Caveolin-1 overexpression correlates with tumour progression markers in pancreatic ductal adenocarcinoma

The assessment of caveolin-1 (Cav-1) as a marker of tumor aggressiveness in pancreatic ductal adenocarcinoma (PDAC). In this study, we examined the expression of Cav-1 in 34 human PDAC tissue samples and the associated peritumoral tissues by immunohistochemistry and western blot. Additionally, we correlated Cav-1 expression with other tissue (Ki-67, p53) and serum (CA 19-9) tumor markers. In the tumor-derived tissue, both tumor cells and blood vessels expressed Cav-1. In contrast, in peritumoral tissue, Cav-1 expression was confined mainly to blood vessels and was only occasionally expressed in ductal or parenchymal cells. Western blot analysis confirmed the overexpression of Cav-1 in pancreatic tumors compared with peritumoral tissue. Cav-1 expression in tumor tissues was correlated with both the Ki-67 LI (r = 0.95, P < 0.0001) and p53 expression (χ2 = 9.91, P < 0.005). Overexpression of Cav-1 was associated with tumor size, grade and stage and Cav-1 expression in tumors was correlated with an increased serum level of CA 19-9 (r = 0.795, P < 0.001). Based on the results of this study, the inclusion of Cav-1 in a putative panel of biomarkers predicting pancreatic cancer aggressiveness is warranted.     

Hydrophobic and Basic Domains Target Proteins to Lipid Droplets

In recent years, progress in the study of the lateral organization of the plasma membrane has led to the proposal that mammalian cells use two different organelles to store lipids: intracellular lipid droplets (LDs) and plasma membrane caveolae. Experimental evidence suggests that caveolin (CAV) may act as a sensitive lipid-organizing molecule that physically connects these two lipid-storing organelles. Here, we determine the sequences necessary for efficient sorting of CAV to LDs. We show that targeting is a process cooperatively mediated by two motifs. CAV's central hydrophobic domain (Hyd) anchors CAV to the endoplasmic reticulum (ER). Next, positively charged sequences (Pos-Seqs) mediate sorting of CAVs into LDs. Our findings were confirmed by identifying an equivalent, non-conserved but functionally interchangeable Pos-Seq in ALDI, a bona fide LD-resident protein. Using this information, we were able to retarget a cytosolic protein and convert it to an LD-resident protein. Further studies suggest three requirements for targeting via this mechanism: the positive charge of the Pos-Seq, physical proximity between Pos-Seq and Hyd and a precise spatial orientation between both motifs. The study uncovers remarkable similarities with the signals that target proteins to the membrane of mitochondria and peroxisomes     

Identification of paraoxonase 3 gene (PON3) missense mutations in a population of southern Italy

PON gene family includes at least three members termed PON1, PON2 and PON3, and it is mapped on human chromosome 7q21-q22. PON1 and PON3 gene products are constituents of high density lipoprotein (HDL) and have many enzymatic properties and antioxidant activity. PONs are proposed to participate in the prevention of low density lipoprotein (LDL) oxidation. PON1 and PON2 genes have missense polymorphisms, but, to date, no missense variants are reported in PON3 gene. In this work we explored the existence of genetic variants within the PON3 coding sequences. Five point mutations were identified by direct sequencing of genomic DNA derived from 250 randomly selected DNA samples of 1143 blood donors living in southern Italy. Three were silent mutations, while two were missense mutations that give rise to amino acid substitutions at positions 311 (S>T) and 324 (G>D). The missense variations in the DNA of the 1143 samples had frequencies of 0.22% (5 out of 2286 alleles) for the S311T mutation, and 0.57% (13 out of 2286 alleles) for the G324D mutation. The effect of these variants on the metabolic activity of paraoxonase 3 remains to be further evaluated.     

Effect of applied and internal hormones on vitrification and apical necrosis of different plants cultured in vitro

Development of vitrification and apical necrosis was followed in Camellia sinensis, Gerbera jamesonii, Malus domestica and hybrid Populus tremula x P. alba shoots cultured in vitro on Murashige & Skoog (MS) medium with different concentrations of growth regulators. High humidity in the culture vessels and excess of BA in the medium were found to be the major factors influencing vitrification. Lack of exogenous cytokinin in the medium during successive subcultures induced apical necrosis in poor-rooting species (Malus domestica, Camellia sinensis). The level of internal phytohormones (ABA, IAA, IPA, 2iP, Z, ZR) was determined in the apple shoots by means of ELISA. The content of internal cytokinins in the vitrified apple shoots was several times greater than in normal ones, which supports the hypothesis that excess of cytokinins, inducing rapid divisions of cells in meristems in the atmosphere with high humidity, is responsible for vitrification. Apical necrosis of the plantlets that appeared after cultivation on cytokinin-free medium is the result of deficiency in endogenous hormones in apple shoots and this being confirmed by analysis of endogenous hormones in apple shoots.Abbreviations BA benzyladenine - BHT butylated hydroxy-toluene - ABA abscisic acid - IAA indole-3-acetic acid - ELISA enzyme-linked immunosorbent assay - IPA isopentenyladenosine - 2iP isopentenyladenine - NAA naphthyl-3-acetic acid - TBS trishydroxymethylaminomethane buffered saline - TLC thin layer chromatography - Z zeatin - ZR zeatin riboside     

Archaeal and bacterial diversity in five different hydrothermal ponds in the Copahue region in Argentina

Copahue is an acidic geothermal volcanic region in the northwest corner of Neuquén Province, Argentina. In the area, there are various ponds, pools and hot springs with different temperatures, pH values and levels of anthropogenic influence. In this study, the prokaryotic biodiversity of five representative ponds was studied by using two complementary molecular ecology techniques: phylogenetic analysis of 16S rRNA bacterial and archaeal genes and FISH (or CARD-FISH) for quantitative estimation of biodiversity. The results, supported by multivariate statistical analysis, showed that the biodiversity in Copahue ponds seemed to be determined by temperature. High temperature ponds were dominated by archaea, mainly apparently novel representatives from the orders Sulfolobales and Thermoplasmatales that had no close cultivated relatives. By contrast, moderate temperature ponds were colonised by well-characterised sulphur-oxidising bacteria related to acidic environments, such as other geothermal sites or acid mine drainage, and archaea were absent. By combining the biodiversity results from this study and the reported physicochemical features of Copahue, a preliminary model of the possible biogeochemical interaction was outlined for moderate and high temperature ponds.     

Heterostyly accelerates diversification via reduced extinction in primroses

The exceptional species diversity of flowering plants, exceeding that of their sister group more than 250-fold, is especially evident in floral innovations, interactions with pollinators and sexual systems. Multiple theories, emphasizing flower–pollinator interactions, genetic effects of mating systems or high evolvability, predict that floral evolution profoundly affects angiosperm diversification. However, consequences for speciation and extinction dynamics remain poorly understood. Here, we investigate trajectories of species diversification focusing on heterostyly, a remarkable floral syndrome where outcrossing is enforced via cross-compatible floral morphs differing in placement of their respective sexual organs. Heterostyly evolved at least 20 times independently in angiosperms. Using Darwin''s model for heterostyly, the primrose family, we show that heterostyly accelerates species diversification via decreasing extinction rates rather than increasing speciation rates, probably owing to avoidance of the negative genetic effects of selfing. However, impact of heterostyly appears to differ over short and long evolutionary time-scales: the accelerating effect of heterostyly on lineage diversification is manifest only over long evolutionary time-scales, whereas recent losses of heterostyly may prompt ephemeral bursts of speciation. Our results suggest that temporal or clade-specific conditions may ultimately determine the net effects of specific traits on patterns of species diversification.     

Draft Genome Sequence of the Hydrocarbon-Degrading and Emulsan-Producing Strain Acinetobacter venetianus RAG-1T

We report the draft genome sequence of Acinetobacter venetianus strain RAG-1(T), which is able to degrade hydrocarbons and to synthesize a powerful biosurfactant (emulsan) that can be employed for oil removal and as an adjuvant for vaccine delivery. The genome sequence of A. venetianus RAG-1(T) might be useful for bioremediation and/or clinical purposes.     

Sponge-associated microbial Antarctic communities exhibiting antimicrobial activity against Burkholderia cepacia complex bacteria

The aerobic heterotrophic bacterial communities isolated from three different Antarctic sponge species were analyzed for their ability to produce antimicrobial compounds active toward Cystic Fibrosis opportunistic pathogens belonging to the Burkholderia cepacia complex (Bcc). The phylogenetic analysis performed on the 16S rRNA genes affiliated the 140 bacterial strains analyzed to 15 genera. Just three of them (Psychrobacter, Pseudoalteromonas and Arthrobacter) were shared by the three sponges. The further Random Amplified Polymorphic DNA analysis allowed to demonstrate that microbial communities are highly sponge-specific and a very low degree of genus/species/strain sharing was detected. Data obtained revealed that most of these sponge-associated Antarctic bacteria and belonging to different genera were able to completely inhibit the growth of bacteria belonging to the Bcc. On the other hand, the same Antarctic strains did not have any effect on the growth of other pathogenic bacteria, strongly suggesting that the inhibition is specific for Bcc bacteria. Moreover, the antimicrobial compounds synthesized by the most active Antarctic bacteria are very likely Volatile Organic Compounds (VOCs), a finding that was confirmed by the SPME-GC-MS technique, which revealed the production of a large set of VOCs by a representative set of Antarctic bacteria. The synthesis of these VOCs appeared to be related neither to the presence of pks genes nor the presence of plasmid molecules. The whole body of data obtained in this work indicates that sponge-associated bacteria represent an untapped source for the identification of new antimicrobial compounds and are paving the way for the discovery of new drugs that can be efficiently and successfully used for the treatment of CF infections.