内生黑曲霉JS-1对稻瘟病的拮抗作用研究

利用平板对峙法和牛津杯法,从疏花水柏枝、金银花、秋华柳的内生菌中,筛选出1株对稻瘟病菌具有很强抑制作用的菌株JS-1。经生理生化实验和18S rDNAITS序列分析,确定该菌株为黑曲霉(Aspergillus niger)。实验结果表明,JS-1发酵液作用稻瘟病菌后,稻瘟病菌的菌丝变细,分支减少,菌丝基质颜色变浅,作用72 h后干重显著降低。进一步实验表明,该菌产生的活性物质位于其发酵液的乙酸乙酯酯相部位,对稻瘟病病菌抑制率高达96.1%。大田实验数据（天然接种圃）显示,添加该物质后,丰两优4号（中感）和广陆矮4号（易感）叶瘟病情指数分别只有16.25%和32.48%,对稻瘟病的防治取得了很好的效果,说明该菌株具有开发成高效生物农药的巨大潜能。     

Seasonal and interannual variations of ecosystem photosynthetic characteristics in a semi-arid grassland of Northern China

北方半干旱草原生态系统光合参数的季节和年际变异 生态系统表观量子效率(α)、最大光合速率(P_max)和暗呼吸速率(R_d)不仅反映了生态系统水平 光合生理特征,同时也是碳循环模型中光合过程模拟的关键参数。气候和植被因子都会影 响光合参数的季节和年际变异,但二者在光合参数调控过程中的相对贡献和作用途径尚不清晰。本研究基于连续12年(2006–2017)的涡度相关观测数据,分析了内蒙古半干旱典型草原光合参数的季节和年际变化规律;利用回归分析和结构方程模型(SEM)方法明晰了环境和生理调控的作用途径及相对贡献。结果发现,光合参数(α、P_max和R_d)均表现出单峰的季节变化趋势,并呈现明显的年际波动。温度(T_a)和土壤含水量(SWC)的变化共同影响光合参数的季节变化,而SWC主导了其年际变异。α和R_d的变化主要由T_a决定,而Pmax的变化主要受SWC的影响。SEM模型分析表明,除了直接作用外,环境因子主要通过影响冠层水平气孔导度(gc)对光合参数和碳同化生理过程进行调控。此外,叶面积指数对光合参数特别是Pmax的季节和年际变异起主要调控作用。以上结果明确了环境和植被共同决定了生态系统水平光合参数的季节和年际变异,并强调了在水分受限的草原生态系统中,植被生理调控在光合碳同化能力和碳汇功能评估中的重要作用。     

Carbon and water fluxes in ecologically vulnerable areas in China

Ecologic vulnerable areas (EVAs) are the regions where ecosystems are fragile and vulnerable to suffer from degradation with external disturbances, e.g. environmental changes and human activities (Feng et al. 2022; Wang et al. 2019). EVAs in China are widely distributed and account for more than 55% China’s land area (Ministry of Ecology and Environment of the People’s Republic of China 2008). The ecosystem in EVAs, chartered with low stability, weak resistance and high vulnerability, has been experiencing significant degradation owing to the impacts of global climate change and human activities (Bai et al. 2018; Chen et al. 2021; Yu et al. 2022). The EVAs in China are not only the most serious areas of environmental degradation, but also the most poverty-stricken regions (Wang et al. 2019). Harsh environmental condition (drought, low temperature and strong radiation) and limited resource supply (water, soil nutrients, etc.) constrain the vegetation productivity and ecosystem services of EVAs (Li et al. 2021). Climate change adds new challenges with warmer temperatures, changing rainfall regime and increasing frequency of extreme events (drought, heat wave, storms, etc.), which make it is more difficult to predict the changes of ecosystem processes and functions in future scenarios (Piao et al. 2020; Reid et al. 2014). Carbon and water fluxes are the core ecosystem processes, which is linked to diverse ecosystem services (Lian et al. 2021). Therefore, clarifying the variations and controls of ecosystem carbon and water fluxes is an effective approach to clarifying how ecosystem respond to global change in EVAs (Baldocchi 2020). As the only technique can directly measure the carbon, water and energy fluxes between vegetation and atmosphere, eddy covariance technique has been considered as a standard method for flux observations (Chen et al. 2020). By integrating long-term, eddy covariance measurements over time and space, researches are able to assess ecosystem metabolism at different time scales (hours to decades) (Forzieri et al. 2020; Han et al. 2020; Jung et al. 2017). Eddy covariance measurements also produce information on how ecosystem respond to the changes in climate, which is useful for assessing ecosystem carbon sequestration (Hu et al. 2018), water and energy balance (Forzieri et al. 2020), resource use efficiency (Liu et al. 2019) and ecosystem feedback to climate change (Huang et al. 2019; Piao et al. 2020; Yue et al. 2020). Long-term flux measurements are also vital for detecting the responses of ecosystem functions to extreme events, optimizing and validating models on regional and global scales (Baldocchi 2020). Combining with remote sensing and ecosystem modeling techniques, scientists can upscale and evaluate the functional relations between carbon and water fluxes with environmental variables at high resolution and across diverse spatial/temporal scales (Niu et al. 2017; Xia et al. 2020).     

A cancer protein microarray platform using antibody fragments and its clinical applications

Antibody microarrays have shown great potential for measurement of either a spectrum of target proteins in proteomics or disease-associated antigens in molecular diagnostics. Despite its importance, the applications of antibody microarrays are still limited by a variety of fundamental problems. Among them, cross-reactivity significantly limits the multiplexing ability in parallel sandwich immunoassays. As a result, it is very important to design new capture probes in order to incorporate a universal label into the assay configuration. In this report, an antibody fragments (F(ab')2) microarray platform for serum tumor markers was developed. Each antigen was detected at different concentrations to assemble its calibration curve, and combinations of different markers were tested to examine the specificity of simultaneous detection based on the F(ab')2 microarrays. Diagnostics of serum samples with this cancer antibody microarray platform and immunoradiometric assays (IRMA) were also performed. Wide range calibration curves (0-1280 U mL(-1)) were obtained for each tumor marker. Comparative studies demonstrated that such F(ab')2 microarrays exhibited both moderately improved sensitivity and better specificity than full-sized monoclonal antibody microarrays. It is also demonstrated that this microarray platform is quantitative, highly specific and reasonably sensitive. More importantly, clinical applications of our F(ab')2 microarray platform for upwards of 100 patient serum samples clearly show its potential in cancer diagnostics.     

内蒙古温带典型草原羊尿斑块土壤化学特性变化

在内蒙古冷蒿小禾草草原1989年围封禁牧地,研究了天然羊尿尿斑土壤化学特性的变化规律,结果表明,土壤pH值于施尿后第2天达到最大值,以后呈下降趋势,58天后pH值基本稳定在6．5左右且低于对照区水平,施尿区土壤可溶性有机碳含量的变化趋势与pH值的变化基本一致,两者存在显著的正相关关系(P<0．01)．施尿后土壤总可溶性磷含量显著提高(P<0．05),第2天达到最大值(35．1mg·L^-1)。总可溶性磷各组分钼酸反应磷、可溶性有机磷和可溶性缩合磷百分比均存在两个明显的变化阶段,钼酸反应磷和可溶性有机磷与可溶性缩合磷存在显著的负相关关系(P<0．05)．施尿区土壤NH4^+-N在第2天达到最大值。以后呈下降趋势;NO3-N含量14天后开始显著增加,并于第21天达到最大值,其变化呈现明显的“双峰型”特征,并较NH4^+-N存在显著的时滞现象;施尿后土壤可溶性有机氮含量显著增加,并表现为“双峰型”变化特征。     

Development of enhancer trap lines for functional analysis of the rice genome

Enhancer trapping has provided a powerful strategy for identifying novel genes and regulatory elements. In this study, we adopted an enhancer trap system, consisting of the GAL4/VP16-UAS elements with GUS as the reporter, to generate a trapping population of rice. Currently, 31 443 independent transformants were obtained from two cultivars using Agrobacterium-mediated T-DNA insertion. PCR tests and DNA blot hybridization showed that about 94% of the transformants contained T-DNA insertions. The transformants carried, on average, two copies of the T-DNA, and 42% of the transformants had single-copy insertions. Histochemical assays of approximately 1000 T0 plants revealed various patterns of the reporter gene expression, including expression in only one tissue, and simultaneously in two or more tissues. The expression pattern of the reporter gene in T1 families corresponded well with the T0 plants and segregated in a 3 : 1 Mendelian ratio in majority of the T1 families tested. The frequency of reporter gene expression in the enhancer trap lines was much higher than that in gene trap lines reported previously. Analysis of flanking sequences of T-DNA insertion sites from about 200 transformants showed that almost all the sequences had homology with the sequences in the rice genome databases. Morphologically conspicuous mutations were observed in about 7.5% of the 2679 T1 families that were field-tested, and segregation in more than one-third of the families fit the 3 : 1 ratio. It was concluded that GAL4/VP16-UAS elements provided a useful system for enhancer trap in rice.     

微小根毛霉致病株的原生质体形成条件

建立了重要医学真菌──肺微小根毛霉的原生质体生成系统。采用溶细胞酶以及蜗牛酶与纤维素酶联合作用的方式获得了大量原生质体,处于指数生长期、生长旺盛的幼龄菌丝对破壁酶比生长缓慢或老龄菌丝更敏感;作为渗透压稳定剂,无机盐类要好于有机物;原生质体的较适生成温度为31℃。     

The Effect of Adjuvant Chemotherapy on Survival in Patients with Residual Nasopharyngeal Carcinoma after Undergoing Concurrent Chemoradiotherapy

Background

Guidelines from the U.S. National Comprehensive Cancer Network have recommended use of concurrent chemoradiotherapy (CCRT), followed by a 3-cycles combination of platinum and 5-fluorouracil chemotherapy as standard treatment for nasopharyngeal carcinoma (NPC). The benefits of CCRT for treatment of locally advanced NPC have been established. Whether platinum and 5-fluorouracil chemotherapy should be routinely added to locally advanced NPC after CCRT is still open to debate. Whether adjuvant chemotherapy provides an additional survival benefit for the subgroup of patients with residual nasopharyngeal carcinoma who have undergone CCRT is also unclear. This retrospective study was initiated to determine the survival benefit of adjuvant chemotherapy (AC) in residual NPC patients who have undergone concurrent chemoradiotherapy.

Methods

The retrospective study included 155 nasopharyngeal carcinoma patients who had local residual lesions after the platinum-based CCRT without or with AC. Kaplan-Meier analysis and the log-rank test were used to estimate overall survival (OS), failure-free survival (FFS), local relapse-free survival (LRFS) and distant metastasis-free survival (DMFS).

Results

Median follow-up was 47 months. Adjuvant cisplatin or nedaplatin plus 5-fluorouracil chemotherapy did not significantly improve 3-year OS, LRFS, FFS, and DMFS for patients with residual nasopharyngeal carcinoma after undergoing CCRT. The 3-year OS rates for the no-AC group and AC group were 71.6% and 73.7%, respectively (P= 0.44). The 3-year FFS rates for no-AC group and AC group were 57.5% and 66.9%, respectively ((P= 0.19). The 3-year LRFS rates for no-AC group and AC group were 84.7% and 87.9%, respectively ((P= 0.51). The 3-year DMFS rates for no-AC group and AC group were 71.4% and 77.4%, respectively ((P= 0.23).

Conclusions

Since we did not find sufficient data to support significant survival in 3-year OS, LRFS, FFS, and DMFS, whether Adjuvant cisplatin or nedaplatin and 5-fluorouracil chemotherapy should be routinely added to residual nasopharyngeal carcinoma patients after undergoing CCRT remain uncertain.     

Small RNAs and Gene Network in a Durable Disease Resistance Gene—Mediated Defense Responses in Rice

Accumulating data have suggested that small RNAs (sRNAs) have important functions in plant responses to pathogen invasion. However, it is largely unknown whether and how sRNAs are involved in the regulation of rice responses to the invasion of Xanthomonas oryzae pv. oryzae (Xoo), which causes bacterial blight, the most devastating bacterial disease of rice worldwide. We performed simultaneous genome-wide analyses of the expression of sRNAs and genes during early defense responses of rice to Xoo mediated by a major disease resistance gene, Xa3/Xa26, which confers durable and race-specific qualitative resistance. A large number of sRNAs and genes showed differential expression in Xa3/Xa26-mediated resistance. These differentially expressed sRNAs include known microRNAs (miRNAs), unreported miRNAs, and small interfering RNAs. The candidate genes, with expression that was negatively correlated with the expression of sRNAs, were identified, indicating that these genes may be regulated by sRNAs in disease resistance in rice. These results provide a new perspective regarding the putative roles of sRNA candidates and their putative target genes in durable disease resistance in rice.