scholarly journals Ultrastructural Variability of the Exosporium Layer of Clostridium difficile Spores

2016 ◽  
Vol 82 (7) ◽  
pp. 2202-2209 ◽  
Author(s):  
Marjorie Pizarro-Guajardo ◽  
Paulina Calderón-Romero ◽  
Pablo Castro-Córdova ◽  
Paola Mora-Uribe ◽  
Daniel Paredes-Sabja
Keyword(s):  
Clostridium Difficile ◽  
Electron Micrographs ◽  
Culture Conditions ◽  
Transmission Electron Micrographs ◽  
Spore Form ◽  
Content Type ◽  
Host Interactions ◽  
Link Type ◽  
Lack Of Information ◽  
Transmission Electron

ABSTRACTThe anaerobic sporeformerClostridium difficileis the leading cause of nosocomial antibiotic-associated diarrhea in developed and developing countries. The metabolically dormant spore form is considered the transmission, infectious, and persistent morphotype, and the outermost exosporium layer is likely to play a major role in spore-host interactions during the first contact ofC. difficilespores with the host and for spore persistence during recurrent episodes of infection. Although some studies on the biology of the exosporium have been conducted (J. Barra-Carrasco et al., J Bacteriol 195:3863–3875, 2013,http://dx.doi.org/10.1128/JB.00369-13; J. Phetcharaburanin et al., Mol Microbiol 92:1025–1038, 2014,http://dx.doi.org/10.1111/mmi.12611), there is a lack of information on the ultrastructural variability and stability of this layer. In this work, using transmission electron micrographs, we analyzed the variability of the spore's outermost layers in various strains and found distinctive variability in the ultrastructural morphotype of the exosporium within and between strains. Through transmission electron micrographs, we observed that although this layer was stable during spore purification, it was partially lost after 6 months of storage at room temperature. These observations were confirmed by indirect immunofluorescence microscopy, where a significant decrease in the levels of two exosporium markers, the N-terminal domain of BclA1 and CdeC, was observed. It is also noteworthy that the presence of the exosporium marker CdeC on spores obtained fromC. difficilebiofilms depended on the biofilm culture conditions and the strain used. Collectively, these results provide information on the heterogeneity and stability of the exosporium surface ofC. difficilespores. These findings have direct implications and should be considered in the development of novel methods to diagnose and/or removeC. difficilespores by using exosporium proteins as targets.

scholarly journals Ultrastructure Variability of the Exosporium Layer of Clostridium difficile Spores from Sporulating Cultures and Biofilms

2016 ◽  
Vol 82 (19) ◽  
pp. 5892-5898 ◽  
Author(s):  
Marjorie Pizarro-Guajardo ◽  
Paulina Calderón-Romero ◽  
Daniel Paredes-Sabja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clostridium Difficile ◽  
Detailed Knowledge ◽  
Spore Form ◽  
Content Type ◽  
Host Interactions ◽  
Definitive Evidence ◽  
Transmission Electron ◽  
Biofilm Development

ABSTRACTThe anaerobic sporeformerClostridium difficileis the leading cause of nosocomial antibiotic-associated diarrhea in developed and developing countries. The metabolically dormant spore form is considered the morphotype responsible for transmission, infection, and persistence, and the outermost exosporium layer is likely to play a major role in spore-host interactions during recurrent infections, contributing to the persistence of the spore in the host. A recent study (M. Pizarro-Guajardo, P. Calderón-Romero, P. Castro-Córdova, P. Mora-Uribe, and D. Paredes-Sabja, Appl Environ Microbiol 82:2202–2209, 2016,http://dx.doi.org/10.1128/AEM.03410-15) demonstrated by transmission electron microscopy the presence of two ultrastructural morphotypes of the exosporium layer in spores formed from the same sporulating culture. However, whether these distinct morphotypes appeared due to purification techniques and whether they appeared during biofilm development remain unclear. In this communication, we demonstrate through transmission electron microscopy that these two exosporium morphotypes are formed under sporulation conditions and are also present in spores formed during biofilm development. In summary, this work provides definitive evidence that in a population of sporulating cells, spores with a thick outermost exosporium layer and spores with a thin outermost exosporium layer are formed.IMPORTANCEClostridium difficilespores are recognized as the morphotype of persistence and transmission ofC. difficileinfections. Spores ofC. difficileare intrinsically resistant to all known antibiotic therapies. Development of spore-based removal strategies requires a detailed knowledge of the spore surface for proper antigen selection. In this context, in this work we provide definitive evidence that two types of spores, those with a thick outermost exosporium layer and those with a thin outermost exosporium layer, are formed in the sameC. difficilesporulating culture or during biofilm development.

scholarly journals Complete Genome Sequences and Transmission Electron Micrographs of Listeria Phages of the Genus Homburgvirus

2019 ◽  
Vol 8 (41) ◽  
Author(s):  
Lauren K. Hudson ◽  
Tracey L. Peters ◽  
Yaxiong Song ◽  
Thomas G. Denes
Keyword(s):  
New York ◽  
Listeria Monocytogenes ◽  
Electron Micrographs ◽  
Complete Genome ◽  
Foodborne Pathogen ◽  
Dairy Farms ◽  
Transmission Electron Micrographs ◽  
Genome Sequences ◽  
Content Type ◽  
Transmission Electron

Bacteriophages that infect the foodborne pathogen Listeria monocytogenes were previously isolated from New York dairy farms. The complete genome sequences for three of these Listeria phages, with genome sizes of 64.6 to 65.7 kb, are presented here. Listeria phages LP-010, LP-013, and LP-031-2 are siphoviruses that belong to the genus Homburgvirus.

scholarly journals Phyllobacterium loti sp. nov. isolated from nodules of Lotus corniculatus

2014 ◽  
Vol 64 (Pt_3) ◽  
pp. 781-786 ◽  
Author(s):  
Maximo Sánchez ◽  
Martha-Helena Ramírez-Bahena ◽  
Alvaro Peix ◽  
María J. Lorite ◽  
Juan Sanjuán ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Similarity ◽  
Carbon Sources ◽  
Lotus Corniculatus ◽  
Culture Conditions ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
The 16S Rrna Gene

Strain S658T was isolated from a Lotus corniculatus nodule in a soil sample obtained in Uruguay. Phylogenetic analysis of the 16S rRNA gene and atpD gene showed that this strain clustered within the genus Phyllobacterium . The closest related species was, in both cases, Phyllobacterium trifolii PETP02T with 99.8 % sequence similarity in the 16S rRNA gene and 96.1 % in the atpD gene. The 16S rRNA gene contains an insert at the beginning of the sequence that has no similarities with other inserts present in the same gene in described rhizobial species. Ubiquinone Q-10 was the only quinone detected. Strain S658T differed from its closest relatives through its growth in diverse culture conditions and in the assimilation of several carbon sources. It was not able to reproduce nodules in Lotus corniculatus. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain should be classified as a representative of a novel species of the genus Phyllobacterium , for which the name Phyllobacterium loti sp. nov. is proposed. The type strain is S658T( = LMG 27289T = CECT 8230T).

scholarly journals Identifying Atoms in High Resolution Transmission Electron Micrographs Using a Deep Convolutional Neural Net

2018 ◽  
Vol 24 (S1) ◽  
pp. 512-513 ◽  
Author(s):  
Jakob Schiøtz ◽  
Jacob Madsen ◽  
Pei Liu ◽  
Ole Winther ◽  
Jens Kling ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Micrographs ◽  
Transmission Electron Micrographs ◽  
Neural Net ◽  
Transmission Electron
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