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991.
The cytoplasmic tail of invariant chain regulates endosome fusion and morphology 总被引:3,自引:0,他引:3
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Nordeng TW Gregers TF Kongsvik TL Méresse S Gorvel JP Jourdan F Motta A Bakke O 《Molecular biology of the cell》2002,13(6):1846-1856
The major histocompatibility complex class II associated invariant chain (Ii) has been shown to inhibit endocytic transport and to increase the size of endosomes. We have recently found that this property has a significant impact on antigen processing and presentation. Here, we show in a cell-free endosome fusion assay that expression of Ii can increase fusion after phosphatidylinositol 3-kinase activity is blocked by wortmannin. In live cells wortmannin was also not able to block formation of the Ii-induced enlarged endosomes. The effects of Ii on endosomal transport and morphology depend on elements within the cytoplasmic tail. Data from mutagenesis analysis and nuclear magnetic resonance-based structure calculations of the Ii cytoplasmic tail demonstrate that free negative charges that are not involved in internal salt bridges are essential for both interactions between the tails and for the formation of enlarged endosomes. This correlation indicates that it is interactions between the Ii cytoplasmic tails that are involved in endosome fusion. The combined data from live cells, cell-free assays, and molecular dynamic simulations suggest that Ii molecules on different vesicles can promote endosome docking and fusion and thereby control endosomal traffic of membrane proteins and endosomal content. 相似文献
992.
Gizem Kayki Mutlu Ebru Arioglu Inan Irem Karaomerlioglu V. Melih Altan Nilgun Yersal Petek Korkusuz Marcella Rocchetti Antonio Zaza 《Molecular and cellular biochemistry》2018,444(1-2):149-160
Alpha-synuclein (α-synuclein) aggregation and impairment of the Ubiquitin proteasome system (UPS) are implicated in Parkinson’s disease (PD) pathogenesis. While zinc (Zn) induces dopaminergic neurodegeneration resulting in PD phenotype, its effect on protein aggregation and UPS has not yet been deciphered. The current study investigated the role of α-synuclein aggregation and UPS in Zn-induced Parkinsonism. Additionally, levodopa (l-Dopa) response was assessed in Zn-induced Parkinsonian model to establish its closeness with idiopathic PD. Male Wistar rats were treated with zinc sulfate (Zn; 20 mg/kg; i.p.) twice weekly for 12 weeks along with respective controls. In few subsets, animals were subsequently treated with l-Dopa for 21 consecutive days following Zn exposure. A significant increase in total and free Zn content was observed in the substantia nigra of the brain of exposed groups. Zn treatment caused neurobehavioral anomalies, striatal dopamine decline, and dopaminergic neuronal cell loss accompanied with a marked increase in α-synuclein expression/aggregation and Ubiquitin-conjugated protein levels in the exposed groups. Zn exposure substantially reduced UPS-associated trypsin-like, chymotrypsin-like, and caspase-like activities along with the expression of SUG1 and β-5 subunits of UPS in the nigrostriatal tissues of exposed groups. l-Dopa treatment rescued from Zn-induced neurobehavioral deficits and restored dopamine levels towards normalcy; however, Zn-induced dopaminergic neuronal loss, reduction in tyrosine hydroxylase expression, and increase in oxidative stress were unaffected. The results suggest that Zn caused UPS impairment, resulting in α-synuclein aggregation subsequently leading to dopaminergic neurodegeneration, and that Zn-induced Parkinsonism exhibited positive l-Dopa response similar to sporadic PD. 相似文献
993.
Frequency of consanguineous marriages among parents and grandparents of Down patients 总被引:2,自引:1,他引:1
Marcella Devoto Letizia Prosperi Franca Dagna Bricarelli D. A. Coviello G. Croci L. Zelante Giovanna Ferranti R. Tenconi Chiara Stomeo G. Romeo 《Human genetics》1985,70(3):256-258
Summary The existence of a rare autosomal gene which in the homozygous state would cause mitotic nondisjunction in the Down zygote has been hypothesized in the past by Alfi et al. (1980). This hypothesis can be supported or contradicted by the study of the frequency of consanguineous marriages among parents of affected children. Our study on 242 children affected with Down syndrome does not show any increase in the frequency of consanguineous marriages among their parents with respect to the general population, and therefore does not support the hypothesis of an autosomal gene controlling mitotic nondisjunction. Our data do not show any increase in the frequency of consanguineaous marriages even among paternal and maternal grandparents of the affected children, thus not supporting the other possible explanation of an autosomal recessive condition in one of the patient's parents which would cause meiotic nondisjunction. 相似文献
994.
The interactions of theω-amino acid ligandsε-aminocaproic acid andp-benzylaminesulphonic acid with the isolated kringle 4 domain from human plasminogen have been investigated by1H-nuclear magnetic resonance spectroscopy at 300 and 600 MHz. Overall, the data indicate that binding either ligand does not
cause the kringle to undergo significant conformational changes. When p-benzylaminesulphonic acid is in excess relative to
the kringles, progressive exchange-broadening and high field chemical shifts are observed for the proton resonances of the
ligand. The largest effect is seen at the amino end of the molecule, which indicates that the — NH
3
+
group of the ligand penetrates deeper into the binding site than does the — SO
3
-
. Ligand-binding causes signals from the ring-current shifted Leu46 CH
3
δ
.δ groups and from a number of aromatic side-chains to shift. Depending on the ligand, the latter include Tyr-II (Tyr50), Tyr-V (an immobile ring), His-II and His-III imidazole groups and the three Trp indole groups present in kringle 4. In
particular,p-benzylaminesulphonic acid-binding induces large high field shifts on the Trp-II H6 triplet and the Trp-III (Trp72) H2 singlet. On the other hand,ε-aminocaproic acid bound to kringle 4 exhibits large chemical shifts of its CH2 proton resonances, which indicates that the lysine-binding site is rich in aromatic side chains.
Overhauser experiments centered on thep-benzylaminesulphonic acid H2,6 and H3,5 aromatic transitions as well as on the shifted Trp-II and Trp-III signals reveal
efficient cross-relaxation between these two indole side chains and thep-benzylaminesulphonic acid ring. These experiments also show that the side chains from Phe64, Tyr-II (Tyr50), Tyr-IV, and His-II (His31) interact with the ligand. In combination with reported chemical modification experiments that show requirement of Asp57, Arg71 and Trp72 integrity for ligand-binding, our study underscores the relevance of the Cys51-Cys75 loop in defining the kringles’ lysine-binding site. Furthermore, the Cys22-Cys63 loop is folded so as to place His31, His33, Tyr41 and Leu46 in proximity to the binding site. The involvement of residues within the Cys51-Cys75 loop in ligand-binding suggests that Trp-II and Tyr-IV may correspond to Trp62 and Tyr74, respectively. As shown by Overhauser experiments, these two residues are in close contact with each other. From these studies
and from the shielding and deshielding effects caused byp-benzylaminesulphonic acid, we suggest that the ligand is sandwiched between the indole rings of Trp-II and Trp-III, which form part of the hydrophobic binding site. 相似文献
995.
996.
Segregation of genes transferred to one plant cell from two separate Agrobacterium strains 总被引:22,自引:0,他引:22
Agrobacterium tumefaciens and Agrobacterium rhizogenes are soil bacteria which transfer DNA (T-DNA) to plant cells. Two Agrobacterium strains, each with a different T-DNA, can infect plants and give rise to transformed tissue which has markers from both T-DNAs. Although marker genes from both T-DNAs are in the tissue, definitive proof that the tissue is a cellular clone and that both T-DNAs are in a single cell is necessary to demonstrate cotransformation. We have transferred two distinguishable T-DNAs, carried on binary vectors in separate Agrobacterium rhizogenes strains, into tomato cells and have recovered hairy roots which received both T-DNAs. Continued expression of marker genes from each T-DNA in hairy roots propagated from individual root tips indicated that both T-DNAs were present in a single meristem. Also, we have transferred the two different T-DNAs, carried on identical binary vector plasmids in separate Agrobacterium tumefaciens strains, into tobacco cells and recovered plants which received both T-DNAs. Transformed plants with marker genes from each T-DNA were outcrossed to wild-type tobacco plants. Distribution of the markers in the F1 generation from three cotransformed plants of independent origin showed that both T-DNAs in the plants must have been present in the same cell and that the T-DNAs were genetically unlinked. Cotransformation of plant cells with T-DNAs from two bacterial strains and subsequent segregation of the transferred genes should be useful for altering the genetic content of higher plants. 相似文献
997.
Linkage disequilibrium between cystic fibrosis and linked DNA polymorphisms in Italian families: A collaborative study 总被引:14,自引:9,他引:5
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Xavier Estivill Martin Farrall Robert Williamson Maurizio Ferrari Manuela Seia Anna Maria Giunta Giuseppe Novelli Lucia Potenza Bruno Dallapicolla Graziella Borgo Paolo Gasparini Pier F. Pignatti Laura De Benedetti Emilia Vitale Marcella Devoto Giovanni Romeo 《American journal of human genetics》1988,43(1):23-28
The locus D7S23 includes a CpG-enriched methylation-free island that maps midway between the markers J3.11 and met and is genetically very close to the mutation causing cystic fibrosis (CF). We have studied the linkage disequilibrium between four polymorphic markers from this locus (KM.19, CS.7, XV-2c, and PT-3) and the CF mutation (CF) in 127 Italian families. Strong linkage disequilibrium is found between KM.19, CS.7, and CF, and weaker but significant disequilibrium is found between XV-2c, PT-3, and CF. The disequilibrium between markers and CF for the Italian population provides additional information on the origin and homogeneity of the CF defect. This panel of probes is sufficiently informative to permit accurate prenatal diagnosis of CF in most families with an affected person, and the disequilibrium also allows indirect carrier detection/exclusion in some cases. 相似文献
998.
Zenildo Santos Silva Junior Lucas Andreo Dias dos Santos Marcela Leticia Leal Gonçalves Juliana Maria Altavista Sagretti Gallo Tamiris da Silva Lara Jansiski Motta Elaine Marcílio Santos Anna Carolina Ratto Tempestini Horliana Kristianne Porta Santos Fernandes Raquel Agnelli Mesquita-Ferrari Sandra Kalil Bussadori 《Journal of biophotonics》2023,16(3):e202200259
999.
Herbaria are potentially important repositories of living seeds that could be useful for recovery of rare plant species. To examine this capacity, we tested seed germination of rare milkweed (Asclepias) and milkvetch (Astragalus) species representing different collection dates and different herbaria. These groups have contrasting seed characteristics, with greater potential for longevity in the nonpermeable hard-coated milkvetch seeds. Twelve-year-old Asclepias lanuginosa seeds failed to germinate. However, we achieved 45% germination from three-year-old Asclepias meadii seeds, but germination dropped to 0% after ages of four to five years. Astragalus neglectus seeds germinated from 97-, 48-, and 28-year-old herbarium specimens, and Astragalus tennesseensis seeds germinated from a four-year-old collection. Seedlings produced from these experiments were incorporated into ex situ garden populations for recovery or restoration of rare species populations. Different herbarium pest control techniques may have significant bearing on the viability of seeds stored on herbarium specimens. Microwaving can cause precipitous loss of seed viability, while deep-freezing appears to allow some seeds to remain viable. Potentially live seeds of rare species should be stored under conditions that enhance their long-term viability. 相似文献
1000.
Renata Dalmaschio Daltoé Leticia Batista Azevedo Rangel Maicon Delarmelina Klesia Pirola Madeira Marcella Leite Porto Silvana Santos Meirelles Isabella dos Santos Guimarães Éclair Venturini Filho Alan Reinke Pereira Rafael de Queiroz Ferreira Gabriel Fernandes Souza dos Santos Izabela de França Schaffel José Walkimar de Mesquita Carneiro Artur M. S. Silva Sandro José Greco 《化学与生物多样性》2023,20(2):e202200807
In this study, eight naphthoquinone derivatives were synthesized in yields ranging from 52 to 96% using easy, fast, and low-cost methodologies. All naphthoquinone derivatives were screened for their in vitro anti-proliferative activities against OVCA A2780 cancer cell lines. Amongst all analysed compounds, derivatives 3 – 5 presented the most prominent cytotoxic potential. Naphthoquinones 3 and 4 , bearing sulfur-containing groups, were identified as having high potential for ROS production, in particular the superoxide anion. Furthermore, 3 and 4 compounds caused a decrease in the cell population in G0/G1 and induced more than 90% of the cell population to apoptosis. Compound 5 did not act in any of these processes. Finally, compounds 3 – 5 were tested for their inhibitory ability against PI3K and MAPK. Compounds 3 and 4 do not inhibit the PI3K enzyme. On the other hand, the naphthoquinone-polyphenol 5 was only able to inhibit the percentage of cells expressing pERK. 相似文献