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51.
52.
Isolation of Vacuoles from Immature Apple Fruit Flesh and Compartmentation of Sugars, Organic Acids, Phenolic Compounds and Amino Acids 总被引:4,自引:0,他引:4
Vacuoles of immature apple fruit (Malus pumila Mill. var. domesticaSchneid.) were obtained by purification using Ficoll densitygradient centrifugation after lysis of the protoplasts by bothmild osmotic shock and the addition of EDTA and BSA. The recoverywas about 35% of the protoplasts. The isolated vacuoles hada mean diameter of about 100 µm. The distribution of sugars, organic acids, phenolic compoundsand amino acids in the vacuole, the cytoplasm and the free spacewas determined. Almost all of the fructose and glucose, themajor sugars of the tissue, were found in the vacuole. Sorbitolwas mainly located in the free space and the vacuole, and sucrosein the free space and the cytoplasm. More than 90% of the malicacid, the main organic acid, was located in the vacuole. Almostall of the phenolic compounds were also deposited in the vacuole. The volumes of the vacuole, the cytoplasm and the free spacein the whole tissue were calculated from the cell numbers ofthe whole tissue, the volume of the isolated protoplasts, andthe volume of the vacuoles present in the protoplast. The soluteconcentration in each compartment was estimated: vacuoles, 888mM; cytoplasm, 37 mM; free space, 57 mM. How these compartmentationsof solutes affected the translocation of sugars into the fruitand the cell expansion is discussed.
1This paper is contribution A-159 of the Fruit Tree ResearchStation. (Received July 7, 1983; Accepted November 14, 1983) 相似文献
53.
Cranial placodes are specialized ectodermal regions in the developing vertebrate head that give rise to both neural and non-neural cell types of the neuroendocrine system and the sense organs of the visual, olfactory and acoustic systems. The cranial placodes develop from a panplacodal region which is specifically marked by genes of the eyes absent/eya and two “six homeobox” family members (sine oculis/six1 and six4). It had been believed that cranial placodes are evolutionary novelties of vertebrates. However, data from non-vertebrate chordates suggest that placode-like structures evolved in the chordate ancestor already. Here, we identify a morphological structure in the embryonic head of the beetle Tribolium castaneum with placode-like features. It is marked by the orthologs of the panplacodal markers Tc-six4, Tc-eya and Tc-sine oculis/six1 (Tc-six1) and expresses several genes known to be involved in adenohypophyseal placode development in vertebrates. Moreover, it contributes to both epidermal and neural tissues. We identify Tc-six4 as a specific marker for this structure that we term the insect head placode. Finally, we reveal the regulatory gene network of the panplacodal genes Tc-six4, Tc-eya and Tc-six1 and identify them as head epidermis patterning genes. Our finding of a placode-like structure in an insect suggests that a placode precursor was already present in the last common ancestor of bilaterian animals. 相似文献
54.
Calmodulin purified from bovine brain markedly stimulated cyclic GMP-dependent protein kinase from pig lung in the presence of cyclic GMP. This stimulation by calmodulin did not require Ca2+ and was dose-dependent up to optimal amounts, but the extent of stimulation decreased at concentrations over the optimal condition. The concentrations of cyclic GMP and cyclic AMP producing half-maximal stimulation were 4.5 × 10?8 M and 5.0 × 10?6 M respectively, under optimal conditions. Calmodulin increased maximum velocity without altering the Km for ATP. These effects of calmodulin on cyclic GMP-dependent protein kinase were similar to those of the stimulatory modulator described by Kuo and Kuo (J. Biol. Chem. , 4283–4286, 1976). Ouf findings indicate that calmodulin regulates enzyme activity both Ca2+-dependently and independently. 相似文献
55.
Soo Lim Jeong Hongyu Zhang Shanni Yamaki Chenyu Yang David
D McKemy Michael
R Lieber Phuong Pham Myron
F Goodman 《Nucleic acids research》2022,50(20):11738
We describe a purified biochemical system to produce monoclonal antibodies (Abs) in vitro using activation-induced deoxycytidine deaminase (AID) and DNA polymerase η (Polη) to diversify immunoglobulin variable gene (IgV) libraries within a phage display format. AID and Polη function during B-cell affinity maturation by catalyzing somatic hypermutation (SHM) of immunoglobulin variable genes (IgV) to generate high-affinity Abs. The IgV mutational motif specificities observed in vivo are conserved in vitro. IgV mutations occurred in antibody complementary determining regions (CDRs) and less frequently in framework (FW) regions. A unique feature of our system is the use of AID and Polη to perform repetitive affinity maturation on libraries reconstructed from a preceding selection step. We have obtained scFv Abs against human glucagon-like peptide-1 receptor (GLP-1R), a target in the treatment of type 2 diabetes, and VHH nanobodies targeting Fatty Acid Amide Hydrolase (FAAH), involved in chronic pain, and artemin, a neurotropic factor that regulates cold pain. A round of in vitro affinity maturation typically resulted in a 2- to 4-fold enhancement in Ab-Ag binding, demonstrating the utility of the system. We tested one of the affinity matured nanobodies and found that it reduced injury-induced cold pain in a mouse model. 相似文献
56.
Toshihiro Hamajima Fumie Takahashi Koji Kato Koichiro Mukoyoshi Kousei Yoshihara Susumu Yamaki Yukihito Sugano Ayako Moritomo Kaoru Yamagami Koji Yokoo Hidehiko Fukahori 《Bioorganic & medicinal chemistry》2018,26(9):2410-2419
Phosphatidylinositol-3-kinase (PI3K)δ inhibition is one of the most attractive approaches to the treatment of autoimmune diseases and leukocyte malignancies. Through the exploration of pyrazolopyridine derivatives as potential PI3Kδ inhibitors, compound 12a was identified as a potent PI3Kδ inhibitor but suffered from poor oral exposure in mice. With a modified amide linkage group, compound 15a was developed as an orally available PI3Kδ inhibitor with reduced selectivity against other PI3Ks. To improve the trade-off between selectivity and PK profile, structure–activity relationship (SAR) studies of terminal substituents on the pyrolidine ring were conducted. As a result, we developed potent PI3Kδ inhibitors with good oral availability. In particular, the representative compound 15j showed excellent selectivity for PI3Kδ over other PI3Ks with good oral exposure in mice. 相似文献
57.
Toshihiro Hamajima Fumie Takahashi Koji Kato Yukihito Sugano Susumu Yamaki Ayako Moritomo Satoshi Kubo Koji Nakamura Kaoru Yamagami Nozomu Hamakawa Koji Yokoo Hidehiko Fukahori 《Bioorganic & medicinal chemistry》2018,26(14):3917-3924
Chemical optimization of pyrazolopyridine 1, focused on cellular potency, isoform selectivity and microsomal stability, led to the discovery of the potent, selective and orally available PI3Kδ inhibitor 5d. On the basis of its desirable potency, selectivity and pharmacokinetic profiles, 5d was tested in the trinitrophenylated aminoethylcarboxymethyl-Ficoll (TNP-Ficoll)-induced antibody production model, and showed higher antibody inhibition than a 4-fold oral dose of the starting compound 1. These excellent results suggest that 5d is a potential candidate for further studies in the treatment of autoimmune diseases and leukocyte malignancies. 相似文献
58.
Sugar uptake into strawberry fruit is stimulated by abscisic acid and indoleacetic acid 总被引:5,自引:0,他引:5
Changes in sugar uptake into strawberry fruits with maturation and the hormonal effect on uptake mechanisms, though important to fruit development, are not known. Therefore, the kinetics of sugar uptake into strawberry ( Fragaria x ananassa Duch cv. Nyoho) fruit tissue and the effects of abscisic acid (ABA) and indoleacetic acid (LAA) on the mechanism of uptake were investigated at 25 and 35 days after pollination (DAP). Uptake of 14 C-sugar was measured over the concentration range of 2 to 30 m M. Uptake kinetics showed a biphasic response to increasing external concentration of 14 C-sugars, and indicated the presence of P -chlorormercuribenzenesulfonic acid (PCMBS)-sensitive and PCMBS-insensitive uptake. The Km value for each sugar was in the range of 10 to 20 m M. Stage of development had no effect on Km. but Vmax for glucose decreased with maturation. Further, sucrose was not taken up through a PC-MBS-sensitive transport at 35 DAP. ABA, especially 10 μ M , at 25 DAP stimulated uptake of all sugars, mostly through enhanced PCMBS-insensitive uptake but not PC-MBS-sensitive uptake. In contrast to ABA, stimulation of sugar uptake by IAA was most effective at 1 μ M . The PCMBS-insensitive uptake of each sugar was also stimulated by IAA. Further, the PCMBS-sensitive uptake of glucose was enhanced. The developmental change of PCMBS-sensitive sugar uptake and the effect of ABA and IAA on uptake mechanism in this study are considered to be important in influencing the development and enlargement of fruits. 相似文献
59.
A Slomiany S Sano M Grabska K Yamaki B L Slomiany 《Journal of physiology and pharmacology》2004,55(4):837-860
Homeostatic cell physiology is preserved through the fidelity of the cell membranes restitution. The task is accomplished through the assembly of the precisely duplicated segments of the cell membranes, and transport to the site of their function. Here we examined the mechanism that initiates and directs the restitution of the intra- and extracellular membranes of gastric mucosal cell. The homeostatic restitution of gastrointestinal epithelial cell membrane components was investigated by studying the lipidomic processes in endoplasmic reticulum (ER) and Golgi. The biomembrane lipid synthesis during the formation of transport vesicles in the systems containing isolated organelle and the cell-specific cytosol (Cyt) from rat gastric mucosal epithelial cells was assessed. The results revealed that lipids of ER transport vesicle and the transmembrane and intravesicular cargo are delivered en bloc to the point of destination. En bloc delivery of proteins, incorporated into predetermined in ER lipid environment, ensures fidelity of the membrane modification in Golgi and the restitution of the lipid and protein elements that are consistent with the organelle and the cell function. The mechanism that maintains apical membrane restitution is mediated through the synthesis of membrane segments containing ceramide (Cer). The Cer-containing membranes and protein cargo are further specialized in Golgi. The portion of the vesicles destined for apical membrane renewal contains glycosphingolipids and phosphatidylinositol 3-phosphate. The vesicles containing phosphatidylinositol 4-phosphate are directed to endosomes. Our findings revealed that the preservation of the physiological equilibrium in cell structure and function is attributed to (1) a complete membrane segment synthesis in ER, (2) its transport in the form of ER-transport vesicle to Golgi, (3) the membrane components-defined maturation of lipids and proteins in Golgi, and (4) en bloc transfer of the new segment of the membrane to the cell apical membrane or intracellular organelle. 相似文献
60.
Yoichiro Harada Chengcheng Huang Satoshi Yamaki Naoshi Dohmae Tadashi Suzuki 《The Journal of biological chemistry》2016,291(15):8048-8058
Phosphorylated oligosaccharides (POSs) are produced by the degradation of dolichol-linked oligosaccharides (DLOs) by an unclarified mechanism in mammalian cells. Although POSs are exclusively found in the cytosol, their intracellular fates remain unclear. Our findings indicate that POSs are catabolized via a non-lysosomal glycan degradation pathway that involves a cytosolic endo-β-N-acetylglucosaminidase (ENGase). Quantitative and structural analyses of POSs revealed that ablation of the ENGase results in the significant accumulation of POSs with a hexasaccharide structure composed of Manα1,2Manα1,3(Manα1,6)Manβ1,4GlcNAcβ1,4GlcNAc. In vitro ENGase assays revealed that the presence of an α1,2-linked mannose residue facilitates the hydrolysis of POSs by the ENGase. Liquid chromatography-mass spectrometric analyses and fluorescent labeling experiments show that such POSs contain one phosphate group at the reducing end. These results indicate that ENGase efficiently hydrolyzes POSs that are larger than Man4GlcNAc2-P, generating GlcNAc-1-P and neutral Gn1-type free oligosaccharides. These results provide insight into important aspects of the generation and degradation of POSs. 相似文献