scholarly journals Root and Stem Infection of Rhododendron from Potting Medium Infested with Phytophthora ramorum

Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1265-1270 ◽  
Author(s):  
J. L. Parke ◽  
C. Lewis
Keyword(s):  
Phytophthora Ramorum ◽  
Epifluorescence Microscopy ◽  
Stem Infection ◽  
Splash Dispersal ◽  
Hair Roots ◽  
Potting Medium ◽  
Nursery Stock ◽  
Potting Media ◽  
Transmit Disease

Phytophthora ramorum has been detected in soil and potting media, but the potential for root infections is not fully understood. To determine whether the root system could become infected and transmit disease, rhododendron ‘Nova Zembla’ plants grown from rooted cuttings and native Pacific rhododendron (Rhododendron macrophyllum) plants grown from seed were transplanted into a potting medium artificially infested with P. ramorum. Inoculum consisted of V8-brothvermiculite cultures of P. ramorum, chopped infected leaves, or zoospores. Plants were watered from the bottom to prevent splash dispersal of inoculum onto stems and foliage. Both infested amendments and applications of zoospores resulted in plant mortality within 3 to 7 weeks. P. ramorum was isolated from hair roots, large roots, and stems above and below the potting medium surface. Noninoculated control plants remained healthy and did not yield P. ramorum. Epifluorescence microscopy of tissue culture plantlets inoculated in vitro revealed attraction of zoospores to wounds and root primordia, and colonization of the cortex and vascular tissues of roots and stems, including the xylem. Transmission of P. ramorum from infested potting media to stems via infected, symptomless root tissue demonstrates the need to monitor potting media for presence of the pathogen to prevent spread of P. ramorum on nursery stock.

scholarly journals Eradication of Phytophthora ramorum and Other Pathogens from Potting Medium or Soil by Treatment with Aerated Steam or Fumigation with Metam Sodium

2008 ◽  
Vol 18 (1) ◽  
pp. 106-110 ◽  
Author(s):  
R.G. Linderman ◽  
E.A. Davis
Keyword(s):  
Infected Plant ◽  
Selective Medium ◽  
Phytophthora Ramorum ◽  
Steam Treatment ◽  
Infested Soil ◽  
Pythium Irregulare ◽  
Metam Sodium ◽  
Potting Medium ◽  
Potting Media ◽  
Polyethylene Bags

Phytophthora ramorum survived in potting media infested with sporangia or chlamydospores, allowing the pathogen to remain undetected while disseminated geographically. Chlamydospores or oospores of P. ramorum, Pythium irregulare, Thielaviopsis basicola, and Cylindrocladium scoparium produced in vermiculite culture were used to infest potting media. Infested media in plastic plug flats were treated with aerated steam mixtures from 45 to 70 °C for 30 min. In a second experiment, infested media were fumigated in polyethylene bags with a concentration series of metam sodium ranging from 0.25 to 1.0 mL·L−1. Survival of the pathogens was determined by selective baiting or direct plating the infested media on PARP selective medium. Assays indicated that all pathogens in the infested potting media were killed by aerated steam heat treatments of 50 °C or higher. Metam sodium concentrations of 1.0 mL·L−1 of medium or greater also eradicated all pathogens from the potting medium and soil. These results show that aerated steam treatment or fumigation with metam sodium can effectively sanitize soil-less potting media infested with P. ramorum or other soilborne pathogens, as well as P. ramorum-infested soil beneath infected plant containers. In addition, steam treatments to 70 °C did not melt plastic plug trays.

scholarly journals Sample-Pooling Strategy for SARS-CoV-2 Detection among Students and Staff of the University of Sannio

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1166
Author(s):  
Immacolata Polvere ◽  
Elena Silvestri ◽  
Lina Sabatino ◽  
Antonia Giacco ◽  
Stefania Iervolino ◽  
...  
Keyword(s):  
Quantitative Polymerase Chain Reaction ◽  
Virus Detection ◽  
Testing Procedures ◽  
Stem Infection ◽  
In Vitro Diagnostic ◽  
Sample Pooling ◽  
Pooling Strategy ◽  
Asymptomatic Individuals ◽  
The University

Since the beginning of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic, it has been clear that testing large groups of the population was the key to stem infection and prevent the effects of the coronavirus disease of 2019, mostly among sensitive patients. On the other hand, time and cost-sustainability of virus detection by molecular analysis such as reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) may be a major issue if testing is extended to large communities, mainly asymptomatic large communities. In this context, sample-pooling and test grouping could offer an effective solution. Here we report the screening on 1195 oral-nasopharyngeal swabs collected from students and staff of the Università degli Studi del Sannio (University of Sannio, Benevento, Campania, Italy) and analyzed by an in-house developed multiplex RT-qPCR for SARS-CoV-2 detection through a simple monodimensional sample pooling strategy. Overall, 400 distinct pools were generated and, within 24 h after swab collection, five positive samples were identified. Out of them, four were confirmed by using a commercially available kit suitable for in vitro diagnostic use (IVD). High accuracy, sensitivity and specificity were also determined by comparing our results with a reference IVD assay for all deconvoluted samples. Overall, we conducted 463 analyses instead of 1195, reducing testing resources by more than 60% without lengthening diagnosis time and without significant losses in sensitivity, suggesting that our strategy was successful in recognizing positive cases in a community of asymptomatic individuals with minor requirements of reagents and time when compared to normal testing procedures.

scholarly journals A prospectus of plant growth promoting endophytic bacterium from orchid (Vanda cristata)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sujit Shah ◽  
Krishna Chand ◽  
Bhagwan Rekadwad ◽  
Yogesh S. Shouche ◽  
Jyotsna Sharma ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Colonization ◽  
Endophytic Bacterium ◽  
Epifluorescence Microscopy ◽  
In Vitro Cultivation ◽  
Rrna Gene ◽  
Bacillus Spp ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract Background A plant growth-promoting endophytic bacterium PVL1 isolated from the leaf of Vanda cristata has the ability to colonize with roots of plants and protect the plant. PVL1 was isolated using laboratory synthetic media. 16S rRNA gene sequencing method has been employed for identification before and after root colonization ability. Results Original isolated and remunerated strain from colonized roots were identified as Bacillus spp. as per EzBiocloud database. The presence of bacteria in the root section of the plantlet was confirmed through Epifluorescence microscopy of colonized roots. The in-vitro plantlet colonized by PVL1 as well as DLMB attained higher growth than the control. PVL1 capable of producing plant beneficial phytohormone under in vitro cultivation. HPLC and GC-MS analysis suggest that colonized plants contain Indole Acetic Acid (IAA). The methanol extract of Bacillus spp., contains 0.015 μg in 1 μl concentration of IAA. PVL1 has the ability to produce antimicrobial compounds such as ethyl iso-allocholate, which exhibits immune restoring property. One-way ANOVA shows that results were statistically significant at P ≤ 0.05 level. Conclusions Hence, it has been concluded that Bacillus spp. PVL1 can promote plant growth through secretion of IAA during root colonization and ethyl iso-allocholate to protect plants from foreign infections. Thus, this study supports to support Koch’s postulates of bacteria establishment.

scholarly journals Multi-Omics Study of Keystone Species in a Cystic Fibrosis Microbiome

2021 ◽  
Vol 22 (21) ◽  
pp. 12050
Author(s):  
Cynthia B. Silveira ◽  
Ana G. Cobián-Güemes ◽  
Carla Uranga ◽  
Jonathon L. Baker ◽  
Anna Edlund ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Lung Function ◽  
Sequence Data ◽  
Anaerobic Bacteria ◽  
Keystone Species ◽  
Clinical Diagnostics ◽  
Epifluorescence Microscopy ◽  
Fermentation Products ◽  
Degrading Bacteria

Ecological networking and in vitro studies predict that anaerobic, mucus-degrading bacteria are keystone species in cystic fibrosis (CF) microbiomes. The metabolic byproducts from these bacteria facilitate the colonization and growth of CF pathogens like Pseudomonas aeruginosa. Here, a multi-omics study informed the control of putative anaerobic keystone species during a transition in antibiotic therapy of a CF patient. A quantitative metagenomics approach combining sequence data with epifluorescence microscopy showed that during periods of rapid lung function loss, the patient’s lung microbiome was dominated by the anaerobic, mucus-degrading bacteria belonging to Streptococcus, Veillonella, and Prevotella genera. Untargeted metabolomics and community cultures identified high rates of fermentation in these sputa, with the accumulation of lactic acid, citric acid, and acetic acid. P. aeruginosa utilized these fermentation products for growth, as indicated by quantitative transcriptomics data. Transcription levels of P. aeruginosa genes for the utilization of fermentation products were proportional to the abundance of anaerobic bacteria. Clindamycin therapy targeting Gram-positive anaerobes rapidly suppressed anaerobic bacteria and the accumulation of fermentation products. Clindamycin also lowered the abundance and transcription of P. aeruginosa, even though this patient’s strain was resistant to this antibiotic. The treatment stabilized the patient’s lung function and improved respiratory health for two months, lengthening by a factor of four the between-hospitalization time for this patient. Killing anaerobes indirectly limited the growth of P. aeruginosa by disrupting the cross-feeding of fermentation products. This case study supports the hypothesis that facultative anaerobes operated as keystone species in this CF microbiome. Personalized multi-omics may become a viable approach for routine clinical diagnostics in the future, providing critical information to inform treatment decisions.

scholarly journals Protein Expression Knockdown in Cancer Cells Induced by a Gemini Cationic Lipid Nanovector with Histidine-Based Polar Heads

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 791 ◽  
Author(s):  
Natalia Sánchez-Arribas ◽  
María Martínez-Negro ◽  
Eva M. Villar ◽  
Lourdes Pérez ◽  
José Osío Barcina ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Cationic Lipid ◽  
Positive Control ◽  
Lyotropic Liquid Crystal ◽  
Epifluorescence Microscopy ◽  
Biophysical Characterization ◽  
Multidisciplinary Study ◽  
Liquid Chromatography Tandem Mass ◽  
High Gene

A histidine-based gemini cationic lipid, which had already demonstrated its efficiency as a plasmid DNA (pDNA) nanocarrier, has been used in this work to transfect a small interfering RNA (siRNA) into cancer cells. In combination with the helper lipid monoolein glycerol (MOG), the cationic lipid was used as an antiGFP-siRNA nanovector in a multidisciplinary study. Initially, a biophysical characterization by zeta potential (ζ) and agarose gel electrophoresis experiments was performed to determine the lipid effective charge and confirm siRNA compaction. The lipoplexes formed were arranged in Lα lamellar lyotropic liquid crystal phases with a cluster-type morphology, as cryo-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS) studies revealed. Additionally, in vitro experiments confirmed the high gene knockdown efficiency of the lipid-based nanovehicle as detected by flow cytometry (FC) and epifluorescence microscopy, even better than that of Lipofectamine2000*, the transfecting reagent commonly used as a positive control. Cytotoxicity assays indicated that the nanovector is non-toxic to cells. Finally, using nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS), apolipoprotein A-I and A-II followed by serum albumin were identified as the proteins with higher affinity for the surface of the lipoplexes. This fact could be beyond the remarkable silencing activity of the histidine-based lipid nanocarrier herein presented.

scholarly journals Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Erik T. Sandbakken ◽  
Eivind Witsø ◽  
Bjørnar Sporsheim ◽  
Kjartan W. Egeberg ◽  
Olav A. Foss ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Laser Scanning Microscopy ◽  
Epifluorescence Microscopy ◽  
Variable Effect ◽  
Prosthetic Joint Infections ◽  
Before And After ◽  
Vitro Model

Abstract Background In cases of prosthetic joint infections, culture of sonication fluid can supplement culture of harvested tissue samples for correct microbial diagnosis. However, discrepant results regarding the increased sensitivity of sonication have been reported in several studies. To what degree bacteria embedded in biofilm are dislodged during the sonication process has to our knowledge not been fully elucidated. In the present in vitro study, we have evaluated the effect of sonication as a method to dislodge biofilm by quantitative microscopy. Methods We used a standard biofilm method to cover small steel plates with biofilm forming Staphylococcus epidermidis ATCC 35984 and carried out the sonication procedure according to clinical practice. By comparing area covered with biofilm before and after sonication with epifluorescence microscopy, the effect of sonication on biofilm removal was quantified. Two series of experiments were made, one with 24-h biofilm formation and another with 72-h biofilm formation. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to confirm whether bacteria were present after sonication. In addition, quantitative bacteriology of sonication fluid was performed. Results Epifluorescence microscopy enabled visualization of biofilm before and after sonication. CLSM and SEM confirmed coccoid cells on the surface after sonication. Biofilm was dislodged in a highly variable manner. Conclusion There is an unexpected high variation seen in the ability of sonication to dislodge biofilm-embedded S. epidermidis in this in vitro model.

In vivo visualization of oxygen transport in microvascular network

1994 ◽  
Vol 267 (5) ◽  
pp. H2068-H2078 ◽  
Author(s):  
T. Itoh ◽  
K. Yaegashi ◽  
T. Kosaka ◽  
T. Kinoshita ◽  
T. Morimoto
Keyword(s):  
Oxygen Transport ◽  
Time Lag ◽  
Epifluorescence Microscopy ◽  
Oxygen Quenching ◽  
Microvascular Network ◽  
Membrane Technique ◽  
Po2 Measurement ◽  
Micropositioning System

Oxygen transport from the blood to the tissues is a diffusive process driven by the gradient of oxygen tension (PO2). We developed an oxygen-quenching fluorescent membrane that allowed visualization of the PO2 distribution near the microvessels as optical patterns on the membrane by epifluorescence microscopy. This membrane was highly gas permeable to allow PO2 measurement and was transparent enough to also permit observation of the microcirculation. In combination with a newly devised gastight chamber and a micropositioning system, this membrane technique made it possible to visualize the PO2 distribution in the rat mesenteric microvascular network under well-defined conditions. Our preliminary findings indicate that the oxygen distribution in the microvascular network is heterogeneous and suggest that there is considerable release of oxygen from the arterioles. The time lag of the system for tracking rapid PO2 changes in vitro was shown to be negligible, indicating that dynamic PO2 changes occurring in vivo can also be assessed. This technique should provide a novel tool for the study of oxygen transport and metabolism under normal and abnormal conditions.

Growth and sporulation of Phytophthora ramorum in vitro in response to temperature and light

Mycologia ◽  
2006 ◽  
Vol 98 (3) ◽  
pp. 365-373 ◽  
Author(s):  
Larry Englander ◽  
Marsha Browning ◽  
Paul W. Tooley
Keyword(s):  
Phytophthora Ramorum ◽  
Response To Temperature

In vitro leaf inoculation studies as an indication of tree foliage susceptibility to Phytophthora ramorum in the UK

2005 ◽  
Vol 54 (4) ◽  
pp. 512-521 ◽  
Author(s):  
S. Denman ◽  
S. A. Kirk ◽  
C. M. Brasier ◽  
J. F. Webber
Keyword(s):  
Phytophthora Ramorum ◽  
The Uk ◽  
Tree Foliage

scholarly journals Disease on Nursery Stock as Affected by Environmental Factors and Seasonal Inoculum Levels of Phytophthora ramorum in Stream Water Used for Irrigation

Plant Disease ◽  
2008 ◽  
Vol 92 (11) ◽  
pp. 1566-1573 ◽  
Author(s):  
S. A. Tjosvold ◽  
D. L. Chambers ◽  
S. T. Koike ◽  
S. R. Mori
Keyword(s):  
Stream Water ◽  
Disease Incidence ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Nursery Stock ◽  
Stream Sampling ◽  
Flow Through ◽  
High Concentrations ◽  
Electronic Sensors ◽  
Native Host

A pear bait monitoring system was used to detect and quantify Phytophthora ramorum propagules in streams that flow through woodland areas with sudden oak death in Santa Cruz County, CA from 2001 to 2007. Stream propagules were detected most frequently or occurred in highest concentrations in winter and spring. The stream propagule concentration was characterized with statistical models using temperature and rainfall variables from 2004 to 2007. The highest concentrations of propagules occurred when stream sampling was preceded by about 2 months with low maximum daily temperatures and by 4 days with high rainfall. The occurrence of propagules in streams in the summer was mostly associated with infected leaves from the native host Umbellaria californica that prematurely abscised and fell into the water. When the stream water was used for irrigating rhododendron nursery stock from 2004 to 2007, disease occurred only three times in the two wettest springs (2005 and 2006) on plants sprinkler irrigated with stream water with relatively high concentrations of propagules. Disease incidence was described with a statistical model using the concentration of infective propagules as measured by pear baiting and consecutive hours of leaf wetness measured by electronic sensors at rhododendron height. The concentration of infective propagules was significantly reduced after water was pumped from the stream and applied through sprinklers.

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