Linkage analysis and allelic imbalance in human breast cancer kindreds using microsatellite markers from the short arm of chromosome 3

Eight Icelandic breast cancer kindreds were subjected to linkage analyses with respect to 28 microsatellite loci dispersed along the short arm of chromosome 3. Breast tumors derived from these kindreds were concurrently scored for allelic imbalance with ten of the markers. Linkage to most markers could be excluded on the basis of negative LOD scores and haplotype analyses, although some moderately positive LOD scores resulted. A high frequency of imbalance in the familial tumors was seen with two of the markers in comparison with results obtained from sporadic material. The highest frequency (68%) of imbalance was detected with the marker D3S1217, which is located on 3p14.2-p14.1. Imbalance at the D3S1211 locus, which is more telomeric (3p24.2-p22), was not significantly elevated in the familial tumors. We suggest that the genetic defect responsible for breast cancer susceptibility in these families either promotes instability in the 3p14.2-p14.1 region or enhances the selective advantage of such changes.     

Quantifying Cancer Absolute Risk and Cancer Mortality in the Presence of Competing Events after a Myotonic Dystrophy Diagnosis

Recent studies show that patients with myotonic dystrophy (DM) have an increased risk of specific malignancies, but estimates of absolute cancer risk accounting for competing events are lacking. Using the Swedish Patient Registry, we identified 1,081 patients with an inpatient and/or outpatient diagnosis of DM between 1987 and 2007. Date and cause of death and date of cancer diagnosis were extracted from the Swedish Cause of Death and Cancer Registries. We calculated non-parametric estimates of absolute cancer risk and cancer mortality accounting for the high non-cancer competing mortality associated with DM. Absolute cancer risk after DM diagnosis was 1.6% (95% CI=0.4-4%), 5% (95% CI=3-9%) and 9% (95% CI=6-13%) at ages 40, 50 and 60 years, respectively. Females had a higher absolute risk of all cancers combined than males: 9% (95% CI=4-14), and 13% (95% CI=9-20) vs. 2% (95%CI= 0.7-6) and 4% (95%CI=2-8) by ages 50 and 60 years, respectively) and developed cancer at younger ages (median age =51 years, range=22-74 vs. 57, range=43-84, respectively, p=0.02). Cancer deaths accounted for 10% of all deaths, with an absolute cancer mortality risk of 2% (95%CI=1-4.5%), 4% (95%CI=2-6%), and 6% (95%CI=4-9%) by ages 50, 60, and 70 years, respectively. No gender difference in cancer-specific mortality was observed (p=0.6). In conclusion, cancer significantly contributes to morbidity and mortality in DM patients, even after accounting for high competing DM mortality from non-neoplastic causes. It is important to apply population-appropriate, validated cancer screening strategies in DM patients.     

Effect of arbuscular mycorrhizal fungi on phytoextraction by corn (Zea mays) of lead-contaminated soil

The role of arbuscular mycorrhizal fungi (AMF) in lead (Pb) uptake by corn (Zea mays) grown in soil supplemented with Pb was examined. Plants were subjected to four Pb levels: 0 (control); 10 (low); 100 (medium); and 500 mg L(-1) (high). At each Pb level, plants were grown in soil without and with fungicide (benomyl) (20 mg kg(-1)) to suppress AMF activity. Benomyl significantly reduced AMF colonization at high. medium, and zero Pb exposures. Benomyl application resulted in significantly lower concentrations of phosphorus in leaves at low and medium Pb exposures. The benomyl-treated plants had higher Pb and manganese concentrations in leaves than plants not treated with benomyl. In addition, benomyl-treated plants had generally lower concentrations of zinc and copper in leaves than plants not treated with benomyl. These results suggest that the role of AMF in heavy metal uptake is metal specific. Based on this work, the use of benomyl on soils contaminated with Pb can be recommended in phytoextraction.     

Does Breeding Site Fidelity Drive Phenotypic and Genetic Sub-Structuring of a Population of Arctic Charr?

There is now increasing acceptance that divergence of phenotypic traits, and the genetic structuring that underlie such divergence, can occur in sympatry. Here we report the serendipitous discovery of a sympatric polymorphism in the upper Forth catchment, Scotland, in a species for which high levels of phenotypic variation have been reported previously, the Arctic charr, Salvelinus alpinus. Attempting to determine the proximate mechanisms through which this pattern of phenotypic variation is maintained, we examine the use of the available feeding resource and the genotypic and phenotypic structure of charr in this system. We show clear differences in head morphology between charr from three very closely connected lakes with no barrier to movement (Lochs Doine, Voil and Lubnaig) and also differences in muscle stable isotope signatures and in stomach contents. There were significant differences at 6 microsatelite loci (between Lubnaig and the other two lochs) and very low estimates of effective migration between populations. We conclude that, despite living in effective sympatry, strong genetic and phenotypic sub-structuring is likely maintained by very high levels of site fidelity, especially during spawning, resulting in functional allopatric divergence of phenotype.     

Duplicated sequence motif in the long terminal repeat of maedi-visna virus extends cell tropism and is associated with neurovirulence

Maedi-visna virus (MVV) is a lentivirus of sheep causing chronic inflammatory disease of the lungs (maedi) and the nervous system (visna). We have previously shown that a duplicated sequence in the long terminal repeat (LTR) of MVV is a determinant of cell tropism. Here, we demonstrate that deletion of a CAAAT sequence from either one of the repeats resulted in poor virus growth in sheep choroid plexus cells. A duplication in the LTR encompassing the CAAAT sequence was found in four neurological field cases that were sequenced, but no duplication was present in the LTRs from seven maedi cases; one maedi isolate was mixed. These results indicate that the duplication in the LTR is associated with neurovirulence.     

Glutamine-Fructose-6-Phosphate Transaminase 2 (GFPT2) Is Upregulated in Breast Epithelial–Mesenchymal Transition and Responds to Oxidative Stress

Breast cancer cells that have undergone partial epithelial–mesenchymal transition (EMT) are believed to be more invasive than cells that have completed EMT. To study metabolic reprogramming in different mesenchymal states, we analyzed protein expression following EMT in the breast epithelial cell model D492 with single-shot LFQ supported by a SILAC proteomics approach. The D492 EMT cell model contains three cell lines: the epithelial D492 cells, the mesenchymal D492M cells, and a partial mesenchymal, tumorigenic variant of D492 that overexpresses the oncogene HER2. The analysis classified the D492 and D492M cells as basal-like and D492HER2 as claudin-low. Comparative analysis of D492 and D492M to tumorigenic D492HER2 differentiated metabolic markers of migration from those of invasion. Glutamine-fructose-6-phosphate transaminase 2 (GFPT2) was one of the top dysregulated enzymes in D492HER2. Gene expression analysis of the cancer genome atlas showed that GFPT2 expression was a characteristic of claudin-low breast cancer. siRNA-mediated knockdown of GFPT2 influenced the EMT marker vimentin and both cell growth and invasion in vitro and was accompanied by lowered metabolic flux through the hexosamine biosynthesis pathway (HBP). Knockdown of GFPT2 decreased cystathionine and sulfide:quinone oxidoreductase (SQOR) in the transsulfuration pathway that regulates H₂S production and mitochondrial homeostasis. Moreover, GFPT2 was within the regulation network of insulin and EGF, and its expression was regulated by reduced glutathione (GSH) and suppressed by the oxidative stress regulator GSK3-β. Our results demonstrate that GFPT2 controls growth and invasion in the D492 EMT model, is a marker for oxidative stress, and associated with poor prognosis in claudin-low breast cancer.     

Density,length distribution,and diet of age-0 arctic charrSalvelinus alpinus in the surf zone of Thingvallavatn,Iceland

Synopsis Population densities of age-0 arctic chaff in the surf zone averaged 1.83 and 4.70 fish m^-2 in August 1984 and June 1985, respectively. Length variation of the littoral fish was low in early summer, increasing in late summer and autumn. Newly emerged charr, ∼ 20 mm long, appeared in the stony shallow water zone during both May and June. From length variation and variation in mouth position of the young charr, it is concluded that at least two of the four chaff morphs in the lake are present in the surf zone during spring and summer. In August, some of the larger age-0 charr had moved out from the surf zone, into the pelagic and the deeper epibenthic waters. The food of young littoral charr was dominated by large chironomid larvae (instar 3 and 4) and pupae Contribution from the Thingvallavatn project     

Induced Phytoextraction of Lead Through Chemical Manipulation of Switchgrass and Corn; Role of Iron Supplement

The effects of combined chemical application of benomyl, ethylenedianinetetraacetate (EDTA), and iron (Fe) (foliar and root) on lead (Pb) phytoextraction by switchgrass (Panicum virgatum) and corn (Zea mays) was examined. Switchgrass was grown in Pb-contaminated urban topsoil with the following treatments: (C) Control, (B) benomyl, (E) EDTA, (F) foliar-Fe, (BE) benomyl + EDTA, (BF) benomyl + foliar-Fe, (FE) foliar-Fe + EDTA, (BFE) benomyl + foliar-Fe + EDTA. Corn was grown in sand-culture supplemented with Pb (500 mg kg^?1) with the following treatments: (C) control, (B) benomyl, (E) EDTA, (F) root-Fe, (BE) benomyl + EDTA, (BF) benomyl + root-Fe, (FE) root-iron + EDTA, and, (BFE) benomyl + root-Fe + EDTA. All treatments were replicated three times and pots were arranged in a completely randomized design. Plants were analyzed for element concentration (Fe, Zn, P, and Pb) using either inductively coupled plasma (argon) atomic emission spectroscopy (ICP-AES) or graphite furnace atomic absorption spectrometer. Iron supplementation (foliar and root) affected Pb-translocation in plants. Foliar-Fe treatment increased translocation ratio of Pb (TF-Pb) significantly compared to other treatments with the exception of plants treated with benomyl and BF. Root-Fe treatment in combination with EDTA (FE) increased TF-Pb significantly compared to other treatments. Phytoextraction was improved by the combined chemical application; plants treated with BFE treatment increased Pb-total-phytoextraction by 424% compared to Control plants.