Improvement of the stability of glucose oxidase via encapsulation in sodium alginate–cellulose sulfate–poly(methylene-co-guanidine) capsules

Encapsulation of glucose oxidase (GOD) in polyelectrolyte complex capsules and its influence on properties of the enzyme is reported. The immobilization of GOD in the capsules made of sodium alginate (SA), cellulose sulfate (CS), poly(methylene-co-guanidine) (PMCG), CaCl₂ and NaCl (GOD–SA–CS/PMCG capsules) was achieved using a one-step highly reproducible encapsulation protocol which was monitored by a Electrospray Ionization-Mass Spectrometry (ESI-MS). A leakage of the enzyme from the capsules was negligible. Encapsulated GOD exhibited higher thermostability, wider range of pH optimum and improved storage stability in comparison with free GOD. The 92% retained activity by the encapsulated GOD after 45 biooxidation cycles was markedly higher than that of the GOD entrapped in calcium pectate gel beads showing no activity after 12 cycles. Optimization of conditions of oxygen supplementation resulted in increased oxygen availability within the GOD–SA–CS/PMCG capsules. Oxygen supplementation was accompanied with a mild decrease in the mechanical resistance of the SA–CS/PMCG capsules.     

A Platform for Generation of Chamber-Specific Cardiac Tissues and Disease Modeling

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Label-free mass spectrometric profiling of urinary proteins and metabolites from paediatric idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome (INS) is caused by renal diseases that increase the permeability of the glomerular filtration barrier without evidence of a specific systemic cause. The aim of the present work was to reveal inherent molecular features of INS in children using combined urinary proteomics and metabolomics profiling. In this study, label-free mass spectrometric analysis of urinary proteins and small molecule metabolites was carried out in 12 patients with INS versus 12 sex- and age-matched control subjects with normal renal function. Integration and biological interpretation of obtained results were carried out by Ingenuity IPA software. Validation of obtained proteomics data was carried out by Western blot method. Proteomics data have been deposited to the ProteomeXchange Consortium with the data set identifier PXD000765. This study indicates for the first time that paediatric INS is associated with up-regulation of afamin, hydroxyphenylacetate and uridine, and concomitant down-regulation in glutamine and phenylalanine levels, and many of these molecular species were previously shown to be involved in oxidative stress. Further studies in larger patient population are underway to investigate the role of oxidative stress in renal injury in paediatric INS.     

Beneficial effects of ceftriaxone against pentylenetetrazole-evoked convulsions

Although considered to be generally safe, a number of beta-lactam antibiotics have been associated with epileptic seizures in humans. Furthermore, some beta-lactam antibiotics, including ceftriaxone, are used to evoke convulsions under experimental conditions. Recently it was demonstrated that ceftriaxone increased expression of the glutamate transporter (GLT1) and its biochemical and functional activity in the brain of rodents. GLT1 regulates extracellular concentrations of glutamate, an excitatory amino acid involved in the pathogenesis of seizures and epilepsy. Because of its rapid transfer of glutamate into neurons and adjacent glial cells, GLT1 diminishes glutamate toxicity. We investigated whether ceftriaxone (200 mg/kg body wt) administered intraperitoneally (ip) for 6 days could modify the convulsant effects of pentylenetetrazole (PTZ, 100 mg/kg ip) in inbred male BALBcAnNCR and C57 black (BL)/6 mice aged 4 and 12 weeks. Ceftriaxone pretreatment provided significant protective effects against PTZ-evoked generalized clonic convulsions (GCCs), generalized clonic-tonic convulsions (GCTCs), and convulsion-induced mortality during a period of 30 mins after PTZ administration. The incidence of GCCs, GCTCs, and death was statistically significantly lower for BALBcAnNCR mice of both ages, particularly younger mice. The latency time for each of the three parameters was significantly greater, with the exception of GCCs in adult mice. Protective effects of ceftriaxone were also noticed in adult C57BL/6 mice but not in prepubertal C57BL/6 mice. This is the first demonstration of anticonvulsant effects of ceftriaxone or any other beta-lactam antibiotic, which are not uniform across the mouse population. Our results provide new insight into the effects of ceftriaxone, which need further investigation.     

Green and blue light photoreceptors are involved in maintenance of dormancy in imbibed annual ryegrass (Lolium rigidum) seeds

Light plays an important role in two separate processes within the seeds of Lolium rigidum (annual ryegrass). Dormant seeds of L. rigidum remain dormant when imbibed in the light, but once seeds have lost dormancy through dark-stratification, light stimulates their germination. This study characterizes the light qualities and quantities which are effective in maintenance of dormancy. Dormant seeds were stratified under narrow- and broad-waveband light to identify the potential photoreceptors involved in dormancy maintenance, and to determine whether dark-induced dormancy loss is reversible by light. Blue and green light both mediated dormancy maintenance in a far-red-independent manner. Red light resulted in dormancy maintenance only when far-red wavelengths were excluded, suggesting a redundant function of phytochrome. At low fluence rates, white light was more effective than monochromatic light, suggesting the action of multiple photoreceptors in dormancy maintenance. By contrast, nondormant seeds did not germinate unless provided with red light. These results indicate that seed dormancy maintenance is potentially mediated through the actions of blue and green light photoreceptors. Seed dormancy could thus be added to the growing list of plant responses that may be mediated by green light in a cryptochrome-independent manner.     

Silicon alleviates the negative effects of arsenic in poplar callus in relation to its nutrient concentrations

Plant Cell, Tissue and Organ Culture (PCTOC) - The contamination of water and soil by arsenic (As) is a global environmental, health, and agricultural issue. The study of As toxicity in plants and...     

Free radical-induced endothelial membrane dysfunction at the site of blood-brain barrier: Relationship between lipid peroxidation,Na,K-ATPase activity,and51Cr release

Na,K-ATPase activity, membrane lipid peroxidation (TBARM), and membrane leakiness for small molecules were examined in rat cerebromicrovascular endothelial cells (RCEC) following exposure to hydrogen peroxide and xanthine/xanthine oxidase. Whereas short-term (15–30 min) exposure to either oxidant decreased ouabain-sensitive⁸⁶Rb uptake and increased TBARM in a concentration-dependent fashion, significant release of⁵¹Cr (30–40%) from cells was observed only after one hour exposure to the oxidants. By comparison, much longer exposure times (i.e., 4 hours) were needed to induce significant lactate dehydrogenase release from oxidant-treated cells. The oxidant-evoked decrease in Na,K-ATPase activity and increases in TBARM and RCEC permeability were abolished in the presence of the steroid antioxidants U-74500A and U-74389G (5–20 M). Reduced glutathione (4 mM) partially attenuated oxidant-induced changes, whereas ascorbic acid (2 mM) and the disulfide bond-protecting agent, dithiothreitol (1 mM), were ineffective. These results suggest that the oxidant-induced loss of Na,K-ATPase activity in RCEC results primarily from changes in membrane lipids, and implicate both the inhibition of Na,K-ATPase and membrane lipid peroxidation in the mechanism responsible for the delayed free radical-induced increase in RCEC membrane permeability.     

The Glycoprotein Character of Multiple Forms of Aspergillus Polygalacturonase

Comparisons of known primary structures of polygalacturonases show that extent and localization of potential N-glycosylation sites differ. Some sites are similar in position and adjacent to strictly conserved residues at the potential active site. The presence of N-acetylglucosamine and mannose in the molecules of two homogeneous, major Aspergillus sp. polygalacturonase forms was confirmed by IR spectroscopy. The purification method, based on interaction of the carbohydrate part with concanavalin A immobilized on chlorotriazine bead cellulose, was optimized. Deglycosylation with N-glycosidase F under denaturating and nondenaturating conditions led to molecular mass decreases followed by complete inactivation of the polygalacturonase enzyme activity. These results show the importance of glycosylation in these protein forms, while the comparative patterns establish both variability and some similarities in overall glycosylation architectures.     

Resolution and prevention of feline immunodeficiency virus-induced neurological deficits by treatment with the protease inhibitor TL-3

In vivo tests were performed to assess the influence of the protease inhibitor TL-3 on feline immunodeficiency virus (FIV)-induced central nervous system (CNS) deficits. Twenty cats were divided into four groups of five animals each. Group 1 received no treatment, group 2 received TL-3 only, group 3 received FIV strain PPR (FIV-PPR) only, and group 4 received FIV-PPR and TL-3. Animals were monitored for immunological and virological status, along with measurements of brain stem auditory evoked potential (BAEP) changes. Groups 1 and 2 remained FIV negative, and groups 3 and 4 became virus positive and seroconverted by 3 to 5 weeks postinoculation. No adverse effects were noted with TL-3 only. The average peak viral load for the virus-only group 3 animals was 1.32 x 10(6) RNA copies/ml, compared to 6.9 x 10(4) copies/ml for TL-3-treated group 4 cats. Group 3 (virus-only) cats exhibited marked progressive delays in BAEPs starting at 2 weeks post virus exposure, which is typical of infection with FIV-PPR. In contrast, TL-3-treated cats of group 4 exhibited BAEPs similar to those of control and drug-only cats. At 97 days postinfection, treatments were switched; i.e., group 4 animals were taken off TL-3 and group 3 animals were treated with TL-3. BAEPs in group 3 animals returned to control levels, while BAEPs in group 4 animals remained at control levels. After 70 days on TL-3, group 3 was removed from the drug treatment regimen. Delays in BAEPs immediately increased to levels observed prior to TL-3 treatment. The findings show that early TL-3 treatment can effectively eliminate FIV-induced changes in the CNS. Furthermore, TL-3 can counteract FIV effects on the CNS of infected cats, although continued treatment is required to maintain unimpaired CNS function.     

Conserving the Sacred Medicine Mountains: A Vegetation Analysis of Tibetan Sacred Sites in Northwest Yunnan

Mount Kawa Karpo of the Menri ('Medicine Mountains' in Tibetan), in the eastern Himalayas, is one of the most sacred mountains to Tibetan Buddhists. Numerous sacred sites are found between 1900 and 4000 m, and at higher elevations the area as a whole is considered a sacred landscape. Religious beliefs may affect the ecology of these sacred areas, resulting in unique ecological characteristics of importance to conservation; recent studies have demonstrated that sacred areas can often play a major role in conservation. The goal of this study is to preliminarily analyze the vegetation of sacred areas in the Menri region using existing vegetation maps and a Geographical Information System (GIS) for remote assessment. Sacred sites are compared to random points in the landscape, in terms of: elevation, vegetation, and nearness to villages; species composition, diversity, and richness; and frequency of useful and endemic plant species. Detrended correspondence analysis (DCA) ordination reveals that sacred sites differ significantly in both useful species composition (p=0.034) and endemic species composition (p=0.045). Sacred sites are located at lower elevations, and closer to villages, than randomly selected, non-sacred sites (p< 0.0001), and have higher overall species richness (p=0.033) and diversity (p=0.042). In addition, the high-elevation (> 4000 m) areas of the mountain - a sacred landscape - are found to have significantly more endemics than low-elevation areas (p<0.0001). These findings represent an initial analysis of sacred sites and suggest that sacred sites in the Menri region may be ecologically and ethnobotanically unique.