O-raffinose crosslinked hemoglobin lacks site-specific chemistry in the central cavity: structural and functional consequences of beta93Cys modification

Reacting human deoxyHbA0 with oxidized raffinose (O-raffinose), a trisaccharide, results in a low oxygen affinity "blood substitute," stabilized in a noncooperative T-conformation and possesses readily oxidizable rhombic heme. In this study, we fractionated the O-raffinose-modified HbA0 heterogeneous polymer (O-R-PolyHbA0) into six distinct fractions with a molecular weight distribution ranging from 64 to approximately 600 kDa using size-exclusion chromatography (SEC). Oxygen equilibrium and kinetics binding parameters of all fractions were nearly identical, reflecting a lack of heterogeneity in ligand binding properties among O-R-PolyHbA0 species (Hill coefficient n equal to 1.0). Several mass spectrometry techniques were used to evaluate undigested and digested HbA0, O-R-PolyHbA0, and O-R-PolyHbA0 fractions. Proposed sites of intramolecular crosslinking (i.e., beta1Lys82, beta2Lys82, and beta1Val1) were not found to be the predominant site of crosslinking within the central cavity. Intermolecular crosslinking with O-raffinose results in no discernible site of amino acids modifications with the exception of beta93Cys and alpha104Cys. Based on accessible surface area (ASA) calculations in intact deoxyHbA0, slight conformational changes are required to allow for the S on alpha104Cys to be modified during the reaction with O-raffinose or its partially oxidized product(s). The stabilization of HbA0 in the T-conformation may not be a direct correlate of O-raffinose induced changes, but an indirect consequence of changing hydration in the water-filled central cavity and/or the distal heme pocket leading in the latter case to accelerated iron oxidation. Structural data presented here when taken together with the oxidative instability of O-R-PolyHbA0 may provide some basis for the reported toxicity of this oxygen carrier.     

Optimization of protocols for microinjection-based delivery of cryoprotective agents into Japanese whiting Sillago japonica embryos

Microinjection has proven useful for introduction of low-permeability cryoprotective agents (CPAs) into fish eggs or embryos for cryopreservation. In this work, we examined the suitable conditions for single or combined microinjection into the perivitelline space (PS) and the yolk mass (YM) of embryos of the Japanese whiting, an alternative marine fish model for embryo cryopreservation studies. The parameters examined were injection volume, CPA type and concentration, vehicle (diluent), and suitable developmental stage. Somites and tail elongation embryos tolerated single or combined injection with 2.1 and 15.6 nl in the PS and YM, respectively, whereas earlier embryonic stages tolerated only up to 8.2 nl in the YM. The injected solutions diffused rapidly throughout the PS and YM and remained contained within each compartment unless in the case of structural damage caused by injection of larger volumes. Yamamoto solution was marginally better as a vehicle for microinjection of CPAs than fish Ringer and phosphate buffer saline whereas ¼ artificial sea water was clearly unsuitable. Ethylene glycol was well tolerated by embryos in all developmental stages whereas 1, 2-propylene glycol was suitable only for early embryonic stages. Overall, microinjection was efficient in delivering high loads of CPAs inside whiting embryos more swiftly than previously obtained for this species by immersion-based impregnation protocols. Embryos microinjected with CPAs showed a decrease in embryo nucleation temperature and an increase in chilling tolerance. CPA-microinjected embryos will provide valuable materials to optimize the remaining parameters that are critical for successful cryopreservation such as cooling and warming strategies.     

Quantification of 3-ketodihydrosphingosine using HPLC-ESI-MS/MS to study SPT activity in yeast Saccharomyces cerevisiae

Serine palmitoyltransferase (SPT) catalyzes the rate-limiting step of condensation of L-serine and palmitoyl-CoA to form 3-ketodihydrosphingosine (3KDS). Here, we report a HPLC-ESI-MS/MS method to directly quantify 3KDS generated by SPT. With this technique, we were able to detect 3KDS at a level comparable to that of dihydrosphingosine in yeast Saccharomyces cerevisiae. An in vitro SPT assay measuring the incorporation of deuterated serine into deuterated 3KDS was developed. The results show that SPT kinetics in response to palmitoyl-CoA fit into an allosteric sigmoidal model, suggesting the existence of more than one palmitoyl-CoA binding site on yeast SPT and positive cooperativity between them. Myriocin inhibition of yeast SPT activity was also investigated and we report here, for the first time, an estimated myriocin K_i for yeast SPT of approximately 10 nM. Lastly, we investigated the fate of serine α-proton during SPT reaction. We provide additional evidence to support the proposed mechanism of SPT catalytic activity in regard to proton exchange between the intermediate NH₃⁺ base formed on the active Lys residue with surrounding water. These findings establish the current method as a powerful tool with significant resolution and quantitative power to study SPT activity.     

German government investigates anti-Semitism

Anti-Semitism in Germany has a long tradition. It dates back to religious anti-Semitism many centuries ago culminating in the Holocaust. More recently, anti-Semitism was rising again in Germany. At least partly, it was encouraged by recent news reports on the Israel-Palestine conflict. This occurred at the time when a new Anti-Semitic party – the Alternative for Germany – emerged at Germany's political scene. To ascertain the prevalence of anti-Semitism, Germany's federal parliament set up an independent commission in 2012. In 2017, the commission reported its findings. This review discusses the commission's results focusing on a definition of anti-Semitism; hate crimes based on anti-Semitism; the extend of anti-Semitism in Germany's political centre; anti-Semitism in the media, social movements and racist organizations; an evaluation of anti-Semitism based on surveys and interviews; anti-Semitism in Germany's political parties; and finally, anti-Semitism of refugees and migrants. The report concludes recommendations seeking to prevent anti-Semitism.     

Body mass index,height and early-onset basal cell carcinoma in a case-control study

IntroductionBasal cell carcinoma (BCC) is the most common malignancy in the US. Body mass index (BMI) and height have been associated with a variety of cancer types, yet the evidence regarding BCC is limited. Therefore, we evaluated BMI and height in relation to early-onset BCC (under age 40) and explored the potential role of ultraviolet (UV) radiation exposure and estrogen-related exposures in the BMI-BCC relationship.MethodsBCC cases (n = 377) were identified through a central dermatopathology facility in Connecticut. Control subjects (n = 389) with benign skin conditions were randomly sampled from the same database and frequency matched to cases on age (median = 36, interquartile range 33–39), gender, and biopsy site. Participants reported weight (usual adult and at age 18), adult height, sociodemographic, phenotypic, and medical characteristics, and prior UV exposures. We calculated multivariate odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression models.ResultsAdult BMI was inversely associated with early-onset BCC (obese vs. normal OR = 0.43, 95% CI = 0.26–0.71). A similar inverse association was present for BMI at age 18 (OR = 0.54, 95% CI = 0.34–0.85). Excluding UV exposures from the BMI models and including estrogen-related exposures among women only did not alter the association between BMI and BCC, indicating limited mediation or confounding. We did not observe an association between adult height and BCC (OR per cm = 1.00, 95% CI = 0.98–1.02).ConclusionsWe found a significant inverse association between BMI and early-onset BCC, but no association between height and BCC. This association was not explained by UV exposures or estrogen-related exposures in women.