Approaching a state shift in Earth's biosphere

Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a planetary-scale 'tipping point' highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales, and by detecting feedbacks that promote such transitions. It is also necessary to address root causes of how humans are forcing biological changes.     

Evolutionary genomics: codon bias and selection on single genomes

The idea that natural selection on genes might be detected using only a single genome has been put forward by Plotkin and colleagues, who present a method that they claim can detect selection without the need for comparative data and which, if correct, would confer greater power of analysis with less information. Here we argue that their method depends on assumptions that confound their conclusions and that, even if these assumptions were valid, the authors' inferences about adaptive natural selection are unjustified.     

Infective transmission and characterisation of a C-type virus released by cultured human myeloid leukaemia cells.

A C-type virus isolated from long term cultures of myeloid cells from a patient with acute myelogenous leukaemia is infectious for a wide variety of cells. The establishment of chronically infected cells enabled us to characterise the virus by biological, immunological, and biochemical tests. The virus is closely related to the simian sarcoma-associated virus isolated from a woolly monkey fibrosarcoma.     

Compound 48/80 decreases adenosine 3′5′-monophosphate formation in rat peritoneal mast cells

Zusammenfassung Präparat 48/80 unterdrückt die Bildung von 3,5-AMP aus Adenin in isolierten peritonealen Mastzellen. Es konnte keine zeitliche Verschiebung zwischen dieser Unterdrückung und der Histamin freisetzenden Wirkung von Präparat 48/80 festgestellt werden.

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This investigation was supported by United States Public Health Service Grant GM 13016 from the National Institute of General Medical Sciences.