Viscoelastic features of adhesive setae of the tokay gecko (<Emphasis Type="Italic">Gekko gecko</Emphasis> L.)

Deformations of particular setae of adhesive toe pad of the tokay gecko were investigated by atomic-force microscopy. The effective elastic modulus of the investigated setae varying within 0.34–19 GPa, a pronounced hysteresis was observed during reversible bending of setae. The hysteresis-related energy losses may be as high as 98% of the total bending work. The pronounced viscous features of the setae contradict the hypothesis of dynamic self-cleaning of the gecko adhesive cover, according to which the setae are considered as absolutely elastic cantilever beams.     

Broiler chicken cecal microbiocenoses depending on mixed fodder

Molecular genetic techniques (NGS sequencing and quantitative PCR) were used to determine the composition of the cecal bacterial community of broiler chickens fed with different mixed fodder. The cecal microbiome exhibited taxonomic diversity, with both typical inhabitants of avian intestine belonging to the families Clostridiaceae, Eubacteriaceae, and Lactobacillaceae and to the phylum Bacteroidetes, and new unidentified taxa, as well as bacteria of the families Lachnospiraceae and Ruminococcaceae, which were previously considered restricted to the rumen microbiota. Contrary to traditional concepts, enterococci and bifidobacteria were among the minor components of the community, lactate-fermenting species were absent, and typical avian pathogens of the genus Staphylococcus were detected but seldom. Members of the family Suterellaceae and the genus Gallibacterium, which are responsible for avian respiratory infections, were also detected. Significant fluctuations of abundance and composition of microbial groups within the cecal community and of the parameters of broiler productivity were found to occur depending on the feed allowance. Cellulose content in the feed had the most pronounced effect on the composition and structure of bacterial communities. Decreased cellulose content resulted in a decrease of bacterial abundance by an order of magnitude and in increased ratios of members of the phylum Bacteroidetes and the family Clostridiaceae, which possess the enzymes degrading starch polysaccharides. Abundance of the normal inhabitants of avian intestine belonging to the genus Lactobacillus and the order Bacillales decreased, while the share of Escherichia and members of the family Sutterellaceae increased, including some species capable of causing dysbiotic changes in the avian intestine. No significant change in the abundance of cellulolytics of the families Ruminococcaceae, Lachnospiraceae, and Eubacteriaceae was observed.     

Precision breeding for RNAi suppression of a major 4-coumarate:coenzyme A ligase gene improves cell wall saccharification from field grown sugarcane

Sugarcane (Saccharum spp. hybrids) is a major feedstock for commercial bioethanol production. The recent integration of conversion technologies that utilize lignocellulosic sugarcane residues as well as sucrose from stem internodes has elevated bioethanol yields. RNAi suppression of lignin biosynthetic enzymes is a successful strategy to improve the saccharification of lignocellulosic biomass. 4-coumarate:coenzyme A ligase (4CL) is a key enzyme in the biosynthesis of phenylpropanoid metabolites, such as lignin and flavonoids. Identifying a major 4CL involved in lignin biosynthesis among multiple isoforms with functional divergence is key to manipulate lignin biosynthesis. In this study, two full length 4CL genes (Sh4CL1 and Sh4CL2) were isolated and characterized in sugarcane. Phylogenetic, expression and RNA interference (RNAi) analysis confirmed that Sh4CL1 is a major lignin biosynthetic gene. An intragenic precision breeding strategy may facilitate the regulatory approval of the genetically improved events and was used for RNAi suppression of Sh4CL1. Both, the RNAi inducing cassette and the expression cassette for the mutated ALS selection marker consisted entirely of DNA sequences from sugarcane or the sexually compatible species Sorghum bicolor. Field grown sugarcane with intragenic RNAi suppression of Sh4CL1 resulted in reduction of the total lignin content by up to 16.5?% along with altered monolignol ratios without reduction in biomass yield. Mature, field grown, intragenic sugarcane events displayed 52–76?% improved saccharification efficiency of lignocellulosic biomass compared to wild type (WT) controls. This demonstrates for the first time that an intragenic approach can add significant value to lignocellulosic feedstocks for biofuel and biochemical production.     

Short‐term calorie restriction ameliorates genomewide,age‐related alterations in DNA methylation

DNA methylation plays major roles in many biological processes, including aging, carcinogenesis, and development. Analyses of DNA methylation using next‐generation sequencing offer a new way to profile and compare methylomes across the genome in the context of aging. We explored genomewide DNA methylation and the effects of short‐term calorie restriction (CR) on the methylome of aged rat kidney. Whole‐genome methylation of kidney in young (6 months old), old (25 months old), and OCR (old with 4‐week, short‐term CR) rats was analyzed by methylated DNA immunoprecipitation and next‐generation sequencing (MeDIP‐Seq). CpG islands and repetitive regions were hypomethylated, but 5′‐UTR, exon, and 3′‐UTR hypermethylated in old and OCR rats. The methylation in the promoter and intron regions was decreased in old rats, but increased in OCR rats. Pathway enrichment analysis showed that the hypermethylated promoters in old rats were associated with degenerative phenotypes such as cancer and diabetes. The hypomethylated promoters in old rats related significantly to the chemokine signaling pathway. However, the pathways significantly enriched in old rats were not observed from the differentially methylated promoters in OCR rats. Thus, these findings suggest that short‐term CR could partially ameliorate age‐related methylation changes in promoters in old rats. From the epigenomic data, we propose that the hypermethylation found in the promoter regions of disease‐related genes during aging may indicate increases in susceptibility to age‐related diseases. Therefore, the CR‐induced epigenetic changes that ameliorate age‐dependent aberrant methylation may be important to CR's health‐ and life‐prolonging effects.     

Single‐Walled Carbon Nanotubes in Emerging Solar Cells: Synthesis and Electrode Applications

Emerging solar cells, namely, organic solar cells and perovskite solar cells, are the thin‐film photovoltaics that have light to electricity conversion efficiencies close to that of silicon solar cells while possessing advantages in having additional functionalities, facile‐processability, and low fabrication cost. To maximize these advantages, the electrode components must be replaced by materials that are more flexible and cost‐effective. Researchers around the globe have been looking for the new electrodes that meet these requirements. Among many candidates, single‐walled carbon nanotubes have demonstrated their feasibility as the new alternative to conventional electrodes, such as indium tin oxide and metals. This review discusses various growth methods of single‐walled carbon nanotubes and their electrode applications in thin‐film photovoltaics.     

Optimal Interfacial Engineering with Different Length of Alkylammonium Halide for Efficient and Stable Perovskite Solar Cells

Recently, two‐dimensional (2D) structure on three‐dimensional (3D) perovskites (graded 2D/3D) has been reported to be effective in significantly improving both efficiency and stability. However, the electrical properties of the 2D structure as a passivation layer on the 3D perovskite thin film and resistance to the penetration of moisture may vary depending on the length of the alkyl chain. In addition, the surface defects of the 2D itself on the 3D layer may also be affected by the correlation between the 2D structure and the hole conductive material. Therefore, systematic interfacial study with the alkyl chain length of long‐chained alkylammonium iodide forming a 2D structure is necessary. Herein, the 2D interfacial layers formed are compared with butylammonium iodide (BAI), octylammonium iodide (OAI), and dodecylammonium iodide (DAI) iodide on a 3D (FAPbI₃)_0.95(MAPbBr₃)_0.05 perovskite thin film in terms of the PCE and humidity stability. As the length of the alkyl chain increased from BA to OA to DA, the electron‐blocking ability and humidity resistance increase significantly, but the difference between OA and DA is not large. The PSC post‐treated with OAI has slightly higher PCE than those treated with BAI and DAI, achieving a certified stabilized efficiency of 22.9%.     

Detection of dental plaque and its potential pathogenicity using quantitative light‐induced fluorescence

Quantitative light‐induced fluorescence (QLF) technology can detect some dental plaque as red fluorescence. This in vivo study aimed to identify the microbial characteristics of red fluorescent (RF) dental plaque using 16S rRNA gene sequencing and evaluate the correlations between RF plaque and the clinical symptoms of dental diseases. Paired supragingival plaque samples collected from each 10 subjects and consisted of RF and non‐RF dental plaques as observed by QLF technology using a 405 nm blue light source for excitation. The characteristics of the bacterial communities in the RF and non‐RF plaque samples were compared by sequencing analysis. An increase in microbial diversity was observed in RF plaque compared with the non‐RF plaque. There were significant differences in the community compositions between the 2 types of dental plaque. Periodontopathic bacteria were significantly more abundant in the RF plaque than non‐RF plaque. The fluorescence intensity of RF plaque was significantly related to the proportion of the periodontopathic bacterial community and the presence of gingival inflammation. In conclusion, the plaque red fluorescence is associated with changes in the microbial composition and enrichment of periodontopathic pathogens, which suggests that RF plaque detected by QLF technology could be used as a risk indicator for gingival inflammation.      

Proteomic analysis of glutamate-induced toxicity in HT22 cells

In the present study, we have investigated the proteome changes associated with glutamate-induced HT22 cell death, a model system to study oxidative stress-mediated toxicity. Among a number of HT22 proteins exhibiting altered expression, several molecular chaperones demonstrated substantial changes. For example, the levels of Hsp90 and Hsp70 decreased as cell death progressed whereas that of Hsp60 increased dramatically. Interestingly, cytosolic Hsp60 increased more prominently than mitochondrial Hsp60. Concomitantly, the accumulation of poly-ubiquitylated proteins and differential regulation of the peptidase activities and the subunits of 26S proteasomes were observed in glutamate-treated HT22 cells. Our findings that the molecular chaperones and the ubiquitin-proteasome system undergo changes during glutamate-induced HT22 cell death may suggest the importance of a protein quality control system in oxidative damage-mediated toxicity.