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  • 1.

    【2hr】Soil bacterial communities of Sahara and Gibson deserts: Physiological and taxonomical characteristics

    包量

    机译 撒哈拉沙漠和吉布森沙漠的土壤细菌群落：生理和分类学特征
    摘要：The purpose of this research was to investigate the structure of soil bacteria communities present in the Gibson (Australia) and the Sahara (Egypt) deserts, as well as to estimate strain survivability under different environmental factors. It should be noticed that the screening of bacterial resistance to wide spectra of principally different stress conditions was performed for the first time. Experiments were conducted with culturable bacterial communities. Strains were identified using 16S rRNA sequencing, and stress-tolerance was estimated by growing strains in various nutrient media. In order to characterize the community the epifluorescent microscopy and multisubstrate testing were also performed. High bacterial abundance in the desert soils was detected, and there was seen a significant proportion of culturable cells. The close numbers of psychotropic and mesophilic bacteria in arid ecosystems were revealed. The representatives of the Actinobacteria phylum were dominant in the microbial communities, and Firmicutes, Proteobacteria, and Bacteroidetes phyla representatives were also identified. Tolerance of the axenic bacterial cultures, isolated from arid desert ecotopes, to temperature, pH, salts (KCl, NaCl, MgSO4, NaHCO3), strong oxidizers (Mg(ClO4)2), and antibiotics (ampicillin, cephalexin, chloramphenicol, tetracycline, doxycycline, kanamycin, rifampicin) was studied. The bacterial isolates were characterized by polyextremotolerance and by the ability to maintain metabolic activity in vitro while influenced by a wide range of physicochemical and biotic factors.
  • 2.

    【2hr】Biofilm formation and adhesion to bovine udder epithelium of potentially probiotic lactic acid bacteria

    包量

    机译 生物膜的形成和潜在益生菌乳酸菌对牛乳房上皮的粘附
    摘要：Mastitis is one of the most important diseases threatening modern dairy herds. The idea of fighting the disease through colonising the udder with lactic acid bacteria (LAB), thereby building a beneficial biofilm, is the base for a probiotic approach towards mastitis control. The purpose of this study was to screen 13 LAB strains (eleven wild strains, two ATCC strains) inhibitory to the growth of mastitis-causing pathogens for their in vitro ability to form a biofilm and to adhere to bovine glandular mammary epithelium in order to assess their probiotic potential. Furthermore, we aimed to gain knowledge about the chemical nature of the adhesins involved by subjecting the bacteria to various chemical and enzymatical pre-treatments. The biofilms were grown on hydrophilic glass and on hydrophobic polypropylene in de Man, Rogosa and Sharpe (MRS) broth and afterwards quantified with a crystal violet assay. Biofilm formation was observed in all strains. However, the extent strongly depended on the strain, surface charge and medium. The adhesion assay also revealed a strong strain dependency, but this trait was also present in all of the investigated LAB isolates. Depending on the strain, chemical or enzymatical pre-treatment revealed carbohydrate molecules as well as proteins and lipids to be crucial for the adhesion of LAB to epithelial cells. The seven strains showing the strongest biofilm formation and/or adhesion represent promising candidates for further investigation in order to develop a probiotic remedy for the treatment of mastitis. Still, their safety for consumers and patients as well as their capability to colonise the udder remain to be investigated in in vivo studies.
  • 3.

    【2hr】Analysis of gastrointestinal virus infection in immunocompromised hosts by multiplex virus PCR assay

    包量

    机译 多重病毒PCR检测分析免疫受损宿主中的胃肠道病毒感染
    摘要：Regarding viral infection of intestinal mucosa, there have been only a few studies on limited diseases, targeting a few herpes family viruses. In this study, we analyzed 12 kinds of DNA viruses including 8 species of herpes family viruses in the gastrointestinal mucosa of patients with hematologic malignancies, inflammatory bowel diseases, collagen diseases, or other miscellaneous forms of gastroenteritis using the multiplex virus PCR assay, which we recently developed. The virus PCR assay yielded positive results in 63 of 102 patients; Epstein-Barr virus (EBV) was the most frequently detected, followed by cytomegalovirus (CMV), human herpes virus 6 (HHV-6), HHV-7, parvovirus B19, and herpes simplex virus type 1. The frequencies of viral detection in the 4 diseases were similar involving these 6 viruses. Regarding CMV colitis, the multiplex virus PCR assay was superior to the immunohistopathologic method in detecting CMV. All viruses were more efficiently detected in the mucosa than in the blood in individual patients. These results suggest that CMV, EBV, and HHV-6 were commonly detected in the gastrointestinal mucosa of patients with these 4 diseases, and our multiplex virus PCR assay was useful for the early diagnosis of gastrointestinal virus infection, especially CMV colitis.
  • 4.

    【2hr】Metatranscriptomics profile of the gill microbial community during Bathymodiolus azoricus aquarium acclimatization at atmospheric pressure

    包量

    机译 大气重氮梭菌水族馆适应过程中ill微生物群落的转录组学谱
    摘要：BackgroundThe deep-sea mussels Bathymodiolus azoricus (Bivalvia: Mytilidae) are the dominant macrofauna subsisting at the hydrothermal vents site Menez Gwen in the Mid-Atlantic Ridge (MAR). Their adaptive success in such challenging environments is largely due to their gill symbiotic association with chemosynthetic bacteria. We examined the response of vent mussels as they adapt to sea-level environmental conditions, through an assessment of the relative abundance of host-symbiont related RNA transcripts to better understand how the gill microbiome may drive host-symbiont interactions in vent mussels during hypothetical venting inactivity.
  • 5.

    【2hr】Low temperatures can promote cyanobacterial bloom formation by providing refuge from microbial antagonists

    包量

    机译 低温可通过提供微生物拮抗剂的庇护而促进蓝藻水华的形成
    摘要：Freshwater cyanobacteria are prone to a wide range of highly potent microbial antagonists. Most of these exploit their prey in a frequency-dependent manner and are therefore particularly well suited to prevent any accumulation of cyanobacteria. Mass developments of cyanobacteria, the so-called blooms, should therefore be rare events, which is in striking contrast to what we actually see in nature. Laboratory experiments of the present study showed that the temperature range 5.8–10 °C forms a thermal refuge, inside which the cyanobacterium Planktothrix can grow without being exploited by two otherwise highly potent microbial antagonists. In nature, access of Planktothrix to this refuge was associated with positive net growth and a high probability of bloom formation, confirming that refuge temperatures indeed allow Planktothrix to grow with a minimum of biomass loss caused by microbial antagonists. Contact to higher temperatures, in contrast, was associated with decreases in net growth rate and in probability of bloom formation, with population collapses and with the occurrence of parasite infection. This is in agreement with the finding of laboratory experiments that above 10 °C exploitation of Planktothrix by multiple microbes increases in a temperature-dependent manner. Taken together, above findings suggest that temperature modulates the microbial control of natural Planktothrix populations. Low temperatures form a thermal refuge that may promote Planktothrix bloom formation by shielding the cyanobacterium from otherwise highly potent microbial antagonists.
  • 6.

    【2hr】A study on the potential of ants to act as vectors of foodborne pathogens

    包量

    机译 蚂蚁作为食源性病原体媒介的潜力研究
    摘要：Ants (Technomyrmex difficilis and Solenopsis geminata) are insects often found in domestic kitchens of Mauritius. Unfortunately, they harbour disease-causing organisms and can potentially transfer these pathogens to food. This study was carried out to (i) investigate the knowledge, perception and behaviors of consumers in relation to the problem of ant infestation of domestic kitchens; (ii) identify the pathogenic microorganisms carried by ants; and (iii) determine the potential for ants to transfer these pathogenic microorganisms to food. A survey based on a stratified sampling design was carried out with 100 consumers using a questionnaire. To identify the pathogenic microorganism(s) harbored by ants, bait traps were set up using sterile sugar as a non-toxic attractant. Captured ants were then subjected to microbiological analyses. Most respondents (72%) agreed that ants constitute a hygienic issue but they did not perceive ants as a serious threat to human health. However microbiological analyses of ants (n = 50) confirmed the presence of various pathogenic microorganisms as well as fecal contaminants. Ants were found to harbor yeasts and molds systematically (100%), coliforms frequently (52%), Bacillus spp. and Escherichia coli occasionally (26% and 18% respectively) and Salmonella and Listeria monocytogenes sporadically (8 and 6 % respectively). Ants were also found to transfer E. coli to food surfaces at a moderately high frequency of 70%. This study demonstrated that the majority of consumers acknowledged the problem of ant infestation as a sanitation-related problem rather than a food safety issue. Since ants have the ability to harbor and subsequently transfer pathogenic or toxigenic microorganisms, ants may act as disease vectors and contaminate food, water and food- contact surfaces of kitchens resulting in foodborne illnesses.
  • 7.

    【2hr】Microbiological safety of flours used in follow up for infant formulas produced in Ouagadougou, Burkina Faso

    包量

    机译 在布基纳法索瓦加杜古生产的婴儿配方奶粉的后续检查中使用的面粉的微生物学安全性
    摘要：The prevalence of diarrheal diseases in children aged from 6 to 24 months in Burkina Faso is 38%. These diarrheas may be due to the consumption of contaminated weaning food. Therefore, the microbiological quality of follow up infant flours used as supplement foods is a key-point to reduce children diseases. In this study, the microbiological safety of locally-produced infant flours was investigated. One hundred and ninety-nine (199) samples were collected mainly in retails outlets and in Recovery and Nutrition Education Centers. According to the Burkina Faso regulations, microbiological analyses were carried out for Total Aerobic Mesophilic Flora (TAMF), thermotolerant coliforms, Salmonella spp. and yeasts/molds. The bacterial and fungal isolates were identified using phenotypic and genotypic methods and the study of the production of mycotoxins was carried out from the fungal isolates. In collected samples, the TAMF count ranged from 0 to 1.8 × 106 CFU/g with a total average of 6.3 × 104 CFU/g. About 2% of the samples had a microbial load exceeding the standards (105 CFU/g). No Salmonella spp. was isolated in the final infant flours. However, the presence of Enterobacteriaceae (Klebsiella spp. Enterobacter spp. and Cronobacter spp.) was detected and molecular characterization revealed also the presence of fungal species of the genus Aspergillus spp., Penicillium spp. and Fusarium spp. Some of these species were found to produce aflatoxins, ochratoxin A and fumonisins, which are potential carcinogenic toxins. These results demonstrated the need for a preventive approach based on the application of Hazard Analysis Critical Control Point in the food industry to ensure food safety of infant flours in Burkina Faso.
  • 8.

    【2hr】Industrial production, application, microbial biosynthesis and degradation of furanic compound, hydroxymethylfurfural (HMF)

    包量

    机译 呋喃化合物，羟甲基糠醛（HMF）的工业生产，应用，微生物生物合成和降解
    摘要：Biorefinery is increasingly embraced as an environmentally friendly approach that has the potential to shift current petroleum-based chemical and material manufacture to renewable sources. Furanic compounds, particularly hydroxymethylfurfurals (HMFs) are platform chemicals, from which a variety of value-added chemicals can be derived. Their biomanufacture and biodegradation therefore will have a large impact. Here, we first review the potential industrial production of 4-HMF and 5-HMF, then we summarize the known microbial biosynthesis and biodegradation pathways of furanic compounds with emphasis on the enzymes in each pathway. We especially focus on the structure, function and catalytic mechanism of MfnB (4-(hydroxymethyl)-2-furancarboxyaldehyde-phosphate synthase) and hmfH (HMF oxidase), which catalyze the formation of phosphorylated 4-HMF and the oxidation of 5-HMF to furandicarboxylic acid (2,5-FDCA), respectively. Understanding the structure-function relationship of these enzymes will provide important insights in enzyme engineering, which eventually will find industry applications in mass-production of biobased polymers and other bulk chemicals in future.
  • 9.

    【2hr】Extracellular polymeric substances, a key element in understanding biofilm phenotype

    包量

    机译 细胞外聚合物，了解生物膜表型的关键因素
    摘要：One of the key elements in the establishment and maintenance of the biofilm structure and properties is the extracellular matrix. The extracellular matrix is composed of water and extracellular polymeric substances (EPS): primarily polysaccharides, proteins and DNA. Characterization of the matrix requires component identification, as well as determination of the relative concentration of EPS constituents, including their physicochemical properties and descriptions of their interactions. Several types of experimental approaches with varying degrees of destructiveness can be utilized for this characterization. The analysis of biofilm by infrared spectroscopy gives information about the chemical content of the matrix and the proportions of different EPS. The sensitivity of a biofilm to hydrolytic enzymes targeting different EPS gives insight into the composition of the matrix and the involvement of matrix components in the integrity of the structure. Using both chemical and physical treatments, extraction and purification of EPS from the biofilm also provides a means of determining matrix composition. Purified and/or artificial EPS can be used to obtain artificial matrices and to study their properties. Using examples from the literature, this review will illustrate selected technologies useful in the study of EPS that provide a better understanding of the structure-function relationships in extracellular matrix, and thus the structure-function relationships of the biofilm phenotype.
  • 10.

    【2hr】Autoimmune liver disease and the enteric microbiome

    包量

    机译 自身免疫性肝病和肠道微生物组
    摘要：The human enteric microbiome is highly complex and has more than 150 times more genes within it than its host. The host and the microbiome have a commensurate relationship that can evolve over time. The typically symbiotic relationship between the two can become pathogenic. The microbiome composition in adults reflects their history of exposure to bacteria and environmental factors during early life, their genetic background, age, interactions with the immune system, geographical location, and, most especially, their diet. Similarly, these factors are thought to contribute to the development of autoimmune disease. It is possible that alterations in the intestinal microbiome could lead to liver disease. There is emerging data for the contribution of the microbiome in development of primary sclerosing cholangitis, primary biliary cholangitis, and autoimmune hepatitis; liver disorders associated with aberrant immune function in genetically susceptible individuals.
  • 11.

    【2hr】Intracellular proteins moonlighting as bacterial adhesion factors

    包量

    机译 细胞内蛋白质作为细菌粘附因子而受到关注
    摘要：Pathogenic and commensal, or probiotic, bacteria employ adhesins on the cell surface to attach to and interact with the host. Dozens of the adhesins that play key roles in binding to host cells or extracellular matrix were originally identified as intracellular chaperones or enzymes in glycolysis or other central metabolic pathways. Proteins that have two very different functions, often in two different subcellular locations, are referred to as moonlighting proteins. The intracellular/surface moonlighting proteins do not contain signal sequences for secretion or known sequence motifs for binding to the cell surface, so in most cases is not known how these proteins are secreted or how they become attached to the cell surface. A secretion system in which a large portion of the pool of each protein remains inside the cell while some of the pool of the protein is partitioned to the cell surface has not been identified. This may involve a novel version of a known secretion system or it may involve a novel secretion system. Understanding the processes by which intracellular/cell surface moonlighting proteins are targeted to the cell surface could provide novel protein targets for the development of small molecules that block secretion and/or association with the cell surface and could serve as lead compounds for the development of novel antibacterial therapeutics.
  • 12.

    【2hr】The three-legged stool of understanding metabolism: integrating metabolomics with biochemical genetics and computational modeling

    包量

    机译 理解代谢的三足凳：将代谢组学与生化遗传学和计算模型相结合
    摘要：Traditional biochemical research has resulted in a good understanding of many aspects of metabolism. However, this reductionist approach is time consuming and requires substantial resources, thus raising the question whether modern metabolomics and genomics should take over and replace the targeted experiments of old. We proffer that such a replacement is neither feasible not desirable and propose instead the tight integration of modern, system-wide omics with traditional experimental bench science and dedicated computational approaches. This integration is an important prerequisite toward the optimal acquisition of knowledge regarding metabolism and physiology in health and disease. The commentary describes advantages and drawbacks of current approaches to assessing metabolism and highlights the challenges to be overcome as we strive to achieve a deeper level of metabolic understanding in the future.
  • 13.

    【2hr】Modulation of antimicrobial efflux pumps of the major facilitator superfamily in Staphylococcus aureus

    包量

    机译 金黄色葡萄球菌主要促进者超家族的抗菌外排泵的调节
    摘要：Variants of the microorganism Staphylococcus aureus which are resistant to antimicrobial agents exist as causative agents of serious infectious disease and constitute a considerable public health concern. One of the main antimicrobial resistance mechanisms harbored by S. aureus pathogens is exemplified by integral membrane transport systems that actively remove antimicrobial agents from bacteria where the cytoplasmic drug targets reside, thus allowing the bacteria to survive and grow. An important class of solute transporter proteins, called the major facilitator superfamily, includes related and homologous passive and secondary active transport systems, many of which are antimicrobial efflux pumps. Transporters of the major facilitator superfamily, which confer antimicrobial efflux and bacterial resistance in S. aureus, are good targets for development of resistance-modifying agents, such as efflux pump inhibition. Such modulatory action upon these antimicrobial efflux systems of the major facilitator superfamily in S. aureus may circumvent resistance and restore the clinical efficacy of therapy towards S. aureus infection.
  • 14.

    【2hr】Oral microbiome and health

    包量

    机译 口腔微生物组与健康
    摘要：The oral microbiome is diverse in its composition due to continuous contact of oral cavity with the external environment. Temperatures, diet, pH, feeding habits are important factors that contribute in the establishment of oral microbiome. Both culture dependent and culture independent approaches have been employed in the analysis of oral microbiome. Gene-based methods like PCR amplification techniques, random amplicon cloning, PCR-RELP, T-RELP, DGGE and DNA microarray analysis have been applied to increase oral microbiome related knowledge. Studies revealed that microbes from the phyla Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, Fusobacteria, Neisseria, TM7 predominately inhabits the oral cavity. Culture-independent molecular techniques revealed the presence of genera Megasphaera, Parvimonas and Desulfobulbus in periodontal disease. Bacteria, fungi and protozoa colonize themselves on various surfaces in oral cavity. Microbial biofilms are formed on the buccal mucosa, dorsum of the tongue, tooth surfaces and gingival sulcus. Various studies demonstrate relationship between unbalanced microflora and development of diseases like tooth caries, periodontal diseases, type 2 diabetes, circulatory system related diseases etc. Transcriptome-based remodelling of microbial metabolism in health and disease associated states has been well reported. Human diets and habitat can trigger virus activation and influence phage members of oral microbiome. As it is said, “Mouth, is the gateway to the total body wellness, thus oral microbiome influences overall health of an individual”.
  • 15.

    【2hr】Adhesion properties of toxigenic corynebacteria

    包量

    机译 产毒棒杆菌的粘附特性
    • 作者：Lisa Ott
    • 刊名：AIMS Microbiology
    • 2018年第1期
    摘要：Corynebacterium diphtheriae, Corynebacterium pseudotuberculosis and Corynebacterium ulcerans share one distinctive feature: they are all putative carriers of the diphtheria toxin (DT), encoded by a β-corynephage integrated into the genome. Due to its medical relevance, C. diphtheriae may be the most highly investigated species of the genus Corynebacterium. Nevertheless, systemic infections caused by C. ulcerans are increasingly being reported indicating that this species is an emerging pathogen today. C. diphtheriae, C. pseudotuberculosis and C. ulcerans are able to colonize different types of epithelial cells in a strain-specific manner, independent of the presence of the tox gene. However, the molecular mechanisms contributing to host colonization are barely understood. This review gives a comprehensive update of recent data concerning the adhesion properties of toxigenic corynebacteria, demonstrating that adhesion is a multi-factorial process.
  • 16.

    【2hr】Bacterial autoaggregation

    包量

    机译 细菌自动聚集
    摘要：Many bacteria, both environmental and pathogenic, exhibit the property of autoaggregation. In autoaggregation (sometimes also called autoagglutination or flocculation), bacteria of the same type form multicellular clumps that eventually settle at the bottom of culture tubes. Autoaggregation is generally mediated by self-recognising surface structures, such as proteins and exopolysaccharides, which we term collectively as autoagglutinins. Although a widespread phenomenon, in most cases the function of autoaggregation is poorly understood, though there is evidence to show that aggregating bacteria are protected from environmental stresses or host responses. Autoaggregation is also often among the first steps in forming biofilms. Here, we review the current knowledge on autoaggregation, the role of autoaggregation in biofilm formation and pathogenesis, and molecular mechanisms leading to aggregation using specific examples.
  • 17.

    【2hr】Hurdle factors minimizing growth of Listeria monocytogenes while counteracting in situ antilisterial effects of a novel nisin A-producing Lactococcus lactis subsp. cremoris costarter in thermized cheese milks

    包量

    机译 阻碍最小化单核细胞增生李斯特菌生长的因素，同时抵消了产生乳链菌肽A的新型乳酸乳球菌亚种的原位抗利斯特作用。芝士奶中的cremoris costarter
    摘要：The capacity of growth, survival, and adaptive responses of an artificial contamination of a three-strain L. monocytogenes cocktail in factory-scale thermized (65 °C, 30 s) Graviera cheese milk (TGCM) was evaluated. Bulk TGCM samples for inoculation were sequentially taken from the cheese making vat before process initiation (CN-LM) and after addition of a commercial starter culture (CSC), the CSC plus the nisin A-producing (NisA+) costarter strain Lactococcus lactis subsp. cremoris M78 (CSC + M78), and all ingredients with the rennet last (CSC + M78-RT). Additional treatments included Listeria-inoculated TGCM samples coinoculated with the NisA+ costarter strain M78 in the absence of the CSC or with the CSC in previously sterilized TGCM to inactivate the background microbiota (CSC-SM). All cultures were incubated at 37 to 42 °C for 6 h, followed by additional 66 h at 22 °C, and 48 h at 12 °C after addition of 2% edible salt. L. monocytogenes failed to grow and declined in all CSC-inoculated treatments after 24 h. In contrast, the pathogen increased by 3.34 and 1.46 log units in the CN-LM and the CSC-SM treatments, respectively, indicating that the background microbiota or the CSC alone failed to suppress it, but they did so synergistically. Supplementation of the CSC with the NisA+ strain M78 did not deliver additional antilisterial effects, because the CSC Streptococcus thermophilus reduced the growth prevalence rates and counteracted the in situ NisA+ activity of the costarter. In the absence of the CSC, however, strain M78 predominated and caused the strongest in situ nisin-A mediated effects, which resulted in the highest listerial inactivation rates after 24 to 72 h at 22 °C. In all TGCM treatments, however, L. monocytogenes displayed a “tailing” survival (1.63 to 1.96 log CFU/mL), confirming that this pathogen is exceptionally tolerant to cheese-related stresses, and thus, can't be easily eliminated.
  • 18.

    【2hr】Antilisterial activity of Cymbopogon citratus on crabsticks

    包量

    机译 柠檬角柏的抗李斯特菌活性
    摘要：Listeria monocytogenes is a gram positive, psychrotrophic, facultative anaerobic bacterium and it is the etiological agent of listeriosis, a severe foodborne disease of major public health concern. There is a rising concern about the cross-contamination of surimi-based products with L. monocytogenes during handling and storage. Lemon grass (Cymbopogon citratus) is known to exhibit strong antimicrobial activity against bacteria due to the presence of citral. The objectives of this research were: (i) to develop a water-based extraction procedure for the antimicrobial component(s) in lemon grass and (ii) to evaluate the antimicrobial effect of a concentrated water-based extract and commercial essential oil (EO) of lemon grass against L. innocua (ATCC 33090), a surrogate strain of L. monocytogenes, in vitro and on crabsticks. Briefly, antilisterial activity of concentrated extract and commercial EO of lemon grass was tested using the agar well diffusion technique. Crabsticks were subsequently inoculated with L. innocua to a final density of ca. 4 log cfu/g and then coated with 500 μl of either concentrated extract or 0.5% commercial EO and stored at 4 °C for up to 15 days. Samples were then subjected to microbiological analysis every 5 days to enumerate counts of Listeria. Following the agar well diffusion assay, inhibition zones with mean diameters of 18.3 and 21.0 mm were obtained with the concentrated extract and commercial EO respectively. The population of L. innocua in WBE-coated (4.2 log cfu/g) and 0.5% EO-coated (2.7 log cfu/g) samples were significantly lower (P < 0.05) after 15 days than their untreated control counterpart (5.2 log cfu/g). Lemon grass extract and essential oil have the potential to control growth of L. monocytogenes in seafood surimi products with minimal adverse effect on the organoleptic characteristics of the product and thus can possibly be used as a natural food preservative.
  • 19.

    【2hr】Interactions between ectomycorrhizal fungi and chestnut blight (Cryphonectria parasitica) on American chestnut (Castanea dentata) used in coal mine restoration

    包量

    机译 外生菌根真菌与板栗枯萎病（Cryphonectria parasitica）与用于煤矿恢复的美国板栗（Castanea dentata）之间的相互作用
    摘要：Plant and fungal interactions drive successional trajectories within reforestation offering both mutualisms (ectomycorrhizal fungi [ECM]) and fungal pathogens. Appalachian forest and mine reclamation projects re-introducing American chestnut and chestnut hybrids will inevitably document the return of chestnut blight, resulting in cankers causing branch dieback and loss of photosynthetic tissue. Similar to herbivory, the loss of photosynthetic tissue may reduce ECM root colonization and cause changes in fungal species composition. To test this, 75 six-year-old established chestnut trees were selected to represent the following: (1) Healthy trees free of chestnut blight; (2) trees with cankers and 50% branch dieback; (3) trees that died prior to the fifth growing season. Each tree had a chestnut seed planted 24 cm from the base. ECM colonization of both the established parent trees (n = 50) and five-month-old seedlings (n = 64) were quantified and genera determined by fungal DNA sequencing of the internal transcribed (ITS) region. Healthier seven-year-old chestnuts trees had significantly more ECM roots than those trees infected with chestnut blight cankers. However, disease die-back on chestnut did not have an influence on community composition among the parent trees or the neighboring five month seedlings. Results also demonstrated that five-month-old seedlings neighboring healthy parent trees had greater ECM on roots (P = 0.002), were larger in size (P = 0.04), and had greater survival (P = 0.01). ECM genera such as Cortinarius, Russula and Scleroderma provided tree to seedling inoculation. ECM colonization by Cortinarius spp. resulted in larger chestnut plants and increased nitrogen foliar concentrations on the five month seedlings. It can be hypothesized that blight will aid in diversifying forest stand composition and these early ECM networks will help facilitate the survival of other native hardwoods that recruit into these sites over time.
  • 20.

    【2hr】Analysis of immune-related genes during Nora virus infection of Drosophila melanogaster using next generation sequencing

    包量

    机译 下一代测序技术分析果蝇黑斑病菌在诺拉病毒感染过程中的免疫相关基因
    摘要：Drosophila melanogaster depends upon the innate immune system to regulate and combat viral infection. This is a complex, yet widely conserved process that involves a number of immune pathways and gene interactions. In addition, expression of genes involved in immunity are differentially regulated as the organism ages. This is particularly true for viruses that demonstrate chronic infection, as is seen with Nora virus. Nora virus is a persistent non-pathogenic virus that replicates in a horizontal manner in D. melanogaster. The genes involved in the regulation of the immune response to Nora virus infection are largely unknown. In addition, the temporal response of immune response genes as a result of infection has not been examined. In this study, D. melanogaster either infected with Nora virus or left uninfected were aged for 2, 10, 20 and 30 days. The RNA from these samples was analyzed by next generation sequencing (NGS) and the resulting immune-related genes evaluated by utilizing both the PANTHER and DAVID databases, as well as comparison to lists of immune related genes and FlyBase. The data demonstrate that Nora virus infected D. melanogaster exhibit an increase in immune related gene expression over time. In addition, at day 30, the data demonstrate that a persistent immune response may occur leading to an upregulation of specific immune response genes. These results demonstrate the utility of NGS in determining the potential immune system genes involved in Nora virus replication, chronic infection and involvement of antiviral pathways.
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