Microbial community responses reduce soil carbon loss in Tibetan alpine grasslands under short‐term warming

Changes in labile carbon (LC) pools and microbial communities are the primary factors controlling soil heterotrophic respiration (R_h) in warming experiments. Warming is expected to initially increase R_h but studies show this increase may not be continuous or sustained. Specifically, LC and soil microbiome have been shown to contribute to the effect of extended warming on R_h. However, their relative contribution is unclear and this gap in knowledge causes considerable uncertainty in the prediction of carbon cycle feedbacks to climate change. In this study, we used a two‐step incubation approach to reveal the relative contribution of LC limitation and soil microbial community responses in attenuating the effect that extended warming has on R_h. Soil samples from three Tibetan ecosystems—an alpine meadow (AM), alpine steppe (AS), and desert steppe (DS)—were exposed to a temperature gradient of 5–25°C. After an initial incubation period, soils were processed in one of two methods: (a) soils were sterilized then inoculated with parent soil microbes to assess the LC limitation effects, while controlling for microbial community responses; or (b) soil microbes from the incubations were used to inoculate sterilized parent soils to assess the microbial community effects, while controlling for LC limitation. We found both LC limitation and microbial community responses led to significant declines in R_h by 37% and 30%, respectively, but their relative contributions were ecosystem specific. LC limitation alone caused a greater R_h decrease for DS soils than AMs or ASs. Our study demonstrates that soil carbon loss due to R_h in Tibetan alpine soils—especially in copiotrophic soils—will be weakened by microbial community responses under short‐term warming.     

Design,synthesis and biological evaluation of novel human monoamine oxidase B inhibitors based on a fragment in an X-ray crystal structure

Herein we report our efforts of developing reversible selective hMAO-B inhibitors based on isatin, a fragment in an X-ray crystal structure. Five different scaffolds were designed and many compounds were synthesized. Among them, compound A3 demonstrated very high potency and isoform selectivity against hMAO-B, 11 and 13 times more potent (IC₅₀?=?3?nM) and 23.64 and 6.8 times more selective than the marked drugs, selegiline and safinamide. However, the endeavors to modify the polar 3-one group of isatin, that is in a hydrophobic environment in the binding site of hMAO-B, to small nonpolar hydrophobic groups did not bring about improved hMAO-B inhibitors, which may challenge our understanding of molecular interactions and molecular recognition in biological systems.     

Whole‐brain microcirculation detection after ischemic stroke based on swept‐source optical coherence tomography

The occurrence and development of ischemic stroke are closely related to cerebral blood flow. Real‐time monitoring of cerebral perfusion level is very useful for understanding the mechanisms of the disease. A wide field of view (FOV) is conducive to capturing lesions and observing the progression of the disease. In this paper, we attempt to monitor the whole‐brain microcirculation in middle cerebral artery occlusion (MCAO) rats over time using a wide FOV swept‐source OCT (SS‐OCT) system. A constrained image registration algorithm is used to remove motion artifacts that are prone to occur in a wide FOV angiography. During ischemia, cerebral perfusion levels in the left and right hemispheres, as well as in the whole brain were quantified and compared. Changes in the shape and location of blood vessels were also recorded. The results showed that the trend in cerebral perfusion levels of both hemispheres was highly consistent during MCAO, and the position of the blood vessels varied over time. This work will provide new insights of ischemic stroke and is helpful to assess the effectiveness of potential treatment strategies.      

Efficient Human Genome Editing Using SaCas9 Ribonucleoprotein Complexes

Genome editing using RNA‐guided nucleases in their ribonucleoprotein (RNP) form represents a promising strategy for gene modification and therapy because they are free of exogenous DNA integration and have reduced toxicity in vivo and ex vivo. However, genome editing by Cas9 nuclease from Staphylococcus aureus (SaCas9) has not been reported in its RNP form, which recognizes a longer protospacer adjacent motif (PAM), 5′‐NNGRRT‐3′, compared with Streptococcus pyogenes Cas9 (SpCas9) of 5′‐NGG‐3′ PAM. Here, SaCas9‐RNP‐mediated genome editing is reported in human cells. The SaCas9‐RNP displayed efficient genome editing activities of enhanced green fluorescent protein (EGFP) coding gene as well as three endogenous genes (OPA1, RS1, and VEGFA). Further, SaCas9‐RNP is successfully implemented to correct a pathogenic RS1 mutation for X‐linked juvenile retinoschisis. It is also shown that off‐target effects triggered by SaCas9‐RNP are undetectable by targeted deep sequencing. Collectively, this study demonstrates the potential of SaCas9‐RNP‐mediated genome editing in human cells, which could facilitate genome‐editing‐based therapy.     

Grazing intensity enhances spatial aggregation of dominant species in a desert steppe

Understanding how grazing activity drives plant community structure or the distribution of specific species in a community remains a major challenge in community ecology. The patchiness or spatial aggregation of specific species can be quantified by analyzing their relative coordinates in the community. Using variance and geostatistical analysis methods, we examined the quantitative characteristics and spatial distribution of Stipa breviflora in a desert steppe in northern China under four different grazing intensities (no grazing, NG, light grazing, LG, moderate grazing, MG, and heavy grazing, HG) at three small spatial scales (10 × 10 cm, 20 × 20 cm, 25 × 25 cm). We found that grazing significantly increased cover, density, and proportion in standing crop of S. breviflora, but decreased height. The spatial distribution of S. breviflora was strongly dependent upon the sampling unit and grazing intensity. The patchiness of S. breviflora reduced with sampling scale, and spatial distribution of S. breviflora was mainly determined by structural factors. The intact clusters of S. breviflora were more fragmented with increasing grazing intensity and offspring clusters spread out from the center of the parent plant. These findings suggest that spatial aggregation can enhance the ability of S. breviflora to tolerate grazing and that smaller isolated clusters are beneficial to the survival of this dominant species under heavy grazing.     

Expert consensus on organizing the multidisciplinary team (MDT) diagnosis and treatment of hepato-pancreato-biliary diseases in China

Science China Life Sciences -     

Improved genome assembly of Chinese shrimp (Fenneropenaeus chinensis) suggests adaptation to the environment during evolution and domestication

A high-quality reference genome is necessary to determine the molecular mechanisms underlying important biological phenomena; therefore, in the present study, a chromosome-level genome assembly of the Chinese shrimp Fenneropenaeus chinensis was performed. Muscle of a male shrimp was sequenced using PacBio platform, and assembled by Hi-C technology. The assembled F. chinensis genome was 1.47 Gb with contig N50 of 472.84 Kb, including 57.73% repetitive sequences, and was anchored to 43 pseudochromosomes, with scaffold N50 of 36.87 Mb. In total, 25,026 protein-coding genes were predicted. The genome size of F. chinensis showed significant contraction in comparison with that of other penaeid species, which is likely related to migration observed in this species. However, the F. chinensis genome included several expanded gene families related to cellular processes and metabolic processes, and the contracted gene families were associated with virus infection process. The findings signify the adaptation of F. chinensis to the selection pressure of migration and cold environment. Furthermore, the selection signature analysis identified genes associated with metabolism, phototransduction, and nervous system in cultured shrimps when compared with wild population, indicating targeted, artificial selection of growth, vision, and behavior during domestication. The construction of the genome of F. chinensis provided valuable information for the further genetic mechanism analysis of important biological processes, and will facilitate the research of genetic changes during evolution.