FBXO44 promotes DNA replication-coupled repetitive element silencing in cancer cells

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A taxonomy of transcriptomic cell types across the isocortex and hippocampal formation

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Naphthazarin derivatives (II): formation of glutathione conjugate, inhibition of DNA topoisomerase-I and cytotoxicity.

6-(1-Hydroxyalkyl)-5,8-dimethoxy-1,4-naphthoquinones, expressing a higher reactivity in conjugation with glutathione, showed a greater potency in the inhibition of DNA topoisomerase-I and the cytotoxicity against L1210 cells than 2-(1-hydroxyalkyl)-DMNQ derivatives, implying the participation of electrophilic arylation in the bioactivities. In further study 6-(1-Hydroxyalkyl)-5,8-dimethoxy-1,4-naphthoquinones with an alkyl group of shorter chain length (C2-C6) exerted a greater bioactivities than those with longer chain length(>C6).     

Tropane alkaloid production by Agrobacterium rhizogenes transformed hairy root cultures of Atropa baetica Willk. (Solanaceae)

Atropa baetica hairy root cultures were induced after infecting stem segments with Agrobacterium rhizogenes strain ATCC 15834. Accumulation of the tropane alkaloids atropine and scopolamine by hairy roots cultured in half- and full-strength Murashige and Skoog (MS) medium was high, although this was not growth associated. These alkaloids were also released into both liquid media. Higher tropane alkaloids present both in hairy roots and liquid medium occurred in half MS medium, showing a clear relationship between slow growth of cultures and higher product accumulation. The pH of both nutrient media varied as culture progressed, and seemed to be associated with the release of scopolamine. GC-MS analyses showed the presence of a new compound, namely tigloylpseudotropine; moreover, 3α-isobutyryloxytropane, formerly found only in plant leaf tissue, was also identified in the hairy roots. Received: 18 August 1997 / Revision received: 30 November 1997 / Accepted: 20 January 1998     

A Bethlem myopathy Gly to Glu mutation in the von Willebrand factor A domain N2 of the collagen alpha3(VI) chain interferes with protein folding.

A single G1679E mutation in the amino-terminal globular domain N2 of the alpha3 chain of type VI collagen was found in a large family affected with Bethlem myopathy. Recombinant production of N2 ( approximately 200 residues) in transfected mammalian cells has now been used to examine the possibility that the mutation interfered with protein folding. The wild-type form and a G1679A mutant were produced at high levels and shown to fold into a stable globular structure. Only a small amount of secretion was observed for mutants G1679E and G1679Q, which apparently were efficiently degraded within the cells. Homology modeling onto the related von Willebrand factor A1 structure indicated that substitution of G1679 by the bulky E or Q cannot be accommodated without considerable changes in the folding pattern. This suggests protein misfolding as a molecular basis for this particular mutation in Bethlem myopathy, in agreement with radioimmunoassay data showing reduced levels of domain N2 in cultured fibroblasts from two patients.     

Photosynthesis,Transpiration, and Water Use Efficiency of Vegetative and Reproductive Shoots of Grassland Species from North-Eastern China

The differences in net photosynthetic rate (P _N), transpiration rate (E), and water use efficiency (WUE) between the vegetative and reproductive shoots of three native grass species from the grassland of northeastern China [grey-green and yellow green populations of Leymus chinensis (Trin.) Tzvel., Puccinellia tenuiflora (Griseb) Scrib & Merr, Puccinellia chinampoensis Ohwi] were compared. The two type shoots experienced similar habitats, but differed in leaf life-span and leaf area. The leaf P _N and WUE for the vegetative shoots were significantly higher than those for the reproductive shoots in the grasses, while their E were remarked lower in the dry season. Relative lower leaf P _N and WUE for the reproductive shoots of grassland grasses may explain the facts of lower seed production and the subordinate role of seed in the grassland renewal in north-eastern China.     

Bacterial reduction of hexavalent molybdenum to molybdenum blue

A bacterium that was able to tolerate and reduce as high as 50 mM of sodium molybdate to molybdenum blue has been isolated from a metal recycling ground. The isolate was tentatively identified as Serratia sp. strain Dr.Y8 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. ANOVA analysis showed that isolate Dr.Y8 produced significantly higher (P < 0.05) amount of Mo-blue with 3, 5.1 and 11.3 times more molybdenum blue than previously isolated molybdenum reducers such as Serratia marcescens strain Dr.Y6, E. coli K12 and E. cloacae strain 48, respectively. Its molybdate reduction characteristics were studied in this work. Electron donor sources such as sucrose, mannitol, fructose, glucose and starch supported molybdate reduction. The optimum phosphate, pH and temperature that supported molybdate reduction were 5 mM, pH 6.0 and 37°C, respectively. The molybdenum blue produced from cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, silver, copper and mercury resulted in approximately 61, 57, 80, and 69% inhibition of the molybdenum-reducing activity at 1 mM, respectively. The reduction characteristics of strain Dr.Y8 suggest that it would be useful in future molybdenum bioremediation.