Environmental constraints on the inter-genus variation in the scaling relationship between leaf nitrogen and phosphorus concentrations

环境因子对叶氮、磷含量异速生长关系的属水平差异的影响植物叶片中氮(N)、磷(P)含量的异速生长关系表明了植物对这两种元素的相对投入。而,现有的研究很少关注这一关系在分类单元之间的差异及其成因。本研究基于来自全国1733个样地,属于46个木本被子植物属的2483个叶片样品,利用异速生长方程([N] = α[P]^β)分别计算了各属的叶氮、磷含量异速生长指数(β_L)。然后利用谱系路径分析检验了这些属的气候和土壤生态位条件如何影响属间的β_L的差异。生活在贫磷土壤中的属更可能表现出更高的β_L,即相对于氮而言更强的磷积累,这可能表明了植物对磷限制的抵抗倾向。此外,各属的β_L与相对应的土壤氮、磷含量异速生长指数(β_S)正相关,这可能表明了叶养分的变化受制于作为来源的土壤养分的变化。最后,包括温度和湿度在内的气候因子不会直接影响β_L的属间变化,但可能通过调节土壤养分水平发挥间接的作用。谱系关系不会影响各属β_L随环境梯度的变化。这些结果揭示了植物对氮、磷摄取的权衡关系可能受属生态位,特别是土壤生态位的影响,表明了β_L可以作为一项反映植物养分利用特征如何响应生态位差异的功能属性。     

Genetic innovations: Transposable element recruitment and de novo formation lead to the birth of orphan genes in the rice genome

Orphan genes are genetic innovations that lack homologs in other lineages. Orphan genes can rapidly originate and become substantially functional, yet the mechanisms underlying their origins are still largely unknown in plants. Here, we investigated the origin of orphan genes in the Oryza sativa ssp. japonica “Nipponbare” genome using genome‐wide comparisons with 10 closely related Oryza species. We identified a total of 37 orphan genes in the Nipponbare genome that show short sequence lengths, elevated GC content, and absence of introns. Interestingly, half of the identified orphan genes originated by way of a distinctive mechanism that involved the generation of new coding sequences through independent and rapid divergence within the inserted transposable element. Our results provide valuable insight into genetic innovations in the model rice genome that formed on a very short timescale.     

Optimization and characterization of rhamnolipid production by Pseudomonas aeruginosa NY3 using waste frying oil as the sole carbon

Yield and cost are two major factors limiting the widespread use of rhamnolipids (RLs). In the present study, waste frying oil (WFO) was used as the sole carbon source to produce environmentally friendly RLs by Pseudomonas aeruginosa NY3. The Plackett–Burman design (PBD) and Box–Behnken design (BBD) methods were used to maximize the production yield of RL. The PBD results showed that the concentrations of NaNO₃, Na₂HPO₄, and trace elements were the key factors affecting the yield of RL. Furthermore, the BBD results showed that at NaNO₃, Na₂HPO₄, and trace elements concentrations were 4.95, 0.66, and 0.64 mL/L, respectively, the average RL yield reached 9.15 ± 0.52 g/L, 1.58-fold higher than that observed before optimization. Fourier transform infrared spectroscopy (FTIR) and liquid chromatography-ion trap-time of flight mass spectrometry (LCMS-IT-TOF) were used to elucidate the diversity of RL congeners. The results showed that, after optimization, the RL congener diversity increased, and the major RL constituent was converted from di-RLs (64.04%) to mono-RLs (60.44%). These results suggested that the concentrations of the components contained in the culture medium of P. aeruginosa NY3 influenced not only the yield of RL, but also its congener distribution.     

Human bone marrow mesenchymal stem cell-derived extracellular vesicles impede the progression of cervical cancer via the miR-144-3p/CEP55 pathway

Cervical cancer is the most common gynaecological malignancy, with a high incidence rate and mortality rate in middle-aged women. Human bone marrow mesenchymal stem cells (hBMSCs) have been implicated in the initiation and subsequent development of cancer, along with the involvement of extracellular vesicles (EVs) mediating intracellular communication by delivering microRNAs (miRNAs or miRs). This study is aimed at investigating the physiological mechanisms by which EVs-encapsulated miR-144-3p derived from hBMSCs might mediate the progression of cervical cancer. The expression profiles of centrosomal protein, 55 Kd (CEP55) and miR-144-3p in cervical cancer cell lines and tissues, were quantified by RT-qPCR and Western blot analysis. The binding affinity between miR-144-3p and CEP55 was identified using in silico analysis and luciferase activity determination. Cervical cancer cells were co-cultured with EVs derived from hBMSCs that were treated with either miR-144-3p mimic or miR-144-3p inhibitor. Cervical cancer cell proliferation, invasion, migration and apoptosis were detected in vitro. The effects of hBMSCs-miR-144-3p on tumour growth were also investigated in vivo. miR-144-3p was down-regulated, whereas CEP55 was up-regulated in cervical cancer cell lines and tissues. CEP55 was targeted by miR-144-3p, which suppressed cervical cancer cell proliferation, invasion and migration and promoted apoptosis via CEP55. Furthermore, similar results were obtained by hBMSCs-derived EVs carrying miR-144-3p. In vivo assays confirmed the tumour-suppressive effects of miR-144-3p in hBMSCs-derived EVs on cervical cancer. Collectively, hBMSCs-derived EVs-loaded miR-144-3p impedes the development and progression of cervical cancer through target inhibition of CEP55, therefore providing us with a potential therapeutic target for treating cervical cancer.     

CCL7 contributes to angiotensin II-induced abdominal aortic aneurysm by promoting macrophage infiltration and pro-inflammatory phenotype

Chemokine C-C motif ligand 7 (CCL7), a member of CC chemokine subfamily, plays pivotal roles in numerous inflammatory diseases. Hyper-activation of inflammation is an important characteristic of abdominal aortic aneurysm (AAA). Therefore, in the present study, we aimed to determine the effect of CCL7 on AAA formation. CCL7 abundance in aortic tissue and macrophage infiltration were both increased in angiotensin II (Ang II)-induced AAA mice. Ex vivo, CCL7 promoted macrophage polarization towards M1 phenotype. This effect was reversed by the blockage of CCR1, a receptor of CCL7. CCL7 up-regulated JAK2/STAT1 protein level in macrophage, and CCL7-induced M1 activation was suppressed by JAK2/STAT1 pathway inhibition. To verify the effect of CCL7 on AAA in vivo, either CCL7-neutralizing antibody (CCL7-nAb) or vehicles were intraperitoneally injected 24 hours prior to Ang II infusion and subsequently every three days for 4 weeks. CCL7-nAb administration significantly attenuated Ang II-induced luminal and external dilation as well as pathological remodelling. Immunostaining showed that CCL7-nAb administration significantly decreased aneurysmal macrophage infiltration. In conclusion, CCL7 contributed to Ang II-induced AAA by promoting M1 phenotype of macrophage through CCR1/JAK2/STAT1 signalling pathway.     

A DNA-based Analysis of a Microbial Technique for the Prospecting of Oil and Gas Applied to a Known Oil Field,China

To evaluate the application of a DNA-based analysis of a microbial technique for oil and gas prospecting, the hydrocarbon potential predicted using the methanotrophic pmoA and propanotrophic prmA genes as targets was investigated in soil above a known oil reservoir. In total, 82 soil samples were collected at 50-cm depths above the Xiliu oil reservoir for quantitative real-time polymerase chain reaction (RT-PCR) analysis. The pmoA gene content ranged from 0 to 2.7 × 10⁶ copies/g dw, whereas that of prmA varied from 0 to 1.6 × 10⁶ copies/g dw. Microbial anomaly distribution maps of normalized values for the prmA gene as a main indicator suggested that the area with the highest potential of prospecting was an undeveloped location, and an area with a relatively large prmA background was identified at this oil-producing site. The areas of microbial anomaly exhibited different prmA/pmoA ratios (20, 1–5, 0.0n–0.25 and 0), and this ratio may be used as an indicator for predicting the properties of oil and gas reservoirs and biogenic methane or the influence of oil-producing activities. Our results suggest that a DNA-based analysis of a microbial technique is a powerful tool for oil and gas prospecting. This study provides a new microbial technique for the prospecting of oil and gas.