《寄生虫学及检验》“教学做一体化”教学模式研究与探索

《寄生虫学及检验》是高等医学院校医学检验技术专业重要的专业基础课,其教学质量直接关系到检验医师对寄生虫病的检查水平与寄生虫病的防治效果。本文在分析目前我国本课程教学现状及存在问题的基础上,对《寄生虫学及检验》教学模式改革进行了一定的研究与探索。     

机会致病性寄生虫感染

建国以来 ,在党和政府的领导下 ,我国在寄生虫病的防治研究方面取得了显著成绩 ,过去严重流行的黑热病、疟疾、丝虫病及血吸虫病等主要寄生虫病目前已在全国范围内或大部分地区被基本消灭或控制 ,钩虫病、阿米巴痢疾等肠道寄生虫病的发病率亦已明显下降。但是 ,随着社会的发展和人类疾病谱的改变 ,人体内感染的寄生虫种类、分布及寄生虫病的流行谱也在发生着明显的变化。一些过去未被重视或少见的寄生虫感染越来越显示出对人类健康的严重危害 ,机会致病性寄生虫就是其中的一类。1　何谓机会致病性寄生虫在正常情况下 ,人体内部和体表存在有…     

黄鳝寄生虫种群生物学研究进展

黄鳝产业急速发展以及养殖面积剧增的同时,寄生虫疾病频发,给黄鳝产业造成巨大经济损失.黄鳝寄生虫种群生物学的研究对于寄生虫疾病的防治意义重大.在以往的研究基础上,本文从黄鳝寄生虫的种类、生活史和寄生关系、种群时空分布特征以及寄生虫病病症与危害等方面对黄鳝寄生虫种群生物学进行了详细的综述,并在此基础上对目前黄鳝寄生虫研究中...     

鱼类三代虫分子生物学的研究进展

三代虫是一类常见的鱼类体外寄生虫,绝大多数种类寄生于鱼类的体表和鳃,大量寄生可导致苗种甚至成鱼大批死亡,或引起其他病原感染而致继发性鱼病,造成严重的经济损失.本文从三代虫目前的分类学概况、DNA分类学和条形码技术、核糖体基因及线粒体基因的研究等方面概述了鱼类三代虫分子生物学的研究现状,为三代虫及扁形动物的分子生物学研究及其应用提供有用的资料.     

抗体芯片技术及其在寄生虫研究中的应用

随着蛋白质组学相关技术的深入发展,使病原体入侵与宿主间相互作用的研究越来越深入,蛋白质互作和蛋白质表达模式的高通量、大规模分析成为可能。通过其技术对蛋白质进行系统分析和鉴定,对疾病的发生发展具有很高的参考价值。抗体芯片分析蛋白质以其微型集成化、大规模化和高通量化的优点,广泛被应用于生物医学领域。对抗体芯片技术目前的研究进展及其在寄生虫研究方面的应用进行了阐述。寄生虫具有独特的发育过程,其不同发育阶段表达虫体蛋白及排泄分泌产物具有很大差异,将抗体芯片技术应用于寄生虫蛋白质组学研究,对特异性标识抗原筛选,探索寄生虫生长发育、定植入侵、免疫逃避和免疫抑制等具有重要意义,为寄生虫病的早期诊断及治疗,寻找新的药物靶点等奠定基础。同时,为寄生虫蛋白质组学进一步研究提供新的思路和方法。     

DNA序列分析技术及其现状

ＤＮＡ序列分析技术一直是分子生物学领域的一个重要研究课题。“人类基因组计划”的实施有力地推动了高速ＤＮＡ测序技术的发展。本文主要介绍国内外目前流行的经典的测序方法———各种改良的双脱氧链末端终止法,及近年来发展起来的一些全新的ＤＮＡ测序方法     

抑制性消减杂交技术在寄生虫学研究中的应用

抑制性消减杂交技术(SSH)是一种适用于分离两个遗传背景相关的DNA样品之间差异从而表达基因的方法。目前,该技术在寄生虫学研究中的应用不是很多,主要应用在寻找与寄生虫不同发育阶段相关的差异表达基因和与寄生虫抗药性相关的差异表达基因以及其他相关基因的研究,如与不同虫株、不同宿主、或性别差异相关的基因。本文从这几个方面综述了SSH技术在寄生虫学研究中的进展情况。了解这些信息,有助于将来更好地利用该技术研究寄生虫学,为寄生虫病的防治提供一定的理论依据。     

人工饲养条件下喜玛拉雅旱獭寄生虫病综合防治

目的制订规模化饲养喜玛拉雅旱獭寄生虫病综合防治措施,提高喜马拉雅旱獭的数量和质量及保证动物实验结果的准确性.方法 根据喜玛拉雅旱獭寄生虫检测结果,选择1%伊维菌素注射液按每千克体重0.02 ml皮下注射,连用5～7 d,制定并落实标本兼治的防疫措施和日常卫生消毒管理制度.结果给药后10 d和30 d取新鲜粪便检测,体内外寄生虫0%感染,停药90 d后未检测到寄生虫成虫和虫卵.结论通过采取药物驱虫和日常卫生管理及综合防治措施,使喜马拉雅旱獭寄生虫病控制收到良好效果.     

动物粪便中分子遗传信息的应用

动物粪便是非损伤性取样方式应用最广泛的样本,其中含有大量食物、微生物和宿主的遗传物质。本文重点介绍了结合分子生物学技术和高通量测序技术提取粪便样本的遗传信息,用于探索动物食性、肠道微生物种类及组成,检查寄生虫感染情况,筛选粪便标记物,评估种群遗传结构等应用,不仅突破了传统粪便应用研究的限制,还扩大了应用范围。通过简述粪便样本中所提取遗传信息的相关研究进展,为粪便样本在环境、野生动物和放牧动物中的应用提供参考。     

导读与评论(2016年第6期)

本期刊出稿件均为病毒学方面的内容 ,涉及分子生物学、致病机制、流行病学研究及测序新技术介绍等.其中有关致病机制密切联系临床的研究方式值得倡导.有关病毒第3代基因组测序的技术 ,对推广新技术有较好的应用价值和前景.     

Oesophagostomum dentatum: potential as a model for genomic studies of strongylid nematodes, with biotechnological prospects

There are substantial gaps in the knowledge of the molecular processes of development and reproduction in parasitic nematodes, despite the fact that understanding such processes could lead to novel ways of treating and controlling parasitic diseases, through blocking or disrupting key biological pathways. Biotechnological advances through large-scale sequencing projects, approaches for the analysis of differential gene and protein expression and functional genomics (e.g., double-stranded RNA interference) now provide opportunities to investigate the molecular basis of developmental processes in some parasitic nematodes. The porcine nodule worm, Oesophagostomum dentatum (order Strongylida), may provide a platform for testing the function of genes from this and related nematodes, given that this species can be grown and maintained in culture in vitro for periods longer than other nematodes of the same order. In this article, we review relevant biological, biochemical and molecular biological and genomic information about O. dentatum and propose that the O. dentatum - pig system provides an attractive model for exploring molecular developmental and reproductive processes in strongylid nematodes, leading toward new intervention methods and biotechnological outcomes.     

Dirofilaria hongkongensis infection presenting as recurrent shoulder mass

In 2012, a novel canine Dirofilaria species, D. hongkongensis was identified in Hong Kong that caused human diseases and subsequently reported in an Austrian traveller returning from the Indian subcontinent. Here we present a case of human infection by D. hongkongensis manifested as recurrent shoulder mass. Diagnosis was achieved by cox1 gene sequencing of the excised specimen. The case illustrated that parasitic infection represents an important differential diagnosis for musculoskeletal lesions.     

Long-read RNA sequencing of human and animal filarial parasites improves gene models and discovers operons

Filarial parasitic nematodes (Filarioidea) cause substantial disease burden to humans and animals around the world. Recently there has been a coordinated global effort to generate, annotate, and curate genomic data from nematode species of medical and veterinary importance. This has resulted in two chromosome-level assemblies (Brugia malayi and Onchocerca volvulus) and 11 additional draft genomes from Filarioidea. These reference assemblies facilitate comparative genomics to explore basic helminth biology and prioritize new drug and vaccine targets. While the continual improvement of genome contiguity and completeness advances these goals, experimental functional annotation of genes is often hindered by poor gene models. Short-read RNA sequencing data and expressed sequence tags, in cooperation with ab initio prediction algorithms, are employed for gene prediction, but these can result in missing clade-specific genes, fragmented models, imperfect mapping of gene ends, and lack of isoform resolution. Long-read RNA sequencing can overcome these drawbacks and greatly improve gene model quality. Here, we present Iso-Seq data for B. malayi and Dirofilaria immitis, etiological agents of lymphatic filariasis and canine heartworm disease, respectively. These data cover approximately half of the known coding genomes and substantially improve gene models by extending untranslated regions, cataloging novel splice junctions from novel isoforms, and correcting mispredicted junctions. Furthermore, we validated computationally predicted operons, manually curated new operons, and merged fragmented gene models. We carried out analyses of poly(A) tails in both species, leading to the identification of non-canonical poly(A) signals. Finally, we prioritized and assessed known and putative anthelmintic targets, correcting or validating gene models for molecular cloning and target-based anthelmintic screening efforts. Overall, these data significantly improve the catalog of gene models for two important parasites, and they demonstrate how long-read RNA sequencing should be prioritized for ongoing improvement of parasitic nematode genome assemblies.     

RNAi pathways in parasitic protists and worms

Tropical diseases caused by parasitic worms and protists are of major public health concern affecting millions of people worldwide. New therapeutic and diagnostic tools would be of great help in dealing with the public health and economic impact of these diseases. RNA interference (RNAi) pathways utilize small non-coding RNAs to regulate gene expression in a sequence-specific manner. In recent years, a wealth of data about the mechanisms and biological functions of RNAi pathways in distinct groups of eukaryotes has been described. Often, RNAi pathways have unique features that are restricted to groups of eukaryotes. The focus of this review will be on RNAi pathways in specific groups of parasitic eukaryotes that include Trypanosoma cruzi, Plasmodium and Schistosoma mansoni. These parasites are the causative agents of Chagas disease, Malaria, and Schistosomiasis, respectively, all of which are tropical diseases that would greatly benefit from the development of new diagnostic and therapeutic tools. In this context, we will describe specific features of RNAi pathways in each of these parasitic eukaryotic groups and discuss how they could be exploited for the treatment of tropical diseases.     

Peculiarities of aminoacyl-tRNA synthetases from trypanosomatids

Trypanosomatid parasites are responsible for various human diseases, such as sleeping sickness, animal trypanosomiasis, or cutaneous and visceral leishmaniases. The few available drugs to fight related parasitic infections are often toxic and present poor efficiency and specificity, and thus, finding new molecular targets is imperative. Aminoacyl-tRNA synthetases (aaRSs) are essential components of the translational machinery as they catalyze the specific attachment of an amino acid onto cognate tRNA(s). In trypanosomatids, one gene encodes both cytosolic- and mitochondrial-targeted aaRSs, with only three exceptions. We identify here a unique specific feature of aaRSs from trypanosomatids, which is that most of them harbor distinct insertion and/or extension sequences. Among the 26 identified aaRSs in the trypanosome Leishmania tarentolae, 14 contain an additional domain or a terminal extension, confirmed in mature mRNAs by direct cDNA nanopore sequencing. Moreover, these RNA-Seq data led us to address the question of aaRS dual localization and to determine splice-site locations and the 5′-UTR lengths for each mature aaRS-encoding mRNA. Altogether, our results provided evidence for at least one specific mechanism responsible for mitochondrial addressing of some L. tarentolae aaRSs. We propose that these newly identified features of trypanosomatid aaRSs could be developed as relevant drug targets to combat the diseases caused by these parasites.     

RNA interference in infectious tropical diseases

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.     

Tsetse flies,trypanosomes, humans and animals: what is proteomics revealing about their crosstalks?

Human and animal African trypanosomoses, or sleeping sickness and Nagana, are neglected vector-borne parasitic diseases caused by protozoa belonging to the Trypanosoma genus. Advances in proteomics offer new tools to better understand host–vector–parasite crosstalks occurring during the complex parasitic developmental cycle, and to determine the outcome of both transmission and infection. In this review, we summarize proteomics studies performed on African trypanosomes and on the interactions with their vector and mammalian hosts. We discuss the contributions and pitfalls of using diverse proteomics tools, and argue about the interest of pathogenoproteomics, both to generate advances in basic research on the best knowledge and understanding of host–vector–pathogen interactions, and to lead to the concrete development of new tools to improve diagnosis and treatment management of trypanosomoses in the near future.     

Exploring the environmental diversity of kinetoplastid flagellates in the high-throughput DNA sequencing era

The class Kinetoplastea encompasses both free-living and parasitic species from a wide range of hosts. Several representatives of this group are responsible for severe human diseases and for economic losses in agriculture and livestock. While this group encompasses over 30 genera, most of the available information has been derived from the vertebrate pathogenic genera Leishmaniaand Trypanosoma. Recent studies of the previously neglected groups of Kinetoplastea indicated that the actual diversity is much higher than previously thought. This article discusses the known segment of kinetoplastid diversity and how gene-directed Sanger sequencing and next-generation sequencing methods can help to deepen our knowledge of these interesting protists.     

新一代测序技术在遗传性耳聋基因研究及诊断中的应用

超过50%的耳聋由遗传基因缺陷所致,伴随着基因组学技术的发展,耳聋分子遗传学研究逐渐成为耳科学研究的前沿领域。新一代高通量测序技术的出现,提供了以数据为导向的新的遗传性疾病研究模式,革新了人们对遗传性疾病的认识过程,使得对遗传性疾病的研究策略也发生了重大转变。近年来新一代测序技术(Next generation sequencing,NGS)在耳聋研究中的应用,大大加快了耳聋基因发现的速度,并逐渐向临床应用方向转化。文章总结了遗传性耳聋的特点和研究现状,以及新一代测序技术在耳聋研究中的应用和前景,以及基于NGS技术的耳聋基因研究和临床耳聋基因诊断的发展方向。     

Seasonality of parasitic and saprotrophic zoosporic fungi: linking sequence data to ecological traits

Zoosporic fungi of the phylum Chytridiomycota (chytrids) regularly dominate pelagic fungal communities in freshwater and marine environments. Their lifestyles range from obligate parasites to saprophytes. Yet, linking the scarce available sequence data to specific ecological traits or their host ranges constitutes currently a major challenge. We combined 28 S rRNA gene amplicon sequencing with targeted isolation and sequencing approaches, along with cross-infection assays and analysis of chytrid infection prevalence to obtain new insights into chytrid diversity, ecology, and seasonal dynamics in a temperate lake. Parasitic phytoplankton-chytrid and saprotrophic pollen-chytrid interactions made up the majority of zoosporic fungal reads. We explicitly demonstrate the recurrent dominance of parasitic chytrids during frequent diatom blooms and saprotrophic chytrids during pollen rains. Distinct temporal dynamics of diatom-specific parasitic clades suggest mechanisms of coexistence based on niche differentiation and competitive strategies. The molecular and ecological information on chytrids generated in this study will aid further exploration of their spatial and temporal distribution patterns worldwide. To fully exploit the power of environmental sequencing for studies on chytrid ecology and evolution, we emphasize the need to intensify current isolation efforts of chytrids and integrate taxonomic and autecological data into long-term studies and experiments.Subject terms: Fungal ecology, Limnology