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81.
Margery L Evans Jens C Schmidt Marianne Ilbert Shannon M Doyle Shu Quan James CA Bardwell Ursula Jakob Sue Wickner Matthew R Chapman 《朊病毒》2011,5(4):323-334
Amyloid formation is an ordered aggregation process, where β-sheet rich polymers are assembled from unstructured or partially folded monomers. We examined how two Escherichia coli cytosolic chaperones, DnaK and Hsp33, and a more recently characterized periplasmic chaperone, Spy, modulate the aggregation of a functional amyloid protein, CsgA. We found that DnaK, the Hsp70 homolog in E. coli, and Hsp33, a redox-regulated holdase, potently inhibited CsgA amyloidogenesis. The Hsp33 anti-amyloidogenesis activity was oxidation dependent, as oxidized Hsp33 was significantly more efficient than reduced Hsp33 at preventing CsgA aggregation. When soluble CsgA was seeded with preformed amyloid fibers, neither Hsp33 nor DnaK were able to efficiently prevent soluble CsgA from adopting the amyloid conformation. Moreover, both DnaK and Hsp33 increased the time that CsgA was reactive with the amyloid oligomer conformation-specific A11 antibody. Since CsgA must also pass through the periplasm during secretion, we assessed the ability of the periplasmic chaperone Spy to inhibit CsgA polymerization. Like DnaK and Hsp33, Spy also inhibited CsgA polymerization in vitro. Overexpression of Spy resulted in increased chaperone activity in periplasmic extracts and in reduced curli biogenesis in vivo. We propose that DnaK, Hsp33 and Spy exert their effects during the nucleation stages of CsgA fibrillation. Thus, both housekeeping and stress induced cytosolic and periplasmic chaperones may be involved in discouraging premature CsgA interactions during curli biogenesis.Key words: chaperone, curli, functional amyloid, CsgA, DnaK, Hsp33, Spy 相似文献
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84.
CA Lei- CHEN Run-Zheng- YIN Zhi-Jian- ZHANG Guo-Xue- CHEN Wen-Hong- SHUI Yu-Min 《Plant Diversity》2015,37(6):733-736
A new species of Gesneriaceae from Honghe County, Southeastern Yunnan, China, Tremacron hongheense WH. Chen & YM. Shui, is described and illustrated. The new species is similar to Tremacron forrestii Craib, but differs by its leaf blade adaxially sparsely long setose (vs. densely white appressed pubescent and sparsely rusty brown villous), corolla tube outside short white glandular (vs. nearly glabrous), corolla lobes red and thickening at apex, especially adaxial lip (vs. yellow and not thickening), stamens 16-18cm long (vs. 04-12cm long), staminode 05-14cm long (vs. 02-04cm long). 相似文献
85.
Grasslands are one of the most widespread landscapes worldwide, covering approximately one-fifth of the world’s land surface, where grazing is a common practice. How carbon storage responds to grazing in steppes remains poorly understood. We quantified the effects of grazing on community composition and species diversity, and carbon storage in two typical grasslands of northeastern China, one in Horqin and the other one in Hulunbeier. In both grasslands, grazing did not influence plant species diversity. However, it substantially decreased aboveground carbon by 31% and 54% in Horqin and Hulunbeier, respectively. Fenced and grazing treatments showed a similar belowground carbon at both locations. The predominant carbon pool in the study grassland ecosystem was found in the upper 100 cm soil depth, from 98.2 to 99.1% of the total carbon storage. There were no significant effects of grazing on soil carbon neither in the whole profile nor in the uppermost 20 cm soil depth in the two study grasslands. Studies on the effects of varying rangeland management, such as region disparity and grazing systems, may have important consequences on species diversity and carbon partitioning, and thus on rangeland stability and ecosystem functioning. 相似文献
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Craig J Smith Hedley CA Emsley Carole M Gavin Rachel F Georgiou Andy Vail Elisa M Barberan Gregory J del Zoppo John M Hallenbeck Nancy J Rothwell Stephen J Hopkins Pippa J Tyrrell 《BMC neurology》2004,4(1):1-8
Background
Cerebral ischaemia initiates an inflammatory response in the brain and periphery. We assessed the relationship between peak values of plasma interleukin-6 (IL-6) in the first week after ischaemic stroke, with measures of stroke severity and outcome.Methods
Thirty-seven patients with ischaemic stroke were prospectively recruited. Plasma IL-6, and other markers of peripheral inflammation, were measured at pre-determined timepoints in the first week after stroke onset. Primary analyses were the association between peak plasma IL-6 concentration with both modified Rankin score (mRS) at 3 months and computed tomography (CT) brain infarct volume.Results
Peak plasma IL-6 concentration correlated significantly (p < 0.001) with CT brain infarct volume (r = 0.75) and mRS at 3 months (r = 0.72). It correlated similarly with clinical outcome at 12 months or stroke severity. Strong associations were also noted between either peak plasma C-reactive protein (CRP) concentration or white blood cell (WBC) count, and all outcome measures.Conclusions
These data provide evidence that the magnitude of the peripheral inflammatory response is related to the severity of acute ischaemic stroke, and clinical outcome. 相似文献88.
cis-acting sequences required for coronavirus infectious bronchitis virus defective-RNA replication and packaging 总被引:6,自引:0,他引:6 下载免费PDF全文
Dalton K Casais R Shaw K Stirrups K Evans S Britton P Brown TD Cavanagh D 《Journal of virology》2001,75(1):125-133
The parts of the RNA genome of infectious bronchitis virus (IBV) required for replication and packaging of the RNA were investigated using deletion mutagenesis of a defective RNA (D-RNA) CD-61 (6.1 kb) containing a chloramphenicol acetyltransferase reporter gene. A D-RNA with the first 544, but not as few as 338, nucleotides (nt) of the 5' terminus was replicated; the 5' untranslated region (UTR) comprises 528 nt. Region I of the 3' UTR, adjacent to the nucleocapsid protein gene, comprised 212 nt and could be removed without impairment of replication or packaging of D-RNAs. A D-RNA with the final 338 nt, including the 293 nt in the highly conserved region II of the 3' UTR, was replicated. Thus, the 5'-terminal 544 nt and 3'-terminal 338 nt contained the necessary signals for RNA replication. Phylogenetic analysis of 19 strains of IBV and 3 strains of turkey coronavirus predicted a conserved stem-loop structure at the 5' end of region II of the 3' UTR. Removal of the predicted stem-loop structure abolished replication of the D-RNAs. D-RNAs in which replicase gene 1b-derived sequences had been removed or replaced with all the downstream genes were replicated well but were rescued poorly, suggesting inefficient packaging. However, no specific part of the 1b gene was required for efficient packaging. 相似文献
89.
Germana B Rona Natalia P Almeida Gilson C Santos Jr Tatiana KS Fidalgo Fabio CL Almeida Elis CA Eleutherio Anderson S Pinheiro 《Journal of cellular biochemistry》2019,120(4):5377-5385
NSD3s, the proline-tryptophan-tryptophan-proline (PWWP) domain-containing, short isoform of the human oncoprotein NSD3, displays high transforming properties. Overexpression of human NSD3s or the yeast protein Pdp3 in Saccharomyces cerevisiae induces similar metabolic changes, including increased growth rate and sensitivity to oxidative stress, accompanied by decreased oxygen consumption. Here, we set out to elucidate the biochemical pathways leading to the observed metabolic phenotype by analyzing the alterations in yeast metabolome in response to NSD3s or Pdp3 overexpression using 1H nuclear magnetic resonance (NMR) metabolomics. We observed an increase in aspartate and alanine, together with a decrease in arginine levels, on overexpression of NSD3s or Pdp3, suggesting an increase in the rate of glutaminolysis. In addition, certain metabolites, including glutamate, valine, and phosphocholine were either NSD3s or Pdp3 specific, indicating that additional metabolic pathways are adapted in a protein-dependent manner. The observation that certain metabolic pathways are differentially regulated by NSD3s and Pdp3 suggests that, despite the structural similarity between their PWWP domains, the two proteins act by unique mechanisms and may recruit different downstream signaling complexes. This study establishes for the first time a functional link between the human oncoprotein NSD3s and cancer metabolic reprogramming. 相似文献
90.
Natália Spitz Francisco CA Mello Natalia Motta Araujo 《Memórias do Instituto Oswaldo Cruz》2015,110(1):151-153
The Brazilian Amazon Region is a highly endemic area for hepatitis B virus (HBV).
However, little is known regarding the genetic variability of the strains circulating
in this geographical region. Here, we describe the first full-length genomes of HBV
isolated in the Brazilian Amazon Region; these genomes are also the first complete
HBV subgenotype D3 genomes reported for Brazil. The genomes of the five Brazilian
isolates were all 3,182 base pairs in length and the isolates were classified as
belonging to subgenotype D3, subtypes ayw2 (n = 3) and ayw3 (n = 2). Phylogenetic
analysis suggested that the Brazilian sequences are not likely to be closely related
to European D3 sequences. Such results will contribute to further epidemiological and
evolutionary studies of HBV. 相似文献