Addressing the challenges of monitoring a rare and elusive seabird

The Kittlitz’s murrelet (Brachyramphus brevirostris) is a small alcid endemic to Alaska and eastern Russia. Due to its pelagic lifestyle, researchers lack information regarding environmental conditions experienced by Kittlitz’s murrelets throughout the year and how these conditions impact their physiology and vital rates. Further, unlike most seabirds, the Kittlitz’s murrelet is a dispersed nester; therefore, data are limited for this species even within the breeding season. The goal of this research was to evaluate and improve the monitoring methods for the Kittlitz’s murrelet throughout the year. I approached this goal from 2 different perspectives. First, I worked to clarify abundance and trend estimates that have been questioned due to uncertainty in species identification. Second, I used physiological measures to examine the relationships between stress, parental investment, breeding propensity, and environmental conditions experienced by Kittlitz’s murrelets throughout the year. To address uncertainties in species identification, I conducted a field experiment to quantify misidentification and non-identification rates of Brachyramphus murrelets during abundance surveys and evaluate the impacts of covariates on each. I found that misidentification of species was rare and did not bias abundance estimates. Additionally, non-identification was common beyond observation distances of 140 m, though this depended on observer experience, murrelet behavior, and sea conditions. To understand the environmental conditions experienced by Kittlitz’s murrelets throughout the year, I measured corticosterone (avian stress hormone) and prolactin (parental expression hormone) and evaluated their relationships with breeding propensity and ocean productivity metrics. Higher levels of stress during the pre-and post-breeding seasons reflected lower rates of breeding propensity in the following season. Additionally, higher stress was associated with lower sea surface temperatures during the pre-breeding season, and earlier capture dates, longer time-spans between capture and processing, and lower body mass during the late-breeding season. Prolactin positively reflected CORT during the early breeding season and sex during the late breeding season. These results emphasize the need for continued research to understand the mechanisms linking the stress physiology, foraging ecology, and breeding ecology of the Kittlitz’s murrelet and other species that depend on similar resources

Testing factors influencing identification rates of similar species during abundance surveys

Most abundance estimation methods assume that all sampled individuals are identified correctly. In practice, this assumption may be difficult to meet and can bias abundance estimates, especially when morphologically similar species overlap in range. Over the past 2 decades, Kittlitz\u27s Murrelet (Brachyramphus brevirostris) populations appear to have declined across parts of their Alaskan range, where they co-occur with the Marbled Murrelet (B. marmoratus). Recently, the reliability of Kittlitz\u27s Murrelet declines have been questioned due to variability and uncertainty in species identification between the 2 species. We conduced a field experiment to quantify misidentification and partial identification (identification to genus [Brachyramphus] level only) of Kittlitz\u27s and Marbled murrelets during abundance surveys, and to evaluate the relative impacts of environmental and observational factors on misidentification and partial identification. We applied these results to previously collected survey data to measure the potential bias of abundance estimates resulting from varying identification rates. Overall, the misidentification rate during our field experiment was -0.036 + 0.004 (SE), with observer experience best explaining the variation. Abundance estimates adjusted for misidentification reflected little bias. The overall partial identification rate was much higher than the misidentification rate (0.211 + 0.007 SE). Partial identification rates increased in choppy sea states, with greater observation distances, and when murrelets exhibited diving behavior; rates decreased with increased observer experience and when murrelets exhibited flushing behavior. Because observer experience was an important driver of both misidentification and partial identification, we stress the importance of conducting rigorous observer training before and during surveys to increase confidence in species identification and precision in abundance estimates. the methods developed in this study could be modified for any at-sea survey scenario to measure identification rates and the factors influencing these rates. Results may reveal important relationships for adjusting survey protocolors to increase confidence in species identification and thereby to increase the precision of abundance estimates

Surrogate Light Chain Expressing Human Peripheral B Cells Produce Self-reactive Antibodies

Human B cells that coexpress surrogate and conventional light chains (V-preB+L+) show an unusual heavy and light chain antibody repertoire that display evidence of receptor editing. However, it is unclear whether V-preB+L+ B cells have been silenced by receptor editing or still express autoreactive antibodies. Here we report that 68% of the antibodies expressed by V-preB+L+ B cells are autoreactive. A majority of these autoantibodies are true antinuclear antibodies (ANA), and 50% of the ANAs are also reactive with a diverse group of antigens that include dsDNA, ssDNA, immunoglobulin, insulin, and bacterial lipopolysaccharide. Such antibodies are rarely encountered among conventional B cells. We conclude that V-preB+L+ B cells are a unique subset of normal circulating human B cells that escape central tolerance mechanisms and express self-reactive antibodies including potentially harmful ANAs

Sample Preparation and Warping Accuracy for Correlative Multimodal Imaging in the Mouse Olfactory Bulb Using 2-Photon, Synchrotron X-Ray and Volume Electron Microscopy

Integrating physiology with structural insights of the same neuronal circuit provides a unique approach to understanding how the mammalian brain computes information. However, combining the techniques that provide both streams of data represents an experimental challenge. When studying glomerular column circuits in the mouse olfactory bulb, this approach involves e.g., recording the neuronal activity with in vivo 2-photon (2P) calcium imaging, retrieving the circuit structure with synchrotron X-ray computed tomography with propagation-based phase contrast (SXRT) and/or serial block-face scanning electron microscopy (SBEM) and correlating these datasets. Sample preparation and dataset correlation are two key bottlenecks in this correlative workflow. Here, we first quantify the occurrence of different artefacts when staining tissue slices with heavy metals to generate X-ray or electron contrast. We report improvements in the staining procedure, ultimately achieving perfect staining in ∼67% of the 0.6 mm thick olfactory bulb slices that were previously imaged in vivo with 2P. Secondly, we characterise the accuracy of the spatial correlation between functional and structural datasets. We demonstrate that direct, single-cell precise correlation between in vivo 2P and SXRT tissue volumes is possible and as reliable as correlating between 2P and SBEM. Altogether, these results pave the way for experiments that require retrieving physiology, circuit structure and synaptic signatures in targeted regions. These correlative function-structure studies will bring a more complete understanding of mammalian olfactory processing across spatial scales and time

Heterochromatin-Mediated Gene Silencing Facilitates the Diversification of Olfactory Neurons

An astounding property of the nervous system is its cellular diversity. This diversity, which was initially realized by morphological and electrophysiological differences, is ultimately produced by variations in gene-expression programs. In most cases, these variations are determined by external cues. However, a growing number of neuronal types have been identified in which inductive signals cannot explain the few but decisive transcriptional differences that cause cell diversification. Here, we show that heterochromatic silencing, which we find is governed by histone methyltransferases G9a (KMT1C) and GLP (KMT1D), is essential for stochastic and singular olfactory receptor (OR) expression. Deletion of G9a and GLP dramatically reduces the complexity of the OR transcriptome, resulting in transcriptional domination by a few ORs and loss of singularity in OR expression. Thus, our data suggest that, in addition to its previously known functions, heterochromatin creates an epigenetic platform that affords stochastic, mutually exclusive gene choices and promotes cellular diversity

Defining quality physical education: an analysis of international documents

Abstract presented at the 2014 AAHPERD National Convention and Exposition, 2-4 April 2014, St. Louis, United State