Ethnohistory, genetics and simulation are used to propose a new ‘budding model’ to describe the historical processes by which complex irrigation communities may come into existence. We review two alternative theories, Wittfogel’s top-down state-formation theory and common-pool resource management, and suggest that a budding model would better account for existing archaeological and ethnographic...

BACKGROUND Establishing a new prognostic factor for early-stage cancer may seem difficult due to the small number of disease-specific deaths. Tumor budding has been recognized as a useful microscopic finding reflecting biological activity of the tumor. METHODS Tumor budding stand for isolated single cancer cells and cell clusters scattered beyond the tumor margin at the invasive front. It was...

In this issue, reveal that different meiotic recombination mechanisms predominate in fission yeast and budding yeast. Budding yeast usually form crossover recombinants through double Holliday junctions, whereas fission yeast unexpectedly appear to form crossover recombinants through single junctions.

Animal cells secrete small vesicles, otherwise known as exosomes and microvesicles (EMVs). A short, N-terminal acylation tag can target a highly oligomeric cytoplasmic protein, TyA, into secreted vesicles (Fang, Y., Wu, N., Gan, X., Yan, W., Morell, J. C., and Gould, S. J. (2007) PLoS Biol. 5, 1267-1283). However, it is not clear whether this is true for other membrane anchors or other highly o...

The membrane scission event that separates nascent enveloped virions from host cell membranes often requires the ESCRT pathway, which can be engaged through the action of peptide motifs, termed late (L-) domains, in viral proteins. Viral PTAP and YPDL-like L-domains bind directly to the ESCRT-I and ALIX components of the ESCRT pathway, while PPxY motifs bind Nedd4-like, HECT-domain containing, ...

Current models of HIV-1 morphogenesis hold that newly synthesized viral Gag polyproteins traffic to and assemble at the cell membrane into spherical protein shells. The resulting late-budding structure is thought to be released by the cellular ESCRT machinery severing the membrane tether connecting it to the producer cell. Using electron tomography and scanning transmission electron microscopy,...