Paratransgenesis to control malaria vectors: a semi-field pilot study

BACKGROUND: Malaria still remains a serious health burden in developing countries, causing more than 1 million deaths annually. Given the lack of an effective vaccine against its major etiological agent, Plasmodium falciparum, and the growing resistance of this parasite to the currently available drugs repertoire and of Anopheles mosquitoes to insecticides, the development of innovative control measures is an imperative to reduce malaria transmission. Paratransgenesis, the modification of symbiotic organisms to deliver anti-pathogen effector molecules, represents a novel strategy against Plasmodium development in mosquito vectors, showing the potential to reduce parasite development. However, the field application of laboratory-based evidence of paratransgenesis imposes the use of more realistic confined semi-field environments. METHODS: Large cages were used to evaluate the ability of bacteria of the genus Asaia expressing green fluorescent protein (Asaia (gfp)), to diffuse in Anopheles stephensi and Anopheles gambiae target mosquito populations. Asaia (gfp) was introduced in large cages through the release of paratransgenic males or by sugar feeding stations. Recombinant bacteria transmission was directly detected by fluorescent microscopy, and further assessed by molecular analysis. RESULTS: Here we show the first known trial in semi-field condition on paratransgenic anophelines. Modified bacteria were able to spread at high rate in different populations of An. stephensi and An. gambiae, dominant malaria vectors, exploring horizontal ways and successfully colonising mosquito midguts. Moreover, in An. gambiae, vertical and trans-stadial diffusion mechanisms were demonstrated. CONCLUSIONS: Our results demonstrate the considerable ability of modified Asaia to colonise different populations of malaria vectors, including pecies where its association is not primary, in large environments. The data support the potential to employ transgenic Asaia as a tool for malaria control, disclosing promising perspective for its field application with suitable effector molecules

Salmonella enterica serovar typhimurium exploits inflammation to modify swine intestinal microbiota

Salmonella enterica serovar Typhimurium is an important zoonotic gastrointestinal pathogen responsible for foodborne disease worldwide. It is a successful enteric pathogen because it has developed virulence strategies allowing it to survive in a highly inflamed intestinal environment exploiting inflammation to overcome colonization resistance provided by intestinal microbiota. In this study, we used piglets featuring an intact microbiota, which naturally develop gastroenteritis, as model for salmonellosis. We compared the effects on the intestinal microbiota induced by a wild type and an attenuated S. Typhimurium in order to evaluate whether the modifications are correlated with the virulence of the strain. This study showed that Salmonella alters microbiota in a virulence-dependent manner. We found that the wild type S. Typhimurium induced inflammation and a reduction of specific protecting microbiota species (SCFA-producing bacteria) normally involved in providing a barrier against pathogens. Both these effects could contribute to impair colonization resistance, increasing the host susceptibility to wild type S. Typhimurium colonization. In contrast, the attenuated S. Typhimurium, which is characterized by a reduced ability to colonize the intestine, and by a very mild inflammatory response, was unable to successfully sustain competition with the microbiota

Raman spectroscopy uncovers biochemical tissue-related features of extracellular vesicles from mesenchymal stromal cells

Extracellular vesicles (EVs) from mesenchymal stromal cells (MSC) are emerging as valuable therapeutic agents for tissue regeneration and immunomodulation, but their clinical applications have so far been limited by the technical restraints of current isolation and characterisation procedures. This study shows for the first time the successful application of Raman spectroscopy as label-free, sensitive and reproducible means of carrying out the routine bulk characterisation of MSC-derived vesicles before their use in vitro or in vivo, thus promoting the translation of EV research to clinical practice. The Raman spectra of the EVs of bone marrow and adipose tissue-derived MSCs were compared with human dermal fibroblast EVs in order to demonstrate the ability of the method to distinguish the vesicles of the three cytotypes automatically with an accuracy of 93.7%. Our data attribute a Raman fingerprint to EVs from undifferentiated and differentiated cells of diverse tissue origin, and provide insights into the biochemical characteristics of EVs from different sources and into the differential contribution of sphingomyelin, gangliosides and phosphatidilcholine to the Raman spectra themselves

Superoxide anion release by polymorphonuclear leucocytes in whole blood of newborns and mothers during the perinatal period

Superoxide anion (.O2-) production was investigated in whole blood of mothers in the peripartal period and in neonates. Blood samples from 14 mothers undergoing vaginal delivery (VD) were tested at the beginning of labor, during labor, after delivery, and 4 d after delivery. Nine mothers undergoing elective cesarean section (ECS) were tested before anesthesia, after extraction of the fetus, and 4 d later. Seventy-two healthy, full-term newborn infants were examined at birth and on the fourth day of life. Red cell glutathione peroxidase, catalase, glutathione reductase, and superoxide dismutase activities were also measured at birth and on the fourth day of life in 26 of the 72 neonates. Higher .O2- levels were detected in mothers undergoing VD compared with ECS (p < 0.05). A significant decrease was detected in zymosan-stimulated .O2- production between cord and fourth-day blood samples in both VD- and ECS-delivered infants (p < 0.01). Zymosan-stimulated samples showed higher values after VD than ECS, both in cord blood (p < 0.004) and on the fourth day of life (p < 0.006). A positive correlation was found between .O2- release in zymosan-stimulated cord blood and that found in the mothers at the beginning of labor (r = 0.654; p < 0.01), during labor (r = 0.721; p = 0.008), and after delivery (r = 0.832; p = 0.0008). A positive correlation was also found between .O2- release and glutathione peroxidase on the fourth day (r = 0.709, p = 0.014)