5种相思树和尾巨桉人工林土壤养分和酶活性特征

为揭示固氮树种土壤养分转化的酶学机制,对固氮树种[厚荚相思(Acacia crassicarpa)、黑木相思(A. melanoxylon)、卷荚相思(A.cincinnata)、大叶相思(A.auriculiformis)和马占相思(A.mangium)]及非固氮树种尾巨桉(Eucalyptusurophylla×E.grandis)人工林的土壤养分含量、酶活性及其相关性进行研究。结果表明,相思林40～60cm土层的pH均高于尾巨桉林;5种相思林土壤各土层的TP、TK含量均低于尾巨桉林,而20～40 cm土层的TC、TN含量均高于尾巨桉林,黑木相思林和马占相思林各土层的有效养分均显著高于尾巨桉林(P0.05)。0～10 cm土层中,相思林的土壤酸性磷酸酶和纤维素酶活性均高于尾巨桉林,大叶相思林的土壤脲酶、蔗糖酶、纤维素酶和芳基硫酸酯酶活性显著高于尾巨桉林(P0.05),卷荚相思林的土壤脲酶、纤维素酶、几丁质酶和淀粉酶活性显著高于尾巨桉林(P0.05)。相关分析结果表明,土壤脲酶、蔗糖酶和几丁质酶活性与AP显著负相关(P0.05),蔗糖酶和纤维素酶活性与NH4+-N显著负相关(P 0.05),脲酶、纤维素酶、芳基硫酸酯酶与土壤TK显著负相关(P0.05),几丁质酶活性与TN含量呈显著正相关(P0.05),土壤淀粉酶活性与NH4+-N呈显著正相关(P 0.05),过氧化氢酶活性与土壤TK含量呈显著正相关。可见,与尾巨桉人工林相比,在我国南方退化山地引种相思树可提高土壤关键酶的活性,对土壤有效养分具有明显改良作用,有利于退化地土壤的生态修复及人工林长期生产力的维持。     

中国古老月季‘月月粉’FT/TFL1基因的鉴定与表达分析

该研究以中国古老月季品种‘月月粉’(Rosa chinensis‘Old Blush’)为试材,根据拟南芥和草莓FT/TFL1基因家族成员的保守结构域设计引物,对‘月月粉’基因组DNA进行克隆和测序,结合数据库序列和双单倍体基因组信息进行序列比对,结果共获得了8条月季的FT/TFL1基因家族序列,且8条序列分别注释为2个FT基因(RcFT1和RcFT2)、1个BFT基因(RcBFT)、1个ATC基因(RcATC)、2个MFT基因(RcMFT1和RcMFT2)和2个PEBP基因(PEBP1和PEBP2);进化树分析结果将这8个基因分为3个亚组;结构分析显示8个基因的内含子为1～5个不等。qRT-PCR分析显示,RcFT1、RcPEBP、RcMFT1、RcMFT2和RcBFT在‘月月粉’的叶片中表达量最高,茎尖中次之;RcFT2在茎尖中的表达最高,叶片中次之;RcATC在茎尖中的表达量高于其他组织;除RcPEBP在根组织中有表达外,其他基因在根组织中几乎没有检测到。进一步表达分析显示,RcFT1和RcFT2在‘无刺光叶蔷薇’(R.wichuriana‘Basye’s Thornless')生殖生长期的叶片、茎尖中的表达量显著高于营养生长期。研究推测,具有连续开花性状的中国古老月季‘月月粉’可能具有多个开花时间(FT)基因位点,FT有可能可以作为月季生殖转换的标记基因。     

Involvement of OsPht1;4 in phosphate acquisition and mobilization facilitates embryo development in rice

Phosphate (Pi) transporters mediate acquisition and transportation of Pi within plants. Here, we investigated the functions of OsPht1;4 (OsPT4), one of the 13 members of the Pht1 family in rice. Quantitative real‐time RT‐PCR analysis revealed strong expression of OsPT4 in roots and embryos, and OsPT4 promoter analysis using reporter genes confirmed these findings. Analysis using rice protoplasts showed that OsPT4 localized to the plasma membrane. OsPT4 complemented a yeast mutant defective in Pi uptake, and also facilitated increased accumulation of Pi in Xenopus oocytes. Further, OsPT4 genetically modified (GM) rice lines were generated by knockout/knockdown or over‐expression of OsPT4. Pi concentrations in roots and shoots were significantly lower and higher in knockout/knockdown and over‐expressing plants, respectively, compared to wild‐type under various Pi regimes. ³³Pi uptake translocation assays corroborated the altered acquisition and mobilization of Pi in OsPT4 GM plants. We also observed effects of altered expression levels of OsPT4 in GM plants on the concentration of Pi, the size of the embryo, and several attributes related to seed development. Overall, our results suggest that OsPT4 encodes a plasma membrane‐localized Pi transporter that facilitates acquisition and mobilization of Pi, and also plays an important role in development of the embryo in rice.     

植物中丛枝菌根形成的信号途径研究进展

丛枝菌根(arbuscular mycorrhizal, AM)共生是丛枝菌根真菌与大多数陆地植物的根系之间形成的一种互利共生关系。植物给菌根真菌提供碳水化合物; 作为回报, 菌根真菌能够增强植物对矿质营养元素(尤其是磷)的吸收。菌根的形成过程是一系列信号交换和转导的结果, 具有严格并且一致的顺序。本文以植物中菌根形成的信号途径为主线, 对菌根真菌的形成过程和信号转导途径及其方式进行了分析和讨论。高等植物中菌根形成的信号途径与豆科植物的结瘤信号途径部分共享, 并且与钙离子信号途径相关, 但前者更为广泛。尽管该途径中很多过程目前还不十分清楚, 但是相信在不久的将来就可以揭开菌根形成过程中的众多谜团。     

The effect of the frequency of periodic irradiation on the rate of inactivation of E. coli cells

It was shown that the periodic radiation source frequency influences the rate of E. coli cell inactivation. The impulse duration from 2 microseconds to 40 ns does not influence the survival of E. coli. The analysis of the survival curves obtained permitted to assess the contribution of the direct and indirect effects of radiation to microorganism inactivation.     

Desiccation provides photosynthetic protection for crust cyanobacteria Microcoleus vaginatus from high temperature

As the dominant cyanobacterial species in biological soil crusts (BSCs), Microcoleus vaginatus often suffer from many stress conditions, such as desiccation and high temperature. In this study, the activities of light‐harvesting complexes (LHCs) and reaction centers of photosystem II (PS II) in crust cyanobacteria M. vaginatus were monitored under high temperature and desiccation conditions using chlorophyll fluorescence technology. The results showed that all the fluorescence signals were significantly inhibited by high temperature or desiccation treatments. Under high temperature conditions, it was further demonstrated that PS II reaction centers were first destructed within the first hour, then the LHCs gradually dissociated and free phycocyanin formed within 1–5 h, and the activities of all the light harvesting and reaction center pigment proteins were fully suppressed after 24 h of high temperature treatment. Furthermore, the high temperature treated M. vaginatus lost its ability to recover photosynthetic activity. On the contrary, although desiccation also led to the loss of photosynthetic activity in M. vaginatus, after rehydration in the light the fluorescence parameters including Fo, Fv and Fv/Fm could be well recovered within 12 h. It was concluded that desiccation could provide crust cyanobacteria M. vaginatus some protection from other stresses, such as high temperature demonstrated in this experiment. The combine of temperature change and precipitation pattern in the field provide a guarantee for the alternate metabolism and inactivity in crust cyanobacteria. That may be a very important strategy for the survival of crust cyanobacteria in high temperature regions.     

Heterogeneity in Colorectal Primary Tumor and Synchronous Liver Metastases

The expression profile of the ZEB1, ZEB2, VIM, CDH1, SFRP2, FOXQ1, TNC, MACC1, PLS3, CFTR, FLNA, MUC2, TFF3, and RARRES3 genes, as well as the mutational status of the KRAS, NRAS, BRAF, and PIK3CA genes, were investigated in 40 patients with colorectal cancer and liver metastases. A comparative analysis of changes in gene expression in primary tumor cells and liver metastases was performed. Statistically significant differences were found between the expression levels of the ZEB2 (p = 0.004), VIM (p < 0.001), FLNA (p = 0.04), and MUC2 (p < 0.001) genes. It was demonstrated that the overall frequency of mutations of the KRAS gene was 18/40 (45%) and the PIK3CA gene was 9/40 (23%). Mutations in the NRAS and BRAF genes were not found. The concordance between the primary tumor and metastases in the liver by mutation status was 100%.     

3D Printing Sulfur Copolymer‐Graphene Architectures for Li‐S Batteries

3D printing is becoming an efficient approach to facilely and accurately fabricate diverse complex architectures with broad applications. However, suitable inks and 3D print favorable architectures with high electrochemical performances for energy storage are still being explored. Here, sulfur copolymer‐graphene architectures with well‐designed periodic microlattices are 3D printed as a cathode for Li‐S batteries using a suitable ink composed of sulfur particles, 1,3‐diisopropenylbenzene (DIB), and condensed graphene oxide dispersion. Using thermal treatment, elemental sulfur can be reacted with DIB to produce sulfur copolymer, which can partially suppress the dissolution of polysulfides. Moreover, graphene in the architecture can provide high electrical conductivity for whole electrode. Hence, 3D printed sulfur copolymer‐graphene architecture exhibits a high reversible capacity of 812.8 mA h g^?1 and good cycle performance. Such a simple 3D printing approach can be further extended to construct many complex architectures for various energy storage devices.     

Mesoporous Hybrid Electrolyte for Simultaneously Inhibiting Lithium Dendrites and Polysulfide Shuttle in Li–S Batteries

A bifunctional hybrid electrolyte composed of mesoporous silica nanosheets and liquid electrolyte is achieved for lithium–sulfur (Li–S) batteries. This hybrid electrolyte possesses abundant mesopores (2.8 nm), thin feature (20 µm), and high ionic conductivity (1.17 × 10^?1 mS cm^?1) as well as a low interfacial resistance with electrodes. Such unique features not only enable the efficient inhibition of the growth of lithium dendrites, but also significantly prevents polysulfide shuttling. Consequently, a Li–S battery with this hybrid electrolyte exhibits a relatively high reversible capacity and good capacity retention.     

Sex-related differences in the associations between plasma free fatty acid levels and clinical features in patients with hypertrophic cardiomyopathy

Background

Previous studies have indicated that inefficient energy utilization may play a pivotal role in hypertrophic cardiomyopathy (HCM). However, whether plasma free fatty acid (FFA), a main energy substrate of heart, has an effect on HCM remains unclear. Besides, several studies have suggested sex-related differences in HCM features and FFA metabolism. Here, we aimed to explore the association between plasma FFA levels and HCM and potential effects of sex on this relation.

Methods

A total of 412 patients (age 47.8?±?12.7 years, 243 males (59.0%)) with HCM were recruited. Complete medical history was collected. Echocardiography and cardiovascular magnetic resonance imaging (CMRI) were performed. Fasting plasma FFA was determined by clinical laboratory. Left ventricular mass (LVM), maximum wall thickness (MWT), and left atrium diameter (LAD) were assessed with CMRI.

Results

The median FFA levels were 0.38 (interquartile range (IQR) 0.27–0.52) mmol/L in men and 0.40 (IQR 0.30–0.59) mmol/L in women. The FFA levels were significantly lower in men compared with those in women (p?=?0.005). Compared with women, men had greater LVM index (LVMI) (96.8?±?37.6 vs. 78.6?±?31.5 g/m², p?<?0.001). FFA levels in male patients correlated positively with LVM, LVMI, LAD, cholesterol levels, high-density lipoprotein-cholesterol (HDL-C) levels, heart rate, and systolic blood pressure (SBP). However, none of these variables were significantly associated with sqrt (FFA) in female patients except a borderline correlation of LAD (p?=?0.050). Multiple linear regression analysis was performed in male patients and revealed that HDL-C (β?=?0.191, p?=?0.002), heart rate (β?=?0.182, p?=?0.004), SBP (β?=?0.167, p?=?0.007), LVMI (β?=?0.132, p?=?0.032), and LAD (β?=?0.165, p?=?0.009) were independently associated with increasing FFA levels.

Conclusions

In patients with HCM, LVMI, LAD, HDL-C, SBP, and heart rate were independently associated with increasing plasma FFA levels in males, whereas not in females. These results suggest that sex may affect the pathogenesis of HCM through influencing FFA metabolism. And these sex-related differences should be taken into account in therapeutic approaches to influence myocardial FFA metabolism in HCM.