SARS-CoV-2 Omicron XBB lineage spike structures, conformations, antigenicity, and receptor recognition.

A recombinant lineage of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant, named XBB, appeared in late 2022 and evolved descendants that successively swept local and global populations. XBB lineage members were noted for their improved immune evasion and transmissibility. Here, we determine cryoelectron microscopy (cryo-EM) structures of XBB.1.5, XBB.1.16, EG.5, and EG.5.1 spike (S) ectodomains to reveal reinforced 3-receptor binding domain (RBD)-down receptor-inaccessible closed states mediated by interprotomer RBD interactions previously observed in BA.1 and BA.2. Improved XBB.1.5 and XBB.1.16 RBD stability compensated for stability loss caused by early Omicron mutations, while the F456L substitution reduced EG.5 RBD stability. S1 subunit mutations had long-range impacts on conformation and epitope presentation in the S2 subunit. Our results reveal continued S protein evolution via simultaneous optimization of multiple parameters, including stability, receptor binding, and immune evasion, and the dramatic effects of relatively few residue substitutions in altering the S protein conformational landscape.

Mosquito taste responses to human and floral cues guide biting and feeding.

The taste system controls many insect behaviours, yet little is known about how tastants are encoded in mosquitoes or how they regulate critical behaviours. Here we examine how taste stimuli are encoded by Aedes albopictus mosquitoes-a highly invasive disease vector-and how these cues influence biting, feeding and egg laying. We find that neurons of the labellum, the major taste organ of the head, differentially encode a wide variety of human and other cues. We identify three functional classes of taste sensilla with an expansive coding capacity. In addition to excitatory responses, we identify prevalent inhibitory responses, which are predictive of biting behaviour. Certain bitter compounds suppress physiological and behavioural responses to sugar, suggesting their use as potent stop signals against appetitive cues. Complex cues, including human sweat, nectar and egg-laying site water, elicit distinct response profiles from the neuronal repertoire. We identify key tastants on human skin and in sweat that synergistically promote biting behaviours. Transcriptomic profiling identifies taste receptors that could be targeted to disrupt behaviours. Our study sheds light on key features of the taste system that suggest new ways of manipulating chemosensory function and controlling mosquito vectors.

Functional genomics in inborn errors of immunity.

Inborn errors of immunity (IEI) comprise a diverse spectrum of 485 disorders as recognized by the International Union of Immunological Societies Committee on Inborn Error of Immunity in 2022. While IEI are monogenic by definition, they illuminate various pathways involved in the pathogenesis of polygenic immune dysregulation as in autoimmune or autoinflammatory syndromes, or in more common infectious diseases that may not have a significant genetic basis. Rapid improvement in genomic technologies has been the main driver of the accelerated rate of discovery of IEI and has led to the development of innovative treatment strategies. In this review, we will explore various facets of IEI, delving into the distinctions between PIDD and PIRD. We will examine how Mendelian inheritance patterns contribute to these disorders and discuss advancements in functional genomics that aid in characterizing new IEI. Additionally, we will explore how emerging genomic tools help to characterize new IEI as well as how they are paving the way for innovative treatment approaches for managing and potentially curing these complex immune conditions.

Point mutation in a virus-like capsid drives symmetry reduction to form tetrahedral cages.

Protein capsids are a widespread form of compartmentalization in nature. Icosahedral symmetry is ubiquitous in capsids derived from spherical viruses, as this geometry maximizes the internal volume that can be enclosed within. Despite the strong preference for icosahedral symmetry, we show that simple point mutations in a virus-like capsid can drive the assembly of unique symmetry-reduced structures. Starting with the encapsulin from Myxococcus xanthus, a 180-mer bacterial capsid that adopts the well-studied viral HK97 fold, we use mass photometry and native charge detection mass spectrometry to identify a triple histidine point mutant that forms smaller dimorphic assemblies. Using cryoelectron microscopy, we determine the structures of a precedented 60-mer icosahedral assembly and an unexpected 36-mer tetrahedron that features significant geometric rearrangements around a new interaction surface between capsid protomers. We subsequently find that the tetrahedral assembly can be generated by triple-point mutation to various amino acids and that even a single histidine point mutation is sufficient to form tetrahedra. These findings represent a unique example of tetrahedral geometry when surveying all characterized encapsulins, HK97-like capsids, or indeed any virus-derived capsids reported in the Protein Data Bank, revealing the surprising plasticity of capsid self-assembly that can be accessed through minimal changes in the protein sequence.

The thermoneutral zone in women takes an "arctic" shift compared to men.

Conventionally, women are perceived to feel colder than men, but controlled comparisons are sparse. We measured the response of healthy, lean, young women and men to a range of ambient temperatures typical of the daily environment (17 to 31 °C). The Scholander model of thermoregulation defines the lower critical temperature as threshold of the thermoneutral zone, below which additional heat production is required to defend core body temperature. This parameter can be used to characterize the thermoregulatory phenotypes of endotherms on a spectrum from "arctic" to "tropical." We found that women had a cooler lower critical temperature (mean ± SD: 21.9 ± 1.3 °C vs. 22.9 ± 1.2 °C, P = 0.047), resembling an "arctic" shift compared to men. The more arctic profile of women was predominantly driven by higher insulation associated with more body fat compared to men, countering the lower basal metabolic rate associated with their smaller body size, which typically favors a "tropical" shift. We did not detect sex-based differences in secondary measures of thermoregulation including brown adipose tissue glucose uptake, muscle electrical activity, skin temperatures, cold-induced thermogenesis, or self-reported thermal comfort. In conclusion, the principal contributors to individual differences in human thermoregulation are physical attributes, including body size and composition, which may be partly mediated by sex.

Retinoic acid is dispensable for meiotic initiation but required for spermiogenesis in the mammalian testis.

Retinoic acid (RA) is the proposed mammalian 'meiosis inducing substance'. However, evidence for this role comes from studies in the fetal ovary, where germ cell differentiation and meiotic initiation are temporally inseparable. In the postnatal testis, these events are separated by more than 1 week. Exploiting this difference, we discovered that, although RA is required for spermatogonial differentiation, it is dispensable for the subsequent initiation, progression and completion of meiosis. Indeed, in the absence of RA, the meiotic transcriptome program in both differentiating spermatogonia and spermatocytes entering meiosis was largely unaffected. Instead, transcripts encoding factors required during spermiogenesis were aberrant during preleptonema, and the subsequent spermatid morphogenesis program was disrupted such that no sperm were produced. Taken together, these data reveal a RA-independent model for male meiotic initiation.

Isolation and characterization of IgG3 glycan-targeting antibodies with exceptional cross-reactivity for diverse viral families.

Broadly reactive antibodies that target sequence-diverse antigens are of interest for vaccine design and monoclonal antibody therapeutic development because they can protect against multiple strains of a virus and provide a barrier to evolution of escape mutants. Using LIBRA-seq (linking B cell receptor to antigen specificity through sequencing) data for the B cell repertoire of an individual chronically infected with human immunodeficiency virus type 1 (HIV-1), we identified a lineage of IgG3 antibodies predicted to bind to HIV-1 Envelope (Env) and influenza A Hemagglutinin (HA). Two lineage members, antibodies 2526 and 546, were confirmed to bind to a large panel of diverse antigens, including several strains of HIV-1 Env, influenza HA, coronavirus (CoV) spike, hepatitis C virus (HCV) E protein, Nipah virus (NiV) F protein, and Langya virus (LayV) F protein. We found that both antibodies bind to complex glycans on the antigenic surfaces. Antibody 2526 targets the stem region of influenza HA and the N-terminal domain (NTD) region of SARS-CoV-2 spike. A crystal structure of 2526 Fab bound to mannose revealed the presence of a glycan-binding pocket on the light chain. Antibody 2526 cross-reacted with antigens from multiple pathogens and displayed no signs of autoreactivity. These features distinguish antibody 2526 from previously described glycan-reactive antibodies. Further study of this antibody class may aid in the selection and engineering of broadly reactive antibody therapeutics and can inform the development of effective vaccines with exceptional breadth of pathogen coverage.

Parallels and contrasts between the cnidarian and bilaterian maternal-to-zygotic transition are revealed in Hydractinia embryos.

Embryogenesis requires coordinated gene regulatory activities early on that establish the trajectory of subsequent development, during a period called the maternal-to-zygotic transition (MZT). The MZT comprises transcriptional activation of the embryonic genome and post-transcriptional regulation of egg-inherited maternal mRNA. Investigation into the MZT in animals has focused almost exclusively on bilaterians, which include all classical models such as flies, worms, sea urchin, and vertebrates, thus limiting our capacity to understand the gene regulatory paradigms uniting the MZT across all animals. Here, we elucidate the MZT of a non-bilaterian, the cnidarian Hydractinia symbiolongicarpus. Using parallel poly(A)-selected and non poly(A)-dependent RNA-seq approaches, we find that the Hydractinia MZT is composed of regulatory activities similar to many bilaterians, including cytoplasmic readenylation of maternally contributed mRNA, delayed genome activation, and separate phases of maternal mRNA deadenylation and degradation that likely depend on both maternally and zygotically encoded clearance factors, including microRNAs. But we also observe massive upregulation of histone genes and an expanded repertoire of predicted H4K20 methyltransferases, aspects thus far particular to the Hydractinia MZT and potentially underlying a novel mode of early embryonic chromatin regulation. Thus, similar regulatory strategies with taxon-specific elaboration underlie the MZT in both bilaterian and non-bilaterian embryos, providing insight into how an essential developmental transition may have arisen in ancestral animals.

The SWI/SNF chromatin remodeling assemblies BAF and PBAF differentially regulate cell cycle exit and cellular invasion in vivo.

Chromatin remodelers such as the SWI/SNF complex coordinate metazoan development through broad regulation of chromatin accessibility and transcription, ensuring normal cell cycle control and cellular differentiation in a lineage-specific and temporally restricted manner. Mutations in genes encoding the structural subunits of chromatin, such as histone subunits, and chromatin regulating factors are associated with a variety of disease mechanisms including cancer metastasis, in which cancer co-opts cellular invasion programs functioning in healthy cells during development. Here we utilize Caenorhabditis elegans anchor cell (AC) invasion as an in vivo model to identify the suite of chromatin agents and chromatin regulating factors that promote cellular invasiveness. We demonstrate that the SWI/SNF ATP-dependent chromatin remodeling complex is a critical regulator of AC invasion, with pleiotropic effects on both G0 cell cycle arrest and activation of invasive machinery. Using targeted protein degradation and enhanced RNA interference (RNAi) vectors, we show that SWI/SNF contributes to AC invasion in a dose-dependent fashion, with lower levels of activity in the AC corresponding to aberrant cell cycle entry and increased loss of invasion. Our data specifically implicate the SWI/SNF BAF assembly in the regulation of the G0 cell cycle arrest in the AC, whereas the SWI/SNF PBAF assembly promotes AC invasion via cell cycle-independent mechanisms, including attachment to the basement membrane (BM) and activation of the pro-invasive fos-1/FOS gene. Together these findings demonstrate that the SWI/SNF complex is necessary for two essential components of AC invasion: arresting cell cycle progression and remodeling the BM. The work here provides valuable single-cell mechanistic insight into how the SWI/SNF assemblies differentially contribute to cellular invasion and how SWI/SNF subunit-specific disruptions may contribute to tumorigeneses and cancer metastasis.

A simple method to dramatically increase C. elegans germline microinjection efficiency.

Genome manipulation methods in C. elegans require microinjecting DNA or ribonucleoprotein complexes into the microscopic core of the gonadal syncytium. These microinjections are technically demanding and represent a key bottleneck for all genome engineering and transgenic approaches in C. elegans. While there have been steady improvements in the ease and efficiency of genetic methods for C. elegans genome manipulation, there have not been comparable advances in the physical process of microinjection. Here, we report a simple and inexpensive method for handling worms using a paintbrush during the injection process that nearly tripled average microinjection rates compared to traditional worm handling methods. We found that the paintbrush increased injection throughput by substantially increasing both injection speeds and post-injection survival rates. In addition to dramatically and universally increasing injection efficiency for experienced personnel, the paintbrush method also significantly improved the abilities of novice investigators to perform key steps in the microinjection process. We expect that this method will benefit the C. elegans community by increasing the speed at which new strains can be generated and will also make microinjection-based approaches less challenging and more accessible to personnel and labs without extensive experience.

Predicting Phase Stability at Interfaces.

We present the RAFFLE methodology for structural prediction of the interface between two materials and demonstrate its effectiveness by applying it to MgO encapsulated by two layers of graphene. To address the challenge of interface structure prediction, our methodology combines physical insights derived from morphological features observed in related systems with an iterative machine learning technique. This employs physical-based methods, including void-filling and n-body distribution functions to predict interface structures. For the carbon-MgO encapsulated system, we have shown the rocksalt and hexagonal phases of MgO to be the two most energetically stable in the few-layer regime. We demonstrate that monolayer rocksalt is heavily stabilized by interfacing with graphene, becoming more energetically favorable than the graphenelike monolayer hexagonal MgO. The RAFFLE methodology provides valuable insights into interface behavior, and a route to finding new materials at interfaces.

Predicting psychosocial intervention response from baseline gene expression.

To address the challenge of predicting psychological response to a psychosocial intervention we tested the possibility that baseline gene expression profiles might provide information above and beyond baseline psychometric measures. The genomics strategy utilized individual level inferences of transcription factor activity to predict changes in loneliness and affect in response to two well-established meditation interventions. Initial algorithm development analyses focused on three a-priori defined stress-related gene regulation pathways (CREB, GR, and NF-ĸB) as inferred from TELiS promoter-based bioinformatic analysis of basal (pre-intervention) blood samples from a randomized-controlled trial comparing a compassion-based meditation (CM, n = 45) with mindfulness meditation (MM, n = 44). Greater baseline CREB activity (but not GR or NF-ĸB) predicted greater reductions from pre- to post-intervention in loneliness (b = -0.24, p = 0.016) and negative emotions (b = -0.23, p = 0.017) for CM, but not for MM. A second algorithm validation analysis applied the same approach to another randomized controlled trial comparing CM (n = 42) with MM (n = 38) and a health education control condition (n = 41). Similarly, greater baseline CREB activity predicted greater pre- to post-intervention decreases in loneliness (b = -0.24, p = 0.029) and greater increases in satisfaction with life (b = 0.21, p = 0.046) for the CM condition only. Baseline CREB activity was not associated with baseline psychometric measures in either study. Results raise the possibility that pre-intervention gene expression profiles may reflect non-conscious psychobiological states that affect psychological responses to distinct psychosocial interventions, and thereby help personalize intervention selection.

Differential effects of social versus monetary incentives on inhibitory control under acute inflammation.

While the impact of chronic, low-grade inflammation on cognitive functioning is documented in the context of neurodegenerative disease, less is known about the association between acute increases in inflammation and cognitive functioning in daily life. This study investigated how changes in interleukin-6 (IL-6) levels were associated with performance on an inhibitory control task, the go/no-go task. We further examined whether the opportunity to earn different incentive types (social or monetary) and magnitudes (high or low) was associated with differential performance on the task, depending on IL-6 levels. Using a within-participant design, individuals completed an incentivized go/no-go task before and after receiving the annual influenza vaccine. Multilevel logistic regressions were performed on the trial-level data (Nobs = 30,528). For no-go trials, we did not find significant associations between IL and 6 reactivity between the sessions and changes in trial accuracy. For go trials, we found significant differences in the associations between IL and 6 reactivity and changes in accuracy from session 1 to session 2 as a function of the incentive condition. Notably, greater IL-6 reactivity was consistently associated with fewer omission errors (i.e., greater accuracy on go trials) on high-magnitude social incentives (i.e., viewing a picture of a close-other picture) when compared to both low-magnitude social and high-magnitude monetary incentives. Together, these results suggest that mild fluctuations in inflammation might alter the valuation of an incentive, and possibly a shift toward devoting greater attentional resources when a large social incentive is on the line. Overall, this study sheds light on how everyday, low-grade fluctuations in inflammation may influence cognitive abilities essential for daily life and effective inhibitory control.

Motor and Non-Motor Factors of Concern About Falling and Fear of Falling in Multiple Sclerosis.

BACKGROUND AND PURPOSE: Despite the frequency of concern about falling (CAF) and fear of falling (FOF) in multiple sclerosis (MS), there remains a lack of clarity between FOF and CAF, though persons with MS have indicated that CAF and FOF are distinct constructs. Our team previously developed and validated a new questionnaire, the Concern and Fear of Falling Evaluation (CAFFE), to assess these concepts. This study aimed to examine CAF and FOF prevalence, and determine relationships among CAF, FOF, and self-reported motor, cognitive, and psychological function in MS relapsing (RRMS) and progressive (PMS) subtypes. METHODS: In a single online survey, participants with MS completed questions about CAF and FOF, demographic information, the CAFFE, and self-report measures of motor, cognitive, and psychological function. RESULTS: A total of 912 individuals completed the survey. Persons with PMS reported greater CAF (80.1%) and FOF (59.1%) than those with RRMS (57.0% and 41.6%, respectively). Persons with PMS endorsing FOF (yes/no) reported greater FOF on the CAFFE, greater avoidance behavior, greater walking impairment, and poorer motor function than people with RRMS ( P < 0.001). Self-reported motor function, walking impairment, and avoidance behavior were highly correlated to the CAFFE across the overall sample ( P < 0.001). DISCUSSIONS AND CONCLUSIONS: These findings underscore the disparity between CAF and FOF, emphasize the importance of evaluating CAF and FOF in MS subtypes separately, and highlight both motor and non-motor factors contributing to CAF and FOF. Future work should focus on interventions that incorporate motor, cognitive, and psychological components to address CAF and FOF. VIDEO ABSTRACT: for more insights from the authors Supplemental Digital Content available at http://links.lww.com/JNPT/A481 .

Concordance in dietary intake among caregivers and infants during the period of complementary feeding: A scoping review.

Dietary intake during infancy shapes later food preferences and is important for short- and long-term health and wellbeing. Although caregivers are thought to influence the developing food preferences of infants, children less than two years have been notably absent in existing meta-analyses on the topic. This scoping review seeks to fill this gap by using a systematic process to identify and summarize the published literature on the resemblance of caregiver and infant diet during the period of complementary feeding (6-23 months). Articles were included if they assessed intake of foods or beverages other than human milk or commercial milk formula and reported a test of association between the intake of caregivers and infants. Four electronic databases (PubMed, EMBASE, Scopus, and Global Health) were systematically searched for articles published since 2000. Thirty-three articles, representing 32 studies, were identified. The majority of studies examined infant intake of food groups/items (n = 20), seven studies examined infant dietary patterns, and six studies examined dietary diversity. Studies predominantly reported associations between diets of mothers and infants (n = 31); three studies reported associations for fathers. Most studies assessed infant diet at one timepoint (n = 26), with 12 studies combining the intakes of younger (0-11 months) and older infants (12-23 months). Food groups examined, in order of frequency, included 'non-core' foods and beverages (n = 14), vegetables (n = 13), fruits (n = 12), protein foods (n = 6), grains (n = 5), and dairy foods (n = 4). Definitions of variables for food groups and dietary patterns were highly heterogeneous, but consistent for dietary diversity. Nearly all studies (n = 31) reported significant associations between dietary intakes of caregivers and infants. Findings suggest caregiver diet may be a promising focus for interventions aiming to shape the food preferences and dietary intakes of infants.

Contraceptive risk events among family planning specialists: a cross sectional study.

BACKGROUND: Proponents of abortion restriction cite advancements in contraceptive technology as a reason against the need for abortion care today, most recently through oral arguments in the Supreme Court of the United States case, Dobbs v. Jackson Women's Health. However, consistent and correct use of contraception requires reproductive health literacy. Our objectives were to quantify contraceptive risk events and assess contraceptive history and preferences among a population well-equipped to evade contraceptive risks, family planning specialists following initiation of their medical training. "Risk events" are defined as reported episodes of contraceptive failure, emergency contraception use and/or unprotected or underprotected intercourse. METHODS: This was a cross-sectional study among current members of a professional organization of family planning specialists. Inclusion criteria included: status as a current or retired clinician, consensual penile-vaginal intercourse and personal or partner capacity to become pregnant since the start of medical training. Descriptive statistics were performed. This study was IRB exempt. RESULTS: Among 229 respondents, 157 (69%) reported experiencing a contraceptive risk event since training. Twenty-nine (13%) respondents reported an occurrence within the last year. By category, 47% (108/229; 3 reported unknown) reported under- or unprotected intercourse, 35% (81/229) reported emergency contraception use, and 52% of participants (117/227; 2 unknown) reported known or suspected contraceptive failure. The mean number of contraceptive methods used was 3.7 (SD 1.7) out of the 13 methods listed. Almost all (97%) participants reported at least one method was not an acceptable option, with a mean of 5.6 (SD 2.7) of the 13 listed methods. CONCLUSIONS: The majority of family planning specialists have experienced contraceptive risk events during times of active pregnancy prevention since their medical training. Contraceptive method change is common and most respondents were limited in the number of methods that were personally acceptable to them. Dialogue idealizing the role of contraception in minimizing or eliminating abortion need is simplistic and inaccurately represents the lived realities of pregnancy-capable individuals and their partners, including among those with exceptional contraceptive literacy and access.

ANTECEDENTES: Los que apoyan la restricción del aborto citan los avances en la tecnología anticonceptiva como una razón en contra de la necesidad de la atención del aborto hoy en día, más recientemente a través de los argumentos orales en el caso de la Corte Suprema de los Estados Unidos, Dobbs v. Jackson Women's Health. Sin embargo, el uso sistemático y indicado de los anticonceptivos requiere unos conocimientos sobre salud reproductive. Nuestros objetivos eran cuantificar los eventos de riesgo anticonceptivo y evaluar los antecedentes y las preferencias entre una población bien equipada para eludir los riesgos anticonceptivos, los especialistas en planificación familiar tras el inicio de su formación médica. Los "eventos de riesgo" se definen como episodios reportados de fallo anticonceptivo, uso de anticoncepción de emergencia y/o relaciones sexuales sin protección o con protección insuficiente. MéTODOS: Este fue un estudio transversal entre miembros actuales de una organización profesional de especialistas en planificación familiar. Los criterios de inclusión incluyeron: condición de clínico/a en activo/a o jubilado/a, relaciones sexuales consentidas pene-vagina desde el inicio de la formación médica y capacidad personal o de la pareja para quedarse embarazada. Se realizaron estadísticas descriptivas. Este estudio estaba exento de IRB. RESULTADOS: De las 229 encuestadas, 157 (69%) declararon haber sufrido un evento de riesgo anticonceptivo desde la formación. Veintinueve (13%) encuestadas declararon haberlo sufrido un incidente en el último año. Por categoría, el 47% (108/229; 3 informaron de forma desconocida) informaron de relaciones sexuales sin protección o con poca protección, el 35% (81/229) informaron del uso de anticonceptivos de emergencia y el 52% de los participantes (117/227; 2 informaron de forma desconocida) informaron de un fallo anticonceptivo conocido o sospechado. El promedio de métodos anticonceptivos utilizados fue 3,7 (DE 1,7) de los 13 métodos enumerados. Casi todas las participantes (97%) informaron de que al menos un método no era una opción aceptable, con un promedio de 5,6 (DE 2,7) de los 13 métodos enumerados. CONCLUSIONES: La mayoría de los especialistas en planificación familiar han experimentado eventos de riesgo anticonceptivo en momentos de prevención activa del embarazo desde su formación médica. El cambio de método anticonceptivo es frecuente y la mayoría de los encuestados tenían un número limitado de métodos que les resultaban personalmente aceptables. El diálogo que idealiza el papel de la planificación familiar a la hora de minimizar o eliminar la necesidad de abortar es simplista y representa de forma inexacta las realidades vividas por las personas con capacidad de embarazo y sus parejas, incluso entre aquellas con conocimientos y acceso excepcionales a la anticoncepción.

Impact of Neurostimulation, Immunomodulation, Topical Medication Application, and Surgical Reconstruction on Corneal Nerve Function and Regeneration.

ABSTRACT: The corneal epithelium, supplied by thousands of nerve endings, plays a substantial role in absorbing and distributing nutrients along the ocular surface. Many studies have explored the influence of various modalities in regulating tear production to manage corneal disorders and dry eye disease. These findings have highlighted the advantages of enhancing corneal nerve function and regeneration through neurostimulation, neural signaling, immunomodulation, topical medication application, and surgical reconstruction. The purpose of this narrative review article was to provide an overview of the current state of knowledge on this topic based on a PubMed database literature search for relevant animal and human studies investigating the modification of the trigeminal pathway to restore corneal nerve function and improve overall ocular health. Further investigation into this area of research is important to help guide new therapeutic targets for the prevention and development of treatments of corneal degeneration.

Male recognition of conspecific female chemical cues in a diverse clade of freshwater fishes.

Where orangethroat darters (Etheostoma: Ceasia) and rainbow darters (Etheostoma caeruleum) co-occur, males prefer conspecific over heterospecific females. The cues males use to identify conspecific females remain unclear. We conducted behavioral trials to ask whether chemical cues function in conspecific recognition. We found that males from three orangethroat darter species preferentially associate with female scent over a control. Our results support the use of olfaction in conspecific identification in the orangethroat clade and contribute to our understanding of signals that may facilitate species recognition and underlie the evolution of behavioral isolation.

Chronic Obstructive Pulmonary Disease and Cigarette Smoke Lead to Dysregulated Mucosal-associated Invariant T-Cell Activation.

Chronic obstructive pulmonary disease (COPD) is associated with airway inflammation, increased infiltration by CD8+ T lymphocytes, and infection-driven exacerbations. Although cigarette smoke is the leading risk factor for COPD, the mechanisms driving the development of COPD in only a subset of smokers are incompletely understood. Lung-resident mucosal-associated invariant T (MAIT) cells play a role in microbial infections and inflammatory diseases. The role of MAIT cells in COPD pathology is unknown. Here, we examined MAIT cell activation in response to cigarette smoke-exposed primary human bronchial epithelial cells (BECs) from healthy, COPD, or smoker donors. We observed significantly higher baseline MAIT cell responses to COPD BECs than healthy BECs. However, infected COPD BECs stimulated a smaller fold increase in MAIT cell response despite increased microbial infection. For all donor groups, cigarette smoke-exposed BECs elicited reduced MAIT cell responses; conversely, cigarette smoke exposure increased ligand-mediated MR1 surface translocation in healthy and COPD BECs. Our data demonstrate that MAIT cell activation is dysregulated in the context of cigarette smoke and COPD. MAIT cells could contribute to cigarette smoke- and COPD-associated inflammation through inappropriate activation and reduced early recognition of bacterial infection, contributing to microbial persistence and COPD exacerbations.

Ultra-rapid Electrophilic Cysteine Arylation.

Rapid bond-forming reactions are crucial for efficient bioconjugation. We describe a simple and practical strategy for facilitating ultra-rapid electrophilic cysteine arylation. Using a variety of sulfone-activated pyridinium salts, this uncatalyzed reaction proceeds with exceptionally high rate constants, ranging from 9800 to 320,000 M-1·s-1, in pH 7.0 aqueous buffer at 25 °C. Such reactions allow for stoichiometric bioconjugation of micromolar cysteine within minutes or even seconds. Even though the arylation is extremely fast, the chemistry exhibits excellent selectivity, thus furnishing functionalized peptides and proteins with both high conversion and purity.