The influence of chorionic gonadotropin and estriol on NK cell phenotype and functional activity

The influence of chorionic gonadotropin (CG) and estriol (Е₃) at the concentrations typical of pregnancy on the expression of phenotypic markers and cytokine production by separated NK cells has been studied. It has been found that these hormones increase the percentage of CD56^bright L-selectin⁺ NK cells, but also stimulate the expression of the inhibitory molecule NKG2A in the lymphocytes. In addition, Е₃ and CG stimulate the production of TGF-β, inhibiting the secretion of all other cytokines by separated NK cells. In general, these hormones contribute to the formation of the phenotype and cytokine spectrum characteristic of the regulatory NK3 subpopulation of NK cells during pregnancy.     

The absence or presence of a lytic coliphage affects the response of <Emphasis Type="Italic">Escherichia coli</Emphasis> to heat,chlorine, or UV exposure

Disinfection aims at maximal inactivation of target organisms and the sustainable suppression of their regrowth. Whereas many disinfection efforts achieve efficient inactivation when the effect is measured directly after treatment, there are questions about the sustainability of this effect. One aspect is that the treated bacteria might recover and regain the ability to grow. In an environmental context, another question is how amenable surviving bacteria are to predation by omnipresent bacteriophages. Provisional data suggested that bacteria when subjected to sublethal heat stress might develop a phage-resistant phenotype. The result made us wonder about the susceptibility to phage-mediated lysis for bacteria exposed to a gradient of chlorine and UV-LED disinfection strengths. Whereas bacteria exposed to low sublethal chlorine doses still underwent phage-mediated lysis, the critical chlorine Ct of 0.5 mg min/L eliminated this susceptibility and induced phage resistance in the cells that survived treatment. In the case of UV, even the smallest tested dose of 2.8 mJ/cm² abolished phage lysis leading to direct regrowth. Results suggest that bacteria surviving disinfection might have higher environmental survival chances directly after treatment compared to non-treated cells. A reason could possibly lie in their compromised metabolism that is essential for phage replication.