When faced with environmental changes, microbes often enter a temporary growth arrest during which they reprogram the expression of specific genes to adapt to the new conditions. A prime example of... Show moreWhen faced with environmental changes, microbes often enter a temporary growth arrest during which they reprogram the expression of specific genes to adapt to the new conditions. A prime example of such a lag phase occurs when microbes need to switch from glucose to other, less-preferred carbon sources. Despite its industrial relevance, the genetic network that determines the duration of the lag phase has not been studied in much detail. Here, we performed a genome-wide Bar-Seq screen to identify genetic determinants of the Saccharomyces cerevisiae glucose-to-galactose lag phase. The results show that genes involved in respiration, and specifically those encoding complexes III and IV of the electron transport chain, are needed for efficient growth resumption after the lag phase. Anaerobic growth experiments confirmed the importance of respiratory energy conversion in determining the lag phase duration. Moreover, overexpression of the central regulator of respiration, HAP4, leads to significantly shorter lag phases. Together, these results suggest that the glucose-induced repression of respiration, known as the Crabtree effect, is a major determinant of microbial fitness in fluctuating carbon environments. Show less
Ploeg, J. van der; Vermeersch, L.; Rodriguez, D.; Balbas, M.; Weerd, M. van 2017
This paper describes the efforts to establish a network of community-conserved areas in the municipality of San Mariano on Luzon, with the dual aim to protect the Philippine crocodile and to... Show moreThis paper describes the efforts to establish a network of community-conserved areas in the municipality of San Mariano on Luzon, with the dual aim to protect the Philippine crocodile and to improve inland fisheries. The necessary steps to establish a community-conserved area are summarized, and their sustainability assessed. The importance of local leadership and democratic decision-making processes in the design of community-based conservation measures is highlighted, and it is argued that implicit cultural values, such as hospitality and respect, are often a more important motivation for rural communities to protect aquatic resources than explicit concerns about food security and livelihoods. Show less
