Functional and antigenic properties of GlpO from Mycoplasma mycoides subsp. mycoides SC: characterization of a flavin adenine dinucleotide-binding site deletion mutant

L-alpha-glycerophosphate oxidase (GlpO) plays a central role in virulence of Mycoplasma mycoides subsp. mycoides SC, a severe bacterial pathogen causing contagious bovine pleuropneumonia (CBPP). It is involved in production and translocation of toxic H(2)O(2) into the host cell, causing inflammation and cell death. The binding site on GlpO for the cofactor flavin adenine dinucleotide (FAD) has been identified as Gly(12)-Gly(13)-Gly(14)-Ile(15)-Ile(16)-Gly(17). Recombinant GlpO lacking these six amino acids (GlpODeltaFAD) was unable to bind FAD and was also devoid of glycerophosphate oxidase activity, in contrast to non-modified recombinant GlpO that binds FAD and is enzymatically active. Polyclonal monospecific antibodies directed against GlpODeltaFAD, similarly to anti-GlpO antibodies, neutralised H(2)O(2) production of M. mycoides subsp. mycoides SC grown in the presence of glycerol, as well as cytotoxicity towards embryonic calf nasal epithelial (ECaNEp) cells. The FAD-binding site of GlpO is therefore suggested as a valuable target site for the future construction of deletion mutants to yield attenuated live vaccines of M. mycoides subsp. mycoides SC necessary to efficiently combat CBPP.

Do N-arachidonyl-glycine (NA-glycine) and 2-arachidonoyl glycerol (2-AG) share mode of action and the binding site on the β 2 subunit of GABA A receptors?

NA-glycine is an endogenous lipid molecule with analgesic properties, which is structurally similar to the endocannabinoids 2-AG and anandamide but does not interact with cannabinoid receptors. NA-glycine has been suggested to act at the G-protein coupled receptors GPR18 and GPR92. Recently, we have described that NA-glycine can also modulate recombinant α1β2γ2 GABAA receptors. Here we characterize in more detail this modulation and investigate the relationship of its binding site with that of the endocannabinoid 2-AG.

Molecular analysis of the site for 2-arachidonylglycerol (2-AG) on the β 2 subunit of GABA A receptors

2-arachidonyl glycerol (2-AG) allosterically potentiates GABAA receptors via a binding site located in transmembrane segment M4 of the β2 subunit. Two amino acid residues have been described that are essential for this effect. With the aim to further describe this potential drug target, we performed a cysteine scanning of the entire M4 and part of M3. All four residues in M4 affecting the potentiation here and the two already identified residues locate to the same side of the α-helix. This side is exposed to M3, where further residues were identified. From the fact that the important residues span > 18 Å, we conclude that the hydrophobic tail of the bound 2-AG molecule must be near linear and that the site mainly locates to the inner leaflet but stretches far into the membrane. The influence of the structure of the head group of the ligand molecule on the activity of the molecule was also investigated. We present a model of 2-AG docked to the GABAA receptor.

Incident malignancies among older long-term breast cancer survivors and an age-matched and site-matched nonbreast cancer comparison group over 10 years of follow-up

BACKGROUND Of the approximately 2.4 million American women with a history of breast cancer, 43% are aged ≥ 65 years and are at risk for developing subsequent malignancies. METHODS Women from 6 geographically diverse sites included 5-year breast cancer survivors (N = 1361) who were diagnosed between 1990 and 1994 at age ≥ 65 years with stage I or II disease and a comparison group of women without breast cancer (N = 1361). Women in the comparison group were age-matched and site-matched to breast cancer survivors on the date of breast cancer diagnosis. Follow-up began 5 years after the index date (survivor diagnosis date or comparison enrollment date) until death, disenrollment, or through 15 years after the index date. Data were collected from medical records and electronic sources (cancer registry, administrative, clinical, National Death Index). Analyses included descriptive statistics, crude incidence rates, and Cox proportional hazards regression models for estimating the risk of incident malignancy and were adjusted for death as a competing risk. RESULTS Survivors and women in the comparison group were similar: >82% were white, 55% had a Charlson Comorbidity Index of 0, and ≥ 73% had a body mass index ≤ 30 kg/m(2) . Of all 306 women (N = 160 in the survivor group, N = 146 in the comparison group) who developed a first incident malignancy during follow-up, the mean time to malignancy was similar (4.37 ± 2.81 years vs 4.03 ± 2.76 years, respectively; P = .28), whereas unadjusted incidence rates were slightly higher in survivors (1882 vs 1620 per 100,000 person years). The adjusted hazard of developing a first incident malignancy was slightly elevated in survivors in relation to women in the comparison group, but it was not statistically significant (hazard ratio, 1.17; 95% confidence interval, 0.94-1.47). CONCLUSIONS Older women who survived 5 years after an early stage breast cancer diagnosis were not at an elevated risk for developing subsequent incident malignancies up to 15 years after their breast cancer diagnosis.

Local recurrence after retropubic radical prostatectomy for prostate cancer does not exclusively occur at the anastomotic site

What's known on the subject? and What does the study add? Local recurrence after radical prostatectomy (RP) for clinically organ-confined prostate cancer is largely assumed to occur at the anastomotic site, as reflected in European and North American guidelines for adjuvant and salvage radiotherapy after RP. However, the exact site of local recurrence often remains undetermined. The present study shows that roughly one out of five patients with local recurrence after RP has histologically confirmed tumour deposits at the resection site of the vas deferens, clearly above the anastomotic site. This should be considered when offering ‘blind’ radiotherapy to the anastomotic site in patients with biochemical recurrence alone. Objective To determine the anatomical pattern of local recurrence and the corresponding clinical and pathological variables of patients treated with retropubic radical prostatectomy (RRP). Patients and Methods In all, 41 patients with biopsy confirmed local recurrence after extended pelvic lymph node dissection and RRP performed between January 1992 and December 2009 at a single tertiary referral academic centre were retrospectively studied. The site of local recurrence as assessed on computed tomography or magnetic resonance imaging was reviewed. Two sites were identified: the vesicourethral anastomotic site and the cranial resection margin of the surgical bed, where the vas deferens was transected and clipped. Age and serum prostate-specific antigen (PSA) level at RRP, pathological tumour and nodal stage, Gleason score, tumour location, surgical margin status, age and serum PSA level at the time of local recurrence, and time to diagnosis of local recurrence were assessed for the two sites and compared with the chi-square or Wilcoxon rank sum tests as appropriate. Results Local recurrence occurred at the anastomotic site in 31/41 (76%) patients and at the resection site of the vas deferens in nine of 41 (22%) patients. One patient had distinct lesions at both sites. There was no significant difference in any of the clinical and pathological variables between patients with local recurrence in the former and latter site. Conclusion Most local recurrences after RRP occur exclusively at the anastomotic site. However, 22% of locally recurrent cases had tumour at the resection site of the vas deferens. This should be taken into account when considering adjuvant or salvage radiation therapy.

Computational and experimental methodology for site-matched investigations of the influence of mineral mass fraction and collagen orientation on the axial indentation modulus of lamellar bone

Relationships between mineralization, collagen orientation and indentation modulus were investigated in bone structural units from the mid-shaft of human femora using a site-matched design. Mineral mass fraction, collagen fibril angle and indentation moduli were measured in registered anatomical sites using backscattered electron imaging, polarized light microscopy and nano-indentation, respectively. Theoretical indentation moduli were calculated with a homogenization model from the quantified mineral densities and mean collagen fibril orientations. The average indentation moduli predicted based on local mineralization and collagen fibers arrangement were not significantly different from the average measured experimentally with nanoindentation (p=0.9). Surprisingly, no substantial correlation of the measured indentation moduli with tissue mineralization and/or collagen fiber arrangement was found. Nano-porosity, micro-damage, collagen cross-links, non-collagenous proteins or other parameters affect the indentation measurements. Additional testing/simulation methods need to be considered to properly understand the variability of indentation moduli, beyond the mineralization and collagen arrangement in bone structural units.

Dimerization of β-site β-amyloid precursor protein-cleaving enzyme

Cleavage of the beta-amyloid precursor protein (APP) by the aspartyl protease beta-site APP-cleaving enzyme (BACE) is the first step in the generation of the amyloid beta-peptide, which is deposited in the brain of Alzheimer's disease patients. Whereas the subsequent cleavage by gamma-secretase was shown to originate from the cooperation of a multicomponent complex, it is currently unknown whether in a cellular environment BACE is enzymatically active as a monomer or in concert with other proteins. Using blue native gel electrophoresis we found that endogenous and overexpressed BACE has a molecular mass of 140 kDa instead of the expected mass of 70 kDa under denaturing conditions. This suggests that under native conditions BACE exists as a homodimer. Homodimerization was confirmed by co-immunoprecipitation of full-length BACE carrying different epitope tags. In contrast, the soluble active BACE ectodomain was exclusively present as a monomer both under native and denaturing conditions. A domain analysis revealed that the BACE ectodomain dimerized as long as it was attached to the membrane, whereas the cytoplasmic domain and the transmembrane domain were dispensable for dimerization. By adding a KKXX-endoplasmic reticulum retention signal to BACE, we demonstrate that dimerization of BACE occurs already before full maturation and pro-peptide cleavage. Furthermore, kinetic analysis of the purified native BACE dimer revealed a higher affinity and turnover rate in comparison to the monomeric soluble BACE. Dimerization of BACE might, thus, facilitate binding and cleavage of physiological substrates.

An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120--800 ka

An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice), combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present) (Lemieux-Dudon et al., 2010). In this paper, together with the companion paper of Veres et al. (2013), we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012) chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120–800 ka. In this framework, new measurements of δ18Oatm over Marine Isotope Stage (MIS) 11–12 on EDC and a complete δ18Oatm record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18Oatm, δO2/N2 and air content) has been verified before implementation in AICC2012. The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka) is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.

Early Iron Age Kinneret – Early Aramaean or Just Late Canaanite? Remarks on the Material Culture of a Border Site in Northern Palestine at the Turn of an Era

In recent years, scholars have identified Early Iron Age Kinneret as belonging either to the kingdom of Geshur1 or at least as being part of an early Aramaean polity.2 It is the purpose of this paper to reexamine the archaeological evidence for such an assumption and to critically test the currently available data against this hypothesis.