Human astroviruses are a common cause of viral gastroenteritis and are often underdiagnosed. While infections are typically mild or asymptomatic in immunocompetent hosts, astrovirus can cause prolonged and severe disease in immunocompromised individuals. Here, we conducted a case-control study to evaluate the clinical presentation of astrovirus infections in paediatric oncology patients. Our findings were compared to two groups: (1) norovirus infections in the same immunocompromised cohort, and (2) a cohort of immunocompetent children with and without diarrheal symptoms. Astrovirus was detected in 9.8% of immunocompromised patients, with prolonged shedding seen in multiple cases. Astrovirus infection was associated with an increased odds of diarrhoea, although this association weakened when adjusting for co-infections. In contrast, norovirus was not significantly associated with diarrhoea in immunocompromised patients, despite prolonged shedding in 24% of the cohort. High rates of co-infection with adenovirus and Clostridium difficile may have influenced symptom patterns. In the immunocompetent cohort, astrovirus was not associated with diarrhoea, while norovirus showed a strong association with symptoms. These findings indicate that astrovirus infections are more likely to cause diarrhoea in immunocompromised paediatric patients, while often asymptomatic in immunocompetent children. Norovirus showed the opposite trend, highlighting distinct roles of host immune status in shaping clinical outcomes. These findings highlight the importance of considering astrovirus as a potential contributor to gastrointestinal symptoms in immunocompromised children and call for broader diagnostic testing and further research on viral co-infections and persistence.
Bias in student teaching evaluations is a well-documented issue. As predicted in the literature, our campus found that changing questions to focus more on student direct observation and metacognitive reflection, as well changing to a frequency scale, was correlated with an increase in favorable ratings for instructors who are women or from under-represented populations. We compare data from a full year of an older question set to a full year of a revised question set. Our campus focuses on the percent of responses in the top two (of five) categories as a summary of student feedback. A logistic regression analysis shows that the gaps between populations of instructors change significantly over the time of the change in questions.
Microplastic (particles <5 mm) is an emerging environmental concern that threatens aquatic ecosystems worldwide. While extensive research has documented the ubiquity of microplastic in marine and coastal environments and its assimilation by organisms at all trophic levels, comparatively little is known about microplastic occurrence in rural riverine ecosystems. Even less information exists for salmon-bearing streams, where microplastic pollution may hinder salmonid conservation and recovery efforts. We examined the presence and concentration of microplastic in Scott Creek, a small coastal California (USA) watershed with minimal urban development. Our study quantified suspended microplastic in surface waters and in the gastrointestinal (GI) tracts of juvenile Steelhead Trout (Oncorhynchus mykiss). Microplastic was detected in 93 % of water samples, indicating that Scott Creek routinely transports and cycles microplastic. Concentrations were higher in late summer than in spring, although monthly spatial patterns were largely consistent among sites. In juvenile steelhead, 60.6 % of GI tracts contained one or more types of microplastic. For both surface waters and juvenile steelhead, microplastic was predominantly small (<5 mm) dark blue, black, and transparent fiber-type particles, with fragments, shards and foams encountered less frequently. These findings suggest that fish ingest microplastic at low frequencies, or that ingested particles may pass rapidly through their digestive systems. This study provides one of the first assessments of microplastic in a minimally urbanized, salmon-bearing watershed. Our results serve as a baseline for evaluating the ecological implications of microplastic pollution in small coastal creeks and its potential to influence native salmonid populations. Data Availability The surface water and steelhead microplastic datasets generated and analyzed during the current study are publicly available via Zenodo (DOI: 10.5281/zenodo.18038857).
Energy efficiency is a global priority, but investments in energy efficiency do not always deliver the expected benefits. This paper studies micro-irrigation systems (MIS), a technology thought to reduce the energy required for irrigation by as much as 70 percent. We installed individual meters to directly measure the energy consumption of several hundred farmers in Gujarat, India, and linked the meter data with survey data to yield a uniquely comprehensive view into energy use patterns in smallholder agriculture. We document two facts. One, energy use varies widely across farmers, and this variation is unexplained by factors such as farm area or village geography. Two, MIS users in our sample consume 30 to 40 percent more energy than non-users of MIS. This difference does not appear to be fully explained by observable differences across farmers nor by rebound effects, suggesting that the energy efficiency gains of MIS under real-world conditions may be disappointing. Our results highlight a need for increased attention to the details of implementation and further research into the actual benefits of resource-conserving technologies.
Cell motility is essential for processes such as immune responses, wound healing, and fertilization. Caenorhabditis elegans is an excellent model for studying sperm motility, due to the worm's transparency and high sperm production. C. elegans amoeboid sperm move by extending and retracting pseudopods, which are powered internally by the dynamic polymerization and depolymerization of the nematode Major Sperm Protein (MSP). Previous biochemical studies in the parasitic nematode Ascaris suum identified MSP polymerization-activating kinase (MPAK) as a key regulator of MSP assembly within the pseudopod. Here we investigate two C. elegans homologs, Tau Tubulin Kinase 8.1 (ttbk-8.1) and Tau Tubulin Kinase 8.2 (ttbk-8.2), that arose from a C. elegans-specific gene duplication. We generated both single and double knockout mutants; single knockout animals have fertility comparable to wildtype. Self-fertilizing double knockout (ttbk-8.1/2) hermaphrodites are severely sub-fertile, and males are completely infertile. ttbk-8.1/2 males successfully transfer sperm to females; however, their sperm cannot crawl to the site of fertilization. During sperm activation, ttbk-8.1/2 sperm undergo the two key events of sperm activation (membranous organelle fusion and pseudopod extension), however the process is abnormally slow. Furthermore, the resulting pseudopods are non-motile and abnormally smooth. Localization of key proteins to the pseudopods remains unaffected. TTBK-8.1/2 colocalizes with MSP to the fibrous bodies in mature spermatocytes, distributes throughout the cytoplasm in spermatids, and is confined to pseudopods of spermatozoa. These findings suggest an essential role for TTBK-8.1/2 in timely sperm activation and pseudopod motility.
All air-breathing marine vertebrates face the same fundamental trade-off: time spent foraging underwater must be offset by surface recovery between dives. For decades, the dominant view in diving physiology has been that post-dive duration (PDD) reflects the repayment of oxygen debt and clearance of carbon dioxide and lactate. Using more than 800 000 dives from five sea lion species across 18 colonies spanning tropical to subpolar waters, we quantified how PDD scales with dive depth and duration and evaluated whether this pattern is consistent with metabolic recovery interpretations or instead points to depth-linked constraints. We found that PDD increases primarily and linearly with depth, while dive duration contributes to PDD only at greater depths, a relationship conserved across species despite pronounced differences in body mass, dive physiology and foraging ecology. Our findings conflict with predictions of metabolic recovery interpretations and point to a pressure-linked mechanism in which time at depth and resulting inert-gas loading shape surface recovery. By highlighting pressure-linked inert-gas management as a central candidate mechanism for surface interval regulation in inhalation divers, our study revises a central assumption in diving physiology, with broad consequences for understanding foraging efficiency, habitat accessibility and vulnerability to environmental change in air-breathing marine vertebrates.
The term ‘ecosystem engineering’ refers to biotic processes that modulate the availability of resources to other species. These processes thus modify, maintain or create habitats and impact the abundance and diversity of species within ecosystems. In turn, the study of ecosystem engineering in the fossil record is leading to a re-evaluation of the influence of organisms on the deep-time evolution of Earth-system structure and function. With this comes a growing recognition that biological forces may be key drivers of major transitions in Earth history. There are two crucial questions: first, have new ecosystem engineering processes emerged randomly throughout geologic time, or are they clustered? Second, to what extent has their emergence driven episodes of evolutionary radiation or extinction? Here, we address these questions through the lens of the Ediacaran–Cambrian transition (∼575–530 million years ago) — an interval that witnessed the rapid rise of animals, following nearly four billion years of microbial dominance. We propose that an engineering regime shift occurred in the late Ediacaran that gave rise to new rules of community assembly, new ecological niches, and altered macroevolutionary trajectories. We argue that the recognition of ecosystem engineering regime shifts may help us not only to understand other key intervals in the Phanerozoic, but also to project the future of ecosystems under human influence.
It is unclear how serotonin 2A receptors (5-HT2ARs) in cortical layer 5 pyramidal neurons differentially contribute to psilocybin-induced hallucinations versus neuroplasticity. Here we show that psilocybin promotes synapse formation and maturation while accelerating the elimination of pre-existing synapses. Cell type-specific manipulation further demonstrated that 5-HT2AR signaling in cortical layer 5 pyramidal neurons is necessary and sufficient for psilocybin-induced synaptic remodeling but dispensable for the head-twitch response, a rodent proxy of hallucination.
Barrier epithelia are shielded from the external environment by their apical extracellular matrices (aECMs). The molecular complexity of aECMs has challenged understanding of their organization in vivo. To define the molecular architecture of a model aECM we generated a toolkit of 105 fluorescently tagged aECM components using gene editing in C. elegans, focusing on proteins secreted by the epidermis to form the collagen-rich cuticle. We developed efficient pipelines for modular protein tagging and rapid fluorophore swapping. Most tagged collagens were functional and exhibited exquisitely specific patterning across stages, cell types, and matrix substructures. We define multiple reference markers for key substructures including the little-understood cortical layer, as well as the helical crossed fiber arrays that function as a hydrostatic skeleton to maintain organismal shape. We further tagged 30 members of key aECM protein classes including proteases, protease inhibitors, and lipid transporters. Our standardized markers will allow dissection of the mechanistic basis of aECM spatiotemporal patterning in vivo.
