The protein-only RNase Ps, endonucleases that cleave pre-tRNA: Biological relevance, molecular architectures, substrate recognition and specificity, and protein interactomes.

Protein-only RNase P (PRORP) is an essential enzyme responsible for the 5' maturation of precursor tRNAs (pre-tRNAs). PRORPs are classified into three categories with unique molecular architectures, although all three classes of PRORPs share a mechanism and have similar active sites. Single subunit PRORPs, like those found in plants, have multiple isoforms with different localizations, substrate specificities, and temperature sensitivities. Most recently, Arabidopsis thaliana PRORP2 was shown to interact with TRM1A and B, highlighting a new potential role between these enzymes. Work with At PRORPs led to the development of a ribonuclease that is being used to protect against plant viruses. The mitochondrial RNase P complex, found in metazoans, consists of PRORP, TRMT10C, and SDR5C1, and has also been shown to have substrate specificity, although the cause is unknown. Mutations in mitochondrial tRNA and mitochondrial RNase P have been linked to human disease, highlighting the need to continue understanding this complex. The last class of PRORPs, homologs of Aquifex RNase P (HARPs), is found in thermophilic archaea and bacteria. This most recently discovered type of PRORP forms a large homo-oligomer complex. Although numerous structures of HARPs have been published, it is still unclear how HARPs bind pre-tRNAs and in what ratio. There is also little investigation into the substrate specificity and ideal conditions for HARPs. Moving forward, further work is required to fully characterize each of the three classes of PRORP, the pre-tRNA binding recognition mechanism, the rules of substrate specificity, and how these three distinct classes of PRORP evolved. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.

Multiple structural flavors of RNase P in precursor tRNA processing.

The precursor transfer RNAs (pre-tRNAs) require extensive processing to generate mature tRNAs possessing proper fold, structural stability, and functionality required to sustain cellular viability. The road to tRNA maturation follows an ordered process: 5'-processing, 3'-processing, modifications at specific sites, if any, and 3'-CCA addition before aminoacylation and recruitment to the cellular protein synthesis machinery. Ribonuclease P (RNase P) is a universally conserved endonuclease in all domains of life, performing the hydrolysis of pre-tRNA sequences at the 5' end by the removal of phosphodiester linkages between nucleotides at position -1 and +1. Except for an archaeal species: Nanoarchaeum equitans where tRNAs are transcribed from leaderless-position +1, RNase P is indispensable for life and displays fundamental variations in terms of enzyme subunit composition, mechanism of substrate recognition and active site architecture, utilizing in all cases a two metal ion-mediated conserved catalytic reaction. While the canonical RNA-based ribonucleoprotein RNase P has been well-known to occur in bacteria, archaea, and eukaryotes, the occurrence of RNA-free protein-only RNase P in eukaryotes and RNA-free homologs of Aquifex RNase P in prokaryotes has been discovered more recently. This review aims to provide a comprehensive overview of structural diversity displayed by various RNA-based and RNA-free RNase P holoenzymes towards harnessing critical RNA-protein and protein-protein interactions in achieving conserved pre-tRNA processing functionality. Furthermore, alternate roles and functional interchangeability of RNase P are discussed in the context of its employability in several clinical and biotechnological applications. This article is categorized under: RNA Processing > tRNA Processing RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.

The significance of shooting angle in seal shooting.

The present study aimed to investigate the relationship between shooting angle to the head and animal welfare outcomes in the hunt of young harp seals (Pagophilus groenlandicus). The study population consisted of young harp seals belonging to the Greenland Sea harp seal population. A sample of 171, 2-7 weeks old, weaned harp seals of both sexes were included. The study was conducted as an open, randomised parallel group designed trial during the regular hunt. The animals were allocated into four groups, A-D, according to the observed shooting angle to the head, defined as the angle between the direction of the shot and the longitudinal axis of the animal's head: (A) directly from the front; (B) obliquely from the front; (C) directly from the side; and (D) obliquely or directly from behind. Instantaneous death rate (IDR) and time to death (TTD) were the main variables. The mean IDR differed significantly between groups and was highest in group B (96.8%) and lowest in group C (66.7%). For all groups combined it was 84.2%. The mean TTD for seals not rendered instantaneously unconscious or dead (n = 27) differed significantly between groups and was shortest in group A (16 s) and longest in group C (85 s). However, the number of animals included in the TTD analysis was limited. In conclusion, based on the significantly higher IDR, the shooting angle obliquely from the front is recommended to help achieve the best animal welfare outcomes during the hunt of young harp seals.

Microarchitecture of the penis bone (baculum) of a seal: A 3D morphometric examination using synchrotron and laboratory micro-computed tomography.

We examined the ultrastructure of the mammalian os penis at the high-resolution synchrotron level. Previously, bacular microanatomy had only been investigated histologically. We studied the baculum of the harp seal (Pagophilus groenlandicus), in which the baculum varies more in size and shape than does a mechanically constrained bone (humerus). We (1) investigated the microarchitecture of bacula and humeri from the same seal specimens, and (2) described changes in bone micro- and macro-morphology associated with age (n = 15, age range = 1-35 years) and bone type. We analyzed cross-sectional geometry non-destructively through laboratory micro-computed tomography. We suggest that the midshaft may resist axial compression while the proximal region may resist torsion, based on measurements of cross-sectional and cortical areas, perimeter, ratio of maximum and minimum moments of inertia, and polar moment of inertia. In addition, midshaft bacula may be less mechanosensitive than humeri, based on microstructural variables (e.g., volume, surface area, diameter associated with lacunae and cortical porosity) analyzed across age groupings. Our findings related to the microarchitecture of the pinniped baculum provide a basis for further studies on development, mechanical properties, functions, and adaptations in this and other pinniped species. Our use of a multi-modal imaging approach was minimally destructive for reproducible and accurate comparison of three-dimensional bone ultrastructure. Such methods, coupled with multidisciplinary analyses, enable diverse studies of bone biology, life history, and evolution using museum collections.

Discovery, structure, mechanisms, and evolution of protein-only RNase P enzymes.

The endoribonuclease RNase P is responsible for tRNA 5' maturation in all domains of life. A unique feature of RNase P is the variety of enzyme architectures, ranging from dual- to multi-subunit ribonucleoprotein forms with catalytic RNA subunits to protein-only enzymes, the latter occurring as single- or multi-subunit forms or homo-oligomeric assemblies. The protein-only enzymes evolved twice: a eukaryal protein-only RNase P termed PRORP and a bacterial/archaeal variant termed homolog of Aquifex RNase P (HARP); the latter replaced the RNA-based enzyme in a small group of thermophilic bacteria but otherwise coexists with the ribonucleoprotein enzyme in a few other bacteria as well as in those archaea that also encode a HARP. Here we summarize the history of the discovery of protein-only RNase P enzymes and review the state of knowledge on structure and function of bacterial HARPs and eukaryal PRORPs, including human mitochondrial RNase P as a paradigm of multi-subunit PRORPs. We also describe the phylogenetic distribution and evolution of PRORPs, as well as possible reasons for the spread of PRORPs in the eukaryal tree and for the recruitment of two additional protein subunits to metazoan mitochondrial PRORP. We outline potential applications of PRORPs in plant biotechnology and address diseases associated with mutations in human mitochondrial RNase P genes. Finally, we consider possible causes underlying the displacement of the ancient RNA enzyme by a protein-only enzyme in a small group of bacteria.

Vocal Fatigue Experiences and Mitigation Strategies in the Sacred Harp Singing Community.

OBJECTIVES: Sacred Harp singers sing at a high volume for sustained periods of time without collective warm-up or cool-down exercises, ostensibly putting them at elevated risk for vocal fatigue (VF) and associated vocal pathologies. Participants are also likely to lack formal vocal training. The purpose of this study was to (1) assess singers' experiences with VF, (2) document singers' strategies for mitigating VF, and (3) determine whether vocal training was associated with decreased vocal difficulties. STUDY DESIGN: Self-reporting via online questionnaire containing quantitative and qualitative items. METHODS: This study employed an online questionnaire that combined demographic items, open-ended questions, and the Evaluation of the Ability to Sing Easily (EASE). Participants were recruited at one in-person event and via social media and a mailing list. RESULTS: This study returned 134 valid responses. Singers with formal choral experience scored lower on the EASE and two subscales, but length of experience had no impact. There were no correlations between vocal training and EASE scores. Women scored higher on the EASE than men and nonbinary individuals, while age, length of experience with Sacred Harp singing, and frequency of attendance at annual singing events were all negatively correlated with EASE score. Singers reported a wide range of mitigation strategies, most of which are unique to the Sacred Harp context. CONCLUSIONS: Sacred Harp singers do not appear to struggle more with VF than other populations of singers. However, a few characteristics of their practice put them at risk, and many singers would benefit from professional guidance concerning vocal health.

Forearm muscles activity of harp players.

The practice of a musical instrument requires fine dexterity, repetitive, fast, and precise movements, as well as important efforts to set the instrument into vibration, while adopting postures often unnatural for the human body. As a result, musicians are often subject to pain and musculoskeletal disorders. In the case of plucked string instruments and especially the concert harp, the plucking force is directly related to the strings' tension. Consequently, the choice of the strings has to be made based on both, the musician feel while playing, and the musculoskeletal consequences. This paper investigates how the string properties and the playing dynamics affect the finger and wrist muscle activity during harp playing. This study first emphasized the noteworthy recruitment of the flexor and extensor muscles (42% and 29% of MVC, respectively). Findings outlined further that the fingering choice, the adopted playing dynamics and the string's material govern the muscular activity level and the playing control. Such results are a first step to better understand how the harp ergonomics may affect the player's integrity and help them decide the most suitable stringing for their practice.

Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings.

Natural gut harp strings are made from twisted bundles of gut strips, which are dried, ground, and varnished. The effects of varying the twist angle and surface finishing on the mechanical properties of gut harp strings have been explored. Strings were tested over a range of twist angles from 23.5∘ to 58.3∘, and with all four combinations of ground or unground and varnished or unvarnished surface finishing. The principal effects of varying the degree of twisting were that the breaking strength and tensile Young's modulus both fell as the twist angle was increased. String makers must therefore make a compromise between sound quality and string strength and durability. Leaving the string unvarnished dramatically increased the sensitivity to changes in humidity, which, in turn, affected the thermal tuning sensitivity and creep behaviour. Grinding the string surface prior to varnishing had no significant effect on the behaviour, but did make some difference to the thermal tuning sensitivity if the string was left unvarnished. Increasing the humidity frequently triggered episodes of additional string creep. There appeared to be a threshold effect, with the additional creep triggered when the string linear density exceeded its previous maximum. When the string was not creeping, there appeared to be a strong coupling mechanism between changes in the linear density and complementary changes in the string tension, such that there was almost no net effect on the string frequency. This behaviour was independent of the twist angle and the surface finishing, suggesting that whatever the coupling mechanism was, it was not dependent on the twisted structure of the string.

Clinical value of Hospital Admission Risk Profile (HARP) and the Identification of Seniors at Risk (ISAR) scales to predict hospital-associated functional decline in an acute geriatric unit in Colombia.

Background: Older adults admitted to a hospital for acute illness are at higher risk of hospital-associated functional decline during stays and after discharge. Objective: This study aimed to assess the calibration and discriminative abilities of the Hospital Admission Risk Profile (HARP) and the Identification of Seniors at Risk (ISAR) scales as predictors of hospital-associated functional decline at discharge in a cohort of patients older than age 65 receiving management in an acute geriatric care unit in Colombia. Methods: This study is an external validation of ISAR and HARP prediction models in a cohort of patients over 65 years managed in an acute geriatric care unit. The study included patients with Barthel index measured at admission and discharge. The evaluation discriminate ability and calibration, two fundamental aspects of the scales. Results: Of 833 patients evaluated, 363 (43.6%) presented hospital-associated functional decline at discharge. The HARP underestimated the risk of hospital-associated functional decline for patients in low- and intermediate-risk categories (relation between observed/expected events (ROE) 1.82 and 1.51, respectively). The HARP overestimated the risk of hospital-associated functional decline for patients in the high-risk category (ROE 0.91). The ISAR underestimated the risk of hospital-associated functional decline for patients in low- and high-risk categories (ROE 1.59 and 1.11). Both scales showed poor discriminative ability, with an area under the curve (AUC) between 0.55 and 0.60. Conclusions: This study found that HARP and ISAR scales have limited discriminative ability to predict HAFD at discharge. The HARP and ISAR scales should be used cautiously in the Colombian population since they underestimate the risk of hospital-associated functional decline and have low discriminative ability.

Antecedentes: los adultos mayores ingresados en un hospital por una enfermedad aguda tienen un mayor riesgo de deterioro functional hospitalario durante su estancia y después del alta. Objetivo: este estudio tuvo como objetivo evaluar las capacidades de calibración y discriminación de las escalas Hospital Admission Risk Profile (HARP) e Identification of Seniors at Risk (ISAR) como predictores de deterioro funcional hospitalario al alta en una cohorte de pacientes mayores de 65 años que recibieron manejo en una unidad geriátrica de agudos en Colombia. Métodos: este estudio es una validación externa de los modelos de predicción ISAR y HARP en una cohorte de pacientes mayores de 65 años atendidos en una unidad geriátrica de agudos. El estudio incluyó pacientes con índice de Barthel medido al ingreso y al alta y la evaluación de la capacidad de discriminación y calibración, dos aspectos fundamentales para esta medición. Resultados: de 833 pacientes evaluados, 363 (43.6%) presentaron deterioro funcional hospitalario al momento del alta. La escala HARP subestimó el riesgo de deterioro funcional hospitalario para los pacientes en las categorías de riesgo bajo e intermedio (relación entre eventos observados /esperados (ROE) 1.82 y 1.51, respectivamente). El HARP sobrestimó el riesgo de deterioro funcional hospitalario para pacientes en la categoría de alto riesgo (ROE 0.91). El ISAR subestimó el riesgo de deterioro hospitalario para pacientes en categorías de bajo y alto riesgo (ROE 1.59 y 1.11). Ambas escalas mostraron una pobre capacidad de discriminación, con un área bajo la curva (AUC) entre 0.55 y 0.60. Conclusiones: este estudio encontró que las escalas HARP e ISAR tienen una capacidad de discriminación limitada para predecir deterioro funcional hospitalario al alta. Las escalas HARP e ISAR deben usarse con cautela en la población colombiana ya que subestiman el riesgo de deterioro funcional hospitalario y tienen baja capacidad de discriminación.

Multi-decadal trends in biomarkers in harp seal teeth from the North Atlantic reveal the influence of prey availability on seal trophic position.

Arctic food webs are being impacted by borealisation and environmental change. To quantify the impact of these multiple forcings, it is crucial to accurately determine the temporal change in key ecosystem metrics, such as trophic position of top predators. Here, we measured stable nitrogen isotopes (δ15 N) in amino acids in harp seal teeth from across the North Atlantic spanning a period of 60 years to robustly assess multi-decadal trends in harp seal trophic position, accounting for changes in δ15 N at the base of the food web. We reveal long-term variations in trophic position of harp seals which are likely to reflect fluctuations in prey availability, specifically fish- or invertebrate-dominated diets. We show that the temporal trends in harp seal trophic position differ between the Northwest Atlantic, Greenland Sea and Barents Sea, suggesting divergent changes in each local ecosystem. Our results provide invaluable data for population dynamic and ecotoxicology studies.

Clinical value of Hospital Admission Risk Profile (HARP) and the Identification of Seniors at Risk (ISAR) scales to predict hospital-associated functional decline in an acute geriatric unit in Colombia

Background: Older adults admitted to a hospital for acute illness are at higher risk of hospital-associated functional decline during stays and after discharge. Objective: This study aimed to assess the calibration and discriminative abilities of the Hospital Admission Risk Profile (HARP) and the Identification of Seniors at Risk (ISAR) scales as predictors of hospital-associated functional decline at discharge in a cohort of patients older than age 65 receiving management in an acute geriatric care unit in Colombia. Methods: This study is an external validation of ISAR and HARP prediction models in a cohort of patients over 65 years managed in an acute geriatric care unit. The study included patients with Barthel index measured at admission and discharge. The evaluation discriminate ability and calibration, two fundamental aspects of the scales. Results: Of 833 patients evaluated, 363 (43.6%) presented hospital-associated functional decline at discharge. The HARP underestimated the risk of hospital-associated functional decline for patients in low- and intermediate-risk categories (relation between observed/expected events (ROE) 1.82 and 1.51, respectively). The HARP overestimated the risk of hospital-associated functional decline for patients in the high-risk category (ROE 0.91). The ISAR underestimated the risk of hospital-associated functional decline for patients in low- and high-risk categories (ROE 1.59 and 1.11). Both scales showed poor discriminative ability, with an area under the curve (AUC) between 0.55 and 0.60. Conclusions: This study found that HARP and ISAR scales have limited discriminative ability to predict HAFD at discharge. The HARP and ISAR scales should be used cautiously in the Colombian population since they underestimate the risk of hospital-associated functional decline and have low discriminative ability.

Antecedentes: los adultos mayores ingresados en un hospital por una enfermedad aguda tienen un mayor riesgo de deterioro functional hospitalario durante su estancia y después del alta. Objetivo: este estudio tuvo como objetivo evaluar las capacidades de calibración y discriminación de las escalas Hospital Admission Risk Profile (HARP) e Identification of Seniors at Risk (ISAR) como predictores de deterioro funcional hospitalario al alta en una cohorte de pacientes mayores de 65 años que recibieron manejo en una unidad geriátrica de agudos en Colombia. Métodos: este estudio es una validación externa de los modelos de predicción ISAR y HARP en una cohorte de pacientes mayores de 65 años atendidos en una unidad geriátrica de agudos. El estudio incluyó pacientes con índice de Barthel medido al ingreso y al alta y la evaluación de la capacidad de discriminación y calibración, dos aspectos fundamentales para esta medición. Resultados: de 833 pacientes evaluados, 363 (43.6%) presentaron deterioro funcional hospitalario al momento del alta. La escala HARP subestimó el riesgo de deterioro funcional hospitalario para los pacientes en las categorías de riesgo bajo e intermedio (relación entre eventos observados /esperados (ROE) 1.82 y 1.51, respectivamente). El HARP sobrestimó el riesgo de deterioro funcional hospitalario para pacientes en la categoría de alto riesgo (ROE 0.91). El ISAR subestimó el riesgo de deterioro hospitalario para pacientes en categorías de bajo y alto riesgo (ROE 1.59 y 1.11). Ambas escalas mostraron una pobre capacidad de discriminación, con un área bajo la curva (AUC) entre 0.55 y 0.60. Conclusiones: este estudio encontró que las escalas HARP e ISAR tienen una capacidad de discriminación limitada para predecir deterioro funcional hospitalario al alta. Las escalas HARP e ISAR deben usarse con cautela en la población colombiana ya que subestiman el riesgo de deterioro funcional hospitalario y tienen baja capacidad de discriminación.

Dynamics of dissolved organic carbon during drought and flood events: A phase-by-stages perspective.

Dissolved organic carbon (DOC) is a key water quality parameter that plays a crucial role in controlling aquatic ecosystems and carbon cycling. Understanding DOC dynamics during hydrological extremes (i.e., droughts and floods) helps in managing water quality, but such variability is rarely studied. Furthermore, how differences in DOC concentrations among phase-by-stages of drought/flood affect simulation performances based on hydrological features remains unclear. Here, phase-by-stages of hydrological drought (flood) were divided into intensification (rising) and recovery (falling) periods based on drought peak intensity (flood peak intensity). The long-term (1976-2019) daily discharge and weekly (biweekly) DOC concentrations from four headwater streams with different watershed sizes (from 9.97 to 119.09 ha) in south-central Ontario, Canada, were used to achieve the above aims. The results showed that (i) the average DOC concentration during intensification (rising) stage of drought (flood) was smaller (larger) than during recovery (falling). (ii) Simulations performed better when accounting for phase-by-stages of drought/flood, with reductions in mean absolute percentage error of 32.85 % and 53.59 % for drought and flood events, respectively. These results will help understand the dynamics of DOC during hydrological extremes and improve simulation performance of numerical models for water quality parameters under changing environmental conditions.

Characterization of RNA-based and protein-only RNases P from bacteria encoding both enzyme types.

A small group of bacteria encode two types of RNase P, the classical ribonucleoprotein (RNP) RNase P as well as the protein-only RNase P HARP (homolog of Aquifex RNase P). We characterized the dual RNase P activities of five bacteria that belong to three different phyla. All five bacterial species encode functional RNA (gene rnpB) and protein (gene rnpA) subunits of RNP RNase P, but only the HARP of the thermophile Thermodesulfatator indicus (phylum Thermodesulfobacteria) was found to have robust tRNA 5'-end maturation activity in vitro and in vivo in an Escherichia coli RNase P depletion strain. These findings suggest that both types of RNase P are able to contribute to the essential tRNA 5'-end maturation activity in T. indicus, thus resembling the predicted evolutionary transition state in the progenitor of the Aquificaceae before the loss of rnpA and rnpB genes in this family of bacteria. Remarkably, T. indicus RNase P RNA is transcribed with a P12 expansion segment that is posttranscriptionally excised in vivo, such that the major fraction of the RNA is fragmented and thereby truncated by ∼70 nt in the native T. indicus host as well as in the E. coli complementation strain. Replacing the native P12 element of T. indicus RNase P RNA with the short P12 helix of Thermotoga maritima RNase P RNA abolished fragmentation, but simultaneously impaired complementation efficiency in E. coli cells, suggesting that intracellular fragmentation and truncation of T. indicus RNase P RNA may be beneficial to RNA folding and/or enzymatic activity.

The Biochemical Mechanism of Fork Regression in Prokaryotes and Eukaryotes-A Single Molecule Comparison.

The rescue of stalled DNA replication forks is essential for cell viability. Impeded but still intact forks can be rescued by atypical DNA helicases in a reaction known as fork regression. This reaction has been studied at the single-molecule level using the Escherichia coli DNA helicase RecG and, separately, using the eukaryotic SMARCAL1 enzyme. Both nanomachines possess the necessary activities to regress forks: they simultaneously couple DNA unwinding to duplex rewinding and the displacement of bound proteins. Furthermore, they can regress a fork into a Holliday junction structure, the central intermediate of many fork regression models. However, there are key differences between these two enzymes. RecG is monomeric and unidirectional, catalyzing an efficient and processive fork regression reaction and, in the process, generating a significant amount of force that is used to displace the tightly-bound E. coli SSB protein. In contrast, the inefficient SMARCAL1 is not unidirectional, displays limited processivity, and likely uses fork rewinding to facilitate RPA displacement. Like many other eukaryotic enzymes, SMARCAL1 may require additional factors and/or post-translational modifications to enhance its catalytic activity, whereas RecG can drive fork regression on its own.

Stradivari harp tree-ring data.

Three tree ring sequences were collected on the soundboard of the Stradivari harp. Due to the presence of the strings in the centre of the harp soundboard, the sampling of the tree ring widths was focused separately on the right side (RX), the central (CX) and the left side (LX). Tree ring measurements were carried out by using the Video Time Table (VTT), an instrument that combines a portable measuring device and a digital, high-resolution video camera. The VTT allowed non-invasive measurements of the tree rings to be made in situ and to immediately verify the quality of the sampling. The growth rings of the central portion were sampled using a high-resolution camera, which made it possible to bypass the barrier formed by the neck and strings. The consequent parallax and focus problems were overcome by taking many photographs from different angles. The measurements on the photographs were made with the CooRecorder program. The dendrochronological data were acquired with the PAST4 program and graphically processed and analysed with the PAST4 and 5 programs.

Structural and mechanistic basis of RNA processing by protein-only ribonuclease P enzymes.

Ribonuclease P (RNase P) enzymes are responsible for the 5' processing of tRNA precursors. In addition to the well-characterised ribozyme-based RNase P enzymes, an evolutionarily distinct group of protein-only RNase Ps exists. These proteinaceous RNase Ps (PRORPs) can be found in all three domains of life and can be divided into two structurally different types: eukaryotic and prokaryotic. Recent structural studies on members of both families reveal a surprising diversity of molecular architectures, but also highlight conceptual and mechanistic similarities. Here, we provide a comparison between the different types of PRORP enzymes and review how the combination of structural, biochemical, and biophysical studies has led to a molecular picture of protein-mediated tRNA processing.

Evaluation of the Preservation and Digestion of Seal Meat Processed with Heating and Antioxidant Seal Meat Hydrolysates.

Seal meat is of high nutritive value but is not highly exploited for human food due to ethical issues, undesirable flavors, and loss of nutrients during the processing/cooking step. In this work, commercially available processed seal meat was treated with its hydrolysates as preservatives with the aim of improving nutrient bioavailability. The contents of the nutrients were analyzed after digestion using a simulated dynamic digestion model, and the effects of different processing conditions, i.e., low-temperature processing and storage (25 °C) and high-temperature cooking (100 °C), of seal meat were investigated. Hydrolysates with antioxidant activity decreased the amounts of the less desirable Fe3+ ions in the seal meat digests. After treatment with hydrolysates at room temperature, a much higher total Fe content of 781.99 mg/kg was observed compared to other treatment conditions. The release of amino acids increased with temperature and was 520.54 mg/g for the hydrolysate-treated sample versus 413.12 mg/g for the control seal meat sample treated in buffer. Overall, this study provides useful data on the potential use of seal meat as a food product with high nutritive value and seal meat hydrolysates with antioxidant activity as preservatives to control oxidation in food.

Multi-decadal environmental change in the Barents Sea recorded by seal teeth.

Multiple environmental forcings, such as warming and changes in ocean circulation and nutrient supply, are affecting the base of Arctic marine ecosystems, with cascading effects on the entire food web through bottom-up control. Stable nitrogen isotopes (δ15 N) can be used to detect and unravel the impact of these forcings on this unique ecosystem, if the many processes that affect the δ15 N values are constrained. Combining unique 60-year records from compound specific δ15 N biomarkers on harp seal teeth alongside state-of-the-art ocean modelling, we observed a significant decline in the δ15 N values at the base of the Barents Sea food web from 1951 to 2012. This strong and persistent decadal trend emerges due to the combination of anthropogenic atmospheric nitrogen deposition in the Atlantic, increased northward transport of Atlantic water through Arctic gateways and local feedbacks from increasing Arctic primary production. Our results suggest that the Arctic ecosystem has been responding to anthropogenically induced local and remote drivers, linked to changing ocean biology, chemistry and physics, for at least 60 years. Accounting for these trends in δ15 N values at the base of the food web is essential to accurately detect ecosystem restructuring in this rapidly changing environment.

Fog collection behavior of bionic surface and large fog collector: A review.

Water shortages are currently becoming more and more serious due to complicated factors such as the development of the economy, environmental pollution, and climate deterioration. And it is the best solution to the problems faced by people in today's world to investigate the bionic structure of nature and explore effective methods for fog collection. Herein, we've illustrated the bionic structures of the Namib desert beetle, cactus spines, and spider silk, and we imitate and further modify the respective bionic structures, as well as construct multifunctional bionic structures to improve fog collection. In addition, we also expound the fog collection behavior of a large fog collector, and an excellent fog capture effect was achieved through studying the mesh structure, the surface modification of the mesh, and the construction of the fog collector. The advantages and limitations of fog collection by a harp fog collector were also explored. We hope that through this review, relevant researchers can have a deeper understanding of this field and thus promote the development of fog collection.

Optimizing Fog Harps.

It has recently been demonstrated that harps harvest substantively more fog water than conventional mesh nets, but the optimal design for fog harps remains unknown. Here, we systematically vary key parameters of a scale-model fog harp, the wire material, wire pitch, and wire length, to find the optimal combination. We found stainless steel to not only be the best hydrophilic wire material but also nearly be as effective as Teflon-coated wires. The best choice for the wire pitch was coupled to the wire length, as the smallest pitch collected the most water for short harps but was hampered by tangling for taller harps. Accordingly, we use an elastocapillary wire tangling model to successfully predict the onset of tangling beyond a critical length for any given wire pitch. Combining what we learned, we achieved a water harvesting efficiency of 17% with an optimized stainless-steel harp, over three times higher than that of the current standard of a Raschel mesh. These results suggest that an optimal fog harp should feature high-tension, uncoated wires within a large aspect ratio frame to avoid tangling and promote efficient and reliable fog harvesting.