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991.
Franziska Volland-Voigt Achim Br?uning Oswaldo Ganzhi Thorsten Peters Hector Maza 《Trees - Structure and Function》2011,25(1):39-48
Stem diameter increments of the broadleaved deciduous tree species Tabebuia chrysantha were measured with high-resolution dendrometers in a tropical lower montane forest and in a dry forest in southern Ecuador,
the latter showing a distinct dry season. Those analyses were complemented by wood anatomical studies on regularly collected
microcores to determine the season of active cambial growth and the time of formation of annual growth boundaries. The length
of the cambial active period varied between 3 and 7 months at the tropical lower montane forest and 2 and 4 months in the
dry forest, respectively. During dry days, amplitudes of daily stem diameter variations correlated with vapour pressure deficit.
During October and November, inter-annual climate variations may lead to dry and sunny conditions in the tropical lower montane
forest, causing water deficit and stem diameter shrinkage in T. chrysantha. The results of the climate–growth analysis show a positive relationship between tree growth and rainfall as well as vapour
pressure deficit in certain periods of the year, indicating that rainfall plays a major role for tree growth. 相似文献
992.
Nuttall SD Wilkins ML Streltsov VA Pontes-Braz L Dolezal O Tran H Liu CQ 《Proteins》2011,79(4):1306-1317
One method of laboratory- or field-based testing for anthrax is detection of Bacillus anthracis spores by high-affinity, high specificity binding reagents. From a pool of monoclonal antibodies, we selected one such candidate (A4D11) with high affinity for tBclA, a truncated version of the B. anthracis exosporium protein BclA. Kinetic analysis utilising both standard and kinetic titration on a Biacore biosensor indicated antibody affinities in the 300 pM range for recombinant tBclA, and the A4D11 antibody was also re-formatted into scFv configuration with no loss of affinity. However, assays against B. anthracis and related Bacilli species showed limited binding of intact spores as well as significant cross-reactivity between species. These results were rationalized by determination of the three-dimensional crystallographic structure of the scFv-tBclA complex. A4D11 binds the side of the tBclA trimer, contacting a face of the antigen normally packed against adjacent trimers within the exosporium structure; this inter-spore interface is highly conserved between Bacilli species. Our results indicate the difficulty of generating a high-affinity antibody to differentiate between the highly conserved spore structures of closely related species, but suggest the possibility of future structure-based antibody design for this difficult target. 相似文献
993.
Dirk?T.?Hoekstra Heinrich?Volschenk Michelle?Collins Lynn?D.?McMasterEmail author 《Journal of applied phycology》2011,23(4):777-787
The presence of the anaerobic spore former Clostridium in Arthrospira platensis destined for human consumption is generally not assessed during quality assurance procedures. As this nutraceutical is administered
as complementary medicine to the immunocompromised, this study aimed to investigate the presence of these potential pathogens.
Anaerobic counts performed on tablets from a single manufacturer indicated an excess of 105 CFU/endospores g−1 tablet for three different A. platensis batches. Tests for coliforms for use as “indicators” of pathogens in the tablets were negative. Using classic culture techniques,
five species of Clostridium were isolated. Subsequent use of PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting of tablets showed a divergent
microbial population, with a predominance of anaerobic endospore formers, including Clostridium. Sequencing of a 1.5 kb 16S rDNA clone library and phylogenetic analyses of prominent operational taxonomic units confirmed
the presence of an additional five Clostridium spp. and other genera in the tablets. A composite molecular ladder, using 16S rRNA DGGE amplicons of 17 representative bacterial
species was constructed to assist in identifying anaerobes present in tablets sourced from three different A. platensis manufacturers. Results indicated that commercial A. platensis preparations were contaminated with potentially hazardous clostridia and other anaerobic species. Results suggest that certain
commercial A. platensis preparations require stringent microbial quality assurance measures to ensure safe use as a nutraceutical for the immunocompromised
and the general public. 相似文献
994.
McClure KJ Maher M Wu N Chaplan SR Eckert WA Lee DH Wickenden AD Hermann M Allison B Hawryluk N Breitenbucher JG Grice CA 《Bioorganic & medicinal chemistry letters》2011,21(18):5197-5201
The discovery of a series of novel, potent, and selective blockers of the cyclic nucleotide-modulated channel HCN1 is disclosed. Here we report an SAR study around a series of selective blockers of the HCN1 channel. Utilization of a high-throughput VIPR assay led to the identification of a novel series of 2,2-disubstituted indane derivatives, which had moderate selectivity and potency at HCN1. Optimization of this hit led to the identification of the potent, 1,1-disubstituted cyclohexane HCN1 blocker, 2-ethoxy-N-((1-(4-isopropylpiperazin-1-yl)cyclohexyl)methyl)benzamide. The work leading to the discovery of this compound is described herein. 相似文献
995.
Charruau P Fernandes C Orozco-Terwengel P Peters J Hunter L Ziaie H Jourabchian A Jowkar H Schaller G Ostrowski S Vercammen P Grange T Schlötterer C Kotze A Geigl EM Walzer C Burger PA 《Molecular ecology》2011,20(4):706-724
The cheetah (Acinonyx jubatus) has been described as a species with low levels of genetic variation. This has been suggested to be the consequence of a demographic bottleneck 10 000–12 000 years ago (ya) and also led to the assumption that only small genetic differences exist between the described subspecies. However, analysing mitochondrial DNA and microsatellites in cheetah samples from most of the historic range of the species we found relatively deep phylogeographic breaks between some of the investigated populations, and most of the methods assessed divergence time estimates predating the postulated bottleneck. Mitochondrial DNA monophyly and overall levels of genetic differentiation support the distinctiveness of Northern‐East African cheetahs (Acinonyx jubatus soemmeringii). Moreover, combining archaeozoological and contemporary samples, we show that Asiatic cheetahs (Acinonyx jubatus venaticus) are unambiguously separated from African subspecies. Divergence time estimates from mitochondrial and nuclear data place the split between Asiatic and Southern African cheetahs (Acinonyx jubatus jubatus) at 32 000–67 000 ya using an average mammalian microsatellite mutation rate and at 4700–44 000 ya employing human microsatellite mutation rates. Cheetahs are vulnerable to extinction globally and critically endangered in their Asiatic range, where the last 70–110 individuals survive only in Iran. We demonstrate that these extant Iranian cheetahs are an autochthonous monophyletic population and the last representatives of the Asiatic subspecies A. j. venaticus. We advocate that conservation strategies should consider the uncovered independent evolutionary histories of Asiatic and African cheetahs, as well as among some African subspecies. This would facilitate the dual conservation priorities of maintaining locally adapted ecotypes and genetic diversity. 相似文献
996.
Narendra A Reid SF Greiner B Peters RA Hemmi JM Ribi WA Zeil J 《Proceedings. Biological sciences / The Royal Society》2011,278(1709):1141-1149
Animals are active at different times of the day and their activity schedules are shaped by competition, time-limited food resources and predators. Different temporal niches provide different light conditions, which affect the quality of visual information available to animals, in particular for navigation. We analysed caste-specific differences in compound eyes and ocelli in four congeneric sympatric species of Myrmecia ants, with emphasis on within-species adaptive flexibility and daily activity rhythms. Each caste has its own lifestyle: workers are exclusively pedestrian; alate females lead a brief life on the wing before becoming pedestrian; alate males lead a life exclusively on the wing. While workers of the four species range from diurnal, diurnal-crepuscular, crepuscular-nocturnal to nocturnal, the activity times of conspecific alates do not match in all cases. Even within a single species, we found eye area, facet numbers, facet sizes, rhabdom diameters and ocelli size to be tuned to the distinct temporal niche each caste occupies. We discuss these visual adaptations in relation to ambient light levels, visual tasks and mode of locomotion. 相似文献
997.
Susanna Peters Jafargholi Imani Vera Mahler Kay Foetisch Susanne Kaul Kathrin E. Paulus Stephan Scheurer Stefan Vieths Karl-Heinz Kogel 《Transgenic research》2011,20(3):547-556
Pathogenesis-related protein-10 (PR10) is a ubiquitous small plant protein induced by microbial pathogens and abiotic stress
that adversely contributes to the allergenic potency of many fruits and vegetables, including carrot. In this plant, two highly
similar genes encoding PR10 isoforms have been isolated and designated as allergen Dau c 1.01 and Dau c 1.02. The aim of the
study was to generate PR10-reduced hypoallergenic carrots by silencing either one of these genes in transgenic carrots by
means of RNA interference (RNAi). The efficiency of gene silencing by stably expressed hairpin RNA (hnRNA) was documented
by means of quantitative RT-PCR (qPCR) and immunoblotting. Quantification of the residual protein revealed that PR10 accumulation
was strongly decreased compared with untransformed controls. Treatment of carrot plants with the PR protein-inducing chemical
salicylic acid resulted in an increase of PR10 isoforms only in wild-type but not in Dau c 1-silenced mutants. The decrease
of the allergenic potential in Dau c 1-silenced plants was sufficient to cause a reduced allergenic reactivity in patients
with carrot allergy, as determined with skin prick tests (SPT). However, simultaneous silencing of multiple allergens will
be required to design hypoallergenic carrots for the market. Our findings demonstrate the feasibility of creating low-allergenic
food by using RNAi. This constitutes a reasonable approach to allergen avoidance. 相似文献
998.
Cushing TD Baichwal V Berry K Billedeau R Bordunov V Broka C Browner MF Cardozo M Cheng P Clark D Dalrymple S DeGraffenreid M Gill A Hao X Hawley RC He X Labadie SS Labelle M Lehel C Lu PP McIntosh J Miao S Parast C Shin Y Sjogren EB Smith ML Talamas FX Tonn G Walker KM Walker NP Wesche H Whitehead C Wright M Jaen JC 《Bioorganic & medicinal chemistry letters》2011,21(1):423-426
A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKβ. In this Letter we document our efforts at further optimization of this series, culminating in 2 with submicromolar potency in a HWB assay and efficacy in a CIA mouse model. 相似文献
999.
Millan DS Ballard SA Chunn S Dybowski JA Fulton CK Glossop PA Guillabert E Hewson CA Jones RM Lamb DJ Napier CM Payne-Cook TA Renery ER Selby MD Tutt MF Yeadon M 《Bioorganic & medicinal chemistry letters》2011,21(19):5826-5830
In this Letter we present data for a novel series of ICS for the treatment of asthma. 'Inhalation by design' principles have been applied to a series of highly potent steroidal GR agonists, with a focus on optimising the potential therapeutic index in human. Pharmacokinetic properties were tuned with high intrinsic clearance and low oral bioavailability in mind, to minimise systemic exposure and reduce systemically driven adverse events. High CYP mediated clearance as well as glucuronidation were targeted to achieve high intrinsic clearance coupled with multiple routes of clearance to minimise drug-drug interactions. Furthermore, pharmaceutical properties such as stability, crystallinity and solubility were considered to ensure compatibility with a dry powder inhaler. This work culminated in the identification of the clinical candidate 15, which demonstrates preclinically the desired efficacy and safety profiles confirming its potential as an inhaled agent for the treatment of asthma. 相似文献
1000.
Wang T Ioannidis S Almeida L Block MH Davies AM Lamb ML Scott DA Su M Zhang HJ Alimzhanov M Bebernitz G Bell K Zinda M 《Bioorganic & medicinal chemistry letters》2011,21(10):2958-2961
Synthesis and biological evaluation of a series of 6-aminopyrazolyl-pyridine-3-carbonitriles as JAK2 kinase inhibitors was reported. Biochemical screening, followed by profile optimization, resulted in JAK2 inhibitors exhibiting good kinase selectivity, pharmacokinetic properties, physical properties and pharmacodynamic effects. 相似文献