bluuebunny/crossref_metadata_2025 huggingface dataset:
MR Imaging Patterns and Prognosis in Powassan Virus Encephalitis
Authors: Finelli Pasquale F.
Published: October 2023

Background:

Powassan virus (POWV) encephalitis is an arbovirus infection and the only tick-borne encephalitis serogroup which is present in mainland North America. The magnetic resonance (MR) imaging described with POWV encephalitis is varied, nonspecific, and limited in number, and as such, imaging patterns and outcomes with this arbovirus infection are not well appreciated.

Methods:

A case report and literature review of the MR imaging associated with POWV encephalitis and correlate of the MR pattern with outcome is considered.

Results:

The cerebellar dominant MR imaging pattern was identified in 50% of POWV encephalitis cases and was associated with a 60% fatality rate. POWV encephalitis with prominent cerebellar involvement on MR imaging responded to intravenous steroid.

Conclusions:

A cerebellar dominant MR pattern in POWV encephalitis was common, associated with a poor prognosis, and recognition could change management from supportive to life-saving.
Uric Acid Nephropathy Secondary to Generalized Tonic-Clonic Seizures
Authors: Simon Amanda , Nguyen Dan , Newman Blake , Arain Amir
Published: October 2023

Introduction:

Acute kidney injury is a well-known complication of generalized tonic-clonic seizures, most commonly due to rhabdomyolysis. Elevated serum uric acid resulting in uric acid nephropathy is an overlooked cause of acute kidney injury in these patients, with only a few published case reports.

Case Report:

In the first case, a 23-year-old male was admitted with status epilepticus. His kidney function worsened and he developed anuria. He had a serum uric acid level of 20.7 mg/dL and required multiple sessions of hemodialysis. In the second case, a 32-year-old male was admitted with acute kidney injury after experiencing a breakthrough seizure. He had a serum uric acid level of 20.4 mg/dL and was treated with rasburicase with recovery of renal function. In the third case, a 29-year-old male was admitted with status epilepticus. His renal function deteriorated. His serum uric acid level was 19.5 mg/dL. He required hemodialysis and rasburicase.

Conclusion:

Uric acid nephropathy is a rare complication of generalized tonic-clonic seizures, which is poorly recognized by healthcare providers. We advocate for Nephrology consultation early in a patient’s hospitalization to discuss the use of rasburicase to avoid the associated morbidity of renal replacement therapies.
Reverse Flow Thromboembolism From Distal Subclavian Artery Aneurysm Due to Arterial Thoracic Outlet Syndrome and Posterior Circulation Stroke-Role of Dynamic Doppler Imaging
Authors: Kumar Adarsh Anil , Kannath Santhosh Kumar , Thomas Bejoy , PN Sylaja , P Shivanesan , Surendran Manju
Published: October 2023

Introduction:

Arterial thoracic outlet syndrome (aTOS) is the least common among the 3 subtypes of thoracic outlet syndrome and can be the cause of posterior circulation infarction due to thrombus from a secondary thrombosed subclavian-axillary artery aneurysm.

Case Report:

Here, we report a case of a 51-year-old man who presented to our institute with sudden onset vertigo, dizziness, vomiting, gait imbalance, and visual field defects immediately after strenuous exercise. Computed tomography angiography revealed bilateral cervical ribs with aneurysmal dilatation of the left distal subclavian and proximal axillary arteries. The computed tomography also revealed subacute infarcts in the bilateral cerebellar hemispheres, as well as in the bilateral occipital lobes. Color Doppler evaluation of the subclavian artery after hyperabduction of the ipsilateral arm revealed a continuous reversal of flow in the subclavian artery, which reached the vertebral ostia. The left cervical rib was resected, aneurysm was repaired, and the patient remained asymptomatic on follow-up.

Conclusion:

Posterior circulation stroke caused by the ipsilateral thrombosed subclavian artery aneurysm in an adult patient with aTOS due to a complete cervical rib is rare. A high index of suspicion should be present for thoracic outlet syndrome in patients with stroke and upper-limb arterial claudication symptoms. Dynamic Doppler evaluation in such patients can be used to demonstrate the underlying pathomechanism, and definitive surgical treatment can prevent further ischemic episodes. Posterior circulation stroke caused by partially thrombosed distal subclavian and axillary artery aneurysms due to aTOS is rare.
Increased 18F-FAPI-04 Uptake in Vertebral Hemangioma
Authors: Ren Jing-Yun , Zhang Qing , Wang Peng , Jiang Lei , Liu En-Tao
Published: October 2023

A 54-year-old man with a history of colectomy for colorectal cancer and subsequent liver metastasectomy underwent 18F-FDG PET/CT and 18F-FAPI-04 PET/CT scans to evaluate possible hepatic metastasis revealed by contrast-enhanced MRI. Both studies showed similarly increased uptake in liver metastases, and 18F-FDG detected a metastatic lung nodule. Furthermore, the images showed an incidental finding of increased uptake of 18F-FAPI-04 in the L3 vertebral, which was not 18F-FDG–avid. A review of the patient's previous CT and MRI scans suggests vertebral hemangioma.
Rhythmic chew cycles with distinct fast and slow phases are ancestral to gnathostomes
Authors: Richard Brian A. , Spence Meghan , Rull-Garza Mateo , Roba Yonas Tolosa , Schwarz Daniel , Ramsay Jason B. , Laurence-Chasen J. D. , Ross Callum F. , Konow Nicolai
Published: October 2023

Intra-oral food processing, including chewing, is important for safe swallowing and efficient nutrient assimilation across tetrapods. Gape cycles in tetrapod chewing consist of four phases (fast open and -close, and slow open and -close), with processing mainly occurring during slow close. Basal aquatic-feeding vertebrates also process food intraorally, but whether their chew cycles are partitioned into distinct phases, and how rhythmic their chewing is, remains unknown. Here, we show that chew cycles from sharks to salamanders are as rhythmic as those of mammals, and consist of at least three, and often four phases, with phase distinction occasionally lacking during jaw opening. In fishes and aquatic-feeding salamanders, fast open has the most variable duration, more closely resembling mammals than basal amniotes (lepidosaurs). Across ontogenetically or behaviourally mediated terrestrialization, salamanders show a distinct pattern of the second closing phase (near-contact) being faster than the first, with no clear pattern in partitioning of variability across phases. Our results suggest that distinct fast and slow chew cycle phases are ancestral for jawed vertebrates, followed by a complicated evolutionary history of cycle phase durations and jaw velocities across fishes, basal tetrapods and mammals. These results raise new questions about the mechanical and sensorimotor underpinnings of vertebrate food processing.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Do salamanders chew? An X-ray reconstruction of moving morphology analysis of ambystomatid intraoral feeding behaviours
Authors: Spence Meghan , Rull-Garza Mateo , Roba Yonas Tolosa , Konow Nicolai
Published: October 2023

Chewing is widespread across vertebrates, including mammals, lepidosaurs, and ray-finned and cartilaginous fishes, yet common wisdom about one group—amphibians—is that they swallow food whole, without processing. Earlier salamander studies lacked analyses of internal kinematics of the tongue, analyses of muscle function, and sampled few individuals, which may have caused erroneous conclusions. Specifically, without tongue and food kinematics, intraoral behaviours are difficult to disambiguate. We hypothesized that ambystomatid salamanders use diverse intraoral behaviours, including chewing, and tested this hypothesis with biplanar videofluoroscopy, X-ray reconstruction of moving morphology, and fluoromicrometry. We generated musculoskeletal kinematic profiles for intraoral behaviours in Axolotls (Ambystoma mexicanum), including three-dimensional skeletal kinematics associated with feeding, for gape, cranial and pectoral girdle rotations, and tongue translations. We also measured muscle fibre and muscle–tendon unit strains for six muscles involved in generating skull, jaw and tongue kinematics (adductor mandibulae, depressor mandibulae, geniohyoid, sternohyoid, epaxialis and hypaxialis). A principal component analysis recovered statistically significant differences between behaviour cycles, classified based on food movements as either chewing or transport. Thus, our data suggest that ambystomatid salamanders use a previously unrecognized diversity of intraoral behaviours, including chewing. Combined with existing knowledge, our data suggest that chewing is a basal trait for tetrapods and jaw-bearing vertebrates.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Using salamanders as model taxa to understand vertebrate feeding constraints during the late Devonian water-to-land transition
Authors: Schwarz Daniel , Heiss Egon , Pierson Todd W. , Konow Nicolai , Schoch Rainer R.
Published: October 2023

The vertebrate water-to-land transition and the rise of tetrapods brought about fundamental changes for the groups undergoing these evolutionary changes (i.e. stem and early tetrapods). These groups were forced to adapt to new conditions, including the distinct physical properties of water and air, requiring fundamental changes in anatomy. Nutrition (or feeding) was one of the prime physiological processes these vertebrates had to successfully adjust to change from aquatic to terrestrial life. The basal gnathostome feeding mode involves either jaw prehension or using water flows to aid in ingestion, transportation and food orientation. Meanwhile, processing was limited primarily to simple chewing bites. However, given their comparatively massive and relatively inflexible hyobranchial system (compared to the more muscular tongue of many tetrapods), it remains fraught with speculation how stem and early tetrapods managed to feed in both media. Here, we explore ontogenetic water-to-land transitions of salamanders as functional analogues to model potential changes in the feeding behaviour of stem and early tetrapods. Our data suggest two scenarios for terrestrial feeding in stem and early tetrapods as well as the presence of complex chewing behaviours, including excursions of the jaw in more than one dimension during early developmental stages. Our results demonstrate that terrestrial feeding may have been possible before flexible tongues evolved.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Food transport in Reptilia: a comparative viewpoint
Authors: Bels Vincent , Le Floch Glenn , Kirchhoff Florence , Gastebois Gilbert , Davenport John , Baguette Michel
Published: October 2023

Reptilia exploit a large diversity of food resources from plant materials to living mobile prey. They are among the first tetrapods that needed to drink to maintain their water homeostasis. Here were compare the feeding and drinking mechanisms in Reptilia through an empirical approach based on the available data to open perspectives in our understanding of the evolution of the various mechanisms determined in these Tetrapoda for exploiting solid and liquid food resources.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Warmer ambient temperatures reduce protein intake by a mammalian folivore
Authors: Beale Phillipa K. , Foley William J. , Moore Ben D. , Marsh Karen J.
Published: October 2023

The interplay between ambient temperature and nutrition in wild herbivores is frequently overlooked, despite the fundamental importance of food. We tested whether different ambient temperatures (10°C, 18°C and 26°C) influenced the intake of protein by a marsupial herbivore, the common brushtail possum (
Trichosurus vulpecula
). At each temperature, possums were offered a choice of two foods containing different amounts of protein (57% versus 8%) for one week. Animals mixed a diet with a lower proportion of protein to non-protein (P : NP, 0.20) when held at 26°C compared to that at both 10°C and 18°C (0.22). Since detoxification of plant secondary metabolites imposes a protein cost on animals, we then studied whether addition of the monoterpene 1,8-cineole to the food changed the effect of ambient temperature (10°C and 26°C) on food choice. Cineole reduced food intake but also removed the effect of temperature on P : NP ratio and instead animals opted for a diet with higher P : NP (0.19 with cineole versus 0.15 without cineole). These experiments show the proportion of P : NP chosen by animals is influenced by ambient temperature and by plant secondary metabolites. Protein is critical for reproductive success in this species and reduced protein intake caused by high ambient temperatures may limit the viability of some populations in the future.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Teeth and the gastrointestinal tract in mammals: when 1 + 1 = 3
Authors: Clauss Marcus , Fritz Julia , Hummel Jürgen
Published: October 2023

Both teeth and the digestive tract show adaptations that are commonly interpreted in the context of trophic guilds—faunivory, herbivory and omnivory. Teeth prepare food for the digestive tract, and dental evolution focuses on increasing durability and functionality; in particular, size reduction of plant particles is an important preparation for microbial fermentative digestion. In narratives of digestive adaptations, microbes are typically considered as service providers, facilitating digestion. That the majority of ‘herbivorous’ (and possibly ‘omnivorous’) mammals display adaptations to maximize microbes' use as prey—by harvesting the microbes multiplying in their guts—is less emphasized and not reflected in trophic labels. Harvesting of microbes occurs either via coprophagy after separation from indigestible material by a separation mechanism in the hindgut, or from a forestomach by a ‘washing mechanism’ that selectively removes fines, including microbes, to the lower digestive tract. The evolution of this washing mechanism as part of the microbe farming niche opened the opportunity for the evolution of another mechanism that links teeth and guts in an innovative way—the sorting and cleaning of not-yet-sufficiently-size-reduced food that is then re-submitted to repeated mastication (rumination), leading to unprecedented chewing and digestive efficiency.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Towards an integrated understanding of dietary phenotypes
Authors: Raubenheimer David , Hou Rong , Dong Yunlong , Ren Cuiru , Cui Zhenwei
Published: October 2023

Diet and nutrition comprise a complex, multi-faceted interface between animal biology and food environments. With accumulating information on the many facets of this association arises a need for systems-based approaches that integrate dietary components and their links with ecology, feeding, post-ingestive processes and the functional and ecological consequences of these interactions. We briefly show how a modelling approach, nutritional geometry, has used the experimental control afforded in laboratory studies to begin to unravel these links. Laboratory studies, however, have limited ability to establish whether and how the feeding and physiological mechanisms interface with realistic ecological environments. We next provide an overview of observational field studies of free-ranging primates that have examined this, producing largely correlative data suggesting that similar feeding mechanisms operate in the wild as in the laboratory. Significant challenges remain, however, in establishing causal links between feeding, resource variation and physiological processes in the wild. We end with a more detailed account of two studies of temperate primates that have capitalized on the discrete variation provided by seasonal environments to strengthen causal inference in field studies and link patterns of intake to dynamics of nutrient processing.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Three-dimensional kinematics of leaf-cutter ant mandibles: not all dicondylic joints are simple hinges
Authors: Kang Victor , Püffel Frederik , Labonte David
Published: October 2023

Insects use their mandibles for a variety of tasks, including food processing, material transport, nest building, brood care, and fighting. Despite this functional diversity, mandible motion is typically thought to be constrained to rotation about a single fixed axis. Here, we conduct a direct quantitative test of this ‘hinge joint hypothesis’ in a species that uses its mandibles for a wide range of tasks:Atta vollenweiderileaf-cutter ants. Mandible movements from live restrained ants were reconstructed in three dimensions using a multi-camera rig. Rigid body kinematic analyses revealed strong evidence that mandible movement occupies a kinematic space that requires more than one rotational degree of freedom: at large opening angles, mandible motion is dominated by yaw. But at small opening angles, mandibles both yaw and pitch. The combination of yaw and pitch allows mandibles to ‘criss-cross’: either mandible can be on top when mandibles are closed. We observed criss-crossing in freely cutting ants, suggesting that it is functionally important. Combined with recent reports on the diversity of joint articulations in other insects, our results show that insect mandible kinematics are more diverse than traditionally assumed, and thus worthy of further detailed investigation.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Biomechanics of cutting: sharpness, wear sensitivity and the scaling of cutting forces in leaf-cutter ant mandibles
Authors: Püffel Frederik , Walthaus O. K. , Kang Victor , Labonte David
Published: October 2023

Herbivores large and small need to mechanically process plant tissue. Their ability to do so is determined by two forces: the maximum force they can generate, and the minimum force required to fracture the plant tissue. The ratio of these forces determines the relative mechanical effort; how this ratio varies with animal size is challenging to predict. We measured the forces required to cut thin polymer sheets with mandibles from leaf-cutter ant workers which vary by more than one order of magnitude in body mass. Cutting forces were independent of mandible size, but differed by a factor of two between pristine and worn mandibles. Mandibular wear is thus likely a more important determinant of cutting force than mandible size. We rationalize this finding with a biomechanical analysis, which suggests that pristine mandibles are ideally ‘sharp’—cutting forces are close to a theoretical minimum, which is independent of tool size and shape, and instead solely depends on the geometric and mechanical properties of the cut tissue. The increase of cutting force due to mandibular wear may be particularly problematic for small ants, which generate lower absolute bite forces, and thus require a larger fraction of their maximum bite force to cut the same plant.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Dynamic finite element modelling of the macaque mandible during a complete mastication gape cycle
Authors: Panagiotopoulou Olga , Robinson Dale , Iriarte-Diaz Jose , Ackland David , Taylor Andrea B. , Ross Callum F.
Published: October 2023

Three-dimensional finite element models (FEMs) are powerful tools for studying the mechanical behaviour of the feeding system. Using validated, static FEMs we have previously shown that in rhesus macaques the largest food-related differences in strain magnitudes during unilateral postcanine chewing extend from the lingual symphysis to the endocondylar ridge of the balancing-side ramus. However, static FEMs only model a single time point during the gape cycle and probably do not fully capture the mechanical behaviour of the jaw during mastication. Bone strain patterns and moments applied to the mandible are known to vary during the gape cycle owing to variation in the activation peaks of the jaw-elevator muscles, suggesting that dynamic models are superior to static ones in studying feeding biomechanics. To test this hypothesis, we built dynamic FEMs of a complete gape cycle using muscle force data from
in vivo
experiments to elucidate the impact of relative timing of muscle force on mandible biomechanics. Results show that loading and strain regimes vary across the chewing cycle in subtly different ways for different foods, something which was not apparent in static FEMs. These results indicate that dynamic three-dimensional FEMs are more informative than static three-dimensional FEMs in capturing the mechanical behaviour of the jaw during feeding by reflecting the asymmetry in jaw-adductor muscle activations during a gape cycle.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Gape drives regional variation in temporalis architectural dynamics in tufted capuchins
Authors: Laird Myra F. , Iriarte-Diaz Jose , Byron Craig D. , Granatosky Michael C. , Taylor Andrea B. , Ross Callum F.
Published: October 2023

Dynamic changes in jaw movements and bite forces depend on muscle architectural and neural factors that have rarely been compared within the same muscle. Here we investigate how regional muscle architecture dynamics—fascicle rotation, shortening, lengthening and architectural gear ratio (AGR)—vary during chewing across a functionally heterogeneous muscle. We evaluate whether timing in architecture dynamics relates to gape, food material properties and/or muscle activation. We also examine whether static estimates of temporalis fibre architecture track variation in dynamic architecture. Fascicle-level architecture dynamics were measured in three regions of the superficial temporalis of three adult tufted capuchins (
Sapajus apella
) using biplanar videoradiography and the XROMM workflow. Architecture dynamics data were paired with regional fine-wire electromyography data from four adult tufted capuchins. Gape accounted for most architectural change across the temporalis, but architectural dynamics varied between regions. Mechanically challenging foods were associated with lower AGRs in the anterior region. The timing of most dynamic architectural changes did not vary between regions and differed from regional variation in static architecture. Collectively these findings suggest that, when modelling temporalis muscle force production in extant and fossil primates, it is important to account for the effects of gape, regionalization and food material properties.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Energetic costs of feeding in 12 species of small-bodied primates
Authors: Wall Christine E. , Hanna Jandy B. , O'Neill Matthew C. , Toler Maxx , Laird Myra F.
Published: October 2023

There are no comparative, empirical studies of the energetic costs of feeding in mammals. As a result, we lack physiological data to better understand the selection pressures on the mammalian feeding apparatus and the influence of variables such as food geometric and material properties. This study investigates interspecific scaling of the net energetic costs of feeding in relation to body size, jaw-adductor muscle mass and food properties in a sample of 12 non-human primate species ranging in size from 0.08 to 4.2 kg. Net energetic costs during feeding were measured by indirect calorimetry for a variety of pre-cut and whole raw foods varying in geometric and material properties. Net feeding costs were determined in two ways: by subtracting either the initial metabolic rate prior to feeding or subtracting the postprandial metabolic rate. Interspecific scaling relationships were evaluated using pGLS and OLS regression. Net feeding costs scale negatively relative to both body mass and jaw-adductor mass. Large animals incur relatively lower feeding costs indicating that small and large animals experience and solve mechanical challenges in relation to energetics in different ways.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Evolution, diversification and function of the maternal–infant dyad in mammalian feeding
Authors: Mayerl Christopher J. , German Rebecca Z.
Published: October 2023

The evolution of the mother/infant dyad providing a source of nutrition for infants is essential for the origin and subsequent diversification of mammals. Despite the importance of this dyad, research on maternal and infant function is often treated independently. Our goal is to synthesize the work on maternal and infant function, discuss our own studies of suckling, and compare the origins of lactation and suckling with their ensuing diversification. Our central premise is that while extensive work has demonstrated variation across mammals in the maternal aspect of this system, very little has been done to address how this relates to infant function. We start with a discussion of the fundamental anatomy and physiology of both mother and infant. We next discuss the
origin
of mammary glands and milk, and infant suckling, which is distinct from their subsequent
diversification.
We then discuss the diversification of maternal and infant function, highlighting the evolutionary diversity present in maternal function (both anatomically and physiologically), before arguing that the diversity of infant function is unexplored, and needs to be better studied in the future. We end by discussing some of the holes in our understanding, and suggestions for future work that can address these lacunae.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Characterizing tongue deformations during mastication using changes in planar components of three-dimensional angles
Authors: Olson Rachel A. , Montuelle Stephane J. , Williams Susan H.
Published: October 2023

Understanding of tongue deformations during mammalian mastication is limited, but has benefited from recent developments in multiplanar imaging technology. Here, we demonstrate how a standardized radiopaque marker implant configuration and biplanar fluoroscopy can quantify three-dimensional shape changes during chewing in pigs. Transverse and sagittal components of the three-dimensional angle between markers enable characterizing deformations in anatomically relevant directions. The transverse component illustrates bending to the left or to the right, which can occur symmetrically or asymmetrically, the latter sometimes indicating regional widening. The sagittal component reflects ‘arching’ or convex deformations in the dorsoventral dimension symmetrically or asymmetrically, the latter characteristic of twisting. Trends are detected in both the transverse and sagittal planes, and combinations thereof, to modify tongue shape in complex deformations. Both the transverse and sagittal components were also measured at key jaw and tongue positions, demonstrating variability particularly with respect to maximum and minimum gape. This highlights the fact that unlike tongue position, tongue deformations are more independent of jaw position, likely in response to the ever-changing bolus shape and position. From a methodological perspective, our study showcases advantages of a repeatable three-marker implant configuration suitable for animals of different sizes and highlights considerations for different implant patterns.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
The feeding apparatus of ants: an overview of structure and function
Authors: Richter Adrian , Economo Evan P.
Published: October 2023

Ants are a dominant family of eusocial terrestrial insects with a diversity of ecologies, lifestyles and morphologies. Ant diet preferences range from strict carnivory through omnivory to almost complete herbivory in species feeding on seeds or exudates of plant-sucking insects. While several studies have investigated ant feeding performance on different substrates, comparatively little is known about the functional morphology of the structures involved in food uptake or their diversification across the ants. To take stock of our current knowledge, we give an overview of how adult ants ingest food, followed by a morphological description of the mouthparts, preoral space and cephalic sucking pump. The mandibles are the most prominent mouthparts and have received considerable attention in the literature, so we focus on the maxillae and labium here. We present current hypotheses for the movement patterns of these parts and discuss morphological differences among ants that may be related to their ecological diversity. Finally, we give short comparisons of the ant condition with some other insects and vertebrates, as well as an outlook summarizing gaps in our knowledge. This sets the stage for future studies elucidating the connections between ant feeding mechanisms and mouthpart evolution.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Introduction: food processing and nutritional assimilation in animals
Authors: Laird Myra F. , Ross Callum F. , Kang Victor , Konow Nicolai
Published: October 2023

How animals process and absorb nutrients from their food is a fundamental question in biology. Despite the continuity and interaction between intraoral food processing and post-oesophageal nutritional extraction, these topics have largely been studied separately. At present, we lack a synthesis of how pre- and post-oesophageal mechanisms of food processing shape the ability of various taxa to effectively assimilate nutrients from their diet. The aim of this special issue is to catalyse a unification of these distinct approaches as a functional continuum. We highlight questions that derive from this synthesis, as well as technical advances to address these questions. At present, there is also a skew toward vertebrates in studies of feeding form–function mechanics; by including perspectives from researchers working on both vertebrates and invertebrates, we hope to stimulate integrative and comparative research on food processing and nutritional assimilation. Below, we discuss how the papers in this issue contribute to these goals in three areas: championing a functional-comparative approach, quantifying performance and emphasizing the effects of life history, and food substrate and extrinsic factors in current and future studies of oral food processing and nutritional assimilation.

This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.
Secretory Leukocyte Protease Inhibitor Protects Against Severe Urinary Tract Infection in Mice
Authors: Rosen Anne L. , Lint Michael A. , Voelker Dayne H. , Gilbert Nicole M. , Tomera Christopher P. , Santiago-Borges Jesús , Wallace Meghan A. , Hannan Thomas J. , Burnham Carey-Ann D. , Hultgren Scott J. , Kau Andrew L.
Published: October 2023

Millions suffer from urinary tract infections (UTIs) worldwide every year with women accounting for the majority of cases. UropathogenicEscherichia coli(UPEC) causes most of these primary infections and leads to 25% becoming recurrent or chronic. To repel invading pathogens, the urinary tract mounts a vigorous innate immune response that includes the secretion of antimicrobial peptides (AMPs), rapid recruitment of phagocytes and exfoliation of superficial umbrella cells. Here, we investigate secretory leukocyte protease inhibitor (SLPI), an AMP with antiprotease, antimicrobial and immunomodulatory functions, known to play protective roles at other mucosal sites, but not well characterized in UTIs. Using a mouse model of UPEC-caused UTI, we show that urine SLPI increases in infected mice and that SLPI is localized to bladder epithelial cells. UPEC infected SLPI-deficient (Slpi-/-) mice suffer from higher urine bacterial burdens, prolonged bladder inflammation, and elevated urine neutrophil elastase (NE) levels compared to wild-type (Slpi+/+) controls. Combined with bulk bladder RNA sequencing, our data indicate thatSlpi-/-mice have a dysregulated immune and tissue repair response following UTI. We also measure SLPI in urine samples from a small group of female subjects 18-49 years old and find that SLPI tends to be higher in the presence of a uropathogen, except in patients with history of recent or recurrent UTI (rUTI), suggesting a dysregulation of SLPI expression in these women. Taken together, our findings show SLPI protects against acute UTI in mice and provides preliminary evidence that SLPI is likewise regulated in response to uropathogen exposure in women.
PCSK9 inhibition protects mice from food allergy
Authors: Lorant Victoria , Klein Martin , Garçon Damien , Sotin Thibaud , Frey Samuel , Cheminant Marie-Aude , Ayer Audrey , Croyal Mikaël , Flet Laurent , Colas Luc , Cariou Bertrand , Bouchaud Grégory , Le May Cédric
Published: October 2023

The Proprotein Convertase Subtilisin Kexin of type 9 (PCSK9) has been identified in 2003 as the third gene involved in familial hypercholesterolemia. PCSK9 binds to the membrane low-density lipoprotein receptor (LDLR) and promotes its cellular internalization and lysosomal degradation. Beyond this canonical role, PCSK9 was recently described to be involved in several immune responses. However, to date, the contribution of PCSK9 in food allergy remains unknown. Here, we showed thatPcsk9deficiency or pharmacological inhibition of circulating PCSK9 with a specific monoclonal antibody (m-Ab) protected mice against symptoms of gliadin-induced-food allergy, such as increased intestinal transit time and ear oedema. Furthermore, specific PCSK9 inhibition during the elicitation steps of allergic process was sufficient to ensure anti-allergic effects in mice. Interestingly, the protective effect of PCSK9 inhibition against food allergy symptoms was independent of the LDLR as PCSK9 inhibitors remained effective inLdlrdeficient mice.In vitro, we showed that recombinant gain of function PCSK9 (PCSK9 D374Y) increased the percentage of mature bone marrow derived dendritic cells (BMDCs), promoted naïve T cell proliferation and potentiated the gliadin induced basophils degranulation. Altogether, our data demonstrate that PCSK9 inhibition is protective against gliadin induced food allergy in a LDLR-independent manner.
Pervasive Influence of Hormonal Contraceptives on the Human Plasma Proteome in a Broad Population Study
Authors: Dordevic Nikola , Dierks Clemens , Hantikainen Essi , Farztdinov Vadim , Amari Fatma , Verri Hernandes Vinicius , De Grandi Alessandro , Domingues Francisco S. , Mülleder Michael , Pramstaller Peter Paul , Rainer Johannes , Ralser Markus
Published: October 2023

Background

Plasma proteomics offers new avenues to explore non-genetic associations, such as biomarkers for lifestyle and environmental exposure in population studies. To date, most proteomic investigations in population studies have utilized affinity-reagent based technologies, which are ideal to quantify the low abundant fraction of the circulating proteome but may omit several of the abundant proteins that function in plasma.

Methods

Utilizing high throughput mass spectrometry, we quantified 148 highly abundant protein groups including immunoglobulins, coagulation factors, metabolic proteins, and components of the innate immune system, in the plasma of 3,632 participants from the Cooperative Health Research in South Tyrol (CHRIS) study. Using multiple regression analyses we then investigated associations with various factors including common medications.

Results

Beyond age and sex, the high abundant plasma proteome is predominantly influenced by hormonal contraceptives. For instance, Angiotensinogen (AGT) levels exhibit significant alteration with this treatment, suggesting that AGT levels could be a potential biomarker for contraceptive use. The effect of this drug class is more pronounced than other common medications or covariates. Furthermore, our analysis does not reveal any enduring signature associated with the use of these contraceptives.

Conclusion

In contrast to most used drugs, hormonal contraceptives exert a pronounced effect on the high abundant plasma proteome. Given its high prevalence among young female participants, the impact of hormonal contraceptives might be misconstrued as sex-or age-related effects on the plasma proteome. One should thus account for their use in any epidemiological or clinical plasma proteome study to prevent misleading results.
A visual efference copy-based navigation algorithm inDrosophilafor complex visual environments
Authors: Canelo Angel , Kim Yeon , Park Jeongmin , Kim Anmo J
Published: October 2023

Drosophilavisuomotor processing has been intensively studied in recent years, leading to a qualitative understanding of individual neural circuits. However, the collective operation of these circuits during naturalistic behaviors, in which flies encounter a mixture of complex visual stimuli—including those caused by their own actions—remains unexplored. In this study, we developed an integrative model ofDrosophilavisuomotor processing, wherein multiple visuomotor circuits interconnect through an efference copy (EC) mechanism. To derive the model experimentally, we analyzed the wingbeat responses of flyingDrosophilato individual, rotating visual patterns. We then combined these models to build an integrative model for superposed visual patterns, using three different strategies: the addition-only, the graded EC, and the all-or-none EC models. We compared orientation behaviors of these models with those of flyingDrosophilathat rotates their body freely in response to complex visual patterns. Results of these experiments support the all-or-none EC model, in which the amplitude of the flight turn is unimpeded by the background scene, irrespective of the visual environment. Together, our “virtual fly” model provides a formal description of vision-based navigation strategies ofDrosophilain complex visual environments and offers a novel framework for assessing the role of constituent visuomotor neural circuits in real-world contexts.
Scarring hair follicle destruction is driven by the collapse of EGFR-protected JAK-STAT1-sensitive stem cell immune privilege
Authors: Strobl Karoline , Klufa Jörg , Jin Regina , Artner-Gent Lena , Krauß Dana , Novoszel Philipp , Strobl Johanna , Stary Georg , Vujic Igor , Griss Johannes , Holcmann Martin , Farlik Matthias , Homey Bernhard , Sibilia Maria , Bauer Thomas
Published: October 2023

The hair follicle stem cell niche is an immune-privileged microenvironment, characterised by suppressed antigen presentation, thus shielding against permanent immune-mediated tissue damage. In this study, we demonstrate the protective role of hair follicle-specific epidermal growth factor receptor (EGFR) from scarring hair follicle degeneration. Mechanistically, disruption of EGFR signalling generates a cell intrinsic hypersensitivity within the JAK-STAT1 pathway, compromising the immune privilege in the context of CD8 T cell and NK cell-mediated inflammation. Genetic depletion of either JAK1/2 or STAT1 or topical therapeutic inhibition of JAK1/2 restores the immune privilege and activates stem cells to resume hair growth in mouse models of epidermal and hair follicle specific EGFR deletion. Skin biopsies from EGFR inhibitor-treated and from EGFR-independent cicatricial alopecia patients indicate active STAT1 signalling within the hair follicles. Notably, a case study of folliculitis decalvans, characterised by progressive hair loss, scaling and perifollicular erythema, demonstrates successful treatment with systemic JAK1/2 inhibition. Our findings offer mechanistic insights and present a therapeutic strategy for addressing scarring hair follicle destruction associated with EGFR-inhibitor therapy and cicatricial alopecia.
Extraordinary levels of per- and polyfluoroalkyl substances (PFAS) in vertebrate animals at a New Mexico desert oasis: multiple pathways for wildlife and human exposure
Authors: Witt Christopher C. , Gadek Chauncey R. , Cartron Jean-Luc E. , Andersen Michael J. , Campbell Mariel L. , Castro-Farías Marialejandra , Gyllenhaal Ethan F. , Johnson Andrew B. , Malaney Jason L. , Montoya Kyana N. , Patterson Andrew , Vinciguerra Nicholas T. , Williamson Jessie L. , Cook Joseph A. , Dunnum Jonathan L.
Published: October 2023

Per- and polyfluoroalkyl substances (PFAS) threaten human and wildlife health, but their movement through food webs remains poorly understood. Contamination of the physical environment is widespread, but particularly concentrated at military installations. Here we measured 17 PFAS in wild, free-living mammals and migratory birds at Holloman Air Force Base (AFB), New Mexico, USA, where wastewater catchment lakes form biodiverse oases. PFAS concentrations were among the highest ever reported in animal tissues, and high levels have persisted for at least three decades. The hazardous long carbon-chain form, perfluorooctanosulfonic acid (PFOS), was most abundant, with liver concentrations averaging tens of thousands of ng/g wet weight (ww), reaching as high 97,000 ng/g (ww) in a 1994 specimen of white-footed mouse (Peromyscus leucopus) and 38,000 ng/g ww in a duck, the American wigeon (Mareca americana). Perfluorohexanesulfonic acid (PFHxS) averaged thousands of ng/g ww in the livers of birds and house mice, but one order of magnitude lower in the livers of upland desert rodent species. PFAS levels were strikingly lower at control sites, even for highly mobile migratory species. Tissue concentrations were correlated within individuals, and consistently higher in liver than in muscle or blood. Twenty of 23 vertebrate species sampled at Holloman AFB were heavily contaminated, representing multiple trophic levels and microhabitats, and implicating a range of pathways for PFAS spread: ingestion of surface water, sediments, and dust; foraging on aquatic invertebrates and plants by secondary consumers; and preying upon small vertebrates by higher level consumers, including consumption of game species by hunters. Unlike in other aquatic systems, piscivory was not an important pathway of PFAS uptake. In sum, legacy PFAS at a desert wetland have permeated the local food web across a period of decades, severely contaminating resident and migrant animals, and likely exposing humans via game meat consumption and outdoor recreation.

Five highlights

A biodiverse, wetland food web at a military base is heavily contaminated with PFAS.

Littoral-zone mice and aquatic birds had high liver PFOS, up to 97,000 ng/g ww.

Species and ecological variation were high among 16 PFAS detected in animal tissues.

Game species had dangerously contaminated meat and can transport it long distances.

Biorepositories provide key temporal and spatial sampling for contaminant studies.

Graphical abstract
Robust estimation of cancer and immune cell-type proportions from bulk tumor ATAC-Seq data
Authors: Gabriel Aurélie AG , Racle Julien , Falquet Maryline , Jandus Camilla , Gfeller David
Published: October 2023

Assay for Transposase-Accessible Chromatin sequencing (ATAC-Seq) is a widely used technique to explore gene regulatory mechanisms. For most ATAC-Seq data from healthy and diseased tissues such as tumors, chromatin accessibility measurement represents a mixed signal from multiple cell types. In this work, we derive reliable chromatin accessibility marker peaks and reference profiles for most non-malignant cell types frequently observed in the micro-environment of human tumors. We then integrate these data into the EPIC deconvolution framework (Racleet al., 2017) to quantify cell-type heterogeneity in bulk ATAC-Seq data. Our EPIC-ATAC tool accurately predicts non-malignant and malignant cell fractions in tumor samples. When applied to a human breast cancer cohort, EPIC-ATAC accurately infers the immune contexture of the main breast cancer subtypes.
Early Neolithic forest farming at Seven Springs, Martlesham, Suffolk inferred from sedaDNA and pollen
Authors: Hudson Samuel M. , Allen Steven J. , Alsos Inger Greve , Curl Julie , Heintzman Peter D. , Hughes Paul , Gardiner Lynne , Lloyd-Smith Lindsay , Pears Ben , Scaife Rob , Stoof-Leichsenring Kathleen R. , Brown Antony
Published: October 2023

The importance of small wetlands and springs to Mesolithic cultures is well established. However, few studies have focused on their significance and use by Early Neolithic agro-pastoralists. Here we present a multiproxy palaeoenvironmental analysis, including ‘authenticated’ sedimentary ancient DNA (sedaDNA), at Seven Springs, Martlesham, UK, indicating that the springs provided an attractive location for pastoral and ritual activity around a palaeochannel surrounded by dense woodland. We demonstrate that sedaDNA can be preserved well within stratigraphically complex wetland sediment sequences, allowing archaeologically valuable insights into crucial periods of change in the prehistoric, where other forms of environmental evidence can be scarce.
Xbra modulates the activity of linker region phosporlated Smad1 duringXenopussomitogenesis
Authors: Kumar Santosh , Umair Zobia , Goutam Ravi Shankar , Lee Unjoo , Kim Jaebong
Published: October 2023

The Bmp/Smad1 pathway plays a crucial role in developmental processes and tissue homeostasis. Mitogen-activated protein kinase (Mapk)/Erk mediated phosphorylation of Smad1 in the linker region leads to Smad1 degradation, cytoplasmic retention and inhibition of Bmp/Smad1 signaling. While Fgf/Erk pathway has been documented to inhibit Bmp/Smad1 signaling, several studies also suggests the cooperative interaction between these two pathways in different context. However, the precise role and molecular pathway of this collaborative interaction remain obscure. Here, we identified Xbra induced by Fgf/Erk signaling as a factor in a protective mechanism for Smad1. Xbra physically interacted with the linker region phosphorylated Smad1 to make Xbra/Smad1/Smad4 trimeric complex, leading to Smad1 nuclear localization and protecting it from ubiquitin-mediated proteasomal degradation. This interaction of Xbra/Smad1/Smad4 led to sustained nuclear localization of Smad1 and the upregulation of lateral mesoderm genes, while concurrently suppression of neural and blood forming genes. Taken together, the results suggests Xbra-dependent cooperative interplays between Fgf/Erk and Bmp/Smad1 signaling during lateral mesoderm specification inXenopusembryos.