The transcriptional regulation of the horizontally acquired iron uptake system, yersiniabactin and its contribution to oxidative stress tolerance and pathogenicity of globally emerging strains.

The bacterial species () is a highly diverse pathogen containing more than 2600 distinct serovars, which can infect a wide range of animal and human hosts. Recent global emergence of multidrug resistant strains, from serovars Infantis and Muenchen is associated with acquisition of the epidemic megaplasmid, pESI that augments antimicrobial resistance and pathogenicity. One of the main pESI's virulence factors is the potent iron uptake system, yersiniabactin encoded by , and gene cluster.

Persistent Salmonella infections in humans are associated with mutations in the BarA/SirA regulatory pathway.

Several bacterial pathogens, including Salmonella enterica, can cause persistent infections in humans by mechanisms that are poorly understood. By comparing genomes of isolates longitudinally collected from 256 prolonged salmonellosis patients, we identified repeated mutations in global regulators, including the barA/sirA two-component regulatory system, across multiple patients and Salmonella serovars. Comparative RNA-seq analysis revealed that distinct mutations in barA/sirA led to diminished expression of Salmonella pathogenicity islands 1 and 4 genes, which are required for Salmonella invasion and enteritis.

Alleviation of Severe Skin Insults Following High-Dose Irradiation with Isolated Human Fetal Placental Stromal Cells.

Skin exposure to high-dose irradiation, as commonly practiced in radiotherapy, affects the different skin layers, causing dry and wet desquamation, hyperkeratosis fibrosis, hard to heal wounds and alopecia and damaged hair follicles. Fetal tissue mesenchymal stromal cells (f-hPSC) were isolated from excised human fetal placental tissue, based on their direct migration from the tissue samples to the tissue dish. The current study follows earlier reports on for the mitigation of acute radiation syndrome following whole body high-dose exposure with remotely injected f-hPSC.

The ancestral stringent response potentiator, DksA has been adapted throughout evolution to orchestrate the expression of metabolic, motility, and virulence pathways.

DksA is a conserved RNA polymerase-binding protein known to play a key role in the stringent response of proteobacteria species, including many gastrointestinal pathogens. Here, we used RNA-sequencing of and serovar Typhimurium, together with phenotypic comparison to study changes in the DksA regulon, during evolution. Comparative RNA-sequencing showed that under non-starved conditions, DksA controls the expression of 25%, 15%, and 20% of the , and genes, respectively, indicating that DksA is a pleiotropic regulator, expanding its role beyond the canonical stringent response.

Alleviation of acute radiation-induced bone marrow failure in mice with human fetal placental stromal cell therapy.

Purpose: Selected placental mesenchymal stromal cells isolated from the fetal mesenchymal placental tissues (f-hPSCs) were tested as cell therapy of lethal acute radiation syndrome (ARS) with bone marrow regeneration and induced extramedullary hematopoiesis.

Methods And Materials: f-hPSCs were isolated from the chorionic plate of human placentae and further expanded in regular culture conditions. 2 × 10 f-hPSCs were injected on days 1 and 4 to 8-Gy total body irradiated (TBI) C3H mice, both intramuscularly and subcutaneously.

Isolation and expansion of high yield of pure mesenchymal stromal cells from fresh and cryopreserved placental tissues.

The injection of placental stromal cells isolated from fetal human tissues (f-hPSC) was reported to indirectly induce tissue regeneration in different animal models. A procedure of f-hPSC isolation from fragments of both selected fresh or cryopreserved bulk placental neonate tissues is proposed, based on their high migratory potential,. The fragments of the desired fetal placental tissues are adhered to a culture dish by traces of diluted fibrin and covered with culture medium.