86 research outputs found

    Species-Specific Expansion and Molecular Evolution of the 3-hydroxy-3-methylglutaryl Coenzyme A Reductase (HMGR) Gene Family in Plants

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    Kazakh dandelion (Taraxacum kok-saghyz, Tk) is a rubber-producing plant currently being investigated as a source of natural rubber for industrial applications. Like many other isoprenoids, rubber is a downstream product of the mevalonate pathway. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) enzyme catalyzes the conversion of 3-hydroxy-3-methylglutaryl-CoA to mevalonic acid, a key regulatory step in the MVA pathway. Such regulated steps provide targets for increases in isoprenoid and rubber contents via genetic engineering to increase enzyme activities. In this study, we identify a TkHMGR1 gene that is highly expressed in the roots of Kazakh dandelion, the main tissue where rubber is synthesized and stored. This finding paves the way for further molecular and genetic studies of the TkHMGR1 gene, and its role in rubber biosynthesis in Tk and other rubber-producing plants

    Systematic Identification of Novel, Essential Host Genes Affecting Bromovirus RNA Replication

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    Positive-strand RNA virus replication involves viral proteins and cellular proteins at nearly every replication step. Brome mosaic virus (BMV) is a well-established model for dissecting virus-host interactions and is one of very few viruses whose RNA replication, gene expression and encapsidation have been reproduced in the yeast Saccharomyces cerevisiae. Previously, our laboratory identified ∼100 non-essential host genes whose loss inhibited or enhanced BMV replication at least 3-fold. However, our isolation of additional BMV-modulating host genes by classical genetics and other results underscore that genes essential for cell growth also contribute to BMV RNA replication at a frequency that may be greater than that of non-essential genes. To systematically identify novel, essential host genes affecting BMV RNA replication, we tested a collection of ∼900 yeast strains, each with a single essential gene promoter replaced by a doxycycline-repressible promoter, allowing repression of gene expression by adding doxycycline to the growth medium. Using this strain array of ∼81% of essential yeast genes, we identified 24 essential host genes whose depleted expression reproducibly inhibited or enhanced BMV RNA replication. Relevant host genes are involved in ribosome biosynthesis, cell cycle regulation and protein homeostasis, among other cellular processes. BMV 2aPol levels were significantly increased in strains depleted for a heat shock protein (HSF1) or proteasome components (PRE1 and RPT6), suggesting these genes may affect BMV RNA replication by directly or indirectly modulating 2aPol localization, post-translational modification or interacting partners. Investigating the diverse functions of these newly identified essential host genes should advance our understanding of BMV-host interactions and normal cellular pathways, and suggest new modes of virus control

    Research Progress in Machining Technology of Nanohole Arrays

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    Focused Ion Beam Milling of Single-Crystal Sapphire with A-, C-, and M-Orientations

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    Sapphire substrates with different crystal orientations are widely used in optoelectronic applications. In this work, focused ion beam (FIB) milling of single-crystal sapphire with A-, C-, and M-orientations was performed. The material removal rate (MRR) and surface roughness (Sa) of sapphire with the three crystal orientations after FIB etching were derived. The experimental results show that: The MRR of A-plane sapphire is slightly higher than that of C-plane and M-plane sapphires; the Sa of A-plane sapphire after FIB treatment is the smallest among the three different crystal orientations. These results imply that A-plane sapphire allows easier material removal during FIB milling compared with C-plane and M-plane sapphires. Moreover, the surface quality of A-plane sapphire after FIB milling is better than that of C-plane and M-plane sapphires. The theoretical calculation results show that the removal energy of aluminum ions and oxygen ions per square nanometer on the outermost surface of A-plane sapphire is the smallest. This also implies that material is more easily removed from the surface of A-plane sapphire than the surface of C-plane and M-plane sapphires by FIB milling. In addition, it is also found that higher MRR leads to lower Sa and better surface quality of sapphire for FIB etching

    Enhanced Microsphere-Assisted Picosecond Laser Processing for Nanohole Fabrication on Silicon via Thin Gold Coating

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    The nanohole arrays on the silicon substrate can effectively enhance the light absorption in thin film silicon solar cells. In order to optimize the solar energy absorption, polystyrene microspheres with diameters of 1 μm are used to assist picosecond laser with a wavelength of 1064 nm to fabricate nanohole arrays on silicon substrate. The experimental results show that the morphology and size of the silicon nanoholes strongly depend on the laser fluence. At 1.19–1.59 J/cm2 laser fluences, well-ordered arrays of nanoholes were fabricated on silicon substrate, with diameters domain from 250 to 549 nm and depths ranging from 60 to 99 nm. However, large amounts of sputtered nanoparticles appeared around the silicon nanoholes. To improve the surface morphology of silicon nanoholes, a nanolayered gold coating is applied on silicon surface to assist laser processing. The results show that, for gold-coated silicon substrate, sputtered nanoparticles around the nanoholes are almost invisible and the cross-sectional profiles of the nanoholes are smoother. Moreover, the ablation rate of the nanoholes on the gold-coated silicon substrate have increased compared to that of the nanoholes on the uncoated one. This simple method allows fast fabrication of well-ordered nanoholes on silicon substrate without sputtered nanoparticles and with smooth inner surface

    Pregnancy outcomes following ultrasound-guided high-intensity focused ultrasound in submucous leiomyomas: a retrospective study

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    AbstractObjective To investigate the impact of ultrasound-guided high-intensity focused ultrasound (USgHIFU) on pregnancy in submucous leiomyomas.Materials and methods Between October 2015 and October 2021, a retrospective observational study was conducted at the Affiliated Hospital of North Sichuan Medical College, China, for 32 women with submucous leiomyomas who became pregnant after USgHIFU. Pregnancy outcomes, submucous leiomyomas characteristics, and USgHIFU parameters were analyzed.Results A total of 17 (53.1%) deliveries were successfully achieved, with full-term delivery in 16 (94.1%) patients and preterm delivery in 1 (5.9%). After USgHIFU, the effective volume in the uterus cavity and the volume of submucous leiomyomas shrank in all 32 patients. The median time to achieve pregnancy after USgHIFU was 11.0 months. Before pregnancy, myoma type was downgraded in 13 (40.6%) patients, stable in 10 (31.3%) and upgraded in 9 (28.1%). The vaginal expulsion rate of submucous leiomyomas was 28.1%, with complete expulsion in 3 (9.4%) patients and partial expulsion in 6 (18.8%). After USgHIFU, the size of submucous leiomyomas did not increase in each trimester (all p > 0.05). The high complications rate during pregnancy (7/17, 41.2%) was associated with advanced maternal age, with only one (5.9%) premature rupture of membranes possibly associated with submucous leiomyomas. There were 6 (35.5%) vaginal delivery and 11 (64.7%) cesarean sections. All 17 newborns developed well, with a mean birth weight of 3482 g.Conclusions In patients with submucous leiomyomas, pregnancies and full-term deliveries can be successfully achieved following USgHIFU, with few related complications

    The complete chloroplast genome of Bupleurum marginatum var. stenophyllum (H. Wolff) Shan & Yin Li (Apiaceae), a new substitution for Chinese medicinal material, Bupleuri Radix (Chai hu)

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    The root of Bupleurum marginatum var. stenophyllum (H. Wolff) Shan & Yin Li (Apiaceae), a new substitution for the popular Chinese medicinal material, Bupleuri Radix (Chai hu), is not easily distinguishable via traditional methods. The complete chloroplast genome sequence of B. marginatum var. stenophyllum was characterized using next-generation sequencing and the de novo assembly method. The complete genome was 155,576 bp in length and contained two inverted repeat (IR) regions of 26,311 bp, a large single-copy (LSC) region of 85,351 bp, and a small single-copy (SSC) region of 17,603 bp. It encoded 113 unique genes consisting of 79 protein-coding genes (PCGs), 30 transfer RNA genes, and four ribosomal RNA genes. Importantly, three genes (petB, petD and rps16) with small exon, and one trans-splicing gene (rps12) were correctly annotated. The overall GC content of the B. marginatum var. stenophyllum chloroplast genome is 37.7%. The phylogenetic analyses indicated that B. marginatum var. stenophyllum was closely related to B. marginatum. Moreover, many genetic information sites were available for distinguishing B. marginatum var. stenophyllum from the official ‘Chai hu’ plant sources, B. scorzonerifolium Willd. and B. chinense DC

    Gender-Specific Health-Adjusted Life Expectancy of Type 2 Diabetes Mellitus Among the Rural Elderly Population

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    Objectives: This study aimed to estimate the life expectancy (LE) and health-adjusted life expectancy (HALE) of type 2 diabetes mellitus (T2DM) among the rural elderly population.Methods: A total of 10,318 participants aged 65 to 79 were derived from the Henan Rural Cohort. The LE and HALE were calculated via the Sullivan method and multistate life table.Results: Among 10,318 subjects, 1,325 suffered from T2DM at the baseline, and 394 participants had newly-developed T2DM. The results from the Sullivan method showed that the LE, HALE, and HALE/LE were 17.98, 16.18 years, and 89.95% for men aged 65 to 69, and the corresponding estimates for women were 21.81, 18.73 years, and 85.86%, respectively. The LE, HALE and HALE/LE calculated via multistate life table were 19.86, 17.53 years, and 88.29% for men at aged 65, and the corresponding values for women were 25.01, 20.87 years, and 83.44%, respectively.Conclusion: Rural elderly women have a longer LE and HALE of T2DM, but they have lower quality of life than men. More attention should be paid to T2DM among rural elderly people, especially in women.Clinical Trial Registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375
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