scholarly journals In vivo Conformation of Mitochondrial DNA Revealed by Pulsed-Field Gel Electrophoresis in the True Slime Mold, Physarum polycephalum

DNA Research ◽  
2000 ◽  
Vol 7 (2) ◽  
pp. 83-91 ◽  
Author(s):  
R. Sakurai ◽  
N. Sasaki ◽  
H. Takano ◽  
T. Abe ◽  
S. Kawano
2000 ◽  
Vol 38 (5) ◽  
pp. 1931-1939 ◽  
Author(s):  
Ruth Zadoks ◽  
Willem van Leeuwen ◽  
Herman Barkema ◽  
Otlis Sampimon ◽  
Henri Verbrugh ◽  
...  

Thirty-eight bovine mammary Staphylococcus aureusisolates from diverse clinical, temporal, and geographical origins were genotyped by pulsed-field gel electrophoresis (PFGE) afterSmaI digestion of prokaryotic DNA and by means of binary typing using 15 strain-specific DNA probes. Seven pulsed-field types and four subtypes were identified, as were 16 binary types. Concordant delineation of genetic relatedness was documented by both techniques, yet based on practical and epidemiological considerations, binary typing was the preferable method. Genotypes of bovine isolates were compared to 55 previously characterized human S. aureusisolates through cluster analysis of binary types. Genetic clusters containing strains of both human and bovine origin were found, but bacterial genotypes were predominantly associated with a single host species. Binary typing proved an excellent tool for comparison ofS. aureus strains, including methicillin-resistant S. aureus, derived from different host species and from different databases. For 28 bovine S. aureus isolates, detailed clinical observations in vivo were compared to strain typing results in vitro. Associations were found between distinct genotypes and severity of disease, suggesting strain-specific bacterial virulence. Circumstantial evidence furthermore supports strain-specific routes of bacterial dissemination. We conclude that PFGE and binary typing can be successfully applied for genetic analysis of S. aureusisolates from bovine mammary secretions. Binary typing in particular is a robust and simple method and promises to become a powerful tool for strain characterization, for resolution of clonal relationships of bacteria within and between host species, and for identification of sources and transmission routes of bovine S. aureus.


2020 ◽  
Vol 221 (Supplement_2) ◽  
pp. S215-S219
Author(s):  
Baixing Ding ◽  
Zhen Shen ◽  
Xiaohua Qin ◽  
Yang Yang ◽  
Xiaogang Xu ◽  
...  

Abstract Isolates of Enterobacteriaceae collected from the same patient can lose carbapenem susceptibility during antimicrobial therapy, but little attention has been given to how this conversion takes place. In the current study, we retrospectively analyzed microbiological and clinical data from patients with enterobacterial infections at a tertiary hospital in Shanghai, China. After screening 4795 patients and 7120 Enterobacteriaceae isolates over the 3-year study period, we found the change from carbapenem susceptible to carbapenem resistant in 41 pairs of isolates, of which 35 pairs (85.4%) were K. pneumoniae and 25 (61.0%) were from the same anatomic sites. Thirty-six isolate pairs showed different pulsed-field gel electrophoresis patterns between the carbapenem-susceptible and the corresponding resistant strain, and 5 pairs displayed identical pulsed-field gel electrophoresis patterns. Thirty-three (91.7%) of the 36 pairs of Enterobacteriaceae isolates were carbapenem-resistant K. pneumoniae with blaKPC-2, and 28 pairs (90.3%) of K. pneumoniae isolates had different sequence types (STs), with ST11 the most common ST found in carbapenem-resistant K. pneumoniae isolates. Forty of the 41 patients had received antimicrobial therapy such as carbapenems, cephalosporins, and fluoroquinolones, before the isolation of carbapenem-resistant Enterobacteriaceae. These results demonstrated that strain replacement is the main cause of emerging carbapenem resistance in Enterobacteriaceae during hospitalization. The loss of carbapenem susceptibility was not mainly due to in vivo development of carbapenem resistance.


2002 ◽  
Vol 68 (11) ◽  
pp. 5698-5703 ◽  
Author(s):  
Charlotte Nexmann Larsen ◽  
Birgit Nørrung ◽  
Helle Mølgaard Sommer ◽  
Mogens Jakobsen

ABSTRACT The virulence of different pulsed-field gel electrophoresis (PFGE) types of Listeria monocytogenes was examined by monitoring their ability to invade Caco-2 cells. Strains belonging to seven different PFGE types originating from both foods and humans were included. No significant differences in invasiveness were detected between strains isolated from humans and those isolated from food. Strains belonging to PFGE type 1 expressed a significantly lower ability to invade cells compared to strains belonging to other PFGE types. Although strains of PFGE type 2 also seemed to invade at a low level, this was not significant in the present study. PFGE types 1 and 2 as well as type 14 are more frequently found in food than the four other PFGE types examined and moreover have a relatively low prevalence in humans compared to their prevalence in food. Thus, the hypothesis that some PFGE types are less virulent than others is supported by this study showing that certain PFGE types of L. monocytogenes commonly found in food are less invasive than others to Caco-2 cells. In contrast to the differences in invasion, identical intracellular growth rates between the different PFGE types were observed. In vivo studies of the actual ability of the strains to invade the liver and spleen of cimetidine-treated rats following an oral dose of 109 L. monocytogenes cells were performed for isolates of PFGE types 1, 2, 5, and 15. After 2 days, equal amounts of bacteria were observed in the liver and spleen of the rats for any of the PFGE types tested.


OENO One ◽  
2007 ◽  
Vol 41 (3) ◽  
pp. 155
Author(s):  
Mar Vilanova ◽  
Sol Zamuz ◽  
Antón Masa ◽  
Carmen Sieiro

<p style="text-align: justify;"><strong>Aims</strong>: The aim of this work was realize a comparative study of two different methods of Saccharomycec cerevisiae yeast strain characterization.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Pulsed-field gel electrophoresis analysis (PFGE) and mitochondrial DNA (mtDNA) restriction analysis have been carried out to differentiate strains of Saccharomyces cerevisiae associated to Vitis vinifera musts from different Galicia wineyard (NW Spain). Seventeen strains isolated from wineries from Galicia were used in this study.</p><p style="text-align: justify;"><strong>Conclusion</strong>: The results have showed that although PFGE analysis technique has greater discriminatory power than mtDNA restriction analysis to detect genetic diversity in Saccharomyces cerevisiae, some clones with the same PFGE profile can only be differentiated by mtDNA restriction analysis.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: Pulsed-field gel electrophoresis analysis of chromosome (PFGE), by its discriminating power, constitute an ideal technique for the differentiation of Saccharomyces cerevisiae strains in biotechnological industries, however, mitochondrial DNA (mtDNA) restriction analysis is a rapid, simple and less expensive and time-consuming method. The results obtained demonstrate the value of using molecular genetic methods in taxonomic and ecological surveys.</p>


2021 ◽  
Vol 13 (3) ◽  
pp. 602-610
Author(s):  
Eugene Y. H. Yeung ◽  
Ivan Gorn

Pulsed-field gel electrophoresis (PFGE) has historically been considered the gold standard in fingerprinting bacterial strains in epidemiological studies and outbreak investigations; little is known regarding its use in individual clinical cases. The current study detailed two clinical cases in which PFGE helped to determine the source of their methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Patient A was found to have MRSA bacteremia after trauma in her pelvic area. MRSA was also found in her groin but not in her nostril and rectum. PFGE was performed that showed variable bands of her MRSA isolates from blood and groin, suggestive of different strains of MRSA. Her MRSA bacteremia was determined to be unrelated to her pelvic trauma. Patient B was found to have MRSA bacteremia after colonoscopy. MRSA was also found in his nostril and rectum. PFGE was performed that showed variable bands of his MRSA isolates from blood and rectum but identical bands of MRSA isolates from his blood and nostril. His MRSA bacteremia was determined to be unrelated to his colonoscopy procedure. The current study demonstrates the use of PFGE to rule out the source of bacteremia in individual clinical cases.


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