Biology subjects

Logel, D. Y.

Publications and source records attributed to Logel, D. Y..

6 recordsLinked to original sources

bioRxiv2024

Discovery and characterisation of new phage targeting uropathogenic Escherichia coli

Antimicrobial resistance (AMR) is increasing at an escalating rate with few new therapeutic options in the pipeline. Urinary tract infections (UTIs) are one of the most prevalent bacterial infections globally and are particularly prone to becoming recurrent and antibiotic resistant. The aim of this study was to discover and characterise new bacterial viruses (phage) against uropathogenic Escherichia coli (UPEC), which is the leading cause of UTIs. Six phages from the Autographiviridae family and Guernseyvirinae sub-family were isolated from wastewater and sequenced. The length of the isolated phage genomes was between 39,471 bp and 45,233 bp, with a GC content between 45.0% and 51.0%, and 57 to 84 predicted coding sequences (CDS) per genome. These phages were found to infect between 25 - 75% of the twelve UPEC strains tested. Using sequence comparison and predicted structural alignments, we show a similarity between the C-terminal domain of the tail fiber proteins of two phage that correlates with their host range. In vitro characterisation of phage cocktails against a single bacterial strain did not perform better than the best-performing phage, but did show synergistic improvement against a mixed UPEC strain population. Lastly, we measured the effectiveness of treatment with phage with different lytic kinetics in a sequential treatment and found it was improved over single phage treatment.

microbiology↗

bioRxiv2022

IbpAB small heat shock proteins are not host factors for bacteriophage {varphi}X174 replication

Bacteriophages exploit host proteins for successful infection. Small heat shock proteins are a universally conserved family of stress-induced molecular chaperones that prevent irreversible aggregation of proteins. Two small heat shock proteins, IbpA and IbpB, are a class of holding modulators or "holdases", which bind partially folded proteins and await ATP-driven folding chaperones for refolding. Bacteriophage {phi}X174 is a small, icosahedral, and non-tailed virus belonging to the Microviridae. During {phi}X174 infection of Escherichia coli C122, IbpA and IbpB were previously found to be the most highly upregulated host proteins, with expression levels comparable to {phi}X174 proteins. In this work, to understand the role of IbpA and IbpB during {phi}X174 infection, we used a hybrid approach of CRISPR interference and genomic knockouts to disrupt the ibpA and ibpB genes. We show that these two proteins do not appear to be necessary for efficient {phi}X174 replication, and moreover, their absence has no effect on {phi}X174 fecundity. ImportanceThe small heat shock proteins (sHsps) are universally conserved family of stress-induced molecular chaperones that prevent irreversible protein aggregation. In E. coli, the IbpA/B sHsps work together, and separately, to bind partially folded proteins and await ATP-driven folding chaperones for refolding. These proteins are highly upregulated during protein overexpression and bacteriophage infection, but their collective role in bacteriophage infection has not been investigated. Here, we show that the ibpA/B genes are dispensable for bacteriophage {phi}X174 infection, and are likely not essential host factors despite their abundance during diverse phage infections. Instead, this work points towards their role as cell wall integrity sensors, similar to the phage shock protein system, in addition to their canonical role as holdases of cytoplasmic protein.

microbiology↗

bioRxiv2022

Creating De Novo Overlapped Genes

Future applications of synthetic biology will rely on deploying engineered cells outside of lab environments for long periods of time. Currently, a significant roadblock to this application is the potential for deactivating mutations in engineered genes. A recently developed method to protect engineered coding sequences from mutation is called Constraining Adaptive Mutations using Engineered Overlapping Sequences (CAMEOS). In this chapter we provide a workflow for utilising CAMEOS to create synthetic overlaps between two genes, one essential (infA) and one non-essential (aroB), to protect the non-essential gene from mutation and loss of protein function. In this workflow we detail the methods to collect large numbers of related protein sequences, produce multiple sequence alignments (MSAs), use the MSAs to generate Hidden Markov Models and Markov Random Field models, and finally generate a library of overlapping coding sequences through CAMEOS scripts. To assist practitioners with basic coding skills to try out the CAMEOS method, we have created a virtual machine containing all the required packages already installed, that can be downloaded and run locally.

synthetic biology↗

bioRxiv2021

A Codon Constrained Method for Both Eliminating and Creating Intragenic Bacterial Promoters

Future applications of synthetic biology will require refactored genetic sequences devoid of internal regulatory elements within coding sequences. These regulatory elements include cryptic and intragenic promoters which may constitute up to a third of predicted Escherichia coli promoters. Promoter activity is dependent on the structural interaction of core bases with a {sigma} factor. Rational engineering can be used to alter key promoter element nucleotides interacting with {sigma} factors and eliminate downstream transcriptional activity. In this paper, we present COdon Restrained Promoter SilEncing (CORPSE), a system for removing intragenic promoters. CORPSE exploits the DNA-{sigma} factor structural relationship to disrupt {sigma}70 promoters embedded within gene coding sequences, with a minimum of synonymous codon changes. Additionally, we present an inverted CORPSE system, iCORPSE, which can create highly active promoters within a gene sequence while not perturbing the function of the modified gene.

synthetic biology↗

bioRxiv2020

Proteomic and transcriptomic analysis of Microviridae {varphi}X174 infection reveals broad up-regulation of host membrane damage and heat shock responses

Measuring host-bacteriophage dynamics is an important approach to understanding bacterial survival functions and responses to infection. The model Microviridae bacteriophage {varphi}X174 is endemic to the human gut and has been studied for over seventy years but the host response to infection has never been investigated in detail. To address this gap in our understanding of this important interaction within our microbiome we have measured host Escherichia coli C proteomic and transcriptomic response to {varphi}X174 infection. We used mass spectrometry and RNA-seq to identify and quantify all 11 {varphi}X174 proteins and over 1,700 E. coli proteins, enabling us to comprehensively map host pathways involved in {varphi}X174 infection. Most notably, we see significant host responses centered on membrane damage and remodeling, cellular chaperone and translocon activity, and lipoprotein processing, which we speculate is due to the peptidoglycan-disruptive effects of the {varphi}X174 lysis protein E on MraY activity. We also observe the massive upregulation of small heat-shock proteins IbpA/B, along with other heat shock pathway chaperones, and speculate on how the specific characteristics of holdase protein activity may be beneficial for viral infections. Together, this study enables us to begin to understand the proteomic and transcriptomic host responses of E. coli to Microviridae infections and contributes insights to the activities of this important model phage. IMPORTANCEA major part of the healthy human gut microbiome are the Microviridae bacteriophage, exemplified by the model {varphi}X174 phage. Although much has been learned from studying {varphi}X174 over the last half century, until this work, the E. coli host response to infection has never been investigated in detail. We reveal the proteomic and transcriptomic pathways differentially regulated during the {varphi}X174 infection cycle, and uncover the details of a coordinated cellular response to membrane damage that results in increased lipoprotein processing and membrane trafficking, likely due to the phage antibiotic-like lysis protein. We also reveal that small heat shock proteins IbpA/B are massively upregulated during infection and that these holdase chaperones are highly conserved across the domains of life, indicating that reliance on them is likely widespread across viruses.

microbiology↗

bioRxiv2020

A high-resolution map of bacteriophage {Phi}X174 transcription

Bacteriophage oX174 is a model virus for studies across the fields of structural biology, genetics, gut microbiome, and synthetic biology, but did not have a high-resolution transcriptome until this work. In this study we used next-generation sequencing to measure the RNA produced from oX174 while infecting its host E. coli C. We broadly confirm the past transcriptome model while revealing several interesting deviations from previous knowledge. Additionally, we measure the strength of canonical oX174 promoters and terminators and discover both a putative new promoter that may be activated by heat shock sigma factors, as well as rediscover a controversial Rho-dependent terminator. We also provide evidence for the first antisense transcription observed in the Microviridae family, identify two promoters that may be involved in generating this transcriptional activity, and discuss possible reasons why this RNA may be produced.

genomics↗