镉胁迫对2种油菜土壤真菌群落的影响

[背景] 人类活动引起的农田重金属污染已成为严重的环境问题。镉（Cd）是最具毒性的重金属之一,能对人体和生态系统构成威胁。[目的] 研究不同浓度镉处理对2种油菜（甘蓝型油菜和芥菜型油菜）的土壤（根际和非根际）真菌群落的影响,为镉的生物修复和健康风险评估提供理论基础。[方法] 对2种油菜土壤（根际和非根际）真菌转录间隔区（Internal Transcribed Spacer,ITS）进行高通量测序,分析镉对根际和非根际土壤真菌群落的影响。[结果] 镉胁迫改变了土壤真菌群落的组成和结构,但对2种油菜土壤真菌群落的α多样性几乎无显著影响。土壤镉浓度和生物量与2种油菜根际土壤真菌群落显著相关,芥菜型油菜非根际土壤真菌群落也与镉污染浓度显著相关。土壤真菌分子生态网络也受到镉污染的影响,甘蓝型油菜根际土壤网络稳定性降低,共生关系减少。甘蓝型油菜非根际土壤网络稳定性升高,但共生关系减少。芥菜型油菜的根际和非根际土壤的网络稳定性升高,而且共生关系增多。[结论] 镉污染会影响土壤系统中的本土真菌群落,从而可能进一步改变土壤的生态系统功能。     

磁共振检查对复杂性肛瘘手术治疗患者的指导价值及术后复发的危险因素分析

目的:探讨磁共振成像技术(MRI)对复杂性肛瘘诊断和术前评估的指导意义及术后复发的危险因素。方法:前瞻性选取2015年6月至2017年12月到我院诊断并接受手术治疗的359例复杂性肛瘘患者,将其随机分为观察组182例和对照组177例。对照组患者术前未行MRI检查,术中行亚甲蓝染色指导手术治疗。观察组术前行MRI检查,术中给予亚甲蓝染色结合术前评估行手术治疗,以术中探查结果为金标准,统计MRI术前检查复杂性肛瘘的准确率,Kappa检验评估MRI检查结果与术中探查结果的一致性,经1-2年的随访统计所有患者复发情况,单因素和多因素Logistic回归分析术后复发的危险因素。结果:观察组术中探查共发现瘘管内口281个,合并肛周脓肿57例,多发瘘管及支管151例,MRI术前检查瘘管内口、合并肛周脓肿、多发瘘管及支管的准确率分别为98.22%(276/281)、85.96%(49/57)、96.03%(145/151),观察组中MRI结果与术中探查结果对患者Parks分型通过一致性检验显示,两结果一致性较好(k=0.890,P=0.001)。单因素分析结果显示,肛瘘位置、内口位置、合并肛周脓肿、既往肛瘘手术史及术前是否行MRI检查均会影响复发率(均P0.05),Logistic回归多因素分析显示,术前未进行MRI检查、高位肛瘘、内口位于后正中线、既往肛瘘手术史是复杂性肛瘘术后复发的危险因素(均P0.05)。结论:MRI检查复杂性肛瘘能够术前明确瘘管及内口数量,可较为精确地识别瘘管Parks分型,有助于提高手术疗效,合并肛周脓肿、术前未进行MRI检查、高位肛瘘、内口位于后位、既往肛瘘手术史是复杂性肛瘘术后复发的危险因素。     

New metabolites,sarcopodinols A and B,isolated from deep-sea derived fungal strain Sarcopodium sp. FKJ-0025

Fungal strain FKJ-0025 was isolated from deep-sea sediment collected at the Wakamiko Caldera in Kagoshima Bay (water depth: 200 m). The fungal strain FKJ-0025 was identified as the genus Sarcopodium based on its morphology and internal transcribed spacer (ITS) sequence. Two new compounds, designated sarcopodinols A (1) and B (2), were isolated together with the known compound SF-227 (3).     

rDNA ITS序列在ACCC真菌鉴定中的应用

【目的】真菌无处不在,并与人类生活紧密相关。真菌的鉴定是科学研究和资源开发利用的基础。本研究从中国农业微生物菌种保藏管理中心(ACCC)随机选取已经定名的112株库藏真菌菌株作为实验材料,通过DNA测序,评估核糖体DNA内转录间隔区(rDNA ITS)序列在真菌属级鉴定上的应用。【方法】采用真菌DNA条形码rDNA ITS的序列测定和在GenBank中查寻比对的方法,对这些菌株进行属水平的鉴定复核。【结果】通过研究,供试菌株中有80株的属名与原鉴定相符,同时表明序列中套峰的情况降低与Gen Bank中序列比对的相似性。【结论】rDNA ITS序列测定法可以用于真菌菌株进行属水平的鉴定复核,国家菌种保藏机构应对已入库保藏和即将入库的所有真菌菌株都进行属水平的鉴定复核,并对菌株鉴定结果作审慎处理,原定名的名称及其变更历史应以"曾用名"在数据库中保留。     

A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes

BackgroundHemocyanins are respiratory proteins with multiple functions. In diverse crustaceans hemocyanins can release histidine-rich antimicrobial peptides in response to microbial challenge. In penaeid shrimp, strictly antifungal peptides are released from the C-terminus of hemocyanins.MethodsThe three-dimensional structure of the antifungal peptide PvHCt from Litopenaeus vannamei was determined by NMR. Its mechanism of action against the shrimp pathogen Fusarium oxysporum was investigated using immunochemistry, fluorescence and transmission electron microscopy.ResultsPvHCt folded into an amphipathic α-helix in membrane-mimicking media and displayed a random conformation in aqueous environment. In contact with F. oxysporum, PvHCt bound massively to the surface of fungal hyphae without being imported into the cytoplasm. At minimal inhibitory concentrations, PvHCt made the fungal membrane permeable to SYTOX-green and fluorescent dextran beads of 4 kDa. Higher size beads could not enter the cytoplasm. Therefore, PvHCt likely creates local damages to the fungal membrane. While the fungal cell wall appeared preserved, gradual degeneration of the cytoplasm most often resulting in cell lysis was observed in fungal spores and hyphae. In the remaining fungal cells, PvHCt induced a protective response by the formation of daughter hyphae.ConclusionThe massive accumulation of PvHCt at the surface of fungal hyphae and subsequent insertion into the plasma membrane disrupt its integrity as a permeability barrier, leading to disruption of internal homeostasis and fungal death.General significanceThe histidine-rich antimicrobial peptide PvHCt derived from shrimp hemocyanin is a strictly antifungal peptide, which adopts an amphipathic α-helical structure, and selectively binds to and permeabilizes fungal cells.     

通用PCR法在痰标本真菌检测中的临床应用价值分析

目的:探讨通用PCR法在痰标本真菌检测中的临床应用价值。方法:选择2015年9月至2017年9月本院收治的免疫力低下患者178例作为研究资料,各收集痰标本2份,其中一份用于PCR扩增,另一份经培养后若观察到真菌或可疑菌落,则提取后在此进行PCR扩增测序。比较3种方法对真菌的检出情况、真菌阳性率,与组织病理学结果进行比较,分析3种方法的诊断效能。结果:178份痰标本经平板培养可观察到107份真菌生长,其余71份未见真菌生长。挑取真菌及可疑菌落行PCR结果显示阳性、阴性分别115、63份。对痰标本直接PCR结果显示,阳性、阴性分别124、54份。PCR扩增产物测序结果显示大多是白色念珠菌感染,仅3份是曲霉菌感染。内对照扩增验证结果显示有1份阴性标本存在扩增抑制现象。3种方法的真菌阳性率:直接PCR法痰培养后PCR法痰培养,但组间无显著差异(P0.05)。3种方法诊断效能总体趋势:直接PCR法痰培养后PCR法痰培养,其中直接PCR法与痰培养后PCR法的特异度、准确度均显著高于痰培养法(P0.05),直接PCR法的敏感度显著高于痰培养法(P0.05)。结论:通用PCR法在痰标本真菌检测中的临床应用价值较高,直接PCR具有操作简单、快速等优势。     

矿区复合污染土壤真菌多样性及其对稀土-重金属离子的吸附特征

大量的稀土-重金属通过尾矿坝的浮尘、地表径流和渗滤液排放到周边土壤中,影响了土壤中的微生物群落结构。【目的】分析稀土和重金属复合污染土壤真菌群落结构并分离具有同时吸附稀土和重金属的菌株。【方法】本研究基于ITS基因,采用Illumina-Hiseq测序技术分析了包头稀土尾矿坝周边5份稀土-重金属污染土壤样品和距尾矿区20 km的1份相对未受污染的土壤样品的真菌群落特征,同时采用富集培养法从污染样品中筛选出金属耐性真菌,并对其进行吸附稀土-重金属的特性分析。【结果】群落结构为:在门水平,除了未分类门真菌(unclassified Fungi)外,子囊菌门(Ascomycota)真菌在所有土壤中占比较大(13.5%–90.5%);在纲水平上,除了未分类纲真菌外,粪壳菌纲(Sordariomycetes)真菌在B2 (73.1%)、B3 (28.4%)和B4 (20.8%)的丰度显著高于对照样点C (7.4%),而座囊菌纲(Dothideomycetes)在B5 (11.8%)的丰度明显高于B1 (3.5%);在属水平,除了未分类属,足孢子虫属(Podospora)是C(0.9%)和B3(23.6%)样点的优势种。曲霉属(Aspergillus)、未分类的格孢腔菌目(unclassified Pleosporales)和未分类的戴维迪科(unclassified Davidiellaceae)分别为B1 (3.0%)、B4 (10.5%)和B5(5.8%)的优势种,而蜡蚧属(Lecanicillium)真菌只在B2样点土壤存在且占优(51.6%)。Zn污染对真菌群落结构的影响大于稀土元素污染,且其浓度与优势的未分类真菌相对丰度呈负相关。从污染样品中共分离出6株真菌,它们分属于曲霉属(Aspergillus)(5株)和镰刀霉菌属(Fusarium)(1株)。所有分离菌株对镧(La~(3+))的吸附率均显著高于锌(Zn~(2+)),其中Aspergillus sp. B6-3对La~(3+)和锌Zn~(2+)的吸附率最高,分别为19.7%和3.9%。【结论】该研究为利用真菌去除稀土和重金属以优化生物吸附过程导向的环境生物修复和保护策略提供了机制基础。     

象山港硅藻赤潮过程中真菌群落演替及互作特征

[背景] 近岸海域赤潮的发生能显著改变包括真菌在内的微生物群落组成,进而影响海洋中碳氮元素循环。真菌是海洋中重要的分解者,但赤潮过程对真菌群落的影响少有报道。[目的] 探明赤潮过程对真菌群落的影响,对进一步阐释赤潮对生态系统中物质循环的影响具有重要意义。[方法] 针对2017年春季象山港硅藻赤潮,对真菌内源转录间隔区1（Internally Transcribed Spacer 1,ITS1）序列进行高通量测序,研究赤潮过程中真菌群落响应及共现性特征。[结果] 真菌群落的α多样性指数在赤潮暴发的各阶段差异显著,而且均与磷酸盐、硝酸盐和亚硝酸盐有显著相关性（P<0.05）。子囊菌门（Ascomycota,90.2%）和担子菌门（Basidiomycota,8.27%）是本次硅藻赤潮的优势菌门,其中子囊菌门遍布赤潮暴发的4个阶段;锤舌菌纲（Leotiomycetes,16.1%）和散囊菌纲（Eurotiomycetes,9.3%）是纲水平上的主要优势类群。赤潮暴发过程中硝酸盐、亚硝酸盐、磷酸盐和温度等环境因素的改变,驱动真菌群落组成及结构发生显著变化。Helotiales、Eurotiales、Xylariales、Sacc haromycetales和Agaricostilbales构成了真菌群落共现网络的主体。[结论] 真菌群落在赤潮的各阶段具有显著的演替特征,赤潮藻生消是引起真菌群落演替的主要因素,但是环境因子也扮演着重要角色。赤潮过程中,真菌群落同类群内的互作要强于不同类群间的互作,这对维持群落的稳定性具有重要意义。     

真菌性鼻鼻窦炎发病相关因素及临床特征分析

目的:探究影响真菌性鼻鼻窦炎发病的有关因素,并分析其临床特征。方法:选取在我院就诊的150例真菌性鼻鼻窦炎患者及150例慢性鼻鼻窦炎患者,回顾性分析2组患者的临床资料,将两者进行对照研究,通过多因素Logistic回归分析和检验的方法,对患者的术前资料进行分析,进而探讨影响真菌性鼻鼻窦炎发病的因素及其临床特征。通过真菌特异性六胺银染色的方法,对150例真菌性鼻鼻窦炎患者进行分型。结果:以年龄(x_1)、病程(x_2)、涕血(x_3)、头痛(x_4)、单侧或双侧病变(x_5)和钙化斑(x_6)为变量,获得了真菌性鼻鼻窦炎发病的Logistic回归预测方程:y=-8.714+1.201 x_1+0.497 x_2+4.576 x_3+1.188 x_4+2.697x_5+4.118 x_6,P=exp(y)/[1+exp(y)]。与慢性鼻鼻窦炎的发病情况对比,发现真菌性鼻鼻窦炎的发生多位女性患者,年龄在40岁以上,病程在3年以内,主要症状为头痛和涕血,影像学检查有单侧病变,且有钙化斑出现(P0.05)。在150例真菌性鼻鼻窦炎患者中,慢性侵袭性46例,非侵袭性104例。结论:真菌性鼻鼻窦炎的发病可以通过其相关因素的Logistic回归预测方程进行预测,其临床表现有明显的特征性。     

Design,synthesis and in vitro bactericidal/fungicidal screening of some vanadyl(IV)complexes with mono- and di-substituted ONS donor triazoles

Abstract

A new series of anti-bacterial and anti-fungal mono- and di-substituted triazoles (L¹)–(L⁶) have been synthesized and characterized on the basis of their physical, spectral and analytical data. The ligands (L¹)–(L⁶) on reaction with vanadyl(IV) sulphate led to the formation of vanadyl(IV) metal complexes (1)–(4). The structure of the complexes has been established on the basis of their physical, spectral and elemental analyses data. The synthesized ligands and their vanadyl(IV) complexes have been screened in vitro for anti-bacterial activity against six bacterial species such as, Escherichia coli (ATCC 25922), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (ATCC 27853), Salmonella typhi (ATCC 14028), Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6051) and for in vitro anti-fungal activity against six fungal strains, Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata. The screening results showed the vanadyl complexes to be more bactericidal/fungicidal against one or more bacterial/fungal species. The synthesized compounds were also subjected to brine shrimp bioassay for scrutinizing their cytotoxicity.     

添加毛叶苕子对红壤旱地土壤真菌群落的影响

【目的】长期高强度的连作及大量化肥施用导致红壤旱地退化和土传植物病原菌累积。真菌是农业生态系统中与土壤健康密切相关的微生物。本文通过研究土壤真菌群落的变化,探究施用毛叶苕子对红壤旱地农业生态系统的影响。【方法】采用定量聚合酶链式反应和高通量测序技术,研究红壤旱地真菌群落对单施矿质肥(mineral nitrogen,phosphorus and potassium fertilization,NPK)与矿质肥配施毛叶苕子(mineral nitrogen,phosphorus and potassium fertilization with hairy vetch,NPKG) 2种施肥措施的响应。【结果】与对照NPK相比,NPKG显著提高土壤肥力、花生产量和土壤真菌丰度,降低土壤p H和土壤真菌多样性。不同处理显著改变土壤真菌群落组成。与对照NPK相比,NPKG处理土壤腐生营养型真菌相对丰度显著提高37.42%,花生尾孢菌(Cercospora arachidicola)和可可毛色二孢菌(Lasiodiplodia theobromae) 2种花生病原菌相对丰度分别降低89.11%和8...     

Construction of a prognostic immune signature for lower grade glioma that can be recognized by MRI radiomics features to predict survival in LGG patients

BackgroundThis study aimed to identify a series of prognostically relevant immune features by immunophenoscore. Immune features were explored using MRI radiomics features to prediction the overall survival (OS) of lower-grade glioma (LGG) patients and their response to immune checkpoints.MethodLGG data were retrieved from TCGA and categorized into training and internal validation datasets. Patients attending the First Affiliated Hospital of Harbin Medical University were included in an external validation cohort. An immunophenoscore-based signature was built to predict malignant potential and response to immune checkpoint inhibitors in LGG patients. In addition, a deep learning neural network prediction model was built for validation of the immunophenoscore-based signature.ResultsImmunophenotype-associated mRNA signatures (IMriskScore) for outcome prediction and ICB therapeutic effects in LGG patients were constructed. Deep learning of neural networks based on radiomics showed that MRI radiomic features determined IMriskScore. Enrichment analysis and ssGSEA correlation analysis were performed. Mutations in CIC significantly improved the prognosis of patients in the high IMriskScore group. Therefore, CIC is a potential therapeutic target for patients in the high IMriskScore group. Moreover, IMriskScore is an independent risk factor that can be used clinically to predict LGG patient outcomes.ConclusionsThe IMriskScore model consisting of a sets of biomarkers, can independently predict the prognosis of LGG patients and provides a basis for the development of personalized immunotherapy strategies. In addition, IMriskScore features were predicted by MRI radiomics using a deep learning approach using neural networks. Therefore, they can be used for the prognosis of LGG patients.     

高通量测序分析云南腾冲热海热泉真菌多样性

【目的】本研究揭示云南腾冲热海热泉真菌多样性及群落分布格局,探讨其理化因子对真菌群落结构的影响。【方法】利用Illumina Hi Seq2500高通量测序平台对腾冲热海热泉沉积物宏基因组ITS基因进行测序,并进行生物信息分析。【结果】从5个热泉样品中共检测到343484条有效序列,包括5个真菌门,20个纲,66个目。右姐妹泉(JMQR)、左姐妹泉(JMQL)、蛤蟆嘴泉(M)、桥泉(QQ)及鼓明泉(GMQP)分别以Agaricales、Eurotiales、Capnodiales和Hypocreales等为优势目。在属水平上,共获得365个属,从JMQR中检测到212个属,以裂褶菌属(Schizophyllum)为最优势;从JMQL中挖掘到197个属,以青霉属(Penicillium)为最优势类群;从M和QQ中分别获得222个和270个属,均以枝孢属(Cladosporium)为最优势;从GMQP中发现179个属,以侧齿霉属(Engyodontium)丰度最高。NH4+含量、温度及pH影响不同优势真菌的分布,其中以pH与优势类群(OTU1%)结构变化显著性最高(P=0.05)。【结论】云南腾冲热海高温热泉蕴藏着极其丰富的真菌物种,其不同样品真菌分布具有差异性,pH可能是影响热泉真菌群落分布的重要因素之一。     

鞍旁海绵状血管瘤的MRI诊断及误诊分析

目的:分析鞍旁海绵状血管瘤MR影像特点及误诊原因,提高对该疾病的诊断及鉴别诊断水平。方法:收集我院经手术病理证实的13例鞍旁海绵状血管瘤,术前均行MRI平扫及增强扫描,5例行3D-ASL检查,分析其影像学资料。结果:9例表现为横向哑铃状,鞍旁大,鞍内小,病灶主体位于颈内动脉外侧,颈内动脉海绵窦段被病灶包绕;1例鞍旁与鞍内病灶大小相似,1例病灶主体位于颈内动脉内侧,2例病灶完全位于颈内动脉外侧;7例垂体显示不清,6例垂体受推移;6例T2W I表现为类似脑脊液的极高信号;仅5例行3D-ASL检查,病灶均呈低灌注。误诊9例,其中4例误诊垂体腺瘤,5例误诊脑膜瘤。结论:横向哑铃状、病灶主体位于颈内动脉外侧及T2W I类似脑脊液的极高信号是鞍旁海绵状血管瘤的典型影像特征。对于不典型病变,借助3D-ASL可以减少误诊,充分掌握MRI影像特征及鉴别诊断的要点,对提高临床术前诊断水平具有重要价值。     

68Ga-PSMA-HBED-CC PET/MRI is superior to multiparametric magnetic resonance imaging in men with biochemical recurrent prostate cancer: A prospective single-institutional study

BackgroundThe primary objective was to compare the overall diagnostic performance, presented as detection rate of ⁶⁸Ga-PSMA-HBED-CC positron emission tomography/magnetic resonance imaging (PSMA PET/MRI) versus conventional, multiparametric MRI (mpMRI) in a population of patients with biochemically recurrent prostate cancer. In conjunction with this analysis, secondary objectives included the evaluation of the detection rate stratified by PSA levels and primary treatment modality.MethodsA total of 165 PSMA PET MRI were performed from April 2018 to May 2021, of whom 108 were presenting for biochemical recurrent disease. The PSMA PET vertex to thigh were read by two different board-certified nuclear medicine physicians while the MRI head and neck, chest, abdomen, and pelvis (with dedicated, PI-RADS compliant multiparametric prostate MRI) were read by two board certified diagnostic radiologists.AnalysisPSMA PET/MRI had a higher detection rate than mpMRI when evaluating patients with biochemical recurrence (BCR) with similar results demonstrated when sub-analysis was performed using PSA levels, primary treatment modality, and time since androgen deprivation therapy. Our study also showed PSMA PET/MRI had a higher sensitivity than mpMRI.DiscussionOur findings demonstrate that PSMA PET/MRI is a better imaging modality in the detection of disease in the setting of BCR when compared to MRI alone. Combined utility with PSMA PET/MRI is a powerful tool which can aid in not only the detection of disease, but also guide in treatment planning for prostate cancer patients.     

巨噬细胞膜仿生纳米铁颗粒制备及多形性胶质母细胞瘤MRI成像的初步实验研究

摘要 目的：探讨巨噬细胞膜仿生的纳米铁颗粒（Fe3O4 NCs@MM）对多形性胶质母细胞瘤MRI成像的研究。方法：制备巨噬细胞膜仿生的纳米铁颗粒Fe₃O₄ NCs@MM,利用动态光散射（Dynamic Light Scattering,DLS）和透射电子显微镜（Transmission Electron Microscope,TEM）对其水合动力学粒径、表面电势和形态进行表征。采用SDS-聚丙烯酰胺凝胶电泳（sodium dodecyl sulphate-polyacrylamide gel electrophoresis,SDS-PAGE）评价巨噬细胞膜的完整包覆;紫外可见光谱测定巨噬细胞膜仿生的纳米铁颗粒抗蛋白吸附能力。通过MRI成像系统,分析了含不同浓度的Fe元素（0.1-1.6 mM）的Fe₃O₄ NCs@MM在GSH存在或不存在时的T₁弛豫效应。采用细胞增殖-毒性实验（Cell Counting Kit-8,CCK-8）,测定巨噬细胞膜仿生纳米铁颗粒处理肿瘤细胞24 h后的细胞活性。尾静脉注射巨噬细胞膜仿生纳米铁颗粒至原位胶质母细胞瘤模型中,观察成像效果。结果：巨噬细胞膜仿生的纳米铁颗粒Fe₃O₄ NCs@MM的水合动力学粒径和表面电势分别为 286.5±7.6 nm和-20.7±3.5 mV,且在水溶液中分布均匀,具有较好的单分散性。包覆巨噬细胞膜的纳米铁颗粒具备抗蛋白吸附的能力。MRI成像显示,制备的巨噬细胞膜仿生的纳米铁颗粒Fe₃O₄ NCs@MM为GSH响应型MRI对比剂,具有较好的T₁-加权磁共振成像效果,在尾静脉注射巨噬细胞膜的纳米铁颗粒0.5 h后,肿瘤部位的信号可见增强。结论：巨噬细胞膜仿生的纳米铁颗粒Fe₃O₄ NCs@MM可实现多形性胶质母细胞瘤的MRI成像。     

烤后不同霉变程度烟叶际真菌群落组成与多样性分析

【目的】为了解烤后不同霉变程度烟叶真菌群落组成与多样性。【方法】基于IlluminaMiSeq高通量测序平台对烤后烟叶叶柄和叶片叶际样品的真菌群落组成进行了分析。【结果】霉变重烟叶叶片(BQ)、霉变重烟叶叶柄(BZ)、霉变轻烟叶叶片(JQ)、霉变轻烟叶叶柄(JZ) 4类样品真菌分布于子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、接合菌门(Zygomycota)等7个菌门、27个纲、58个目、104个科、171个属的360个真菌分类单元(OTUs)。不同霉变程度烟叶叶际真菌群落组成、分类单元的相对丰度及优势分类单元皆存在不同程度差异。在属的水平上,霉变重烟叶叶片(BQ)的优势菌属为Aspergillus (89.64%)、Myrothecium (2.54%)、Rhodotorula (2.48%)、Gibberella (1.49%);霉变重烟叶叶柄(BZ)的优势菌属为Aspergillus(96.93%)和Alternaria(1.92%);霉变轻烟叶叶片(JQ)的优势菌属为Aspergillus(40.13%)、Rhodotorula(31.81%)、Alternaria(16.75%);霉变轻烟叶叶柄(JZ)的优势菌属为Aspergillus (62.77%)、Alternaria (9.74%)、Rhodotorula (5.20%)。【结论】霉变轻烟叶叶片样品真菌群落的多样性最高,霉变轻烟叶叶柄的真菌群落丰富度最高。霉变重烟叶样品的叶片部位的真菌群落丰富度和多样性均高于叶柄。烟叶霉烂为烤房常见病害,其病原真菌种类多样,且广泛分布于烟叶和环境中。该研究结果为烤房烟叶霉烂病的防治可根据不同发病程度的不同部位的真菌群落构成特征,制定相应的防治方案提供了参考依据。     

Configuration and validation of an analytical model predicting secondary neutron radiation in proton therapy using Monte Carlo simulations and experimental measurements

PurposeThis study focuses on the configuration and validation of an analytical model predicting leakage neutron doses in proton therapy.MethodsUsing Monte Carlo (MC) calculations, a facility-specific analytical model was built to reproduce out-of-field neutron doses while separately accounting for the contribution of intra-nuclear cascade, evaporation, epithermal and thermal neutrons. This model was first trained to reproduce in-water neutron absorbed doses and in-air neutron ambient dose equivalents, H*(10), calculated using MCNPX. Its capacity in predicting out-of-field doses at any position not involved in the training phase was also checked. The model was next expanded to enable a full 3D mapping of H*(10) inside the treatment room, tested in a clinically relevant configuration and finally consolidated with experimental measurements.ResultsFollowing the literature approach, the work first proved that it is possible to build a facility-specific analytical model that efficiently reproduces in-water neutron doses and in-air H*(10) values with a maximum difference less than 25%. In addition, the analytical model succeeded in predicting out-of-field neutron doses in the lateral and vertical direction. Testing the analytical model in clinical configurations proved the need to separate the contribution of internal and external neutrons. The impact of modulation width on stray neutrons was found to be easily adjustable while beam collimation remains a challenging issue. Finally, the model performance agreed with experimental measurements with satisfactory results considering measurement and simulation uncertainties.ConclusionAnalytical models represent a promising solution that substitutes for time-consuming MC calculations when assessing doses to healthy organs.     

Pathogenic ability and saline stress tolerance of two Fusarium isolates from Odontesthes bonariensis eggs

BackgroundSeveral fungal species represent a potential risk to embryos of Odontesthes bonariensis (Cuvier and Valenciennes, 1835), a euryhaline freshwater fish that lives in the Pampean inland waters and has potential economic relevance.AimsTo identify two fungi isolated from O. bonariensis eggs exposed to saline conditions and to characterize their pathogenicity and tolerance to sodium chloride solutions.MethodsThe isolates were identified by morphological features, and a preliminar phylogenetic analysis using sequences of translation elongation factor 1-alpha (EF-1α) and calmodulin (CAM) was performed. Koch's postulates were tested to identify the causative agent of fungal infection. The influence of NaCl on the fungal growth was evaluated in in vitro assays.ResultsThe isolates LPSC 1001 and 1002 were identified as representatives of the genus Fusarium, and belonging to the Fusarium incarnatum-Fusarium equiseti species complex (FIESC) and the Fusarium solani species complex (FSSC), respectively. Histological observations on eggs exposed in vitro to both isolates in infectivity assays confirmed the ability of the fungal isolates to penetrate to egg's chorionic membrane, leading to the death of embryos. Increasing NaCl concentration in the culture medium reduced the growth of the isolates LPSC 1001 and 1002, being completely inhibited at 160 and 120 g/l NaCl respectively.ConclusionsThe isolates LPSC 1001 (FIESC) and 1002 (FSSC) were identified as fungal pathogens to O. bonariensis eggs. The use of NaCl solutions as antifungal treatment was not effective to control the infection with these strains.