1,721,236 research outputs found
FIGURE 2 in Heteroconium tulsiense (Antennulariellaceae): a novel microfungus from Sanjay Gandhi National Park, Maharashtra, India
No full textFIGURE 2. SEM Images of Heteroconium tulsiense sp. nov. A. Aggregated conidiophores attached to the host substratum; B. Septation in conidiophores, C, D. Conidial chain having 4 conidia; E. Conidia with narrow apical end and broad truncate base, F. Ends of conidia. Scale bars: A, C, D = 20 µm, B, F = 2 µm, E = 10 µm.Published as part of Dubey, Rashmi & Pandey, Amit D., 2022, Heteroconium tulsiense (Antennulariellaceae): a novel microfungus from Sanjay Gandhi National Park, Maharashtra, India, pp. 190-196 in Phytotaxa 536 (2) on page 193, DOI: 10.11646/phytotaxa.536.2.8, http://zenodo.org/record/625768
Clinical and biochemical consequences of p450 oxidoreductase deficiency
No full textPatients with P450 oxidoreductase (POR) deficiency typically present with adrenal insufficiency, genital anomalies and bony malformations resembling the Antley-Bixler craniosynostosis syndrome. Since our first report in 2004, more than 40 POR mutations have been identified in over 65 patients. POR is the obligate electron donor to all microsomal P450 enzymes, including the steroidogenic enzymes CYP17A1, CYP21A2 and CYP19A1. POR deficiency may cause disordered sexual development manifested as genital undervirilization in 46, XY newborns as well as overvirilization in those who are 46, XX. This may be explained by impaired aromatization of fetal androgens that may cause maternal virilization and low urinary estriol levels during pregnancy. In addition, the alternate 'backdoor' pathway of androgen biosynthesis, which leads to dihydrotestosterone production bypassing androstenedione and testosterone, may also play a role. Functional assays studying the effects of POR mutations on steroidogenesis showed that several POR variants impaired CYP17A1, CYP21A2 and CYP19A1 activities to different degrees, indicating that each POR variant must be studied separately for each potential target P450 enzyme. POR variants may also affect skeletal development and drug metabolism. As most drugs are metabolized by hepatic microsomal P450 enzymes, studies of the impact of POR mutations on drug-metabolizing P450s are particularly important
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect of CYP17A1 17, 20 Lyase Inhibitors on Regulation of Adrenal Androgen Biosynthesis
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Heteroconium tulsiense Rashmi Dubey 2022, sp. nov.
No full text<i>Heteroconium tulsiense</i> Rashmi Dubey <i>sp. nov.</i> (Figs 1, 2) <p> <i>Mycobank</i> MB-839843</p> <p> <b>Etymology</b>:—Named after place of collection, Tulsi Range of Sanjay Gandhi National Park, Maharashtra, India.</p> <p> <b>Holotype</b>:— INDIA. Maharashtra: Mumbai, Sanjay Gandhi National Park, Tulsi Range, Tiger Reserve areas, on dry twig litter, 22 January 2017, Rashmi Dubey, BSI (WC) 209274, deposited in herbarium of Botanical Survey of India, Western Regional Centre, Pune, Maharashtra, India.</p> <p> <b>Description:—</b> Colonies on natural substrate, effuse, hairy. Mycelium superficial and immersed, composed of septate, smooth-walled, dark brown or brown hyphae, 1–2 μm diam. Conidiophores macronematous, mononematous, simple, erect, mostly unbranched but aggregated near the base, straight or slightly flexuous, cylindrical, smooth, thickwalled, 3–9-septate, brown to dark brown, 33–62 × 7–9 μm. Conidiogenous cells monoblastic, terminal, cylindrical, integrated, determinate or percurrent, brown, smooth, truncate at the apex, 5–9 × 5.75–7.0 μm. Conidial secession schizolytic. Conidia holoblastic, acrogenous, blastocatenate in chains of up to four, smooth, obclavate, brown, unevenly pigmented, pale brown ends, rounded at apex, truncate at base, thick-walled, 31–45 × 7.5–8.7 μm, 4–7-septate, slightly constricted at the septa.</p> <p> <b>Known distribution:—</b> Only known from type locality in the Sanjay Gandhi National Park, Maharashtra, India.</p>Published as part of <i>Dubey, Rashmi & Pandey, Amit D., 2022, Heteroconium tulsiense (Antennulariellaceae): a novel microfungus from Sanjay Gandhi National Park, Maharashtra, India, pp. 190-196 in Phytotaxa 536 (2)</i> on page 192, DOI: 10.11646/phytotaxa.536.2.8, <a href="http://zenodo.org/record/6257685">http://zenodo.org/record/6257685</a>
NADPH P450 oxidoreductase: structure, function, and pathology of diseases
No full textCytochrome P450 oxidoreductase (POR) is an enzyme that is essential for multiple metabolic processes, chiefly among them are reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs and xenobiotics. Mutations in POR cause a complex set of disorders that often resemble defects in steroid metabolizing enzymes 17α-hydroxylase, 21-hydroxylase and aromatase. Since our initial reports of POR mutations in 2004, more than 200 different mutations and polymorphisms in POR gene have been identified. Several missense variations in POR have been tested for their effect on activities of multiple steroid and drug metabolizing P450 proteins. Mutations in POR may have variable effects on different P450 partner proteins depending on the location of the mutation. The POR mutations that disrupt the binding of co-factors have negative impact on all partner proteins, while mutations causing subtle structural changes may lead to altered interaction with specific partner proteins and the overall effect may be different for each partner. This review summarizes the recent discoveries related to mutations and polymorphisms in POR and discusses these mutations in the context of historical developments in the discovery and characterization of POR as an electron transfer protein. The review is focused on the structural, enzymatic and clinical implications of the mutations linked to newly identified disorders in humans, now categorized as POR deficiency
Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia
Full text linkCongenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH
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