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Diseases of the Nervous System
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Diphtheria is a disease caused by the lysogenic strains of Corynebacterium diphtheriae.393,597 During active infection, prophage genomes are incorporated into DNA. The disease is now rare in most countries due to the fact that children are immunized at an early age. Absorption occurs at the local site of bacillar infection and most intensely following pharyngeal and bronchial infections.248 Diphtheria toxin is extremely potent, 10-4 mg will kill a guinea pig.130,248,449 it exerts a profound action of the peripheral nervous system causing extensive proximal demyelination in the ganglia and adjacent nerve roots, mainly in places where the blood-brain barrier is incomplete. Cardiac effects are also very frequent, mainly connected with abnormalities of carnitine metabolism leading to decreased oxidation of long chain fatty acids and accumulation of triglycerides.610
Physiology and Growth
Published in Paul Pumpens, Single-Stranded RNA Phages, 2020
In contrast to the lytic cycle of the phage reproduction, the lysogenic cycle assumes formation of a prophage that is either integration of the phage genome into the host bacterium's genome or formation of a circular replicon in the bacterial cytoplasm, while the host cell continues to live and reproduce normally. Although absence of the elements complementary to the RNA phage genome in the host's chromosome (Doi and Spiegelman 1962) and full independence of the phage replication from the DNA synthesis (Cooper and Zinder 1962; Knolle and Kaudewitz 1964) were established at the first steps of the RNA phage studies, the idea of the putative lysogeny persisted.
Bacteriophage Involvement in Neurodegenerative Diseases
Published in David Perlmutter, The Microbiome and the Brain, 2019
As we previously described, the majority of microorganisms carry prophage DNA in their genomes that, under certain conditions, can lead to productive phage infections and bacterial death; it is particularly important to note the possible interaction between E. coli, E. coli phages, and Alzheimer’s. E. coli is known to harbor multiple temperate prophage genomes and is identified as a hallmark microorganism in the brain of Alzheimer’s patients.45 Therefore, it is highly likely that the E. coli present in Alzheimer’s brains and cerebrospinal fluid would also carry prophages; death by prophage activation would result in PAMP release, including E. coli DNA to the cerebrospinal fluid, thereby triggering neuroinflammation.66E. coli DNA is known to be implicated in the formation of bacterial prions in biofilms and is associated with transkingdom triggering of misfolded protein deposition in the mammalian brain when susceptible animals are colonized with amyloid-producing E. coli.57
Bacteriophages for ESKAPE: role in pathogenicity and measures of control
Published in Expert Review of Anti-infective Therapy, 2021
Amrita Patil, Rajashri Banerji, Poonam Kanojiya, Santosh Koratkar, Sunil Saroj
The phenotype of the bacteria is often governed by the extrachromosomal genetic components such as genomes of plasmids and bacteriophages. The manipulation through such genetic elements leads to increased resistance to antibiotics and enhanced pathogenicity through toxin synthesis. Several virulence factors encoded within the bacteriophage genome can regulate the virulence properties of the bacteria. In recent years, prophages have been the focus of research, as they deliver myriad advantages to the bacterial host (lysogen), such as increased resistance to antibiotics, virulence, and overall fitness of the bacterial host [113]. Prophages possess cargo genes known as morons involved in the virulence potential of host bacteria [114]. Relative genomics studies have revealed that the genomes of bacteria and their bacteriophages are coevolving, leading to increasing the pathogenicity of bacteria by bacteriophage [114].
Gut bacteriophage dynamics during fecal microbial transplantation in subjects with metabolic syndrome
Published in Gut Microbes, 2021
Pilar Manrique, Yifan Zhu, John van der Oost, Hilde Herrema, Max Nieuwdorp, Willem M. de Vos, Mark Young
Changes in the phage community of recipients after recipients might arise from two different sources (Figure 1): (1) establishment of donor invading phages, and (2) changes in the recipient’s phage community profile. Invading phages can be extracellular donor phages that successfully find and infect a host in the recipient’s established microbial community or donor prophages that are transferred inside their ‘Trojan bacterial-horse’ (phage integrated in the bacterial host genome).37 Similar to donor invading bacterial strains, donor invading phages can be transferred and maintained through time in the recipient, but typically constitute a small percentage of the post-FMT phage community.39 Changes in the recipient’s phage community that is successfully established will be primarily due to activation of previously inactive recipient prophages, as well as an increase in the relative abundance of pre-FMT low-abundance phages. The biggest changes were seen in the profile of the bacteriophages that were unique to the MetS recipient, particularly when they received a healthy donor stool sample, suggesting that the new community and the donor-community are able to displace these types of bacteriophages. Future studies directed at the mechanism(s) of phage establishment and the direct function that phage play during FMT treatment in shaping the function and structure of gut microbial community are warranted.
Lactic acid bacteria and bifidobacteria deliberately introduced into the agro-food chain do not significantly increase the antimicrobial resistance gene pool
Published in Gut Microbes, 2022
Vita Rozman, Petra Mohar Lorbeg, Primož Treven, Tomaž Accetto, Majda Golob, Irena Zdovc, Bojana Bogovič Matijašić
Annotation of the MGE genes allowed the classification of elements into groups based on their signature genes. A putative MGE was annotated as an ICE if it encoded an integrase, a relaxase, and a type IV secretion system, whereas an IME did not contain type IV secretion system genes. MGEs containing an integrase or a relaxase were classified as IME-like elements and elements containing a replicase (Rep) as plasmids. MGEs carrying a transposase were annotated as insertion sequences. Two insertion sequences of the same group were typical of a composite transposon. Prophages contained phage gene homologs, while a phage-inducible chromosomal island lacked structural and lytic genes.