NLM DIR Seminar Schedule
UPCOMING SEMINARS
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May 12, 2026 John Bridgers
A bi-partition function algorithm to evaluate inferred subclonal structures in single-cell sequencing data -
May 14, 2026 Brandon Colelough
TBD -
May 19, 2026 Leann Lindsey
Are Genomic Language Models Learning? Insights from Tokenization Analysis and Prophage Detection in Bacterial Genomes -
May 26, 2026 Harutyun Saakyan
TBD -
May 27, 2026 Brian Abraham
Cis-Regulatory Organization and Transcription Factor Control of Cell Identity and Disease
RECENT SEMINARS
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May 5, 2026 Benjamin Hou
Machine Learning for Craniofacial Malocclusion Prediction -
April 28, 2026 Niccolo Marini
From Unimodal Datasets to Multimodal Foundation Models: Synthetic Clinical Notes for Dermatology AI -
April 21, 2026 Yoshitaka Inoue
Drug Response Prediction: Generalization using Graph Neural Networks & Reasoning over Predictions using LLMs -
April 16, 2026 Matthew Diller
Analyzing Similarity in Common Data Elements in the NIH CDE Repository via Semantic Clustering -
April 7, 2026 Henry Secaira Morocho
Toward a systematic method of database enrichment for reference-based metagenomics
Scheduled Seminars on March 3, 2026
In-person: Building 38A/B2N14 NCBI Library or Meeting Link
Contact NLMDIRSeminarScheduling@mail.nih.gov with questions about this seminar.
Abstract:
Bacterial warfare is a widespread phenomenon in which bacteria deploy toxins to inhibit or kill competitors. These toxins disrupt essential cellular processes, and their diversification is driven by an evolutionary arms race involving toxin and immunity gene acquisition. Here, we used in silico approaches to analyze genomes from the 10kSalmonella Project and identify effectors secreted via the Type VI Secretion System (T6SS). We uncovered 128 candidates distributed across diverse Salmonella serovars and other bacterial species, including a protein harboring a previously unknown circularly permuted variant of NlpC/P60 clade of the papain-like fold.
Strikingly, conflict-associated versions of the permuted NlpC/P60 scaffold arose at distinct points in its evolutionary history and now function in different biological conflict systems. Here, we investigate two such cases. The first, from Salmonella, acts as a T6SS effector mediating interbacterial competition. The second, identified in Legionella, is associated with the Type IV Secretion System (T4SS) and contributes to virulence in eukaryotic hosts. In both instances, comparative evolutionary analyses strongly implicated lipids as primary targets, and experimental validation by collaborating laboratories respectively confirmed their phospholipase and S-palmitoyl transferase activities. Together, these findings reveal how a conserved catalytic scaffold has been repeatedly repurposed to mediate distinct forms of antagonism, from bacterial competition to host–pathogen interactions