SOD-Like Activity of Copper(II) Containing Metallopeptides Branched By 2,3-Diaminopropionic Acid: What the N-Termini Elevate,the C-Terminus Ruins

International Journal of Peptide Research and Therapeutics - Relations between structural modifiactions and SOD-like activity of four branched CuII-metallopeptides based on l-2,3-diaminopropionic...     

The 9th International Conference on Life Cycle Management 2019—Poznań, Poland, 1-4 September 2019 (www.lcm2019.org)

The International Journal of Life Cycle Assessment -     

Conformational solution studies of the SDS micelle-bound 11-28 fragment of two Alzheimer's beta-amyloid variants (E22K and A21G) using CD, NMR, and MD techniques

The beta-amyloid (Abeta) is the major peptide constituent of neuritic plaques in Alzheimer's disease (AD) and its aggregation is believed to play a central role in the pathogenesis of the disease. Naturally occurring mutations resulting in changes in the Abeta sequence (pos. 21-23) are associated with familial AD-like diseases with extensive cerebrovascular pathology. It was proved that the mutations alter the aggregation ability of Abeta and its neurotoxicity. Among five mutations at positions 21-23 there are two mutations with distinct clinical characteristics and potentially distinct pathogenic mechanism-the Italian (E22K) and the Flemish (A21G) mutations. In our studies we have examined the structures of the 11-28 fragment of the Italian and Flemish Abeta variants. The fragment was chosen because it has been shown to be the most important for amyloid fibril formation. The detailed structure of both variants Abeta(11-28) was determined using CD, 2D NMR, and molecular dynamics techniques under water-SDS micelle conditions. The NMR analysis revealed two distinct sets of proton resonances for the peptides. The studies of both peptides pointed out the existence of well-defined alpha-helical conformation in the Italian mutant, whereas the Flemish was found to be unstructured with the possibility of a bent structure in the central part of the peptide.     

A click chemistry approach to glycomimetics: Michael addition of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose to 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose--a convenient route to novel 4-deoxy-(1-->5)-5-C-thiodisaccharides

The base catalyzed conjugate Michael addition of the 1-thiosugar, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose, 1, to a new highly reactive enone 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose, 2, proceeds steroselectively with formation of adduct 3 in 94% yield. Convenient stereoselective reduction of the C-3 keto function of 3 with L-Selectride followed by in situ acetylation produces thiodisaccharide 4 in good 82% yield. Cleavage of the 1,2-O-isopropylidene protecting group with p-toluenesulfonic acid in methanol, followed by de-O-acetylation, produced an inseparable anomeric mixture of methyl 4-deoxy-5-C-(beta-D-glucopyranosyl)-thio-alpha/beta-L-ribo-pyranoside 5 in 72% overall yield. This approach constitutes a new general two-step click chemistry route to the previously unknown class of 4-deoxy-(1-->5)-5-C-thiodisaccharides as stable and biologically important glycomimetics.     

A cross-platform public domain PC image-analysis program for the comet assay

The single-cell gel electrophoresis, also known as the comet assay, has gained wide-spread popularity as a simple and reliable method to measure genotoxic and cytotoxic effects of physical and chemical agents as well as kinetics of DNA repair. Cells are generally stained with fluorescent dyes. The analysis of comets--damaged cells which form a typical comet-shaped pattern--is greatly facilitated by the use of a computer image-analysis program. Although several image-analysis programs are available commercially, they are expensive and their source codes are not provided. For Macintosh computers a cost-free public domain macro is available on the Internet. No ready for use, cost-free program exists for the PC platform. We have, therefore, developed such a public domain program under the GNU license for PC computers. The program is called CASP and can be run on a variety of hardware and software platforms. Its practical merit was tested on human lymphocytes exposed to gamma-rays and found to yield reproducible results. The binaries for Windows 95 and Linux, together with the source code can be obtained from: http://www.casp.of.pl.     

Occurrence of bacteria in the mouth from genera of Micrococcus,Kocuria, Nesterenkonia,Kytococcus and Dermacoccus

The aim of the study was to assess the prevalence of different bacteria in the oral cavity. The bacteria were present in the oral cavities of 73 (48.7%) of 150 individuals. Nesterenkonia halobia, the most frequently isolated species, was found in 20 (27%) individuals, Micrococcus luteus in 16 (22%), Kocuria kristinae in 12 (16%), Kocuria varians in 10 (14%), Dermacoccus sedentarius in 9 (12%), Micrococcus lylae in 8 (11%), and Kytococcus nishinomiyaensis in 3 (4%). Mean counts of these microorganisms were relatively low and amounted in log10 CFU/ml saliva for M. luteus 1.87 +/- 0.52, for M. lylae 2.03 +/- 0.39, for N. halobia 2.14 +/- 0.56, for K. kristinae 2.20 +/- 0.69, for K. varians 2.19 +/- 0.67, for K. nishinomiyaensis 1.72 +/- 0.39, and for D. sedentarius 2.27 +/- 0.55. The factor limiting the population sizes of these microorganisms was most probably the antagonistic activity of the bacteria living in oral cavity.     

NITROGEN FIXATION,HYDROGEN CYCLING,AND ELECTRON TRANSPORT KINETICS IN TRICHODESMIUM ERYTHRAEUM (CYANOBACTERIA) STRAIN IMS1011

This study describes the relationships between dinitrogen (N₂) fixation, dihydrogen (H₂) production, and electron transport associated with photosynthesis and respiration in the marine cyanobacterium Trichodesmium erythraeum Ehrenb. strain IMS101. The ratio of H₂ produced:N₂ fixed (H₂:N₂) was controlled by the light intensity and by the light spectral composition and was affected by the growth irradiance level. For Trichodesmium cells grown at 50 μmol photons · m^?2 · s^?1, the rate of N₂ fixation, as measured by acetylene reduction, saturated at light intensities of 200 μmol photons · m^?2 · s^?1. In contrast, net H₂ production continued to increase with light levels up to 1,000 μmol photons · m^?2 · s^?1. The H₂:N₂ ratios increased monotonically with irradiance, and the variable fluorescence measured using a fast repetition rate fluorometer (FRRF) revealed that this increase was accompanied by a progressive reduction of the plastoquinone (PQ) pool. Additions of 2,5‐dibromo‐3‐methyl‐6‐isopropyl‐p‐benzoquinone (DBMIB), an inhibitor of electron transport from PQ pool to PSI, diminished both N₂ fixation and net H₂ production, while the H₂:N₂ ratio increased with increasing level of PQ pool reduction. In the presence of 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU), nitrogenase activity declined but could be prolonged by increasing the light intensity and by removing the oxygen supply. These results on the coupling of N₂ fixation and H₂ cycling in Trichodesmium indicate how light intensity and light spectral quality of the open ocean can influence the H₂:N₂ ratio and modulate net H₂ production.