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Glioblastoma (GBM) cells are highly invasive, infiltrating the surrounding normal brain tissue, thereby limiting the efficacy of surgical resection and focal radiotherapy. Cysteamine, a small aminothiol molecule that is orally bioavailable and approved for cystinosis, has potential as a cancer treatment by inhibiting tumor cell invasion and metastasis. Here we demonstrate that these potential therapeutic effects of cysteamine are likely due to the inhibition of matrix metalloproteinases (MMPs) in GBM. In vitro assays confirmed that micromolar concentrations of cysteamine were not cytotoxic, enabling the interrogation of the cellular effects without confounding tumor cell loss. Cysteamine's inhibition of MMP activity, especially the targeting of MMP2, MMP9, and MMP14, was observed at micromolar concentrations, suggesting the mechanism of action in suppressing invasion and cell migration is by inhibition of these MMPs. These findings suggest that achievable micromolar concentrations of cysteamine effectively inhibit cancer cell invasion and migration in GBM, supporting the potential for use as an adjunct cancer treatment.
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The early-life gut microbiome development has long-term health impacts and can be influenced by factors such as infant diet. Human milk oligosaccharides (HMOs), an essential component of breast milk that can only be metabolized by some beneficial gut microorganisms, ensure proper gut microbiome establishment and infant development. However, how HMOs are metabolized by gut microbiomes is not fully elucidated. Isolate studies have revealed the genetic basis for HMO metabolism, but they exclude the possibility of HMO assimilation via synergistic interactions involving multiple organisms. Here, we investigate microbiome responses to 2'-fucosyllactose (2'FL), a prevalent HMO and a common infant formula additive, by establishing individualized microbiomes using fecal samples from three infants as the inocula. Bifidobacterium breve, a prominent member of infant microbiomes, typically cannot metabolize 2'FL. Using metagenomic data, we predict that extracellular fucosidases encoded by co-existing members such as Ruminococcus gnavus initiate 2'FL breakdown, thus critical for B. breve's growth. Using both targeted co-cultures and by supplementation of R. gnavus into one microbiome, we show that R. gnavus can promote extensive growth of B. breve through the release of lactose from 2'FL. Overall, microbiome cultivation combined with genome-resolved metagenomics demonstrates that HMO utilization can vary with an individual's microbiome.
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Bifidobacterium , Microbiota , Femenino , Niño , Humanos , Lactante , Bifidobacterium/genética , Bifidobacterium/metabolismo , Trisacáridos/metabolismo , Leche Humana/química , Oligosacáridos/metabolismoRESUMEN
TruAB Discovery is an approach that integrates cellular immunology, high-throughput immunosequencing, bioinformatics, and computational biology in order to discover naturally occurring human antibodies for prophylactic or therapeutic use. We adapted our previously described pairSEQ technology to pair B cell receptor heavy and light chains of SARS-CoV-2 spike protein-binding antibodies derived from enriched antigen-specific memory B cells and bulk antibody-secreting cells. We identified approximately 60,000 productive, in-frame, paired antibody sequences, from which 2,093 antibodies were selected for functional evaluation based on abundance, isotype and patterns of somatic hypermutation. The exceptionally diverse antibodies included RBD-binders with broad neutralizing activity against SARS-CoV-2 variants, and S2-binders with broad specificity against betacoronaviruses and the ability to block membrane fusion. A subset of these RBD- and S2-binding antibodies demonstrated robust protection against challenge in hamster and mouse models. This high-throughput approach can accelerate discovery of diverse, multifunctional antibodies against any target of interest.
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COVID-19 , SARS-CoV-2 , Animales , Ratones , Humanos , Anticuerpos Neutralizantes , Anticuerpos ampliamente neutralizantes , Anticuerpos AntiviralesRESUMEN
BACKGROUND: Transfusion-associated circulatory overload (TACO) is a severe adverse reaction (AR) contributing to the leading cause of mortality associated with transfusions. As strategies to mitigate TACO have been increasingly adopted, an update of prevalence rates and risk factors associated with TACO using the growing sources of electronic health record (EHR) data can help understand transfusion safety. STUDY DESIGN AND METHODS: This retrospective study aimed to provide a timely and reproducible assessment of prevalence rates and risk factors associated with TACO. Novel natural language processing methods, now made publicly available on GitHub, were developed to extract ARs from 3178 transfusion reaction reports. Other patient-level data were extracted computationally from UCSF EHR between 2012 and 2022. The odds ratio estimates of risk factors were calculated using a multivariate logistic regression analysis with case-to-control matched on sex and age at a ratio of 1:5. RESULTS: A total of 56,208 patients received transfusions (total 573,533 units) at UCSF during the study period and 102 patients developed TACO. The prevalence of TACO was estimated to be 0.2% per patient (102/total 56,208). Patients with a history of coagulopathy (OR, 1.36; 95% CI, 1.04-1.79) and transplant (OR, 1.99; 95% CI, 1.48-2.68) were associated with increased odds of TACO. DISCUSSION: While TACO is a serious AR, events remained rare, even in populations enriched with high-risk patients. Novel computational methods can be used to find and continually surveil for transfusion ARs. Results suggest that patients with history or presence of coagulopathy and organ transplant should be carefully monitored to mitigate potential risks of TACO.
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Registros Electrónicos de Salud , Reacción a la Transfusión , Humanos , Estudios Retrospectivos , Reacción a la Transfusión/epidemiología , Transfusión Sanguínea/métodos , Factores de RiesgoRESUMEN
Sweat bees have repeatedly gained and lost eusociality, a transition from individual to group reproduction. Here we generate chromosome-length genome assemblies for 17 species and identify genomic signatures of evolutionary trade-offs associated with transitions between social and solitary living. Both young genes and regulatory regions show enrichment for these molecular patterns. We also identify loci that show evidence of complementary signals of positive and relaxed selection linked specifically to the convergent gains and losses of eusociality in sweat bees. This includes two pleiotropic proteins that bind and transport juvenile hormone (JH)-a key regulator of insect development and reproduction. We find that one of these proteins is primarily expressed in subperineurial glial cells that form the insect blood-brain barrier and that brain levels of JH vary by sociality. Our findings are consistent with a role of JH in modulating social behaviour and suggest that eusocial evolution was facilitated by alteration of the proteins that bind and transport JH, revealing how an ancestral developmental hormone may have been co-opted during one of life's major transitions. More broadly, our results highlight how evolutionary trade-offs have structured the molecular basis of eusociality in these bees and demonstrate how both directional selection and release from constraint can shape trait evolution.
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Conducta Social , Sudor , Abejas , Animales , Reproducción , FenotipoRESUMEN
BACKGROUND: Randomized trials are the gold-standard for clinical evidence generation, but they can sometimes be limited by infeasibility and unclear generalizability to real-world practice. External control arm (ECA) studies may help address this evidence gaps by constructing retrospective cohorts that closely emulate prospective ones. Experience in constructing these outside the context of rare diseases or cancer is limited. We piloted an approach for developing an ECA in Crohn's disease using electronic health records (EHR) data. METHODS: We queried EHR databases and manually screened records at the University of California, San Francisco to identify patients meeting the eligibility criteria of TRIDENT, a recently completed interventional trial involving an ustekinumab reference arm. We defined timepoints to balance missing data and bias. We compared imputation models by their impacts on cohort membership and outcomes. We assessed the accuracy of algorithmic data curation against manual review. Lastly, we assessed disease activity following treatment with ustekinumab. RESULTS: Screening identified 183 patients. 30% of the cohort had missing baseline data. Nonetheless, cohort membership and outcomes were robust to the method of imputation. Algorithms for ascertaining non-symptom-based elements of disease activity using structured data were accurate against manual review. The cohort consisted of 56 patients, exceeding planned enrollment in TRIDENT. 34% of the cohort was in steroid-free remission at week 24. CONCLUSION: We piloted an approach for creating an ECA in Crohn's disease from EHR data by using a combination of informatics and manual methods. However, our study reveals significant missing data when standard-of-care clinical data are repurposed. More work will be needed to improve the alignment of trial design with typical patterns of clinical practice, and thereby enable a future of more robust ECAs in chronic diseases like Crohn's disease.
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Enfermedad de Crohn , Ustekinumab , Humanos , Ustekinumab/uso terapéutico , Enfermedad de Crohn/tratamiento farmacológico , Proyectos Piloto , Registros Electrónicos de Salud , Estudios Prospectivos , Estudios RetrospectivosRESUMEN
The SARS-CoV-2 Omicron variant of concern (VoC) and its sublineages contain 31-36 mutations in spike and escape neutralization by most therapeutic antibodies. In a pseudovirus neutralization assay, 66 of the nearly 400 candidate therapeutics in the Coronavirus Immunotherapeutic Consortium (CoVIC) panel neutralize Omicron and multiple Omicron sublineages. Among natural immunoglobulin Gs (IgGs), especially those in the receptor-binding domain (RBD)-2 epitope community, nearly all Omicron neutralizers recognize spike bivalently, with both antigen-binding fragments (Fabs) simultaneously engaging adjacent RBDs on the same spike. Most IgGs that do not neutralize Omicron bind either entirely monovalently or have some (22%-50%) monovalent occupancy. Cleavage of bivalent-binding IgGs to Fabs abolishes neutralization and binding affinity, with disproportionate loss of activity against Omicron pseudovirus and spike. These results suggest that VoC-resistant antibodies overcome mutagenic substitution via avidity. Hence, vaccine strategies targeting future SARS-CoV-2 variants should consider epitope display with spacing and organization identical to trimeric spike.
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COVID-19 , Humanos , SARS-CoV-2 , Etnicidad , Epítopos , Anticuerpos Antivirales , Anticuerpos Neutralizantes , Pruebas de NeutralizaciónRESUMEN
BACKGROUND: Pulmonary hypertension (PH) is life-threatening, and often diagnosed late in its course. We aimed to evaluate if a deep learning approach using electrocardiogram (ECG) data alone can detect PH and clinically important subtypes. We asked: does an automated deep learning approach to ECG interpretation detect PH and its clinically important subtypes? METHODS AND RESULTS: Adults with right heart catheterization or an echocardiogram within 90 days of an ECG at the University of California, San Francisco (2012-2019) were retrospectively identified as PH or non-PH. A deep convolutional neural network was trained on patients' 12-lead ECG voltage data. Patients were divided into training, development, and test sets in a ratio of 7:1:2. Overall, 5016 PH and 19,454 patients without PH were used in the study. The mean age at the time of ECG was 62.29 ± 17.58 years and 49.88% were female. The mean interval between ECG and right heart catheterization or echocardiogram was 3.66 and 2.23 days for patients with PH and patients without PH, respectively. In the test dataset, the model achieved an area under the receiver operating characteristic curve, sensitivity, and specificity, respectively of 0.89, 0.79, and 0.84 to detect PH; 0.91, 0.83, and 0.84 to detect precapillary PH; 0.88, 0.81, and 0.81 to detect pulmonary arterial hypertension, and 0.80, 0.73, and 0.76 to detect group 3 PH. We additionally applied the trained model on ECGs from participants in the test dataset that were obtained from up to 2 years before diagnosis of PH; the area under the receiver operating characteristic curve was 0.79 or greater. CONCLUSIONS: A deep learning ECG algorithm can detect PH and PH subtypes around the time of diagnosis and can detect PH using ECGs that were done up to 2 years before right heart catheterization/echocardiogram diagnosis. This approach has the potential to decrease diagnostic delays in PH.
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Aprendizaje Profundo , Insuficiencia Cardíaca , Hipertensión Pulmonar , Adulto , Humanos , Femenino , Masculino , Hipertensión Pulmonar/diagnóstico , Estudios Retrospectivos , Electrocardiografía/métodosRESUMEN
In fall, alate males of the potato aphid, Macrosiphum euphorbiae (Thomas), migrate from their summer (secondary) host plants, such as potatoes, to primary host plants, such as roses, where they mate with wingless oviparae who produce the overwintering egg stage. Males are weak fliers and generally walk towards a pheromone source under windy conditions, so we tested the hypothesis that upwind walking behaviour in response to wind velocity would be affected by the volatile cues present. We compared male responses to the odour of a rugosa rose cutting alone and to the combination of host plant volatiles and the female sex pheromone under a range of wind speeds in a laboratory walking bioassay. The proportion of males responding decreased as the wind speed increased, but at all wind velocities, the responses to the combined odours were higher than to the host plant alone. However, at any given wind velocity, the speed at which responding aphids moved was not influenced by the odour source. These findings support the idea that host plant volatiles serve as long-distance cues for males and that the female sex pheromone is used once on the host plant.
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The special issue editors selected us to form an "adversarial collaboration" because our publications and teaching encompass both supportive and critical attitudes toward the Rorschach and its recently developed system for use, the Rorschach Performance Assessment System (R-PAS). We reviewed the research literature and case law to determine if the Rorschach and specifically R-PAS meet legal standards for admissibility in court. We included evidence on norms, reliability, validity, utility, general acceptance, forensic evaluator use, and response style assessment, as well as United States and selected European case law addressing challenges to mental examination motions, admissibility, and weight. Compared to other psychological tests, the Rorschach is not challenged at unusually high rates. Although the recently introduced R-PAS is not widely referenced in case law, evidence suggests that information from it is likely to be ruled admissible when used by a competent evaluator and selected variables yield scores that are sufficiently reliable and valid to evaluate psychological processes that inform functional psycholegal capacities. We identify effective and ethical but also inappropriate uses (e.g., psychological profiling) of R-PAS in criminal, civil, juvenile, and family court. We recommend specific research to clarify important aspects of R-PAS and advance its utility in forensic mental health assessment.
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Criminales , Humanos , Pruebas Psicológicas , Reproducibilidad de los Resultados , Estados UnidosRESUMEN
Understanding microbial gene functions relies on the application of experimental genetics in cultured microorganisms. However, the vast majority of bacteria and archaea remain uncultured, precluding the application of traditional genetic methods to these organisms and their interactions. Here, we characterize and validate a generalizable strategy for editing the genomes of specific organisms in microbial communities. We apply environmental transformation sequencing (ET-seq), in which nontargeted transposon insertions are mapped and quantified following delivery to a microbial community, to identify genetically tractable constituents. Next, DNA-editing all-in-one RNA-guided CRISPR-Cas transposase (DART) systems for targeted DNA insertion into organisms identified as tractable by ET-seq are used to enable organism- and locus-specific genetic manipulation in a community context. Using a combination of ET-seq and DART in soil and infant gut microbiota, we conduct species- and site-specific edits in several bacteria, measure gene fitness in a nonmodel bacterium and enrich targeted species. These tools enable editing of microbial communities for understanding and control.
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Microbioma Gastrointestinal/genética , Edición Génica/métodos , Genoma Bacteriano , Consorcios Microbianos/genética , Microbiología del Suelo , Archaea/genética , Bacterias/clasificación , Sistemas CRISPR-Cas , Humanos , Lactante , ARN Guía de KinetoplastidaRESUMEN
The evolution of mass raiding has allowed army ants to become dominant arthropod predators in the tropics. Although a century of research has led to many discoveries about behavioural, morphological and physiological adaptations in army ants, almost nothing is known about the molecular basis of army ant biology. Here we report the genome of the iconic New World army ant Eciton burchellii, and show that it is unusually compact, with a reduced gene complement relative to other ants. In contrast to this overall reduction, a particular gene subfamily (9-exon ORs) expressed predominantly in female antennae is expanded. This subfamily has previously been linked to the recognition of hydrocarbons, key olfactory cues used in insect communication and prey discrimination. Confocal microscopy of the brain showed a corresponding expansion in a putative hydrocarbon response centre within the antennal lobe, while scanning electron microscopy of the antenna revealed a particularly high density of hydrocarbon-sensitive sensory hairs. E. burchellii shares these features with its predatory and more cryptic relative, the clonal raider ant. By integrating genomic, transcriptomic and anatomical analyses in a comparative context, our work thus provides evidence that army ants and their relatives possess a suite of modifications in the chemosensory system that may be involved in behavioural coordination and prey selection during social predation. It also lays the groundwork for future studies of army ant biology at the molecular level.
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Hormigas , Adaptación Fisiológica , Animales , Hormigas/genética , Femenino , Genoma , Genómica , Conducta PredatoriaRESUMEN
Understanding the regulatory architecture of phenotypic variation is a fundamental goal in biology, but connections between gene regulatory network (GRN) activity and individual differences in behavior are poorly understood. We characterized the molecular basis of behavioral plasticity in queenless honey bee (Apis mellifera) colonies, where individuals engage in both reproductive and non-reproductive behaviors. Using high-throughput behavioral tracking, we discovered these colonies contain a continuum of phenotypes, with some individuals specialized for either egg-laying or foraging and 'generalists' that perform both. Brain gene expression and chromatin accessibility profiles were correlated with behavioral variation, with generalists intermediate in behavior and molecular profiles. Models of brain GRNs constructed for individuals revealed that transcription factor (TF) activity was highly predictive of behavior, and behavior-associated regulatory regions had more TF motifs. These results provide new insights into the important role played by brain GRN plasticity in the regulation of behavior, with implications for social evolution.
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Abejas/fisiología , Conducta Animal/fisiología , Encéfalo/fisiología , Redes Reguladoras de Genes , Plasticidad Neuronal/fisiología , Animales , Individualidad , Fenotipo , Conducta Social , Factores de Transcripción/metabolismoRESUMEN
Endotheliitis is the inflammation of the corneal endothelium resulting in edema and subsequent loss of vision. Bacterial causes of corneal inflammation primarily of the epithelium with subsequent, secondary involvement of the endothelium have previously been described. Notably, however, there are no reports of isolated endotheliitis related to a bacterial pathogen. We report, for the first time, a case of corneal endotheliitis associated with a pyogenic liver abscess caused by methicillin resistant Staphylococcus aureus (MRSA). Treatment targeting the underlying source of infection led to visual recovery in our patient.
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The cyanobacterium Synechococcus elongatus is a model organism for the study of circadian rhythms. It is naturally competent for transformation-that is, it takes up DNA from the environment, but the underlying mechanisms are unclear. Here, we use a genome-wide screen to identify genes required for natural transformation in S. elongatus, including genes encoding a conserved Type IV pilus, genes known to be associated with competence in other bacteria, and others. Pilus biogenesis occurs daily in the morning, while natural transformation is maximal when the onset of darkness coincides with the dusk circadian peak. Thus, the competence state in cyanobacteria is regulated by the circadian clock and can adapt to seasonal changes of day length.
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Relojes Circadianos/fisiología , Fimbrias Bacterianas/metabolismo , Synechococcus/fisiología , Transformación Bacteriana/fisiología , Adaptación Fisiológica/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Péptidos y Proteínas de Señalización del Ritmo Circadiano/genética , Péptidos y Proteínas de Señalización del Ritmo Circadiano/metabolismo , Elementos Transponibles de ADN/genética , Oscuridad , Regulación Bacteriana de la Expresión Génica/fisiología , Transferencia de Gen Horizontal , Modelos Biológicos , Mutación , Estaciones del Año , Factores de Transcripción/metabolismoRESUMEN
Objective: Undergoing mild traumatic brain injury (mTBI) increases mortality risk, but it is unclear what drives this finding. This study explored associations with mortality in patients with mTBI.Methods: This was a retrospective study of patients with mTBI and controls admitted to six level 1 trauma centers in 1/1/2009-12/31/2013. Mortality data were from the CDC National Death Index. Patients with mTBI were identified by ICD-9 code, Glasgow Coma Scale 13-15, Injury Severity Score (ISS) <16, and loss of consciousness ≤1 hour. Controls had hospital length of stay ≤24 hours, ISS<16, and no head injury.Results: This study included 964 patients with mTBI and 5,567 controls. mTBI was associated with a 47% increased 5-year mortality risk (HR = 1.47, 95% CL 1.08-2.01). Patients with mTBI were more likely to die of a neurodegenerative disease (17% vs 11%, P = .119). Cardiovascular (HR = 1.80, 95% CL 1.17-2.77), neurological (HR = 3.33, 95% CL 2.07-5.38), and respiratory (HR = 1.70, 95% CL 1.01-2.86) comorbidities were associated with mortality in patients with mTBI.Conclusions: Patients with mTBI are at increased mortality risk in the 5 years post-injury. Mortality in patients with mTBI was most influenced by preexisting conditions.
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Conmoción Encefálica , Enfermedades Neurodegenerativas , Causas de Muerte , Escala de Coma de Glasgow , Humanos , Estudios RetrospectivosRESUMEN
Background: Advanced aged adults have the highest rate of traumatic brain injury (TBI) related hospital admissions, compared to younger age groups. Data were published in 2014 indicating differential injury and neurological responses to a TBI by age categories. In a recent article examining patients with mTBI and isolated subdural hematoma, it was found that older patients had a decreased risk of documented loss of consciousness (LOC). The primary objective was to determine the extent to which the odds of documented LOC changes with increasing age in a population of older adults suffering an isolated concussion and uncomplicated mTBI. Methods: This was a retrospective study utilizing 6 years (2010-2015) of National Trauma Data Bank data. This study included patients with (1) diagnosis of concussion; (2) positive or negative loss of consciousness; (3) loss of consciousness durations no longer than 59 min or undefined; (4) age ≥50 years; (5) had a "fall" mechanism of injury; and (6) a valid emergency department Glasgow coma scale 13-15. We excluded patients (1) with any intracranial hemorrhage or intracranial injury of other and unspecified nature; (2) skull fracture; (3) an injury severity scale score >17; (4) a concussion with "unspecified" LOC (ICD-9: 850.9). Results: There were 7,466 patients included in the study; the median (IQR) age was 70 (60-80) years. The risk of documented LOC was 71% (n = 5,319). An 80-year-old had 72% decreased odds of having a documented LOC, compared to a 50-year-old (OR = 0.28, 99.5%CI [0.23-0.34], P < 0.001). This association held when controlling for multiple demographic, comorbid, and clinical variables, and in sensitivity analyses. Conclusion: These nationwide data suggest that in patients aged ≥50 years, a significant inverse association exists between age and odds of documented LOC after sustaining a fall-related concussion. Additional studies are needed to validate these findings and to investigate the triad of age, documented LOC, and intracranial hemorrhage. Clinical diagnostic criteria relying on LOC might be at risk of being modified by the association between increasing age and decreasing odds of LOC.
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The evolutionary origins of eusociality represent increases in complexity from individual to caste-based, group reproduction. These behavioural transitions have been hypothesized to go hand in hand with an increased ability to regulate when and where genes are expressed. Bees have convergently evolved eusociality up to five times, providing a framework to test this hypothesis. To examine potential links between putative gene regulatory elements and social evolution, we compare alignable, non-coding sequences in 11 diverse bee species, encompassing three independent origins of reproductive division of labour and two elaborations of eusocial complexity. We find that rates of evolution in a number of non-coding sequences correlate with key social transitions in bees. Interestingly, while we find little evidence for convergent rate changes associated with independent origins of social behaviour, a number of molecular pathways exhibit convergent rate changes in conjunction with subsequent elaborations of social organization. We also present evidence that many novel non-coding regions may have been recruited alongside the origin of sociality in corbiculate bees; these loci could represent gene regulatory elements associated with division of labour within this group. Thus, our findings are consistent with the hypothesis that gene regulatory innovations are associated with the evolution of eusociality and illustrate how a thorough examination of both coding and non-coding sequence can provide a more complete understanding of the molecular mechanisms underlying behavioural evolution. This article is part of the theme issue 'Convergent evolution in the genomics era: new insights and directions'.
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Abejas/genética , Evolución Molecular , Regiones no Traducidas , Animales , Abejas/clasificación , Abejas/fisiología , Conducta Animal , ADN/genética , Femenino , Masculino , Filogenia , Reproducción , Conducta SocialRESUMEN
Weather has been recognized as a density independent factor influencing the abundance, distribution, and behavior of vertebrates. Male wild turkeys' (Meleagris gallopavo) breeding behavior includes vocalizations and courtship displays to attract females, the phenology of which can vary with latitude. State biologists design spring turkey-hunting season frameworks centered on annual vocalization patterns to maximize hunter engagement. The Mississippi Department of Wildlife, Fisheries, and Parks has traditionally instituted a statewide, 7-week, spring harvest season. However, hunters routinely argue that different peaks in gobbling activity across the state exist. The objective of this study was to determine whether differences in peak gobbling activity existed across a latitudinal gradient of Mississippi and assess the effect of weather on gobbling. During 2008 and 2009, we conducted a statewide gobbling survey. We used generalized additive mixed models to describe the probability and frequency of gobbling activity within northern and southern regions of the state. We also investigated the effect of daily weather conditions on gobbling activity. Our results revealed an approximate 10-14-day difference in peak gobbling activity between southern and northern Mississippi. The majority of all gobbling activity occurred within the current spring harvest framework. Perhaps more importantly, gobbling activity was more prevalent on days of regionally dry conditions (i.e., less humid) according to the Spatial Synoptic Classification. Our results provide information on gobbling activity phenology relative to hunting-season dates and weather-response information. Our approach may be particularly applicable in states with relatively shorter seasons or highly variable daily weather conditions that moderate gobbling frequency.
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Pavos , Tiempo (Meteorología) , Animales , Animales Salvajes , Femenino , Masculino , Probabilidad , Estaciones del AñoRESUMEN
Animals select resources to maximize fitness but associated costs and benefits are spatially and temporally variable. Differences in wetland management influence resource availability for ducks and mortality risk from duck hunting. The local distribution of the Mallard (Anas platyrhynchos) is affected by this resource heterogeneity and variable risk from hunting. Regional conservation strategies primarily focus on how waterfowl distributions are affected by food resources during the nonbreeding season. To test if Mallard resource selection was related to the abundance of resources, risks, or a combination, we studied resource selection of adult female Mallards during autumn and winter. We developed a digital spatial layer for Lake St. Clair, Ontario, Canada, that classified resources important to Mallards and assigned these resources a risk level based on ownership type and presumed disturbance from hunting. We monitored 59 individuals with GPS back-pack transmitters prior to, during, and after the hunting season and used discrete choice modeling to generate diurnal and nocturnal resource selection estimates. The model that classified available resources and presumed risk best explained Mallard resource selection strategies. Resource selection varied within and among seasons. Ducks selected for federal, state and private managed wetland complexes that provided an intermediate or relatively greater amount of refuge and foraging options than public hunting areas. Across all diel periods and seasons, there was selection for federally managed marshes and private supplemental feeding refuges that prohibited hunting. Mallard resource selection demonstrated trade-offs related to the management of mortality risk, anthropogenic disturbances, and foraging opportunities. Understanding how waterfowl respond to heterogeneous landscapes of resources and risks can inform regional conservation strategies related to waterfowl distribution during the nonbreeding season.