Adelphamoeba galeacystis n. g., n. sp., an Amoeboflagellate Isolated from Soil*

SYNOPSIS. An amoeboflagellate isolated from common soil is described. The amoeboid stage is typically limax and contains a well differentiated uroid region. The flagellate has 2 flagella, which emerge anteriorly and are equal in length. It has a ventral cytostome near the anterior border. The cyst is helmet-shaped and without opercula. Polar masses are present during nuclear division.     

The Use of Polyvalent Sera for the Serotyping of Mycobacteria within the Mycobacterium avium– M. intracellulare-M. scrofulaceum Complex

A modification to Schaefer's agglutination method for serotyping mycobacteria within the Mycobacterium avium-M. intracellulare-M. scrofulaceum complex is described. The antigens are screened against polyvalent sera and subsequently a reduced range of absorbed antisera. This expedites the serotyping procedure and conserves expensive antiserum stocks.     

Critical Inuit Studies: An Anthology of Contemporary Arctic Ethnography

Critical Inuit Studies: An Anthology of Contemporary Arctic Ethnography . Pamela Stern and Lisa Stevenson, eds. Lincoln: Nebraska University Press, 2006. 302 pp.     

Microgeographic distribution of immature Ixodes dammini ticks correlated with that of deer

In order to determine whether the small-scale distribution of immature Ixodes dammini Spielman et al. corresponds closely to the activity patterns of white-tailed deer, Odocoileus virginianus (Zimmerman), these relationships were examined in a site on Long Island, New York, U.S.A. We first determined the extent and temporal pattern of adult ticks feeding on deer by examining twenty-three resident deer tranquilized during September-December 1985. I. dammini adults infested deer throughout this fall period, most abundantly during October and November. With radio-telemetry collars attached to deer we determined the relative frequency that they occupied 0.25 ha quadrats of the study site. During the following summer, we examined white-footed mice, Peromyscus leucopus (Rafinesque), that inhabited these quadrats and removed immature ticks from each. 8975 larval and 163 nymphal I. dammini were removed from 208 mice trapped in forty-three such quadrats. The frequency of deer using these quadrats was positively correlated with both the number of larval and of nymphal ticks per mouse. These results suggest that risk of I. damminiborne zoonotic disease may be decreased by locally reducing deer density in sites that experience intense human activity.     

Protein Kinase C and Melanocyte Transformation

Melanoma cells which have been isolated from metastatic melanoma tissue are able to survive and proliferate in serum supplemented media. In contrast, normal human melanocytes require the presence of growth stimulators if they are to survive in culture. A tumor promotor, 12–0-tetradecanoyl-phorbol-13-acetate (TPA) and substances that increase intracellular levels of cyclic-adenosine-monophosphate (cAMP), such as cholera toxin or isobutylmethyl xanthine, have been widely used for this purpose. The phorbol diester receptor was shown in 1982 to be the phospholipid- and calcium-dependent enzyme protein kinase C (PKC). We therefore directed our studies to the role of PKC regulation in the growth of normal human melanocytes and their transformation. Our studies show that while melanoma cells are inhibited by TPA, the growth of normal melanocytes is stimulated in a dose-dependent manner. The inhibitor, 1-(5-isoquinolinesulfonyl)-2-methyl-piperizine dihydrochloride (H7), which has been found to be the most specific for PKC, had no effect on the growth of normal melanocytes, but inhibited the growth of melanoma cells in a dose-dependent manner. PKC was isolated from the membrane and cytosol of normal melanocytes and melanoma cells. The basal (resting) levels of PKC activity in normal melanocytes was low compared to that measured in melanoma cells, and after short-term (1 hour) treatment with TPA the PKC activity was greatest at the membrane, with the activity decreasing the cytosol. Upon prolonged (48 hours) treatment with TPA, this redistribution of activity continued in normal melanocytes and the total activity increased. In melanoma cells, however, the total PKC activity decreased, particularly in the membrane fraction. A difference in activity and distribution of the enzyme was also seen after short-term (1 hour) treatment with H7. There was very little effect seen on PKC in normal melanocytes; however, the effect on melanoma cells was similar to that seen after 48 hours of exposure to TPA with a decrease in total activity, particularly in the membrane fraction. These results indicate that the regulation of PKC, in particular its activation by TPA, is altered during the transformation of normal human melanocytes     

The Influence of Carbon Dioxide and Daily Photon-flux Density on Optimal Leaf Nitrogen Concentration and Root: Shoot Ratio

Using a cost-benefit model, the leaf nitrogen concentrationand root : shoot ratio that maximize whole-plant relative growthrate are determined as a function of the above-ground environment(integrated daily photon flux density and the concentrationof carbon dioxide at the site of fixation within the leaf).The major advantage of this approach is that it determines theadaptive significance of leaf physiology by considering thefunctional integration of leaves and roots. The predicted responseto increasing daily photon flux densities is an increase inoptimal leaf N concentration (N_opt) and a concomitant increasein root: shoot ratio. Increased carbon dioxide concentrations,on the other hand, reduce N_opt and only slightly change root:shoot ratio. The observed increase in leaf nitrogen concentrationfound in plants growing at high altitudes (low CO₂ partial pressure)is also predicted. Since these responses to light and CO₂ maximizethe whole-plant relative growth rate, the observed adjustmentsthat plants make to light and carbon dioxide concentration appearto be adaptive. We show that the relationship between photosynthesis and leafnitrogen concentration is complex and depends on the light andCO₂ levels at which photosynthesis is measured. The shape ofthis function is important in determining N_opt and the oppositeresponse of leaf nitrogen to light and carbon dioxide is shownto be the result of the different effects of light and CO₂ onthe photosynthesis-leaf nitrogen curve. Plant growth, photosynthesis, leaf nitrogen, biomass allocation, optimization, carbon dioxide light     

Permeability to Water of the Fibre Cell Wall Material of Two Hardwoods

The permeability to water of the fibre cell wall of birch (Betulapubescens Ehrh.) and lime (Tilia x vulgaris Hayne) wood, wasmeasured in wood slices in which most of the void space wasfilled with paraffin wax or a polymerizing silicone elastomer.An osmotic technique was used with solutes of molecular weightgreat enough to prevent their molecules from penetrating thepores in the water-swollen cell wall. The solutes used weredextran and polyethylene glycol with molecular weights of 40000 and 6000 respectively. Values for permeability k x 10²¹, as defined by the Darcy equation,ranged between 3.6 m² for the tangential direction in birch,to 27 m² for the longitudinal direction in birch. These resultsare in good agreement with previously measured values but areat least ten times less than theoretical values. It is calculatedthat total emptying or filling of a wood cell through the wallmight be possible in as little as 5 min under a pressure differenceof 0.1 MPa if other flow pathways were blocked. Key words: Betula pubescens, Tilia x vulgaris, Water permeability, Fibre cell wall