Biology subjects

Straub, C.

Publications and source records attributed to Straub, C..

7 recordsLinked to original sources

bioRxiv2023

Rapid dissemination of host-metabolism-manipulating transposon-like entities via integrative and conjugative elements

Integrative and conjugative elements (ICEs) are self-transmissible mobile elements that transfer functional genetic units across broad phylogenetic distances. Accessory genes shuttled by ICEs can make significant contributions to bacterial fitness, yet ICEs that carry accessory genes encoding functions other than antimicrobial resistance remain poorly characterized. Recent observation of the rapid acquisition of ICEs in a pandemic lineage of Pseudomonas syringae pv. actinidae led to investigation of the structural and functional diversity of these elements among a diverse array of P. syringae. Fifty-three unique ICE types were identified across multiple phylogroups. These ICEs display distinct evolutionary histories compared to their bacterial hosts, are highly recombinogenic, exhibit a conserved structure and are punctuated by hotspots of accessory gene integration. Many carry a 16 kb transposon-like entity (Tn6212) that shows little polymorphism indicating recent dissemination. Deletion of Tn6212 did not alter pathogen growth in planta, but mutants displayed significant fitness defects when grown on TCA cycle intermediates. These were largely attributable to a single LysR regulator. RNA-seq analysis of a set of nested Tn6212 deletions confirmed a central role of LysR in enhanced expression of more than 300 genes and down-regulation of genes controlling expression of energetically demanding loci. Together the transcriptional data indicate a major role for Tn6212 in manipulation of bacterial metabolism with primary effects on RNA degradation, protein synthesis and potential diversion of ATP to growth.

microbiology↗

bioRxiv2022

Lung spatial profiling reveals a T cell signature in COPD patients with fatal SARS-CoV-2 infection

RationalePeople with pre-existing lung diseases like chronic obstructive pulmonary disease (COPD) are more likely to get very sick from SARS-CoV-2 disease 2019 (COVID-19), but an interrogation of the immune response to COVID-19 infection, spatial throughout the lung structure is lacking in patients with COPD. ObjectivesTo profile the immune microenvironment of lung parenchyma, airways, and vessels of never- and ever-smokers with or without COPD, whom all died of COVID-19, using spatial transcriptomic and proteomic profiling. FindingsThe parenchyma, airways, and vessels of COPD patients, compared to control lungs had: 1) significant enrichment for lung resident CD45RO+ memory T cells; 2) downregulation of genes associated with T cell antigen-priming and memory T cell differentiation; 3) higher expression of proteins associated with SARS-CoV-2 entry and major receptor ubiquitously across the ROIs and in particular the lung parenchyma, despite similar SARS-CoV-2 structural gene expression levels. ConclusionsThe lung parenchyma, airways, and vessels of COPD patients have increased T-lymphocytes with a blunted memory T cell response and a more invasive SARS-CoV-2 infection pattern, and may underlie the higher death toll observed with COVID-19.

immunology↗

bioRxiv2021

The Human Tumor Atlas Network (HTAN) Breast PreCancer Atlas: A multi-omic integrative analysis of ductal carcinoma in situ with clinical outcomes

Ductal carcinoma in situ (DCIS) is the most common precursor of invasive breast cancer (IBC), with variable propensity for progression. We have performed the first multiscale, integrated profiling of DCIS with clinical outcomes by analyzing 677 DCIS samples from 481 patients with 7.1 years median follow-up from the Translational Breast Cancer Research Consortium (TBCRC) 038 study and the Resource of Archival Breast Tissue (RAHBT) cohorts. We identified 812 genes associated with ipsilateral recurrence within 5 years from treatment and developed a classifier that was predictive of DCIS or IBC recurrence in both cohorts. Pathways associated with recurrence include proliferation, immune response, and metabolism. Distinct stromal expression patterns and immune cell compositions were identified. Our multiscale approach employed in situ methods to generate a spatially resolved atlas of breast precancers, where complementary modalities can be directly compared and correlated with conventional pathology findings, disease states, and clinical outcome. HIGHLIGHTS Development of a new classifier for DCIS recurrence or progression Outcome associated pathways identified across multiple data types and compartments Four stroma-specific signatures identified CNAs characterize DCIS subgroups associated with high risk invasive cancers

cancer biology↗

bioRxiv2019

Population imaging of neural activity in awake behaving mice in multiple brain regions

A longstanding goal in neuroscience has been to image membrane voltage, with high temporal precision and sensitivity, in awake behaving mammals. Here, we report a genetically encoded voltage indicator, SomArchon, which exhibits millisecond response times and compatibility with optogenetic control, and which increases the sensitivity, signal-to-noise ratio, and number of neurons observable, by manyfold over previous reagents. SomArchon only requires conventional one-photon microscopy to achieve these high performance characteristics. These improvements enable population analysis of neural activity, both at the subthreshold and spiking levels, in multiple brain regions - cortex, hippocampus, and striatum - of awake behaving mice. Using SomArchon, we detect both positive and negative responses of striatal neurons during movement, highlighting the power of voltage imaging to reveal bidirectional modulation. We also examine how the intracellular subthreshold theta oscillations of hippocampal neurons govern spike output, finding that nearby cells can exhibit highly correlated subthreshold activities, even as they generate highly divergent spiking patterns.

neuroscience↗

bioRxiv2018

Distinct Cortical-Thalamic-Striatal Circuits Through the Parafascicular Nucleus

The thalamic parafascicular nucleus (PF), an excitatory input to the basal ganglia, is targeted with deep-brain-stimulation to alleviate a range of neuropsychiatric symptoms. Furthermore, PF lesions disrupt the execution of correct motor actions in uncertain environments. Nevertheless, the circuitry of the PF and its contribution to action selection are poorly understood. We find that, in mice, PF forms the densest subcortical projection to the striatum. This projection arises from transcriptionally- and physiologically-distinct classes of PF neurons that are also reciprocally connected with functionally-distinct cortical regions, differentially innervate striatum neurons, and are not synaptically connected in PF. Thus, mouse PF contains heterogeneous neurons that are organized into parallel and independent associative, limbic, and motor circuits. Furthermore, these subcircuits share motifs of cortical-PF-cortical and cortical-PF-striatum organization that allow each PF subregion, via its precise connectivity with cortex, to coordinate diverse inputs to striatum.

neuroscience↗

bioRxiv2017

The ecological genetics of Pseudomonas syringae residing on the kiwifruit leaf surface

Interactions between commensal microbes and invading pathogens are understudied, despite their likely effects on pathogen population structure and infection processes. We describe the population structure and genetic diversity of a broad range of co-occurring Pseudomonas syringae isolated from infected and uninfected kiwifruit during an outbreak of bleeding canker disease caused by P. syringae pv. actinidiae (Psa) in New Zealand. Overall population structure was clonal and affected by ecological factors including infection status and cultivar. Most isolates are members of a new clade in phylogroup 3 (PG3a), also present on kiwifruit leaves in China and Japan. Stability of the polymorphism between pathogenic Psa and commensal P. syringae PG3a isolated from the same leaf was tested using reciprocal invasion from rare assays in vitro and in planta. P. syringae G33C (PG3a) inhibited Psa NZ54, while the presence of Psa NZ54 enhanced the growth of P. syringae G33C. This effect could not be attributed to virulence activity encoded by the Type 3 secretion system of Psa. Together our data contribute toward the development of an ecological perspective on the genetic structure of pathogen populations.\n\nORIGINALITY-SIGNIFICANT STATEMENTBacterial pathogen populations are often studied with little consideration of co-occurring microbes and yet interactions between pathogens and commensals can affect both population structure and disease progression. A fine-scale sampling of commensals present on kiwifruit leaves during an outbreak of bleeding canker disease caused by P. syringae pv. actinidiae reveals a clonal population structure. A new clade of non-pathogenic P. syringae (PG3a) appears to be associated with kiwifruit on a global scale. The presence of PG3a on kiwifruit has significant effects on the outcome of infection by P. syringae pv. actinidiae. This emphasises the value of studying the effect of co-occurring bacteria on pathogen-plant interactions.

microbiology↗

bioRxiv2016

The origin and evolution of a pandemic lineage of the kiwifruit pathogen Pseudomonas syringae pv. actinidiae

Recurring epidemics of kiwifruit (Actinidia spp.) bleeding canker disease are caused by Pseudomonas syringae pv. actinidiae (Psa), whose emergence coincided with domestication of its host. The most recent pandemic has had a deleterious effect on kiwifruit production worldwide. In order to strengthen understanding of population structure, phylogeography and evolutionary dynamics of Psa, we sampled 746 Pseudomonas isolates from cultivated and wild kiwifruit across six provinces in China, of which 87 were Psa. Of 234 Pseudomonas isolated from wild Actinidia spp. none were identified as Psa. Genome sequencing of fifty isolates and the inclusion of an additional thirty from previous studies show that China is the origin of the recently emerged pandemic lineage. However China harbours only a fraction of global Psa diversity, with greatest diversity found in Korea and Japan. Distinct transmission events were responsible for introduction of the pandemic lineage of Psa into New Zealand, Chile and Europe. Two independent transmission events occurred between China and Korea, and two Japanese isolates from 2014 cluster with New Zealand Psa. Despite high similarity at the level of the core genome and negligible impact of within-lineage recombination, there has been substantial gene gain and loss even within the single clade from which the global pandemic arose.\n\nSIGNIFICANCE STATEMENTBleeding canker disease of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) has come to prominence in the last three decades. Emergence has coincided with domestication of the host plant and provides a rare opportunity to understand ecological and genetic factors affecting the evolutionary origins of Psa. Here, based on genomic analysis of an extensive set of strains sampled from China and augmented by isolates from a global sample, we show, contrary to earlier predictions, that China is not the native home of the pathogen, but is nonetheless the source of the recent global pandemic. Our data identify specific transmission events, substantial genetic diversity and point to non-agricultural plants in either Japan or Korea as home to the source population.

epidemiology↗