Biology subjects

Maki, S.

Publications and source records attributed to Maki, S..

7 recordsLinked to original sources

bioRxiv2026

Co-circulating TBEV lineages and evidence for vertical transmission in wild bank voles from Poland

Tick-borne encephalitis virus (TBEV) is a zoonotic flavivirus maintained in complex enzootic cycles involving ticks and vertebrate hosts. While vector-mediated transmission has been extensively studied, host-associated mechanisms, including vertical transmission and prolonged viral carriage in natural reservoir populations, remain poorly understood. Here, we investigated TBEV circulation, genetic diversity, and evidence for vertical transmission in bank voles (Clethrionomys glareolus) from a highly endemic region of North-eastern Poland. A total of 258 wild rodents were screened using molecular and serological approaches. TBEV RNA was detected in 14.3% of individuals, whereas seroprevalence was substantially lower (6.6%), revealing limited concordance between viral presence and humoral response under natural conditions. Near-complete genome sequences were obtained from 10 TBEV-positive individuals, representing the first near-complete TBEV genomes generated from wild rodents in Poland. All isolates belonged to the European subtype (TBEV-Eu), and phylogenetic analysis revealed two genetically distinct viral clades co-circulating within a narrow spatiotemporal window. Importantly, TBEV RNA and/or envelope protein were detected in embryos from naturally infected females, providing evidence consistent with vertical transmission in a wild reservoir host. Together, these findings suggest that vertical transmission and complex host infection dynamics may be underappreciated components of TBEV maintenance in natural reservoir populations. Our results highlight the need to integrate vertebrate host dynamics into models of TBEV ecology and support expanded wildlife-based surveillance to better understand and predict zoonotic risk.

microbiology↗

bioRxiv2025

A bright synthetic near-infrared luciferin enhances the capabilities of deep-tissue bioluminescence imaging using firefly luciferases

Synthetic bioluminescence reactions exhibiting near-infrared (NIR)-shifted spectra have been explored to improve deep-tissue imaging through the design of firefly luciferin analogues. Although the NIR bioluminescence reactions improve the tissue penetration of bioluminescence signals from deep tissues, their photon output is markedly lower compared to the natural reaction with D-luciferin and firefly luciferase (Fluc), often by an order of magnitude or more. Consequently, in most instances, the sensitivity of NIR bioluminescence imaging (NIR-BLI) has not yet substantially surpassed that of BLI with the natural firefly reaction. Here, we present a synthetic firefly luciferin, named AkaSuke, that generates intense NIR bioluminescence ({lambda}max = 680 nm) in reaction with Fluc, greatly improving the detection sensitivity beyond that of the D-luciferin/Fluc reaction for targeting deep tissue. AkaSuke enables sensitive visualizations of ectopic hematogenesis through entire tissues of mice over time following transplantation of bone marrow stem cells labeled with Fluc. We additionally identify a Japanese firefly luciferase, DkumLuc1, that displays higher catalytic activities for bioluminescence emission of AkaSuke compared to typical Fluc, resulting in detection sensitivity comparable to that of AkaLumine/Akaluc reaction, one of the most sensitive bioluminescence systems for deep tissue imaging. We further propose the potential of the AkaSuke/DkumLuc1 reaction as an orthogonal pair with the AkaLumine/Akaluc for sensitive dual-target tracking in mice. Overall results suggest that AkaSuke enhances the capabilities of deep-tissue bioluminescence imaging using Fluc and its variant, and could serve as an emerging benchmark for the molecular design of NIR luciferin analogues.

cancer biology↗

bioRxiv2024

Circulating mucosal-like IgA responses associate with severity of Puumala orthohantavirus-caused hemorrhagic fever with renal syndrome

Old World Orthohantaviruses cause hemorhagic fever with renal syndrome (HFRS) characterized by increased vascular permeability and acute kidney injury (AKI). Despite the systemic nature of the disease, the virus enters humans through inhalation and therefore initially encounters the immunoglobulin class A (IgA) dominated mucosal immune system. Herein, we characterized systemic IgA responses and their potential relationship to the mucosal immune activation by examining blood samples obtained from patients hospitalized due to acute Puumala orthohantavirus infection. Our findings reveal increased frequencies of IgA-expressing circulating mucosal-associated B1 cells and plasmablasts, as well as elevated levels of polyreactive, polymeric, virus-specific and secretory IgA in the acute stage of the disease. Importantly, the levels of circulating virus-specific and secretory IgA associated with the severity of AKI. Furthermore, circulating polymeric IgA displayed enhanced effector functions by forming stable complexes with the IgA receptor CD89 and induced pro-inflammatory neutrophil responses. These results suggest that, while an efficient mucosal immune response is likely to be crucial for infection clearance, an excessive mucosal immune activation may contribute to HFRS disease progression.

immunology↗

bioRxiv2024

Neuroestrogens facilitate male-typical behaviors by potentiating androgen receptor signaling in medaka

In rodents, estrogens aromatized from androgens in the brain are essential for the development of male-typical behaviors. In many other vertebrates including humans and teleost fish, however, androgens facilitate these behaviors directly via the androgen receptor without aromatization into estrogens. Here we report that mutagenesis-derived male medaka fish lacking Cyp19a1b (a subtype of aromatase predominantly expressed in the brain) exhibit severely impaired male-typical mating and aggression, despite elevated brain androgen levels. These phenotypes can be rescued by estrogen administration, indicating that brain-derived estrogens are pivotal for male-typical behaviors even in teleosts. Our results further suggest that these estrogens facilitate male-typical behaviors by potentiating androgen action in the brain via the direct stimulation of androgen receptor transcription. Taken together, these findings reveal a previously unappreciated mode of action of brain-derived estrogens in shaping male-typical behaviors.

physiology↗

bioRxiv2022

Wild red deer (Cervus elaphus) do not play a role as vectors or reservoirs of SARS-CoV-2 in north-eastern Poland.

Several studies reported a high prevalence of SARS-CoV-2 among white-tailed deer in North America. Monitoring cervids in all regions to better understand SARS-CoV-2 infection and circulation in other deer populations has been urged. To evaluate deer exposure to SARS-CoV-2 in Poland, we sampled 90 reed deer individuals shot by hunters in five hunting districts in northeastern Poland. Serum and nasopharyngeal swabs were collected, and then the Immunofluorescent Assay (IFA) to detect anti-SARS-CoV-2 antibodies was performed as well as real-time PCR with reverse transcription for direct virus detection. No positive samples were detected. There is no evidence of spillover of SARS-CoV-2 from the human to deer population in Poland.

microbiology↗

bioRxiv2022

Serological surveillance for wild rodent infection with SARS-CoV-2 in Europe

We report serological surveillance for exposure to SARS-CoV-2 in 1,237 wild rodents and other small mammals across Europe. All samples were negative with the possible exception of one. Given the ongoing circulation of this virus in humans and potential host jumps, we suggest such surveillance be continued.

microbiology↗

bioRxiv2020

Zoonotic viruses in three species of voles (Microtus spp.) from Poland

Rodents are known to be reservoir hosts for a plethora of zoonotic viruses and therefore play a significant role in the dissemination of these pathogens. We trapped three vole species (Microtus arvalis, M. oeconomus and M. agrestis) in N.E. Poland, all of which are widely distributed species in Europe, and, using immunofluorescence assays, we assessed serum samples for the presence of antibodies to hantaviruses, arenaviruses and cowpox viruses (CPXV). We detected antibodies against CPXV and Puumala virus (PUUV), overall seroprevalence of combined viral infections of 18.2% [10.5-29.3] and mostly attributed to CPXV. Antibodies to Tula hantavirus, typical for Microtus voles, are known to cross-react strongly with the PUUV antigen used in PUUV screening, but we detected only one PUUV/TULV cross-reaction in Microtus arvalis (1.3% [0.1-7.9]). We found antibodies against CPXV in all three Microtus spp. Seroprevalence was similar in all vole species. There were no significant differences in seroprevalence between the sexes and among host age categories. Our results contribute to the increasing understanding of CPXV abundance in voles in Europe, and confirm that CPXV circulates also in Microtus spp. voles in NE Poland.

microbiology↗