Theory for designing mechanically stable single- and double-walled SiGe nanopeapods

Journal of Molecular Modeling - The adsorption and inhibition mechanism of chain length increase and group substitution of imidazole tetrafluoroborate derivatives for the corrosion inhibition of...     

Ancistrolikokine D,a 5,8'-coupled naphthylisoquinoline alkaloid,and related natural products from Ancistrocladus likoko

A new naphthylisoquinoline alkaloid, ancistrolikokine D, and the likewise 5,8'-coupled alkaloid ancistroealaine A, as well as two further, biosynthetically related, but nitrogen-free natural products, ancistronaphthoic acid B and cis-isoshinanolone, have been isolated from Ancistrocladus likoko J. LEACUTE;ONARD (Ancistrocladaceae). The 5,8'-coupling of the new alkaloids and of the alkaloids isolated earlier hints at a close phylogenetic relationship of A. likoko to other Central African Ancistrocladus species. The compounds show moderate activities against Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei rhodesiense.     

Making Activity Recognition Robust against Deceptive Behavior

Healthcare services increasingly use the activity recognition technology to track the daily activities of individuals. In some cases, this is used to provide incentives. For example, some health insurance companies offer discount to customers who are physically active, based on the data collected from their activity tracking devices. Therefore, there is an increasing motivation for individuals to cheat, by making activity trackers detect activities that increase their benefits rather than the ones they actually do. In this study, we used a novel method to make activity recognition robust against deceptive behavior. We asked 14 subjects to attempt to trick our smartphone-based activity classifier by making it detect an activity other than the one they actually performed, for example by shaking the phone while seated to make the classifier detect walking. If they succeeded, we used their motion data to retrain the classifier, and asked them to try to trick it again. The experiment ended when subjects could no longer cheat. We found that some subjects were not able to trick the classifier at all, while others required five rounds of retraining. While classifiers trained on normal activity data predicted true activity with ~38% accuracy, training on the data gathered during the deceptive behavior increased their accuracy to ~84%. We conclude that learning the deceptive behavior of one individual helps to detect the deceptive behavior of others. Thus, we can make current activity recognition robust to deception by including deceptive activity data from a few individuals.     

Chemoprotective effects of carnosine against genotoxicity induced by cyclophosphamide in mice bone marrow cells

The protective effects of carnosine as a natural dipeptide were investigated in mouse bone marrow cells against genotoxicity induced by cyclophosphamide. Mice were injected with solutions of carnosine at three different doses (10, 50 and 100?mg kg(-1) bw) for five consecutive days. On the fifth day of treatment, mice were injected cyclophosphamide and killed after 24?h. The frequency of micronuclei in polychromatic erythrocytes and the ratio of polychromatic erythrocyte/polychromatic erythrocyte?+?normochromatic erythrocyte [PCE/(PCE?+?NCE)] were evaluated by May-Grunwald/Giemsa staining. Histopathology of bone marrow was examined in mice treated with cyclophosphamide and carnosine. Carnosine significantly reduced micronucleated polychromatic erythrocytes (MnPCEs) induced by cyclophosphamide at all three doses. Carnosine at dose of 100?mg kg(-1) bw reduced MnPCEs 3.76-fold and completely normalized the PCE/(PCE?+?NCE) ratio. Administration of carnosine inhibited bone marrow toxicity induced by cyclophosphamide. It appeared that carnosine with protective activity reduced the oxidative stress and genotoxicity induced by cyclophosphamide in bone marrow cells of mice. Copyright ? 2012 John Wiley & Sons, Ltd.     

Cyclic AMP-adenosine binding protein/S-adenosylhomocysteinase from mouse liver. A fraction of adenosine bound is converted to adenine.

1. Adenosine bound to the cyclic AMP-adenosine binding protein/S-adenosylhomocysteinase from mouse liver was partly converted to a product which was identified as adenine in four chromatographic systems. Ribose was formed in equivalent amounts. 2. The time course of the reaction was characterized by an initial burst phase lasting for less than one second followed by a slow progressive phase. The reaction was partly reversed by prolonged incubation, slow denaturation of the protein, dilution of the incubation mixture and removal of adenosine by converting it to inosine by the enzyme adenosine deaminase. 3. Both the ATP-treated (Ueland, P.M. and D?skeland, S.O. (1978) Arch. Biochem. Biophys. 185, 195--203) and the non-treated protein were subjected to polyacrylamide gel electrophoresis at pH 8.8. The adenosine-adenine, the cyclic AMP binding activities and the conversion activity comigrated with the main protein band, indicating that these properties reside on the same protein molecule. 4. Adenine generated by hydrolysis of adenosine was mainly bound to the protein as judged by nearly complete reversion of the conversion upon dilution in the presence of excess unlabelled adenine and by Sephadex G-25 chromatography. 5. The conversion of adenosine to inosine by the enzyme adenosine deaminase was decreased in the presence of the binding protein. 6. Adenine formation could also be demonstrated under condition of enzymic formation of S-adenosylhomocysteine, i.e. in the presence of hymocysteine.     

Genetic variation and relationships between isolates and species of the entomopathogenic nematode genus Heterorhabditis deciphered through isozyme profiles

We studied variation in isozyme patterns of 8 metabolic enzymes in 5 species of Heterorhabditis (H. bacteriophora, H. indica, H. marelata, H. megidis, and H. zealandica) comprising 18 isolates. Isozyme banding patterns of all the 8 enzymes were species specific; however, 3 enzymes, i.e., arginine kinase, fumarate hydratase, and malate dehydrogenase, displayed distinct patterns among all the 18 isolates. Phylogenetic analysis of the isozyme patterns produced dendrograms depicting a high degree of genetic variation among Heterorhabditis species, with the average pairwise distance of 0.2000. Trees constructed using different phylogenetic methods showed a relatively close genetic relationship between H. megidis and H. zealandica and between H. bacteriophora and H. indica. Also, H. bacteriophora HP88 was the most distant species from H. megidis (UK isolate), H. marelatus (Oregon isolate), and H. zealandica (X1 isolate) with pairwise distance of 0.1957, 0.2228, and 0.2120, respectively. Phylogenetic analysis also revealed genetic variation among H. bacteriophora isolates with the average pairwise distance of 0.1507. GPS2 and GPS3 were the most closely related isolates with the average distance of only 0.0870, followed by GPS1 and GPS2 with average distance of 0.1087. In contrast, KMD19 and HP88, OH25, and HP88, and OH25 and Acows isolates were the most divergent populations with a pairwise distance of 0.2011 and 37 character differences. Pairwise distance analysis also revealed that genetic divergence among populations of H. bacteriophora is relatively independent of geographic distance. Overall, these results demonstrate strong subspecies structuring in H. bacteriophora.     

Glypican 4 mediates Wnt transport between germ layers via signaling filopodia

Glypicans influence signaling pathways by regulating morphogen trafficking and reception. However, the underlying mechanisms in vertebrates are poorly understood. In zebrafish, Glypican 4 (Gpc4) is required for convergence and extension (C&E) of both the mesoderm and endoderm. Here, we show that transgenic expression of GFP-Gpc4 in the endoderm of gpc4 mutants rescued C&E defects in all germ layers. The rescue of mesoderm was likely mediated by Wnt5b and Wnt11f2 and depended on signaling filopodia rather than on cleavage of the Gpc4 GPI anchor. Gpc4 bound both Wnt5b and Wnt11f2 and regulated formation of the filopodia that transport Wnt5b and Wnt11f2 to neighboring cells. Moreover, this rescue was suppressed by blocking signaling filopodia that extend from endodermal cells. Thus, GFP-Gpc4–labeled protrusions that emanated from endodermal cells transported Wnt5b and Wnt11f2 to other germ layers, rescuing the C&E defects caused by a gpc4 deficiency. Our study reveals a new mechanism that could explain in vivo morphogen distribution involving Gpc4.     

Sequestration of adenosine in crude extract from mouse liver and other tissues

Adenosine (1 μM) was incubated in the presence of dialyzed crude tissue extract from mouse liver and its degradation determined. At high concentration of tissue extract, a fraction of adenosine was not metabolized. This phenomenon, termed sequestration of adenosine, was shown to be affected in the same way by the same factors (pH, salt, reducing agent and adenine) as those affecting the protection of adenosine against deamination in the presence of the purified cyclic AMP-adenosine binding protein/S-adenosylhomocysteinase from mouse liver (Sæbø, J. and Ueland, P.M. (1979) Biochim. Biophys. Acta 587, 333–340). These data point to a role of this protein in the sequestration of adenosine in crude extract.The sequestration potency in crude extract could be determined by diluting the extract in the presence of a constant amount of adenosine deaminase added to the tissue extract. Under these conditions there was linearity of adenosine not available for degradation versus the concentration of tissue extract, and a total recovery of the sequestration potency of purified binding protein added to the crude extract was observed.The tissue level of the cyclic AMP-adenosine binding protein/S-adenosylhomocysteinase in mouse liver was determined by two independent procedures based on the sequestration of adenosine and the hydrolysis of S-adenosylhomocysteine, respectively. The intracellular concentration was calculated to be 10 μM.The sequestration of adenosine in crude extract from mouse, rat, rabbit and bovine tissues was determined and showed requirements similar to those of the sequestration in mouse liver extract.The ability to sequester adenosine was high in liver and decreased in the following order: liver, kidney, adrenal cortex, brain, uterus, cardiac and skeletal muscle.     

mRNA transfection of DC in the immature or mature state: comparable in vitro priming of Th and cytotoxic T lymphocytes against DC electroporated with tumor cell line-derived mRNA

BACKGROUND: The use of mRNA in vaccine studies has generally been through loading or transfection of immature DC followed by a maturation step. A recent study has suggested that this strategy may result in inferior priming of cytotoxic T lymphocytes (CTL). Furthermore the study did not address any possible effects on the priming of CD4(+) T-cell responses. METHODS: We compared mRNA transfection of mature DC with that of immature DC, using as a read-out their capacity to prime autologous T cells during one cycle of in vitro stimulation. In this model system we used mRNA from the tumor cell line Jurkat E6. DC transfected at either the immature stage (day 5) or mature stage (day 7) displayed a similar phenotype. RESULTS: Interestingly, no major differences in their ability to prime CD4 and CD8 T-cell responses were observed. As in vitro priming to some extent may reflect the capacity of these DC to prime T cells in vivo after vaccination, these studies support the use of mRNA-transfected mature DC in clinical protocols. DISCUSSION: Transfection of DC at the end of the maturation process represents a logistical improvement in the GMP production of mRNA-transfected DC for clinical protocols.     

8-O-methyldioncophyllinol B and revised structures of other 7,6'-coupled naphthylisoquinoline alkaloids from Triphyophyllum peltatum (Dioncophyllaceae)

The isolation and structural elucidation of a new naphthylisoquinoline alkaloid, 8-O-methyldioncophyllinol B, from Triphyophyllum peltatum (Hutch. et Dalz.) Airy Shaw (Dioncophyllaceae) is described, together with the revised structures of other 'B-type' compounds previously misidentified as dioncophylline D, dioncophyllinol D, and 8-O-methyldioncophylline D. All of the presently described structures are 7,6'-coupled and thus have to be addressed as 'B-type' naphthylisoquinoline alkaloids. This is in contrast to the initially defined 'D-type' structures, which are 7,8'-coupled as confirmed by a total synthesis of dioncophylline D. Some of these natural and synthetic naphthylisoquinolines were found to display good in vitro antiplasmodial activities.