scholarly journals Azorhizobium caulinodans ORS571 Colonizes the Xylem of Arabidopsis thaliana

2001 ◽  
Vol 14 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Philip J. Stone ◽  
Kenneth J. O'Callaghan ◽  
Michael R. Davey ◽  
Edward C. Cocking

Improved conditions were used for the aseptic growth of Arabidopsis thaliana to investigate whether xylem colonization of A. thaliana by Azorhizobium caulinodans ORS571 might occur. When seedlings were inoculated with ORS571 (pXLGD4) tagged with the lacZ reporter gene, nearly all of the plants showed blue regions of ORS571 colonization at lateral root cracks (LRC). The flavonoids naringenin and liquiritigenin significantly stimulated colonization of LRC by ORS571. Blue bands of ORS571 (pXLGD4) bacteria were observed histochemically in the xylem of intact roots of inoculated plants. Detailed microscopic analysis of sections of primary and lateral roots from inoculated A. thaliana confirmed xylem colonization. Xylem colonization also occurred with an ORS571 nodC mutant deficient in nodulation factors. There was no significant difference in the percentage of plants with xylem colonization or in the mean length of xylem colonized per plant between plants inoculated with either ORS571 (pXLGD4) or ORS571::nodC (pXLGD4), with or without naringenin.

1997 ◽  
Vol 10 (5) ◽  
pp. 560-570 ◽  
Author(s):  
Clare Gough ◽  
Christine Galera ◽  
Jacques Vasse ◽  
Gordon Webster ◽  
Edward C. Cocking ◽  
...  

The ability of Azorhizobium caulinodans ORS571 and other diazotrophic bacteria to internally colonize roots of Arabidopsis thaliana has been studied. Strains tagged with lacZ or gusA reporter genes were used, and the principal colonization sites were found to be the points of emergence of lateral roots, lateral root cracks (LRCs). High frequencies of colonization were found; 63 to 100% of plants were colonized by ORS571, and 100% of plants were colonized by Herbaspirillum seropedicae. After LRCs were colonized, bacteria moved into intercellular spaces between the cortical and endodermal cell layers. Specific flavonoids, naringenin and daidzein, at 5 × 10-5 M, significantly promoted colonization by ORS571. By using a nodC and a nodD mutant of ORS571, it was shown that neither Nod factors nor NodD are involved in colonization or flavonoid stimulation of colonization. Flavonoids did not appear to be stimulating LRC colonization by their activity as nutritional factors. LRC and intercellular colonization by H. seropedicae was stimulated by naringenin and daidzein at the same concentration that stimulated colonization by ORS571.


Author(s):  
Giovani Orlando Cancino Escalante ◽  
S E Cancino ◽  
Enrique Quevedo Garcia

Root systems of two Andean blackberry materials (thorn and thornless) of Rubus glaucus Benth cultured in vitro in the presence of five treatments (four flavonoids and one control) were inoculated with Azorhizobium caulinodans ORS571 (pXLGD4)  (a strain carrying the lacZ reporter gene which facilitated the detection of bacterial colonization). Evaluation of colonization effectiveness for each treatment was done by means of application of experimental design measuring frequency and intensity parameters. Statistical analysis showed differences at comparing flavonoids vs. control and the overall higher effectiveness of the flavonoid naringenin. Observation of colonization was made by light and electron microscope confirming internal colonization of Andean blackberry roots by A. caulinodans. This is the first work demonstrating root colonization of R.glaucus by azorhizobia and therefore settling the basis for future investigations and scientific applications related to interaction with plant growth-promoting bacteria under the effect of flavonoids, along with possible implications of common benefit for non-legume crops in the northwest region of Colombia.  Key Words: Azorhizobium caulinodans ORS571, Andean blackberry, flavonoids, LacZ, lateral roots, naringenin. 


2011 ◽  
Vol 22 (6) ◽  
pp. 455-459 ◽  
Author(s):  
Ronaldo Araújo Souza ◽  
Yara T. Corrêa Silva Sousa ◽  
José Antônio Poli de Figueiredo ◽  
João Da Costa Pinto Dantas ◽  
Suely Colombo ◽  
...  

Considering that instrumentation of the apical foramen has been suggested for root canal infection control, this study analyzed the relationship between the files that bind at the apical foramen and the foraminal openings in 50 maxillary central incisors. After preparation of the pulp chamber, access to the canal was obtained with #1 and 2 LA Axxess and K-files with tip cut were inserted up to the apical foramen until binding was felt. The files were fixed with methyl cyanoacrylate and the tooth-file sets were cross-sectioned 10 mm short of the apex. Scanning electron microscopic analysis was carried out and files and foraminal areas were measured using Image Tool software. Statistically significant difference (p<0.0001) was found between files and the apical foraminal areas. The mean foraminal area was 3.8 times larger than the mean file area. The results of this study suggest that it would require 4 files of greater size beyond the one that bound to the foramen in order to allow a better relationship between files and apical openings of maxillary central incisors.


2014 ◽  
Vol 57 (5) ◽  
pp. 274-281 ◽  
Author(s):  
Eun Kyung Yoon ◽  
Ju-Won Kim ◽  
Ji Hyun Yang ◽  
Soo-Hwan Kim ◽  
Jun Lim ◽  
...  

1970 ◽  
Vol 13 (4) ◽  
pp. 715-724 ◽  
Author(s):  
Richard L. Powell ◽  
Oscar Tosi

Vowels were segmented into 15 different temporal segments taken from the middle of the vowel and ranging from 4 to 60 msecs, then presented to 6 subjects with normal hearing. The mean temporal-segment recognition threshold of 15 msecs with a range from 9.3 msecs for the /u/ to 27.2 milliseconds for the /a/. Misidenti-fication of vowels was most often confused with the vowel sound adjacent to it on the vowel-hump diagram. There was no significant difference between the cardinal and noncardinal vowels.


1991 ◽  
Vol 30 (05) ◽  
pp. 183-188
Author(s):  
A. Aydrner ◽  
A. Oto ◽  
E. Oram ◽  
O. Gedik ◽  
C. F. Bekdik ◽  
...  

Left ventricular function including regional wall motion (RWM) was evaluated by 99mTc first-pass and equilibrium gated blood pool ventriculography and glycohemoglobin (HbA1c) blood levels determined by a quantitative column technique in 25 young patients with insulin-dependent diabetes mellitus without clinical evidence of heart disease, and in healthy controls matched for age and sex. Phase analysis revealed abnormal RWM in 19 of 21 diabetic patients. The mean left ventricular global ejection fraction, the mean regional ejection fraction and the mean 1/3 filling fraction were lower and the time to peak ejection, the time to peak filling and the time to peak ejection /cardiac cycle were longer in diabetics than in controls. We found high HbA1c levels in all diabetics. There was no significant difference between patients with and without retinopathy and with and without peripheral neuropathy in terms of left ventricular function and HbA1c levels.


1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.


1993 ◽  
Vol 69 (01) ◽  
pp. 035-040 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina

SummaryFour thromboplastin reagents were tested by 18 laboratories in Europe, North-America, and Australasia, according to a detailed protocol. One thromboplastin was the International Reference Preparation for ox brain thromboplastin combined with adsorbed bovine plasma (coded OBT/79), and the second was a certified reference material for rabbit brain thromboplastin, plain (coded CRM 149R). The other two thromboplastin reagents were another rabbit plain brain thromboplastin (RP) with a lower ISI than CRM 149R and a rabbit brain thromboplastin combined with adsorbed bovine plasma (RC). Calibration of the latter two reagents was performed according to methods recommended by the World Health Organization (W. H. O.).The purpose of this study was to answer the following questions: 1) Is the calibration of the RC reagent more precise against the bovine/combined (OBT/79) than against the rabbit/plain reagent (CRM 149R)? 2) Is the precision of calibration influenced by the magnitude of the International Sensitivity Index (ISI)?The lowest inter-laboratory variation of ISI was observed in the calibration of the rabbit/plain reagent (RP) against the other rabbit/plain reagent (CRM 149R) (CV 1.6%). The highest interlaboratory variation was obtained in the calibration of rabbit/plain (RP) against bovine/combined (OBT/79) (CV 5.1%). In the calibration of the rabbit/combined (RC) reagent, there was no difference in precision between OBT/79 (CV 4.3%) and CRM 149R (CV 4.2%). Furthermore, there was no significant difference in the precision of the ISI of RC obtained with CRM 149R (ISI = 1.343) and the rabbit/plain (RP) reagent with ISI = 1.14. In conclusion, the calibration of RC could be performed with similar precision with either OBT/79 or CRM 149R, or RP.The mean ISI values calculated with OBT/79 and CRM 149R were practically identical, indicating that there is no bias in the ISI of these reference preparations and that these reference preparations have been stable since their original calibration studies in 1979 and 1987, respectively.International Normalized Ratio (INR) equivalents were calculated for a lyophilized control plasma derived from patients treated with oral anticoagulants. There were small but significant differences in the mean INR equivalents between the bovine and rabbit thromboplastins. There were no differences in the interlaboratory variation of the INR equivalents, when the four thromboplastins were compared.


2020 ◽  
Vol 3 (1) ◽  
pp. ACCEPTED
Author(s):  
Rho-Jeong Rae

This study investigated the boreal digging frog, Kaloula borealis, to determine the egg hatching period and whether the hatching period is affected by incubation temperature. The results of this study showed that all the eggs hatched within 48 h after spawning, with 28.1% (±10.8, n=52) hatching within 24 h and 99.9% (±0.23, n=49) within 48 h after spawning. A significant difference was noted in the mean hatching proportion of tadpoles at different water temperatures. The mean hatching rates between 15 and 24 h after spawning was higher at a water temperature of 21.1 (±0.2) °C than at 24.1 (±0.2) °C. These results suggest that incubation temperature affected the early life stages of the boreal digging frog, since they spawn in ponds or puddles that form during the rainy season.


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