Abnormal Epidermal Keratinization in the repeated epilation mutant mouse

Repeated epilation (Er) is a radiation-induced, autosomal, incomplete dominant mutation in mice which is expressed in heterozygotes but is lethal in the homozygous condition. Many effects of the mutation occur in skin: the epidermis in Er/Er mice is adhesive (oral and nasal orifices fuse, limbs adhere to the body wall), hyperplastic, and fails to undergo terminal differentiation. Skin from fetal +/+, Er/+ and Er/Er mice at ages pre- and postkeratinization examined by light, scanning, and transmission electron microscopy showed marked abnormalities in tissue architecture, differentiation, and cell structure; light and dark basal epidermal cells were separated by wide intercellular spaces, joined by few desmosomes, and contained phagolysomes. The numbers of spinous, granular, and superficial layers were highly variable within any given region and among various regions of the body. In some areas, 2-8 layers of granular cells, containing large or diminutive keratohyalin granules, extended to the epidermal surface; in others, the granular layers were covered by several layers of partially keratinized or nonkeratinized cells. In rare instances, a single or small group of cornified cells was present among the granular layers but was not associated with the epidermal surface. Both the granular and nonkeratinized/partially keratinized upper epidermal layers Er/Er skin gave positive immunofluorescence with antiserum to the histidine-rich, basic protein, filaggrin. Proteins in epidermal extracts from +/+, Er/+ and Er/Er mice were separated and identified by radio- and immunolabeling techniques. The Er/Er extract was missing a 26.5- kdalton protein and had an altered ratio of bands in the keratin region. The 26.5-kdalton band was histidine-rich and cross-reacted with the antiserum to rat filaggrin. Several high molecular weight bands present in both Er/Er and +/+ extracts also reacted with the antiserum. These are presumed to be the precursors of filaggrin and to account for the immunofluorescence om Er/Er epidermis even though the product protein is absent. The morphologic and biochemical data indicated that the genetic defect has a general and profound influence on epidermal differentiation, including alteration of two proteins (filaggrin and keratin) important in normal terminal differentiation, tissue architecture, and cytology. Identification of epidermal abnormalities at early stages of development (prekeratinization) and defective structure of other tissues and gross anatomy suggest that the mutation is responsible for a defect in same regulatory step important in many processes of differentiation and development.     

The lipids and phospholipids of hydatid protoscolices of Echinococcus granulosus (cestoda)

Frayha G. J., Bahr G. M. and Haddad R. 1980. The lipids and phospholipids of hydatid protoscolices of Echinococcus granulosus (Cestoda). International Journal for Parasitology10: 213–216. The protoscolices of Echinococcus granulosus were isolated from hydatid cysts. The phospho- and neutral lipids of the protoscolices were determined. The seven major classes of lipids namely, phospholipids, fatty acids, mono-, di- and triglycerides, cholesterol and cholesterol esters were identified and quantitatively determined. The phospholipids isolated were cephalin, lecithin, lysolecithin, phosphatidyl inositol, phosphatidyl serine and sphingomyelin. Lecithin and cephalin were the most abundant. The signiflcance of this finding is discussed.     

Isolation and characterization of the major form of polyprenyl-phospho- mannose from Mycobacterium smegmatis

We isolated from the endogenous polyprenyl-phospho-sugar pool of Mycobacterium smegmatis two mannose-containing compounds, i.e., a partially saturated C35-octahydroheptaprenyl-P-mannose and a fully unsaturated C50-decaprenyl-P-mannose. The relative amount of C35- polyprenyl-P-mannose in mycobacterial cells was comparable to that of decaprenyl- P-pentoses and, at least, an order of magnitude higher than that of C50-decaprenyl-P-mannose. The major form of mycobacterial polyprenyl-P-mannose was structurally characterized by combined gas chromatography-mass spectrometry, fast-atom bombardment tandem mass spectrometry and proton-nuclear magnetic resonance spectroscopy as beta- d-mannopyranosyl-monophospho-(C35)octahydroheptapren ol of which all three isoprene units have Z ( cis ) configuration. The differences in the structure and cellular concentrations of the mycobacterial mannosyl- P-polyprenols reflect distinct biochemical pathways of the two compounds and suggest the existence of specific GDP-Man:polyprenyl-P mannosyltransferases (synthetases) able to distinguish between C35- octahydroheptaprenyl- and C50-decaprenyl- phosphates of mycobacteria. Since the 6'-O-mycoloylated form of C35-octahydroheptaprenyl-P-mannose isolated from M. smegmatis is apparently involved in mycolate rather than mannosyl transfer reactions, we speculate that a catabolic pathway responsible for degradation of C35-P-mannose and recycling C35- octahydroheptaprenyl phosphate might exist in mycobacteria.      

Core structures of polysialylated glycans present in neural cell adhesion molecule from newborn mouse brain.

Polysialylation of the neural cell adhesion molecule (N-CAM) is known to destabilize cell-cell adhesion and to promote plasticity in cell-cell interactions. To gain more insights into the molecular mechanisms regulating the selective expression of polysialic acid on distinct glycan chains, the underlying core structures of polysialylated N-CAM glycans from newborn mouse brain were examined. Starting from low picomolar amounts of oligosaccharides, a multistep approach was used that was based on various mass spectrometric techniques with minimized sample consumption. Evidence could be provided that polysialylated murine N-CAM glycans comprise diantennary, triantennary and tetraantennary core structures carrying, in part, type-1 N-acetyllactosamine antennae, sulfate groups linked to terminal galactose or subterminal N-acetylglucosamine residues and, as a characteristic feature, a sulfated glucuronic acid unit which was bound exclusively to C3 of terminal galactose in Manalpha3-linked type-2 antennae. Hence, our results reveal that part of the murine N-CAM carbohydrates are modified within a single oligosaccharide by polysialic acid plus a HSO3-GlcA-moiety, which is likely to represent a HNK1-epitope. As HNK1-carbohydrates are also known to modulate cell-cell interactions, the simultaneous presence of both carbohydrate epitopes may reflect a new mechanism involved in the fine-tuning of N-CAM functions.     

Classical Noncholinergic Neurotransmitters and the Vesicular Transport System for Acetylcholine

Abstract: The acetylcholine transporter exhibits such low affinity and specificity for acetylchoiine that it appeared possible it could fail to select against other neurotransmitters. Potential interactions of classical noncholinergic neurotransmitters with cholinergic synaptic vesicles purified from electric organ were studied. No active transport of [³H]serotonin, [³H]noradrenaline, or [³H]glutamate occurred. Serotonin, noradrenaline, and N -acetylaspartyl glutamate inhibited active transport of [³H]acetylcholine by the vesicles. Dopamine previously had been shown to inhibit transport. Glutamate and γ-aminobutyric acid were shown here not to inhibit active transport of [³H]-acetylcholine. Noradrenaline was competitive with respect to [³H]acetylcholine in this effect. Serotonin, noradrenaline, and dopamine inhibited binding of [³H]vesamicol to the vesicles, and dopamine was a competitive inhibitor of the binding of this allosteric ligand of the acetylcholine transporter. The results indicate that the acetylcholine transporter does not transport any other classical neurotransmitter, but serotonin, noradrenaline, and dopamine bind to the acetylcholine site.     

犬MC1R基因R306ter与毛色性状相关性研究

目的　分析犬MC1R基因中R30 6ter位点多态性与犬毛色表型的相关性 ,为遗传育种 ,培育出更加优良的实验用犬奠定基础。方法　采用PCR SSCP技术 ,对MC1R基因R30 6ter位点进行基因多态性检测 ,分析位点多态性与毛色性状之间的相关性 ,并对该位点进行克隆测序。结果　PCR SSCP分析结果表明 ,R30 6ter位点序列具有多态性 ,表现为C、D二个等位基因和CC、CD及DD三种基因型。对R30 6ter多态性片段克隆测序发现 ,MC1R基因在编码第 30 6位氨基酸的密码子处存在一个由CGA到TGA的终止突变。结论　经统计分析结果表明在杂种犬中MC1R基因多态性与毛色性状不存在显著的相关性 ,这可能是由于外科手术学教学用犬是杂种犬 ,其遗传背景不同所致。由于MC1R基因的R30 6ter位点内存在碱基变异 ,因此在杂种犬中表现出明显的PCR SSCP多态性     

吸氧预处理对大鼠脑缺血再灌注损伤的保护作用

目的探讨吸氧预处理对大鼠脑缺血再灌注损伤的保护作用。方法通过大鼠局灶脑缺血再灌注损伤模型,采用SOD、MDA测定、电镜及神经行为学检查的方法,观察吸氧预处理对大鼠脑缺血再灌注损伤后SOD、MDA、神经行为学评分及脑组织病理变化。结果吸氧预处理组SOD活力高于对照组(P<0.05),MDA含量、神经行为学评分均低于对照组(P<0.05),脑组织超微结构损伤均减轻。结论吸氧预处理对大鼠脑缺血再灌注损伤有保护作用。     

Framework for modelling data uncertainty in life cycle inventories

Modelling data uncertainty is not common practice in life cycle inventories (LCI), although different techniques are available for estimating and expressing uncertainties, and for propagating the uncertainties to the final model results. To clarify and stimulate the use of data uncertainty assessments in common LCI practice, the SETAC working group ‘Data Availability and Quality’ presents a framework for data uncertainty assessment in LCI. Data uncertainty is divided in two categories: (1) lack of data, further specified as complete lack of data (data gaps) and a lack of representative data, and (2) data inaccuracy. Filling data gaps can be done by input-output modelling, using information for similar products or the main ingredients of a product, and applying the law of mass conservation. Lack of temporal, geographical and further technological correlation between the data used and needed may be accounted for by applying uncertainty factors to the non-representative data. Stochastic modelling, which can be performed by Monte Carlo simulation, is a promising technique to deal with data inaccuracy in LCIs.     

Calpain activation is involved in early caspase-independent neurodegeneration in the hippocampus following status epilepticus

Evidence for increased calpain activity has been described in the hippocampus of rodent models of temporal lobe epilepsy. However, it is not known whether calpains are involved in the cell death that accompanies seizures. In this work, we characterized calpain activation by examining the proteolysis of calpain substrates and in parallel we followed cell death in the hippocampus of epileptic rats. Male Wistar rats were injected with kainic acid (10 mg/kg) intraperitoneally and killed 24 h later, after development of grade 5 seizures. We observed a strong Fluoro-Jade labeling in the CA1 and CA3 areas of the hippocampus in the rats that received kainic acid, when compared with saline-treated rats. Immunohistochemistry and western blot analysis for the calpain-derived breakdown products of spectrin showed evidence of increased calpain activity in the same regions of the hippocampus where cell death is observed. No evidence was found for caspase activation, in the same conditions. Treatment with the calpain inhibitor MDL 28170 significantly prevented the neurodegeneration observed in CA1. Taken together, our data suggest that early calpain activation, but not caspase activation, is involved in neurotoxicity in the hippocampus after status epilepticus .     

Estrogen regulation of ion transporter messenger RNA levels in mouse efferent ductules are mediated differentially through estrogen receptor (ER) alpha and ER beta.

Earlier studies have shown that the efferent ductules (ED) of the male mouse are a target for estrogen. The loss of estrogen receptor (ER) function through either knockout technology (alpha ERKO mouse) or chemical interference (pure antagonist, ICI 182 780) results in a failure of a major function of the ED, the reabsorption of testicular fluids. The purpose of this study was to test the hypothesis that estrogen controls fluid (water) reabsorption in the ED by modulating ion transporters important for passive water movement through a leaky epithelium such as the ED. Northern blot analysis was used to detect the mRNA levels for key ion transporters in the following experimental groups: 1) wild-type (WT) control for the 14-day experiment, 2) ER alpha knockout (alpha ERKO) control for the 14-day experiment, 3) WT treated with ICI 182 780 (ICI) for 14 days, 4) alpha ERKO treated with ICI for 14 days, 5) WT control for the 35-day experiment, and 6) WT treated with ICI for 35 days. Estrogen differentially modulated the mRNA levels of key ion transporters. ER alpha mediated carbonic anhydrase II mRNA abundance, and there was a decrease in Na(+)/H(+) exchanger 3 mRNA levels in the alpha ERKO that appeared to be a cellular effect and not a direct estrogen effect. The loss of ER alpha control resulted in an increase in mRNA abundance for the catalytic subunit of Na(+)-K(+) ATPase alpha 1, whereas an increase in the mRNA abundance of the Cl(-)/HCO(3)(-) exchanger and the chloride channel cystic fibrosis transmembrane regulator was significantly ER beta mediated. Our results indicate for the first time that estrogen acting directly and indirectly through both ER alpha and ER beta probably modulates fluid reabsorption in the adult mouse ED by regulating the expression of ion transporters involved in the movement of Na(+) and Cl(-).