scholarly journals Oscillating-flow Thermal Gradient PCR

2019 ◽  
Author(s):  
Varun L. Kopparthy ◽  
Niel D. Crews
Keyword(s):  
Thermal Gradient ◽  
Oscillating Flow ◽  
Gradient System ◽  
Rna Amplification ◽  
Dna And Rna ◽  
Simultaneous Acquisition ◽  
Phage Dna ◽  
Nucleic Acid Analysis ◽  
Microscope Slides ◽  
Glass Microscope

ABSTRACTWe report the development of a versatile system based on oscillating-flow methodology in a thermal gradient system for nucleic acid analysis. Analysis of DNA and RNA samples were performed in the device, without additional temperature control and complexity. The technique reported in this study eliminates the need for predetermined fluidic channels for thermocycles, and complexity involved with additional incubation steps required for RNA amplification. A microfluidic device was fabricated using rapid prototyping by simply sandwiching dual side adhesive Kapton tape and a PDMS spacer between glass microscope slides. Amplification of the 181-bp segment of a viral phage DNA (ΦX174) and B2M gene in human RNA samples was demonstrated using the system. The developed system enables simultaneous acquisition of amplification and melt curves, eliminating the need for post-processing.

The disposition of benzo(a)pyrene in the periphyton communities of two South Carolina streams: uptake and biotransformation

1982 ◽  
Vol 60 (10) ◽  
pp. 2084-2091 ◽  
Author(s):  
Mary G. Bruno ◽  
Timothy E. Fannin ◽  
Gordon J. Leversee
Keyword(s):  
South Carolina ◽  
Slide Surface ◽  
Uptake Rates ◽  
Area Basis ◽  
Autoradiographic Analysis ◽  
Colonization Time ◽  
Microscope Slides ◽  
Surface Area Basis ◽  
Glass Microscope ◽  
Sheath Material

The effect of periphyton community composition and colonization time on the uptake and biotransformation of benzo(a)pyrene (BaP) was determined in laboratory studies. Naturally colonized glass microscope slides were collected after 3 and 6 weeks from Castor Creek, which has a predominantly desmid flora, and after 3 and 5 weeks from diatom-dominated Upper Three Runs Creek. When expressed on a slide surface-area basis, the Castor Creek periphyton showed significantly greater BaP uptake rates at both colonization periods. Within streams, uptake rates increased significantly with colonization time. Autoradiographic analysis suggests that BaP was accumulated by surface sorption, especially to gelatinous sheath material. Active biotransformation as measured by the percentage extractable non-BaP 14C was not detected in either community.

Photolytic degradation of 2,4-D onZea maysleaves

Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 262-269 ◽  
Author(s):  
Ramarao Venkatesh ◽  
S. Kent Harrison
Keyword(s):  
Zea Mays ◽  
Time Course ◽  
Uv Light ◽  
Light Regime ◽  
Growth Chamber ◽  
Polychromatic Light ◽  
Photolytic Degradation ◽  
Microscope Slides ◽  
Glass Microscope

Growth chamber experiments were conducted to determine the effects of UV light and riboflavin on photolysis of 2,4-D applied toZea maysleaves. Droplets of 100 mg L−114C-2,4-D were applied toZ. maysleaves with and without 10 mg L−13H-riboflavin and exposed to either UV-enhanced or UV-attenuated polychromatic light in a time-course assay. Photolysis of nonabsorbed14C-2,4-D residues onZ. maysleaves was sensitized by riboflavin regardless of UV light regime, but a larger percentage of nonabsorbed herbicide was degraded under UV-enhanced light compared to UV-attenuated light. Riboflavin was almost completely photolyzed during the first 10 h of exposure; yet, photolysis of14C-2,4-D surface residues in treatments containing riboflavin increased from 59% at 10 h of exposure to 87% at 42 h of exposure. In corresponding treatments without riboflavin, photolysis of14C-2,4-D surface residues was 37% at 10 h of exposure and 84% at 42 h of exposure. In contrast, only 7% of the14C-2,4-D deposited on glass microscope slides was degraded after 42 h of exposure in the absence of riboflavin, whereas 59% was degraded in the presence of riboflavin. Photolysis of 2,4-D onZ. maysleaves in treatments without riboflavin suggests that certain epicuticular component(s) ofZ. maysacted as photosensitizers or catalytic agents that promoted photolysis of nonabsorbed 2,4-D residues.

scholarly journals Botryosphaeriaceae Species Spore-Trapping Studies in California Vineyards

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 717-724 ◽  
Author(s):  
J. R. Úrbez-Torres ◽  
M. Battany ◽  
L. J. Bettiga ◽  
C. Gispert ◽  
G. McGourty ◽  
...  
Keyword(s):  
Strong Relationship ◽  
Early Spring ◽  
Seasonal Abundance ◽  
Petroleum Jelly ◽  
Riverside County ◽  
Spore Release ◽  
Spore Trapping ◽  
Rain Events ◽  
Microscope Slides ◽  
Glass Microscope

The seasonal abundance of Botryosphaeriaceae spp. spores was studied in California vineyards by using glass microscope slides covered with petroleum jelly placed on grapevine cordons and Burkard volumetric spore traps at seven and two different locations, respectively. Correlation analysis was used to determine which meteorological variables (precipitation, relative humidity, temperature, and wind speed) influenced Botryosphaeriaceae spp. spore release. Among all variables, regression analysis resulted in a strong relationship between spore release and precipitation. Additionally, a positive relationship between irrigation and spore release was also observed in the Riverside County vineyard. During the study period, spore discharge of Botryosphaeriaceae spp. occurred from the first fall rain through the last spring rains, coinciding with September to April. However, based on the results obtained from the spore traps, most spores (over 60%) were trapped following rain events during the winter months of December, January, and February, which coincides with the grapevine pruning season. Botryosphaeriaceae spp. spore release was much lower in fall and early spring (22%) and very few or no spores were trapped in late spring and summer (3%). This work suggests that a delay of pruning time in California may be warranted to reduce grapevine infection because the current timing coincides with the greatest period of spore discharge.

scholarly journals A mammary gland whole mount technique that preserves cell fine structure for electron miscroscopy.

1979 ◽  
Vol 27 (9) ◽  
pp. 1271-1274 ◽  
Author(s):  
J M Strum
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Fine Structure ◽  
Mammary Gland ◽  
Trypan Blue ◽  
Negative Image ◽  
Whole Mount ◽  
Microscope Slides ◽  
Glass Microscope ◽  
Unusual Finding

A mammary gland whole mount technique has been developed that preserves cell fine structure and makes it possible to also examine the preparations by electron microscopy. The glands are placed on glass microscope slides, fixed in a paraformaldehyde-glutaraldehyde mixture, defatted in acetone, stained with 0.5% methylene blue (or trypan blue) in saline, and dehydrated in ethanol. They are evaluated and photographed in 100% ethanol. Then specific areas (i.e. containing small growths, tumors, or other lesions) are selected, excised and prepared for electroscopy. The ultrastructural preservation is good, organelles are evident and there is no observable dye precipitate. The only unusual finding is that cell membranes display a "negative" image.

scholarly journals Metrological framework to support accurate, reliable, and reproducible nucleic acid measurements

2021 ◽  
Author(s):  
Mojca Milavec ◽  
Megan H. Cleveland ◽  
Young-Kyung Bae ◽  
Robert I. Wielgosz ◽  
Maxim Vonsky ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Metrology In Chemistry ◽  
Amount Of Substance ◽  
Dna And Rna ◽  
Measurement Results ◽  
Metrological Infrastructure ◽  
Nucleic Acid Analysis ◽  
Primary Focus ◽  
Analysis Working Group ◽  
Measurement Capabilities

Abstract Nucleic acid analysis is used in many areas of life sciences such as medicine, food safety, and environmental monitoring. Accurate, reliable measurements of nucleic acids are crucial for maximum impact, yet users are often unaware of the global metrological infrastructure that exists to support these measurements. In this work, we describe international efforts to improve nucleic acid analysis, with a focus on the Nucleic Acid Analysis Working Group (NAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM). The NAWG is an international group dedicated to improving the global comparability of nucleic acid measurements; its primary focus is to support the development and maintenance of measurement capabilities and the dissemination of measurement services from its members: the National Metrology Institutes (NMIs) and Designated Institutes (DIs). These NMIs and DIs provide DNA and RNA measurement services developed in response to the needs of their stakeholders. The NAWG members have conducted cutting edge work over the last 20 years, demonstrating the ability to support the reliability, comparability, and traceability of nucleic acid measurement results in a variety of sectors.

Functional Viral Metagenomics and the Development of New Enzymes for DNA and RNA Amplification and Sequencing

2011 ◽  
pp. 563-577
Author(s):  
Thomas W. Schoenfeld ◽  
Nick Hermersmann ◽  
Mike Moser ◽  
Darby Renneckar ◽  
Vinay Dhodda ◽  
...  
Keyword(s):  
Viral Metagenomics ◽  
Rna Amplification ◽  
Dna And Rna

scholarly journals A unique mode of nucleic acid immunity performed by a single multifunctional enzyme

2019 ◽  
Author(s):  
S. M. Nayeemul Bari ◽  
Lucy Chou-Zheng ◽  
Katie Cater ◽  
Vidya Sree Dandu ◽  
Alexander Thomas ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Genetic Material ◽  
Dual Function ◽  
Bacterial Phyla ◽  
Dna And Rna ◽  
Multiple Components ◽  
Unique Mode ◽  
Phage Dna ◽  
Domains Of Life ◽  
Replication Intermediates

Organisms spanning all domains of life protect against pathogens using diverse mechanisms of nucleic acid immunity which detect and eliminate foreign genetic material1. The perpetual arms race between bacteria and their viruses (phages) has given rise to both innate and adaptive nucleic acid immunity mechanisms, including restriction-modification and CRISPR-Cas, respectively2. These sophisticated systems encode multiple components that sense and degrade phage-derived genetic material while leaving the host genome unharmed. Here, we describe a unique mode of innate immunity performed by a single protein, SERP2475, herein renamed to Nhi. We show that this enzyme protects against phages by preventing phage DNA accumulation, and in a purified system it degrades both DNA and RNA substrates. This enzyme also exhibits ATP-dependent helicase activity, and excess ATP abrogates nuclease function, suggesting a possible mechanism for its regulation. Further, using directed evolution, we isolated and characterized a collection of resistant phage mutants and found that a single-stranded DNA binding protein provides a natural means for phages to escape immunity. These observations support a model in which Nhi senses and degrades phage-specific replication intermediates. We also found that this dual-function enzyme protects against diverse phages, and its homologs are distributed across several bacterial phyla. Altogether, our findings reveal a new innate immune system with minimal composition that provides robust defense against diverse bacterial viruses.

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