Current Biology最新文献

The retina is composed of discrete functional cell types that are also characterized by distinct morphology and gene expression. It remains, however, unclear whether similar discrete functional cell types exist in the visual regions downstream of the retina. Here, we used two-photon calcium imaging to investigate the response-space structure in the retina and in the superficial layers of the mouse superior colliculus (SC), a major retinorecipient area. We found that although retinal ganglion cells showed a clear dependence between responses to luminance and motion, responses to the two stimuli exhibited weaker couplings in collicular neurons. Because of this decoupling, functional clustering based on responses to both luminance and motion had significantly reduced separability compared with clustering based on responses to either. Our work suggests that the SC is not simply a relay station for retinal inputs but rather generates novel feature selectivity that diversifies cellular responses, perhaps through nonlinear neural processes involving the decoupling and recoupling of retinal ganglion cells' feature selectivity.

Imagine the tools a cow would make. This idea, humorously illustrated in Gary Larson's Far Side cartoon, captures a widespread assumption: cows are neither problem-solvers nor tool users. In science, as in culture, livestock species are often cognitively underestimated, reinforced by their utilitarian role and persistent mind-denial biases associated with meat consumption¹. Despite over 10,000 years of domestication, research on cattle cognition remains scarce and confined to applied contexts such as productivity and welfare². Tool use, while rarely observed, offers a stringent test of cognitive flexibility. Defined as the manipulation of an external object to achieve a goal via a mechanical interface³, tooling ranges from species-typical routines to innovative, problem-specific acts^4,5. We report here our experimental demonstration of flexible egocentric tooling in a pet cow (Bos taurus), Veronika, who uses a deck brush to self-scratch. Across randomized trials, she preferred the bristled end but switched to the stick end when targeting softer lower-body areas. This adaptive deployment of tool features reveals multi-purpose tool use not previously reported in non-primate mammals. Our findings broaden the taxonomic scope of flexible tool use and invite a reassessment of livestock cognition. VIDEO ABSTRACT.

Eukaryotes usually inherit genetic material from their parents, but occasional cross-species transfers can occur. A new study finds that these exchanges are surprisingly common in fungi, revealing an overlooked route for mobile elements to persist and impact host genomes.

The diversification of Hymenoptera is a transformative evolutionary story in insect evolution, fundamentally tied to major global events like the Mid-Mesozoic Parasitoid Revolution (MMPR) and the Angiosperm Terrestrial Revolution (ATR). The recent paper by Jouault et al.¹ provided a first large-scale quantification of Hymenoptera diversification using fossil occurrence data through two complementary Bayesian methods: PyRate, which models origination and extinction dynamics, and the Bayesian Brownian Bridge (BBB), which estimates clade origination and extinction ages^2,3,4,5. In a critique, Boudinot et al.⁶ raise concerns that our analyses overfit a sparse fossil record, misinterpret extinction signals, and overlook the putative absence of a Permian Hymenoptera ghost lineage. However, these concerns were not accompanied by statistical tests. Moreover, the original methodological papers include extensive simulations and empirical evaluations explicitly designed to assess the robustness and behavior of these models under varying fossil recovery scenarios; we direct readers to those studies for full details^2,3,4,5,7. Here, we clarify our methodology and counter these claims. Far from undermining our work, the critique merely reiterates and highlights the interpretive caution that underpins our study.

Interview with Patrícia Izar, who studies the behavioral ecology, plasticity, and cognition of Platyrrhine primates at the University of São Paulo.

Chytrid fungi provide a model for studying foam-like cellularization, where nuclei that are dispersed throughout the cytoplasm are synchronously compartmentalized into daughter cells. This organization poses geometric challenges not faced by cells undergoing conventional cytokinesis or Drosophila monolayer cellularization, where nuclei are organized in linear or planar arrangements with ready access to the plasma membrane. We use the chytrid Spizellomyces punctatus to show that chytrid cellularization begins with migration of nuclei and their attached centrosomes to the plasma membrane, where centrosome-associated vesicles mark sites of membrane invagination. These vesicles then extend inward, resulting in tubular furrows that branch and merge to create a honeycomb of polyhedral membrane compartments-a cellularization foam-each with a nucleus and cilium. Using inhibitors and laser ablation, we show that tensile forces produced by actomyosin networks drive aphrogenesis (foam generation), while microtubules are important for foam patterning and ciliogenesis but are not essential for cellularization. Finally, we suggest that chytrids may have incorporated ancestral mechanisms associated with ciliogenesis to coordinate the association of internal nuclei with membrane furrows to solve the unique geometric challenges associated with aphrogenic cellularization.

Despite decades of research, little capability exists to reliably predict the impact of ocean noise on marine mammals.¹ Noise impact predictions require knowing the frequencies marine mammals can hear and their sensitivity to those sounds (e.g., the hearing threshold, or the susceptibility to noise-induced hearing loss). For odontocetes and pinnipeds, these are well documented using behavioral methods, where the animal is trained to respond to an audible signal,² or auditory evoked potential (AEP) methods, where the neural response of the brain is measured.² Both the hearing range and sensitivity for all species of baleen whales are currently unknown. We used a behavioral observation audiometry (BOA) hearing test method in free-ranging humpback whales (Megaptera novaeangliae). BOA is an established hearing test method used in human children incapable of understanding and carrying out the verbal instructions necessary to perform a hearing test.³ A minimum response level (MRL) is calculated from the lowest sound levels to which the subject shows a response.^3,4,5 It offers a useful estimate of hearing sensitivity when other options are unavailable. Here, this method was used to generate a predicted hearing curve for humpback whales, which was compared with an anatomically derived curve based on studies of the cochlear and middle ear.^6,7,8 The predictive hearing curve presented here, along with new evidence of higher frequency hearing, will assist regulators and stakeholders in assessing the potential impact of anthropogenic sound on large whales.

Chilling stress is an important abiotic stress that affects plant growth and development. When it specifically occurs during the reproductive development stage of higher plants, it can significantly affect crop yield. Previous research on chilling stress has mostly focused on the seedling stage. Our findings show that brief chilling inhibits ovule initiation and reduces seed number per fruit. This decrease is related to BRASSINAZOLE RESISTANT 1 (BZR1), whose translation efficiency is affected by the RNA-binding protein COLD SHOCK PROTEIN 2 (CSP2). CSP2 binds to BZR1 mRNA and leads to the decreased abundance of BZR1 mRNA on the polysomes. Further research suggests that CSP2 may negatively regulate the translation efficiency of BZR1 by altering the N⁶-methyladenosine modification of BZR1 mRNA. Our results uncover a novel regulatory mechanism underlying the effect of chilling stress on plant reproduction and provide clues to help maintain crop yields of multi-ovulate ovaries.

Organ morphogenesis requires tightly coordinated changes in cell shape and position, sometimes aided by transient cellular structures. In the C. elegans reproductive system, formation of the spermatheca-uterine valve involves a transient "core cell," but its function has remained unknown. Using long-term live imaging, cell-specific genetic perturbations, and biophysical assays, we show that the core cell mechanically guides valve morphogenesis through two mechanisms: it directs a sliding cell-cell junction that facilitates expansion of the valve's apical domain, and it promotes assembly of a contractile actomyosin network within the valve cell, essential for valve contraction and animal fertility. Ablation or softening of the transient core cell disrupted valve contractility and revealed a mechanical feedback loop in which resistance from the core cell reinforces actomyosin assembly in the valve. Our findings highlight how transient scaffold cells can coordinate morphogenesis in neighboring cells, ensuring precise and robust organ formation.