75 research outputs found
Decreased Polysaccharide Feruloylation Compromises Plant Cell Wall Integrity and Increases Susceptibility to Necrotrophic Fungal Pathogens
No full textThe complexity of cell wall composition and structure determines the strength, flexibility, and function of the primary cell wall in plants. However, the contribution of the various components to cell wall integrity and function remains unclear. Modifications of cell wall composition can induce plant responses known as Cell Wall Integrity control. In this study, we used transgenic expression of the fungal feruloyl esterase AnFAE to examine the effect of post-synthetic modification of Arabidopsis and Brachypodium cell walls. Transgenic Arabidopsis plants expressing AnFAE showed a significant reduction of monomeric ferulic acid, increased amounts of wall-associated extensins, and increased susceptibility to Botrytis cinerea, compared with wild type. Transgenic Brachypodium showed reductions in monomeric and dimeric ferulic acids and increased susceptibility to Bipolaris sorokiniana. Upon infection, transgenic Arabidopsis and Brachypodium plants also showed increased expression of several defense-related genes compared with wild type. These results demonstrate a role, in both monocot and dicot plants, of polysaccharide feruloylation in plant cell wall integrity, which contributes to plant resistance to necrotrophic pathogens
Correction to: Metabolic reprogramming of T regulatory cells in the hypoxic tumor microenvironment (Cancer Immunology, Immunotherapy, (2021), 70, 8, (2103-2121), 10.1007/s00262-020-02842-y)
No full textin the hypoxic tumor microenvironment, written by Varun Sasidharan Nair, Reem Saleh, Salman M. Toor, Farhan S. Cyprian and Eyad Elkord, was originally published electronically on the publisher’s internet portal on 03 February 2021 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed on 25 May 2021 to © The Author(s) 2021 and this article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. The original article has been corrected
'Hammondia heydorni' from the Arabian mountain gazelle and red fox in Saudi Arabia
No full textUnsporulated oocysts were detected in the feces of an Arabian red fox (Vulpes vulpes arabica) between 6 and 8 days after it had been fed meat from Arabian mountain gazelles (Gazella gazella) known to contain sarcocysts. No oocysts were discovered in the feces of other experimental cubs, although sporocysts of Sarcocystis spp. were passed subsequently by all cubs that were fed gazelle meat, including those fed with reem (G. subgutturosa marica). The oocysts sporulated in 3 days at room temperature (25 ± 2 C); they were 10.9 ± 1.4 × 10.1 ± 1.3 μm, with 2 sporocysts measuring 6.0 ± 0.6 × 4.7 ± 0.8 μm, each with 4 sporozoites. Sporulated oocysts were identified as those of Hammondia heydorni using molecular and standard morphometric techniques. Sequence differences between 2 fox and 3 dog isolates of H. heydorni were detected and allowed differentiation between the 2 populations of the organism. The involvement of Neospora caninum was excluded using molecular methods. The Arabian red fox and the Arabian mountain gazelle in Saudi Arabia are new, definitive and intermediate hosts for H. heydorni
The length of primary roots and hypocotyls of AnF and wild type Arabidopsis seedlings grown in dark measured after 6 days after germination.
No full textTwo independent sets of growth tests were performed where, in total, 118 AnF and 129 wild type seedlings were measured. Bars represent mean ± standard deviation of the mean. *significantly different (t-test, p<0.01).</p
Coexpression of Fungal Cell Wall-Modifying Enzymes Reveals Their Additive Impact on Arabidopsis Resistance to the Fungal Pathogen, <i>Botrytis cinerea</i>
No full textThe plant cell wall (CW) is an outer cell skeleton that plays an important role in plant growth and protection against both biotic and abiotic stresses. Signals and molecules produced during host–pathogen interactions have been proven to be involved in plant stress responses initiating signal pathways. Based on our previous research findings, the present study explored the possibility of additively or synergistically increasing plant stress resistance by stacking beneficial genes. In order to prove our hypothesis, we generated transgenic Arabidopsis plants constitutively overexpressing three different Aspergillus nidulans CW-modifying enzymes: a xylan acetylesterase, a rhamnogalacturonan acetylesterase and a feruloylesterase. The two acetylesterases were expressed either together or in combination with the feruloylesterase to study the effect of CW polysaccharide deacetylation and deferuloylation on Arabidopsis defense reactions against a fungal pathogen, Botrytis cinerea. The transgenic Arabidopsis plants expressing two acetylesterases together showed higher CW deacetylation and increased resistance to B. cinerea in comparison to wild-type (WT) Col-0 and plants expressing single acetylesterases. While the expression of feruloylesterase alone compromised plant resistance, coexpression of feruloylesterase together with either one of the two acetylesterases restored plant resistance to the pathogen. These CW modifications induced several defense-related genes in uninfected healthy plants, confirming their impact on plant resistance. These results demonstrated that coexpression of complementary CW-modifying enzymes in different combinations have an additive effect on plant stress response by constitutively priming the plant defense pathways. These findings might be useful for generating valuable crops with higher protections against biotic stresses
The Impact of Residency Programs on Clinical Decision-Making and Leadership Skills Among New Saudi Graduate Nurses
No full textThis work was embargoed by the author and will not be publicly available until May 2016.Saudi Arabia is challenged by a nursing shortage as are several other countries. Due to the intense working environment, increasing patient acuity, and complex technologies, health care settings create challenges for new graduate nurses. Thus, health care institutions have adopted residency programs to help new graduate nurses to become fully competent and transition from student nurses to independent practicing nurses and bedside leaders. Nurse residency programs are reported to have proven beneficial and positive effects on new graduate nurses. The purpose of this exploratory, descriptive study was to assess the impact of residency programs on the clinical decision-making and leadership skills of new Saudi graduate nurses who had completed a residency program within 1 week to 3 months of the time this study was conducted, and new Saudi graduate nurses who did not participate in residency programs. The conceptual framework that guided this study was Benner's Novice to Expert model. A convenience sample of n = 98 new graduate nurses was collected from three hospitals in Saudi Arabia. A self-administered questionnaire was used to collect data. Clinical decision-making skills were measured using Clinical Decision Making in Nursing Scale and clinical leadership skills were measured using the Clinical Leadership Survey. An independent t-test, bivariate association, and multiple linear regression analysis were utilized to test hypotheses concerning different groups. The findings revealed a significant difference between the residency program group and the nonresidency program group in clinical decision-making (t = 23.25, p = 0.000) and leadership skills (t = 10.48, p = 0.000). However, there were no significant differences in the average number of clinical decision-making and leadership skills based on the length of their residency program (6 months vs. 12 months). In addition, a moderate positive correlation was found between overall grade point average (GPA) and total clinical decision-making scores (r = 0.365, p = 0.000), and overall GPA and total clinical leadership skills (r = 0.440, p = 0.000). The clinical decision-making regression model explained 86.9% of the variance in total clinical decision making by the differences in age, overall GPA, and enrollment in a residency program. In addition, the clinical leadership skills regression model explained 60.6% of variance in total clinical leadership skills by the differences in age, overall GPA, total clinical decision-making scores, and enrollment in a residency program. This study is one of the first such studies that examined the impact of residency programs on clinical decision-making and leadership skills' of new Saudi graduate nurses who completed a residency program. The findings of this study indicate that there is a need to implement more residency programs in hospitals of Saudi Arabia. It is imperative that nurse managers and policy makers in Saudi Arabia consider these findings to improve nurses' clinical decision-making and leadership skills, which will in turn improve patient care
Cutting efficiency of diamond burs in CADCAM dental ceramics and resulting surface characteristics
No full textPLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please log in with a valid BU account to access and click Download. If you are the author of this work and would like to make it publicly available, please contact [email protected] (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2015 (Department of Restorative Sciences and Biomaterials).Includes bibliographic references: leaves 128-132.Objectives: the purpose of this study is to evaluate the cutting efficiency of diamond burs under different conditions (diamond grits, Cutting force, and coolant) when machining 3 CAD/CAM dental ceramics. Also, the study aims at examining the resulting surface topography, edge chipping and kerf size.
Materials and methods: Coarse, medium, and fine grit diamond burs (n=10) from 3 manufacturers (Meisinger, Komet, and Brasseler) were used to make 3 cuts each, in fully sintered zirconia blocks (TZ-3YSB-E, TOSOH), fully crystalized lithium-disilicate (IPS e.max CAD, Ivoclar), and feldspathic porcelain blocks (VitaBIocs TriLuxe Forte, Vita) using an electric handpiece running at 200,000 rpm. The cutting forces for zirconia and e.max were 1.47N and 1.96N and for TriLuxe Forte 0.98N. Three Cooling liquids (tapwater, 0.9% saline, and 1:5 mouthwash) at a rate of 100ml/min were used. The ceramic blocks were fixed on a sliding base running on 2 rods using frictionless ball bearings. The cutting distance was recorded using LVDT connected to LabView software. Average cutting rate was calculated for each cut. Instruments weighed and evaluated using SEM before, during and after experiments. Kerfs and edge chippings seen around each cut were recorded using optical microscope connected to a high definition video micrometer. The blocks were then sectioned to reveal machined surfaces for surface roughness measurement. Statistical analysis was conducted using student t-teSt, ANOVA and Tukey post hoc test at [alpha]=0.05.
Results: one-way ANOVA revealed a significant difference in material removal rate between the three substrates (P0.05). Large diamond grits produced significantly larger kerfs (P<0.0001). Surface roughness was found to be significantly larger in TriLuxe Forte than other substrates (P<0.0001).
Conclusions: A significant differences in material removal rate was found between the three substrates with feldspathic porcelain being the highest followed by e.max then zirconia. Also, bur cutting rate was found to decline with consecutive cuts. Similar grits from different manufacturers behave differently under similar testing conditions. However, fine diamond burs had significantly smaller cutting rates than other grits for all manufacturers. Increasing the cutting force can improve material removal rate. In this study, it was found that the effect of cooling liquid is material dependent with mouthwash improving feldspathic porcelain removal rate and saline improving that of zirconia. Edge chipping increased when the diamond grits were bigger and it was found to be more on bur exit side. Feldspathic porcelain had the highest surface roughness values compared to other substrates
Searching for the extra-tidal stars of globular clusters using high-dimensional analysis and a core particle spray code
No full textThree-body interactions can eject stars from the core of a globular cluster,
causing them to enter the Galactic halo as extra-tidal stars. While finding
extra-tidal stars is imperative for understanding cluster evolution, connecting
isolated extra-tidal field stars back to their birth cluster is extremely
difficult. In this work, we present a new methodology consisting of
high-dimensional data analysis and a particle spray code to identify
extra-tidal stars of any Galactic globular cluster using M3 as a case study.
Using the t-Stochastic Neighbour Embedding (t-SNE) and Uniform Manifold
Approximation and Projection (UMAP) machine learning dimensionality reduction
algorithms, we first identify a set of 103 extra-tidal candidates in the APOGEE
DR17 data catalogue with chemical abundances similar to M3 stars. To confirm
each candidate's extra-tidal nature, we introduce corespray - a new
Python-based three-body particle spray code that simulates extra-tidal stars
for any Galactic globular cluster. Using Gaia EDR3 proper motions and APOGEE
DR17 radial velocities, we apply multivariate Gaussian modelling and an extreme
deconvolution to identify the extra-tidal candidates that are more likely to be
associated with a distribution of corespray-simulated M3 extra-tidal stars than
the field. Through these methods, we identify 10 new high-probability
extra-tidal stars produced via three-body interactions in M3. We also explore
whether any of our extra-tidal candidates are consistent with being ejected
from M3 through different dynamical processes. Future applications of corespray
will yield better understandings of core dynamics, star formation histories and
binary fractions in globular clusters.Comment: 16 pages, 8 figures, 3 tables. Accepted for publication in Monthly
Notices of the Royal Astronomical Societ
Post-Synthetic Defucosylation of AGP by Aspergillus nidulans α-1,2-Fucosidase Expressed in Arabidopsis Apoplast Induces Compensatory Upregulation of α-1,2-Fucosyltransferases.
No full textCell walls are essential components of plant cells which perform a variety of important functions for the different cell types, tissues and organs of a plant. Besides mechanical function providing cell shape, cell walls participate in intercellular communication, defense during plant-microbe interactions, and plant growth. The plant cell wall consists predominantly of polysaccharides with the addition of structural glycoproteins, phenolic esters, minerals, lignin, and associated enzymes. Alterations in the cell wall composition created through either changes in biosynthesis of specific constituents or their post-synthetic modifications in the apoplast compromise cell wall integrity and frequently induce plant compensatory responses as a result of these alterations. Here we report that post-synthetic removal of fucose residues specifically from arabinogalactan proteins in the Arabidopsis plant cell wall induces differential expression of fucosyltransferases and leads to the root and hypocotyl elongation changes. These results demonstrate that the post-synthetic modification of cell wall components presents a valuable approach to investigate the potential signaling pathways induced during plant responses to such modifications that usually occur during plant development and stress responses
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