Offspring nursing extends mother's longevity in a long-term maternal cared spider.

Females typically outlive males in animals, especially in species that provide long-term maternal care. However, life history theory predicts that investments in reproduction, such as lactation and offspring nursing, often shorten caretakers' longevity. Aiming to interpret this paradox, we selected the lactating jumping spider Toxeus magnus to investigate the effects of reproductive activities on longevity for two sexes. We found that: (1) although "milk" provisioning reduces female's longevity, mothers who cared for offspring (provisioned "milk" and nursing) lived the longest compared to virgins and those did not provide care; (2) copulation increased female's longevity but had no effects on males; and (3) the two sexes have comparable developmental duration, but the female adult's longevity was 2.1 times that of male's. This study suggests that the time requirement for offspring dispersal might act as a key selective force favoring females' adulthood extension, which ultimately generates the longer-lived females in maternal cared species.

Sporadic feeding regulates robust food entrainable circadian clocks in blind cavefish.

The circadian clock represents a key timing system entrained by various periodic signals that ensure synchronization with the environment. Many investigations have pointed to the existence of two distinct circadian oscillators: one regulated by the light-dark cycle and the other set by feeding time. Blind cavefish have evolved under extreme conditions where they completely lack light exposure and experience food deprivation. Here, we have investigated feeding regulated clocks in two cavefish species, the Somalian cavefish Phreatichthys andruzzii and the Mexican cavefish Astyanax mexicanus, in comparison with the surface-dwelling zebrafish Danio rerio. Our results reveal that feeding represents an extremely strong synchronizer for circadian locomotor rhythmicity in subterranean cavefish. Indeed, we showed that consuming just one meal every 4 days is sufficient to entrain circadian rhythmicity in both cavefish species, but not in zebrafish. These profound adaptations to an extreme environment provide insight into the connections between feeding and circadian clocks.

Early evolution of the ecdysozoan body plan.

Extant ecdysozoans (moulting animals) are represented by a great variety of soft-bodied or articulated organisms that may or may not have appendages. However, controversies remain about the vermiform nature (i.e. elongated and tubular) of their ancestral body plan. We describe here Beretella spinosa gen. et sp. nov. a tiny (maximal length 3 mm) ecdysozoan from the lowermost Cambrian, Yanjiahe Formation, South China, characterized by an unusual sack-like appearance, single opening, and spiny ornament. Beretella spinosa gen. et sp. nov has no equivalent among animals, except Saccorhytus coronarius, also from the basal Cambrian. Phylogenetic analyses resolve both fossil species as a sister group (Saccorhytida) to all known Ecdysozoa, thus suggesting that ancestral ecdysozoans may have been non-vermiform animals. Saccorhytids are likely to represent an early off-shot along the stem-line Ecdysozoa. Although it became extinct during the Cambrian, this animal lineage provides precious insight into the early evolution of Ecdysozoa and the nature of the earliest representatives of the group.

A universal preference for animate agents in hominids.

When conversing, humans instantaneously predict meaning from fragmentary and ambiguous mspeech, long before utterance completion. They do this by integrating priors (initial assumptions about the world) with contextual evidence to rapidly decide on the most likely meaning. One powerful prior is attentional preference for agents, which biases sentence processing but universally so only if agents are animate. Here, we investigate the evolutionary origins of this preference, by allowing chimpanzees, gorillas, orangutans, human children, and adults to freely choose between agents and patients in still images, following video clips depicting their dyadic interaction. All participants preferred animate (and occasionally inanimate) agents, although the effect was attenuated if patients were also animate. The findings suggest that a preference for animate agents evolved before language and is not reducible to simple perceptual biases. To conclude, both humans and great apes prefer animate agents in decision tasks, echoing a universal prior in human language processing.

The trunk replaces the longer mandible as the main feeding organ in elephant evolution.

The long-trunked elephantids underwent a significant evolutionary stage characterized by an exceptionally elongated mandible. The initial elongation and subsequent regression of the long mandible, along with its co-evolution with the trunk, present an intriguing issue that remains incompletely understood. Through comparative functional and eco-morphological investigations, as well as feeding preference analysis, we reconstructed the feeding behavior of major groups of longirostrine elephantiforms. In the Platybelodon clade, the rapid evolutionary changes observed in the narial region, strongly correlated with mandible and tusk characteristics, suggest a crucial evolutionary transition where feeding function shifted from the mandible to the trunk, allowing proboscideans to expand their niches to more open regions. This functional shift further resulted in elephantids relying solely on their trunks for feeding. Our research provides insights into how unique environmental pressures shape the extreme evolution of organs, particularly in large mammals that developed various peculiar adaptations during the late Cenozoic global cooling trends.

The elephant's trunk is one of the most efficient food-gathering organs in the animal kingdom. From large branches to thin blades of grass, it can coil around and bring many types of vegetation to the animals' strong, short mandibles. This versatility allows elephants to thrive in a range of environments, including grasslands. Trunks are not the only spectacular feature to emerge in Proboscideans, the family of which elephants are the only surviving group. During the early and middle Miocene (between 23 to 11.6 million years ago), many of these species had dramatically elongated lower jaws; how and why this trait emerged then disappeared is poorly understood. The role that lengthened mandibles and trunks played during feeding also remains unclear. To address these questions, Li et al. focused on Platybelodon, Choerolophodon and Gomphotherium, which belong to three Proboscidean families that roamed Northern China between 17 and 15 million years ago. Each had elongated lower jaws, but with strikingly distinct lengths and morphologies. Chemical analyses on enamel samples helped determine which habitat the families occupied, while mathematical modelling revealed how their mandibles tackled different types of plants. Trunk shape was assessed via analyses of the nasal region. The results suggest that Choerolophodon had mandibles better suited for processing branches and a short, 'primitive' trunk. Gomphotherium sported a versatile jaw that could handle both grass and trees, as well as a rather 'elephant-like' trunk. The jaw of Platybelodon seemed well-adapted to cut grass, and remarkable bone structures point towards a long, strong and flexible trunk. While modern elephants fully depend on their trunks to eat, morphological constraints suggest that, in these species, the appendage only served to assist feeding (e.g., by pressing down on branches). All families shared an environment that included grasslands and forests, but analyses suggest that, for a period, Choerolophodon favored relatively closed habitats while Platybelodon spread into grasslands and Gomphotherium navigated both landscapes. This suggests that the evolution of long, strong and flexible trunks is tightly associated with grazing. About 14 million years ago, a global cooling event led to grasslands expanding worldwide. The fossil record shows the mandibles of Proboscideans starting to shorten after this period, including in the descendants of Gomphotherium that would give rise to modern elephants. The work by Li et al. sheds light onto these evolutionary processes, and the environmental pressures which helped shape the trunk.

Malate dehydrogenase in plants: evolution, structure, and a myriad of functions.

Malate dehydrogenase (MDH) catalyzes the interconversion of oxaloacetate and malate coupled to the oxidation/reduction of coenzymes NAD(P)H/NAD(P)+. While most animals have two isoforms of MDH located in the cytosol and mitochondria, all major groups of land plants have at least six MDHs localized to the cytosol, mitochondria, plastids, and peroxisomes. This family of enzymes participates in important reactions in plant cells including photosynthesis, photorespiration, lipid metabolism, and NH4+ metabolism. MDH also helps to regulate the energy balance in the cell and may help the plant cope with various environmental stresses. Despite their functional diversity, all of the plant MDH enzymes share a similar structural fold and act as dimers. In this review, we will introduce readers to our current understanding of the plant MDHs, including their evolution, structure, and function. The focus will be on the MDH enzymes of the model plant Arabidopsis thaliana.

Sex-biased regulatory changes in the placenta of native highlanders contribute to adaptive fetal development.

Compared with lowlander migrants, native Tibetans have a higher reproductive success at high altitude though the underlying mechanism remains unclear. Here, we compared the transcriptome and histology of full-term placentas between native Tibetans and Han migrants. We found that the placental trophoblast shows the largest expression divergence between Tibetans and Han, and Tibetans show decreased immune response and endoplasmic reticulum stress. Remarkably, we detected a sex-biased expression divergence, where the male-infant placentas show a greater between-population difference than the female-infant placentas. The umbilical cord plays a key role in the sex-biased expression divergence, which is associated with the higher birth weight of the male newborns of Tibetans. We also identified adaptive histological changes in the male-infant placentas of Tibetans, including larger umbilical artery wall and umbilical artery intima and media, and fewer syncytial knots. These findings provide valuable insights into the sex-biased adaptation of human populations, with significant implications for medical and genetic studies of human reproduction.

Evolutionary druggability for low-dimensional fitness landscapes toward new metrics for antimicrobial applications.

The term 'druggability' describes the molecular properties of drugs or targets in pharmacological interventions and is commonly used in work involving drug development for clinical applications. There are no current analogues for this notion that quantify the drug-target interaction with respect to a given target variant's sensitivity across a breadth of drugs in a panel, or a given drug's range of effectiveness across alleles of a target protein. Using data from low-dimensional empirical fitness landscapes composed of 16 ß-lactamase alleles and 7 ß-lactam drugs, we introduce two metrics that capture (i) the average susceptibility of an allelic variant of a drug target to any available drug in a given panel ('variant vulnerability'), and (ii) the average applicability of a drug (or mixture) across allelic variants of a drug target ('drug applicability'). Finally, we (iii) disentangle the quality and magnitude of interactions between loci in the drug target and the seven drug environments in terms of their mutation by mutation by environment (G x G x E) interactions, offering mechanistic insight into the variant variability and drug applicability metrics. Summarizing, we propose that our framework can be applied to other datasets and pathogen-drug systems to understand which pathogen variants in a clinical setting are the most concerning (low variant vulnerability), and which drugs in a panel are most likely to be effective in an infection defined by standing genetic variation in the pathogen drug target (high drug applicability).

Copy number variation and population-specific immune genes in the model vertebrate zebrafish.

Copy number variation in large gene families is well characterized for plant resistance genes, but similar studies are rare in animals. The zebrafish (Danio rerio) has hundreds of NLR immune genes, making this species ideal for studying this phenomenon. By sequencing 93 zebrafish from multiple wild and laboratory populations, we identified a total of 1513 NLRs, many more than the previously known 400. Approximately half of those are present in all wild populations, but only 4% were found in 80% or more of the individual fish. Wild fish have up to two times as many NLRs per individual and up to four times as many NLRs per population than laboratory strains. In contrast to the massive variability of gene copies, nucleotide diversity in zebrafish NLR genes is very low: around half of the copies are monomorphic and the remaining ones have very few polymorphisms, likely a signature of purifying selection.

Humans and other animals have immune systems that protect them from bacteria, viruses and other potentially harmful microbes. Members of a family of genes known as the NLR family play various roles in helping to recognize and destroy these microbes. Different species have varying numbers of NLR genes, for example, humans have 22 NLRs, but fish can have hundreds. 400 have been found in the small tropical zebrafish, also known as zebra danios. Zebrafish are commonly used as model animals in research studies because they reproduce quickly and are easy to keep in fish tanks. Much of what we know about fish biology comes from studying strains of those laboratory zebrafish, including the 400 NLRs found in a specific laboratory strain. Many NLRs in zebrafish are extremely similar, suggesting that they have only evolved fairly recently through gene duplication. It remains unclear why laboratory zebrafish have so many almost identical NLRs, or if wild zebrafish also have lots of these genes. To find out more, Schäfer et al. sequenced the DNA of NLRs from almost 100 zebrafish from multiple wild and laboratory populations. The approach identified over 1,500 different NLR genes, most of which, were previously unknown. Computational modelling suggested that each wild population of zebrafish may harbour up to around 2,000 NLR genes, but laboratory strains had much fewer NLRs. The numbers of NLR genes in individual zebrafish varied greatly ­ only 4% of the genes were present in 80% or more of the fish. Many genes were only found in specific populations or single individuals. Together, these findings suggest that the NLR family has expanded in zebrafish as part of an ongoing evolutionary process that benefits the immune system of the fish. Similar trends have also been observed in the NLR genes of plants, indicating there may be an evolutionary strategy across all living things to continuously diversify large families of genes. Additionally, this work highlights the lack of diversity in the genes of laboratory animals compared with those of their wild relatives, which may impact how results from laboratory studies are used to inform conservation efforts or are interpreted in the context of human health.

Fitness landscape of substrate-adaptive mutations in evolved amino acid-polyamine-organocation transporters.

The emergence of new protein functions is crucial for the evolution of organisms. This process has been extensively researched for soluble enzymes, but it is largely unexplored for membrane transporters, even though the ability to acquire new nutrients from a changing environment requires evolvability of transport functions. Here, we demonstrate the importance of environmental pressure in obtaining a new activity or altering a promiscuous activity in members of the amino acid-polyamine-organocation (APC)-type yeast amino acid transporters family. We identify APC members that have broader substrate spectra than previously described. Using in vivo experimental evolution, we evolve two of these transporter genes, AGP1 and PUT4, toward new substrate specificities. Single mutations on these transporters are found to be sufficient for expanding the substrate range of the proteins, while retaining the capacity to transport all original substrates. Nonetheless, each adaptive mutation comes with a distinct effect on the fitness for each of the original substrates, illustrating a trade-off between the ancestral and evolved functions. Collectively, our findings reveal how substrate-adaptive mutations in membrane transporters contribute to fitness and provide insights into how organisms can use transporter evolution to explore new ecological niches.

The mechanism of Andrena camellia in digesting toxic sugars.

Camellia oleifera is an economically and medicinally valuable oilseed crop. Honeybee, the most abundant pollinator, rarely visits C. oleifera because of the toxic sugars in the nectar and pollen. These toxic sugars cannot be fully digested by honeybees and inhibit the process of synthesizing trehalose in honeybees. C. oleifera exhibits self-incompatibility, and its pollination heavily depends on Andrena camellia. However, the mechanism by which A. camellia digests toxic sugars in C. oleifera nectar and pollen remains unknown. Consequently, we identified and validated four single-copy genes (α-N-acetyl galactosamine-like, galactokinase, galactose-1-phosphate uridyltransferase, and UDP-galactose-4'-epimerase, abbreviated as NAGA-like, GALK, GALT, and GALE) essential for detoxifying toxic sugars in vitro. Then, we cloned the four genes into Escherichia coli, and expressed enzyme successfully degraded the toxic sugars. The phylogeny suggests that the genes were conserved and functionally diverged among the evolution. These results provide novel insights into pollinator detoxification during co-evolution.

Helpless infants are learning a foundation model.

Humans have a protracted postnatal helplessness period, typically attributed to human-specific maternal constraints causing an early birth when the brain is highly immature. By aligning neurodevelopmental events across species, however, it has been found that humans are not born with especially immature brains compared with animal species with a shorter helpless period. Consistent with this, the rapidly growing field of infant neuroimaging has found that brain connectivity and functional activation at birth share many similarities with the mature brain. Inspired by machine learning, where deep neural networks also benefit from a 'helpless period' of pre-training, we propose that human infants are learning a foundation model: a set of fundamental representations that underpin later cognition with high performance and rapid generalisation.

The evolution of olfactory sensitivity, preferences, and behavioral responses in Mexican cavefish is influenced by fish personality.

Animals are adapted to their natural habitats and lifestyles. Their brains perceive the external world via their sensory systems, compute information together with that of internal states and autonomous activity, and generate appropriate behavioral outputs. However, how do these processes evolve across evolution? Here, focusing on the sense of olfaction, we have studied the evolution in olfactory sensitivity, preferences, and behavioral responses to six different food-related amino acid odors in the two eco-morphs of the fish Astyanax mexicanus. To this end, we have developed a high-throughput behavioral setup and pipeline of quantitative and qualitative behavior analysis, and we have tested 489 six-week-old Astyanax larvae. The blind, dark-adapted morphs of the species showed markedly distinct basal swimming patterns and behavioral responses to odors, higher olfactory sensitivity, and a strong preference for alanine, as compared to their river-dwelling eyed conspecifics. In addition, we discovered that fish have an individual 'swimming personality', and that this personality influences their capability to respond efficiently to odors and find the source. Importantly, the personality traits that favored significant responses to odors were different in surface fish and cavefish. Moreover, the responses displayed by second-generation cave × surface F2 hybrids suggested that olfactory-driven behavior and olfactory sensitivity is a quantitative genetic trait. Our findings show that olfactory processing has rapidly evolved in cavefish at several levels: detection threshold, odor preference, and foraging behavior strategy. Cavefish is therefore an outstanding model to understand the genetic, molecular, and neurophysiological basis of sensory specialization in response to environmental change.

Pleistocene climate oscillations have shaped the expansion and contraction speciation model of the globose Eriosyce sect. Neoporteria cacti in Central Chile.

BACKGROUND AND AIMS: Pleistocene climatic oscillations, characterized by arid (interglacial) and pluvial (glacial) phases, have profoundly impacted the floras of Mediterranean climates. Our study investigates the hypothesis that these climatic extremes have promoted phases of range expansion and contraction in the Eriosyce sect. Neoporteria, resulting in pronounced genetic structuring and restricted gene flow. METHODS: Utilizing nuclear microsatellite markers, we genotyped 251 individuals across 18 populations, encompassing all 14 species and one subspecies within the Eriosyce sect. Neoporteria. Additionally, Species Distribution Models (SDMs) were employed to reconstruct past (Last Interglacial, Last Glacial Maximum, Mid-Holocene) and current potential distribution patterns, aiming to delineate the climatic influences on species' range dynamics. KEY RESULTS: The gene flow analysis disclosed disparate levels of genetic interchange among species, with marked restrictions observed between entities that are geographically or ecologically separated. Notably, E. subgibbosa from Hualpen emerged as genetically distinct, warranting its exclusion for clearer genetic clustering into north, central, and south clusters. The SDMs corroborated these findings, showing marked range expansions during warmer periods and contractions during colder times, indicating significant shifts in distribution patterns in response to climatic changes. CONCLUSIONS: Our findings emphasize the critical role of Pleistocene climatic fluctuations in driving the dynamic patterns of range expansions and contractions that have led to geographic isolation and speciation within the Eriosyce sect. Neoporteria. Even in the face of ongoing gene flow, these climate-driven processes have played a pivotal role in sculpting the species' genetic architecture and diversity. This study elucidates the complex interplay between climatic variability and evolutionary dynamics among Mediterranean cacti in central Chile, highlighting the necessity of considering historical climatic millenial oscillations in conservation and evolutionary biology studies.

Shining a light on Ohno's dilemma.

Laboratory experiments on a fluorescent protein in E. coli reveal how duplicate genes are rapidly inactivated by mutations during evolution.

A mitochondrial carrier transports glycolytic intermediates to link cytosolic and mitochondrial glycolysis in the human gut parasite Blastocystis.

Stramenopiles form a clade of diverse eukaryotic organisms, including multicellular algae, the fish and plant pathogenic oomycetes, such as the potato blight Phytophthora, and the human intestinal protozoan Blastocystis. In most eukaryotes, glycolysis is a strictly cytosolic metabolic pathway that converts glucose to pyruvate, resulting in the production of NADH and ATP (Adenosine triphosphate). In contrast, stramenopiles have a branched glycolysis in which the enzymes of the pay-off phase are located in both the cytosol and the mitochondrial matrix. Here, we identify a mitochondrial carrier in Blastocystis that can transport glycolytic intermediates, such as dihydroxyacetone phosphate and glyceraldehyde-3-phosphate, across the mitochondrial inner membrane, linking the cytosolic and mitochondrial branches of glycolysis. Comparative analyses with the phylogenetically related human mitochondrial oxoglutarate carrier (SLC25A11) and dicarboxylate carrier (SLC25A10) show that the glycolytic intermediate carrier has lost its ability to transport the canonical substrates malate and oxoglutarate. Blastocystis lacks several key components of oxidative phosphorylation required for the generation of mitochondrial ATP, such as complexes III and IV, ATP synthase, and ADP/ATP carriers. The presence of the glycolytic pay-off phase in the mitochondrial matrix generates ATP, which powers energy-requiring processes, such as macromolecular synthesis, as well as NADH, used by mitochondrial complex I to generate a proton motive force to drive the import of proteins and molecules. Given its unique substrate specificity and central role in carbon and energy metabolism, the carrier for glycolytic intermediates identified here represents a specific drug and pesticide target against stramenopile pathogens, which are of great economic importance.

All living organisms breakdown food molecules to generate energy for processes, such as growing, reproducing and movement. The series of chemical reactions that breakdown sugars into smaller molecules ­ known as glycolysis ­ is so important that it occurs in all life forms, from bacteria to humans. In higher organisms, such as fungi and animals, these reactions take place in the cytosol, the space surrounding the cell's various compartments. A transport protein then shuttles the end-product of glycolysis ­ pyruvate ­ into specialised compartments, known as the mitochondria, where most energy is produced. However, recently it was discovered that a group of living organisms, called the stramenopiles, have a branched glycolysis in which the enzymes involved in the second half of this process are located in both the cytosol and mitochondrial matrix. But it was not known how the intermediate molecules produced after the first half of glycolysis enter the mitochondria. To answer this question, Pyrihová et al. searched for transport protein(s) that could link the two halves of the glycolysis pathway. Computational analyses, comparing the genetic sequences of many transport proteins from several different species, revealed a new group found only in stramenopiles. Pyrihová et al. then used microscopy to visualise these new transport proteins ­ called GIC-1 and GIC-2 ­ in the parasite Blastocystis, which infects the human gut, and observed that they localise to mitochondria. Further biochemical experiments showed that GIC-1 and GIC-2 can physically bind these intermediate molecules, but only GIC-2 can transport them across membranes. Taken together, these observations suggest that GIC-2 links the two halves of glycolysis in Blastocystis. Further analyses could reveal corresponding transport proteins in other stramenopiles, many of which have devastating effects on agriculture, such as Phytophthora, which causes potato blight, or Saprolegnia, which causes skin infections in farmed salmon. Since human cells do not have equivalent transporters, they could be new drug targets not only for Blastocystis, but for these harmful pathogens as well.

CoCoNuTs are a diverse subclass of Type IV restriction systems predicted to target RNA.

A comprehensive census of McrBC systems, among the most common forms of prokaryotic Type IV restriction systems, followed by phylogenetic analysis, reveals their enormous abundance in diverse prokaryotes and a plethora of genomic associations. We focus on a previously uncharacterized branch, which we denote coiled-coil nuclease tandems (CoCoNuTs) for their salient features: the presence of extensive coiled-coil structures and tandem nucleases. The CoCoNuTs alone show extraordinary variety, with three distinct types and multiple subtypes. All CoCoNuTs contain domains predicted to interact with translation system components, such as OB-folds resembling the SmpB protein that binds bacterial transfer-messenger RNA (tmRNA), YTH-like domains that might recognize methylated tmRNA, tRNA, or rRNA, and RNA-binding Hsp70 chaperone homologs, along with RNases, such as HEPN domains, all suggesting that the CoCoNuTs target RNA. Many CoCoNuTs might additionally target DNA, via McrC nuclease homologs. Additional restriction systems, such as Type I RM, BREX, and Druantia Type III, are frequently encoded in the same predicted superoperons. In many of these superoperons, CoCoNuTs are likely regulated by cyclic nucleotides, possibly, RNA fragments with cyclic termini, that bind associated CARF (CRISPR-Associated Rossmann Fold) domains. We hypothesize that the CoCoNuTs, together with the ancillary restriction factors, employ an echeloned defense strategy analogous to that of Type III CRISPR-Cas systems, in which an immune response eliminating virus DNA and/or RNA is launched first, but then, if it fails, an abortive infection response leading to PCD/dormancy via host RNA cleavage takes over.

All organisms, from animals to bacteria, are subject to genetic parasites, such as viruses and transposons. Genetic parasites are pieces of nucleic acids (DNA or RNA) that can use a cell's machinery to copy themselves at the expense of their hosts. This often leads to the host's demise, so organisms evolved many types of defense mechanisms. One of the most ancient and common forms of defense against viruses and transposons is the targeted restriction of nucleic acids, that is, deployment of host enzymes that can destroy or restrict nucleic acids containing specific sequence motifs or modifications. In bacteria, many of the restriction enzymes targeting parasitic genetic elements are formed by fusions of proteins from the so-called McrBC systems with a protein domain called EVE. EVE and other functionally similar domains are a part of proteins that recognize and bind modified bases in nucleic acids. Enzymes can use the ability of these specificity domains to bind modified bases to detect non-host nucleic acids. Bell et al. conducted a comprehensive computational search for McrBC systems and discovered a large and highly diverse branch of this family with unusual characteristic structural and functional domains. These features include regions that form long alpha-helices (coils) that coil with other alpha-helices (known as coiled-coils), as well as several distinct enzymatic domains that break down nucleic acids (known as nucleases). They call these systems CoCoNuTs (coiled-coiled nuclease tandems). All CoCoNuTs contain domains, including EVE-like ones, which are predicted to interact with components of the RNA-based systems responsible for producing proteins in the cell (translation), suggesting that the CoCoNuTs have an important impact on protein abundance and RNA metabolism. Bell et al.'s findings will be of interest to scientists working on prokaryotic immunity and virulence. Furthermore, similarities between CoCoNuTs and components of eukaryotic RNA-degrading systems suggest evolutionary connections between this diverse family of bacterial predicted RNA restriction systems and RNA regulatory pathways of eukaryotes. Further deciphering the mechanisms of CoCoNuTs could shed light on how certain pathways of RNA metabolism and regulation evolved, and how they may contribute to advances in biotechnology.

Structural Power and Epistemologies in the Scientific Field: Why a Rapid Reconciliation Between Functional and Evolutionary Biology is Unlikely.

The past decade has been marked by a series of global crises, presenting an opportunity to reevaluate the relationship between science and politics. The biological sciences are instrumental in understanding natural phenomena and informing policy decisions. However, scholars argue that current scientific expertise often fails to account for entire populations and long-term impacts, hindering efforts to address issues such as biodiversity loss, global warming, and pandemics. This article explores the structural challenges of integrating an evolutionary perspective, historically opposed to functional determinants of health and disease, into current biological science practices. Using data on Swiss biology professors from 1957, 1980, and 2000, we examine the structural power dynamics that have led to the division between these competing epistemologies, and how this division has influenced resource allocation and career trajectories. Our analysis suggests that this cleavage presents a significant obstacle to achieving fruitful reconciliations, and that increased academicization and internationalization may benefit functional biologists at the expense of evolutionary biologists. While evolutionary biologists have gained symbolic recognition in recent years, this has not translated into valuable expertise in the political domain.

CLOCK evolved in cnidaria to synchronize internal rhythms with diel environmental cues.

The circadian clock enables anticipation of the day/night cycle in animals ranging from cnidarians to mammals. Circadian rhythms are generated through a transcription-translation feedback loop (TTFL or pacemaker) with CLOCK as a conserved positive factor in animals. However, CLOCK's functional evolutionary origin and mechanism of action in basal animals are unknown. In the cnidarian Nematostella vectensis, pacemaker gene transcript levels, including NvClk (the Clock ortholog), appear arrhythmic under constant darkness, questioning the role of NvCLK. Utilizing CRISPR/Cas9, we generated a NvClk allele mutant (NvClkΔ), revealing circadian behavior loss under constant dark (DD) or light (LL), while maintaining a 24 hr rhythm under light-dark condition (LD). Transcriptomics analysis revealed distinct rhythmic genes in wild-type (WT) polypsunder LD compared to DD conditions. In LD, NvClkΔ/Δ polyps exhibited comparable numbers of rhythmic genes, but were reduced in DD. Furthermore, under LD, the NvClkΔ/Δ polyps showed alterations in temporal pacemaker gene expression, impacting their potential interactions. Additionally, differential expression of non-rhythmic genes associated with cell division and neuronal differentiation was observed. These findings revealed that a light-responsive pathway can partially compensate for circadian clock disruption, and that the Clock gene has evolved in cnidarians to synchronize rhythmic physiology and behavior with the diel rhythm of the earth's biosphere.

The photo-protective role of vitamin D in the microalga Emiliania huxleyi.

An essential interaction between sunlight and eukaryotes involves vitamin D production through exposure to ultraviolet (UV) radiation. While extensively studied in vertebrates, the role of vitamin D in non-animal eukaryotes like microalgae remains unclear. Here, we investigate the potential involvement of vitamin D in the UV-triggered response of Emiliania huxleyi, a microalga inhabiting shallow ocean depths that are exposed to UV. Our results show that E. huxleyi produces vitamin D2 and D3 in response to UV. We further demonstrate that E. huxleyi responds to external administration of vitamin D at the transcriptional level, regulating protective mechanisms that are also responsive to UV. Our data reveal that vitamin D addition enhances algal photosynthetic performance while reducing harmful reactive oxygen species buildup. This study contributes to understanding the function of vitamin D in E. huxleyi and its role in non-animal eukaryotes, as well as its potential importance in marine ecosystems.