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Found 37684 matches. Displaying 2211-2220
Trible W, McKenzie SK, Kronauer DJC
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Globally invasive populations of the clonal raider ant are derived from Bangladesh

BIOLOGY LETTERS 2020 JUN 24; 16(6):? Article 20200105
Identifying the native range of invasive species is useful to understand their evolution and natural history, as well as to develop new methods to control potentially harmful introduced organisms. The clonal raider ant,Ooceraea biroi, is an introduced species and an increasingly important social insect model organism, but its native range remains unknown. Here, we report a new series ofO. biroicollections from Bangladesh, Singapore, Vietnam and China. We use a molecular phylogeny constructed with five gene fragments from 27 samples to determine that invasive lineages ofO. biroioriginated in Bangladesh. These lineages may have spread from Bangladesh via the historically significant Bay of Bengal shipping ports.Ooceraea biroishares multiple features of its biology with other introduced ants, including parthenogenesis, retention of heterozygosity and presence of multiple egg-layers in the colony. Using laboratory rearing and microsatellite markers, we show that colonies collected from disturbed habitat in Bangladesh have these traits in common with colonies from the invasive range. Ancestral populations with sexual reproduction in primary habitats either remain to be discovered or have gone extinct. Our findings advance our understanding of the global spread of the clonal raider ant and highlight a suite of general traits that make certain ants prone to becoming invasive.
Dhar N, Sarangapani S, Reddy VA, Kumar N, Panicker D, Jin JJ, Chua NH, Sarojam R
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Characterization of a sweet basil acyltransferase involved in eugenol biosynthesis

JOURNAL OF EXPERIMENTAL BOTANY 2020 JUN 22; 71(12):3638-3652
Sweet basil (Ocimum basilicum) plants produce its characteristic phenylpropene-rich essential oil in specialized structures known as peltate glandular trichomes (PGTs). Eugenol and chavicol are the major phenylpropenes produced by sweet basil varieties whose synthetic pathways are not fully elucidated. Eugenol is derived from coniferyl acetate by a reaction catalysed by eugenol synthase. An acyltransferase is proposed to convert coniferyl alcohol to coniferyl acetate which is the first committed step towards eugenol synthesis. Here, we perform a comparative next-generation transcriptome sequencing of different tissues of sweet basil, namely PGT, leaf, leaf stripped of PGTs (leaf-PGT), and roots, to identify differentially expressed transcripts specific to PGT. From these data, we identified a PGT-enriched BAHD acyltransferase gene ObCAAT1 and functionally characterized it. In vitro coupled reaction of ObCAAT1 with eugenol synthase in the presence of coniferyl alcohol resulted in eugenol production. Analysis of ObCAAT1-RNAi transgenic lines showed decreased levels of eugenol and accumulation of coniferyl alcohol and its derivatives. Coniferyl alcohol acts as a common substrate for phenylpropene and lignin biosynthesis. No differences were found in total lignin content of PGTs and leaves of transgenic lines, indicating that phenylpropene biosynthesis is not coupled to lignification in sweet basil.
Nomura T, Wu JN, Kabashima K, Guttman-Yassky E
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Endophenotypic Variations of Atopic Dermatitis by Age, Race, and Ethnicity

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY-IN PRACTICE 2020 JUN; 8(6):1840-1852
Atopic dermatitis (AD) is a heterogeneous disease with unique clinical manifestations across age groups and race/ethnicities. Characteristic molecular mechanisms, known as endotypes, including IgE level, status of epidermal barrier genes, and differential cytokine axes activation in the background of T(H)2 upregulation, are also implicated. In adults, the T(H)22, T(H)17, and T(H)1 pathways are involved, and a weakened epidermal barrier is characteristic. In contrast, pediatric patients exhibit less T(H)1 activation, and defects in epidermal lipid metabolism contribute to their barrier defect. European American patients are characterized by higher differential T(H)2/T(H)22 activation, lower expression of the T(H)1/T(H)17 axes, and suppression of filaggrin (FLG) and loricrin gene expressions. Asian patients have accentuated polarity of the T(H)22/T(H)17 pathways, and also exhibit epidermal barrier defects despite relative maintenance of FLG and loricrin expression. African American patients do not exhibit FLG mutations and have distinct attenuation of T(H)17/T(H)1 axes activation. Dissecting the molecular basis of AD endotypes has provided an important framework upon which targeted therapeutics are being developed. An increased understanding of these subtypes and the alteration of biomarkers that correlate with disease can ultimately push AD treatment in an era of personalized medicine. (c) 2020 American Academy of Allergy, Asthma & Immunology
Cajamarca SA, Norris EH, van der Weerd L, Strickland S, Ahn HJ
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Cerebral amyloid angiopathy-linked beta-amyloid mutations promote cerebral fibrin deposits via increased binding affinity for fibrinogen

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2020 JUN 23; 117(25):14482-14492
Cerebral amyloid angiopathy (CAA), where beta-amyloid (A beta)deposits around cerebral blood vessels, is a major contributor of vascular dysfunction in Alzheimer's disease (AD) patients. However, the molecular mechanism underlying CAA formation and CAA-induced cerebrovascular pathology is unclear. Hereditary cerebral amyloid angiopathy (HCAA) is a rare familial form of CAA in which mutations within the (A beta) peptide cause an increase in vascular deposits. Since the interaction between A beta and fibrinogen increases CAA and plays an important role in cerebrovascular damage in AD, we investigated the role of the A beta-fibrinogen interaction in HCAA pathology. Our work revealed the most common forms of HCAA-linked mutations, Dutch (E22Q) and Iowa (D23N), resulted in up to a 50-fold stronger binding affinity of A beta for fibrinogen. In addition, the stronger interaction between fibrinogen and mutant A beta s led to a dramatic perturbation of clot structure and delayed fibrinolysis. Immunofluorescence analysis of the occipital cortex showed an increase of fibrin(ogen)/A beta codeposition, as well as fibrin deposits in HCAA patients, compared to early-onset AD patients and nondemented individuals. Our results suggest the HCAA-type Dutch and Iowa mutations increase the interaction between fibrinogen and A beta, which might be central to cerebrovascular pathologies observed in HCAA.
Jishage M, Ito K, Chu CS, Wang XL, Yamaji M, Roeder RG
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Transcriptional down-regulation of metabolic genes by Gdown1 ablation induces quiescent cell re-entry into the cell cycle

GENES & DEVELOPMENT 2020 JUN 1; 34(11-12):767-784
Liver regeneration and metabolism are highly interconnected. Here, we show that hepatocyte-specific ablation of RNA polymerase II (Pol II)-associated Gdown1 leads to down-regulation of highly expressed genes involved in plasma protein synthesis and metabolism, a concomitant cell cycle re-entry associated with induction of cell cycle-related genes (including cyclin D1), and up-regulation of p21 through activation of p53 signaling. In the absence of p53, Gdown1-deficient hepatocytes show a severe dysregulation of cell cycle progression, with incomplete mitoses, and a premalignant-like transformation. Mechanistically, Gdown1 is associated with elongating Pol II on the highly expressed genes and its ablation leads to reduced Pol II recruitment to these genes, suggesting that Pol II redistribution may facilitate hepatocyte re-entry into the cell cycle. These results establish an important physiological function for a Pol II regulatory factor (Gdown1) in the maintenance of normal liver cell transcription through constraints on cell cycle re-entry of quiescent hepatocytes.
Scopino K, Williams E, Elsayed A, Barr WA, Krizanc D, Thayer KM, Weir MP
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A Ribosome Interaction Surface Sensitive to mRNA GCN Periodicity

BIOMOLECULES 2020 JUN; 10(6):? Article 849
A longstanding challenge is to understand how ribosomes parse mRNA open reading frames (ORFs). Significantly, GCN codons are over-represented in the initial codons of ORFs of prokaryote and eukaryote mRNAs. We describe a ribosome rRNA-protein surface that interacts with an mRNA GCN codon when next in line for the ribosome A-site. The interaction surface is comprised of the edges of two stacked rRNA bases: the Watson-Crick edge of 16S/18S rRNA C1054 and the adjacent Hoogsteen edge of A1196 (Escherichia coli 16S rRNA numbering). Also part of the interaction surface, the planar guanidinium group of a conserved Arginine (R146 of yeast ribosomal protein Rps3) is stacked adjacent to A1196. On its other side, the interaction surface is anchored to the ribosome A-site through base stacking of C1054 with the wobble anticodon base of the A-site tRNA. Using molecular dynamics simulations of a 495-residue subsystem of translocating ribosomes, we observed base pairing of C1054 to nucleotide G at position 1 of the next-in-line codon, consistent with previous cryo-EM observations, and hydrogen bonding of A1196 and R146 to C at position 2. Hydrogen bonding to both of these codon positions is significantly weakened when C at position 2 is changed to G, A or U. These sequence-sensitive mRNA-ribosome interactions at the C1054-A1196-R146 (CAR) surface potentially contribute to the GCN-mediated regulation of protein translation.
Nasca C, Dobbin J, Bigio B, Watson K, de Angelis P, Kautz M, Cochran A, Mathe AA, Kocsis JH, Lee FS, Murrough JW, McEwen BS, Rasgon N
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Insulin receptor substrate in brain-enriched exosomes in subjects with major depression: on the path of creation of biosignatures of central insulin resistance

MOLECULAR PSYCHIATRY 2020 JUN 15; ?(?):?
Insulin signaling is critical for neuroplasticity, cerebral metabolism as well as for systemic energy metabolism. In rodent studies, impaired brain insulin signaling with resultant insulin resistance (IR) modulates synaptic plasticity and the corresponding behavioral functions. Despite discoveries of central actions of insulin, in vivo molecular mechanisms of brain IR until recently has proven difficult to study in the human brain. In the current study, we leveraged recent technological advances in molecular biology and herein report an increased number of exosomes enriched for L1CAM, a marker predominantly expressed in the brain, in subjects with major depressive disorder (MDD) as compared with age- and sex-matched healthy controls (HC). We also report increased concentration of the insulin receptor substrate-1 (IRS-1) in L1CAM(+)exosomes in subjects with MDD as compared with age- and sex-matched HC. We found a relationship between expression of IRS-1 in L1CAM(+)exosomes and systemic IR as assessed by homeostatic model assessment of IR in HC, but not in subjects with MDD. The increased IRS-1 levels in L1CAM(+)exosomes were greater in subjects with MDD and were associated with suicidality and anhedonia. Finally, our data suggested sex differences in serine-312 phosphorylation of IRS-1 in L1CAM(+)exosomes in subjects with MDD. These findings provide a starting point for creating mechanistic framework of brain IR in further development of personalized medicine strategies to effectively treat MDD.
Iyengar MF, Soto LF, Requena D, Ruiz-Alejos AO, Huaylinos Y, Velasquez R, Bernabe-Ortiz A, Gilman RH
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Tear biomarkers and corneal sensitivity as an indicator of neuropathy in type 2 diabetes

DIABETES RESEARCH AND CLINICAL PRACTICE 2020 MAY; 163(?):? Article 108143
Aims: Explore potential of 31 tear biomarkers involved in screening for diabetic peripheral neuropathy (DPN). Assess the utility of aesthesiometry for measuring corneal damage in DPN and determine optimal cutoff point for detecting DPN. Methods: Screening test pilot study recruited 90 participants from a tertiary hospital in Lima, Peru. Participants were grouped by diabetes and neuropathy status. Tears collected on Schirmer strips, and proteins measured by both ELISA and multiplex-bead assay. Corneal sensitivity was measured by aesthesiometry, and DPN by vibration perception threshold testing. Results: There were 89 participants included in the analysis. The mean age was 55.7 +/- 1.46, and 58.4% were female. MMP-9 and TGF-alpha concentrations were higher in participants with DPN versus diabetes alone, though not significant. Aesthesiometry was decreased in individuals with DPN when compared to participants with diabetes alone (p < 0.01) and normal controls (p < 0.01). Optimal cutoff point for aesthesiometry was found to be 5.8 cm, with 79% sensitivity and 75% specificity. Conclusions: Tears are an insufficient standalone tool for detecting DPN based on the biomarkers analyzed. Aesthesiometry is a simple, inexpensive, and accurate method to assess corneal damage associated with moderate-severe DPN, and its integration into screening practices has potential to improve detection of DPN in poor-resource settings. (C) 2020 Elsevier B.V. All rights reserved.
Gleicher N, Albertini DF, Barad DH, Homer H, Modi D, Murtinger M, Patrizio P, Orvieto R, Takahashi S, Weghofer A, Ziebe S, Noyes N
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The 2019PGDISposition statement on transfer of mosaic embryos within a context of new information on PGT-A

REPRODUCTIVE BIOLOGY AND ENDOCRINOLOGY 2020 MAY 29; 18(1):? Article 57
Background A recently published Position Statement (PS) by thePreimplantation Genetics Diagnosis International Society (PGDIS)regarding utilization of preimplantation genetic testing for aneuploidy (PGT-A) in association with in vitro fertilization (IVF) contained inaccuracies and misrepresentations. Because opinions issued by thePGDIShave since 2016 determined worldwide IVF practice, corrections appear of importance. Methods TheInternational Do No Harm Group in IVF (IDNHG-IVF)is a spontaneously coalesced body of international investigators, concerned with increasing utilization of add-ons to IVF. It is responsible for the presented consensus statement, which as a final document was reached after review of the pertinent literature and again revised after the recent publication of the STAR trial and related commentaries. Results In contrast to the PGDIA-PS, we recommend restrictions to the increasing, and by IVF centers now often even mandated, utilization of PGT-A in IVF cycles. While PGT-A has been proposed as a tool for achieving enhanced singleton livebirth outcomes through embryo selection, continued false-positive rates and increasing evidence for embryonic self-correction downstream from the testing stage, has ledIDNHG-IVFto conclude that currently available data are insufficient to impose overreaching recommendations for PGT-A utilization. Discussion Here presented consensus offers an alternative to the 2019PGDISposition statement regarding utilization of preimplantation genetic testing for aneuploidy (PGT-A) in association with in vitro fertilization (IVF). Mindful of what appears to offer best outcomes for patients, and in full consideration of patient autonomy, here presented opinion is based on best available evidence, with the goal of improving safety and efficacy of IVF and minimizing wastage of embryos with potential for healthy births. Conclusions As thePGDISnever suggested restrictions on clinical utilization of PGT-A in IVF, here presented rebuttal represents an act of self-regulation by parts of the IVF community in attempts to control increasing utilization of different unproven recent add-ons to IVF.
Frew JW, Jiang CS, Singh N, Grand D, Navrazhina K, Vaughan R, Krueger JG
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Clinical response rates, placebo response rates, and significantly associated covariates are dependent on choice of outcome measure in hidradenitis suppurativa: A post hoc analysis of PIONEER 1 and 2 individual patient data

JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY 2020 MAY; 82(5):1150-1157
Background: The hidradenitis suppurativa clinical response (HiSCR) is the gold standard primary outcome measure for hidradenitis suppurativa clinical trials; however, it does not assess the presence of draining tunnels, a common finding in advanced disease. It is unclear what the effect of the presence or absence of draining tunnels has on the efficacy of adalimumab therapy in moderate and advanced disease. Objectives: We evaluated the efficacy of adalimumab versus placebo using the International Hidradenitis Suppurativa Severity Scoring System (IHS4). Additionally, we assessed the effect of draining tunnels on therapeutic response as measured by both the HiSCR and change in nodule counts. Methods: Reanalysis was conducted with the IHS4 and PIONEER 1 and 2 individual patient data. Both binary outcomes (achieving HiSCR and achieving change in IHS4 severity category) and continuous outcomes (nodule counts and IHS4 score) were calculated with R. Regression modeling was undertaken to assess the effect of draining tunnels and other variables. P<.05 was considered statistically significant. Results: The significance of adalimumab therapy depended on the outcome measure used. Placebo response rates were highest when binary outcome measures were used. Draining tunnels, smoking, antibiotics, and body mass index influenced HiSCR response in PIONEER 2. Significant differences in disease severity were observed between PIONEER 1 and 2 data sets. Conclusions: Elevated placebo response rates in PIONEER 1 and 2 are partially attributable to the use of binary outcome measures. Draining tunnels influence clinical response as measured by HiSCR and nodule counts in PIONEER 2. Further investigation into the effect of body mass index on clinical response is required.