Rhizobium spp. show chemotaxis to plant root exudates. Both legumes and non-legume root exudates attract the different rhizobia studied. However, the bacteria show a differential response in that they are attracted to the root exudates of some plants and show no attraction toward others. An example of negative chemotaxis was also observed. The trefoil strain of Rhizobium shows chemotaxis which ...

Osmotic water flow through membranes with uniform defined pores was measured for a variety of macromolecular solutes. Water flow increased linearly with applied hydrostatic pressure, allowing the effective osmotic pressure of the solutes to be estimated by extrapolation. Reflection coefficients for each solute-membrane combination were calculated and correlated with the ratio of solute size to ...

An Inverse Decibel Log Frequency Method for Determination of the Transfer Functions of Psychobiological Systems: George L. Kreezer 681 Some New Finds of Fossil Ganoids in the Virginia Triassic: Francis M. Baer and William H. Martin .... 684 Colehicine Poisoning in Relation to Hemerocallis and Some Other Plants: Hamilton P.Traub ..................................................... 686 Preparati...

The recent literature contains numerous references to the use of partially hydrolyzed dextrans as plasma substitutes (Bull et al., 1949; Thorsen, 1949). Because of this interest, and as part of a general study of bacterial polysaccharide synthesis, the nutritional requirements of the major dextran forming organisms, Leuconostoc mesenteroides and L. dextranicum, are being investigated (Whiteside...

Dextran is a branched polysaccharide composed of about 200,000 glucose units. The glucose units in the main chain are bound together by 1:6 glucosidic linkages. A special strain of lactobacilli (lenconostoc Mesenteroides) converts sucrose to a highly linear dextran molecule which has a molecular weight of approximately 40 million. By means of partial acid hydrolysis and subsequent differential ...

Physiologically, a hallmark of biological hydrogels is their ability to selectively trap diffusing molecules and particles. And indeed, there now increasing interest in using selective hydrogel barriers for applications biomedicine medical engineering. However, when employing synthetic polymers create with permeabilities, controlling the type strength ensuing filtration process difficult. Here,...