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141.
Brooks DR Bohan DA Champion GT Haughton AJ Hawes C Heard MS Clark SJ Dewar AM Firbank LG Perry JN Rothery P Scott RJ Woiwod IP Birchall C Skellern MP Walker JH Baker P Bell D Browne EL Dewar AJ Fairfax CM Garner BH Haylock LA Horne SL Hulmes SE Mason NS Norton LR Nuttall P Randle Z Rossall MJ Sands RJ Singer EJ Walker MJ 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2003,358(1439):1847-1862
The effects of herbicide management of genetically modified herbicide-tolerant (GMHT) beet, maize and spring oilseed rape on the abundance and diversity of soil-surface-active invertebrates were assessed. Most effects did not differ between years, environmental zones or initial seedbanks or between sugar and fodder beet. This suggests that the results may be treated as generally applicable to agricultural situations throughout the UK for these crops. The direction of the effects was evenly balanced between increases and decreases in counts in the GMHT compared with the conventional treatment. Most effects involving a greater capture in the GMHT treatments occurred in maize, whereas most effects involving a smaller capture were in beet and spring oilseed rape. Differences between GMHT and conventional crop herbicide management had a significant effect on the capture of most surface-active invertebrate species and higher taxa tested in at least one crop, and these differences reflected the phenology and ecology of the invertebrates. Counts of carabids that feed on weed seeds were smaller in GMHT beet and spring oilseed rape but larger in GMHT maize. In contrast, collembolan detritivore counts were significantly larger under GMHT crop management. 相似文献
142.
143.
Females of the sea urchin Strongylocentrotus purpuratus differ in the structures of their egg jelly sulfated fucans 总被引:1,自引:0,他引:1
The egg jelly coats of sea urchins contain sulfated fucans which bind to a
sperm surface receptor glycoprotein to initiate the signal transduction
events resulting in the sperm acrosome reaction. The acrosome reaction is
an ion channel regulated exocytosis which is an obligatory event for sperm
binding to, and fusion with, the egg. Approximately 90% of individual
females of the sea urchin Strongylocentrotus purpuratus spawned eggs having
only one of two possible sulfated fucan electrophoretic isotypes, a slow
migrating (sulfated fucan I), or a fast migrating (sulfated fucan II)
isotype. The remaining 10% of females spawned eggs having both sulfated
fucan isotypes. The two sulfated fucan isotypes were purified from egg
jelly coats and their structures determined by NMR spectroscopy and
methylation analysis. Both sulfated fucans are linear polysaccharides
composed of 1-->3-linked alpha-L-fucopyranosyl units. Sulfated fucan I
is entirely sulfated at the O -2 position but with a heterogeneous
sulfation pattern at O -4 position. Sulfated fucan II is composed of a
regular repeating sequence of 3 residues, as follows: [3-alpha-L-Fuc p -
2,4(OSO3)-1-->3-alpha-L-Fuc p -4(OSO3)-1-->3-alpha-L-Fuc p -4(OSO3)-
1]n. Both purified sulfated fucans have approximately equal potency in
inducing the sperm acrosome reaction. The significance of two structurally
different sulfated fucans in the egg jelly coat of this species could
relate to the finding that the sperm receptor protein which binds sulfated
fucan contains two carbohydrate recognition modules of the C-type lectin
variety which differ by 50% in their primary structure.
相似文献
144.
Sequence variations in small-subunit ribosomal RNAs of Hartmannella vermiformis and their phylogenetic implications 总被引:1,自引:0,他引:1
Evidence of associations between free-living amoebas and human disease has
been increasing in recent years. Knowledge about phylogenetic relationships
that may be important for the understanding of pathogenicity in the genera
involved is very limited at present. Consequently, we have begun to study
these relationships and report here on the phylogeny of Hartmannella
vermiformis, a free-living amoeba that can harbor the etiologic agent of
Legionnaires' disease. Our analysis is based on studies of small-subunit
ribosomal RNA genes (srDNA). Nucleotide sequences were determined for
nuclear srDNA from three strains of H. vermiformis isolated from the United
Kingdom, Germany, and the United States. These sequences then were compared
with a sequence previously obtained for a North American isolate by J. H.
Gunderson and M. L. Sogin. The four genes are 1,840 bp long, with an
average GC content of 49.6%. Sequence differences among the strains range
are 0.38%-0.76%. Variation occurs at 19 positions and includes 2
single-base indels plus 14 monotypic and 3 ditypic single-base
substitutions. Variation is limited to eight helix/loop structures
according to a current model for srRNA secondary structure. Parsimony,
distance, and bootstrap analyses used to examine phylogenetic relationships
between the srDNA sequences of H. vermiformis and other eukaryotes
indicated that Hartmannella sequences were most closely related to those of
Acanthamoeba and the alga Cryptomonas. All ditypic sites were consistent
with a separation between European and North American strains of
Hartmannella, but results of other tests of this relationship were
statistically inconclusive.
相似文献
145.
Matt Proett Shane B. Roberts Jon S. Horne David N. Koons Terry A. Messmer 《The Journal of wildlife management》2019,83(5):1214-1225
The rapid pace of wind-energy development has increased stakeholder concerns regarding the potential effects on wildlife. Locations targeted for wind-energy development frequently overlap prairie grouse and greater sage-grouse (Centrocercus urophasianus) habitats. Research suggests that anthropogenic developments may have negative effects on these species. There is, however, no information published regarding the effect of wind-energy development on Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus), a subspecies that has twice been petitioned for Endangered Species Act protection. To address this need, from 2014 to 2015 we studied Columbian sharp-tailed grouse nesting ecology across restored grasslands in eastern Idaho, USA, where a 215-turbine wind-energy complex had been developed. We monitored 147 nests from 135 females captured at leks 0.1–13.8 km from wind turbines. We used an information-theoretic approach to evaluate the influence of wind-energy infrastructure and habitat characteristics on nest-site selection and daily nest survival. We did not detect any influence of wind-energy infrastructure on nest-site selection or nest survival. Nest-site selection and daily nest survival were influenced by vegetation structure and composition measured at 2 spatial scales. Females selected nest sites with more restored grassland containing >30% forb cover within the nesting core-use area (i.e., 60 ha around the nest) and exhibited a functional response to the availability of that land cover type. Daily nest survival was best predicted by visual obstruction at the nest site and the amount of restored grassland containing >30% forb cover within the nesting core-use area. We recommend wildlife managers continue to implement management practices that will provide bunchgrass-dominated grasslands with >30% forb cover in restored grasslands (e.g., Conservation Reserve Program fields) within Columbian sharp-tailed grouse range. © The Wildlife Society, 2019 相似文献
146.
Sarah N. Biggs Lisa M. Walter Angela R. Jackman Lauren C. Nisbet Aidan J. Weichard Samantha L. Hollis Margot J. Davey Vicki Anderson Gillian M. Nixon Rosemary S. C. Horne 《PloS one》2015,10(9)
This study aimed to determine the long term effects of resolution of SDB in preschool children, either following treatment or spontaneous recovery, on cognition and behavior. Children diagnosed with SDB at 3-5y (N = 35) and non-snoring controls (N = 25), underwent repeat polysomnography (PSG) and cognitive and behavioral assessment 3 years following a baseline study. At follow-up, children with SDB were grouped into Resolved and Unresolved. Resolution was defined as: obstructive apnea hypopnea index (OAHI) ≤1 event/h; no snoring detected on PSG; and no parental report of habitual snoring. 57% (20/35) of children with SDB received treatment, with SDB resolving in 60% (12/20). 43% (15/35) were untreated, of whom 40% (6/15) had spontaneous resolution of SDB. Cognitive reduced between baseline and follow-up, however this was not related to persistent disease, with no difference in cognitive outcomes between Resolved, Unresolved or Control groups. Behavioral functioning remained significantly worse in children originally diagnosed with SDB compared to control children, regardless of resolution. Change in OAHI did not predict cognitive or behavioral outcomes, however a reduction in nocturnal arousals, irrespective of full resolution, was associated with improvement in attention and aggressive behavior. These results suggest that resolution of SDB in preschool children has little effect on cognitive or behavioral outcomes over the long term. The association between sleep fragmentation and behavior appears independent of SDB, however may be moderated by concomitant SDB. This challenges the assumption that treatment of SDB will ameliorate associated cognitive and behavioural deficits and supports the possibility of a SDB phenotype. 相似文献
147.
Dacres H Wang J Leitch V Horne I Anderson AR Trowell SC 《Biosensors & bioelectronics》2011,29(1):119-124
Our goal is to develop a general transduction system for G-protein coupled receptors (GPCRs). GPCRs are present in most eukaryote cells and transduce diverse extracellular signals. GPCRs comprise not only the largest class of integral membrane receptors but also the largest class of targets for therapeutic drugs. In all cases studied, binding of ligand to a GPCR leads to a sub-nanometer intramolecular rearrangement. Here, we report the creation of a novel chimaeric BRET-based biosensor by insertion of sequences encoding a bioluminescent donor and a fluorescent acceptor protein into the primary sequence of a GPCR. The BRET(2)-ODR-10 biosensor was expressed in membranes of Saccharomyces cerevisiae. Assays conducted on isolated membranes indicated an EC(50) in the femtomolar range for diacetyl. The response was ligand-specific and was abolished by a single point mutation in the receptor sequence. Novel BRET-GPCR biosensors of this type have potential application in many fields including explosive detection, quality control of food and beverage production, clinical diagnosis and drug discovery. 相似文献
148.
The expression pattern of MUC1 glycoforms and other biomarkers of endometrial receptivity in fertile and infertile women 总被引:4,自引:0,他引:4
Horne AW Lalani EN Margara RA Ryder TA Mobberley MA White JO 《Molecular reproduction and development》2005,72(2):216-229
Changes in the surface epithelium of the endometrium, characterized in part by alterations in cell-surface molecules, sex steroid receptors and the appearance of pinopodes, coincide with the window of endometrial receptivity in the menstrual cycle. This study was performed to evaluate the usefulness of hematoxylin and eosin staining, scanning and transmission microscopy, and MUC1 glycoform, sex steroid receptor, and interleukin receptor (type 1) expression as biomarkers of endometrial receptivity using carefully characterized clinical fertile and infertile groups of women. Using a combination of immunohistochemistry and scanning electron microscopy (SEM) called scanning immunoelectron microscopy (SIM), we confirmed that MUC1 mucin was not associated with the endometrial pinopodes, which have been linked with embryo adhesion. We also showed that failure of embryo implantation was associated with an abnormal endometrial expression of MUC1 mucin, and retention of nuclear progesterone receptor (PR) particularly in epithelial cells. Hematoxylin and eosin staining, transmission electron microscopy (TEM), SEM in isolation and immunohistochemistry for interleukin receptor were not shown to be useful markers. Progesterone-dependent regulation of MUC1 appears to be an important factor in determining endometrial receptivity. 相似文献
149.
Helen Dacres Mira M. Dumancic Irene Horne Stephen C. Trowell 《Analytical biochemistry》2009,385(2):194-124
Bioluminescence resonance energy transfer (BRET) is a powerful tool for the study of protein-protein interactions and conformational changes within proteins. Two common implementations of BRET are BRET1 with Renilla luciferase (RLuc) and coelenterazine h (CLZ, λem ∼ 475 nm) and BRET2 with the substrate coelenterazine 400a (CLZ400A substrate, λem = 395 nm) as the respective donors. For BRET1 the acceptor is yellow fluorescent protein (YFP) (λem ∼ 535 nm), a mutant of green fluorescent protein (GFP), and for BRET2 it is GFP2 (λem ∼ 515 nm). It is not clear from previous studies which of these systems has superior signal-to-background characteristics. Here we directly compared BRET1 and BRET2 by placing two different protease-specific cleavage sequences between the donor and acceptor domains. The intact proteins simulate protein-protein association. Proteolytic cleavage of the peptide linker simulates protein dissociation and can be detected as a change in the BRET ratios. Complete cleavage of its target sequence by thrombin changed the BRET2 ratio by a factor of 28.9 ± 0.2 (relative standard deviation [RSD], n = 3) and changed the BRET1 ratio by a factor of 3.05 ± 0.07. Complete cleavage of a caspase-3 target sequence resulted in the BRET ratio changes by factors of 15.45 ± 0.08 for BRET2 and 2.00 ± 0.04 for BRET1. The BRET2 assay for thrombin was 2.9 times more sensitive compared with the BRET1 version. Calculated detection limits (blank signal + 3σb, where σb = standard deviation [SD] of blank signal) were 53 pM (0.002 U) thrombin with BRET1 and 15 pM (0.0005 U) thrombin with BRET2. The results presented here suggest that BRET2 is a more suitable system than BRET1 for studying protein-protein interactions and as a potential sensor for monitoring protease activity. 相似文献
150.
Rigotti DJ Kokona B Horne T Acton EK Lederman CD Johnson KA Manning RS Kane SA Smith WF Fairman R 《Analytical biochemistry》2005,346(2):189-200
We describe a quantitative analysis of Acanthamoeba castellanii myosin II rod domain images collected from atomic force microscope experiments. These images reveal that the rod domain forms a novel filament structure, most likely requiring unusual head-to-tail interactions. Similar filaments are seen also in negatively stained electron microscopy images. Truncated myosins from Acanthamoeba and other model organisms have been visualized before, revealing laterally associated bipolar minifilaments. In contrast, the filament structures that we observe are dominated by axial rather than lateral polymerization. The unusually small features in this structure (1-5 nm) required the development of quantitative and statistical techniques for filament image analysis. These techniques enhance the extraction of features that hitherto have been difficult to ascertain from more qualitative imaging approaches. The heights of the filaments are observed to have a bimodal distribution consistent with the diameters of a single rod domain and a pair of close-packed rod domains. Further quantitative analysis indicates that in-plane association is limited to at most a pair of rod domains. Taken together, this implies that the filaments contain no more than four rod domains laterally associated with one another, somewhat less than that seen in bipolar minifilaments. Analysis of images of the filaments decorated with an anti-FLAG antibody reveals head-to-tail association with mean distances between the antibodies of 75 +/- 15 nm. We consider a set of molecular models to help interpret possible structures of the filaments. 相似文献