Insects and fungi on a C3 sedge and a C4 grass exposed to elevated atmospheric CO2 concentrations in open-top chambers in the field

The effects of elevated atmospheric CO₂ concentration on plant-fungi and plant-insect interactions were studied in an emergent marsh in the Chesapeake Bay. Stands of the C₃ sedge Scirpus olneyi Grey, and the C₄ grass Spartina patens (Ait.) Muhl. have been exposed to elevated atmospheric CO₂ concentrations during each growing season since 1987. In August 1991 the severities of fungal infections and insect infestations were quantified. Shoot nitrogen concentration ([N]) and water content (WC) were determined. In elevated concentrations of atmospheric CO₂, 32% fewer S. olneyi plants were infested by insects, and there was a 37% reduction in the severity of a pathogenic fungal infection, compared with plants grown in ambient CO₂ concentrations. S. olneyi also had reduced [N], which correlated positively with the severities of fungal infections and insect infestations. Conversely, S. patens had increased WC but unchanged [N] in elevated concentrations of atmospheric CO₂ and the severity of fungal infection increased. Elevated atmospheric CO₂ concentration increased or decreased the severity of fungal infection depending on at least two interacting factors, [N] and WC; but it did not change the number of plants that were infected with fungi. In contrast, the major results for insects were that the number of plants infected with insects decreased, and that the amount of tissue that each insect ate also decreased.     

A comparative study of four dredges used for sampling benthic macroinvertebrates in rivers

SUMMARY. After considering the large number of dredges described in the literature, four light-weight dredges were chosen for manual operation from a small boat or the bank: Irish triangular dredge, small Fast dredge, medium-sized and large Naturalist's dredges. The dredges were tested in a series of trials at three sites in two rivers. A stratified random sample (number of sampling units, n = 5) was taken at each site and the modal particle sizes at sites 1–3 were 1–2 mm (fine gravel), 64–128 mm (larger stones) and 128–256 mm, respectively. The dredges usually took a similar range of stone sizes at each site but the design of the Fast dredge excluded larger stones (>16 mm). The Irish dredge sometimes failed to operate correctly. Variations in the volume of substrata taken with each dredge were large, both between sampling units in the same sample and between samples. The latter differences were partially due to the increase in the modal size of the stones, especially between sites 1 and 2, the different sampling areas of the dredges and the depth of penetration into the substratum. Penetration depth was probably greatest for the two Naturalist's dredges, smaller for the Fast dredge and smallest for the Irish dredge. In field trials, the relative abundances of major taxa were similar for most dredges at each site; major exceptions were the Fast dredge at site 2 and the Irish dredge at site 3. There was a high variability between sampling units in the same sample and therefore a lack of precision in the estimates of the mean number of invertebrates per sample. Therefore, the dredges cannot be used as quantitative samplers for the estimation of population density. Their adequacy as qualitative samplers for the estimation of total number of taxa per sample varied considerably and maximum estimates of their efficiencies for a small sample (n= 5) were <40% for the Irish and Fast dredges, >57% for the medium-sized Naturalist's dredge and >76% for the large Naturalist's dredge. There was a clear relationship between the number of taxa and the number of invertebrates taken at each site and this relationship was well described by a power law with an exponent within the range 0.18–0.53. The number of sampling units in the sample had no significant effect on the power-law equations for each site. The power-law equation was very similar for most of the dredges at each site, the only major exception being the Fast dredge at site 1. The implications of this relationship are discussed.     

Morphological profiling using machine learning reveals emergent subpopulations of interferon-γ–stimulated mesenchymal stromal cells that predict immunosuppression

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.