First Biphotochromic Fluorescent Protein moxSAASoti Stabilized for Oxidizing Environment

Biphotochromic proteins simultaneously possesses reversible photoswitching (on-to-off) and irreversible photoconversion (green-to-red). High photochemical reactivity of cysteine residues is one of the reasons for the development of “mox”-monomeric and oxidation resistant proteins. Based on site-saturated simultaneous two points C105 and C117 mutagenesis we have chosen the C21N/C71G/C105G/C117T/C175A as the moxSAASoti variant, since its on-to-off photoswitching rate is higher, off-to-on recovery is more complete and photoconversion rates are higher than for the mSAASoti. We analyzed the conformational behavior of the F177 side chain by classical MD simulations. The conformational flexibility of the F177 side chain is mainly responsible for the off-to-on conversion rate changes and can be further utilized as a measure of the conversion rate. Point mutations in the mSAASoti mainly affect the pKa values of the red form and the off-to-on switching. We demonstrate that the microscopic measure of the observed pKa value is the C – O bond length in the phenyl fragment of the neutral chromophore. According to the molecular dynamic simulations with the QM/MM potentials, larger C – O bond lengths are found for proteins with larger pKa. This feature can be utilized for prediction of the pKa values of red fluorescent proteins.

Elevated mean platelet volume in oral lichen planus and increased blood urea nitrogen level in its red-form: an observational study

Background This retrospective observational study aims to assess platelet count, mean platelet volume (MPV), blood biochemical tests for liver and kidney function in Chinese oral lichen planus (OLP) patients. Methods Eighty pathologically confirmed OLP patients and 51 healthy controls were enrolled. Data on full blood count and biochemical tests were obtained from the electronic medical record system of the hospital. Results MPV was elevated in OLP patients compared to controls (10.68 ± 0.97 fL versus 10.33 ± 0.89 fL, P = 0.042) while platelet count showed no difference between them. Red-form OLP group had increased blood urea nitrogen (BUN, 5.24 ± 1.15 mmol/L versus 4.69 ± 0.98 mmol/L, P = 0.036) than white-form OLP group. By contrast, there were no differences between those two groups in the other variables including MPV, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatinine. In terms of C-reactive protein (CRP), 92.5% of the OLP patients had a value of less than 3.48 mg/L. Besides, 75% of the OLP patients were overweight with body mass index (BMI) more than 25 kg/m2. Conclusions These findings indicate MPV might play roles in inflammation in OLP. The red-form OLP might be associated with damage or reduction of kidney function.

Тонкопленочные нелинейно-оптические кристаллы для внутрирезонаторной электрооптической модуляции

Methods for the preparation of DAST (4-N, N – dimethylamino–4'-N'-methyl stilbazolium tosylate) thin monocrystals with a thickness of a few micrometers, intended for electro-optics modulation were investigated. Thin-film single crystals are obtained, the shape and absorption spectrum of which confirms their crystalline structure of the “red” form DAST. Uniform color in the polarization contrast mode shows their monocrystallinity and uniform orientation. The materials are intended for intracavity modulation of laser radiation.

Novel Phototransformable Fluorescent Protein SAASoti with Unique Photochemical Properties

SAASoti is a unique fluorescent protein (FP) that combines properties of green-to-red photoconversion and reversible photoswitching (in its green state), without any amino acid substitutions in the wild type gene. In the present work, we investigated its ability to photoswitch between fluorescent red (‘on’) and dark (‘off’) states. Surprisingly, generated by 400 nm exposure, the red form of SAASoti (R1) does not exhibit any reversible photoswitching behavior under 550 nm illumination, while a combination of prior 470 nm and subsequent 400 nm irradiation led to the appearance of another—R2—form that can be partially photoswitched (550 nm) to the dark state, with a very fast recovery time. The phenomenon might be explained by chemical modification in the chromophore microenvironment during prior 470 nm exposure, and the resulting R2 SAASoti differs chemically from the R1 form. The suggestion is supported by the mass spectrometry analysis of the tryptic peptides before and after 470 nm light exposure, that revealed Met164 oxidation, as proceeds in another dual phototransformable FP, IrisFP.

Acaricide resistance in Tetranychus urticae red form (Acari: Tetranychidae) collected from strawberry in southern Turkey: Bioassay and biochemical studies

Recent population outbreaks of Tetranychus urticae Koch (red form) (Acari: Tetranychidae) were observed in strawberry fields in southern Turkey. Growers frequently complained that acaricides becoming an inefficient means of controlling this polyphagous pest. Therefore, a laboratory based bioassay and biochemical tests were conducted to determine comparative acaricide resistance status of five fields and a lab population of T. urticae. Larval bioassays were conducted using etoxazole and spiromesifen, whereas adult bioassays were performed with abamectin and tebufenpyrad. Kinetic esterase and glutathione S-transferase (GST) enzyme activities were also determined using a microplate reader. When compared to the lab population, based on LC50 values, the resistance rations of field populations were found between 2.39–7.86, 6.80–15.39, 4.61–9.73, and 5.51–12.47-fold for abamectin, etoxazole, spiromesifen and tebufenpyrad, respectively. Total esterase and GST activities of field populations were much higher than of the lab population. A 7.72–10.69 mOD/min/mg protein and a 5.92–7.56 mOD/min/mg protein, esterase and GST enzyme activities were determined for field populations, respectively. Whereas these enzyme activities were found to be 3.83 and 5.49 mOD/min/mg protein for the susceptible lab population, respectively. The higher detoxification enzyme activities indicate that these two enzymes play an important role in metabolic pathway of acaricides in different T. urticae populations.