Human parvovirus B19 (B19V) is an ubiquitously spread, exclusively human pathogen, mainly posing risks to children, as well as pregnant and immunocompromised individuals. Despite evidence of B19V infection of human populations as far back as 7,000 years, the evolutionary history of B19V remains poorly understood. In this study, we present B19V genomic data from the remains of 53 globally distributed individuals spanning more than 8,000 years, including 7 children. Our findings suggest that the most recent common ancestor of all present B19V lineages existed around 12,000 years ago, at the end of the last Ice Age. Additionally, we identified an extinct Eurasian clade that participated in the recombination event that led to the emergence of B19V genotype 2 (GT-2). We date this event to ∼3,200-1,800 BP, potentially in the greater Mediterranean area. Our study shows aspects of how ancient parvovirus variants arose, disseminated, and impacted human health through time.
The endoplasmic reticulum (ER) interacts with virtually all other cellular organelles, and major players mediating these interactions are the ER-bound VAMP-associated protein (VAP) proteins VAPA and VAPB. Here, we show that VAP proteins interact with the actin polymerization factor INF2 in a phosphorylation-dependent manner. Similar to many other VAP-interacting proteins (the "VAPome"), an FFAT motif in INF2's C terminus interacts with the major sperm protein (MSP) domain of VAPs. Phosphorylation of a serine within the FFAT (S1100 in mouse; S1077 in human INF2) is necessary for high-affinity interaction both in cells and with purified proteins. The position of this phosphoserine, at position -1 of the FFAT consensus, is novel to the VAPome. Biochemical assays show that the phospho-FFAT binds both VAPA and VAPB, but not the related VAP family protein MOSPD2. Increased cytoplasmic calcium stimulates both INF2 phosphorylation and the INF2/VAP interaction. Amyotrophic lateral sclerosis (ALS)-associated mutations in the MSP disrupt the INF2/VAP interaction. Both major INF2 isoforms interact with VAPs: the INF2-CAAX isoform, which is constitutively ER-bound, and the INF2-nonCAAX isoform, which is predominantly cytosolic. For INF2-nonCAAX, VAP proteins cause ER recruitment in a phosphorylation-dependent manner. Disruption of INF2/VAP binding does not affect INF2-mediated actin polymerization but has a clear effect on ER morphology, causing the tubule/sheet balance to shift toward sheets. Cross-species evaluation suggests that only INF2 from placental mammals possesses an FFAT. These results suggest that interaction between VAP proteins and the actin polymerization factor INF2 plays a role in mediating ER morphology.
Large predators can run afoul of people when they kill or frighten game species and livestock. A new study reveals that pumas enhance human safety by scaring deer away from roads and reducing vehicle collisions.
Ninon Lecoquierre and colleagues introduce the dicyemids, microscopic animals at the edge of simplicity.
Movie theaters, televisions, and streaming services sometimes crop movies, cutting off the sides or the top and bottom of the image to accommodate differently shaped screens. The Odyssey is the most recent example to provoke controversy, with some critics and aficionados objecting to presentations that omit portions of its full IMAX frame. Typical viewers may shrug and choose the most convenient theater. Are they missing anything important? Recent research suggests that they may be.
A continent-wide analysis of banding data shows that North American birds aren't declining for a single shared reason. Each bird species responds to its own specific environmental triggers, and those triggers can be predicted from a species' traits.
Morphological transitions underlie fungal pathogenicity. Transitions to pathogenic growth forms are well studied, but morphological reversions are not, despite their importance for fungal commensalism. A new study addresses this, revealing mechanisms by which a bacterial polyketide triggers hypha-to-yeast morphogenesis in Candida albicans.
In addition to space, the hippocampus can represent relevant goals such as reward sites. New findings demonstrate that locally acting vasoactive intestinal peptide (VIP)-expressing interneurons selectively and powerfully regulate the updating of reward coding while leaving spatial maps intact.
The classic Notch-mediated lateral-inhibition model for cell fate specification has been overturned: Drosophila neuroblasts are selected before germ-band extension, which involves asymmetries in position, proneural gene expression, geometry and junctional mechanics. Notch plays a later role in reinforcing neuroblast fate.
A new study identifies the chemical features of cat urine that provide distinctive, individual signatures. The branched-chain fatty acids that confer a chemical nametag for cat urine represent a novel system previously undescribed in mammals.
How does a neuron develop only one axon? A recent study shows that axon specification is preceded by an oscillatory programme in which actin waves periodically discharge from the cell body into individual neurites, transiently overcoming contractility. This local-activation, global-inhibition mechanism ensures only one neurite at a time can grow.
Group work is common in undergraduate STEM classrooms and is associated with several benefits for student learning. However, its effectiveness may be limited by the Ringelmann effect, whereby individual effort decreases as group size increases. In contrast to humans, recent work shows that weaver ants are not subject to the Ringelmann effect when working collaboratively. In this essay, we consider what big lessons can be drawn from small insects that can in turn inform teaching strategies to enhance group work for students. We propose three insect-inspired recommendations: design group-worthy tasks, embrace the division of labor and develop shared rules of engagement. Taking inspiration from the natural world, instructors can look to the behaviors of social insects to maximize the positive effects of group work in undergraduate classrooms.
Road traffic is a fundamental component of modern human society. Recently, tire wear particles, generated by road traffic through friction between tires and road surfaces, have been increasingly recognized as toxic to a wide range of organisms. While previous studies have examined impacts on aquatic ecosystems or edible plants (i.e., crops), the effects of tire wear particles on urban green spaces, such as parks and roadside vegetation belts located close to roads, have remained largely unexplored. Here, we conducted a tire wear particle exposure experiment using Bromus catharticus, a common roadside weed species in Japan. Our results demonstrated tire wear particles significantly inhibited both shoot and root growth. In addition, the particles significantly elevated oxidative stress, assessed by malondialdehyde (MDA) content, in roots. These findings show the potential for widespread impacts of tire wear particle contamination in urban green ecosystems.
Nectar is a hub for plant-pollinator interactions, yet gene-level causal links between plant genetic variation, pollinator foraging, and nectar microbial assembly remain poorly resolved. Using near-isogenic lines, innovative field time-lapse monitoring of pollinator visits, and long-read amplicon sequencing of nectar microbiota, we show that a natural single-nucleotide variant at a cell-wall invertase gene (HaCWINV2) controls sunflower nectar chemistry and influences both pollinators and microbes. Plants homozygous for a loss-of-function HaCWINV2 allele produce sucrose-rich nectar, resulting in fewer bee visits under field conditions. In pollinator-excluded flowers, invertase-deficient plants harbored greater fungal diversity and compositionally distinct communities, indicating that nectar sugar profiles act as ecological filters shaping the nectar microbiome. This loss-of-function allele is rare in wild sunflowers, but fixed in 35% of cultivated lines, indicating positive selection during domestication. Our findings establish a causal link between a single gene and nectar chemistry, with cascading ecological effects in a plant-pollinator system, thus illustrating how subtle genetic changes scale up to alter nectar traits, microbial assembly, and pollinator foraging behavior.
Root hairs (RHs) are critical for nutrient acquisition, yet the mechanisms by which their elongation is calibrated to environmental cues remain poorly understood. While the lateral root cap (LRC) physically encases the root tip, its potential regulatory role in determining the fate of the neighboring epidermis has been largely overlooked. In this study, we demonstrate that the persistence of LRC is required for a transient signaling hub that remotely controls RH elongation in Arabidopsis. The LRC-localized NAC transcription factor SOMBRERO acts as the integrative hub of an auxin-driven communication pathway between the LRC and epidermis. Specifically, ANAC033/SOMBRERO (SMB) coordinates auxin transport and biosynthesis by regulating the expression of AUX1 and the indole-3-butyric acid (IBA)-to-IAA conversion gene ECH2, which cooperatively create auxin maxima in the epidermis to drive RH elongation. Furthermore, we showed that SOMBRERO is required for maintaining basal expression levels of genes associated with RH development and acquisition of nitrogen and phosphorus, thereby regulating the RH responses to external nutrient conditions. Our findings uncover a non-cell-autonomous mechanism within the LRC through which SMB activates a precise transcriptional circuit that is coordinated with the LRC developmental program to optimize RH foraging strategies under fluctuating environments.
The extinct “American cheetah” (Miracinonyx trumani) has long been considered a North American ecological analog of the African cheetah1,2 (Acinonyx jubatus) based on convergent cursorial morphology, yet this paradigm rests on limited data3 and untested assumptions about its evolutionary relationships and ecology.2,4 Here, we generate nuclear paleogenomes from M. trumani specimens from Wyoming (∼23 kya; thousand years ago) and Yukon (∼31 kya), definitively placing this enigmatic felid within the evolutionary tree of cats. Phylogenomic analyses confirm M. trumani as sister to pumas (Puma concolor), not cheetahs, with a divergence of ∼2.6 million years ago (mya) during rapid Pliocene-Pleistocene climate oscillations. The Yukon specimens extend the species’ known range2 by over 20° latitude into the Arctic, and stable isotope analyses reveal striking ecological differentiation, with the Yukon population occupying an elevated trophic position consistent with exploitation of anadromous fish, while the Wyoming population functioned as a generalist terrestrial predator. This evidence suggests that M. trumani exhibited remarkable ecological versatility, while loss-of-function mutations in circadian genes may reflect relaxed constraints on circadian regulation. Together, these findings underscore how morphological convergence can obscure the true diversity and complexity of extinct megafaunal ecosystems.
The nucleus accumbens (NAc) orchestrates a range of critical physiological functions, including reward and motivation, yet single-neuron-level connectivity of its inputs and outputs remains less comprehensively characterized. Here, we examined the organizing principle of input and projection of medium spiny neurons (MSNs) across NAc in adult male mice at single-cell resolution. Our results revealed topographic distribution principles of these neurons and their terminals in the substantia innominata (SI) subdivision. Rabies virus tracing uncovered different monosynaptic inputs to Tac2+ (D1 subtype) versus Calcr+ (D2 subtype) MSNs across NAc subregions. Furthermore, cortical neurons projecting to NAc core or shell showed distinct cortical origins and collateralization. Hippocampal neurons projecting to the NAc preferentially innervate the core and medial shell with longitudinal topography and the strongest co-projection to the hypothalamus. Together, these data delineated the neuronal connectivity patterns of different neuronal subtypes in NAc, providing an anatomical basis for further understanding the neural circuit mechanisms underlying the functional role of NAc.
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in MECP2. Disordered breathing is a hallmark feature of RTT that negatively impacts quality of life and can be life-threatening. Despite this, the mechanisms underlying disordered breathing in RTT are poorly understood. Although RTT is primarily considered a central nervous system disorder, we found that increased drive from peripheral respiratory chemoreceptors may contribute to unstable breathing in MeCP2-deficient mice. Consistent with this, breathing pure oxygen to limit the output of peripheral chemoreceptors stabilized breathing in MeCP2-deficient mice. Also, knockdown of MeCP2 within the carotid body recapitulates RTT-like unstable breathing. We also found that MeCP2 deficiency alters the carotid body transcriptome, including the disruption of genes involved in dopaminergic signaling, and treatment with a dopamine receptor agonist stabilized breathing in MeCP2-deficient mice. These results identify the peripheral chemoreceptors as high-priority therapeutic targets for disordered breathing in RTT.
Snake embryos are often tightly coiled, but the biological basis for this developmental trait remains a puzzle. To understand how and why they coil, we first investigated directions of coiling within and across 39 snake and other limbless squamate species. In early developmental stages, coiling orientation appears to be nearly fixed right-handed across multiple species. We present evidence that accelerated somitogenesis outpaces gastrointestinal extension at these stages, causing the axial column and somitic series to coil around the delayed visceral tissues. To allow this, the body axis and the gut are physically separate, where the latter forms a pillar-like structure from the stomach to the cloaca. The initial dextral directional bias in these early embryos is likely passively determined by the left-sided yolk mass. Coiling becomes looser and more inconsistent later in development when the embryos acquire mobility through maturation of axial musculoskeletal tissues and with a sufficiently extended gut. These consilient lines of observations reveal, in embryonic coiling, a series of responses of the growing tissues to spatial limitations during snake embryogenesis. As these parameters conflict at some developmental stages (e.g., the offset growth curves between the gut and the body axis), snakes apparently solve some of the many challenges to patterning their startlingly elongate bodies by coiling, which takes advantage of what could otherwise be discordant features of embryonic growth.
Animals exhibit sex-specific behaviors that are governed by sexually dimorphic circuits. One such behavior in male Drosophila melanogaster, courtship, is regulated by various sensory modalities, including olfaction. Here, we reveal how sexually dimorphic olfactory pathways in male flies converge onto lateral horn output neurons, third-order neurons in the olfactory circuit, to regulate courtship. To achieve this, we developed ds-Tango, a modified version of the monosynaptic tracing and manipulation tool trans-Tango. In ds-Tango, two distinct configurations of trans-Tango are positioned in series, thus providing selective genetic access not only to the monosynaptic partners of starter neurons but also to their disynaptic connections. Using ds-Tango, we identified a node of convergence for three sexually dimorphic olfactory pathways. Males in which this node is silenced aberrantly court other males, unless a female is present. Thus, our results identify lateral horn output neurons important for proper courtship behavior and establish ds-Tango as a tool for disynaptic circuit tracing.
