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Cell (細胞)






Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Prokaryote
an organisms whose cells lack a membrane-bound nucleus (karyon)
Eukaryote
an organism whose cells contain a nucleus and organelles enclosed by membranes cell
Typical cells of prokaryotes and eukaryotes
Cell sizes
eukaryote (真核細胞)

animal cell: 25 μm (average)
young cell of seed plants: 5-25 μm
red blood cell: 7 μm
yeast: 6 μm

prokaryote (原核細胞)

E. coli: 1 μm (1 × 3 or 1.5 × 3 μm)
Streptococcus: 0.7 μm
Chlamydia: 300 μm
cowpox virus: 210 × 260 μm

Major components of cells

protoplasm (原形質)
karyoplasm* (核質)

nuclear membrane (核膜)
nuclear sap (核液)
chromatin (染色質/糸) → chromosome (染色体)
nucleolus (核小体)

cytoplasm (細胞質)

plasma membrane (形質膜)

cell membrane (細胞膜)

cytoplasm (細胞質)
mitochondria (ミトコンドリア)
ribosome (リボゾーム)
endoplasmic reticulum, ER (小胞体)

rough ER (粗面小胞体)
smooth ER (滑面小胞体) → microbody (ミクロボディ)

索引

Golgi apparatus (ゴルジ体)
lysosome (リソゾーム)
central body (中心体)
chromoplast (色素体), in particular, chloroplast (葉緑体)
ribosome (リボゾーム)
microtubule (微小管)

metaplasm (後形質)
= the nonliving matter or inclusions, as starch or pigments, within a cell
cell wall (細胞壁)
vacuole (液胞)
cell contents (細胞含有物)
* karyoplasm, karyoplast, or nucleoplasm cell
Plant cell structure

Cell wall (細胞壁)


wood chemistry (木材化学)

Comparisons with animal cell → animal cells do not have cell walls
Intercellular substance (細胞間物質) →
Animal cell = no cellulose
Plant cell = vegetal cellulose, hemicellular pectin, polysaccharide

glycocalyx (糖衣) = polysaccharide + glycocacidic polysaccharide
→ having the abilities on water suction, ion exchange, and cell recognition

Function
  • giving mechanical support
  • resisting turgor pressure
  • determining the growth and shape of the cell
  • strengthening the plant
  • influencing the apoplast transport
  • due to its certain components serving as nutritive depot
  • protecting the cell from mechanical and chemical influences
  • yielding signal molecules for itself and for interacting organisms
  • participating in cell-to-cell connections
Cell division
Plant cell: middle lamella (2 in Fig.) → primary wall (1)

Middle lamella: present between cells and acts as a cement preventing cells from migrating
cell

Animal cell: no cell wall → division
cell
Fig. Animal and plant cells
Plant cells are generally smaller than animal cells, due to vacuoles.
Components

Cell fusion (細胞融合)

cell → middle lamella (pectic subset, hemicellulose): working for cell adhesion
→ primary wall → administrating cellulase and pectinase after pulling apart cells
→ protoplast, spheloplast → cell fusion 1978 Melchers (Germany)

Cell fusion of tomato (Lycopersicon esculentum Mill.) and potato (Solanum tuberosum L.)
supposedly succeed in conjugation culture of potato

Vacuole (液胞)


1776 Spallanzani: contractile vacuoles firstly observed in protozoa
1841 Dujardin: named vacuoles
1842 Schleiden: applied vacuoles for plant cells
1885 de Vries: named the vacuoule membrane as tonoplast
A membrane-bound organelle that is present in all plant and fungal cells and some protist, animal and bacterial cells.
membrane

Plasma membrane (形質膜)


Unit membrane (単位膜)
Plasma membrane makes a separation between vacuole and cytoplasm

The structure of plasma membrane is similar with that of tonoplast

1895 Overton

the membreans are perviousness to water and oil → the mmembrean consists of the mosaic of lipids and proteins

1917 Langmuir: stearate → monolayer
1925 Gorter & Grende

the fats developed on the membrane surface of red blood cells consist of two molecules or sheets

1935 Danielli & Davson:

Sandwich model of plasma membrane

1950-60 Robertson

repeating unit theory(反覆単位説)
peripheral nerve of frog → KMnO4, potassium per mangnite
unit membrane: electrons insde of the membrane do not scatter
→ inside: electron less dense / oudside: dense
frog
Fig. Frog peripheral nerve

1960 Robertson

unit membrane (基本膜構造)

1960 Neville: sundy punch of structure and function of membrane

isolated the liver plasma membrane of rats by homogenization
membrane substances

fatty substrates + phospholipids + α-lecithin + β-lecithin = 40%
protein = 60%: most of them are structural proteins as enzymes
sugars: as glycoprotein in the plasma membrane

frog frog
R1: (CH2)16CH3, R2: (CH2)7-CH=CH-CH2-CH=CH-(CH2)4-CH3

sialic acid(シアル酸) and N-acethylneuraminic acid (NANA) are focused, because these substances are considered to be related to electrical characteristics of membrane surfaces

1964 Benzon

phase transition between protein and lipid → transition between crystal and liquid-crystal conditions
→ denied later

1966 Green

negative staining of mitochondria by heavy metals → membrane consisting of protein-lipid complex

1972 Singer SJ & Nicolson GL

fluid mosaic theory (流動モザイク説)

1974 Bretscher: utilized FMMP for probe (探針)

fmmp
FFMP (formyl methionyl methyl phosphate)
Characteristics:

• impermeability through cell membranes
• easily bonded with phospholipids (cell surface is bonded with glycoprotein and phospholipids)
• the presence inside or outside of membrane is known by radical phospholipids or not (indicating the bond with 35S)

→ phosphatidyl ethanol amine is present in the inside of membrane
phospholyase A: enzyme hydrolyzing phospholipids
intact cell: 50% of total phospholipods are hydrolyzed

Phosphalidyl choline _________ 70-80% ___ foming outside
Sphingomyelin ______________ 70-80%
Phosphatidhyl ethanol-amine _____ 20% ___ forming inside
Phsophatidhyl serine ____________ 0%

the inside is also hydrolyzed when ghost cells are used

Outside __ SM ___ PC
Insdie ____ PE ___ PS

FMMP-35S

1980 Bretscher et al.

intact red dry ghost: proteins → gel electrophoresis
gel electrophoresis of red cerp: intact red crep, ghost, proteins → gel electrophoresis
proteins etc. were separated by pore sizes → staining by commassie brilliant blue, amide black, etc.

    Band MW         Weight
    No   (dalton)   %
    1    24         15.7 ___ pectin
    2    21.5       14.7 ___ pectin
    2.1  20         -    ___ ankyrin
    3    8.8-8.9    24.1 ___ protein band #3
    4.1  7.8        4.2
    4.2  7.2        5.0
    5    4.3        4.5 ___ actin
    6    3.5        5.5
    7    2.9        3.4

Ex. much glycophorin (sugar) - commassie blue
60% sugar + 40% polypeptide (131 amino acids)
pAs staining (red) - pAs response
sugar chain is related to blood types and the field of binding with virus (influenza, hemagglutinating virus of Japan, etc.), and the field of recognizing lectin
pectin: penpheral protein extrinsic
ankyrin & band#3 protein: component A receptor
annnose 1: galactose 2: N-acetyl glucosamme 2
actin

Multiparticle model of cell membrane
Enzymatic activity
Na+-K+-ATPase: Ma++, Na+, K+ essential
adenyl cyclase: 5'-ATP → cAMP (cell aggregation occrus after certaion cells of cellular slime molds discharge cAMP)
Plasma membrane

Plasma membrane
chlorimecsterase

Plasma membrane

CH2-COR__________CH2OH
_|_______________→ |_______________+RCOOH + H2O
CH2-N+(CH3)3-OH-___CH2N+(CH3)3OH-

Sacarase: distributed in glycocalyx → polysaccharides are dissolved to monosaccharides → permeable sizes to membranes

sugar → glucose + fructose

Peroxidase
Monophenol (-OH), polyphenol
H2O2 + AH2 → 2H2O + A
AA oxidase (amino-acid oxidase, アミノ酸酸化酵素)

auxin(IAA)
dedol acetic acid

Selective permeability (選択的透過性)
1952 Theorell

plasma membrane
Ghost (可逆溶血法): GTP, UTP, ITP - the permeability of red blood is increased when the blood is lowered into water
The transports of Na+ and K+ go across when ATP is supplied into the membrane

1955 Hodgkin & Keynes

Giant axon(巨大軸索) of squid = giant nerve fiber
Na+ yield becomes low when cyan, azide, dinitrophenol(DNP) are given → oxidative phosphorylation
Na+ yield becomse high when ATP is supplied → ATP is required for sodium pump (Na pump)

1960 Coldwell

plasma membrane
K+ + Na+, lack K+ or Na+

1967 Skou

ATPase → the membrane is activated region =
ATP → [Mg++, Na+, K+] → ADP + Pi

1970 Whittam, et al.

1 molecule ATP
3Na+ atoms → pump out
2 K+ atoms → pump in

plasma membrane

A-P-P-32P + Na+ (in) + E1(ATPase) →
[Mg++] →
Na-E1-32P + ADP →
[K+, Mg++] → Na-E2-32P →
K+ + H2O + Na-E2-32P
⇔ E1 + Pi+
Na+ (outside), K+ (inside)

ATPase = 2.5-3.0 × 105 = subunits (large 1.0-1.3 × 105) + (small 0.5 × 105)

plasma membrane plasma membrane

couple (共載)
active transpport is performed by ATPase in the insdie of membrane

Cell membrane (細胞膜)


= protoplasmic membrane (formerly)
1970 Steck TL, Weinstein RS, Straus JH, Wallach DF

endocytosis
Endocytosis (エンドシトーシス, 飲細胞運動)): uptake

oragn or cell taking in nutrients → phagocytic vesicle

exocytosis
Exocytosis (エクソサイトーシス): evacuation

Endoplasmic reticulum, ER (小胞体)


Microtubule (微小管)


Centrosome (中心体)

Centriole (中心体)

1. Spindle body → connected in fiber formation

1956 Bernband: structure → globe → 5 μm = diameter of tublin

sprial tube is formed by 13 tubulins are aggregated

2. Basal body

present in flagellate (鞭毛虫) and ciliate (繊毛虫)
also found in Bryophytes and Pteridophytes
→ basal granule (keinetosomes, keineto nucleus (動原核), keinetoplast (毛基体)

9(3) + 2 → 9(3) + 3, 9(3) +1, 9(3) + 0

microtubule 3. Sperm tail: 9+2 → common
4. Spindle fiber

1968 Miki & Sakai (三木・酒井)

spindle fiber consisting of microbubules (confirmed by electron microscope)
Centrosome centriole

1952 Mzaia & Dan

mitotic apparatus (紡錘体、中心体) → extracted from sea urchin and observed

Non-basic protein RNA Polysaccharide
______95%______6%_______+

Spindle fiber consisting mostly of proteins (without DNA) 5. Microtubules

1963 Slantherbach: cnidoblasts of hydra
1963 Ledbetter & Porter: Phleum pratense
Echinosphuycrium (太陽虫)

1952, 56 Loewy, Nakajima

proteins in Physarum are actin (because of mobility) – rejected in the present

1953, 67 Kitching

spirally lined-up microtubles → each microtuble consisting of 12 subunits?

1966 Nagai (永井), Rebhum: Chara

Chara

50-100 filaments of which diameter is 50Å
→ also discovered from Physarum in 1976

Golgi body (ゴルジ体)


= Goldi apparatus, Golgi complex, dictyosome
1897 Golgi Camillo (Italian): identified the organella by a microscope

(called internal reticular apparatus) →
1988 the organella named after him in 1898

Function
Part of the cellular endomembrane system
→ packages proteins into membrane-bound vesicles

Mitochondria (ミトコンドリア)


1897 Benda Carl (1857-1932): discovered mitochondria
1900 Michaelis Leonor (1875-1949): discovered that mitochondria is strongly stained by janus green
1938 Bensley Robert R (1867-1956) & Bensley HS: Handbook of histological and cytological technique. University of Chicago Press

vital staining by janus green → micro-granules are specifically stained
also stained by janus red, dahlia violet, toluidine blue, methylene blue

rat liver: 800 mitochondria/cell
human 500-2500/cell
sperm 10-25/cell

1945 Lehninger: isolating mitochondria

isolated mitochondria + Pi (リン酸) + ADP + NADH → ATP

increasing permeability by soaking into hypotonic solution
O2-aerobic

producing ATP → the measurements clarified (3 ATP)/NADH
required dicarbonic acids (ジカルボン酸) and tricarbonic acids (トリカルボン酸) for NADH synthesis
required O2 for respiration

1948 Lehninger AL (1917-1986), et al.

RC particles, supported fluid mosaic model

1945-50 Lehninger: isolated mitochondria

NAD: nicotic acid adenine dinucleotide (coenzyme I, DPN+): coenzyme
NADP: nicotic acid adenine dinucleotide phosphoric acid (coenzyme II, TPN+)
flavin mononucleotide (FMN)
Ubiquinone (CoQ, UQ)
→ oxidation

Structure
mitochondria
mitochondria
Function
Energy generator
oxygen (aerobic) respiration = ATP synthesis

C6H12O6 + O2 → 12H2O + 6CO2 + 38ATP (688 kcal)

TCA cycle: present in matrix ⇔ electron transfer system: present in cristae

Vesicles (小胞)

mitochondria
Fig. ATP synthesis

1935 Szent-Györgyi: C4-dicarbonic acid cycle (now rejected)

1937 Krebs: TCA cycle (クレブス回路, クエン酸回路)

Chloroplast (葉緑体)


Plastid (色素体)

chloroplast is a kind of plastids
Chloroplast (葉緑体)
a double-membrane-bounded organelle containing elaborated membranous sacs known as thylakoids; the membranes contain chlorophyll a and other components of the photpsynthetic light reactions → chlorophyll (葉緑素)

phaeoplast (褐色体) in brown algae and blue-green algae → fucoxanthin (褐藻素)
rhodoplast (紅色体) → phycoerythrin (紅色素)

Chlomoplast (有色体): inter-cellular structure, not related photosynthesis
Leucoplast (白色体): not containing chlorophyll
Amyloplast (アミロプラスト): storing starch produced in chlorophyll
Proplastid (プロプラスチド): un-developed pigments
Phylogeny
The relationship between the phylogenetic development of photosynthetic apparatus and the system of classification in the plant kingdom
Eukaryotes (plastid)

Spermatophyta: Grana-and intergrana-thylakoid
Pteridophyta, Bryophyta, Charophyta: Granoid (ferns), pseudo-grana (moss and Charophyta), or multiple thylakoid
Euglenophyta, Phaeophyta, Pyrrophyta, Chrysophyta: Triple thylakoid
Cryptophyta: Double thylakoid
Rhodophyta: Single thylakoid

Prokaryotes (non-plastid)

Cyanophyta: Single or double thylakoid
Photosynthetic bacteria: Chromatophore or thylakoid

Structure

1953 Frey-Wyssling & Steinmann

quantasome (etymology, quantum 光量) = ca 200 × 100 100 Å (80-100 Å)
contents in quantasome: protein, lipid, chlorophyll, carothin, cytochrome, etc.

1957 Wettstein et al.

regularly-arranged vesicles
developing prolamella body and primary lamella
growing defects in the darkness

growing for four days in the darkness → lamella structure developed from prolamella body rapidly after exposure to light

Stages: proplastid → differentiation → maturation

Table. Dry weight (%) of chlorophyll content (Sinha 2004)

Proteins _______ 35-55 (half in lamella)

(Water soluble 20, Water insoluble 80)

Lipids _________ 20-30 (in lamella)
Carbohydrate ___ not constant (highly flctuated)
Pigments ______ 9 (as chlorophyll or kalotinoid)
Nucleic acids __ 2-3
+ NADP, NAD, FMN, FAD, ATP, ADP, NADPH2 and NADH2

chlorophyll
Granum (pl. -a): broadly defined as a stack(s) of thylakkoids within a chloroplast, such that the membranes of adjacent thylakoids are fused

Expression of gene information in chloroplasts

1883 Schimper & Meyer: Schimper and Meyer's theory

the concept of plastid continuity, stipulating that plastids do not arisee de nove but from preexisting plastids (葉緑体有親説)

1846 Näggeli:

all cells are coming from smaller cells = all chloroplasts are comoing from the chloroplasts

Nitella → mutants: the cells can not divide cells when the chloroplants are lost
observed the chloroplast division is synchronized with the nucleus division

1947 Eames & MacDoniels

proposed proplastid-origin theory → the structures of immature mitochondria are similar with the structures of proplastids
zygote in embryonic cell (初期胚) →

considered that the chloroplasts are developed from the proplastids through deforming from immature mitochondria

1959 Stocking & Gifford

Spirogyra, 3H-thymidine radio autography - confirming that chloroplast has DNA
high GC content for many plant species ⇔ DNA I: GC 60% = AT 40%, DNA II: GC 30% = AT 70%

1972 Kamashima & Wildman, 1972 Chan & Wildman

Chloroplast – maternal inheritance (母性遺伝)

Chloroplast RNA
RNA component: same with bacterial RNA
1954 Jagendorf & Wildman, 1957 Chiba & Sugawara (千葉 & 菅原)

confirmed that RNA is present in chloroplast

1962 Bandurskie & Maheshwari

14C-ATP: confirmed the synthesis of RNA polymerase ribosome

1964 Clark: ribosome consists of r-RNAs and proteins ribosome

83S, 68S ⇒ sucrose density-gradient centrifugation - centrifuged high molecules

S: sedimentation coefficient (沈降定数), S-value, proposed by Sverdverg)
large S = large particles (high molar weight)

ribosome in leaf = 83S, 68S ↔ ribosome in root = only 83S
→ probably 68S = mitochondrial ribosomes → size ≈ bacterial ribosome
t-RNA: specific in chloroplast ↔ different from t-RNA in nucleus amino acids (a.a.) + ATP + enzyme → aminoacyl-AMP + PP

enzyme: aninoacyl-t-RNA synthetase

a.a.-AMP-Et t-RNA → aminoacyl-t-RNA
∴ Chloroplast RNA = Bacterial RNA
→ if the RNA is bacteria origin → RNAs and enzymes are differnt from them in cytoplasm

1964 Spencer & Wildmann: Tobacco chloroplast →

the presence of t-RNA and synthetase shown by adding 14C-valine and ATP

1964 Kirk: Vicia faba (ソラマメ) chloroplast

RNA containing 14C is synthesized when 14C-ATP, GTP, CTP and UTP are added - evidence on the synthesis
RNA synthetase and RNA polymerase

1965 Sissakian et al.: pea seedling chloroplast

RNA extracted from the chloroplast is 3.25S

1965 Gunning: EM = polymer → synthesize proteins

centrifugal separation of ribosomes from chloroplast just before and after exposing light
before: polysomes are absent ↔ after: present
add 14C-a.a. to isolated chloroplants → 14C is absorbed into the proteins in the chloroplasts

Are all the gene information for producing proteins in chlorophyll present in hte chloroplast DNA?

chlorophyll DNA: 40 μm
Assuming that the molecular weiht of polypeptides is 20000, the information in chloroplast DNA is for 100-200 genes
→ sufficient to cover all the enyzmatic responses

1975 Keir & Mckman

RNA polymerase is absent in chloroplasts
RNA polymerases are absent in the chloroplasts and are produced in the nuculei → same with DNA polymerase

1980 Koessal: Euglena. 1980 Takaiwa & Sugiura: tobbaco

Determined the sequence of chloroplast DNA
sequence

Ribosome (リボゾーム)


Consisting of RNAc(60% RANs and 40% proteins in most cases) Ribosome particles: small subunit + large subunit
ribosome
Small and large subunits
               Large (× 106)   Small (× 106)
E. coli        1.1 (23S)        0.56 (16S)
Chloroplast    1.1              0.56
Yeast          1.24-1.30 (25S)  0.6-0.7 (17S)
Euglena        1.35 (24S)       0.85 (20S)
Higher plants  1.30 (25S)       0.70 (17-18S)

Mitochondrial ribosome

extracted from rat and Hela cells
→ confirmed 50-60S ribosomes: 39-45S = large subunit (16S RNA), 25-35S = small subunit (12S RNA)

cf. Yeast ribosome: 21S RNA + 15S RNA, Higher plants 26S + 18S

1971 Wu et al.

Hela's mitochondria → DNA, etc. → 16S RNA, 12S RNA
observed the RNAs after soaking into ferrum (Fe) by EM

Mitochondrial RNA: single strand
Cytochrome b, cytochrome oxidase complex, oligomycin-sensitive ATPase

Chloramphenicol – mitochondria origin (inhibiting protein synthesis)
Cycloheamoide – nucleus origin (inhibiting protein synthesis)

F1-ATPase: consisting of 10 subunits (5, 7, 8b and 9 originating from mitochondria)
RNA for producing enzymes related strongly to respiration (in mitochondria) are operated by nuculei, e.g.,malate dehydrogenase (MDH), isocitrate dehydrogenase (ICDH), β-hydroxybutyrate dehydrogenase, citrate dehydrogenase, and fumarate hydratase

Nucleus (細胞)


pl. nuclei
nuclei
Fig. Nuclear membrane
1957 Allfrey, Mirskey, & Osawa: confirmed that proteins are synthesized in the nuculeus

nuclei

Nucleolus ()

Chromosomes of Trillium kamtscaticum

observed that nucleoli remained in the three parts chromosome duirng mid-stage after heat treatment
→ secondary constriction was observed at the edge = probably nucleolus is distributed at the edge of chromosome
confirmed the similar locations were dyed by silver staining
→ conclusion: nucleolus is formed at specific locations in choromosome

Structure
the membrane of nucleolus can not be observed by EM
1860 Manthver → nucleolanema
1956 Estalle ett al. → nucleolous

two different structures in nucleolus - two patterns recognized by dye staining
vacuole (= nucleolus) or fibrous structure (= nucleolonema 仁糸)
inside: fibrons = RNA + proteins / outside: granular = ribosome-sized
→ nucleolus is considered to be precusor ribosomal particles condensed chromatin (=nucleolus associated chromatin): enclosed around nucleolus

Structural component
1950 Casperson: condensed chromatin named as nucleolus-associated chromain 1952 Vincent

egg cells of starfish →
RNA = 3-5%, proteins = 85-95%, DNA = 0 (recently shown to be 0.2-10%)

Nuclear substances (核質)

Nuclear substances or karyosome = 染色糸 + 核小体

chromatintin, nuclear sap, nucleolus, nuclear skeleton, nuclear vacuole

Chromatin (クロマチン)

Endosymbiosis (細胞内共生)


1905 Mereschkowsky C: chloroplasts in higher plants → anucleate amebas cohabit
1918 Portier P: mitochondria are intracellular symbionts
1927 Wallin IE: "Symbionticism and the origin of species"
1962, 63 Nass & Nass: colonial association theory

Structural and functional significance of bacteria and mitochondria
It has been, therefore, a constant source of encouragement and enlightenment for me to "rediscover" holistic concepts of mitochondria at a time when the observation of mitochondrial DNA fibrils was objected to, not on the basis of evidence presented, but because there was no obvious rationale for their presence. It was that, much to the dislike and must on occasion turn back in time to find original opinions on broad biological questions, because (a) our predecessors were here first, and (b) their brains were relatively uncultured to exercise their imagination.

endosymbiosis
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