has adopted four "bench top" bioassays which do not require higher animals to screen and direct the fractionation of botanical extracts in drug discovery ejfons. These are: 1. The brine shrimp lethality test (BST) (a general bioassay), 2. The inhibition of crown gall tumors on discs of potato tubers (an antitumor bioassay), 3. The inhibition of frond proliferation in duckweed (a bioassay for herbicides and plant growth stimulants), and 4. The yellow fever mosquito larvae lethality test (a bioassay for pesticides). The materials and procedures for those bioassays will be briefly described. The authors' results in applying these simple methods in the discovery of Annonaceous acetogenins will be presented to illustrate their successful use. The BST is especially suggested as an inexpensive, simple, and rapid means of standardization of bioactivity in heterogeneous botanical products.
Simple bench‐top bioassays involving brine shrimp lethality, Lemna frond proliferation, and the inhibition of crown gall tumours on potato discs, as well as the human tumour cell lines A‐549 lung carcinoma, MCF‐7 breast carcinoma and HT‐29 colon adenocarcinoma, were compared for their accuracy to detect known in vivo (P‐388) active antitumour agents supplied by the National Cancer Institute. The potato disc assay was the best and showed excellent correlation to in vivo activity (p=0.008). The brine shrimp assay (p = 0.033) proved to be superior or equally as accurate as the in vitro human solid tumour cell lines (p = 0.033‐0.334). The Lemna assay (p = 0.708) showed the poorest correlation. The brine shrimp and potato disc assays are suggested as convenient in‐house prescreens to existing cytotoxicity or antitumour assays.
entire season. Chlorosis generally occurs in patchy areas of fields and frequently, but not always, in low areas.
Iron deficiency chlorosis is a common, yield-limiting condition forFranzen and Richardson (2000) showed that chlorotic soybean [Glycine max (L.) Merr.] grown in areas with high-pH, calcareous soils. The objectives of this study were to document the extent patches did not occur in a pattern consistent with of chlorosis in an area of the upper Midwest, to understand producers' changes in soil type.perceptions and management practices related to Fe deficiency chloro-
Screening of crude extracts of the bark of Annona bullata showed cytotoxic and pesticidal activities. By monitoring with brine-shrimp lethality, two novel, extremely potent acetogenins, bullatacin [1] and bullatacinone [2], were isolated. Spectral and chemical methods identified bullatacin as a diastereomer of asimicin. Bullatacinone represents bullatacin with the lactone cleaved and reformed at the 4-OH. Compounds 1 and 2 show selective cytotoxicities in human tumor cell lines, and certain susceptible cells give ED50 values as low as 10(-12)-10(-15) micrograms/ml. Bullatacin was pesticidal at concentrations as low as 1 ppm, but bullatacinone lacked pesticidal activities. The known compounds liriodenine and (-)-kaur-16-en-19-oic acid were also isolated and were lethal to brine shrimp but were not significantly cytotoxic.
Highlights We systematically assess the relationships between economic preferences and personality traits. We analyze a large set of adult non-student subjects with data on several life outcomes. Personality traits statistically predict outcomes as well or better than economic preferences. Decision theory and personality variables are meaningfully statistically related. Neuroticism and cognitive ability together explain much of risk preferences.Abstract: Economics and trait-based personality psychology have taken different approaches to understanding individual differences. The former emphasizes variables measured according to formal decision theory; the latter instead emphasizes variables derived from the factor analysis of trait assessments.In a data set on trainee truckers in a large US company, we provide a systematic assessment of the empirical pattern of relationships and correlations between the measurements used in these two approaches by comparing the predictive power of variables derived from personality theory and decision theory for several individual characteristics and outcomes, and relating the two sets of measurements to each other.We show that personality traits have a comparable or stronger statistical predictive power than do economic preferences for several dependent variables, including credit score, job persistence, and heavy truck accidents. They also have strong predictive power for Body Mass Index (BMI) and smoking status. Further, decision theory and personality variables are meaningfully related. For example, we confirm that cognitive ability explains a substantial part of time preferences, and find that Neuroticism and cognitive ability and together explain attitudes toward risk. In an experimental game, cognitive skills and Agreeableness explain important aspects of strategic behavior.
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