Nickel translocation via the phloem in the hyperaccumulator Noccaea caerulescens (Brassicaceae)

Plant and Soil - This study evaluated the effect of phloem translocation on Ni accumulation in the hyperaccumulator Noccaea caerulescens. The first experiment assessed the metal and organic...     

Molecular cytogenetic characterization of a new wheat-rye 1BL•1RS translocation line expressing superior stripe rust resistance and enhanced grain yield

Main conclusion

A new wheat-rye 1BL?1RS translocation line, with the characteristics of superior stripe rust resistance and high thousand-kernel weight and grain number per spike, was developed and identified from progenies of wheat-rye- Psathyrostachys huashanica trigeneric hybrids.

Abstract

The wheat-rye 1BL?1RS translocation line from Petkus rye has contributed substantially to the world wheat production. However, due to extensive growing of cultivars with disease resistance genes from short arm of rye chromosome 1R and coevolution of pathogen virulence and host resistance, these cultivars successively lost resistance to pathogens. In this study, a new wheat-rye line K13-868, derived from the progenies of wheat-rye-Psathyrostachys huashanica trigeneric hybrids, was identified and analyzed using fluorescence in situ hybridization (FISH), genomic in situ hybridization (GISH), acid polyacrylamide gel electrophoresis (A-PAGE), and molecular markers. Cytological studies indicated that the mean chromosome configuration of K13-868 at meiosis was 2n = 42 = 0.14 I + 18.78 II (ring) + 2.15 II (rod). Sequential FISH and GISH results demonstrated that K13-868 was a compensating wheat-rye 1BL?1RS Robertsonian translocation line. Acid PAGE analysis revealed that clear specific bands of rye 1RS were expressed in K13-868. Simple sequence repeat (SSR) and rye 1RS-specific markers ω-sec-p1/ω-sec-p2 and O-SEC5′-A/O-SEC3′-R suggested that the 1BS arm of wheat had been substituted by the 1RS arm of rye. At the seedling and adult growth stage, compared with its recurrent wheat parent SM51 and six other wheat cultivars containing the 1RS arm in southwestern China, K13-868 showed high levels of resistance to stripe rust (Puccinia striiformis f. sp. tritici, Pst) pathogens prevalent in China, which are virulent to Yr10 and Yr24/Yr26. In addition, K13-868 expresses higher thousand-kernel weight and more grain number per spike than these controls in two growing seasons, suggesting that this line may carry yield-related genes of rye. This translocation line, with significant characteristics of resistance to stripe rust and high thousand-kernel weight and grain number per spike, could be utilized as a valuable germplasm for wheat improvement.

     

Conversion of glycerol to 1,3-dihydroxyacetone by glycerol dehydrogenase co-expressed with an NADH oxidase for cofactor regeneration

Objectives

To investigate the efficiency of a cofactor regeneration enzyme co-expressed with a glycerol dehydrogenase for the production of 1,3-dihydroxyacetone (DHA).

Results

In vitro biotransformation of glycerol was achieved with the cell-free extracts containing recombinant GlyDH (glycerol dehydrogenase from Escherichia coli), LDH (lactate dehydrogenase form Bacillus subtilis) or LpNox1 (NADH oxidase from Lactobacillus pentosus), giving DHA at 1.3 g l^?1 (GlyDH/LDH) and 2.2 g l^?1 (GlyDH/LpNox1) with total turnover number (TTN) of NAD⁺ recycling of 6039 and 11100, respectively. Whole cells of E. coli (GlyDH–LpNox1) co-expressing both GlyDH and LpNox1 were constructed and converted 10 g glycerol l^?1 to DHA at 0.2–0.5 g l^?1 in the presence of zero to 2 mM exogenous NAD⁺. The cell free extract of E. coli (GlyDH–LpNox) converted glycerol (2–50 g l^?1) to DHA from 0.5 to 4.0 g l^?1 (8–25 % conversion) without exogenous NAD⁺.

Conclusions

The disadvantage of the expensive consumption of NAD⁺ for the production of DHA has been overcome.

     

<Emphasis Type="Italic">Enterococcus faecalis</Emphasis> promotes osteoclast differentiation within an osteoblast/osteoclast co-culture system

Objective

To investigate the effects of heat-killed Enterococcus faecalis ATCC 29212 and P25RC clinical strain (derived from an obturated root canal with apical periodontitis) on osteoclast differentiation within an osteoblast/osteoclast co-culture system.

Results

Heat-killed E. faecalis significantly increased the proportion of multinucleated osteoclastic cells (MNCs) within the co-culture system. The IL-6 level was significantly increased upon exposure to heat-killed E. faecalis. Gene expression levels of NFATc1 and cathepsin K were significantly up-regulated compared to the untreated control. EphrinB2 and EphB4 expressions at both the mRNA and protein levels were also significantly upregulated compared to the untreated control.

Conclusions

Heat-killed E. faecalis can induce osteoclast differentiation within the osteoblast/osteoclast co-culture system in vitro, possibly through ephrinB2-EphB4 bidirectional signaling.

     

Dynamic changes of histone H3 lysine 9 following trimethylation in bovine oocytes and pre-implantation embryos

Objectives

We have examined dynamic changes of histone H3 lysine 9 following trimethylation (H3K9me3), the mRNA expression levels of SUV39H1 and SUV39H2 in bovine oocytes and the role in the development of in vitro fertilization (IVF) pre-implantation embryos.

Results

There were strong H3K9me3 signals in germinal vesicle (GV) oocytes but no signals in MII oocytes. H3K9me3 signals were maintained during IVF pre-implantation embryo development. SUV39H1 and SUV39H2 showed significantly higher mRNA expression levels in GV oocytes than MII oocytes (P < 0.01). SUV39H1 showed high mRNA expression level in two-cell embryos, however, SUV39H2 showed high mRNA expression level in four-cell embryos. In other development stage, SUV39H1 and SUV39H2 showed low expression levels.

Conclusion

Bovine IVF pre-implantation embryos maintain strong H3K9me3 signals and SUV39H1 and SUV39H2 are highly expressed at the early development stage of pre-implantation embryos.

     

Endoglucanase enzymatic modification of kraft pulp during recycling

Objective

To investigate the cellulose modification process on kraft pulp during recycling by mono-endoglucanase.

Results

Pichia pastoris expressing endoglucanase, EG1, was grown in a 10 l fermenter yielding a high carboxymethyl cellulase (CMCase) activity of 340 U mg^?1. EG1-mediated modification of kraft pulp resulted in a paper sheet with the tensile index and burst index increased by 10 and 6.5 %, respectively. The kink index (indicating abrupt bends in fibres) of the enzyme-treated group decreased sharply by 45 % after the first recycling, compared with a reduction of only 1 % in the control group. Furthermore, EG1 treatment decreased the growth of crystallinity from 73.5 to 73.2 % and crystal size from 7.45 to 7.21 nm, which alleviated paper aging.

Conclusion

Endoglucanase EG1 modifies the interfacial properties of fibers, which affects fibre morphology during the recycling process and improves the technical properties of the resulting pulp and paper.