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Progression of resting quiescent G(0) cells into early G(1) and transition across the restriction point are highly regulated processes. Mutation of proto-oncogenes and tumor suppressor genes regulating these transitions are targeted during oncogenesis. Recent work has underscored the importance of the G(0) to early G(1) transition and metabolism to neoplastic cells.  相似文献   
84.
Three bovid species are present at Dorn-Dürkheim 1. The overwhelmingly abundant species is a boselaphine, Miotragocerus sp., with smaller and less advanced teeth than Tragoportax amalthea from Pikermi, Greece. Miotragocerus was present in the latest middle Miocene and Vallesian of western and central Europe and survived into the Turolian. The other two bovid species remain enigmatic and of uncertain tribal affiliation. Each is represented by very few teeth, none of them associated. One species is larger and the other smaller than the Miotragocerus sp. Mesowear analysis of M2s and M3s was used to investigate the dietary regime of Miotragocerus sp. from Dorn-Dürkheim 1. Miotragocerus was found to be linked to extant browsing ungulates close to the transition to mixed feeders. The percentage of abrasive food components like grass in the diet of this species was probably close to 10%. This ratio suggests Miotragocerus is intermediate between the two hipparionine horse species of this early Turolian (MN11) palaeoenvironment.  相似文献   
85.
The C-terminal region of the Leptospiral immunoglobulin-like A protein (LigA) contains six carboxy-terminal Ig-like repeat domains (LigANI). Subunit vaccine preparations based on recombinant LigANI produced in Escherichia coli, are promising vaccine candidates, albeit with variable efficacy. In the present study, LigANI was expressed in the methylotrophic yeast Pichia pastoris using a 12 L bioreactor to produce mannosylated LigANI (mLigANI) for use in a vaccine preparation against leptospirosis. Hamsters immunized with a mLigANI vaccine preparation produced a significant IgG antibody response (P < 0.001) and were protected (83.3 %; P < 0.001) against lethal challenge with 36× LD50 of a virulent strain of L. interrogans serovar Copenhageni. A vaccine preparation based on demannosylated mLigANI (nmLigANI) elicited an immune response in hamsters, but did not afford protection. The production of mLigANI in bioreactor by P. pastoris yielded ~50 mg L?1 of recombinant protein. P. pastoris is a potential platform for the production of leptospiral antigens on an industrial scale. The results demonstrate that LigANI secreted by P. pastoris on mannosylated form (mLigANI) protect hamsters as subunit vaccine of L. interrogans lethal infection.  相似文献   
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Abundance and length of the highly-targeted snapper Chysophrys auratus were compared between sites in ''no take'' areas (Sanctuary Zones: SZ), partial protected areas which are fished (Habitat Protection Zones: HPZ), and areas outside (Outside) the Solitary Islands Marine Park (SIMP), Australia. Baited Remote Underwater Video (BRUV) sampling on shallow rocky reef (15 - 25 m) was conducted annually from 2002 until 2014 in the Austral-winter, covering the decade after these marine park zones were established (2002). Additional deeper sites (25 - 40 m) were sampled in 2010-2011 to assess if findings were more-broadly applicable. Lengths were measured using stereo-BRUVs from 2011-2014. Snapper were significantly more abundant in SZ overall and in most years compared with the other two management types, which did not significantly differ. Snapper rapidly increased after 2 - 3 years protection in all management types, especially SZ. Snapper were present on more SZ deployments than HPZ and Outside after the same period. The positive SZ response in snapper abundance on shallower reef was also found at a broader spatial scale on deeper sites. Again the two fished management types did not show significant differences among each other. There was considerable variation in snapper abundance between years, with strong peaks in 2005, 2009 and 2014 especially in SZ. Abundances remained higher in SZ in the year or two following a strong peak, but decreased to similar abundances to fished areas before the next peak. Snapper length frequency distribution significantly differed between SZ and both fished management types, with more larger snapper within SZ including a higher proportion (58%) that were legal-sized (>25.7 cm FL). HPZ and Outside did not significantly differ from each other, and were dominated by individuals below legal size. Overall, SZ''s have positively influenced abundance and length of snapper on these subtropical rocky reefs.  相似文献   
88.
The broader context for the formal darwinism project established by two of the commentators, in terms of reconciling the Modern Synthesis with Darwinian arguments over design and in terms of links to other types of selection and design, is discussed and welcomed. Some overselling of the project is admitted, in particular of whether it claims to consider all organic design. One important fundamental question raised in two commentaries is flagged but not answered of whether design is rightly represented by an optimisation program, and another from one commentary of whether the coreplicon dissolves in the face of multi-generational imprinting. Calls for the project to be extended to design at levels above and below the individual are considered sympathetically, but judged impractical at the high level of abstraction of the project. All claims of substantive technical error are emphatically rejected. Close technical readings are welcomed that, among other things, represent the project as 'axiomatizing fitness'. The prospects for the project are set out in the light of this highly varied set of commentaries.  相似文献   
89.
This study describes a versatile computational method to determine the hydrophobicity of small peptides at the atomic level. Free energies of transfer for individual atoms in peptide structures were derived, utilising two specifically defined parameters: (i) the water-excluding distance to define the dynamic interface between a peptide solute and its surrounding solvent and (ii) the corresponding hydrophobicity index as a relative measure for water occlusion/repulsion. The method was tested on a range of small peptide models (Ac-X-NH2, G-X-G, Ac-WL-X-LL and Ac-GG-X-GG-NH2) and several derivatives of these structures, whereby X was any of the 20 most common amino acids that naturally occur in polypeptides or proteins. The advantage of this new method lies in its versatility, ease to implement and capability to provide information on the hydrophobicity characteristics at the atomic level. The approach also encapsulates the impact of factors that influence these properties, but which have hitherto been difficult to accurately quantify, e.g. steric hindrance or proximity effects due to nearby polarised atoms. The method is not conditional on the knowledge of hydrophobicity parameters from the literature and does not require a sophisticated computer software/hardware to enable the atomic solvent-accessible surface areas or other hydrophobicity parameters to be de novo obtained.  相似文献   
90.
The stress-activated protein kinase Gcn2 regulates protein synthesis by phosphorylation of translation initiation factor eIF2α. Gcn2 is activated in amino acid-deprived cells by binding of uncharged tRNA to the regulatory domain related to histidyl-tRNA synthetase, but the molecular mechanism of activation is unclear. We used a genetic approach to identify a key regulatory surface in Gcn2 that is proximal to the predicted active site of the HisRS domain and likely remodeled by tRNA binding. Mutations leading to amino acid substitutions on this surface were identified that activate Gcn2 at low levels of tRNA binding (Gcd- phenotype), while other substitutions block kinase activation (Gcn- phenotype), in some cases without altering tRNA binding by Gcn2 in vitro. Remarkably, the Gcn- substitutions increase affinity of the HisRS domain for the C-terminal domain (CTD), previously implicated as a kinase autoinhibitory segment, in a manner dampened by HisRS domain Gcd- substitutions and by amino acid starvation in vivo. Moreover, tRNA specifically antagonizes HisRS/CTD association in vitro. These findings support a model wherein HisRS-CTD interaction facilitates the autoinhibitory function of the CTD in nonstarvation conditions, with tRNA binding eliciting kinase activation by weakening HisRS-CTD association with attendant disruption of the autoinhibitory KD-CTD interaction.  相似文献   
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