Cell transformation as aberrant differentiation：Environmentally dependent spontaneous transformation of NIH 3T3 cells

NIH 3T3 cells, a mouse fibroblast cell line used as routine target cells for transfection experiments, undergo spontaneous transformation in our experiments after they form a confluent sheet in medium containing fetal bovine serum (FBS) or lower coneentration of calf serum (CS). The transformation takes the form of foci of multiplying cells among the surrounding cells which have stopped cell division. However, no focus of transformed cells could be seen in medium containing high concentration (10％) of CS. Further experiments indicated that the frequency of transformation is highly dependent on the concentration of serum and the transformation in CS is changeable when the cells are passaged in FBS. 3~H-thymidine autoradiography has been proved to be a sensitive measurement indicator for focus formation. Our results suggest that the high frequency of transformation and its dependence on confluency as well as on medium composition are characteristics of cell differentiation rather than mutation. The role of the NIH 3T3 cell line as a cancer-initiated cell population and its accelerated transformation by ras oncogene might be considered as a form of tumor promotion is discussed.     

Fine-Structural Aspects of Microgametogenesis of Eimeria magna in Rabbits and in Kidney Cell Cultures*

SYNOPSIS. The fine-structural aspects of development of microgamonts of Eimeria magna were studied in kidney cell cultures and in experimentally infected rabbits. Spheroidal masses of gamont-like cytoplasm containing ribosomes, polyribosomes, and amylopectin granules were found within the parasitophorous vacuole; these bodies were apparently pinched off the surface of the gamont. Nucleoli were present in the early stages of nuclear division but disappeared as development proceeded. Spindles were eccentric and the nuclear membrane always remained intact in dividing nuclei. Nuclei eventually became elongate in shape, compact, and electron dense at the end oriented toward the periphery and lucent centrally. Usually, only the dense portion was incorporated into the gamete as the gamete developed by protruding from the gamont surface. Fullyformed microgametes were biflagellate and contained a nucleus, a mitochondrion, and 8-10 microtubules. Multiple-membrane complexes, which apparently originated from the nuclear envelope or endoplasmic reticulum, were found within the gamont residual body. Occasionally, 2 or 3 micro- and/or macrogamonts were seen within the same cell. In some cells one or 2 micro- or macrogamonts as well as several merozoites were present in the same parasitophorous vacuole.     

EVALUATION OF WINE QUALITY USING A SMALL-PANEL HEDONIC SCALING METHOD

A hedonic scoring method for evaluating wines with a small panel was examined for reliability, effects of training level and agreement with a traditional 20-point scoring technique. The method was found to differentiate among qualities of 14 domestic Sauvignon Blanc wines with good reliability. Four panels were tested, three with a high degree of experience in wine judging and a fourth consisting of fine wine consumers with no special training. The three experienced panels agreed well about the wines' quality scores. Mean panel scores were less highly correlated (although still positive) with the untrained panel, which showed higher variability and lower reliability. Mean scores from the hedonic method were correlated at r =+0.94 with mean scores from a 20-point quality judging procedure. The small panel hedonic method is suitable for generating quality scores for consumer guidance in large scale wine surveys, as are commonly found in popular wine periodicals.     

Effects of Abscisic Acid on Nucleic Acid Synthesis and the Induction of Nitrate Reductase in Lemna polyrhiza

Abscisic acid (ABA) at low concentrations brings about the formationof turions (dormant fronds) in Lemna polyrhiza within 3 to 5days after application. The incorporation of ³H-thymidine intoDNA, separated by polyacrylamide-gel electrophoresis, is inhibitedby 80 to 90 per cent within 1 to 3 h of ABA application. Theincorporation of ¹⁴C-orotate and ³²P into RNA is not inhibiteduntil 3 to 9 h after ABA application, but 70 per cent inhibitionis reached after 24 h on 10^–5 M ABA. There is little inhibitionof ¹⁴C-leucine incorporation into protein until 2 to 3 daysafter application of ABA. The capacity of nitrate to inducenitrate reductase in cultures previously grown on nitrate-freemedium is not affected by ABA even up to 3 days after application.The results are discussed in relation to the mode of actionof ABA.     

Loss and Recovery of Phenotypic Expression of Gross Leukaemia Virus

MEASUREMENTS reported by Klein and Phelps¹ and by Glasel² have been interpreted to cast doubt on the conclusion from previous nuclear magnetic resonance (NMR) studies^3–5 that water in neural and muscle tissue possesses more average structure than liquid water. This communication intends to point out that the data in these two articles provide no basis for such doubt.     

Plant trait responses to grazing – a global synthesis

Herbivory by domestic and wild ungulates is a major driver of global vegetation dynamics. However, grazing is not considered in dynamic global vegetation models, or more generally in studies of the effects of environmental change on ecosystems at regional to global scale. An obstacle to this is a lack of empirical tests of several hypotheses linking plant traits with grazing. We, therefore, set out to test whether some widely recognized trait responses to grazing are consistent at the global level. We conducted a meta‐analysis of plant trait responses to grazing, based on 197 studies from all major regions of the world, and using six major conceptual models of trait response to grazing as a framework. Data were available for seven plant traits: life history, canopy height, habit, architecture, growth form (forb, graminoid, herbaceous legume, woody), palatability, and geographic origin. Covariates were precipitation and evolutionary history of herbivory. Overall, grazing favoured annual over perennial plants, short plants over tall plants, prostrate over erect plants, and stoloniferous and rosette architecture over tussock architecture. There was no consistent effect of grazing on growth form. Some response patterns were modified by particular combinations of precipitation and history of herbivory. Climatic and historical contexts are therefore essential for understanding plant trait responses to grazing. Our study identifies some key traits to be incorporated into plant functional classifications for the explicit consideration of grazing into global vegetation models used in global change research. Importantly, our results suggest that plant functional type classifications and response rules need to be specific to regions with different climate and herbivory history.     

Structural and Decision-Making Models: A Political Example

In this paper decision and structural models are distinguished on conceptual and empirical grounds. At one level of analysis the two models discharge different functions and apply to distinct logical universes. At another level, the two models apply to similar kinds of "reality." Political data from a village in India provides an example of the application of these models at both levels of analysis. Finally, propositions are formulated that clarify the employment of these models for other kinds of data.     

ACADEMIC VS. INDUSTRIAL PERSPECTIVES ON SENSORY EVALUATION

The current practice of sensory evaluation occurs in two general settings: the academic environment of a university laboratory and within the foods and consumer products industries. Sensory evaluation programs can differ in orientation, objectives, methodology and context, and viewed from the perspective of Brinberg's tripartite validity theory, focusing on experimental, theoretical and empirical paths. Differences in organizational goals and resources between academia and industry result in different uses of panels, statistics and collaborative efforts. Opportunities for advancement of the field of sensory science exist within the framework of academic training of and industrial demand for sensory professionals.     

SENSITIVITY OF THE ABX DISCRIMINATION TEST

The ABX test or matching-to-sample is a discrimination procedure involving presentation of both test and control items, and then presentation of one of the two items as a blind sample. The third (blind sample) must then be identified correctly to match it to the one correct alternative from the inspection phase. We hypothesized that the ABX test might have an advantage over other discrimination methods due to a warm-up effect arising from the inspection phase containing both test and control items. Furthermore, the ABX test might prove generally useful like the triangle test since it can be used when there is no specified attribute to be discriminated. The ABX test was compared to several other discrimination procedures. No advantage was observed in a variety of stimuli varying in complexity and in the difficulty of the discrimination.     

THRESHOLDS AND SUPRATHRESHOLD INTENSITY FUNCTIONS FOR CAPSAICIN IN OIL AND AQUEOUS BASED CARRIERS

Thresholds and responses to capsaicin in oil- and water-based model systems were compared. Thresholds were measured among 23 individuals using an ascending forced choice method of limits. Detection thresholds were 11.75 (± 1.31) mg/L in oil and 0.31 (± 0.03) mg/L in water. A horizontal labeled magnitude scale was used to obtain suprathreshold scaling functions in corn and soybean oils and in water systems using an emulsifier (polysorbate) or alcohol to solvate the capsaicin. In the water-based systems, capsaicin ranged from weak to very strong ratings over a range of 0.3 to 10 mg/L while the same perceptual range was achieved in oil over a range of 10 to 316 mg/L. Nonconsumers of hot/spicy foods generally had higher thresholds and higher suprathreshold responses in oil systems. Differences between user groups were less pronounced in water-based stimuli.