761 research outputs found

    A histological investigation of \u3ci\u3eArceuthobium pusillum\u3c/i\u3e infections in \u3ci\u3ePicea rubens\u3c/i\u3e and \u3ci\u3ePicea glauca\u3c/i\u3e

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    Arceuthobium pusillum is a hemiparasite that infects select Picea species. The hosts of A. pusillum do not experience the same symptoms of infection. A. pusillum infections are more fatal to P. marinara, and P. glauca. P. rubens, on the other hand, can survive longer with sustained infection. This presents itself as a contemporary issue because P. glauca, one of the parasite’s most vulnerable hosts, was untethered from ecological competition when old growth forests were subjected to large scale anthropogenic disturbances. These disturbances allowed P. glauca to proliferate, with A. pusillum following. A deeper understanding of the host-species specific responses to A. pusillum infection can broaden general knowledge of parasitic growth and development while also potentially inspiring conservation techniques. This study took advantage of the intrinsic differences between host and parasite to visualize infections in P. rubens and P. glauca, highlighting differences in infection outcome. By illuminating lignin and callose within cross sections of infected P. rubens and P. glauca branches, it was revealed that P. rubens forms dense bands of cells around the cortical strands of infection. These bands form more frequently in P. rubens than in P. glauca and are of a significantly larger area in P. rubens than in P. glauca (t(8), p=0.003, p=0.005). The discovery of the exterior bands is novel and exciting, as the bands are possibly made of callose and potentially facilitate P. rubens survival against A. pusillum infection. The foundational discoveries and results of this study should inspire, and warrant, further analysis

    Characterization of Caenorhabditis Elegans F07A5.4, Human Ortholog of Olfactomedin 1

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    Accurate control of nervous system development is critical for normal brain patterning, and defects in this process can lead to neurological disorders such as schizophrenia and Autism Spectrum Disorder. The transcription factor neurogenin is necessary for the development of neural subtypes and is deeply conserved across species. However, the transcriptional targets of neurogenin are poorly understood, creating an imperative for further study. We have used the nematode Caenorhabditis elegans as a model to better understand ngn-1/neurogenin function. Previous work from our lab revealed that ngn-1 plays a role in nerve ring architecture, and neural cell fate specification. In addition, ngn-1 mutants have an array of neuromuscular defects such as sluggish, uncoordinated movement and precocious egg laying. To help identify downstream targets of ngn-1, we performed a comparative transcriptome on messenger RNA isolated from wild type and ngn-1 mutants. We discovered that F07A5.4 transcript levels are significantly lower in ngn-1 mutants. F07A5.4 is an ortholog of Human olfactomedin (Olfm1), which is a secreted glycoprotein in the conserved olfactomedin family (OLF). In rodents, OLF domain proteins play important roles in neurogenesis, neural crest formation, and cell adhesion. We hypothesize that F07A5.4 is required for establishing normal nervous system architecture in the worm. To investigate this, we have identified alleles from the Million Mutation Project that mutate conserved amino acids in the F07A5.4 protein sequence. This project aims to characterize the phenotype of those alleles and to establish the normal function of F07A5.4 in C. elegans nervous system development

    Localization transition on complex networks via spectral statistics

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    The spectral statistics of complex networks are numerically studied. The features of the Anderson metal-insulator transition are found to be similar for a wide range of different networks. A metal-insulator transition as a function of the disorder can be observed for different classes of complex networks for which the average connectivity is small. The critical index of the transition corresponds to the mean field expectation. When the connectivity is higher, the amount of disorder needed to reach a certain degree of localization is proportional to the average connectivity, though a precise transition cannot be identified. The absence of a clear transition at high connectivity is probably due to the very compact structure of the highly connected networks, resulting in a small diameter even for a large number of sites.Comment: 6 pages, expanded introduction and referencess (to appear in PRE

    Two pup vocalization types are genetically and functionally separable in deer mice

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    Vocalization is a widespread vertebrate social behavior that is essential for fitness in the wild. While many vocal behaviors are highly conserved, heritable features of specific vocalization types can vary both within and between species, raising the questions of why and how some vocal behaviors evolve. Here, using new computational tools to automatically detect and cluster vocalizations into distinct acoustic categories, we compare pup isolation calls across neonatal development in eight taxa of deer mice (genusPeromyscus) and compare them to laboratory mice (C57Bl6/j strain) and free-living, wild house mice (Mus musculus musculus). Whereas bothPeromyscusandMuspups produce ultrasonic vocalizations (USVs),Peromyscuspups also produce a second call type with acoustic features, temporal rhythms, and developmental trajectories that are distinct from those of USVs. In deer mice, these tonal and low frequency “cries” are predominantly emitted in postnatal days one through nine, while USVs are primarily made after day nine. Using playback assays, we show that cries result in a more rapid approach byPeromyscusmothers than USVs, suggesting a role for cries in eliciting parental care early in neonatal development. Using genetic crosses between two sister species of deer mice exhibiting large, innate differences in the acoustic structure of cries and USVs, we find that variation in vocalization rate, duration, and pitch display different degrees of genetic dominance and that cry and USV features can be uncoupled in second-generation hybrids. Taken together, this work shows that vocal behavior can evolve quickly between closely related rodent species in which vocalization types, likely serving distinct functions in communication, are controlled by distinct genetic loci

    Canal wall reconstruction and mastoid obliteration with composite multi-fractured osteoperiosteal flap

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    We used inferior pedicled composite multi-fractured osteoperiosteal flap (CMOF), our original and new surgical approach, to obliterate the mastoid cavity and reconstruct the external auditory canal (EAC) to prevent the open cavity problems. CMOF was used to obliterate the mastoid cavity and reconstruct the EAC in 24 patients (13 women, 11 men; age span 12–51 years) who underwent radical mastoidectomy to treat the chronic otitis media between 1998 and 2004. Small meatoplasty was done in all 24 patients to relive their aesthetical concerns. Temporal bone CT scanning was done to observe the neo-osteogenesis in the mastoidectomy cavity and the CMOF, and the EAC volume was measured postoperatively. All our patients were followed-up for 2 years. The epithelization of the new EAC in our patients was complete at the end of the second month. Cholesteatoma, granulation, and recurrence of osteitis did not occur in any of the patients. We saw the new bone formation filling the mastoid cavity in the postoperative temporal bone CT scanning images. The mean volume of the new EAC on the 24th month was 1.83 ± 0.56 cm(3). We had an almost natural EAC, which owed its existence to the neo-osteogenesis that grows behind the CMOF, which we use to obliterate the mastoid cavity and to reconstruct the EAC

    Predicting fine-scale daily NO2 over Mexico city using an ensemble modeling approach

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    In recent years, there has been growing interest in developing air pollution prediction models to reduce exposure measurement error in epidemiologic studies. However, efforts for localized, fine-scale prediction models have been predominantly focused in the United States and Europe. Furthermore, the availability of new satellite instruments such as the TROPOsopheric Monitoring Instrument (TROPOMI) provides novel opportunities for modeling efforts. We estimated daily ground-level nitrogen dioxide (NO2) concentrations in the Mexico City Metropolitan Area at 1-km2 grids from 2005 to 2019 using a four-stage approach. In stage 1 (imputation stage), we imputed missing satellite NO2 column measurements from the Ozone Monitoring Instrument (OMI) and TROPOMI using the random forest (RF) approach. In stage 2 (calibration stage), we calibrated the association of column NO2 to ground-level NO2 using ground monitors and meteorological features using RF and extreme gradient boosting (XGBoost) models. In stage 3 (prediction stage), we predicted the stage 2 model over each 1-km2 grid in our study area, then ensembled the results using a generalized additive model (GAM). In stage 4 (residual stage), we used XGBoost to model the local component at the 200-m2 scale. The cross-validated R2 of the RF and XGBoost models in stage 2 were 0.75 and 0.86 respectively, and 0.87 for the ensembled GAM. Cross-validated root-mean-squared error (RMSE) of the GAM was 3.95 μg/m3. Using novel approaches and newly available remote sensing data, our multi-stage model presented high cross-validated fits and reconstructs fine-scale NO2 estimates for further epidemiologic studies in Mexico City

    Tear proteomic analysis of Sjogren syndrome patients with dry eye syndrome by two-dimensional-nano-liquid chromatography coupled with tandem mass spectrometry

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    We examined the tear film proteome of patients with Sjögren's syndrome (SS) and dry eye syndrome (group A), patients with dry eye symptoms (group B) and normal volunteers (group C). Tear samples were pooled from 8 subjects from each group and were subjected to two-dimensional-nano-liquid chromatography coupled with tandem mass spectrometry (2D-nano-LC-MS/MS). The tear breakup time for group A was significantly reduced compared with group B and C (P < 0.001). Group A (Schirmer I test, 2.13 +/- 2.38 mm/5 min) had markedly lower tear volume than group B (5.94 +/- 4.75 mm/5 min) and C (14.44 +/- 6.57 mm/5 min) (P < 0.001). Group A had significantly higher normalized tear protein content (1.8291 +/- 0.2241 mu g/mm) than group B (1.0839 +/- 0.1120 mu g/mm) (P = 0.001) and C (0.2028 +/- 0.0177 mu g/mm) (P = 0.001). The 2D-nano-LC-MS/MS analysis identified a total of 435 proteins, including 182 (54.8%),247 (74.4%) and 278 (83.7%) in group A, B, and C, respectively, with 56 (16.7%) proteins including defensin alpha 1, clusterin and lactotransferrin unique to group A. In conclusion, dry eye syndrome in SS patients is associated with an altered proteomic profile with dysregulated expression of proteins involved in a variety of important cellular process including inflammation, immunity, and oxidative stress
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