Internal lipid synthesis and vesicle growth as a step toward self-reproduction of the minimal cell

One of the major properties of the semi-synthetic minimal cell, as a model for early living cells, is the ability to self-reproduce itself, and the reproduction of the boundary layer or vesicle compartment is part of this process. A minimal bio-molecular mechanism based on the activity of one single enzyme, the FAS-B (Fatty Acid Synthase) Type I enzyme from Brevibacterium ammoniagenes, is encapsulated in 1-palmitoyl-2oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes to control lipid synthesis. Consequently molecules of palmitic acid released from the FAS catalysis, within the internal lumen, move toward the membrane compartment and become incorporated into the phospholipid bilayer. As a result the vesicle membranes change in lipid composition and liposome growth can be monitored. Here we report the first experiments showing vesicles growth by catalysis of one enzyme only that produces cell boundary from within. This is the prototype of the simplest autopoietic minimal cell

Changes in the variability and periodicity of precipitation in Scotland

This paper analyses the temporal and spatial changes in the amount and variability of rainfall in Scotland. The sequential Mann–Kendall test reveals that total annual precipitation has increased across Scotland since the 1970s with increasing trends in variability beginning between the mid-1960s and the mid-1970s. Whilst temporally consistent increasing trends in precipitation totals prevail in the West, many weather stations in the East have experienced subsequent trend turning points in the following two decades, explaining the larger magnitude of the trends in western Scotland in recent decades. Trend analyses on six measures of rainfall variability indicate an increase in rainfall variability during the period 1961–2000, as measured by the intra-annual variance, the winter to summer precipitation ratio and the annual cumulative sum range, with decreasing trends observed in the number of dry days. Periodicities associated with the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation could explain the observed temporal variability of rainfall

Spatial patterns and trends of daily rainfall regime in Peninsular Malaysia during the southwest and northeast monsoons : 1975-2004

This study focuses on describing the patterns and trends of five selected rainfall indices in Peninsular Malaysia, based on daily rainfall data from 1975 to 2004. Five rainfall indices based on two main seasons, the northeast and southwest monsoons, were analyzed: total rainfall, frequency of wet days, rainfall intensity, frequency of wet days (extreme frequency), and rainfall intensity (extreme intensity) exceeding the long-term mean 95th percentile. The findings indicated that the eastern areas of the Peninsula were strongly influenced by the northeast monsoon, while the southwest monsoon had the greatest impact on the western part of the Peninsula, particularly the northwest. In studying the trends of these rainfall indices, the non-parametric Mann-Kendall test was used. The serial correlation and cross-correlation structure of the data were accounted for in determining the significance of the Mann-Kendall test results. It was found that there were differences in trend patterns over the Peninsula during both seasons, with a decrease in total rainfall and a significant decrease in frequency of wet days leading to a significant increase in rainfall intensity over the Peninsula, except in eastern areas, during the southwest monsoon. In contrast, a trend of significantly increasing total rainfall and an increase in frequencies of extreme rainfall events during the northeast monsoon caused a significantly increasing trend in rainfall intensity over the Peninsula to be observed. However, no significant trend was observed with respect to extreme intensity during both monsoons over the Peninsula. The findings of this study suggest that rainfall patterns in Peninsular Malaysia are very much affected by the northeast monsoon, based on the larger magnitude of changes observed in the rainfall indices

Trends in temperature and rainfall extremes in the Yellow River source region, China

Spatial and temporal changes in daily temperature and rainfall indices are analyzed for the source region of Yellow River. Three periods are examined: 1960–1990, 1960–2000 and 1960–2006. Significant warming trends have been observed for the whole study region over all the three periods, particularly over the period 1960–2006. This warming is mainly attributed to a significant increase in the minimum temperature, and characterized by pronounced changes in the low temperature events composing a significant increase in the magnitude and a significant decrease in the frequency. In contrast to the temperature indices, no significant changes have been observed in the rainfall indices at the majority of stations. However, the rainfall shows noticeable increasing trends during winter and spring from a basin-wide point of view. Conversely, the frequency and contribution of moderately heavy rainfall events to total rainfall show a significant decreasing trend in summer. To conclude, this study shows that over the past 40–45 years the source region of the Yellow River has become warmer and experienced some seasonally varying changes in rainfall, which also supports an emerging global picture of warming and the prevailing positive trends in winter rainfall extremes over the mid-latitudinal land areas of the Northern Hemisphere.Water ManagementCivil Engineering and Geoscience