Mitochondrial uncoupling protein-2 deficiency protects steatotic mouse hepatocytes from hypoxia/reoxygenation

Steatotic livers are sensitive to ischemic events and associated ATP depletion. Hepatocellular necrosis following these events may result from mitochondrial uncoupling protein-2 (UCP2) expression. To test this hypothesis, we developed a model of in vitro steatosis using primary hepatocytes from wild-type (WT) and UCP2 knockout (KO) mice and subjected them to hypoxia/reoxygenation (H/R). Using cultured hepatocytes treated with emulsified fatty acids for 24 h, generating a steatotic phenotype (i.e., microvesicular and broad-spectrum fatty acid accumulation), we found that the phenotype of the WT and UCP2 KO were the same; however, cellular viability was increased in the steatotic KO hepatocytes following 4 h of hypoxia and 24 h of reoxygenation; Hepatocellular ATP levels decreased during hypoxia and recovered after reoxygenation in the control and UCP2 KO steatotic hepatocytes but not in the WT steatotic hepatocytes; mitochondrial membrane potential in WT and UCP2 KO steatotic groups was less than control groups but higher than UCP2 KO hepatocytes. Following reoxygenation, lipid peroxidation, as measured by thiobarbituric acid reactive substances, increased in all groups but to a greater extent in the steatotic hepatocytes, regardless of UCP2 expression. These results demonstrate that UCP2 sensitizes steatotic hepatocytes to H/R through mitochondrial depolarization and ATP depletion but not lipid peroxidation.     

Four loci explain 83% of size variation in the horse

Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS) that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many genetic variants with weak effects on size, we show that horses, like other domestic mammals, carry just a small number of size loci with alleles of large effect. Furthermore, three of our horse size loci contain the LCORL, HMGA2 and ZFAT genes that have previously been found to control human height. The LCORL/NCAPG locus is also implicated in cattle growth and HMGA2 is associated with dog size. Extreme size diversification is a hallmark of domestication. Our results in the horse, complemented by the prior work in cattle and dog, serve to pinpoint those very few genes that have played major roles in the rapid evolution of size during domestication.     

Critical Role of Perforin-dependent CD8+ T Cell Immunity for Rapid Protective Vaccination in a Murine Model for Human Smallpox

Vaccination is highly effective in preventing various infectious diseases, whereas the constant threat of new emerging pathogens necessitates the development of innovative vaccination principles that also confer rapid protection in a case of emergency. Although increasing evidence points to T cell immunity playing a critical role in vaccination against viral diseases, vaccine efficacy is mostly associated with the induction of antibody responses. Here we analyze the immunological mechanism(s) of rapidly protective vaccinia virus immunization using mousepox as surrogate model for human smallpox. We found that fast protection against lethal systemic poxvirus disease solely depended on CD4 and CD8 T cell responses induced by vaccination with highly attenuated modified vaccinia virus Ankara (MVA) or conventional vaccinia virus. Of note, CD4 T cells were critically required to allow for MVA induced CD8 T cell expansion and perforin-mediated cytotoxicity was a key mechanism of MVA induced protection. In contrast, selected components of the innate immune system and B cell-mediated responses were fully dispensable for prevention of fatal disease by immunization given two days before challenge. In conclusion, our data clearly demonstrate that perforin-dependent CD8 T cell immunity plays a key role in MVA conferred short term protection against lethal mousepox. Rapid induction of T cell immunity might serve as a new paradigm for treatments that need to fit into a scenario of protective emergency vaccination.     

Online fluorescent dye detection method for the characterization of immunoglobulin G aggregation by size exclusion chromatography and asymmetrical flow field flow fractionation

The aim of this study was to develop an online fluorescent dye detection method suitable for high-pressure size exclusion chromatography (HP-SEC) and asymmetrical flow field flow fractionation (AF4). The noncovalent extrinsic fluorescent dye 4,4′-dianilino-1,1′-binaphthyl-5,5′-disulfonic acid (Bis-ANS) was added to the mobile phase or the sample, and the fluorescence emission at 488 nm was recorded on excitation at 385 nm. By combining HP-SEC and AF4 with online dye detection, it was possible to simultaneously detect heat-induced aggregation and structural changes of monomeric and aggregated immunoglobulin G (IgG); an increase in Bis-ANS fluorescence was observed in both the aggregate and monomer fractions. These structural changes of individual fractions, which were not detectable by online UV and multiangle laser light scattering (MALLS) or by stand-alone dynamic light scattering (DLS), intrinsic IgG fluorescence, and far-UV circular dichroism (CD), resulted in progressive aggregation on storage. The developed online fluorescent dye detection for HP-SEC or AF4 with Bis-ANS is a powerful method to detect both aggregation and structural changes of both monomeric and aggregated IgG in heat-stressed formulations.     

Self assembly of a Fe(L) complex with octacyano metallates [M(CN)8] (L = pentadentate macrocyclic ligand, M = Mo, W): Crystal structure and magnetic properties

The self assembly of [Fe^III(L)]Cl₂ClO₄ (L = pentadentate macrocyclic ligand) with octacyano metallates [M^IV(CN)₈]⁴⁻ (M = Mo, W) leads to bimetallic cyano-bridged 2-D coordination polymers of formula [{Fe(L)}₃{M(CN)₈}₂]Cl·xH₂O with M = Mo (2), or W (3). The structure of the tungsten analogue has been established by single crystal X-ray diffraction. The magnetic properties for both Mo and W derivative are reported.     

Libri Novi

Ohne Zusammenfassung     

Insulin secretion in the hibernating edible dormouse (Glis glis): in vivo and in vitro studies

Plasma glucose and insulin have been studied during lethargy and spontaneous arousal of hibernating edible dormouse. During lethargy blood glucose was low while plasma insulin remained at the same level as in other seasons. Plasma glucose and insulin did not fluctuate along the phase of lethargy. During spontaneous arousal plasma insulin rose strongly from the 17 degrees C stage, reaching the higher values at 26 degrees C while blood glucose was only 85 mg/100 ml, then decreased at 37 degrees C. The effect of glucose and temperature on insulin secretion was studied using perfused pancreas preparation from hibernating edible dormice. During the rewarming of the edible dormouse pancreas the insulin release did not occur in response to the absolute extracellular glucose level but occurred in response to a B cell membrane phenomenon which was dependent on the changing rate of glucose level. The effect of glucose and temperature on insulin secretion from perfused pancreas was compared between edible dormouse and homeotherm permanent, the rat. The B cell response to glucose of the dormouse pancreas increased up to 15 degrees C whereas that of the rat only from 25 degrees C. The dormouse insulin secretion reached a peak value at the 30 degrees C of temperature, whereas that of the rat progressively increased until 37 degrees C. These results showed that some biochemical adjustment or process of acclimatization took place in the B cells of the hibernators.     

Comparison of Stainless-Steel Closures and Cotton Plugs in Maintaining Contamination-free Medium in Circulating Air

Culture flasks capped with stainless-steel closures became contaminated when incubated in circulating air. Cotton plugs prevented this contamination.