Chlamydia trachomatis Co-opts GBF1 and CERT to Acquire Host Sphingomyelin for Distinct Roles during Intracellular Development

The obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound inclusion that acquires host sphingomyelin (SM), a process that is essential for replication as well as inclusion biogenesis. Previous studies demonstrate that SM is acquired by a Brefeldin A (BFA)-sensitive vesicular trafficking pathway, although paradoxically, this pathway is dispensable for bacterial replication. This finding suggests that other lipid transport mechanisms are involved in the acquisition of host SM. In this work, we interrogated the role of specific components of BFA-sensitive and BFA-insensitive lipid trafficking pathways to define their contribution in SM acquisition during infection. We found that C. trachomatis hijacks components of both vesicular and non-vesicular lipid trafficking pathways for SM acquisition but that the SM obtained from these separate pathways is being utilized by the pathogen in different ways. We show that C. trachomatis selectively co-opts only one of the three known BFA targets, GBF1, a regulator of Arf1-dependent vesicular trafficking within the early secretory pathway for vesicle-mediated SM acquisition. The Arf1/GBF1-dependent pathway of SM acquisition is essential for inclusion membrane growth and stability but is not required for bacterial replication. In contrast, we show that C. trachomatis co-opts CERT, a lipid transfer protein that is a key component in non-vesicular ER to trans-Golgi trafficking of ceramide (the precursor for SM), for C. trachomatis replication. We demonstrate that C. trachomatis recruits CERT, its ER binding partner, VAP-A, and SM synthases, SMS1 and SMS2, to the inclusion and propose that these proteins establish an on-site SM biosynthetic factory at or near the inclusion. We hypothesize that SM acquired by CERT-dependent transport of ceramide and subsequent conversion to SM is necessary for C. trachomatis replication whereas SM acquired by the GBF1-dependent pathway is essential for inclusion growth and stability. Our results reveal a novel mechanism by which an intracellular pathogen redirects SM biosynthesis to its replicative niche

Beneficial microorganisms associated with sugarcane crops : the green gold for clean energy

Sugarcane is currently the economic basis of more than 100 countries, planted on over 25 million hectares worldwide. It has been considered one of the most promising crops for generating clean and renewable energy and is expected to become the second largest energy source in the world by 2030. The global production of this crop is continuously growing, mostly because of the rising consumption of sugar and ethanol. Increases in both crop area plantations and yield are occurring to meet the growing demand. As sugarcane plants establish associations with a great diversity of microorganisms during their life cycle, the use of beneficial fungi and bacteria as a complementary tool to improve plant yield has arisen as a powerful option to meet the current needs to increase productivity and sustainability. However, despite the economic importance of sugarcane, knowledge regarding the microbial community associated with this crop is still limited, as there is still a lack of information on the real diversity and roles of fungal and bacterial species. Current knowledge on sugarcane mycobiota has revealed Epicoccum, Trichoderma, and arbuscular mycorrhizae fungi as the main beneficial fungal agents with high potential for use as microbial-based biostimulants, leading to positive effects that include growth promotion, plant protection, stress resistance, and improved nutrient acquisition. The most studied plant growth-promoting bacteria (PGPB) associated with sugarcane include representatives of the genera Beijerinckia, Gluconacetobacter, Herbaspirillum, Burkholderia, and Azospirillum. The most significant effect obtained from the interaction of sugarcane with these PGPBs is the reduction of chemical nitrogen fertilizers, as these bacteria are able to convert atmospheric nitrogen into an available source, ammonium. Therefore, the use of microbial inoculants should be maximized in crop production, as there is strong evidence that sugarcane plants are able to grow more efficiently by establishing interactions with beneficial microorganisms. This chapter presents an overview on sugarcane production worldwide and gathers the main information about fungi and bacteria described as beneficial to sugarcane, as well as recent data on its complex microbiome

Land-use dynamics in the Mekong delta:From national policy to livelihood sustainability

The Vietnamese Mekong Delta (VMD) is one of the most examined deltas in the world given its dynamics, complexity, and vulnerability. In the past decades, the VMD has changed rapidly, especially the land use in relation with the socioeconomic development. National policy has profoundly influenced these changes and the changes have significantly affected local livelihoods. However, these changes are not well reported systematically. In this study, we investigate land-use changes based on institutional analyses across multiple scales, that is, from national, provincial, to local livelihood based on institutional and sustainability analysis. The results show a strong relationship between legal settings over the last 30 years on land use and livelihood transitions. In addition, the constraints of implementing national legal frameworks at provincial level in practice were identified including effects to local livelihoods. We offer some recommendations for sustainable livelihoods in the VMD, with a focus on increasing socioecological resilience