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91.
92.
Sykiotis GP Neumann S Georgopoulos NA Sgourou A Papachatzopoulou A Markou KB Kyriazopoulou V Paschke R Vagenakis AG Papavassiliou AG 《Biochemical and biophysical research communications》2003,301(4):1051-1056
In a toxic thyroid adenoma we identified a novel somatic mutation that constitutively activates the thyrotropin receptor (TSHR). Two heterozygous point mutations at adjacent nucleotides led to a substitution of alanine with asparagine at codon 593 (A593N) in the fifth transmembrane helix of TSHR. This somatic mutation resided on the same TSHR allele with the germline polymorphism D727E. The functional characteristics of the single TSHR mutants A593N and D727E and of the double mutant A593N/D727E were studied in transiently transfected COS-7 cells. The TSHR mutants A593N and A593N/D727E constitutively activated the cAMP cascade, whereas the D727E mutant did not differ from the wild-type TSHR. Surprisingly, the double mutant's specific constitutive activity was 2.3-fold lower than the A593N mutant. Thus, the polymorphism significantly ameliorates G(alphas) protein activation in the presence of the gain-of-function mutation A593N, although it is functionally inert in the context of the wild-type TSHR. 相似文献
93.
Gerasimos Malandrinos Maria Louloudi Cristiana A. Mitsopoulou Ian S. Butler Robert Bau N. Hadjiliadis 《Journal of biological inorganic chemistry》1998,3(5):437-448
The crystal structure of the 2-(α-hydroxethyl) thiamin pyrophosphate (LH2) was solved by X-ray diffraction. Crystallographic data: space group F2dd, a=7.922(4) Å, b=33.11(2) Å, c=36.232(10) Å, V=9503(9) Å3, z=16. Metal complexes of the general formula K2{[M(LH)Cl2]2} (M=Zn2+, Cd2+) were isolated from methanolic solutions and characterized by elemental analysis, IR, Raman, and 13C CP MAS NMR spectra. They were also characterized by 13C NMR, 31P NMR, 113Cd NMR, ES-MS, and 1H NMR ROESY spectra in D2O solutions. The data provide evidence for the bonding of the metals to the N(1′) atom of the pyrimidine ring and to the pyrophosphate group. The free ligand and the metal-coordinated ligand adopt the S conformation. Since thiamin cofactor, substrate, and metal ions are present in our system, the extracted results directly refer to thiamin catalysis and possible functional implications are correlated and discussed. 相似文献
94.
The problem of dynamically modeling a chemostat is addressed. Using the results of continuous culture experiments for the growth of a strain of Saccharomyces cerevisiae on a glucose-limited medium, a general approach to developing dynamic models is discussed. The approach to develop and verify the model involves three different types of experiments: steady-state, dynamic step response, and feedback identification. 相似文献
95.
96.
Christiane Weirauch Randall T. Schuh Gerasimos Cassis Ward C. Wheeler 《Cladistics : the international journal of the Willi Hennig Society》2019,35(1):67-105
Heteroptera, the true bugs, are part of the largest clade of non-holometabolous insects, the Hemiptera, and include > 42 000 described species in about 90 families. Despite progress in resolving phylogenetic relationships between and within infraorders since the first combined morphological and molecular analysis published in 1993 (29 taxa, 669 bp, 31 morphological characters), recent hypotheses have relied entirely on molecular data. Weakly supported nodes along the backbone of Heteroptera made these published phylogenies unsuitable for investigations into the evolution of habitats and lifestyles across true bugs. Here we present the first combined morphological and molecular analyses of Heteroptera since 1993, using 135 taxa in 60 families, 4018 aligned bp of ribosomal DNA and 81 morphological characters, and various analytical approaches. The sister-group relationship of the predominantly aquatic Nepomorpha with all remaining Heteroptera is supported in all analyses, and a clade formed by Enicocephalomorpha, Dipsocoromorpha and Gerromorpha in some. All analyses recover Leptopodomorpha + (Cimicomorpha + Pentatomomorpha), mostly with high support. Parsimony- and likelihood-based ancestral state reconstructions of habitats and lifestyles on the combined likelihood phylogeny provide new insights into the evolution of true bugs. The results indicate that aquatic and semi-aquatic true bugs invaded these habitats three times independently from terrestrial habitats in contrast to a recent hypothesis. They further suggest that the most recent common ancestor of Heteroptera was predacious, and that the two large predominantly phytophagous clades (Trichophora and Miroidea) are likely to have derived independently from predatory ancestors. We conclude that by combining morphological and molecular data and employing various analytical methods our analyses have converged on a relatively well-supported hypothesis of heteropteran infraordinal relationships that now requires further testing using phylogenomic and more extensive morphological datasets. 相似文献
97.
Gerasimos Anagnostopoulos Omar Motio Sijing Li Vincent Carbonnier Hui Chen Valentina Sica Sylvre Durand Mlanie Bourgin Fanny Aprahamian Nitharsshini Nirmalathasan Romain Donne Chantal Desdouets Marcelo Simon Sola Konstantina Kotta La Montgut Flavia Lambertucci Didier Surdez Grossetête Sandrine Olivier Delattre Maria Chiara Maiuri Jos Manuel Bravo-San Pedro Isabelle Martins Guido Kroemer 《Cell death & disease》2022,13(5)
98.
A procedure for the implementation of quality control for laboratorysorting and identification of invertebrate specimens collected in biodiversityresearch is described. The procedure is based on process control sampling, aconcept of statistical process control (SPC) used widely in the manufacturingand information technology industries, and adapted to suit the tasks andproducts of biodiversity sorting procedures. The major advantages of processcontrol over other quality control mechanisms are that it is more stringent, andcontinuous. Hence, errors are detected and corrected as they occur, avoidingproliferation in the data set. The procedure is also highly interactive,offering the technicians the opportunity to learn as they work. Protocols havebeen developed while sorting material collected as part of a study into theimpacts associated with invasion of a habitat (coastal heath) by an exotic weed(bitou bush – Chrysanthemoides monilifera) on thecentral coast of New South Wales, Australia. Major findings from the analysis ofmaterial processed include: that errors may have a variety of causes andsubsequent implications for data quality, levels of identification errors can besignificant even at higher taxonomic levels (e.g. sorting insects to order),initial training periods on their own are insufficient to ensure errorminimisation, and even with stringent protocols the ratio of technician tospecialist effort can be maintained at a level of around 5:1. The need forincorporating effective quality control procedures into invertebratebiodiversity data compilations is emphasised. 相似文献
99.
Zavitsanos K Nunes AM Malandrinos G Hadjiliadis N 《Journal of inorganic biochemistry》2011,105(1):102-110
In an attempt to investigate the role of histone H2B in Cu(II) induced toxicity and carcinogenesis, we synthesized the terminally blocked peptides H2B32-62 (SRKESYSVYVYKVLKQVH48PDTGISSKAMGIM) and Η2Β94-125 (IQTAVRLLLPGELAKH110AVSEGTKAVTKYTSS), mimicking the N-terminal histone-fold domain and C-terminal tail of histone H2B, respectively and studied their interaction with Cu(II) ions by means of potentiometric titrations and spectroscopic techniques (UV-visible, CD and EPR). Both peptides, H2B32-62 and H2B94-125, interacted efficiently with Cu(II) ions, forming several species from pH 4 to 11, with His48 and His110 serving as anchors for metal binding. In H2B32-62, the effective Cu(II) binding is emphasized by the formation of a soluble Cu(II)-H2B32-62 complex, unlike the unbound peptide that precipitated over pH 7.9. At physiological pH, both peptides form tetragonal 3N species with a {NIm, 2N−} coordination mode. At this pH, H2B32-62 presented the formation of coordination isomers, differentiated by the presence in one of them, of an axial coordination of the carboxylate group of Asp50. Copper binding with both H2B32-62 and H2B94-125 may induce a conformational change in the peptides' original structure. At physiological conditions, this effect may interfere with nucleosome's structure and dynamics, including the ubiquitination of Lys120 which is linked to gene silencing. 相似文献
100.
Stable performance of anaerobic digestion in the presence of a high concentration of propionic acid 总被引:6,自引:0,他引:6
Pullammanappallil PC Chynoweth DP Lyberatos G Svoronos SA 《Bioresource technology》2001,78(2):165-169
An automatically controlled, glucose-fed, anaerobic digester was deliberately inhibited by addition of phenol. To overcome the phenol inhibition the feed dilution rate was lowered in such a way that the methane yield from glucose was kept the same as that under normal conditions. The concentrations of acetic and butyric acids remained below 100 mg/l, however, propionic acid accumulated to 2,750 mg/l. Phenol apparently inhibited all tropic groups of organisms and it was shown that the propionic acid was formed from the metabolism of phenol. From the nature of the operating strategy, it was deduced that the digester continued to convert all the glucose that was supplied to methane showing that propionic acid accumulation did not inhibit conversion of glucose to methane. Therefore, propionic acid accumulation may be an effect and not a cause of inhibition of the anaerobic digestion process. 相似文献