A rapid and efficient method for the synthesis of selectively S-Trt or S-Mmt protected Cys-containing peptides

Selective removal of protecting groups under different cleavage mechanisms could be an asset in peptide synthesis, since it provides the feasibility to incorporate different functional groups in similar reactive centres. However, selective protection/deprotection of orthogonal protecting groups in peptides is still challenging, especially for Cys-containing peptides, where protection of the cysteine side-chain is mandatory since the nucleophilic thiol can be otherwise alkylated, acylated or oxidized. Herein, we established a protocol for the synthesis of Cys-selective S-Trt or S-Mmt protected Cys-containing peptides, in a rapid way. This was achieved by, simply fine-tuning the carbocation scavenger in the final acidolytic release of the peptide from the solid support in the classic SPPS.     

Temporal and transient expression of olive enoyl-ACP reductase gene during flower and fruit development.

Enoyl-ACP reductase is a catalytic component of the fatty acid synthetase (FAS) type II system in plants that is involved in the de novo fatty acid biosynthesis in plastids. A cDNA encoding an enoyl-ACP reductase responsible for the removal of the trans-unsaturated double bonds to form saturated acyl-ACP has been isolated from a library made from ripening fruits of Olea europaea L. The predicted protein contains 393 amino acid residues including a consensus chloroplast specific transit peptide. A strong homology was observed when olive enoyl-ACP reductase aligned with other plant sequences. Southern hybridization analysis revealed that enoyl-ACP reductase is encoded by a single gene in olives. Northern hybridization showed a transient expression of the enoyl-ACP reductase (ENR) gene at early stages of drupe (5-7 weeks after flowering, WAF), embryo and endosperm (13-16 WAF) while in mesocarp (13-19 WAF) the expression remained at high levels. In situ hybridization showed particularly prominent expression in the palisade and vascular tissue of young leaves, the tapetum, developing pollen grains and vascular tissue of anthers and to less extent in the embryo sac and transmitting tissue of the carpel. The distinctive spatial and temporal regulation of the ENR gene is consistent with major roles, not only in thylakoid membrane formation and fatty acid deposition, but also in the provision of precursor molecules for the biosynthesis of oxilipins that are important in plant tissues involved in transportation and reproduction.     

Quantitative Analysis of the Chloroplast Molecular Chaperone ClpC/Hsp93 in Arabidopsis Reveals New Insights into Its Localization,Interaction with the Clp Proteolytic Core,and Functional Importance

The molecular chaperone ClpC/Hsp93 is essential for chloroplast function in vascular plants. ClpC has long been held to act both independently and as the regulatory partner for the ATP-dependent Clp protease, and yet this and many other important characteristics remain unclear. In this study, we reveal that of the two near-identical ClpC paralogs (ClpC1 and ClpC2) in Arabidopsis chloroplasts, along with the closely related ClpD, it is ClpC1 that is the most abundant throughout leaf maturation. An unexpectedly large proportion of both chloroplast ClpC proteins (30% of total ClpC content) associates to envelope membranes in addition to their stromal localization. The Clp proteolytic core is also bound to envelope membranes, the amount of which is sufficient to bind to all the similarly localized ClpC. The role of such an envelope membrane Clp protease remains unclear although it appears uninvolved in preprotein processing or Tic subunit protein turnover. Within the stroma, the amount of oligomeric ClpC protein is less than that of the Clp proteolytic core, suggesting most if not all stromal ClpC functions as part of the Clp protease; a proposal supported by the near abolition of Clp degradation activity in the clpC1 knock-out mutant. Overall, ClpC appears to function primarily within the Clp protease, as the principle stromal protease responsible for maintaining homeostasis, and also on the envelope membrane where it possibly confers a novel protein quality control mechanism for chloroplast preprotein import.     

Molecular diversity and distribution of eastern Atlantic and Mediterranean dogfishes Squalus highlight taxonomic issues in the genus

The alpha taxonomy of the globally distributed shark genus Squalus has been under intense investigation recently, and many new species have been described over the last decade. However, taxonomic uncertainty remains about several taxa. Without consistent nomenclature and the ability to reliably distinguish between the different Squalus species, basic data collection, downstream conservation and management efforts are seriously compromised. To aid in clarifying the taxonomic status of Squalus species in the eastern Atlantic and Mediterranean, we assessed species diversity at the molecular level and evaluated the consistency in species identification in the region. Samples from all nominal Squalus species recognized in the above regions were collected in an international effort and sequenced for regions of the mitochondrial COI and ND2 genes. These data were further analysed alongside publicly available sequences, including 19 of the 26 Squalus species globally recognized, to compare the regional genus‐level diversity with that found elsewhere. Our results confirm inconsistent species identification in the eastern Atlantic and Mediterranean Squalus, particularly concerning S. blainville and S. megalops, and reinforce the need to revise the status of S. megalops and S. mitsukurii as they may include several distinct species distributed around the world. The status of S. blainville is also discussed in the light of the current findings and its problematic taxonomic history.     

Human embryonal epithelial cells of the developing small intestinal crypts can express the Hodgkin-cell associated antigen Ki-1 (CD30) in spontaneous abortions during the first trimester of gestation

Background  

Ki-1 (CD30) antigen expression is not found on peripheral blood cells but its expression can be induced in vitro on T and B lymphocytes by viruses and lectins. Expression of CD30 in normal tissues is very limited, being restricted mainly to a subpopulation of large lymphoid cells; in particular, cells of the recently described anaplastic large cell lymphoma (ALCL), the Reed-Sternberg (RS) cells of Hodgkin's lymphoma and scattered large parafollicular cells in normal lymphoid tissues. More recent reports have described CD30 expression in non-hematopoietic and malignant cells such as cultured human macrophages, human decidual cells, histiocytic neoplastic cells, mesothelioma cells, embryonal carcinoma and seminoma cells.     

Stabilization of Reversed Replication Forks by Telomerase Drives Telomere Catastrophe

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Agriculture shapes the trophic niche of a bat preying on multiple pest arthropods across Europe: Evidence from DNA metabarcoding

The interaction between agricultural production and wildlife can shape, and even condition, the functioning of both systems. In this study, we i) explored the degree to which a widespread European bat, namely the common bent‐wing bat Miniopterus schreibersii, consumes crop‐damaging insects at a continental scale, and ii) tested whether its dietary niche is shaped by the extension and type of agricultural fields. We employed a dual‐primer DNA metabarcoding approach to characterize arthropod 16S and COI DNA sequences within bat faecal pellets collected across 16 Southern European localities, to first characterize the bat species’ dietary niche, second measure the incidence of agricultural pests across their ranges and third assess whether geographical dietary variation responds to climatic, landscape diversity, agriculture type and vegetation productivity factors. We detected 12 arthropod orders, among which lepidopterans were predominant. We identified >200 species, 44 of which are known to cause agricultural damage. Pest species were detected at all but one sampling site and in 94% of the analysed samples. Furthermore, the dietary diversity of M. schreibersii exhibited a negative linear relation with the area of intensive agricultural fields, thus suggesting crops restrict the dietary niche of bats to prey taxa associated with agricultural production within their foraging range. Overall, our results imply that M. schreibersii might be a valuable asset for biological pest suppression in a variety of agricultural productions and highlight the dynamic interplay between wildlife and agricultural systems.     

Effects of vitamin D metabolites on axolotl limb regeneration

Vitamin D is essential for normal metabolism of phosphorus and calcium, and differentiation of skeletal elements. 1,25 dihydroxyvitamin-D₃, the biologically active metabolite, acts as an induction/proliferation switch in various cell types and promotes chondrogenesis of chick limb bud mesenchymal cells. The function of vitamin D is mediated through its nuclear receptor, the vitamin D receptor (VDR). The proliferative actions of 1,25(OH)₂-D₃ on limb bud mesenchymal cells are similar to the ones produced by retinoids, such as all- trans retinoic acid (RA) or 9- cis retinoic acid (9- cis ). The retinoids have been shown to be compounds of extreme importance in the field of limb development and regeneration. In order to examine possible roles of vitamin D metabolites on limb regeneration, the effects of 1,25(OH)₂-D₃, 24,25(OH)₂-D₃ and KH1060 (a more potent metabolite) alone or in conjunction with all- trans RA or 9- cis RA on the regenerating axolotl limb. Vitamin D affects limb morphogenesis by generating abnormalities in skeletal elements. Synergism of vitamin D with retinoic acid in affecting pattern formation is suggested by the results.