Biology subjects

Bellono, N. W.

Publications and source records attributed to Bellono, N. W..

7 recordsLinked to original sources

bioRxiv2026

Evolution of a core ribosomal innovation in octopus

Much of biology focuses on how genetic changes mediate new functions, but less attention is given to adaptations in other steps of the central dogma. Octopuses exhibit complex nervous systems and sophisticated behaviors that rival vertebrates, but via an entirely divergent evolutionary history. Here, we serendipitously discovered that octopus ribosomes contain a structural break in the core ribosomal RNA that is unique among all animals. This break site enhances translation fidelity to reduce miscoding and subsequent protein aggregation, even when engineered into evolutionarily distant bacterial ribosomes. Furthermore, high fidelity translation by octopus ribosomes supports proteomic stability during extensive RNA editing observed in cephalopods, suggesting synergy between distinct non-canonical modes of gene regulation. This adaptation emerged in recently derived octopuses with expanded nervous systems, thereby revealing a mechanism that could broadly support the evolution of novel organismal traits.

biochemistry↗

bioRxiv2026

An ancient receptor family illuminates the evolution of animal sensation

Animals use nervous systems to sense and respond to their environment. Yet single-celled organisms can also detect cues to execute diverse behaviors, suggesting that core components for animal sensation predate multicellularity and nervous systems. Here, we report that choanoflagellates, the closest living animal relatives, use an ancient sensory receptor family to detect bacterial prey. These receptors are related to transient receptor potential ion channels but are distinguished by WD40 domains, defining TRPW. TRPW1 detects specific bacterial lipids to modulate flagellar beating, providing a mechanism for attraction towards prey. TRPW emerged in early eukaryotes and reveals ancestral architectural and ligand-binding features that predate animal somatosensory receptors. In multicellular choanoflagellates, TRPW1 elicits collective responses, linking bacterial ecology to the evolution of receptors, sensory organelles, and multicellular life.

evolutionary biology↗

bioRxiv2026

Hierarchical processing and polarization encoding in the cephalopod visual system

Coleoid cephalopods (octopus, cuttlefish and squid, hereafter cephalopods) have evolved a range of complex visually-guided behaviours, from dexterous hunting to skin-pattern based camouflage and communication1. They have also evolved sensitivity to the polarization of light2, an adaptation thought to help detect camouflaged or semitransparent predators and prey in low visibility underwater environments3-10. How visual information is processed by the cephalopod brain to support their behaviours remains unclear. Here, studying the bigfin reef squid Sepioteuthis lessoniana, we performed calcium imaging and electrophysiological recordings from populations of neurons in the large visual center of the cephalopod brain, the optic lobe (OL). We revealed that the retina-recipient superficial OL contains a diversity of functionally distinct cell types, spatially organized into sub-layers, processing spatio-temporal features of light intensity and possessing polarization angle specificity. More complex features, e.g. direction selectivity, are seen in deeper regions of the OL cortex, which also exhibits spontaneous waves of neural activity in the absence of visual input. Neurons in the downstream OL medulla exhibit visual receptive field sizes and spontaneous activity levels which increase with brain depth, consistent with the hierarchical processing of visual information through the medullas tree-like anatomical organization. Medulla neurons exhibit sensitivity to local decreases in the degree of linear polarization (DoLP), which they integrate additively with light intensity information. Underwater imaging in the squids habitat off the coast of Okinawa, Japan, demonstrate that polarization sensitivity confers a robust short-range boost in object-background contrast over a range of objects and environmental conditions. These findings reveal convergent principles of hierarchical visual processing shared between cephalopods and vertebrates, and highlight how cephalopods utilise their distinct adaptation of polarization sensitivity to solve universal visual challenges underwater.

neuroscience↗

bioRxiv2025

A sensory system for mating in octopus

Sensory systems for mate recognition maintain species boundaries and influence diversification. Therefore, uncovering how molecules and receptors evolve to mediate this critical function is essential to understanding biodiversity. Male octopuses use a specialized arm called the hectocotylus to identify females and navigate their internal organs to reach the oviduct and deliver sperm. Here, we discovered that the hectocotylus is a dual sensory and mating organ that uses contactdependent chemosensation of progesterone, a conserved ovarian hormone. We identify chemotactile receptors for progesterone and resolve the structural basis for their evolution from ancestral neurotransmitter receptors and subsequent expansion and tuning across cephalopods. These findings reveal principles by which sensory innovations shape reproductive behavior and suggest mechanisms for how sensory evolution contributes to the diversification of life.

cell biology↗

bioRxiv2023

The genetic basis of novel trait gain in walking fish

A major goal in biology is to understand how organisms evolve novel traits. Multiple studies have identified genes contributing to regressive evolution, the loss of structures that existed in a recent ancestor. However, fewer examples exist for genes underlying constructive evolution, the gain of novel structures and capabilities in lineages that previously lacked them. Sea robins are fish that have evolved enlarged pectoral fins, six mobile locomotory fin rays (legs) and six novel macroscopic lobes in the central nervous system (CNS) that innervate the corresponding legs. Here, we establish successful husbandry and use a combination of transcriptomics, CRISPR-Cas9 editing, and behavioral assays to identify key transcription factors that are required for leg formation and function in sea robins. We also generate hybrids between two sea robin species with distinct leg morphologies and use allele-specific expression analysis and gene editing to explore the genetic basis of species-specific trait diversity, including a novel sensory gain of function. Collectively, our study establishes sea robins as a new model for studying the genetic basis of novel organ formation, and demonstrates a crucial role for the conserved limb gene tbx3a in the evolution of chemosensory legs in walking fish.

evolutionary biology↗

bioRxiv2023

Molecular tuning of sea anemone stinging

Jellyfish and sea anemones fire single-use, venom-covered barbs to immobilize prey or predators. We previously showed that the anemone Nematostella vectensis uses a specialized voltage-gated calcium (CaV) channel to trigger stinging in response to synergistic prey-derived chemicals and touch (Weir et al., 2020). Here we use experiments and theory to find that stinging behavior is suited to distinct ecological niches. We find that the burrowing anemone Nematostella uses uniquely strong CaV inactivation for precise control of predatory stinging. In contrast, the related anemone Exaiptasia diaphana inhabits exposed environments to support photosynthetic endosymbionts. Consistent with its niche, Exaiptasia indiscriminately stings for defense and expresses a CaV splice variant that confers weak inactivation. Chimeric analyses reveal that CaV{beta} subunit adaptations regulate inactivation, suggesting an evolutionary tuning mechanism for stinging behavior. These findings demonstrate how functional specialization of ion channel structure contributes to distinct organismal behavior.

physiology↗

bioRxiv2020

A molecular filter for the cnidarian stinging response

All animals detect and integrate diverse environmental signals to mediate behavior. Cnidarians, including jellyfish and sea anemones, both detect and capture prey using stinging cells called nematocytes which fire a venom-covered barb via an unknown triggering mechanism. Here, we show that nematocytes from Nematostella vectensis use a specialized voltage-gated calcium channel (nCav) to distinguish salient sensory cues and control the explosive discharge response. Adaptations in nCav confer unusually-sensitive, voltage-dependent inactivation to inhibit responses to non-prey signals, such as mechanical water turbulence. Prey-derived chemosensory signals are synaptically transmitted to acutely relieve nCav inactivation, enabling mechanosensitive-triggered predatory attack. These findings reveal a molecular basis for the cnidarian stinging response and highlight general principles by which single proteins integrate diverse signals to elicit discrete animal behaviors.

physiology↗