Biology subjects

Maire, T.

Publications and source records attributed to Maire, T..

5 recordsLinked to original sources

bioRxiv2026

Pangenome Analysis Reveals Gene Content Variation and Evolutionary Dynamics Across the Culex pipiens Species Complex

The Culex pipiens species complex contains the principal northern-hemisphere vectors of West Nile virus, lymphatic filariasis and several arboviruses; yet, the genomic basis of its diversity remains poorly resolved. We present the first pangenome characterization of the four widely recognized Cx. pipiens complex forms (Cx. pipiens, Cx. pallens, Cx. quinquefasciatus, Cx. molestus), with Cx. tarsalis as outgroup. From chromosome-scale assemblies (533-790 Mb) and unified annotations transferred from the Cx. quinquefasciatus reference, we identified 16,568 orthogroups. Restricted to the ingroup, 92,821 genes (98.2 %) were partitioned into 11,284 core (71.1 %), 3,726 shell (23.5 %) and 871 cloud (5.5 %) orthogroups. Form-specific cloud orthogroups were unevenly distributed ({chi}{superscript 2} = 71.9, p = 1.7 x 10-{superscript 1}), with Cx. molestus carrying the largest set. A concatenated 8,067-locus phylogeny placed Cx. pallens and Cx. quinquefasciatus as sisters with full bootstrap support but only 58.9 % gene-tree and 45.1 % site concordance at the deep ingroup node, a pattern consistent with prior evidence that Cx. pallens arose through hybridization between Cx. pipiens and Cx. quinquefasciatus. CAFE5 detected 582 gene families with significant rate departures, and inferred expansions outnumbering contractions on every lineage (counts across all orthogroups with an inferred size change; Cx. quinquefasciatus greatest, 3,733 expanded vs. 729 contracted). Whole-genome ANI ranged 93.1-94.7 % (skani); synteny was conserved at the chromosome scale (74-77 % collinear anchors) with 258-294 inversions [≥] 100 kb per pair. Transposable elements occupied a uniform genome fraction (52.7-54.4 %). These results refine the divergence framework for the complex, provide evidence consistent with a hybrid origin of Cx. pallens, and establish a pangenomic baseline for future population-level resequencing. HighlightsO_LIFirst chromosome-scale pangenome of the Culex pipiens species complex. C_LIO_LI16,568 orthogroups partitioned into core, shell and cloud compartments. C_LIO_LIPhylogenomic discordance supports a hybrid origin for Cx. pallens. C_LIO_LICAFE5 reveals strong, lineage-wide gene-family expansion across the complex. C_LIO_LIConserved synteny and [~]53% transposable-element content across all genomes. C_LI

genomics↗

bioRxiv2026

Deep behavioral phenotyping of pathogen infected mosquitoes reveals species-specific behavior changes enhancing transmission

Mosquito-borne pathogens are often proposed to alter mosquito behavior to enhance transmission, yet the prevalence, magnitude, and consequences of such effects remain unclear. Using custom high- throughput behavioral assays and deep-learning analysis, we quantified the blood-feeding behavior of more than 5,000 mosquitoes, and long-term activity patterns of more than 1,000 mosquitoes across six clinically relevant mosquito-pathogen combinations. Infection effects were highly species-specific. Anopheles stephensi infected with an African Plasmodium falciparum strain showed elevated flight activity throughout infection, an increased tendency to blood-feed upon host contact, and prolonged feeding times. In contrast, infection with an Asian P. falciparum strain or P. vivax had little impact on An. stephensi behavior. We detected no behavioral changes associated with P. falciparum infection in Anopheles gambiae s.s. or Anopheles coluzzii. Interestingly, dengue virus infection in Aedes aegypti increased landing, probing, and engorgement rates. Together, these results demonstrate that infection-induced behavioral change is not a general phenomenon among mosquito-borne pathogens, yet differs markedly per mosquito and pathogen species. A transmission model parameterized with our data showed that even modest behavioral shifts can substantially increase transmission, underscoring the potential epidemiological importance of subtle phenotypic shifts.

animal behavior and cognition↗

bioRxiv2025

BuzzWatch: uncovering multi-scale temporal patterns in mosquito behavior through continuous long-term monitoring

Understanding the temporal dynamics of mosquito behavior is essential for developing effective interventions against pathogen transmission. However, limited knowledge exists about the environmental, physiological, and genetic factors influencing mosquito activity patterns. This knowledge gap is partly due to a lack of tools to accurately quantify the behavior of free-flying mosquitoes over extended periods. Here, we introduce BuzzWatch, an open-source, low-cost platform designed to continuously monitor mosquito flight behavior over several weeks with high temporal resolution. BuzzWatch records videos of mosquitoes freely flying in a transparent cage and automates the extraction, analysis, and visualization of behavioral data, including flight trajectories and population-level flight and sugar-feeding statistics. Using BuzzWatch, we quantified the daily rhythms of 10 Aedes aegypti populations from various geographic origins. Globally invasive Ae. aegypti showed increased sugar feeding and flight activity during midday compared to native African populations. Our platform further revealed subtle, long-lasting effects of blood feeding on activity patterns and a complex response to extended daylight periods. By integrating a host-seeking module in BuzzWatch to deliver CO2 and heat pulses, we observed a twofold increase in Ae. aegyptis response to host-associated cues during the daytime compared to nighttime. Combined, these results demonstrate BuzzWatchs potential to investigate responses to host cues over seconds, natural variability in daily rhythms over hours, and phenotypic plasticity over days. BuzzWatch offers a novel perspective on mosquito behavior over multiple timescales, paving the way for advanced ecological and epidemiological studies that can inform targeted and effective vector control strategies. Short SummaryThis study introduces a new experimental platform to monitor multiple features of mosquito behavior (flight activity, sugar feeding, short-range host-seeking) with high temporal resolution over several weeks. HighlightsO_LIContinuous month-long tracking of mosquito flight activity in a laboratory setting. C_LIO_LIMultiscale analysis of flight behavior, from seconds to weeks. C_LIO_LIMapping of natural variation in daily rhythm of Aedes aegypti populations. C_LIO_LIQuantifying the long-lasting effect of physiological (blood-meal digestion) and environmental (photoperiod increase) perturbations. C_LIO_LIAutomatically monitoring response to short-range host-seeking cues at specific times of the day. C_LI

animal behavior and cognition↗

bioRxiv2022

Fundamental limits to progression of cellular life in frigid environments

Life on Earth, including for microbes and cold-blooded animals, often occurs in frigid environments. At frigid temperatures, nearly all intracellular processes slow down which is colloquially said to decelerate lifes pace and, potentially, aging. But even for one cell, an outstanding conceptual challenge is rigorously explaining how the slowed-down intracellular processes collectively sustain a cells life and set its pace. Here, by monitoring individual yeast cells for months at near-freezing temperatures, we show how global gene-expression dynamics and Reactive Oxygen Species (ROS) act together as the primary factors that dictate and constrain the pace at which a budding yeasts life can progresses in frigid environments. We discovered that yeast cells help each other in surviving and dividing at frigid temperatures. By investigating the underlying mechanism, involving glutathione secretion, we discovered that ROS is the primary determinant of yeasts ability to survive and divide at near-freezing temperatures. Observing days-to-months-long cell-cycle progression in individual cells revealed that ROS inhibits S-G2-M (replicative) phase while elongating G1 (growth) phase up to a temperature-dependent threshold duration, beyond which yeast cannot divide and bursts as an unsustainably large cell. We discovered that an interplay between global gene-expression speed and ROS sets the threshold G1-duration by measuring rates of genome-wide transcription and protein synthesis at frigid temperatures and then incorporating them into a mathematical model. The same interplay yields unbeatable "speed limits" for cell cycling - shortest and longest allowed doubling times - at each temperature. These results establish quantitative principles for engineering cold-tolerant microbes and reveal how frigid temperatures can fundamentally constrain microbial life and cell cycle at the systems-level.

systems biology↗

bioRxiv2019

Dormancy as a spectrum measuring spore’s proximity to death and to replicative life

Dormancy is colloquially considered as extending lifespan by being still. Starved yeasts form dormant spores that wake-up (germinate) when nutrients reappear but cannot germinate (die) after some time. What sets their lifespans and how they age are open questions because what processes occur - and by how much - within each dormant spore remains unclear. With single-cell-level measurements, we discovered how dormant yeast spores age and die: spores have a quantifiable gene-expressing ability during dormancy that decreases over days to months until it vanishes, causing death. Specifically, each spore has a different probability of germinating that decreases because its ability to - without nutrients - express genes decreases, as revealed by a synthetic circuit that forces GFP expression during dormancy. Decreasing amounts of molecules required for gene expression - including RNA polymerases - decreases gene-expressing ability which then decreases chances of germinating. Spores gradually lose these molecules because they are produced too slowly compared to their degradations, causing gene-expressing ability to eventually vanish and, thus, death. Our work provides a systems-level view of dormancy-to-death transition. Short summaryThis study identifies systems-level quantities that decay during dormancy in Saccharomyces cerevisiae spores and thereby reveals the meaning of ageing for dormant yeast spores and shows that they die when their gene-expressing ability is irreversibly lost. HighlightsO_LIFor a given glucose concentration, a dormant yeast spore has a well-defined probability of germinating ("germination ability"). C_LIO_LIA spores germination ability positively correlates with its RNAP I-III levels and the gene-expression (GFP) level it can realize when the expression is forced without nutrients. C_LIO_LIAgeing during dormancy means gradual decreases in germination ability, RNAP levels, and GFP-level realizable when expression is forced. C_LIO_LISpores die after sufficiently losing gene-expressing ability and drugs that inhibit gene expression during dormancy shorten spores lifespans (e.g., from months to a day). C_LI

systems biology↗