In Vivo Study of Spherical Gold Nanoparticles: Inflammatory Effects and Distribution in Mice

Objectives

Gold nanoparticles (AuNPs) of 21 nm have been previously well characterized in vitro for their capacity to target macrophages via active uptake. However, the short-term impact of such AuNPs on physiological systems, in particular resident macrophages located in fat tissue in vivo, is largely unknown. This project investigated the distribution, organ toxicity and changes in inflammatory cytokines within the adipose tissue after mice were exposed to AuNPs.

Methods

Male C57BL/6 mice were injected intraperitoneally (IP) with a single dose of AuNPs (7.85 μg AuNPs/g). Body weight and energy intake were recorded daily. Tissues were collected at 1 h, 24 h and 72 h post-injection to test for organ toxicity. AuNP distribution was examined using electron microscopy. Proinflammatory cytokine expression and macrophage number within the abdominal fat pad were determined using real-time PCR.

Results

At 72 hours post AuNP injection, daily energy intake and body weight were found to be similar between Control and AuNP treated mice. However, fat mass was significantly smaller in AuNP-treated mice. Following IP injection, AuNPs rapidly accumulated within the abdominal fat tissue and some were seen in the liver. A reduction in TNFα and IL-6 mRNA levels in the fat were observed from 1 h to 72 h post AuNP injection, with no observable changes in macrophage number. There was no detectable toxicity to vital organs (liver and kidney).

Conclusion

Our 21 nm spherical AuNPs caused no measurable organ or cell toxicity in mice, but were correlated with significant fat loss and inhibition of inflammatory effects. With the growing incidence of obesity and obesity-related diseases, our findings offer a new avenue for the potential development of gold nanoparticles as a therapeutic agent in the treatment of such disorders.     

Screening of phytotoxicity of Alternaria macrospora MKP1 against Parthenium hysterophorus L.

Parthenium hysterophorus L. an exotic, pernicious weed is considered as one of the most troublesome weeds for agricultural sector by virtue of its high ecological amplitude and adaptability. Microbes and their by-products are now proved to be a worthy alternative to toxic chemicals used for weed management. Alternaria macrospora MKPI was isolated from the parthenium leaves infected with leaf blight and found pathogenic to the weed. The herbicidal potential of cell free culture filtrate of A. macrospora MKP1 has been tested against parthenium by employing detached leaf bioassay and seed germination bioassay and a significant damage was exhibited by the cultural filtrate of pathogen to the parthenium leaves and seeds.     

Characterization of a novel xylanase from Armillaria gemina and its immobilization onto SiO2 nanoparticles

Enhanced catalytic activities of different lignocellulases were obtained from Armillaria gemina under statistically optimized parameters using a jar fermenter. This strain showed maximum xylanase, endoglucanase, cellobiohydrolase, and β-glucosidase activities of 1,270, 146, 34, and 15 U mL^?1, respectively. Purified A. gemina xylanase (AgXyl) has the highest catalytic efficiency (k _cat/K _m?=?1,440 mg?mL^?1?s^?1) ever reported for any fungal xylanase, highlighting the significance of the current study. We covalently immobilized the crude xylanase preparation onto functionalized silicon oxide nanoparticles, achieving 117 % immobilization efficiency. Further immobilization caused a shift in the optimal pH and temperature, along with a fourfold improvement in the half-life of crude AgXyl. Immobilized AgXyl gave 37.8 % higher production of xylooligosaccharides compared to free enzyme. After 17 cycles, the immobilized enzyme retained 92 % of the original activity, demonstrating its potential for the synthesis of xylooligosaccharides in industrial applications.     

Multiple Single-Cell Genomes Provide Insight into Functions of Uncultured Deltaproteobacteria in the Human Oral Cavity

Despite a long history of investigation, many bacteria associated with the human oral cavity have yet to be cultured. Studies that correlate the presence or abundance of uncultured species with oral health or disease highlight the importance of these community members. Thus, we sequenced several single-cell genomic amplicons from Desulfobulbus and Desulfovibrio (class Deltaproteobacteria) to better understand their function within the human oral community and their association with periodontitis, as well as other systemic diseases. Genomic data from oral Desulfobulbus and Desulfovibrio species were compared to other available deltaproteobacterial genomes, including from a subset of host-associated species. While both groups share a large number of genes with other environmental Deltaproteobacteria genomes, they encode a wide array of unique genes that appear to function in survival in a host environment. Many of these genes are similar to virulence and host adaptation factors of known human pathogens, suggesting that the oral Deltaproteobacteria have the potential to play a role in the etiology of periodontal disease.     

Genetic and Epigenetic Variation across Genes Involved in Energy Metabolism and Mitochondria of Chinese Hamster Ovary Cell Lines

The increasingdemandfor biopharmaceutical products drives the search for efficient cell factories that are able to sustainably support rapid growth, high productivity, and product quality. As these depend on energy generation, here the genomic variation in nuclear genes associated with mitochondria and energy metabolism and the mitochondrial genome of 14 cell lines is investigated. The variants called enable reliable tracing of lineages. Unique sequence variations are observed in cell lines adapted to grow in protein‐free media, enriched in signaling pathways or mitogen‐activated protein kinase 3. High‐producing cell lines bear unique mutations in nicotinamide adenine dinucleotide (NADH) dehydrogenase (ND2 and ND4) and in peroxisomal acyl‐CoA synthetase (ACSL4), involved in lipid metabolism. As phenotypes are determined not only by functional mutations, but also by the exquisite regulation of expression patterns, it is not surprising that ≈50% of the genes investigated here are found to be differentially methylated and thus epigenetically controlled, enabling a clear distinction of high producers, and cells adapted to a minimal, glutamine (Gln)‐free medium. Similar pathways are enriched as those identified by genome variation. This strengthens the hypothesis that these phenomena act together to define cell behavior.     

Preparation, application and testing of permanent antibacterial and antiviral coatings

Protocols for the synthesis of the microbicidal polycation N,N-dodecyl,methyl-polyethylenimine and coating (painting) of glass slides with this polycation's butanol solution are described. Subsequently detailed are the procedures for validating that the resultant coated slides are essentially 100% lethal to the human bacterial pathogens, Staphylococcus aureus and Escherichia coli, as well as to two common strains of influenza virus. The time required to prepare and apply the cationic polymer and to test its microbicidal efficiency is conservatively estimated to be <4 weeks.     

No sitting on the fence: protecting wetlands from feral pig damage by exclusion fences requires effective fence maintenance

Feral pigs damage the significant ecological and cultural values of tropical Australian wetlands. Control measures such as culling, baiting, and trapping can reduce overall pig populations, but do not eliminate the substantial physical damage to wetlands that can occur from just a few individuals. Exclusion fences have been adopted as a potential technique to prevent damage to selected wetlands. To test the effectiveness of exclusion fences we measured the physical damage caused by pigs to multiple wetlands in the Archer River catchment of tropical northern Australia. Wetlands were fenced using a typical cattle exclusion fence, a specific pig exclusion fence or had no fence. Initial analyses of these fence treatments showed no significant difference in the intensity of physical pig damage to exposed wetland sediments and fringing vegetation. However, several of the pig exclusion fences were found to have been compromised. Reanalysis indicated wetlands with functioning pig exclusion fences had no physical pig damage and this was significantly less damage than in all other treatments. In contrast, wetlands with compromised pig exclusion fences had damage that was statistically equivalent to sites without fences or with cattle exclusion fences, but in individual cases had the worst damage recorded in any of the treatments. Compromised pig exclusion fencing of wetlands can thus be worse than having no fencing at all. This suggests that the successful prevention of pig damage to wetlands by exclusion fences requires ongoing and effective fence monitoring and maintenance regimes.