Bacteria spatial tracking in Urban Park soils with MALDI-TOF Mass Spectrometry and Specific PCR.

Urban parks constitute one of the main leisure areas, especially for the most vulnerable people in our society, children, and the elderly. Contact with soils can pose a health risk. Microbiological testing is a key aspect in determining whether they are suitable for public use. The aim of this work is to map the spatial distribution of potential dangerous Enterobacteria but also bioremediation useful (lipase producers) isolates from soils in an urban park in the area of Valencia (Spain). To this end, our team has collected 25 samples of soil and isolated 500 microorganisms, using a mobile application to collect information of the soil samples (i.e. soil features, temperature, humidity, etc.) with geolocation. A combined protocol including matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and 16S rDNA sequencing PCR has been established to characterize the isolates. The results have been processed using spatial statistical techniques (using Kriging method), taking into account the number of isolated strains, also proving the reactivity against standard pathogenic bacterial strains (Escherichia coli, Bacillus cereus, Salmonella, Pseudomonas and Staphylococcus aureus), and have increased the number of samples (to 896 samples) by interpolating spatially each parameter with this statistical method. The combined use of methods from biology and computer science allows the quality of the soil in urban parks to be predicted in an agile way, which can generate confidence in its use by citizens.

Microwave induced shift of the main phase transition in phosphatidylcholine membranes.

Numerous experimental evidence show that exposure of biological systems to extremely high frequency microwaves may induce significant effects even at low powers. These effects are thought to occur via nonthermal mechanisms involving primarily the interaction of microwaves with phospholipid membrane structures. However, no conclusive experimental evidence that biomembranes exhibit remarkable sensitivity to this radiation has been provided up to now. Here, deuterium nuclear magnetic resonance spectroscopy is used to study the effects of microwaves on 1,2-Dimyristoyl-sn-glycero-3-phosphatidylcholine/(2)H(2)O multilamellar vesicles that serve as biomimetic membranes. Here we show that, if the membrane is brought into close proximity to the transition point, microwaves induce a reduction of water ordering at the membrane interface, an upward shift of the main phase transition temperature and a broadening of the transition region. A deep dosimetric analysis shows that the above effects are nonthermal, indicating the need for a nonthermal hypothesis to explain them. This study suggests that exposure to high-frequency microwaves can have far reaching consequences on active biological systems.

E, Z and positional-monoenoic phyto-fatty acids influencing membrane fluidity: DSC and NMR experiments.

The membrane fluidity of biological tissues is highly influenced by the π-bond position and isomeric configuration in the long chain of phyto-fatty acids (FAs). Z, E and positional isomeric monoenoic lipids, i.e. the phytomolecules oleic (OA), elaidic (EA), vaccenic acid (TV) and its Z-isomer (CV), have been evaluated for their effects on the fluidity of cellular membranes. To this purpose the Differential Scanning Calorimetry (DSC) and Deuterium Nuclear Magnetic Resonance ((2)H-NMR), are suitable techniques to understand the supramolecular lamellar structure during the order (gel)-disorder (fluid) transition. It was found that the presence of CV concentration, induces the biomimetic system to reach the first step to fluid phase earlier than the membrane containing OA. DSC showed that the endothermic peak onset of the membrane containing CV occurs at a lower temperature than that of a membrane containing an equal amount of OA. (2)H-NMR investigation confirmed the last statement. In fact the study of the main phase transition of the two different systems, revealed that model membrane containing a 3% (w/w) of CV goes in ripple phase, i.e. the first step to the fluid state, at a lower temperature as compared to the membrane of an identical system with OA.

Frequency and irradiation time-dependant antiproliferative effect of low-power millimeter waves on RPMI 7932 human melanoma cell line.

The biological effects produced by low power millimeter waves (MMW) were studied on the RPMI 7932 human melanoma cell line. Three different frequency-type irradiation modes were used: the 53.57-78.33 GHz wide-band frequency range, the 51.05 GHz and the 65.00 GHz monochromatic frequencies. In all three irradiation conditions, the radiation energy was low enough not to increase the temperature of the cellular samples. Three hours of radiation treatment, applied every day to the melanoma cell samples, were performed at each frequency exposure condition. The wide-band irradiation treatment effectively inhibited cell growth, while both the monochromatic irradiation treatments did not affect the growth trend of RPMI 7932 cells. A light microscopy analysis revealed that the low-intensity wide-band millimeter radiation induced significant morphological alterations on these cells. Furthermore, a histochemical study revealed the low proliferative state of the irradiated cells. This work provides further evidence of the antiproliferative effects on tumor cells induced by low power MMW in the 50-80 GHz frequency range of the electromagnetic spectrum.