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1.
Blixt O Vasiliu D Allin K Jacobsen N Warnock D Razi N Paulson JC Bernatchez S Gilbert M Wakarchuk W 《Carbohydrate research》2005,340(12):1963-1972
We have synthesized several ganglio-oligosaccharide structures using glycosyltransferases from Campylobacter jejuni. The enzymes, alpha-(2-->3/8)-sialyltransferase (Cst-II), beta-(1-->4)-N-acetylgalactosaminyltransferase (CgtA), and beta-(1-->3)-galactosyltransferase (CgtB), were produced in large-scale fermentation from Escherichia coli and further characterized based on their acceptor specificities. 2-Azidoethyl-glycosides corresponding to the oligosaccharides of GD3 (alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp-), GT3 (alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp-), GM2 (beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-), GD2 (beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-), GT2 (beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->8)-alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-), and GM1 (beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-) were synthesized in high yields (gram-scale). In addition, a mammalian alpha-(2-->3)-sialyltransferase (ST3Gal I) was used to sialylate GM1 and generate GD1a (alpha-D-Neup5Ac-(2-->3)-beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1-->4)-[alpha-D-Neup5Ac-(2-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-) oligosaccharide. We also cloned and expressed a rat UDP-N-acetylglucosamine-4'epimerase (GalNAcE) in E. coli AD202 cells for cost saving in situ conversion of less expensive UDP-GlcNAc to UDP-GalNAc. 相似文献
2.
L. D. Matyakhina M. G. Colonin S. D. Pack P. M. Borodin J. B. Searle O. L. Serov 《Mammalian genome》1996,7(4):265-267
This report extends the genetic map of the common shrew (Sorex araneus) by adding chromosome assignments for ten genes to the seven already mapped (Pack et al. 1995). A somatic cell hybrid panel
was used for the mapping. The genes for peptidase A (PEPA) and isocitrate dehydrogenase-1 (IDH1) map to chromosome de; the genes for phosphoglucomutase-1 (PGM1), superoxide dismutase-1 (SOD1), and mannosephosphate isomerase (MPI) are located on chromosome af; the genes for nucleoside phosphorylase (NP) and glutathione reductase (GSR) are on chromosome ik; and the genes for peptidase S (PEPS), malic enzyme-1 (ME1), peptidase B (PEPB) are found on chromosomes jl, go, and mp respectively.
Received: 2 October 1995 / Accepted: 21 November 1995 相似文献
3.
We have determined and compared trace metals concentration in saliva taken from chemical warfare injures who were under the exposure of mustard gas and healthy subjects by means of inductively coupled plasma optical emission spectroscopy (ICP-OES) for the first time. The influence of preliminary operations on the accuracy of ICP-OES analysis, blood contamination, the number of restored teeth in the mouth, salivary flow rate, and daily variations in trace metals concentration in saliva were also considered. Unstimulated saliva was collected at 10:00–11:00 a.m. from 45 subjects in three equal groups. The first group was composed of 15 healthy subjects (group 1); the second group consisted of 15 subjects who, upon chemical warfare injuries, did not use Salbutamol spray, which they would have normally used on a regular basis (group 2); and the third group contained the same number of patients as the second group, but they had taken their regular medicine (Salbutamol spray; group 3). Our results showed that the concentration of Cu in saliva was significantly increased in the chemical warfare injures compared to healthy subjects, as follows: healthy subjects 15.3± 5.45(p.p.b.), patients (group 2) 45.77±13.65, and patients (Salbutamol spray; group 3) 29 ±8.51 (P <0.02). In contrast, zinc was significantly decreased in the patients, as follows: healthy subjects 37 ± 9.03(p.p.b.), patients (group 2) 12.2 ± 3.56, and patients (Salbutamol spray; group 3) 20.6 ±10.01 (P < 0.01). It is important to note that direct dilution of saliva samples with ultrapure nitric acid showed the optimum ICP-OES outputs. 相似文献
4.
N-Nitrosodimethylamine (NDMA) is an emerging contaminant of concern. N-nitrodimethylamine (DMNA) is a structural analog to NDMA. NDMA and DMNA have been found in drinking water, groundwater, and other media and are of concern due their toxicity. The authors evaluated biotransformation of NDMA and DMNA by cultures enriched from contaminated groundwater growing on benzene, butane, methane, propane, or toluene. Maximum specific growth rates of enriched cultures on butane (μmax = 1.1 h?1) and propane (μmax = 0.65 h?1) were 1 to 2 orders of magnitude higher than those presented in the literature. Growth rates of mixed cultures grown on benzene (μmax = 1.3 h?1), methane (μmax = 0.09 h?1), and toluene (μmax = 0.99 h?1) in these studies were similar to those presented in the literature. NDMA biotransformation rates for methane oxidizers (υmax = 1.4 ng min?1 mg?1) and toluene oxidizers (υmax = 2.3 ng min?1 mg?1) were comparable to those presented in the literature, whereas the biotransformation rate for propane oxidizers (υmax = 0.37 ng min?1 mg?1) was lower. NDMA biotransformation rates for benzene oxidizers (υmax = 1.02 ng min?1 mg?1) and butane oxidizers (υmax = 1.2 ng min?1 mg?1) were comparable to those reported for other primary substrates. These studies showed that DMNA biotransformation rates for benzene (υmax = 0.79 ng min?1 mg?1), butane (υmax = 1.0 ng min?1 mg?1), methane (υmax = 2.1 ng min?1 mg?1), propane (υmax = 1.46 ng min?1 mg?1), and toluene (υmax = 0.52 ng min?1 mg?1) oxidizers were all comparable. These studies highlight potential bioremediation methods for NDMA and DMNA in contaminated groundwater. 相似文献
5.
2-Dimethylaminomethylene-1-benzosuberone 1 was coupled with diazotized aniline derivatives to afford a series of the hitherto unreported 2-arylazo-1-benzosuberones 3a–i. The tautomeric structure and the effect of substituents on the tautomeric form (s) of the products 3a–i were discussed. Similar coupling of the enaminone 1 with diazonium salts of heterocyclic amines gave the respective fused azolotriazino-benzosuberones. Some of the newly synthesized compounds showed potent antimicrobial, anti-HCV, antioxidant, antitumor (as topoisomerase I inhibitors), and antimicrobial activities. 相似文献
6.
Synthesis,Chemical Characterization,DNA Binding,Antioxidant, Antibacterial,and Antifungal Activities of Ferrocence Incorporated Selenoureas 下载免费PDF全文
Raja Azadar Hussain Amin Badshah Muhammad Nawaz Tahir Tamoor‐ul‐ Hassan Asghari Bano 《Journal of biochemical and molecular toxicology》2014,28(2):60-68
Ferrocene‐incorporated selenoureas 1‐(4‐methoxybenzoyl)‐3‐(4‐ferrocenylphenyl)selenourea (P4Me), 1‐(3‐methoxybenzoyl)‐3‐(4‐ferrocenylphenyl)selenourea (P3Me), and 1‐(2‐methoxybenzoyl)‐3‐(4‐ferrocenylphenyl)selenourea (P2Me) were synthesized and characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, atomic absorption spectroscopy, CHNS, and single‐crystal X‐ray diffraction. DNA interaction of the compounds was investigated with cyclic voltammetry, UV–visible spectroscopy, and viscometry, which is a prerequisite for anticancer agents. Drug‐DNA binding constant was found to vary in the sequence: KP4Me (4.9000 × 104 M?1) > KP2Me (2.318 × 104 M?1) > KP3Me (1.296 × 104 M?1). Antioxidant (1,1‐diphenyl‐2‐picrylhydrazyl), antifungal (against Faussarium solani and Helmentosporium sativum), and antibacterial (against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis) activities have also been reported in addition. 相似文献
7.
Reaction of 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl trichloroimidate with allyl alpha-D-mannopyranoside in the presence of TMSOTf selectively gave allyl 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl-(1-->6)-alpha-D-mannopyranoside through an orthoester intermediate. Benzoylation of 3, followed by deallylation, and then trichloroimidation afforded the disaccharide donor 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl trichloroimidate, while benzoylation of 3 followed by selective removal of acetyl groups yielded the disaccharide acceptor allyl alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranoside. Coupling of 5 with 6 gave the tetrasaccharide allyl 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranoside, which were converted into the tetrasaccharide donor 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl trichloroimdate and the tetrasaccharide acceptor allyl alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-mannopyranoside, respectively, by the same strategies as used for conversion of 3 into 5 and 6. Condensation of 5 with 13 gave the hexasaccharide 14, while condensation of 12 with 13 gave the octasaccharide 17. Dodecasaccharide 21 was obtained by the coupling of 12 with the octasaccharide acceptor 20. Similar strategies were used for the syntheses of beta-(1-->6)-linked glucose di-, tri-, tetra-, hexa-, and octamers. Deprotection of the oligosaccharides in ammonia-saturated methanol yielded the free alpha-(1-->6)-linked mannosyl and beta-(1-->6)-linked glucosyl oligomers. 相似文献
8.
J. B. Sutherland J. P. Freeman A. J. Williams 《Applied microbiology and biotechnology》1998,49(4):445-449
Streptomyces viridosporus T7A (ATCC␣39115), during growth in tryptone/yeast extract broth, cometabolized five heterocyclic nitrogen-containing compounds.
The metabolites produced from the azaarenes were identified by high-performance liquid chromatography, UV/visible absorption
spectroscopy, and mass spectrometry. Isoquinoline was transformed to 1(2H)-isoquinolinone (14%), phenanthridine to 6(5H)-phenanthridinone (25%), phthalazine to 1(2H)-phthalazinone (46%), quinazoline to 2,4(1H,3H)-quinazolinedione (4%), and quinoxaline to 2(1H)-quinoxalinone (8%) and 1-methyl-2(1H)-quinoxalinone (12%).
Received: 29 July 1997 / Received revision: 19 November 1997 / Accepted: 29 November 1997 相似文献
9.
In the presence of suitable acceptor molecules, dextransucrase makes a homologous series of oligosaccharides in which the isomers differ by a single glucosyl unit, whereas alternansucrase synthesizes one trisaccharide, two tetrasaccharides, etc. For the example of maltose as the acceptor, if one considers only the linear, unbranched possibilities for alternansucrase, the hypothetical number of potential products increases exponentially as a function of the degree of polymerization (DP). Experimental evidence indicates that far fewer products are actually formed. We show that only certain isomers of DP >4 are formed from maltose in measurable amounts, and that these oligosaccharides belong to the oligoalternan series rather than the oligodextran series. When the oligosaccharide acceptor products from maltose were separated by size-exclusion chromatography and HPLC, only one pentasaccharide was isolated. Its structure was alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->4)-D-Glc. Two hexasaccharides were formed in approximately equal quantities: alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->4)-D-Glc and alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->4)-D-Glc. Just one heptasaccharide was isolated from the reaction mixture, alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->4)-D-Glc. We conclude that the enzyme is incapable of forming two consecutive alpha-(1-->3) linkages, and does not form products with more than two consecutive alpha-(1-->6) linkages. The distribution of products may be kinetically determined. 相似文献
10.
Li Xu Nan-Jing Zhong Hong-Liang Huang Zhen-Hua Liang Zheng-Zheng Li Yun-Jun Liu 《Nucleosides, nucleotides & nucleic acids》2013,32(8):575-591
Two new ruthenium(II) polypyridyl complexes [Ru(dmb)2(HECIP)](ClO4)2 (1) (HECIP = N-ethyl-4-[(1,10)-phenanthroline(5,6-f)imidazol-2-yl]carbazole, dmb = 4,4’-dimethyl-2,2’-bipyridine) and [Ru(dmp)2(HECIP)](ClO4)2 (2) (dmp = 2,9-dimethyl-1,10-phenanthroline) have been synthesized and characterized. The DNA-binding behaviors of the two complexes were investigated by absorption spectra, viscosity measurements, and photoactivated cleavage. The DNA-binding constants for complexes 1 and 2 were determined to be 8.03 (± 0.12) × 104 M?1 (s = 1.62) and 2.97 (± 0.15) × 104 M?1 (s = 1.82), respectively. The results suggest that these complexes interact with DNA through intercalative mode. The photocleavage of pBR322 DNA by Ru(II) complexes was investigated. The cytotoxicity of complexes 1 and 2 has been evaluated by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide)] method. Complex 1 shows higher anticancer potency than 2 against the four tumor cell lines. Apoptosis and cellular uptake were investigated. The antioxidant activities of the ligand and these complexes were also performed. 相似文献
11.
Kenya Touyama Masud Khan Kazuhiro Aoki Miho Matsuda Fumitaka Hiura Nana Takakura Takuma Matsubara Yui Harada Yuna Hirohashi Yukihiko Tamura Jing Gao Kayo Mori Shoichiro Kokabu Hisataka Yasuda Yuko Fujita Koji Watanabe Yoshinori Takahashi Kenshi Maki Eijiro Jimi 《Journal of cellular biochemistry》2019,120(11):i-i
Skeletal tissue homeostasis is maintained via the balance of osteoclastic bone resorption and osteoblastic bone formation. Autophagy and apoptosis are essential for the maintenance of homeostasis and normal development in cells and tissues. We found that Bax-interacting factor 1 (Bif-1/Endophillin B1/SH3GLB1), involving in autophagy and apoptosis, was upregulated during osteoclastogenesis. Furthermore, mature osteoclasts expressed Bif-1 in the cytosol, particularly the perinuclear regions and podosome, suggesting that Bif-1 regulates osteoclastic bone resorption. Bif-1-deficient (Bif-1 −/−) mice showed increased trabecular bone volume and trabecular number. Histological analyses indicated that the osteoclast numbers increased in Bif-1 −/− mice. Consistent with the in vivo results, osteoclastogenesis induced by receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) was accelerated in Bif-1 −/− mice without affecting RANKL-induced activation of RANK downstream signals, such as NF-κB and mitogen-activated protein kinases (MAPKs), CD115/RANK expression in osteoclast precursors, osteoclastic bone-resorbing activity and the survival rate. Unexpectedly, both the bone formation rate and osteoblast surface substantially increased in Bif-1 −/− mice. Treatment with β-glycerophosphate (β-GP) and ascorbic acid (A.A) enhanced osteoblastic differentiation and mineralization in Bif-1 −/− mice. Finally, bone marrow cells from Bif-1 −/− mice showed a significantly higher colony-forming efficacy by the treatment with or without β-GP and A.A than cells from wild-type (WT) mice, suggesting that cells from Bif-1 −/− mice had higher clonogenicity and self-renewal activity than those from WT mice. In summary, Bif-1 might regulate bone homeostasis by controlling the differentiation and function of both osteoclasts and osteoblasts (235 words). 相似文献
12.
Mark R. Ibberson John P. Copier Elena Llop Cristina Navarrete Adrian V. S. Hill J. Kennedy Cruickshank A. K. L. So 《Immunogenetics》1997,47(2):124-130
Interactions involving the T-cell receptor (TCR) and major histocompatibility complex (MHC) are fundamental to the generation
of a specific immune response. The study of interpopulation differences in TCR genes may identify those genes which are subject to selection, and also provides useful information for future genetic studies
in these populations. In this study we present analysis of five TCRAV polymorphisms, for V5S1, V6S1, V8S1, V17S1, and V21S1 loci in five human populations by single-strand conformational polymorphism (SSCP) analysis. Caucasian, Chinese, Gambian,
AfroCaribbean, and South American Indians (Mapuches) showed marked interpopulation variation for both the silent (V5S1, V17S1, and V21S1) and coding (V6S1 and V8S1) polymorphisms. In general the alleles were conserved in the different populations, but new, additional variants were found
for V5S1 and V17S1 in Gambians and Caucasians. V6S1 overall showed the highest nucleotide diversity, and V6S1 genotype distributions were skewed away from expected values in Chinese and Mapuches. Analysis of allelic associations showed
a general lack of linkage disequilibrium between the loci, which was reflected by the absence of strong population-specific
haplotypes.
Received: 22 April 1997 / Revised: 9 July 1997 相似文献
13.
The structures of four new saponins, polyphyllin C, D, E and F, isolated from the tubers of Paris polyphylla have been elucidated as diosgenin-3-O-α-l-rhamnopyranosyl(1→3)-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→3)- [α-l-arabinofuranosyl(1→4)]-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→2)-α-l-rhamnopyranosyl (1→4)[α-l-rhamnopyranosyl(1→3)]-β-d-glucopyranoside and diosgenin-3-O-α-l-rhamnopyranosyl(1→4)[α-l- rhamnopyranosyl(1→3)][β-d-glucopyranosyl(1→2)]-α-l-rhamnopyranoside, respectively, on the basis of chemical and spectral data. 相似文献
14.
Sandra L. Schmid Alexander Sorkin Marino Zerial 《Cold Spring Harbor perspectives in biology》2014,6(12)
Endocytosis may have been a driving force behind the evolution of eukaryotic cells. It plays critical roles in cell biology (e.g., signal transduction) and in organismal physiology (e.g., tissue morphogenesis).Endocytosis, the process of cellular ingestion, may have been the driving force behind evolution of the eucaryotic cell (de Duve 2007). Acquiring the ability to internalize macromolecules and digest them intracellularly would have allowed primordial cells to move out from their food sources and pursue a predatory existence; one that might have led to the development of endosymbiotic relationships with mitochondria and plastids. Thus, it is fitting that endocytosis was first discovered and named as the processes of cell “eating” and “drinking.” In 1883, the developmental biologist Ilya Metchnikoff coined the term phagocytosis, from the Greek “phagos” (to eat) and “cyte” (cell), after observing motile cells in transparent starfish larva surround and engulf small splinters that he had inserted (Tauber 2003). Decades later, in 1931, Warren H. Lewis, one of the earliest cell “cinematographers” coined the term pinocytosis, from the Greek “pinean” (to drink), after observing the uptake of surrounding media into large vesicles in cultured macrophages, sarcoma cells, and fibroblasts by time-lapse imaging (Lewis 1931; Corner 1967).Importantly, these pioneering studies also revealed that the function of endocytosis goes well beyond eating and drinking. Indeed, Metchnikoff, considered one of the founders of modern immunology, realized that the phagocytic behavior of the mesodermal amoeboid cells he had observed under the microscope could serve as a general defense system against invasive parasites, in the larva as in man. This revolutionary concept, termed the phagocytic theory, earned Metchnikoff the 1908 Nobel Prize in Physiology or Medicine for his work on phagocytic immunity, which he shared with Paul Ehrlich who discovered the complementary mechanisms of humoral immunity that led to the identification of antibodies (Vaughan 1965; Tauber 2003; Schmalstieg and Goldman 2008). The phagocytic theory was a milestone in immunology and cell biology, and formally gave birth to the field of endocytosis.Key discoveries over the intervening years, aided in large part by the advent of electron microscopy, revealed multiple pathways for endocytosis in mammalian cells that fulfill multiple critical cellular functions (Fig. 1). These mechanistically and morphologically distinct pathways, and their discoverers, include clathrin-mediated endocytosis (Roth and Porter 1964), caveolae uptake (Palade 1953; Yamada 1955), cholesterol-sensitive clathrin- and caveolae-independent pathways (Moya et al. 1985; Hansen et al. 1991; Lamaze et al. 2001), and, more recently, the large capacity CLIC/GEEC pathway (Kirkham et al. 2005). In place of Metchnikoff’s splinters, many of these discoveries resulted from the detection and tracking of internalized HRP-, ferritin-, or gold-conjugated ligands by electron microscopy. These electron-dense tracers allowed researchers to identify cellular structures associated with the uptake and intracellular sorting of receptor-bound ligands. A particularly striking example is the pioneering work of Roth and Porter, who in 1964 observed the uptake of yolk proteins into mosquito oocytes. To synchronize uptake, they killed female mosquitos at timed intervals after a blood feed and observed the sequential appearance of electron-dense yolk granules in coated pits, coated and uncoated vesicles, and progressively larger vesicles. Their remarkable observations accurately described coated vesicle budding, uncoating, homo- and heterotypic fusion events, as well as the emergence of tubules from early endosomes (Fig. 2), all of which are now known hallmarks of the early endocytic trafficking events.Open in a separate windowFigure 1.Time line for discoveries of endocytic pathways and their discoverers. Boxes are color-coded by pathway. *, Nobel laureate. HRP, horseradish peroxidase; CCVs, clathrin-coated vesicles; CCPs, clathrin-coated pits; EGFR, epidermal growth factor receptor; PM, plasma membrane; ER, endoplasmic reticulum; CLIC/GEEC, clathrin-independent carriers/GPI-enriched endocytic compartments.Open in a separate windowFigure 2.Fiftieth anniversary of the discovery of clathrin-mediated endocytosis by Roth and Porter (1964). The image is the hand-drawn summary of observations made by electron microscopic examination of the trafficking of yolk proteins in a mosquito oocyte. Note the many details, later confirmed and mechanistically studied over the intervening 50 years. These include the growth, invagination, and pinching off of coated pits (1,2), which concentrate cargo taken up by coated vesicles (3), the rapid uncoating of nascent-coated vesicles (4), homotypic fusion of nascent endocytic vesicles in the cell periphery (5), the formation of tubules from early endosomes (7), and changes in the intraluminal properties of larger endosomes (6). Finally, yolk proteins are stored in granules as crystalline bodies (8). (From Roth and Porter 1964; reprinted, with express permission, from Rockefeller University Press © 1964, The Journal of Cell Biology
20: 313–332, doi: 10.1083/jcb.20.2.313.)Another milestone in the field of endocytosis was the discovery of the lysosome by Christian de Duve (Appelmans et al. 1955). Whereas the finding of phagocytosis and other endocytic pathways was possible through microscopy, the discovery of lysosomes originated from a biochemical approach (Courtoy 2007), which benefited from the invention of the ultracentrifuge. de Duve and coworkers observed that preparations of acid phosphatase obtained by subcellular fractionation had an unusual behavior: contrary to most enzymatic activities, the activity of acid phosphatase increased rather than decreased with time, freezing–thawing of the fractions and the presence of detergents. Interestingly, the same was true for other hydrolases, which depended on acidic pH for their optimal activity. This led him to postulate that the acid hydrolases were contained in acidified membrane-bound vesicles. In collaboration with Alex Novikoff, he visualized these vesicles, the lysosomes, by electron microscopy (Beaufay et al. 1956) and later showed their content of acid phosphatase (Farquhar et al. 1972). In 1974, de Duve was awarded the Nobel Prize for Physiology or Medicine for his seminal finding of the lysosomes and peroxisomes. He shared it with Albert Claude and George E. Palade “for their discoveries concerning the structural and functional organization of the cell.” The importance of this work lies also in the significant therapeutic applications that followed. The discovery by Elizabeth Neufeld and collaborators of uptake of lysosomal enzymes by cells provided the foundation for enzyme replacement therapy for lysosomal storage disorders (Neufeld 2011).In the 1970s, research in endocytosis entered the molecular era. Using de Duve and Albert Claude-like methods of subcellular fractionation, Barbara M. Pearse purified clathrin-coated vesicles from pig brain (Pearse 1975). A year later, she isolated a major protein species of 180 kDa, which she named clathrin “to indicate the lattice-like structures which it forms” (Pearse 1976). It was a breakthrough that inaugurated the molecular dissection of clathrin-mediated endocytosis.Over the intervening years, the continued application of microscopy (which now spans from electron cryotomography to live cell, high-resolution fluorescence microscopy), genetics (in particular, in yeast, Caenorhabditis elegans and Drosophila melanogaster), biochemistry (including cell-free reconstitution of endocytic membrane trafficking events), as well as molecular and structural biology have revealed a great deal about the cellular machineries and mechanisms that govern trafficking along the endocytic pathway. A partial, and because of space limitations, necessarily incomplete list of milestones (Year Mechanistic milestones Discoverers 1973 Identification of shibirets (dynamin) mutant in Drosophila D. Suzuki and C. Poodry 1974–1976 Zipper mechanism for phagocytosis S. Silverstein 1975–1976 Isolation of CCVs, purification of clathrin B. Pearse 1982–1984 Phosphomannose, M6PR, and lysosomal targeting W. Sly, S. Kornfeld, E. Neufeld, G. Sahagian 1983–1984 Isolation of clathrin adapters/localization to distinct membranes J. Keen, B. Pearse, M. Robinson 1986 Isolation of endocytosis mutants (End) in yeast H. Riezman 1986–1987 Isolation of vacuolar protein sorting mutants in yeast S. Emr, T. Stevens 1986 Endosome fusion in vitro J. Gruenberg and K. Howell 1986 EGF and insulin receptor signaling from endosomes J. Bergeron and B. Posner 1986 Macropinocytosis induced in stimulated cells D. Bar-Sagi and J. Feramisco 1987 Endocytic sorting motifs (FxNPxY, YxxF) M. Brown and J. Goldstein, I. Trowbridge, T. McGraw 1987–1989 Cloning of CHC, CLC, AP2 T. Kirchhausen, M. Robinson 1988 Isolation of biochemically distinct early and late endosomes S. Schmid and I. Mellman 1989–1991 Clathrin-mediated endocytosis reconstituted in vitro E. Smythe, G. Warren, S. Schmid 1990 Localization of endosomal Rab5 and Rab7 P. Chavrier, R. Parton, M. Zerial 1991 Endosome to trans-Golgi network (TGN) transport reconstituted in vitro S. Pfeffer 1992 Rab5 and Rab4 as early endocytic regulators in vivo M. Zerial, R. Parton, I. Mellman 1992–1995 Caveolin/VIP21 identified as caveolar coat protein R. Anderson, T. Kurzchalia, R. Parton, K. Simons 1992 Vacuolar fusion reconstituted in vitro W. Wickner 1992–1994 Trigger mechanism for phagocytosis of bacteria S. Falkow, J. Galán, J. Swanson 1993 Actin’s role in endocytosis in yeast H. Riezman 1993 Isolation of autophagy mutants (Atg) in yeast Y. Ohsumi 1993 PI3 kinase activity (PI3P) and endosome function S. Emr 1993 Dynamin’s role in clathrin-mediated endocytosis R. Vallee, S. Schmid 1995 Dynamin assembles into rings S. Schmid, P. De Camilli 1996 Clathrin-mediated endocytosis requirement for signaling S. Schmid 1996 Long distance retrograde transport of signaling endosomes in neurons W. Mobley 1996 PI5 phosphatase activity (PI(4,5)P2) and clathrin-mediated endocytosis P. De Camilli 1996 Ubiquitin-dependent sorting in endocytosis R. Haguenauer-Tsapis; L. Hicke and H. Riezman 1997 AP3 and endosomal/lysosomal sorting J. Bonifacino, S. Robinson 1998 FYVE fingers bind to PI3P H. Stenmark 1998 LBPA in MVB biogenesis T. Kobayashi, R. Parton, J. Gruenberg 1997–1998 Sorting nexins G. Gill, S. Emr 1998 Structural basis for Y-based sorting signal recognition D. Owen 1998 Retromer coat and endosome to TGN sorting S. Emr 1998 β-Propeller structure of clathrin heavy chain terminal domain T. Kirchhausen and S. Harrison 1998 Cargo-specific subpopulations of clathrin-coated pits M. von Zastrow 1999 Structure of the clathrin coat protein superhelical motifs J. Ybe and F. Brodsky 1999 Imaging green fluorescent protein–clathrin in living cells J. Keen 1999 Biochemical purification of Rab5 effectors S. 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