Glia-derived secretory fatty acid binding protein Obp44a regulates lipid storage and efflux in the developing Drosophila brain.

Glia derived secretory factors play diverse roles in supporting the development, physiology, and stress responses of the central nervous system (CNS). Through transcriptomics and imaging analyses, we have identified Obp44a as one of the most abundantly produced secretory proteins from Drosophila CNS glia. Protein structure homology modeling and Nuclear Magnetic Resonance (NMR) experiments reveal Obp44a as a fatty acid binding protein (FABP) with a high affinity towards long-chain fatty acids in both native and oxidized forms. Further analyses demonstrate that Obp44a effectively infiltrates the neuropil, traffics between neuron and glia, and is secreted into hemolymph, acting as a lipid chaperone and scavenger to regulate lipid and redox homeostasis in the developing brain. In agreement with this essential role, deficiency of Obp44a leads to anatomical and behavioral deficits in adult animals and elevated oxidized lipid levels. Collectively, our findings unveil the crucial involvement of a noncanonical lipid chaperone to shuttle fatty acids within and outside the brain, as needed to maintain a healthy brain lipid environment. These findings could inspire the design of novel approaches to restore lipid homeostasis that is dysregulated in CNS diseases.

Brain-specific lipoprotein receptors interact with astrocyte derived apolipoprotein and mediate neuron-glia lipid shuttling.

Lipid shuttling between neurons and glia contributes to the development, function, and stress responses of the nervous system. To understand how a neuron acquires its lipid supply from specific lipoproteins and their receptors, we perform combined genetic, transcriptome, and biochemical analyses in the developing Drosophila larval brain. Here we report, the astrocyte-derived secreted lipocalin Glial Lazarillo (GLaz), a homolog of human Apolipoprotein D (APOD), and its neuronal receptor, the brain-specific short isoforms of Drosophila lipophorin receptor 1 (LpR1-short), cooperatively mediate neuron-glia lipid shuttling and support dendrite morphogenesis. The isoform specificity of LpR1 defines its distribution, binding partners, and ability to support proper dendrite growth and synaptic connectivity. By demonstrating physical and functional interactions between GLaz/APOD and LpR1, we elucidate molecular pathways mediating lipid trafficking in the fly brain, and provide in vivo evidence indicating isoform-specific expression of lipoprotein receptors as a key mechanism for regulating cell-type specific lipid recruitment.

Using cameras to index waterfowl abundance in winter-flooded rice fields.

Extensive wetland habitat loss across the continental United States has caused post-harvested rice fields to become an important surrogate wetland habitat for migratory waterfowl. Flooded rice fields used by waterfowl have the potential to provide agronomic benefits to soil. Increasing interest in the reciprocal relationship between birds and flooded rice fields has given rise to many studies that aim to quantify bird abundance. However, surveying large flocks of birds in open agricultural fields is challenging because traditional ground and aerial surveys can cause birds to flush or re-allocate spatially, thus biasing counts that are reflected in following management practice recommendations. To avoid this, we used camera surveys and an open-access image manipulation program to estimate 24-h bird use of rice fields. Indices of bird abundance from counts were used to estimate fecal matter input to rice fields. Camera surveys have the potential to limit biases seen in other methods because of their ability to capture bird use over a 24-h period over an entire season and the ability for multiple researchers to survey the same site.•Surveying bird flocks by traditional ground or aerial surveys can bias bird abundance estimates.•Camera surveys of waterfowl in rice fields were used to estimate bird abundance and fecal matter input.•Camera surveys reflect static bird use over 24-h which can lower bias seen in traditional methods.

Robust CRISPR/Cas9-Mediated Tissue-Specific Mutagenesis Reveals Gene Redundancy and Perdurance in Drosophila.

Tissue-specific loss-of-function (LOF) analysis is essential for characterizing gene function. Here, we present a simple, yet highly efficient, clustered regularly interspaced short palindromic repeats (CRISPR)-mediated tissue-restricted mutagenesis (CRISPR-TRiM) method for ablating gene function in Drosophila This binary system consists of a tissue-specific Cas9 and a ubiquitously expressed multi-guide RNA (gRNA) transgene. We describe convenient toolkits for making enhancer-driven Cas9 lines and multi-gRNAs that are optimized for mutagenizing somatic cells. We demonstrate that insertions or deletions in coding sequences more reliably cause somatic mutations than DNA excisions induced by two gRNAs. We further show that enhancer-driven Cas9 is less cytotoxic yet results in more complete LOF than Gal4-driven Cas9 in larval sensory neurons. Finally, CRISPR-TRiM efficiently unmasks redundant soluble N-ethylmaleimide-sensitive factor attachment protein receptor gene functions in neurons and epidermal cells. Importantly, Cas9 transgenes expressed at different times in the neuronal lineage reveal the extent to which gene products persist in cells after tissue-specific gene knockout. These CRISPR tools can be applied to analyze tissue-specific gene function in many biological processes.

Transcriptional Regulation of Lipophorin Receptors Supports Neuronal Adaptation to Chronic Elevations of Activity.

Activity-dependent modifications strongly influence neural development. However, molecular programs underlying their context and circuit-specific effects are not well understood. To study global transcriptional changes associated with chronic elevation of synaptic activity, we performed cell-type-specific transcriptome profiling of Drosophila ventral lateral neurons (LNvs) in the developing visual circuit and identified activity-modified transcripts that are enriched in neuron morphogenesis, circadian regulation, and lipid metabolism and trafficking. Using bioinformatics and genetic analyses, we validated activity-induced isoform-specific upregulation of Drosophila lipophorin receptors LpR1 and LpR2, the homologs of mammalian low-density lipoprotein receptor (LDLR) family proteins. Furthermore, our morphological and physiological studies uncovered critical functions of neuronal lipophorin receptors (LpRs) in maintaining the structural and functional integrities in neurons challenged by chronic elevations of activity. Together, our findings identify LpRs as molecular targets for activity-dependent transcriptional regulation and reveal the functional significance of cell-type-specific regulation of neuronal lipid uptake in experience-dependent plasticity and adaptive responses.

Experience-dependent structural plasticity targets dynamic filopodia in regulating dendrite maturation and synaptogenesis.

Highly motile dendritic protrusions are hallmarks of developing neurons. These exploratory filopodia sample the environment and initiate contacts with potential synaptic partners. To understand the role for dynamic filopodia in dendrite morphogenesis and experience-dependent structural plasticity, we analyzed dendrite dynamics, synapse formation, and dendrite volume expansion in developing ventral lateral neurons (LNvs) of the Drosophila larval visual circuit. Our findings reveal the temporal coordination between heightened dendrite dynamics with synaptogenesis in LNvs and illustrate the strong influence imposed by sensory experience on the prevalence of dendritic filopodia, which regulate the formation of synapses and the expansion of dendritic arbors. Using genetic analyses, we further identified Amphiphysin (Amph), a BAR (Bin/Amphiphysin/Rvs) domain-containing protein as a required component for tuning the dynamic state of LNv dendrites and promoting dendrite maturation. Taken together, our study establishes dynamic filopodia as the key cellular target for experience-dependent regulation of dendrite development.

Inter-hospital transfers from rural hospitals to an academic medical center.

INTRODUCTION: The need for inter-hospital patient transfers from rural hospitals, especially Critical Access Hospitals, to larger, more urban hospitals is predictable considering the limited resources at rural hospitals. No systematic study of the inter-hospital transfers themselves has been published. The aim of this retrospective descriptive chart review was to provide a preliminary look at inter-hospital transfers from rural hospitals to a more urban, academic medical center in West Virginia. Ultimately, the creation of an agenda for further research was in view. METHODS: A list of study participants was generated from the academic center's electronic health record database. Study participants were patients who had been transferred for acute care, from November 2011 through June 2012, to the receiving hospital from another acute care hospital and had been under the care of the family medicine teaching service. RESULTS: One hundred and thirty-eight patient transfers were included. Medicare was the most common source of health insurance coverage but over a third of the patients were uninsured. Only five of the twenty-four referring hospitals were Critical Access Hospitals. Four institutions alone initiated 49.3% of transfers. Nineteen specialty services were sought with critical care and neurology accounting for 53.9% of requests. Stroke or stroke-like presentation was the most common transfer diagnosis. 24.6% of transfers were transferred for services that were available at the transferring facility. CONCLUSIONS: This study has suggested an agenda for further research that includes replication and analysis of the data with larger study samples as well as qualitative research into the transferring physicians' decision-making process.