In situ fixation of cultured mouse peritoneal exudate cells: Comparison of fixation methods

Summary Mouse peritoneal exudate cells grown in vitro on plastic petri dishes were fixed in situ with both glutaraldehyde and osmium tetroxide by a variety of contemporary methods. The goal of the investigation was to determine which method resulted in the best ultrastructural preservation. The parameters being tested included: (a) the method of fixation, i.e. either sequential or simultaneous; (b) the buffer vehicle for fixation, i.e. cocodylate, Mellonig's phosphate, Sorenson's phosphate, ors-collidine; and (c) the temperature of fixation. Results presented indicate that simultaneous fixation is far superior to sequential methods. Samples fixed sequentially at 4° C consistently had better morphological preservation than samples fixed under similar conditions at 23° C. With the exception ofs-collidine, which was totally unacceptable for in vitro in situ fixation on plastic, comparable results were noted with different buffer vehicles. Previous reports by Cohn and coworkers (1–3) have established that adherent peritoneal exudate cells (PEC) are monocytoid, i.e. macrophages. Thus, in this report, the term adherent peritoneal exudate cells will be used synonymously with macrophages. Supported by a grant from the U.S. Veterans Administration entitled “A Comparative Study of Normal and Activated Macrophages.”     

Origin of the Vaccinia Virus Hemagglutinin

The relationship between the vaccinia virus hemagglutinin and hemadsorption was examined. Hemagglutinin synthesis was temporally related to the appearance of the hemadsorption reaction. Only chicken erythrocytes, which reacted with hemagglutinin, hemadsorbed to infected cells, and both of these reactions were inhibited by Ca(2+). The distribution of the vaccinia hemagglutinin and 5'-adenosine monophosphatase, a plasma membrane marker enzyme, in sucrose gradients was similar. Plasma membrane ghosts derived from infected cells hemadsorbed erythrocytes and yielded hemagglutinin upon sonic disruption. These data suggest that the majority of vaccinia hemagglutinin is derived from the plasma-membrane of the infected cell.     

Über die Durchlässigkeit dünner Sandschichten für Licht

Zusammenfassung Das Vorkommen ausgedehnter Blaualgenschichten 4–5 mm unter der Oberfläche des Kniepsandes auf Amrum veranlaßte die Messung der Lichtdurchlässigkeit dünner Sandschichten. Die Messungen erfolgten mit Hilfe eines Selen-Photoelementes im blauen, grünen und roten Licht für trockenen und durchfeuchteten Sand. Das Licht dringt in feuchten Sand tiefer ein als in trockenen. Aus den Relativwerten der Lichtdurchlässigkeit werden die Extinktionskoeffizienten des Sandes für die Spektralbereiche Blau mit 1,181 und 0,666, für Grün mit 0,852 und 0,471 und Rot mit 0,572 und 0,301 für trockenen und feuchten Sand bestimmt. Der Sand verhält sich in dickeren Schichten wie ein Rotfilter, auf dessen ökologische Bedeutung für Algen und Purpurbakterien des Farbstreifensandwattes hingewiesen wird.Mit 1 TextabbildungHerrn Prof. Dr.Tischler zum 70. Geburtstag gewidmet.     

Sterile Germination Requirements of Seeds of Some Water Plants

A sterile germination study with seeds of some common phanerogamic water plants showed almost 100 per cent germination for seeds of Alisma plantago–aquatica, Baldellia ranunculoides and Nymphaea alba. Seeds of Potamogeton lucens could be germinated to about 40 per cent, seeds of Polygonum amphibium germinated sporadically while those of Cladium mariscus could not be germinated at all. Freshly harvested seeds of Alisma and Baldellia showed an ability to germinate at both 20°C and 35°C. A stratification period of one month at +4°C gave germination of all species tested, with the exception of Cladium. Potamogeton germinated in light only, the other species both in light and darkness. Treatment times for surface sterilization in disinfectants are given.     

Measurement of Serotonin Turnover Rate in Rat Dorsal Raphe Nucleus by In Vivo Electrochemistry

5-Hydroxytryptamine (5-HT; serotonin) turnover rate in dorsal raphe nucleus of the urethane-anesthetized rat was estimated by using the in vivo electrochemical detector to measure the decay of extraneuronal 5-hydroxyindole acetic acid (5-HIAA) after monoamine oxidase inhibition. Carbon paste electrodes were scanned by semiderivative voltammetry and revealed two peaks: one at +0.15 V and the other at +0.25 V. The higher potential peak is composed primarily of the 5-HT metabolite 5-HIAA. After administration of pargyline, 75 mg/kg i.p., this peak declined exponentially. Regression analysis of these data by an exponential decay model yielded the fractional rate constant 0.82 +/- 0.06 h-1 (mean +/- SEM). This rate constant of 5-HIAA disappearance measured by in vivo electrochemistry is identical to the rate constant found by others measuring 5-HIAA disappearance by direct tissue assay methods. In animals not treated with pargyline, tissue 5-HIAA concentrations in the dorsal raphe nucleus were measured by HPLC with electrochemical detection. The average 5-HT turnover rate calculated as the product of the fractional rate constant and steady-state tissue 5-HIAA concentration was 12.6 nmol/g/h. These results demonstrate that electrochemical detection of extraneuronal 5-HIAA combined with monoamine oxidase inhibition can be used to measure neurotransmitter turnover in vivo in a discrete brain region.     

Spatial structure of chacma baboon groups

A method is presented for measuring the location of individuals with respect to the center or perimeter of a primate group. The method estimates an individual’s domain of danger: the area in which a hidden predator is closer to the individual than to other group members (cf. Hamilton, 1971). A domain is determined by the directions and distances of particular neighbors from a given individual. Animals at peripheral locations have relatively large domains, whereas animals at central locations have relatively small domains. Domains of danger were sampled for members of two groups of chacma baboons (Papio ursinus)in northern Botswana, to test for nonrandom spatial patterns throughout the day. Females with infants had significantly smaller domains than did females without infants. Domains also were correlated with social ranks of females;high-ranking females had smaller domains than did low-ranking females, possibly because high-ranking females were more likely to have infant offspring. For adult males, however,domain sizes were not significantly correlated with social ranks. Immigration status of adult males, rather than social rank, better accounted for spatial positioning.