Evaluation of solid polymeric organic materials for use in bioreactive sediment capping to stimulate the degradation of chlorinated aliphatic hydrocarbons

In situ bioreactive capping is a promising technology for mitigation of surface water contamination by discharging polluted groundwater. Organohalide respiration (OHR) of chlorinated ethenes in bioreactive caps can be stimulated through incorporation of solid polymeric organic materials (SPOMs) that provide a sustainable electron source for organohalide respiring bacteria. In this study, wood chips, hay, straw, tree bark and shrimp waste, were assessed for their long term applicability as an electron donor for OHR of cis-dichloroethene (cDCE) and vinyl chloride (VC) in sediment microcosms. The initial release of fermentation products, such as acetate, propionate and butyrate led to the onset of extensive methane production especially in microcosms amended with shrimp waste, straw and hay, while no considerable stimulation of VC dechlorination was obtained in any of the SPOM amended microcosms. However, in the longer term, short chain fatty acids accumulation decreased as well as methanogenesis, whereas high dechlorination rates of VC and cDCE were established with concomitant increase of Dehalococcoides mccartyi and vcrA and bvcA gene numbers both in the sediment and on the SPOMs. A numeric simulation indicated that a capping layer of 40 cm with hay, straw, tree bark or shrimp waste is suffice to reduce the groundwater VC concentration below the threshold level of 5 μg/l before discharging into the Zenne River, Belgium. Of all SPOMs, the persistent colonization of tree bark by D. mccartyi combined with the lowest stimulation of methanogenesis singled out tree bark as a long-term electron donor for OHR of cDCE/VC in bioreactive caps.     

Nanoparticles of Selenium as Species with Stronger Physiological Effects in Sheep in Comparison with Sodium Selenite

The present study was designed to compare the effects of nano red selenium and sodium selenite on the antioxidative activities of neutrophils and the hematological parameters in sheep. Fifteen sheep were randomly allocated into three groups. Groups 1 and 2 received selenium nanoparticles orally at 1 mg/kg and sodium selenite at 1 mg Se/kg for 10 consecutive days; group 3 served as the control. To assess the degrees of oxidative stress and of lipid peroxidation of the cellular membranes, the levels of thiobarbituric acid reactive substances (TBARS) were determined in serum samples that were collected at different supplementation intervals, i.e., after 0, 10, 20, and 30 days. In addition, hematological parameters in the serum samples were measured by routine procedures. It was found that TBARS levels in groups 1 and 2 were significantly higher on days 20 and 30 compared to the basal level on day 0. It was also found that on day 30, the TBARS activities in both treated groups were significantly higher than those of the controls (P < 0.05). These findings may explain the seemingly paradoxical effects of supplemental selenium on the indicators of oxidative stress, as the levels of TBARS were generally expected to decrease in the presence of selenium. There were no significant differences between the PCV and RBC values in the three groups. The white blood cell count (WBC) in group 1 showed a significant increase on days 20 and 30 in comparison with the control group. However, in group 2, there was a significant increase of the WBC value just on day 20 in comparison with the control group. Also, there were significant increases of the neutrophil counts and significant decreases of the lymphocyte counts on day 10 in group 1, in comparison with those in group 2 and controls, and on days 20 and 30 in groups 1 and 2 in comparison with those in the control group.     

Distribution frequency of pathogenic bacteria isolated from cutaneus leishmaniasis lesions

Cutaneous leishmaniasis (CL) is a parasitic disease characterized by single or multiple ulcerations. Secondary bacterial infections are one of the complications that can increase the tissue destruction and the resulting scar. To better determine the incidence of real secondary bacterial infections in CL, we designed the current study. This was a cross-sectional study performed in Skin Diseases and Leishmaniasis Research Centre, Isfahan, Iran. A total of 1,255 patients with confirmed CL enrolled in the study. Sterile swaps were achieved for ulcer exudates and scraping was used for non-ulcerated lesions. All samples were transferred to tryptic soy broth medium. After 24 hr of incubation at 37 degrees C they were transferred to eosin methylene blue agar (EMB) and blood agar. Laboratory tests were used to determine the species of bacteria. Among 1,255 confirmed CL patients, 274 (21.8%) had positive cultures for secondary bacterial infections. The bacteria isolated from the lesions were Staphylococcus aureus in 190 cases (69.3%), coagulase negative Staphylococcus in 63 cases (23.0%), E. coli in 10 cases (3.6%), Proteus sp. in 6 cases (2.2%), and Klebsiella sp. in 5 cases (1.9%). The results show that the overall incidence of secondary bacterial infections in the lesions of CL was 21.8%, considerably high. The incidence of secondary bacterial infections was significantly higher in ulcerated lesions compared with non-ulcerated lesions.     

Plasma membrane temperature gradients and multiple cell permeabilization induced by low peak power density femtosecond lasers

Calculations indicate that selectively heating the extracellular media induces membrane temperature gradients that combine with electric fields and a temperature-induced reduction in the electropermeabilization threshold to potentially facilitate exogenous molecular delivery. Experiments by a wide-field, pulsed femtosecond laser with peak power density far below typical single cell optical delivery systems confirmed this hypothesis. Operating this laser in continuous wave mode at the same average power permeabilized many fewer cells, suggesting that bulk heating alone is insufficient and temperature gradients are crucial for permeabilization. This work suggests promising opportunities for a high throughput, low cost, contactless method for laser mediated exogenous molecule delivery without the complex optics of typical single cell optoinjection, for potential integration into microscope imaging and microfluidic systems.     

Novel amides of 1,1‐bis‐(carboxymethylthio)‐1‐arylethanes: Synthesis,characterization, acetylcholinesterase,butyrylcholinesterase, and carbonic anhydrase inhibitory properties

The thiolation reaction was carried out in a benzene solution at 80°C and p‐substituted ketones and mercaptoacetic acid in a molar ratio (1:4) of in the presence of a catalytic amount of toluene sulfonic acids. The enzyme inhibition activities of the novel amides of 1,1‐bis‐(carboxymethylthio)‐1‐arylethanes derivatives were investigated. These novel amides of 1,1‐bis‐(carboxymethylthio)‐1‐arylethanes derivatives showed good inhibitory action against acetylcholinesterase (AChE) butyrylcholinesterase (BChE), and human carbonic anhydrase I and II isoforms (hCA I and II). AChE inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. Many clinically established drugs are carbonic anhydrase inhibitors, and it is highly anticipated that many more will eventually find their way into the market. The novel synthesized compounds inhibited AChE and BChE with K_i values in the range of 0.64–1.47 nM and 9.11–48.12 nM, respectively. On the other hand, hCA I and II were effectively inhibited by these compounds, with K_i values between 63.27–132.34 and of 29.63–127.31 nM, respectively.     

A unique epigenetic signature is associated with active DNA replication loci in human embryonic stem cells

The cellular epigenetic landscape changes as pluripotent stem cells differentiate to somatic cells or when differentiated cells transform to a cancerous state. These epigenetic changes are commonly correlated with differences in gene expression. Whether active DNA replication is also associated with distinct chromatin environments in these developmentally and phenotypically diverse cell types has not been known. Here, we used BrdU-seq to map active DNA replication loci in human embryonic stem cells (hESCs), normal primary fibroblasts and a cancer cell line, and correlated these maps to the epigenome. In all cell lines, the majority of BrdU peaks were enriched in euchromatin and at DNA repetitive elements, especially at microsatellite repeats, and coincided with previously determined replication origins. The most prominent BrdU peaks were shared between all cells but a sizable fraction of the peaks were specific to each cell type and associated with cell type-specific genes. Surprisingly, the BrdU peaks that were common to all cell lines were associated with H3K18ac, H3K56ac, and H4K20me1 histone marks only in hESCs but not in normal fibroblasts or cancer cells. Depletion of the histone acetyltransferases for H3K18 and H3K56 dramatically decreased the number and intensity of BrdU peaks in hESCs. Our data reveal a unique epigenetic signature that distinguishes active replication loci in hESCs from normal somatic or malignant cells.     

Effect of thymoquinone and Nigella sativa seeds oil on lipid peroxidation level during global cerebral ischemia-reperfusion injury in rat hippocampus

It has been previously reported that Nigella sativa oil (NSO) and thymoquinone (TQ), active constituent of N. sativa seeds oil, may prevent oxidative injury in various models. Therefore, we considered the possible effect of TQ and NSO on lipid peroxidation level following cerebral ischemia-reperfusion injury (IRI) in rat hippocampus. Male NMRI rats were divided into nine groups, namely, sham, control, ischemia and ischemia treated with NSO or TQ. TQ (2.5, 5 and 10 mg/kg), NSO (0.048, 0.192 and 0.384 mg/kg), phenytoin (50 mg/kg, as positive control) and saline (10 ml/kg, as negative control) were injected intraperitoneally immediately after reperfusion and the administration was continued every 24h for 72 h after induction of ischemia. The transient global cerebral ischemia was induced using four-vessel-occlusion method for 20 min. Lipid peroxidation level in hippocampus portion was measured as malondialdehyde (MDA) based on its reaction with thiobarbituric acid (TBA) following ischemic insult. The transient global cerebral ischemia induced a significant increase in TBA reactive substances (TBARS) level (p<0.001), in comparison with sham-operated animal. Pretreatment with TQ and NSO were resulted a significant decrease in MDA level as compared with ischemic group (66.9+/-1.5 vs. 297+/-2.5 nmol/g tissue for TQ, 10 mg/kg; p<0.001 and 153.5+/-1.3 nmol/g tissue for NSO, 0.384 mg/kg; p<0.001). Using a reversed-phase HPLC system, the amount of TQ in NSO was also quantified and was 0.58% w/w. These results suggest that TQ and NSO may have protective effects on lipid peroxidation process during IRI in rat hippocampus.