Selenoprotein I is indispensable for ether lipid homeostasis and proper myelination.

Selenoprotein I (SELENOI) catalyzes the final reaction of the CDP-ethanolamine branch of the Kennedy pathway, generating the phospholipids phosphatidylethanolamine (PE) and plasmenyl-PE. Plasmenyl-PE is a key component of myelin and is characterized by a vinyl ether bond that preferentially reacts with oxidants, thus serves as a sacrificial antioxidant. In humans, multiple loss-of-function mutations in genes affecting plasmenyl-PE metabolism have been implicated in hereditary spastic paraplegia, including SELENOI. Herein, we developed a mouse model of nervous system-restricted SELENOI deficiency that circumvents embryonic lethality caused by constitutive deletion and recapitulates phenotypic features of hereditary spastic paraplegia. Resulting mice exhibited pronounced alterations in brain lipid composition, which coincided with motor deficits and neuropathology including hypomyelination, elevated reactive gliosis, and microcephaly. Further studies revealed increased lipid peroxidation in oligodendrocyte lineage cells and disrupted oligodendrocyte maturation both in vivo and in vitro. Altogether, these findings detail a critical role for SELENOI-derived plasmenyl-PE in myelination that is of paramount importance for neurodevelopment.

Deciphering the Role of Selenoprotein M.

Selenocysteine (Sec), the 21st amino acid, is structurally similar to cysteine but with a sulfur to selenium replacement. This single change retains many of the chemical properties of cysteine but often with enhanced catalytic and redox activity. Incorporation of Sec into proteins is unique, requiring additional translation factors and multiple steps to insert Sec at stop (UGA) codons. These Sec-containing proteins (selenoproteins) are found in all three domains of life where they often are involved in cellular homeostasis (e.g., reducing reactive oxygen species). The essential role of selenoproteins in humans requires us to maintain appropriate levels of selenium, the precursor for Sec, in our diet. Too much selenium is also problematic due to its toxic effects. Deciphering the role of Sec in selenoproteins is challenging for many reasons, one of which is due to their complicated biosynthesis pathway. However, clever strategies are surfacing to overcome this and facilitate production of selenoproteins. Here, we focus on one of the 25 human selenoproteins, selenoprotein M (SELENOM), which has wide-spread expression throughout our tissues. Its thioredoxin motif suggests oxidoreductase function; however, its mechanism and functional role(s) are still being uncovered. Furthermore, the connection of both high and low expression levels of SELENOM to separate diseases emphasizes the medical application for studying the role of Sec in this protein. In this review, we aim to decipher the role of SELENOM through detailing and connecting current evidence. With multiple proposed functions in diverse tissues, continued research is still necessary to fully unveil the role of SELENOM.

Dual incorporation of non-canonical amino acids enables production of post-translationally modified selenoproteins.

Post-translational modifications (PTMs) can occur on almost all amino acids in eukaryotes as a key mechanism for regulating protein function. The ability to study the role of these modifications in various biological processes requires techniques to modify proteins site-specifically. One strategy for this is genetic code expansion (GCE) in bacteria. The low frequency of post-translational modifications in bacteria makes it a preferred host to study whether the presence of a post-translational modification influences a protein's function. Genetic code expansion employs orthogonal translation systems engineered to incorporate a modified amino acid at a designated protein position. Selenoproteins, proteins containing selenocysteine, are also known to be post-translationally modified. Selenoproteins have essential roles in oxidative stress, immune response, cell maintenance, and skeletal muscle regeneration. Their complicated biosynthesis mechanism has been a hurdle in our understanding of selenoprotein functions. As technologies for selenocysteine insertion have recently improved, we wanted to create a genetic system that would allow the study of post-translational modifications in selenoproteins. By combining genetic code expansion techniques and selenocysteine insertion technologies, we were able to recode stop codons for insertion of N ε-acetyl-l-lysine and selenocysteine, respectively, into multiple proteins. The specificity of these amino acids for their assigned position and the simplicity of reverting the modified amino acid via mutagenesis of the codon sequence demonstrates the capacity of this method to study selenoproteins and the role of their post-translational modifications. Moreover, the evidence that Sec insertion technology can be combined with genetic code expansion tools further expands the chemical biology applications.

Selenoprotein I (selenoi) as a critical enzyme in the central nervous system.

Selenoprotein I (selenoi) is a unique selenocysteine (Sec)-containing protein widely expressed throughout the body. Selenoi belongs to two different protein families: the selenoproteins that are characterized by a redox reactive Sec residue and the lipid phosphotransferases that contain the highly conserved cytidine diphosphate (CDP)-alcohol phosphotransferase motif. Selenoi catalyzes the third reaction of the CDP-ethanolamine branch of the Kennedy pathway within the endoplasmic reticulum membrane. This is not a redox reaction and does not directly involve the Sec residue, making selenoi quite distinct among selenoproteins. Selenoi is also unique among lipid phosphotransferases as the only family member containing a Sec residue near its C-terminus that serves an unknown function. The reaction catalyzed by selenoi involves the transfer of the ethanolamine phosphate group from CDP-ethanolamine to one of two lipid donors, 1,2-diacylglycerol (DAG) or 1-alkyl-2-acylglycerol (AAG), to produce PE or plasmanyl PE, respectively. Plasmanyl PE is subsequently converted to plasmenyl PE by plasmanylethanolamine desaturase. Both PE and plasmenyl PE are critical phospholipids in the central nervous system (CNS), as demonstrated through clinical studies involving SELENOI mutations as well as studies in cell lines and mice. Deletion of SELENOI in mice is embryonic lethal, while loss-of-function mutations in the human SELENOI gene have been found in rare cases leading to a form of hereditary spastic paraplegia (HSP). HSP is an upper motor disease characterized by spasticity of the lower limbs, which is often manifested with other symptoms such as impaired vision/hearing, ataxia, cognitive/intellectual impairment, and seizures. This article will summarize the current understanding of selenoi as a metabolic enzyme and discuss its role in the CNS physiology and pathophysiology.

Selenoprotein I deficiency in T cells promotes differentiation into tolerant phenotypes while decreasing Th17 pathology.

Selenoprotein I (SELENOI) is an ethanolamine phospholipid transferase contributing to cellular metabolism and the synthesis of glycosylphosphatidylinositol (GPI) anchors. SELENOI knockout (KO) in T cells has been shown to impair metabolic reprogramming during T cell activation and reduce GPI-anchored Thy-1 levels, which are both crucial for Th17 differentiation. This suggests SELENOI may be important for Th17 differentiation, and we found that SELENOI was indeed up-regulated early during the activation of naïve CD4+ T cells in Th17 conditions. SELENOI KO reduced RORγt mRNA levels by decreasing SOX5 and STAT3 binding to promoter and enhancer regions in the RORC gene encoding this master regulator of Th17 cell differentiation. Differentiation of naïve CD4+ T cells into inflammatory versus tolerogenic Th cell subsets was analyzed and results showed that SELENOI deficiency skewed differentiation away from pathogenic Th17 cells (RORγt+ and IL-17A+ ) while promoting tolerogenic phenotypes (Foxp3+ and IL-10+ ). Wild-type and T cell-specific SELENOI KO mice were subjected to experimental autoimmune encephalitis (EAE), with KO mice exhibiting diminished clinical symptoms, reduced CNS pathology and decreased T cell infiltration. Flow cytometry showed that SELENOI T cell KO mice exhibited lower CD4+ RORγt+ and CD4+ IL-17A+ T cells and higher CD4+ CD25+ FoxP3+ T cells in CNS tissues of mice subjected to EAE. Thus, the metabolic enzyme SELENOI is up-regulated to promote RORγt transcription that drives Th17 differentiation, and SELENOI deficiency shifts differentiation toward tolerogenic phenotypes while protecting against pathogenic Th17 responses.

Functional signaling test identifies HER2 negative breast cancer patients who may benefit from c-Met and pan-HER combination therapy.

BACKGROUND: Research is revealing the complex coordination between cell signaling systems as they adapt to genetic and epigenetic changes. Tools to uncover these highly complex functional linkages will play an important role in advancing more efficacious disease treatments. Current tumor cell signal transduction research is identifying coordination between receptor types, receptor families, and transduction pathways to maintain tumor cell viability despite challenging tumor microenvironment conditions. METHODS: In this report, coactivated abnormal levels of signaling activity for c-Met and HER family receptors in live tumor cells were measured by a new clinical test to identify a subpopulation of breast cancer patients that could be responsive to combined targeted therapies. The CELsignia Multi-Pathway Signaling Function (CELsignia) Test uses an impedance biosensor to quantify an individual patient's ex vivo live tumor cell signaling response in real-time to specific HER family and c-Met co-stimulation and targeted therapies. RESULTS: The test identified breast tumors with hyperactive HER1, HER2, HER3/4, and c-Met coordinated signaling that express otherwise normal amounts of these receptors. The supporting data of the pre-clinical verification of this test included analyses of 79 breast cancer patients' cell response to HER and c-Met agonists. The signaling results were confirmed using clinically approved matching targeted drugs, and combinations of targeted drugs in addition to correlative mouse xenograft tumor response to HER and c-Met targeted therapies. CONCLUSIONS: The results of this study demonstrated the potential benefit of a functional test for identifying a subpopulation of breast cancer patients with coordinated abnormal HER and c-Met signaling for a clinical trial testing combination targeted therapy. Video Abstract.

T-cell activation decreases miRNA-15a/16 levels to promote MEK1-ERK1/2-Elk1 signaling and proliferative capacity.

While miRs have been extensively studied in the context of malignancy and tumor progression, their functions in regulating T-cell activation are less clear. In initial studies, we found reduced levels of miR-15a/16 at 3 to 18 h post-T-cell receptor (TCR) stimulation, suggesting a role for decreased levels of this miR pair in shaping T-cell activation. To further explore this, we developed an inducible miR15a/16 transgenic mouse model to determine how elevating miR-15a/16 levels during early stages of activation would affect T-cell proliferation and to identify TCR signaling pathways regulated by this miR pair. Doxycycline (DOX)-induced expression of miR-15a/16 from 0 to 18 h post-TCR stimulation decreased ex vivo T-cell proliferation as well as in vivo antigen-specific T-cell proliferation. We also combined bioinformatics and proteomics approaches to identify the mitogen-activated protein kinase kinase 1 (MEK1) (Map2k1) as a target of miR-15a/16. MEK1 targeting by miR-15a/16 was confirmed using miR mimics that decreased Map2k1 mRNA containing the 3'-UTR target nucleotide sequence (UGCUGCUA) but did not decrease Map2k1 containing a mutated control sequence (AAAAAAAA). Phosphorylation of downstream signaling molecules, extracellular signal-regulated protein kinase 1/2 (ERK1/2) and Elk1, was also decreased by DOX-induced miR-15a/16 expression. In addition to MEK1, ERK1 was subsequently found to be targeted by miR-15a/16, with DOX-induced miR-15a/16 reducing total ERK1 levels in T cells. These findings show that TCR stimulation reduces miR-15a/16 levels at early stages of T-cell activation to facilitate increased MEK1 and ERK1, which promotes the sustained MEK1-ERK1/2-Elk1 signaling required for optimal proliferation.

Three-Dimensional Printed Targeting Device for Scaphoid Fracture Fixation.

Background: Percutaneous guide wire insertion for scaphoid screw fixation can be challenging and often requires multiple attempts with significant radiation exposure to the surgical team. A 3-dimensional (3D) printed targeting device has the potential to reduce procedure time and intraoperative radiation exposure. Methods: Our targeting device protocol included a preprocedure computed tomography (CT) scan of a casted cadaver wrist, followed by 3D printing of a customized targeting guide. In a comparison trial, seven orthopedic surgery residents performed percutaneous scaphoid guide wire insertion on different cadaver specimens by both freehand technique and using our targeting device. Radiation exposure and procedure times were compared. All specimens underwent postprocedure CT to assess Kirschner wire (K-wire) accuracy, determined by central third placement. Pre- and postprocedure CT scans from the targeting device group were co-registered to compare planned and actual K-wire trajectories. Results: Using the freehand technique, mean fluoroscopy time was 120 seconds (standard deviation: ±53 seconds) generating 2.45 milligray of radiation. Average procedure time was 21 minutes with a mean of 6.4 (range: 3-9) insertion attempts. A single insertion attempt was made using the targeting device with an average procedure time of 30 seconds and no fluoroscopy exposure. Four K-wires were placed within the central scaphoid in both groups. Using the targeting device, average linear deviation from the planned trajectory was 2.1 mm, while the maximum linear deviation was 3.75 mm. Conclusion: When compared to freehand scaphoid guide wire insertion, our targeting device provides similar accuracy while significantly reducing intraoperative radiation exposure and procedure time.

Ultrasound diagnosis of pyogenic flexor tenosynovitis in a 9-month-old infant: a rare case report.

Pyogenic flexor tenosynovitis (PFT) is an aggressive infection of the flexor tendon sheath, requiring prompt intervention to minimize adverse outcomes. The diagnosis of pediatric PFT is often delayed due to the variable presence of Kanavel's signs in children and communication difficulties. A 9-month-old male presented to the emergency department with one of four Kanavel signs. The diagnosis of PFT was delayed until ultrasound was used to identify a fluid collection within the flexor tendon sheath. He was successfully treated with surgical debridement and antibiotic therapy, achieving full recovery by 6-month follow-up. This represents the youngest reported case of PFT. Difficulties with communication and physical exam as well as the variability of Kanavel's signs in young children can delay the diagnosis of pediatric PFT. Ultrasound can be a useful adjunct when clinical history and exam are equivocal, especially in children who present prior to language acquisition.

An example of DNA methylation as a means to quantify stress in wildlife using killer whales.

The cumulative effects of non-lethal stressors on the health of biodiversity are a primary concern for conservation, yet difficulties remain regarding their quantification. In mammals, many stressors are processed through a common stress-response pathway, and therefore epigenetic changes in genes of this pathway may provide a powerful tool for quantifying cumulative effects. As a preliminary assessment of this approach, we investigated epigenetic manifestations of stress in two killer whale populations with different levels of exposure to anthropogenic stressors. We used bisulfite amplicon sequencing to compare patterns of DNA methylation at 25 CpG sites found in three genes involved in stress response and identified large differences in the level of methylation at two sites consistent with differential stress exposure between Northern and Southern Resident killer whale populations. DNA methylation patterns could therefore represent a useful method to assess the cumulative effects of non-lethal stressors in wildlife.

Self-Inflicted Hand Amputation without Replantation in a Patient with Body Integrity Identity Disorder: A Case Report.

CASE: We describe a patient who self-amputated his hand using a log splitter, because of a long-standing belief that the limb "did not belong to him." On admission, he refused replantation and was found to be nonpsychotic. He was diagnosed with body integrity identity disorder (BIID) and declared competent to make his own medical decisions. A revision amputation was performed. CONCLUSION: BIID is a challenging diagnosis that physicians treating traumatic injuries should be aware of. Many ethicists support elective amputation as a definitive treatment, because of potential harm reduction and because BIID does not respond to conservative modalities such as pharmacotherapy.

Effects of foam rolling for delayed onset muscle soreness on loaded military task performance and perceived recovery.

OBJECTIVE: The purpose of this investigation was to evaluate the effects of foam rolling (FR) and passive recovery (PR) on symptoms of delayed-onset muscle soreness (DOMS) and military-specific performance. METHODS: Twenty men and women (age: 23.6 ± 4.1 years, height: 176.4 ± 5.6 cm, and body mass: 84.7 ± 13.4 kg) completed a DOMS-inducing exercise protocol (DIP), followed by FR or PR. Four loaded military tasks (LMT) were performed 24 h later. Rating of perceived exertion (RPE) was measured during DIP and after each LMT. Rating of muscle pain (RMP) was measured prior to the LMTs and after the recovery protocols. A repeated measure analysis of variance and partial eta squared were used to compare LMT performance across baseline, FR and PR sessions. Friedman tests compared perceptual variables across baseline, FR, and PR. Wilcoxon matched-pairs signed-ranks test evaluated RPE during DIP, post-DIP, and post-recovery RMP between FR and PR. RESULTS: LMT performance times were significantly faster after FR compared to PR (stair climb: p = .038, cover position sprint: p = .011, simulated ammunition can carry: p = .003, Shuttle Run: p = .034). RPE measured during LMTs was similar across all data points. Post-recovery RMP for FR (3.0 (2.3, 4.0)) and PR (4.0 (3.0, 6.0)) were not significantly different. CONCLUSION: FR reduced the impact of DOMS on three loaded tactical performance tasks without significant reduction in perceived soreness.

Population structure in a continuously distributed coastal marine species, the harbor porpoise, based on microhaplotypes derived from poor-quality samples.

Harbor porpoise in the North Pacific are found in coastal waters from southern California to Japan, but population structure is poorly known outside of a few local areas. We used multiplexed amplicon sequencing of 292 loci and genotyped clusters of single nucleotide polymoirphisms as microhaplotypes (N = 271 samples) in addition to mitochondrial (mtDNA) sequence data (N = 413 samples) to examine the genetic structure from samples collected along the Pacific coast and inland waterways from California to southern British Columbia. We confirmed an overall pattern of strong isolation-by-distance, suggesting that individual dispersal is restricted. We also found evidence of regions where genetic differences are larger than expected based on geographical distance alone, implying current or historical barriers to gene flow. In particular, the southernmost population in California is genetically distinct (FST  = 0.02 [microhaplotypes]; 0.31 [mtDNA]), with both reduced genetic variability and high frequency of an otherwise rare mtDNA haplotype. At the northern end of our study range, we found significant genetic differentiation of samples from the Strait of Georgia, previously identified as a potential biogeographical boundary or secondary contact zone between harbor porpoise populations. Association of microhaplotypes with remotely sensed environmental variables indicated potential local adaptation, especially at the southern end of the species' range. These results inform conservation and management for this nearshore species, illustrate the value of genomic methods for detecting patterns of genetic structure within a continuously distributed marine species, and highlight the power of microhaplotype genotyping for detecting genetic structure in harbor porpoises despite reliance on poor-quality samples.

A Comparative Analysis of Army Body Composition Standards for Women.

The aim of this study was to compare body fat percentage (BF%) of women measured using the U.S. Army standard body composition assessment (ABC) and two common laboratory measures of body composition to evaluate the efficacy of ABC within this population. The BF% of 27 women (21.5 ± 1.8 years) was assessed using the 7-site skinfold, air plethysmography, and ABC measurements. The initial physical fitness test (IPFT) was used to determine if participants met the criteria required for admittance into basic combat training. A repeated measures ANOVA identified differences in BF% between the three assessment methods, (F (2, 52) = 22.83, p < .001, η2 p = .47). Pairwise comparisons revealed that mean BF% obtained using the ABC (29.3 ± 7.7 %) was significantly higher (p = .042) than BF% measured using air plethysmography (26.9 ± 8.4 %). ABC and air plethysmography measured BF% was significantly higher (both p < .001) than BF% obtained from skinfold assessment (22.2 ± 5.9 %). Of the 27 total participants, 4 (14.8%) passed IPFT but failed to meet the Army body composition standards using the ABC method. The primary findings of this study suggest that the overestimation of BF% by the ABC method could lead to an unnecessary delay in enlistment for women approaching the upper threshold of the Army's acceptable body composition standards. Alternative methods of assessing body composition in this population should be explored. However, skinfold assessment does not appear to be a suitable alternative to the ABC.

New HER2-negative breast cancer subtype responsive to anti-HER2 therapy identified.

PURPOSE: HER2 signaling functional activity may be important to measure in addition to HER2 protein quantification when identifying patients eligible for HER2 therapies. A HER2 Signaling Function (CELx HSF) Test for HER2-negative patients uses patient's live tumor cells on a biosensor to identify patients with abnormally high HER2-related signaling (HSFs+) likely to respond to anti-HER2 therapies. METHODS: The CELx HSF test was employed to: (1) characterize the sensitivity and specificity of the test to detect abnormal levels of HER2 signaling; (2) evaluate the inhibitory effectiveness of five different anti-HER2 therapies; (3) assess the correlation between CELx HSF test detection of abnormal HER2 signaling and response to HER2 therapy using xenograft models; and (4) confirm the prevalence of abnormal HER2 signaling amongst HER2-negative breast cancer patients (HER2-/HSFs+). RESULTS: HER2-/HSFs+ breast cancer patient samples were identified and showed sensitivity to five approved anti-HER2 therapies. Xenograft studies using both HER2+ and HER2- cell lines confirmed that CELx HER2 signaling status better predicts HER2 inhibitor efficacy than HER2 receptor status. In a study of 114 HER2-negative breast tumor patient samples, 27 (23.7%; 95% CI = 17-32%) had abnormal HER2 signaling (HSFs+). A ROC curve constructed with this dataset projects the CELx HSF Test would have greater than 90% sensitivity and specificity to detect the HER2-/HSFs+ patient population. CONCLUSIONS: The CELx HSF test is a well-characterized functional biomarker assay capable of identifying dynamic HER2-driven signaling dysfunction in tumor cells from HER2-negative breast cancer patients. This test has demonstrated efficacy of various HER2 targeted therapies in live tumor cells from the HSFs+ population and correlated the test result to HER2 drug response in mouse xenograft studies. The proportion of HER2-negative breast cancer patients found to have abnormal HER2 signaling in a 114 patient sample study, 20-25%, is significant. A clinical trial to evaluate the efficacy of anti-HER2 therapies in this patient population is warranted.

Assessing Femoral Rotation: A Survey Comparison of Techniques.

OBJECTIVES: To compare 3 common techniques for assessing femoral malrotation through a response analysis. METHODS: Ten intact human cadaveric pelvis-to-knee specimens were used to create a fracture model. A mobile C-arm x-ray system was used to capture images of an intact control femur and a contralateral test femur on each specimen. A midshaft femoral osteotomy was created on the test femur and it was then internally and externally rotated in 5-degree intervals up to 20 degrees. Images were obtained and stored at each increment of malrotation. Eight surveys of 20-paired images each were generated and presented for surgeon review. Accuracy of predicting femoral malrotation using the true lateral technique (TLT), neck horizontal angle (NHA) method, and lesser trochanter profile (LTP) was measured. RESULTS: Eighty-five surgeons completed a survey with 80 surgeons (94%) acknowledging the use of a described fluoroscopic method for assisting with rotational alignment. Surgeons correctly accepted a fracture rotated less than 20 degrees and rejected a fracture rotated 20 degrees or more 63% of the time. The ability to correctly identify 20 degrees of malrotation varied per technique used to assess rotation. With the LTP and NHA method, 67% of surgeons responded correctly. Surgeons performed significantly worse when using the TLT with only 53% providing correct responses (P < 0.0001). CONCLUSIONS: Surgeons using described fluoroscopic methods to identify acceptable rotation in femoral shaft fractures are correct 63% of the time. The LTP and NHA techniques are equally reliable and more effective than the TLT at detecting clinically significant femoral malrotation.

Parents' Perceptions and Use of School-Based Body Mass Index Report Cards.

BACKGROUND: Obesity in children and adolescents has become one of the most critical public health problems in the United States. Schools may play an important role in raising awareness and possibly slowing the obesity epidemic. METHODS: The purpose of this study was to gather information on parents' perception and use of body mass index (BMI) report cards provided by public schools through the administration of a questionnaire. The questionnaire was developed with the assistance of physical educators, pediatricians, and exercise scientists. The questionnaires were backpacked home with 1127 students in 6 Arkansas public schools. Parents completed and returned 404 questionnaires. RESULTS: Findings indicate that parents are supportive of schools reporting BMI and providing information on healthier lifestyles. However, most parents reported not making any adjustment to their child's diet and physical activity habits based on the BMI reports. Approximately half of parents (55%) thought the BMI report accurately reflected their child's health status. Approximately half of the parents reported their child's BMI report led them to think about their family's health habits. CONCLUSIONS: Although parents do support receiving BMI information from schools, many did not indicate using the data to initiate changes such as increased physical activity or healthy eating.

Click reception in the harbor porpoise (Phocoena phocoena): Effects of electrode and contact transducer location on the auditory brainstem response.

Unlike terrestrial mammals that have unambiguous aerial sound transmission pathways via the outer ear and tympanum, sound reception pathways in most odontocetes are not well understood. Recent studies have used auditory brainstem response (ABR) measurements to examine sound reception pathways. This study sought to determine how sound source placements, recording electrode arrangements, and ABR peak analyses affect interpretations of sound reception in the harbor porpoise (Phocoena phocoena). Click stimuli were delivered in air from a contact transducer ("jawphone"). Early ABR peaks (representing auditory nerve responses), and later peaks reflecting higher brainstem activity, were analyzed across jawphone and recording electrode positions. Auditory nerve responses were similar for jawphone placements from the ipsilateral posterior mandible to the tip of the rostrum. Later peaks, however, suggested a possible region of highest sensitivity midway between the posterior mandible and the rostrum tip. These findings are generally similar to previous data for porpoises. In contrast to auditory nerve responses that were largest when recorded near the ipsilateral meatus, later ABR peaks were largest when recorded with a contralateral (opposing) electrode. These results provide information on the processes underlying peaks of the ABR, and inform stimulus delivery and ABR recording parameters in odontocete sound reception studies.

Extensive Core Microbiome in Drone-Captured Whale Blow Supports a Framework for Health Monitoring.

The pulmonary system is a common site for bacterial infections in cetaceans, but very little is known about their respiratory microbiome. We used a small, unmanned hexacopter to collect exhaled breath condensate (blow) from two geographically distinct populations of apparently healthy humpback whales (Megaptera novaeangliae), sampled in the Massachusetts coastal waters off Cape Cod (n = 17) and coastal waters around Vancouver Island (n = 9). Bacterial and archaeal small-subunit rRNA genes were amplified and sequenced from blow samples, including many of sparse volume, as well as seawater and other controls, to characterize the associated microbial community. The blow microbiomes were distinct from the seawater microbiomes and included 25 phylogenetically diverse bacteria common to all sampled whales. This core assemblage comprised on average 36% of the microbiome, making it one of the more consistent animal microbiomes studied to date. The closest phylogenetic relatives of 20 of these core microbes were previously detected in marine mammals, suggesting that this core microbiome assemblage is specialized for marine mammals and may indicate a healthy, noninfected pulmonary system. Pathogen screening was conducted on the microbiomes at the genus level, which showed that all blow and few seawater microbiomes contained relatives of bacterial pathogens; no known cetacean respiratory pathogens were detected in the blow. Overall, the discovery of a shared large core microbiome in humpback whales is an important advancement for health and disease monitoring of this species and of other large whales. IMPORTANCE The conservation and management of large whales rely in part upon health monitoring of individuals and populations, and methods generally necessitate invasive sampling. Here, we used a small, unmanned hexacopter drone to noninvasively fly above humpback whales from two populations, capture their exhaled breath (blow), and examine the associated microbiome. In the first extensive examination of the large-whale blow microbiome, we present surprising results about the discovery of a large core microbiome that was shared across individual whales from geographically separated populations in two ocean basins. We suggest that this core microbiome, in addition to other microbiome characteristics, could be a useful feature for health monitoring of large whales worldwide.