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1.
J Synchrotron Radiat ; 31(Pt 4): 877-887, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38771778

RESUMEN

Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X-ray microscopy (STXM) is combined with X-ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single-crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X-ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale.

2.
Photochem Photobiol Sci ; 23(8): 1533-1542, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39030314

RESUMEN

Removal of organic dyes like methylene blue (MB) from industrial effluents serves as potential source of potable water. Photocatalytic degradation using sustainable catalyst is deemed to be an affordable solution. In this work, Nd2O3/MgO nanocomposite with different compositions (1, 3, and 5wt% Nd2O3 with MgO) have been achieved using hydrothermal synthesis and characterized extensively. Interestingly, increasing Nd2O3 proportion (1-5%) enhances light absorption, and decreases band gap and electron-hole recombination. The efficacy of the photocatalysts is tested with the degradation of MB dye, through optimizing Nd2O3/MgO proportion, contact time, catalyst dose, and pH. Interestingly, control experiments reveal that 5wt% Nd2O3/MgO achieve 99.6% degradation of MB in 90 min at pH 7, compared to 88.8% with bare MgO under same condition. Kinetic data show that 5wt% Nd2O3/MgO exhibits ca. 3 times higher degradation rate compared to MgO. For the first time, our work enable MgO-based sustainable photocatalyst development with minimum (5 wt%) rare-earth combination to achieve excellent photocatalytic degradation performance.

3.
Zoolog Sci ; 41(3): 257-262, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38809864

RESUMEN

The grey-headed lapwing (Vanellus cinereus) is a wading species in East Asia. However, examples of regional population dynamics and genetic research are limited. To reconsider the natural history and current status of the grey-headed lapwing in Japan, we analyzed the genetic diversity of the Japanese grey-headed lapwing population. We collected 77 grey-headed lapwing samples from 12 locations across Japan during the breeding season and three individuals during the wintering season and extracted DNA; 496-bp sequences of the ND2, which form part of the mitochondrial DNA, were determined for genetic analysis of the population. Consequently, 10 haplotypes were detected in 80 individuals, and 67 individuals, 84% of the total, shared two haplotypes, namely Vc1 and Vc2. Furthermore, the results showed that the prevalence of Vc1 was higher mainly in northern Japan, while that of Vc2 was higher mainly in southern Japan. Genetic diversity analysis showed that the overall haplotype diversity in Japan was 0.617, which is not particularly low. The sequence of Vc1 was exactly the same as that of grey-headed lapwing in China. Our study revealed the genetic structure of the grey-headed lapwing, suggesting that as the grey-headed lapwing expanded its distribution area into southern Japan, many Vc2-positive individuals migrated southward, resulting in a higher detection rate of Vc2 in southern Japan.


Asunto(s)
Charadriiformes , ADN Mitocondrial , Variación Genética , Animales , ADN Mitocondrial/genética , Haplotipos , Japón , Charadriiformes/genética
4.
Nano Lett ; 23(2): 550-557, 2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36633430

RESUMEN

Magnetic skyrmion and its derivatives have demonstrated fascinating topological behaviors with potential applications in future spintronic devices. Despite the recent progress, the spontaneous skyrmion lattice and successive topological transition in the magnets with easy-plane magnetic anisotropy are still elusive especially at room temperature. Here, in a centrosymmetric rhombohedral Nd2Co17 magnet with easy-plane magnetic anisotropy, spontaneous biskyrmions are observed over a wide temperature range across room temperature, and then evolve into enclosed in-plane domains with nanometric size due to the enhancement of the planar magnetic anisotropy. The spontaneous generation of the biskyrmion lattice and its evolution along different crystal orientations demonstrate the crucial role of intrinsic bi-anisotropy and demagnetization effects. This discovery provides a fundamental insight into the nature of topological magnetic textures in easy-plane anisotropy materials and suggests an arena to explore the topological states in rare-earth magnets as well as their applications in spintronics.

5.
Environ Res ; 219: 115140, 2023 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-36565846

RESUMEN

Abuse of carbendazim (CBZ) leaves excessive pesticide residues on agricultural products, which endangers human health because of the residues' high concentrations. Hence, a composite consisting of functionalized carbon nanofibers (f-CNF) with neodymium oxide (Nd2O3) was fabricated to monitor CBZ at trace levels. The Nd2O3/f-CNF composite-modified electrode displays higher electro-oxidation ability towards CBZ than Nd2O3 and f-CNF-modified electrodes. The combined unique properties of Nd2O3 and f-CNF result in a substantial specific surface area, superior structural stability, and excellent electrocatalytic activity of the composite yielding enhanced sensitivity to detecting CBZ with a detection limit of 4.3 nM. Also, the fabricated sensor electrode can detect CBZ in the linear concentration range of up to 243.0 µM with high selectivity, appropriate reproducibility, and stability. A demonstration of the sensing capability of CBZ in vegetables, water, and soil samples was reported paving the way for its use in practical applications.


Asunto(s)
Fungicidas Industriales , Nanofibras , Humanos , Carbono/química , Verduras , Agua , Reproducibilidad de los Resultados , Suelo
6.
Molecules ; 28(23)2023 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-38067647

RESUMEN

The synthesis of Nd-Fe-B magnetic powders via chemical techniques presents significant promise, but poses challenges due to their inherent chemical instability. In this investigation, Nd-Fe-B hard magnetic particles were synthesized utilizing an eco-friendly and simple microwave-assisted hydrothermal synthetic method. The technique involves the synthesis of the Nd-Fe-B oxide precursor using the microwave-assisted hydrothermal method, followed by reduction-diffusion using CaH2. The microwave-assisted hydrothermal technique presents a viable approach for preparing Nd-Fe-B precursor particles, offering advantages such as time and energy efficiency and environmental sustainability. The synthesized Nd-Fe-B particles demonstrated a coercivity of up to 2.3 kOe. These magnetic particles hold significant potential for use in high-performance permanent magnets, and can effectively contribute to developing high-energy density exchange-coupled nanocomposite magnets. This study also offers valuable insights into the design and synthesis of additional magnetic materials based on rare earth elements.

7.
J Synchrotron Radiat ; 29(Pt 1): 37-44, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34985421

RESUMEN

As potential nuclear waste host matrices, two series of uranium-doped Nd2Zr2O7 nanoparticles were successfully synthesized using an optimized molten salt method in an air atmosphere. Our combined X-ray diffraction, Raman and X-ray absorption fine-structure (XAFS) spectroscopy studies reveal that uranium ions can precisely substitute the Nd site to form an Nd2-xUxZr2O7+δ (0 ≤ x ≤ 0.2) system and the Zr site to form an Nd2Zr2-yUyO7+δ (0 ≤ y ≤ 0.4) system without any impurity phase. With increasing U concentration, there is a phase transition from pyrochlore (Fd3m) to defect fluorite (Fm3m) structures in both series of U-doped Nd2Zr2O7. The XAFS analysis indicates that uranium exists in the form of high-valent U6+ in all samples. To balance the extra charge for substituting Nd3+ or Zr4+ by U6+, additional oxygen is introduced accompanied by a large structural distortion; however, the Nd2Zr1.6U0.4O7+δ sample with high U loading (20 mol%) still maintains a regular fluorite structure, indicating the good solubility of the Nd2Zr2O7 host for uranium. This study is, to the best of our knowledge, the first systematic study on U-incorporated Nd2Zr2O7 synthesized via the molten salt method and provides convincing evidence for the feasibility of accurately immobilizing U at specific sites.

8.
Bull Exp Biol Med ; 172(4): 495-498, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35175481

RESUMEN

The measurement of the level of mitochondrial DNA (mtDNA) in the blood is a difficult problem due to high variability of mitochondrial genes, deletions in the mitochondrial genome in some pathological conditions, different sources of mtDNA into the bloodstream (mtDNA from tissues, from blood cells, etc.). We designed primers and TaqMan probes for highly conserved regions of the ND1 and ND2 genes outside the mitochondrial deletions "hot zones". For standardizing the technique, the true concentration of low-molecular-weight mtDNA was determined by real-time PCR for two targets: a fragment of the ND2 gene (122 bp) and the ND1 and ND2 genes (1198 bp). The sensitivity and specificity of the developed approach were verified on a DNA pool isolated from the blood plasma of healthy donors of various nationalities. The concentration of low-molecular-weight mtDNA in the blood plasma of two patients with COVID-19 was monitored over two weeks of inpatient treatment. A significant increase in the content of low-molecular-weight mtDNA was observed during the first 5 days after hospitalization, followed by a drop to the level of healthy donors. The developed technique makes it possible to assess the blood level of low-molecular-weight mtDNA regardless of the quality of sampling and makes it possible to standardize this biological marker in a wide range of infectious and non-infectious pathologies.


Asunto(s)
COVID-19/metabolismo , Ácidos Nucleicos Libres de Células/genética , ADN Mitocondrial/genética , NADH Deshidrogenasa/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Adulto , Anciano , COVID-19/virología , Estudios de Casos y Controles , Ácidos Nucleicos Libres de Células/sangre , Cartilla de ADN/síntesis química , ADN Mitocondrial/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mitocondrias/genética , Mitocondrias/virología , NADH Deshidrogenasa/sangre , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , SARS-CoV-2/patogenicidad
9.
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi ; 40(12): 881-887, 2022 Dec 20.
Artículo en Zh | MEDLINE | ID: mdl-36646477

RESUMEN

Objective: To explore the effects of Nd(2)O(3) exposure to rare earth particles on the secretion of sex hormones, cytochrome P450 family member 11A1 (CYP11A1) , spermatogenesis markers promyelocytic leukemia zinc finger protein (PLZF) and retinoic acid stimulating gene 8 (STRA8) protein in C57 BL/6J male mice. Methods: In March 2021, Forty-eight male C57 BL/6J mice aged 6-8 weeks divided into control group and Nd(2)O(3) exposure low, medium and high dose groups (exposing doses of 62.5, 125.0, 250.0 mg/ml Nd(2)O(3)) , 12 per group. The mice in the Nd(2)O(3) groups were perfused with different doses of Nd(2)O(3) suspension by a one-time non-exposing tracheal instillation method, and the control group was perfused with an equal volume of normal saline, with a volume of 0.1 ml, to establish a mouse reproductive function injury model. After 28 days of exposure, the mice's body weight, testes and epididymis were weighed, and the organ coefficients were calculated; the two epididymis were taken to make a sperm suspension to determine the sperm count, survival rate, and deformity rate; inductively coupled plasma mass spectrometry (ICP-MS) method was used to detect the content of Nd in mouse testis tissue; HE staining was used to detect testicular tissue pathological changes and quantitative analysis; enzyme-linked immunosorbent assay (ELISA) method was used to detect serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) and testosterone (T) content; western blot was used to detect the protein levels of CYP11A1, PLZF and STRA8 in testicular tissues. Results: Compared with the control group, with the increase of the exposure dose, the Nd content in the testis of the mice showed an increasing trend, the sperm survival rate and LH showed a decreasing trend, and the sperm deformity rate showed an increasing trend (P<0.05) ; Pathological showed that the number of sperm in the seminiferous tubules of the testicular tissue in the Nd(2)O(3) medium and high dose groups was significantly reduced, and the germinal epithelial disintegration, intraepithelial vacuolization, and exfoliation of spermatogenic cells and supporting cells occurred; The height of germinal epithelium was significantly reduced, and the percentage of damaged seminiferous tubules showed an increasing trend (P<0.05) ; FSH and T levels in serum in the middle and high dose groups of Nd(2)O(3), and CYP11A1, PLZF and STRA8 proteins in testicular tissues showed a downward trend with increasing dose (P<0.05) . Conclusion: The rare earth particulate Nd(2)O(3) may interfere with the expression of CYP11A1, PLZF and STRA8 protein, thereby causing the disorder of sex hormone secretion in the body, the maintenance of spermatogonia and the obstruction of the process of meiosis, causing reproductive function damage.


Asunto(s)
Enzima de Desdoblamiento de la Cadena Lateral del Colesterol , Neodimio , Semen , Animales , Masculino , Ratones , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Enzima de Desdoblamiento de la Cadena Lateral del Colesterol/metabolismo , Hormona Folículo Estimulante/metabolismo , Hormona Luteinizante/metabolismo , Proteína de la Leucemia Promielocítica con Dedos de Zinc/metabolismo , Semen/metabolismo , Recuento de Espermatozoides , Espermatogénesis , Testículo , Testosterona/metabolismo , Neodimio/toxicidad , Óxidos/toxicidad
10.
J Fish Biol ; 98(2): 577-582, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33090509

RESUMEN

We report 24 new records of the Brazilian cownose ray Rhinoptera brasiliensis outside its accepted geographic range. Sequencing of a 442-base pair portion of the mitochondrial NADH dehydrogenase subunit 2 gene for 282 Rhinoptera samples revealed eight records off the east coast of the USA and 16 from the eastern Gulf of Mexico. Both sexes of all life stages were documented in all seasons over multiple years in the Indian River and Lake Worth lagoons, Florida, indicating that their range extends further in the western North Atlantic than previously described.


Asunto(s)
Distribución Animal , NADH Deshidrogenasa/genética , Rajidae/genética , Animales , Océano Atlántico , Femenino , Florida , Golfo de México , Masculino , Ríos , Rajidae/clasificación
11.
Hum Mutat ; 41(8): 1394-1406, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32419253

RESUMEN

Whole mitochondrial DNA (mtDNA) sequencing is now systematically used in clinical laboratories to screen patients with a phenotype suggestive of mitochondrial disease. Next Generation Sequencing (NGS) has significantly increased the number of identified pathogenic mtDNA variants. Simultaneously, the number of variants of unknown significance (VUS) has increased even more, thus challenging their interpretation. Correct classification of the variants' pathogenicity is essential for optimal patient management, including treatment and genetic counseling. Here, we used single muscle fiber studies to characterize eight heteroplasmic mtDNA variants, among which were three novel variants. By applying the pathogenicity scoring system, we classified four variants as "definitely pathogenic" (m.590A>G, m.9166T>C, m.12293G>A, and m.15958A>T). Two variants remain "possibly pathogenic" (m.4327T>C and m.5672T>C) but should these be reported in a different family, they would be reclassified as "definitely pathogenic." We also illustrate the contribution of single-fiber studies to the diagnostic approach in patients harboring pathogenic variants with low level heteroplasmy.


Asunto(s)
ADN Mitocondrial/genética , Enfermedades Mitocondriales/genética , Adolescente , Adulto , Anciano , Femenino , Heteroplasmia , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Patrón de Herencia , Masculino , Persona de Mediana Edad , Conformación de Ácido Nucleico , Análisis de Secuencia de ADN
12.
J Fish Biol ; 97(1): 302-308, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32347542

RESUMEN

The present study established the southernmost distribution range for the Chupare stingray Styracura schmardae based on a specimen caught on the easternmost portion of Ceará State, northeastern Brazil. Identification was based on diagnostic morphological characters and molecular data (sequence of the mitochondrial DNA gene nd2; 1046 bp). This record expands the known distribution range for this species by more than 1200 km and confirms that S. schmardae is distributed in more than one biogeographical province. SIGNIFICANCE STATEMENT: There are few records of the Atlantic Chupare stingray for Brazil and most of them are associated with the Amazon River mouth. New records indicate that this species is also present in the South Atlantic portion of the Brazilian coast. Apparently having a low abundance throughout its range, these new records increase the range of occurrence of this species.


Asunto(s)
Distribución Animal/fisiología , Rajidae/fisiología , Animales , Brasil , ADN Mitocondrial , Ríos , Rajidae/genética
13.
J Environ Manage ; 233: 107-119, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30576958

RESUMEN

A simple and clean synthesis for Nd2Sn2O7-SnO2 nanocomposites as high-efficiency visible-light responsive photocatalyst is described applying extract of pineapple, for the first time. As novel and non-toxic biofuel, extract of pineapple, is employed to fabricate Nd2Sn2O7-SnO2 nanocomposites through an environment-friendly procedure. The findings denote that the applied biofuel can play a meaningful role as capping agent during preparation of Nd2Sn2O7-SnO2 nanocomposites. Depending on the applied dosage of pineapple extract as well as time for fabrication, the grain size, photocatalytic yield and morphology of Nd2Sn2O7-SnO2 structures changed. A suite of identification methods like XRD, TEM, EDS, DRS, BET and FESEM are utilized for investigation of the produced Nd2Sn2O7-SnO2 nanocomposites. Nd2Sn2O7-SnO2 structures are utilized as visible-light responsive photocatalyst to degrade the rhodamine B and eosin Y contaminants. The produced Nd2Sn2O7-SnO2 nanocomposites have been found to be very effective as visible-light responsive photocatalyst to degrade contaminants which may bring to environmental pollution.


Asunto(s)
Contaminantes Ambientales , Agua , Catálisis , Fotólisis , Compuestos de Estaño
14.
Mol Phylogenet Evol ; 113: 139-149, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-28545973

RESUMEN

The mountains of Borneo are well known for their high endemicity and historical role in preserving Southeast Asian rainforest biodiversity, but the diversification of populations inhabiting these mountains is poorly studied. Here we examine the genetic structure of 12 Bornean montane passerines by comparing complete mtDNA ND2 gene sequences of populations spanning the island. Maximum likelihood and Bayesian phylogenetic trees and haplotype networks are examined for common patterns that might signal important historical events or boundaries to dispersal. Morphological and ecological characteristics of each species are also examined using phylogenetic generalized least-squares (PGLS) for correlation with population structure. Populations in only four of the 12 species are subdivided into distinct clades or haplotype groups. Although this subdivision occurred at about the same time in each species (ca. 0.6-0.7Ma), the spatial positioning of the genetic break differs among the species. In two species, northeastern populations are genetically divergent from populations elsewhere on the island. In the other two species, populations in the main Bornean mountain chain, including the northeast, are distinct from those on two isolated peaks in northwestern Borneo. We suggest different historical forces played a role in shaping these two distributions, despite commonality in timing. PGLS analysis showed that only a single characteristic-hand-wing index-is correlated with population structure. Birds with longer wings, and hence potentially more dispersal power, have less population structure. To understand historical forces influencing montane population structure on Borneo, future studies must compare populations across the entirety of Sundaland.


Asunto(s)
Biodiversidad , Evolución Biológica , Ecología , Passeriformes/fisiología , Animales , Teorema de Bayes , Borneo , Haplotipos/genética , Análisis de los Mínimos Cuadrados , Filogenia , Filogeografía , Especificidad de la Especie
15.
BMC Genet ; 18(1): 53, 2017 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-28577537

RESUMEN

BACKGROUND: The South West Indian Ocean (SWIO) archipelagos and Madagascar constitute a hotspot of biodiversity with a high rate of endemism. In this area, the endemic subspecies A. m. unicolor has been described in Madagascar. It belongs to the African lineage, one of the four described evolutionary lineages in honey bees. Despite a long beekeeping tradition and several recorded European introductions, few studies have been carried out on the diversity and proportion of honey bee subspecies. In order to identify and define which evolutionary lineages and potential sub-lineages are present in the SWIO, the COI-COII intergenic region and the ND2 gene of the mtDNA were sequenced in honey bee colonies from three archipelagos. An extensive sampling (n = 1184 colonies) was done in the Mascarene (La Réunion, Mauritius, Rodrigues), Seychelles (Mahé, Praslin, La Digue) and Comoros (Grande Comore, Mohéli, Anjouan, Mayotte) archipelagos. Islands genetic diversity was compared to newly sampled populations from Madagascar, continental African and European populations. RESULTS: African lineage haplotypes were found in all islands (except for Rodrigues). Madagascar, Comoros and Seychelles had 100% of A lineage, 95.5% in La Réunion and 56.1% in Mauritius. Among all African colonies detected in the SWIO, 98.1% (n = 633) of COI-COII haplotypes described the presence of the subspecies A. M. unicolor. Both genetic markers revealed i) a new private AI mitochondrial group shared by the SWIO archipelagos and Madagascar distant from continental populations; ii) the private African haplotypes for each island suggested diversity radiation in the archipelagos; iii) the detection of the Comoros archipelago as a possible contact area between insular and continental African populations. The exotic European C and M lineages were only detected in the Mascarene archipelago, but striking differences of proportion were observed among islands. Merely 4.6% of European colonies were found in La Réunion whereas Mauritius cumulated 44%. Here, among the 84 observed COI-COII haplotypes, 50 were newly described including 13 which were private to the SWIO archipelagos and Madagascar. Similarly, 24 of the 34 found ND2 haplotypes were novel which included six haplotypes particular to the SWIO populations. CONCLUSION: A new African subgroup was described in the SWIO region with mitochondrial genetic evidence that A. m. unicolor is the indigenous subspecies of the archipelagos surrounding Madagascar.


Asunto(s)
Abejas/genética , ADN Mitocondrial , Variación Genética , África , Animales , Abejas/clasificación , Evolución Biológica , Haplotipos , Islas del Oceano Índico , Filogenia
16.
Mol Phylogenet Evol ; 95: 161-70, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26654959

RESUMEN

Several studies have recently reported evidence for positive selection acting on the mitochondrial genome (mitogenome), emphasizing its potential role in adaptive divergence and speciation. In this study we searched 107 full mitogenomes of recently diverged species and lineages of whitefish (Coregonus ssp.) for signals of positive selection. These salmonids show several distinct morphological and ecological differences that may be associated with energetics and therefore potentially positive selection at the mitogenome level. We found that purifying selection and genetic drift were the predominant evolutionary forces acting on the analyzed mitogenomes. However, the NADH dehydrogenase 2 gene (ND2) showed a highly elevated dN/dS ratio compared to the other mitochondrial genes, which was significantly higher in whitefish compared to other salmonids. We therefore further examined nonsynonymous evolution in ND2 by (i) mapping amino acid changes to a protein model structure which showed that they were located away from key functional residues of the protein, (ii) locating them in the sequences of other species of fish (Salmonidae, Anguillidae, Scombridae and Percidae) only to find pronounced overlap of nonsynonymous regions. We thus conclude that relaxed purifying selection is driving the evolution of ND2 by affecting mostly regions that have lower functional relevance.


Asunto(s)
Evolución Molecular , Genoma Mitocondrial , NADH Deshidrogenasa/genética , Salmonidae/genética , Selección Genética , Animales , Ecología , Genes Mitocondriales , Flujo Genético , Tasa de Mutación , Filogenia , Polimorfismo de Nucleótido Simple , Salmonidae/clasificación
17.
Int J Cancer ; 136(10): 2293-303, 2015 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-25348795

RESUMEN

Previous studies have evaluated the role of miRNAs in cancer initiation and progression. MiR-34a was found to be downregulated in several tumors, including medulloblastomas. Here we employed targeted transgenesis to analyze the function of miR-34a in vivo. We generated mice with a constitutive deletion of the miR-34a gene. These mice were devoid of mir-34a expression in all analyzed tissues, but were viable and fertile. A comprehensive standardized phenotypic analysis including more than 300 single parameters revealed no apparent phenotype. Analysis of miR-34a expression in human medulloblastomas and medulloblastoma cell lines revealed significantly lower levels than in normal human cerebellum. Re-expression of miR-34a in human medulloblastoma cells reduced cell viability and proliferation, induced apoptosis and downregulated the miR-34a target genes, MYCN and SIRT1. Activation of the Shh pathway by targeting SmoA1 transgene overexpression causes medulloblastoma in mice, which is dependent on the presence and upregulation of Mycn. Analysis of miR-34a in medulloblastomas derived from ND2:SmoA1(tg) mice revealed significant suppression of miR-34a compared to normal cerebellum. Tumor incidence was significantly increased and tumor formation was significantly accelerated in mice transgenic for SmoA1 and lacking miR-34a. Interestingly, Mycn and Sirt1 were strongly expressed in medulloblastomas derived from these mice. We here demonstrate that miR-34a is dispensable for normal development, but that its loss accelerates medulloblastomagenesis. Strategies aiming to re-express miR-34a in tumors could, therefore, represent an efficient therapeutic option.


Asunto(s)
Neoplasias Cerebelosas/patología , Cerebelo/metabolismo , Meduloblastoma/patología , MicroARNs/genética , MicroARNs/metabolismo , Animales , Línea Celular Tumoral , Proliferación Celular , Neoplasias Cerebelosas/genética , Neoplasias Cerebelosas/metabolismo , Regulación Neoplásica de la Expresión Génica , Técnicas de Inactivación de Genes , Humanos , Meduloblastoma/genética , Meduloblastoma/metabolismo , Ratones , Ratones Transgénicos , Fenotipo , Transducción de Señal
18.
Biodivers Data J ; 12: e134392, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39439904

RESUMEN

Background: Buforubroventromaculatus Orlov, Ananjeva, Ermakov, Lukonina, Ninh & Nguyen, 2024 is a species recently described from Vietnam. Currently, this species is known from central and northern Vietnam and it uncertain whether this species is distributed in China. In addition, the original description of this species is very brief. New information: Based on nine specimens collected from Yunnan Province and Guangxi Autonomous Region, China, we provide the first confirmed record of Buforubroventromaculatus from China. The morphological characteristics of the specimens from China mostly agree with the original description of B.rubroventromaculatus and, phylogenetically, the specimens from China clustered with the type series of B.rubroventromaculatus from Vietnam. We also provide a supplementary description of this species, based on the specimens we collected.

19.
Zookeys ; 1211: 101-130, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39262607

RESUMEN

A new karst-dwelling bent-toed gecko of the Cyrtodactylusintermedius group is described from Khlong Hat District, Sa Kaeo Province, eastern Thailand, based on an integrative taxonomic analysis of genetic data and morphological characteristics. Phylogenetic analyses using the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene revealed that topotypes of C.intermedius were sister to a clade containing C.kulenensis from Cambodia, an unnamed lineage from Sakaerat Biosphere Reserve in Nakhon Ratchasima Province, Thailand, and the Khlong Hat lineage described here as Cyrtodactyluskhlonghatensis sp. nov. Multivariate analyses of morphometric and meristic characters showed that C.khlonghatensis sp. nov. is morphologically distinct from all other species in the group by having the combination of SVL 76.5-82.8 mm in adult males and 88.5 mm in an adult female; eight supralabial and nine infralabial scales; 30-32 paravertebral tubercles; 20 or 21 longitudinal rows of dorsal tubercles; 43 or 44 ventral scales; seven or eight expanded subdigital lamellae on the 4th toe; 12 unmodified subdigital lamellae on the 4th toe; 19 or 20 total subdigital lamellae on the 4th toe; 31 or 32 total number of enlarged femoral scales; enlarged femoral and precloacal scales continuous; 6-8 pore-bearing precloacal scales in males; three or four rows of enlarged post-precloacal scales; 1-3 postcloacal tubercles; proximal femoral scales less than one-half the size of distal femoral scales; absence of interdigital pocketing between digits of forefeet and hindfeet; and posterior border of the nuchal loop rounded. Uncorrected pairwise genetic divergences (p-distances) between the new species and other species of the intermedius group ranged from 4.73-22.55%. The discovery of this new species exclusively in isolated karst formations from the Thai-Cambodia border suggests that there may be further undiscovered Cyrtodactylus in unexplored karst landscapes along the border of eastern Thailand and western Cambodia.

20.
Zookeys ; 1192: 83-102, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38419746

RESUMEN

We describe a new species of the genus Cyrtodactylus based on five adult specimens from Bac Ha District, Lao Cai Province, northern Vietnam. Cyrtodactyluslucisp. nov. is distinguished from the remaining Indochinese bent-toed geckos by a combination of the following morphological characteristics: medium size (SVL up to 89.5 mm); dorsal tubercles in 17-19 irregular transverse rows; ventral scales in 32-34 longitudinal rows at midbody; precloacal pores present in both sexes, 9 or 10 in males, 8 or 9 in females; 12-15 enlarged femoral scales on each thigh; femoral pores 9-12 in males, 5-10 in females; postcloacal tubercles 2-4; lamellae under toe IV 21-23; dorsal pattern consisting of 5 or 6 irregular dark bands, a thin neckband without V-shape or triangle shape in the middle, top of head with dark brown blotches; subcaudal scales transversely enlarged. Molecular phylogenetic analyses recovered the new species as the sister taxon to C.gulinqingensis from Yunnan Province, China, with strong support from all analyses and the two taxa are separated by approximately 8.87-9.22% genetic divergence based on a fragment of the mitochondrial ND2 gene. This is the first representative of Cyrtodactylus known from Lao Cai Province.

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