Association between microscopic brain damage as indicated by magnetization transfer imaging and anticardiolipin antibodies in neuropsychiatric lupus

The pathogenetic role of anticardiolipin antibodies (aCLs) in patients with neuropsychiatric systemic lupus erythematosus (NPSLE) without cerebral infarcts remains elusive. Magnetization transfer imaging (MTI) has proved to be a sensitive tool for detecting diffuse microscopic brain damage in NPSLE patients. In this study we examined the correlation between grey and white matter magnetization transfer ratio (MTR) parameters and the presence of IgM and IgG aCLs and lupus anticoagulant in 18 patients with systemic lupus erythematosus and a history of NPSLE but without cerebral infarcts on conventional magnetic resonance imaging. Lower grey matter mean MTR (P < 0.05), white matter mean MTR (P < 0.05), white matter peak location (P < 0.05) and grey matter peak location (trend toward statistical significance) were observed in IgM aCL-positive patients than in IgM aCL-negative patients. No significant differences were found in MTR histogram parameters with respect to IgG aCL and lupus anticoagulant status, nor with respect to anti-dsDNA or anti-ENA (extractable nuclear antigen) status. This is the first report of an association between the presence of aCLs and cerebral damage in grey and white matter in NPSLE. Our findings suggest that aCLs are associated with diffuse brain involvement in NPSLE patients.     

The ATP-dependent helicase RUVBL1/TIP49a associates with tubulin during mitosis

RUVBL1/TIP49a/Pontin52 is a recently identified multi-functional protein with 2 ATP binding (WALKER) sites, which is essential for cell proliferation. We recovered and identified RUVBL1/TIP49a as a tubulin-binding protein from Triton X-100 lysates of U937 promonocytic cells by protein affinity chromatography and tryptic peptide microsequencing. Performing co-immunoprecipitation using newly generated RUVBL1/TIP49a-specific antibodies (mAb and rabbit polyclonal Ab) and RUVBL1/TIP49a-GST fusion protein-pull down assays we demonstrate co-precipitation of alpha- and gamma tubulin with RUVBL1/TIP49a. Confocal immunoflourescence microscopy reveals that RUVBL1/TIP49a was present not only in the nucleus, as expected, but was also concentrated at the centrosome and at the mitotic spindle in colocalization with tubulin. The topology of RUVBL1/TIP49a at the mitotic spindle varied, depending on the mitotic stage. The protein was localized at the centrosome and at the polar and astral microtubules in metaphase, and was detectable at the zone of polar tubule interdigitation in anaphase B and telophase. During cytokinesis the protein reappeared at the area of decondensing chromosomes. Whereas preincubation of U937 cells with colcemid resulted in inhibition of mitotic spindle formation with subsequent loss of RUVBL1/TIP49a mitotic spindle staining, no relevant influence of colcemid on RUVBL1/TIP49a-tubulin binding was observed. An agonistic effect of RUVBL1/TIP49a on in vitro tubulin assembly is demonstrated. Our results reveal a new functional aspect of RUVBL1/TIP49a.     

Flexible working hours, health, and well-being in Europe: some considerations from a SALTSA project

The project brought together researchers from 9 EU-Countries and resulted in a number of actions, in particular the following: (a) There is an urgent need of defining the concept of flexible working hours, since it has been used in many different and even counterintuitive ways; the most obvious distinction is where the influence over the working hours lies, that is between the “company-based flexibility” and the “individual-oriented flexibility”; (b) The review of the Legislation in force in the 15 European countries shows that the regulation of working times is quite extensive and covers (Council Directive 93/104/EC) almost all the various arrangements of working hours (i.e., part-time, overtime, shift, and night work), but fails to provide for flexibility; (c) According to the data of the Third EU Survey on Working Conditions, longer and “irregular” working hours are in general linked to lower levels of health and well-being; moreover, low (individual) flexibility and high variability of working hours (i.e., company-based flexibility) were consistently associated with poor health and well-being, while low variability combined with high autonomy showed positive effects; (d) Six substudies from different countries demonstrated that flexible working hours vary according to country, economic sector, social status, and gender; overtime is the most frequent form of company-based flexibility but has negative effects on stress, sleep, and social and mental health; individual flexibility alleviates the negative effects of the company-based flexibility on subjective health, safety, and social well-being; (e) The literature review was able to list more than 1,000 references, but it was striking that most of these documents were mainly argumentative with very little empirical data. Thus, one may conclude that there is a large-scale intervention ongoing in our society with almost completely unknown and uncontrolled effects. Consequently, there is a strong need for systematic research and well-controlled actions in order to examine in detail what flexible working hours are considered, what and where are their positive effects, in particular, as concerns autonomy, and what regulation seem most reasonable.     

The CeCDC-14 phosphatase is required for cytokinesis in the Caenorhabditis elegans embryo

In all eukaryotic organisms, the physical separation of two nascent cells must be coordinated with chromosome segregation and mitotic exit. In Saccharomyces cerevisiae and Schizosaccharomyces pombe this coordination depends on a number of genes that cooperate in intricate regulatory pathways termed mitotic exit network and septum initiation network, respectively. Here we have explored the function of potentially homologous genes in a metazoan organism, Caenorhabditis elegans, using RNA-mediated interference. Of all the genes tested, only depletion of CeCDC-14, the C. elegans homologue of the budding yeast dual-specificity phosphatase Cdc14p (Clp1/Flp1p in fission yeast), caused embryonic lethality. We show that CeCDC-14 is required for cytokinesis but may be dispensable for progression of the early embryonic cell cycles. In response to depletion of CeCDC-14, embryos fail to establish a central spindle, and several proteins normally found at this structure are mislocalized. CeCDC-14 itself localizes to the central spindle in anaphase and to the midbody in telophase. It colocalizes with the mitotic kinesin ZEN-4, and the two proteins depend on each other for correct localization. These findings identify the CDC14 phosphatase as an important regulator of central spindle formation and cytokinesis in a metazoan organism.     

How do water transport and water storage differ in coniferous earlywood and latewood?

The goal of this research project was to determine the water transport behaviour of earlywood versus latewood in the trunk of 21-year-old Douglas-fir [Pseudostuga menziesii (Mirb.) Franco] trees. Specific conductivity (k(s)) and the vulnerability of xylem to embolism were measured on a single growth ring and in a subset of earlywood and latewood samples within the same ring. Earlywood/latewood ratio, trunk water potential (Psi) and relative water content (RWC) were used to predict differences in conductivities and vulnerability to embolism. Earlywood has about 11 times the k(s) of latewood, and up to 90% of the total flow occurred through the earlywood. Earlywood's vulnerability to embolism followed the same trend as that of the whole wood, with 50% loss of conductivity at -2.2 MPa (P(50)). Latewood was more vulnerable to embolism than earlywood at high Psi, but as Psi decreased, the latewood showed very little further embolism, with a P(50) <-5.0 MPa. The lowest trunk Psi estimated in the field was about -1.4 MPa, indicating that latewood and earlywood in the field experienced about 42% and 16% loss of k(s), respectively. The higher vulnerability to embolism in latewood than in earlywood at field Psi was associated with higher water storage capacity (21.8% RWC MPa(-1) versus 4.1% RWC MPa(-1), latewood and earlywood, respectively). The shape of the vulnerability curve suggests that air seeding through latewood may occur directly through pores in the margo and seal off at lower pressure than earlywood pores.     

不同季节和冬眠时相中达乌尔黄鼠视前区温敏神经元特性和下丘脑内NA代谢的变化

比较了不同季节和冬眠时相中达乌尔黄鼠 (Citelleusdauricus)下丘脑内去甲肾上腺素 (noradrenaline ,NA)代谢和视前区 (POA)脑片中各类温敏神经元的比例、温度敏感性、放电活动的临界温度及下限温度 .结果表明 :与夏季动物相比 ,( 1)冬眠各时相中POA温敏神经元的比例和温敏性产生了与冬眠体温调节特性相关的适应性改变 ;( 2 )冬季和冬眠中POA神经元放电的下限温度和温敏神经元活动的临界温度均显著下移 ;( 3 )冬眠中POA神经元对NA反应的敏感性增高 ,冷敏神经元对NA的反应从夏季的抑制型转变为冬眠时的兴奋型 ;( 4)入眠和深冬眠时下丘脑内NA的含量和代谢水平下降 ,出眠时代谢水平升高 .这些变化可能解释动物入眠时主动降低体温和出眠时从深低体温中快速地升温的温度调节机理 .     

Substitution bias, rapid saturation, and the use of mtDNA for nematode systematics

Only relatively recently have researchers turned to molecular methods for nematode phylogeny reconstruction. Thus, we lack the extensive literature on evolutionary patterns and phylogenetic usefulness of different DNA regions for nematodes that exists for other taxa. Here, we examine the usefulness of mtDNA for nematode phylogeny reconstruction and provide data that can be used for a priori character weighting or for parameter specification in models of sequence evolution. We estimated the substitution pattern for the mitochondrial ND4 gene from intraspecific comparisons in four species of parasitic nematodes from the family Trichostrongylidae (38-50 sequences per species). The resulting pattern suggests a strong mutational bias toward A and T, and a lower transition/transversion ratio than is typically observed in other taxa. We also present information on the relative rates of substitution at first, second, and third codon positions and on relative rates of saturation of different types of substitutions in comparisons ranging from intraspecific to interordinal. Silent sites saturate extremely quickly, presumably owing to the substitution bias and, perhaps, to an accelerated mutation rate. Results emphasize the importance of using only the most closely related sequences in order to infer patterns of substitution accurately for nematodes or for other taxa having strongly composition-biased DNA. ND4 also shows high amino acid polymorphism at both the intra- and interspecific levels, and in higher level comparisons, there is evidence of saturation at variable amino acid sites. In general, we recommend using mtDNA coding genes only for phylogenetics of relatively closely related nematode species and, even then, using only nonsynonymous substitutions and the more conserved mitochondrial genes (e.g., cytochrome oxidases). On the other hand, the high substitution rate in genes such as ND4 should make them excellent for population genetics studies, identifying cryptic species, and resolving relationships among closely related congeners when other markers show insufficient variation.      

Identification of an alpha3-fucosyltransferase and a novel alpha2- fucosyltransferase activity in cercariae of the schistosome Trichobilharzia ocellata: biosynthesis of the Fucalpha1-->2Fucalpha1-- >3[Gal(NAc)beta1-->4]GlcNAc sequence

Fucose is a major constituent of the protein- and lipid-linked glycans of the various life-cycle stages of schistosomes. These fucosylated glycans are highly antigenic and seem to play a role in the pathology of schistosomiasis. In this article we describe the identification and characterization of two fucosyltransferases (FucTs) in cercariae of the avian schistosome Trichobilharzia ocellata, a GDP-Fuc:[Galbeta1-- >4]GlcNAcbeta-R alpha1-->3-FucT and a novel GDP-Fuc:Fucalpha-R alpha1-- >2-FucT. Triton X-100 extracts of cercariae were assayed for FucT activity using a variety of acceptor substrates. Type 1 chain (Galbeta1- ->3GlcNAc) based compounds were poor acceptors, whereas those based on a type 2 chain (Galbeta1-->4GlcNAc), whether alpha2'-fucosylated, alpha3'-sialylated, or unsubstituted, and whether present as oligosaccharide or contained in a glycopeptide or glycoprotein, all served as acceptor substrates. In this respect the schistosomal alpha3- FucT resembles human FucT V and VI rather than other known FucTs. N- ethylmaleimide, an inhibitor of several human FucTs, had no effect on the activity of the schistosomal alpha3-FucT, whereas GDP-beta-S was strongly inhibitory. Large scale incubations were carried out with Galbeta1-->4GlcNAc, GalNAcbeta1-->4GlcNAcbeta-O -(CH2)8COOCH3 and Fucalpha1-->3GlcNAcbeta1-->2Man as acceptor substrates and the products of the incubations were isolated using a sequence of chromatographic techniques. By methylation analysis and 2D-TOCSY and ROESY1H-NMR spectroscopy the products formed were shown to be Galbeta1-- >4[Fucalpha1-->2Fucalpha1-->3]GlcNAc, GalNAcbeta1-->4[Fucalpha1-- >2Fucalpha1-->3]GlcNAcbe ta-O-(CH2)8COOCH3, and Fucalpha1-->2Fucalpha1-- >3GlcNAcbeta1-->2Man, respectively. It is concluded that the alpha2- FucT and alpha3-FucT are involved in the biosynthesis of the (oligomeric) Lewisx sequences and the Fucalpha1-->2Fucalpha1-->3GlcNAc structural element that have been described on schistosomal glycoconjugates.