Flow cytometric detection of oxidative DNA damage in fish spermatozoa exposed to cadmium — Short communication

The aim of the present pilot study was to apply a flow cytometric assay, the so-called OxyDNA test, to determine the level of oxidative DNA damage in fish spermatozoa exposed to different concentrations (0.01–10,000 mg/L) of cadmium. Milt was collected from three randomly selected Prussian carp (Carassius auratus gibelio) males. Oxidative DNA damage was assessed with the OxyDNA kit and using flow cytometry. The ratio of OxyDNA-positive events increased significantly at higher cadmium concentrations. The results indicate that direct contact of fish spermatozoa with cadmium-polluted water initiates genotoxic damage

Effects of high ambient temperature on fish sperm plasma membrane integrity and mitochondrial activity — A flow cytometric study

Local extreme climatic conditions occurring as a result of global climate change may interfere with the reproduction of animals. In the present study fish spermatozoa were incubated at different temperatures (20, 25, 30 and 40 °C) for 10 and 30 minutes, respectively and plasma membrane integrity and mitochondrial membrane potential changes were evaluated with flow cytometry using SYBR-14/PI and Mitotracker Deep Red FM fluorescent dyes. No significant differences were found in plasma membrane integrity at either incubation temperatures or time points. Mitotracker Deep Red FM histogram profiles indicating mitochondrial activity showed significant (p < 0.001) alterations in all cases of higher (25, 30 and 40 °C) temperature treatments as compared to the samples incubated at 20 °C. Our results indicate that fish spermatozoa exposed to high temperatures suffer sublethal damage that cannot be detected with conventional, vital staining techniques

Kinetics and Structure of Self-Assembled Flagellin Monolayers on Hydrophobic Surfaces in the Presence of Hofmeister Salts: Experimental Measurement of the Protein Interfacial Tension at the Nanometer Scale

In the present study, we monitor the adsorption–desorption kinetics and adsorbed layer structure of the bacterial protein flagellin in the presence of Hofmeister salts by a surface sensitive label-free optical biosensor (optical waveguide lightmode spectroscopy, OWLS). The recorded OWLS data were analyzed by a computer code using a set of coupled differential equations modeling the adsorption–desorption process. By supposing reversibly and irreversibly adsorbed protein states with different adsorption footprints, the kinetic data could be perfectly fitted. We revealed that the proteins adsorbing in the presence of kosmotropic salts had smaller footprints, leading to a more oriented and densely packed layer. Kosmotropic salts increased both the adsorption rate constant and the transition rate constants from the reversibly to the irreversibly adsorbed state. In contrast, chaotropic salts increased the desorption rate constant and led to decreased adsorbed mass and a more loosely packed film. Neither circular dichroism spectroscopy in bulk solutions or Fourier transform infrared spectroscopy of surface-adsorbed flagellins could reveal significant structural changes due to the presence of the Hofmeister salts, and supported our conclusions about the adsorption mechanism. On the basis of the measured kinetic and structural data (footprints of adsorbed proteins), we developed a model to calculate the protein–water-substrate interfacial tension in the presence of Hofmeister salts, and compared the experimentally obtained values with related literature data. The calculated values are consistent with previously published data of surface tension changes, andto the best of our knowledgerepresent the first experimental results for this quantity

Fényemittáló és nagyspinű polimerek előállítása és vizsgálata = Synthesis and characterization of light emitting and high-spin polymers

Glükozilezett naftalén-fenilén típusú kopolimert állítottunk elő Suzuki-polikondenzációval. A kopolimer kék fényt emittált és önszerveződő tulajdonságokat mutatott mind oldat, mind szilárd fázisban. Kék fényt emittáló egyforma méretű nanogömbök képződését figyeltük meg. Potenciálisan nagyspinű, trifenilamin tartalmú poli(para-fenilén) kopolimer szintézisét valósítottuk meg. Vizsgáltuk a polikondenzációs reakció körülményeinek hatását a képződő polimerek szerkezetére és molekulatömegére. Tanulmányoztuk a kopolimer optikai tulajdonságait. Kék fény emisszióját tapasztaltuk. Az emissziós maximum az oldószer polaritásának hatására eltolható volt. Mono- és bifenantrolin-funkcionalizált polietilén glikolt és poliizobutilént készítettünk és vizsgáltuk vas(II)-ionnal szembeni viselkedésüket. A vas(II)-fenantrolin komplexeket tömegspektrometriás módszerrel karakterizáltuk. Vastartalmú, jól definiált ionomer jellegű hálózatokat állítottunk elő. A hálózatok jó modellként szolgálhatnak a magnetit nanopor felületi módosításához. Az apoláros szerkezetű konjugált polimerek tömegspektrometriás vizsgálatához klorid-ion kapcsolásos módszerrel kiegészített atmoszférikus nyomású fotoionizációs (APPI) módszert fejlesztettünk ki. A továbbfejlesztett módszer segítségével lehetőség nyílt különböző végcsoportú poliizobutilének végcsoportjainak, valamint bifunkciós polimer esetén a karok számának meghatározására, fragmentáció nélküli, lágyionizációs technikával. | A glycosylated polynaphthalene-phenylene type copolymer was prepared by Suzuki copolymerization. The copolymer showed blue-light emission and self-assembly in both solution and in solid phase. The formation of blue-light emitting, uniform size nanospheres could be observed. Synthesis of a potential high-spin poly(para-phenylene) copolymer containing triphenylamine was attained. The effect of the polycondensation parameters on the structure and molecular weight of the polymers formed was studied. Optical properties of the copolymer have been investigated. It showed blue-light emission. Emission maximum could be shifted by using solvent with different polarity. Mono- and biphenantroline-functionalized poly(ethylene-glycol) and poly(isobutylene) have been prepared and their behaviour was investigated in the presence of iron(II)-ions. Iron-(II)-phenantroline complexes were characterized by mass spectrometry. Well-defined, iron containing ionomer-type networks have been prepared. Networks can be act as good models for surface modification of magnetite nanopowder. Chloride-ion attachment technique by atmospheric pressure photoionization (APPI) was developed to investigate highly nonpolar polymers. The improved method gave the possibility to investigate the end groups of polyisobutylenes with different end groups and to determinate the number of the arms in case of bifunctional polymers, without fragmentation, using soft-ionization method

Sensing Layer for Ni Detection in Water Created by Immobilization of Bioengineered Flagellar Nanotubes on Gold Surfaces

The environmental monitoring of Ni is targeted at a threshold limit value of 0.34 mu M, as set by the World Health Organization. This sensitivity target can usually only be met by time-consuming and expensive laboratory measurements. There is a need for inexpensive, field-applicable methods, even if they are only used for signaling the necessity of a more accurate laboratory investigation. In this work, bioengineered, protein-based sensing layers were developed for Ni detection in water. Two bacterial Ni-binding flagellin variants were fabricated using genetic engineering, and their applicability as Ni-sensitive biochip coatings was tested. Nanotubes of mutant flagellins were built by in vitro polymerization. A large surface density of the nanotubes on the sensor surface was achieved by covalent immobilization chemistry based on a dithiobis(succimidyl propionate) cross-linking method. The formation and density of the sensing layer was monitored and verified by spectroscopic ellipsometry and atomic force microscopy. Cyclic voltammetry (CV) measurements revealed a Ni sensitivity below 1 mu M. It was also shown that, even after two months of storage, the used sensors can be regenerated and reused by rinsing in a 10 mM solution of ethylenediaminetetraacetic acid at room temperature