旅游管理信息系统设计运行中存在的问题及对策

介绍了旅游管理信息系统的特点,分析了该系统在设计、运行中出现的安全性、实效性和规范性等方面的问题,并给出了相应的解决对策。     

Highly efficient genome editing in Xanthomonas oryzae pv. oryzae through repurposing the endogenous type I-C CRISPR-Cas system

Efficient and modular genome editing technologies that manipulate the genome of bacterial pathogens will facilitate the study of pathogenesis mechanisms. However, such methods are yet to be established for Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of rice bacterial blight. We identified a single type I-C CRISPR-Cas system in the Xoo genome and leveraged this endogenous defence system for high-efficiency genome editing in Xoo. Specifically, we developed plasmid components carrying a mini-CRISPR array, donor DNA, and a phage-derived recombination system to enable the efficient and programmable genome editing of precise deletions, insertions, base substitutions, and gene replacements. Furthermore, the type I-C CRISPR-Cas system of Xoo cleaves target DNA unidirectionally, and this can be harnessed to generate large genomic deletions up to 212 kb efficiently. Therefore, the genome-editing strategy we have developed can serve as an excellent tool for functional genomics of Xoo, and should also be applicable to other CRISPR-harbouring bacterial plant pathogens.     

HopAZ1, a type III effector of Pseudomonas amygdali pv. tabaci,induces a hypersensitive response in tobacco wildfire-resistant Nicotiana tabacum ‘N509’

Pseudomonas amygdali pv. tabaci (formerly Pseudomonas syringae pv. tabaci; Pta) is a gram-negative bacterium that causes bacterial wildfire disease in Nicotiana tabacum. The pathogen establishes infections by using a type III secretion system to inject type III effector proteins (T3Es) into cells, thereby interfering with the host__s immune system. To counteract the effectors, plants have evolved disease-resistance genes and mechanisms to induce strong resistance on effector recognition. By screening a series of Pta T3E-deficient mutants, we have identified HopAZ1 as the T3E that induces disease resistance in N. tabacum ‘N509’. Inoculation with the Pta ∆hopAZ1 mutant did not induce resistance to Pta in N509. We also found that the Pta ∆hopAZ1 mutant did not induce a hypersensitive response and promoted severe disease symptoms in N509. Furthermore, a C-terminal truncated HopAZ1 abolished HopAZ1-dependent cell death in N509. These results indicate that HopAZ1 is the avirulence factor that induces resistance to Pta by N509.     

Improvement of glycine biosynthesis from one-carbon compounds and ammonia catalyzed by the glycine cleavage system in vitro

Glycine cleavage system (GCS) plays a central role in one-carbon (C1) metabolism and receives increasing interest as a core part of the recently proposed reductive glycine pathway (rGlyP) for assimilation of CO₂ and formate. Despite decades of research, GCS has not yet been well understood and kinetic data are barely available. This is to a large degree because of the complexity of GCS, which is composed of four proteins (H, T, P, and L) and catalyzes reactions involving different substrates and cofactors. In vitro kinetics of reconstructed microbial multi-enzyme glycine cleavage/synthase system is desired to better implement rGlyP in microorganisms like Escherichia coli for the use of C1 resources. Here, we examined in vitro several factors that may affect the rate of glycine synthesis via the reverse GCS reaction. We found that the ratio of GCS component proteins has a direct influence on the rate of glycine synthesis, namely higher ratios of P protein and especially H protein to T and L proteins are favorable, and the carboxylation reaction catalyzed by P protein is a key step determining the glycine synthesis rate, whereas increasing the ratio of L protein to other GCS proteins does not have significant effect and the ratio of T protein to other GCS proteins should be kept low. The effect of substrate concentrations on glycine synthesis is quite complex, showing interdependence with the ratios of GCS component proteins. Furthermore, adding the reducing agent dithiothreitol to the reaction mixture not only results in great tolerance to high concentration of formaldehyde, but also increases the rate of glycine synthesis, probably due to its functions in activating P protein and taking up the role of L protein in the non-enzymatic reduction of H_ox to H_red. Moreover, the presence of some monovalent and divalent metal ions can have either positive or negative effect on the rate of glycine synthesis, depending on their type and their concentration.     

钼靶和超声检查在乳腺癌临床诊断的准确性的比较分析

摘要 目的：比较与分析钼靶和超声检查在乳腺癌临床诊断的准确性。方法：2018年8月到2021年1月选择在本院进行诊治的乳腺肿瘤患者110例作为研究对象,所有患者都给予钼靶和超声检查,记录影像学特征并判断诊断价值。结果：在110例患者中,病理诊断为乳腺良性肿瘤76例、乳腺癌34例。恶性组钼靶的分叶征、钙化、大角征、毛刺征等比例高于良性组,病灶大小也高于良性组(P<0.05)。恶性组超声的形态不规则、边缘不光整、高回声晕、回声衰减、微钙化等比例高于良性组(P<0.05)。钼靶乳腺影像报告及数据系统(Breast imaging report and data system,BI-RADS)判断为乳腺良性肿瘤72例,乳腺癌38例;超声BI-RADS判断为乳腺良性肿瘤75例,乳腺癌35例,钼靶鉴别诊断乳腺癌的敏感性为93.4%,特异性为97.1%,准确性为94.5%;超声鉴别诊断乳腺癌的敏感性为98.7%,特异性为100.0%,准确性为99.1%。多因素logistic回归分析显示病灶大小、分叶征、回声衰减、毛刺征为导致误诊的重要因素(P<0.05)。结论：乳腺癌在钼靶和超声检查中都有明显的征象特征,超声诊断的准确性更高,病灶大小、分叶征、回声衰减、毛刺征为影响诊断效果的很重要因素。     

研究报告：缓激肽上调豚鼠肠道黏膜下神经丛环氧合酶2的表达

目的缓激肽和缓激肽B2受体在肠神经系统中起重要作用。缓激肽通常参与肠道的炎症反应和神经保护,这种作用取决于缓激肽诱导前列腺素的形成。环氧合酶1 (COX1)和环氧合酶2 (COX2)催化花生四烯酸转化为前列腺素。本研究旨在探讨缓激肽刺激对豚鼠肠神经前列腺素E2 (p GE2)释放和COX2表达的影响及信号机制。方法本文通过免疫荧光检测肠神经细胞中COX2与神经细胞标志物Anti-Hu和ch AT的表达;采用PCR及蛋白质印迹(Western blot)检测不同条件下缓激肽刺激对COX2表达的影响;使用缓激肽B1受体的选择性拮抗剂Leu-8和B2受体的选择性拮抗剂HOE-140,研究缓激肽影响COX2表达的信号机制;利用COX2选择性拮抗剂NS398和COX1拮抗剂FR12207,观察COX2在缓激肽诱导p EG2释放的作用。结果 COX2与神经细胞标志物Anti-Hu和ch AT在肠神经细胞上共同表达,缓激肽可通过B2受体诱导肠神经细胞COX2的表达。缓激肽刺激引起的肠神经细胞p GE2的释放与COX2表达升高密切相关。结论缓激肽通过B2R影响肠道黏膜下神经丛COX2的表达,肠道缓激肽...     

不同运动方式对2型糖尿病大鼠骨骼肌Rab5蛋白及糖代谢的影响*

目的: 探讨持续运动和间歇负重运动对2型糖尿病(T2DM)骨骼肌组织细胞形态、骨骼肌Rab5 mRNA及蛋白表达、骨骼肌糖代谢的影响。方法: SD大鼠选取8只为空白对照组(CR),其他采用高脂高糖饲料喂养6周后,腹腔注射STZ(35 mg/kg)构建T2DM模型。选取24只T2DM分3组(n=8),分别为:T2DM模型组(DRM)、持续运动组(DCRE)、间歇负重运动组(DWRE)。持续运动方案:为前1～2 周准备活动15 m/min(10 min)、运动20 m/min(40 min)、整理活动15 m/min(10 min),后3～8周为 18 m/min(10 min)、25 m/min(40 min)、15 m/min(10 min);间歇负重运动方案:采用负荷重量为15%(1～2周)、30%(3～4周)、45%(5～8周),运动均为15 m/min(5 min),共12组,组间休息3 min。8周后,通过HE观察骨骼肌病理形态变化,qRT-PCR检测骨骼肌Rab5、葡萄糖转运酶4(GLUT4)的mRNA表达,免疫荧光组化技术及Western blot检测骨骼肌Rab5的蛋白表达,ELISA检测血浆Rab5和糖化血红蛋白(GHb)浓度。结果: 相比CR,DRM存在骨骼肌病理损伤,骨骼肌Rab5mRNA及蛋白表达、GLUT4 mRNA表达均降低(P＜0.01),血浆Rab5和GHb均显著升高(P＜0.01);与DRM比较, DCRE、DWRE骨骼肌病理损伤均显著减轻,骨骼肌Rab5 mRNA及蛋白表达、GLUT4 mRNA表达均升高(P＜0.05,P＜0.01),血浆Rab5和GHb降低(P＜0.01);DCRE与DWRE组间均无统计学差异(P＞0.05)。结论: 2种运动方式均能改善2型糖尿病大鼠骨骼肌病理损伤,并可通过提高骨骼肌Rab5基因和蛋白表达从而增强 GLUT4转运能力,缓解骨骼肌糖代谢稳态失衡,但2种运动方式对骨骼肌Rab5蛋白和糖代谢的影响无明显差异性。     

我国省域基础设施投入对社会-生态系统脆弱性的影响

基础设施投入对社会经济或生态系统的影响已被广泛讨论,但对社会-生态系统(SES)的作用如何仍不得而知。本研究梳理了基础设施投入对SES脆弱性的影响机理,并在核算省域人均基础设施资本存量及综合评估SES脆弱性的基础上,采用空间自相关与空间计量模型实证分析了我国省域基础设施投入对SES脆弱性的作用。结果表明: 2004—2017年,我国省域人均基础设施投入水平显著提高,且呈北高南低、东西高中间低的空间分布格局;省域SES脆弱性也在不断改善,却表现出由东向西逐步恶化的分布特点;我国省域人均基础设施投入与SES脆弱性具有空间正相关性,存在聚集性分布特征;两者呈倒U型曲线关系,即早期适量基础设施投入会降低SES脆弱性,而过度投入则会导致SES脆弱性逐步增加。本研究揭示了基础设施投入对SES脆弱性的影响机理与动态特点,可为宏观层面统筹协调基础设施建设与SES脆弱性治理提供理论与决策支持。     

西双版纳热带季雨林通量分配及能量平衡问题北大核心CSCD

为了探讨我国西双版纳热带季雨林的能量分配和平衡问题,利用涡度相关系统和常规气象仪器的连续监测结果,分析了不同季节的能量通量特征和闭合特点。结果表明,西双版纳热带季雨林全年的净辐射、潜热通量、显热通量、土壤热通量和热储存量分别是4546.07、2453.24、492.22、-10.47和45.93 MJ/m^(2),土壤为热源,潜热年总值占净辐射的54.0%,显热占10.8%,能量以蒸发散为主要的耗损形式。辐射和能量有明显的日变化和季节动态,各能量分量的日变化几乎都呈白天高夜间低的单峰趋势,反照率整体为0.10~0.12,波动不大;波文比季节差异明显,为0~0.8。热带季雨林的全年闭合度为0.67,未考虑热储量时,闭合度为0.51~0.79,考虑热储量为0.53~0.80。可见,在林冠茂密的热带季雨林中,热储量对能量闭合度的贡献不大,忽略热储量并不是导致能量不闭合的主要原因。