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81.
82.
Mammalian transforming growth factor beta1 activated after ingestion by Anopheles stephensi modulates mosquito immunity 下载免费PDF全文
Luckhart S Crampton AL Zamora R Lieber MJ Dos Santos PC Peterson TM Emmith N Lim J Wink DA Vodovotz Y 《Infection and immunity》2003,71(6):3000-3009
During the process of bloodfeeding by Anopheles stephensi, mammalian latent transforming growth factor beta1 (TGF-beta1) is ingested and activated rapidly in the mosquito midgut. Activation may involve heme and nitric oxide (NO), agents released in the midgut during blood digestion and catalysis of L-arginine oxidation by A. stephensi NO synthase (AsNOS). Active TGF-beta1 persists in the mosquito midgut to extended times postingestion and is recognized by mosquito cells as a cytokine. In a manner analogous to the regulation of vertebrate inducible NO synthase and malaria parasite (Plasmodium) infection in mammals by TGF-beta1, TGF-beta1 regulates AsNOS expression and Plasmodium development in A. stephensi. Together, these observations indicate that, through conserved immunological cross talk, mammalian and mosquito immune systems interface with each other to influence the cycle of Plasmodium development. 相似文献
83.
Viguié F Aboura A Bouscary D Guesnu M Baumelou E Dreyfus F Casadevall N Tachdjian G 《Cancer Genetics and Cytogenetics》2002,138(1):80-84
The bone marrow karyotypes of three patients with acute myelocytic leukemia (AML) or myelodysplastic syndrome (MDS) were studied at diagnosis and revealed, multiple copies of the same chromosomal anomaly, considered as psu idic(21)(q22) associated with other rearrangement(s). The karyotype of a fourth patient with MDS in transformation showed one copy of a dicentric marker presumably derived from a similar psu idic(21) by (tandem?) interstitial amplification of part of its structure, resembling a "homogeneous staining region", and described as der(21)psu idic(21)(q22)hsr(21)(q22). This rearrangement, previously described in isolated cases only, might be considered as recurrent in AML/MDS and associated with an unfavorable prognosis. It is most probably a secondary change, because it was never observed as sole abnormality and the main association, as for trisomy 21, was with del(5q). In the four cases, the number of partial supernumerary segmental 21pter-->21q22 copies, ranged from 2 to 10. The AML1 gene did not appear to be the common target of this amplification because this locus had been lost by the psu idic(21) in one patient 相似文献
84.
Claire Bihoreau Agns Heurtier Alain Enjalbert Nicole Corvaïa Armand Bensussan Laurent Degos Claude Kordon 《European journal of immunology》1991,21(11):2877-2882
A monoclonal antibody (OKT3) directed against the T cell receptor (TcR)/CD3 molecular complex, as well as a protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate, PMA) were added to a culture of tumoral Jurkat T cells, in order to precise the sequence of intracellular signals leading to T cell activation. The experiments were performed in the presence or in absence of various stimulators of adenylate cyclase (AC) such as forskolin (FK), cholera toxin (CT) or prostaglandin E2 (PGE2). OKT3 increased inositol phosphate (IP) production; in parallel, it induced a slight accumulation of cAMP. The effect was markedly potentiated in presence of FK or CT, and to a lesser extent in the presence of PGE2. FK stimulated adenylate cyclase of Jurkat cell membranes, but the effect was not potentiated by OKT3, suggesting that potentiation of cAMP accumulation requires intact cells and is not mediated by direct receptor coupling. On the other hand, elevated cAMP accumulation induced a negative feedback on IP production. The effect of OKT3 on cAMP was mimicked by A23187, a Ca2+ ionophore, and abolished in the absence of extracellular Ca2+. PMA had the same effect as OKT3 on basal or FK- and CT-induced accumulation of cAMP. In contrast, it inhibited the PGE2 effect on the cyclic nucleotide. After desensitization of PKC by pretreatment with a high concentration of PMA, the phorbol ester was no longer effective. Under those conditions, facilitation by OKT3 of FK-induced accumulation of cAMP was preserved, whereas potentiation by the monoclonal antibody of the PGE2 stimulation of AC was even enhanced. The data indicate that cAMP accumulation indirectly elicited by phospholipase C activation is, at least partly, mediated by IP-dependent Ca2+ mobilization, while PKC is preferentially effective as an inhibitor of PGE2 stimulation. 相似文献
85.
86.
Oviposition site selection has been recognized as critical both for the survival and population dynamics of mosquitoes. Volatile substances released from larval habitats have been implicated as potential olfactory cues mediating oviposition. In our continuing studies of cues involved in oviposition site selection, we collected material from the larval habitats of Anopheles albimanus Wiedemann and Anopheles vestitipennis Dyar & Knab, i.e., cyanobacterial mats and Typha domingensis Pers. litter, respectively. The volatile compounds were extracted by freeze-drying the material and trapping the volatilized material on a -55 degrees C titanium condenser. For oviposition trials conducted with wild-caught females, the tested volatile materials were pipetted onto filters floating on the surface of distilled water in Teflon beakers that were placed within oviposition cages. For both species, volatile materials in low concentrations increased oviposition, assessed as egg density, whereas there was a shift to reduced oviposition at higher concentrations. Volatile effect was strongly habitat/species-specific as shown by reciprocal treatment tests. 相似文献
87.
Teun P De Boer Bart Kok Kirsten I E Neuteboom Nicole Spieker Jochum De Graaf Olivier H J Destrée Martin B Rook Toon A B Van Veen Habo J Jongsma Marc A Vos Jacques M T De Bakker Marcel A G Van Der Heyden 《Developmental dynamics》2005,233(3):864-871
Connexin-containing gap junctions play an essential role in vertebrate development. More than 20 connexin isoforms have been identified in mammals. However, the number identified in Xenopus trails with only six isoforms described. Here, identification of a new connexin isoform from Xenopus laevis is described. Connexin40.4 was found by screening expressed sequence tag databases and carrying out polymerase chain reaction on genomic DNA. This new connexin has limited amino acid identity with mammalian (<50%) connexins, but conservation is higher (approximately 62%) with fish. During Xenopus laevis development, connexin40.4 was first expressed after the mid-blastula transition. There was prominent expression in the presomitic paraxial mesoderm and later in the developing somites. In adult frogs, expression was detected in kidney and stomach as well as in brain, heart, and skeletal muscle. Ectopic expression of connexin40.4 in HEK293 cells, resulted in formation of gap junction like structures at the cell interfaces. Similar ectopic expression in neural N2A cells resulted in functional electrical coupling, displaying mild, asymmetric voltage dependence. We thus cloned a novel connexin from Xenopus laevis, strongly expressed in developing somites, with no apparent orthologue in mammals. 相似文献
88.
Nathalie Thieblemont Laurence Weiss Hoss M. Sadeghi Claudia Estcourt Nicole Haeffner-Cavaillon 《European journal of immunology》1995,25(12):3418-3424
Infection with the human immunodeficiency virus HIV-1 is associated with the expansion of a CD14lowCD16high monocyte subset in peripheral blood. This subset, which represents a minor subpopulation of monocytes in healthy individuals, increases during HIV infection and, in patients with AIDS, may represent up to 40% of the total circulating monocyte cell population. The CD14lowCD16high circulating monocytes co-express MAX.1, p150,95 and HLADR which are typical of tissue macrophage markers. These cells also express higher levels of intracellular interleukin (IL)-1α and tumor necrosis factor (TNF)-α than the CD14highCD16low monocyte population from the same patients. The CD14lowCD16high cells also express low levels of CD35, CD11a and CD4 in common with normal monocytes. When cultured in vitro, monocytes from HIV-seropositive individuals differentiated within a few hours into an elongated fibroblastoid shape characteristic of migratory cells. Our results suggest that the expansion of the CD14lowCD16high monocyte subset, which produce high amounts of TNF-α and IL-1α, may participate in the immune dysfunction observed during HIV infection. 相似文献
89.
The geographical correlations between the incidence of various cancers and the HLA and ABO antigen frequencies are studied. There is, for example, a positive correlation between breast and colorectal carcinoma and AI, B8 and B12 antigens, and a negative one between prostate carcinoma and B12. The role of the HLA system itself or other genes involved in these associations is discussed. This study gives some evidence of a possible genetic background of susceptibility or resistance to cancer. 相似文献
90.
Jannot AS Meziani R Bertrand G Gérard B Descamps V Archimbaud A Picard C Ollivaud L Basset-Seguin N Kerob D Lanternier G Lebbe C Saiag P Crickx B Clerget-Darpoux F Grandchamp B Soufir N Melan-Cohort 《European journal of human genetics : EJHG》2005,13(8):913-920
The occuloalbinism 2 (OCA2) gene, localized at 15q11, encodes a melanosomal transmembrane protein that is involved in the most common form of human occulo-cutaneous albinism, a human genetic disorder characterized by fair pigmentation and susceptibility to skin cancer. We wondered whether allele variations at this locus could influence susceptibility to malignant melanoma (MM). In all, 10 intragenic single-nucleotide polymorphisms (SNPs) were genotyped in 113 patients with melanomas and in 105 Caucasian control subjects with no personal or family history of skin cancer. By comparing allelic distribution between cases and controls, we show that MM and OCA2 are associated (p value=0.030 after correction for multiple testing). Then, a recently developed strategy, the 'combination test' enabled us to show that a combination formed by two SNPs was most strongly associated to MM, suggesting a possible interaction between intragenic SNPs. In addition, the role of OCA2 on MM risk was also detected using a logistic model taking into account the presence of variants of the melanocortin 1 receptor gene (MC1R, a key pigmentation gene) and all pigmentation characteristics as melanoma risk factors. Our data demonstrate that a second pigmentation gene, in addition to MC1R, is involved in genetic susceptibility to melanoma. 相似文献