Mitigating Striga hermonthica parasitism and damage in maize using soybean rotation, nitrogen application, and Striga-resistant varieties in the Nigerian savannas

Open Access article; Published online: 14 Aug 2020Striga hermonthica infestation causes significant losses of maize yield in the Nigerian savannas and several technologies have been developed and promoted to control Striga in maize. However, since no single technology has been found to be effective against Striga, integrated management is needed to achieve satisfactory and sustainable Striga control. Both on-station and on-farm trials were undertaken from 2013 to 2015 in Bauchi and Kano States of Nigeria to evaluate the performance of integrated Striga control technologies. In the on-station trials, a soybean–maize rotation did not suppress Striga in maize in either location. However, nitrogen application suppressed and reduced Striga infection, except in Bauchi in 2014. The soybean–maize rotation accompanied by N application reduced Striga damage in both locations. On farmers’ fields, rotating soybean with maize significantly reduced Striga infection. At the same time, the use of maize varieties with a combined tolerance to drought and resistance to Striga parasitism also increased maize grain yield on farmers’ fields, probably due to three factors: a reduction in Striga infection, reduced effects of a mid-season moisture deficit, and increased uptake of nutrients from the soil. We concluded that the use of Striga-resistant maize varieties in combination with the application of N fertilizer and rotation with soybean could increase the productivity of maize in Striga-infested fields in the Nigerian savannas

Paracrine Diffusion of PrPC and Propagation of Prion Infectivity by Plasma Membrane-Derived Microvesicles

Cellular prion protein (PrPc) is a physiological constituent of eukaryotic cells. The cellular pathways underlying prions spread from the sites of prions infection/peripheral replication to the central nervous system are still not elucidated. Membrane-derived microvesicles (MVs) are submicron (0.1–1 µm) particles, that are released by cells during plasma membrane shedding processes. They are usually liberated from different cell types, mainly upon activation as well as apoptosis, in this case, one of their hallmarks is the exposure of phosphatidylserine in the outer leaflet of the membrane. MVs are also characterized by the presence of adhesion molecules, MHC I molecules, as well as of membrane antigens typical of their cell of origin. Evidence exists that MVs shedding provide vehicles to transfer molecules among cells, and that MVs are important modulators of cell-to-cell communication. In this study we therefore analyzed the potential role of membrane-derived MVs in the mechanism(s) of PrPC diffusion and prion infectivity transmission. We first identified PrPC in association with the lipid raft components Fyn, flotillin-2, GM1 and GM3 in MVs from plasma of healthy human donors. Similar findings were found in MVs from cell culture supernatants of murine neuronal cells. Furthermore we demonstrated that PrPSc is released from infected murine neuronal cells in association with plasma membrane-derived MVs and that PrPSc-bearing MVs are infectious both in vitro and in vivo. The data suggest that MVs may contribute both to the intercellular mechanism(s) of PrPC diffusion and signaling as well as to the process of prion spread and neuroinvasion

Improvement of endocytoscopic findings after per oral endoscopic myotomy (POEM) in esophageal achalasia; does POEM reduce the risk of developing esophageal carcinoma? Per oral endoscopic myotomy, endocytoscopy and carcinogenesis

Background: Per oral endoscopic myotomy (POEM) has been reported to be a new therapeutic option for esophageal achalasia. The possibility that POEM could reduce the risk of developing esophageal squamous cell carcinoma was evaluated.Methods: This was a single-centre, retrospective study. Fifteen consecutive patients with esophageal achalasia who underwent POEM in our institution between August 2010 and January 2012 were enrolled. Ultra-high magnification with endocytoscopy was performed, and both histopathological and immunohistochemical evaluations for Ki-67 and p53 were assessed before and 3 months after POEM.Results: POEM was successfully performed and effectively released the dysphagia symptom in all patients without severe complications. Subjective symptoms (mean Ekcardt score, before 7.4 vs. after 0.5, p<0.05) and manometric pressure studies (mean lower esophageal sphincter pressure), before 82.7 vs. after 22.9 mmHg, p<0.05) showed substantial improvement following POEM. The average numbers of esophageal epithelial nuclei before and after POEM on endocytoscopic images were 128.0 and 78.0, respectively (p<0.05). The mean Ki-67-positive ratio was 26.0 (median 25.4, range, 10.3-33.2) before and 20.7 (median 20.0, 13.1-29.9; p=0.07) after POEM, and the mean p53-positive ratio was 2.35 (median 2.61, 0.32-4.23) before and 0.97 (median 1.49, 0.32-1.56; p<0.05) after POEM. A significant positive correlation was seen between the number of nuclei and the Ki-67-positive ratio (p<0.05).Conclusions: POEM appears to be an effective and less invasive treatment of choice against achalasia and may reduce the risk of esophageal carcinogenesis. Endocytoscopy can be useful for the assessment of esophageal cellular proliferation