Manganese and iron encrustations and other features ofPlanctomyces crassus Hortobágyi 1965, morphotype Ib of theBlastocaulis-Planctomyces group of budding and appendaged bacteria,examined by electron microscopy and X-ray micro-analysis

Water samples collected in August, 1980, from a pond in Budapest, Hungary, have permitted transmission and scanning electron microscopic observations to be made ofPlanctomyces crassus Hortobágyi 1965, which—to remain taxonomically noncommittal—we designated as morphotype Ib of theBlastocaulis-Planctomyces group of appendaged and budding bacteria. The detailed cell morphology of morphotype Ib (cellular shape, size and distribution pattern of crateriform structures, pili, spires) was similar to that of morphotype Ia,Planctomyces bekefii Gimesi 1924. The major appendage—a seemingly tubular, multifibrillar stalk—differed somewhat from the stalk of morphotype Ia, in that the morphotype Ib stalk was generally shorter than the morphotype Ia stalk, was tapered (the morphotype Ia stalk was uniformly cylindrical), and apparently lacked the organizing matrix of the morphotype Ia stalk. Energy-dispersive X-ray spectroscopy of the metallic-oxide encrustations of morphotype Ib rosettes revealed manganese and iron to be the predominant elements present. Moreover, localized differences were found in the relative amounts of the two elements deposited in different rosettes and at different loci on the same rosette.     

A 78-megadalton plasmid occurs in avirulent strains as well as virulent strains ofCorynebacterium fascians

Ten wild-type strains ofCorynebacterium fascians, which differed in degree of virulence as measured by ability to cause hyperplasias (multiple stems; fasciation) in pea seedlings, were examined for the presence of plasmids. Four strains were highly virulent, three were avirulent, and three were intermediate in virulence. All of these wild-type strains harbored one plasmid each of approximately 78 megadaltons, as estimated from electrophoretic mobilities in agarose gels capable of resolving reference plasmids ranging from 8.8 to 350 Mdal. Restriction endonuclease (EcoRI andBamHI) cleavage patterns of these nominally 78-MdalC. fascians plasmids suggest that the plasmids are not uniformly of high homology, although similar or identical in electrophoretic mobility in the system used. The relationship of the 78-Mdal plasmids to the phytopathogenicity ofC. fascians remains uncertain, although the restriction endonuclease cleavage patterns do indicate that the plasmids from the highly virulent strains are more closely related to the plasmids from the strains intermediate in virulence than they are to the plasmids from the avirulent strains.     

On the processing of saliva samples for progesterone assay

Reports from several laboratories indicate that the concentration of progesterone in the saliva provides a valid indicator of corpus luteum function. However; optimal conditions for the treatment and storage of saliva specimens prior to analysis was not addressed in these papers. We have found that 1) sonication of saliva in brief bursts produces a homogeneous sample from which progesterone is removed quantitatively by a single extraction with hexane in a vortex mixer, and 2) prompt freezing of saliva is important since storage of samples at room temperature for 48 hours results in a significant decrease in radioimmunoassayable progesterone. Four normal women provided daily saliva specimens throughout one menstrual cycle and serum samples every 3 days during the luteal phase. Excellent correlations between the progesterone profiles in the two fluids were obtained.     

The blue pigment of Corynebacterium insidiosum

Summary The alfalfa wilt bacterium, Corynebacterium insidiosum, produces a water-insoluble blue substance which accumulates extracellularly. A number of factors (among them strain variation, temperature, p_H, nutrition, crowding) have a considerable influence upon pigment production. Proper control of these factors led to a method for large-scale cultivation of C. insidiosum under conditions of good pigmentation.On the bases of absorption spectrum, solubility characteristics, and the properties of crystalline acetyl and benzoyl derivatives, the C. insidiosum pigment is believed to be identical with indigoidine—a pigment of unknown composition previously reported in Pseudomonas indigofera.     

Australia''s oldest human remains: age of the Lake Mungo 3 skeleton

We have carried out a comprehensive ESR and U-series dating study on the Lake Mungo 3 (LM3) human skeleton. The isotopic Th/U and Pa/U ratios indicate that some minor uranium mobilization may have occurred in the past. Taking such effects into account, the best age estimate for the human skeleton is obtained through the combination of U-series and ESR analyses yielding 62,000+/-6000 years. This age is in close agreement with OSL age estimates on the sediment into which the skeleton was buried of 61,000+/-2000 years. Furthermore, we obtained a U-series age of 81,000+/-21,000 years for the calcitic matrix that was precipitated on the bones after burial. All age results are considerably older than the previously assumed age of LM3 and demonstrate the necessity for directly dating hominid remains. We conclude that the Lake Mungo 3 burial documents the earliest known human presence on the Australian continent. The age implies that people who were skeletally within the range of the present Australian indigenous population colonized the continent during or before oxygen isotope stage 4 (57,000-71,000 years).     

Microelectrode study of K+ accumulation by tight epithelia: I. Baseline values of split frog skin and toad urinary bladder

Toad bladder and split frog skin were impaled with fine-tipped single- and double-barrelled K+-selective microelectrodes. In order to circumvent membrane damage induced by impaling toad bladder, a null point method was developed, involving elevations of mucosal potassium concentration. The results suggest that intracellular potassium activity of short-circuited toad bladder is approximately 82 mM, twice as large as earlier estimates. Far more stable and rigorously defined intracellular measurements were recorded from short-circuited split frog skins. The intracellular positions of the micropipette and microelectrode tips were verified by transient hyperpolarizations of the membrane potential with mucosal amiloride or by transient depolarizations with serosal barium or strophanthidin. Simultaneous impalement of distant cells with separate micropipettes demonstrated that both the baseline membrane potentials and the responses to depolarizing agents were similar, further documenting that frog skin is a functional syncytium. Measurements with double-barrelled microelectrodes and simultaneous single-barrelled microelectrodes and reference micropipettes suggest that the intracellular potassium activity is about 104 mM, lower than previously reported. Taken together with measurements of intracellular potassium concentration, this datum suggests that potassium is uniformly distributed within the epithelial cells.