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1.
Mol Cell ; 75(5): 1020-1030.e4, 2019 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-31350119

RESUMEN

Phage-inducible chromosomal islands (PICIs) represent a novel and universal class of mobile genetic elements, which have broad impact on bacterial virulence. In spite of their relevance, how the Gram-negative PICIs hijack the phage machinery for their own specific packaging and how they block phage reproduction remains to be determined. Using genetic and structural analyses, we solve the mystery here by showing that the Gram-negative PICIs encode a protein that simultaneously performs these processes. This protein, which we have named Rpp (for redirecting phage packaging), interacts with the phage terminase small subunit, forming a heterocomplex. This complex is unable to recognize the phage DNA, blocking phage packaging, but specifically binds to the PICI genome, promoting PICI packaging. Our studies reveal the mechanism of action that allows PICI dissemination in nature, introducing a new paradigm in the understanding of the biology of pathogenicity islands and therefore of bacterial pathogen evolution.


Asunto(s)
Bacteriófagos/fisiología , ADN Viral/metabolismo , Escherichia coli/virología , Islas Genómicas , Ensamble de Virus/fisiología , ADN Viral/genética , Endodesoxirribonucleasas/genética , Endodesoxirribonucleasas/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas Virales/genética , Proteínas Virales/metabolismo
2.
Nucleic Acids Res ; 50(19): 11109-11127, 2022 10 28.
Artículo en Inglés | MEDLINE | ID: mdl-36200825

RESUMEN

Mobile genetic elements control their life cycles by the expression of a master repressor, whose function must be disabled to allow the spread of these elements in nature. Here, we describe an unprecedented repression-derepression mechanism involved in the transfer of Staphylococcus aureus pathogenicity islands (SaPIs). Contrary to the classical phage and SaPI repressors, which are dimers, the SaPI1 repressor StlSaPI1 presents a unique tetrameric conformation never seen before. Importantly, not just one but two tetramers are required for SaPI1 repression, which increases the novelty of the system. To derepress SaPI1, the phage-encoded protein Sri binds to and induces a conformational change in the DNA binding domains of StlSaPI1, preventing the binding of the repressor to its cognate StlSaPI1 sites. Finally, our findings demonstrate that this system is not exclusive to SaPI1 but widespread in nature. Overall, our results characterize a novel repression-induction system involved in the transfer of MGE-encoded virulence factors in nature.


Asunto(s)
Islas Genómicas , Fagos de Staphylococcus , Islas Genómicas/genética , Fagos de Staphylococcus/genética , Staphylococcus aureus/genética
3.
Int J Mol Sci ; 24(11)2023 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-37298725

RESUMEN

Achillea fragrantissima, a desert plant commonly known as yarrow, is traditionally used as an antimicrobial agent in folklore medicine in Saudi Arabia. The current study was undertaken to determine its antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA) and multi-drug-resistant Pseudomonas aeruginosa (MDR-P. aeruginosa) using in vitro and in vivo studies. A biofilm model induced through an excision wound in diabetic mice was used to evaluate its effect in vivo. The skin irritation and cytotoxic effects of the extract were determined using mice and HaCaT cell lines, respectively. The Achillea fragrantissima methanolic extract was analyzed with LC-MS to detect different phytoconstituents, which revealed the presence of 47 different phytoconstituents. The extract inhibited the growth of both tested pathogens in vitro. It also increased the healing of biofilm-formed excision wounds, demonstrating its antibiofilm, antimicrobial, and wound-healing action in vivo. The effect of the extract was concentration-dependent, and its activity was stronger against MRSA than MDR-P. aeruginosa. The extract formulation was devoid of a skin irritation effect in vivo and cytotoxic effect on HaCaT cell lines in vitro.


Asunto(s)
Achillea , Antiinfecciosos , Diabetes Mellitus Experimental , Staphylococcus aureus Resistente a Meticilina , Ratones , Animales , Pseudomonas aeruginosa , Diabetes Mellitus Experimental/tratamiento farmacológico , Antiinfecciosos/farmacología , Biopelículas , Extractos Vegetales/farmacología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Pruebas de Sensibilidad Microbiana
4.
Molecules ; 27(23)2022 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-36500645

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infection worldwide. Clove oil's ability to inhibit the growth of MRSA was studied through in vitro and in vivo studies. The phytochemical components of clove oil were determined through gas chromatography-mass spectrometry (GC-MS) analysis. The antibacterial effects of clove oil and its interaction with imipenem were determined by studying MIC, MBC, and FIC indices in vitro. The in vivo wound-healing effect of the clove oil and infection control were determined using excision wound model rats. The GC-MS analysis of clove oil revealed the presence of 16 volatile compounds. Clove oil showed a good antibacterial effect in vitro but no interaction was observed with imipenem. Clove bud oil alone or in combination with imipenem healed wounds faster and reduced the microbial load in wounds. The findings of this study confirmed the antibacterial activity of clove oil in vitro and in vivo and demonstrated its interaction with imipenem.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Aceites Volátiles , Syzygium , Infección de Heridas , Ratas , Animales , Syzygium/química , Aceite de Clavo/farmacología , Aceite de Clavo/química , Imipenem/farmacología , Aceites Volátiles/farmacología , Aceites Volátiles/química , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Antibacterianos/química
5.
Open Vet J ; 14(6): 1417-1425, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-39055761

RESUMEN

Background: Escherichia coli is one of the serious pathogens causing various infections in the animal field, such as neonatal calf diarrhea, which is responsible for mortality associated with diarrhea during the first days of life. Aim: Current work is aimed at designing an effective and safe multiepitope vaccine candidate against E. coli infection in calves based on the fimbrial protein K99 of Enterotoxigenic E. coli (ETEC) and Immuno-informatics. Methods: A conserved sequence of K99 protein was generated, and then highly antigenic, nonallergic, and overlapped epitopes were used to construct a multiepitope vaccine. Five THL, six MHC II, and four beta cell epitopes were targeted to create the candidate. The candidate vaccine was produced utilizing 15 epitopes and three types of linkers, two types of untranslated region (UTR) human hemoglobin subunit beta (HBB), UTR beta-globin (Rabb), and RpfE protein as an immunomodulation adjuvant. Results: Immuno-informatics analysis of the constructed protein showed that the protein was antigenic (antigenic score of 0.8841), stable, nonallergen, and soluble. Furthermore, the Immuno-informatics and physiochemical analysis of the constructed protein showed a stable, nonallergic, soluble, hydrophilic, and acidic PI (isoelectric point). of 9.34. Docking of the candidate vaccine with the toll-like receptor TLR3 was performed, and results showed a strong interaction between the immune receptor and the vaccine. Finally, the expression efficiency of the construct in E. coli was estimated via computational cloning of the vaccine sequence into Pet28a. Conclusion: Results of immunoinformatics and in silico approaches reveal that the designed vaccine is antigenic, stable, and able to bind to the immune cell receptors. Our results interpret the proposed multiepitope mRNA vaccine as a good preventive option against E. coli infection in calves.


Asunto(s)
Enfermedades de los Bovinos , Biología Computacional , Escherichia coli Enterotoxigénica , Infecciones por Escherichia coli , Vacunas contra Escherichia coli , Animales , Bovinos , Escherichia coli Enterotoxigénica/inmunología , Infecciones por Escherichia coli/veterinaria , Infecciones por Escherichia coli/prevención & control , Infecciones por Escherichia coli/inmunología , Vacunas contra Escherichia coli/inmunología , Enfermedades de los Bovinos/prevención & control , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/microbiología , Epítopos/inmunología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Modelos Moleculares , Inmunoinformática
6.
Antibiotics (Basel) ; 12(8)2023 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-37627673

RESUMEN

The present study was conducted to investigate the chemical composition of Ailanthus altissima (Mill.) Swingle methanolic leaf extracts from geographically distinct regions and to assess their antimicrobial properties along with their ability to induce oxidative stress. The HPLC-DAD analysis revealed the presence of phenolic acids and flavonoids including chlorogenic acid, gallic acid, synapic acid, p-coumaric acid, apigenin, hyperoside, isoamnétine-3-O-beta-D-glucotrioside, quercetin, and isoquercetin in various amounts depending on the origin of tested extracts. The assessment of antibacterial activity showed the effectiveness of the A. altissima extracts particularly against Gram-positive bacteria, with inhibition zone diameters reaching 14 ± 1 mm and minimum inhibitory concentrations ranging from 4 to 72.2 mg/mL. These bioactive substances also exhibited strong antibiofilm activity with an eradication percentage reaching 67.07%. Furthermore, they increased ROS production to levels two to five times higher than the control group, altered the membrane integrity and caused lipid peroxidation with MDA production exceeding 2.5 µmol/mg protein in the Gram-positive and Gram-negative strains. A decrease in the levels of the antioxidant enzymes SOD and CAT was also observed, indicating an impairment of the bacterial response to the oxidative stress caused by the tested extracts. These findings highlight the antibacterial properties of A. altissima leaf extracts depending on their origins and promote their exploitation and application in the agro-food and pharmaceutical sectors.

7.
Microorganisms ; 11(3)2023 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-36985266

RESUMEN

The study developed a simple and inexpensive method to induce biofilm formation in-vivo for the evaluation of the antibiofilm activity of pharmacological agents using Swiss albino mice. Animals were made diabetic using streptozocin and nicotinamide. A cover slip containing preformed biofilm along with MRSA culture was introduced into the excision wound in these animals. The method was effective in developing biofilm on the coverslip after 24 h incubation in MRSA broth which was confirmed by microscopic examination and a crystal violet assay. Application of preformed biofilm along with microbial culture induced a profound infection with biofilm formation on excision wounds in 72 h. This was confirmed by macroscopic, histological, and bacterial load determination. Mupirocin, a known antibacterial agent effective against MRSA was used to demonstrate antibiofilm activity. Mupirocin was able to completely heal the excised wounds in 19 to 21 days while in the base-treated group, healing took place between 30 and 35 days. The method described is robust and can be reproduced easily without the use of transgenic animals and sophisticated methods such as confocal microscopy.

8.
PeerJ ; 11: e15272, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37101788

RESUMEN

Bacteriophages are the most abundant biological entity on the planet, having pivotal roles in bacterial ecology, animal and plant health, and in the biogeochemical cycles. Although, in principle, phages are simple entities that replicate at the expense of their bacterial hosts, due the importance of bacteria in all aspects of nature, they have the potential to influence and modify diverse processes, either in subtle or profound ways. Traditionally, the main application of bacteriophages is phage therapy, which is their utilization to combat and help to clear bacterial infections, from enteric diseases, to skin infections, chronic infections, sepsis, etc. Nevertheless, phages can also be potentially used for several other tasks, including food preservation, disinfection of surfaces, treatment of several dysbioses, and modulation of microbiomes. Phages may also be used as tools for the treatment of non-bacterial infections and pest control in agriculture; moreover, they can be used to decrease bacterial virulence and antibiotic resistance and even to combat global warming. In this review manuscript we discuss these possible applications and promote their implementation.


Asunto(s)
Infecciones Bacterianas , Bacteriófagos , Terapia de Fagos , Animales , Bacterias , Infecciones Bacterianas/terapia
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