Decreased catalase activity is the underlying mechanism of oxidant susceptibility in glucose-6-phosphate dehydrogenase-deficient erythrocytes

Historically, it has been theorized that the oxidant sensitivity of glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes arises as a direct consequence of an inability to maintain cellular gluthione (GSH) levels. This study alternatively hypothesizes that decreased NADPH concentration leads to impaired to catalase activity which, in turn, underlies the observed oxidant susceptibility. To investigate this hypothesis, normal and G6PD-deficient erythrocytes and hemolysates were challenged with a H₂O₂-generating agent. The results of this study demonstrated that catalase activity was severely impaired upon H₂O₂ challenge in the G6PD-deficient cell whiel only decrease was observed in normal cells. Supplmentation of either normal or G6PD-deficient hemolysates with purified NADPH was found to significantly (P < 0.001) inhibit catalase inactivation upon oxidant challenge while addition of NADP⁺ had no effect. Analysis of these results demonstrated direct correlation between NADPH concentration and catalase activity (r = 0.881) and an inverse correlation between catalase activity and erythrocyte oxidant sensitivity (r = 0.906). In contrast, no correlation was found to exist between glutathione concentration (r = 0.170) and oxidant sensitivity. Analysis of NADPH/NADPt ration in acatalasemic mouse erythrocytes demonstrated that NADPH maintenance alone was not sufficient to explain oxidant resistance, and that catalase activity was required. This study supports the hypothesis that impaired catalase activity underlies the enhanced oxidant sensitivity of G6PD-deficient erythrocytes and elucidates the importance of NADPH in the maintenance of normal catalase activity.     

Oxidative Modification of Cysteine 111 Promotes Disulfide Bond-Independent Aggregation of SOD1

Converging evidence indicates that SOD1 aggregation is a common feature of mutant SOD1-linked fALS, and seems to be directly related to the gain-of-function toxic property. However, the mechanism inducing the aggregation is not understood. To study the contribution of oxidative modification of cysteine residues in SOD1 aggregation, we systematically examined the redox state of SOD1 cysteine residues in the G37R transgenic mouse model at different stages of the disease and under oxidative stress induced by H₂O₂. Our data suggest that under normal circumstance, cysteine 111 residue in SOD1 is free; however, under oxidative stress, it is prone to oxidative modification by providing the thiolate anion (S−). With the progression of the disease, increased levels of oxidative insults facilitated the oxidation of thiol groups of cysteine residues; human mutant SOD1 could generate an upper shift band in reducing SDS-PAGE, which turned out to be a Cys111-peroxidized SOD1 species. We also detected the formation of SOD1 multimers at different stages of the disease, and found that accumulated oxidative stress facilitated the formation of aggregates, which were not mediated by disulfide bond. This oxidative modification of cysteine 111 therefore promotes the formation of disulfide bond-independent aggregation of SOD1.     

Distribution of glyphosate and methylphosphonate catabolism systems in soil bacteria <Emphasis Type="Italic">Ochrobactrum anthropi</Emphasis> and <Emphasis Type="Italic">Achromobacter</Emphasis> sp

Bacterial strains capable of utilizing methylphosphonic acid (MP) or glyphosate (GP) as the sole sources of phosphorus were isolated from soils contaminated with these organophosphonates. The strains isolated from MP-contaminated soils grew on MP and failed to grow on GP. One group of the isolates from GP-contaminated soils grew only on MP, while the other one grew on MP and GP. Strains Achromobacter sp. MPS 12 (VKM B-2694), MP degraders group, and Ochrobactrum anthropi GPK 3 (VKM B-2554D), GP degraders group, demonstrated the best degradative capabilities towards MP and GP, respectively, and were studied for the distribution of their organophosphonate catabolism systems. In Achromobacter sp. MPS 12, degradation of MP was catalyzed by C–P lyase incapable of degrading GP (C–P lyase I). Adaptation to growth on GP yielded the strain Achromobacter sp. MPS 12A, which retained its ability to degrade MP via C–P lyase I and was capable of degrading GP with formation of sarcosine, thus suggesting the involvement of a GP-specific C–P lyase II. O. anthropi GPK 3 also degraded MP via C–P lyase I, but degradation of GP in it was initiated by glyphosate oxidoreductase, which was followed by product transformation via the phosphonatase pathway.     

Migration of Sakhalin taimen (<Emphasis Type="Italic">Parahucho perryi</Emphasis>): evidence of freshwater resident life history types

Sakhalin taimen (Parahucho perryi) range from the Russian Far East mainland along the Sea of Japan coast, and Sakhalin, Kuril, and Hokkaido Islands and are considered to primarily be an anadromous species. We used otolith strontium-to-calcium ratios (Sr/Ca) to determine the chronology of migration between freshwater and saltwater and identify migratory contingents of taimen collected from the Koppi River, Russia. In addition, we examined taimen from the Sarufutsu River, Japan and Tumnin River, Russia that were captured in marine waters. Transects of otolith Sr/Ca for the Sarufutsu River fish were consistent with patterns observed in anadromous salmonids. Two fish from the Tumnin River appeared to be recent migrants to saltwater and one fish was characterized by an otolith Sr/Ca transect consistent with marine migration. Using these transects as benchmarks, all Koppi River taimen were classified as freshwater residents. These findings suggest more work is needed to assess life history variability among locations and the role of freshwater productivity in controlling migratory behavior in taimen.     

<Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of a PEO-Gellan Gum Semi-Interpenetrating Polymer Network for the Oral Delivery of Sulpiride

In this study, an optimized epichlorohydrin-crosslinked semi-interpenetrating polymer network xerogel matrix system (XePoMas) for the controlled delivery of sulpiride was prepared. The ability of XePoMas to sustain drug release was determined by in vitro and in vivo drug release experiments. Swelling of the xerogel over the 24-h experimental period ranged from 346 to 648%; swelling was observed to increase exponentially over the initial 8 h. In vitro drug release depicted a linear zero order drug release profile with an R ² value of 0.9956. The ability of the fabricated XePoMas to sustain drug release and enhance bioavailability of sulpiride in vivo was investigated by evaluating the plasma drug concentration over 24 h in the large pig model. The optimized XePoMas formulation was shown to increase intestinal absorption of sulpiride to a greater extent than the marketed product in vivo, with a C _max of 830.58 ng/mL after 15 h.     

Lidocaine-loaded fish scale-nanocellulose biopolymer composite microneedles

Microneedle (MN) technology has emerged as an effective drug delivery system, and it has tremendous potential as a patient friendly substitute for conventional methods for transdermal drug delivery (TDD). In this paper, we report on the preparation of lidocaine-loaded biodegradable microneedles, which are manufactured from fish scale-derived collagen. Lidocaine, a common tissue numbing anaesthetic, is loaded in these microneedles with an aim of delivering the drug with controlled skin permeation. Evaluation of lidocaine permeation in porcine skin has been successfully performed using Franz diffusion cell (FDC) which has shown that the drug permeation rate increases from 2.5 to 7.5% w/w after 36 h and pseudo steady state profile is observed from 5.0 to 10.0% w/w lidocaine-loaded microneedle. Swelling experiments have suggested that the microneedles have negligible swellability which implies that the patch would stick to the tissue when inserted. The experiments on MN dissolution have depicted that the lidocaine loaded in the patch is lower than the theoretical loading, which is expected as there can be losses of the drug during initial process manufacture.     

Statistical analysis and optimization of biodiesel production from waste coffee grounds by a two-step process

Biodiesel was produced using waste coffee grounds (WCGs) via a two-step process comprising lipid extraction and subsequent transesterification steps. Each step was statistically analyzed, and optimum conditions for each step were suggested. WCGs were found to have 16.4% lipid content with 1.9% free fatty acid (FFA) content. The liquid-solid ratio (LSR) significantly influenced lipid extraction from WCGs, while extraction time and temperature did not; 92.7% of lipid extraction efficiency was achieved at 13.7 mL-hexane/g-WCGs, 30 min of extraction time, and 25°C. Owing to the relatively low FFA content, an alkaline catalyst (NaOH) reaction was used that requires less amount of catalyst, methanol, and shorter reaction time compared to an acid catalyst reaction. Reaction time and temperature were the major factors affecting biodiesel conversion, and 94.0% of biodiesel conversion was obtained at optimum conditions for transesterification: 0.5% catalyst, 1.5 mL-methanol/g-lipid, 45°C, and 9 h of reaction time. With the use of statistical analysis tools, high lipid extraction efficiency and biodiesel conversion were achieved at relatively mild conditions, which would reduce biodiesel production cost substantially.     

Relationship of self-mutilative behaviour with history of childhood trauma and adult ADHD symptoms in a sample of inpatients with alcohol use disorder

The aim of the present study was to evaluate relationship of self-mutilative behaviour (SMB) with the severity of childhood trauma and adult attention-deficit/hyperactivity disorder (ADHD) symptoms in a sample of inpatients with alcohol use disorder (AUD). Participants included 188 inpatients with AUD. Participants were evaluated with the Self-mutilative Behaviour Questionnaire, the Childhood Trauma Questionnaire (CTQ-28) and the Adult ADD/ADHD DSM-IV Based Diagnostic Screening and Rating Scale (Adult ADHD Scale). Among inpatients with AUD those who have a history of SMB constituted the SMB group (n = 57, 30.3%), and those without a history of SMB constituted the group without SMB (n = 131, 69.7%). Risk of high ADHD risk was 2.5 times higher among those with SMB. Adult ADHD Scale and CTQ-28 scores were also higher in the group with SMB. In the first backward logistic regression model, the severity of ADHD symptoms predicted the presence of SMB, together with the severity of childhood trauma, whereas in the second model, physical neglect and inattentive (IN) dimension of ADHD predicted the presence of SMB. These findings suggest that the higher severity of physical neglect and adult IN dimension of ADHD may be related to SMB among inpatients with AUD.