scholarly journals Study of the contribution of active defense mechanisms to ciprofloxacin tolerance in Escherichia coli growing at different rates

2022 ◽  
Author(s):  
Galina V. Smirnova ◽  
Aleksey V. Tyulenev ◽  
Nadezda G. Muzyka ◽  
Oleg N. Oktyabrsky
Keyword(s):  
Escherichia Coli ◽  
Defense Mechanisms ◽  
Active Defense

scholarly journals Cooperative Immune Suppression by Escherichia coli and Shigella Effector Proteins

2018 ◽  
Vol 86 (4) ◽  
Author(s):  
Maarten F. de Jong ◽  
Neal M. Alto
Keyword(s):  
Escherichia Coli ◽  
Defense Mechanisms ◽  
Immune Defense ◽  
Effector Proteins ◽  
Innate Immune ◽  
Host Cells ◽  
Secretion Systems ◽  
Content Type ◽  
E Coli ◽  
Type Iii Secretion Systems

ABSTRACT The enteric attaching and effacing (A/E) pathogens enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) and the invasive pathogens enteroinvasive E. coli (EIEC) and Shigella encode type III secretion systems (T3SS) used to inject effector proteins into human host cells during infection. Among these are a group of effectors required for NF-κB-mediated host immune evasion. Recent studies have identified several effector proteins from A/E pathogens and EIEC/ Shigella that are involved in suppression of NF-κB and have uncovered their cellular and molecular functions. A novel mechanism among these effectors from both groups of pathogens is to coordinate effector function during infection. This cooperativity among effector proteins explains how bacterial pathogens are able to effectively suppress innate immune defense mechanisms in response to diverse classes of immune receptor signaling complexes (RSCs) stimulated during infection.

scholarly journals Active defense mechanisms of thorny catfish

2020 ◽  
Vol 38 ◽  
pp. 35-48 ◽  
Author(s):  
Haocheng Quan ◽  
Wen Yang ◽  
Zixiang Tang ◽  
Robert O. Ritchie ◽  
Marc A. Meyers
Keyword(s):  
Defense Mechanisms ◽  
Active Defense

scholarly journals Alternative treatment approaches of urinary tract infections caused by uropathogenic Escherichia coli strains

2019 ◽  
Author(s):  
Beata Maria Zalewska-Piątek ◽  
Rafał Janusz Piątek
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Defense Mechanisms ◽  
Uropathogenic Escherichia Coli ◽  
Alternative Methods ◽  
Secretion Pathway ◽  
Etiologic Agents ◽  
Tract Infections ◽  
Bacterial Interference

Urinary tract infections (UTIs) are the most widespread and annoying infections affecting millions of people every year annually. The biggest problems of urinary diseases are recurrences, increasing resistance of uropathogens to commonly used antibiotics, as well as the high health care costs of afflicted persons. Uropathogenic Escherichia coli strains (UPECs) are the most dominant etiologic agents of community-acquired infections of this type. During UTI pathogenesis, UPECs utilize various virulence factors, especially mono- and polyadhesive appendages of the chaperone-usher secretion pathway (CUP) required for adhesion, invasion and biofilm formation. Commonly used antibiotics for UTI treatment are usually effective, but their long-term utility may affect gut microbiota of the treated individuals and cause selection of drug resistant uropathogenic variants. Due to increasing resistance of UPEC strains to antibiotics via the evolution of specific defense mechanisms, there is a need to develop alternative methods and therapeutic strategies to fight UTIs (vaccines, receptor analogues, pilicides and curlicides, bacterial interference or phagotherapy). Such therapeutic approaches usually target processes enabling uropathogens to survive within the urinary tract and cause recurrent infections.

scholarly journals Molecular Identification of a Sexual Interloper: The Pear Pathogen, Venturia pirina, has Sex on Apple

2001 ◽  
Vol 91 (7) ◽  
pp. 633-641 ◽  
Author(s):  
Christiane Stehmann ◽  
Shaun Pennycook ◽  
Kim M. Plummer
Keyword(s):  
Defense Mechanisms ◽  
Apple Scab ◽  
Fruit Trees ◽  
First Record ◽  
Morphological Characters ◽  
Active Defense ◽  
Apple Leaves ◽  
Venturia Pirina ◽  
Species Specific ◽  
Polymerase Chain Reaction Primers

Venturia pirina (the pear scab pathogen) and V. inaequalis (the apple scab pathogen) were detected as ascospores discharged from apple leaf litter in New Zealand (spring 1998). Pseudothecia of both species were located on dead apple leaves; however, only those of V. inaequalis were associated with scab lesions. V. pirina was identified by rDNA sequence analyses, because morphological characters could not distinguish this fungus from V. asperata (a rare saprophyte on apple) and other Venturia spp. pathogenic on rosaceous fruit trees. Species-specific polymerase chain reaction primers designed to the 18S end of the internal transcribed spacer 1 region differentiated Venturia fruit tree pathogens reliably. V. pirina field isolates were pathogenic on pear, but only weak saprophytes on apple. In rare instances, when appressoria of V. pirina appeared to penetrate the cuticle of apple leaves, epidermal cells responded with a localized hypersensitive response (HR). To our knowledge, this is the first report of induction of HR-like events by V. pirina on its nonhost, apple, and also the first record of sexual reproduction of V. pirina on apple. It is assumed that V. pirina pseudothecia formed from saprophytic lesions in senescing apple leaves when active defense mechanisms such as HR were no longer induced.

Effect of Trans-Cinnamaldehyde on preformed biofilm and biofilm formation of Escherichia coli isolated from urine specimens

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Eman Adel El-Haddad ◽  
Soha Abdel Rahman El-Hady ◽  
Amira Esmail Abdel Hamid ◽  
Hisham Abdel Majeed Fahim
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Defense Mechanisms ◽  
Colorimetric Assay ◽  
Biofilm Inhibition ◽  
Hospital Acquired Infection ◽  
E Coli ◽  
Before And After ◽  
Tract Infections ◽  
Hospital Acquired

Abstract Introduction Bacteria in most environments exist as communities of sessile cells in a selfproduced polymeric matrix known as biofilms. Biofilms are responsible for more than 80% of infections, including urinary tract infections (UTI). UTI is the most common hospital acquired infection, caused mainly by Escherichia coli (E.coli). E. coli can readily form biofilm in such infections, specially in the presence of indwelling urinary catheter. It’s difficult to eradicate bacteria in biofilms, since they are shielded from the host defense mechanisms as phagocytes and antibodies, as well as antibiotics. Searching for alternative or adjuvant substances for prevention and eradication of biofilm associated infections are therefore urgently needed. Aim of the work Studying the efficacy of the trans-cinnamaldehyde (TC) for preventing E. coli biofilm formation. Materials and methods Thirty isolates of E.coli were obtained from urine samples. To test the effect of TC on E.coli biofilm formation and preformed biofilms, microtitre plates (MTP) were inoculated with the isolated E.coli and were treated with different concentrations of TC and incubated at 37° C. A colorimetric assay was used to assess biofilm inhibition and inactivation and optical densities (OD) were compared before and after adding different TC concentrations. Results The mean OD of the isolated E.coli biofilms was 1.3 and significantly decreased when mixed with TC different concentrations. TC had high activity in inhibition of preformed E.coli biofilms, where no biofilm was detected on MTP treated with 1.25% and 1.5% TC. Conclusion TC inhibited the biofilm forming ability of E.coli isolates could fully inactivate formed biofilms, suggesting its possibility to be used as an anti-biofilm agent or adjuvant in preventing and treating UTI caused by biofilm producing E.coli.

scholarly journals The AcrAB-TolC Efflux Pump Impacts Persistence and Resistance Development in Stationary-Phase Escherichia coli Following Delafloxacin Treatment

2021 ◽  
Author(s):  
Brandon A. Byrd ◽  
Blesing Zenick ◽  
Maria C. Rocha-Granados ◽  
Hanna E. Englander ◽  
Patricia J. Hare ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Defense Mechanisms ◽  
Efflux Pump ◽  
Resistance Development ◽  
E Coli ◽  
Target Dna ◽  
Clonal Cultures ◽  
Chemical Inhibition ◽  
High Doses

Bacteria have a repertoire of strategies to overcome antibiotics in clinical use, complicating our ability to treat and cure infectious diseases. In addition to evolving resistance, bacteria within genetically clonal cultures can undergo transient phenotypic changes and tolerate high doses of antibiotics. These cells, termed persisters, exhibit heterogeneous phenotypes: the strategies that a bacterial population deploys to overcome one class of antibiotics can be distinct from those needed to survive treatment with drugs with another mode of action. It was previously reported that fluoroquinolones, which target DNA topoisomerases, retain the capacity to kill non-growing bacteria that tolerate other classes of antibiotics. Here, we show that in Escherichia coli stationary-phase cultures and colony biofilms, persisters that survive treatment with the anionic fluoroquinolone Delafloxacin depend on the AcrAB-TolC efflux pump. In contrast, we did not detect this dependence on AcrAB-TolC in E. coli persisters that survive treatment with three other fluroquinolone compounds. We found that the loss of AcrAB-TolC activity via genetic mutations or chemical inhibition not only reduces Delafloxacin persistence in non-growing E. coli MG1655 or EDL933 (an E. coli O157:H7 strain), it limits resistance development in progenies derived from Delafloxacin persisters that were given the opportunity to recover in nutritive media following antibiotic treatment. Our findings highlight the heterogeneity in defense mechanisms that persisters use to overcome different compounds within the same class of antibiotics. They further indicate that efflux pump inhibitors can potentiate the activity of Delafloxacin against stationary-phase E. coli and block resistance development in Delafloxacin persister progenies.

scholarly journals Inhibition of Apoptosis by Escherichia coli K1 Is Accompanied by Increased Expression of BclXL and Blockade of Mitochondrial Cytochrome c Release in Macrophages

2004 ◽  
Vol 72 (10) ◽  
pp. 6012-6022 ◽  
Author(s):  
Sunil K. Sukumaran ◽  
Suresh K. Selvaraj ◽  
Nemani V. Prasadarao
Keyword(s):  
Escherichia Coli ◽  
Cell Lines ◽  
Defense Mechanisms ◽  
Mrna Level ◽  
Protein A ◽  
Gene Array ◽  
Macrophage Cell ◽  
Cytochrome C Release ◽  
E Coli ◽  
Monocytes And Macrophages

ABSTRACT Escherichia coli K1 survival in the blood is a critical step for the onset of meningitis in neonates. Therefore, the circulating bacteria are impelled to avoid host defense mechanisms by finding a niche to survive and multiply. Our recent studies have shown that E. coli K1 enters and survives in both monocytes and macrophages in the newborn rat model of meningitis as well as in macrophage cell lines. Here we demonstrate that E. coli K1 not only extends the survival of human and murine infected macrophage cell lines but also renders them resistant to apoptosis induced by staurosporine. Macrophages infected with wild-type E. coli expressing outer membrane protein A (OmpA), but not with OmpA− E. coli, are resistant to DNA fragmentation and phosphatidylserine exposure induced by staurosporine. Infection with OmpA+ E. coli induces the expression of BclXL, an antiapoptotic protein, both at the mRNA level as assessed by gene array analysis and at the protein level as evaluated by immunoblotting. OmpA− E. coli infection of macrophages induced the release of cytochrome c from mitochondria into the cytosol and the activation of caspases 3, 6, and 9, events that were significantly blocked in OmpA+ E. coli-infected macrophages. In addition, OmpA+ E. coli-infected cells were resistant to a decrease in the transmembrane potential of mitochondria induced by staurosporine as measured by the MitoCapture fluorescence technique. Complementation of OmpA− E. coli with a plasmid containing the ompA gene restored the ability of OmpA− E. coli to inhibit the apoptosis of infected macrophages, further demonstrating that E. coli OmpA expression is critical for inducing macrophage survival and thereby finding a safe haven for its growth.

scholarly journals Purification and Properties of Proline-Rich Antimicrobial Peptides from Sheep and Goat Leukocytes

1999 ◽  
Vol 67 (8) ◽  
pp. 4106-4111 ◽  
Author(s):  
Olga Shamova ◽  
Kim A. Brogden ◽  
Chengquan Zhao ◽  
Tung Nguyen ◽  
Vladimir N. Kokryakov ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Host Defense ◽  
Defense Mechanisms ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Purification And Properties

ABSTRACT We purified three proline-rich antimicrobial peptides from elastase-treated extracts of sheep and goat leukocytes and subjected two of them, OaBac5α and ChBac5, to detailed analysis. OaBac5α and ChBac5 were homologous to each other and to bovine Bac5. Both exhibited potent, broad-spectrum antimicrobial activity under low-concentration salt conditions. While the peptides remained active againstEscherichia coli, Pseudomonas aeruginosa,Bacillus subtilis, and Listeria monocytogenesin 100 mM NaCl, they lost activity against Staphylococcus aureus and Candida albicans under these conditions. ChBac5 was shown to bind lipopolysaccharide, a property that could enhance its ability to kill gram-negative bacteria. Proline-rich Bac5 peptides are highly conserved in ruminants and may contribute significantly to their innate host defense mechanisms.

scholarly journals Defense responses of sunflower plants to the fungal pathogen attack

Biljni lekar ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 510-521
Author(s):  
Slobodan Krsmanović ◽  
Kristina Petrović ◽  
Boško Dedić ◽  
Ferenc Bagi ◽  
Vera Stojšin ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Fungal Pathogens ◽  
Plant Protection ◽  
Induced Defense ◽  
Research Work ◽  
Defense Responses ◽  
Phytopathogenic Fungi ◽  
Active Defense ◽  
Expression Of Genes ◽  
The Republic

Sunflower plants show pronounced allelopathic traits and represent a suitable base for potential scientific research work. Understanding and exploiting precisely of that potential could greatly reduce the use of chemical products for plant protection that are intensively used in the production technology of this crop. Today, a big effort is made in sunflower breeding in order to produce the resistance to the economically most important pathogens, which are in most cases phytopathogenic fungi and parasitic weeds such as broomrape. Since sunflower is an increasingly popular crop within farmer fields in the Republic of Serbia, an overview of so far known, passive and active defense mechanisms, that are key for the crop resistance creating, is given. The study also describes in detail, the interactions among the most harmful fungal pathogens and sunflower plants, the expression of genes caused by their attack, and the production of metabolites that are crucial for the induced defense formation.

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