An Arabidopsis thaliana protein homologous to cyanobacterial high-light-inducible proteins

An Arabidopsis thaliana cDNA clone encoding a novel 110 amino acid thylakoid protein has been sequenced. The in vitro synthesized protein is taken up by intact chloroplasts, inserted into the thylakoid membrane and the transit peptide is cleaved off during this process. The mature protein is predicted to contain 69 amino acids, to form one membrane-spanning -helix and to have its N-terminus at the stromal side of the thylakoid membrane. The protein showed similarity to the LHC, ELIP and PsbS proteins of higher plants, but more pronounced to the high-light-inducible proteins (HLIPs) of cyanobacteria and red algae, to which no homologue previously has been detected in higher plants. As for HLIP and ELIP, high light increases the mRNA levels of the corresponding gene. Sequence comparisons indicate that the protein may bind chlorophyll and form dimers in the thylakoid membrane. The level of expression of the protein seems to be far lower than that of normal PSI and PSII subunits.     

Preliminary estimates of the potential for carbon mitigation in European soils through no-till farming

In this paper we estimate the European potential for carbon mitigation of no-till farming using results from European tillage experiments. Our calculations suggest some potential in terms of (a) reduced agricultural fossil fuel emissions, and (b) increased soil carbon sequestration. We estimate that 100% conversion to no-till farming would be likely to sequester about 23 Tg C y^–1 in the European Union or about 43 Tg C y^–1 in the wider Europe (excluding the former Soviet Union). In addition, up to 3.2 Tg C y^–1 could be saved in agricultural fossil fuel emissions. Compared to estimates of the potential for carbon sequestration of other carbon mitigation options, no-till agriculture shows nearly twice the potential of scenarios whereby soils are amended with organic materials. Our calculations suggest that 100% conversion to no-till agriculture in Europe could mitigate all fossil fuel-carbon emissions from agriculture in Europe. However, this is equivalent to only about 4.1% of total anthropogenic CO₂-carbon produced annually in Europe (excluding the former Soviet Union) which in turn is equivalent to about 0.8% of global annual anthropogenic CO₂-carbon emissions.     

Effects of fine‐scale genetic structure on male mating success in gynodioecious Beta vulgaris ssp. maritima

Plant mating systems are known to influence population genetic structure because pollen and seed dispersal are often spatially restricted. However, the reciprocal outcomes of population structure on the dynamics of polymorphic mating systems have received little attention. In gynodioecious sea beet (Beta vulgaris ssp. maritima), three sexual types co‐occur: females carrying a cytoplasmic male sterility (CMS) gene, hermaphrodites carrying a non‐CMS cytoplasm and restored hermaphrodites that carry CMS genes and nuclear restorer alleles. This study investigated the effects of fine‐scale genetic structure on male reproductive success of the two hermaphroditic forms. Our study population was strongly structured and characterized by contrasting local sex‐ratios. Pollen flow was constrained over short distances and depended on local plant density. Interestingly, restored hermaphrodites sired significantly more seedlings than non‐CMS hermaphrodites, despite the previous observation that the former produce pollen of lower quality than the latter. This result was explained by the higher frequency of females in the local vicinity of restored (CMS) hermaphrodites as compared to non‐CMS hermaphrodites. Population structure thus strongly influences individual fitness and may locally counteract the expected effects of selection, suggesting that understanding fine scale population processes is central to predicting the evolution of gender polymorphism in angiosperms.     

A Protein Deep Sequencing Evaluation of Metastatic Melanoma Tissues

Malignant melanoma has the highest increase of incidence of malignancies in the western world. In early stages, front line therapy is surgical excision of the primary tumor. Metastatic disease has very limited possibilities for cure. Recently, several protein kinase inhibitors and immune modifiers have shown promising clinical results but drug resistance in metastasized melanoma remains a major problem. The need for routine clinical biomarkers to follow disease progression and treatment efficacy is high. The aim of the present study was to build a protein sequence database in metastatic melanoma, searching for novel, relevant biomarkers. Ten lymph node metastases (South-Swedish Malignant Melanoma Biobank) were subjected to global protein expression analysis using two proteomics approaches (with/without orthogonal fractionation). Fractionation produced higher numbers of protein identifications (4284). Combining both methods, 5326 unique proteins were identified (2641 proteins overlapping). Deep mining proteomics may contribute to the discovery of novel biomarkers for metastatic melanoma, for example dividing the samples into two metastatic melanoma “genomic subtypes”, (“pigmentation” and “high immune”) revealed several proteins showing differential levels of expression. In conclusion, the present study provides an initial version of a metastatic melanoma protein sequence database producing a total of more than 5000 unique protein identifications. The raw data have been deposited to the ProteomeXchange with identifiers PXD001724 and PXD001725.     

Large scale geographic clines of parasite damage to Populus tremula L.

According to the geographic mosaic theory of coevolution (GMTC), clines of traits reflecting local co‐adaptation (including resistance genes) should be common between a host and its parasite and should persist across time. To test the GMTC‐assumption of persistent clinal patterns we compared the natural prevalence of two parasites on aspen Populus tremula trees: mining moths of the genus Phyllocnistis and leaf rust Melampsora spp. Damage data were collated from the Swedish National Forest Damage Inventory (2004–2006). In addition, occurrence of the parasites was scored in field conditions in two common gardens in the north and south of Sweden over five growing seasons (2004–2008), then related to biomass (stem height and diameter) and to concentrations of eleven leaf phenolics. Phyllocnistis mainly occurred in the northern garden, a distribution range which was confirmed by the countrywide inventory, although Phyllocnistis was more abundant on southern clones, providing evidence for possible local maladaptation. Melampsora occurred all over the country and in both gardens, but built up more quickly on northern clones, which suggests a centre of local clone maladaptation in the north. Stem growth also followed a clinal pattern as did the concentration of three phenolic compounds: benzoic acid, catechin and cinnamic acid. However, only benzoic acid was related to parasite presence: negatively to Phyllocnistis and positively to Melampsora and it could thus be a potential trait under selection. In conclusion, clines of Phyllocnistis were stronger and more persistent compared to Melampsora, which showed contrasting clines of varying strength. Our data thus support the assumption of the GMTC model that clines exist in the border between hot and cold spots and that they may be less persistent for parasites with an elevated gene flow, and/or for parasites which cover relatively larger hot spots surrounded by fewer cold spots.     

Molecular cloning and expression profiles of calreticulin gene from the diamondback moth,Plutella xylostella

Calreticulin (CRT) plays pivotal roles in Ca²⁺ homeostasis, molecular chaperoning, infection, inflammation and innate immunity. In an attempt to study the involvement of CRT in innate immunity, the full-length cDNA of calreticulin (PxCRT) was cloned from the diamondback moth, Plutella xylostella. It consists of 1674 bp (excluding poly-A tail) with a longest open reading frame (ORF) of 1197 bp encoding 398 amino acids. In silico analysis of PxCRT ORF reveals that it has various repeat motifs and endoplasmic reticulum retention signal found in all the calreticulin proteins. As expected, high amino acid sequence identities were found from other CRTs identified from Bombyx mori (87%), Galleria mellonella (87%), Apis mellifera (74%), Anopheles gambiae (74%), Tribolium castaneum (73%), Culex quinquefasciatus (73%), Rhodnius prolixus (72%), Nasonia vitripennis (71%), Drosophila melanogaster (71%) and Haemaphysalis qinghaiensis (68%). During development, P. xylostella expressed PxCRT predominantly in the pupal stage. In addition, spatial expression pattern analysis indicates that PxCRT was highly expressed in the silk gland. PxCRT mRNA, furthermore, was strongly induced 3 to 6 h after laminarin treatment, suggesting that PxCRT appears to be involved in immune responses and also plays an important role in the silk gland.