A methodological approach to upscale toward an agroecology system in EU-LAFSs: The case of the parma bio-district

The increasing interest in bio-districts is part of the debate on the capacity to integrate agri-food systems and territory in order to improve the quality of life in rural communities. Considering the goals of developing and promoting an innovative territorial rural development approach, the bio-district can become a process toward a more sustainable model represented by the agroecological agriculture system. The paper presents a case study of the Parma bio-district through the approach of a Localized Agri Food System (LAFS) to verify whether bio-districts can be a tool for scaling up towards agroecology. Stakeholder classification and analysis are conducted using an influence-interest matrix. We identified four groups of stakeholders in relation to their interests and power to influence the process. In the case of the Parma bio-district the role of local institutions in dialogue with consumers and producers' associations is crucial for success. We conclude that bio-districts can be a tool for a scaling-up towards agroecology since they can facilitate a synergetic relation between organic and agroecological agriculture, spreading organic agriculture more widely around the local area. However, the involvement of a wide variety of different stakeholders means that governance is a key element in facilitating "cross fertilization" and preventing the process from becoming purely formulaic

A Methodological Approach to Upscale Toward an Agroecology System in EU-LAFSs: The Case of the Parma Bio-District

The increasing interest in bio-districts is part of the debate on the capacity to integrate agri-food systems and territory in order to improve the quality of life in rural communities. Considering the goals of developing and promoting an innovative territorial rural development approach, the bio-district can become a process toward a more sustainable model represented by the agroecological agriculture system. The paper presents a case study of the Parma bio-district through the approach of a Localized Agri Food System (LAFS) to verify whether bio-districts can be a tool for scaling up towards agroecology. Stakeholder classification and analysis are conducted using an influence–interest matrix. We identified four groups of stakeholders in relation to their interests and power to influence the process. In the case of the Parma bio-district the role of local institutions in dialogue with consumers and producers’ associations is crucial for success. We conclude that bio-districts can be a tool for a scaling-up towards agroecology since they can facilitate a synergetic relation between organic and agroecological agriculture, spreading organic agriculture more widely around the local area. However, the involvement of a wide variety of dierent stakeholders means that governance is a key element in facilitating “cross fertilization” and preventing the process from becoming purely formulaic

A High Incidence of Meiotic Silencing of Unsynapsed Chromatin Is Not Associated with Substantial Pachytene Loss in Heterozygous Male Mice Carrying Multiple Simple Robertsonian Translocations

Meiosis is a complex type of cell division that involves homologous chromosome pairing, synapsis, recombination, and segregation. When any of these processes is altered, cellular checkpoints arrest meiosis progression and induce cell elimination. Meiotic impairment is particularly frequent in organisms bearing chromosomal translocations. When chromosomal translocations appear in heterozygosis, the chromosomes involved may not correctly complete synapsis, recombination, and/or segregation, thus promoting the activation of checkpoints that lead to the death of the meiocytes. In mammals and other organisms, the unsynapsed chromosomal regions are subject to a process called meiotic silencing of unsynapsed chromatin (MSUC). Different degrees of asynapsis could contribute to disturb the normal loading of MSUC proteins, interfering with autosome and sex chromosome gene expression and triggering a massive pachytene cell death. We report that in mice that are heterozygous for eight multiple simple Robertsonian translocations, most pachytene spermatocytes bear trivalents with unsynapsed regions that incorporate, in a stage-dependent manner, proteins involved in MSUC (e.g., γH2AX, ATR, ubiquitinated-H2A, SUMO-1, and XMR). These spermatocytes have a correct MSUC response and are not eliminated during pachytene and most of them proceed into diplotene. However, we found a high incidence of apoptotic spermatocytes at the metaphase stage. These results suggest that in Robertsonian heterozygous mice synapsis defects on most pachytene cells do not trigger a prophase-I checkpoint. Instead, meiotic impairment seems to mainly rely on the action of a checkpoint acting at the metaphase stage. We propose that a low stringency of the pachytene checkpoint could help to increase the chances that spermatocytes with synaptic defects will complete meiotic divisions and differentiate into viable gametes. This scenario, despite a reduction of fertility, allows the spreading of Robertsonian translocations, explaining the multitude of natural Robertsonian populations described in the mouse

Genetically enhanced asynapsis of autosomal chromatin promotes transcriptional dysregulation and meiotic failure

During meiosis, pairing of homologous chromosomes and their synapsis are essential prerequisites for normal male gametogenesis. Even limited autosomal asynapsis often leads to spermatogenic impairment, the mechanism of which is not fully understood. The present study was aimed at deliberately increasing the size of partial autosomal asynapsis and analysis of its impact on male meiosis. For this purpose, we studied the effect of t12 haplotype encompassing four inversions on chromosome 17 on mouse autosomal translocation T(16;17)43H (abbreviated T43H). The T43H/T43H homozygotes were fully fertile in both sexes, while +/T43H heterozygous males, but not females, were sterile with meiotic arrest at late pachynema. Inclusion of the t12 haplotype in trans to the T43H translocation resulted in enhanced asynapsis of the translocated autosome, ectopic phosphorylation of histone H2AX, persistence of RAD51 foci, and increased gene silencing around the translocation break. Increase was also on colocalization of unsynapsed chromatin with sex body. Remarkably, we found that transcriptional silencing of the unsynapsed autosomal chromatin precedes silencing of sex chromosomes. Based on the present knowledge, we conclude that interference of meiotic silencing of unsynapsed autosomes with meiotic sex chromosome inactivation is the most likely cause of asynapsis-related male sterility

Human male meiotic sex chromosome inactivation.

Contains fulltext : 108163.pdf (publisher's version ) (Open Access)In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly phosphorylated at S139 of H2AX leading to the repression of gonosomal genes, a process known as meiotic sex chromosome inactivation (MSCI), which has been studied best in mice. Post-meiotically this repression is largely maintained. Disturbance of MSCI in mice leads to harmful X,Y gene expression, eventuating in spermatocyte death and sperm heterogeneity. Sperm heterogeneity is a characteristic of the human male. For this reason we were interested in the efficiency of MSCI in human primary spermatocytes. We investigated MSCI in pachytene spermatocytes of seven probands: four infertile men and three fertile controls, using direct and indirect in situ methods. A considerable degree of variation in the degree of MSCI was detected, both between and within probands. Moreover, in post-meiotic stages this variation was observed as well, indicating survival of spermatocytes with incompletely inactivated sex chromosomes. Furthermore, we investigated the presence of H3K9me3 posttranslational modifications on the X and Y chromatin. Contrary to constitutive centromeric heterochromatin, this heterochromatin marker did not specifically accumulate on the XY body, with the exception of the heterochromatic part of the Y chromosome. This may reflect the lower degree of MSCI in man compared to mouse. These results point at relaxation of MSCI, which can be explained by genetic changes in sex chromosome composition during evolution and candidates as a mechanism behind human sperm heterogeneity