Developing the agroecological niche in Nicaragua: The roles of knowledge flows and intermediaries

Supporting transitions to sustainable, resilient agri-food systems is important to ensure stable food supply in the face of growing climate extremes. Agroecology, or diversified farming systems based on ecological principles, can contribute to such systems. Based on a qualitative case study of Nicaragua, a forerunner in agroecology, this paper unpacks an ongoing transition to agroecology, focusing on how the transition has been shaped by knowledge flows and intermediary actors. Using a niche development framework based on knowledge processes, we analyze the growth of the agroecological niche in Nicaragua over three phases of niche development. The findings show how knowledge processes' emphases have shifted over time, as have functions enacted by intermediaries. Dedicated, diversified intermediaries have been key in creating momentum for agroecology, as have individual actors moving between niche and regime. Agency in niche development has come from both niche and regime actors. Finally, we find that Nicaragua's transition to agroecology has been ambiguous: While the niche has succeeded in changing the mainstream selection environment to its favor in some arenas, transition dynamics lag in others. Drawing lessons from this ambiguity, we suggest entry points for broader systems change, such as market stimulation, value chain development, phase-out policies, and supportive policy in related arenas. We also point out possible actions for niche actors such as integration of financial and commercial actors into niches and creation of dedicated market-focused intermediaries. Our results provide evidence of an ongoing transition and action points for supporting niche development in (sustainable agri-food) transitions around the globe.

Multiomics approach to profiling Sertoli cell maturation during development of the spermatogonial stem cell niche

Spermatogonial stem cells (SSCs) are the basis of spermatogenesis, a complex process supported by a specialized microenvironment, called the SSC niche. Postnatal development of SSCs is characterized by distinct metabolic transitions from prepubertal to adult stages. An understanding of the niche factors that regulate these maturational events is critical for the clinical application of SSCs in fertility preservation. To investigate the niche maturation events that take place during SSC maturation, we combined different '-omics' technologies. Serial single cell RNA sequencing analysis revealed changes in the transcriptomes indicative of niche maturation that was initiated at 11 years of age in humans and at 8 weeks of age in pigs, as evident by Monocle analysis of Sertoli cells and peritubular myoid cell (PMC) development in humans and Sertoli cell analysis in pigs. Morphological niche maturation was associated with lipid droplet accumulation, a characteristic that was conserved between species. Lipidomic profiling revealed an increase in triglycerides and a decrease in sphingolipids with Sertoli cell maturation in the pig model. Quantitative (phospho-) proteomics analysis detected the activation of distinct pathways with porcine Sertoli cell maturation. We show here that the main aspects of niche maturation coincide with the morphological maturation of SSCs, which is followed by their metabolic maturation. The main aspects are also conserved between the species and can be predicted by changes in the niche lipidome. Overall, this knowledge is pivotal to establishing cell/tissue-based biomarkers that could gauge stem cell maturation to facilitate laboratory techniques that allow for SSC transplantation for restoration of fertility.