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Christopher W. Simmons - One of the best experts on this subject based on the ideXlab platform.
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Rapid, in situ detection of Agrobacterium tumefaciens attachment to Leaf Tissue
Biotechnology progress, 2012Co-Authors: Christopher W. Simmons, N. Nitin, Jean S. VandergheynstAbstract:Attachment of the plant pathogen Agrobacterium tumefaciens to host plant cells is an early and necessary step in plant transformation and agroinfiltration processes. However, bacterial attachment behavior is not well understood in complex plant Tissues. Here we developed an imaging-based method to observe and quantify A. tumefaciens attached to Leaf Tissue in situ. Fluorescent labeling of bacteria with nucleic acid, protein, and vital dyes was investigated as a rapid alternative to generating recombinant strains expressing fluorescent proteins. Syto 16 green fluorescent nucleic acid stain was found to yield the greatest signal intensity in stained bacteria without affecting viability or infectivity. Stained bacteria retained the stain and were detectable over 72 h. To demonstrate in situ detection of attached bacteria, confocal fluorescent microscopy was used to image A. tumefaciens in sections of lettuce Leaf Tissue following vacuum-infiltration with labeled bacteria. Bacterial signals were associated with plant cell surfaces, suggesting detection of bacteria attached to plant cells. Bacterial attachment to specific Leaf Tissues was in agreement with known Leaf Tissue competencies for transformation with Agrobacterium. Levels of bacteria attached to Leaf cells were quantified over time post-infiltration. Signals from stained bacteria were stable over the first 24 h following infiltration but decreased in intensity as bacteria multiplied in planta. Nucleic acid staining of A. tumefaciens followed by confocal microscopy of infected Leaf Tissue offers a rapid, in situ method for evaluating attachment of A. tumefaciens' to plant expression hosts and a tool to facilitate management of transient expression processes via agroinfiltration. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
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A model of Agrobacterium tumefaciens vacuum infiltration into harvested Leaf Tissue and subsequent in planta transgene transient expression
Biotechnology and Bioengineering, 2009Co-Authors: Christopher W. Simmons, Jean S. Vandergheynst, Shrinivasa K. UpadhyayaAbstract:Agrobacterium-mediated gene transfer, or agroinfiltration, can be a highly efficient method for transforming and inducing transient transgene expression in plant Tissue. The technique uses the innate DNA secretion pathway of Agrobacterium tumefaciens to vector a particular plasmid-encoded segment of DNA from the bacteria to plant cells. Vacuum is often applied to plant Tissue submerged in a suspension of A. tumefaciens to improve agroinfiltration. However, the effects of vacuum application on agroinfiltration and in planta transient transgene expression have not been well quantified. Here we show that vacuum application and release act to drive A. tumefaciens suspension into the interior of Leaf Tissue. Moreover, the amount of suspension that enters leaves can be predicted based on the vacuum intensity and duration. Furthermore, we show that transient expression levels of an agroinfiltrated reporter gene vary in response to the amount of A. tumefaciens vacuum infiltrated into Leaf Tissue, suggesting that vacuum infiltration conditions can be tailored to achieve optimal transient transgene expression levels after agroinfiltration. Biotechnol. Bioeng. 2009; 102: 965–970. © 2008 Wiley Periodicals, Inc.
Jean S. Vandergheynst - One of the best experts on this subject based on the ideXlab platform.
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Rapid, in situ detection of Agrobacterium tumefaciens attachment to Leaf Tissue
Biotechnology progress, 2012Co-Authors: Christopher W. Simmons, N. Nitin, Jean S. VandergheynstAbstract:Attachment of the plant pathogen Agrobacterium tumefaciens to host plant cells is an early and necessary step in plant transformation and agroinfiltration processes. However, bacterial attachment behavior is not well understood in complex plant Tissues. Here we developed an imaging-based method to observe and quantify A. tumefaciens attached to Leaf Tissue in situ. Fluorescent labeling of bacteria with nucleic acid, protein, and vital dyes was investigated as a rapid alternative to generating recombinant strains expressing fluorescent proteins. Syto 16 green fluorescent nucleic acid stain was found to yield the greatest signal intensity in stained bacteria without affecting viability or infectivity. Stained bacteria retained the stain and were detectable over 72 h. To demonstrate in situ detection of attached bacteria, confocal fluorescent microscopy was used to image A. tumefaciens in sections of lettuce Leaf Tissue following vacuum-infiltration with labeled bacteria. Bacterial signals were associated with plant cell surfaces, suggesting detection of bacteria attached to plant cells. Bacterial attachment to specific Leaf Tissues was in agreement with known Leaf Tissue competencies for transformation with Agrobacterium. Levels of bacteria attached to Leaf cells were quantified over time post-infiltration. Signals from stained bacteria were stable over the first 24 h following infiltration but decreased in intensity as bacteria multiplied in planta. Nucleic acid staining of A. tumefaciens followed by confocal microscopy of infected Leaf Tissue offers a rapid, in situ method for evaluating attachment of A. tumefaciens' to plant expression hosts and a tool to facilitate management of transient expression processes via agroinfiltration. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
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A model of Agrobacterium tumefaciens vacuum infiltration into harvested Leaf Tissue and subsequent in planta transgene transient expression
Biotechnology and Bioengineering, 2009Co-Authors: Christopher W. Simmons, Jean S. Vandergheynst, Shrinivasa K. UpadhyayaAbstract:Agrobacterium-mediated gene transfer, or agroinfiltration, can be a highly efficient method for transforming and inducing transient transgene expression in plant Tissue. The technique uses the innate DNA secretion pathway of Agrobacterium tumefaciens to vector a particular plasmid-encoded segment of DNA from the bacteria to plant cells. Vacuum is often applied to plant Tissue submerged in a suspension of A. tumefaciens to improve agroinfiltration. However, the effects of vacuum application on agroinfiltration and in planta transient transgene expression have not been well quantified. Here we show that vacuum application and release act to drive A. tumefaciens suspension into the interior of Leaf Tissue. Moreover, the amount of suspension that enters leaves can be predicted based on the vacuum intensity and duration. Furthermore, we show that transient expression levels of an agroinfiltrated reporter gene vary in response to the amount of A. tumefaciens vacuum infiltrated into Leaf Tissue, suggesting that vacuum infiltration conditions can be tailored to achieve optimal transient transgene expression levels after agroinfiltration. Biotechnol. Bioeng. 2009; 102: 965–970. © 2008 Wiley Periodicals, Inc.
Shrinivasa K. Upadhyaya - One of the best experts on this subject based on the ideXlab platform.
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A model of Agrobacterium tumefaciens vacuum infiltration into harvested Leaf Tissue and subsequent in planta transgene transient expression
Biotechnology and Bioengineering, 2009Co-Authors: Christopher W. Simmons, Jean S. Vandergheynst, Shrinivasa K. UpadhyayaAbstract:Agrobacterium-mediated gene transfer, or agroinfiltration, can be a highly efficient method for transforming and inducing transient transgene expression in plant Tissue. The technique uses the innate DNA secretion pathway of Agrobacterium tumefaciens to vector a particular plasmid-encoded segment of DNA from the bacteria to plant cells. Vacuum is often applied to plant Tissue submerged in a suspension of A. tumefaciens to improve agroinfiltration. However, the effects of vacuum application on agroinfiltration and in planta transient transgene expression have not been well quantified. Here we show that vacuum application and release act to drive A. tumefaciens suspension into the interior of Leaf Tissue. Moreover, the amount of suspension that enters leaves can be predicted based on the vacuum intensity and duration. Furthermore, we show that transient expression levels of an agroinfiltrated reporter gene vary in response to the amount of A. tumefaciens vacuum infiltrated into Leaf Tissue, suggesting that vacuum infiltration conditions can be tailored to achieve optimal transient transgene expression levels after agroinfiltration. Biotechnol. Bioeng. 2009; 102: 965–970. © 2008 Wiley Periodicals, Inc.
Mikal E. Saltveit - One of the best experts on this subject based on the ideXlab platform.
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wound induced phenolic accumulation and browning in lettuce lactuca sativa l Leaf Tissue is reduced by exposure to n alcohols
Postharvest Biology and Technology, 2005Co-Authors: Young Jun Choi, Francisco A Tomasbarberan, Mikal E. SaltveitAbstract:A wound signal originates at the site of injury in lettuce ( Lactuca sativa L.) Leaf Tissue and propagates into adjacent Tissue where it induces a number of physiological responses which include increased phenolic metabolism with the de novo synthesis of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), the synthesis and accumulation of soluble phenolic compounds (e.g., chlorogenic acid), and subsequent Tissue browning. Exposing excised mid-rib Leaf Tissue to vapors (20 mol/(g FW)) or aqueous solutions (100 mM) of n-alcohols inhibited this wound-induced Tissue browning by 40 and 60%, respectively. Effectiveness of the alcohol increased linearly from ethanol to the 7-carbon heptanol, and then was lost for the longer n-alcohols 1-octanol and 1-nonanol. The 2- and 3-isomers of the effective alcohols did not significantly reduce wound-induced phenolic accumulation at optimal 1-alcohol concentrations, but significant reductions did occur at much higher concentrations (100 mol/(g FW)) of the 2-, and 3-isomers. The active n-alcohols were maximally effective when applied during the first 2 h after excision, and were ineffective if applied 6 h after excision. Phospholipase D (PLD) and its products linolenic acid (LA) and phosphatidic acid (PA) are thought to initiate the oxylipin pathway that culminates in the production of jasmonic acid, and PLD is specifically inhibited by 1-butanol, but not by 2-, or 3-butanol. These results suggest that PLD, LA, PA, and the oxylipin pathway may be involved in producing the wound signal responsible for increased wound-induced PAL activity, phenolic accumulation and browning in fresh-cut lettuce Leaf Tissue. © 2005 Elsevier B.V. All rights reserved.
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Antioxidant capacity of lettuce Leaf Tissue increases after wounding.
Journal of agricultural and food chemistry, 2002Co-Authors: Ho-min Kang, Mikal E. SaltveitAbstract:Wounding induced the accumulation of phenolic compounds in Iceberg and Romaine lettuce Leaf Tissue. Phenolic concentrations were quantified after holding the Leaf Tissue at 10 degrees C for 48 h as the absorbance of a methanol extract at 320 nm, and by the Folin-Ciocalteu method. Heat-shock treatments applied by immersing Tissue in 45 degrees C water for 2.5 min before or after wounding reduced the accumulation of phenolic compounds. Compared to the nonwounded, nonheat-shocked controls, these and other wounding and heat-shock treatments produced Leaf Tissue with a 4-fold range in phenolic content. The antioxidant capacity of the Tissue, measured as DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl)-radical scavenging activity, or as ferric-reducing antioxidant power (FRAP), increased after wounding. The increase was linearly correlated with the increase in phenolic compounds in Iceberg (R(2) > 0.97) and in Romaine (R(2) > 0.95) lettuce Leaf Tissue. Increased consumption of diets rich in phenolic antioxidants may contribute to reducing human diseases. Treatments that reduce the browning of wounded lettuce Leaf Tissue by preventing the oxidation of the accumulated wound-induced phenolic compounds may produce a healthier fresh-cut product than treatments that prevent the wound-induced synthesis and accumulation of phenolic compounds with antioxidant properties.
Savitree Limtong - One of the best experts on this subject based on the ideXlab platform.
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endophytic yeast diversity in Leaf Tissue of rice corn and sugarcane cultivated in thailand assessed by a culture dependent approach
Fungal Biology, 2018Co-Authors: Pannida Khunnamwong, Sasitorn Jindamorakot, Savitree LimtongAbstract:Endophytic yeasts are yeast that can colonize healthy plant Tissues without causing any damage to the host plant. This work aimed to explore the diversity of endophytic yeasts in Leaf Tissue of main agricultural crops (rice, corn and sugarcane) in Thailand, by a culture-dependent approach. A total of 311 Leaf samples, consisting of rice (n = 100), corn (n = 109) and sugarcane (n = 102). From the Tissue of rice (n = 92), corn (n = 76) and sugarcane (n = 78) Leaf samples, 117, 118 and 123 yeast strains were respectively isolated and identified based on the D1/D2 region of the large subunit (LSU) rRNA gene sequence analysis to be yeast species in both the phyla Basidiomycota and Ascomycota. Higher numbers of basidiomycetous yeast than ascomycetous yeast were detected in the Leaf Tissue of the three crops. Pseudozyma (Dirkmeia) churashimaensis (Ustilaginales) was the most prevalent yeast species in the rice and corn leaves with relative frequencies (RF) of 35.9 % and 17.8 %, respectively. Whereas the predominant species in the sugarcane leaves was Meyerozyma caribbica (Saccharomycetales) with an RF of 14.6 %. In addition, six new yeast species and one new yeast genus were proposed. Our findings suggest that these plant species are good sources from which new yeast species may be isolated.