Mapping of the mouse Tdgf1 gene and Tdgf pseudogenes

Teratocarcinoma-derived growth factor-1 (Tdgf1), a member of the ``EGF family' of growth factors, is expressed during mouse gastrulation in the forming mesoderm and later in the truncus arteriosus of the developing heart. In humans, TDGF1 is highly expressed in germ cell tumors and in colon and mammary carcinomas. In mouse, one gene (Tdgf1) and two pseudogenes (Tdgf1-ps1 and Tdgf1-ps2) have been isolated and characterized. Tdgf1 corresponds to the gene expressed in F9 teratocarcinoma cells. Tdgf1-ps1 and Tdgf1-ps2 are two intronless sequences with all the characteristics of retroposons. In the present paper, we assign the chromosomal location for Tdgf1, Tdgf1-ps1, and Tdgf1-ps2 sequences to Chromosomes (Chrs) 9, 16, and 17, respectively. Two previously described mouse mutants, scant hair (sch) and fur deficient (fd), map near the Tdgf1 gene. Analysis of their DNA coding region provided no evidence that Tdgf1 could be the responsible gene for these phenotypes. Finally, analysis of the DNA from several Mus musculus strains and from Mus spretus mice revealed a highly variable restriction pattern and the absence of the Tdgf1-ps1 genomic sequence from the Mus spretus genome. Received: 23 November 1996 / Accepted: 17 February 1997     

A correlation between BCL-2 modifying factor,p53 and livin gene expressions in cancer colon patients

Accumulating evidence has revealed that livin gene and BCL-2 modifying factor (BMF) gene are closely associated with the initiation and progression of colon carcinoma by activating or suppressing multiple malignant processes. Those genes that can detect colon - cancer are a promising approach for cancer screening and diagnosis. This study aimed to evaluate correlation between livin, BMF and p53 genes expression in colon cancer tissues of patients included in the study, and their relationship with clinicopathological features and survival outcome in those patients. In this study, 50 pathologically diagnosed early cancer colon patients included and their tissue biopsy with 50 matched adjacent normal tissue, and 50 adenoma tissue specimens were analyzed for livin gene and BMF gene expressions using real time PCR. The relationship of those genes expressions with clinicopathological features, tumor markers, Time to Progression and overall survival for those patients were correlated in cancer colon group. In this study, there was a significant a reciprocal relationship between over expression of livin gene and down regulation of BMF and p53 genes in colon cancer cells. Livin mRNA was significantly higher, while BMF and p53 mRNA were significantly lower in colorectal cancer tissue compared to benign and normal colon tissue specimens (P < 0.001), however, this finding was absent between colon adenomas and normal mucosa. There was a significant association between up regulation of livin and down regulation of BMF and p53 expressions with more aggressive tumor (advanced TNM stage), rapid progression with metastasis and decreased overall survival in cancer colon patients, hence these genes can serve as significant prognostic markers of poor outcome in colon cancer patients. This work highlights the role of livin, BMF and p53 genes in colorectal tumorigenesis and the applicability of using those genes as a diagnostic and prognostic markers in patients with colon carcinoma and as a good target for cancer colon treatment in the future.     

Biocides formulation of essential oils having antimicrobial activity

Essential oils of fennel, peppermint, caraway, eucalyptus, geranium and lemon were tested for their antimicrobial activities against some plant pathogenic micro-organisms (Fusarium oxysporum, Alternaria alternate, Penicilium italicum Penicilium digitatum and Botyritus cinerea). Essential oils of fennel, peppermint, caraway were selected as an active ingredient for the formulation of biocides due to their efficiency in controlling the tested micro-organisms. Successful emulsifiable concentrates (biocides) were prepared from these oils using different emulsifiers (Emulgator B.L.M. Tween20 and Tween80) and different fixed oils (sesame, olive, cotton and soybean oils). Physico-chemical properties of the formulated biocide (spontaneous emulsification, emulsion stability test, cold stability and heat stability tests as well as viscosity, surface tension and pH) were measured. The prepared biocides were ready to be tested for application in a future work as a safe pesticide against different pathogens.     

Embedding Aβ42 in Heterogeneous Membranes Depends on Cholesterol Asymmetries

Using a coarse-grained lipid and peptide model, we show that the free energy stabilization of amyloid-β in heterogeneous lipid membranes is predicted to have a dependence on asymmetric distributions of cholesterol compositions across the membrane leaflets. We find that a highly asymmetric cholesterol distribution that is depleted on the exofacial leaflet but enhanced on the cytofacial leaflet of the model lipid membrane thermodynamically favors membrane retention of a fully embedded Aβ peptide. However, in the case of cholesterol redistribution that increases concentration of cholesterol on the exofacial layer, typical of aging or Alzheimer’s disease, the free energy favors peptide extrusion of the highly reactive N-terminus into the extracellular space that may be vulnerable to aggregation, oligomerization, or deleterious oxidative reactivity.     

Metagenomic insights into strategies of carbon conservation and unusual sulfur biogeochemistry in a hypersaline Antarctic lake

Organic Lake is a shallow, marine-derived hypersaline lake in the Vestfold Hills, Antarctica that has the highest reported concentration of dimethylsulfide (DMS) in a natural body of water. To determine the composition and functional potential of the microbial community and learn about the unusual sulfur chemistry in Organic Lake, shotgun metagenomics was performed on size-fractionated samples collected along a depth profile. Eucaryal phytoflagellates were the main photosynthetic organisms. Bacteria were dominated by the globally distributed heterotrophic taxa Marinobacter, Roseovarius and Psychroflexus. The dominance of heterotrophic degradation, coupled with low fixation potential, indicates possible net carbon loss. However, abundant marker genes for aerobic anoxygenic phototrophy, sulfur oxidation, rhodopsins and CO oxidation were also linked to the dominant heterotrophic bacteria, and indicate the use of photo- and lithoheterotrophy as mechanisms for conserving organic carbon. Similarly, a high genetic potential for the recycling of nitrogen compounds likely functions to retain fixed nitrogen in the lake. Dimethylsulfoniopropionate (DMSP) lyase genes were abundant, indicating that DMSP is a significant carbon and energy source. Unlike marine environments, DMSP demethylases were less abundant, indicating that DMSP cleavage is the likely source of high DMS concentration. DMSP cleavage, carbon mixotrophy (photoheterotrophy and lithoheterotrophy) and nitrogen remineralization by dominant Organic Lake bacteria are potentially important adaptations to nutrient constraints. In particular, carbon mixotrophy relieves the extent of carbon oxidation for energy production, allowing more carbon to be used for biosynthetic processes. The study sheds light on how the microbial community has adapted to this unique Antarctic lake environment.     

Divergence with gene flow is driven by local adaptation to temperature and soil phosphorus concentration in teosinte subspecies (Zea mays parviglumis and Zea mays mexicana)

Patterns of genomic divergence between hybridizing taxa can be heterogeneous along the genome. Both differential introgression and local adaptation may contribute to this pattern. Here, we analysed two teosinte subspecies, Zea mays ssp. parviglumis and ssp. mexicana, to test whether their divergence has occurred in the face of gene flow and to infer which environmental variables have been important drivers of their ecological differentiation. We generated 9,780 DArTseqTM SNPs for 47 populations, and used an additional data set containing 33,454 MaizeSNP50 SNPs for 49 populations. With these data, we inferred features of demographic history and performed genome wide scans to determine the number of outlier SNPs associated with climate and soil variables. The two data sets indicate that divergence has occurred or been maintained despite continuous gene flow and/or secondary contact. Most of the significant SNP associations were to temperature and to phosphorus concentration in the soil. A large proportion of these candidate SNPs were located in regions of high differentiation that had been identified previously as putative inversions. We therefore propose that genomic differentiation in teosintes has occurred by a process of adaptive divergence, with putative inversions contributing to reduced gene flow between locally adapted populations.     

Stimulation by n6-cyclopentyladenosine of A1 adenosine receptors, coupled to galphai2 protein subunit, has a capacitative effect on human spermatozoa

The effects of selective A(1) receptor agonist on human spermatozoa were examined to verify physiological responses and to investigate the signal transduction pathway. N6-Cyclopentyladenosine on uncapacitated spermatozoa did not induce spontaneous acrosome reaction after 5 h capacitation, whereas the number of capacitated spermatozoa, assessed by lysophosphatidylcholine-induced acrosome reaction with Pisum sativum agglutinin staining, was significantly increased. N6-Cyclopentyladenosine was also added to capacitated human spermatozoa to find out whether the agonist could induce the acrosome reaction. Results, although statistically significant, could not be considered biologically significant. A1-Mediated capacitation was followed by the increase of tyrosine phosphorylation of a protein subset ranging between M(r) = 200 000 and 30 000. Stimulation of A1 receptor with the selective agonist elicited an agonist-induced inositol phospholipid hydrolysis leading to a transient rise of inositol triphosphate (IP3). This increase was not induced by A(1) receptor antagonist and was blocked by phospholipase C inhibitor. Coimmunoprecipitation experiments showed that the A(1) receptor is coupled to Galphai2 subunit suggesting that the activation of phospholipase C is mediated by betagamma subunits. In conclusion, the A(1) adenosine receptor in human spermatozoa is coupled to Galphai2, signals via IP3, and affects the capacitative status of ejaculated spermatozoa.     

Membrane-anchorage of Cripto protein by glycosylphosphatidylinositol and its distribution during early mouse development

cripto is the original member of the family of EGF-CFC genes, recently recognized as novel extracellular factors essential for vertebrate development. During the early stages of mouse gastrulation, cripto mRNA is detected in mesodermal cells; later, cripto mRNA is detected only in the truncus arteriosus of the developing heart. Here we describe the in vivo distribution of Cripto protein throughout mouse embryo development and show that cripto mRNA and protein colocalize. By means of immunofluorescence analysis and biochemical characterization, we show that Cripto is a membrane-bound protein anchored to the lipid bilayer by a glycosylphosphatidylinositol (GPI) moiety. We suggest that presentation of Cripto on the cell surface via a GPI-linkage is important in determining the spatial specificity of cell–cell interactions that play a critical role in the early patterning of the embryo.