Inhibition of α-glucosidase activity by curcumin loaded on ZnO@rGO nanocarrier for potential treatment of diabetes mellitus

Curcumin (Cur) is an acidic polyphenol with some effects on α-glucosidase (α-Glu), but Cur has disadvantages such as being a weak target, lacking passing the blood–brain barrier and having low bioavailability. To enhance the curative effect of Cur, the hybrid composed of ZnO nanoparticles decorated on rGO was used to load Cur (ZnO@rGO-Cur). The use of the multispectral method and enzyme inhibition kinetics analysis certify the inhibitory effect and interaction mechanism of ZnO@rGO-Cur with α-Glu. The static quenching of α-Glu with both Cur and ZnO@rGO-Cur is primarily driven by hydrogen bond and van der Waals interactions. The conformation-changing ability by binding to the neighbouring phenolic hydroxyl group of Cur increased their ability to alter the secondary structure of α-Glu, resulting in the inhibition of enzyme activity. The inhibition constant (K_{i, Cur} > K_{is,ZnO@rGO-Cur} ) showed that the inhibition effect of ZnO@rGO-Cur on α-Glu was larger than that of Cur. The CCK-8 experiments proved that ZnO@rGO nanocomposites have good biocompatibility. These results suggest that the therapeutic potential of ZnO@rGO-Cur composite is an emerging nanocarrier platform for drug delivery systems for the potential treatment of diabetes mellitus.     

Role of Tim21 in mitochondrial translocation contact sites

Translocation of preproteins with N-terminal presequences into mitochondria requires the cooperation of the translocase of the outer membrane (TOM complex) and the presequence translocase of the inner membrane (TIM23 complex). However, the molecular nature of the translocation contact sites is poorly understood. We have identified a novel component of the TIM23 translocase, Tim21, which is involved in their formation. Tim21 is anchored in the mitochondrial inner membrane by a single transmembrane domain and exposes its C-terminal domain into the intermembrane space. The purified C-terminal domain of Tim21 appears not to bind to any of the TIM23 components but rather specifically interacts with the TOM complex. We propose that Tim21 binds to the trans site of the TOM complex thus keeping the two translocases in close contact.     

The impact of anthropometric parameters on the incidence of low back pain

Endogenic factors as one of possible reasons for low back pain were investigated and discussed in this study. The study included 122 male bus drivers, average age 44.2 years, average period of active service 24.4 years. The following anthropometric indexes have been calculated: Quetelet's index, percentage of body fat, relative body weight, Olivier's typologic index, Lorenz's constitution index and muscle index. According to inquiry form regarding history of low back pain the subjects were divided in two groups: 36 had no low back pain history and 76 had a history of recurrent low back pain. The results showed statistically nonsignificant differences in the anthropometric parameters and the calculated indexes between these two groups of subjects. The chosen subject sample showed that nutritional status, body build, constitution and muscular development are not associated with the incidence of low back pain.     

Oligo-chip based detection of tick-borne bacteria

We have developed an oligonucleotide-chip based assay for detection of 16S ribosomal PCR products from tick-borne bacteria. This chip contains 14 specific probes, which target variable regions of 16S rDNA of tick-borne bacteria including Borrellia spp., Rickettsia spp., Anaplasma spp., Coxiella burnetii and Francisella tularensis. The specificity of these probes was tested by hybridization of the chip with fluorescently labeled PCR products amplified from the genomic DNA of selected tick-borne bacteria. The assay was also tested for detection of tick-borne bacteria in single ticks.     

Ultrastructure and cell death of in vivo derived and vitrified porcine blastocysts

Morphological and molecular signs of injury and cell death and subsequent regeneration following vitrification of porcine blastocysts were evaluated by light (LM) and transmission electron microscopy (TEM) as well as TUNEL/propidium iodide (PI) nuclear staining followed by confocal microscopy (CSM). In vivo derived blastocysts were assigned to one of the following four groups: Controls-(1) fixed immediately after collection (C0h) and (2) after 24 hr culture in vitro (C24h) and vitrified embryos-(3) fixed immediately after vitrification and warming (V0h), and (4) after 24 hr of culture upon warming after vitrification (V24h). Observation by LM and TEM showed that the V0h embryos displayed collapse of the blastocoele cavity (BC) and cell swelling, a general distension or shrinkage of mitochondria and massive increase in the amount of vesicles, vacuoles, and secondary lysosomes (SLs). Approximately 2/3 of the V24h embryos had recovered, whereas the remaining 1/3 were degenerated. Recovered embryos displayed almost normal blastocyst morphology, except for a widening of the perivitelline space, accumulation of debris and partial distension of mitochondria, whereas degenerated embryos were disintegrated into a poorly defined mass of cells and debris including cells with abundant degeneration of mitochondria and other organelles. Both recovered and degenerated embryos displayed a persistent abundance of presence of small membrane bounded vesicles, vacuoles, and SLs. Evaluation of TUNEL/PI stained embryos showed only occasional appearance of TUNEL positive nuclei with typical apoptotic morphology in controls (C0h 0.67%, C24h 1.22%) and in the V0h embryos (0.93%). The percentage of apoptotic nuclei in embryos at V24h was significantly higher than in all other groups (2.64%). Vitrified embryos showed significantly increased appearance of DNA fragmented nuclei without typical morphological features of apoptosis (V0h 1.43%, V24h 4.30%) compared with controls (C0h 0.26%, C24h 0.45%). The observed morphological changes and increased DNA fragmentation observed immediately after vitrification and warming probably reflects a direct damaging effect of vitrification. During 24 hr of culture a portion of the embryos was able to regenerate and along with the regenerative process, apoptosis--a possible pathway for elimination of damaged cells--became evident.     

A theoretical study on effect of the initial redox state of cytochrome b559 on maximal chlorophyll fluorescence level (F(M)): implications for photoinhibition of photosystem II

In this work, we extended the reversible radical pair model which describes energy utilization and electron transfer up to the first quinone electron acceptor (Q(A)) in photosystem II (PSII), by redox reactions involving cytochrome (cyt) b559. In the model, cyt b559 accepts electrons from the reduced primary electron acceptor in PSII, pheophytin, and donates electrons to the oxidized primary electron donor in PSII (P680+). Theoretical simulations of chlorophyll fluorescence rise based on the model show that the maximal fluorescence, F(M), increases with an increasing amount of initially reduced cyt b559. In this work we applied, the first to our knowledge, metabolic control analysis (MCA) to a model of reactions in PSII. The MCA was used to determine to what extent the reactions occurring in the model control the F(M) level and how this control depends on the initial redox state of cyt b559. The simulations also revealed that increasing the amount of initially reduced cyt b559 could protect PSII against photoinhibition. Also experimental data, which might be used to validate our theory, are presented and discussed.     

Analysis of liquid extracts from tree and grass pollens by capillary electromigration methods

Capillary electromigration methods, zone electrophoresis (CZE), micellar electrokinetic chromatography (CMEKC) and isotachophoresis (CITP), have been used for analysis of water and water-buffer extracts from tree-common birch (Betula verrucosa) and grass-orchardgrass (Dactylis glomerata) pollen samples. Water extracts were analyzed by CZE using acetic acid as background electrolyte (BGE), by CMEKC in tris-phosphate BGE with anionic detergent sodium dodecyl sulfate (SDS) micellar pseudophase (TP-SDS) and by CITP in cationic mode with leading/terminating cations K+/BALA+ (beta-alanine (BALA)) and in anionic mode with leading/terminating anions Cl-/MES- (2-(N-morpholino)ethanesulphonic acid (MES)). Moreover, acetic acid extracts were analyzed by CZE using acetic acid as BGE, and alkaline water-SDS-buffer extracts were analyzed by CMEKC using TP-SDS as BGE. Extracted amounts of pollen allergens and other UV-absorbing compounds and the number of resolved components were evaluated from CZE, CMEKC and CITP analyses of the liquid extracts. Larger amounts of UV-absorbing material were found in the water-buffer pollen extracts than in the water extracts. More UV-absorbing material was found in all extracts from D. glomerata pollen than in relevant extracts from B. verrucosa pollen. It was found by CITP that the extracted amounts of anionic components and their number were much higher than those of cationic components. Concentrations of some inorganic ions (e.g. Cl-, K+, Na+, Ca2+) in pollen samples were also determined by CITP.     

Fine Structural in Situ Analysis of Nascent DNA Movement Following DNA Replication

Nascent DNA (newly replicated DNA) was visualized in situ with regard to the position of the previously replicated DNA and to chromatin structure. Localization of nascent DNA at the replication sites can be achieved through pulse labeling of cells with labeled DNA precursors during very short periods of time. We were able to label V79 Chinese Hamster cells for as shortly as 2 min with BrdU; Br-DNA, detected by immunoelectron microscopy, occurs at the periphery of dense chromatin, at individual dispersed chromatin fibers, and within dispersed chromatin areas. In these regions DNA polymerase α was also visualized. After a 5-min BrdU pulse, condensed chromatin also became labeled. When the pulse was followed by a chase, a larger number of gold particles occurred on condensed chromatin. Double-labeling experiments, consisting in first incubating cells with IdU for 20 min, chased for 10 min and then labeled for 5 min with CldU, reveal CldU-labeled nascent DNA on the periphery of condensed chromatin, while previously replicated IdU-labeled DNA has been internalized into condensed chromatin. Altogether, these results show that the sites of DNA replication correspond essentially to perichromatin regions and that the newly replicated DNA moves rapidly from replication sites toward the interior of condensed chromatin areas.     

Velocity auto-correlation function of ions and water molecules in different concentrations,anions and ion clusters

The characteristics of ion solvation are important for electrochemical and biophysical phenomena because all such phenomena occur under the presence of solvated ions. In this study, we performed an all-atom molecular dynamics simulation of aqueous NaCl ranging from 0.5 to 3.0 M, and aqueous NaF, NaBr and NaI in 2.0 M, to investigate the time-averaged velocity auto-correlation function (TAVAF) of ions and water molecules. By comparing the concentrations and ion pairs, we observed three behaviours: (i) in the case of NaCl, the velocity auto-correlation of Cl^?  becomes weaker as the concentration increases, whereas those of Na⁺ are not clearly different, (ii) the intensity of fluctuations of the TAVAF gradually decreases following the decrease in ionic radius and (iii) every TAVAF of water molecules in ionic solutions is clearly lower than that of bulk because of the cage effect. Furthermore, we observed that the first minimum of the TAVAF in the cluster is smaller than that of the isolated ions. These results indicate that the diffusion of ions and water molecules is affected by cage effect, and that the generation of ion cluster affects the diffusion of ions.