No Evidence that Extended Tracts of Homozygosity are Associated with Alzheimer’s Disease.

We sought to investigate the contribution of extended runs of homozygosity in a genome-wide association dataset of 1,955 Alzheimer's disease cases and 955 elderly screened controls genotyped for 529,205 autosomal single nucleotide polymorphisms. Tracts of homozygosity may mark regions inherited from a common ancestor and could reflect disease loci if observed more frequently in cases than controls. We found no excess of homozygous tracts in Alzheimer's disease cases compared to controls and no individual run of homozygosity showed association to Alzheimer's disease.

Examination of the Silver Colloid Binding Behavior of Disulfide-Tethered Bipyridine Ligands and Their fac-Tricarbonylrhenium(I) Complexes

The syntheses of 2,2'-bipyridin-5-ylmethyl-5-(1,2-dithiolan-3-yl)pentanoate (L1) and N-(2,2'-bipyridin-5-ylmethyl)-5-(1,2-dithiolan-3-yl)pentanamide (L2) and their neutral fac carbonylrhenium(I) complexes [Re(L1)(CO)(3)Br] and [Re(L2)(CO)(3)Br] are reported. The. electronic absorption and emission spectra of the complexes are similar to the spectrum of the reference compound [Re(bipy)(CO)(3)Br] and correlate well with the density functional theory calculations undertaken. The surface-enhanced Raman spectroscopy (SERS) spectra (excited at both 532 and 785 nm) of the ligands and complexes were examined and compared to the spectrum of ethyl 5-(1,2-dithiolan-3-yl)pentanoate (L3), revealing that there is very little contribution to the spectra of these species from the dithiolated alkyl chains. The spectra are dominated by the characteristic peaks of a metalated 2,2'-bipyridyl group,arising from the silver colloid/ion complexation, and the rhenium center. The rhenium complexes show weak SERS bands related to the CO stretches and a broad band at 510 cm(-1) assigned to Re-CO stretching. Concentration dependent studies, measured by the relative intensity of several assigned peaks, indicate that, as the surface coverage increases, the bipyridine moiety lifts off the surface In the case of L1 and L2, this gives rise to complexes with silver at low concentration, enhancing the signals observed, while for the tricarbonylbromorhenium complexes of these ligands, the presence of the disulfide tether allows an enhancement in the limits of detection of these surface-borne species of 20 times in the case of [ReL2(CO)(3)Br] over [Re(bipy)(CO)(3)Br].

Intervention With an Erythropoietin-Derived Peptide Protects Against Neuroglial and Vascular Degeneration During Diabetic Retinopathy.

OBJECTIVE:
Erythropoietin (EPO) may be protective for early stage diabetic retinopathy, although there are concerns that it could exacerbate retinal angiogenesis and thrombosis. A peptide based on the EPO helix-B domain (helix B-surface peptide [pHBSP]) is nonerythrogenic but retains tissue-protective properties, and this study evaluates its therapeutic potential in diabetic retinopathy.
RESEARCH DESIGN AND METHODS:
After 6 months of streptozotocin-induced diabetes, rats (n = 12) and age-matched nondiabetic controls (n = 12) were evenly split into pHBSP and scrambled peptide groups and injected daily (10 µg/kg per day) for 1 month. The retina was investigated for glial dysfunction, microglial activation, and neuronal DNA damage. The vasculature was dual stained with isolectin and collagen IV. Retinal cytokine expression was quantified using real-time RT-PCR. In parallel, oxygen-induced retinopathy (OIR) was used to evaluate the effects of pHBSP on retinal ischemia and neovascularization (1-30 µg/kg pHBSP or control peptide).
RESULTS:
pHBSP or scrambled peptide treatment did not alter hematocrit. In the diabetic retina, Müller glial expression of glial fibrillary acidic protein was increased when compared with nondiabetic controls, but pHBSP significantly reduced this stress-related response (P < 0.001). CD11b+ microglia and proinflammatory cytokines were elevated in diabetic retina responses, and some of these responses were attenuated by pHBSP (P < 0.01-0.001). pHBSP significantly reduced diabetes-linked DNA damage as determined by 8-hydroxydeoxyguanosine and transferase-mediated dUTP nick-end labeling positivity and also prevented acellular capillary formation (P < 0.05). In OIR, pHBSP had no effect on preretinal neovascularization at any dose.
CONCLUSIONS:
Treatment with an EPO-derived peptide after diabetes is fully established can significantly protect against neuroglial and vascular degenerative pathology without altering hematocrit or exacerbating neovascularization. These findings have therapeutic implications for disorders such as diabetic retinopathy.

Spontaneous intramedullary apoptosis is present in disorders other than myelodysplasia

Myelodysplastic syndrome (MDS) is a group of hematopoietic disorders characterized by peripheral cytopenias in the presence of normo- or hypercellular dysplastic marrow. It has been suggested that premature intramedullary apoptosis may contribute to this phenomenon. We used terminal dUTP nick-end labeling (TUNEL) of bone marrow biopsy specimens and cytocentrifuge preparations from patients with MDS and a variety of other hematopoietic disorders to determine whether there is increased intramedullary apoptosis in MDS and whether any such effect is specific to MDS. TUNEL labeling of bone marrow from 24 patients with MDS revealed significant positivity in 10 of 11 patients with refractory anemia (RA), five of seven with RA and excess of blasts (RAEB), all three patients with RAEB in transformation (RAEB-t), and all three patients with RA with ring sideroblasts (RARS). The percent of positive cells ranged from 5 to 50% but showed no apparent correlation with morphological subtype. In a series of 29 patients with acute leukemia, 17 showed significant positivity (13 of 13 with myeloid disease: three M1, seven M2, one M3, two M4; four of 16 patients with lymphoid disease: one Burkitt-type lymphoma, two null acute leukemia, and one common acute lymphoid leukemia). Intramedullary apoptosis was associated with myeloid or early committed progenitor cells and was highest in secondary acute myeloid leukemia (AML). Normal bone marrow samples from 12 individuals showed no evidence of apoptosis. Our results suggest that an increased level of intramedullary apoptosis is apparent in both patients with MDS and those with AML; those with secondary AML have the highest levels. The relative absence of such findings in lymphoid malignancy suggests that the apoptotic pathways are different in this lineage.

Discovery of Main-Belt Comet P/2006 VW139 by Pan-STARRS 1

The main-belt asteroid (300163) 2006 VW139 (later designated P/2006 VW139) was discovered to exhibit comet-like activity by the Pan-STARRS1 (PS1) survey telescope using automated point-spread-function analyses performed by PS1's Moving Object Processing System. Deep follow-up observations show both a short (~10'') antisolar dust tail and a longer (~60'') dust trail aligned with the object's orbit plane, similar to the morphology observed for another main-belt comet (MBC), P/2010 R2 (La Sagra), and other well-established comets, implying the action of a long-lived, sublimation-driven emission event. Photometry showing the brightness of the near-nucleus coma remaining constant over ~30 days provides further evidence for this object's cometary nature, suggesting it is in fact an MBC, and not a disrupted asteroid. A spectroscopic search for CN emission was unsuccessful, though we find an upper limit CN production rate of Q CN 100 Myr, while a search for a potential asteroid family around the object reveals a cluster of 24 asteroids within a cutoff distance of 68 m s-1. At 70 m s-1, this cluster merges with the Themis family, suggesting that it could be similar to the Beagle family to which another MBC, 133P/Elst-Pizarro, belongs.

Airway epithelial cell apoptosis and inflammation in COPD, smokers and non-smokers

We hypothesised that primary bronchial epithelial cells (PBECs) from subjects with COPD respond differently to Pseudomonas aeruginosa lipopolysaccharide (PA LPS) after cigarette smoke extract (CSE) exposure than PBECs obtained from smokers without airflow obstruction (SWAO) and non-smokers (NS).PBECs from 16 COPD subjects, 10 SWAOand 9 NS were cultured at air-liquid interface. Cultures were incubated with CSE prior to stimulation with PA LPS. IL-6 and IL-8 were measured by ELISA and Toll-like receptor 4 expression by FACS. Activation of NF-?B was determined by western blotting and ELISA, and MAPK and caspase-3 activity by western blotting. Apoptosis was evaluated using Annexin-V staining and the terminal transferase-mediated dUTP nick end-labeling (TUNEL) methods.Constitutive release of IL-8 and IL-6 was greatest from the COPD cultures.However, CSE pre-treatment followed by PA LPS stimulation reduced IL-8 release from COPD PBECs, but increased it from cells of SWAOand NS. TLR-4 expression,MAPK and NF-?B activation in COPD cultures were reduced after CSE treatment, but not in the SWAOor NS groups, which was associated with increased apoptosis.CSE attenuates inflammatory responses to LPS in cells from people with COPD but not those from non-smoking individuals and those who smoke without airflow obstruction.

Functional analysis of the Campylobacter jejuni N-linked protein glycosylation pathway

We describe in this report the characterization of the recently discovered N-linked glycosylation locus of the human bacterial pathogen Campylobacter jejuni, the first such system found in a species from the domain Bacteria. We exploited the ability of this locus to function in Escherichia coli to demonstrate through mutational and structural analyses that variant glycan structures can be transferred onto protein indicating the relaxed specificity of the putative oligosaccharyltransferase PglB. Structural data derived from these variant glycans allowed us to infer the role of five individual glycosyltransferases in the biosynthesis of the N-linked heptasaccharide. Furthermore, we show that C. jejuni- and E. coli-derived pathways can interact in the biosynthesis of N-linked glycoproteins. In particular, the E. coli encoded WecA protein, a UDP-GlcNAc: undecaprenylphosphate GlcNAc-1-phosphate transferase involved in glycolipid biosynthesis, provides for an alternative N-linked heptasaccharide biosynthetic pathway bypassing the requirement for the C. jejuni-derived glycosyltransferase PglC. This is the first experimental evidence that biosynthesis of the N-linked glycan occurs on a lipid-linked precursor prior to transfer onto protein. These findings provide a framework for understanding the process of N-linked protein glycosylation in Bacteria and for devising strategies to exploit this system for glycoengineering.

The Role of Variation at AβPP, PSEN1, PSEN2, and MAPT in Late Onset Alzheimer's Disease

Rare mutations in AßPP, PSEN1, and PSEN2 cause uncommon early onset forms of Alzheimer's disease (AD), and common variants in MAPT are associated with risk of other neurodegenerative disorders. We sought to establish whether common genetic variation in these genes confer risk to the common form of AD which occurs later in life (>65 years). We therefore tested single-nucleotide polymorphisms at these loci for association with late-onset AD (LOAD) in a large case-control sample consisting of 3,940 cases and 13,373 controls. Single-marker analysis did not identify any variants that reached genome-wide significance, a result which is supported by other recent genome-wide association studies. However, we did observe a significant association at the MAPT locus using a gene-wide approach (p = 0.009). We also observed suggestive association between AD and the marker rs9468, which defines the H1 haplotype, an extended haplotype that spans the MAPT gene and has previously been implicated in other neurodegenerative disorders including Parkinson's disease, progressive supranuclear palsy, and corticobasal degeneration. In summary common variants at AßPP, PSEN1, and PSEN2 and MAPT are unlikely to make strong contributions to susceptibility for LOAD. However, the gene-wide effect observed at MAPT indicates a possible contribution to disease risk which requires further study.

Genome-wide association study identifies a common variant in RAD51B associated with male breast cancer risk

We conducted a genome-wide association study of male breast cancer comprising 823 cases and 2,795 controls of European ancestry, with validation in independent sample sets totaling 438 cases and 474 controls. A SNP in RAD51B at 14q24.1 was significantly associated with male breast cancer risk (P = 3.02 × 10(-13); odds ratio (OR) = 1.57). We also refine association at 16q12.1 to a SNP within TOX3 (P = 3.87 × 10(-15); OR = 1.50).

Flux and turnover of fixed carbon in soil microbial biomass of limed and unlimed plots of an upland grassland ecosystem

The influence of liming on rhizosphere microbial biomass C and incorporation of root exudates was studied in the field by in situ pulse labelling of temperate grassland vegetation with (13)CO(2) for a 3-day period. In plots that had been limed (CaCO(3) amended) annually for 3 years, incorporation into shoots and roots was, respectively, greater and lower than in unlimed plots. Analysis of chloroform-labile C demonstrated lower levels of (13)C incorporation into microbial biomass in limed soils compared to unlimed soils. The turnover of the recently assimilated (13)C compounds was faster in microbial biomass from limed than that from unlimed soils, suggesting that liming increases incorporation by microbial communities of root exudates. An exponential decay model of (13)C in total microbial biomass in limed soils indicated that the half-life of the tracer within this carbon pool was 4.7 days. Results are presented and discussed in relation to the absolute values of (13)C fixed and allocated within the plant-soil system.

Fasciola hepatica:Histological demonstration of apoptosis in the reproductive organs of flukes of triclabendazole-sensitive and triclabendazole-resistant isolates, and in field-derived flukes from triclabendazole-treated hosts, using in situ hybridisation to visualise endonuclease-generated DNA strand breaks

Investigation of the triclabendazole (TCBZ) resistance status of populations of Fasciola hepatica in field cases of fasciolosis, where treatment failure has been reported, can be supported by histological examination of flukes collected from recently treated hosts. In TCBZ-sensitive flukes (TCBZ-S) exposed to TCBZ metabolites for 1-4. days in vivo, but not in TCBZ-resistant flukes (TCBZ-R), morphological changes suggestive of apoptosis occur in cells undergoing meiosis or mitosis in the testis, ovary and vitelline follicles. In order to verify or refute the contention that efficacy of TCBZ treatment is associated with apoptosis in the reproductive organs of flukes, histological sections of TCBZ-S (Cullompton isolate) flukes and TCBZ-R (Sligo isolate) flukes were subjected to the TdT-mediated dUDP nick end labelling (TUNEL) in situ hybridisation method, a commercially available test specifically designed to label endonuclease-induced DNA strand breaks associated with apoptosis. Additionally, sections of in vivo-treated and untreated flukes originating from field outbreaks of suspected TCBZ-S and TCBZ-R fasciolosis were labelled by the TUNEL method. It was found that in treated TCBZ-S flukes, strong positive labelling indicating apoptosis was associated with morphologically abnormal cells undergoing mitosis or meiosis in the testis, ovary and vitelline follicles. Background labelling in the positive testis sections was attributed to heterophagy of cell debris by the sustentacular tissue. The triggering of apoptosis was probably related to failure of spindle formation at cell division, supporting the contention that TCBZ inhibits microtubule formation. In treated TCBZ-R (Sligo Type 1) flukes, and in treated flukes from field outbreaks of suspected TCBZ-R fasciolosis, no significant labelling was observed, while sections of fluke derived from a field case of fasciolosis where TCBZ resistance was not suspected were heavily labelled. Light labelling was associated with the testis of untreated Cullompton (TCBZ-S) and Sligo Type 2 (TCBZ-R) flukes, which exhibit abnormal spermatogenesis and spermiogenesis, respectively. This was attributed to apoptosis and to heterophagy of effete germ line cells by the sustentacular tissue. It is concluded that demonstration of apoptosis by in situ hybridisation using the TUNEL method on sections of 1-4. days in vivo TCBZ-treated F. hepatica can contribute to the diagnosis of TCBZ resistance in field outbreaks of fasciolosis. © 2012 Elsevier B.V.