Cytotoxicity and Transcriptomic Analysis of Silver Nanoparticles in Mouse Embryonic Fibroblast Cells.

The rapid development of nanotechnology has led to the use of silver nanoparticles (AgNPs) in biomedical applications, including antibacterial, antiviral, anti-inflammatory, and anticancer therapies. The molecular mechanism of AgNPs-induced cytotoxicity has not been studied thoroughly using a combination of cellular assays and RNA sequencing (RNA-Seq) analysis. In this study, we prepared AgNPs using myricetin, an anti-oxidant polyphenol, and studied their effects on NIH3T3 mouse embryonic fibroblasts as an in vitro model system to explore the potential biomedical applications of AgNPs. AgNPs induced loss of cell viability and cell proliferation in a dose-dependent manner, as evident by increased leakage of lactate dehydrogenase (LDH) from cells. Reactive oxygen species (ROS) were a potential source of cytotoxicity. AgNPs also incrementally increased oxidative stress and the level of malondialdehyde, depleted glutathione and superoxide dismutase, reduced mitochondrial membrane potential and adenosine triphosphate (ATP), and caused DNA damage by increasing the level of 8-hydroxy-2'-deoxyguanosine and the expressions of the p53 and p21 genes in NIH3T3 cells. Thus, activation of oxidative stress may be crucial for NIH3T3 cytotoxicity. Interestingly, gene ontology (GO) term analysis revealed alterations in epigenetics-related biological processes including nucleosome assembly and DNA methylation due to AgNPs exposure. This study is the first demonstration that AgNPs can alter bulk histone gene expression. Therefore, our genome-scale study suggests that the apoptosis observed in NIH3T3 cells treated with AgNPs is mediated by the repression of genes required for cell survival and the aberrant enhancement of nucleosome assembly components to induce apoptosis.

High-throughput nucleotide sequence analysis of diverse bacterial communities in leachates of decomposing pig carcasses.

The leachate generated by the decomposition of animal carcass has been implicated as an environmental contaminant surrounding the burial site. High-throughput nucleotide sequencing was conducted to investigate the bacterial communities in leachates from the decomposition of pig carcasses. We acquired 51,230 reads from six different samples (1, 2, 3, 4, 6 and 14 week-old carcasses) and found that sequences representing the phylum Firmicutes predominated. The diversity of bacterial 16S rRNA gene sequences in the leachate was the highest at 6 weeks, in contrast to those at 2 and 14 weeks. The relative abundance of Firmicutes was reduced, while the proportion of Bacteroidetes and Proteobacteria increased from 3-6 weeks. The representation of phyla was restored after 14 weeks. However, the community structures between the samples taken at 1-2 and 14 weeks differed at the bacterial classification level. The trend in pH was similar to the changes seen in bacterial communities, indicating that the pH of the leachate could be related to the shift in the microbial community. The results indicate that the composition of bacterial communities in leachates of decomposing pig carcasses shifted continuously during the study period and might be influenced by the burial site.

Two-stage cultivation strategy for the improvement of pigment productivity from high-density heterotrophic algal cultures.

Herein, a two-stage cultivation process was devised to overcome low pigment content of algal biomass grown in heterotrophy. Post-treatment conditions (i.e., light intensity, temperature, pH and salinity) were initially tested for dense heterotrophically-grown Chlorella sp. HS2 cultures in a multi-channel photobioreactor (mcPBR), and the results clearly indicated the influence of each abiotic factor on algal pigment production. Subsequently, the optimal post-treatment conditions (i.e., 455 µmol m-2 s-1, 34.8℃, pH 8.23 and 0.7% (w/v) salinity), in which highest accumulation of algal pigments is expected, were identified using Response Surface Methodology (RSM). Compared to the control cultures grown in mixotrophy for the same duration of entire two-stage process, the results indicated a significantly higher pigment productivity (i.e., 167.5 mg L-1 day-1) in a 5-L fermenter following the post-treatment at optimal conditions. Collectively, these results suggest that the post-treatment of heterotrophic cultures can be successfully deployed to harness the nascent algae-based bioeconomy.

Epigenetic priming by Dot1l in lymphatic endothelial progenitors ensures normal lymphatic development and function.

Proper functioning of the lymphatic system is required for normal immune responses, fluid balance, and lipid reabsorption. Multiple regulatory mechanisms are employed to ensure the correct formation and function of lymphatic vessels; however, the epigenetic modulators and mechanisms involved in this process are poorly understood. Here, we assess the regulatory role of mouse Dot1l, a histone H3 lysine (K) 79 (H3K79) methyltransferase, in lymphatic formation. Genetic ablation of Dot1l in Tie2(+) endothelial cells (ECs), but not in Lyve1(+) or Prox1(+) lymphatic endothelial cells (LECs) or Vav1(+) definitive hematopoietic stem cells, leads to catastrophic lymphatic anomalies, including skin edema, blood-lymphatic mixing, and underdeveloped lymphatic valves and vessels in multiple organs. Remarkably, targeted Dot1l loss in Tie2(+) ECs leads to fully penetrant lymphatic aplasia, whereas Dot1l overexpression in the same cells results in partially hyperplastic lymphatics in the mesentery. Genetic studies reveal that Dot1l functions in c-Kit(+) hemogenic ECs during mesenteric lymphatic formation. Mechanistically, inactivation of Dot1l causes a reduction of both H3K79me2 levels and the expression of genes important for LEC development and function. Thus, our study establishes that Dot1l-mediated epigenetic priming and transcriptional regulation in LEC progenitors safeguard the proper lymphatic development and functioning of lymphatic vessels.

Nutrient status and phytotoxicity analysis of goat manure discharged from farms in South Korea.

The present study evaluated the phytotoxicity effect of goat manure (GM) collected from six different regions in South Korea, namely, Chupungnyeong (T1), Hoengseong (T2), Goesan (T3), Sancheong (T4), Jangsu (T5) and Namwon (T6). Phytotoxicity was assessed by means of the analysis of germination index (GI), relative seed germination (RSG), relative root elongation (RRE) and vigor index (VI) using five commercial crop varieties, namely, sesame (Sesamum indicum L.), chrysanthemum (Chrysanthemum indicum L.), carrot (Daucus carota), radish (Raphanus sativus) and cabbage (Brassica rapa). Physico-chemical parameter values were recorded at appreciable levels in all GM extracts. The effect of seedling growth was significantly different (p ≤ .05) due to the variability of nutrient content and phytotoxic effect of the extracts on the different crop seeds. Of the extracts, Goesan (T3) and Sancheong (T4) recorded the best results in the range of GI (%) (54.1-128.8) and VI (930.7-1044) and GI (%) (70.1-167.3) and VI (609.2-3034), respectively, and also showed no inhibitory effect in any of the crop seeds. Overall results also revealed that radish crops showed excellent and non-phytotoxic results in all manure extracts compared to the other crops.

Power-constrained contrast enhancement algorithm using multiscale retinex for OLED display.

This paper presents a power-constrained contrast enhancement algorithm for organic light-emitting diode display based on multiscale retinex (MSR). In general, MSR, which is the key component of the proposed algorithm, consists of power controllable log operation and subbandwise gain control. First, we decompose an input image to MSRs of different sub-bands, and compute a proper gain for each MSR. Second, we apply a coarse-to-fine power control mechanism, which recomputes the MSRs and gains. This step iterates until the target power saving is accurately accomplished. With video sequences, the contrast levels of adjacent images are determined consistently using temporal coherence in order to avoid flickering artifacts. Finally, we present several optimization skills for real-time processing. Experimental results show that the proposed algorithm provides better visual quality than previous methods, and a consistent power-saving ratio without flickering artifacts, even for video sequences.

Deodorization of pig slurry and characterization of bacterial diversity using 16S rDNA sequence analysis.

The concentration of major odor-causing compounds including phenols, indoles, short-chain fatty acids (SCFAs) and branched chain fatty acids (BCFAs) in response to the addition of powdered horse radish (PHR) and spent mushroom compost (SMC) was compared with control non-treated slurry (CNS) samples. A total of 97,465 rDNAs sequence reads were generated from three different samples (CNS, n = 2; PHR, n = 3; SMC, n = 3) using bar-coded pyrosequencing. The number of operational taxonomic units (OTUs) was lower in the PHR slurry compared with the other samples. A total of 11 phyla were observed in the slurry samples, while the phylogenetic analysis revealed that the slurry microbiome predominantly comprised members of the Bacteroidetes, Firmicutes, and Proteobacteria phyla. The rarefaction analysis showed the bacterial species richness varied among the treated samples. Overall, at the OTU level, 2,558 individual genera were classified, 276 genera were found among the three samples, and 1,832 additional genera were identified in the individual samples. A principal component analysis revealed the differences in microbial communities among the CNS, PHR, and SMC pig slurries. Correlation of the bacterial community structure with the Kyoto Encyclopedia of Genes and Genomes (KEGG) predicted pathways showed that the treatments altered the metabolic capabilities of the slurry microbiota. Overall, these results demonstrated that the PHR and S MC treatments significantly reduced the malodor compounds in pig slurry (P < 0.05).