A Comparative Study of 4 Strains of Hartmannellid Amoebae

SYNOPSIS. The biologic characteristics of 4 strains of hartmannellid amoebae were compared. All contained cytoplasmic DNA, degraded thymidine to CO₂ and killed chick embryos at 32 C. All except H. glebae secreted a lipogenic toxin and contained antigen(s) capable of sensitizing erythrocytes. A. castellanii , unlike the other 3, also killed chick embryos at 37 C. The Fernald strain of H. rhysodes differed from the other 3 in its higher cytoplasmic grain count of cells labelled with ³H-thymidine and in its ability to induce the appearance of amoebic antigen within human cells. Increased nuclear labelling in the Fernald strain was observed with increasing concentrations of ³H-thymidine.     

Top-down and bottom-up influences on populations of a stream detritivore

1. Knowledge of the influence of predatory fish in detritus‐based stream food webs is poor. We tested whether larval abundance of the New Zealand leaf‐shredding caddisfly, Zelandopsyche ingens (family Oeconesidae), was affected by the presence of predatory brown trout, Salmo trutta and the abundance of their primary detrital resource (Nothofagus leaves). 2. The density of Z. ingens and the biomass of leaves were determined in seven fishless streams and four trout streams in the Cass region, central South Island, on four occasions spanning 5 years. 3. Physicochemical conditions were similar in trout and fishless streams, but ancova indicated that Z. ingens numbers were positively related to leaf biomass and that caddisfly numbers were significantly greater in fishless streams than trout streams for any given biomass of leaf. The cases of trout stream larvae were also heavier per unit length than those in fishless streams. 4. Our results provide evidence for both top‐down and bottom‐up influences on a detritus‐based stream food web. Although stream detritivores may benefit from a habitat that provides both food and a degree of protection from predators, top‐down effects of predators on detritivore population abundance were still important. Thus, detrital resource availability may determine maximum attainable population size, whereas predation is likely to reduce the population to a level below that.     

c‐erbB‐2 and p53 expression in breast cancer fine needle aspirates

The aim of this study was to co‐evaluate c‐ erbB ‐2 and p53 protein expression in breast cancer fine needle aspirates (FNA) and to compare this with histological variables and the immunohistochemical phenotype of the tumours. Furthermore, we assessed the relationship of c‐ erbB ‐2 and p53 immunocytochemical expression to tumour prognostic factors. We examined 124 breast cancer FNAs and 79 matched surgical specimens using the avidin–biotin complex (ABC) and the alkaline phosphatase immunocytochemical techniques. C‐ erbB ‐2 immunopositivity was detected in 37.9% of the FNAs, while 31.7% were positive for p53. A statistically significant correlation was observed between p53 negativity and absence of c‐ erbB ‐2 immunostaining in the FNAs ( P =0.0007). Smears from infiltrating ductal carcinomas tended to be more frequently positive for p53 (36.7%) than those from lobular carcinomas (11.7%) ( P =0.054). In matched tumour tissues, c‐ erbB ‐2 was positive in 16.7% and p53 in 19% of cases. The immunocytochemical results for both c‐ erbB ‐2 and p53 were significantly correlated with the immunohistochemical results. There was no correlation between c‐ erbB ‐2 and p53 immunostaining, in both FNAs and tissues, and patients' menopausal status, tumour size, grade and lymph node status.     

MIND-SETS OF THE WINE CONSUMER

This paper presents the results from a study of consumer reactions to different attributes of red and white wine, with stimuli presented in the form of small, experimentally designed, test concepts (conjoint measurement). The results show that possibly four consumer mind-sets exist, with each mind-set comprising a different set of communication drivers for concept acceptance. Most subjects fit into one of three key categories; "Classics" (who want their wines to be traditional), "Imaginers" (who want to get into the drinking experience through knowing details about their wines) or "Elaborates" (who want their wines to produce many sensations and flavors). A fourth group (No Frills), were interested in simple and safe wines without any detail of flavor or origin. This segment was found in the red wine study, but not in the white wine study.     

Characterization of 17 microsatellite loci in the Japanese land snail genera Mandarina,Ainohelix, and Euhadra (Mollusca,Gastropoda, Pulmonata)

Land snails of the genera Mandarina, Euhadra and Ainohelix are useful for understanding the ecology and evolution of speciation and adaptation, so we have developed 17 microsatellite loci for these species. As in other land snails, most of the loci are highly polymorphic compound repeats, with a great size range between alleles. The loci should be useful in understanding gene‐flow, genetic structure and speciation in these species.     

The influence of predatory fish on mayfly drift: extrapolating from experiments to nature

1. A knowledge of how individual behaviour affects populations in nature is needed to understand many ecologically important processes, such as the dispersal of larval insects in streams. The influence of chemical cues from drift‐feeding fish on the drift dispersal of mayflies has been documented in small experimental channels (i.e. < 3 m), but their influence on dispersal in natural systems (e.g. 30 m stream reaches) is unclear. 2. Using surveys in 10 Rocky Mountain streams in Western Colorado we examined whether the effects of predatory brook trout (Salvelinus fontinalis) on mayfly drift, that were apparent in stream‐side channels, could also be detected in natural streams. 3. In channel experiments, the drift of Baetis bicaudatus (Baetidae) was more responsive to variation in the concentration of chemical cues from brook trout than that of another mayfly, Epeorus deceptivus (Heptageniidae). The rate of brook trout predation on drifting mayflies of both species in a 2‐m long observation tank was higher during the day (60–75%) but still measurable at night (5–10%). Epeorus individuals released into the water column were more vulnerable to trout predation by both day and night than were Baetis larvae treated similarly. 4. Drift of all mayfly taxa in five fishless streams was aperiodic, whereas their drift was nocturnal in five trout streams. The propensity of mayflies to drift was decreased during the day and increased during the night in trout streams compared with fishless streams. In contrast to the channel experiments, fish biomass and density did not alter the nocturnal nature nor magnitude of mayfly drift in natural streams. 5. In combination, these results indicate that mayflies respond to subtle differences in concentration of fish cues in experimental channels. However, temporal and spatial variation in fish cues available to mayflies in natural streams may have obscured our ability to detect responses at larger scales.