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1.
Phys Chem Chem Phys ; 2024 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-39295593

RESUMEN

Employing low Tg polymers has fundamental limitations in providing the desirable ionic conductivity at ambient temperature due to the freezing of chain dynamics. The stiffening of polymer chains and the formation of highly ordered systems due to the crosslinks have influenced the ionic conductivity. Ionic conductivity of 1.02 × 10-5 S cm-1 was attained for the system that presented a quantum mechanical tunnelling mode of ion transport. A Na-ion transference number of 0.31 was achieved for 30 wt% of NaClO4 salt in a polycaprolactone (PCL) matrix with an electrochemical stability window of 3.6 V at 25 °C. High crystallinity and limited availability of free Na+ ions in the electrolyte have resulted in lower ionic conductivity. PCL-NaClO4 exhibited brilliant thermal stability and mechanical properties. The influence of cathode materials MnO2, V2O5 and I2 on the discharge characteristics of an electrochemical cell in the configuration cathode |(70 wt%)PCL-NaClO4(30 wt%)|Na has been studied.

2.
CBE Life Sci Educ ; 23(3): ar30, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38900940

RESUMEN

Use of high-stakes exams in a course has been associated with gender, racial, and socioeconomic inequities. We investigated whether offering students the opportunity to retake an exam makes high-stakes exams more equitable. Following the control value theory of achievement emotions, we hypothesized that exam retakes would increase students' perceived control over their performance and decrease the value of a single exam attempt, thereby maximizing exam performance. We collected data on exam scores and experiences with retakes from three large introductory biology courses and assessed the effect of optional exam retakes on gender, racial/ethnic, and socioeconomic disparities in exam scores. We found that Black/African American students and those who worked more than 20 h a week were less likely to retake exams. While exam retakes significantly improved student scores, they slightly increased racial/ethnic and socioeconomic disparities in scores partly because of these differences in participation rates. Most students reported that retake opportunities reduced their anxiety on the initial exam attempt. Together our results suggest that optional exam retakes could be a useful tool to improve student performance and reduce anxiety associated with high-stakes exams. However, barriers to participation must be examined and reduced for retakes to reduce disparities in scores.


Asunto(s)
Ansiedad , Evaluación Educacional , Identificación Social , Estudiantes , Humanos , Masculino , Femenino , Factores Socioeconómicos , Etnicidad
3.
Sci Transl Med ; 16(747): eadj7685, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38748774

RESUMEN

Intrahepatic cholangiocarcinoma (ICC) is an aggressive bile duct malignancy that frequently exhibits isocitrate dehydrogenase (IDH1/IDH2) mutations. Mutant IDH (IDHm) ICC is dependent on SRC kinase for growth and survival and is hypersensitive to inhibition by dasatinib, but the molecular mechanism underlying this sensitivity is unclear. We found that dasatinib reduced p70 S6 kinase (S6K) and ribosomal protein S6 (S6), leading to substantial reductions in cell size and de novo protein synthesis. Using an unbiased phosphoproteomic screen, we identified membrane-associated guanylate kinase, WW, and PDZ domain containing 1 (MAGI1) as an SRC substrate in IDHm ICC. Biochemical and functional assays further showed that SRC inhibits a latent tumor-suppressing function of the MAGI1-protein phosphatase 2A (PP2A) complex to activate S6K/S6 signaling in IDHm ICC. Inhibiting SRC led to activation and increased access of PP2A to dephosphorylate S6K, resulting in cell death. Evidence from patient tissue and cell line models revealed that both intrinsic and extrinsic resistance to dasatinib is due to increased phospho-S6 (pS6). To block pS6, we paired dasatinib with the S6K/AKT inhibitor M2698, which led to a marked reduction in pS6 in IDHm ICC cell lines and patient-derived organoids in vitro and substantial growth inhibition in ICC patient-derived xenografts in vivo. Together, these results elucidated the mechanism of action of dasatinib in IDHm ICC, revealed a signaling complex regulating S6K phosphorylation independent of mTOR, suggested markers for dasatinib sensitivity, and described a combination therapy for IDHm ICC that may be actionable in the clinic.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Colangiocarcinoma , Dasatinib , Isocitrato Deshidrogenasa , Mutación , Familia-src Quinasas , Animales , Humanos , Ratones , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Neoplasias de los Conductos Biliares/patología , Neoplasias de los Conductos Biliares/metabolismo , Neoplasias de los Conductos Biliares/genética , Neoplasias de los Conductos Biliares/tratamiento farmacológico , Moléculas de Adhesión Celular/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Colangiocarcinoma/tratamiento farmacológico , Colangiocarcinoma/patología , Colangiocarcinoma/metabolismo , Colangiocarcinoma/genética , Dasatinib/farmacología , Isocitrato Deshidrogenasa/metabolismo , Isocitrato Deshidrogenasa/genética , Mutación/genética , Fosforilación/efectos de los fármacos , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Transducción de Señal/efectos de los fármacos , Familia-src Quinasas/metabolismo , Familia-src Quinasas/antagonistas & inhibidores , Guanilato-Quinasas/genética , Guanilato-Quinasas/metabolismo , Proteína Fosfatasa 2/genética , Proteína Fosfatasa 2/metabolismo
4.
ACS Omega ; 8(46): 43632-43643, 2023 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-38033349

RESUMEN

Microstructure modification in sodium alginate (NaAlg)-based solid polymer electrolytes by the perchlorate (ClO4-) and acetate (CH3COO-) anions of sodium salts has been reported. ClO4- participates in the structure-breaking effect via inter/intramolecular hydrogen bond breaking, while CH3COO- changes the amorphous phase, as evident from X-ray diffraction studies. The larger size and negative charge delocalization of ClO4- have a plasticizing effect, resulting in a lower glass transition temperature (Tg) compared to CH3COO-. Decomposition temperature is strongly dependent on the type of anion. Scanning electron microscopy images showed divergent modifications in the surface morphology in both electrolyte systems, with variations in salt content. The mechanical properties of the NaAlg-NaClO4 electrolyte systems are better than those of the NaAlg-CH3 COONa system, indicating weak interactions in the latter. Although most of the studies focus on the cation influence on conductivity, the interaction of the anion and its size certainly have an influence on the properties of solid polymer electrolytes, which will be of interest in the near future for sodium ion-based electrolytes in energy storage devices.

5.
J Chem Educ ; 100(8): 2860-2872, 2023 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-37577453

RESUMEN

A parallel series of general chemistry courses for Life Science Majors was created in an effort to support students and improve general chemistry outcomes. We created a two-quarter enhanced general chemistry course series that is not remedial, but instead implements several evidence-based teaching practices including Process Oriented Guided Inquiry Learning (POGIL), Peer-Led Team Learning (PLTL), and the Learning Assistant (LA) model. We found that students who took enhanced general chemistry had higher persistence to the subsequent first organic chemistry course, and performed equally well in the organic course compared to their peers who took standard general chemistry. Students in the first enhanced general chemistry course also reported significantly higher belonging, although we were unable to determine if increased belonging was associated with the increased persistence to organic chemistry. Rather we found that the positive association between taking the enhanced general chemistry course and persistence to organic chemistry was mediated by higher grades received in the enhanced general chemistry course. Our findings highlight the responsibility we have as educators to carefully consider the pedagogical practices we use, in addition to how we assign student grades.

6.
Nat Cancer ; 4(3): 365-381, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36914816

RESUMEN

Adult liver malignancies, including intrahepatic cholangiocarcinoma and hepatocellular carcinoma, are the second leading cause of cancer-related deaths worldwide. Most individuals are treated with either combination chemotherapy or immunotherapy, respectively, without specific biomarkers for selection. Here using high-throughput screens, proteomics and in vitro resistance models, we identify the small molecule YC-1 as selectively active against a defined subset of cell lines derived from both liver cancer types. We demonstrate that selectivity is determined by expression of the liver-resident cytosolic sulfotransferase enzyme SULT1A1, which sulfonates YC-1. Sulfonation stimulates covalent binding of YC-1 to lysine residues in protein targets, enriching for RNA-binding factors. Computational analysis defined a wider group of structurally related SULT1A1-activated small molecules with distinct target profiles, which together constitute an untapped small-molecule class. These studies provide a foundation for preclinical development of these agents and point to the broader potential of exploiting SULT1A1 activity for selective targeting strategies.


Asunto(s)
Alquilantes , Neoplasias Hepáticas , Humanos , Sulfotransferasas , Neoplasias Hepáticas/tratamiento farmacológico , Arilsulfotransferasa
7.
J Immunother Cancer ; 11(3)2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36914208

RESUMEN

BACKGROUND: Cellular immunotherapies for cancer represent a means by which a patient's immune system can be augmented with high numbers of tumor-specific T cells. Chimeric antigen receptor (CAR) therapy involves genetic engineering to 'redirect' peripheral T cells to tumor targets, showing remarkable potency in blood cancers. However, due to several resistance mechanisms, CAR-T cell therapies remain ineffective in solid tumors. We and others have shown the tumor microenvironment harbors a distinct metabolic landscape that produces a barrier to immune cell function. Further, altered differentiation of T cells within tumors induces defects in mitochondrial biogenesis, resulting in severe cell-intrinsic metabolic deficiencies. While we and others have shown murine T cell receptor (TCR)-transgenic cells can be improved through enhanced mitochondrial biogenesis, we sought to determine whether human CAR-T cells could be enabled through a metabolic reprogramming approach. MATERIALS AND METHODS: Anti-EGFR CAR-T cells were infused in NSG mice which bore A549 tumors. The tumor infiltrating lymphocytes were analyzed for exhaustion and metabolic deficiencies. Lentiviruses carrying PPAR-gamma coactivator 1α (PGC-1α), PGC-1αS571A and NT-PGC-1α constructs were used to co-transduce T cells with anti-EGFR CAR lentiviruses. We performed metabolic analysis via flow cytometry and Seahorse analysis in vitro as well as RNA sequencing. Finally, we treated therapeutically A549-carrying NSG mice with either PGC-1α or NT-PGC-1α anti-EGFR CAR-T cells. We also analyzed the differences in the tumor-infiltrating CAR-T cells when PGC-1α is co-expressed. RESULTS: Here, in this study, we show that an inhibition resistant, engineered version of PGC-1α, can metabolically reprogram human CAR-T cells. Transcriptomic profiling of PGC-1α-transduced CAR-T cells showed this approach effectively induced mitochondrial biogenesis, but also upregulated programs associated with effector functions. Treatment of immunodeficient animals bearing human solid tumors with these cells resulted in substantially improved in vivo efficacy. In contrast, a truncated version of PGC-1α, NT-PGC-1α, did not improve the in vivo outcomes. CONCLUSIONS: Our data further support a role for metabolic reprogramming in immunomodulatory treatments and highlight the utility of genes like PGC-1α as attractive candidates to include in cargo along with chimeric receptors or TCRs for cell therapy of solid tumors.


Asunto(s)
Neoplasias , Receptores Quiméricos de Antígenos , Humanos , Animales , Ratones , Inmunoterapia Adoptiva/métodos , Receptores de Antígenos de Linfocitos T , Linfocitos T , Microambiente Tumoral
8.
Vaccine ; 41(5): 1081-1093, 2023 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-36604218

RESUMEN

Equid alphaherpesvirus 1 (EHV-1) infection causes significant health problems in equines. The EHV-1 infection leads to abortion storm in mares, respiratory disease and myeloencephalopathy. Despite the wide use of vaccines, the outbreaks of EHV-1 infections keep occurring globally, suggesting the need for the development of improved vaccines. Gene deletion attenuated mutant viruses could be a good candidate for the development of modified live vaccines. Here, we report the generation of mutant EHV-1 by deleting virulence (glycoprotein E & internal repeat 6; IR6) and immune evasive (pUL43 & pUL56) associated genes either individually or in combinations; and comprehensive evaluation of mutants through in vitro characterization followed by in vivo study in murine model to adjudge the attenuation of the virus and immune responses generated by mutants vis-à-vis wild type (wt) virus. The EHV-1 mutants with deletion of IR6 and gE genes (vToH-DMV) and four genes (i.e., gE, IR6, pUL43 and pUL56) (vToH-QMV) revealed a significant reduction in plaque size with minimal loss in replication efficiency in comparison to the wt virus. Further, in vivo studies showed virus attenuation adjudged through significant reduction in clinical signs, weight loss, gross and histopathological lesions in comparison to wt virus also revealed improved immune responses estimated through serum neutralization and flow cytometric analysis of CD4 + and CD8 + cell populations. Thus it can be concluded that EHV-1 mutants viz. vToH-DMV and vToH-QMV (novel combination) are promising vaccine candidates and qualify to be studied for adjudging the protective efficacy with wt virus challenge.


Asunto(s)
Infecciones por Herpesviridae , Herpesvirus Équido 1 , Enfermedades de los Caballos , Embarazo , Caballos , Animales , Femenino , Ratones , Herpesvirus Équido 1/genética , Inmunidad , Infecciones por Herpesviridae/veterinaria
9.
CBE Life Sci Educ ; 21(2): ar37, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35580002

RESUMEN

Sharing personal information can help instructors build relationships with students, and instructors revealing concealable stigmatized identities (CSIs) may be particularly impactful. One CSI is the LGBTQ+ identity, but there has been no research on the student-perceived impact of an instructor revealing this identity. In this exploratory study conducted at an institution in the U.S. Southwest, an instructor revealed that she identifies as LGBTQ+ to her undergraduate biology course in less than 3 seconds. We surveyed students (n = 475) after 8 weeks to assess whether they remembered this, and if so, how they perceived it affected them. We used regression models to assess whether students with different identities perceived a disproportionate impact of the reveal. Most students perceived the instructor revealing her LGBTQ+ identity positively impacted them; regression results showed LGBTQ+ students and women perceived greater increased sense of belonging and confidence to pursue a science career. Students overwhelmingly agreed that instructors revealing their LGBTQ+ identities to students is appropriate. This study is the first to indicate the perceived impact of an instructor revealing her LGBTQ+ identity to students in the United States and suggests that a brief intervention could positively affect students.


Asunto(s)
Minorías Sexuales y de Género , Estudiantes , Biología , Femenino , Humanos , Encuestas y Cuestionarios
10.
Pediatr Neurosurg ; 57(3): 175-183, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35203083

RESUMEN

INTRODUCTION: The literature indicates that decompression of Chiari I malformations (CM-1) may resolve symptoms of sleep apnea. This study aims to identify the incidence of obstructive sleep apnea (OSA), central sleep apnea (CSA), and mixed sleep apnea in a cohort of pediatric CM-1 patients treated at our institution. We also assessed apnea-hypopnea index and symptomatology before and after surgery to investigate if Chiari decompression is a viable treatment for sleep apnea in CM-1 patients. Improvement relative to ENT surgical intervention was also considered. METHODS: We identified 75 patients who underwent polysomnography (PSG) from our database of 465 CM-1 patients. Sleep apnea diagnosis was based on the sleep physician's overall interpretation of the PSG. Symptomatology pre- and post-surgery was analyzed. RESULTS: Of the 75 CM-1 patients that underwent PSG, 23 were diagnosed with sleep apnea. Sixteen had OSA, 6 had CSA, and 1 had mixed apnea. Twelve OSA patients received ENT intervention. Eight improved and 2 further improved after Chiari decompression. Of the 4 patients that did not improve, one of those later improved following Chiari decompression. Of the 6 CSA patients, 2 underwent Chiari decompression, but only one improved. The mixed apnea patient underwent several ENT interventions that did not relieve symptoms but improved following Chiari decompression. DISCUSSION/CONCLUSIONS: Based on our results, sleep apnea in CM-1 patients may be obstructive, central, or mixed and is likely multifactorial. A multidisciplinary approach to the management of these patients is important, including neurosurgery, otolaryngology, and sleep medicine. Future prospective studies will lend further insight into this condition and its management.


Asunto(s)
Malformación de Arnold-Chiari , Síndromes de la Apnea del Sueño , Apnea Central del Sueño , Apnea Obstructiva del Sueño , Malformación de Arnold-Chiari/complicaciones , Malformación de Arnold-Chiari/epidemiología , Malformación de Arnold-Chiari/cirugía , Niño , Humanos , Estudios Prospectivos , Estudios Retrospectivos , Síndromes de la Apnea del Sueño/diagnóstico , Síndromes de la Apnea del Sueño/epidemiología , Síndromes de la Apnea del Sueño/cirugía , Apnea Central del Sueño/diagnóstico , Apnea Central del Sueño/epidemiología , Apnea Central del Sueño/cirugía , Apnea Obstructiva del Sueño/complicaciones , Apnea Obstructiva del Sueño/epidemiología , Apnea Obstructiva del Sueño/cirugía
11.
CBE Life Sci Educ ; 21(1): ar10, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35044845

RESUMEN

Hundreds of articles have explored the extent to which individuals accept evolution, and the Measure of Acceptance of the Theory of Evolution (MATE) is the most often used survey. However, research indicates the MATE has limitations, and it has not been updated since its creation more than 20 years ago. In this study, we revised the MATE using information from cognitive interviews with 62 students that revealed response process errors with the original instrument. We found that students answered items on the MATE based on constructs other than their acceptance of evolution, which led to answer choices that did not fully align with their actual acceptance. Students answered items based on their understanding of evolution and the nature of science and different definitions of evolution. We revised items on the MATE, conducted 29 cognitive interviews on the revised version, and administered it to 2881 students in 22 classes. We provide response process validity evidence for the new measure through cognitive interviews with students, structural validity through a Rasch dimensionality analysis, and concurrent validity evidence through correlations with other measures of evolution acceptance. Researchers can now measure student evolution acceptance using this new version of the survey, which we have called the MATE 2.0.


Asunto(s)
Estudiantes , Humanos , Psicometría , Reproducibilidad de los Resultados , Encuestas y Cuestionarios
12.
CBE Life Sci Educ ; 20(3): ar42, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34283632

RESUMEN

Evolution is controversial among students and religiosity, religious affiliation, understanding of evolution, and demographics are predictors of evolution acceptance. However, quantitative research has not explored the unique impact of student perceived conflict between their religion and evolution as a major factor influencing evolution acceptance. We developed an instrument with validity evidence called "Perceived Conflict between Evolution and Religion" (PCoRE). Using this measure, we find that, among students in 26 biology courses in 11 states, adding student perceived conflict between their religion and evolution to linear mixed models more than doubled the capacity of the models to predict evolution acceptance compared with models that only included religiosity, religious affiliation, understanding of evolution, and demographics. Student perceived conflict between evolution and their religion was the strongest predictor of evolution acceptance among all variables and mediated the impact of religiosity on evolution acceptance. These results build upon prior literature that suggests that reducing perceived conflict between students' religious beliefs and evolution can help raise evolution acceptance levels. Further, these results indicate that including measures of perceived conflict between religion and evolution in evolution acceptance studies in the future is important.


Asunto(s)
Religión , Estudiantes , Humanos
13.
Nanoscale Adv ; 3(2): 508-516, 2021 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-36131732

RESUMEN

Constructing a heterostructure is an effective strategy to reduce the electron-hole recombination rate, which enhances photocatalytic activity. Here, we report a facile hydrothermal method to grow CdS nanoparticles on MnWO4 nanorods and their photocatalytic hydrogen generation under solar light. A structural study shows the decoration of hexagonal CdS nanoparticles on monoclinic MnWO4. Morphological studies based on FE-TEM analysis confirm the sensitization of CdS nanoparticles (10 nm) on MnWO4 nanorods of diameter-35 nm with mean length ∼100 nm. The lower PL intensity of MnWO4 was observed with an increasing amount of CdS nanoparticles, which shows inhibition of the charge carrier recombination rate. A CdS@MnWO4 narrow band gap semiconductor was employed for photocatalytic hydrogen generation from water under solar light and the highest amount of hydrogen, i.e. 3218 µmol h-1 g-1, is obtained which is 21 times higher than that with pristine MnWO4. The enhanced photocatalytic activity is ascribed to the formation of a CdS@MnWO4 nanoheterostructure resulting in efficient spatial separation of photogenerated electron-hole pairs due to vacancy defects. More significantly, direct Z-scheme electron transfer from MnWO4 to CdS is responsible for the enhanced hydrogen evolution. This work signifies that a CdS decorated MnWO4 nanoheterostructure has the potential to improve the solar to direct fuel conversion efficiency.

14.
PLoS One ; 15(12): e0243916, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33306720

RESUMEN

Online education has grown rapidly in recent years with many universities now offering fully online degree programs even in STEM disciplines. These programs have the potential to broaden access to STEM degrees for people with social identities currently underrepresented in STEM. Here, we ask to what extent is that potential realized in terms of student enrollment and grades for a fully online degree program. Our analysis of data from more than 10,000 course-enrollments compares student demographics and course grades in a fully online biology degree program to demographics and grades in an equivalent in-person biology degree program at the same university. We find that women, first-generation to college students and students eligible for federal Pell grants constitute a larger proportion of students in the online program compared to the in-person mode. However, the online mode of instruction is associated with lower course grades relative to the in-person mode. Moreover, African American/Black, Hispanic/Latinx, Native American, and Pacific Islander students as well as federal Pell grant eligible students earned lower grades than white students and non-Pell grant eligible students, respectively, but the grade disparities were similar among both in-person and online student groups. Finally, we find that grade disparities between men and women are larger online compared to in-person, but that for first-generation to college women, the online mode of instruction is associated with little to no grade gap compared to continuing generation women. Our findings indicate that although this online degree program broadens access for some student populations, inequities in the experience remain and need to be addressed in order for online education to achieve its inclusive mission.


Asunto(s)
Biología/educación , Educación a Distancia/tendencias , Universidades/tendencias , Logro , Adulto , Biología/tendencias , Curriculum , Escolaridad , Composición Familiar , Femenino , Humanos , Renta , Masculino , Pobreza , Estudiantes , Adulto Joven
15.
CBE Life Sci Educ ; 19(4): ar59, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33215970

RESUMEN

The evolution education experiences of students of color represent an emerging area of research, because past inquiries indicate these students have differential outcomes, such as lower evolution acceptance and severe underrepresentation in evolutionary biology. Religion is often an important support for students of color who are navigating a science, technology, engineering, and mathematics culture that privileges White nonreligious students. For instance, religion helps mitigate the negative effects of racism, but religious students are also more likely to experience conflict when learning evolution. In this nationwide study, we examined the extent to which strong religiosity among students of color can explain their lower evolution acceptance. We surveyed students in 77 college biology courses across 17 states and found that Black/African American students tend to be more religious and less accepting of evolution than any other racial/ethnic identity group and that Hispanic students tend to be slightly more religious and slightly less accepting of evolution than White students. Importantly, we find that religious background is an important factor associated with Black and Hispanic students' lower levels of evolution acceptance. This study suggests that the biology community should become more inclusive of Christian religious students if it wishes to foster inclusive evolution education for Black and Hispanic students.


Asunto(s)
Biología , Negro o Afroamericano , Hispánicos o Latinos , Religión , Estudiantes , Negro o Afroamericano/estadística & datos numéricos , Biología/educación , Biología/estadística & datos numéricos , Hispánicos o Latinos/estadística & datos numéricos , Humanos , Estudiantes/estadística & datos numéricos , Universidades
16.
Exp Cell Res ; 395(2): 112216, 2020 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-32768498

RESUMEN

SETDB1 is a histone methyltransferase that converts H3K9me2 to H3K9me3. SETDB1 activity and H3K9me3 are crucial for the formation of obligately silenced heterochromatin such as that of centromeres. Here we show that a microRNA, miR-152-3p, is involved in the regulation of SETDB1 protein levels, but surprisingly, miR-152-3p plays a positive regulatory role for SETDB1 expression. Inhibition of miR-152-3p by anti-miR treatment resulted in a robust reduction in SETDB1 protein levels, though SETDB1 mRNA levels were unaffected. This was also accompanied by a blockade of the biochemical pathway proceeding from H3K9me2 to H3K9me3 as evidenced by quantitative nucleosome ELISA assays that showed that H3K9me2 accumulates in cells treated with an anti-miR that targets miR-152-3p. In addition, the action of a miR-152-3p mimic increased flux of the reaction leading to H3K9me3. We also performed site-directed mutagenesis of three predicted miR-152-3p target recognition sequences to yield three precise deletions. Deletion of one of the three sites recapitulated the positive regulatory aspect of the action of miR-152-3p upon SETDB1 expression in a luciferase reporter assay. Previous studies have shown that miR-152-3p negatively regulates DNMT1, the sole maintenance DNA methyltransferase which is required for levels of 5-methylcytosine levels within DNA. Our results shown that miR-152-3p positively regulates the production of H3K9me3 by regulating the production of SETDB1. Therefore, our findings provide strong evidence that miR-152-3p can serve as a toggle switch that regulates the balance between DNA methylation and H3K9 histone methylation in constitutive heterochromatin.


Asunto(s)
Metilación de ADN/fisiología , N-Metiltransferasa de Histona-Lisina/metabolismo , Histonas/metabolismo , MicroARNs/genética , Heterocromatina/genética , Heterocromatina/metabolismo , N-Metiltransferasa de Histona-Lisina/genética , Humanos , Unión Proteica/genética , Unión Proteica/fisiología , Procesamiento Proteico-Postraduccional/genética
17.
Ecol Evol ; 10(10): 4280-4290, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32489596

RESUMEN

Competitive interactions between distantly related clades could cause complementary diversity patterns of these clades over large spatial scales. One such example might be ants and birds in the eastern Himalaya; ants are very common at low elevations but almost absent at mid-elevations where the abundance of other arthropods and insectivorous bird diversity peaks. Here, we ask if ants at low elevations could compete with birds for arthropod prey. Specifically, we studied the impact of the Asian weaver ant (Oecophylla smaragdina), a common aggressive ant at low elevations. Diet analysis using molecular methods demonstrate extensive diet overlap between weaver ants and songbirds at both low and mid-elevations. Trees without weaver ants have greater non-ant arthropod abundance and leaf damage. Experimental removal of weaver ants results in an increase in the abundance of non-ant arthropods. Notably, numbers of Coleoptera and Lepidoptera were most affected by removal experiments and were prominent components of both bird and weaver ant diets. Our results suggest that songbirds and weaver ants might potentially compete with each other for arthropod prey at low elevations, thereby contributing to lower insectivorous bird diversity at low elevations in eastern Himalaya. Competition with ants may shape vertebrate diversity patterns across broad biodiversity gradients.

18.
Am Nat ; 195(5): 802-817, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32364787

RESUMEN

Variation in species richness across environmental gradients results from a combination of historical nonequilibrium processes (time, speciation, extinction) and present-day differences in environmental carrying capacities (i.e., ecological limits affected by species interactions and the abundance and diversity of resources). In a study of bird richness along the subtropical east Himalayan elevational gradient, we test the prediction that species richness patterns are consistent with ecological limits using data on morphology, phylogeny, elevational distribution, and arthropod resources. Species richness peaks at midelevations. Occupied morphological volume is roughly constant from low elevations to midelevations, implying that more species are packed into the same space at midelevations compared with low elevations. However, variance in beak length and differences in beak length between close relatives decline with elevation, which is a consequence of the addition of many small insectivores at midelevations. These patterns are predicted from resource distributions: arthropod size diversity declines from low elevations to midelevations, largely because many more small insects are present at midelevations. Weak correlations of species mean morphological traits with elevation also match predictions based on resources and habitats. Elevational transects in the tropical Andes, New Guinea, and Tanzania similarly show declines in mean arthropod size and mean beak length and, in these cases, likely contribute to declining numbers of insectivorous bird species richness along these gradients. The results imply that conditions for ecological limits are met, although historical nonequilibrium processes are likely to also contribute to the pattern of species richness.


Asunto(s)
Altitud , Aves/fisiología , Ecosistema , Animales , Bután , Biodiversidad , Aves/clasificación , India
19.
Proc Biol Sci ; 286(1908): 20190745, 2019 08 14.
Artículo en Inglés | MEDLINE | ID: mdl-31362632

RESUMEN

Functional diversity is an important aspect of biodiversity, but its relationship to species diversity in time and space is poorly understood. Here we compare spatial patterns of functional and taxonomic diversity across marine and terrestrial systems to identify commonalities in their respective ecological and evolutionary drivers. We placed species-level ecological traits into comparable multi-dimensional frameworks for two model systems, marine bivalves and terrestrial birds, and used global species-occurrence data to examine the distribution of functional diversity with latitude and longitude. In both systems, tropical faunas show high total functional richness (FR) but low functional evenness (FE) (i.e. the tropics contain a highly skewed distribution of species among functional groups). Functional groups that persist toward the poles become more uniform in species richness, such that FR declines and FE rises with latitude in both systems. Temperate assemblages are more functionally even than tropical assemblages subsampled to temperate levels of species richness, suggesting that high species richness in the tropics reflects a high degree of ecological specialization within a few functional groups and/or factors that favour high recent speciation or reduced extinction rates in those groups.


Asunto(s)
Biodiversidad , Aves , Bivalvos , Ecosistema , Animales , Geografía , Modelos Biológicos
20.
Cancer Discov ; 9(8): 1064-1079, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31109923

RESUMEN

ATP-competitive fibroblast growth factor receptor (FGFR) kinase inhibitors, including BGJ398 and Debio 1347, show antitumor activity in patients with intrahepatic cholangiocarcinoma (ICC) harboring activating FGFR2 gene fusions. Unfortunately, acquired resistance develops and is often associated with the emergence of secondary FGFR2 kinase domain mutations. Here, we report that the irreversible pan-FGFR inhibitor TAS-120 demonstrated efficacy in 4 patients with FGFR2 fusion-positive ICC who developed resistance to BGJ398 or Debio 1347. Examination of serial biopsies, circulating tumor DNA (ctDNA), and patient-derived ICC cells revealed that TAS-120 was active against multiple FGFR2 mutations conferring resistance to BGJ398 or Debio 1347. Functional assessment and modeling the clonal outgrowth of individual resistance mutations from polyclonal cell pools mirrored the resistance profiles observed clinically for each inhibitor. Our findings suggest that strategic sequencing of FGFR inhibitors, guided by serial biopsy and ctDNA analysis, may prolong the duration of benefit from FGFR inhibition in patients with FGFR2 fusion-positive ICC. SIGNIFICANCE: ATP-competitive FGFR inhibitors (BGJ398, Debio 1347) show efficacy in FGFR2-altered ICC; however, acquired FGFR2 kinase domain mutations cause drug resistance and tumor progression. We demonstrate that the irreversible FGFR inhibitor TAS-120 provides clinical benefit in patients with resistance to BGJ398 or Debio 1347 and overcomes several FGFR2 mutations in ICC models.This article is highlighted in the In This Issue feature, p. 983.


Asunto(s)
Adenosina Trifosfato/metabolismo , Colangiocarcinoma/genética , Colangiocarcinoma/metabolismo , Resistencia a Antineoplásicos/genética , Inhibidores de Proteínas Quinasas/farmacología , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/antagonistas & inhibidores , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/genética , Adulto , Anciano , Línea Celular Tumoral , Colangiocarcinoma/diagnóstico , ADN Tumoral Circulante , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mutación , Proteínas de Fusión Oncogénica/antagonistas & inhibidores , Proteínas de Fusión Oncogénica/genética , Compuestos de Fenilurea/farmacología , Inhibidores de Proteínas Quinasas/química , Pirimidinas/farmacología , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/química , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad , Tomografía Computarizada por Rayos X
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