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911.
912.
S.A. Kim Y.M. Lee I.G. Hwang D.H. Kang G.J. Woo M.S. Rhee 《Letters in applied microbiology》2009,49(5):620-626
Aims: The efficiency of eight enrichment broths for the selective isolation of Campylobacter jejuni was compared to identify an optimal enrichment broth.
Methods and Results: Brucella-FBP, Preston, Doyle and Roman, modified CCD (mCCD), Park and Sanders, Bolton, Hunt and Radle and Hunt broths were compared for their recovery of (i) Camp. jejuni in suspension, (ii) Camp. jejuni from inoculated ground pork, (iii) heat-injured Camp. jejuni (55°C for 20 min) in suspension and (iv) heat-injured Camp. jejuni from inoculated ground pork. Hunt broth and Bolton broth showed the highest and most rapid enrichment efficacy for the cell suspensions and ground pork, respectively. Preston, Park and Sanders and mCCD broths had relatively high enrichment efficiencies, while Brucella-FBP broth was significantly inferior to the other broths ( P < 0·05).
Conclusions: Cell recovery from the eight enrichment broths was dependent on the sample type and the state of the cells. The use of the appropriate broth is important for the rapid and efficacious enrichment of Camp. jejuni . In particular, heat-injured Camp. jejuni require a longer cultivation time and a suitable enrichment broth.
Significance and Impact of the Study: The results from the present study provide information for selecting the most appropriate enrichment broth for Camp. jejuni and may contribute to improved detection methods for the organism. 相似文献
Methods and Results: Brucella-FBP, Preston, Doyle and Roman, modified CCD (mCCD), Park and Sanders, Bolton, Hunt and Radle and Hunt broths were compared for their recovery of (i) Camp. jejuni in suspension, (ii) Camp. jejuni from inoculated ground pork, (iii) heat-injured Camp. jejuni (55°C for 20 min) in suspension and (iv) heat-injured Camp. jejuni from inoculated ground pork. Hunt broth and Bolton broth showed the highest and most rapid enrichment efficacy for the cell suspensions and ground pork, respectively. Preston, Park and Sanders and mCCD broths had relatively high enrichment efficiencies, while Brucella-FBP broth was significantly inferior to the other broths ( P < 0·05).
Conclusions: Cell recovery from the eight enrichment broths was dependent on the sample type and the state of the cells. The use of the appropriate broth is important for the rapid and efficacious enrichment of Camp. jejuni . In particular, heat-injured Camp. jejuni require a longer cultivation time and a suitable enrichment broth.
Significance and Impact of the Study: The results from the present study provide information for selecting the most appropriate enrichment broth for Camp. jejuni and may contribute to improved detection methods for the organism. 相似文献
913.
914.
Christopher L. Coe Gabriele R. Lubach Kay M. Izard 《American journal of primatology》1994,32(1):51-55
Antibody levels were determined in adults and newborn offspring of five primate species. This cross-species comparison of intant IgG levels indicated that prosimians and New World monkeys transfer lower levels of maternal antibody via placental transmission than do Old World monkeys, apes, and humans. The evolutionary trend toward an increased reliance on prenatal antibody transfer in the higher primates appears to be most pronounced in the human infant, because our placenta has evolved an active transport process that elevates IgG in the full-term fetus over maternal levels. Higher IgG levels in the young infant ensure a more prolonged and successful period of passive immunity against pathogens previously encountered by the mother. © 1994 Wiley-Liss, Inc. 相似文献
915.
Adrienne Zihlman 《American journal of primatology》1984,6(4):381-382
This report describes periodic oscillations in electroencephalographic (EEG) and behavioral activity with a cycle length of 15–30 seconds in chair-restrained squirrel monkeys (Saimiri sciureus). These oscillations consisted of alternating episodes of vigilance, characterized by visual scanning and motor movement, and inattentiveness, characterized by behavioral quiescence with little eye or limb movement. During vigilance the EEG exhibited low-amplitude, high-frequency (> 16 Hz) activity. During quiescent periods, a high-amplitude synchronized EEG was present with activity in the 8–16-Hz band predominating. The presence or frequency of this EEG and behavioral periodicity was not modified by time of day, as no difference was found between morning and afternoon recording sessions. Although the factors or mechanisms responsible for this rhythm are unclear, it should be noted by those investigators studying the behavior or neurophysiology of Saimiri sciureus in the laboratory setting. 相似文献
916.
ABSTRACT Birds often fly close to the ground or water. Wind shear theory predicts that wind speeds decline with proximity to the substratum, so birds might be expected to fly lower when flying upwind than when flying downwind. We tested this prediction and found that the wind shear equation is valid at heights below 4 m, with wind speed over a smooth surface ~40% lower at a height of 0.08 m than at 4 m. Birds that fly close enough to smooth substrata can also benefit energetically from ground effect, where vortices generated by their flight interact with the ground or water. This suggests that birds should use ground effect more when flying upwind than when flying downwind. We determined the percent time spent flying in ground effect by 21 species of passerine and non‐passerine birds flying in sheltered coastal aquatic and nearby terrestrial areas of County Cork, Ireland. We found that use of ground effect was uncommon for passerines, but common for a variety of non‐passerine waterbirds. However, phylogenetic analysis indicates no linkage between phylogeny and incidence of ground effect use and it is probable that incidence of use is determined by ecology rather than phylogeny. Great Cormorants (Phalacrocorax carbo) used ground effect most frequently over water (59.4% of time in flight). Over land, Barn Swallows (Hirundo rustica) used ground effect most often (19.8% of time). Phylogenetic contrasts regression analysis showed no significant relationship between use of ground effect and either wing aspect ratio or wing loading for 18 of our focal species, though simple linear regression analysis indicated that birds with greater wing loading used ground effect slightly (but significantly) more often. We found that 95% of Great Cormorants flying upwind used ground effect whereas only 35% did so when flying downwind. Few Black‐headed Gulls (Chroicocephalus ridibundus) used ground effect (probably because they fly high to locate prey), but still showed greater use when flying upwind (25%) than downwind (2.5%). When flying upwind in ground effect at the wind speeds encountered in our study, the velocity for minimum power (Vmp) for Great Cormorants was exceeded, suggesting theoretical benefits of about 14.3%. Our study indicates that several species exploit both wind shear and ground effect to minimize energy expenditure during commuting and foraging, but that others do not, because of either complexity of habitat morphology or the demands of their foraging ecology. 相似文献
917.
KHRISTI A. WILKINS RICHARD A. MALECKI PATRICK J. SULLIVAN JOSEPH C. FULLER JOHN P. DUNN LARRY J. HINDMAN GARY R. COSTANZO SCOTT A. PETRIE DENNIS LUSZCZ 《The Journal of wildlife management》2010,74(5):1107-1111
ABSTRACT Our objective was to determine whether there were subpopulations within the eastern population of tundra swans (Cygnus columbianus columbianus) wintering along the mid-Atlantic coast. Movement rates between regions were substantial enough to result in continual mixing of wintering birds. Thus, we were unable to identify distinct subpopulations based on exclusive use of specific wintering areas. These birds should therefore be monitored, and their harvest managed, as if they were one population. 相似文献
918.
AbstractIn 1822, William Buckland first recognized Pleistocene vertebrate coprolites, and they are now known from more multiple localities with a global distribution. Carnivore coprolites dominate, and there are two distinct biogeographic and taphonomic provinces for vertebrate coprolites in the Pleistocene. The Castrocopros province of North and South America is characterized by a dominance of herbivore coprolites, which are preserved almost exclusively in caves. The Hyaenacoprus province in Africa, Europe and Asia is dominated by hyena coprolites that occur mainly in caves, but also in other depositional environments. Pacific Islands may represent a third province characterized by dominant bird coprolites from caves, but the known localities are all Holocene. Mammuthocopros allenorum ichnogen. and ichnosp. nov. is a coprolite of Mammuthus columbi from Utah, USA. 相似文献
919.
Ria L. Mitchell Paul Kenrick Silvia Pressel Jeff Duckett Christine Strullu-Derrien Neil Davies William J. McMahon Rebecca Summerfield 《Geobiology》2023,21(4):454-473
The evolution of the first plant-based terrestrial ecosystems in the early Palaeozoic had a profound effect on the development of soils, the architecture of sedimentary systems, and shifts in global biogeochemical cycles. In part, this was due to the evolution of complex below-ground (root-like) anchorage systems in plants, which expanded and promoted plant–mineral interactions, weathering, and resulting surface sediment stabilisation. However, little is understood about how these micro-scale processes occurred, because of a lack of in situ plant fossils in sedimentary rocks/palaeosols that exhibit these interactions. Some modern plants (e.g., liverworts, mosses, lycophytes) share key features with the earliest land plants; these include uni- or multicellular rhizoid-like anchorage systems or simple roots, and the ability to develop below-ground networks through prostrate axes, and intimate associations with fungi, making them suitable analogues. Here, we investigated cryptogamic ground covers in Iceland and New Zealand to better understand these interactions, and how they initiate the sediment stabilisation process. We employed multi-dimensional and multi-scale imaging, including scanning electron microscopy (SEM) and X-ray Computed Tomography (μCT) of non-vascular liverworts (Haplomitriopsida and complex thalloids) and mosses, with additional imaging of vascular lycopods. We find that plants interact with their substrate in multiple ways, including: (1) through the development of extensive surface coverings as mats; (2) entrapment of sediment grains within and between networks of rhizoids; (3) grain entwining and adherence by rhizoids, through mucilage secretions, biofilm-like envelopment of thalli on surface grains; and (4) through grain entrapment within upright ‘leafy’ structures. Significantly, μCT imaging allows us to ascertain that rhizoids are the main method for entrapment and stabilisation of soil grains in the thalloid liverworts. This information provides us with details of how the earliest land plants may have significantly influenced early Palaeozoic sedimentary system architectures, promoted in situ weathering and proto-soil development, and how these interactions diversified over time with the evolution of new plant organ systems. Further, this study highlights the importance of cryptogamic organisms in the early stages of sediment stabilisation and soil formation today. 相似文献
920.
Claud A. Bramblett 《American journal of primatology》1992,26(1):73-74
Videolaparoscopy was used to visualize the reproductive tract contractility of the squirrel monkey, Saimiri sciureus. This technique gives information on the nature, direction of propagation, duration, and frequency of contractions. At the times of ovulation, and embryo entry to the uterus, contractile activity was observed in both the uterus and oviduct, with the latter being more frequent. The dominant direction of propagation was towards the utero-tubal junction, and simultaneous contractions were frequently observed in both uterus and oviduct. © 1992 Wiley-Liss, Inc. 相似文献