Direct detection of Salmonella spp. in estuaries by using a DNA probe

A method for direct detection of Salmonella spp. in water was developed by using a commercially available DNA probe. Particulate DNA was extracted from 500- to 1,500-ml water samples collected from New York Harbor and Chesapeake Bay and used as a substrate for a salmonella-specific DNA probe in dot blot assays. The method detected salmonellae in water samples from 12 of 16 sites, including 6 sites where salmonellae could not be cultured. The specificity of the probe was evaluated, and cross-hybridization, although negligible, was used to set detection limits for the assay. Salmonella DNA bound the probe quantitatively, and from these results Salmonella DNA in the total particulate DNA in environmental samples could be estimated. The data obtained in this study indicate that Salmonella spp. often are not detected in water samples by culture methods, even when they are present in significant numbers.     

Coccidian assemblages in the Wyoming ground squirrel, Spermophilus elegans elegans.

One thousand nineteen Wyoming ground squirrels (Spermophilus elegans elegans) from 4 populations in southern Wyoming were examined for intestinal parasites. The most prevalent parasites were 6 species of coccidia: Eimeria beecheyi, Eimeria bilamellata, Eimeria callospermophili, Eimeria larimerensis, Eimeria morainensis, and Eimeria spermophili. Most ground squirrels harbored 2 or more species. This eimerian assemblage was present across populations and over years. Differences in the prevalence of infection were not found among host age classes or between sexes. The presence or absence of helminths was independent of the presence and absence of Eimeria. A log-linear model to test the independence of the distribution of Eimeria spp. among hosts revealed 3 significant positive associations, for E. bilamellata and E. beecheyi, E. morainesis and E. callospermophili, and E. larimerensis and E. bilamellata.     

Hepatoprotective activity of betulonic acid amides containing piperidine or pyrrolidine nitroxide moieties

Betulonic acid amides containing the nitroxyl radical moiety exert an anticholestatic effect in mice. The introduction of piperidine nitroxide moiety into the lupane core increases its hepatoprotective activity. Oral administration of the piperidine nitroxide derivative in a dose of 50 mg/kg does not stimulate transplanted tumor growth and increases lifespan in mice.     

Genotoxic activity of 1,2,3‐triazolyl modified furocoumarins and 2,3‐dihydrofurocoumarins

The furocoumarin backbone is a promising platform for chemical modifications aimed at creating new pharmaceutical agents. However, the high level of biological activity of furocoumarins is associated with a number of negative effects. For example, some of the naturally occurring ones and their derivatives can show genotoxic and mutagenic properties as a result of their forming crosslinks with DNA molecules. Therefore, a particularly important area for the chemical modification of natural furocoumarins is to reduce the negative aspects of their bioactivity. By studying a group of 21 compounds—1,2,3‐triazolyl modified derivatives of furocoumarin and peucedanin—using the SOS chromotest, the Ames test, and DNA‐comet assays, we revealed modifications that can neutralize the structure's genotoxic properties. Theoretical aspects of the interaction of the compound library were studied using molecular modeling and this identified the leading role of the polyaromatic molecular core that takes part in stacking‐interactions with the pi‐systems of the nitrogenous bases of DNA.     

Trophoblast–endothelium signaling involves angiogenesis and apoptosis in a dynamic bioprinted placenta model

Trophoblast invasion and remodeling of the maternal spiral arteries are required for pregnancy success. Aberrant endothelium–trophoblast crosstalk may lead to preeclampsia, a pregnancy complication that has serious effects on both the mother and the baby. However, our understanding of the mechanisms involved in this pathology remains elementary because the current in vitro models cannot describe trophoblast–endothelium interactions under dynamic culture. In this study, we developed a dynamic three-dimensional (3D) placenta model by bioprinting trophoblasts and an endothelialized lumen in a perfusion bioreactor. We found the 3D printed perfusion bioreactor system significantly augmented responses of endothelial cells by encouraging network formations and expressions of angiogenic markers, cluster of differentiation 31 (CD31), matrix metalloproteinase-2 (MMP2), matrix metalloproteinase-9 (MMP9), and vascular endothelial growth factor A (VEGFA). Bioprinting favored colocalization of trophoblasts with endothelial cells, similar to in vivo observations. Additional analysis revealed that trophoblasts reduced the angiogenic responses by reducing network formation and motility rates while inducing apoptosis of endothelial cells. Moreover, the presence of endothelial cells appeared to inhibit trophoblast invasion rates. These results clearly demonstrated the utility and potential of bioprinting and perfusion bioreactor system to model trophoblast–endothelium interactions in vitro. Our bioprinted placenta model represents a crucial step to develop advanced research approach that will expand our understanding and treatment options of preeclampsia and other pregnancy-related pathologies.     

Chemical approaches for investigating phosphorylation in signal transduction networks

The power and scope of chemical synthesis offer considerable opportunities to broaden the lexicon of chemical tools that can be implemented for the study of complex biological systems. To investigate individual signaling proteins and pathways, chemical tools provide a powerful complement to existing genetic, chemical genetic and immunologic methods. In particular, understanding phosphorylation-mediated signaling in real time yields important information about the regulation of cellular function and insights into the origin of disease. Recent advances in the development of photolabile caged analogs of bioactive species and fluorescence-based sensors of protein kinase activities are useful for investigating protein phosphorylation and the roles of phosphoproteins. Photolabile caged analogs allow spatial and temporal control over the release of a compound, while fluorescence-based sensors allow the real-time visualization of kinase activity. Here, we discuss recent advances that have increased the specificity and availability of these tools.