Effects of pertussis toxin on alpha 1-agonist-mediated phosphatidylinositide turnover and myocardial cell hypertrophy in neonatal rat ventricular myocytes

In neonatal rat ventricular myocytes pretreatment with pertussis toxin did not affect 1 microM (-)-norepinephrine stimulation of inositol phosphates or myocardial cell hypertrophy as measured either by protein radiolabelling or by myocardial cell protein content. Thus guanine nucleotide protein(s) ADP-ribosylated by pertussis toxin do not play a role in two alpha 1-adrenoceptor-mediated processes, phosphatidylinositide turnover and induction of myocardial cell hypertrophy.     

Krameria, free fatty acids and oil-collecting bees

Vogel's report of the production of glycerides rather than nectar as rewards gathered by bees described an association involving several genera of insects and numerous plant families. We report here that members of the Krameriaceae produce floral lips more unusual than those described by Vogel. Our data also provide evidence that the oils of Krameria are collected by bees of only one genus, Centris (Anthophoridae), and used, mixed with pollen, as larval food.     

Stability and change in ethnic groups in England and Wales

The Office for National Statistics (ONS) Longitudinal Study (LS) is an exceptional resource for exploring dynamic processes in individuals' lives for a representative sample of the population of England and Wales and across a thirty year period, including how those processes vary by ethnic group. However, analyses tend to assume a certain stability in the meaning of the ethnic group being studied: the insights into ethnic group differentiation are premised on the fact that the group has the same meaning over time. Here we show how the LS allows us to challenge such notions of group stability. This has practical implications for the ways we measure and conceive of Britain's minority ethnic groups. We illustrate this point with two examples: one exploring the change in ethnic group identification by the same individuals between 1991 and 2001, and the second exploring how loss to follow up is differentially experienced according to ethnic group. We provide some suggestions on the implications of this ethnic group instability for other research.     

Implications for prediction and hazard assessment from the 2004 Parkfield earthquake

Obtaining high-quality measurements close to a large earthquake is not easy: one has to be in the right place at the right time with the right instruments. Such a convergence happened, for the first time, when the 28 September 2004 Parkfield, California, earthquake occurred on the San Andreas fault in the middle of a dense network of instruments designed to record it. The resulting data reveal aspects of the earthquake process never before seen. Here we show what these data, when combined with data from earlier Parkfield earthquakes, tell us about earthquake physics and earthquake prediction. The 2004 Parkfield earthquake, with its lack of obvious precursors, demonstrates that reliable short-term earthquake prediction still is not achievable. To reduce the societal impact of earthquakes now, we should focus on developing the next generation of models that can provide better predictions of the strength and location of damaging ground shaking.     

Nucleosome positioning can affect the function of a cis-acting DNA element in vivo

Positioning of nucleosomes has been proposed as one mechanism whereby the activity of DNA is regulated: cis-acting elements located in linker DNA might be more accessible for interaction with trans-acting protein factors than they would be if they were directly associated with histones in nucleosome core particles. The eleven base pairs constituting the autonomously replicating sequence (ARS) of the high-copy-number TRP1ARS1 plasmid of Saccharomyces cerevisiae are located in a linker region near the edge of a positioned nucleosome and form an origin of replication. Could nucleosome positioning render the ARS accessible for interaction with the proteins necessary for its function? I have tested this hypothesis by making deletions and an insertion to move the ARS into the nucleosome DNA and then examining the effects on ARS function. There is a marked decrease in copy number when the ARS is moved into the central DNA region of the nucleosome core particle, a region known to differ in structure and stability from the peripheral segments of nucleosome DNA.