Structure-Activity Relationship Study of N-Hydroxyphtalimide Derivatives for the Detection of Amines during Fmoc-Solid-Phase Peptide Synthesis.

Previously, we developed a method for the detection of unprotected amino groups based on their reversible reaction with N-hydroxyphthalimide (NHPI) to form intensely colored products, which can be useful when conducting solid-phase peptide synthesis. Here, we describe a structure-activity relationship study of NHPI derivatives to identify the derivative best suited for this method using a spectrophotometer toward the estimation of chemical yields. We found that the products resulting from the reaction of the derivative with an unprotected amino group were only intensely colored if the structure of the derivative incorporated an NHPI framework. We also prepared five peptides, including those containing N-methyl and D-amino acid, and Pro residues, using our reversible detection method to detect unprotected amino groups. The mechanism of the detection reaction was also studied by the structural analysis of the NHPI (1) and diisopropylamine complex and concluded to entail salt formation between the N-hydroxy group and amine.

Antimicrobial activity and secondary structure of a novel peptide derived from ovalbumin.

A novel antimicrobial peptide derived from ovalbumin has been discovered. First, the peptide fragment RKIKVYLPRMK (TK9.1) was identified based on computerized predictions of the secondary structure of peptides in a protein data bank. Using HeliQuest, the sequence was developed into RKIKRYLRRMI (TK9.1.3), which was synthesized using Fmoc-solid phase peptide synthesis, and found to have strongly antimicrobial activity against Gram-positive and Gram-negative bacteria, and fungi but not cytotoxic to HeLa cells and hemolysis in mouse red blood cells. Although ovalbumin itself does not have an antibacterial activity, our results suggest that it may supply the organisms that consume it with antimicrobial peptides, in support of their immunodefence.

Comparison of the Effects of Continuous and Intermittent Exercise on Cerebral Oxygenation and Cognitive Function.

Cognitive function is reported to improve by moderate aerobic exercise. However, the effects of intermittent exercise with rest between the moderate-intensity exercise are unclear. Therefore, this study aimed to compare the effects of continuous and intermittent exercise on cerebral oxygenation and cognitive function. This study included 18 healthy adults. For the continuous exercise protocol, 5 min of rest was followed by 30 min of exercise; 5 min of rest was allowed after each exercise. For the intermittent exercise protocol, 3 sets of 10 min of exercise were completed, with 5 min of rest between the sets. Exercise intensity was 50% of maximum oxygen uptake. Oxyhemoglobin (O2Hb) in the prefrontal cortex (PFC) was measured during each protocol, and cognitive tasks (Stroop test) were performed before and after exercise. O2Hb levels for the left and right PFCs were significantly higher post-exercise than pre-exercise for both exercise protocols (p < 0.01). The average reaction time in the Stroop test was significantly shorter post-exercise than pre-exercise for both protocols (p < 0.01). There was no significant difference in the error rate pre- and post-exercise for both protocols (continuous p = 0.22; intermittent p = 0.44). There was no significant difference between both protocols in all measurement results (O2Hb: p = 0.67; average reaction time p = 0.50; error rate p = 0.24). O2Hb was higher and average reaction time was shorter after exercise than before exercise for both exercise protocols. Intermittent and continuous exercise may improve cognitive function to the same degree after exercise.

Poly(cyclohexylsilsesquioxane)-Based Hydrophilic Thermoset-Resistant Deep-Ultraviolet-Transparent Glasses with Low Melting Temperatures.

Silsesquioxane (SQ)-based glasses with low melting temperatures were prepared by the cosolvent-free (solventless) hydrolytic polycondensation of organotrimethoxysilanes with cyclopentyl (c-Pe) and cyclohexyl (c-Hx) groups. Copolymers consisting of phenylsilsesquioxane (Ph-SQ) units and c-Pe-SQ units [poly(Ph-co-c-Pe-SQ)] or c-Hx-SQ units [poly(Ph-co-c-Hx-SQ)] were melted at 140 °C and formed clear glasses. The glasses prepared by this method contained many residual SiOH groups and exhibited high adhesive strength to microscope glass plates, metals, and several polymers. The glass-transition temperature of poly(c-Hx-SQ) was lower than that of poly(Ph-SQ) by only a small margin, whereas that of poly(c-Pe-SQ) was much lower. The poly(c-Hx-SQ)-based glasses were stiff at room temperature and transparent in the deep-ultraviolet spectral region (≲300 nm). They formed fragile melts with kinetic fragility parameters as high as ∼0.8. The melts of poly(c-Hx-SQ) and poly(c-Hx-co-Et-SQ) exhibited better resistance to thermal curing than that of poly(Ph-SQ) and maintained thermoplasticity even after heat treatment at 200 °C for 6 h.

Stain Protocol for the Detection of N-Terminal Amino Groups during Solid-Phase Peptide Synthesis.

A novel and reversible detection method for N-terminal amino groups and alternative to the Kaiser test during Fmoc-SPPS has been developed. The utility of the new method was exemplified in its monitoring of the construction of a peptide, the final yield of which was higher than that of an identical peptide constructed under identical conditions but using the Kaiser test, and its scope was established to include all 20 proteinogenic amino acids as well as nonproteinogenic ones.

New Mydriasis-Free Electroretinogram Recorded with Skin Electrodes in Healthy Subjects.

PURPOSE: To evaluate the reproducibility and consistency of the new mydriasis-free electroretinogram (ERG) with a skin electrode (RETeval) device, to determine the normative values of parameters, and to clarify the usefulness of pupil records to colored-light stimulus. METHODS: A total of 100 eyes of 50 healthy subjects (mean age, 21.4 years) were enrolled. The diagnostic parameters obtained by the RETeval device were examined under the following conditions. The reproducibility was determined with the coefficient of variation (CV). The consistency was examined by intraclass correlation coefficients (ICCs). The mean value and the normal range were analyzed with a 95% confidence interval as the normative values of parameters. The correlation of parameters to pupil records (area ratio, constriction ratio) and flicker ERG was also examined in the diabetic retinopathy assessment protocol. RESULTS: From the CV for each of the two measurements, the amplitude has a low reproducibility compared with the implicit time. Generally good consistency was obtained with both ERG parameters (ICCs = 0.48-0.92). Moderate correlations were found for the white-, red-, and blue-light stimulus in the area ratio and the constriction ratio, respectively (r = 0.44-0.62; P = 0.010-<0.0001). No correlation was observed between pupil and flicker parameters (r = 0.06-0.34; P = 0.646-0.051). CONCLUSIONS: The RETeval device was suggested as a possible screening device to detect the visual afferent diseases by evaluating in combination with the ERG recording and the colored-light pupil response.