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251.
Eyestalks of the palinuran species Jasus lalandii and Panulirus homarus, and the brachyuran species Carcinus maenas, were examined with antisera raised against purified crustacean hyperglycaemic hormone (cHH) of the astacidean species Homarus americanus and Procambarus bouvieri, as well as the brachyuran species Cancer pagurus. Other antisera used in this investigation were raised against purified moult-inhibiting hormone (MIH) of C. pagurus and vitellogenesis-inhibiting hormone (VIH) of H. americanus. Positive immunoreactions to all the antisera were localised in perikarya of the X-organ and the axon terminals in the sinus gland of all the crustaceans investigated. These results illustrate the existence of an immunological similarity, detectable at the immunocytochemical level, between the cHH/MIH/VIH neurohormones of the Astacidae, Palinura and Brachyura infraorders. Furthermore, results from consecutive tissue sections indicate that cHH, MIH and VIH are co-localised in a subpopulation of X-organ neurons. 相似文献
252.
TNF receptor 1-dependent beta cell toxicity as an effector pathway in autoimmune diabetes 总被引:9,自引:0,他引:9
Kägi D Ho A Odermatt B Zakarian A Ohashi PS Mak TW 《Journal of immunology (Baltimore, Md. : 1950)》1999,162(8):4598-4605
Autoimmune diabetes is characterized by a chronic progressive inflammatory autoimmune reaction that ultimately causes the selective elimination of pancreatic beta cells. To address the question of whether the cell death-inducing cytokines TNF and lymphotoxin alpha are involved in this process, we generated nonobese diabetic (NOD) mice that are deficient for TNF receptor 1 (TNFR1 or TNFRp55). Insulitis developed in these mice similarly to that in normal control NOD mice, but progression to diabetes was completely abrogated. Since this was probably due to the complex immunomodulatory effects of TNF and lymphotoxin alpha signaled via TNFR1 on lymphohemopoietic cells, adoptive transfer experiments with spleen cells from diabetic NOD mice were conducted. It was found that the absence of TNFR1 in recipients delayed diabetes induced by normal control and precluded diabetes induced by perforin-deficient spleen cells. In a CD8+ T cell-mediated model of diabetes, however, diabetes induced by adoptive transfer of TCR transgenic lymphocytic choriomeningitis virus glycoprotein-specific CD8+ T cells was not delayed by the absence of TNFR1 in recipient mice. Together with the described expression patterns of perforin and TNF in the mononuclear islet infiltrates of NOD mice, these results indicate that two diabetogenic effector mechanisms are delivered by distinct cell populations: CD8+ T cells lyse beta cells via perforin-dependent cytotoxicity, whereas CD4+ T cells, macrophages, and dendritic cells contribute to diabetes development via TNFR1-dependent beta cell toxicity. 相似文献
253.
254.
Plants have large families of proteins sharing a conserved eight-cysteine-motif (8CM) domain. The biological functions of
these proteins are largely unknown. EARLI1 is a cold responsive Arabidopsis gene that encodes a hybrid proline-rich protein (HyPRP) with a three-domain architecture:
a putative signal peptide at the N-terminus, a proline-rich domain (PRD) in the middle, and an 8CM domain at the C-terminus.
We report here that yeast cells expressing different EARLI1 genes had significantly higher rates of freezing survival than empty-vector transformed controls. Arabidopsis plants with
knocked down EARLI1 genes had an increased tendency for freezing-induced cellular damage. EARLI1-GFP fluorescence in transgenic plants and immunoblot
analyses using protoplasts suggested cell wall localization for EARLI1 proteins. Immunoblot analyses showed that EARLI1 proteins
form higher order complexes in plants, and that the PRD is a soluble and the 8CM an insoluble protein domain. We propose that
EARLI1 proteins have a bimodular architecture in which the PRD may interact with the cell wall and the 8CM domain with the
plasma membrane to protect the cells during freezing stress. 相似文献
255.
Gelatin zymography revealed the presence of proteolytic activity in conditioned medium (CM) from a serum-free, non-infected Spodoptera frugiperda, Sf9 insect cell culture. Two peptidase bands at about 49 and 39 kDa were detected and found to be proform and active form of the same enzyme. The 49-kDa form was visible on zymogram gels in samples of CM taken on days 4 and 5 of an Sf9 culture, while the 39-kDa form was seen on days 6 and 7. On basis of the inhibitor profile and substrate range, the enzyme was identified as an Sf9 homologue of cathepsin L, a papain-like cysteine peptidase. After lowering the pH of Sf9 CM to 3.5, an additional peptidase band at 22 kDa appeared. This peptidase showed the same inhibitor profile, substrate range and optimum pH (5.0) as the 39-kDa form, indicating that Sf9 cathepsin L has two active forms, at 39 and 22 kDa. Addition of the cysteine peptidase inhibitor E-64c to an Sf9 culture inhibited all proteolytic activities of Sf9 cathepsin L but did not influence the proliferation of Sf9 cells. 相似文献
256.
Parkkari T Myllymäki M Savinainen JR Saario SM Castillo-Meléndez JA Laitinen JT Nevalainen T Koskinen AM Järvinen T 《Bioorganic & medicinal chemistry letters》2006,16(9):2437-2440
Alpha-methylated analogues of the endogenous cannabinoid, 2-arachidonoyl glycerol (2-AG), were synthesized aiming to the improved enzymatic stability of 2-AG. In addition, the CB1 activity properties of fluoro derivatives of 2-AG were studied. The CB1 receptor activity was determined by the [35S]GTPgammaS binding assay, and the enzymatic stability of alpha-methylated analogues was determined in rat cerebellar membranes. The results indicate that even if the alpha-methylated 2-AG derivatives are slightly weaker CB1 receptor agonists than 2-AG, they are clearly more stable than 2-AG. In addition, the results showed that the replacement of the hydroxyl group(s) of 2-AG by fluorine does not improve the CB1 activity of 2-AG. 相似文献
257.
Summary Growth of hydroponically cultivated birch seedlings (Betula pendula Roth.) at sub- and supra-optimum potassium supply rates was investigated. Potassium was supplied either as a relative addition rate (r
k = 5, 10, 15 and 20% increase day-1) or as fixed concentrations (0.2, 3, 6, 12 and 15 mM) in the culture solution. After an acclimation period the growth rate of the seedlings in the suboptimum treatments reached values close to the treatment variable, the relative rate of K-addition. Deficiency symptoms, in the form of chlorosis and necroses along the leaf margins, developed initially in all suboptimum treatments, but very few new symptoms appeared once the seedlings had reached the phase of steady-state nutrition and growth. At supra-optimum K-supply levels, i.e. at 0.2–15 mM K in the culture solution, no symptoms of deficiency or toxicity developed, and the relative growth rate of the seedlings remained maximum. The relative growth rate of the seedlings was linearly related to the plant K-status for K contents ranging from 0.2 to 1.0% of dry weight (DW). At higher internal K-concentrations, 1.0–3.0% DW, no further increase in relative growth rate was achieved. A shortage of K resulted in a decrease in the net assimilation rate. This effect was counterbalanced by the absence of shift in he leaf weight ratio as well as by the production of relatively thin leaves. The fraction of dry matter allocated to roots decreased in K-limited plants, as did the leaf contents of soluble carbohydrates and starch. 相似文献
258.
Merete Fredholm Anne Katrine Winterø Knud Christensen Birte Kristensen Poul Bräuner Nielsen William Davies Alan Archibald 《Mammalian genome》1993,4(4):187-192
Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P<0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.The nucleotide sequence data reported in this paper have been submitted to GenBank and have been assigned the accession numbers listed in Table 1. 相似文献
259.
Schneider MR Dahlhoff M Horst D Hirschi B Trülzsch K Müller-Höcker J Vogelmann R Allgäuer M Gerhard M Steininger S Wolf E Kolligs FT 《PloS one》2010,5(12):e14325
Background
E-cadherin is a major component of adherens junctions. Impaired expression of E-cadherin in the small intestine and colon has been linked to a disturbed intestinal homeostasis and barrier function. Down-regulation of E-cadherin is associated with the pathogenesis of infections with enteropathogenic bacteria and Crohn''s disease.Methods and Findings
To genetically clarify the function of E-cadherin in intestinal homeostasis and maintenance of the epithelial defense line, the Cdh1 gene was conditionally inactivated in the mouse intestinal epithelium. Inactivation of the Cdh1 gene in the small intestine and colon resulted in bloody diarrhea associated with enhanced apoptosis and cell shedding, causing life-threatening disease within 6 days. Loss of E-cadherin led cells migrate faster along the crypt-villus axis and perturbed cellular differentiation. Maturation and positioning of goblet cells and Paneth cells, the main cell lineage of the intestinal innate immune system, was severely disturbed. The expression of anti-bacterial cryptidins was reduced and mice showed a deficiency in clearing enteropathogenic bacteria from the intestinal lumen.Conclusion
These results highlight the central function of E-cadherin in the maintenance of two components of the intestinal epithelial defense: E-cadherin is required for the proper function of the intestinal epithelial lining by providing mechanical integrity and is a prerequisite for the proper maturation of Paneth and goblet cells. 相似文献260.
Askoxylakis V Garcia-Boy R Rana S Krämer S Hebling U Mier W Altmann A Markert A Debus J Haberkorn U 《PloS one》2010,5(12):e15962
Carbonic anhydrase IX (CAIX) is a transmembrane enzyme found to be overexpressed in various tumors and associated with tumor hypoxia. Ligands binding this target may be used to visualize hypoxia, tumor manifestation or treat tumors by endoradiotherapy.