Host‐associated differentiation in a highly polyphagous,sexually reproducing insect herbivore

Insect herbivores may undergo genetic divergence on their host plants through host‐associated differentiation (HAD). Much of what we know about HAD involves insect species with narrow host ranges (i.e., specialists) that spend part or all their life cycle inside their hosts, and/or reproduce asexually (e.g., parthenogenetic insects), all of which are thought to facilitate HAD. However, sexually reproducing polyphagous insects can also exhibit HAD. Few sexually reproducing insects have been tested for HAD, and when they have insects from only a handful of potential host‐plant populations have been tested, making it difficult to predict how common HAD is when one considers the entire species' host range. This question is particularly relevant when considering insect pests, as host‐associated populations may differ in traits relevant to their control. Here, we tested for HAD in a cotton (Gossypium hirsutum) pest, the cotton fleahopper (CFH) (Pseudatomoscelis seriatus), a sexually reproducing, highly polyphagous hemipteran insect. A previous study detected one incidence of HAD among three of its host plants. We used Amplified fragment length polymorphism (AFLP) markers to assess HAD in CFH collected from an expanded array of 13 host‐plant species belonging to seven families. Overall, four genetically distinct populations were found. One genetically distinct genotype was exclusively associated with one of the host‐plant species while the other three were observed across more than one host‐plant species. The relatively low degree of HAD in CFH compared to the pea aphid, another hemipteran insect, stresses the likely importance of sexual recombination as a factor increasing the likelihood of HAD.     

Could cancer and infection be adverse effects of mesenchymal stromal cell therapy?

Multipotent mesenchymal stromal cells [also referred to as mesenchymal stem cells(MSCs)] are a heterogeneous subset of stromal cells. They can be isolated from bone marrow and many other types of tissue. MSCs are currently being tested for therapeutic purposes(i.e., improving hematopoietic stem cell engraftment, managing inflammatory diseases and regenerating damaged organs). Their tropism for tumors and inflamed sites and their context-dependent potential for producing trophic and immunomodulatory factors raises the question as to whether MSCs promote cancer and/or infection. Thisarticle reviews the effect of MSCs on tumor establishment, growth and metastasis and also susceptibility to infection and its progression. Data published to date shows a paradoxical effect regarding MSCs, which seems to depend on isolation and expansion, cells source and dose and the route and timing of administration. Cancer and infection may thus be adverse or therapeutic effects arising form MSC administration.     

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection

Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs.     

Vast Differences in Strain-Level Diversity in the Gut Microbiota of Two Closely Related Honey Bee Species

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Teleost intestinal immunology

Teleosts clearly have a more diffuse gut associated lymphoid system, which is morphological and functional clearly different from the mammalian GALT. All immune cells necessary for a local immune response are abundantly present in the gut mucosa of the species studied and local immune responses can be monitored after intestinal immunization. Fish do not produce IgA, but a special mucosal IgM isotype seems to be secreted and may (partly) be the recently described IgZ/IgT. Fish produce a pIgR in their mucosal tissues but it is smaller (2 ILD) than the 4–5 ILD pIgR of higher vertebrates. Whether teleost pIgR is transcytosed and cleaved off in the same way needs further investigation, especially because a secretory component (SC) is only reported in one species. Teleosts also have high numbers of IEL, most of them are CD3-?⁺/CD8-α⁺ and have cytotoxic and/or regulatory function. Possibly many of these cells are TCRγδ cells and they may be involved in the oral tolerance induction observed in fish. Innate immune cells can be observed in the teleost gut from first feeding onwards, but B cells appear much later in mucosal compartments compared to systemic sites. Conspicuous is the very early presence of putative T cells or their precursors in the fish gut, which together with the rag-1 expression of intestinal lymphoid cells may be an indication for an extra-thymic development of certain T cells. Teleosts can develop enteritis in their antigen transporting second gut segment and epithelial cells, IEL and eosinophils/basophils seem to play a crucial role in this intestinal inflammation model. Teleost intestine can be exploited for oral vaccination strategies and probiotic immune stimulation. A variety of encapsulation methods, to protect vaccines against degradation in the foregut, are reported with promising results but in most cases they appear not to be cost effective yet. Microbiota in fish are clearly different from terrestrial animals. In the past decade a fast increasing number of papers is dedicated to the oral administration of a variety of probiotics that can have a strong health beneficial effect, but much more attention has to be paid to the immune mechanisms behind these effects. The recent development of gnotobiotic fish models may be very helpful to study the immune effects of microbiota and probiotics in teleosts.     

Prediction of recurrence using exfoliative cytology and melanoma‐associated antigen‐A mRNA analysis following wide excision of oral squamous cell carcinoma: short report

N. Mollaoglu, P. Metzler, J. Zenk, E. Nkenke, F. W. Neukam and J. Ries
Prediction of recurrence using exfoliative cytology and melanoma‐associated antigen‐A mRNA analysis following wide excision of oral squamous cell carcinoma: short report Background: Oral squamous cell carcinoma (OSCC) is the sixth most common cancer. The local recurrence of OSSC might result from the existence of occult cancer cells around tumour margins. Exfoliative cytology has lately gained great importance as a method for obtaining RNA samples from suspicious oral mucosal lesions in order to carry out molecular diagnosis. In addition, melanoma associated‐A antigens (MAGE‐A) are expressed in various tumours and their detection is a highly accurate sign that cancer cells are present. Objective: The prediction of a recurrence using MAGE‐A mRNA expression analysis to follow‐up OSCC cases using a newly established molecular diagnostic technique applied to cytological materials. Methods: RNA was extracted from three recurrent OSCC cases and from 20 healthy volunteers as a control group using a cytobrush. The expression of MAGE‐A3, A4, A6, A10 and A12 was investigated in these specimens using quantitative real‐time (RT‐PCR). Results: There was no expression of MAGE‐A in the specimens of normal oral mucosa. However, the expression analysis of five different MAGE‐A genes indicated a high potential for malignant change in biopsy‐proven recurrent OSCC cases. Except for MAGE‐A10, the rest of the genes were expressed in different ratios by the three recurrent cases, which had been determined on histopathology to be OSCC or carcinoma in situ. Conclusion: It is suggested that analysis of MAGE‐A expression may be used as a risk prediction method in the diagnosis of recurrence after wide excision of OSCC to enhance the accuracy of exfoliative cytology, which has limitations due to false negative and false positive results.     

突触小体相关蛋白SNAP25的原核表达、纯化及鉴定

目的:克隆突触小体相关蛋白(SNAP25)基因,原核表达、纯化并鉴定SNAP25蛋白。方法:PCR扩增SNAP25基因,克隆至表达质粒pTIG-Trx,转化大肠杆菌BL21(DE3)感受态细胞,IPTG诱导表达,Ni2+-NTA亲和层析纯化目的蛋白,SDS-PAGE及Western印迹分析肉毒神经毒素BoNT/A轻链对该蛋白的裂解情况。结果:构建了pTIG-SNAP25表达质粒,经IPTG诱导表达,目的蛋白占全菌蛋白的26.2%,表达形式为可溶性表达,表达量达115.4mg/L,纯化后蛋白纯度达95%以上;经SDS-PAGE及Western印迹分析,SNAP25蛋白可被BoNT/A轻链特异降解。结论:克隆了SNAP25基因,在原核系统中表达、纯化并鉴定了重组SNAP25蛋白。     

淋病奈瑟菌感染实验室检测技术的进展

细菌培养是诊断淋病奈瑟菌(NG)感染的"金标准",也是目前诊断淋病最可靠的方法.但淋病奈瑟菌在人体外抵抗力极弱,不易培养;仅做细菌形态学检查,诊断意义有限.随着淋病奈瑟菌耐药性不断增强,多重耐药菌出现并广泛传播.高敏感性、高特异性、操作简便的分子生物学检验技术,如单管多重聚合酶链反应(PCR)技术等,已开始用于淋病奈瑟...     

利用恒河婴猴模型对肠道病毒71型传播感染特征的生物学分析

本文在前期工作基础上,进一步对肠道病毒71型(EV71)从恒河婴猴的感染个体向其他未感染个体传播的可能性及相关生物学特性做了初步分析.通过喷雾形式经呼吸道感染1~2月龄恒河婴猴(A组);在观察临床症状同时,于感染后第7天,取该组动物粪便处理后,将上清液以喷雾形式经呼吸道感染新的婴猴个体(B组),随后对该次代感染个体进行...     

Impacts of climate warming on hybrid zone movement: Geographically diffuse and biologically porous “species borders”

Abstract The ecology and evolutionary biology of insect–plant associations has realized extensive attention, especially during the past 60 years. The classifications (categorical designations) of continuous variation in biodiversity, ranging from global patterns (e.g., latitudinal gradients in species richness/diversity and degree of herbivore feeding specialization) to localized insect–plant associations that span the biospectrum from polyphenisms, polymorphisms, biotypes, demes, host races, to cryptic species, remain academically contentious. Semantic and biosystematic (taxonomical) disagreements sometimes detract from more important ecological and evolutionary processes that drive diversification, the dynamics of gene flow and local extinctions. This review addresses several aspects of insect specialization, host‐associated divergence and ecological (including “hybrid”) speciation, with special reference to the climate warming impacts on species borders of hybridizing swallowtail butterflies (Papilionidae). Interspecific hybrid introgression may result in collapse of multi‐species communities or increase species numbers via homoploid hybrid speciation. We may see diverging, merging, or emerging genotypes across hybrid zones, all part of the ongoing processes of evolution. Molecular analyses of genetic mosaics and genomic dynamics with “divergence hitchhiking”, combined with ecological, ethological and physiological studies of “species porosity”, have already begun to unveil some answers for some important ecological/evolutionary questions. (i) How rapidly can host‐associated divergence lead to new species (and why doesn't it always do so, e.g., resulting in “incomplete” speciation)? (ii) How might “speciation genes” function, and how/where would we find them? (iii) Can oscillations from specialists to generalists and back to specialists help explain global diversity in herbivorous insects? (iv) How could recombinant interspecific hybridization lead to divergence and speciation? From ancient phytochemically defined angiosperm affiliations to recent and very local geographical mosaics, the Papilionidae (swallowtail butterflies) have provided a model for enhanced understanding of ecological patterns and evolutionary processes, including host‐associated genetic divergence, genomic mosaics, genetic hitchhiking and sex‐linked speciation genes. Apparent homoploid hybrid speciation in Papilio appears to have been catalyzed by climate warming‐induced interspecific introgression of some, but not all, species diagnostic traits, reflecting strong divergent selection (discordant), especially on the Z (= X) chromosome. Reproductive isolation of these novel recombinant hybrid genotypes appears to be accomplished via a delayed post‐diapause emergence or temporal isolation, and is perhaps aided by the thermal landscape. Changing thermal landscapes appear to have created (and may destroy) novel recombinant hybrid genotypes and hybrid species.