High Hydrogen Ion Concentration Causes a Blue Shift in Gold Nanoparticles

In this research, our team used a rare electrochemical method to obtain gold nanoparticles (GNPs). The growth solution has been added with nitric acid in order to observe the effect of GNPs. The solution also included cetyltrimethylammonium bromide (CTAB) and acetone. All reactions involved the oxidation of acetone and chain polymerization. Therefore, the GNPs changed to a su pramolecular structure. In addition, our team measured absorption wavelength via ultraviolet/ visible spectrophotometer and found an obviously blue shift. This short absorption wavelength is obviously different from other GNPs.

Direct immunofluorescence as a low-budget method for brain tissue inspection in standardization of neuroborreliosis animal model in NMRI mice

Objective. To test if the direct immunofluorescence can be used for the detection of Borrelia afzelii in brain tissue during the standardization of the animal model of neuroborreliosis in NMRI mice. Methods. The study was performed on 15 mice of NMRI strain. All mice were subcutaneously inoculated with 100 ml of BSK-H medium containing the local isolate of Borrelia afzelii. Animals were sacrificed after inoculation at III (n = 4), IV (n = 6) and V (n = 5) weeks, by cervical dislocation. In the sampled brains of mice, the presence of Borrelia was detected by direct immunofluorescence (DIF) and chain polymerization reaction (PCR). Results. The first brain tested positive for Borrelia three weeks after the inoculation. The bacteria were detected in 1 out of 4 brains (25%). After that, there was a growth in the percentage of positive results. The data showed that 3 out of 6 brains (50%) were found positive on Borrelia presence by the end of the fourth week. Whereas, in 3 out of 5 brains (60%) Borrelia was detected five weeks following the inoculation. Conclusion. According to the preliminary results, direct immunofluorescence appeared to be a practical, low budget method for following the kinetics of neuro-infection. NMRI mice could be considered as an adequate animal model for neuroborreliosis. Thus, more research is needed on the topics of infection kinetics for the period after fifth week post inoculation, as well as sensitivity and specificity of direct immunofluorescence.

Brief history of high-throughput nucleic acid sequencing methods.

The processes occurring during the enzymatic growth of the DNA chain in the form of elongation of the molecules, the release of pyrophosphate, proton, thermal energy, and an increase in electrical impedance, which are used in various methods of high-throughput DNA sequencing by synthesis, are briefly considered. The detection of DNA chain growth is controlled by high-voltage gel electrophoresis and has limited scalability. As for mentioned above other by-products of DNA chain polymerization, their detection can be easily scalable, which has led to the emergence of methods for whole genome sequencing of new generations of DNA, which have received the widely used abbreviation NGS - Next Generation Sequencing. However, the attribution of any new sequencing method to a particular generation is sometimes difficult due to the fact that the principle used in it was born earlier than the other one was implemented, which turned out to be less productive in the end. In addition, it is more important to distinguish the methods of new DNA sequencing into two groups in which the massive parallel sequencing of identical matrices takes place or the sequencing of single DNA molecules takes place and last one have received the designation monomolecular sequencing. In this review, along with the classical Sanger method of DNA sequencing, which is still the "gold standard", pyrosequencing, semiconductor sequencing, thermosequencing, electronic sequencing, fluorescent bridge sequencing and sequencing using nanoballs from the first group, as well as monomolecular methods – tSMS sequencing, SMRT sequencing and nanopore sequencing are considered. Attention is paid to the costs of DNA sequencing and the prospects for its development.

Elucidating the Inhibitory Effect of Resveratrol and Its Structural Analogs on Selected Nucleotide-Related Enzymes

Resveratrol, the most widely studied natural phytochemical, has been shown to interact with different target proteins. Previous studies show that resveratrol binds and inhibits DNA polymerases and some other enzymes; however, the binding and functioning mechanisms remain unknown. The elucidated knowledge of inhibitory mechanisms of resveratrol will assist us in new drug discovery. We utilized molecular docking and molecular dynamics (MD) simulation to reveal how resveratrol and structurally similar compounds bind to various nucleotide-dependent enzymes, specifically, DNA polymerases, HIV-1 reverse transcriptase, and ribonucleotide reductase. The results show that resveratrol and its analogs exert their inhibitory effects by competing with the substrate dNTPs in these enzymes and blocking elongation of chain polymerization. In addition, the results imply that resveratrol binds to a variety of other ATP-/NTP-binding proteins.

The Photoinitiator Lithium Phenyl (2,4,6-Trimethylbenzoyl) Phosphinate with Exposure to 405 nm Light Is Cytotoxic to Mammalian Cells but Not Mutagenic in Bacterial Reverse Mutation Assays

Lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) is a free radical photo-initiator used to initiate free radical chain polymerization upon light exposure, and is combined with gelatin methacryloyl (GelMA) to produce a photopolymer used in bioprinting. The free radicals produced under bioprinting conditions are potentially cytotoxic and mutagenic. Since these photo-generated free radicals are highly-reactive but short-lived, toxicity assessments should be conducted with light exposure. In this study, photorheology determined that 10 min exposure to 9.6 mW/cm2 405 nm light from an LED light source fully crosslinked 10 wt % GelMA with >3.4 mmol/L LAP, conditions that were used for subsequent cytotoxicity and mutagenicity assessments. These conditions were cytotoxic to M-1 mouse kidney collecting duct cells, a cell type susceptible to lithium toxicity. Exposure to ≤17 mmol/L (0.5 wt %) LAP without light was not cytotoxic; however, concurrent exposure to ≥3.4 mmol/L LAP and light was cytotoxic. No condition of LAP and/or light exposure evaluated was mutagenic in bacterial reverse mutation assays using S. typhimurium strains TA98, TA100 and E. coli WP2 uvrA. These data indicate that the combination of LAP and free radicals generated from photo-excited LAP is cytotoxic, but mutagenicity was not observed in bacteria under typical bioprinting conditions.