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31.
Foronda P Valladares B Rivera-Medina JA Figueruelo E Abreu N Casanova JC 《Parasite (Paris, France)》2004,11(3):311-316
The prevalence and intensity of the parasites from 50 wild doves (Columba livia) from the city of Santa Cruz de Tenerife, in the island of Tenerife (Canary Archipelago), were studied. The following ectoparasites were found in apparently healthy pigeons (prevalences are shown in percentage (%) and mean intensities with their standard deviations): the acari Dermanyssus gallinae (De Geer, 1778) (6, 241.0 +/- 138.9) and Tinaminyssus melloi Fain, 1962 (10%, 218.3 +/- 117.3); the louses, Columbicola columbae Linnaeus, 1758 (100%, 111.4 +/- 76.8) and Campanulotes bidentatus Scopoli, 1763 (94%, 48.4 +/- 26.6); and the pigeon fly, Pseudolynchia canariensis Macquart, 1839 (36%, 6.2 +/- 1.6). The endoparasites we found were: a haemoprotozoan species, Haemoproteus columbae Kruze, 1890 (82%, 14.8 +/- 10.3 per 1000); coccidian oocysts, Eimeria sp. (50%, 0.2 x 10(3) +/- 1.7 x 10(3) per gr); a cestode species Raillietina micracantha (Fuhrmann, 1909) López Neyra, 1947 (44%, 12.3 +/- 9.4); and four nematode species, Tetrameres (Tetrameres) fissispina (Diesing, 1861) Travassos, 1915 (4%, 99.5 +/- 34.1), Synhimantus (Dispharynx) spiralis (Molin, 1858) (8%, 46.8 +/- 11.6), Ascaridia columbae (Gmelin, 1790) Travassos, 1913 (40%, 8.4 +/- 8.8) and Aonchotheca sp. (18%, 6.0 +/- 3.1). Several species detected in our study can be pathogens for C. bollii and C. junoniae, which are endemic pigeons of the Canary Islands, considered endangered species. Parasites (ectoparasites, protozoa and helminths) of C. livia found in Tenerife and others from wild and farm birds in the island were considered as healthy controls. 相似文献
32.
The role of IL-12, IL-23 and IFN-gamma in immunity to viruses 总被引:2,自引:0,他引:2
IL-12, IL-23 and IFN-gamma form a loop and have been thought to play a crucial role against infectious viruses, which are the prototype of "intracellular" pathogens. In the last 10 years, the generation of knock-out (KO) mice for genes that control IL-12/IL-23-dependent IFN-gamma-dependent mediated immunity (STAT1, IFN-gammaR1, IFNgammaR2, IL-12p40 and IL-12Rbeta1) and the identification of patients with spontaneous germline mutations in these genes has led to a re-examination of the role of these cytokines in anti-viral immunity. We here review viral infections in mice and humans with genetic defects in the IL-12/IL-23-IFN-gamma axis. A comparison of the phenotypes observed in KO mice and deficient patients suggests that the human IL-12/IL-23-IFN-gamma axis plays a redundant role in immunity to most viruses, whereas its mouse counterparts play a more important role against several viruses. 相似文献
33.
Tremendous progress has been achieved in developmental, cellular and molecular immunology in the past 20 years, largely due to studies using the mouse as a model system and the arrival of molecular genetics. Immunology is now faced with a difficult challenge. What are the functions of the individual cells and molecules in achieving immunity to infection? Renewed interest in animal models of disease has provided considerable insight in this area, but such models of infection suffer from the inherent limitation of being experimental. In humans, the complex host-environment interaction occurs in natural, as opposed to experimental, conditions. The human model is therefore an indispensable complement to animal models, as it allows an observational genetic dissection of immunity to infection. 相似文献
34.
Floxed allele for conditional inactivation of the GABAB(1) gene 总被引:3,自引:0,他引:3
Haller C Casanova E Müller M Vacher CM Vigot R Doll T Barbieri S Gassmann M Bettler B 《Genesis (New York, N.Y. : 2000)》2004,40(3):125-130
GABA(B) receptors are the G-protein-coupled receptors for the neurotransmitter GABA. GABA(B) receptors are broadly expressed in the nervous system. Their complete absence in mice causes premature lethality or--when mice are viable--epilepsy, impaired memory, hyperalgesia, hypothermia, and hyperactivity. A spatially and temporally restricted loss of GABA(B) function would allow addressing how the absence of GABA(B) receptors leads to these diverse phenotypes. To permit a conditional gene inactivation, we flanked critical exons of the GABA(B(1)) gene with lox511 sites. GABA(B(1)) (lox511/lox511) mice exhibit normal levels of GABA(B(1)) protein, are fertile, and do not display any behavioral phenotype. We crossed GABA(B(1)) (lox511/lox511) with Cre-deleter mice to produce mice with an unrestricted GABA(B) receptor elimination. These GABA(B(1)) (-/-) mice no longer synthesize GABA(B(1)) protein and exhibit the expected behavioral abnormalities. The conditional GABA(B(1)) allele described here is therefore suitable for generating mice with a site- and time-specific loss of GABA(B) function. 相似文献
35.
36.
de la Fuente MT Casanova B Cantero E Hernández del Cerro M Garcia-Marco J Silva A Garcia-Pardo A 《Biochemical and biophysical research communications》2003,311(3):708-712
We recently showed that alpha4beta1 integrin induces B-cell chronic lymphocytic leukemia (B-CLL) cell resistance to fludarabine-induced apoptosis via upregulation of Bcl-xL. We have now studied whether p53 was involved in this response. Cells from five B-CLL patients with wild-type p53 determined by DNA sequencing, or from the EHEB cell line, cultured on the alpha4beta1 ligand H/89 during fludarabine treatment, showed significantly higher viability (P相似文献
37.
Morphogenesis of the Drosophila tracheal system relies on different signalling pathways that have distinct roles in specifying both the migration of the tracheal cells and the particular morphological features of the primary branches. The current view is that the tracheal cells are initially specified as an equivalent group of cells whose diversification depends on signals from the surrounding cells. In this work, we show that the tracheal primordia are already specified as distinct dorsal and ventral cell populations. This subdivision depends on the activity of the spalt (sal) gene and occurs prior to the activity of the signalling pathways that dictate the development of the primary branches. Finally, we show that the specification of these two distinct cell populations, which are not defined by cell lineage, are critical for proper tracheal patterning. These results indicate that tracheal patterning depends not only on signalling from surrounding cells but also in the different response of the tracheal cells depending on their allocation to the dorsal or ventral domains. 相似文献
38.
The use of site-specific recombinases enables the precise introduction of defined genetic mutations into the mouse genome. In theory, any deletion, point mutation, inversion or translocation can be modeled in mice. Because gene targeting is controlled both spatially and temporally, the function of a given gene can be studied in the desired cell types and at a specific time point. This 'genetic dissection' allows to define gene function in development, physiology or behavior. In this review, we focus on the technical possibilities of Cre and other site-specific recombinases but also discuss their limitations. 相似文献
39.
Casanova JE 《American journal of physiology. Gastrointestinal and liver physiology》2002,283(5):G1015-G1019
Migration of epithelial cells occurs in a variety of important biological processes including tissue morphogenesis, wound healing, and the metastasis of epithelial tumors. In some instances, the cells remain attached to each other and migrate together as a sheet, maintaining epithelial integrity. In others (e.g., metastasis), junctional complexes are disrupted and cells migrate individually. In both cases, motility involves the extension of membranous protrusions (filopodia and lamellipodia) in the direction of movement and the transient assembly and disassembly of integrin-mediated adhesions with the extracellular matrix. The driving force for these events is provided by regulated changes in the organization of the actin cytoskeleton, which are thought to be coordinated with alterations in intracellular membrane traffic. In this themes article, I review current hypotheses about how these processes are integrated and attempt to identify fruitful areas for future research. 相似文献
40.
Development times and mortality factors were investigated for populations of Aedes scapularis (Rondani) occurring in natural temporary ground pools in southeastern Brazil. Analysis of life tables by the key-factor method showed that mortality caused by desiccation of breeding sites was the principal factor accounting for fluctuations in population sizes throughout the study period. For cohorts that completed development, mortality attributed to predation by aquatic insects ranged from 68 to 96% and was the most important cause of death. In these cohorts, final population size was determined by the high mortality rates that occurred during the fourth larval instar and pupal stages; however, the key-factor best accounting for the population fluctuations was predation of fourth instar larvae. The short mean time of 7.1 days for synchronous development of the larvae and the lack of evidence of density-dependent mortality suggested that the A. scapularis populations were not strongly regulated and can attain relatively high densities. 相似文献