Changes in plasma tryptophan and melatonin content in penned sheep

The present study was undertaken to examine the relationship between the plasma levels of melatonin and its precursor tryptophan. No circadian changes in plasma total tryptophan content were evident which could be related to the marked night-time rise in plasma melatonin. An automated programmable blood sampling device suited to studies of circadian rhythms in blood constituents is described.     

Characterisation of ovine Bordetella parapertussis isolates by analysis of specific endotoxin (lipopolysaccharide) epitopes, filamentous haemagglutinin production, cellular fatty acid composition and antibiotic sensitivity

Abstract Isolates of Bordetella parapertussis , recovered from sheep or man, were characterised by reaction with specific anti- Bordetella lipopolysaccharide monoclonal antibodies, production of filamentous haemagglutinin, fatty acid patterns, and antibiotic sensitivity. Generally, the isolates lay within one of four groups, with separation of the ovine isolates into two groups. Reactions with specific monoclonal antibodies against lipopolysaccharide separated the ovine isolates into these two groupings. Analysis of the cellular fatty acid compositions by cluster analysis differentiated between the human and the ovine strains and also showed variation within the ovine isolates. When the production of filamentous haemagglutinin was analysed in an ELIS A system, a similar pattern emerged. Varying concentrations of filamentous haemagglutinin (11–429 ng (mg total protein)⁻¹) were extracted from the human isolates and the one group of ovine isolates with no significant protein detected in the other ovine group. These studies demonstrate variation between and within B. parapertussis isolates recovered from two mammalian sources.     

Stage‐dependent physiological responses in a butterfly cause non‐additive effects on phenology

Studies illustrating climate‐induced shifts in phenology typically focus on the timing of a single lifecycle stage. In contrast, species’ responses to climate change are likely to be complex and constrained by interactions and tradeoffs across the lifecycle. We characterized the thermal sensitivity of egg, larval and pupal stages of a native Australian butterfly and then integrated these responses to predict sensitivity of emergence time, survival, and feeding performance on oviposition date and climate. Thermal physiology varied among lifecycle stages and between sexes, with the development rate of eggs, first instar larvae, and pupae being the most sensitive to temperature. As lifecycle stages have different thermal physiologies, the environment experienced by a given stage depends in a complex way on the experience of previous stages. Our simulations indicate that oviposition date strongly influences time spent in each lifecycle‐stage, as well as performance. Under a high emissions climate warming scenario (CSIRO Mk 3.5 climate model, high emissions SRES marker scenario A1F1, and a moderate rate of global warming), we predict development times to decrease by 38 days by 2070. Our analysis illustrates how differences in thermal physiology across the lifecycle may result in non‐additive effects on phenology which, in turn, may constrain species’ responses to global warming. These results highlight the need to view shifts in phenology in the context of an organism's entire lifecycle.     

Spatial Data Analysis of Regional Counts

Counts data from spatially continguous regions offer a challenge to the statistician both from the data analytic and the statistical modeling point of view. Important applications include epidemiological studies (e. g., cancer mortality over the counties of the USA) and Census surveys (e. g., undercount over the Census blocks of an urban area). It has long been recognized by time-series analysts that data close together in time usually exhibit higher dependence than those far apart. Time-series data analysis relies on methods of data transformation, detrending, and autocorrelation plotting. It is our intention in this article to generalize this approach to a spatial setting. To do this we consider a small spatial data set of 100 observations. Through the use of a square-root transformation, a weighted median polish and a variogram analysis of the median-polish residuals, we represent the transformed data as a trend plus stationary error. Thus we show how standard data-analytic techniques can be modified both to mitigate and to exploit the spatial relationships.     

Retardation of leaf senescence by urea cytokinins in Raphanus sativus

Approximately 500 urea derivatives and related compounds were tested for ability to retard leaf senescence as measured by chlorophyll retention in radish (Raphanus sativus) leaf discs. Of the 90 compounds found to be active, some had activity at 10^?6 M of the same order as kinetin. There was a high correlation between ability to promote chlorophyll retention and initiation of cell division. Highly active compounds had a planar ring and a HNCONH bridge; substitution with a HNCSNH bridge reduced activity and all other tested arrangements of the bridge gave inactive compounds. Substitution of both amino hydrogen atoms on one or both sides of the bridge reduced or removed activity. Some N′-substituted phenyl ureas were highly active. Introduction of a N-phenyl ring to a N-phenyl urea increased activity except where one ring was substituted in the para position with chloro, bromo or iodo. The activities of symmetrical disubstituted ureas were generally less than the corresponding N-monosubstituted derivative. The results suggest that the receptor site for cytokinin activity is the same for senescence retadation and cell division initiation.