Aspects of plasmid F maintenance in Escherichia coli

1988 ◽  
Vol 34 (4) ◽  
pp. 526-535 ◽  
Author(s):  
Bruce C. Kline
Keyword(s):  
Escherichia Coli ◽  
Copy Number ◽  
Intracellular Distribution ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Major Class ◽  
Low Copy Number ◽  
Plasmid F ◽  
And Control

A major class of replicons in procaryotes is typified by low copy number, nonrandom intracellular distribution, and stable inheritance. Included in this class are chromosomes of gram-positive and gram-negative bacteria as well as a number of plasmids from these organisms. Replicons in this major class have remarkable structural and functional similarities in the genes that effect and control replication. In the present work a review of plasmid F is presented as a paradigm for many aspects of this group's maintenance features.

scholarly journals Active Stable Maintenance Functions in Low Copy-Number Plasmids of Gram-positive Bacteria. II. Post-Segregational Killing Systems

2013 ◽  
Vol 62 (1) ◽  
pp. 17-22 ◽  
Author(s):  
MICHAŁ DMOWSKI ◽  
GRAŻYNA JAGURA-BURDZY
Keyword(s):  
Cell Growth ◽  
Copy Number ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Daughter Cells ◽  
Low Copy Number ◽  
Stable Maintenance

Active support is needed for low copy-number plasmids to be stably maintained in bacterial cells. The mechanisms that fulfill this role are (i) partition systems (PAR) acting to separate plasmid molecules to daughter cells and (ii) toxin-andidote (TA) (post-segregational killing-PSK) systems which arrest cell growth until the plasmid reaches the correct copy-number or kill the cells that have not inherited the plasmid. Our knowledge of toxin-antidote systems comes mainly from studies on Gram-negative bacteria. However, some addiction systems of Gram-positive bacteria have been characterized in detail or recently identified. Altogether, they bring new interesting data on toxin-antidote functioning in bacteria.

scholarly journals Pyelonephritis in Pediatric Uropathic Patients: Differences from Community-Acquired Ones and Therapeutic Protocol Considerations. A 10-Year Single-Center Retrospective Study

Children ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 436
Author(s):  
Giovanni Parente ◽  
Tommaso Gargano ◽  
Stefania Pavia ◽  
Chiara Cordola ◽  
Marzia Vastano ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Retrospective Study ◽  
Success Rate ◽  
Pediatric Population ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Significant Difference ◽  
Klebsiella Spp

Pyelonephritis (PN) represents an important cause of morbidity in the pediatric population, especially in uropathic patients. The aim of the study is to demonstrate differences between PNs of uropathic patients and PNs acquired in community in terms of uropathogens involved and antibiotic sensitivity; moreover, to identify a proper empiric therapeutic strategy. A retrospective study was conducted on antibiograms on urine cultures from PNs in vesicoureteral reflux (VUR) patients admitted to pediatric surgery department and from PNs in not VUR patients admitted to Pediatric Emergency Unit between 2010 and 2020. We recorded 58 PNs in 33 patients affected by VUR and 112 PNs in the not VUR group. The mean age of not VUR patients at the PN episode was 1.3 ± 2.6 years (range: 20 days of life–3 years), and almost all the urine cultures, 111 (99.1%), isolated Gram-negative bacteria and rarely, 1 (0.9%), Gram-positive bacteria. The Gram-negative uropathogens isolated were Escherichia coli (97%), Proteus mirabilis (2%), and Klebsiella spp. (1%). The only Gram-positive bacteria isolated was an Enterococcus faecalis. As regards the antibiograms, 96% of not VUR PNs responded to beta-lactams, 99% to aminoglycosides, and 80% to sulfonamides. For the VUR group, mean age was 3.0 years ± 3.0 years (range: 9 days of life–11 years) and mean number of episodes per patient was 2.0 ± 1.0 (range: 1–5); 83% of PNs were by Gram-negatives bacteria vs. 17% by Gram-positive: the most important Gram-negative bacteria were Pseudomonas aeruginosa (44%), Escherichia coli (27%), and Klebsiella spp. (12%), while Enterococcus spp. determined 90% of Gram-positive UTIs. Regimen ampicillin/ceftazidime (success rate: 72.0%) was compared to ampicillin/amikacin (success rate of 83.0%): no statistically significant difference was found (p = 0.09). The pathogens of PNs in uropathic patients are different from those of community-acquired PNs, and clinicians should be aware of their peculiar antibiotic susceptibility. An empiric therapy based on the association ampicillin + ceftazidime is therefore suggested.

Effectiveness of Trisodium Phosphate, Acidified Sodium Chlorite, Citric Acid, and Peroxyacids against Pathogenic Bacteria on Poultry during Refrigerated Storage

2007 ◽  
Vol 70 (9) ◽  
pp. 2063-2071 ◽  
Author(s):  
ELENA del RÍO ◽  
REBECA MURIENTE ◽  
MIGUEL PRIETO ◽  
CARLOS ALONSO-CALLEJA ◽  
ROSA CAPITA
Keyword(s):  
Citric Acid ◽  
Salmonella Enteritidis ◽  
Pathogenic Bacteria ◽  
Trisodium Phosphate ◽  
Sodium Chlorite ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Microbial Group ◽  
And Control

The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 ± 1°C. All chemical solutions reduced microbial populations (P < 0.001) as compared with the control (untreated) samples. Similar bacterial loads (P > 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of storage, the pH of legs treated with TSP remained higher and that of legs treated with CA remained lower than normal.

Survival of some non-starter bacteria in naturally ripened and enzyme-accelerated Cheddar cheese

1988 ◽  
Vol 55 (4) ◽  
pp. 597-602 ◽  
Author(s):  
Lydia Bautista ◽  
Rohan G. Kroll
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Enzyme System ◽  
Cheddar Cheese ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Ripening Period ◽  
Gram Positive Bacteria

SummaryEffects of the addition of a proteinase (Neutrase 1–5S) and a peptidase (aminopeptidase DP-102) as agents for accelerating the ripening of Cheddar cheese on the survival of some non-starter bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coliand aSalmonellasp.) were studied throughout a 4-month ripening period. The enzymes were found to have no significant effect on the survival of the Gram-positive bacteria but some significant effects were observed, at some stages of the ripening period, with the Gram-negative bacteria in that lower levels were recovered from cheeses treated with the enzyme system.

scholarly journals Different Modes of Action of Naphthyridones in Gram-Positive and Gram-Negative Bacteria

2006 ◽  
Vol 50 (1) ◽  
pp. 385-387 ◽  
Author(s):  
Ed T. Buurman ◽  
Kenneth D. Johnson ◽  
Roxanne K. Kelly ◽  
Kathy MacCormack
Keyword(s):  
Escherichia Coli ◽  
Haemophilus Influenzae ◽  
Mode Of Action ◽  
Bacterial Pathogens ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Modes Of Action

ABSTRACT Naphthyridones that were recently described as a class of translation inhibitors in gram-positive bacteria mediate their mode of action via GyrA in Haemophilus influenzae and Escherichia coli. These are the first examples of compounds in which modes of action in different bacterial pathogens are mediated through widely different targets.

scholarly journals Asymmetric one-pot synthesis of cyclopropanes

2016 ◽  
Vol 35 (1) ◽  
pp. 45
Author(s):  
Naoufel Ben Hamadi ◽  
Ahlem Guesmi ◽  
Wided Nouira
Keyword(s):  
Escherichia Coli ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Protecting Group ◽  
Gram Positive ◽  
One Pot ◽  
Gram Negative ◽  
Activity Screening ◽  
High Yields

Cycloaddition of the diazoalkanes to electron-deficient olefins (in situ) affords polysubstituted cyclopropanes in high yields (up to 85%). Deprotection of the ketal protecting group provided water-soluble cyclopropane-bearing carbohydrate in good yields. Antimicrobial activity screening of the synthesized compounds 8 and 9, utilizing a variety of Gram-positive (Staphylococcus aureus and Enterococcus fecalis), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and yeast (Candida albicans), exhibited that all the prepared analogues acquire promising activities against both Gram-positive and Gram-negative bacteria especially compounds 9b and 9c (antimicrobial active agents against Gram-negative bacteria).

scholarly journals Paper modified with ZnO nanorods – antimicrobial studies

2012 ◽  
Vol 3 ◽  
pp. 684-691 ◽  
Author(s):  
Mayuree Jaisai ◽  
Sunandan Baruah ◽  
Joydeep Dutta
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Aspergillus Niger ◽  
Zno Nanorods ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Tissue Paper ◽  
Gram Positive Bacteria ◽  
Lighting Conditions

Paper with antimicrobial properties was developed through in situ growth of ZnO nanorods. The targeted application for this type of paper is in health centers as wallpaper, writing paper, facemasks, tissue paper, etc. The paper was tested on three model microbes, Gram-positive bacteriaStaphylococcus aureus,Gram-negative bacteriaEscherichia coliand common airborne fungusAspergillus niger. No viable bacterial colonies or fungal spores could be detected in the areas surrounding test samples of the antimicrobial paper. Gram-negative bacteriaEscherichia coliwere found to be inhibited in an area that is 239% and 163% the area of the paper sample under different room lighting conditions, i.e., halogen and fluorescent lamp illumination, respectively. For Gram-positive bacteriaStaphylococcus aureusthe zones of inhibition surrounding the paper samples are 102% and 70%, and forAspergillus niger, 224% and 183% of the sample area, under similar lighting conditions.

scholarly journals Antimicrobial Activity of Plant Extracts againstBacillus Subtilis,Staphylococcus Aureusand Escherichia Coli

2011 ◽  
Vol 8 (s1) ◽  
pp. S282-S284 ◽  
Author(s):  
Liliwirianis N ◽  
Wan Zuraida Wan Mohd Zain ◽  
Jamaluddin Kassim ◽  
Shaikh Abdul Karim
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Stemona Tuberosa ◽  
Elephantopus Scaber

Local herbs have many potential that may be active with antimicrobial activity. A screening was conducted with 11 species of herbs collected in UiTM Pahang Forest Reserve.Epipremnumsp.,Zingibersp.Tetracera indica, Tectaria crenata, Piper stylosum, Homalomena propinque, Goniothalamus sp., Elephantopus scaber, Mapania patiolale, Melastomasp.,Stemona tuberosa, Phullagathis rotundifolia, Thotea grandifoliaandSmilaxsp. were extracted with methanol to obtain their crude. The agar diffusion method using blank disc of 6 mm diameter were loaded with 1000 µg/mL of methanol crude and applied to the inoculate plate was used to assess the antimicrobial activity against two gram positive bacteria (Bacillus subtilisandStaphylococcus aeureus) and one gram negative bacteria (Escherichia coli). The results evaluated as the diameter of the inhibition zone of microbial growth, showed that all the extracts were active against gram-positive bacteria and gram-negative bacteria. The extract ofStemona tuberosewas found to be the most active against theE. coliandS. aeureuswhilePiper stylosumactive againstB. subtilis.

scholarly journals SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SILVER NANOPARTICLES STABILIZED BY CITRATE ANIONS

2020 ◽  
Vol 2020 (60) ◽  
pp. 127-135
Author(s):  
Liliya BAZYLYAK ◽  
◽  
Andriy KYTSYA ◽  
Ilona KARPENKO ◽  
Olena KARPENKO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Cell Walls ◽  
Colloidal Silver ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Vis Spectroscopy

Widespread use of synthetic antimicrobial drugs leads to the development of antibiotic resistance of pathogenic strains of microorganisms. Therefore, today researchers are very interested in drugs based on nanoparticles of metals, in particular silver and copper, which have antibacterial, antifungal and antiviral activity. One of the reasons for the high interest of researchers in AgNPs as an antimicrobial agent is the significantly lower toxicity of AgNPs compared to Ag+ ions. High antibacterial efficiency of silver nano¬particles is achieved due to their developed surface, which provides maximum contact with the environment. In addition, such nanoparticles are quite small and are able to penetrate cell membranes, to affect intracellular processes from within. Therefore, the aim of this work was to obtain concentrated colloidal silver solutions stabilized by citrate anions, which simultaneously provide satisfactory stabilization of colloidal silver solutions and are non-toxic, as well as to investigate the antimicrobial action of synthesized AgNPs. The solution of citrate stabilized silver nanoparticles (AgNPs) have been obtained via the reaction of reduction of silver nitrate by hydrazine in alkaline medium in the presence of sodium citrate. AgNPs were investigated using transmission electron microscopy (TEM) and UV-vis spectroscopy and the particles size and particles size distribution (PSD) were determined. It was observed that obtained AgNPs are mainly spherical shape. It was found that the mean diameter and PSD of AgNPs determined using TEM and UV-vis spectroscopy are close and equal to 14 and 5 nm and 15 and 4 nm respectively. Obtained solution was concentrated by evaporation at 70 C under reduced pressure up to achievement of AgNPs concentration equal to 200 mg/L. On the base of comparison of optical properties of initial silver sol and concentrated solution the minority of agglomeration of AgNPs was statement. At the same time AgNO3 test showed no change of UV-vis spectrum of concentrate that points on the absence of reducing agent in the solution; this fact indicate that hydrazine was eliminated from during the evaporation of initial AgNPs solution and obtained concentrate did not consist the toxic impurities. Antimicrobial activity of obtained citrate stabilised AgNPs against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacterium was tested using disk diffusion method. It was found that AgNPs shown significant bactericidal effect even at low (25 mg/L) concentration as well as some higher efficiency against Gram-negative bacterium. There was also a slightly higher antimicrobial activity of the drug against gram-negative bacteria Escherichia coli compared with gram-positive bacteria Bacillus subtilis, due to the different structure of cell walls. In particular, the walls of gram-positive bacteria consist mainly of peptidoglycan (murein), and gram-negative bacteria have cell walls with a layer of peptidoglycan and an outer membrane with a lipopolysaccharide component, which is not present in gram-positive bacteria. Based on the studies, it can be concluded that the proposed method of synthesis of AgNPs is suitable for obtaining highly concentrated silver sols. This method of synthesis is simple in hardware design, scalable, and the resulting colloidal solutions are stable and do not contain harmful impurities. Therefore, due to the high antibacterial activity of citrate-anion-stabilized AgNPs against certain types of gram-positive and gram-negative bacteria, it can be recommended for the manufacture of bactericidal drugs for biomedical purposes.

scholarly journals Determination of Patulin By TLC From Mouldy Apples

2010 ◽  
Vol 34 (1) ◽  
pp. 201-207
Author(s):  
Omar J. Al saree
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Inhibitory Effect ◽  
Gram Negative Bacteria ◽  
Zone Of Inhibition ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Tlc Plates

Analysis of the decayed apples (van. Starking delicious), collected from the localmarket, for patulin mycotoxin, using column chromotography and TLC Plates showedthat the presence of the amount of patulin mycotoxin in the mouldy tissues (1.3 , 2.5 ,3.4 , 4.2, 5.5, and 6.4 ) cm in diameters were (5.1, 5.8, 6.3, 10.5, 12.3, and 14 ) μgpatulin/g moldy tissues respectively. According to this research also, Patulinmycotoxin could diffused to the surrounding mouldy tissues. It is found that (0.5and0.2), (1.0 and 0.5), and (1.5 and 0.5) μg patulin/g tissues in the first and secondcentimeters after mouldy tissues 4.2, 5.5 and 6.4 cm respectively, this phenomenondue to the presence of intracellular spaces in the tissues which allow to patulin todiffuse from mouldy to the healthy tissues there was no patulin found in the othersurrounding healthy tissues. Gram positive bacteria found to be more susceptible topatulin, the zone of inhibition against Staphyllococcus aureus was 10 to 11 mm indiameter at concentration 10 and 30 mg /ml respectively when compared with 0.3μg/ml streptomycin and 0.06 μg/ml ciprofloxacin while no inhibitory effect foundagainst Gram negative bacteria Klebsiella pneumoniae and Escherichia coli

Sign in / Sign up

Export Citation Format

Share Document