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Found 37769 matches. Displaying 1621-1630
Thaler DS
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Is Global Microbial Biodiversity Increasing, Decreasing, or Staying the Same?

FRONTIERS IN ECOLOGY AND EVOLUTION 2021 APR 19; 9(?):? Article 565649
Animal and plant biodiversity is decreasing. In contrast, the global direction and the pace of change in microbial, including viral, biodiversity is unknown. Important niches for microbial diversity occur in highly specific associations with plants and animals, and these niches are lost as hosts become extinct. The taxonomic diversity of human gut bacteria is reported to be decreasing. On the other hand, SARS-CoV-2 variation is increasing. Where microbes are concerned, Darwin's "tangled bank" of interdependent organisms may be composed mostly of other microbes. There is the likelihood that as some classes of microbes become extinct, others evolve and diversify. A better handle on all processes that affect microbial biodiversity and their net balance is needed. Lack of insight into the dynamics of evolution of microbial biodiversity is arguably the single most profound and consequential unknown with regard to human knowledge of the biosphere. If some or all parts of microbial diversity are relentlessly increasing, then survey approaches may be too slow to ever catch up. New approaches, including single-molecule or single-cell sequencing in populations, as well as focused attention on modulators and vectors of vertical and horizontal evolution may offer more direct insights into some aspects of the pace of microbial evolution.
Kronenberg ZN, Rhie A, Koren S, Concepcion GT, Peluso P, Munson KM, Porubsky D, Kuhn K, Mueller KA, Low WY, Hiendleder S, Fedrigo O, Liachko I, Hall RJ, Phillippy AM, Eichler EE, Williams JL, Smith TPL, Jarvis ED, Sullivan ST, Kingan SB
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Extended haplotype-phasing of long-read de novo genome assemblies using Hi-C

NATURE COMMUNICATIONS 2021 APR 28; 12(1):? Article 1935
Haplotype-resolved genome assemblies are important for understanding how combinations of variants impact phenotypes. To date, these assemblies have been best created with complex protocols, such as cultured cells that contain a single-haplotype (haploid) genome, single cells where haplotypes are separated, or co-sequencing of parental genomes in a trio-based approach. These approaches are impractical in most situations. To address this issue, we present FALCON-Phase, a phasing tool that uses ultra-long-range Hi-C chromatin interaction data to extend phase blocks of partially-phased diploid assembles to chromosome or scaffold scale. FALCON-Phase uses the inherent phasing information in Hi-C reads, skipping variant calling, and reduces the computational complexity of phasing. Our method is validated on three benchmark datasets generated as part of the Vertebrate Genomes Project (VGP), including human, cow, and zebra finch, for which high-quality, fully haplotype-resolved assemblies are available using the trio-based approach. FALCON-Phase is accurate without having parental data and performance is better in samples with higher heterozygosity. For cow and zebra finch the accuracy is 97% compared to 80-91% for human. FALCON-Phase is applicable to any draft assembly that contains long primary contigs and phased associate contigs. Methods to produce haplotype-resolved genome assemblies often rely on access to family trios. The authors present FALCON-Phase, a tool that combines ultra-long range Hi-C chromatin interaction data with a long read de novo assembly to extend haplotype phasing to the contig or scaffold level.
Elnabawi YA, Garshick MS, Tawil M, Barrett TJ, Fisher EA, Lo Sicco K, Neimann AL, Scher JU, Krueger J, Berger JS
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CCL20 in psoriasis: A potential biomarker of disease severity, inflammation, and impaired vascular health

JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY 2021 APR; 84(4):913-920
Background: Psoriasis is associated with increased cardiovascular risk that is not captured by traditional proinflammatory biomarkers. Objective: To investigate the relationship between Psoriasis Area and Severity Index, circulating proinflammatory biomarkers, and vascular health in psoriasis. Methods: In patients with psoriasis and in age and sex-matched controls, 273 proteins were analyzed with the Proseek Multiplex Cardiovascular disease reagents kit and Inflammatory reagents kit (Olink Bioscience), whereas vascular endothelial inflammation and health were measured via direct transcriptomic analysis of brachial vein endothelial cells. Results: In psoriasis, chemokine ligand 20 (CCL20), interleukin (IL) 6, and IL-17A were the top 3 circulating proinflammatory cytokines. Vascular endothelial inflammation correlated with CCL20 (r = 0.55; P < .001) and less so with IL-6 (r = 0.36; P = .04) and IL-17A (r = 0.29; P = .12). After adjustment for potential confounders, the association between CCL20 and vascular endothelial inflammation remained significant (beta = 1.71; P = .02). In nested models, CCL20 added value (chi(2) = 79.22; P < .001) to a model already incorporating the Psoriasis Area and Severity Index, Framingham risk, high-sensitivity C-reactive protein, Il-17A, and IL-6 (chi(2) = 48.18; P < .001) in predicting vascular endothelial inflammation. Limitations: Our study was observational and did not allow for causal inference in the relationship between CCL20 and cardiovascular risk. Conclusion: We demonstrate that CCL20 expression has a strong association with vascular endothelial inflammation, reflects systemic inflammation, and may serve as a potential biomarker of impaired vascular health in psoriasis.
Jakhanwal S, Cress BF, Maguin P, Lobba MJ, Marraffini LA, Doudna JA
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A CRISPR-Cas9-integrase complex generates precise DNA fragments for genome integration

NUCLEIC ACIDS RESEARCH 2021 APR 6; 49(6):3546-3556
CRISPR-Cas9 is an RNA-guided DNA endonuclease involved in bacterial adaptive immunity and widely repurposed for genome editing in human cells, animals and plants. In bacteria, RNA molecules that guide Cas9 ' s activity derive from foreign DNA fragments that are captured and integrated into the host CRISPR genomic locus by the Cas1-Cas2 CRISPR integrase. How cells generate the specific lengths of DNA required for integrase capture is a central unanswered question of type II-A CRISPR-based adaptive immunity. Here, we show that an integrase supercomplex comprising guide RNA and the proteins Cas1, Cas2, Csn2 and Cas9 generates precisely trimmed 30-base pair DNA molecules required for genome integration. The HNH active site of Cas9 catalyzes exonucleolytic DNA trimming by a mechanism that is independent of the guide RNA sequence. These results show that Cas9 possesses a distinct catalytic capacity for generating immunological memory in prokaryotes.
El-Etr M, Akwa Y, Rame M, Schumacher M, Sitruk-Ware R
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Nestorone(R), a 19nor-progesterone derivative boosts remyelination in an animal model of demyelination

CNS NEUROSCIENCE & THERAPEUTICS 2021; 27(4):464-469
Introduction We previously showed that Nestorone(R) (NES), a synthetic progestin structurally related to progesterone, stimulated remyelination of the corpus callosum in a Cuprizone (CUP) mouse model of demyelination in intact females by promoting replenishment with mature oligodendrocytes (OL) (Glia. 2015;63:104-117). Here, we further investigated the underlying mechanisms of this promyelinating effect. Methods We explored whether NES, applied subcutaneously through Alzet mini-osmotic pumps, regulates specific transcription factors involved in oligodendrocyte progenitor cell (OPC) proliferation and their differentiation into mature OL, using RT-qPCR and Western Blot analysis. Results Our present data show that in comparison to controls, a one-week treatment with NES, through Alzet mini-osmotic pumps, enhanced the production of three relevant transcription factor mRNAs encoding Olig2, Myt1, and Sox17. After 3 weeks, NES treatment reversed the effect of CUP on the levels of corresponding Olig2, Myt1, and Sox17 proteins. Moreover, in mice receiving NES + Estradiol (E2) co-treatment, levels of Olig2, Myt1, and Sox17 proteins did not change as compared to NES alone. Conclusion NES alone or with E2 increased the levels of transcription factors, essential for myelin synthesis.
Michel AO, Bendet A, Cheleuitte-Nieves C, Yarmohammadi H, Nurili F, Monette S, Michel AO, Bendet A, Basturk O, Askan G, Cheleuitte-Nieves C, Yarmohammadi H, Maxwell AWP, Ziv E, Schachtschneider KM, Gaba RC, Schook LB, Solomon SB, Boas FE
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Transarterial Embolization of Liver Cancer in a Transgenic Pig Model

JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY 2021 APR; 32(4):510-+
Purpose: To develop and characterize a porcine model of liver cancer that could be used to test new locoregional therapies. Materials and Methods: Liver tumors were induced in 18 Oncopigs (transgenic pigs with Cre-inducible TP53R167H and KRASG12D mutations) by using an adenoviral vector encoding the Cre-recombinase gene. The resulting 60 tumors were characterized on multiphase contrast-enhanced CT, angiography, perfusion, micro-CT, and necropsy. Transarterial embolization was performed using 40?120 ?m (4 pigs) or 100?300 ?m (4 pigs) Embosphere microspheres. Response to embolization was evaluated on imaging. Complications were determined based on daily clinical evaluation, laboratory results, imaging, and necropsy. Results: Liver tumors developed at 60/70 (86%) inoculated sites. Mean tumor size was 2.1 cm (range, 0.3?4 cm) at 1 week. Microscopically, all animals developed poorly differentiated to undifferentiated carcinomas accompanied by a major inflammatory component, which resembled undifferentiated carcinomas of the human pancreatobiliary tract. Cytokeratin and vimentin expression confirmed epithelioid and mesenchymal differentiation, respectively. Lymph node, lung, and peritoneal metastases were seen in some cases. On multiphase CT, all tumors had a hypovascular center, and 17/60 (28%) had a hypervascular rim. After transarterial embolization, noncontrast CT showed retained contrast medium in the tumors. Follow-up contrast-enhanced scan showed reduced size of tumors after embolization using either 40?120 ?m or 100?300 ?m Embosphere microspheres, while untreated tumors showed continued growth. Conclusions: Liver tumors can be induced in a transgenic pig and can be successfully treated using bland embolization.
Islam MS, Yang XW, Euler CW, Han XQ, Liu JH, Hossen I, Zhou Y, Li JQ
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Application of a novel phage ZPAH7 for controlling multidrug-resistant Aeromonas hydrophila on lettuce and reducing biofilms

FOOD CONTROL 2021 APR; 122(?):? Article 107785
Aeromonas hydrophila is an important pathogenic bacterium that causes foodborne illness worldwide. In this study, virulent phages from the sediment of a fish farm were propagated and isolated on a multidrug-resistant strain of A. hydrophila, ZYAH75. One phage, designated as ZPAH7, featured a unique turbid halo around a clear plaque on the bacterial lawn (indicative of potential depolymerase activity), and was selected for further analysis. ZPAH7 was classified as podophage by morphological and genomic methods. Further comparisons of genome nucleotide similarity, ratios of homologous proteins and phylogenetic relatedness among the terminase large subunit and major capsid proteins of similar phage deposited in GENBANK, led us to propose a new genus, ZPAH7virus, in the Autographivirinae subfamily of Podoviridae. ZPAH7 had an adsorption rate of 79% in 5 min, an eclipse period of 15 min, a latent period of 25 min, and a burst size of 148 +/- 9 PFU/cell. Antimicrobial application experiments showed that ZPAH7 lead to significantly reduction on A. hydrophila on lettuce. Additionally, ZPAH7 was able to inhibit biofilm formation, as well as degrade and kill bacteria in established biofilms. Furthermore, lytic activity of ZPAH7 remained stable across a wide range of temperatures and pH measurements. These results suggest ZPAH7 could be used as a potential biological control agent against A. hydrophila on food and/or biofilms on food contact surfaces.
Seidel E, Schewe J, Zhang JH, Dinh HA, Forslund SK, Marko L, Hellmig N, Peters J, Muller DN, Lifton RP, Nottoli T, Stolting G, Scholl UI
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Enhanced Ca2+ signaling, mild primary aldosteronism, and hypertension in a familial hyperaldosteronism mouse model (Cacna1h(M1560V/+))

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2021 APR 27; 118(17):? Article e2014876118
Gain-of-function mutations in the CACNA1H gene (encoding the T-type calcium channel Ca(V)3.2) cause autosomal-dominant familial hyperaldosteronism type IV (FH-IV) and early-onset hypertension in humans. We used CRISPR/Cas9 to generate Cacna1h(M1560V/+) knockin mice as a model of the most common FH-IV mutation, along with corresponding knockout mice (Cacna1h(-/-)). Adrenal morphology of both Cacna1h(M1560V/+) and Cacna1h(-/-) mice was normal. Cacna1h(M1560V/+) mice had elevated aldosterone:renin ratios (a screening parameter for primary aldosteronism). Their adrenal Cyp11b2 (aldosterone synthase) expression was increased and remained elevated on a high-salt diet (relative autonomy, characteristic of primary aldosteronism), but plasma aldosterone was only elevated in male animals. The systolic blood pressure of Cacna1h(M1560V/+) mice was 8 mmHg higher than in wild-type littermates and remained elevated on a high-salt diet. Cacna1h(-/-) mice had elevated renal Ren1 (renin-1) expression but normal adrenal Cyp11b2 levels, suggesting that in the absence of Ca(V)3.2, stimulation of the renin-angiotensin system activates alternative calcium entry pathways to maintain normal aldosterone production. On a cellular level, Cacna1h(M1560V/+) adrenal slices showed increased baseline and peak intracellular calcium concentrations in the zona glomerulosa compared to controls, but the frequency of calcium spikes did not rise. We conclude that FH-IV, on a molecular level, is caused by elevated intracellular Ca2+ concentrations as a signal for aldosterone production in adrenal glomerulosa cells. We demonstrate that a germline Cacna1h gain-of-function mutation is sufficient to cause mild primary aldosteronism, whereas loss of Ca(V)3.2 channel function can be compensated for in a chronic setting.
Maguin P, Marraffini LA
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From the discovery of DNA to current tools for DNA editing

JOURNAL OF EXPERIMENTAL MEDICINE 2021 APR 5; 218(4):? Article e20201791
In 1944, the Journal of Experimental Medicine published the groundbreaking discovery that DNA is the molecule holding genetic information (1944. J. Exp. Med. https://doi.org/10.1084/jem.79.2.137). This seminal finding was the genesis of molecular biology and the beginning of an incredible journey to understand, read, and manipulate the genetic code.
He H, Del Duca E, Diaz A, Kim HJ, Gay-Mimbrera J, Zhang N, Wu JN, Beaziz J, Estrada Y, Krueger JG, Pavel AB, Ruano J, Guttman-Yassky E
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Mild atopic dermatitis lacks systemic inflammation and shows reduced nonlesional skin abnormalities

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY 2021 APR; 147(4):1369-1380
Background: Molecular studies in atopic dermatitis (AD) are largely restricted to patients with moderate-to-severe disease. Objective: Our aim was to evaluate skin and blood abnormalities in mild, moderate, and severe AD. Methods: Skin and blood samples were obtained from 61 patients with AD (20 with mild or limited disease, 17 with moderate disease, and 24 with severe disease) and 20 healthy subjects. Immune and barrier markers were measured in lesional, nonlesional, and healthy skin by quantitative real-time PCR and immunohistochemistry, and in blood by using the OLINK proteomic assay. Results: Cellular markers of epidermal hyperplasia and T-cell/dendritic cell infiltration were increased in AD tissues of all patients in all severity groups versus in those of controls, whereas downstream T(H)2 cell-, T(H)22 cell-, T(H)1 cell-, and T(H)17 cell-related mediators demonstrated incremental elevations with increasing disease severity, in both lesional and nonlesional skin. Whereas the levels of the T(H)2 (IL13, CCL17, and CCL26) and T(H)22 (IL-22) cytokines were significantly elevated in both AD lesional and nonlesional skin of all patients regardless of the severity of their disease, patients with mild or limited AD showed increases in their levels of T(H)1 cell (IFNG, CXCL9, and CXCL10) and T(H)17 cell (IL-17A, CCL20, and CXCL1) markers in lesional but not nonlesional skin. Regulatory T-cell-related mediators (IL-10 and FOXP3) were comparably upregulated in all groups, without displaying the severity-based gradient in other immune axes. Unsupervised clustering aligned samples along a severity spectrum, where nonlesional mild or limited AD skin clustered with the samples from healthy controls. Furthermore, whereas the blood profiles of patients with moderate and severe AD showed gradual increases in the levels of T(H)1 cell-, T(H)2 cell-, and T(H)17 cell-related and atherosclerosis and/or cardiovascular risk (CCL7, FGF21, and IGFBP1) proteins, the blood profiles of patients with mild or limited AD lacked significant differences from those of the controls. Conclusion: Mild and limited AD show high levels of T(H)2/T(H)22 cell activation that is primarily localized to skin lesions and lacks the systemic inflammation of moderate and severe disease.