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51.
Claire J. Sarell Theodoros K. Karamanos Simon J. White David H. J. Bunka Arnout P. Kalverda Gary S. Thompson Amy M. Barker Peter G. Stockley Sheena E. Radford 《The Journal of biological chemistry》2014,289(39):26859-26871
Although amyloid fibrils assembled in vitro commonly involve a single protein, fibrils formed in vivo can contain multiple protein sequences. The amyloidogenic protein human β2-microglobulin (hβ2m) can co-polymerize with its N-terminally truncated variant (ΔN6) in vitro to form hetero-polymeric fibrils that differ from their homo-polymeric counterparts. Discrimination between the different assembly precursors, for example by binding of a biomolecule to one species in a mixture of conformers, offers an opportunity to alter the course of co-assembly and the properties of the fibrils formed. Here, using hβ2m and its amyloidogenic counterpart, ΔΝ6, we describe selection of a 2′F-modified RNA aptamer able to distinguish between these very similar proteins. SELEX with a N30 RNA pool yielded an aptamer (B6) that binds hβ2m with an EC50 of ∼200 nm. NMR spectroscopy was used to assign the 1H-15N HSQC spectrum of the B6-hβ2m complex, revealing that the aptamer binds to the face of hβ2m containing the A, B, E, and D β-strands. In contrast, binding of B6 to ΔN6 is weak and less specific. Kinetic analysis of the effect of B6 on co-polymerization of hβ2m and ΔN6 revealed that the aptamer alters the kinetics of co-polymerization of the two proteins. The results reveal the potential of RNA aptamers as tools for elucidating the mechanisms of co-assembly in amyloid formation and as reagents able to discriminate between very similar protein conformers with different amyloid propensity. 相似文献
52.
Soultanakis HN Mandaloufas MF Platanou TI 《Journal of strength and conditioning research / National Strength & Conditioning Association》2012,26(1):131-137
The purpose of this study was to investigate the impact of 4 weeks of high-intensity vs. high-volume swim training on lactate threshold (LT) characteristics and performance. Thirteen untrained swimmers with a mean age of 19.0 ± 0.5 undertook an incremental swimming test before and after 4 weeks of training for the determination of LT. Performance was evaluated by a 50-m maximum freestyle test. The swimmers were assigned to 1 of each of 2 training groups. The high-intensity group (n = 6) focused on sprint training (SP) and swam a total of 1,808 ± 210 m. The high-volume group (n = 7) followed the same program as the SP group but swam an additional 1,100 m (38% more) of endurance swimming (SP + End). A training effect was evident in both groups as seen by the similar improvements in sprint performance of the 50-m maximum time (p < 0.01), peak velocity increases and the lower value of lactate at the individual LTs (p < 0.01). Lactate threshold velocity improved only in the SP + End group from 1.20 ± 0.12 m·s(-1) pretraining to 1.32 ± 0.12 m·s(-1) posttraining (p = 0.77, effect size = 1, p < 0.01), expressed by the rightward shifts of the individual lactate-velocity curves, indicating an improvement in the aerobic capacity. Peak lactate and lactate concentrations at LT did not significantly change. In conclusion, this study was able to demonstrate that 4 weeks of either high-intensity or high-volume training was able to demonstrate similar improvements in swimming performance. In the case of lack of significant changes in lactate profiling in response to high-intensity training, we could suggest a dissociation between the 2. 相似文献
53.
Theodoros Goulas Athanasios Goulas George Tzortzis Glenn R. Gibson 《Applied microbiology and biotechnology》2009,82(3):471-477
A genomic library of Bifidobacterium bifidum (NCIMB 41171) DNA was constructed in Escherichia coli RA11r (melA−B+) and one α-galactosidase encoding gene was isolated. Conceptual translation combined with insertional mutagenesis analysis
indicated an open reading frame (ORF) of 759 amino acid (aa) residues encoding an α-galactosidase (named as MelA) of 82.8 kDa.
Partial purification and characterisation showed that the enzyme had an apparent native molecular mass of ≈243 kDa and a subunit
size of ≈85 kDa. The enzyme belongs to glycosyl hydrolases 36 family with high aa sequence similarities (≈73%) to other known
α-galactosidases of bifidobacterial origin. Under optimum pH conditions for activity (pH 6.0) and high melibiose concentration
(40% w/v), the enzyme was able to form oligosaccharides with degree of polymerisation (DP) ≥3 at higher concentration than DP = 2,
with a total yield of 20.5% (w/w). 相似文献
54.
Sophie A. Lee Theodoros Economou Rafael de Castro Cato Christovam Barcellos Rachel Lowe 《PLoS neglected tropical diseases》2021,15(12)
Dengue is hyperendemic in Brazil, with outbreaks affecting all regions. Previous studies identified geographical barriers to dengue transmission in Brazil, beyond which certain areas, such as South Brazil and the Amazon rainforest, were relatively protected from outbreaks. Recent data shows these barriers are being eroded. In this study, we explore the drivers of this expansion and identify the current limits to the dengue transmission zone. We used a spatio-temporal additive model to explore the associations between dengue outbreaks and temperature suitability, urbanisation, and connectivity to the Brazilian urban network. The model was applied to a binary outbreak indicator, assuming the official threshold value of 300 cases per 100,000 residents, for Brazil’s municipalities between 2001 and 2020. We found a nonlinear relationship between higher levels of connectivity to the Brazilian urban network and the odds of an outbreak, with lower odds in metropoles compared to regional capitals. The number of months per year with suitable temperature conditions for Aedes mosquitoes was positively associated with the dengue outbreak occurrence. Temperature suitability explained most interannual and spatial variation in South Brazil, confirming this geographical barrier is influenced by lower seasonal temperatures. Municipalities that had experienced an outbreak previously had double the odds of subsequent outbreaks. We identified geographical barriers to dengue transmission in South Brazil, western Amazon, and along the northern coast of Brazil. Although a southern barrier still exists, it has shifted south, and the Amazon no longer has a clear boundary. Few areas of Brazil remain protected from dengue outbreaks. Communities living on the edge of previous barriers are particularly susceptible to future outbreaks as they lack immunity. Control strategies should target regions at risk of future outbreaks as well as those currently within the dengue transmission zone. 相似文献
55.
Kolettas E Skoufos I Kontargiris E Markopoulou S Tzavaras T Gonos ES 《Archives of biochemistry and biophysics》2006,445(1):184-195
The role of clusterin/apolipoprotein J (Clu/ApoJ) and Bcl-2 on C(2)-ceramide-induced apoptosis of embryonic human diploid fibroblasts, MRC-5 and immortalized adult skin keratinocytes, HaCaT was investigated. C(2)-ceramide-induced apoptosis of HaCaT in a time- and dose-dependent manner, while in MRC-5 only at higher concentrations. There was a dose-dependent accumulation of Clu/ApoJ and downregulation of Bcl-2 which correlated with C(2)-ceramide-induced apoptosis of MRC-5. While overexpression of Bcl-2 suppressed C(2)-ceramide-mediated apoptosis in both cell types, Clu/ApoJ failed to do so, accessed by morphological changes, DNA fragmentation and PARP cleavage. There was no change in the expression of endogenous p53 or p21(Waf1/Cip1) upon C(2)-ceramide treatment of MRC-5. However, mutant p53(143ala) increased the sensitivity of MRC-5 to C(2)-ceramide-induced apoptosis by markedly downregulating Bcl-2, pointing to a role for p53. These results suggested that whereas downregulation of Bcl-2 may be a crucial factor involved in C(2)-ceramide-induced apoptosis, accumulation of Clu/ApoJ may be a signal of stress response. Moreover, the ceramide-activated apoptotic pathway may be regulated by p53. 相似文献
56.
Lo Djaoui Adam Owen Matt Newton Pantelis Theodoros Nikolaidis Alexandre Dellal Karim Chamari 《Biology of sport / Institute of Sport》2022,39(2):307
The aim of the present study was to analyse the influence of congested periods of matches on the acceleration (Acc) and deceleration (Dec) profiles of elite soccer players. Twenty-three elite male professional soccer players participated in the study across 31 official matches. Assessed periods included: (i) congested periods (three to four days between games), and (ii) non-congested periods (more than four days between games). Physical activity during matches was recorded during games using a 10Hz global positioning system device, coupled with a 100 Hz accelerometer, and was analysed according to the periods. Maximal Acc- (73.2 ± 20.3 vs. 84.918.5 m), high Acc- (244.0 ± 49.5 vs. 267.0 ± 37.8 m), maximal Dec- (139.0 ± 44.8 vs. 152.039.3 m) and the total decelerating- distance (5132 ± 690 vs. 5245 ± 552 m) were lower in congested than in non-congested periods (p < 0.05, effect size 0.31–0.70). Neither a main effect of playing position nor a period*playing position interaction on Acc and Dec were observed (p > 0.05). It was concluded that Acc and Dec match activities were significantly affected during congested periods compared to non-congested highlighting a possible fatigue accumulation being responsible for the observed decrement in physical activity. Monitoring Acc and Dec metrics throughout particular periods of congested fixtures amongst professional soccer teams is advised and may be a way to assess physical and fatigue status. 相似文献
57.
58.
Theodoros Dantsis Caterina Douma Christina Giourga Aggeliki Loumou Eleni A. Polychronaki 《Ecological Indicators》2010,10(2):256-263
A large number of indicators have been developed, in order to assess agricultural sustainability. However, there is no unified theoretical basis for the creation of a scientifically substantiated system of indicators and especially for data collection, analysis, scale and final goal. This paper proposes a methodological approach to assess and to compare the sustainability level of agricultural plant production systems on regional scale combining the three pillars of sustainability environment, economy and society. The combination of 21 individual indicators expressed a unique indicator was realized using the Multiattribute Value Theory (MAVT). The proposed methodology was testified on two geographical regions in Greece, through an empirical study, utilizing questionnaires completed during interviews with farm managers. The questionnaire was designed to gather data on current agricultural practices applied in each particular region and was separated into three broad groups of questions concerning (a) crop management practices, (b) economic performance and (c) social characteristics of each farm. The results of our study demonstrate the overall status of the studied regions, regarding their level of agricultural sustainability. Finally, findings related to the acceptability of the proposed methodological framework were discussed. 相似文献
59.
60.
Stylianos Panopoulos Maria Tektonidou Alexandros A. Drosos Stamatis-Nick Liossis Theodoros Dimitroulas Alexandros Garyfallos Lazaros Sakkas Dimitrios Boumpas Paraskevi V. Voulgari Dimitrios Daoussis Konstantinos Thomas Georgios Georgiopoulos Georgios Vosvotekas Dimitrios Vassilopoulos Petros P. Sfikakis 《Arthritis research & therapy》2018,20(1):267