Etat actuel et evolution de la recherche en economie rurale dans la Republique Federale Allemande

In Germany agricultural economics research has existed since the XVIIIth century. This activity, which was traditionally linked to university, expanded again around 1920, at which time the neo-classical theory was rediscovered. This new school, influenced by the researches achieved in the USA, has proved fertile and has grown richer with the progress of quantitative methods. Current research is focused on agricultural problems of Germany as an EEC member. The changes now occurring in Eastern Europe incite economists to study the agricultural economy and policy of these countries. It is now necessary for them to enlarge their theoretical knowledge by looking for a more international cooperatio

Molecular Mechanisms of T. denticola Induced Tissue Destruction in Human Periodontal Ligament Cells

Periodontal disease (PD) is a complex infection driven by a myriad of bacterial species interacting with host tissues, triggering the release of pro-inflammatory cytokines, chemokines, and tissue-remodeling enzymes like Matrix Metalloproteinases (MMP), culminating in periodontal tissue degradation. Despite clinical intervention, severe periodontitis patients exhibit a persistent pro-inflammatory state, perpetuating tissue destruction. Treponema denticola (T. denticola), an oral anaerobic bacteria, notably abundant in advanced lesions, harbors potent and abundantly expressed virulence factors, including the chymotrypsin-like protease complex (CTLP or dentilisin), implicated in various pathogenic activities like adhesion, ECM degradation, and MMP activation. Our research has shown elevated T. denticola DNA levels correlated with increased MMP2 mRNA expression. Short-term exposure of human periodontal ligament fibroblast cells (hPDL) to wild-type T. denticola bacteria led to prolonged upregulation of the MMP-2-MMP-14-TIMP-2 activation axis for up to 12 days in Vitro. Despite extensive protein-level studies, direct links between T. denticola protease activity and periodontal tissue destruction at transcriptional or epigenetic levels remain scarce. Chemically characterized as a tri-acylated lipoprotein, dentilisin more than likely engages with TLR2-dependent mechanisms. Thus, based on literature and current data from our laboratory, we hypothesize that T. denticola exploits dentilisin to activate a TLR2-dependent pathway, inducing the upregulation of tissue-destructive genes in hPDL cells. This work sheds light on the specific interactions between human periodontal ligament cells and T. denticola, elucidating the transcriptional drivers of periodontal disease chronicity using an array of molecular techniques and high-throughput sequencing methods, revealing potential therapeutic targets beyond antibiotics

Root cap is an important determinant of rhizosphere microbiome assembly

Plants impact the development of their rhizosphere microbial communities. It is yet unclear to what extent the root cap and specific root zones contribute to microbial community assembly. To test the roles of root caps and root hairs in the establishment of microbiomes along maize roots (Zea mays), we compared the composition of prokaryote (archaea and bacteria) and protist (Cercozoa and Endomyxa) microbiomes of intact or decapped primary roots of maize inbred line B73 with its isogenic root hairless (rth3) mutant. In addition, we tracked gene expression along the root axis to identify molecular control points for an active microbiome assembly by roots. Absence of root caps had stronger effects on microbiome composition than the absence of root hairs and affected microbial community composition also at older root zones and at higher trophic levels (protists). Specific bacterial and cercozoan taxa correlated with root genes involved in immune response. Our results indicate a central role of root caps in microbiome assembly with ripple-on effects affecting higher trophic levels and microbiome composition on older root zones

Soil texture is a stronger driver of the maize rhizosphere microbiome and extracellular enzyme activities than soil depth or the presence of root hairs

Aims Different drivers are known to shape rhizosphere microbiome assembly. How soil texture (Texture) and presence or lack of root hairs (Root Hair) of plants affect the rhizosphere microbiome assembly and soil potential extracellular enzyme activities (EEA) at defined rooting depth (Depth) is still a knowledge gap. We investigated effects of these drivers on microbial assembly in rhizosphere and on potential EEA in root-affected soil of maize. Methods Samples were taken from three depths of root hair defective mutant rth3 and wild-type WT maize planted on loam and sand in soil columns after 22 days. Rhizosphere bacterial, archaeal, fungal and cercozoan communities were analysed by sequencing of 16S rRNA gene, ITS and 18S rRNA gene fragments. Soil potential EEA of ss-glucosidase, acid phosphatase and chitinase were estimated using fluorogenic substrates. Results The bacterial, archaeal and cercozoan alpha- and beta-diversities were significantly and strongly altered by Texture, followed by Depth and Root Hair. Texture and Depth had a small impact on fungal assembly, and only fungal beta-diversity was significantly affected. Significant impacts by Depth and Root Hair on beta-diversity and relative abundances at taxonomic levels of bacteria, archaea, fungi and cercozoa were dependent on Texture. Likewise, the patterns of potential EEA followed the trends of microbial communities, and the potential EEA correlated with the relative abundances of several taxa. Conclusions Texture was the strongest driver of rhizosphere microbiome and of soil potential EEA, followed by Depth and Root Hair, similarly to findings in maize root architecture and plant gene expression studies

Soil texture is a stronger driver of the maize rhizosphere microbiome and extracellular enzyme activities than soil depth or the presence of root hairs

Aims: Different drivers are known to shape rhizosphere microbiome assembly. How soil texture (Texture) and presence or lack of root hairs (Root Hair) of plants affect the rhizosphere microbiome assembly and soil potential extracellular enzyme activities (EEA) at defined rooting depth (Depth) is still a knowledge gap. We investigated effects of these drivers on microbial assembly in rhizosphere and on potential EEA in root-affected soil of maize. Methods: Samples were taken from three depths of root hair defective mutant rth3 and wild-type WT maize planted on loam and sand in soil columns after 22 days. Rhizosphere bacterial, archaeal, fungal and cercozoan communities were analysed by sequencing of 16S rRNA gene, ITS and 18S rRNA gene fragments. Soil potential EEA of ß-glucosidase, acid phosphatase and chitinase were estimated using fluorogenic substrates. Results: The bacterial, archaeal and cercozoan alpha- and beta-diversities were significantly and strongly altered by Texture, followed by Depth and Root Hair. Texture and Depth had a small impact on fungal assembly, and only fungal beta-diversity was significantly affected. Significant impacts by Depth and Root Hair on beta-diversity and relative abundances at taxonomic levels of bacteria, archaea, fungi and cercozoa were dependent on Texture. Likewise, the patterns of potential EEA followed the trends of microbial communities, and the potential EEA correlated with the relative abundances of several taxa. Conclusions: Texture was the strongest driver of rhizosphere microbiome and of soil potential EEA, followed by Depth and Root Hair, similarly to findings in maize root architecture and plant gene expression studies

The Effects of Oral Consumption of Selenium Nanoparticles on Chemotactic and Respiratory Burst Activities of Neutrophils in Comparison with Sodium Selenite in Sheep

The present study was designed to compare the effects of nano-selenium and of sodium selenite on the chemotactic and respiratory burst activities of neutrophils in sheep. Fifteen sheep were randomly divided into three groups. Groups 1 and 2 received selenium nanoparticles (1 mg/kg) or sodium selenite (1 mg/kg) orally, respectively, for ten consecutive days, and the third group was considered as the control. To determine the chemotactic and respiratory burst activities of the neutrophils, the leading front assay and the NBT test were used on heparinized blood samples that were collected at different intervals (days 0, 10th, 20th, and 30th). The results obtained showed that the chemotactic activities in groups 1 and 2 increased significantly on the 10th, 20th, and 30th day, compared to day 0, and on the 20th day in comparison with the 10th day, while in group 2, there was a significant decrease on the 30th day compared to the 20th day. The chemotactic activities in group 1 were significantly higher than in group 2 on the 10th day and in the control group on the 10th, 20th, and 30th day, but the chemotactic activities in group 2 were significantly higher than those in the control group only on the 20th day. On the 30th day into the experiment, the respiratory bursts in groups 1 and 2 were significantly stronger in comparison with those at day 0. Overall, nano-selenium increased the chemotactic and respiratory burst activities more significantly than sodium selenite, which is suggestive of a stronger stimulatory effect of the Se nanoparticles on intracellular activities