Slow-wave fluctuations in craniosacral space: hemo-liquorodynamic conception of origin

In the paper, the mechanism of forming of rhythmic slow-wave fluctuations in craniospinal cavity was investigated. In five young healthy persons, at rest and under voluntary respiration arrest test, the bioimpedansograms of head and lumbosacral part of vertebral column were synchronously registered as these recordings reflect the changes of relationships between blood/CSF volumes in cranial and lumbosacral regions, respectively. The recordings were subjected to frequency and spectral computer analysis (PC Macintosh G-4, Chart 5.2. software). The rapid (pulsatile) as well as slow and counter-directed waves (frequency 6-10 cycles/min) of these processes were revealed in cranial and lumbosacral regions. The data obtained suggest the CSF dynamic concept of origin of the craniosacral rhythm. The pulse and slow-frequency oscillations of the cerebral vessels tone initiate corresponding intracranial pressure waves, and the latter are the motivating forces for to-and-fro CSF shifts in caudal direction. This mechanism is accompanied by tonic contractions of lumbar muscles and sacrum movements, and it is manually perceptible as a craniosacral rhythm.     

Impaired embryonic haematopoiesis yet normal arterial development in the absence of the Notch ligand Jagged1

Specific deletion of Notch1 and RBPjkappa in the mouse results in abrogation of definitive haematopoiesis concomitant with the loss of arterial identity at embryonic stage. As prior arterial determination is likely to be required for the generation of embryonic haematopoiesis, it is difficult to establish the specific haematopoietic role of Notch in these mutants. By analysing different Notch-ligand-null embryos, we now show that Jagged1 is not required for the establishment of the arterial fate but it is required for the correct execution of the definitive haematopoietic programme, including expression of GATA2 in the dorsal aorta. Moreover, successful haematopoietic rescue of the Jagged1-null AGM cells was obtained by culturing them with Jagged1-expressing stromal cells or by lentiviral-mediated transduction of the GATA2 gene. Taken together, our results indicate that Jagged1-mediated activation of Notch1 is responsible for regulating GATA2 expression in the AGM, which in turn is essential for definitive haematopoiesis in the mouse.     

西藏白菜型油菜遗传多样性的RAPD分析

通过利用22个10bp随机引物对来自西藏高原地区107份白菜型油菜种质资源材料的PAPD分析,探讨了西藏白菜型油菜品种之间的遗传分化关系,结果表明：（1）供试的107份材料共产生236条谱带,其中210条谱带有多态性,占88．98％,说明白菜型油菜在西藏高原地区具有较丰富的遗传多样性;（2）根据引物扩增出的DNA指纹图谱,运用UPGMA分析法,在遗传距离为0．078处,可将供试的107份白菜型油菜划分为11个类群,发现来自于同一地区或气候相似区的品种往往聚在一起,表明西藏高原白菜型油菜品种的相似性与其原产地的地理,气候背景密切相关,并在此基础上,结合西藏高原农业发展历史,气候背景以及地形地貌特点和植物地理学,植物区系学,植物进化论等方面的综合分析,提出西藏高原是世界白菜型油菜起源地的观点。     

Comodulation of CXCR4 and CD26 in human lymphocytes

We provide convergent and multiple evidence for a CD26/CXCR4 interaction. Thus, CD26 codistributes with CXCR4, and both coimmunoprecipitate from membranes of T (CD4(+)) and B (CD4(-)) cell lines. Upon induction with stromal cell-derived factor 1alpha (SDF-1alpha), CD26 is cointernalized with CXCR4. CXCR4-mediated down-regulation of CD26 is not induced by antagonists or human immunodeficiency virus (HIV)-1 gp120. SDF-1alpha-mediated down-regulation of CD26 is not blocked by pertussis toxin but does not occur in cells expressing mutant CXCR4 receptors unable to internalize. Codistribution and cointernalization also occurs in peripheral blood lymphocytes. Since CD26 is a cell surface endopeptidase that has the capacity to cleave SDF-1alpha, the CXCR4.CD26 complex is likely a functional unit in which CD26 may directly modulate SDF-1alpha-induced chemotaxis and antiviral capacity. CD26 anchors adenosine deaminase (ADA) to the lymphocyte cell surface, and this interaction is blocked by HIV-1 gp120. Here we demonstrate that gp120 interacts with CD26 and that gp120-mediated disruption of ADA/CD26 interaction is a consequence of a first interaction of gp120 with a domain different from the ADA binding site. SDF-1alpha and gp120 induce the appearance of pseudopodia in which CD26 and CXCR4 colocalize and in which ADA is not present. The physical association of CXCR4 and CD26, direct or part of a supramolecular structure, suggests a role on the function of the immune system and the pathophysiology of HIV infection.     

Metabotropic glutamate 1alpha and adenosine A1 receptors assemble into functionally interacting complexes

Recently, evidence has emerged that seven transmembrane G protein-coupled receptors may be present as homo- and heteromers in the plasma membrane. Here we describe a new molecular and functional interaction between two functionally unrelated types of G protein-coupled receptors, namely the metabotropic glutamate type 1alpha (mGlu(1alpha) receptor) and the adenosine A1 receptors in cerebellum, primary cortical neurons, and heterologous transfected cells. Co-immunoprecipitation experiments showed a close and subtype-specific interaction between mGlu(1alpha) and A1 receptors in both rat cerebellar synaptosomes and co-transfected HEK-293 cells. By using transiently transfected HEK-293 cells a synergy between mGlu(1alpha) and A1 receptors in receptor-evoked [Ca(2+)](i) signaling has been shown. In primary cultures of cortical neurons we observed a high degree of co-localization of the two receptors, and excitotoxicity experiments in these cultures also indicate that mGlu(1alpha) and A1 receptors are functionally related. Our results provide a molecular basis for adenosine/glutamate receptors cross-talk and open new perspectives for the development of novel agents to treat neuropsychiatric disorders in which abnormal glutamatergic neurotransmission is involved.     

The closed/open model for lipase activation. Addressing intermediate active forms of fungal enzymes by trapping of conformers in water-restricted environments

The behavior of prototypic fungal lipases in a water-restricted environment has been investigated by exploiting the reported experimental strategy that allows the trapping (freeze-drying) of the enzyme in the conformation present in aqueous solution and to subsequently assay it in nonaqueous media [Mingarro, I., Abad, C., and Braco, L. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 3308-3312]. We now report, using simple esterification as well as acidolysis (triglycerides as substrates) as nonaqueous model reactions, that the presence of a detergent (n-octyl-beta-glucopyranoside) in the freeze-drying buffer, at concentrations below the critical micellar concentration, generates different catalytically active (kinetically trapped) conformational states of the enzyme. These activated forms exquisitely discriminate between short- and long-chain fatty acids, suggesting that they can be correlated with intermediate conformations of the protein sufficiently open to permit the access of relatively small but not large substrates. Additional data obtained from aqueous solution activity measurements in the presence of detergent revealed that the fungal lipase retains an active conformation induced by high detergent concentration (30 mM) for a long period of time, a 'memory effect', which is stabilized in the absence of a well-defined interface by few detergent molecules. Together these results provide support to a model of lipase action involving several equilibrium states (closed, intermediate, and open), which can be modulated by the composition of the microenvironment, i.e., by the detergent concentration.     

The effect of the indomethacin on phosphodiesterase inhibitors mediated responses in isolated trachea preparations

The aim of this study was to investigate the effects of indomethacin alone and with phosphodiesterase (PDE) inhibitory agents (rolipram, theophylline) on the isolated trachea preparations from control and ovalbumin sensitized guinea-pigs. Adult male guinea-pigs, weighing 300-350 g, were randomly allocated to 2 experimental groups each consisting of 12 animals. Guinea-pigs were sensitized by i.m. injections of 0.35 ml of a 5% (w/v) ovalbumin/saline solution into each thigh (0.7 ml total) on days 1 and 4. Tissues were first contracted with a submaximal concentration of histamine (10(-6) M). We tested the effects of indomethacin (10(-7)-10(-4) M) on the resting tension and precontracted with histamine on the isolated trachea preparations from control and ovalbumin sensitized guinea-pigs. We also tested the effects of the rolipram, theophylline and isoproterenol isolated trachea preparations precontracted with histamine in indomethacin incubated or non-incubated groups. We found that the relaxant effects of rolipram and theophylline increased, but not of isoproterenol, in the presence of indomethacin in isolated trachea preparations precontracted from control and ovalbumin-sensitized guinea-pigs. In the presence of indomethacin there was no difference in relaxant responses between both groups. Therefore, we concluded that the increased relaxant responses may be due to inhibitor effect of this agent on PDE isoenzymes.     

Comparative study of the effectiveness of HBcAg presentation to the immune system using attenuated Salmonella strains, serovars S.enteritidis and S.typhimurium

In this work the results of obtaining HBcAg-producing attenuated Salmonella strains, serovars S. enteritidis and S. typhimurium, and their comparative study is presented. As revealed in this study, attenuated S. enteritidis strain E-23 and S. typhimurium strain T-10, producing HBcAg, induce cell-mediated and humoral immune response to HBcAg after injected into anovals. After injection S. typhimurium strain T-10 induces a much higher titer of specific antibodies than S. enteritidis strain E-23. The level of specific antibodies induced by recombinant HBcAg seems to correlate with the capacity of salmonellae for survival inside macroorganisms.     

Hydrocarbon-binding peptides from bean plant lectins in connection with various host specific macrosymbionts during development of symbiosis with rhizobium bacteria

The nucleotide sequences of 280-360-bp domains of lectin genes from 20 legume species belonging to 17 genera have been determined. A computer analysis of the sequences has been performed with the LASERGENE package. Based on this analysis, we constructed the phylogenetic tree of the lectins, which reflects their phylogenetic and evolutionary relationships, and predicted the amino-acid sequences of the corresponding protein domains. Features of the structure of the hydrocarbon-binding lectin domains were elucidated in some species of legume genera from the temperate climatic zone. The domains were highly variable and contained the consensus sequence AspTrePheXxxAsxXxxXxxTrpAspProXxxXxxIns/DelArgHis bearing the bulk of amino acid replacements, insertions, and deletions. An association between legume groups (including species from different genera and tribes) symbiotic with the same rhizobium species and the similarity between the hydrocarbon-binding domains of lectins from these plants was found.