Studies on the phylogenetic distribution of pyruvate oxidoreductases

Lactate dehydrogenase is present in all phyla examined. Alanopine and strombine dehydrogenase activities are present in all major phyla except the Arthropoda, Echinodermata and Chordata. Octopine dehydrogenase is also absent from the latter phyla and virtually absent from the Annelida. The opine dehydrogenase activities are generally absent from non-marine species. Relationships can be observed between malate dehydrogenase and glutamic-oxaloacetic transaminase and between the latter and glutamic-pyruvic transaminase in certain phyla. The results support the suggestion that the opine pathways are used in tissues to generate high (relatively) rates of energy production.     

Kinetics of amyloplast sedimentation in gravistimulated maize coleoptiles

Inner mesophyll cells from coleoptiles of Zea mays L. cv. Merit were fixed after varying periods of gravistimulation. A statistically significant amount (17–21%) of amyloplast sedimentation occurred in these cells after 30 s of gravistimulation. The presentation time is approx. 40 s or less. The accumulation of amyloplasts near the new lower wall shows a linear relationship to the logarithm of the gravistimulation time (r=0.92 or higher). The intercept of this line with the baseline value of amyloplasts in vertical coleoptiles indicates that the number of amyloplasts on the new lower wall begins increasing 11–15 s after the onset of gravistimulation. Direct observations of living cells confirm that many amyloplasts sediment within less than 15–30 s. These rapid kinetics are consistent with the classical statolith hypothesis of graviperception involving the sedimentation of amyloplasts to the vicinity of the new lower wall.     

Ueber die Transpiration der Kartoffel

Ohne Zusammenfassung     

Die perivaskulären Strukturen der menschlichen Neurohypophyse

Zusammenfassung Die Blutgefäße der menschlichen Neurohypophyse weisen besonders komplizierte perivaskuläre Strukturen auf, die aus 5 Schichten aufgebaut sind. Diese Schichten bestehen aus: 1. den Nervengeflechten, 2. den Perizyten, 3. der perivaskulären Glia, 4. den Pituizyten und 5. dem Bindegewebe. Die Rolle der Astroglia wird in der Neurohypophyse von den Pituizyten übernommen. Es wird angenommen, daß der komplizierte Aufbau der perivaskulären Strukturen der Neurohypophyse der morphologische Ausdruck für die besonderen Funktionen dieses Organs im Rahmen der Neurosekretion ist.Mit Unterstützung des U.S. Department of Public Health, Education and Welfare, Grant No. B-1251.