Brian Stevenson Ph.D. spirochete lab
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bstevensonlab.bsky.social
Brian Stevenson Ph.D. spirochete lab
@bstevensonlab.bsky.social
3.1K followers 2.1K following 800 posts
Mostly about bacterial gene/protein regulation & function, esp. with Borrelia burgdorferi and Lyme disease. Professor at U Kentucky, views are my own. He/him
Lab= http://microscopist.net/Stevenson_Lab.html
UK= https://medicine.uky.edu/users/bstev0
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bstevensonlab.bsky.social
Leptospira interrogans produces effectors, structurally related to toxin-like proteins, that modulate calcium homeostasis and disrupt cell-cell junctions, thereby allowing translocation across epithelium barriers, tissue colonization and pathogenicity.

pubmed.ncbi.nlm.nih.gov/41634022/

#MicroSky
From the paper: Figure 10. Proposed model of VM protein-mediated disruption of cell-cell junctions. In non-infected cells (on the left), tight junctions (JAM, Occludin and Claudin) and adherens junctions (Cadherin) stabilize cell-cell junctions while ZO/Cadherin proteins connect junctions and actin cytoskeleton. During leptospiral infection (on the right), L. interrogans induces the expression and secretion of two virulence-modifying (VM) proteins, LIMLP_11655 and LIMLP_11660. These proteins would interact directly with host epithelial cells, very likely by binding of their Ricin B domain to lectin receptors present at the host cell surface. The VMs could be then internalized within the host cell, where they trigger an increase in intracellular calcium levels. This calcium deregulation would activate the calmodulin-MLCK pathway, leading to actin cytoskeleton remodeling and ultimately disassembly of tight and adherens junctions. The resulting loss of barrier integrity facilitates L. interrogans transmigration across epithelial and endothelial cell layers, promoting systemic dissemination to target organs, such as liver and kidneys.
February 4, 2026 at 3:43 PM
bstevensonlab.bsky.social
A 5500-year-old Treponema pallidum genome from Sabana de Bogotá, Colombia

"This genome falls outside of known T. pallidum lineages today, but it has many genetic hallmarks associated with virulence in modern pathogens of these subspecies"

Science
pubmed.ncbi.nlm.nih.gov/41570125/

#MicroSky
From the paper: Deeply divergent Treponema pallidum lineage in the Americas and implications for pathogen evolution. We identified and reconstructed a ~5500-year-old 1.7× T. pallidum genome (TE1-3) from a Middle Holocene individual at Tequendama I rock shelter in Colombia. Phylogenomic analysis reveals that TE1-3 is an early-branching sister lineage to all extant T. pallidum subspecies, with divergence dating to ~13,700 years ago (95% HPD: 6768 to 20,592 cal yr B.P.) and coinciding with early human migration and ecological shifts in the Americas. Despite its antiquity, TE1-3 possesses the T. pallidum virulence-associated genes, suggesting conserved pathogenic capacity. TE1-3 provides the earliest molecular evidence of T. pallidum in the Americas to date, bridging a multimillennial gap between skeletal signs and genomic data and offering a rare glimpse into the long-term evolution of treponemal pathogens.
February 3, 2026 at 5:21 PM
bstevensonlab.bsky.social
On restriction systems among Lyme spirochetes:

"Comparative analysis of Borrelia's Defence mechanisms and their impact on genetic manipulation of low-passage isolates of Borrelia afzelii and Borrelia garinii"

by Ruivo and colleagues
pubmed.ncbi.nlm.nih.gov/41551585/

#Microsky
Graphical abstract of Ruivo et al
February 2, 2026 at 3:01 PM
bstevensonlab.bsky.social
The Originals.
Attendees of last weeks Spirochete GRC who were also at the first edition in 1994 (noting at least 2 people who missed the photo)
@wolfzueckert.bsky.social
@therealjskare.bsky.social
Attendees of the first Biology of Spirochetes GRC in 1994, who were also at the recent conference
January 29, 2026 at 5:58 PM
bstevensonlab.bsky.social
2026 Biology of Spirochetes Gordon Conference wrapped up. Photo of the 4 of us who have attended every Spirochete GRC, which began in 1994. A long, strange trip so far, and may we continue to solve many more mysteries!
Scott, Jon, me, and Wolf
@therealjskare.bsky.social
@wolfzueckert.bsky.social
The four who have participated in every Biology of Spirochetes Gordon Conference, which began in 1994
January 23, 2026 at 5:19 PM
bstevensonlab.bsky.social
Looking forward to seeing good friends and colleagues at the Biology of Spiochetes Gordon Conference, beginning this Sunday!
Sadly, not on the beach in Ventura, but inland in Pomona, California

www.grc.org/biology-of-s...

#MicroSky
“Giant beach spirochete” in California Actually, a bit of sea weed
January 16, 2026 at 3:10 PM
bstevensonlab.bsky.social
Huxley had amazingly long and thick muttonchops!
There’s your New Year challenge!!
Thomas Henry Huxley
December 25, 2025 at 4:35 PM
bstevensonlab.bsky.social
A great beard on a scientist
December 25, 2025 at 4:05 PM
bstevensonlab.bsky.social
Happy Holidays to all !

(Image source not known)
Picture of a hippopotamus Caption says: I am not a toy. I am not a Christmas present. I am a 3000 pound, semi-aquatic liability. Please think hard before gifting a hippopotamus this Christmas.
December 25, 2025 at 12:40 AM
bstevensonlab.bsky.social
Using citizen science to describe the prevalence and distribution of tick bite and exposure to tick-borne diseases in the United States

One of Nate Nieto's hallmark publications,

PLoS One, 2018 Jul 12;13(7):e0199644.
doi: 10.1371/journal.pone.0199644
pubmed.ncbi.nlm.nih.gov/30001350/
Figure 1 from the paper: Submissions to the free tick testing program from across the US (A), starting in January 2017 ending in August of 2017 (B).
December 24, 2025 at 3:28 PM
bstevensonlab.bsky.social
Recent news brings back memories of friend and colleague Nate Nieto, who died of pancreatic cancer at the age of 44, in 2019. This disease has cut short many lives.
Nate was well known in the tick-borne disease community, particularly for his “citizen science” approaches.
#MicroSky
#TickSky
Cartoon of a punk-haired tick riding a boogie board on a wave. From a t-shirt sold to raise funds after Nate Nieto’s death
December 24, 2025 at 3:23 PM
bstevensonlab.bsky.social
Another grant celebration bottle added to the collection
Collection of champagne bottles, each representing a newly funded grant
December 18, 2025 at 4:16 PM
bstevensonlab.bsky.social
"We cannot address TB only with vaccines and medications... We must also address the root cause of tuberculosis, which is injustice. In a world where everyone can eat, and access healthcare, and be treated humanely, tuberculosis has no chance. Ultimately, we are the cause. We must also be the cure."
Cover of "Everything is Tuberculosis", by John Green
December 6, 2025 at 3:37 PM
bstevensonlab.bsky.social
"tick bites and tick saliva reprogram Langerhans cells, (which) dampens protective immunity and helps explain how ticks and their pathogens evade host defense and achieve efficient transmission"

www.nature.com/articles/s41...

#MicroSky
Graphical abstract for the paper. Tick feeding causes the up-regulation of CCR7 and CXCR4 on human epidermal LCs, which are polarized by tick saliva and emigrate to the lymphatics to mediate immune tolerance. Consequently, tolerogenic T cell priming and lack of effector T cell differentiation results in an inappropriate T cell response to tick-borne pathogens.
December 1, 2025 at 4:49 PM
bstevensonlab.bsky.social
Identification of Previously Unknown DNA-Binding Proteins Using DNA Affinity/Pull-Down Methods Followed by Mass Spectrometry

Jutras, Babb, Jusufovic, Krusenstjerna, Saylor, Verma, and Stevenson

Current Protocols 2025, 5:e70264
doi: 10.1002/cpz1.70264

#MicroSky
Schematic overview of the process of DNA-affinity / pull down identification of unknown nucleic acid-binding proteins
November 26, 2025 at 4:00 PM
bstevensonlab.bsky.social
My Granddad, William Robert Fleming Stevenson, received these medals (and shrapnel in his knee) for 4 years in the European trenches, fighting The War to End All Wars.
#VeteransDay
#RemembranceDay
World War 1 medals superimposed over a field of red poppies
November 11, 2025 at 12:09 PM
bstevensonlab.bsky.social
The answer may not be at the bottom of a margarita glass, but we should at least check
November 7, 2025 at 10:26 PM
bstevensonlab.bsky.social
Gac Is a Transcriptional Repressor of the Lyme Disease Spirochete's OspC Virulence-Associated Surface Protein

Castro-Padovani, Saylor, Husted, Krusenstjerna, Jusufovic, and Stevenson
2023, J Bacteriol, 205:e0044022.
doi: 10.1128/jb.00440-22
pubmed.ncbi.nlm.nih.gov/36920207/
#MicroSky
(A) Electrophoretic mobility shift assay (EMSA) of labeled Ip89 ospC operator, without (−) and with (+) cytoplasmic extract from strain B31. The asterisk indicates shifted probe that was present only when borrelial extract was included, indicating presence of a DNA-binding component. Unbound DNA is indicated by “free.” Some labeled DNA probe remained in the wells of the gel. (B) Cytoplasmic extract from strain B31 was incubated with Ip89 ospC operator DNA affixed to beads, eluted with increasing concentrations of NaCl, and eluates were separated by SDS-polyacrylamide gel electrophoresis. Lanes are labeled with the concentration of NaCl used for that elution. The arrow indicated a protein band of 30 to 35 kDa that eluted in the 0.3 and 0.5 mM NaCl washes. (C) Amino acid sequence of GyrA and Gac (the two potential initiation methionines of Gac are indicated by boldface and underlining). Mass spectrometry identified nine unique peptides that all mapped to the Gac ORF. Peptides identified with high confidence are shaded green, and those with lower confidence are red. (D) Predicted structures of B. burgdorferi Gac and GyrA proteins, as determined by AlphaFold (https://alphafold.ebi.ac.uk). Both are consistent with the solved structures of B. burgdorferi Gac and the N-terminal domain of E. coli GyrA (https://www.rcsb.org/structure/4ckk).
November 7, 2025 at 3:51 PM
bstevensonlab.bsky.social
Quantitative analyses of interactions between SpoVG and RNA/DNA
Saylor et al, 2023, Biochem Biophys Res Commun, 30:654:40-46.
doi: 10.1016/j.bbrc.2023.02.044
pubmed.ncbi.nlm.nih.gov/36889033/
#MicroSky
Ribbon diagram of SpoVG dimer structure
November 7, 2025 at 3:47 PM
bstevensonlab.bsky.social
Congratulations to Tim Saylor for successfully defending his MS thesis!
After my trainees complete their defense, I give them a custom-engraved julep cup, then we share a drink together 🥃
Recent graduate with pewter julep cup
November 7, 2025 at 3:42 PM
bstevensonlab.bsky.social
On interactions between Midichloria and Borrelia in Ixodes ricinus ticks: a multifaceted phenomenon likely driven by molecular mechanisms that regulate tick feeding, modulate host immunity, and provide nutritional support.

www.clinicalkey.com#!/content/pl...

#MicroSky
#TickSky
Figure from article: An overview of the shikimate pathway and genomic distribution of genes encoding enzymes required for chorismate biosynthesis among vertically and horizontally transmitted tick-associated symbionts and pathogens. The shikimate pathway comprises seven enzymatic reactions that convert PEP and E4P into chorismate, a key metabolic intermediate that serves as the precursor for the aromatic amino acids tryptophan, tyrosine, and phenylalanine. This pathway is found in various bacteria, archaea, fungi, algae, protozoans, and plants, but is absent in animals. Genes encoding the enzymes required for chorismate biosynthesis are indicated in brackets in the left panel. Among vertically and horizontally transmitted bacteria associated with ticks, only the genomes of Coxiella and Francisella endosymbionts contain a complete or nearly complete set of shikimate pathway genes necessary for chorismate production. Whole-genome sequences of the most important symbiotic and pathogenic bacteria associated with ticks were retrieved from the NCBI database i and included in the analysis. Abbreviations: CS, chorismate synthase; DAHP, 3-deoxy-D-arabino-heptulosonate-7-phosphate; DAHPS, DAHP synthase; DHQD, 3-dehydroquinate dehydratase; DHQS, 3-dehydroquinate synthase; E4P, erythrose-4-phosphate; EPSP, 5-enolpyruvylshikimate-3-phosphate; EPSPS, EPSP synthase; LB, Lyme borreliosis; PEP, phosphoenolpyruvate; RF, relapsing fever; SDH, shikimate dehydrogenase; SK, shikimate kinase.
October 31, 2025 at 6:48 PM
bstevensonlab.bsky.social
For those who are wondering about grant proposal reviews in the USA
Dear NIH Peer Reviewer, You are receiving this email because you are listed on an NIH peer-review meeting roster scheduled to begin in the coming weeks. As you surely know, NIH has not been appropriated funds with which to operate. SROs cannot work, cannot prepare for meetings, respond to your emails, etc. However, the NIH computer systems that support review functions are still available to reviewers (though without technical support) and we ask that you continue your preparations for upcoming review meetings as best you can. If it becomes clear that your meeting must be postponed, you will receive an email to that effect. Please do not join any meeting if it is scheduled to start on a day when the government is shutdown. After funding is appropriated and NIH operations resume, we will be in touch. CSR will make every effort to review all applications originally slated to be reviewed this round. Thank you for your contributions to the NIH peer review process. Regards,
October 21, 2025 at 12:27 PM
bstevensonlab.bsky.social
We were visited a couple of weeks ago by Dr. Tomasz Bykowski and his family, on vacation around the US from their home in Warsaw, Poland.
Tomek was a postdoc in our lab from 2004-2007, and is currently Director of Strategy and Development of Horus and Member of the Supervisory Board of Genomed SA
Brian Stevenson and Tomasz Bykowski
October 14, 2025 at 4:32 PM
bstevensonlab.bsky.social
Lab alumna Dr. Jen Miller, presenting today at ILADS conference. Jen is currently Vice President of Clinical and Scientific Operations at Galaxy Diagnostics. She was my second PhD student.
Photograph of projector screen, showing photograph of Dr Jen Miller and title of her talk: "Survival of the fittest - how vector-borne pathogens evade teh immune system (and what to do about it)"
October 13, 2025 at 1:57 PM
bstevensonlab.bsky.social
On the way to Midwest Microbial Pathogenesis Conference 2025, in St Charles, Illinois!
Hosted by Loyola University Chicago
#MMPC2025
#MicroSky

www.mmpconference2025.com
Announcing MMPC 2025
October 3, 2025 at 4:01 PM