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11.
EVOLUTION OF THE TELLINACEA (BIVALVIA) 总被引:1,自引:0,他引:1
The suspension feeding Astartacea appear to be among the earliestheterodonts. These organisms may have given rise to the Carditaceaand the rest of the heterodonts including the Tellinacea. Paleontological evidence indicates that the earliest Tellinaceawere suspension feeders with members that lived vertically ina burrow in shifting sand. These conditions resemble those foundin species of modern Donax in the Donacidae. From a Donax-likestate of suspension feeding evolution most likely proceededto non-selective feeders. Extant organisms that resemble thisstage are found in the Solecurtidae. A later stage resemblessome of the extant Psammobiidae. The final stage in tellinaceanevolution is the acquisition of deposit feeding with its associatedmorphology. These stages are observed in the Scrobiculariidae,Tellinidae and a few members of the Semelidae. (Received 27 April 1981; 相似文献
12.
THE DEVELOPMENT OF ENDOMYCORRHIZAL ROOT SYSTEMS 总被引:6,自引:6,他引:0
13.
Correlated binary regression using a quadratic exponential model 总被引:5,自引:0,他引:5
14.
M. A. ROSS 《Austral ecology》1976,1(4):259-263
The temperature responses of the perennial grass Eragrostis eriopoda Benth., an all-season annual grass (Enneapogon polyphyllus Domin.) and a cool-season annual forb (Lepidium muelleri-ferdinandi Thell.) were studied in two experiments, one during germination and the other during the establishment phase. In the first experiment, extreme differences in the response of germination to temperature occurred between species. The optimum was 42°C for Eragrostis and 15 to 21° C for Enneapogon and Lepidium although Enneapogon tolerated higher temperatures than did Lepidium. The effect of temperature on speed of germination is discussed. In the second experiment, seedlings were assigned to six day/night temperature regimes ranging from 24/16 C to 45/31 C for three weeks in a phytotron. Both grasses responded positively to temperatures tip to 30/22°C with little further change up to 45/37° C, while Lepidium died at temperatures greater than 30/22° C. The experimentally determined response to temperature reflected field observations of seasonal establishment patterns for each species. The ecological significance of the results is discussed. 相似文献
15.
RITA COLÓN-URBAN PAUL J. CHEUNG GEORGE D. RUGGIERI ROSS F. NIGRELLI 《Invertebrate reproduction & development.》2013,57(4):245-252
Thirty-two pedunculate barnacles, O. a. geryonophila, were maintained in culture for a period of 2 yr in the laboratory. These barnacles were obtained from the pleopods and mouth parts of the giant marine isopod, Bathynomus giganteus, which had been collected, at a depth of 200 fathoms, in the Gulf of Mexico. The carina, scutum, mandible and maxilla of adult barnacles were typical of deep water species. However, the tergum and labrum were intermediate between those of shallow and deep water species. Adults 3.1–4.1 mm in length were cultured in sea water (15–19°C), and fed on benthic copepods such as Tisbe furcata and Laophonte sp. Three broods of nauplii from 8 barnacles were obtained in 2 yr. Larvae were reared on plankton collected from Coney Island waters in which nauplii reached Stage IV in 10–14 days at 16°C. Isochrysis galbana and Thalassiosira pseudonana individually or in combination maintained nauplii to Stage IV, but with very high mortality. The lack of spines on the carapace edge of the nauplii distinguishes this deep water species from the shallow water form, O. mulleri. 相似文献
16.
ROSS A. MARKLEIN MATTHEW W. KLINKER KATHERINE A. DRAKE HANNAH G. POLIKOWSKY ELIZABETH C. LESSEY-MORILLON STEVEN R. BAUER 《Cytotherapy》2019,21(1):17-31
Background
Although a preponderance of pre-clinical data demonstrates the immunosuppressive potential of mesenchymal stromal cells (MSCs), significant heterogeneity and lack of critical quality attributes (CQAs) based on immunosuppressive capacity likely have contributed to inconsistent clinical outcomes. This heterogeneity exists not only between MSC lots derived from different donors, tissues and manufacturing conditions, but also within a given MSC lot in the form of functional subpopulations. We therefore explored the potential of functionally relevant morphological profiling (FRMP) to identify morphological subpopulations predictive of the immunosuppressive capacity of MSCs derived from multiple donors, manufacturers and passages.Methods
We profiled the single-cell morphological response of MSCs from different donors and passages to the functionally relevant inflammatory cytokine interferon (IFN)-γ. We used the machine learning approach visual stochastic neighbor embedding (viSNE) to identify distinct morphological subpopulations that could predict suppression of activated CD4+ and CD8+ T cells in a multiplexed quantitative assay.Results
Multiple IFN-γ–stimulated subpopulations significantly correlated with the ability of MSCs to inhibit CD4+ and CD8+ T-cell activation and served as effective CQAs to predict the immunosuppressive capacity of additional manufactured MSC lots. We further characterized the emergence of morphological heterogeneity following IFN-γ stimulation, which provides a strategy for identifying functional subpopulations for future single-cell characterization and enrichment techniques.Discussion
This work provides a generalizable analytical platform for assessing functional heterogeneity based on single-cell morphological responses that could be used to identify novel CQAs and inform cell manufacturing decisions. 相似文献17.
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20.
GALON I. HALL MARK C. WALLACE WARREN B. BALLARD DONALD C. RUTHVEN III MATTHEW J. BUTLER RACHAEL L. HOUCHIN ROSS T. HUFFMAN RICHARD S. PHILLIPS ROGER APPLEGATE 《The Journal of wildlife management》2007,71(8):2583-2591
ABSTRACT We recorded telemetry locations from 1,129 radiotagged turkeys (Meleagris gallopavo intermedia) on 4 study areas in the Texas Panhandle and southwestern Kansas, USA, from 2000 to 2004. Analyses of telemetry locations indicated both sexes selected riparian vegetative zones. Females did not select grazed or nongrazed pastures for daily movements. However, females did select nongrazed pastures for nest sites on 2 study areas and males selected for grazed pastures at one study area during the breeding season. We compared nest sites (n = 351) to random sites using logistic regression, which indicated height of visual obstruction, percent canopy cover, and percent bare ground provided the highest predictive power (P ≤ 0.003) for characteristics describing nest-site selection. Nest-site vegetative characteristics between vegetative zones differed primarily in composition: upland zone nest sites had more (P ≤ 0.001) shrubs and riparian zone nest sites had more (P ≤ 0.001) grass. There were no differences in measured nest site vegetative characteristics between pasture types, but there were differences between available nesting cover in grazed and nongrazed pastures. Random plots in grazed pastures had less grass cover (P ≤ 0.001) and more bare ground (P = 0.002). Because of cattle impacts on average grass height and availability, grazing would likely have the highest impact on nesting in riparian zones due to turkey use of grass as nesting cover. An appropriate grazing plan to promote Rio Grande turkey nesting habitat would include grazing upland zones in the spring, when it likely has little impact on nesting-site selection, and grazing riparian zones following breeding season completion. Grazing at light to moderate intensities with periods of rest did not affect male turkey pasture use and may have continued to maintain open areas used by male turkeys for displaying purposes. 相似文献