Increased isolation of two Biosphere Reserves and surrounding protected areas (WAP ecological complex, West Africa)

Protected areas such as nature reserves have been found to be effective in preventing habitat destruction and protecting ecosystems within their borders. Recent studies however found extensive loss of tropical forest habitat around protected areas, vastly contributing to increase the levels of ecological isolation. Using high-resolution satellite data we investigated the isolation trend occurring in the W-Arly-Pendjari (WAP) ecological complex in West Africa. A land-cover change analysis was performed for the period 1984–2002: savanna vegetation extension and loss were derived within the complex and in a 30 km peripheral buffer. Sample regions in the buffer were also analysed using selected spatial indicators to quantify temporal trends in habitat fragmentation. Implications for change in relative capacity to conserve biodiversity were discussed through the calculation of the species richness capacity (SRC). More than 14.5% of savanna habitat was lost in the WAP peripheral areas, while 0.3% was converted inside the complex. The degree of fragmentation of remnant savanna habitat has also drastically increased. Despite the effectiveness of the park conservation programme, we found through the SRC approach that the WAP complex is decreasing its potential capacity to conserve species richness. This process is mainly due to the rapid and extended agricultural expansion taking place around the complex. A better understanding of the ecological dynamics occurring in the peripheral regions of reserves and the consideration of development needs are key variables to achieve conservation goals in protected areas.     

Comparative proteome profiling and functional analysis of chronic myelogenous leukemia cell lines

The aim of the present study was the molecular profiling of different Ph+ chronic myelogenous leukemia (CML) cell lines (LAMA84, K562, and KCL22) by a proteomic approach. By employing two-dimensional gel electrophoresis combined with mass spectrometry analysis, we have identified 191 protein spots corresponding to 142 different proteins. Among these, 63% were cancer-related proteins and 74% were described for the first time in leukemia cells. Multivariate analysis highlighted significant differences in the global proteomic profile of the three CML cell lines. In particular, the detailed analysis of 35 differentially expressed proteins revealed that LAMA84 cells preferentially expressed proteins associated with an invasive behavior, while K562 and KCL22 cells preferentially expressed proteins involved in drug resistance. These data demonstrate that these CML cell lines, although representing the same pathological phenotype, show characteristics in their protein expression profile that suggest different phenotypic leukemia subclasses. These data contribute a new potential characterization of the CML phenotype and may help to understand interpatient variability in the progression of disease and in the efficacy of a treatment.     

Development of sheep androgenetic embryos is boosted following transfer of male pronuclei into androgenetic hemizygotes

Androgenetic embryos are useful model for investigating the contribution of the paternal genome to embryonic development. Little work has been done with androgenetic embryo production in domestic animals. The aim of this study was the production of diploid androgenetic sheep embryos. In vitro matured sheep oocytes were enucleated and fertilized in vitro; parthenogenetic and normally fertilized embryos were also produced as a control. Fifteen hours after in vitro fertilization (IVF), presumptive zygotes were centrifuged and scored for the number of pronucleus. IVF, parthenogenetic, and androgenetic embryos (haploid, diploid, and triploid) were cultured in SOFaa medium with bovine serum albumin (BSA). The proportion of oocytes with polyspermic fertilization increased linearly with increasing sperm concentration. After IVF, there was no significant difference in early cleavage and morula formation rates between the groups, while there was a significant difference on blastocyst development between IVF, parthenogenetic, and androgenetic embryos, the last ones displaying poor developmental potential (IVF, parthenogenetic, and haploid, diploid, and triploid androgenetic embryos: 43%, 38%, 0%, 2%, and 2%, respectively). In order to boost androgenetic embryonic development, we produced diploid androgenetic embryos through pronuclear transfer. Single pronuclei were aspirated with a bevelled pipette from haploid or diploid embryos and transferred into the perivitelline space of other haploid embryos, and the zygotes were reconstructed by electrofusion. Fusion rates approached 100%. Pronuclear transfer significantly increased blastocyst development (IVF, parthenogenetic, androgenetic: Diploid into Haploid, and Haploid into Haploid: 42%, 42%, 19%, and 3%, respectively); intriguingly, the Haploid + Diploid group showed the highest development to blastocyst stage. The main findings of our study are: (1) sheep androgenetic embryos display poor developmental ability compared with IVF and parthenogenetic embryos; (2) diploid androgenetic embryos produced by pronuclear exchange developed in higher proportion to blastocyst stage, particularly in the Diploid-Haploid group. In conclusion, pronuclear transfer is an effective method to produce sheep androgenetic blastocysts.     

Structural characterization of transglutaminase-catalyzed cross-linking between glyceraldehyde 3-phosphate dehydrogenase and polyglutamine repeats

The accumulation of abnormal polyglutamine-containing protein aggregates within the cytosol and nuclei of affected neurons is a hallmark of the progressive neurodegenerative disorders caused by an elongated (CAG)(n) repeat in the genome. The polyglutamine domains are excellent substrates for the enzyme transglutaminase type 2 (tissue), resulting in the formation of cross-links with polypeptides containing lysyl groups. Enzymatic activity toward the Q(n) domains increases greatly upon lengthening of such Q(n) stretches (n > 40). Among the possible amine donors, the glycolytic enzyme glyceraldehyde-3-phosphate-dehydrogenase was shown to tightly bind several proteins involved in polyglutamine expansion diseases. Recently, the authors have shown that K191, K268, and K331, out of the 26 lysines present in glyceraldehyde-3-phosphate-dehydrogenase, are the reactive amine-donor sites forming cross-links with substance P, which bears the simplest Q(n) domain (n = 2). The present study reports that synthetic peptides of both pathological and nonpathological length (n = 43 and 17, respectively) form cross-links with the same K residues located in the C-terminal region of glyceraldehyde-3-phosphate-dehydrogenase. In addition, it is shown that extra K residues present in the C termini of glyceraldehyde-3-phosphate-dehydrogenase are susceptible to cross-linking in the presence of transglutaminase. The present results indicate a possible modulating effect of Q(n) stretches on tissue transglutaminase substrate specificity and mechanism of recognition.     

Peroxisome proliferator-activated receptor gamma ligands attenuate immunological symptoms of experimental allergic asthma

Asthma is characterized by a predominant T(H)2 type immune response to airborne allergens. Controlling T(H)2 cell function has been proposed as therapy for this disease. We show here that ligands for the nuclear receptor peroxisome proliferator activated receptor (PPAR)gamma significantly reduced the immunological symptoms of allergic asthma in a murine model of this disease. A PPARgamma ligand, 15-deoxy-delta(12,14)-prostaglandin J(2), significantly inhibited production of the T(H)2 type cytokine IL-5 from T cells activated in vitro. More importantly, in a murine model of allergic asthma, mice treated orally with ciglitazone, a potent synthetic PPARgamma ligand, had significantly reduced lung inflammation and mucous production following induction of allergic asthma. T cells from these ciglitazone treated mice also produced less IFNgamma, IL-4, and IL-2 upon rechallenge in vitro with the model allergen. Our results suggest that ligands for PPARgamma may be effective treatments for asthmatic patients.     

Methylation profile of P. lividus sea urchin genes during development

Methylation pattern has been studied in two genes of sea urchin Paracentrotus lividus using sodium bisulfite method to understand the possible role of DNA methylation during invertebrate development. Three regions of the gene for the hatching enzyme have been analyzed and all of them resulted unmethylated in embryos at different stages of development. Four CpG rich regions have been studied in the gene for DNA methyltransferase: upstream, upstream-exon1, intron 1 and exon 20. The upstream-exon 1 region is always unmethylated, while intron 1 and exon 20 are heavy methylated. Only the upstream fragment changed its pattern of methylation during development. For none of the studied regions the reported data show a general direct correlation between gene expression and methylation process during development.