Gene silencing in HIV-1 latency by polycomb repressive group

<p>Abstract</p> <p>Background</p> <p>The persistence of latently Human immunodeficiency virus-1 (HIV-1) infected cellular reservoirs in resting CD4⁺T cells is a major obstacle to HIV-1 eradication. The detailed mechanism of HIV-1 latency remains unclear. We investigated histones and their post-translational modification associated with HIV-1 latency in novel HIV-1 latently infected cell lines established previously, NCHA cells.</p> <p>Methods</p> <p>To examine histones and their modification linked with HIV-1 latency, the expression profiles for core histone proteins and histone deacetylases (HDACs) in NCHA cells were characterized by RT-PCR, ELISA, and western blot. The levels of histone acetylation and methylation at histone H3 Lys⁹(H3K9) and Lys²⁷(H3K27) in HIV-1 latently infected cells were analyzed by western blot and chromatin immunoprecipitation-sequencing (ChIP-seq).</p> <p>Results</p> <p>The expression levels for four core histone proteins (H2A, H2B, H3 and H4) and HDACs (HDAC1-8) in NCHA cells were not significantly different from those in their parental cells. Histone H3K9 and H3K27 acetylations in NCHA cells showed no difference in parental and NCHA cells, whereas the levels of di- and tri-methylation were increased in NCHA cells. The expression of EED which is a component of polycomb repressive complex 2 (PRC2), and BMI1 and RING2 which are constituents of PRC1, were upregulated in NCHA cells. In addition, more ubiquitylation at histone H2A was detected in NCHA cells.</p> <p>Conclusions</p> <p>Our results suggest that tri-methylation of histone H3K27 and H2A ubiquitylation via polycomb group protein may play a crucial role in epigenetic silencing accounting for HIV-1 latency in NCHA cells.</p

Comparative study of the treatment outcomes of osteoporotic compression fractures without neurologic injury using a rigid brace, a soft brace, and no brace : a prospective randomized controlled non-inferiority trial

BACKGROUND:The efficacy of brace application for the treatment of osteoporotic compression fractures remains unclear. The purpose of this study was to compare the treatment outcomes in patients with osteoporotic compression fractures with regard to whether the patients had no braces, rigid braces, or soft braces.METHODS:We randomly assigned sixty patients with acute one-level osteoporotic compression fractures within three days of injury to the no-brace, soft-brace, and rigid-brace groups through 1:1:1 allocation. The primary outcome was the baseline adjusted Oswestry Disability Index score at twelve weeks after compression fracture. The non-inferior margin of the Oswestry Disability Index was set at an average of 10 points.RESULTS:The baseline adjusted Oswestry Disability Index score at twelve weeks after compression fracture in the no-brace group was not inferior to that in the soft-brace or rigid-brace groups. The mean adjusted Oswestry Disability Index score was 35.95 points (95% confidence interval, 25.42 to 46.47 points) in the no-brace group and 37.83 points (95% confidence interval, 26.77 to 48.90 points) in the soft-brace group, with a difference of -1.88 points (95% confidence interval, -7.02 to 9.38 points) between the groups. Similarly, the mean adjusted Oswestry Disability Index score was 35.95 points (95% confidence interval, 25.42 to 46.47 points) in the no-brace group and 33.54 points (95% confidence interval, 23.79 to 43.29 points) in the rigid-brace group, with a difference of 2.41 points (95% confidence interval, -7.86 to 9.27 points) between the groups. During the follow-up assessment period, there was no significant difference among the groups for the overall Oswestry Disability Index scores (p = 0.260), visual analog scale for pain scores for back pain (p = 0.292), and anterior body compression ratios (p = 0.237). However, the Oswestry Disability Index scores and the visual analog scale scores for back pain significantly improved with time after the fractures (p < 0.001), and the body compression ratios significantly decreased with time in all three groups (p < 0.001).CONCLUSIONS:The Oswestry Disability Index scores for the treatment of compression fractures without a brace were not inferior to those with soft or rigid braces. Moreover, the improvement in back pain and progression of anterior body compression were similar among the three groups.OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000004226/15SEQ:15PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000004226ADJUST_YN:NEMP_ID:A079510DEPT_CD:801CITE_RATE:4.309DEPT_NM:의학과SCOPUS_YN:NCONFIRM:

Ecological connectivity analysis based on the fish community in Jeongan Stream

This study focused on the longitudinal connectivity analysis, based on fish communities in the aspect of spatial variations of 34 sites from upstream to downstream. The Fish Assessment Index (FAI), based on ecological guilds and species composition, was applied to compare the ecological health among the sampling sites. The total number of 35 fish species, were sampled during the study period with dominant species of Zacco platypus (35.4%) and Zacco koreanus (11.8%). Cluster analysis showed that all sites were categorized as 4 distinct group communities (A, B, C, D). Non-metric multidimensional scaling analysis showed distinct difference between upstream (A, B) and downstream groups (C, D). Indicator Value Analysis (IndVal method), conducted to identify indicator species within each group, indicated that the species favoring upstream environments Rhynchocypris oxycephalus for the Group A and Iksookimia koreensis for the Group B. In contrast, the analysis indicated that the species with a preference for downstream habitats Pseudogobio esocinus for the Group C and Carassius auratus for the Group D. Ecological health, based on the FAI scores, showed a declining pattern toward the downstream, along with an increasing proportion of tolerant species and omnivores within the fish community. Overall these findings suggest the compositions of fish communities, as four groups, were modified by the weir structures and organic matter, nutrient pollutions

Platinum encapsulated within a bacterial nanocellulosic–graphene nanosandwich as a durable thin-film fuel cell catalyst

Developing cost-effective electrocatalysts for proton electrolyte membrane fuel cell electrodes has proven challenging because of the difficulty in finding inexpensive alternatives to platinum that are as catalytically active. A more straightforward approach is to minimize the cost of using platinum by reducing its mass while preserving its active area, that is, by reducing the nanoparticle diameter. However, smaller nanoparticles are especially vulnerable to loss via dissolution and ripening. Here, we combat this degradation by preparing a hybrid graphene–nanocellulose sandwich to securely encapsulate platinum catalysts in a robust and conductive envelope. This securely anchors the nanoparticles, preventing the loss of active area through ripening or detachment. Our nanocellulose hybrid was prepared via the facile and scalable carbonization of a bacterial cellulose feedstock, yielding a high-surface-area, robust, and conductive catalyst support. Cyclic voltammetry and transmission electron microscopy reveal that the graphene–nanocellulose composite significantly reduces the effective surface area losses of ultrafine (<3 nm diameter) nanoparticle catalysts, primarily by preventing Ostwald ripening and dissolution

Is there an association between vitamin D deficiency and adenotonsillar hypertrophy in children with sleep-disordered breathing?

Abstract Background Low vitamin D levels have been linked to the risk of sleep-disordered breathing (SDB) in children. Although adenotonsillar hypertrophy (ATH) is the major contributor to childhood SDB, the relationship between ATH and serum vitamin D is uncertain. We therefore investigated the relationship between vitamin D levels and associated factors in children with ATH. Methods We reviewed data from all children with SDB symptoms who were treated from December 2013 to February 2014. Of these, 88 children whose serum vitamin D levels were measured were enrolled in the study. We divided the children into four groups based on adenoidal and/or tonsillar hypertrophy. We conducted a retrospective chart review to analyze demographic data, the sizes of tonsils and adenoids, serum 25-hydroxy-vitamin D [25(OH)D] level, body mass index (BMI), and allergen sensitization patterns. Results Children in the ATH group had a lower mean 25(OH)D level than did those in the control group (p < 0.05). Children with vitamin D deficiencies exhibited markedly higher frequencies of adenoidal and/or tonsillar hypertrophy than did those with sufficient vitamin D (p < 0.05). Spearman’s correlation analysis identified an inverse correlation between serum 25(OH)D levels and age, tonsil and adenoid size, and height (all p < 0.05). In a multiple regression analysis, tonsil and adenoid size as well as BMI-z score, were associated with 25(OH)D levels after controlling for age, sex, height, and mite sensitization (p < 0.05). Conclusions Our results suggest that low vitamin D levels are linked to ATH. Both the sizes of the adenoids and tonsils and the BMI-z score were associated with the 25(OH)D level. Therefore, measurement of the serum 25(OH)D level should be considered in children with ATH and SDB symptoms

Reproductive Cycle and Sexual Group Maturity of <i>Buccinum osagawai</i> (Neogastropoda: Buccinidae)

This study was performed to obtain information on the basic reproductive ecology and biological resource management of Buccinum osagawai. Samples were collected from August 2018 to October 2019 with a drum-shaped net at a depth of 150–250 m along the continental shelf in Jumunjin, on the east coast of Korea. The species showed gonochorism and a lack of external sexual dimorphism. The overall sex ratio (F:M) was 1:1.2 (n = 549, F = 250, M = 299); as the size of the individuals increased, the proportion of males tended to decrease. The development pattern of the oocyte was synchronous, in which a dominant group of oocytes was identified within the same ovary. The size of the ripe oocyte was 82.3 (±22.6) × 125.5 (±22.0) μm. The spermatocyte development pattern was group-synchronous, in which multiple stages of germ cell populations were simultaneously identified within the same spermatogenic acinus. The gonad index (GI) for both males and females showed the highest value during June, after which it decreased sharply, and after August it was below 2.0. The main spawning season was from June to July, and the GI and stages of gonadal development did not show a pattern of seasonal changes. The main gonadal active season was from May to July, and both male and female gonadal development and maturation took place over a short period, whereas the recovery period after spawning was longer. At least 60.5% of the group, considering both males and females, showed maturity at 50.1 mm SH or more. Furthermore, the size of 50% group maturity was shown at approximately 50.0 mm SH

In-situ scanning tunneling microscopy observation of thickness-dependent air-sensitive layered materials and heterodevices

© 2022, The Korean Physical Society.Quasi-two-dimensional (Quasi-2D) van der Waals (vdW) materials can be mechanically or chemically exfoliated down to monolayer because of their strong intralayer bonding and the weak interlayer vdW interaction. Thanks to this unique property, one can often find exotic thickness-dependent electronic properties from these quasi-2D vdW materials, which can lead to bandgap opening, emerging superconductivity, or enhanced charge density waves with decreasing thickness. Surface-sensitive scanning tunneling microscopy (STM) can provide direct observation of structural and electronic characteristics of such layered materials with atomic precision in real space. However, it is very challenging to preserve the intrinsic surfaces of air-sensitive quasi-2D materials between preparation and measurement. In addition, vdW 2D crystals after exfoliation are extremely hard to explore with a typical STM setup due to their small size (≤ 10 μm). Here, we present a straightforward method compatible with any STM setup having optical access: (1) exfoliating and/or stacking layered materials in a glove box, (2) transferring them to an ultra-high vacuum STM chamber using a suitcase without exposure to air, and (3) navigating surface to locate exfoliated vdW 2D flakes with different thicknesses. We successfully demonstrated that the clean surfaces of the air-sensitive Fe 3GeTe 2 can be effectively protected from unwanted oxidation during transfer. Furthermore, our method provides a simple but useful way to access a specific tiny stack of layered materials without any ex-situ fabrication processes for STM navigation. Our experimental improvement will open up a new way to investigate air-sensitive layered vdW materials with various thicknesses via surface-sensitive techniques including STM.11Nsciescopuskc