scholarly journals Pathogenicity and Infection Cycle of Vibrio owensii in Larviculture of the Ornate Spiny Lobster (Panulirus ornatus)

2012 ◽  
Vol 78 (8) ◽  
pp. 2841-2849 ◽  
Author(s):  
Evan F. Goulden ◽  
Michael R. Hall ◽  
David G. Bourne ◽  
Lily L. Pereg ◽  
Lone Høj
Keyword(s):  
Fluorescent Protein ◽  
Histopathological Examination ◽  
Single Cells ◽  
Larval Mortality ◽  
Spiny Lobster ◽  
Systemic Infection ◽  
Mortality Rates ◽  
Infection Process ◽  
Content Type ◽  
Live Feed

ABSTRACTThe type strain ofVibrio owensii(DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus).V. owensiiDY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organismArtemia(brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeledV. owensiiDY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection.V. owensiiDY05 is a marine enteropathogen highly virulent toP. ornatusphyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.

scholarly journals A Distinct, Non-Virion Plant Virus Movement Protein Encoded by a Crinivirus Essential for Systemic Infection

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Wenjie Qiao ◽  
Vicente Medina ◽  
Yen-Wen Kuo ◽  
Bryce W. Falk
Keyword(s):  
Fluorescent Protein ◽  
Movement Protein ◽  
Biological Significance ◽  
Systemic Infection ◽  
Plant Viruses ◽  
In Planta ◽  
Virion Protein ◽  
Content Type ◽  
Lettuce Infectious Yellows Virus ◽  
Systemic Infections

ABSTRACTPlant-infecting viruses utilize various strategies involving multiple viral and host factors to achieve successful systemic infections of their compatible hosts.Lettuce infectious yellows virus(LIYV), genusCrinivirus, familyClosteroviridae, has long, filamentous flexuous virions and causes phloem-limited infections in its plant hosts. The LIYV-encoded P26 is a distinct non-virion protein that shows no similarities to proteins in current databases: it induces plasmalemma deposits over plasmadesmata (PD) pit fields and is speculated to have roles in LIYV virion transport within infected plants. In this study, P26 was demonstrated to be a PD-localized protein, and its biological significance was testedin plantaby mutagenesis analysis. An LIYV P26 knockout mutant (P26X) showed viral RNA replication and virion formation in inoculated leaves ofNicotiana benthamianaplants, but failed to give systemic infection. Confirmation by using a modified green fluorescent protein (GFP)-tagged LIYV P26X showed GFP accumulation only in infiltrated leaf tissues, while wild-type LIYV GFP readily spread systemically in the phloem. Attempts to rescue P26X by complementation intranswere negative. However a translocated LIYV P26 gene in the LIYV genome rescued systemic infection, but P26 orthologs from other criniviruses did not. Mutagenesisin plantaassays showed that deletions in P26, as well as 2 of 11 specific alanine-scanning mutants, abolished the ability to systemically infectN. benthamiana.IMPORTANCEPlant viruses encode specific proteins that facilitate their ability to establish multicellular/systemic infections in their host plants. Relatively little is known of the transport mechanisms for plant viruses whose infections are phloem limited, including those of the familyClosteroviridae.These viruses have complex, long filamentous virions that spread through the phloem.Lettuce infectious yellows virus(LIYV) encodes a non-virion protein, P26, which forms plasmalemma deposits over plasmodesmata pit fields, and LIYV virions are consistently found attached to those deposits. Here we demonstrate that P26 is a unique movement protein required for LIYV systemic infection in plants. LIYV P26 shows no sequence similarities to other proteins, but other criniviruses encode P26 orthologs. However, these failed to complement movement of LIYV P26 mutants.

scholarly journals Comparative Pathogenicity of United Kingdom Isolates of the Emerging Pathogen Candida auris and Other Key Pathogenic Candida Species

mSphere ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Andrew M. Borman ◽  
Adrien Szekely ◽  
Elizabeth M. Johnson
Keyword(s):  
Invasive Candidiasis ◽  
Fungal Pathogen ◽  
Galleria Mellonella ◽  
Systemic Infection ◽  
Mortality Rates ◽  
Infection Model ◽  
Candida Auris ◽  
Deep Tissue ◽  
Content Type

ABSTRACT The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show strain-specific differences in the virulence of C. auris, with the most virulent isolates exhibiting pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus. Candida auris, first described in 2009, has since emerged as an important, multidrug-resistant, nosocomial agent of candidemia, with large outbreaks reported worldwide and high mortality rates associated with therapeutic failure. The current study employed C. auris isolates from a variety of centers in the United Kingdom to evaluate the pathogenicity of this emerging pathogen compared to that of other common pathogenic yeast species in the invertebrate Galleria mellonella infection model. We showed that C. auris isolates differ in their growth characteristics in vitro, with a proportion of isolates failing to release daughter cells after budding, resulting in the formation of large aggregates of cells that cannot be physically disrupted. Our results also demonstrate strain-specific differences in the behavior of C. auris in G. mellonella, with the aggregate-forming isolates exhibiting significantly less pathogenicity than their nonaggregating counterparts. Importantly, the nonaggregating isolates exhibited pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus, despite the fact that C. auris isolates do not produce hyphae and produce only rudimentary pseudohyphae either in vitro or in G. mellonella. IMPORTANCE The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show strain-specific differences in the virulence of C. auris, with the most virulent isolates exhibiting pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus.

scholarly journals FEDS: a Novel Fluorescence-Based High-Throughput Method for Measuring DNA Supercoiling In Vivo

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Alexandre Duprey ◽  
Eduardo A. Groisman
Keyword(s):  
High Throughput ◽  
Fluorescent Protein ◽  
Single Cells ◽  
Internal Standard ◽  
Population Level ◽  
Dna Supercoiling ◽  
Content Type ◽  
Regulatory Loop ◽  
Green Fluorescent

ABSTRACT DNA supercoiling (DS) is essential for life because it controls critical processes, including transcription, replication, and recombination. Current methods to measure DNA supercoiling in vivo are laborious and unable to examine single cells. Here, we report a method for high-throughput measurement of bacterial DNA supercoiling in vivo. Fluorescent evaluation of DNA supercoiling (FEDS) utilizes a plasmid harboring the gene for a green fluorescent protein transcribed by a discovered promoter that responds exclusively to DNA supercoiling and the gene for a red fluorescent protein transcribed by a constitutive promoter as the internal standard. Using FEDS, we uncovered single-cell heterogeneity in DNA supercoiling and established that, surprisingly, population-level decreases in DNA supercoiling result from a low-mean/high-variance DNA supercoiling subpopulation rather than from a homogeneous shift in supercoiling of the whole population. In addition, we identified a regulatory loop in which a gene that decreases DNA supercoiling is transcriptionally repressed when DNA supercoiling increases. IMPORTANCE DNA represents the chemical support of genetic information in all forms of life. In addition to its linear sequence of nucleotides, it bears critical information in its structure. This information, called DNA supercoiling, is central to all fundamental DNA processes, such as transcription and replication, and defines cellular physiology. Unlike reading of a nucleotide sequence, DNA supercoiling determinations have been laborious. We have now developed a method for rapid measurement of DNA supercoiling and established its utility by identifying a novel regulator of DNA supercoiling in the bacterium Salmonella enterica as well as behaviors that could not have been discovered with current methods.

scholarly journals Seed Transmission of Fusarium verticillioides in Maize Plants Grown Under Three Different Temperature Regimes

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1109-1115 ◽  
Author(s):  
A. L. Wilke ◽  
C. R. Bronson ◽  
A. Tomas ◽  
G. P. Munkvold
Keyword(s):  
Temperature Regime ◽  
Fluorescent Protein ◽  
Fusarium Verticillioides ◽  
Systemic Infection ◽  
Seed Transmission ◽  
Infection Process ◽  
Effect Of Temperature ◽  
Growth Stages ◽  
Temperature Regimes ◽  
Green Fluorescent

Fusarium verticillioides can be seed transmitted and cause systemic infection of maize; however, the frequency of these phenomena has varied widely among and within individual studies. In order to better understand this variability, we evaluated the effect of temperature on the first step in the systemic infection process, the transmission of F. verticillioides from seed to seedling. Seed of a commercial maize hybrid were inoculated with a strain of F. verticillioides that had been transformed with a gene for green fluorescent protein (GFP). The seed were planted in a greenhouse potting mix and incubated in growth chambers. Plants were incubated at one of three temperature regimes designed to simulate average and extreme temperatures occurring in Iowa during the weeks following planting. Root, mesocotyl, and stem tissues were sampled at growth stages V2 and V6, surface disinfested, and cultured on a semiselective medium. At V2, >90% of root and mesocotyl tissues was infected by the GFP-expressing strain at all three temperature regimes. Also at V2, infection was detected in 68 to 75% of stems. At V6, infection of root and mesocotyl tissues persisted and was detected in 97 to 100% of plants at all three temperature regimes. Plants also had symptomless systemic infection of belowground and aboveground internodes at V6. Infection of the three basal aboveground internodes was 24, 6, and 3% for the low-temperature regime; 35, 9, and 0% for the average-temperature regime; and 46, 24, and 9% for the high-temperature regime. Seed transmission and systemic infection occurred at all temperatures and did not differ significantly among treatments. These results indicate that, if maize seed is infected with F. verticillioides, seed transmission is common and symptomless systemic infection can be initiated under a broad range of temperature conditions.

scholarly journals Colonization of Cecum Is Important for Development of Persistent Infection by Yersinia pseudotuberculosis

2014 ◽  
Vol 82 (8) ◽  
pp. 3471-3482 ◽  
Author(s):  
Anna Fahlgren ◽  
Kemal Avican ◽  
Linda Westermark ◽  
Roland Nordfelth ◽  
Maria Fällman
Keyword(s):  
Persistent Infection ◽  
Yersinia Pseudotuberculosis ◽  
Single Cells ◽  
Acute Infection ◽  
Systemic Infection ◽  
Immune Defense ◽  
Infection Model ◽  
Bacterial Persistence ◽  
Content Type ◽  
Infection Period

ABSTRACTYersiniosis is a human disease caused by the bacteriumYersinia pseudotuberculosisorYersinia enterocolitica. The infection is usually resolved but can lead to postinfectious sequelae, including reactive arthritis and erythema nodosum. The commonly usedYersiniamouse infection model mimics acute infection in humans to some extent but leads to systemic infection and eventual death. Here, we analyzed sublethal infection doses ofY. pseudotuberculosisin mice in real time using bioluminescent imaging and found that infections using these lower doses result in extended periods of asymptomatic infections in a fraction of mice. In a search for the site for bacterial persistence, we found that the cecum was the primary colonization site and was the site where the organism resided during a 115-day infection period. Persistent infection was accompanied by sustained fecal shedding of cultivable bacteria. Cecal patches were identified as the primary site for cecal colonization during persistence.Y. pseudotuberculosisbacteria were present in inflammatory lesions, in localized foci, or as single cells and also in neutrophil exudates in the cecal lumen. The chronically colonized cecum may serve as a reservoir for dissemination of infection to extraintestinal sites, and a chronic inflammatory state may trigger the onset of postinfectious sequelae. This novel mouse model for bacterial persistence in cecum has potential as an investigative tool to unveil a deeper understanding of bacterial adaptation and host immune defense mechanisms during persistent infection.

scholarly journals Shift in Ribonucleotide Reductase Gene Expression in Pseudomonas aeruginosa during Infection

2011 ◽  
Vol 79 (7) ◽  
pp. 2663-2669 ◽  
Author(s):  
Britt-Marie Sjöberg ◽  
Eduard Torrents
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescent Protein ◽  
Process Analysis ◽  
Interaction Model ◽  
Infection Process ◽  
Content Type ◽  
Novel Drugs ◽  
Reductase Gene ◽  
Environmental Requirements ◽  
Green Fluorescent

ABSTRACTThe roles of different ribonucleotide reductases (RNRs) in bacterial pathogenesis have not been studied systematically. In this work we analyzed the importance of the differentPseudomonas aeruginosaRNRs in pathogenesis using theDrosophila melanogasterhost-pathogen interaction model.P. aeruginosacodes for three different RNRs with different environmental requirements. Class II and III RNR chromosomal mutants exhibited reduced virulence in this model. Translational reporter fusions of RNR genenrdA,nrdJ, ornrdDto the green fluorescent protein were constructed to measure the expression of each class during the infection process. Analysis of theP. aeruginosainfection by flow cytometry revealed increased expression ofnrdJandnrdDand decreasednrdAexpression during the infection process. Expression of each RNR class fits with the pathogenicities of the chromosomal deletion mutants. An extended understanding of the pathogenicity and physiology ofP. aeruginosawill be important for the development of novel drugs against infections in cystic fibrosis patients.

scholarly journals Effect of the Surfactant Tween 80 on the Detachment and Dispersal of Salmonella enterica Serovar Thompson Single Cells and Aggregates from Cilantro Leaves as Revealed by Image Analysis

2014 ◽  
Vol 80 (16) ◽  
pp. 5037-5042 ◽  
Author(s):  
Maria T. Brandl ◽  
Steven Huynh
Keyword(s):  
Image Analysis ◽  
Salmonella Enterica ◽  
Fluorescent Protein ◽  
Single Cells ◽  
Leaf Tissue ◽  
Aggregate Size ◽  
Population Level ◽  
Tween 80 ◽  
Content Type ◽  
Plate Counts

ABSTRACTSalmonella entericahas the ability to form biofilms and large aggregates on produce surfaces, including on cilantro leaves. Aggregates ofS. entericaserovar Thompson that remained attached to cilantro leaves after rigorous washing and that were present free or bound to dislodged leaf tissue in the wash suspension were observed by confocal microscopy. Measurement ofS.Thompson population sizes in the leaf washes by plate counts failed to show an effect of 0.05% Tween 80 on the removal of the pathogen from cilantro leaves 2 and 6 days after inoculation. On the contrary, digital image analysis of micrographs of single cells and aggregates of green fluorescent protein (GFP)-S.Thompson present in cilantro leaf washes revealed that single cells represented 13.7% of the cell assemblages in leaf washes containing Tween 80, versus 9.3% in those without the surfactant. Moreover, Tween 80 decreased the percentage of the totalS.Thompson cell population located in aggregates equal to or larger than 64 cells from 9.8% to 4.4% (P< 0.05). Regression analysis of the frequency distribution of aggregate size in leaf washes with and without Tween 80 showed that the surfactant promoted the dispersal of cells from large aggregates into smaller ones and into single cells (P< 0.05). Our study underlines the importance of investigating bacterial behavior at the scale of single cells in order to uncover trends undetectable at the population level by bacterial plate counts. Such an approach may provide valuable information to devise strategies aimed at enhancing the efficacy of produce sanitization treatments.

scholarly journals Imaging and Analysis of Pseudomonas aeruginosa Swarming and Rhamnolipid Production

2011 ◽  
Vol 77 (23) ◽  
pp. 8310-8317 ◽  
Author(s):  
Joshua D. Morris ◽  
Jessica L. Hewitt ◽  
Lawrence G. Wolfe ◽  
Nachiket G. Kamatkar ◽  
Sarah M. Chapman ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescent Protein ◽  
Nile Red ◽  
Temporal Distribution ◽  
Time Lapse ◽  
Content Type ◽  
Rhamnolipid Production ◽  
Serovar Typhimurium ◽  
Surface Motility ◽  
Green Fluorescent

ABSTRACTMany bacteria spread over surfaces by “swarming” in groups. A problem for scientists who study swarming is the acquisition of statistically significant data that distinguish two observations or detail the temporal patterns and two-dimensional heterogeneities that occur. It is currently difficult to quantify differences between observed swarm phenotypes. Here, we present a method for acquisition of temporal surface motility data using time-lapse fluorescence and bioluminescence imaging. We specifically demonstrate three applications of our technique with the bacteriumPseudomonas aeruginosa. First, we quantify the temporal distribution ofP. aeruginosacells tagged with green fluorescent protein (GFP) and the surfactant rhamnolipid stained with the lipid dye Nile red. Second, we distinguish swarming ofP. aeruginosaandSalmonella entericaserovar Typhimurium in a coswarming experiment. Lastly, we quantify differences in swarming and rhamnolipid production of severalP. aeruginosastrains. While the best swarming strains produced the most rhamnolipid on surfaces, planktonic culture rhamnolipid production did not correlate with surface growth rhamnolipid production.

Monostotic fibrous dysplasia of the thoracic spine: clinopathological description and follow up

2004 ◽  
Vol 100 (4) ◽  
pp. 378-381 ◽  
Author(s):  
Mehmet Arazi ◽  
Onder Guney ◽  
Mustafa Ozdemir ◽  
Omer Uluoglu ◽  
Nuket Uzum
Keyword(s):  
Fibrous Dysplasia ◽  
Thoracic Spine ◽  
Histopathological Examination ◽  
En Bloc Resection ◽  
Spinal Tumors ◽  
En Bloc ◽  
Content Type ◽  
Thoracic Spinal ◽  
Fine Print

✓ The authors report the case of a 53-year-old woman with monostotic fibrous dysplasia of the thoracic spine. The patient presented with a 1-month history of pain in the thoracic spinal region. En bloc resection of the lesion was successfully performed via a transthoracic approach, and a histopathological examination confirmed the diagnosis of fibrous dysplasia. At 24-month follow-up examination, pain and vertebral instability were absent. The findings in this case illustrate that, although very rare, monostotic fibrous dysplasia of the thoracic spine should be considered in the differential diagnosis of spinal tumors. Although a consensus for management of this disease has not been achieved, the authors recommend radical removal of all involved bone as well as internal fixation or bone graft—assisted fusion to achieve long-term stabilization.

scholarly journals Vibrio cholerae Triggers SOS and Mutagenesis in Response to a Wide Range of Antibiotics: a Route towards Multiresistance

2011 ◽  
Vol 55 (5) ◽  
pp. 2438-2441 ◽  
Author(s):  
Zeynep Baharoglu ◽  
Didier Mazel
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Vibrio Cholerae ◽  
Fluorescent Protein ◽  
Resistance Development ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Green Fluorescent ◽  
Regulated Promoters

ABSTRACTAntibiotic resistance development has been linked to the bacterial SOS stress response. InEscherichia coli, fluoroquinolones are known to induce SOS, whereas other antibiotics, such as aminoglycosides, tetracycline, and chloramphenicol, do not. Here we address whether various antibiotics induce SOS inVibrio cholerae. Reporter green fluorescent protein (GFP) fusions were used to measure the response of SOS-regulated promoters to subinhibitory concentrations of antibiotics. We show that unlike the situation withE. coli, all these antibiotics induce SOS inV. cholerae.

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