scholarly journals Cocultures of Peronospora tabacina and Nicotiana Species to Study Host-Pathogen Interactions

2001 ◽  
Vol 91 (12) ◽  
pp. 1224-1230 ◽  
Author(s):  
E. P. Heist ◽  
W. C. Nesmith ◽  
C. L. Schardl
Keyword(s):  
Nicotiana Tabacum ◽  
Total Darkness ◽  
Blue Mold ◽  
Peronospora Tabacina ◽  
Genetic Studies ◽  
Free System ◽  
Light Regimes ◽  
Intact Plants ◽  
Reliable Source

Long-term cocultures of the tobacco blue mold pathogen, Peronospora tabacina, with Nicotiana tabacum and N. repanda callus were derived from infected host plant tissue. In this apparently contaminant-free system, sporulation occurred under similar conditions as in intact plants. Sporangia were collected from cocultures and used to complete Koch's postulates. The cocultures were grown under two light regimes. One consisted of 23 h of light followed by 1 h of darkness and the second comprised total darkness. Sporulation occurred frequently in the 23 h light-grown cocultures but resulted in production of abnormal sporangiophores and sporangia. Production of normal sporangiophores and sporangia was achieved by transferring light-grown cocultures to overnight darkness and resulted in necrosis of the callus. Cocultures of Peronospora tabacina with either host species, grown in total darkness, frequently sporulated with minimal necrosis over the course of 1 year. Thus, cocultures should prove useful as a source of Peronospora tabacina over extended periods of time at low risk of pathogen release, for studying the physiology of Peronospora tabacina- Nicotiana interactions, maintaining Peronospora tabacina lines for genetic studies, and providing a reliable source of axenic inoculum for research.

scholarly journals Actigard Increases Fungicide Efficacy Against Tobacco Blue Mold

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1463-1467 ◽  
Author(s):  
J. A. LaMondia
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Mold ◽  
Marketable Yield ◽  
Peronospora Tabacina ◽  
The Third ◽  
Combination Treatments ◽  
Fungicide Efficacy

Blue mold, caused by Peronospora tabacina, can be economically damaging to cigar wrapper tobacco (Nicotiana tabacum). We evaluated acibenzolar-S-methyl (ASM) as Actigard 50WG alone and in combination with a standard fungicide program for efficacy against blue mold on shade-grown cigar wrapper tobacco in Windsor, CT. The standard fungicide program consisted of dimethomorph (Acrobat MZ or Forum) plus mancozeb (Dithane), alternated with azoxystrobin (Quadris), and applied at label rates on six occasions at 14-day intervals. Treated and untreated 5-by-5-m plots were replicated four times in 2003, 2004, 2005, 2006, and 2007. ASM treatments were applied alone or in combination with fungicides at the third, fourth, and fifth spray dates at rates ranging from 1.1 to 17.5 g a.i./ha. Disease was greatest in nontreated plots and reduced in all fungicide, Actigard, or combination treatments. The combination of three ASM applications at rates of 17.5 g a.i./ha down to 4.4 g a.i./ha with the standard fungicide program was more efficacious than either fungicides or ASM alone (P < 0.001) in reducing the number of blue mold lesions per plot or number of diseased leaves harvested. The combination of fungicides and low rates of ASM (2.2 or 1.1 g a.i./ha) was similar to either fungicides or ASM (17.5 g a.i./ha) applied alone. Combining low rates of ASM with fungicide applications greatly increased efficacy and marketable yield.

scholarly journals Point-of-Use Detection of Environmental Fluoride via a Cell-Free Riboswitch-Based Biosensor

2019 ◽  
Author(s):  
Walter Thavarajah ◽  
Adam D. Silverman ◽  
Matthew S. Verosloff ◽  
Nancy Kelley-Loughnane ◽  
Michael C. Jewett ◽  
...  
Keyword(s):  
Water Source ◽  
Free System ◽  
Molecular Systems ◽  
Long Term Storage ◽  
Point Of Use ◽  
Regulatory Standard ◽  
A Cell ◽  
Global Concern ◽  
Dna Template

AbstractAdvances in biosensor engineering have enabled the design of programmable molecular systems to detect a range of pathogens, nucleic acids, and chemicals. Here, we engineer and field-test a biosensor for fluoride, a major groundwater contaminant of global concern. The sensor consists of a cell-free system containing a DNA template that encodes a fluoride-responsive riboswitch regulating genes that produce a fluorescent or colorimetric output. Individual reactions can be lyophilized for long-term storage and detect fluoride at levels above 2 parts per million, the EPA’s most stringent regulatory standard, in both laboratory and field conditions. Through onsite detection of fluoride in a real-world water source, this work provides a critical proof-of-principle for the future engineering of riboswitches and other biosensors to address challenges for global health and the environment.

scholarly journals Enhanced Glutathione Metabolism Is Correlated with Sulfur-Induced Resistance in Tobacco mosaic virus–Infected Genetically Susceptible Nicotiana tabacum Plants

2010 ◽  
Vol 23 (11) ◽  
pp. 1448-1459 ◽  
Author(s):  
Kerstin Höller ◽  
Lóránt Király ◽  
András Künstler ◽  
Maria Müller ◽  
Gábor Gullner ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Induced Resistance ◽  
Marker Gene ◽  
General Mechanism ◽  
Glutathione Metabolism ◽  
Tobacco Plants ◽  
Glutathione Biosynthesis

Sulfur-induced resistance, also known as sulfur-enhanced defense (SIR/SED) was investigated in Nicotiana tabacum cv. Samsun nn during compatible interaction with Tobacco mosaic virus (TMV) in correlation with glutathione metabolism. To evaluate the influence of sulfur nutritional status on virus infection, tobacco plants were treated with nutrient solutions containing either sufficient sulfate (+S) or no sulfate (−S). Sufficient sulfate supply resulted in a suppressed and delayed symptom development and diminished virus accumulation over a period of 14 days after inoculation as compared with −S conditions. Expression of the defense marker gene PR-1a was markedly upregulated in sulfate-treated plants during the first day after TMV inoculation. The occurrence of SIR/SED correlated with a higher level of activity of sulfate assimilation, cysteine, and glutathione metabolism in plants treated with sulfate. Additionally, two key genes involved in cysteine and glutathione biosynthesis (encoding adenosine 5′-phosphosulfate reductase and γ-glutamylcysteine synthetase, respectively) were upregulated within the first day after TMV inoculation under +S conditions. Sulfate withdrawal from the soil was accelerated at the beginning of the infection, whereas it declined in the long term, leading to an accumulation of sulfur in the soil of plants grown with sulfate. This observation could be correlated with a decrease in sulfur contents in TMV-infected leaves in the long term. In summary, this is the first study that demonstrates a link between the activation of cysteine and glutathione metabolism and the induction of SIR/SED during a compatible plant-virus interaction in tobacco plants, indicating a general mechanism behind SIR/SED.

scholarly journals Population structure and migration of the Tobacco Blue Mold Pathogen,Peronospora tabacina,into North America and Europe

2018 ◽  
Vol 27 (3) ◽  
pp. 737-751 ◽  
Author(s):  
Monica Blanco-Meneses ◽  
Ignazio Carbone ◽  
Jean B. Ristaino
Keyword(s):  
Population Structure ◽  
North America ◽  
Blue Mold ◽  
Peronospora Tabacina ◽  
And Migration

scholarly journals Comparative studies of underwater light regimes in lakes of the East-Suwałki Lakeland

2016 ◽  
Vol 16 (4) ◽  
pp. 173-183 ◽  
Author(s):  
Dariusz Borowiak ◽  
Magdalena Borowiak
Keyword(s):  
Optical Properties ◽  
Attenuation Coefficient ◽  
Suspended Solids ◽  
Trophic Status ◽  
Thermal Conditions ◽  
Secchi Disc ◽  
Eutrophic Lakes ◽  
Light Regimes ◽  
Interannual Fluctuations

Abstract Secchi disc transparency and optical properties of water, based on measurements for downward irradiance using an underwater radiometer PER-700, were studied in 23 lakes of the Suwałki Landscape Park (SLP) in 2013. Measurements of optically significant constituents of water were also performed (YSI EXO-2) and analysed. Data on water transparency from published studies were used to assess long-term changes in the optical conditions in the deepest water body in Poland – Lake Hańcza. In terms of the optical characteristics of the water, the analysed SLP lakes can essentially be divided into two distinct groups representing different optical lake types. These are optical categories of lakes most common in Poland, namely types II and IIIb. Regional equations describing the relationships between the attenuation coefficient for downward irradiance as well as optically significant constituents of water were developed. The optical properties of the SLP lakes are mainly affected by suspended solids, mostly phytoplankton. Interannual fluctuations in Sechi disc transparency, as well as the attenuation coefficient for downward irradiance and other apparent optical properties of mid-summer water calculated from it, are determined by the spring thermal conditions and intensity of phytoplankton blooms during this period. Application of the attenuation coefficient for downward irradiance as a criterion for the assessment of the trophic status of the SLP lakes indicates that these are generally eutrophic lakes. The largest and deepest lakes of the park, however, are mesotrophic. Lake Hańcza is currently in the stage of α-mesotrophy.

scholarly journals ABOUT TUBERCULOSIS MORBIDITY IN RUSSIA

2017 ◽  
Vol 1 (66) ◽  
pp. 29-33
Author(s):  
Виктор Катола ◽  
Viktor Katola
Keyword(s):  
Molecular Genetic ◽  
Amur Region ◽  
The Body ◽  
Genetic Studies ◽  
Adolescents And Adults

Based on the analysis of the long-term morbidity of tuberculosis in Russia and the Amur Region, it has been established that its uplifts are performed in cycles of 25-30 years. Taking into account the literature data and our own experiments, it is assumed that each successive outbreak of tuberculosis is caused by coincident activation of L-forms of mycobacteria contained in the body of vaccinated and revaccinated children, adolescents and adults, and by dermal phenotypes inhabiting various environmental sites. To identify the "hidden reserve of mycobacteria" it is recommended to use the method of prints and the transfer of bacteriological laboratories to molecular genetic studies.

scholarly journals Cryopreservation of Anopheles stephensi embryos

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Eric R. James ◽  
Yingda Wen ◽  
James Overby ◽  
Kristen Pluchino ◽  
Shane McTighe ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Infectious Diseases ◽  
Anopheles Stephensi ◽  
Mass Storage ◽  
Genetic Studies ◽  
Transgenic Lines ◽  
Cryopreservation Method ◽  
Anopheline Mosquitoes

AbstractThe ability to cryopreserve mosquitoes would revolutionize work on these vectors of major human infectious diseases by conserving stocks, new isolates, lab-bred strains, and transgenic lines that currently require continuous life cycle maintenance. Efforts over several decades to develop a method for cryopreservation have, until now, been fruitless: we describe here a method for the cryopreservation of Anopheles stephensi embryos yielding hatch rates of ~ 25%, stable for > 5 years. Hatched larvae developed into fertile, fecund adults and blood-fed females, produced fully viable second generation eggs, that could be infected with Plasmodium falciparum at high intensities. The key components of the cryopreservation method are: embryos at 15–30 min post oviposition, two incubation steps in 100% deuterated methanol at − 7 °C and − 14.5 °C, and rapid cooling. Eggs are recovered by rapid warming with concomitant dilution of cryoprotectant. Eggs of genetically modified A. stephensi and of A. gambiae were also successfully cryopreserved. This enabling methodology will allow long-term conservation of mosquitoes as well as acceleration of genetic studies and facilitation of mass storage of anopheline mosquitoes for release programs.

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