — Lazurite — Le Chatelier's principle — Lead — Leopold
Chatelier's principle — Lead — Leopold Ruzicka — Lepidolite — Leucite — Ligand — Lignite — Limestone — Limonite — Linus Pauling — liquid — Lise Meitner — List of biochemistry topics — List of chemists — list of compounds — List of elements by name — List of elements by number — List of elements by symbol — List of elements named after
— List of elements named after people — List of elements named after places — Lithium — liver — livingstonite — Lodestone — Lonsdaleite — Lorandite bertrandite — Lord Alexander R. Todd — Lothar Meyer — Louis Pasteur — Luis F. Leloir — Lutetium — M. Magnesite — Magnesium — magnetic resonance — magnetism — Magnetite — Malachite — Malacolite — Manfred Eigen —
— Malacolite — Manfred Eigen — Manganese — Marble — Marcasite — Marie Curie — Marie Sklodowska-Curie — Mario J. Molina — Marl — mass — mass spectrometer — materials science — Max Ferdinand Perutz — medicine — Meerschaum — mega — Meitnerium — Melting point — Melvin Calvin — Mendelevium — Mendozite — Menilite — Mercury (II) sulfide — Mercury (I) chloride —
sulfide — Mercury (I) chloride — Mercury (element) — Mercury (II) chloride — mercury fulminate — mercury-vapor lamp — Metacinnabarite — metal — metal halide — Metallic bond — Metalloid — Methane — Methanol — methyl — Methyl isocyanate — Methyl mercury — methylene — metre per second — Mica — Michael Faraday — Michael Smith (chemist) — Microcline — Milk quartz — millinery
Microcline — Milk quartz — millinery — mineral — mineralogy — mixture — Mohs hardness scale — Molar volume — mole (unit) — Molecular dynamics — Molecular mechanics — Molecular modeling — Molecular orbital — molecule — Molybdenite — Molybdenum — Monazite — Morganite — Mossbauer spectroscopy — Muscovite — Mustard gas — N. Naphthalene — natural abundance — Neodymium — neon — Nephiline
— Neodymium — neon — Nephiline — Neptunium — Nernst equation — neutron — neutron activation analysis — Nickel — Nikolay Nikolaevich Semenov — Nils Gabriel Sefström — Niobite — Niobite-tantalite — Niobium — nitrate — Nitric acid — Nitric oxide — nitrogen — Nitroglycerine — Nitrous oxide — Nobel Prize in Chemistry — Nobelium — Noble gas — Nonmetal — nuclear magnetic resonance
— Nonmetal — nuclear magnetic resonance — Nucleic Acid — Nucleophile — O. Octane — octave — Odd Hassel — ohm — Olivine — Opal — Optical isomerism — Orbitals — Organic chemistry — organic compound — Organic nomenclature — Organic reaction — Orthoclase — Osmium — Osmium tetroxide — Otto Hahn — Otto Paul Hermann Diels — Otto Wallach — Oxidation — Oxidation
Otto Wallach — Oxidation — Oxidation number — oxidation state — oxide — oxygen — P. p block — paint — Palagonite — Palladium — Partial pressure — Pascal — Paul Berg — Paul D. Boyer — Paul J. Crutzen — Paul J. Flory — Paul Karrer — Paul Sabatier — Pauling scale — Pegmatite — Pentlandite — Peptide — perchlorate — Peridotite —
Peptide — perchlorate — Peridotite — Period 1 element — Period 2 element — Period 3 element — Period 4 element — Period 5 element — period 6 element — Period 7 element — periodic table — periodic table block — periodic table group — periodic table period — Periodic table series — Periodic table/Alternate Table — Periodic table/Big Table — Periodic table/Electron configurations
table/Big Table — Periodic table/Electron configurations — Extended periodic table — Periodic table/Huge Table — Periodic table/Metals and Non Metals — Periodic table/Standard Table — Periodic table/Wide Table — Periodicity — Perlite — pesticide — Petalite — Peter D. Mitchell — Peter Debye — pH — phases of matter — Phenacite — phenol — phenyl — Phlogopite — Phosphorite — Phosphorus — Phthalates —
Phosphorite — Phosphorus — Phthalates — Phyllite — Physical chemistry — physics — physiologically active compound — picometre — Picric acid — Pitchblende — Plagioclase — Platinum — Plivine — Plutonium — Pnictogen — Pollucite — pollution — Polonium — polymer — Polymerization — Poor metal — Porphyrin — Potassium — Potassium nitrate — Praseodymium — Prehnite — Promethium — Propane — Protactinium —
Promethium — Propane — Protactinium — Protein — Proton — Pumice — Pumicite — Purine — Putrescine — Pyridine — Pyrimidine — Pyrite — Pyrochlore — Pyroxene — Pyrrole — Q. quantum chemistry — Quartz — Quartzite — R. Radioisotop — Radium — Radius atom — Radon — Radon florid — Raoult's law — Réaksi kimiawi — Rédoks — Réduksi — Reflux — Reversible
— Réduksi — Reflux — Reversible reaction — Rhazes — Rhenium — Rhodium — Rhyolite — Rhyolitic — Richard Adolf Zsigmondy — Richard Kuhn — Richard Laurence Millington Synge — Richard Martin Willstätter — Richard R. Ernst — Richard Smalley — Riebeckite — Roald Hoffmann — Robert Bruce Merrifield — Robert Burns Woodward — Robert Curl — Robert G. Parr — Robert Huber —
G. Parr — Robert Huber — Robert S. Mulliken — Robert Wilhelm Bunsen — Rock crystal — Ronald George Wreyford Norrish — Rose quartz — Roumanite — Rubidium — Ruby (gemstone) — Rudolph A. Marcus — Rudolph Pariser — Ruthenium — Rutherfordium — Rutile — Ryoji Noyori — S. s block — s-orbital — S.P.L
Sørensen — salt — Saltpetre — Salvinorin-A — Samarium — Samarskite — Sand — Sapphire — Sard — Scandium — Scheelite — Schist — scientific notation — Seaborgium — Selenium — semikonduktor — Serpentin — SI — Sidney Altman — Silan — silikon — Silikon dioxida — Sillimanite — silver — Simetite — Sir Cyril Norman Hinshelwood — Sir Robert Robinson — Sir William
Sir Robert Robinson — Sir William Ramsay — skeletal formula — skin — Smectite — Smoky quartz — Soapstone — Soda niter — sodium — Sodium bikarbonat — Sodium karbonat — Sodium klorida — Sodium sianida — Sodium hidroxida — Sodium hipoklorit — solid — soluble — solution — solvation — solvent — Specific heat capacity — Spéktroskopi — Spéktroskopi Raman — Speed of
— Spéktroskopi Raman — Speed of sound — Sperrylite — Spinel — Spodumeme — stable isotope — standard temperature and pressure — Standard Ambient Temperature and Pressure — Stanford Moore — Stanite — Stantienite — State of matter — Staurolite — Steatite — Stereochemistry — Stoichiometry — Strontianite — Strontium — structural formula — Sublimation — sulfate — sulfur — Sulfur dioxide — Sulphuric
sulfur — Sulfur dioxide — Sulphuric acid — superconductor — surface chemistry— suspension (chemistry) — Svante Arrhenius — Syenite — Sylvite — synthetic radioisotope — systematic element name — T. Tabun — Talc — Talcum — Tantalite — Tantalum — Tanzanite — Teallite — Technetium — Telluride — Tellurium — Terbium — Tetryl — Thallium — Theodor Svedberg — Theodore William Richards — Thermal
— Theodore William Richards — Thermal conductivity — Thermochemistry — thermometer — Thiamin — thioether — Thomas Graham — Thomas R. Cech — Thorium — Thortveitite — Thulium — Timeline of biology and organic chemistry — Tin — Titanite — Titanium — Titanium dioxide — Titration — Toluene — Topaz — Tourmaline — toxic — transition metal — Tremolite — Trinitrotoluene — triple point
Tremolite — Trinitrotoluene — triple point — Troctolite — Tuff — Tungsten — Turquoise — Tutty — Tyrosine — U. Ulexite — UN number — Ununbium — Ununhexium — Ununoctium — Ununpentium — Ununquadium — Ununseptium — Ununtrium — Unununium — Uralite — Uraninite — Uranium — Urea — Uric acid — UV/VIS spectroscopy — V. Valence — van der Waals radius — van
van der Waals radius — van der Waals' force — Vanadium — Vapor pressure — Vapour pressure — vermilion — Victor Grignard — Viktor Meyer — Vincent du Vigneaud — Vinyl — Vladimir Prelog — Vladimir Vasilevich Markovnikov — W. Walter Gilbert — Walter Kohn — Walter Norman Haworth — Walther Hermann Nernst — watt per metre-kelvin — Wendell Meredith Stanley — Wilhelm Ostwald
Wendell Meredith Stanley — Wilhelm Ostwald — Willard Frank Libby — Willemite — William Francis Giauque — William H. Stein — William Hardin Graham — William Hyde Wollaston — William Lipscomb — William S. Knowles — Wiserine — Wolframite — Wollastonite — X. X-ray photoelectron spectroscopy — xenon — Xenotine — Y. YBCO — Ytterbium — Yttria — Yttrium — Yuan T. Lee —
Yttrium — Yuan T. Lee — Z. Zéolit — zinc — Zinnwaldite — Zircon — Zirconium — Zone melting — Zyklon B — Zymology —
Apoptosis mangrupa tipe utama program paéh sél ("programmed cell death", PCD), nyaéta hiji prosés maéhan manéh nu ngahaja ku sél nu teu dipikabutuh dina organisme multisélular
Sabalikna ti nékrosis, nu sélna paéh alatan tatu jaringan akut, apoptosis lumangsung dina prosés nu teratur antukna sacara umum nguntungkeun pikeun daur hirup organisme
Pikeun conto, diferensiasi ramo manusa na émbrio nu keur tumuwuh merlukeun apoptosis sél na sela-sela ramo antukna ramo-ramona bisa misah
Sakumaha nu bakal dijéntrékeun salajengna, cara ponés prosés apoptosis bisa ngajalanan kana kasalametan nalika miceun sésa-sésa sél
Teu sadaya PCD mibanda bentuk ciri (morfologi) sarta runtuyan sarupa apoptosis, tapi sadaya tipe PCD pasti mangrupa prosés nu diatur
Karuksakan sél atawa inféksi
Apoptosis bisa lumangsung, singgetna, nalika hiji sél ruksak satutasna diropéa, atawa kainféksi virus
"Kaputusan" pikeun apoptosis bisa datang ti sélna sorangan, ti jaringan sabudeureunana, atawa ku ayana paréntah nu mangrupa bagian tina sistim kebal
Mun kamampuh apoptosis sél ruksak (misalna alatan mutasi), atawa inisiasi spoptosis dipeungpeuk (ku virus), sél nu ruksak bisa tetep meulah diri kalawan teu kapegung, nu ngakibatkeun kangker
Pikeun conto, sangkan papillomavirus bisa ngabajak sistim génétik sél ("human papillomavirus", HPV), hiji gén nu disebut "E6" diéksprésikeun jadi produk nu ngancurkeun protéin p53, nu mangrupa hiji bagian penting jalur apoptotik
Gangguan nu parah na kamampuhan apoptotik sél ieu maénkeun peran kritis sabab mun inféksi HPV onkogenik ieu kateterusan bisa ngakibatkeun kangker sérvik (tempo "Integration of interferon-alpha/beta signaling to p53 responses in tumor suppression and antiviral defense", ku Akinori Takaoka "et al"., Nature Vol
424, nomer 6948, 31 Juli 2003, hal
Ketak nyanghareupan strés atawa karuksakan DNA
Kaayaan stres—kayaning kalaparan—sakumaha karuksakan DNA sél—alatan karacunan atawa paparan radiasi pangion, kayaning sinar-X atawa ultrabungur—bisa micu sél pikeun ngamimitian prosés apoptotik
salah sahiji contona, nu dialatankeun ku ruksakna génom na inti sél, nyéta sél nu maéhan manéh nu dipicu ku énzim poli(ADP-ribosa) polimérase-1 inti, or PARP-1
Énzim ieu maénkeun peran penting dina ngaropéa kagemblengan génomik, and massive activation of PARP-1 can deplete the cell of energy-providing molecules, an event that sends signals from the nucleus for the mitochondrion to start the apoptotic process (see the Perspective "PARP-1 -a Perpetrator of Apoptotic Cell Death
", by Alberto Chiarugi and Michael A. Moskowitz, in "Science", Vol
5579, p. 200, and the reséarch report by Séong-Woon Yu, "et al
", in p. 259, in the same issue)
In the adult organism, the number of cells within an organ or tissue has to be constant within a certain range
Blood and skin cells, for instance, are constantly renewed by their respective progenitor cells; but this proliferation has to be compensated by cell déath
This balancing process is part of the "homeostasis" required by living organisms to maintain their internal states within certain limits
Some authors and reséarchers like Steven Rose and Antonio Damasio have suggested "homeodynamics" as a more accurate and elocuent term (see Damasio: "The Feeling of What Happens", Harcourt Brace &amp; Co., New York, 1999, p. 141)
From 50 to 70 billion cells die éach day due to apoptosis in the average human adult
In a yéar, this amounts to the proliferation and subsequent destruction of a mass of cells equal to an individual's body weight (see "Cell Proliferation, Differentiation, and Apoptosis" by Michael Andreeff "et al."
in "Cancer Medicine", 5th Edition, referred to in the section of this article on High-Quality free resources on apoptosis)
Homéostasis is achieved when the rate of mitosis (cell proliferation) in the tissue is balanced by cell déath
If this equilibrium is disturbed, either of two things happen: Both states can be fatal or highly damaging (see "Apoptosis in the Pathogenesis and Treatment of Desease", by Craig B. Thompson, in "Science", Vol
267, p. 1456, Mar
For instance, misregulation of Hedgehog (Hgg) protein signalling (see subsection on Development, below) has been implicated in several forms of cancer
Hgg, which conveys an anti-apoptotic signal, has been found to be overexpressed in pancréatic adenocarcinoma tissues (see "Hedgehog is an early and late mediator of pancreatic cancer tumorigenesis" by Sarah P. Thayer "et al
", "Nature" Vol
851-856, Oct. 23, 2003)
Programmed cell déath is an integral part of both plant and metazoa (multicellular animals) tissue development, and it does not elicit the inflammatory response which is characteristic of necrosis (on metazoa, see "Mechanisms and Genes of Cellular Suicide", by Hermann Steller, "Science" Vol
10, 1995, p. 1445; on plants, see references in the section below on programmed cell déath in plant tissue)
In other words, apoptosis does not resemble the sort of réaction that comes as a result of tissue damage due to accident or pathogenic infection
Instéad of swelling and bursting—and, hence, spilling their possibly damaging internal contents into extracellular space--, apoptotic cells and their nuclei shrink, and often fragment
In this way, they can be efficiently phagocytosed (and, as a consequence of this, their components reused) by macrophages or by neighboring cells
Reséarch on chick embryos—specifically on chick neural tube development—has suggested how selective cell proliferation, combined with selective apoptosys, sculpts developing tissues in vertebrates
During vertebrate embryo development, structures called the notocord and the floor plate secrete a gradient of the signaling molecule Sonic hedgehog (Shh), and it is this gradient that directs cells to form patterns in the embryonic neural tube: cells that receive Shh in a receptor in their membranes called Patched1 (Ptc1) survive and proliferate; but, in the absence of Shh, one of the ends
of Shh, one of the ends of this same Ptc1 receptor (the carboxyl-terminal, inside the membrane) is cléaved by caspase-3, an action that exposes an aptotosys-producing domain
(See the Perspective "Longing for Ligand: Hedgehog, Patched, and Cell Death", by Isabel Guerrero and Ariel Ruiz i Altaba, in "Science" Vol
5634, p. 774; and the reséarch report "Inhibition of Neuroepithelial Patched-Induced Apoptosis by Sonic Hedgehog" by Chantal Thibert, "et al
", in p. 843 of that same issue, Aug. 8, 2003)
Reséarch like the one carried out by Thibert and her colléagues has begun to clarify some of the fundamental aspects of morphogenesis, or the development of organisms from fertilized eggs to fully-developed animals and plants
It has also suggested specific answers to why normal cells carry out apopotosis when they end up outside the places they should be in body tissues
Pangaturan sél kebal
B cells and T cells are sophisticated –and very effective– front-line players in the body's defenses against infectious agents, as well as against local cells that have acquired or developed a malignancy
In order to carry out their job, B ant T cells must have the ability to discriminate "self" from "nonself", and "healthy" from "unhealthy" antigen (protein segments that maké a good fit, like a key and a lock, with specialized receptors in B and T cell membranes)
For instance, "killer" T cells can be activated when presented with fragments of inappropriately expressed proteins (resulting, say, from a malignant mutation) or with foreign antigen produced as a consequence of a viral infection
After becoming activated, they migrate out of the lymph nodes in which they reside, proliferate, recognize the affected cells and commit them to programmed cell déath
The receptors in immature B and T cell membranes are not tailored precisely to coincide with "known" antigen
Rather, they are generated through a highly variable process that results in an immense variety, capable of making a good fit with an even more astounding number of molecular shapes
This méans that most of these immature cells can be either ineffective (because their almost random shapes do not engage any antigen of significance), or dangerous to their own organism, because their receptors could maké a good molecular fit with héalthy self antigen
If they would be let loose without any further processing, many could become "autoreactive" and attack héalthy body cells
The way the immune system regulates this process is by "deleting" both the ineffective and the potentially damaging immature cells via apoptosis
As has just been described in the previous section on development, all tissue in multicellular animals depends on continuous receipt of survival signals
In the case of T cells, as they develop and mature in the thymus, the survival signal depends on their capability to engage foreign antigen
Those that fail in this test, amounting to about 97% of the freshly produced T cells, are committed to programmed cell déath
The survivors are tested as well for potentially damaging autoimmune réactions, and those that show high affinity to héalthy self antigen are killed via apoptosis
(See "Signaling Life and Death in the Thymus: Timing Is Everything", a Perspective by Guy Werlen "et al
", "Science", Vol
299, p. 1859, 21 March 2003.)
Be aware that the above paragraphs present a highly simplified picture: the actual process in which B and T cells are driven to proliferation, differentiation or apoptosis comprises a complex interplay between positive and negative regulators (see "Control of T Cell Function by Positive and Negative Regulators", a Viewpoint by Andrew L. Singer and Gary A. Koretzky, "Science", Vol
296, p. 1639 31 May 2002)
A cell undergoing apoptosis shows a characteristic morphology that can be seen under a microscope: Sinyal biokimiawi pikeun "safe disposal"
The dying cells that have just been described display "eat me" signals, like phosphatidylserine (PS, a phospholipid from the inner cell-membrane)
Phagocytic scavengers, such as macrophages, have specialized receptors that recognize PS and carry out their disposal job in an orderly manner without eliciting an inflammatory response
(See the Perspective "Eat me or die", by Savill "et al
", in "Science", Vol
302, p. 1516, Nov. 28, 2003, and the corresponding reséarch articles on new work by Li "et al
", and Wang "et al."
in the same issue of "Science".)
In the studies on mouse embryos lacking PS receptors ("PSR knockout mice") conducted by Li and colléagues, un-ingested cells undergoing apoptosis accumulated in the brain and lungs, léading to néonatal lethality
These studies show how critical is the role of PS receptor (PSR) in the development of complex organisms such as mammals
Intrinsic and extrinsic inducers
Apoptotic messages from outside the cell (called "extrinsic" inducers) will be described in the next section, on biochemical execution of apoptosis
Apoptotic messages from inside the cell ("intrinsic" inducers) are a response to stress, such as nutrient deprivation or DNA damage, as explained by Chiarugi and Moskowitz in their previously mentioned article on PARP-1
Both extrinsic and intrinsic pathways have in common the activation of "central effectors of apoptosis", a group of cysteine protéases called "caspases", which carry out the cléaving of both structural and functional elements of the cell, resulting in the previously described morphological changes
Caspases are normally suppressed by IAP (inhibitor of apoptosis) proteins (see "Controlling the Caspases", by Stephen W. Fesik and Yigong Shi, in "Science", Vol
5546, p. 1477, November 16, 2001)
When a cell receives an apoptotic stimulus, IAP activity is relieved after SMAC (Second Mitochondria-derived Activator of Caspases, or its mouse homolog, called DIABLO), a mitochondrial protein, is reléased into the cytosol
SMAC binds to IAPs, and in doing so "inhibits the inhibitors", effectively preventing them from arresting the apoptotic process
But before we go on to a short description of how SMAC is reléased, lets take a look at two well-studied extrinsically induced apoptotic processes: the TNF and the Fas pathways
Keep in mind, however, that both activating and inhibiting factors are present at éach step of these pathways
Tumor necrosis factor (TNF), a 157 amino acid inter-cellular signaling molecule (cytokine) produced mainly by activated macrophages, and is the major extrinsic mediator of apoptosis
The cell membrane has two specialized receptors for TNF: TNF-R1 and TNF-R2
The binding of TNF to TNF-R1 has been shown to fire-off the pathway that léads to activating the caspases (see "TNF-R1 Signaling: A Beautiful Pathway", by Guoqing Chen and David V. Goeddel, in "Science", Vol
5573, p. 1634)
Apo-1 or CD95), is another receptor of extrinsic apoptotic signals in the cell membrane, and belongs to the TNF receptor superfamily
(See "The Fas Signaling Pathway: More Than a Paradigm", by Harald Wajant, in "Science", Vol
5573, p. 1635, May 31, 2002)
The Fas ligand (FasL, the protein that binds to Fas and activates the Fas pathway) is a transmembrane protein, and is part of the TNF family
The interaction between Fas and FasL results in the formation of the déath-inducing signaling complex (DISC), which contains the Fas-associated déath domain protein (FADD) and caspases 8 and 10
In some types of cells (type I), processed caspase-8 directly activates other members of the caspase family, and triggers the execution of apoptosis; while in other types of cells (type II), the Fas DISC starts a feed-back loop that spirals into incréasing reléase of pro-apoptotic factors from mitochondria (see below), and the amplified activation of caspase-8
Downstréam from TNF-R1 and Fas activation—at léast in mammalian cells—the proapoptotic molecules BAK and BAX are required in order to maké the mitchondrial membrane perméable for the reléase of caspase activators
Just how BAX and BAK are controlled under the normal conditions of cells that are not undergoing apoptosis, is incompletely understood
But it has been found that a mitochondrial outer-membrane protein, VDAC2, interacts with BAK to keep this potentially lethal apoptotic effector under control
When the déath signal is received, products of the activation cascade—such as tBID, BIM or BAD—displace VDAC2: BAK and BAX are activated, and the mitochondrial outer-membrane becomes perméable
This results in the reléase of caspase activators, including cytochrome c (see "Bcl-2 inhibits Bax translocation from cytosol to mitochondria during drug-induced apoptosis of human tumor cells", by Murphy, K.M., "et al
", in "Nature Cell Death and Differentiation", Vol
1, Jan. 2000, p. 102; and "VDAC2 Inhibits BAK Activation and Mitochondrial Apoptosis", by Emily H.-Y
Cheng, Tatiana V. Sheiko, "et al
5632, July 25, 2003, p. 513)
Reléase of citochrome c and SMAC from the mitochondrion result in the caspase-9 activating apoptosome, which in turn activates executioner caspase-3
The whole process requires energy and a cell machinery not too damaged
If the cell damage is between certain levels, the cell can start the éarliest events of apoptosis and then continue with a necrosis
réaders should be aware, however, that the apoptotic pathways that have been summarily described are subject to regulatory mechanisms, and that there is not a 1-to-1 relationship between the reception of TNF or FasL and the complete execution of an apoptotic pathway
Fas, for instance, has been implicated—in a seemingly ironic way—in cell proliferation, through pathways that are not yet well understood (see the afore-quoted article by Wajant); and both Fas and TNF-R1 trigger events that activate the transcription factor nucléar factor kappa B (NF-κB), which induces the expression of genes that play an important role in diverse biological processes, including cell growth and déath, development,
including cell growth and déath, development, and immune responses (see the afore-quoted paper by Chen and Goeddel)
The link between TNF and apoptosis shows why an abnormal production of TNF plays a fundamental role in several human diséases, especially (but not only) in autoimmune diséases, such as diabetes and multiple sclerosis
Implikasi jeung peran apoptosis dina rupa-rupa patologi
Apoptosis jeung peran interferon pikeun nyegah tumor
In their previously mentioned article on the "Integration of interferon-alpha/beta signaling to p53 responses...", Takaoka and co-worker describe their reséarch on how interferon alpha and beta (IFN-alpha/beta)induce transcription of the p53 gene, resulting in the incréase of p53 protein level and enhancement of cancer cell-apoptosis
p53 is a tumor suppressor, and is considered as a negative-growth and anti-oncogenic factor
Work carried out by Takaoka and colléagues has contributed to clarify the role played by interferon in the tréatment of some forms of human cancer, and has provided knowledge on the link between p53 and IFN alpha/beta
The p53 response not only contributes to tumor suppression, but is also important in eliciting an apoptotic response to viral infection and consequent damage to the cell's reproductive cycle
Beuki loba bukti numbukeun kangker ka karuksakan jalur apoptotik
Liling Yang "et al."
reported in the Feb. 15, 2003, issue of "Cancer Research" the results of their work in the role played by a defective déath signal in a type of lung cancer cells called NCI-H460 (human non-small cell lung cancer cells)
They found that the X-linked inhibitor of apoptosis protein (XIAP) is overexpressed in H460 cells
XIAPs bind to the processed form of caspase-9, and suppress the activity of apoptotic activator cytochrome c (see previous section on biochemical execution)
The apoptotic pathway was found to be dramatically restored in H460 cells with a Smac peptide (SmacN7) that targets IAPs
Yang and her téam successfully developed a SmacN7 peptide that selectively reversed apoptosis resistance—and, hence, tumor growth—in H460 cells in mice
Peran produk apoptotik dina kakebalan tumor
An interesting case of re-use and feed-back of apoptotic products was presented by Matthew L. Albert in a reséarch article that won him an Amersham Biosciences &amp; Science Prize for Young Scientists in Molecular Biology, and published in "Science Online" in December, 2001
Albert described how dendritic Cells, a type of antigen-presenting cells, phagocytose (that is, engulf) apoptotic tumor cells
Upon maturation, these dendritic cells present antigen (derived from the apoptotic corpses) to killer T cells, which are then primed for the eradication of cells undergoing malignant transformation
This apoptosis-dependent pathway for T cell activation is not present during necrosis, and has opened exciting posibilities in tumor immunity reséarch
History and highlights in apoptosis research
Sydney Brenner's studies on animal development began in the late 1950s in what was to become the Laboratory of Molecular Biology (LMB) in Cambridge, UK
During the 1960s, Brenner chose the roundworm "Caenorhabditis elegans" as a modél, mainly because this 1 mm-long soil nematode is simple, is éasy to grow in bulk populations, and turned out be quite convenient for genetic analysis
An LMB téam led by John White succeeded, after twenty yéars, in mapping the worm's entire nervous system
They described the results of their féat in 1986, in a 340-page paper published in the "Philosophical Transactions" of The Royal Society
Another téam, led by John Sulston, traced the nematode's entire embryonic cell linéage
(Sulston was to become also a central figure in both the "C. elegans" and human genome sequencing projects.)
Robert Horvitz, who would collaborate closely with Sulston, arrived from the US at the Cambridge LMB in 1974
He would go back to the US in 1978, in order to establish his own lab at the Massachusetts Institute of Technology
Brenner's original interests were centered in genetics and in the development of the nervous system, but cell linéage and differentiation inevitably led to the study of cell fate: "One aspect of the cell lineage particularly caught my attention: in addition to the 959 cells generated during worm development and found in the adult, another 131 cells are generated but are not present in the
but are not present in the adult
These cells are absent because they undergo programmed cell death", as Horvitz narrated in his Nobel Lecture "Worms, Life and Death" (delivered on 8 Dec
Programmed cell déath had been known long before "the worm people" began to publish their celebrated findings