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Biomedical subjects

Mauro Petrillo

Publications and source records attributed to Mauro Petrillo.

7 recordsLinked to original sources

Toward a unified approach: Considerations for bioinformatic and sequencing activities & data in wastewater surveillance of biologic public health threats.

Genomic technologies such as PCR and next-generation sequencing (NGS) have greatly advanced public health surveillance, especially during COVID-19, by enabling detailed tracking of pathogen spread, origins, and variants. While PCR is vital for targeted detection, falling NGS costs have made large-scale, high-throughput sequencing more feasible, supporting broader pathogen monitoring-including the detection of vaccine escape variants and new strains. Applying NGS to wastewater offers valuable population-level insights but faces challenges such as variable sample complexity, the need for skilled staff, suitable platforms, and robust IT infrastructure. Although there are currently a lot of efforts towards defining guidelines for sampling, analysis, and integrating wastewater data into public health policy, such as the recently published International Cookbook for Wastewater Practitioners, they often lack universal applicability, emphasizing the analytical approaches in favour of the NGS-based approaches. However, standardising protocols for sampling, sequencing, and analysis is crucial to ensure reliable, comparable data across surveillance systems worldwide. Pilot studies and continuous refinement are recommended to overcome implementation hurdles and fully realise the benefits of NGS in wastewater surveillance. This work attempts to outline these challenges and opportunities across the entire wastewater surveillance workflow, from data generation to reporting, and provide some concrete suggestions and considerations across the spectrum of activities. We further highlight that the infrastructure, funding and government-policy context in which surveillance operates acts as an enabling condition for these activities, and that technical standardisation alone is unlikely to deliver durable, comparable surveillance in its absence.

considerations↗

Misdetection of frameshifts in SARS-CoV-2 genomes: need for additional harmonisation and efficient monitoring of data workflows.

Five years after the outbreak of the SARS-CoV-2 pandemic in 2020, diagnostic laboratories have moved from massive sequencing of thousands of samples to routine surveillance of SARS-CoV-2 cases, as with all other respiratory viruses. Surveillance remains of paramount importance to prevent a further SARS-CoV-2 surge, as the virus has been shown to mutate rapidly and can render available drugs and vaccines ineffective. During the pandemic, several bioinformatics pipelines and workflows have been developed to streamline analysis, shorten turnaround time and ensure reproducibility. As the number of samples decreases, laboratories are moving towards more flexible sequencing strategies and optimizing the cost per sample. However, workflow redesigns, even if individual steps have proven successful time and time again, can lead to challenges when changes in a bioinformatics pipeline are introduced (e.g. version updates, implementation of new features, etc.), a new combination of viral mutations emerge or a change in wet-lab procedures leads to unpredictable results. Here, we present a report of misidentified frameshift mutations in the consensus sequence of SARS-CoV-2, which led to an incorrect assumption of mutations in the spike and nucleocapsid viral proteins with the potential to affect PCR detection or even antigen testing. This investigation exemplifies the need for better awareness of the challenges that can occur even when using routinely applied protocols and analytical workflows and highlights the need for cooperation between experts of NGS, bioinformaticians and decision-makers towards more harmonized data workflows.

SARS-CoV-2↗

PathoSeq-QC: a decision support bioinformatics workflow for robust genomic surveillance.

MOTIVATION: Recommendations on the use of genomics for pathogens surveillance are evidence that high-throughput genomic sequencing plays a key role to fight global health threats. Coupled with bioinformatics and other data types (e.g., epidemiological information), genomics is used to obtain knowledge on health pathogenic threats and insights on their evolution, to monitor pathogens spread, and to evaluate the effectiveness of countermeasures. From a decision-making policy perspective, it is essential to ensure the entire process's quality before relying on analysis results as evidence. Available workflows usually offer quality assessment tools that are primarily focused on the quality of raw NGS reads but often struggle to keep pace with new technologies and threats, and fail to provide a robust consensus on results, necessitating manual evaluation of multiple tool outputs. RESULTS: We present PathoSeq-QC, a bioinformatics decision support workflow developed to improve the trustworthiness of genomic surveillance analyses and conclusions. Designed for SARS-CoV-2, it is suitable for any viral threat. In the specific case of SARS-CoV-2, PathoSeq-QC: (i) evaluates the quality of the raw data; (ii) assesses whether the analysed sample is composed by single or multiple lineages; (iii) produces robust variant calling results via multi-tool comparison; (iv) reports whether the produced data are in support of a recombinant virus, a novel or an already known lineage. The tool is modular, which will allow easy functionalities extension. AVAILABILITY AND IMPLEMENTATION: PathoSeq-QC is a command-line tool written in Python and R. The code is available at https://code.europa.eu/dighealth/pathoseq-qc.

Genomics↗

Stem-loop structures in prokaryotic genomes.

BACKGROUND: Prediction of secondary structures in the expressed sequences of bacterial genomes allows to investigate spontaneous folding of the corresponding RNA. This is particularly relevant in untranslated mRNA regions, where base pairing is less affected by interactions with the translation machinery. Relatively large stem-loops significantly contribute to the formation of more complex secondary structures, often important for the activity of sequence elements controlling gene expression. RESULTS: Systematic analysis of the distribution of stem-loop structures (SLSs) in 40 wholly-sequenced bacterial genomes is presented. SLSs were searched as stems measuring at least 12 bp, bordering loops 5 to 100 nt in length. G-U pairing in the stems was allowed. SLSs found in natural genomes are constantly more numerous and stable than those expected to randomly form in sequences of comparable size and composition. The large majority of SLSs fall within protein-coding regions but enrichment of specific, non random, SLS sub-populations of higher stability was observed within the intergenic regions of the chromosomes of several species. In low-GC firmicutes, most higher stability intergenic SLSs resemble canonical rho-independent transcriptional terminators, but very frequently feature at the 5'-end an additional A-rich stretch complementary to the 3' uridines. In all species, a clearly biased SLS distribution was observed within the intergenic space, with most concentrating at the 3'-end side of flanking CDSs. Some intergenic SLS regions are members of novel repeated sequence families. CONCLUSION: In depth analysis of SLS features and distribution in 40 different bacterial genomes showed the presence of non random populations of such structures in all species. Many of these structures are plausibly transcribed, and might be involved in the control of transcription termination, or might serve as RNA elements which can enhance either the stability or the turnover of cotranscribed mRNAs. Three previously undescribed families of repeated sequences were found in Yersiniae, Bordetellae and Enterococci.

Base Composition↗

Systematic analysis of human kinase genes: a large number of genes and alternative splicing events result in functional and structural diversity.

BACKGROUND: Protein kinases are a well defined family of proteins, characterized by the presence of a common kinase catalytic domain and playing a significant role in many important cellular processes, such as proliferation, maintenance of cell shape, apoptosis. In many members of the family, additional non-kinase domains contribute further specialization, resulting in subcellular localization, protein binding and regulation of activity, among others. About 500 genes encode members of the kinase family in the human genome, and although many of them represent well known genes, a larger number of genes code for proteins of more recent identification, or for unknown proteins identified as kinase only after computational studies. RESULTS: A systematic in silico study performed on the human genome, led to the identification of 5 genes, on chromosome 1, 11, 13, 15 and 16 respectively, and 1 pseudogene on chromosome X; some of these genes are reported as kinases from NCBI but are absent in other databases, such as KinBase. Comparative analysis of 483 gene regions and subsequent computational analysis, aimed at identifying unannotated exons, indicates that a large number of kinase may code for alternately spliced forms or be incorrectly annotated. An InterProScan automated analysis was performed to study domain distribution and combination in the various families. At the same time, other structural features were also added to the annotation process, including the putative presence of transmembrane alpha helices, and the cystein propensity to participate into a disulfide bridge. CONCLUSION: The predicted human kinome was extended by identifying both additional genes and potential splice variants, resulting in a varied panorama where functionality may be searched at the gene and protein level. Structural analysis of kinase proteins domains as defined in multiple sources together with transmembrane alpha helices and signal peptide prediction provides hints to function assignment. The results of the human kinome analysis are collected in the KinWeb database, available for browsing and searching over the internet, where all results from the comparative analysis and the gene structure annotation are made available, alongside the domain information. Kinases may be searched by domain combinations and the relative genes may be viewed in a graphic browser at various level of magnification up to gene organization on the full chromosome set.

Algorithms↗

DG-CST (Disease Gene Conserved Sequence Tags), a database of human-mouse conserved elements associated to disease genes.

The identification and study of evolutionarily conserved genomic sequences that surround disease-related genes is a valuable tool to gain insight into the functional role of these genes and to better elucidate the pathogenetic mechanisms of disease. We created the DG-CST (Disease Gene Conserved Sequence Tags) database for the identification and detailed annotation of human-mouse conserved genomic sequences that are localized within or in the vicinity of human disease-related genes. CSTs are defined as sequences that show at least 70% identity between human and mouse over a length of at least 100 bp. The database contains CST data relative to over 1088 genes responsible for monogenetic human genetic diseases or involved in the susceptibility to multifactorial/polygenic diseases. DG-CST is accessible via the internet at http://dgcst.ceinge.unina.it/ and may be searched using both simple and complex queries. A graphic browser allows direct visualization of the CSTs and related annotations within the context of the relative gene and its transcripts.

Animals↗

Enterobacterial repetitive intergenic consensus sequence repeats in yersiniae: genomic organization and functional properties.

Genome-wide analyses carried out in silico revealed that the DNA repeats called enterobacterial repetitive intergenic consensus sequences (ERICs), which are present in several Enterobacteriaceae, are overrepresented in yersiniae. From the alignment of DNA regions from the wholly sequenced Yersinia enterocolitica 8081 and Yersinia pestis CO92 strains, we could establish that ERICs are miniature mobile elements whose insertion leads to duplication of the dinucleotide TA. ERICs feature long terminal inverted repeats (TIRs) and can fold as RNA into hairpin structures. The proximity to coding regions suggests that most Y. enterocolitica ERICs are cotranscribed with flanking genes. Elements which either overlap or are located next to stop codons are preferentially inserted in the same (or B) orientation. In contrast, ERICs located far apart from open reading frames are inserted in the opposite (or A) orientation. The expression of genes cotranscribed with A- and B-oriented ERICs has been monitored in vivo. In mRNAs spanning B-oriented ERICs, upstream gene transcripts accumulated at lower levels than downstream gene transcripts. This difference was abolished by treating cells with chloramphenicol. We hypothesize that folding of B-oriented elements is impeded by translating ribosomes. Consequently, upstream RNA degradation is triggered by the unmasking of a site for the RNase E located in the right-hand TIR of ERIC. A-oriented ERICs may act in contrast as upstream RNA stabilizers or may have other functions. The hypothesis that ERICs act as regulatory RNA elements is supported by analyses carried out in Yersinia strains which either lack ERIC sequences or carry alternatively oriented ERICs at specific loci.

Base Sequence↗