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241.
We sampled populations of forest-floor dwelling cave and ground wētā using footprint tracking tunnels and spotlight transect counts in southern beech forest, New Zealand. Samples were compared to estimates of wētā density based on mark–recapture estimates from 25?m2 enclosures. Both activity indices captured variability in cave wētā in time and space, were strongly correlated with each other, and have the potential for monitoring cave wētā activity levels. Comparisons between indices and cave wētā density estimates were equivocal, as recapture rates were too low to calculate high-resolution density estimates. We also found that cave wētā counts had a curved relationship increasing with temperature, and a negative relationship with increasing shrub and woody debris cover. Based on these preliminary results, tracking tunnels could be a viable method of monitoring cave wētā as they appear more efficient than transect counts and are relatively inexpensive. However, further calibration trials are needed to determine if indices mirror robust population density estimates. 相似文献
242.
243.
Worldwide patterns of mitochondrial DNA differentiation in the harbor seal (Phoca vitulina) 总被引:3,自引:0,他引:3
Stanley HF; Casey S; Carnahan JM; Goodman S; Harwood J; Wayne RK 《Molecular biology and evolution》1996,13(2):368-382
The harbor seal (Phoca vitulina) has one of the broadest geographic
distributions of any pinniped, stretching from the east Baltic, west across
the Atlantic and Pacific Oceans to southern Japan. Although individuals may
travel several hundred kilometers on annual feeding migrations, harbor
seals are generally believed to be philopatric, returning to the same areas
each year to breed. Consequently, seals from different areas are likely to
be genetically differentiated, with levels of genetic divergence increasing
with distance. Differentiation may also be caused by long-standing
topographic barriers such as the polar sea ice. We analyzed samples of 227
harbor seals from 24 localities and defined 34 genotypes based on 435 bp of
control region sequence. Phylogenetic analysis and analysis of molecular
variance showed that populations in the Atlantic and Pacific Oceans and
east and west coast populations of these oceans are significantly
differentiated. Within these four regions, populations that are
geographically farthest apart generally are the most differentiated and
often do not share genotypes or differ in genotype frequency. The average
corrected sequence divergence between populations in the Atlantic and
Pacific Oceans is 3.28% +/- 0.38% and those among populations within each
of these oceans are 0.75% +/- 0.69% and 1.19% +/- 0.65%, respectively. Our
results suggest that harbor seals are regionally philopatric, on the scale
of several hundred kilometers. However, genetic discontinuities may exist,
even between neighboring populations such as those on the Scottish and east
English coasts or the east and west Baltic. The mitochondrial data are
consistent with an ancient isolation of populations in both oceans, due to
the development of polar sea ice. In the Atlantic and Pacific, populations
appear to have been colonized from west to east with the European
populations showing the most recent common ancestry. We suggest the recent
ancestry of European seal populations may reflect recolonization from Ice
Age refugia after the last glaciation.
相似文献
244.
Maged1, a new regulator of skeletal myogenic differentiation and muscle regeneration 总被引:1,自引:0,他引:1
Tuan HN Nguyen Mathieu JM Bertrand Christiane Sterpin Younes Achouri Olivier RY De Backer 《BMC cell biology》2010,11(1):57
Background
In normal adult skeletal muscle, cell turnover is very slow. However, after an acute lesion or in chronic pathological conditions, such as primary myopathies, muscle stem cells, called satellite cells, are induced to proliferate, then withdraw definitively from the cell cycle and fuse to reconstitute functional myofibers. 相似文献245.
Zirconyl hematoxylin stains acidic mucins darkly and specifically using a solution of 100 mg hematoxylin, 5 ml ethanol, 5 ml 0.5% sodium iodate, 400 mg zirconyl chloride octahydrate, and 30 ml 25% aqueous glycerol. The stain is especially advantageous for studying goblet cells and Paget cells. 相似文献
246.
Estavillo JM Merino P Pinto M Yamulki S Gebauer G Sapek A Corré W 《Plant and Soil》2002,239(2):253-265
Soils are an important source of N2O, which can be produced both in the nitrification and the denitrification processes. Grassland soils in particular have a high potential for mineralization and subsequent nitrification and denitrification. When ploughing long term grassland soils, the resulting high supply of mineral N may provide a high potential for N2O losses. In this work, the short-term effect of ploughing a permanent grassland soil on gaseous N production was studied at different soil depths. Fertiliser and irrigation were applied in order to observe the effect of ploughing under a range of conditions. The relative proportions of N2O produced from nitrification and denitrification and the proportion of N2 gas produced from denitrification were determined using the methyl fluoride and acetylene specific inhibitors. Irrespectively to ploughing, fertiliser application increased the rates of N2O production, N2O production from nitrification, N2O production from denitrification and total denitrification (N2O + N2). Application of fertiliser also increased the denitrification N2O/N2 ratio both in the denitrification potential and in the gaseous N productions by denitrification. Ploughing promoted soil organic N mineralization which led to an increase in the rates of N2O production, N2O production from nitrification, N2O production from denitrification and total denitrification (N2O + N2). In both the ploughed and unploughed treatments the 0–10 cm soil layer was the major contributing layer to gaseous N production by all the above processes. However, the contribution of this layer decreased by ploughing, gaseous N productions from the 10 to 30 cm layer being significantly increased with respect to the unploughed treatment. Ploughing promoted both nitrification and denitrification derived N2O production, although a higher proportion of N2O lost by denitrification was observed as WFPS increased. Recently ploughed plots showed lower denitrification derived N2O percentages than those ploughed before as a result of the lower soil water content in the former plots. Similarly, a lower mean nitrification derived N2O percentage was found in the 10–30 cm layer compared with the 0–10 cm. 相似文献
247.
Alexandre C Motta Joost LM Vissers Renée Gras Betty CAM Van Esch Antoon JM Van Oosterhout Martijn C Nawijn 《Respiratory research》2009,10(1):1-8
Background
Anxiety and depression are common and treatable risk factors for re-hospitalisation and death in patients with COPD. The degree of lung function impairment does not sufficiently explain anxiety and depression. The BODE index allows a functional classification of COPD beyond FEV1. The aim of this cross-sectional study was (1) to test whether the BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms; and (2) to assess which components of the BODE index are associated with these psychological aspects of COPD.Methods
COPD was classified according to the GOLD stages based on FEV1%predicted in 122 stable patients with COPD. An additional four stage classification was constructed based on the quartiles of the BODE index. The hospital anxiety and depression scale was used to assess anxious and depressive symptoms.Results
The overall prevalence of anxious and depressive symptoms was 49% and 52%, respectively. The prevalence of anxious symptoms increased with increasing BODE stages but not with increasing GOLD stages. The prevalence of depressive symptoms increased with both increasing GOLD and BODE stages. The BODE index was superior to FEV1%predicted for explaining anxious and depressive symptoms. Anxious symptoms were explained by dyspnoea. Depressive symptoms were explained by both dyspnoea and reduced exercise capacity.Conclusion
The BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms in COPD patients. These psychological consequences of the disease may play a role in future classification systems of COPD. 相似文献248.
Hoorelbeke B Van Damme EJ Rougé P Schols D Van Laethem K Fouquaert E Balzarini J 《Retrovirology》2011,8(1):10-16
Background
In a recent report, the carbohydrate-binding specificities of the plant lectins Galanthus nivalis (GNA) and the closely related lectin from Zea mays (GNAmaize) were determined by glycan array analysis and indicated that GNAmaize recognizes complex-type N-glycans whereas GNA has specificity towards high-mannose-type glycans. Both lectins are tetrameric proteins sharing 64% sequence similarity.Results
GNAmaize appeared to be ~20- to 100-fold less inhibitory than GNA against HIV infection, syncytia formation between persistently HIV-1-infected HuT-78 cells and uninfected CD4+ T-lymphocyte SupT1 cells, HIV-1 capture by DC-SIGN and subsequent transmission of DC-SIGN-captured virions to uninfected CD4+ T-lymphocyte cells. In contrast to GNA, which preferentially selects for virus strains with deleted high-mannose-type glycans on gp120, prolonged exposure of HIV-1 to dose-escalating concentrations of GNAmaize selected for mutant virus strains in which one complex-type glycan of gp120 was deleted. Surface Plasmon Resonance (SPR) analysis revealed that GNA and GNAmaize interact with HIV IIIB gp120 with affinity constants (KD) of 0.33 nM and 34 nM, respectively. Whereas immobilized GNA specifically binds mannose oligomers, GNAmaize selectively binds complex-type GlcNAcβ1,2Man oligomers. Also, epitope mapping experiments revealed that GNA and the mannose-specific mAb 2G12 can independently bind from GNAmaize to gp120, whereas GNAmaize cannot efficiently bind to gp120 that contained prebound PHA-E (GlcNAcβ1,2man specific) or SNA (NeuAcα2,6X specific).Conclusion
The markedly reduced anti-HIV activity of GNAmaize compared to GNA can be explained by the profound shift in glycan recognition and the disappearance of carbohydrate-binding sites in GNAmaize that have high affinity for mannose oligomers. These findings underscore the need for mannose oligomer recognition of therapeutics to be endowed with anti-HIV activity and that mannose, but not complex-type glycan binding of chemotherapeutics to gp120, may result in a pronounced neutralizing activity against the virus. 相似文献249.
Díaz López E A Morales Ruíz EJ Vargas Ramírez P Hernández Herrera RC Reséndiz Melgar I Brena Hernández JM Loeza Corte 《Phyton》2015,84(2):319-330
The effect of six phosphorus levels (0, 40, 80, 120, 160 and 200 kg/ha) on the duration of cumulative leaf area, biomass and agronomic yield was determined in the maize cultivars: Amarillo Almoloya, Cacahuacintle and Condor in 2010 and 2011. Such cultivars were sown in the Cerrillo Piedras Blancas Mexico. A completely randomized complete block design with factorial arrangement was utilized. High phosphorus levels (120, 160 and 200 kg/ha) positively affected the duration of cumulative leaf area; greatest values were obtained in Cacahuacintle. A greater duration of accumulated leaf area contributes to determine high values of biomass accumulation and grain yield in this cultivar. Leaf area duration appeared to be a useful tool for evaluating different genotypes in a given environment. 相似文献
250.