Epiphytic populations of Pseudomonas syringae on barley

1992 ◽  
Vol 38 (2) ◽  
pp. 111-114 ◽  
Author(s):  
Dimitrios G. Georgakopoulos ◽  
David C. Sands
Keyword(s):  
Key Words ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
The Other ◽  
Population Increase ◽  
Leaf Sample ◽  
Leaf Stage ◽  
Colony Forming Units ◽  
Active Bacteria ◽  
Population Counts

The epiphytic populations of Pseudomonas syringae were monitored on 23 barley entries planted in the field in four replications during the summer of 1986, and on six selected entries during the summer of 1987, from the second-leaf stage until senescence. Populations were initially low (0–3 log colony-forming units (cfu) per leaf) in all but one entry; they generally increased throughout the season, and at the end they reached 3–7 log cfu/leaf. Significant differences among the average epiphytic populations were found in the 1986 trial; only one entry, however, had a significantly different average population in the 1987 trial. The slopes of population increase were also compared: significant differences were observed in 1986 but not in 1987. In addition to epiphytic population counts, the percentage of ice nucleation active bacteria was determined in the population isolated from each leaf sample, and averaged throughout the season for each entry. Significant differences were observed in 1986 and in 1987. When the entries were ranked according to their average epiphytic population and compared between the two experiments, they were found to be very similar. The same was not true for the other parameters studied in the experiment. Key words: epiphytic populations, ice nucleation, barley.

scholarly journals Ice-nucleation-active (INA) Bacteria: A Detriment to Strawberry Flower Survival during Low-temperature Exposure

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 428B-428
Author(s):  
Michele R. Warmund ◽  
James T. English
Keyword(s):  
Low Temperature ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Ice Crystals ◽  
Colony Forming Units ◽  
Ina Bacteria ◽  
Temperature Exposure ◽  
Low Temperature Exposure ◽  
Ice Crystallization

Experiments were conducted to determine the temperatures at which different densities of INA bacteria incite ice crystallization on `Totem' strawberry flowers and to determine if there is a relationship between densities of INA bacteria on strawberry flowers and floral injury. Primary flowers were inoculated with Pseudomonas syringae at 106 cells/ml buffer, incubated at 25°C day/10°C night and 100% RH for 48 h, and exposed to –2.0°C. No ice nucleation occurred on these inoculated flowers and all of the flowers survived. However, when inoculated flowers were subjected to lower temperatures, ice nucleation occurred at –2.2°C and few of the flowers survived. In contrast, ice crystals formed on the surface of most non-inoculated flowers at –2.8°C and 21% of the flowers survived exposure to –3.5°C. When INA bacterial densities were ≈105 colony forming units/g dry wt, floral injury occurred at a warmer temperature than to flowers that had lower bacterial densities.

scholarly journals Ice Nucleation and Propagation in Cranberry Uprights and Fruit Using Infrared Video Thermography

1999 ◽  
Vol 124 (6) ◽  
pp. 619-625 ◽  
Author(s):  
Beth Ann A. Workmaster ◽  
Jiwan P. Palta ◽  
Michael Wisniewski
Keyword(s):  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Vaccinium Macrocarpon ◽  
Plant Surface ◽  
Nucleation Event ◽  
Abaxial Surface ◽  
Ripe Fruit ◽  
Initiation And Propagation ◽  
Infrared Video ◽  
Active Bacteria

Infrared video thermography was used to study formation of ice in leaves, stems, and fruit of cranberry (Vaccinium macrocarpon Ait. `Stevens'). Ice formed on the plant surface at -1 or -2 °C by freezing of a droplet of water containing ice nucleation-active bacteria (Pseudomonas syringae van Hall). Samples were then cooled to a minimum of -8 °C. Observations on the initiation and propagation of ice were recorded. Leaves froze only when ice was present on the abaxial surface. Once initiated, ice propagated to the stem and then readily to other leaves. In both unripe and ripe fruit, ice propagation from the stem to the fruit via the pedicel was not observed. Fruit remained supercooled for up to 1 hour after ice was present in the stem. Fruit could only be nucleated when ice was present at the calyx (distal) end. Red (ripe) berries supercooled to colder temperatures and for longer durations than blush (unripe) berries before an apparent intrinsic nucleation event occurred. These observations provide evidence that leaves are nucleated by ice penetration via stomata. The ability of fruit to supercool appears to be related to the presence of barriers to extrinsic ice propagation at both the pedicel and fruit surface. Stomata at the calyx end of the fruit in the remnant nectary area may provide avenues for extrinsic ice nucleation.

Addition of ice-nucleation active bacteria: Pseudomonas syringae pv. panici on freezing of solid model food

LWT ◽  
2010 ◽  
Vol 43 (9) ◽  
pp. 1414-1418 ◽  
Author(s):  
Shaozhi Zhang ◽  
Haiying Wang ◽  
Guangming Chen
Keyword(s):  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Solid Model ◽  
Model Food ◽  
Active Bacteria

scholarly journals 557 PB 374 EFFICACIES OF CRYOPROTECTANTS APPLIED TO STRAWBERRY PLANTS INOCULATED WITH ICE-NUCLEATION-ACTIVE BACTERIA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 511d-511
Author(s):  
Michele R. Warmund ◽  
James T. English
Keyword(s):  
Low Temperature ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Freezing Injury ◽  
Fragaria Ananassa ◽  
Full Bloom ◽  
Ina Bacteria ◽  
Active Bacteria ◽  
Temperature Exposure ◽  
Low Temperature Exposure

Cryoprotectants were applied at labeled rates to primary flowers of `Honeoye' strawberry (Fragaria × ananassa Duch.) plants at full bloom to determine their effects on the floral organs. Frostgard at 50 ml/liter or KDL at 22 ml/liter injured pistils and resulted in misshapened fruit. Floral buds that were closed when cryoprotectants were applied were uninjured. In other experiments, efficacies of cryoprotectants were determined after floral tissues of `Honeoye' strawberry plants were inoculated or not inoculated with the ice-nucleation-active (INA) bacteria, Pseudomonas syringae van Hall and subjected to sub-freezing temperatures. None of the products protected primary or secondary flowers against freezing injury regardless of the occurrence of INA bacteria. INA bacteria were not recovered from primary flowers of treated plants that were killed by low temperature exposure, indicating that non-bacterial nuclei may incite freezing in these tissues.

scholarly journals A Study of Ice Nucleation and Propagation in Cranberry Plant using Infrared Video Thermography

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 448B-448
Author(s):  
Beth Ann A. Workmaster ◽  
Michael Wisniewski ◽  
Jiwan P. Palta
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Surface ◽  
Ice Nucleation ◽  
Vaccinium Macrocarpon ◽  
Tissue Temperature ◽  
Lower Leaf Surface ◽  
Nucleation Barrier ◽  
Infrared Video ◽  
Active Bacteria ◽  
Surface Ice

Infrared video thermography has recently been used to visualize ice nucleation and propagation in plants. At the UW–Madison Biotron facility, we studied the formation of ice in various parts of fruit-bearing cranberry (Vaccinium macrocarpon Ait.) uprights. The fruits were at the blush to red stages of ripening. Samples were nucleated at –1 or –2°C with ice-nucleating-active bacteria (Pseudomonas syringae). Following nucleation, samples were cooled to –6°C in ≈1 hour. The following observations were made: 1) When nucleated at a cut end, ice propagated rapidly throughout the stem and into the leaves at a tissue temperature of about –4°C. However, ice did not propagate from the stem through the pedicel to reach the fruit. During the 1 hour after ice propagation in the stem, the fruit remained supercooled. 2) Within the duration of the experiment, leaves could not be nucleated from the upper surface. Ice from the lower leaf surface did nucleate the leaf, and ice propagated from the leaf to the stem and other leaves readily. 3) Both red and blush berries could only be nucleated at the calyx end of the fruit. 4) Red berries supercooled to colder temperatures and for longer durations than the blush berries. 5) In support of our previous studies, red berries were able to tolerate some ice in their tissue. These observations suggest that: 1) The upper leaf surface and the fruit surface (other than the calyx end) are barriers to ice propagation in the cranberry plant; and 2) at later stages of fruit ripening the pedicel becomes an ice nucleation barrier from the stem to the fruit. This may contribute to the ability of the cranberry fruit to supercool.

scholarly journals Characterization of Wheat Genotypes as Sources of Ice Nucleation Active Bacteria for Bioprecipitation Aerosols

2015 ◽  
Vol 4 (2) ◽  
pp. 63-72
Author(s):  
Abd-Alrahman Moukahel ◽  
Siham Asaad ◽  
Bakri Debbes ◽  
Cindy E. Morris ◽  
David C. Sands
Keyword(s):  
Pseudomonas Syringae ◽  
Agricultural Research ◽  
Leaf Tissue ◽  
Seed Storage ◽  
Ice Nucleation ◽  
Potential Conflict ◽  
Dry Land ◽  
Breeding Lines ◽  
Wheat Genotypes ◽  
Active Bacteria

As water resources become more and more scarce, production of crops under dry land conditions brings agriculture into potential conflict with other uses of water. There is an emerging awareness that the orientation of the goals of plant breeding can be shifted to create crops that can offset the negative impacts of agriculture on the environment in order to make agriculture more sustainable. Here we have explored the possibility to select lines of wheat, the crop that occupies more land than any individual crop, that contribute to the bioprecipitation cycle. In this cycle the ice nucleation (IN) active component of the microflora on leaves contributes to the ice nuclei in the atmosphere that activate processes in clouds necessary for rainfall. In line with this long term goal, we have deter-mined the capacity of breeding lines of wheat, adapted to dry land conditions, to harbor IN active bacteria.  In particular, we focused on Pseudomonas syringae, the most ubiquitous of the IN active bacteria on plants.  Because strains of this bacterium can be a plant pathogen, we evaluated the abundance of non-pathogenic IN active strains of P. syringae on a range of wheat genotypes from the research program of the International Center for Agricultural Research in the Dry Areas. Of the 25 genotypes of bread wheat examined, leaves of 12 genotypes naturally harbored P. syringae in the field.  Eight of these genotypes harbored populations of IN active P. syringae with an impaired Type 3 Secretion System (involved in pathogenicity) as high as 4 x 105 105 CFU g-1 of leaf tissue. Three of these 8 wheat genotypes harbored IN active P. syringae that were not virulent on either bread or durum wheat and for 1 of these wheat genotypes the strains of IN active P. syringae were virulent on only 1 of the 13 plant species on which pathogenicity was tested. For the wheat geno-types that had P. syringae on leaves in the field, bacteria were naturally transmitted to seed but dur-ing seed storage the bacterium could be detected on only half of the genotypes after 3 months of storage. To explore the possibility of enhancing the IN active microflora on leaves, we assessed the capacity of bacteria inoculated on seed to be transmitted to seed.  The effectiveness of the trans-mission depended on an interaction of wheat genotype and bacterial strain. Overall, this work points to the possibility of selecting plants with the goal of changing their microflora for purposes other than resistance to plant disease and in this case for the purpose of contributing to processes that could favor rainfall.

HISTOPATHOLOGY OF THE PIGMENTED TUMORAL-LIKE LESIONS OF THE SKIN AT HUE HOSPITAL OF MEDICINE AND PHARMACY UNIVERSITY

2018 ◽  
Vol 8 (4) ◽  
pp. 65-69
Author(s):  
Mao Nguyen Van ◽  
Dong Tran Nam
Keyword(s):  
Key Words ◽  
Definitive Diagnosis ◽  
The Other ◽  
Cell Tumour ◽  
Cross Sectional ◽  
Skin Tumour ◽  
Clinical Appearance ◽  
The Face ◽  
The Common ◽  
Difficult Cases

Background: Pigmented tumour of the skin is one of the common tumour in human including the benign pigmented tumours (more common) called Nevi tumours and the malignant one called melanoma which was less frequent but the most poor in prognosis. In addition, the others not belonging to these group had the same clinical appearance, so the application of histopathology and immunohistochemistry for the definitive diagnosis was indespensible. Objectives: 1. To describe the macroscopic features of the pigmented tumoral-like lesions; 2. To classify the histopathologic types of the pigmented cell tumours and the other pigmented tumours of the skin. Materials and Method: Cross-sectional research on 55 patients diagnosed as pigmented tumoral lesions by clinician, then all definitively diagnosed by histopathology combining the immunohistochemistry in difficult cases. Results: There was no difference in gender, the disease was discovered most common in adult, especially with the age over 51 years old (58.1%). the most region located was in the face accounting for 60%, following the trunk and limbs (14.6%, 12.8% respectively). All 3 malignant melanomas happened in foot. The most common color of the lesions was black (65.4%), the other ones were rose, grey and blue. Histopathology and immunohisthochemistry showed that the true pigmented cell tumours were 52.6% encompassing benign ones (Nevi tumour) (41.8%), melanoma (5.4%) and lentigo (5.4%). 47.4% was not the true pigmented cell tumour including pigmented basocellular carcinoma (36.4%) and the others less common as histiofibromas, acanthoma and papilloma. Conclusion: the pigmented tumoral-like lesions of the skin could be the true pigmented cell tumours and the others, so the application of the histopathology and the immunohistochemistry after the clinical discovery helps to determine and classify the disease definitely and for the best orientation of treatment as well. Key words: skin tumour, benign pigmented tumour (Nevi), malignant pigmented tumour (melanoma), pigmented basocellular carcinoma

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