利用nested PCR-DGGE技术分析江苏啤酒大麦真菌群落结构

为了探索真菌群落对啤酒大麦麦芽的影响,首先要了解啤酒大麦真菌群落结构。文中采用9种不同方法提取了啤酒大麦总DNA,利用嵌套聚合酶链式反应-变性梯度凝胶电泳(nested PCR-DGGE)技术,分析了啤酒大麦真菌群落结构,明确了啤酒大麦中优势真菌种属信息。不同DNA提取方法,nested PCR-DGGE分析结果有显著差异。啤酒大麦中的主要真菌为Cochliobolus sativus、Alternaria alternata、Fusarium sporotrichioides、Coniothyrium fuckelii、Aspergillus sp.和Saccharomyces cerevisiae等子囊菌门真菌以及Sporobolomyces roseus、Cryptococcus magnus和Entorrhiza fineranae等担子菌门真菌。该研究丰富了对啤酒大麦真菌群落结构的认识,同时也证明nested PCR-DGGE技术是一种能够快速有效地研究啤酒大麦真菌群落结构的技术。

Analysis of bacterial community structures in two sewage treatment plants with different sludge properties and treatment performance by nested PCR-DGGE method

The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis （DGGE） of nested polymerase chain reaction （nested PCR） amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated sludge samples were amplified using the extracted genomic DNA before the PCR products were loaded on the same DGGE gel for bacterial community analysis. Ammonia-oxidizing bacterial and actinomycetic community analysis were also carried out to investigate the relationship between specific population structures and system or sludge performance. The two plants demonstrated a similarity in bacterial community structures of raw sewage and activated sludge, but they had different effluent populations. Many dominant bacterial populations of raw sewage did not appear in the activated sludge samples, suggesting that the dominant bacterial populations in raw sewage might not play an important role during wastewater treatment. Although the two plants had different sludge properties in terms of settleability and foam forming ability, they demonstrated similar actinomycetic community structures. For activated sludge with bad settling performance, the treated water presented a similar DGGE pattern with that of activated sludge, indicating the nonselective washout of bacteria from the system. The plant with better ammonium removal efficiency showed higher ammonia-oxidizing bacteria species richness. Analysis of sequencing results showed that the major populations in raw sewage were uncultured bacterium, while in activated sludge the predominant populations were beta proteobacteria.

Design and assembly of a nested imaging X-ray telescope for the Hot Universe Baryon Surveyor mission

The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progress in the design and construction of nested X-ray telescopes which were designed to use a three-stage conic-approximation type assembly to simplify the manufacturing process. The mirror substrate is made using the thermal glass slumping method, with mirrors characterized by a root-mean-square roughness of 0.3 nm, with expected high reflectivity and good thermal stability. We also discuss methods of telescope construction and conduct a deformation analysis of the manufactured mirror. The in situ measurement system program is developed to guide the telescope assembly process.

Nested Levels of Hybrid Cryptographical Technique for Secure Information Exchange

Data security is a very important part of data transmission over insecure channels connected through high-speed networks. Due to COVID-19, the use of data transmission over insecure channels has increased in an exponential manner. Hybrid cryptography provides a better solution than a single type of cryptographical technique. In this paper, nested levels of hybrid cryptographical techniques are investigated with the help of Deoxyribonucleic Acid (DNA) and Paillier cryptographical techniques. In the first level, information will be encrypted by DNA and at the second level, the ciphertext of DNA will be encrypted by Paillier cryptography. At the decryption time, firstly Paillier cryptography will be processed, and then DAN cryptography will be processed to get the original text. The proposed algorithm follows the concept of Last Encryption First Decryption (LEFD) at the time of decryption. The computed results are depicted in terms of tables and graphs.

Seasonal increase in nest defense,but not egg rejection,in a cuckoo host

The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.

A Nested Case-Control Study to Explore the Association between Immunoglobulin G N-glycans and Ischemic Stroke

Objective This study prospectively investigates the association between immunoglobulin G(IgG)N-glycan traits and ischemic stroke(IS) risk.Methods A nested case-control study was conducted in the China suboptimal health cohort study,which recruited 4,313 individuals in 2013–2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. Ig G N-glycans in baseline plasma samples were analyzed.Results A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks(GPs) were separated from Ig G N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference,obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men(FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio(OR) = 0.92, 95% confidence interval(CI): 0.87–0.97;G1n: OR = 0.74, 95% CI: 0.63–0.87;G0n: OR =1.12, 95% CI: 1.03–1.22). However, these associations were not found among women.Conclusion This study validated that altered Ig G N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.

Use the Power of a Genetic Algorithm to Maximize and Minimize Cases to Solve Capacity Supplying Optimization and Travelling Salesman in Nested Problems

Using Genetic Algorithms (GAs) is a powerful tool to get solution to large scale design optimization problems. This paper used GA to solve complicated design optimization problems in two different applications. The aims are to implement the genetic algorithm to solve these two different (nested) problems, and to get the best or optimization solutions.

Reduced risk of dementia in patients with type 2 diabetes mellitus using Chinese herbal medicine:A nested case-control study

BACKGROUND Dementia is a prevalent condition in type 2 diabetes mellitus(T2DM)patients.While Chinese herbal medicine(CHM)is often employed as complementary therapy for glycemic control,its effect in controlling likelihood of dementia has not yet been fully elucidated.AIM To compare the risk of dementia between T2DM patients with and without CHM treatment.METHODS We undertook a nested case-control study and obtained data on patients 20-70 years of age who received medical care for T2DM between 2001 and 2010 from the National Health Insurance Research database in Taiwan.Cases,defined as those with dementia that occurred at least one year after the diagnosis of T2DM,were randomly matched to controls without dementia from the study cohort at a 1:1 ratio.We applied conditional logistic regression to explore the associations between CHM treatment and dementia.RESULTS A total of 11699 dementia cases were matched to 11699 non-dementia controls.We found that adding CHM to conventional care was related to a lower risk of dementia[adjusted odds ratio(OR)=0.51],and high-intensity CHM treatment was associated with an adjusted OR of 0.22.CONCLUSION This study shows that the cumulative CHM exposure was inversely associated with dementia risk in an exposureresponse manner,implying that CHM treatment may be embraced as a disease management approach for diabetic patients to prevent dementia.

Nest decoration:Black feathers prevent Crested Mynas from nest usurpation

Nests are important structures for birds to raise their offspring and for signaling.Many birds incorporate feathers into the nest,since feathers were traditionally thought to serve the function of insulation.Hypotheses in recent years have considered that some birds place feathers in conspicuous locations in the nest for decoration to trigger a fear response in the competitors.In this study,we investigated whether decorative feathers could deter nest usurpation by Crested Mynas(Acridotheres cristatellus)by manipulating nest box contents.The results revealed that Crested Mynas preferred black feathers to white feathers as decorations and occupied nest boxes decorated with black feathers significantly less than those decorated with white feathers,suggesting that black decorative feathers in the nest could be more effective in preventing nest usurpation by Crested Mynas and that white decorative feathers may have other functions.The black feathers in the nest are prominently placed at the edge of the nest to convey the message that“this nest is occupied”or“the owner of this nest has been preyed upon”to visitor Crested Mynas,thus effectively preventing them from usurping the nest at a later stage.

基于PCR-DGGE技术分析浓香白酒窖泥梭菌多样性

窖泥是浓香型白酒酿制过程中最主要的微生物源,窖泥中微生物的类型、丰度、新陈代谢活动等均对浓香型白酒品质产生很大的影响。为探究窖泥中梭菌微生物的多样性,利用窖泥理化结合聚合酶链式反应-变性梯度凝胶电泳技术对10个窖泥样品中的梭菌群落及变化规律进行研究。结果表明,所选10个窖泥的理化参数均符合优质窖泥指标要求;在微生物层面,窖泥中检测到的梭菌在属水平上有:嗜碱菌属、丁酸弧菌属、梭菌属、喜热菌属、瘤胃梭菌属、粪球菌属、沉淀杆菌属(Sedimentibacter)、钙原杆菌属(Caldicoprobacter)、温带菌(Tepidimicrobium)、梯氏菌(Tissierella)、孢子菌(Sporanaerobacter)、硫酸盐还原菌属、鲁替孢菌属和梭状芽胞杆菌(Clostridiisalibacter)等,这些菌是优质窖泥的重要指示菌,可知窖泥中含有极其丰富的酿酒功能菌。揭示了可能在白酒酿造中起关键作用的梭菌菌群,在分子水平上为研究浓香型白酒提供了理论依据。

Habitat preferences and nest site selection by sympatric populations of Middle Spotted Woodpecker(Dendrocoptes medius) and Syrian Woodpecker(Dendrocopos syriacus) in natural mountain forests of Southwest Iran

We examined habitat preferences and nesting requirements of sympatric populations of Middle Spotted Woodpecker(Dendrocoptes medius) and Syrian Woodpecker(Dendrocopos syriacus).We carried out our study in 2015–2018 in natural mountain forests of Southwest Iran.We compared selected features of nesting,territory,and outside territory tree stands of the studied woodpeckers.The Middle Spotted Woodpecker occupied only oak forests,but the Syrian Woodpecker inhabited heterogenic forests that included the preferred tree of this species,the Mount Atlas Mastic.We recorded that in the breeding territories of the Middle Spotted Woodpecker,a greater area covered by tree crowns,as well as a larger number of trees,and a larger trunk basal area were observed in comparison to the territories occupied by the more plastic Syrian Woodpecker.Different habitat preferences demonstrated by both species could be a result of the selection of tree stands that provide the necessary food resources for each woodpecker species.Adaptation of Syrian Woodpecker to use heterogenic forest stands including tree species that produce fruits and as Mount Atlas Mastic trees,which likely allowed this species to colonise in Asia and Europe non-forest tree stands as orchards or gardens.Our results showed that poor tree condition and large tree trunk dimensions had a positive impact on the selection of nesting sites by both species.The presence of trees with large trunk dimensions was associated with multiple years of use of woodpecker breeding sites in the studied forests.Maintaining habitats in suitable condition for both studied woodpeckers can be achieved by preserving natural forests in the mountain regions of Iran.

Implementation of a Nesting Repair Technology for Transportation Pipeline Repair

Filling methods in the mining industry can maximize the recovery of mineral resources and protect the underground and surface environments.In recent years,such methods have been widely used in metal mines where pipeline transportation typically plays a decisive role in the safety and stability of the entirefilling system.Because thefilling slurry contains a large percentage of solid coarse particles,the involved pipeline is typically eroded and often damaged during such a process.A possible solution is the so-called nesting repair technology.In the present study,nesting a 127 mm outer diameter pipeline in 151 mm inner diameter borehole is considered to meet the repair objective.First,by using the rheological theory,the pipeline transmission resistance and self-flow conveying range are calculated under different working conditions.It is shown that the pipeline transmission resistance is larger when the inner diameter of casing is 80 mm,and the limitflow rate of vertical pipeline self-flow is 120 m^(3)/h;moreover,when the pipeline diameter is 100 mm and theflow rate is 140 m^(3)/h,the self-flow conveying can be satisfied in most of the underground−455 m stage.Accordingly,a plan is presented for the nesting repair strategy,based on the installation of a drill bit under the casing and lowering the casing into the borehole as if it were a drill pipe.Finally,the outcomes of such a strategy are verified.Thefillingflow rate range using the new pipelines is found to be in the range from 188.60 to 224.39 m^(3)/h,and its averagefillingflow rate reaches 209.83 m^(3)/h when conveying 2319.6 m long-distance quarry.

Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) prefer shells for nesting:A field experiment

Shorebird populations are declining worldwide,mainly due to human disturbances and loss of coastal wetlands.However,supratidal habitats as saltpans could play a role in buffering human impact.Saltpans have shown to be important as feeding or breeding sites of some shorebird species.A potential conservation strategy to increase shorebird populations in saltpans is to manipulate the cues that birds use to select optimal breeding habitat.Here it is hypothesized that shorebirds are attracted to bivalve shells due to the advantages they offer.Following this hypothesis,we supplemented a restored saltpan in 2019 and 2021 with bivalve shells,expecting an increase in the number of breeding birds’ nests.More than 75% of Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) nests were found in patches with shells in both years.The best model for both species indicates that the presence of shells is the factor that most correlates with the location of nests.The probability of choosing one place over another to settle their nest increases in areas with an abundance of shells,double in the case of the Kentish Plover and triple in the case of the Little Tern.The result of this study may constitute a valuable tool for attracting birds to restored saltpans and could contribute to the success of expensive restoration projects where time is usually a constraint.

应用PCR及Nested-PCR技术检测柑橘黄龙病病原研究

以采自田间和广东省农业科学院果树研究所防虫隔离网室内嫁接并感染黄龙病的5个柑橘品种叶片为材料,以草本指示植物长春花(Catharanthusroseas)和木本指示植物柑(CitrusreticulataBlanco)鉴定为基础,采用改良的CTAB法提取总DNA,在此基础上进行常规PCR与NestedPCR检测,并对特异目的片段进行克隆、测序。试验证明NestedPCR比常规PCR的灵敏度更高。这两种方法均可以检测出未显症的黄龙病材料,但NestedPCR可以在木本指示植物嫁接后40d左右、草本指示植物摩擦接种1个月左右检测到病原;而常规PCR在木本植物嫁接后60d左右、草本植物摩擦接种近2个月左右才能检测到病原。常规PCR所能检测到的最低DNA的量为pg数量级;NestedPCR检测病原DNA灵敏度约为常规PCR的104倍。

广西砂糖橘黄龙病亚洲种的Nested-PCR检测

【目的】利用柑橘黄龙病病原亚洲种16S rDNA序列的特异引物检测疑似黄龙病的砂糖橘叶片样品,为砂糖橘黄龙病的综合防控提供理论依据。【方法】选取采自广西9市17个采样点的214份疑似黄龙病及无症状砂糖橘叶片样品,用试剂盒法提取叶脉基因组DNA,采用柑橘黄龙病亚洲种16S rDNA特异引物进行PCR扩增,扩增结果在1%琼脂糖凝胶电泳上检测,统计待检样品柑橘黄龙病病原菌亚洲种的带菌率。【结果】对214份样品的Nested-PCR扩增结果,部分样品可得到1160 bp左右的特异条带,与预期大小相符但条带明暗不同。来自广西9市17个采样点的砂糖橘叶片样品均检测出黄龙病亚洲种病原,平均检出率均在66.0%以上,其中检出率最高的是来自东兴市的样品,检出率为100.0%,检出率最低的是来自南宁市的样品,检出率为66.9%;斑驳、缺素型黄化、叶脉黄化、小叶和无症状叶片样品中均可检测出黄龙病亚洲种。【结论】Nested-PCR技术具有灵敏度高、特异性强的特点,能够快速、准确检测出各种症状样品的黄龙病病原,可用于柑橘黄龙病的早期诊断。

大豆油中转基因成分的Nested PCR和Semi-nested PCR检测方法研究

对大豆油中DNA提取方法进行了研究,结果表明CTAB、SDS和Wizard试剂盒提取大豆油DNA均具有良好的效果。利用nested PCR和semi-nested PCR检测大豆(Roundup Ready)油中的转基因成分发现,该方法能够检测到大豆原油中的Lectin基因(112bp)、CaMV35S基因(147bP)和CP4-EPSPS基因(205bp),检测灵敏度达到10-6ng/μl;但该方法未能从人豆成品油(一级)中扩增到上述基因,当中的转基因成分DNA含量低于10-12ng/μl。

RP/SP融合数据的Mixed Logit和Nested Logit模型估计对比

分析了RP/SP(revealed preference/stated preference)融合数据对交通行为研究的重要性,通过实际调查的RP/SP融合数据,对比了用Mixed Logit和Nested Logit模型的估计结果.得出了以下结论:RP/SP融合数据中,有时同类型交通方式的关联性要比RP和SP数据之间的关联性强,应用不同的Nested Logit模型分层方法进行估计对比;Mixed Logit考虑了个体的异质性,假定参数为随机分布,同时体现了RP/SP数据的关联性和同类型交通方式的关联性,能够得到更好的参数估计结果;Mixed Logit模型能更现实地反映不同交通方式使用者对时间和费用敏感性的不同(时间价值的不同),体现小汽车使用者比公共交通使用者具有更高时间价值的现实情况.

基于Nested Logit模型的铁路旅客客运产品选择研究

通过成都—武汉既有线出行旅客的问卷调查,以及样本数据的归纳分析,对旅客客运产品选择行为特征进行描述.基于随机效用最大化理论,以乘车方式与客运产品作为选择肢,旅客主体、出行特性及列车服务特性的各项指标作为效用变量,构建了乘车方式位于上层、客运产品位于下层的Nested Logit模型.模型的上下层参数标定结果表明,旅客的收入状况、出行目的、出行距离、列车票价及运行时间对其乘车方案选择具有显著影响,旅客的年龄、出行费用来源、收入状况、出行距离,以及列车票价、运行时间对其客运产品选择具有显著影响.模型能较为准确地反映铁路客运产品的实际需求,从而为其合理设计与调整提供理论依据.

应用nested和touch down PCR技术分离牦牛CAPN1大亚基基因EST

钙激活中性蛋白酶1(CAPN1)基因是影响肉嫩度的侯选基因。根据GeneBank中已公布的CAPN1基因cDNA序列设计同源PCR引物,通过RT,nested和touch-downPCR技术从牦牛肌肉组织总RNA中分离目的序列,与pGEM-T-easy载体连接后转化DH5α感受态菌株,通过PCR扩增、限制性酶切和测序分析鉴定阳性克隆。分离到的基因片段为牦牛CAPN1大亚基的部分编码序列,在GeneBank中的注册号为AY197555,与奶牛、人、食蟹猴、小鼠、绵羊以及大鼠相应序列的同源性分别为98%,89%,89%,83%,96%和81%,在不同物种之间具有较强的保守性。CAPN1基因EST的分离为进一步研究牦牛CAPN1基因奠定了基础。此研究表明,在总RNA质量不理想的情况下,同时采用这2种技术可以较大限度地获取目的序列。

基于Nested-Logit模型的经济圈交通方式划分方法研究

在分析经济圈交通方式选择影响因素的基础上,利用出行费用、出行时间和舒适性等指标作为广义费用函数的主要构成属性,建立了基于Nested-Logit模型的经济圈交通方式划分方法.并采用出行疲劳恢复时间来描述不同交通方式出行的舒适程度,然后用时间价值的计算方法求得疲劳恢复时间的价值.Nested-Logit模型是在一般多项Logit模型基础上的一种改进模型,考虑了各交通方式之间的相关性,对具有相似性的交通方式进行了分类,因此该模型更接近实际情况,相对合理.同时通过分析这两种模型的内在关系,提出了一种求解Nested-Logit模型的方法,该方法程序化强,便于应用.最后以长三角经济圈部分城市之间的交通方式划分作为实例,说明了该方法有效可行.