A Duna-Tisza közi talajvíz és a szikes tóvizek hidrogeológiai, hidrodinamikai és hidrokémiai viszonyainak összefüggése a karbonátképződésükkel = Hydrogeology and carbonate mineralization

A dolomit laboratóriumban 100 fok C alatt nem állíthatókelő. A Duna--Tisza közi szikes tavak vizéből, amelyeknek vízhőmérséklete legfeljebb 37 C fokot ér el, dolomit is kiválik. Keletkezésük vízi hátrere részletesen eddig ismeretlen volt. Ezért kilenc helyről több mint három éven át havi vízminták elemzésére került sor. A vizek pH értéke 6,9--9,7, redoxpotenciálja általában 0-- -160, összsó-mennyisége 500--14 000 0mg/l, nátrium-tartalma 0,5--3600 mg/l között változik. A vizek nátriumk-kalcium-magnézium hidrokarbonátosak. Evaporációjukat stabil-izotóp elemzésekkel igazoltuk. Dolomitképződési szempontból fontos magnézium/kalcium arány az evaporációval emelkedik, a CaCO3/Ca arány pedig minden esetben elősegití a dolomitképződést. A dolomit szénradioizotóp elemzések alapján a teljes holocénben képződött. | Dolomite can not be artifically produced in a lab under 100 degrees C. Conversely, in the lakes of the Danube-Tisza Interfluve, in Central Hungary, where water temperatures are not higher than 37 degrees C, dolomite precipitation is and was rather common. The formation of dolomite in these lakes with the underlying reasons unknown so far. To find an answer to a period of 3 consecutive years. The recorded pH of the collected waters was 6.9--9.7,with a redox potential of 0-- -160, a total salt of 500--14 000 mg/l and Na content of 0.5--3500 mg/l. The waters are potassium, calcium, magnesium hydrocarbonate bearing. Their evaporation was justified by stable isotopic studies. In case of doloite formation, the Mg/Ca ratio tends to inrease with the strengthening of evaporation, the yielding CaCO3/Ca ratio promotes dolomite precipitation

Small Extracellular Vesicles Isolated from Serum May Serve as Signal-Enhancers for the Monitoring of CNS Tumors

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Potent Chimeric Antimicrobial Derivatives of the Medicago truncatula NCR247 Symbiotic Peptide

In Rhizobium-legume symbiosis, the bacteria are converted into nitrogen-fixing bacteroids. In many legume species, differentiation of the endosymbiotic bacteria is irreversible, culminating in definitive loss of their cell division ability. This terminal differentiation is mediated by plant peptides produced in the symbiotic cells. In Medicago truncatula more than similar to 700 nodule-specific cysteine-rich (NCR) peptides are involved in this process. We have shown previously that NCR247 and NCR335 have strong antimicrobial activity on various pathogenic bacteria and identified interaction of NCR247 with many bacterial proteins, including FtsZ and several ribosomal proteins, which prevent bacterial cell division and protein synthesis. In this study we designed and synthetized various derivatives of NCR247, including shorter fragments and various chimeric derivatives. The antimicrobial activity of these peptides was tested on the ESKAPE bacteria; Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli as a member of Enterobacteriaceae and in addition Listeria monocytogenes and Salmonella enterica. The 12 amino acid long C-terminal half of NCR247, NCR247C partially retained the antimicrobial activity and preserved the multitarget interactions with partners of NCR247. Nevertheless NCR247C became ineffective on S. aureus, P. aeruginosa, and L. monocytogenes. The chimeric derivatives obtained by fusion of NCR247C with other peptide fragments and particularly with a truncated mastoparan sequence significantly increased bactericidal activity and altered the antimicrobial spectrum. The minimal bactericidal concentration of the most potent derivatives was 1.6 mu M, which is remarkably lower than that of most classical antibiotics. The killing activity of the NCR247-based chimeric peptides was practically instant. Importantly, these peptides had no hemolytic activity or cytotoxicity on human cells. The properties of these NCR derivatives make them promising antimicrobials for clinical use