High Abundance of Thaumarchaeota Found in Deep Metamorphic Subsurface in Eastern China.

Members of the Thaumarchaeota phylum play a key role in nitrogen cycling and are prevalent in a variety of environments including soil, sediment, and seawater. However, few studies have shown the presence of Thaumarchaeota in the terrestrial deep subsurface. Using high-throughput 16S rRNA gene sequencing, this study presents evidence for the high relative abundance of Thaumarchaeota in a biofilm sample collected from the well of Chinese Continental Scientific Drilling at a depth of 2000 m. Phylogenetic analysis showed a close relationship of these thaumarchaeotal sequences with known ammonia-oxidizing archaea (AOA) isolates, suggesting the presence of AOA in the deep metamorphic environment of eastern China which is believed to be oxic. Based on fluid geochemistry and FAProTax functional prediction, a pathway of nitrogen cycling is proposed. Firstly, heterotrophic nitrogen fixation is executed by diazotrophic bacteria coupled with methane oxidation. Then, ammonia is oxidized to nitrite by AOA, and nitrite is further oxidized to nitrate by bacteria within the phylum Nitrospirae. Denitrification and anaerobic ammonia oxidation occur slowly, leading to nitrate accumulation in the subsurface. With respect to biogeochemistry, the reaction between downward diffusing O2 and upward diffusing CH4 potentially fuels the ecosystem with a high relative abundance of Thaumarchaeota.

Construction of a reconfigurable DNA nanocage for encapsulating a TMV disk.

A new reconfigurable DNA nanocage based on a DNA origami method has been constructed to capture a tobacco mosaic virus (TMV) disk. We used a hairpin to control the transformation of the nanocage and a strand of TMV RNA to attract the TMV disk. Our design could inspire new DNA-protein complex designs.

Engineer chimeric Cas9 to expand PAM recognition based on evolutionary information.

Although Cas9 nucleases are remarkably diverse in microorganisms, the range of genomic sequences targetable by a CRISPR/Cas9 system is restricted by the requirement of a short protospacer adjacent motif (PAM) at the target site. Here, we generate a group of chimeric Cas9 (cCas9) variants by replacing the key region in the PAM interaction (PI) domain of Staphylococcus aureus Cas9 (SaCas9) with the corresponding region in a panel of SaCas9 orthologs. By using a functional assay at target sites with different nucleotide recombinations at PAM position 3-6, we identify several cCas9 variants with expanded recognition capability at NNVRRN, NNVACT, NNVATG, NNVATT, NNVGCT, NNVGTG, and NNVGTT PAM sequences. In summary, we provide a panel of cCas9 variants accessible up to 1/4 of all the possible genomic targets in mammalian cells.

Neuroprotective effects of Coptis chinensis Franch polysaccharide on amyloid-beta (Aß)-induced toxicity in a transgenic Caenorhabditis elegans model of Alzheimer's disease (AD).

This study aims to investigate the neuroprotective effects of Coptis chinensis Franch polysaccharide (CCP) on Aß1-42 transgenic CL4176 Caenorhabditis elegans, as well as its mechanism of action. The results in life span experiment showed that CCP could significantly increase the lifespan of C. elegans and the effect is in the descending order of 100mg/L>500mg/L>200mg/L. The behavioral experiments also demonstrated that CCP at the concentration of 100mg/L could delay the paralysis rate of C. elegans, which was significantly different from the control group. In terms of Aß toxicity in C. elegans, morphological observation using Thioflavin S staining method indicated that the deposition of Aß protein in the head area of the untreated C. elegans was much more than those in the CCP (100mg/L)-treated CL4176. In line with this finding, fluorogenic quantitative real-time PCR confirmed that the transcriptional levels of HSP16.2 (Y46H3A.D) and HSP16.41 (Y46H3A.E) in C. elegans was 21 times and 79 times higher than those in untreated control. Thus, these data demonstrate that CCP could reduce Aß-induced toxicity by delaying the aging, decreasing the rate of paralysis, inhibiting the deposition of Aß, and increasing the expression levels of HSP genes in transgenic C. elegans.

[The construction and application of a novel apparatus for detecting oxygen consumption of mice under normobaric hypoxia].

OBJECTIVE: To establish a method for real-time recording the oxygen consumption of mice under normobaric hypoxia. METHODS: The experimental apparatus was made up of animal container, filling water control system, electronic balance, hose, a computer with weight recording software, etc. The working principle was that the oxygen consumed by animal was replaced by water filling which was controlled by the pneumatic and hydraulic actuator. The water was weighted by an electronic balance and the weight signal was recorded into excel file at the same time. The accuracy and precision of the apparatus were detected by a 10 ml syringe. The oxygen consumption characteristics of 6 acute repetitive hypoxia mice and 6 normal mice were observed. RESULTS: The P value for the paired t test was 1 and the CV value was 4%. The survival time and total oxygen consumption of acute repetitive hypoxia mice were both significantly increased compared to normal mice (P < 0.05), which were (58.8 +/- 6.8) min and (46.0 +/- 8.7) min respectively for the survival time and (85.1 +/- 8.5) ml and (73.6 +/- 5.4) ml respectively for total oxygen consumption. CONCLUSION: The hypoxia tolerance of the acute repetitive hypoxia mice can significantly improved by taking more oxygen in the animal cabin. The accuracy and precision of the apparatus are high and it can be used for the determination of oxygen consumption in hypoxia research.

[Choline promotes angiogenesis in chick embryo chorioallantoic membrane].

OBJECTIVE: To investigate choline promoting angiogenesis on chick embryo chorioallantoic membrane (CAM). METHODS: CAM model was prepared, the choline chloride, human vascular endothelial growth factor (hVEGF) and normal saline were added respectively onto the carrier on the CAM, the state of angiogenesis was observed and the number of new blood vessels was counted. RESULTS: Choline chloride was tested at the concentrations of 0.5 nmol/L - 1 mmol/L in this experiment, when its concentrations were increased to 0.01 micromol/L - 1 000 micromol/L, it could stimulate angiogenesis, the minimum effective concentration was tested as 0.01 micromol/L, and its effect for promoting the angiogenesis was equivalent to that of hVEGF, the potent stimulator for angiogenesis. CONCLUSION: The result shows that choline can promote angiogenesis in the chick embryo chorioallantoic membrane.