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1. Determinants of vector-borne avian pathogen occurrence in a mosaic of habitat fragmentation in California

   https://doi.org/10.1186/s13071-025-06742-x  

   Amaya-Mejia, Wilmer; Pavan, Lucas; Lilly, Marie; Swei, Andrea; Dirzo, Rodolfo; Sehgal, Ravinder_N M (December 2025, Parasites & Vectors)

   Abstract BackgroundAs habitat fragmentation increases, ecological processes, including patterns of vector-borne pathogen prevalence, will likely be disrupted, but ongoing investigations are necessary to examine this relationship. Here, we report the differences in the prevalence of Lyme disease (Borrelia burgdorferisensu lato, s.l.) and haemoproteosis (Haemoproteusspp.) pathogens in avian populations of a fragmented habitat.B. burgdorferis.l. is a generalist pathogen that is transmitted byIxodes pacificusvectors in California, andHaemoproteusis an avian parasite transmitted byCulicoidesvectors. MethodsTo determine whether biotic (avian and mammalian abundance) or abiotic characteristics (patch size and water availability) correlated with infection prevalence change, we screened 176 birds sampled across seven sites in oak woodland habitat in northern California. ResultsWhile biotic factors correlated with an increase in both pathogens, infection prevalence ofHaemoproteusspp. was only associated with individual-level traits, specifically foraging substrate and diet, andB. burgdorferis.l. was associated with community-level characteristics, both total mammal and, specifically, rodent abundance. Proximity to water was the only abiotic factor found to be significant for both pathogens and reinforces the importance of water availability for transmission cycles. Larger patch sizes did not significantly affect infection prevalence ofHaemoproteus,but did increase the prevalence ofB. burgdorferi. ConclusionsThese results highlight that while environmental factors (specifically habitat fragmentation) have a limited role in vector-borne pathogen prevalence, the indirect impact to biotic factors (community composition) can have consequences for bothHaemoproteusandB. burgdorferiprevalence in birds. Given the pervasiveness of habitat fragmentation, our results are of broad significance. Graphical abstract 

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2. Regional Differences in Young’s Modulus of the Porcine Lens Capsule

   https://doi.org/10.1007/s10439-026-04012-0  

   Jang, Hoyeon; Cline, Myles; Lee, Jeongjin; Reilly, Matthew; Cho, Hanna (January 2026, Annals of Biomedical Engineering)

   Abstract PurposeThe ocular lens capsule is a biomechanically specialized basement membrane essential for lens function, yet its regional micromechanical properties remain incompletely characterized. MethodsWe employed atomic force microscopy (AFM)-based force spectroscopy to map the stiffness of young porcine anterior and posterior lens capsule samples under physiologically hydrated conditions. A refined dissection protocol was used to preserve native curvature and hydration, with the anterior and posterior regions isolated via selective capsular puncture. Force–indentation measurements were performed using calibrated silicon cantilevers and analyzed with the Johnson–Kendall–Roberts (JKR) model to extract local Young’s modulus. ResultsResults from over 12,000 force curves revealed that the anterior capsule exhibited significantly higher stiffness (mean 67.9 kPa, standard deviation 40.1 kPa) than the posterior (mean 54.1 kPa, standard deviation 25.2 kPa;p < 0.0001), with a wider range of stiffness values. AFM topography confirmed comparable surface morphology, ruling out roughness as a confounding factor. ConclusionThese findings highlight the functional specialization of the lens capsule and the utility of AFM for high-resolution biomechanical characterization. These measurement techniques will be applied to human lens capsules to elucidate age-related changes in capsule properties pertaining to presbyopia, inform surgical strategies, lens capsule modeling, and the design of accommodative intraocular lenses. 

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3. Beyond bacterial paradigms: uncovering the functional significance and first biogenesis machinery of archaeal lipoproteins

   https://doi.org/10.1101/2024.08.27.609747  

   Hong, Yirui; Makarova, Kira S; Xu, Rachel; Pfeiffer, Friedhelm; Pohlschroder, Mechthild (August 2024, bioRxiv)

   Abstract Lipoproteins are major constituents of prokaryotic cell surfaces. In bacteria, lipoprotein attachment to membrane lipids is catalyzed by prolipoprotein diacylglyceryl transferase (Lgt). However, no Lgt homologs have been identified in archaea, suggesting the unique archaeal membrane lipids require distinct enzymes for lipoprotein lipidation. Here, we performedin silicopredictions for all major archaeal lineages and revealed a high prevalence of lipoproteins across the domain Archaea. Using comparative genomics, we identified the first set of candidates for archaeal lipoprotein biogenesis components (Ali). Genetic and biochemical characterization confirmed two paralogous genes,aliAandaliB, are important for lipoprotein lipidation in the archaeonHaloferax volcanii. Disruption of AliA- and AliB-mediated lipoprotein lipidation results in severe growth defects, decreased motility, and cell-shape alterations, underscoring the importance of lipoproteins in archaeal cell physiology. AliA and AliB also exhibit different enzymatic activities, including potential substrate selectivity, uncovering a new layer of regulation for prokaryotic lipoprotein lipidation. 

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4. Congeneric Rodents Differ in Immune Gene Expression: Implications for Host Competence for Tick‐Borne Pathogens

   https://doi.org/10.1002/jez.2908  

   Assis, Vania R; Cifarelli, Gabriella; Brehm, Allison M; Orrock, John L; Martin, Lynn B (May 2025, Journal of Experimental Zoology Part A: Ecological and Integrative Physiology)

   ABSTRACT Mice in the genusPeromyscusare abundant and geographically widespread in North America, serving as reservoirs for zoonotic pathogens, includingBorrelia burgdorferi(B. burgdorferi), the causative agent of Lyme disease, transmitted byIxodes scapularisticks. While the white‐footed mouse (Peromyscus leucopus(P. leucopus)) is the primary reservoir in the United States, the deer mouse (P. maniculatus), an ecologically similar congener, rarely transmits the pathogen to biting ticks. Understanding the factors that allow these similar species to serve as a poor and competent reservoir is critical for understanding tick‐borne disease ecology and epidemiology, especially as climate change expands the habitats where ticks can transmit pathogens. Our study investigated immunological differences between these rodent species. Specifically, we compared the expression of six immune genes (i.e., TLR‐2, IFN‐γ, IL‐6, IL‐10, GATA‐3, TGF‐β) broadly involved in bacterial recognition, elimination, and/or pathology mitigation in ear biopsies collected by the National Ecological Observatory Network (NEON) as part of their routine surveillance. A principal components analysis indicated that immune gene expression in both species varied in two dimensions: TLR2, IFN‐γ, IL‐6, and IL‐10 (comprising PC1) and TGF‐β and GATA3 (comprising PC2) expression tended to covary within individuals. However, when we analyzed expression differences of each gene singly between species,P. maniculatusexpressed more TLR2, IL‐6, and IL‐10 but less IFN‐γ and GATA3 thanP. leucopus. This immune profile could partly explain whyP. leucopusis a better reservoir for bacterial pathogens such asB. burgdorferi. 

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5. Organization and replicon interactions within the highly segmented genome of Borrelia burgdorferi

   https://doi.org/10.1371/journal.pgen.1010857  

   Ren, Zhongqing; Takacs, Constantin N.; Brandão, Hugo B.; Jacobs-Wagner, Christine; Wang, Xindan (July 2023, PLOS Genetics)

   Boccard, Frederic (Ed.)

   Borrelia burgdorferi, a causative agent of Lyme disease, contains the most segmented bacterial genome known to date, with one linear chromosome and over twenty plasmids. How this unusually complex genome is organized, and whether and how the different replicons interact are unclear. We recently demonstrated thatB.burgdorferiis polyploid and that the copies of the chromosome and plasmids are regularly spaced in each cell, which is critical for faithful segregation of the genome to daughter cells. Regular spacing of the chromosome is controlled by two separate partitioning systems that involve the protein pairs ParA/ParZ and ParB/Smc. Here, using chromosome conformation capture (Hi-C), we characterized the organization of theB.burgdorferigenome and the interactions between the replicons. We uncovered that although the linear chromosome lacks contacts between the two replication arms, the two telomeres are in frequent contact. Moreover, several plasmids specifically interact with the chromosomeoriCregion, and a subset of plasmids interact with each other more than with others. We found that Smc and the Smc-like MksB protein mediate long-range interactions on the chromosome, but they minimally affect plasmid-chromosome or plasmid-plasmid interactions. Finally, we found that disruption of the two partition systems leads to chromosome restructuring, correlating with the mis-positioning of chromosomeoriC. Altogether, this study revealed the conformation of a complex genome and analyzed the contribution of the partition systems and SMC family proteins to this organization. This work expands the understanding of the organization and maintenance of multipartite bacterial genomes. 

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