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41.
42.
ADELA GONZÁLEZ-MEGÍAS ROSA MENÉNDEZ† DAVID ROY‡ TOM BRERETON§ CHRIS D. THOMAS¶ 《Global Change Biology》2008,14(7):1464-1474
Changes in the abundance and distribution of individual species have been widely documented in Britain and other countries in recent decades, but little has been done to determine changes in community composition over broad geographic areas. Here, we studied species turnover in 51 butterfly assemblages in Britain since 1976, examining extinction and colonisation events together with variation in the abundances of the species. We showed that the species turnover that occurred over 20 years in Britain was associated with colonisation and extinction events and also with variability in the abundance of the species. These changes in community composition differed according to the habitat requirements of the species and their previous distributions, being more evident for habitat specialists and for southerly distributed species. Colonising species often became abundant components of the communities they joined, although this was more evident for generalist than for specialist species. The abundance of species following their arrival, increased with time since colonisation. Species turnover associated with southerly species expanding northwards is consistent with being a response to climate change. The results suggest that climate- and habitat-driven changes in the identity and abundance of species within communities are widespread, and probably ubiquitous. Similar changes are likely to be occurring in other groups of organisms that are similarly undertaking major range shifts associated with climate change. 相似文献
43.
Siu T Li Y Nagasawa J Liang J Tehrani L Chua P Jones RE Defeo-Jones D Barnett SF Robinson RG 《Bioorganic & medicinal chemistry letters》2008,18(14):4191-4194
This letter details the attenuation of hERG in a class of Akt inhibitors through heteroatom insertions into aromatic rings. The development of a cell-active dual Akt 1 and 2 inhibitors devoid of hERG activity is discussed using structure–activity relationships. 相似文献
44.
Density functional theory (DFT) calculations were performed at the B3LYP level with a 6-311++G(d,p) basis set to systematically explore the geometrical multiplicity and binding strength for complexes formed by Li+, Na+, and K+ with cytidine and 2′-deoxycytidine. All computational studies indicate that the metal ion affinity (MIA) decreases from Li+ to Na+ and K+ for cytosine nucleosides. For example, for cytidine the affinity for the above metal ions are 79.5, 55.2, and 41.8 and for 2′-deoxycytidine, 82.8, 57.4, and 42.2 kcal/mol, respectively. It is also interesting to mention that linear correlations between calculated MIA values and the atomic numbers (Z) of the above metal ions were found. The influence of metal cationization on the coordination modes and the strength of the N-glycosidic bond in cytosine nucleosides have been studied. In all cases, the N1-C1′ bond distance changes upon introducing a positive charge in the nucleosides. It has been found that metal binding significantly changes the values of the phase angle of pseudorotation P in the sugar unit of these nucleosides. With respect to the sugar ring, metal binding changes the values of the glycosyl torsion angle and sugar ring conformation. The present calculations in the gas phase provide the first clues on the intrinsic chemistry of these systems and may be of value for studies of the influence of metal cations on the conformational behavior and function of nucleic acids. 相似文献
45.
Vahid Molla Kazemiha Mohammad Ali Shokrgozar Mohammad Reza Arabestani Morteza Shojaei Moghadam Shahram Azari Susan Maleki Amir Amanzadeh Mahmood Jeddi Tehrani Fazel Shokri 《Cytotechnology》2009,61(3):117-124
A total of 200 cell lines including different human, monkey, mice, hamster and rat cell types were examined for mycoplasma
infection status. PCR assay using generic-specific universal primers showed that 40 (20%) of the cell lines are contaminated
with mycoplasma. Employment of species-specific primers within these infected cell lines revealed infection with M. hyorhinis (42.5%), M. fermentas (37.5%), M. arginini (37.5%), M. orale (12.5%) and A. laidlawii (7.5%). A number of the cultures were coinfected with 2 or 3 different species. Contaminated samples were treated with BM-Cyclin,
Ciprofloxacin and mycoplasma removal agent (MRA). Mycoplasma eradication was subsequently checked by PCR following 2 weeks
continuous culture of treated cells in antibiotic free culture medium. Mycoplasmal infections were eradicated in 100, 70 and
42% of infected cell lines when the samples were treated with BM-Cyclin, MRA and Ciprofloxacin, respectively. However, 12%
(BM-Cyclin), 62.5% (MRA) and 82.5% (Ciprofloxacin) of mycoplasma regrowth was observed 4 months after the treatment. Notably,
the risk of spontaneous culture death was 17.5, 12.5 and 0% for BM-Cyclin, MRA and Ciprofloxacin, respectively. 相似文献
46.
Sex and rank in competitive brood hierarchies influence stress levels in nestlings of a sexually dimorphic bird 总被引:1,自引:0,他引:1
GUILLERMO BLANCO OSCAR FRÍAS JAVIER MARTÍNEZ JESÚS A. LEMUS RUBEN MERINO BEGOÑA JIMÉNEZ 《Biological journal of the Linnean Society. Linnean Society of London》2006,88(3):383-390
Studies of sibling competition within brood hierarchies have rarely assessed simultaneously the effects of sex and rank in the brood hierarchy on traits other than offspring mortality and differential growth. We studied the expression of heat-shock proteins (Hsps) to assess the physiological stress response to different combinations of sex and position within competitive brood hierarchies in the black kite Milvus migrans (Bodd.), a sexually dimorphic raptor showing facultative siblicide. Senior males showed higher stress levels than did senior females and younger siblings of each sex as revealed by Hsp60 values. The analysis of Hsp70 levels indicated that nestlings from broods in which the senior chick was a male showed higher stress levels than did nestlings from broods in which the senior chick was a female. In addition, levels of Hsp60 were related negatively to nutritional condition expressed as levels of plasmatic albumin. This suggests that the sex of senior chicks may be key in determining their stress level and that of their siblings, which is probably associated with sibling competition by fighting within brood hierarchies. The comparatively higher stress levels of senior males (and their siblings) may be a consequence of their ability to exploit their potential advantage from being the head start while avoiding a possible competitive disadvantage from being the smaller sex, independent of environmental conditions determining the probability of brood reduction. Differential stress levels depending on sex and rank in the brood hierarchy may be a consequence of parental control of offspring behaviour through differential resource allocation (e.g. yolk androgens) or it may reflect adaptations of particular chicks (senior males) to enhance their competitive ability within brood hierarchies. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 383–390. 相似文献
47.
48.
Mohammad Ali Assarehzadegan Mojtaba Sankian Farahzad Jabbari Mohsen Tehrani Reza Falak AbdolReza Varasteh 《Molecular biology reports》2011,38(1):65-73
Salsola kali pollen is a common cause of pollinosis during summer and early fall in desert and semi-desert regions. The aim of this study
was the identification and characterization of Sal k 3, a new allergen from S. kali pollen. S. kali pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting using twelve
S. kali allergic patients. Protein identification was carried out by the means of mass spectrometry. Using degenerated primers, two
DNA fragments encoding N- and C-terminal domain of Sal k 3 were amplified by PCR, then cloned into the PTZ57R/T vector and
sequenced. The open reading frame of Sal k 3 fragments were subcloned in the pET-32b(+) vector, expressed in E. coli, and purified by Ni2+ affinity chromatography. The IgE-binding capacity of rSal k 3 fragments was then studied by IgE-immunoblotting, inhibition
assays, and skin prick tests. A 45-kDa allergen was identified as a fragment of the cobalamin-independent methionine synthase
(MetE) by mass spectrometry and was detected in the sera of 8/12 (66.6%) of S. kali allergic patients. Moreover, inhibition assays demonstrated that the purified rSal k 3 fragments were similar to their counterparts
in the crude extract. Sal k 3 represents a new allergen of S. kali pollen and seems to be an important allergenic compound in S. kali pollen. 相似文献
49.
Mohammad H. Jalilian Tehrani Constance J. Clancey Eugene M. Barnes Jr. 《Journal of neurochemistry》1985,45(4):1311-1314
Specific binding of [35S]t-butylbicyclophosphorothionate (TBPS) to membranes from cerebral hemispheres of adult rat and chicken was determined over a range of radioligand concentrations from 0.25 to 500 nM. Scatchard plots of these data were curvilinear and nonlinear regression analysis indicated binding to two sites that differ in affinity. For rat cerebrum, KD(1) = 1.15 nM, Bmax(1) = 0.085 pmol/mg; KD(2) = 232 nM, Bmax(2) = 16.9 pmol/mg. For chicken cerebrum, KD(1) = 1.39 nM, Bmax(1) = 0.111 pmol/mg; KD(2) = 166 nM, Bmax(2) = 17.6 pmol/mg. This multiplicity of [35S]TBPS binding was further confirmed when unlabeled TBPS or picrotoxinin displaced radioligand. The displacement curves were biphasic and yielded Hill coefficients from 0.65 to 0.70. These displacement curves were also resolved into two components with distinct IC50 values for unlabeled TBPS (rat, 1.55 and 271 nM; chicken, 2.40 and 224 nM). The IC50 values were similar to the dissociation constants obtained from equilibrium binding measurements. 相似文献
50.
Gregory D. Ferguson Mercedes Delgado Veronique Plantevin-Krenitsky Kristen Jensen-Pergakes R. J. Bates Sanaa Torres Maria Celeridad Heather Brown Kelven Burnett Lisa Nadolny Lida Tehrani Garrick Packard Barbra Pagarigan Jason Haelewyn Trish Nguyen Li Xu Yang Tang Matthew Hickman Frans Baculi Steven Pierce Keiji Miyazawa Pilgrim Jackson Philip Chamberlain Laurie LeBrun Weilin Xie Brydon Bennett Kate Blease 《PloS one》2016,11(1)
Autoantibodies and the immunoreceptors to which they bind can contribute to the pathogenesis of autoimmune diseases such as rheumatoid arthritis (RA). Spleen Tyrosine Kinase (Syk) is a non-receptor tyrosine kinase with a central role in immunoreceptor (FcR) signaling and immune cell functionality. Syk kinase inhibitors have activity in antibody-dependent immune cell activation assays, in preclinical models of arthritis, and have progressed into clinical trials for RA and other autoimmune diseases. Here we describe the characterization of a novel triazolopyridine-based Syk kinase inhibitor, CC-509. This compound is a potent inhibitor of purified Syk enzyme, FcR-dependent and FcR-independent signaling in primary immune cells, and basophil activation in human whole blood. CC-509 is moderately selective across the kinome and against other non-kinase enzymes or receptors. Importantly, CC-509 was optimized away from and has modest activity against cellular KDR and Jak2, kinases that when inhibited in a preclinical and clinical setting may promote hypertension and neutropenia, respectively. In addition, CC-509 is orally bioavailable and displays dose-dependent efficacy in two rodent models of immune-inflammatory disease. In passive cutaneous anaphylaxis (PCA), CC-509 significantly inhibited skin edema. Moreover, CC-509 significantly reduced paw swelling and the tissue levels of pro-inflammatory cytokines RANTES and MIP-1α in the collagen-induced arthritis (CIA) model. In summary, CC-509 is a potent, moderately selective, and efficacious inhibitor of Syk that has a differentiated profile when compared to other Syk compounds that have progressed into the clinic for RA. 相似文献