scholarly journals Hyper-recombinogenity of the chimeric protein RecAX53 (Esherichia coli/Pseudomonas aeruginosa) is caused by its increased dynamics

2008 ◽  
Vol 6 (4) ◽  
pp. 47-54
Author(s):  
Daria B Chervyakova ◽  
Vladislav A Lanzov

RecAX53 is the most recombinogenic protein among the chimeric RecA proteins composed ofEsherichia coli RecA (RecAEc) and Pseudomonas aeruginosa RecA (RecAPa) protein fragments. We found out that RecAX53 protein is more rapid in ATP hydrolysis, dissociation from single-stranded DNA (ssDNA), SSB protein displacement from ssDNA and in association with doublestranded DNA (dsDNA), as compared with RecAEc and RecAPa proteins. These results indicate that the RecAX53 hyper-recombinogenity is caused by high dynamics of this protein - by its rapid association with and dissociation from ssDNA. The ability of RecAX53 to bind actively with dsDNA accounts for the SOS-independent mechanism of hyper-recombination used by this protein.

2001 ◽  
Vol 75 (15) ◽  
pp. 7206-7209 ◽  
Author(s):  
Vivien V. McDougal ◽  
Linda A. Guarino

ABSTRACT P143 is a DNA helicase that tightly binds both double-stranded and single-stranded DNA. DNA-protein complexes rapidly dissociated in the presence of ATP and Mg2+. This finding suggests that ATP hydrolysis causes a conformational change in P143 which decreases affinity for DNA. This supports the model of an inchworm mechanism of DNA unwinding.


2019 ◽  
Vol 5 (11) ◽  
pp. 1843-1854 ◽  
Author(s):  
Tuan-Dung Ngo ◽  
Sophie Plé ◽  
Aline Thomas ◽  
Caroline Barette ◽  
Antoine Fortuné ◽  
...  

2021 ◽  
Author(s):  
Ilknur Erdem ◽  
Ilker Yildirim ◽  
Birol Safak ◽  
Ritvan Karaali ◽  
Berna Erdal ◽  
...  

Abstract OBJECTIVE: ‘Nosocomial infections’ or ‘healthcare associated infections’ are a significant public health problem around the world. This study aimed to assess the rate of culture confirmed nosocomial infections (NIs), frequency of nosocomial pathogens and the antimicrobial resistance patterns of bacterial isolates in a University Hospital. METHODS: A retrospective evaluation of NIs in a tertiary hospital, between the years 2015 and 2019 in Tekirdag, Turkey. RESULTS : During the five years, the overall incidence rates (NI/100) and incidence densities (NI/1000 days of stay) of NIs were 2.04% (range 1.76-2.41/100) and 3.50/1000 patients-days (range 2.85-4.64/1000), respectively. 57.4 % of the infections were originated from the Intensive Care Units. The most common NIs according to the primary sites were bloodstream infections (55.3 %) and, pneumonia (20.4%). 67.5% of the isolated microorganisms as nosocomial agents were Gram negative bacteria, 24.9% of Gram positive bacteria and 7.6 % of candida. The most frequently isolated causative agents were Esherichia coli (16.7%) and Pseudomonas aeruginosa (15.7%). The rate of extended spectrum beta-lactamase production among E. coli isolates was 51.1%. Carbapenem resistance was 29.8% among isolates of Pseudomonas aeruginosa; 95.1% among isolates of Acinetobacter baumannii, 18.2% among isolates of Klebsiella pneumoniae. Colistin resistance was 2.4% among isolates of Acinetobacter baumannii. Vancomycin resistance was 5.3% among isolates of Enterococci.CONCLUSION: Our study results demonstrates the microorganisms of isolated from Intensive Care Units demonstrates high level resistance to many antimicrobial agents. The rising in incidence of multidrug-resistant microorganisms indicate that more interventions are urgently needed to reduce NIs in our ICUs.


2021 ◽  
Author(s):  
Silvia Hormeno ◽  
Oliver J Wilkinson ◽  
Clara Aicart-Ramos ◽  
Sahiti Kuppa ◽  
Edwin Antony ◽  
...  

Human HELB is a poorly-characterised helicase suggested to play both positive and negative regulatory roles in DNA replication and recombination. In this work, we used bulk and single molecule approaches to characterise the biochemical activities of HELB protein with a particular focus on its interactions with RPA and RPA-ssDNA filaments. HELB is a monomeric protein which binds tightly to ssDNA with a site size of ~20 nucleotides. It couples ATP hydrolysis to translocation along ssDNA in the 5′-to-3′ direction accompanied by the formation of DNA loops and with an efficiency of 1 ATP per base. HELB also displays classical helicase activity but this is very weak in the absence of an assisting force. HELB binds specifically to human RPA which enhances its ATPase and ssDNA translocase activities but inhibits DNA unwinding. Direct observation of HELB on RPA nucleoprotein filaments shows that translocating HELB concomitantly clears RPA from single-stranded DNA.


2013 ◽  
Vol 38 (3) ◽  
pp. 79-83 ◽  
Author(s):  
S Ahmad

Antibiotic resistance of urinary tract pathogens has increased worldwide. The purpose of this study is to provide information regarding the causative agents of urinary tract infection in Kashmiri patients, identify the uropathogens responsible for the infection and study the antibiotic susceptibility patterns of the uropathogens. Clean voided mid-stream urine samples were collected from 2190 patients. The specimens were cultured and the isolates were identified using standard microbiological techniques. The antibiotic susceptibilities of the isolates were also determined. Of 2190 specimens, 591 (27%) showed significant growth upon culture. Approximately 84.1 % (497/591) of the 591 patients with UTI were females, most of which belonged to the 21-30 age group (206). The males accounted for 15.9% (94/591) UTI cases. Most of the male patients belonged to the 21-30 age group (34). The lowest incidence of urinary tract infections was seen among the 13-20 years age group. Throughout this study males accounted for only 16% of all UTI cases. Esherichia coli was the most predominant isolate, 53.8% followed by Klebsiella pneumoniae 22.4% and Pseudomonas aeruginosa 7.6%. All isolates were fully sensitive to ofloxacin, and more than 94% were sensitive to cefuroxime. Apart from group D Streptococcus , the overall response to ampicillin by all isolates was less than 15%. The prevalence of multi-resistant Pseudomonas aeruginosa in community-acquired urinary tract infections is increasing. All Pseudomonas aeruginosa isolates were fully susceptible to cefuroxime and ofloxacin. It is recommended that cefuroxime and ofloxacin or both are used in the blind treatment of urinary tract infection while awaiting the culture and sensitivity results. Concurrent with the necessary shift in the prescription pattern, attention should be paid to restriction of antibiotic abuse in the community to retard development of further drug resistance. DOI: http://dx.doi.org/10.3329/bmrcb.v38i3.14330 Bangladesh Med Res Counc Bull 2012; 38(3): 79-83 (December)


2012 ◽  
Vol 418 (1-2) ◽  
pp. 32-46 ◽  
Author(s):  
Eric J. Tomko ◽  
Christopher J. Fischer ◽  
Timothy M. Lohman

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