High efficient broad-spectrum Bradyrhizobium elkanii Y63-1

Soybean(Glycine max),the primary source of high-quality plant protein,plays a crucial role as a grain and oil crop in China.Harnessing the full potential of symbiotic nitrogen fixation in soybean production holds immense significance for agriculture and ecology alike.Zhongdou 63,a newly developed early-maturing summer soybean cultivar in 2021,exhibits remarkable traits such as high yield,superior quality,multi-resistance,and wide adaptability.In this study,eight distinct rhizobia strains from diverse regions were meticulously screened to identify highly effective strains specifically suited for Zhongdou 63.The aboveground biomass,plant height,chlorophyll content,root length,nodule number,and nodule dry weight of Zhongdou 63 were measured and the data were subjected to statistical analysis.The results demonstrated that Y63-1 is a predominant strain of Zhongdou 63.Subsequently,we conducted further investigations on the broad-spectrum nodulation characteristics of Y63-1.Ten representative soybean cultivars were individually inoculated with Y63-1 and subsequently analyzed for nodule numbers and nodule dry weight in their symbiotic systems with rhizobia.The findings revealed that Y63-1 effectively formed nodules with all ten soybean varieties tested.In summary,our current study identified highly efficient broad-spectrum Bradyrhizobium elkanii strain Y63-1 as the predominant strain in Zhongdou 63 and provided a theoretical foundation for enhancing yield potential not only in Zhongdou 63 but also in other varieties through inoculation with highly efficient rhizobia in production.

Photoluminescence and Ce^(3+)→Tb^(3+)→Eu^(3+) Energy Transfer Processes of the Ce^(3+)/Tb^(3+)/Eu^(3+)-doped β-NaYF_(4) Phosphors with Broadened Excitation Spectrum

Ce^(3+)/Tb^(3+) co-doped and Ce^(3+)/Tb^(3+)/Eu^(3+) tri-doped β-NaYF_(4) photoluminescent microcrystals using oleic acid as surfactant were synthesized using the solvothermal method.Their microstructural characteristics and photoluminescence properties were investigated in detail.They have the shape of hexagonal prism bipyramids with uniform particle size,which decreases with the concentrations of Tb^(3+) and Eu^(3+).The energy transfer processes of both the Ce^(3+)→Tb^(3+) and the Ce^(3+)→Tb^(3+)→Eu^(3+) were systematically studied.Compared with Eu^(3+) or Tb^(3+) single-doped β-NaYF_(4) microcrystals,the sensitization by Ce^(3+) for the photoluminescence of Tb^(3+) and Eu^(3+) leads to a broad excitation spectral bandwidth in the ultraviolet (UV) range.Meanwhile,the corresponding optical absorption efficiency is greatly enhanced.High energy transfer efficiencies have been observed from Ce^(3+) to Tb^(3+) and from Tb^(3+) to Eu^(3+).

Screening of Broad-spectrum Resistance Resources against Rice Bacterial Leaf Streak

[ Objectives] Rice materials with broad-spectrum resistance against several pathogenic strains of Xanthomans oryzae pv. Oryzicola （Xooc） at multiple growth stages were screened, in order to provide reliable resistance sources for variety breeding against rice bacterial leaf streak. [ Methods] A total of 1 100 rice lines with rich genetic background were offered as selective objects, and highly susceptible cultivar Jingang 30 was used as the control. Inoculation was carried out with five strong pathogenic strains of Xooc through acupuncture method at various growth stages for resistance identification. [ Results] Fourteen disease-resistant materials were obtained through preliminary screening, accounting for 1.27% of the total materials. Nine materials moderately resistant to bacterial leaf streak were obtained via secondary screening, accounting for 0.82% of the total materials. Besides, three of them （ RL6, RL9 and RLL4） were resistant to a number of pathogenic strains of Xooc at three growth stages. In particular, RL16 presented broad-spectrum resistance to multi-strains with high resistance levels. Six of them （ RI2, RIA, RIS, RL8, RL11 and RL12） were resistant to single strain at single growth stage. [ Conclusions] The obtained three materials have broad-spectrum resistance to bacterial leaf streak at multiple growth stages, which can be served as an important source to cultivate disease-resistant rice varieties. RL6 maintains high broad-spectrum resistance at all growth stages, which can be used as a prior resistance source for rice variety breeding. Six materials obtained with resistance against bacterial leaf streak at particular growth stages can be used as candidate resistance sources.

Forming of Space Charge Wave with Broad Frequency Spectrum in Helical Relativistic Two-Stream Electron Beams

We elaborate a quadratic nonlinear theory of plural interactions of growing space charge wave （SCW） harmonics during the development of the two-stream instability in helical relativistic electron beams. It is found that in helical two-stream electron beams the growth rate of the two-stream instability increases with the beam entrance angle. An SCW with the broad frequency spectrum, in which higher harmonics have higher amplitudes, forms when the frequency of the first SCW harmonic is much less than the critical frequency of the two-stream instability. For helical electron beams the spectrum expands with the increase of the beam entrance angle. Moreover, we obtain that utilizing helical electron beams in multiharmonic two-stream superheterodyne free-electron lasers leads to the improvement of their amplification characteristics, the frequency spectrum broadening in multiharmonic signal generation mode, and the reduction of the overall system dimensions.

Co-production of Multiple Antimicrobial Compounds by Bacillus amyloliquefaciens WY047,a Strain with Broad-Spectrum Activity

A bacterial strain WY047 was isolated from fermented grains and the bacterium was identified as Bacillus amyloliquefaciens, based on morphological, biochemical, and physiological tests, and analysis of 16S rRNA and gyr A sequences. The culture supernatant of WY047 demonstrated inhibition ofa wide spectrum ofbacteria(Gram positive and Gram negative) and fungi. Nine pairs ofprimers were designed and six genes( bmyD, fenA, hag, ituA, mrsA, and tasA) ofantimicrobial substances were detected by PCR, one ofwhich was isolated by 80% ammonium sulfate precipitation, D201 resin anion-exchange chromatography, and Sephadex G-75 filtration column. The purified peptide was estimated to be 35,207 Da and identified as flagellin by MALDI-TOF mass spectrometry. Another four antimicrobial substances were extracted with methanol and identified as iturin A, fengycin, bacillomycin D, and mersacidin through the liquid chromatography–mass spectrometry(LC–MS) method. The sixth possible peptide encoded by tas A could not be isolated in this study; however, the broader spectrum suggested huge application prospects.

A Broad Spectrum Identification Approach for Two Generations of epsps GM Soybeans

In order to accurately identify the first and second generations of epsps genetically modified(GM) soybeans and related products,a broad spectrum identification approach was established using the real time Polymerase Chain Reaction(PCR) principle according to the homology of epsps genes of the first and second generations of GM soybeans.A pair of primer and probe was designed to simultaneously identify exogenous gene epsps of two generations of GM soybeans.Besides,evaluation was carried out on this approach from the accuracy,specificity,sensitivity and reproducibility.The experimental results indicated that(ⅰ) although there is certain difference in epsps gene sequence between the first and second generations of epsps genetically modified(GM) soybeans,the established approach can simultaneously detect the epsps genes of the bean curd using two generations of soybean as raw materials;(ⅱ) in the accuracy and specificity experiment,only cp4-epsps genes of two generations of GM soybeans were detected,so this approach has high specificity and accuracy;(ⅲ) in the experiment of 5 copies of epsps genes of 40 repeated identification reaction systems,5 copies of epsps genes can be detected each time,therefore at 100% confidence level,this approach can identify 5 copies of epsps genes,showing that this approach has high sensitivity and reproducibility.

Increasing Incidence of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae (ESBL) and the Relation to Consumption of Broad-Spectrum Antimicrobial Agents 2003-2011 in a Large Area of Copenhagen, Denmark

Purpose: To investigate 1) the development in the incidence of ESBL-producing bacteria in hospitals and primary health care, 2) the contribution of primary health care to the incidence of ESBL-producing bacteria, and 3) the development in resistance patterns for all Escherichia coli and Klebsiella pneumoniae isolates in relation to antimicrobial consumption in hospitals and primary health care. Methods: ESBL-data were retrospectively collected from bacterial isolates from all specimens received at the Department of Clinical Microbiology from 2003 to 2011 together with the corresponding patient data. ESBL-production was detected in isolates from 1067 of 59,373 patients (1.8%) with an E. coli infection and in 263 of 8660 patients (3.0%) with a K. pneumoniae infection. Results: From 2003 to 2009, an increase in patients with an ESBL-producing isolate occurred in both hospitals and primary health care at the same time as an increased consumption of broad-spectrum antimicrobial agents was seen. Interventions to reduce prescription of cephalosporins and ciprofloxacin at the hospitals from 2010 resulted in a remarkable decrease in patients with ESBL-producing K. pneumoniae whereas a continuing increase was seen in patients with ESBL-producing E. coli both at hospitals and in primary health care. The proportion of patients with community-acquired ESBL-producing E. coli was stable with an increase of only 1.4% from 2007 to 2011. Conclusions: Reduction in prescription of broad-spectrum antimicrobial agents at the hospital level had an important impact on the incidence of ESBL-producing K. pneumoniae, but not on ESBL-producing E. coli.

Effectiveness of a Broad-Spectrum Sunscreen in the Prevention of Melasma in Asian Pregnant Women

Chloasma, or melasma, is a commonly acquired pigmentary disorder among Asian women. It may be considered as a physiological change during pregnancy. The incidence in Asian women is higher than that in other ethnic groups but further epidemiologic data are needed. There are very few studies related to the benefits of sunscreens to prevent this dermatosis. The aim of this study was to assess the effectiveness of a broad-spectrum sunscreen in the prevention of melasma in Korean pregnant women. We tested the effectiveness and tolerance of a sunscreen product (SPF 50+, UVA-PF 30) during a 12-month clinical trial including 220 Korean parturients with skin type III and IV. 217 women completed the study. Only 3 (1%) of the study population developed melasma, which was mild (MASI grade between 1.2 and 2.7). In addition, the clinical effectiveness of the evaluated sunscreen was judged “good to excellent” by the majority of study participants and by the research dermatologists. The “excellent” tolerance of the sunscreen under evaluation was confirmed “good” to “excellent” in 95% and 97% of cases. This study clearly demonstrates that this broad-spectrum sunscreen is well tolerated and effective in the prevention of melasma in Korean pregnant women. Although treatment remains elusive, prevention is possible.

传统发酵乳品中产广谱细菌素乳酸菌选育

为选育产广谱细菌素乳酸菌,采用琼脂扩散法对甘肃牧区传统发酵乳品中分离纯化的96株乳酸菌进行了筛选,并确定产细菌素菌株,具有最佳抑菌效果的菌株经重离子束12C6+辐照诱变,再采用培养皿分区法进行6种指示菌广谱抑菌性能比较。结果表明,琼脂扩散法筛选出抑菌效果最佳的产细菌素菌株Lp1,经辐照诱变得到98株突变菌,选育出对大肠埃希氏菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、单核细胞增生李斯特氏菌(Listeria monocytogenes)、沙门氏菌(Salmonella)、志贺氏菌(Shigella)和克罗诺杆菌(Cronobacter)抑菌性能均明显优于出发菌株Lp1的5株突变株L088、L087、L063、L049、L010进行广谱抑菌试验,其中菌株L088和L063为广谱抑菌性能较好菌株,突变株L088对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高47.81%、33.28%、22.97%、45.25%、21.39%、40.21%,突变株L063对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高54.27%、29.18%、25.37%、58.03%、17.85%、42.13%。采用培养皿分区法可同时在1个培养皿中完成检测6种指示菌的抑菌试验,可高效筛选产广谱细菌素乳酸菌。

高性能YVO_(4)基稀土杂化发光材料的构建及其能量传递机制

采用溶剂热和离子交换两步实验法,以YVO_(4)为无机基质,2-噻吩甲酰三氟丙酮(TTA)为有机配体,构建了具有核壳结构的YVO_(4)∶Eu^(3+)@YVO_(4)∶Eu^(3+)-TTA稀土杂化发光材料,研究了其高效的发光性能和内部的能量传递机制。结果表明,在621nm的监控波长下,YVO_(4)∶Eu^(3+)@YVO_(4)∶Eu^(3+)-TTA稀土杂化发光材料在280~420nm范围内有两个很强的吸收峰(即V-O峰和TTA特征吸收峰)。YVO_(4)基质通过交换作用能量传递,而TTA有机配体通过分子内能量传递,可将吸收的紫外光能量有效地传递给Eu^(3+),从而实现了Eu^(3+)更高效的可见光(红光)发射。

合成生物学在新冠病毒广谱疫苗研发中的应用

新型冠状病毒(SARS-CoV-2)自2019年底引发疫情至今,已经变异出Alpha、Beta、Delta和Omicron等不同谱系。传统疫苗的抗原序列来源于某一自然分离株的原始序列,疫苗迭代速度跟不上病毒变异的速度,导致突破性感染的发生,研发跨谱系的广谱疫苗是预防这类高变异呼吸道病毒的迫切需求。随着合成生物技术的发展,抗原的多价偶联、核心抗原模块的提取、抗原内部保守表位的工程化设计、抗原表位展示技术、计算指导的抗原重构等抗原“再设计”方案得以实现,提高了抗原的免疫原性和广谱性。合成生物学还体现在疫苗产品的生产工艺环节,基因工程表达的疫苗抗原以纳米颗粒、病毒载体、核酸、亚单位的形式,借助细菌、酵母、植物、昆虫或哺乳动物细胞等表达平台进行规模化生产。本文综述了近年来合成生物技术在广谱疫苗(尤其是广谱新冠病毒疫苗)多种设计策略中的应用情况,总结了合成生物技术如何通过反向疫苗学的设计展示全新的共性抗原表位和交叉抗原位点,达到“以不变应万变”的广谱保护效果。本文还讨论了多种广谱疫苗设计策略的应用场景及面临的挑战。基于合成生物技术的马赛克设计策略、保守表位工程化设计策略、计算共识序列策略和新型佐剂策略,结合不同的疫苗技术路线,可提高疫苗的免疫原性、广谱保护性和安全性。这为高变异病毒的疫苗研发提供了合成生物学的新思路。

水稻乙酰乳酸合酶Ala179Val突变赋予ALS抑制剂类除草剂广谱抗性

为了鉴定新型水稻突变体ALS179对乙酰乳酸合酶(ALS,acetolactate synthase)抑制剂类除草剂的抗性,本研究以野生型水稻华航31(HH31)、耐咪唑啉酮除草剂水稻ALS627突变体和甲基磺酸乙酯(EMS,ethyl methyl sulfone)诱变的新型水稻突变体ALS179为试验材料,通过不同浓度下的4类乙酰乳酸合酶抑制剂类除草剂包衣浸种和苗期喷施处理,进一步测定表型及相关酶活性指标来探究突变体ALS179的抗性。结果表明,经过除草剂包衣浸种以及苗期喷施处理后,突变体ALS179对苯磺隆、咪唑乙烟酸、双草醚及啶磺草胺具有不同程度的抗性,且乙酰乳酸合酶、过氧化物酶、过氧化氢酶和超氧化物歧化酶的活性随除草剂浓度的升高呈下降趋势。除了20×,30×的咪唑乙烟酸处理条件下过氧化氢酶和过氧化物酶的酶活性低于野生型HH31外,其他处理条件下ALS179的乙酰乳酸合酶、超氧化物歧化酶、过氧化氢酶和过氧化物酶的酶活性均高于野生型HH31。因此,本研究发现Ala179Val突变赋予了对ALS抑制剂类除草剂的广谱抗性,为后续ALS类除草剂广谱抗性水稻品系的培育提供遗传种质资源。

小分子化学污染物广谱识别性核酸适配体的制备及其应用进展

作为新型生物识别材料,广谱识别性核酸适配体在食品和环境中小分子化学污染物及其结构类似物的同时检测中有很大的应用潜力。本文综述了有关腺苷受体拮抗剂、被非法滥用活性物质、抗炎药物、抗微生物药物、工业化学品、农药、类固醇雌激素和毒素等小分子化学污染物广谱识别性核酸适配体的筛选方法和优化策略,归纳总结了109条核酸适配体序列和平衡解离常数(或相对亲和力)及其所用的测定方法,并简要介绍了基于广谱识别性核酸适配体所开发的生物传感器,以期为食品和环境中小分子化学污染物快速检测产品的更新换代提供参考。

芬太尼类物质的荧光适配体传感器构建及应用

近年来报道,新精神活性物质伪装成零食、饮料等形式进入并潜伏在大众日常生活中。其中芬太尼类物质是典型代表,市场监管和公安侦查均迫切需要现场快速筛查技术和产品的支撑。基于适配体的快速检测技术发展迅速,然而特异性芬太尼类物质适配体研究相对缺乏。该文以芬太尼类物质的核心结构类似物的裁剪适配体为识别元件,以Fe_(3)O_(4)作为猝灭剂和磁分离剂,利用荧光猝灭技术构建适配体传感平台,对芬太尼类物质实现广谱识别。结果表明,该荧光传感器检测芬太尼类物质为100~500μg/L,R为0.9977,检测限为19.7μg/L,相对标准偏差为5.91%~7.51%,在非居民用水和居民用水中加标回收率分别为81.14%~91.54%和106.7%~117.4%,可用于水样芬太尼类物质的快速筛查,填补芬太尼总量广谱快速检测方面研究的空白。

Y波导温致半波电压特性对谐振式光纤陀螺的影响

针对基于宽谱光源的谐振式光纤陀螺(resonant fiber optic gyroscope, RFOG)中Y波导调制器半波电压的温度影响,开展了Y波导温致半波电压特性对谐振式光纤陀螺影响的研究。建立了Y波导温致半波电压特性对基于宽谱光源的谐振式光纤陀螺系统标度因素的影响规律模型,模型表明:Y波导调制器的温致半波电压特性会导致基于宽谱光源的谐振式光纤陀螺系统的标度因素发生变化。搭建了用于宽谱光源的Y波导调制器半波电压测试系统,系统测试精度达1 mV。实验测试了全温范围内Y波导的温致半波电压特性在基于宽谱光源的谐振式光纤陀螺系统中的影响,测试结果表明:Y波导调制器的半波电压与温度呈线性负相关;Y波导调制器的温致半波电压特性导致基于宽谱光源的谐振式光纤陀螺系统的标度因素的最大相对变化误差为1 266.01×10^(-6)。

依福地平对猪流行性腹泻病毒的抑制作用研究

猪流行性腹泻病毒(porcine epidemic diarrhea virus, PEDV)是猪流行性腹泻(PED)的病原。本研究通过CCK-8、细胞ELISA、Western blot、时间过程分析、药物抑制病毒吸附和入胞试验,探究了依福地平对PEDV的抑制作用。结果表明,依福地平在20μmol/L浓度范围内,对Vero-E6和Marc-145细胞毒性较低;Western blot结果表明,依福地平能够显著降低宿主细胞中PEDV-N蛋白水平,主要抑制PEDV感染的入胞阶段。研究还发现,依福地平能抑制Ⅰ型单纯疱疹病毒和猪伪狂犬病毒感染宿主细胞,是一类潜在的广谱抗病毒药物。

广谱性金刚石钻头国内外研究现状及发展趋势分析

随地球浅层资源消耗殆尽,资源勘探开发不断向深部进军,所遇地层条件愈加复杂,坚硬致密地层、强研磨性地层等复杂地层条件成为深部钻探的重大阻碍。金刚石钻头广泛应用于地质资源开发,因此对金刚石钻头综合性能要求也随之提高,然而现有的金刚石钻头只能适用于某一地层,需要经常更换,因此,研发地层适用性好、钻进效率高、钻头寿命长的广谱性金刚石钻头是克服深部钻探任务的重要内容。近年来,金刚石钻头发展迅速,在结构、品类与性能等方面都得到了较大提升,同时也存在一定提升空间。本文介绍了近年来广谱性金刚石钻头的研究现状与取得的重要进展,包括钻头结构及胎体性能方面的提升及应用,随后针对现有的广谱性金刚石钻头研究成果,提出了金刚石钻头的研究难题以及未来发展方向。通过本文对广谱性金刚石钻头的发展趋势总结,揭示了金刚石钻头制作技术和应用领域的新型研究方向,对我国油气勘探及矿产资源开发领域广谱性金刚石钻头研究有一定借鉴意义。

高性能宽谱上转换成像发光二极管性能优化

高性能宽谱上转换成像器件在医疗、食品安全、无损检测和国家安全等领域中发挥着重要作用,但现有半导体上转换器件因探测范围窄、上转换效率低而受到限制。为实现更宽谱和高效的上转换,本文通过优化LED结构,显著提升了棘轮上转换器件的性能。改进后的LED发光效率提升了2个数量级,μA量级的驱动电流下即可开启发光,发光光谱更接近规则洛伦兹线型,器件整体面发光均匀性也显著提升。研究明确了性能优化原则,并为未来上转换器件的改进提供了参考方向。

兼抗河北省茎基腐病致病菌小种的小麦种质筛选

发掘小麦种质资源中具有茎基腐病(Fusarium crown rot,FCR)抗性的品种,可以为小麦抗茎基腐病研究和抗病品种选育提供抗病材料。首先,以黄淮麦区小麦茎基腐病高致病力假禾谷镰刀菌(Fusarium psendograminearum,Fp)菌株WZ-8A为接种致病菌,利用病情指数(disease index,DI),对来自国内外不同生态区的260份小麦品种进行3次苗期温室小麦茎基腐病抗病鉴定,结果显示,没有免疫和高抗的小麦材料,有中等抗性材料1份(轮选49,DI为16.67)、低抗材料80份、中感材料153份、高感材料26份。随后,以筛选出的具有良好抗性(DI≤27.50)的14份小麦品种为供试材料,分别接种分离于河北省不同地区且具有不同遗传背景的4个小麦茎基腐病致病菌小种,通过苗期抗病性评价获得兼抗多个河北省小麦茎基腐病小种的小麦种质,结果显示,衡Y16观164、农大2011、茶淀红对4个致病菌小种的平均DI较低,综合抗病性较好。衡Y16观164、农大2011、茶淀红可以为河北省小麦茎基腐病研究和抗病品种选育提供抗病材料。

呼吸道病毒混合感染的临床特征和研究进展

由于呼吸道病毒具有相似的组织嗜性、传播途径、易感人群,当多种呼吸道病毒叠加流行时,常发生混合感染。特定呼吸道病毒之间的混合感染会引发更为严重的疾病后果,增加临床治疗的难度。目前,病毒混合感染的致病机制仍不明确,也缺少针对呼吸道病毒混合感染的有效防治策略。在宿主细胞内,不同病毒间的相互作用存在正向促进或负向抑制的差异,相同的信号通路和宿主因子也可能参与了多个病毒的感染周期。本文综述了呼吸道病毒混合感染的临床研究进展及其危害,总结了呼吸道病毒混合感染的相互作用关系和致病机制,提出了广谱疫苗和抗病毒药物在防治病毒混合感染方面的应用前景,为呼吸道病毒混合感染的防治提供了可参考的科学见解。