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961.
962.
Alexander E. Kissler Nina Pettersson Andreas Frölich Stephan J. Sigrist Beat Suter 《Developmental neurobiology》2009,69(6):365-377
Cyclin‐dependent kinase 5 (Cdk5) functions in postmitotic neuronal cells and play roles in cell differentiation, cell migration, axonal guidance, and synaptic function. Here, we demonstrate that Drosophila cdk5 is dispensable for adult viability and fertility, a feature that allows us to study its physiological function in the whole animal model. For the adult, cdk5 is needed for proper locomotion and flight performance. Larvae lacking cdk5 in the presynaptic tissue display abnormal crawling motion, and their neuromuscular junctions (NMJ) are elongated and contain a higher number of boutons that are smaller. As a result of these two counteracting effects, the total synaptic area/NMJ is similar to wild type, leading to normal synaptic transmission, indicating that a compensatory mechanism is capable of correcting the problem caused by the lack of cdk5. futsch, the Drosophila MAP1B homolog, is also involved in NMJ morphogenesis, and analysis of the NMJ phenotype of the double mutant futschK68; cdk5? indicates that cdk5 is epistatic to futsch in this process. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009 相似文献
963.
Alexandra Schwarz Stefan Helling Nicolas Collin Clarissa R. Teixeira Nora Medrano-Mercado Jen C. C. Hume Teresa C. Assump??o Katrin Marcus Christian Stephan Helmut E. Meyer José M. C. Ribeiro Peter F. Billingsley Jesus G. Valenzuela Jeremy M. Sternberg Günter A. Schaub 《PLoS neglected tropical diseases》2009,3(10)
Background
Triatomines are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease in Latin America. The most effective vector, Triatoma infestans, has been controlled successfully in much of Latin America using insecticide spraying. Though rarely undertaken, surveillance programs are necessary in order to identify new infestations and estimate the intensity of triatomine bug infestations in domestic and peridomestic habitats. Since hosts exposed to triatomines develop immune responses to salivary antigens, these responses can be evaluated for their usefulness as epidemiological markers to detect infestations of T. infestans.Methodology/Principal Findings
T. infestans salivary proteins were separated by 2D-gel electrophoresis and tested for their immunogenicity by Western blotting using sera from chickens and guinea pigs experimentally exposed to T. infestans. From five highly immunogenic protein spots, eight salivary proteins were identified by nano liquid chromatography-electrospray ionization-tandem mass spectrometry (nanoLC-ESI-MS/MS) and comparison to the protein sequences of the National Center for Biotechnology Information (NCBI) database and expressed sequence tags of a unidirectionally cloned salivary gland cDNA library from T. infestans combined with the NCBI yeast protein sub-database. The 14.6 kDa salivary protein [gi|149689094] was produced as recombinant protein (rTiSP14.6) in a mammalian cell expression system and recognized by all animal sera. The specificity of rTiSP14.6 was confirmed by the lack of reactivity to anti-mosquito and anti-sand fly saliva antibodies. However, rTiSP14.6 was recognized by sera from chickens exposed to four other triatomine species, Triatoma brasiliensis, T. sordida, Rhodnius prolixus, and Panstrongylus megistus and by sera of chickens from an endemic area of T. infestans and Chagas disease in Bolivia.Conclusions/Significance
The recombinant rTiSP14.6 is a suitable and promising epidemiological marker for detecting the presence of small numbers of different species of triatomines and could be developed for use as a new tool in surveillance programs, especially to corroborate vector elimination in Chagas disease vector control campaigns. 相似文献964.
Pieter Steenhuis Stephanie Herder Suyin Gelis Thomas Braulke Stephan Storch 《Traffic (Copenhagen, Denmark)》2010,11(7):987-1000
CLN7 is a polytopic lysosomal membrane protein deficient in variant late infantile neuronal ceroid lipofuscinosis, a neurodegenerative lysosomal storage disorder. In this study fluorescence protease protection assays and mutational analyses revealed the N‐ and C‐terminal tails of CLN7 in the cytosol and two N‐glycosylation sites at N371 and N376. Both partially and non‐glycosylated CLN7 were correctly transported to lysosomes. To identify lysosomal targeting motifs, we generated CD4‐chimera fused to the N‐ and C‐terminal domains of CLN7. Lysosomal localization of the chimeric proteins requires a consensus acidic dileucine‐based motif in the N‐terminus and two tandem tyrosine‐based signals in the C‐terminus. Mutation of these sorting motifs resulted in cell surface redistribution of CD4 chimeras. However, the dileucine‐based motif is of critical importance for lysosomal localization of the full‐length CLN7 in different cell lines. Cell surface biotinylation revealed that at equilibrium 22% of total CLN7 is localized at the plasma membrane. Mutation of the dileucine motif or the co‐expression of dominant‐negative mutant dynamin K44A led to a further increase of CLN7 at the plasma membrane. Our data demonstrate that CLN7 contains several cytoplasmic lysosomal targeting signals of which the N‐terminal dileucine‐based motif is required for the predominant lysosomal targeting along the indirect pathway and clathrin‐mediated endocytosis of CLN7. 相似文献
965.
Haubold M Weise A Stephan H Dünker N 《International journal of biological sciences》2010,6(7):700-715
Bone morphogenetic proteins (BMPs) - expressed in the developing retina - are known to be involved in the regulation of cell proliferation and apoptosis in several tumor entities. The objective of this study was to determine the role of the BMP4 pathway in retinoblastoma cells, which are absent in a functional retinoblastoma (RB1) gene. BMP receptors were detected in all retinoblastoma cell lines investigated. A correct transmission of BMP signaling via the Smad1/5/8 pathway could be demonstrated in WERI-Rb1 retinoblastoma cells and application of recombinant human BMP4 resulted in an increase in apoptosis, which to a large extend is caspase independent. Cell proliferation was not affected by BMP4 signaling, although the pRb-related proteins p107 and p130, contributing to the regulation of the same genes, are still expressed. WERI-Rb1 cells exhibit elevated endogenous levels of p21(CIP1) and p53, but we did not detect any increase in p53, p21(CIP1)or p27(KIP1) expression levels. Id proteins became, however, strongly up-regulated upon exogenous BMP4 treatment. Thus, RB1 loss in WERI-Rb1 cells is obviously not compensated for by pRb-independent (e.g. p53-dependent) cell cycle control mechanisms, preventing an anti-proliferative response to BMP4, which normally induces cell cycle arrest. 相似文献
966.
Andrew P. A. Oxley Mariana P. Lanfranconi Dieco Würdemann Stephan Ott Stefan Schreiber Terry J. McGenity Kenneth N. Timmis Balbina Nogales 《Environmental microbiology》2010,12(9):2398-2410
The human gastrointestinal tract microbiota, despite its key roles in health and disease, remains a diverse, variable and poorly understood entity. Current surveys reveal a multitude of undefined bacterial taxa and a low diversity of methanogenic archaea. In an analysis of the microbiota in colonic mucosal biopsies from patients with inflammatory bowel disease we found 16S rDNA sequences representing a phylogenetically rich diversity of halophilic archaea from the Halobacteriaceae (haloarchaea), including novel phylotypes. As the human colon is not considered a salty environment and haloarchaea are described as extreme halophiles, we evaluated and further discarded the possibility that these sequences originated from pre‐colonoscopy saline lavage solutions. Furthermore, aerobic enrichment cultures prepared from a patient biopsy at low salinity (2.5% NaCl) yielded haloarchaeal sequence types. Microscopic observation after fluorescence in situ hybridization provided evidence of the presence of viable archaeal cells in these cultures. These results prove the survival of haloarchaea in the digestive system and suggest that they may be members of the mucosal microbiota, even if present in low numbers in comparison with methanogenic archaea. Investigation of a potential physiological basis of this association may lead to new insights into gastrointestinal health and disease. 相似文献
967.
Eike R. Hrincius Viktor Wixler Thorsten Wolff Ralf Wagner Stephan Ludwig Christina Ehrhardt 《Cellular microbiology》2010,12(6):831-843
The non‐structural protein 1 (A/NS1) of influenza A viruses (IAV) harbours several src‐homology domain (SH) binding motifs that are required for interaction with cellular proteins. The SH3 binding motif at aa212‐217 [PPLPPK] of A/NS1 was shown to be essential for binding to the cellular adaptor proteins CRK and CRKL. Both regulate diverse cellular effector pathways, including activation of the MAP‐kinase JNK that in turn mediates antiviral responses to IAV infection. By studying functional consequences of A/NS1–CRK interaction we show here that A/NS1 binding to CRK contributes to suppression of the antiviral‐acting JNK–ATF2 pathway. However, only IAV that encode an A/NS1‐protein harbouring the CRK/CRKL SH3 binding motif PPLPPK were attenuated upon downregulation of CRKI/II and CRKL, but not of CRKII alone. The PPLPPK site‐harbouring candidate strains could be discriminated from other strains by a pronounced viral activation of the JNK–ATF2 signalling module that was even further boosted upon knock‐down of CRKI/II. Interestingly, this enhanced JNK activation did not alter type‐I IFN‐expression, but rather resulted in increased levels of virus‐induced cell death. Our results imply that binding capacity of A/NS1 to CRK/CRKL has evolved in virus strains that over‐induce the antiviral acting JNK–ATF2 signalling module and helps to suppress the detrimental apoptosis promoting action of this pathway. 相似文献
968.
969.
Sylvia Schäffer Stephan Koblmüller Tobias Pfingstl Christian Sturmbauer Günther Krisper 《BMC evolutionary biology》2010,10(1):246
Background
The use of molecular genetic data in phylogenetic systematics has revolutionized this field of research in that several taxonomic groupings defined by traditional taxonomic approaches have been rejected by molecular data. The taxonomic classification of the oribatid mite group Circumdehiscentiae ("Higher Oribatida") is largely based on morphological characters and several different classification schemes, all based upon the validity of diagnostic morphological characters, have been proposed by various authors. The aims of this study were to test the appropriateness of the current taxonomic classification schemes for the Circumdehiscentiae and to trace the evolution of the main diagnostic traits (the four nymphal traits scalps, centrodorsal setae, sclerits and wrinkled cuticle plus octotaxic system and pteromorphs both in adults) on the basis of a molecular phylogenetic hypothesis by means of parsimony, likelihood and Bayesian approaches. 相似文献970.
Christos Rumbos Stephan Reimann Sebastian Kiewnick Richard A. Sikora 《Biocontrol Science and Technology》2006,16(9):981-986
The interactions of Paecilomyces lilacinus strain 251 with the arbuscular mycorrhizal fungus Glomus intraradices and their significance for the control of Meloidogyne incognita on tomato were investigated in greenhouse experiments. Application of P. lilacinus had no effect on the frequency and intensity of tomato root colonization by G. intraradices. Likewise, the decline of the nematophagous fungus densities after single application in soil was not affected by the presence of the mycorrhizal fungus. Single application of P. lilacinus, as pre-planting soil treatment, resulted in significant reduction of nematode damage. In contrast, mycorrhizal inoculation did not provide sufficient biocontrol. Combined application of the two agents did not enhance root protection compared to single treatments. Double treatment of mycorrhized seedlings with P. lilacinus, as seedling drench and pre-planting soil treatment, 4 and 1 week before transplanting, respectively, resulted in the highest reduction of the nematode damage. These results indicate the potential of the commercial P. lilacinus strain 251 and mycorrhiza for integration in nematode control strategies. 相似文献