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51.
Taxonomy and systematics in biodiversity research 总被引:1,自引:1,他引:0
A new species of freshwater kamptozoan (Entoprocta) is described from the Mae Klong and Prachin Buri Rivers in central Thailand. This brings to two the number of known entoproct species occurring in fresh water. The new species, Loxosomatoides sirindhornae, grows as stolonate colonies; each diminutive zooid has a muscular, unsegmented stalk, and an obliquely oriented calyx. A well-formed hibernaculum originates from a short, lateral stolon at the base of certain zooids. The calyx bears a rigid shield with a conspicuous aboral carina extending along the entire length. Colonies have been found only in fully freshwater habitats and appear not to tolerate salinities higher than 1.0 ppt. 相似文献
52.
Segers P Carlier S Pasquet A Rabben SI Hellevik LR Remme E De Backer T De Sutter J Thomas JD Verdonck P 《American journal of physiology. Heart and circulatory physiology》2000,279(2):H542-H549
We fitted a three-segment transmission line model for the radial-carotid/aorta pressure transfer function (TFF) in 31 controls and 30 patients with coronary artery disease using noninvasively measured (tonometry) radial and carotid artery pressures (P(car)). Except for the distal reflection coefficient (0.85 +/- 0.21 in patients vs. 0.71 +/- 0.25 in controls; P < 0.05), model parameters were not different between patients or controls. Parameters were not related to blood pressure, age, or heart rate. We further assessed a point-to-point averaged TFF (TFF(avg)) as well as upper (TFF(max)) and lower (TFF(min)) enveloping TFF. Pulse pressure (PP) and augmentation index (AIx) were derived on original and reconstructed P(car) (P(car,r)). TFF(avg) yielded closest morphological agreement between P(car) and P(car,r) (root mean square = 4.3 +/- 2.3 mmHg), and TTF(avg) best predicted PP (41.5 +/- 11.8 vs. 41.1 +/- 10.0 mmHg measured) and AIx (-0.02 +/- 0.19 vs. 0.01 +/- 0.19). PP and AIx, calculated from P(car) or P(car,r), were higher in patients than in controls, irrespectively of the TFF used. We conclude that 1) averaged TFF yield significant discrepancies between reconstructed and measured pressure waveforms and subsequent derived AIx; and 2) different TFFs seem to preserve the information in the pressure wave that discriminates between controls and patients. 相似文献
53.
Segers P Georgakopoulos D Afanasyeva M Champion HC Judge DP Millar HD Verdonck P Kass DA Stergiopulos N Westerhof N 《American journal of physiology. Heart and circulatory physiology》2005,288(3):H1157-H1164
Global assessment of both cardiac and arterial function is important for a meaningful interpretation of pathophysiological changes in animal models of cardiovascular disease. We simultaneously acquired left ventricular (LV) and aortic pressure and LV volume (V(LV)) in 17 open-chest anesthetized mice (26.7 +/- 3.2g) during steady-state (BL) and caval vein occlusion (VCO) using a 1.4-Fr dual-pressure conductance catheter and in a subgroup of eight animals during aortic occlusion (AOO). Aortic flow was obtained from numerical differentiation of V(LV). AOO increased input impedance (Z(in)) for the first two harmonics, increased characteristic impedance (0.025 +/- 0.007 to 0.040 +/- 0.011 mmHg x microl(-1) x s, P < 0.05), and shifted the minimum in Z(in) from the third to the sixth harmonic. For all conditions, the Z(in) could be well represented by a four-element windkessel model. The augmentation index increased from 116.7 +/- 7.8% to 145.9 +/- 19.5% (P < 0.01) as well as estimated pulse-wave velocity (3.50 +/- 0.94 to 5.95 +/- 1.62 m/s, P < 0.05) and arterial elastance (E(a), 4.46 +/- 1.62 to 6.02 +/- 1.43 mmHg/microl, P < 0.01). AOO altered the maximal slope (E(max), 3.23 +/- 1.02 to 5.53 +/- 1.53 mmHg/microl, P < 0.05) and intercept (-19.9 +/- 8.6 to 1.62 +/- 13.51 microl, P < 0.01) of the end-systolic pressure-volume relation but not E(a)/E(max) (1.44 +/- 0.43 to 1.21 +/- 0.37, not significant). We conclude that simultaneous acquisition of Z(in) and arterial function parameters in the mouse, based solely on conductance catheter measurements, is feasible. We obtained an anticipated response of Z(in) and arterial function parameters following VCO and AOO, demonstrating the sensitivity of the measuring technique to induced physiological alterations in murine hemodynamics. 相似文献
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Following previous reports indicating a remarkable high diversity of sessile rotifers in Southeast Asian freshwaters, we report on an extensive study of the diversity of Collothecidae rotifers from fifteen freshwater habitats in Thailand. A total of 13 species, including two additional infraspecific variants, of Collothecidae are recorded, one of which is described as a new species of Collotheca. We further add taxonomic remarks on some of the taxa on record and illustrate the uncinate trophi of several representatives by scanning electron microscopic images. Finally, we provide illustrated identification keys to the Collothecidae recorded to date from Southeast Asia. 相似文献
57.
Migratory patterns of bats are not well understood and traditional methods to study this, like capture-mark-recapture, may not provide enough detail unless there are many records. Stable isotope profiles of many animal species have been used to make inferences about migration. Each year Myotis lucifugus and M. septentrionalis migrate from summering roosts to swarming caves and mines in the fall, but the pattern of movement between them is not well understood. In this study, fur δ13C and δ15N values of 305 M. lucifugus and 200 M. septentrionalis were analyzed to make inferences about migration patterns between summering areas and swarming sites in Nova Scotia, Canada. We expected that there would be greater variability in δ13C and δ15N among individuals at swarming sites because it was believed that these sites are used by individuals originating from many summering areas. There was extensive overlap in the standard ellipse area, corrected for small sample sizes (SEAc), of bats at swarming sites and much less overlap in SEAc among groups sampled at summering areas. Meaningful inference could not be made on M. septentrionalis because their low variation in SEAc may have been the result of sampling only 3 summering areas. However, for M. lucifugus, swarming sites had larger SEAc than summering areas and predictive discriminant analysis assigned swarming bats to multiple summering areas, supporting the contention that swarming bats are mixed aggregations of bats from several summering areas. Together, these data support the contention that swarming sites have catchment areas for bats from multiple summering areas and it is likely that the catchment areas for swarming sites overlap. These data suggest that δ13C and δ15N profiling of bat fur offer some potential to make inferences about regional migration in bats. 相似文献
58.
Separate effects of moisture content and water activity on the hyphal extension of Penicillium rubens on porous media 下载免费PDF全文
Karel A. van Laarhoven Hendrik P. Huinink Frank J. J. Segers Jan Dijksterhuis Olaf C. G. Adan 《Environmental microbiology》2015,17(12):5089-5099
To prevent indoor fungal growth, understanding the moisture relations of fungi is a key element. Indoor moisture is quantified by the relative humidity (RH). RH controls the water activity of the indoor materials that fungi grow on, a well‐studied parameter known to limit fungal growth. RH, however, also controls the amount of water present in these materials, the moisture content. The significance of the moisture content of these materials to indoor fungal growth is currently overlooked. In the work reported here, growth experiments with the indoor fungus Penicillium rubens on gypsum substrates were performed to test whether the moisture content influences growth on porous materials. Second, we report the development of a video microscopy method that for the first time quantified hyphal growth on a porous material. It is found that a higher moisture content leads to earlier colonization and higher hyphal extension rates. This is a fundamental step in unravelling the effect of RH on indoor fungal growth. The real‐time monitoring of colonization of gypsum provides a new view of growth on indoor surfaces. 相似文献
59.
Development of a high-throughput screening assay for the discovery of small-molecule SecA inhibitors
A major pathway for bacterial preprotein translocation is provided by the Sec-dependent preprotein translocation pathway. Proteins destined for Sec-dependent translocation are synthesized as preproteins with an N-terminal signal peptide, which targets them to the SecYEG translocase channel. The driving force for the translocation reaction is provided by the peripheral membrane ATPase SecA, which couples the hydrolysis of ATP to the stepwise transport of unfolded preproteins across the bacterial membrane. Since SecA is essential, highly conserved among bacterial species, and has no close human homologues, it represents a promising target for antibacterial chemotherapy. However, high-throughput screening (HTS) campaigns to identify SecA inhibitors are hampered by the low intrinsic ATPase activity of SecA and the requirement of hydrophobic membranes for measuring the membrane or translocation ATPase activity of SecA. To address this issue, we have developed a colorimetric high-throughput screening assay in a 384-well format, employing an Escherichia coli (E. coli) SecA mutant with elevated intrinsic ATPase activity. The assay was applied for screening of a chemical library consisting of ∼27,000 compounds and proved to be highly reliable (average Z′ factor of 0.89). In conclusion, a robust HTS assay has been established that will facilitate the search for novel SecA inhibitors. 相似文献
60.
Fen Wu Yu Chen Faruque Parvez Stephanie Segers Maria Argos Tariqul Islam Alauddin Ahmed Muhammad Rakibuz-Zaman Rabiul Hasan Golam Sarwar Habibul Ahsan 《PloS one》2013,8(3)