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1.
Mol Cell ; 81(15): 3160-3170.e9, 2021 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-34174184

RESUMEN

RelA-SpoT Homolog (RSH) enzymes control bacterial physiology through synthesis and degradation of the nucleotide alarmone (p)ppGpp. We recently discovered multiple families of small alarmone synthetase (SAS) RSH acting as toxins of toxin-antitoxin (TA) modules, with the FaRel subfamily of toxSAS abrogating bacterial growth by producing an analog of (p)ppGpp, (pp)pApp. Here we probe the mechanism of growth arrest used by four experimentally unexplored subfamilies of toxSAS: FaRel2, PhRel, PhRel2, and CapRel. Surprisingly, all these toxins specifically inhibit protein synthesis. To do so, they transfer a pyrophosphate moiety from ATP to the tRNA 3' CCA. The modification inhibits both tRNA aminoacylation and the sensing of cellular amino acid starvation by the ribosome-associated RSH RelA. Conversely, we show that some small alarmone hydrolase (SAH) RSH enzymes can reverse the pyrophosphorylation of tRNA to counter the growth inhibition by toxSAS. Collectively, we establish RSHs as RNA-modifying enzymes.


Asunto(s)
Toxinas Bacterianas/metabolismo , Guanosina Pentafosfato/metabolismo , Ligasas/metabolismo , ARN de Transferencia/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/farmacología , Bacilos Grampositivos Asporogénicos/química , Bacilos Grampositivos Asporogénicos/metabolismo , Guanosina Pentafosfato/química , Ligasas/química , Ligasas/genética , Fosforilación/efectos de los fármacos , Biosíntesis de Proteínas/efectos de los fármacos , Biosíntesis de Proteínas/fisiología , Inhibidores de la Síntesis de la Proteína/farmacología , Pirofosfatasas , Ribosomas/metabolismo
2.
EMBO J ; 42(24): e115076, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-37987153

RESUMEN

In most metazoans, centrioles are lost during oogenesis, ensuring that the zygote is endowed with the correct number of two centrioles, which are paternally contributed. How centriole architecture is dismantled during oogenesis is not understood. Here, we analyze with unprecedent detail the ultrastructural and molecular changes during oogenesis centriole elimination in Caenorhabditis elegans. Centriole elimination begins with loss of the so-called central tube and organelle widening, followed by microtubule disassembly. The resulting cluster of centriolar proteins then disappears gradually, usually moving in a microtubule- and dynein-dependent manner to the plasma membrane. Our analysis indicates that neither Polo-like kinases nor the PCM, which modulate oogenesis centriole elimination in Drosophila, do so in C. elegans. Furthermore, we demonstrate that the central tube protein SAS-1 normally departs initially from the organelle, which loses integrity earlier in sas-1 mutants. Overall, our work provides novel mechanistic insights regarding the fundamental process of oogenesis centriole elimination.


Asunto(s)
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animales , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Centriolos/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Microtúbulos/metabolismo , Drosophila/metabolismo , Oogénesis , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo
3.
EMBO J ; 41(20): e104582, 2022 10 17.
Artículo en Inglés | MEDLINE | ID: mdl-36093892

RESUMEN

The conserved nine-fold structural symmetry of the centriole is thought to be generated by cooperation between two mechanisms, one dependent on and the other independent of the cartwheel, a sub-centriolar structure consisting of a hub and nine spokes. However, the molecular entity of the cartwheel-independent mechanism has not been elucidated. Here, using Chlamydomonas reinhardtii mutants, we show that Bld10p/Cep135, a conserved centriolar protein that connects cartwheel spokes and triplet microtubules, plays a central role in this mechanism. Using immunoelectron microscopy, we localized hemagglutinin epitopes attached to distinct regions of Bld10p along two lines that connect adjacent triplets. Consistently, conventional and cryo-electron microscopy identified crosslinking structures at the same positions. In centrioles formed in the absence of the cartwheel, truncated Bld10p was found to significantly reduce the inter-triplet distance and frequently form eight-microtubule centrioles. These results suggest that the newly identified crosslinks are comprised of part of Bld10p/Cep135. We propose that Bld10p determines the inter-triplet distance in the centriole and thereby regulates the number of triplets in a cartwheel-independent manner.


Asunto(s)
Centriolos , Hemaglutininas , Centriolos/genética , Centriolos/metabolismo , Microscopía por Crioelectrón , Epítopos/metabolismo , Hemaglutininas/metabolismo , Microtúbulos/metabolismo
4.
Proc Natl Acad Sci U S A ; 120(15): e2300281120, 2023 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-37011202

RESUMEN

The performance optimization of isolated atomically dispersed metal active sites is critical but challenging. Here, TiO2@Fe species-N-C catalysts with Fe atomic clusters (ACs) and satellite Fe-N4 active sites were fabricated to initiate peroxymonosulfate (PMS) oxidation reaction. The AC-induced charge redistribution of single atoms (SAs) was verified, thus strengthening the interaction between SAs and PMS. In detail, the incorporation of ACs optimized the HSO5- oxidation and SO5·- desorption steps, accelerating the reaction progress. As a result, the Vis/TiFeAS/PMS system rapidly eliminated 90.81% of 45 mg/L tetracycline (TC) in 10 min. The reaction process characterization suggested that PMS as an electron donor would transfer electron to Fe species in TiFeAS, generating 1O2. Subsequently, the hVB+ can induce the generation of electron-deficient Fe species, promoting the reaction circulation. This work provides a strategy to construct catalysts with multiple atom assembly-enabled composite active sites for high-efficiency PMS-based advanced oxidation processes (AOPs).

5.
J Infect Dis ; 230(2): e486-e495, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-38438123

RESUMEN

BACKGROUND: The RTS,S/AS01E (RTS,S) malaria vaccine is recommended for children in malaria endemic areas. This phase 2b trial evaluates RTS,S fractional- and full-dose regimens in Ghana and Kenya. METHODS: In total, 1500 children aged 5-17 months were randomized (1:1:1:1:1) to receive RTS,S or rabies control vaccine. RTS,S groups received 2 full RTS,S doses at months 0 and 1 and either full (groups R012-20, R012-14-26) or fractional doses (one-fifth; groups Fx012-14-26, Fx017-20-32). RESULTS: At month 32 post-dose 1, vaccine efficacy against clinical malaria (all episodes) ranged from 38% (R012-20; 95% confidence interval [CI]: 24%-49%) to 53% (R012-14-26; 95% CI: 42%-62%). Vaccine impact (cumulative number of cases averted/1000 children vaccinated) was 1344 (R012-20), 2450 (R012-14-26), 2273 (Fx012-14-26), and 2112 (Fx017-20-32). To account for differences in vaccine volume (fractional vs full dose; post hoc analysis), we estimated cases averted/1000 RTS,S full-dose equivalents: 336 (R012-20), 490 (R012-14-26), 874 (Fx012-14-26), and 880 (Fx017-20-32). CONCLUSIONS: Vaccine efficacy was similar across RTS,S groups. Vaccine impact accounting for full-dose equivalence suggests that using fractional-dose regimens could be a viable dose-sparing strategy. If maintained through trial end, these observations underscore the means to reduce cost per regimen thus maximizing impact and optimizing supply. CLINICAL TRIALS REGISTRATION: NCT03276962 (ClinicalTrials.gov).


Asunto(s)
Vacunas contra la Malaria , Malaria Falciparum , Eficacia de las Vacunas , Humanos , Vacunas contra la Malaria/administración & dosificación , Vacunas contra la Malaria/inmunología , Ghana , Lactante , Kenia , Femenino , Masculino , Malaria Falciparum/prevención & control , Malaria Falciparum/epidemiología , Esquemas de Inmunización , Malaria/prevención & control , Plasmodium falciparum/inmunología
6.
Curr Issues Mol Biol ; 46(8): 8031-8052, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39194692

RESUMEN

Neuraminidases catalyze the desialylation of cell-surface glycoconjugates and play crucial roles in the development and function of tissues and organs. In both physiological and pathophysiological contexts, neuraminidases mediate diverse biological activities via the catalytic hydrolysis of terminal neuraminic, or sialic acid residues in glycolipid and glycoprotein substrates. The selective modulation of neuraminidase activity constitutes a promising strategy for treating a broad spectrum of human pathologies, including sialidosis and galactosialidosis, neurodegenerative disorders, cancer, cardiovascular diseases, diabetes, and pulmonary disorders. Structurally distinct as a large family of mammalian proteins, neuraminidases (NEU1 through NEU4) possess dissimilar yet overlapping profiles of tissue expression, cellular/subcellular localization, and substrate specificity. NEU1 is well characterized for its lysosomal catabolic functions, with ubiquitous and abundant expression across such tissues as the kidney, pancreas, skeletal muscle, liver, lungs, placenta, and brain. NEU1 also exhibits a broad substrate range on the cell surface, where it plays hitherto underappreciated roles in modulating the structure and function of cellular receptors, providing a basis for it to be a potential drug target in various human diseases. This review seeks to summarize the recent progress in the research on NEU1-associated diseases and highlight the mechanistic implications of NEU1 in disease pathogenesis. An improved understanding of NEU1-associated diseases should help accelerate translational initiatives to develop novel or better therapeutics.

7.
EMBO J ; 39(22): e106249, 2020 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-32954505

RESUMEN

Centrioles are polarized microtubule-based organelles that seed the formation of cilia, and which assemble from a cartwheel containing stacked ring oligomers of SAS-6 proteins. A cryo-tomography map of centrioles from the termite flagellate Trichonympha spp. was obtained previously, but higher resolution analysis is likely to reveal novel features. Using sub-tomogram averaging (STA) in T. spp. and Trichonympha agilis, we delineate the architecture of centriolar microtubules, pinhead, and A-C linker. Moreover, we report ~25 Å resolution maps of the central cartwheel, revealing notably polarized cartwheel inner densities (CID). Furthermore, STA of centrioles from the distant flagellate Teranympha mirabilis uncovers similar cartwheel architecture and a distinct filamentous CID. Fitting the CrSAS-6 crystal structure into the flagellate maps and analyzing cartwheels generated in vitro indicate that SAS-6 rings can directly stack onto one another in two alternating configurations: with a slight rotational offset and in register. Overall, improved STA maps in three flagellates enabled us to unravel novel architectural features, including of centriole polarity and cartwheel stacking, thus setting the stage for an accelerated elucidation of underlying assembly mechanisms.


Asunto(s)
Centriolos/ultraestructura , Microscopía por Crioelectrón/métodos , Tomografía/métodos , Adhesión Celular , Cilios/ultraestructura , Microtúbulos/ultraestructura , Parabasalidea/citología
8.
Small ; 20(1): e2304776, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37658502

RESUMEN

Efficient artificial photosynthesis of disulfide bonds holds promises to facilitate reverse decoding of genetic codes and deciphering the secrets of protein multilevel folding, as well as the development of life science and advanced functional materials. However, the incumbent synthesis strategies encounter separation challenges arising from leaving groups in the ─S─S─ coupling reaction. In this study, according to the reaction mechanism of free-radical-triggered ─S─S─ coupling, light-driven heterojunction functional photocatalysts are tailored and constructed, enabling them to efficiently generate free radicals and trigger the coupling reaction. Specifically, perovskites and covalent organic frameworks (COFs) are screened out as target materials due to their superior light-harvesting and photoelectronic properties, as well as flexible and tunable band structure. The in situ assembled Z-scheme heterojunction MAPB-M-COF (MAPbBr3 = MAPB, MA+ = CH3 NH2 + ) demonstrates a perfect trade-off between quantum efficiency and redox chemical potential via band engineering management. The MAPB-M-COF achieves a 100% ─S─S─ coupling yield with a record photoquantum efficiency of 11.50% and outstanding cycling stability, rivaling all the incumbent similar reaction systems. It highlights the effectiveness and superiority of application-oriented band engineering management in designing efficient multifunctional photocatalysts. This study demonstrates a concept-to-proof research methodology for the development of various integrated heterojunction semiconductors for light-driven chemical reaction and energy conversion.

9.
Appl Environ Microbiol ; 90(4): e0188523, 2024 04 17.
Artículo en Inglés | MEDLINE | ID: mdl-38451077

RESUMEN

Histone acetyltransferase (HAT)-mediated epigenetic modification is essential for diverse cellular processes in eukaryotes. However, the functions of HATs in the human pathogen Aspergillus fumigatus remain poorly understood. In this study, we characterized the functions of MOZ, Ybf2/Sas3, Sas2, and Tip60 (MYST)-family histone acetyltransferase something about silencing (Sas3) in A. fumigatus. Phenotypic analysis revealed that loss of Sas3 results in significant impairments in colony growth, conidiation, and virulence in the Galleria mellonella model. Subcellular localization and Western blot analysis demonstrated that Sas3 localizes to nuclei and is capable of acetylating lysine 9 and 14 of histone H3 in vivo. Importantly, we found that Sas3 is critical for the cell wall integrity (CWI) pathway in A. fumigatus as evidenced by hypersensitivity to cell wall-perturbing agents, altered cell wall thickness, and abnormal phosphorylation levels of CWI protein kinase MpkA. Furthermore, site-directed mutagenesis studies revealed that the conserved glycine residues G641 and G643 and glutamate residue E664 are crucial for the acetylation activity of Sas3. Unexpectedly, only triple mutations of Sas3 (G641A/G643A/E664A) displayed defective phenotypes similar to the Δsas3 mutant, while double or single mutations did not. This result implies that the role of Sas3 may extend beyond histone acetylation. Collectively, our findings demonstrate that MYST-family HAT Sas3 plays an important role in the fungal development, virulence, and cell wall integrity in A. fumigatus. IMPORTANCE: Epigenetic modification governed by HATs is indispensable for various cellular processes in eukaryotes. Nonetheless, the precise functions of HATs in the human pathogen Aspergillus fumigatus remain elusive. In this study, we unveil the roles of MYST-family HAT Sas3 in colony growth, conidiation, virulence, and cell wall stress response in A. fumigatus. Particularly, our findings demonstrate that Sas3 can function through mechanisms unrelated to histone acetylation, as evidenced by site-directed mutagenesis experiments. Overall, this study broadens our understanding of the regulatory mechanism of HATs in fungal pathogens.


Asunto(s)
Aspergillus fumigatus , Histona Acetiltransferasas , Humanos , Aspergillus fumigatus/genética , Aspergillus fumigatus/metabolismo , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/química , Histona Acetiltransferasas/metabolismo , Histonas/genética , Histonas/metabolismo , Virulencia , Pared Celular/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
10.
Stat Med ; 43(15): 2987-3004, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38727205

RESUMEN

Longitudinal data from clinical trials are commonly analyzed using mixed models for repeated measures (MMRM) when the time variable is categorical or linear mixed-effects models (ie, random effects model) when the time variable is continuous. In these models, statistical inference is typically based on the absolute difference in the adjusted mean change (for categorical time) or the rate of change (for continuous time). Previously, we proposed a novel approach: modeling the percentage reduction in disease progression associated with the treatment relative to the placebo decline using proportional models. This concept of proportionality provides an innovative and flexible method for simultaneously modeling different cohorts, multivariate endpoints, and jointly modeling continuous and survival endpoints. Through simulated data, we demonstrate the implementation of these models using SAS procedures in both frequentist and Bayesian approaches. Additionally, we introduce a novel method for implementing MMRM models (ie, analysis of response profile) using the nlmixed procedure.


Asunto(s)
Teorema de Bayes , Ensayos Clínicos como Asunto , Simulación por Computador , Modelos Estadísticos , Humanos , Estudios Longitudinales , Ensayos Clínicos como Asunto/métodos , Dinámicas no Lineales , Modelos de Riesgos Proporcionales , Interpretación Estadística de Datos
11.
J Nanobiotechnology ; 22(1): 45, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38291460

RESUMEN

Amorphous silica nanoparticles (ASNP) are among the nanomaterials that are produced in large quantities. ASNP have been present for a long time in several fast-moving consumer products, several of which imply exposure of the gastrointestinal tract, such as toothpastes, food additives, drug excipients, and carriers. Consolidated use and experimental evidence have consistently pointed to the very low acute toxicity and limited absorption of ASNP. However, slow absorption implies prolonged exposure of the intestinal epithelium to ASNP, with documented effects on intestinal permeability and immune gut homeostasis. These effects could explain the hepatic toxicity observed after oral administration of ASNP in animals. More recently, the role of microbiota in these and other ASNP effects has attracted increasing interest in parallel with the recognition of the role of microbiota in a variety of conditions. Although evidence for nanomaterial effects on microbiota is particularly abundant for materials endowed with bactericidal activities, a growing body of recent experimental data indicates that ASNPs also modify microbiota. The implications of these effects are recounted in this contribution, along with a discussion of the more important open issues and recommendations for future research.


Asunto(s)
Microbioma Gastrointestinal , Nanopartículas , Animales , Humanos , Dióxido de Silicio/toxicidad , Nanopartículas/toxicidad , Mucosa Intestinal
12.
J Emerg Med ; 67(1): e10-e21, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38806350

RESUMEN

BACKGROUND: As the mortality of severe acute pancreatitis (SAP) is significantly higher than those with mild or moderate severity, it is of clinical significance to identify patients most likely to develop SAP at the time of emergency department (ED) presentation. OBJECTIVES: The aim of this study was to compare the performance of the Bedside Index for Severity in Acute Pancreatitis (BISAP) and the Emergency Department SpO2, Age and SIRS (ED-SAS) scoring systems as early risk assessment tools for identifying patients at high-risk of developing SAP. METHODS: We retrospectively reviewed adult patients with AP presented to ED between January 2019-September 2022. We calculated the scores of each patient with the parameters of the initial data. The primary outcome was SAP. The secondary outcomes were 30-day mortality, intensive care admission, and identifying low-risk patients without complications. RESULTS: Of 415 patients, 34 (8.2%) developed SAP and 15 (3.6%) died. With regard to predicting SAP, BISAP and ED-SAS scores had similar discriminative ability with area under the curves (AUCs) of 0.84 (95% confidence interval [CI]:0.80-0.88) and 0.83 (95% CI:0.79-0.86), respectively (p = 0.642). At a cut-off score of ≥2 for SAP, sensitivity/specificity values were 73.5%/82.4% for BISAP, 76.5%/83.2% for ED-SAS. BISAP and ED-SAS scores of ≥3, yielded sensitivity/specificity values of 50%/95.8% and 35.3%/95.5%, respectively. BISAP and ED-SAS were also similar in predicting mortality (AUCs of 0.92 vs. 0.90, respectively) and intensive care unit admission (AUCs 0.91 vs. 0.91). CONCLUSION: The BISAP and ED-SAS scores performed similarly in predicting SAP, mortality, and intensive care unit admission. As an easily calculated tool early in the ED, ED-SAS may be helpful in disposition decisions for emergency physicians.


Asunto(s)
Servicio de Urgencia en Hospital , Pancreatitis , Índice de Severidad de la Enfermedad , Síndrome de Respuesta Inflamatoria Sistémica , Humanos , Masculino , Femenino , Servicio de Urgencia en Hospital/organización & administración , Persona de Mediana Edad , Estudios Retrospectivos , Pancreatitis/mortalidad , Pancreatitis/complicaciones , Pancreatitis/diagnóstico , Pancreatitis/fisiopatología , Síndrome de Respuesta Inflamatoria Sistémica/diagnóstico , Síndrome de Respuesta Inflamatoria Sistémica/mortalidad , Síndrome de Respuesta Inflamatoria Sistémica/fisiopatología , Anciano , Adulto , Medición de Riesgo/métodos , Valor Predictivo de las Pruebas , Saturación de Oxígeno/fisiología , Factores de Edad
13.
Int J Phytoremediation ; 26(2): 159-168, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37424147

RESUMEN

Sulfonamides (SAs) in agricultural soils can be degraded in rhizosphere, but can also be taken up by vegetables, which thereby poses human health and ecological risks. A glasshouse experiment was conducted using multi-interlayer rhizoboxes to investigate the fate of three SAs in rape and hot pepper rhizosphere soil systems to examine the relationship between the accumulation and their physicochemical processes. SAs mainly entered pepper shoots in which the accumulation ranged from 0.40 to 30.64 mg kg-1, while SAs were found at high levels in rape roots ranged from 3.01 to 16.62 mg kg-1. The BCFpepper shoot exhibited a strong positive linear relationship with log Dow, while such relationship was not observed between other bioconcentration factors (BCFs) and log Dow. Other than lipophilicity, the dissociation of SAs may also influence the uptake and translocation process. Larger TF and positive correlation with log Dow indicate preferential translocation of pepper SAs. There was a significant (p < 0.05) dissipation gradient of SAs observed away from the vegetable roots. In addition, pepper could uptake more SAs under solo exposure, while rape accumulated more SAs under combined exposure. When SAs applied in mixture, competition between SAs might occur to influence the translocation and dissipation patterns of SAs.


The phloem and xylem structure of plants and the neutral and ionic partitioning of sulfonamides (SAs) influence the uptake and translocation of SAs.A significant (p < 0.05) dissipation gradient of SAs was observed away from the vegetable roots.Combined exposure could promote the correlation between log BCF and log Dow.


Asunto(s)
Capsicum , Violación , Contaminantes del Suelo , Humanos , Sulfonamidas/metabolismo , Capsicum/metabolismo , Suelo , Rizosfera , Contaminantes del Suelo/metabolismo , Biodegradación Ambiental , Sulfanilamida/metabolismo , Raíces de Plantas/química , Verduras/metabolismo
14.
Pharm Stat ; 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38603591

RESUMEN

In pharmaceutical manufacturing, especially biologics and vaccines manufacturing, emphasis on speedy process development can lead to inadequate process development, which often results in less robust commercial manufacturing process after launch. Process performance index (Ppk) is a statistical measurement of the ability of a process to produce output within specification limits over a period of time. In biopharmaceutical manufacturing, progression in process development is based on Critical Quality Attributes meeting their specification limits, lacking insight into the process robustness. Ppk is typically estimated after 15-30 commercial batches at which point it may be too late/too complex to make process adjustments to enhance robustness. The use of Bayesian statistics, prior knowledge, and input from Subject matter experts (SMEs) offers an opportunity to make predictions on process capability during the development cycle. Developing a standard methodology to assess long term process capability at various stages of development provides several benefits: provides opportunity for early insight into process vulnerabilities thereby enabling resolution pre-licensure; identifies area of the process to prioritize and focus on during process development/process characterization (PC) using a data-driven approach; and ultimately results in higher process robustness/process knowledge at launch. We propose a Bayesian-based method to predict the performance of a manufacturing process at full manufacturing scale during the development and commercialization phase, before commercial data exists. Under Bayesian framework, limited development data for the process of interest at hand, data from similar products, general SME knowledge, and literature can be carefully formulated into informative priors. The implementation of the proposed approach is presented through two examples. To allow for continuous improvement during process development, we recommend to embed this approach of using predictive Ppk at pre-defined commercialization stage-gates, for example, at completion of process development, prior to and completion of PC, prior to technology transfer runs (Engineering/Process Performance Qualification, PPQ), and prior to commercial specification setting.

15.
Environ Geochem Health ; 46(7): 224, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38849581

RESUMEN

This study aimed to evaluate the effect of modified nanoscale zero-valent iron (SAS-nZVI) on chemical leaching of lead and cadmium composite contaminated soil by citric acid (CA). The synthesized SAS-nZVI was used as a leaching aid to improve the removal rate of soil heavy metals (HMs) by CA chemical leaching. The effects of various factors such as SAS-nZVI dosage, elution temperature and elution time were studied. At the same time, the effect of chemical leaching on the basic physical and chemical properties of soil and the morphology of HMs was evaluated. The results show that when the SAS-nZVI dosage is 2.0 g/L, the leaching temperature is 25 °C, and the leaching time is 720 min, the maximum removal rates of Pb and Cd in the soil are 77.64% and 97.15% respectively. The experimental results were evaluated using elution and desorption kinetic models (Elovich model, double constant model, diffusion model). The elution and desorption process of Pb and Cd in soil by SAS-nZVI-CA fitted well with the double-constant model, indicating that the desorption kinetic process of Pb and Cd is a heterogeneous diffusion process, and the elution process is controlled by diffusion factors. After leaching with SAS-nZVI-CA, the physical and chemical properties of the soil changed little, the mobility and toxicity of HMs in the soil were reduced, and the HMs content in the leaching waste liquid was reduced. It can be concluded that SAS-nZVI enhances the efficiency of CA in extracting Pb and Cd from soil, minimizes soil damage resulting from chemical leaching technology, and alleviates the challenges associated with treating leaching waste liquid.


Asunto(s)
Cadmio , Ácido Cítrico , Hierro , Plomo , Contaminantes del Suelo , Contaminantes del Suelo/química , Ácido Cítrico/química , Hierro/química , Cadmio/química , Plomo/química , Restauración y Remediación Ambiental/métodos , Nanopartículas del Metal/química , Metales Pesados/química , Cinética , Suelo/química , Temperatura
16.
J Biol Chem ; 298(12): 102658, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36356903

RESUMEN

Cartwheel assembly is considered the first step in the initiation of procentriole biogenesis; however, the reason for persistence of the assembled human cartwheel structure from S phase to late mitosis remains unclear. Here, we demonstrate mainly using cell synchronization, RNA interference, immunofluorescence and time-lapse-microscopy, biochemical analysis, and methods that the cartwheel persistently assembles and maintains centriole engagement and centrosome integrity during S phase to late G2 phase. Blockade of the continuous accumulation of centriolar Sas-6, a major cartwheel protein, after procentriole formation induces premature centriole disengagement and disrupts pericentriolar matrix integrity. Additionally, we determined that during mitosis, CDK1-cyclin B phosphorylates Sas-6 at T495 and S510, disrupting its binding to cartwheel component STIL and pericentriolar component Nedd1 and promoting cartwheel disassembly and centriole disengagement. Perturbation of this phosphorylation maintains the accumulation of centriolar Sas-6 and retains centriole engagement during mitotic exit, which results in the inhibition of centriole reduplication. Collectively, these data demonstrate that persistent cartwheel assembly after procentriole formation maintains centriole engagement and that this configuration is relieved through phosphorylation of Sas-6 by CDK1-cyclin B during mitosis in human cells.


Asunto(s)
Centriolos , Centrosoma , Humanos , Proteína Quinasa CDC2/metabolismo , Proteínas de Ciclo Celular/metabolismo , Centriolos/metabolismo , Centrosoma/metabolismo , Mitosis , Fosforilación , Proteínas/metabolismo , Ciclina B
17.
Plant Cell Physiol ; 64(5): 474-485, 2023 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-36715091

RESUMEN

Shade avoidance syndrome (SAS) is a strategy of major adaptive significance and typically includes elongation of the stem and petiole, leaf hyponasty, reduced branching and phototropic orientation of the plant shoot toward canopy gaps. Both cryptochrome 1 and phytochrome B (phyB) are the major photoreceptors that sense the reduction in the blue light fluence rate and the low red:far-red ratio, respectively, and both light signals are associated with plant density and the resource reallocation when SAS responses are triggered. The B-box (BBX)-containing zinc finger transcription factor BBX24 has been implicated in the SAS as a regulator of DELLA activity, but this interaction does not explain all the observed BBX24-dependent regulation in shade light. Here, through a combination of transcriptional meta-analysis and large-scale identification of BBX24-interacting transcription factors, we found that JAZ3, a jasmonic acid signaling component, is a direct target of BBX24. Furthermore, we demonstrated that joint loss of BBX24 and JAZ3 function causes insensitivity to DELLA accumulation, and the defective shade-induced elongation in this mutant is rescued by loss of DELLA or phyB function. Therefore, we propose that JAZ3 is part of the regulatory network that controls the plant growth in response to shade, through a mechanism in which BBX24 and JAZ3 jointly regulate DELLA activity. Our results provide new insights into the participation of BBX24 and JA signaling in the hypocotyl shade avoidance response in Arabidopsis.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Luz , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Fitocromo B/metabolismo , Regulación de la Expresión Génica de las Plantas
18.
Biochem Biophys Res Commun ; 683: 149108, 2023 11 26.
Artículo en Inglés | MEDLINE | ID: mdl-37862782

RESUMEN

The environmental and health risks associated with sulfonamide antibiotics (SAs) are receiving increasing attention. Through multi-spectroscopy, density functional theory (DFT), and molecular docking, this study investigated the interaction features and mechanisms between six representative SAs and human serum albumin (HSA). Multi-spectroscopy analysis showed that the six SAs had significant binding capabilities with HSA. The order of binding constants at 298 K was as follows: sulfadoxine (SDX): 7.18 × 105 L mol-1 > sulfamethizole (SMT): 6.28 × 105 L mol-1 > sulfamerazine (SMR): 2.70 × 104 L mol-1 > sulfamonomethoxine (SMM): 2.54 × 104 L mol-1 > sulfamethazine (SMZ): 3.06 × 104 L mol-1 > sulfadimethoxine (SDM): 2.50 × 104 L mol-1. During the molecular docking process of the six SAs with HSA, the binding affinity range is from -7.4 kcal mol-1 to -8.6 kcal mol-1. Notably, the docking result of HSA-SDX reached the maximum of -8.6 kcal mol-1, indicating that SDX may possess the highest binding capacity to HSA. HSA-SDX binding, identified as a static quenching and exothermic process, is primarily driven by hydrogen bonds (H bonds) or van der Waals (vdW) interactions. The quenching processes of SMR/SMZ/SMM/SDX/SMT to HSA are a combination of dynamic and static quenching, indicating an endothermic reaction. Hydrophobic interactions are primarily accountable for SMR/SMZ/SMM/SDX/SMT and HSA binding. Competition binding results revealed that the primary HSA-SAs binding sites are in the subdomain IB of the HAS structure, consistent with the results of molecule docking. The correlation analysis based on DFT calculations revealed an inherent relationship between the structural chemical features of SAs and the binding performance of HSA-SAs. The dual descriptor (DD) and the electrophilic Fukui function were found to have a significant relationship (0.71 and -0.71, respectively) with the binding constants of HSA-SAs, predicting the binding performance of SAs and HSA. These insights have substantial scientific value for evaluating the environmental risks of SAs as well as understanding their impact on biological life activities.


Asunto(s)
Albúmina Sérica Humana , Albúmina Sérica , Humanos , Albúmina Sérica Humana/metabolismo , Simulación del Acoplamiento Molecular , Albúmina Sérica/química , Teoría Funcional de la Densidad , Sulfonamidas , Unión Proteica , Espectrometría de Fluorescencia , Sitios de Unión , Antibacterianos , Sulfanilamida , Dicroismo Circular , Termodinámica
19.
EMBO Rep ; 22(2): e51127, 2021 02 03.
Artículo en Inglés | MEDLINE | ID: mdl-33410253

RESUMEN

Centrosomes, composed of two centrioles and pericentriolar material, organize mitotic spindles during cell division and template cilia during interphase. The first few divisions during mouse development occur without centrioles, which form around embryonic day (E) 3. However, disruption of centriole biogenesis in Sas-4 null mice leads to embryonic arrest around E9. Centriole loss in Sas-4-/- embryos causes prolonged mitosis and p53-dependent cell death. Studies in vitro discovered a similar USP28-, 53BP1-, and p53-dependent mitotic surveillance pathway that leads to cell cycle arrest. In this study, we show that an analogous pathway is conserved in vivo where 53BP1 and USP28 are upstream of p53 in Sas-4-/- embryos. The data indicate that the pathway is established around E7 of development, four days after the centrioles appear. Our data suggest that the newly formed centrioles gradually mature to participate in mitosis and cilia formation around the beginning of gastrulation, coinciding with the activation of mitotic surveillance pathway upon centriole loss.


Asunto(s)
Centriolos , Centrosoma , Animales , Interfase , Ratones , Mitosis/genética , Huso Acromático
20.
BMC Med Res Methodol ; 23(1): 293, 2023 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-38093221

RESUMEN

BACKGROUND: Using four case studies, we aim to provide practical guidance and recommendations for the analysis of cluster randomised controlled trials. METHODS: Four modelling approaches (Generalized Linear Mixed Models with parameters estimated by maximum likelihood/restricted maximum likelihood; Generalized Linear Models with parameters estimated by Generalized Estimating Equations (1st order or second order) and Quadratic Inference Function, for analysing correlated individual participant level outcomes in cluster randomised controlled trials were identified after we reviewed the literature. We systematically searched the online bibliography databases of MEDLINE, EMBASE, PsycINFO (via OVID), CINAHL (via EBSCO), and SCOPUS. We identified the above-mentioned four statistical analytical approaches and applied them to four case studies of cluster randomised controlled trials with the number of clusters ranging from 10 to 100, and individual participants ranging from 748 to 9,207. Results were obtained for both continuous and binary outcomes using R and SAS statistical packages. RESULTS: The intracluster correlation coefficient (ICC) estimates for the case studies were less than 0.05 and are consistent with the observed ICC values commonly reported in primary care and community-based cluster randomised controlled trials. In most cases, the four methods produced similar results. However, in a few analyses, quadratic inference function produced different results compared to the generalized linear mixed model, first-order generalized estimating equations, and second-order generalized estimating equations, especially in trials with small to moderate numbers of clusters. CONCLUSION: This paper demonstrates the analysis of cluster randomised controlled trials with four modelling approaches. The results obtained were similar in most cases, however, for trials with few clusters we do recommend that the quadratic inference function should be used with caution, and where possible a small sample correction should be used. The generalisability of our results is limited to studies with similar features to our case studies, for example, studies with a similar-sized ICC. It is important to conduct simulation studies to comprehensively evaluate the performance of the four modelling approaches.


Asunto(s)
Proyectos de Investigación , Humanos , Análisis por Conglomerados , Tamaño de la Muestra , Simulación por Computador , Modelos Lineales , Ensayos Clínicos Controlados Aleatorios como Asunto
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