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41.
Parente TE Rebelo MF da-Silva ML Woodin BR Goldstone JV Bisch PM Paumgartten FJ Stegeman JJ 《Gene》2011,489(2):111-118
The Amazon catfish genus Pterygoplichthys (Loricariidae, Siluriformes) is closely related to the loricariid genus Hypostomus, in which at least two species lack detectable ethoxyresorufin-O-deethylase (EROD) activity, typically catalyzed by cytochrome P450 1 (CYP1) enzymes. Pterygoplichthys sp. liver microsomes also lacked EROD, as well as activity with other substituted resorufins, but aryl hydrocarbon receptor agonists induced hepatic CYP1A mRNA and protein suggesting structural/functional differences in Pterygoplichthys CYP1s from those in other vertebrates. Comparing the sequences of CYP1As of Pterygoplichthys sp. and of two phylogenetically related siluriform species that do catalyze EROD (Ancistrus sp., Loricariidae and Corydoras sp., Callichthyidae) showed that these three proteins share amino acids at 17 positions that are not shared by any fish in a set of 24 other species. Pterygoplichthys and Ancistrus (the loricariids) have an additional 22 amino acid substitutions in common that are not shared by Corydoras or by other fish species. Pterygoplichthys has six exclusive amino acid substitutions. Molecular docking and dynamics simulations indicate that Pterygoplichthys CYP1A has a weak affinity for ER, which binds infrequently in a productive orientation, and in a less stable conformation than in CYP1As of species that catalyze EROD. ER also binds with the carbonyl moiety proximal to the heme iron. Pterygoplichthys CYP1A has amino acid substitutions that reduce the frequency of correctly oriented ER in the AS preventing the detection of EROD activity. The results indicate that loricariid CYP1As may have a peculiar substrate selectivity that differs from CYP1As of most vertebrate. 相似文献
42.
Sarah Ann Woodin Rachel Ann Merz 《Evolution; international journal of organic evolution》1987,41(2):427-432
We examined the hooked setae of a dominant group of tube-dwellers, the polychaete annelids, and found a pattern of setation that is predictable by tube type, exclusive of worm taxon or orientation; we also demonstrated the mechanical significance of these hooked setae. When tube-dwelling worms belonging to different lineages are pressurized, they resist differentially as a function of the direction in which hooks face. The results are consistent with the hypothesis that hooks are used primarily to resist removal of worms from their tubes, are polyphyletic in origin, and are active agents of resistance. 相似文献
43.
KC Kosinski MN Adjei KM Bosompem JJ Crocker JL Durant D Osabutey JD Plummer MJ Stadecker AD Wagner M Woodin DM Gute 《PLoS neglected tropical diseases》2012,6(7):e1709
Background
Urogenital schistosomiasis caused by Schistosoma haematobium was endemic in Adasawase, Ghana in 2007. Transmission was reported to be primarily through recreational water contact.Methods
We designed a water recreation area (WRA) to prevent transmission to school-aged children. The WRA features a concrete pool supplied by a borehole well and a gravity-driven rainwater collection system; it is 30 m2 and is split into shallow and deep sections to accommodate a variety of age groups. The WRA opened in 2009 and children were encouraged to use it for recreation as opposed to the local river. We screened children annually for S. haematobium eggs in their urine in 2008, 2009, and 2010 and established differences in infection rates before (2008–09) and after (2009–10) installation of the WRA. After each annual screening, children were treated with praziquantel and rescreened to confirm parasite clearance.Principal Findings
Initial baseline testing in 2008 established that 105 of 247 (42.5%) children were egg-positive. In 2009, with drug treatment alone, the pre-WRA annual cumulative incidence of infection was 29 of 216 (13.4%). In 2010, this incidence rate fell significantly (p<0.001, chi-squared) to 9 of 245 (3.7%) children after installation of the WRA. Logistic regression analysis was used to determine correlates of infection among the variables age, sex, distance between home and river, minutes observed at the river, low height-for-age, low weight-for-age, low Body Mass Index (BMI)-for-age, and previous infection status.Conclusion/Significance
The installation and use of a WRA is a feasible and highly effective means to reduce the incidence of schistosomiasis in school-aged children in a rural Ghanaian community. In conjunction with drug treatment and education, such an intervention can represent a significant step towards the control of schistosomiasis. The WRA should be tested in other water-rich endemic areas to determine whether infection prevalence can be substantially reduced. 相似文献44.
Arctic ecosystems are important habitats for Arctic breeding geese which in their turn have a profound impact on the vegetation
in these areas. The herbivore pressure is currently on the rise in the region and may interact with climate change to drive
changes in both productivity and decomposition rates. In this study, we aim to determine the combined impact of warming and
geese on C pools and decomposition in two high Arctic habitats, mesic heath and wet meadow. We employed field-experimental
warming and grazing treatments in a fully factorial design and quantified their impact on ecosystems C pools and turnover.
High grazing levels reduced vascular biomass and litter C pools at both sites, whereas warming reduced moss biomass at the
mesic site only. Grazing increased decomposition rates and reduced the amount of labile C in the soil at the mesic site, whereas
warming substantially reduced C concentrations by approximately 25%. Intermediate level of grazing had an opposite effect
and resulted in increased soil C storage at the mesic site. In contrast, no effects of the treatment on belowground C cycling
were found at the wet site. In conclusion, the two levels of grazing and warming impacted on different aspects of the C cycle
investigated in this study. The high grazing and warming treatment promoted reduced carbon storage/decomposition both above-
and belowground with the strongest effects seen at the mesic site. 相似文献
45.
46.
Lisa D. McCartain Michael Townsend Simon F. Thrush David S. Wethey Sarah A. Woodin Nils Volkenborn 《Marine and Freshwater Behaviour and Physiology》2017,50(4):239-255
A laboratory experiment was conducted, to examine how feeding, siphon activity and movement behaviours of a tellinid bivalve, Macomona liliana (Iredale, 1915), were affected by thin surface layers of mud (1–4 mm) and the incorporation of mud into surface (0–2 cm) sediment. Time-lapse photography and porewater pressure sensors were used to characterise changes in behaviour before and after mud addition. Mud addition modified the sediment matrix which had an immediate effect on M. liliana behaviour; significantly affecting the rates of feeding and the degree of porewater pressurisation during feeding events. Surface activity indicated maintenance and clearance of established burrow structures and increased ventilation. Ultimately, subtle modifications in behaviour and sediment hydraulic conductivity may have consequences for nutrient exchange and benthic-pelagic coupling. Our results emphasise the need to consider the impacts of low level stressors when they affect the behaviour of structurally important species. 相似文献
47.
Northern permafrost soils contain important carbon stocks. Here we report the long-term response of carbon stocks in high Arctic dwarf shrub tundra to short-term, low-level nutrient enrichment. Twenty years after experimental nitrogen addition, carbon stocks in vegetation and organic soil had almost halved. In contrast, where phosphorus was added with nitrogen, carbon storage increased by more than 50%. These responses were explained by changes in the depths of the moss and organic soil layers. Nitrogen apparently stimulated decomposition, reducing carbon stocks, whilst phosphorus and nitrogen co-stimulated moss productivity, increasing organic matter accumulation. The altered structure of moss and soil layers changed soil thermal regimes, which may further influence decomposition of soil carbon. If climate warming increases phosphorus availability, any increases in nitrogen enrichment from soil warming or expanding human activity in the Arctic may result in increased carbon sequestration. Where phosphorus is limiting in tundra areas, however, nitrogen enrichment may result in carbon loss. 相似文献
48.
We report changes in biomarker enzymes (cytochrome P4501A, glutathione-S-transferase) and protein expression (cytochrome P4501A) in adult painted turtles, Chrysemys picta, as part of a study of the potential impact of contaminants originating from the Massachusetts Military Reservation on Cape, Cod, MA. In animals from both Moody Pond, a site potentially impacted by contaminants, and Washburn Pond, a nonimpacted site, rates of hepatic microsomal ethoxyresorufin-O 相似文献
49.
Quantitative analysis of sugar constituents of glycoproteins by capillary electrophoresis 总被引:4,自引:0,他引:4
A method for quantitative analysis of monosaccharides including N-
acetylneuraminic acid derived from sialic acid-containing oligosaccharides
and glycoproteins is presented. The analysis is based on the combination of
chemical and enzymatic methods coupled with capillary electrophoretic (CE)
separation and laser-induced fluorescence (LIF) detection. The present
method utilizes a simplified acid hydrolysis procedure consisting of mild
hydrolysis (0.1 M TFA) to release sialic acid and strong acid hydrolysis
(2.0 N TFA) to produce amino and neutral sugars. Amino sugars released from
strong acid hydrolysis of oligosaccharides and glycoproteins were
reacetylated and derivatized with 8-aminopyrene-1,3,6-trisulfonate (APTS)
along with neutral sugars in the presence of sodium cyanoborohydride to
yield quantitatively the highly stable fluorescent APTS adducts. N-
acetylneuraminic acid (Neu5Ac), a major component of most mammalian
glycoproteins, was converted in a fast specific reaction by the action of
neuraminic acid aldolase (N-acylneuraminate pyruvate-lyase EC 4.1.3.3) to
N-acetylmannosamine (ManNAc) and pyruvate. ManNAc was then derivatized with
APTS in the same manner as the other monosaccharides. This method was
demonstrated for the quantitation of pure Neu5Ac and the species derived
from mild acid hydrolysis of 6'-sialyl-N- acetyllactosamine and bovine
fetuin glycan. Quantitative recovery of the N-acetylmannosamine was
obtained from a known amount of Neu5Ac in a mixture of seven other
monosaccharides or from the sialylated oligosaccharides occurring in
glycoproteins. The sequence of procedures consists of acid hydrolysis,
enzymatic conversion and APTS derivatization which produced quantitative
recovery of APTS- monosaccharide adducts. The detection limits for sugars
derivatized with APTS and detected by CE-LIF are 100 pmol for Neu5Ac and 50
pmol for the other sugars.
相似文献
50.