321 research outputs found
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Drosophila astrocytes cover specific territories of the CNS neuropil and are instructed to differentiate by Prospero, a key effector of Notch.
Astrocytes are crucial in the formation, fine-tuning, function and plasticity of neural circuits in the central nervous system. However, important questions remain about the mechanisms instructing astrocyte cell fate. We have studied astrogenesis in the ventral nerve cord of Drosophila larvae, where astrocytes exhibit remarkable morphological and molecular similarities to those in mammals. We reveal the births of larval astrocytes from a multipotent glial lineage, their allocation to reproducible positions, and their deployment of ramified arbors to cover specific neuropil territories to form a stereotyped astroglial map. Finally, we unraveled a molecular pathway for astrocyte differentiation in which the Ets protein Pointed and the Notch signaling pathway are required for astrogenesis; however, only Notch is sufficient to direct non-astrocytic progenitors toward astrocytic fate. We found that Prospero is a key effector of Notch in this process. Our data identify an instructive astrogenic program that acts as a binary switch to distinguish astrocytes from other glial cells.This work was supported by grants from the Canadian Institutes of Health Research (CIHR) and the Canada Foundation for Innovation (CFI) to D.J.v.M.; by a Biotechnology and Biological Sciences Research Council (UK) grant [BB/I022414/1] to M.L.; and by studentship awards to S.D. from McGill University (Max Stern) and the Integrated Program in Neuroscience.This is the author accepted manuscript. The final version is available from the Company of Biologists via http://dx.doi.org/10.1242/dev.13316
Quantitative volumetric Raman imaging of three dimensional cell cultures
The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell–material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy
Gender Specific Effect of Psychological Stress and Cortisol Reactivity on Adolescent Risk Taking
The purpose of this study was to evaluate how psychological stress, gender and cortisol response to stress relate to risk behavior among 132 14–18 year old adolescents. Participants completed a laboratory based risk task prior to and immediately after a computerized psychological stress task, and salivary cortisol was collected from pre-stress to 60 minutes following initial stress exposure. Results indicate that adolescent boys (n = 59) and girls (n = 73) demonstrate different patterns of risk taking (RT) in response to stress, such that boys evidenced an increase in RT following stress exposure, whereas girls evidenced a decrease in RT. In addition, a gender by cortisol interaction demonstrated that for boys, both a smaller total cortisol output (AUCg) and peak cortisol response to stress (PC) was associated with greater stress-induced RT. Both cortisol measures were unrelated to stress-induced RT among girls. Taken together, data suggest that among boys, a blunted cortisol response to stress underlies an increase in risk taking in the context of psychological stress. Further research with an additional behavioral stress task is needed prior to drawing conclusions regarding the relation between female gender, cortisol response to stress, and risk taking in the context of psychological stress
In children, the microbiota of the nasopharynx and bronchoalveolar lavage fluid are both similar and different
RATIONALE:
Sputum and bronchoalveolar lavage fluid (BALF) are often obtained to elucidate the lower airway microbiota in adults. Acquiring sputum samples from children is difficult and obtaining samples via bronchoscopy in children proves challenging due to the need for anesthesia and specialized procedural expertise; therefore nasopharyngeal (NP) swabs are often used as surrogates when investigating the pediatric airway microbiota. In adults, the airway microbiota differs significantly between NP and BALF samples however, minimal data exist in children.
OBJECTIVES:
To compare NP and BALF samples in children undergoing clinically indicated bronchoscopy.
METHODS:
NP and BALF samples were collected during clinically indicated bronchoscopy. Bacterial DNA was extracted from 72 samples (36 NP/BALF pairs); the bacterial V1-V3 region of the 16S rRNA gene was amplified and sequenced on the Illumina Miseq platform. Analysis was performed using mothur software.
RESULTS:
Compared to NP samples, BALF had increased richness and diversity. Similarity between paired NP and BALF (intra-subject) samples was greater than inter-subject samples (P = 0.0006). NP samples contained more Actinobacteria (2.2% vs 21%; adjusted P = 1.4 × 10-6 ), while BALF contained more Bacteroidetes (29.5% vs 3.2%; adjusted P = 1.2 × 10-9 ). At the genus level several differences existed, however Streptococcus abundance was similar in both sample types (NP 37.3% vs BAL 36.1%; adjusted P = 0.8).
CONCLUSION:
Our results provide evidence that NP samples can be used to distinguish differences between children, but the relative abundance of organisms may differ between the nasopharynx and lower airway in pediatric patients. Studies utilizing NP samples as surrogates for the lower airway should be interpreted with caution
Nitric Oxide-Releasing Nanoparticles Prevent Propionibacterium acnes-Induced Inflammation by Both Clearing the Organism and Inhibiting Microbial Stimulation of the Innate Immune Response.
Propionibacterium acnes induction of IL-1 cytokines through the NLRP3 (NLR, nucleotide oligomerization domain-like receptor) inflammasome was recently highlighted as a dominant etiological factor for acne vulgaris. Therefore, therapeutics targeting both the stimulus and the cascade would be ideal. Nitric oxide (NO), a potent biological messenger, has documented broad-spectrum antimicrobial and immunomodulatory properties. To harness these characteristics to target acne, we used an established nanotechnology capable of generating/releasing NO over time (NO-np). P. acnes was found to be highly sensitive to all concentrations of NO-np tested, although human keratinocyte, monocyte, and embryonic zebra fish assays revealed no cytotoxicity. NO-np significantly suppressed IL-1β, tumor necrosis factor-α (TNF-α), IL-8, and IL-6 from human monocytes, and IL-8 and IL-6 from human keratinocytes, respectively. Importantly, silencing of NLRP3 expression by small interfering RNA did not limit NO-np inhibition of IL-1 β secretion from monocytes, and neither TNF-α nor IL-6 secretion, nor inhibition by NO-np was found to be dependent on this pathway. The observed mechanism by which NO-np impacts IL-1β secretion was through inhibition of caspase-1 and IL-1β gene expression. Together, these data suggest that NO-np can effectively prevent P. acnes-induced inflammation by both clearing the organism and inhibiting microbial stimulation of the innate immune response
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Development of a Rapid and High-Throughput Multiplex Real-Time PCR Assay for Mycoplasma hominis and Ureaplasma Species
Bacterial commensals of the human genitourinary tract, Mycoplasma hominis and Ureaplasma species (parvum and urealyticum) can be sexually transmitted, and may cause nongonococcal urethritis, pelvic inflammatory disease, and infertility. Mycoplasma hominis and Ureaplasma species may also cause severe invasive infections in immunocompromised patients. Current culture-based methods for Mycoplasma/Ureaplasma identification are costly and laborious, with a turnaround time between 1 and 2 weeks. We developed a high-throughput, real-time multiplex PCR assay for the rapid detection of M. hominis and Ureaplasma species in urine, genital swab, body fluid, and tissue. In total, 282 specimens were tested by PCR and compared with historic culture results; a molecular reference method was used to moderate discrepancies. Overall result agreement was 99% for M. hominis (97% positive percentage agreement and 100% negative percentage agreement) and 96% for Ureaplasma species (96% positive percentage agreement and 97% negative percentage agreement). Specimen stability was validated for up to 7 days at room temperature. This multiplex molecular assay was designed for implementation in a high-complexity clinical microbiology laboratory. With this method, >90 samples can be tested in one run, with a turnaround time of 4 to 5 hours from specimen extraction to reporting of results. This PCR test is also more labor effective and cheaper than the conventional culture-based test, thus improving laboratory efficiency and alleviating labor shortages
GREEN IGUANAS (\u3ci\u3eIGUANA IGUANA\u3c/i\u3e): THE UNINTENDED CONSEQUENCE OF SOUND WILDLIFE MANAGEMENT PRACTICES IN A SOUTH FLORIDA PARK
We examined the demographic response of the Green Iguana (Iguana iguana) to the removal of Raccoons in an urban maritime state park in southern Florida. The rapid growth of iguanas to sexual maturity in an underexploited, if not vacant, niche contributed to the rapid recruitment of a large and growing population during the four and one half years since removal of its limiting predator. We proffer here that at sites where Green Iguanas and high density Raccoons are syntopic, future Raccoon removal programs should be concurrent with an equally concerted effort to remove resident Green Iguanas. In this fashion, by replacing one limiting predator with another, a population explosion can be prevented and an advantage can be maintained in the local control of this exotic species
Acute glycogen synthase kinase-3 inhibition modulates human cardiac conduction
Glycogen synthase kinase 3 (GSK-3) inhibition has emerged as a potential therapeutic target for several diseases, including cancer. However, the role for GSK-3 regulation of human cardiac electrophysiology remains ill-defined. We demonstrate that SB216763, a GSK-3 inhibitor, can acutely reduce conduction velocity in human cardiac slices. Combined computational modeling and experimental approaches provided mechanistic insight into GSK-3 inhibition-mediated changes, revealing that decreased sodium-channel conductance and tissue conductivity may underlie the observed phenotypes. Our study demonstrates that GSK-3 inhibition in human myocardium alters electrophysiology and may predispose to an arrhythmogenic substrate; therefore, monitoring for adverse arrhythmogenic events could be considered
Maternal and adolescent distress tolerance: The moderating role of gender.
Distress tolerance is defined behaviorally as the ability to maintain goal directed behavior while experiencing physical or psychological distress. Distress tolerance is closely related to emotion regulation, and is a clinically relevant construct contributing to psychopathology across adults and adolescents, yet limited research has examined the development of this construct. A number of studies suggest the importance of parenting in the emergence of emotion regulation capacities in childhood and adolescence. In the current study, we utilize a behavioral measure of distress tolerance to examine whether maternal distress tolerance is related to adolescent distress tolerance, and if this association differs as a function of gender. We also examine the influence of family emotional climate, namely maternal response to adolescent distress and adolescent attachment. Results indicate a significant maternal distress tolerance by adolescent gender interaction, such that maternal distress tolerance predicts adolescent distress tolerance in daughters, but not sons. The family emotional climate variables were unrelated to maternal or adolescent distress tolerance. Taken together, data indicate that maternal distress tolerance is significantly related to the distress tolerance of adolescent daughters, and indicates the potential utility of addressing maternal distress tolerance in clinical work with adolescents
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