The functionally elusive RabI chromosome configuration directly regulates nuclear membrane remodeling at mitotic onset

Despite its ubiquity in interphase eukaryotic nuclei, the functional significance of the RabI configuration, in which interphase centromeres are clustered at the nuclear envelope (NE) near the centrosome and telomeres localize at the opposite end of the nucleus, has remained mysterious. In a broad variety of organisms, including Schizosaccharomyces pombe, the RabI configuration is maintained throughout mitotic interphase. The fission yeast linker of nucleoskeleton and cytoskeleton (LINC) complex mediates this centromere association. The functional significance of centromere positioning during interphase has been recently revealed using a conditionally inactivated LINC allele that maintains LINC stability but releases interphase centromere-LINC contacts. Remarkably, this interphase release abolishes mitotic spindle formation. Here, we confirm these observations using an alternative strategy to explore the role of centromere-NE association without modifying the LINC complex. We analyze spindle dynamics in cells lacking Csi1, a stabilizer of centromere-LINC associations, and Lem2, a NE protein harboring lamin interacting domains. We recapitulate these observations and their implications for the functional significance of centromere positioning for cell cycle progression in fission yeast and most likely, a wide range of eukaryotes.     

Effects of adults body size and larvae diet on the fecundity and percent fertility of eggs laid by Xylotrechus arvicola (Coleoptera: Cerambycidae) females,insect pest in Spanish vineyards

Xylotrechus arvicola is a pest of grape in some vine‐producing regions of the Iberian Peninsula. Biological parameters and relationships (fecundity and percent fertility of eggs in relationship to body size) of females obtained in the laboratory and captured in vineyards were studied. In laboratory conditions, the mean developmental time of larvae ranged from 384 to 392 days and pupal stage varied between 12 to 14 days. Body size (BS) of X. arvicola females was significantly bigger than males. Fecundity was greater in the laboratory (147 eggs) than in the field (50 eggs) females, but the percent fertility of the laboratory eggs was lower (16 eggs). Laboratory females showed a bigger relationship between the production of eggs and BS than females captured in vineyards. Wild females (PDO Ribera del Duero and Tierra de León) had a positive relationship between the percent fertility of eggs and the BS. No correlation between the percent fertility of eggs and the BS was displayed by females captured in PDO Toro, but these females had a higher percent fertility (53 eggs) than the others PDO's. These biological parameters and relationships studied suggest that the artificial diet may lack certain essential nutrients that vine varieties can provide that favor the fertility of eggs. This explains why wild females have the potential to become a problem pest in the Tempranillo grape variety, with bilateral cordon and bush vines training systems that have the highest incidence of this cerambycid.     

Thiol redox proteomics seen with fluorescent eyes: the detection of cysteine oxidative modifications by fluorescence derivatization and 2-DE

There is increasing evidence that several reversible oxidative post-translational modifications of protein cysteines participate in cell signalling. Specific proteomic techniques are required to identify these modifications and to study their regulation in different cell processes, that are collectively known as thiol redox proteomics. Recently, fluorescence derivatization methods have been developed that enable these post-translational modifications to be studied using proteomic workflows based on two-dimensional electrophoresis, which is a relatively accessible and affordable technique. As well as enabling a large number of samples to be processed, two-dimensional electrophoresis has the advantage that it does not rely on the intensive use of mass spectrometers. This methodology allows to "visualise" redox changes in a broad context and, although identification of the modified residues is not so straightforward, complementary derivatization can overcome this drawback. Here we review the different derivatization strategies that have been employed in these studies, comparing their advantages and potential limitations. We also review the applications and results obtained, with particular emphasis on those involving (patho)physiological stimuli, thereby showing the potential of these techniques to study the thiol redox proteome.     

Comparison between the complete mtDNA sequences of the blue and the fin whale,two species that can hybridize in nature

The sequence of the mitochondrial DNA (mtDNA) molecule of the blue whale (Balaenoptera musculus) was determined. The molecule is 16,402 by long and its organization conforms with that of other eutherian mammals. The molecule was compared with the mtDNA of the congeneric fin whale (B. physalus). It was recently documented that the two species can hybridize and that male offspring are infertile whereas female offspring may be fertile. The present comparison made it possible to determine the degree of mtDNA difference that occurs between two species that are not completely separated by hybridization incompatibility. The difference between the complete mtDNA sequences was 7.4%. Lengths of peptide coding genes were the same in both species. Except for a small portion of the control region, disruption in alignment was usually limited to insertion/deletion of a single nucleotide. Nucleotide differences between peptide coding genes ranged from 7.1 to 10.5%, and difference at the inferred amino acid level was 0.0–7.9%. In the rRNA genes the mean transition difference was 3.8%. This figure is similar in degree to the difference (3.4%) between the 12S rRNA gene of humans and the chimpanzee. The mtDNA differences between the two whale species, involving both peptide coding and rRNA genes, suggest an evolutionary separation of 5 million years. Although hybridization between more distantly related mammalian species may not be excluded, it is probable that the blue and fin whales are nearly as different in their mtDNA sequences as hybridizing mammal species may be. Correspondence to: Ú. Árnason     

Influence of the geometry around the manganese ion on the peroxidase and catalase activities of Mn(III)-Schiff base complexes

The peroxidase and catalase activities of eighteen manganese-Schiff base complexes have been studied. A correlation between the structure of the complexes and their catalytic activity is discussed on the basis of the variety of systems studied. Complexes 1-18 have the general formulae [MnLⁿ(D)₂](X)(H₂O/CH₃OH)_m, where Lⁿ = L¹-L¹³; D = H₂O, CH₃OH or Cl; m = 0-2.5 and X = NO₃⁻, Cl⁻, ClO₄⁻, CH₃COO⁻, C₂H₅COO⁻ or C₅H₁₁COO⁻. The dianionic tetradentate Schiff base ligands H₂Lⁿ are the result of the condensation of different substituted (OMe-, OEt-, Br-, Cl-) hydroxybenzaldehyde with diverse diamines (1,2-diaminoethane for H₂L¹-H₂L²; 1,2-diamino-2-methylethane for H₂L³-H₂L⁴; 1,2-diamino-2,2-dimethylethane for H₂L⁵; 1,2-diphenylenediamine for H₂L⁶-H₂L⁷; 1,3-diaminopropane for H₂L⁸-H₂L¹¹; 1,3-diamino-2,2-dimethylpropane for H₂L¹²-H₂L¹³). The new Mn(III) complexes [MnL¹(H₂O)Cl](H₂O)_2.5 (2), [MnL²(H₂O)₂](NO₃)(H₂O) (4), [MnL⁶(H₂O)₂][MnL⁶(CH₃OH)(H₂O)](NO₃)₂(CH₃OH) (8), [MnL⁶(H₂O)(OAc)](H₂O) (9) and [MnL⁷(H₂O)₂](NO₃)(CH₃OH)₂ (12) were isolated and characterised by elemental analysis, magnetic susceptibility and conductivity measurements, redox studies, ESI spectrometry and UV, IR, paramagnetic ¹H NMR, and EPR spectroscopies. X-ray crystallographic studies of these complexes and of the ligand H₂L⁶ are also reported. The crystal structures of the rest of the complexes have been previously published and herein we have only revised their study by those techniques still not reported (EPR and ¹H NMR for some of these compounds) and which help to establish their structures in solution. Complexes 1-12 behave as more efficient mimics of peroxidase or catalase in contrast with 13-18. The analysis between the catalytic activity and the structure of the compounds emphasises the significance of the existence of a vacant or a labile position in the coordination sphere of the catalyst.     

P2RY1/ALK3-Expressing Cells within the Adult Human Exocrine Pancreas Are BMP-7 Expandable and Exhibit Progenitor-like Characteristics

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Monomer composition and sequence of sodium alginate extracted at pilot plant scale from three commercially important seaweeds from Mexico

The marine waters of the Baja California peninsula (Mexico) are a rich source of brown seaweeds with a great potential for exploitation. For that reason, Sargassum sinicola, Eisenia arborea, and Macrocystis pyrifera collected from different locations were subjected to extraction of sodium alginate using a pilot-plant scale process developed in our facilities. The composition and sequence parameters of the recovered alginate were studied by infrared and nuclear magnetic resonance spectroscopy. The spectral analysis of the products revealed that sodium alginate from S. sinicola contains a greater proportion of guluronate monomers (64%) than that from E. arborea (48%), and M. pyrifera (38%). Computation of the frequencies of diads and triads indicated that the alginate from S. sinicola was constructed by intercalated guluronate-blocks of 14 residues in length. In contrast, the length of the G-block in the alginates from E. arborea and M. pyrifera were 7 and 4 residues, respectively. The results show that S. sinicola, E. arborea, and M. pyrifera are sources of sodium alginate with different mannuronate/guluronate ratios, as well as a varied building-block length. In consequence, aqueous dispersions of sodium alginate from the three studied species are expected to exhibit different physical properties.     

Assessment of algorithms for high throughput detection of genomic copy number variation in oligonucleotide microarray data

Background

Genomic deletions and duplications are important in the pathogenesis of diseases, such as cancer and mental retardation, and have recently been shown to occur frequently in unaffected individuals as polymorphisms. Affymetrix GeneChip whole genome sampling analysis (WGSA) combined with 100 K single nucleotide polymorphism (SNP) genotyping arrays is one of several microarray-based approaches that are now being used to detect such structural genomic changes. The popularity of this technology and its associated open source data format have resulted in the development of an increasing number of software packages for the analysis of copy number changes using these SNP arrays.

Results

We evaluated four publicly available software packages for high throughput copy number analysis using synthetic and empirical 100 K SNP array data sets, the latter obtained from 107 mental retardation (MR) patients and their unaffected parents and siblings. We evaluated the software with regards to overall suitability for high-throughput 100 K SNP array data analysis, as well as effectiveness of normalization, scaling with various reference sets and feature extraction, as well as true and false positive rates of genomic copy number variant (CNV) detection.

Conclusion

We observed considerable variation among the numbers and types of candidate CNVs detected by different analysis approaches, and found that multiple programs were needed to find all real aberrations in our test set. The frequency of false positive deletions was substantial, but could be greatly reduced by using the SNP genotype information to confirm loss of heterozygosity.     

BMP9 Is a Proliferative and Survival Factor for Human Hepatocellular Carcinoma Cells

TGF-β family members play a relevant role in tumorigenic processes, including hepatocellular carcinoma (HCC), but a specific implication of the Bone Morphogenetic Protein (BMP) subfamily is still unknown. Although originally isolated from fetal liver, little is known about BMP9, a BMP family member, and its role in liver physiology and pathology. Our results show that BMP9 promotes growth in HCC cells, but not in immortalized human hepatocytes. In the liver cancer cell line HepG2, BMP9 triggers Smad1,5,8 phosphorylation and inhibitor of DNA binding 1 (Id1) expression up- regulation. Importantly, by using chemical inhibitors, ligand trap and gene silencing approaches we demonstrate that HepG2 cells autocrinely produce BMP9 that supports their proliferation and anchorage independent growth. Additionally, our data reveal that in HepG2 cells BMP9 triggers cell cycle progression, and strikingly, completely abolishes the increase in the percentage of apoptotic cells induced by long-term incubation in low serum. Collectively, our data unveil a dual role for BMP9, both promoting a proliferative response and exerting a remarkable anti-apoptotic function in HepG2 cells, which result in a robust BMP9 effect on liver cancer cell growth. Finally, we show that BMP9 expression is increased in 40% of human HCC tissues compared with normal human liver as revealed by immunohistochemistry analysis, suggesting that BMP9 signaling may be relevant during hepatocarcinogenesis in vivo. Our findings provide new clues for a better understanding of BMPs contribution, and in particular BMP9, in HCC pathogenesis that may result in the development of effective and targeted therapeutic interventions.     

Towards the top: niche expansion of Taraxacum officinale and Ulex europaeus in mountain regions of South America

In the current context of ongoing global change, the understanding of how the niches of invasive species may change between different geographical areas or time periods is extremely important for the early detection and control of future invasions. We evaluated the effect of climate and non‐climate variables and the sensitivity to various spatial resolutions (i.e. 1 and 20 km) on niche changes during the invasion of Taraxacum officinale and Ulex europaeus in South America. We estimated niche changes using a combination of principal components analyses (PCA) and reciprocal Ecological Niche Modelling (rENM). We further investigated future invasion dynamics under a severe warming scenario for 2050 to unravel the role of niche shifts in the future potential distribution of the species. We observed a clear niche expansion for both species in South America towards higher temperature, precipitation and radiation relative to their native ranges. In contrast, the set of environmental conditions only occupied in the native ranges (i.e. niche unfilling) were less relevant. The magnitude of the niche shifts did not depend on the resolution of the variables. Models calibrated with occurrences from native range predicted large suitable areas in South America (outside of the Andes range) where T. officinale and U. europaeus are currently absent. Additionally, both species could increase their potential distributions by 2050, mostly in the southern part of the continent. In addition, the niche unfilling suggests high potential to invade additional regions in the future, which is extremely relevant considering the current impact of these species in the Southern Hemisphere. These findings confirm that invasive species can occupy new niches that are not predictable from knowledge based only on climate variables or information from the native range.