Culture in sustainable infrastructure

The high failure rate of infrastructures around the world is alarming, most especially when such failures constrain economic growth and development. In most cases, existing institutions or strategies designed to maintain and reproduce effective infrastructures in areas that lack them have been mostly unsuccessful, particularly in sub-Saharan Africa. A carefully conducted survey covering the six geopolitical zones in Nigeria confirms the low-level stability, supply, quality and maintenance of infrastructure and its services. Using the severity index in matrix order model developed in this study, major factors responsible for unsustainable infrastructure delivery and failures are identified. The paper further argues that these major factors are interrelated rather than being peculiar to Nigeria or sub-Saharan Africa. Suffice it to say that the effects of these problems are widespread and of global impact. However, what cuts across all the major factors responsible for unsustainable infrastructure delivery and high failure rates are gross institutional lapses. In view of the fact that sustainable infrastructure is essential for sustainable development, this paper emphasises the uniqueness of the recipients' cultures and values alongside the integration of indigenous communities and infrastructure users: from conceptualisation to delivery within the framework for institutional building and sustainable infrastructure provision

Alnus peptides modify membrane porosity and induce the release of nitrogen-rich metabolites from nitrogen-fixing Frankia.

International audienceActinorhizal plant growth in pioneer ecosystems depends on the symbiosis with the nitrogen-fixing actinobacterium Frankia cells that are housed in special root organs called nodules. Nitrogen fixation occurs in differentiated Frankia cells known as vesicles. Vesicles lack a pathway for assimilating ammonia beyond the glutamine stage and are supposed to transfer reduced nitrogen to the plant host cells. However, a mechanism for the transfer of nitrogen-fixation products to the plant cells remains elusive. Here, new elements for this metabolic exchange are described. We show that Alnus glutinosa nodules express defensin-like peptides, and one of these, Ag5, was found to target Frankia vesicles. In vitro and in vivo analyses showed that Ag5 induces drastic physiological changes in Frankia, including an increased permeability of vesicle membranes. A significant release of nitrogen-containing metabolites, mainly glutamine and glutamate, was found in N2-fixing cultures treated with Ag5. This work demonstrates that the Ag5 peptide is central for Frankia physiology in nodules and uncovers a novel cellular function for this large and widespread defensin peptide family