Tectonic and orbital forcing of the South Asian monsoon in central Tibet during the late Oligocene.

The modern pattern of the Asian monsoon is thought to have formed around the Oligocene/Miocene transition and is generally attributed to Himalaya-Tibetan Plateau (H-TP) uplift. However, the timing of the ancient Asian monsoon over the TP and its response to astronomical forcing and TP uplift remains poorly known because of the paucity of well-dated high-resolution geological records from the TP interior. Here, we present a precession-scale cyclostratigraphic sedimentary section of 27.32 to 23.24 million years ago (Ma) during the late Oligocene epoch from the Nima Basin to show that the South Asian monsoon (SAM) had already advanced to the central TP (32°N) at least by 27.3 Ma, which is indicated by cyclic arid-humid fluctuations based on environmental magnetism proxies. A shift of lithology and astronomically orbital periods and amplified amplitude of proxy measurements as well as a hydroclimate transition around 25.8 Ma suggest that the SAM intensified at ~25.8 Ma and that the TP reached a paleoelevation threshold for enhancing the coupling between the uplifted plateau and the SAM. Orbital short eccentricity-paced precipitation variability is argued to be mainly driven by orbital eccentricity-modulated low-latitude summer insolation rather than glacial-interglacial Antarctic ice sheet fluctuations. The monsoon data from the TP interior provide key evidence to link the greatly enhanced tropical SAM at 25.8 Ma with TP uplift rather than global climate change and suggest that SAM's northward expansion to the boreal subtropics was dominated by a combination of tectonic and astronomical forcing at multiple timescales in the late Oligocene epoch.

Artesunate-induced ATG5-related autophagy enhances the cytotoxicity of NK92 cells on endometrial cancer cells via interactions between CD155 and CD226/TIGIT.

Uterine corpus endometrial carcinoma (UCEC) is the most prevalent gynecologic cancer in developed countries and lacks efficient therapeutic strategies. Artesunate (ART), a well-modified derivate of artemisinin, exerts potent anti-cancer effects apart from its classical anti-malaria feature. Autophagy is a universal double-edged process in cell survival, and CD155 is a novel immune checkpoint highly expressed in numerous cancers. However, the relationships among ART, autophagy, and CD155 remain unclear in UCEC. In this study, we discovered that ART not only inhibited proliferation and migration, promoted apoptosis, but also induced autophagy in UCEC cells. Meanwhile, ART-induced autophagy elevated the level of CD155 in UCEC cells, thereby enhancing the cytotoxicity of natural killer cell line (NK92) by modulating the interactions between CD155 and its receptors in NK92 cells via upregulation of co-stimulator CD226 and downregulation of co-inhibitor TIGIT. Additionally, ART regulated CD155 partially via ATG5, and knockdown of ATG5 dampened the expression of CD155 in UCEC cells, thus decreasing the cytotoxicity of NK92 cells. Therefore, this study demonstrated the dual anti-cancer effects of ART as it could induce cell-killing directly and indirectly, which provides novel insights into the anti-cancer mechanisms of ART on UCEC.

[Impacts of thinning on canopy structure and understory light in secondary poplar-birch forests.] / é—´ä¼å¯¹æ¨æ¡¦æ¬¡ç”Ÿæž—å† å±‚ç»“æž„åŠæž—ä¸‹å ‰ç §çš„å½±å“.

The variation of forest canopy structure and understory light caused by natural or human disturbances might account for environmental heterogeneity and species diversity in the understory. These factors play an important role in driving the structure, process and pattern in forest ecosystem. We set up two 0.25 hm2 permanent plots in secondary Betula platyphylla-Populus davidiana forests on the Taoshan Forest Farm, one of which was thinned in 2012 and the other one remained natural. The canopy images of two plots were collected by hemispherical photography technology from 2012 to 2016 and 2018. Analysis of variance and Markov matrix were applied to examine the dynamics of canopy structure, understory light, and canopy closing process after thinning. The results showed that thinning was effective in adjusting canopy structure and understory light availability. Such process lasted for a long time and the adjusting effect decreased over time. After thinning, the change rate of canopy structure and understory light decreased over time. The tree canopy quickly closed during the first three years and then reached a stable state. Understory light availability was positively correlated with canopy openness and negatively correlated with leaf area index. The correlation between understory scattered radiation and canopy structural parameters was the strongest. The correlation between canopy structure and understory light in the thinning plot was stronger than that of the control plot. After thinning, the recovery rate of canopy structure was related to the canopy openness, with larger canopy openness being accompanied with higher recovery rate. Thus, less time was required for the transfer to smaller canopy openness. The Markov matrix model could simulate changes in distributions of canopy structure and could be used to predict the dynamics of the canopy structure.

[Minimal functional domain of cytidine 5'-monophosphate N-acetylneuraminic acid (CMP-NeuAc) synthetase from Escherichia coli].

In comparison with its counterpart from N. meningitides, all conserved motifs were found in the N-termini of E. coli CMP-NeuAc synthetase. E. coli CMP-NeuAc synthetase seems to have redundant C-termini with a less effect on its activity. To explain this speculation, a series of recombinant DNAs with deletion from 3'-end of CMP-NeuAc synthetase were produced by PCR, ligated into expression vector pET-15b and expressed in BL21(DE3)pLysS. After induction with IPTG, we found that the recombinant enzyme with deletion of 189 amino acids from C0termini retained its activity. This result demonstrates that the 229 amino acids of N-termini was the minimal functional domain of E. coli CMP-NeuAc synthetase. The deletions altered the optimum pH and thermostability of active truncated enzymes, indicating that the truncated C-terminal amino acids of E. coli CMP-NeuAc synthetase could affect the conformation of the enzymatic catalytic domain and therefore affect its catalytic activity and thermostability, although it is not involved in enzymatic activity directly.