Littoral Acari of Marion Island: ecology and extreme wave action

Fourteen species of littoral Acari (Arachnida) were collected from the shores of sub-Antarctic Marion Island, of which Parasitiphis brunneus (Kramer) (Ologamasidae), Rhombognathus apsteini Lohmann and R. gressitti Newell (Halacaridae) are new to the Prince Edward Islands. Acari, impoverished both in terms of diversity and abundance, were confined to the few micro-habitats, including rocky-shore lichens, kelp holdfasts, other macroalgae and the surface pitting of mobile boulders, which provided protection from the direct and indirect stresses of severe wave action.     

Characterization of human monocyte activation by a water soluble preparation of Aphanizomenon flos-aquae.

Aphanizomenon flos-aquae (AFA) is a fresh-water microalgae that is consumed as a nutrient-dense food source and for its health-enhancing properties. The current research characterizes the effect of a water soluble preparation from AFA on human monocyte/macrophage function and compares the effect of AFA with responses from known agents that modulate the immune system. At 0.5 μg/ml the AFA extract robustly activated nuclear factor kappa B (NF-kappa B) directed luciferase expression in THP-1 human monocytic cells to levels at 50% of those achieved by maximal concentrations (10 μg/ml) of bacterial lipopolysaccharide (LPS). In addition, the AFA extract substantially increased mRNA levels of interleukin-1β(IL-1β) and tumor necrosis factor-(TNF-), and enhanced the DNA binding activity of NF-kappa B. The effects of AFA water soluble preparation were similar to the responses displayed by LPS, but clearly different from responses exhibited by tetradecanoyl phorbol acetate (TPA) and interferon-gamma (INF-γ). Pretreatment of THP-1 monocytes with factors known to induce hyporesponsiveness suppressed both AFA-dependent and LPS-dependent activation. These results suggest that the macrophage-activating properties of the AFA water soluble preparation are mediated through pathways that are similar to LPS-dependent activation.     

Multivariate analysis of surface water characteristics in the summer regime of the western Irish Sea

A part of the western Irish Sea is strongly stratified during the summer months, with the boundary of stratification marked by a front with horizontal temperature gradients. Continuous on-line analysis has been used to record the surface water variability of nine characteristics along a cruise path in this area.Multivariate analysis (principal component) indicates the presence of four distinct water types separated by thermal gradients. Two of these water types show land mass influence and two illustrated the effects of the mixed and stratified regimes. The stratified surface waters had a marked degree of homogeneity with respect to the measured characteristics, while the mixed surface waters exhibited greater variability. Marked micro-variations in chlorophyll a concentrations were observed in the latter water type.No consistent relationships were observed among the physical, chemical, and biological variables across the front because of the gradual change in the gross properties of the mixed surface water during its northward passage through the Irish Sea.     

Sample Size Determination for Grouped Exponential Observations: A Cost Function Approach

Calculating the required sample size for a desired power at a given type I error level, we often assume that we know the exact time of all subject responses whenever they occur during our study period. It is very common, however, in practice that we only monitor subjects periodically and, therefore, we know only whether responses occur or not during an interval. This paper includes a quantitative discussion of the effect resulting from data grouping or interval censoring on the required sample size when we have two treatment groups. Furthermore, with the goal of exploring the optimum in the number of subjects, the number of examinations per subject for test responses, and the total length of a study time period, this paper also provides a general guideline about how to determine these to minimize the total cost of a study for a desired power at a given α-level. A specified linear cost function that incorporates the costs of obtaining subjects, periodic examinations for test responses of subjects, and the total length of a study period, is assumed, primarily for illustrative purpose.     

Enzyme changes accompanying thermal acclimation in two species of pleurocerid snails.

Goniobasis cahawbensis is a stream snail that experiences an annual temperature cycle. G. cochliaris is limited in distribution to springs, and their immediate vicinities, which are characterized by nearly constant annual temperatures. The present study sought to determine whether temperature dependent biochemical differences exist that might account for the differential distribution of these congeneric pleurocerid snails. Eight enzymes were examined following acclimation to 10 degrees, 17 degrees and 24 degrees C. No significant temperature dependent qualitative differences in enzyme phenotypes were demonstrable in either species by starch-gel electrophoresis for malate dehydrogenase, glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, phosphoglucomutase, superoxide dismutase and acetyl and butyryl esterases. Significant quantitative differences were observed in three of these enzymes. G. cahawbensis cytosol malate dehydrogenase activity increased significantly with increasing acclimation temperature, while G. cochliaris malate dehydrogenase activity remained unchanged. The activities of glucose-6-phosphate dehydrogenase did not differ significantly between acclimation temperatures for either species; however, the overall activity of both enzymes was significantly higher for G. cochliaris. Appreciable levels of LDH activity were not demonstrable by electrophoresis or enzymatic assay.     

The Enzyme Droplets of Vertebrate Kidney

The properties and distribution of enzyme droplets of kidney, liver, and gut of several vertebrates were investigated. Qualitative and quantitative differences in enzyme content existed in droplets from different sources. There was usually a closer correlation between the properties of the inclusions and their tissue origin than between the droplets of different organs obtained from one animal. The most noticeable specific characteristic was the relatively low acid phosphatase content of the lizard tissues. In all animals the enzyme droplets of liver and gut were considerably smaller than those of the proximal region of the nephron. The collecting ducts of bird and lizard kidneys possessed droplets of a different composition from those of the proximal segment, these bodies were considered to be associated with external secretion rather than with renal function.