Brevibacterium divaricatum: Influence of nutritional conditions on the wall composition and release of uncross-linked peptidoglycan chains into medium

Purified cell walls, originating from penicillin-treated (3 g/ml, 1 h) and-untreated Brevibacterium divaricatum cells grown on complex (CM) and glucose minimal medium with (MM) or without (Ca-free MM) calcium carbonate, were isolated by two procedures. Electron micrographs and chemical analysis revealed no differences between identically isolated walls with respect to the presence or absence of either penicillin or calcium carbonate in the glucose growth medium. On the contrary, the appearance and peptidoglycan content of the walls was greatly dependent on the procedure used for their isolation and the walls isolated from the cells grown on complex medium contained more materials other than peptidoglycan. It was shown that the presence of calcium carbonate in the glucose minimal medium was essential for accumulation of large amounts of peptidoglycan chains into the medium. Penicillin-induced interruption of cell wall synthesis was prerequisite for manifestation of the calcium carbonate stimulating effect.Abbreviations CM complex medium - MM chemically defined minimal medium based on glucose and containing calcium carbonate - Ca-free MM MM modified only by the omission of calcium carbonate - ET-walls Enzyme treated walls - FPR-walls French press-ruptured walls     

Relationship of transient electrical properties to active sodium transport by toad urinary bladder

Summary Application of voltage pulses of 10 mV for periods of 9 sec across toad urinary bladder elicits a rapid deflection in transepithelial current. Frequently, the current decays back towards its baseline value during the course of the polarizing pulse. This transient phenomenon can be induced, or its magnitude increased, by raising the mucosal or serosal Na⁺ concentration. The transient can be abolished by sufficiently hyperpolarizing the tissue (rendering serosa positive to mucosa), by inhibiting transcellular Na⁺ transport with amiloride or ouabain, and by increasing the serosal K⁺ concentration. Vasopressin increases net Na⁺ movement across toad bladder but does not elicit these transients. It is proposed as a working hypothesis for further study that the transient behavior characterized in this study reflects: (1) the partition of Na⁺ between the apical plasma membrane and contiguous fluid layers, (2) the partition of K⁺ between the basolateral plasma membrane and adjacent submucosal fluid layer, and (3) the negative feedback interaction between intracellular Na⁺ activity and Na⁺ permeability of the apical plasma membrane of the transporting cells.     

Constrained sessile drop as a new configuration to measure low surface tension in lung surfactant systems.

Existing methodology for surface tension measurements based on drop shapes suffers from the shortcoming that it is not capable to function at very low surface tension if the liquid dispersion is opaque, such as therapeutic lung surfactants at clinically relevant concentrations. The novel configuration proposed here removes the two big restrictions, i.e., the film leakage problem that is encountered with such methods as the pulsating bubble surfactometer as well as the pendant drop arrangement, and the problem of the opaqueness of the liquid, as in the original captive bubble arrangement. A sharp knife edge is the key design feature in the constrained sessile drop that avoids film leakage at low surface tension. The use of the constrained sessile drop configuration in conjunction with axisymmetric drop shape analysis to measure surface tension allows complete automation of the setup. Dynamic studies with lung surfactant can be performed readily by changing the volume of a sessile drop, and thus the surface area, by means of a motor-driven syringe. To illustrate the validity of using this configuration, experiments were performed using an exogenous lung surfactant preparation, bovine lipid extract surfactant (BLES) at 5.0 mg/ml. A comparison of results obtained for BLES at low concentration between the constrained sessile drop and captive bubble arrangement shows excellent agreement between the two approaches. When the surface area of the BLES film (0.5 mg/ml) was compressed by about the same amount in both systems, the minimum surface tensions attained were identical within the 95% confidence limits.     

Beitrag zur Kenntnis desAlnetum incanae in der Tschechischen Sozialistischen Republik (ČSR)

Gegenstand dieses Beitrages ist die syntaxonomisch-synökologische Charakteristik desAlnetum incanae Lüdi 1921 in den Tschechischen Ländern. Bestände dieser montanen Auenwaldassoziation begleiten hier Flussgewässer in Gebirgstälern und am Hochgebirgsrand, meist in den Lagen von 650–900 mü. NN. DasAlnetum incanae wird in zwei Subassoziationen geteilt. Das feuchteliebendeAlnetum incanae calthetosum Knapp exNeuhäuslová-Novotná subass. nova ist an Gleyböden (Nassgleye, sauerstoffreiche Gleye) gebunden, dasAlnetum incanae typicum Oberd. 1949 (mit zwei Varianten)bestockt Paternia-Böden. DieAegopodium podagraria-Variante der typischen Subassoziation bevorzugt pedogenetisch mehr entwickelte Böden mit tiefem Grund-wasser, meist in der Kontaktzone zu Klimaxgesellschaften.     

Beitrag zur Kenntnis der Waldgesellschaften der Kleinen Karpaten,Slowakei 2. Standortsverhältnisse

In diesem Beitrag werden die Standortsverhältnisse der kleinkarpatischen Laubwaldgesellschaften (Carici pilosae-Carpinetum, sekundärerPrimula-Eichen-Hainbuchenwald,Festuco heterophyllae-Quercetum, Stellario-Alnetum, Carici remotae-Fraxinetum, Dentario bulbiferae-Fagetum, Cephalanthero-Fagetum, Phyllitidi-Aceretum, Luzulo-Fagetum, Eu-Quercion pubescentis, Luzulo albidae-Quercetum) behandelt. Besonders wurden die Beziehungen der genannten Gesellschaften zu den physikalischen und chemischen Bodeneigenschaften und Bodentypen sowie ihre Höhenverbreitung verfolgt. Ein zusammenfassender Standortsvergleich dieser Gesellschaften mit einem Bestimmungsschlüssel nach Standortsverhältnisschen ist beigefügt.     

Beitrag zur Kenntnis desPruno-Fraxinetum in der Tschechischen Sozialistischen Republik

Der Beitrag bringt Resultate syntaxonomisch-synökologischer Forschungen planarer Erlen-Eschenwälder (Pruno-Fraxinetum Oberd. 1953), die Gleyböden mit langsam bewegtem Grundwasser bestocken. Im westlichen Teil der Tschechoslowakei wurden drei Subassoziationen unterschieden: 1.Pruno-Fraxinetum filipenduletosum Mik. 1963—der feuchteste Flügel der Assoziation auf Nassgley mit hochanstehendem Grundwasser 2.Pruno-Fraxinetum typicum Oberd. 1957— die vorherrschende Ausbildung der Assoziation auf von Zeit zu Zeit oberflächlich schwach abtrocknendem Braunerde- oder typischem gley, 3.Pruno-Fraxinetum listeretosum Mik. 1963 auf karbonathaltigen Gleyböden im Kontakt mit Eichen-Hainbuchenwäldern.     

Beitrag zur kenntnis der waldgesellschaften der kleinen karpaten,slowakei I. Phytozönologische verhältnisse

In diesem Beitrag ist eine kurze Übersicht der Waldgesellschaften des Südteils der Kleinen Karpaten enthalten. Die ziemlich verschiedenen Standortsverhältnisse in diesem verhältnismässig kleinen Gebiete bedingen das Entstehen einer Reihe von Laubwaldgesellschaften mit sehr abweichenden Standortsansprüchen, wieCarici pilosae-Carpinetum, sekundärerPrimula-Eichen-Hainbuchenwald,Festuco heterophyllae-Quercetum, Stellario-Alnetum, Carici remotae-Fraxinetum, Dentario-Fagetum, Cephalanthero-Fagetum, Phyllitidi-Aceretum, Luzulo-Fagetum, Cotino-Quercetum pubescentis, Ceraso (mahaleb)-Quercetum undLuzulo-Quercetum. Den einzelnen Gesellschaften sind ihre phytozönotische Charakteristik und ein Schriftenvergleich beigefügt.