scholarly journals Staphylococcal phages and pathogenicity islands drive plasmid evolution

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Suzanne Humphrey ◽  
Álvaro San Millán ◽  
Macarena Toll-Riera ◽  
John Connolly ◽  
Alejandra Flor-Duro ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Plasmid Transfer ◽  
Pathogenicity Islands ◽  
Bimodal Size Distribution ◽  
Plasmid Evolution ◽  
Selective Pressures ◽  
Transmissible Plasmid ◽  
Bacterial Plasmid ◽  
Packaging Efficiency ◽  
Average Size

AbstractConjugation has classically been considered the main mechanism driving plasmid transfer in nature. Yet bacteria frequently carry so-called non-transmissible plasmids, raising questions about how these plasmids spread. Interestingly, the size of many mobilisable and non-transmissible plasmids coincides with the average size of phages (~40 kb) or that of a family of pathogenicity islands, the phage-inducible chromosomal islands (PICIs, ~11 kb). Here, we show that phages and PICIs from Staphylococcus aureus can mediate intra- and inter-species plasmid transfer via generalised transduction, potentially contributing to non-transmissible plasmid spread in nature. Further, staphylococcal PICIs enhance plasmid packaging efficiency, and phages and PICIs exert selective pressures on plasmids via the physical capacity of their capsids, explaining the bimodal size distribution observed for non-conjugative plasmids. Our results highlight that transducing agents (phages, PICIs) have important roles in bacterial plasmid evolution and, potentially, in antimicrobial resistance transmission.

scholarly journals Role of Staphylococcal Phage and SaPI Integrase in Intra- and Interspecies SaPI Transfer

2007 ◽  
Vol 189 (15) ◽  
pp. 5608-5616 ◽  
Author(s):  
Elisa Maiques ◽  
Carles Úbeda ◽  
María Ángeles Tormo ◽  
María Desamparados Ferrer ◽  
Íñigo Lasa ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Special Reference ◽  
Attachment Site ◽  
Pathogenicity Islands ◽  
Specific Attachment ◽  
Generalized Transduction

ABSTRACT SaPIbov2 is a member of the SaPI family of staphylococcal pathogenicity islands and is very closely related to SaPIbov1. Typically, certain temperate phages can induce excision and replication of one or more of these islands and can package them into special small phage-like particles commensurate with their genome sizes (referred to as the excision-replication-packaging [ERP] cycle). We have studied the phage-SaPI interaction in some depth using SaPIbov2, with special reference to the role of its integrase. We demonstrate here that SaPIbov2 can be induced to replicate by different staphylococcal phages. After replication, SaPIbov2 is efficiently encapsidated and transferred to recipient organisms, including different non-Staphylococcus aureus staphylococci, where it integrates at a SaPI-specific attachment site, attC , by means of a self-coded integrase (Int). Phages that cannot induce the SaPIbov2 ERP cycle can transfer the island by recA-dependent classical generalized transduction and can also transfer it by a novel mechanism that requires the expression of SaPIbov2 int in the recipient but not in the donor. It is suggested that this mechanism involves the encapsidation of standard transducing fragments containing the intact island followed by int-mediated excision, circularization, and integration in the recipient.

scholarly journals Convergent evolution of pathogenicity islands in helper cos phage interference

2016 ◽  
Vol 371 (1707) ◽  
pp. 20150505 ◽  
Author(s):  
Nuria Carpena ◽  
Keith A. Manning ◽  
Terje Dokland ◽  
Alberto Marina ◽  
José R. Penadés
Keyword(s):  
Staphylococcus Aureus ◽  
Life Cycle ◽  
Convergent Evolution ◽  
Pathogenicity Islands ◽  
Capsid Assembly ◽  
Helper Phage ◽  
Phage Capsid ◽  
Helper Phages

Staphylococcus aureus pathogenicity islands (SaPIs) are phage satellites that exploit the life cycle of their helper phages for their own benefit. Most SaPIs are packaged by their helper phages using a headful ( pac ) packaging mechanism. These SaPIs interfere with pac phage reproduction through a variety of strategies, including the redirection of phage capsid assembly to form small capsids, a process that depends on the expression of the SaPI-encoded cpm A and cpm B genes. Another SaPI subfamily is induced and packaged by cos -type phages, and although these cos SaPIs also block the life cycle of their inducing phages, the basis for this mechanism of interference remains to be deciphered. Here we have identified and characterized one mechanism by which the SaPIs interfere with cos phage reproduction. This mechanism depends on a SaPI-encoded gene, ccm , which encodes a protein involved in the production of small isometric capsids, compared with the prolate helper phage capsids. As the Ccm and CpmAB proteins are completely unrelated in sequence, this strategy represents a fascinating example of convergent evolution. Moreover, this result also indicates that the production of SaPI-sized particles is a widespread strategy of phage interference conserved during SaPI evolution. This article is part of the themed issue ‘The new bacteriology’.

scholarly journals Sip, an integrase protein with excision, circularization and integration activities, defines a new family of mobile Staphylococcus aureus pathogenicity islands

2003 ◽  
Vol 49 (1) ◽  
pp. 193-210 ◽  
Author(s):  
Carles Úbeda ◽  
Ma. Ángeles Tormo ◽  
Carme Cucarella ◽  
Pilar Trotonda ◽  
Timothy J. Foster ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenicity Islands ◽  
New Family ◽  
Integrase Protein

Room-temperature synthesis of submicron platinum and palladium powders in glycols

1999 ◽  
Vol 14 (9) ◽  
pp. 3707-3712 ◽  
Author(s):  
K. Tekaia-Elhsissen ◽  
F. Bonet ◽  
S. Grugeon ◽  
S. Lambert ◽  
R. Herrera-Urbina
Keyword(s):  
Size Distribution ◽  
Room Temperature ◽  
Spherical Particles ◽  
Average Particle ◽  
Particle Sizes ◽  
Temperature Synthesis ◽  
Bimodal Size Distribution ◽  
Hydrazine Reduction ◽  
Average Size ◽  
Palladium Particles

Platinum and palladium powders with average particle sizes in the submicron range have been synthesized at room temperature by hydrazine reduction of and , respectively, in glycols. Platinum powders contain spherical particles with a bimodal size distribution. Palladium powders also contain spherical particles, but the size distribution is narrow. The effect of both ammonia and hydrazine concentration on the size distribution and average size of palladium particles was investigated.

scholarly journals Green synthesis of silver nanoparticles using aqueous extract of Citrus sinensis peels and evaluation of their antibacterial efficacy

2021 ◽  
Vol 10 (1) ◽  
pp. 851-859
Author(s):  
Lebogang Mogole ◽  
Wesley Omwoyo ◽  
Elvera Viljoen ◽  
Makwena Moloto
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Citrus Sinensis ◽  
Antimicrobial Activities ◽  
Antibacterial Efficacy ◽  
Gram Positive ◽  
Gram Negative ◽  
Average Size ◽  
Passivating Agent

Abstract The resistance of microorganisms towards antibiotics remains a big challenge in medicine. Silver nanoparticles (AgNPs) received attention recently for their characteristic nanosized features and their ability to display antimicrobial activities. This work reports the synthesis of AgNPs using the Citrus sinensis peels extract in their aqueous, mild, and less hazardous conditions. The effect of concentration variation (1%, 2%, and 3%) of the plant extracts on the size and shape of the AgNPs was investigated. The antimicrobial activities were tested against gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae. Absorption spectra confirmed the synthesis by the surface Plasmon resonance peaks in the range 400–450 nm for all the AgNPs. FTIR spectra confirmed that Citrus sinensis peels extract acted as both reducing and surface passivating agent for the synthesized AgNPs. TEM revealed spherical AgNPs with average size of 12 nm for 3% concentration as compared to the agglomeration at 1% and 2%. All the AgNPs synthesized using Citrus sinensis peels extracts (1%, 2%, and 3%) exhibited antimicrobial activity against both gram-positive and negative bacteria. These results indicated a simple, fast, and inexpensive synthesis of silver nanoparticles using the Citrus sinensis peels extract that has promising antibacterial activity.

scholarly journals Synthesis and Characterization of La0.8Sr0.2Ga0.8Mg0.2O3-δ Nano-Particle by Aerosol Plasma Pyrolysis

2010 ◽  
Vol 445 ◽  
pp. 82-85
Author(s):  
Kenichi Myoujin ◽  
Araki Toriyama ◽  
Takayuki Kodera ◽  
Takashi Ogihara
Keyword(s):  
Metal Nitrate ◽  
Nano Particle ◽  
X Ray Diffraction ◽  
Bimodal Size Distribution ◽  
Primary Particles ◽  
Plasma Pyrolysis ◽  
Xrd Patterns ◽  
Average Size ◽  
Precursor Powders

Spherical La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) precursor powders were synthesized by aerosol plasma pyrolysis using an aqueous solution of metal nitrate. As-prepared powders obtained by this method were found to have a spherical morphology with a bimodal size distribution of nanosized (primary) and submicron-sized (secondary) particles. The average size of the primary particles was less than 100 nm. X-ray diffraction (XRD) patterns showed that as-prepared powders crystallized to LSGM and other phases. XRD revealed that LSGM pellets were crystallized to a perovskite structure after sintering at 1300 °C for 10 h.

Efektivitas Kompres Iodine Terhadap Zona Hambat Staphylococcus Aureus Pada Ulkus Diabetikum

2013 ◽  
Vol 16 (3) ◽  
pp. 139-144
Author(s):  
Asep Kuswandi ◽  
Kusmiyati Kusmiyati ◽  
Holikin Holikin
Keyword(s):  
Staphylococcus Aureus ◽  
Diabetic Foot ◽  
Wound Care ◽  
Positive Culture ◽  
Foot Ulcers ◽  
Distilled Water ◽  
Diabetic Foot Ulcers ◽  
Average Size

AbstrakUlkus diabetikum merupakan salah satu komplikasi kronis diabetes melitus dan menjadi penyebab amputasi kaki. Infeksi pada ulkus tersebut umumnya disebabkan oleh Staphylococcus aureus. Salah satu teknik pencegahan amputasi kaki diabetes adalah perawatan ulkus. Berbagai jenis bahan kompres ulkus diabetikum yang telah dikenal selama ini adalah:kompres madu, gula, Iodine, dan NaCl 0,9%. Penelitian ini bertujuan mengetahui efektifitas bahan kompres ulkus terhadap daya hambat Staphylococcus aureus. Penelitian ini merupakan penelitian eksperimen in vitro menggunakan satu faktor perlakuan yaitu zona hambat bahan kompres terhadap Staphylococcus aureus pada ulkus diabetikum. Enam jenis bahan yang diuji adalah aquadest, gula, Iodine 10%, campuran gula dan Iodine 10 %, madu, dan NaCl 0,9 %. Eksperimen dilakukan sebanyak 10 kali untuk mengetahui rerata luas daya hambatnya selama 24 jam. Sampel diambil dari ulkus diabetikum. Staphylococcus aureus diisolasi dari ulkus tersebut untuk eksperimen dengan berbagai bahan kompres ulkus. Hasil penelitian menunjukkan bahwa zona hambat madu rata-rata sebesar 0,4 mm, gula 3,0 mm, aquadest 0,0 mm, NaCl 0,9% 0,0 mm, Iodine 10% 8,3 mm dan campuran gula-Iodine 6,0 mm. Zona hambat terluas dihasilkan dari uji menggunakkan Iodine 10% (8,3 mm). Sementara campuran gula Iodine 10% menghasilkan zona hambat seluas 6 mm dan gula menghasilkan 3 mm. Penelitian ini merekomendasikan jika ditemukan Staphylococcus aureus maka dilakukan kompres Iodine 10% dengan kasa steril. Penelitian selanjutnya dengan metode in vivo perlu dilakukan untuk mengetahui efektifitas cairan Iodine pada ulkus diabetikum.Kata Kunci: kompres ulkus, staphylococcus aureus, ulkus diabetikum, zona hambatAbstractEffectivity of Iodine Compress to Blocking Zone of Staphylococcus aureus in Diabetes Ulcers. Diabetic foot ulcers is one of diabetes chronic complications that might lead to leg amputations. Staphylococcus aureus is known as the cause of infection in diabetic foot ulcers. One of techniques to prevent diabetic foot amputations is wound care. Various materials are known to be used to compress diabetic foot ulcers. These include of using honey, sugar, 10% of Iodine and 0.9% of NaCl. This study aimed ttify to identify the effectiveness of various wound care materials to block Staphylococcus aureus. This is an in vitro experiment study to investigate the effetiveness of six wound care materials used to wounds compress: distilled water, sugar, 10% of Iodine, a mixture of sugar and Iodine, honey and 0.9% of NaCl. Experiments were carried out in 10 times to determine the average size of block area in 24 hours. Staphylococcus aureus were isolated and soiled with various wound compressss materialls. The results showed that honey produced 0.4 mm of a blocking zone, 3.0 mm for glucose, 0.0 mm for distilled water, 0.0 mm for 0.9% of NaCl, 8.3 mm for 10% of Iodine, and 6.0 mm for mixed-Iodine Sugar. Ten percents of Iodine produced the widest zone to block Staphylicoccus aureus. This study recommends of apllying a 10% of Iodine compress if there is a positive culture of Staphylococcus aureus. A further in vivo study is a necessity to investigate the effectiveness of Iodine to diabetes foot ulcers.Keywords: blocking zone, diabetic foot ulcers, Staphylococcus aureus, wound compress

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