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The occurrence of distinct (2'-5')(A)n-synthetase activities has recently been documented in cytoplasmic and nuclear extracts of several interferon (IFN)-treated cell lines. Since a role has been proposed for (2'-5')(A)n synthetase in the control of cell growth and differentiation, we examined the subcellular distribution of (2'-5')(A)n-synthetase activity both in IFN-treated undifferentiated Friend leukemia cells (FLCs) and during dimethyl-sulfoxide (DMSO)-induced erythroid differentiation of FLCs. Both the nuclear and cytoplasmic (2'-5')(A)n activities were modulated to the same extent by IFNs and DMSO. No evidence for a causal relationship between enzyme activation and FLC differentiation was found.  相似文献   
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Espíndola, A., Buerki, S., Jacquier, A., Je?ek, J. & Alvarez, N. (2012). Phylogenetic relationships in the subfamily Psychodinae (Diptera, Psychodidae). —Zoologica Scripta, 41, 489–498. Thanks to recent advances in molecular systematics, our knowledge of phylogenetic relationships within the order Diptera has dramatically improved. However, relationships at lower taxonomic levels remain poorly investigated in several neglected groups, such as the highly diversified moth‐fly subfamily Psychodinae (Lower Diptera), which occurs in numerous terrestrial ecosystems. In this study, we aimed to understand the phylogenetic relationships among 52 Palearctic taxa from all currently known Palearctic tribes and subtribes of this subfamily, based on mitochondrial DNA. Our results demonstrate that in light of the classical systematics of Psychodinae, none of the tribes sensu Je?ek or sensu Vaillant is monophyletic, whereas at least five of the 12 sampled genera were not monophyletic. The results presented in this study provide a valuable backbone for future work aiming at identifying morphological synapomorphies to propose a new tribal classification.  相似文献   
285.
1 Experiments were conducted to determine whether propagule loads on the twig beetles Pityophthorus setosus and Pityophthorus carmeli (Coleoptera: Scolytidae) influence the pathogen infection of the host tree in the Monterey pine- Fusarium circinatum system.
2 On an average, F. circinatum was isolated from 2.6% and 3.3% of trapped P. setosus and P. carmeli , respectively, although the isolation percentages varied over the season, being highest in the spring and lowest in late summer and fall for both species. Mean pathogen load was 13.4 and 22.6 propagules per beetle, on P. setosus and P. carmeli , respectively, and decreased from May to November for both species. The pathogen was also isolated from approximately 55% of both beetle species that emerged from infected branches. Mean propagule load on emerged P. setosus and P. carmeli was 39 and 66.5, respectively.
3 On the basis of these data, beetle species were treated with one of three propagule loads (low, medium, high) and caged onto live branches to determine whether they could transmit the pathogen. At all propagule loads, both species transmitted the pathogen, and transmission percentage and lesion length, a measure of tree susceptibility, were positively correlated with propagule load.
4 To investigate further whether the previous transmission by beetles could affect response of the same trees to subsequent infection with F. circinatum , different branches were inoculated on the same trees used in the transmission study, and lesion lengths were measured. Lesion lengths were lower on trees that had been previously exposed to beetles treated with high or medium propagule loads than on trees that had previously been exposed to beetles treated with low propagule loads. This suggests that the initial infection by beetles carrying high or medium propagule loads induced resistance to subsequent infections of the host, whereas infections caused by beetles with low propagule loads did not.  相似文献   
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Novel chiral benzimidazole amine hybrids ( 4a – 4d ) were synthesized from commercially available amine [(R)- (+)-phenylethylamine, (−) (S)-(-)-phenylethylamine, (−) (R)-(-)-cyclohexylethylamine, (S)-(+)-cyclohexylethylamine] and 2-(chloromethyl)-N-tosyl-1H-benzimidazole. The synthesized compounds ( 4a – 4d ) were characterized by IR, NMR, and LC/MS analysis. The inhibitory effect of 4a – 4d on human erythrocytes carbonic anhydrase I (hCA-I), II (hCA-II), and acetylcholinesterase (AChE) activity was investigated. For hCA-I, the IC50 values of 4a – 4d were found to be 4.895 μM, 1.750 μM, 0.173 μM, and 0.620 μM, respectively, and for hCA-II, the IC50 values of 4a – 4d were found to be 0.469 μM, 0.380 μM, 0.233 μM, 0.635 μM, respectively. Furthermore, IC50 values of 4a – 4d on AChE were found as 87.5 nM, 100 nM, 26.92 nM, and 100 nM, respectively. In addition, molecular docking analysis was performed to evaluate the affinity of 4a – 4d against hCA-I, hCA-II, and AChE and explain their binding interactions.  相似文献   
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