Effect of Far Red Light on Drought Resistance of Cotton

The resistance of cotton (Gossypium hirsutum L.) to droughtstress was increased when plants, grown under a 9 h light period,received a 30 min far red (FR) illumination at the beginningof the dark period. With the addition of FR light, the plantsdisplayed higher stomatal resistance and lower rate of transpiration.Therefore, with the addition of FR, the plants remained at higherleaf turgor potential during the period of drought stress whencompared to plants stressed without the FR illumination. ThusFR illumination improved the water economy of the plants. (Received April 20, 1982; Accepted August 30, 1982)     

Population structure,dispersal and colonization history of the garden bumblebee <Emphasis Type="Italic">Bombus hortorum</Emphasis> in the Western Isles of Scotland

New methods of analysing genetic data provide powerful tools for quantifying dispersal patterns and reconstructing population histories. Here we examine the population structure of the bumblebee Bombus hortorum in a model island system, the Western Isles of Scotland, using microsatellite markers. Following declines in other species, B. hortorum is the only remaining long-tongued bumblebee species found in much of Europe, and thus it is of particular ecological importance. Our data suggest that populations of B. hortorum in western Scotland exist as distinct genetic clusters occupying groups of nearby islands. Population structuring was higher than for other bumblebee species which have previously been studied in this same island group (F_st = 0.16). Populations showed significant isolation by distance. This relationship was greatly improved by using circuit theory to allow dispersal rates to differ over different landscape features; as we would predict, sea appears to provide far higher resistance to dispersal than land. Incorporating bathymetry data improved the fit of the model further; populations separated by shallow seas are more genetically similar than those separated by deeper seas. We argue that this probably reflects events following the last ice age when the islands were first colonized by this bee species (8,500–5,000 ybp), when the sea levels were lower and islands separated by shallow channels would have been joined. In the absence of significant gene flow these genetic clusters appear to have since diverged over the following 5,000 years and arguably may now represent locally adapted races, some occurring on single islands.     

Mitral regurgitation: when to intervene?

Although mitral regurgitation (MR) is the most common valvular heart disease, it should be regarded as a complex multifactorial disease that involves     

Human retinoblastomas have binding sites for the COOH-terminal segment of human beta-endorphin

Two human retinoblastoma cell lines (Y79 and McA) were evaluated for the presence of binding sites for human beta-endorphin (beta h-EP). Using tritiated beta h-EP (3H-beta h-EP) and synthetic beta-EP analogues, it was possible to demonstrate binding sites for 3H-beta h-EP with an ED50 of 3.5 nM in Y79 cells and 8 nM in McA cells respectively. The non-opioid segment [beta h-EP-(6-31)] retained about 20% relative potency in Y79 and 40% in McA in displacing the tritiated hormone when compared with beta h-EP. Camel beta-EP had a relative potency of less than 1% and beta h-EP-(1-27) was inactive in both cells in doses as high as 4 microM. Taken together with previous reports on similar binding sites in human neuroblastoma and glioblastoma cell lines, it appears that cell lines of neural origin have binding sites for the COOH-terminal of human beta-EP.     

In vivo phosphorylation of proteins in Clostridium sphenoides

Abstract Cell contents of Clostridium sphenoides , labeled with [³²P]orthophosphate under strict anaerobic conditions, were analyzed by two-dimensional gel electrophoresis. Autoradiography of these gels demonstrated the presence of at least 15 ³²P-labeled protein species, of which M _r and iso-electric point were determined. Treatment of the radioactively labeled cell contents with alkaline phosphatase and acid phosphatase showed that all these proteins were modified by phosphorylation. These findings demonstrate for the first time the presence of phosphorproteins in a strictly anaerobic bacterium.