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1.
Org Biomol Chem ; 2024 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-39382477

RESUMEN

A triflate salt-catalyzed nonhydrolytic method for the deacylation of N-acylsulfonamides and subsequent one-pot condensation of the newly formed sulfonamides with N,N-dimethylformamide dimethyl acetal to provide N-sulfonylamidines is presented. A range of aliphatic and aromatic N-acylsulfonamides bearing various N-acyl groups such as acetyl, propionyl, butyrl, isobutyryl, octanoyl, benzoyl, 2-phenylacetyl, and sterically hindered pivaloyl are readily transformed into the corresponding N-sulfonylamidines in good to excellent yields. A variety of functional groups including halogeno, keto, nitro, cyano, hydroxyl, ether, and carboxylic ester are tolerated intact.

2.
Foods ; 13(18)2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39335863

RESUMEN

Pecan seed oil is a valuable source of essential fatty acids and various bioactive compounds; however, the functions of microRNAs and their targets in oil biosynthesis during seed development are still unknown. Here, we found that the oil content increased rapidly in the three early stages in three cultivars, and that oleic acid was the predominant fatty acid component in the mature pecan embryos. We identified, analyzed, and validated the expression levels of miRNAs related to seed development and oil biosynthesis, as well as their potential target genes, using small RNA sequencing data from three stages (120, 135, and 150 days after flowering). During the seed development process, 365 known and 321 novel miRNAs were discovered. In total, 91 known and 181 novel miRNAs were found to be differentially expressed, and 633 target genes were further investigated. The expression trend analysis revealed that the 91 known miRNAs were classified into eight groups, approximately two-thirds of which were up-regulated, whereas most novel miRNAs were down-regulated. The qRT-PCR and degradome sequencing data were used to identify five miRNA- target pairs. Overall, our study provides valuable insights into the molecular regulation of oil biosynthesis in pecan seeds.

4.
J Chem Inf Model ; 64(14): 5646-5656, 2024 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-38976879

RESUMEN

Predicting drug-target interactions (DTIs) is one of the crucial tasks in drug discovery, but traditional wet-lab experiments are costly and time-consuming. Recently, deep learning has emerged as a promising tool for accelerating DTI prediction due to its powerful performance. However, the models trained on limited known DTI data struggle to generalize effectively to novel drug-target pairs. In this work, we propose a strategy to train an ensemble of models by capturing both domain-generic and domain-specific features (E-DIS) to learn diverse domain features and adapt them to out-of-distribution data. Multiple experts were trained on different domains to capture and align domain-specific information from various distributions without accessing any data from unseen domains. E-DIS provides a comprehensive representation of proteins and ligands by capturing diverse features. Experimental results on four benchmark data sets in both in-domain and cross-domain settings demonstrated that E-DIS significantly improved model performance and domain generalization compared to existing methods. Our approach presents a significant advancement in DTI prediction by combining domain-generic and domain-specific features, enhancing the generalization ability of the DTI prediction model.


Asunto(s)
Aprendizaje Profundo , Descubrimiento de Drogas , Proteínas , Descubrimiento de Drogas/métodos , Proteínas/química , Proteínas/metabolismo , Ligandos , Preparaciones Farmacéuticas/química , Preparaciones Farmacéuticas/metabolismo , Dominios Proteicos
5.
Eur Radiol ; 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38940828

RESUMEN

OBJECTIVES: This study aimed to compare the safety and effectiveness of tunneled peripherally inserted central catheters (T-PICC) vs. conventional PICCs (C-PICC) in adult cancer patients. METHODS: A multicentre randomized controlled trial was conducted between April 2021 and January 2022 in seven hospitals in China. 564 participants were randomly assigned to T-PICC or C-PICC. These data were collected and compared: the baseline characteristics and catheterization-related characteristics, periprocedural complications, and long-term complications. RESULTS: Five-hundred fifty-three participants (aged, 52.6 ± 12.3 years; female, 39.1%) were ultimately analyzed. No significant differences in periprocedural complications were found between the T-PICC and C-PICC groups (all p > 0.05). Compared with C-PICC, T-PICC significantly reduced the incidence of long-term complications (26.4% vs. 39.9%, p < 0.001). Specifically, reduced complications were found in central line-associated bloodstream infection (1.8% vs. 5.1%, p = 0.04), thrombosis (1.1% vs. 4.0%, p = 0.03), catheter dislodgement (4.7% vs. 10.1%, p = 0.01), non-infectious oozing (17.3% vs. 28.6%, p = 0.002), local infection (3.6% vs. 7.6%, p = 0.04), skin irritation (6.1% vs. 10.9%, p = 0.046), and reduced unplanned catheter removal (2.2% vs. 7.2%, p = 0.005). No significant differences were found between T-PICC and C-PICC regarding catheter occlusion (6.5% vs. 5.8%, p = 0.73) or skin damage (2.2% vs. 2.9%, p = 0.58). CONCLUSION: T-PICC is safe and effectively reduces long-term complications. CLINICAL RELEVANCE STATEMENT: The tunneled technique is effective in reducing PICC-related long-term complications. Thus, it is recommended for cancer patients at high risk of PICC-related complications. TRIAL REGISTRATION: The registration number on https://www.chictr.org.cn/ is ChiCTR2100044632. The name of the trial registry is "A multicenter randomized controlled study of clinical use of tunneled vs. non-tunneled PICC". KEY POINTS: Cather-related complications are associated with the technique of catheterization. Compared with conventional PICC, tunneled PICC reduced catheter-related long-term complications. Tunneled PICC placement provides an alternative catheterization method for cancer patients.

6.
Dermatology ; 240(4): 606-614, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38735287

RESUMEN

INTRODUCTION: According to the common disease/rare variant hypothesis, it is important to study the role of rare variants in complex diseases. The association of rare variants with psoriasis has been demonstrated, but the association between rare variants and specific clinical subtypes of psoriasis has not been investigated. METHODS: Gene-based and gene-level meta-analyses were performed on data extracted from our previous study data sets (2,483 patients with guttate psoriasis and 8,292 patients with non-guttate psoriasis) for genotyping. Then, haplotype analysis was performed for rare loss-of-function variants located in MED12L, and protein function prediction was performed for MED12L. Gene-based analysis at each stage had a moderate significance threshold (p < 0.05). A χ2 test was then conducted on the three potential genes, and the merged gene-based analysis was used to confirm the results. We also conducted association analysis and meta-analysis for functional variants located on the identified gene. RESULTS: Through these gene-level analyses, we determined that MED12L is a guttate psoriasis susceptibility gene (p = 9.99 × 10-5), and the single-nucleotide polymorphism with the strongest association was rs199780529 (p_combine = 1 × 10-3, p_meta = 2 × 10-3). CONCLUSIONS: In our study, a guttate psoriasis-specific subtype-associated susceptibility gene was confirmed in a Chinese Han population. These findings contribute to a better genetic understanding of different subtypes of psoriasis.


Asunto(s)
Predisposición Genética a la Enfermedad , Complejo Mediador , Polimorfismo de Nucleótido Simple , Psoriasis , Humanos , China , Pueblos del Este de Asia/genética , Haplotipos , Complejo Mediador/genética , Psoriasis/genética
7.
Genet Test Mol Biomarkers ; 28(3): 123-130, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38546281

RESUMEN

Objective: This study aims to identify causal variants associated with vitiligo in an expanded region of 10q22.1. Materials and Methods: We conducted a fine-scale deep analysis of the expanded 10q22.1 region using in a large genome-wide association studies dataset consisting of 1117 cases and 1701 controls through imputation. We selected five nominal coding single nucleotide polymorphisms (SNPs) located in SLC29A3 and CDH23 and genotyped them in an independent cohort of 2479 cases and 2451 controls in a Chinese Han population cohort using the Sequenom MassArray iPLEX1 system. Results: A missense SNP in SLC29A3, rs2252996, showed strong evidence of association with vitiligo (p = 1.34 × 10-8, odds ratio [OR] = 0.82). Three synonymous SNPs (rs1084004 in SLC29A3; rs12218559 and rs10999978 in CDH23) provided suggestive evidence of association for vitiligo (p = 1.69 × 10-6, OR = 0.84; p = 9.47 × 10-5, OR = 1.18; p = 6.90 × 10-4, OR = 1.16, respectively). Stepwise conditional analyses identified two significant independent disease-associated signals from the four SNPs (both p < 0.05; both D' = 0.03; and r2 = 0.00). Conclusion: The study identifies four genetic coding variants in SLC29A3 and CDH23 on 10q22.1 that may contribute to vitiligo susceptibility with one missense variant affecting disease subphenotypes. The presence of multiple genetic variants underscores their significant role in the genetic pathogenesis of the disease.


Asunto(s)
Proteínas Relacionadas con las Cadherinas , Proteínas de Transporte de Nucleósidos , Vitíligo , Humanos , China , Estudio de Asociación del Genoma Completo , Genotipo , Proteínas de Transporte de Nucleósidos/genética , Vitíligo/genética , Pueblos del Este de Asia , Proteínas Relacionadas con las Cadherinas/genética
8.
Biotechnol Lett ; 46(2): 223-233, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38310624

RESUMEN

Bilirubin, a key active ingredient of bezoars with extensive clinical applications in China, is produced through a chemical process. However, this method suffers from inefficiency and adverse environmental impacts. To address this challenge, we present a novel and efficient approach for bilirubin production via whole-cell transformation. In this study, we employed Corynebacterium glutamicum ATCC13032 to express a ß-glucuronidase (StGUS), an enzyme from Staphylococcus sp. RLH1 that effectively hydrolyzes conjugated bilirubin to bilirubin. Following the optimization of the biotransformation conditions, a remarkable conversion rate of 79.7% in the generation of bilirubin was obtained at temperate 40 °C, pH 7.0, 1 mM Mg2+ and 6 mM antioxidant NaHSO3 after 12 h. These findings hold significant potential for establishing an industrially viable platform for large-scale bilirubin production.


Asunto(s)
Bilirrubina , Corynebacterium glutamicum , Glucuronidasa/genética , Glucuronidasa/metabolismo , Corynebacterium glutamicum/metabolismo , Staphylococcus , China
9.
Angew Chem Int Ed Engl ; 63(14): e202319480, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38317379

RESUMEN

Controlled synthesis of lead-halide perovskite crystals is challenging yet attractive because of the pivotal role played by the crystal structure and growth conditions in regulating their properties. This study introduces data-driven strategies for the controlled synthesis of oriented quasi-spherical CsPbBr3, alongside an investigation into the synthesis mechanism. High-throughput rapid characterization of absorption spectra and color under ultraviolet illumination was conducted using 23 possible ligands for the synthesis of CsPbBr3 crystals. The links between the absorption spectra slope (difference in the absorbance at 400 nm and 450 nm divided by a wavelength interval of 50 nm) and crystal size were determined through statistical analysis of more than 100 related publications. Big data analysis and machine learning were employed to investigate a total of 688 absorption spectra and 652 color values, revealing correlations between synthesis parameters and properties. Ex situ characterization confirmed successful synthesis of oriented quasi-spherical CsPbBr3 perovskites using polyvinylpyrrolidone and Acacia. Density functional theory calculations highlighted strong adsorption of Acacia on the (110) facet of CsPbBr3. Optical properties of the oriented quasi-spherical perovskites prepared with these data-driven strategies were significantly improved. This study demonstrates that data-driven controlled synthesis facilitates morphology-controlled perovskites with excellent optical properties.

10.
Healthcare (Basel) ; 12(3)2024 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-38338219

RESUMEN

BACKGROUND: Dementia has become one of the leading causes of death across the world. AIMS: The aim of this study was to investigate the incidence, prevalence, and mortality of dementia in China between 2010 and 2020, and to investigate any geographical, age, and sex differences in the prevalence and incidence of dementia. METHODS: Five databases were searched. The Joanna Briggs Institute (JBI) critical appraisal tool was used to assess the quality of the included studies. A random-effects meta-analysis was performed to estimate the pooled prevalence of dementia. Subgroup analysis was based on the type of dementia. The incidence and mortality of dementia were synthesized qualitatively. RESULTS: A total of 19 studies were included. The meta-analysis showed that the prevalence of dementia was 6% (95%CI 5%, 8%), the prevalence of Alzheimer's disease (AD) was 5% (95%CI 4%, 6%), and the prevalence of vascular dementia (VaD) was 1% (95%CI 0%, 2%). The subgroup analysis showed that the prevalence rates of dementia in rural (6%, 95%CI 4%, 8%) and urban areas were similar (6%, 95%CI 4%, 8%). Deaths due to dementia increased over time. CONCLUSION: The prevalence, incidence, and mortality of dementia increased with age and over time. Applying consistent criteria to the diagnosis of cognitive impairment and dementia is necessary to help with disease monitoring. Promoting dementia knowledge and awareness at the community level is necessary.

11.
Materials (Basel) ; 17(2)2024 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-38276430

RESUMEN

Research on perovskites has grown exponentially in the past decade due to the potential of methyl ammonium lead iodide in photovoltaics. Although these devices have achieved remarkable and competitive power conversion efficiency, concerns have been raised regarding the toxicity of lead and its impact on scaling up the technology. Eliminating lead while conserving the performance of photovoltaic devices is a great challenge. To achieve this goal, the research has been expanded to thousands of compounds with similar or loosely related crystal structures and compositions. Some materials are "re-discovered", and some are yet unexplored, but predictions suggest that their potential applications may go beyond photovoltaics, for example, spintronics, photodetection, photocatalysis, and many other areas. This short review aims to present the classification, some current mapping strategies, and advances of lead-free halide double perovskites, their derivatives, lead-free perovskitoid, and low-dimensional related crystals.

12.
Small ; 20(15): e2306360, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38010121

RESUMEN

Nanoplatelets (NPLs) share excellent luminescent properties with their symmetric quantum dots counterparts and entail special characters benefiting from the shape, like the thickness-dependent bandgap and anisotropic luminescence. However, perovskite NPLs, especially those based on iodide, suffer from poor spectral and phase stability. Here, stable CsPbI3 NPLs obtained by accelerating the crystallization process in ambient-condition synthesis are reported. By this kinetic control, the rectangular NPLs into quasi-square NPLs are tuned, where enlarged width endows the NPLs with a lower surface-area-to-volume ratio (S/V ratio), leading to lower surficial energy and thus improved endurance against NPL fusion (cause for spectral shift or phase transformation). The accelerated crystallization, denoting the fast nucleation and short period of growth in this report, is enabled by preparing a precursor with complete transformation of PbI2 into intermediates (PbI3 -), through an additional iodide supplier (e.g., zinc iodide). The excellent color stability of the materials remains in the light-emitting diodes under various bias stresses.

13.
Nat Commun ; 14(1): 8000, 2023 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-38044384

RESUMEN

Conventional spectroscopies are not sufficiently selective to comprehensively understand the behaviour of trapped carriers in perovskite solar cells, particularly under their working conditions. Here we use infrared optical activation spectroscopy (i.e., pump-push-photocurrent), to observe the properties and real-time dynamics of trapped carriers within operando perovskite solar cells. We compare behaviour differences of trapped holes in pristine and surface-passivated FA0.99Cs0.01PbI3 devices using a combination of quasi-steady-state and nanosecond time-resolved pump-push-photocurrent, as well as kinetic and drift-diffusion models. We find a two-step trap-filling process: the rapid filling (~10 ns) of low-density traps in the bulk of perovskite, followed by the slower filling (~100 ns) of high-density traps at the perovskite/hole transport material interface. Surface passivation by n-octylammonium iodide dramatically reduces the number of trap states (~50 times), improving the device performance substantially. Moreover, the activation energy (~280 meV) of the dominant hole traps remains similar with and without surface passivation.

14.
J Chem Theory Comput ; 19(22): 8460-8471, 2023 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-37947474

RESUMEN

Data-driven predictive methods that can efficiently and accurately transform protein sequences into biologically active structures are highly valuable for scientific research and medical development. Determining an accurate folding landscape using coevolutionary information is fundamental to the success of modern protein structure prediction methods. As the state of the art, AlphaFold2 has dramatically raised the accuracy without performing explicit coevolutionary analysis. Nevertheless, its performance still shows strong dependence on available sequence homologues. Based on the interrogation on the cause of such dependence, we presented EvoGen, a meta generative model, to remedy the underperformance of AlphaFold2 for poor MSA targets. By prompting the model with calibrated or virtually generated homologue sequences, EvoGen helps AlphaFold2 fold accurately in the low-data regime and even achieve encouraging performance with single-sequence predictions. Being able to make accurate predictions with few-shot MSA not only generalizes AlphaFold2 better for orphan sequences but also democratizes its use for high-throughput applications. Besides, EvoGen combined with AlphaFold2 yields a probabilistic structure generation method that could explore alternative conformations of protein sequences, and the task-aware differentiable algorithm for sequence generation will benefit other related tasks including protein design.


Asunto(s)
Algoritmos , Secuencia de Aminoácidos , Conformación Proteica
15.
Biochem Biophys Res Commun ; 684: 149131, 2023 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-37866242

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. A. muciniphila and its outer membrane protein Amuc_1100 ameliorate metabolic disorders, enteritis, depression, and other diseases in mice. The NAFLD mouse model was established by feeding a high-fat diet (HFD) for 10 weeks. To assess the effect of A. muciniphila and Amuc_1100 on NAFLD, we used atorvastatin, a common lipid-lowering drug, as a positive control. A. muciniphila and Amuc_1100 significantly reduced body weight and serum ALT and AST levels, and improved serum lipid levels in NAFLD mice, which had similar effects to Ator. In addition, A. muciniphila and Amuc_1100 decreased the concentration of LPS in the serum and upregulated the mRNA expression of the colonic tight junction proteins. In the liver, A. muciniphila and Amuc_1100 significantly reduced the mRNA expression levels of nodular receptor protein 3 (NLRP3) and Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB), and the protein and mRNA expression levels inflammatory cytokines. At the genus level, Amuc_1100 treatment significantly reduced the abundance of Coriobacteriaceae_UCG-002 produced by the HFD. The abundances of Blautia, norank_f__Ruminococcaceae, Lachnoclostridium, GCA-900066575 and Lachnospiraceae_UCG-006 increased dramatically. Together, A. muciniphila and Amuc_1100 alleviate HFD-induced NAFLD by acting on the gut-liver axis and regulating gut microbes.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Ratones , Animales , Enfermedad del Hígado Graso no Alcohólico/etiología , Enfermedad del Hígado Graso no Alcohólico/prevención & control , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Dieta Alta en Grasa/efectos adversos , Proteínas de la Membrana/metabolismo , Verrucomicrobia , Hígado/metabolismo , Lípidos , ARN Mensajero/metabolismo , Ratones Endogámicos C57BL
16.
Cancer Nurs ; 2023 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-37751308

RESUMEN

BACKGROUND: Global Cancer Statistics 2020 reported that breast cancer had exceeded lung cancer as the most frequently diagnosed cancer. Surgery is the primary treatment modality for breast cancer, but postoperative upper limb dysfunction often occurs; functional exercise can alleviate this and restore upper limb function. However, exercise compliance is low in postoperative breast cancer patients; thus, many studies have been conducted in recent years to improve patient compliance with exercise. OBJECTIVE: The aim of this study was to compare the effectiveness of different interventions to improve exercise adherence in postoperative breast cancer patients. METHODS: We searched PubMed, Cochrane Library, Web of Science, EMBASE, Wan Fang, CNKI, VIP, and CBM databases for eligible studies. Exercise adherence rate and quality-of-life difference were assessed as outcomes. Sensitivity analysis and inconsistency detection were performed to evaluate whether the exclusion of high-risk studies affected the validity. Risk of bias was assessed using the risk-of-bias table in RevMan 5.4. Surface under the cumulative ranking was used to estimate the rankings among different interventions. RESULTS: Twenty-five randomized controlled trials involving 9 interventions were included, and the network meta-analysis results showed that patients in the pedometer + counseling group had the best exercise adherence. CONCLUSION: Pedometer + counseling care measures are recommended to improve exercise adherence in postoperative breast cancer patients. IMPLICATIONS FOR PRACTICE: Oncology nurses can improve patients' exercise compliance through counseling and by giving them pedometers to wear.

17.
Water Res ; 243: 120343, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37482007

RESUMEN

Acid mine drainage (AMD) serves as an ideal model system for investigating microbial ecology, interaction, and assembly mechanism in natural environments. While previous studies have explored the structure and function of microbial communities in AMD, the succession patterns of microbial association networks and underlying assembly mechanisms during natural attenuation processes remain elusive. Here, we investigated prokaryotic microbial diversity and community assembly along an AMD-impacted river, from the extremely acidic, heavily polluted headwaters to the nearly neutral downstream sites. Microbial diversity was increased along the river, and microbial community composition shifted from acidophile-dominated to freshwater taxa-dominated communities. The complexity and relative modularity of the microbial networks were also increased, indicating greater network stability during succession. Deterministic processes, including abiotic selection of pH and high contents of sulfur and iron, governed community assembly in the headwaters. Although the stochasticity ratio was increased downstream, manganese content, microbial negative cohesion, and relative modularity played important roles in shaping microbial community structure. Overall, this study provides valuable insights into the ecological processes that govern microbial community succession in AMD-impacted riverine ecosystems. These findings have important implications for in-situ remediation of AMD contamination.


Asunto(s)
Ecosistema , Microbiota , Minería , Consorcios Microbianos , Agua Dulce , Hierro
18.
Int J Mol Sci ; 24(14)2023 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-37511313

RESUMEN

As crucial enzymes in the lipid metabolic network, long-chain acyl-CoA synthases (LACSs) are members of the acyl-activated enzyme superfamily and play a crucial role in epidermal wax synthesis, plant lipid anabolic metabolism, and stress tolerance. In this study, 11 pecan LACS genes were identified and categorized into five groups and located on nine chromosomes. The significant degree of conservation in the AtLACS and CiLACS protein sequences was demonstrated by multiple sequence alignment and conserved motif analysis. Cis-acting element analysis identified numerous stress-responsive and hormone-inducible elements in the promoter regions of CiLACS genes. The expression levels of CiLACS9 and CiLACS9-1 were considerably up-regulated under salt and drought stress, according to the qRT-RCR study. Treatment with ABA also led to increased expression levels of CiLACS1, CiLACS1-1, CiLACS2, and CiLACS9-1. Notably, CiLACS4, CiLACS4-1, CiLACS9, and CiLACS9-1 exhibited peak expression levels at 135 days after anthesis and are likely to have been crucial in the accumulation of seed kernel oil. Moreover, the CiLACS9 gene was shown to be located in the cytoplasm. These findings offer a theoretical framework for clarifying the roles of LACS genes in the processes of pecan kernel oil synthesis and response to abiotic stressors.


Asunto(s)
Carya , Carya/genética , Secuencia de Aminoácidos , Lípidos , Ligasas/metabolismo , Filogenia , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Fisiológico/genética
19.
Microbiome ; 11(1): 142, 2023 06 26.
Artículo en Inglés | MEDLINE | ID: mdl-37365664

RESUMEN

BACKGROUND: Phosphonates are the main components in the global phosphorus redox cycle. Little is known about phosphonate metabolism in freshwater ecosystems, although rapid consumption of phosphonates has been observed frequently. Cyanobacteria are often the dominant primary producers in freshwaters; yet, only a few strains of cyanobacteria encode phosphonate-degrading (C-P lyase) gene clusters. The phycosphere is defined as the microenvironment in which extensive phytoplankton and heterotrophic bacteria interactions occur. It has been demonstrated that phytoplankton may recruit phycospheric bacteria based on their own needs. Therefore, the establishment of a phycospheric community rich in phosphonate-degrading-bacteria likely facilitates cyanobacterial proliferation, especially in waters with scarce phosphorus. We characterized the distribution of heterotrophic phosphonate-degrading bacteria in field Microcystis bloom samples and in laboratory cyanobacteria "phycospheres" by qPCR and metagenomic analyses. The role of phosphonate-degrading phycospheric bacteria in cyanobacterial proliferation was determined through coculturing of heterotrophic bacteria with an axenic Microcystis aeruginosa strain and by metatranscriptomic analysis using field Microcystis aggregate samples. RESULTS: Abundant bacteria that carry C-P lyase clusters were identified in plankton samples from freshwater Lakes Dianchi and Taihu during Microcystis bloom periods. Metagenomic analysis of 162 non-axenic laboratory strains of cyanobacteria (consortia cultures containing heterotrophic bacteria) showed that 20% (128/647) of high-quality bins from eighty of these consortia encode intact C-P lyase clusters, with an abundance ranging up to nearly 13%. Phycospheric bacterial phosphonate catabolism genes were expressed continually across bloom seasons, as demonstrated through metatranscriptomic analysis using sixteen field Microcystis aggregate samples. Coculturing experiments revealed that although Microcystis cultures did not catabolize methylphosphonate when axenic, they demonstrated sustained growth when cocultured with phosphonate-utilizing phycospheric bacteria in medium containing methylphosphonate as the sole source of phosphorus. CONCLUSIONS: The recruitment of heterotrophic phosphonate-degrading phycospheric bacteria by cyanobacteria is a hedge against phosphorus scarcity by facilitating phosphonate availability. Cyanobacterial consortia are likely primary contributors to aquatic phosphonate mineralization, thereby facilitating sustained cyanobacterial growth, and even bloom maintenance, in phosphate-deficient waters. Video Abstract.


Asunto(s)
Cianobacterias , Microcystis , Organofosfonatos , Microcystis/genética , Microcystis/metabolismo , Ecosistema , Organofosfonatos/metabolismo , Cianobacterias/genética , Fitoplancton , Lagos/microbiología , Fósforo/metabolismo
20.
Front Plant Sci ; 14: 1186818, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37313261

RESUMEN

Nitrogen (N) limits plant productivity, and its uptake and assimilation may be regulated by N sources, N assimilating enzymes, and N assimilation genes. Mastering the regulatory mechanisms of N uptake and assimilation is a key way to improve plant nitrogen use efficiency (NUE). However, it is poorly known how these factors interact to influence the growth process of pecans. In this study, the growth, nutrient uptake and N assimilation characteristics of pecan were analyzed by aeroponic cultivation at varying NH4 +/NO3 - ratios (0/0, 0/100,25/75, 50/50, 75/25,100/0 as CK, T1, T2, T3, T4, and T5). The results showed that T4 and T5 treatments optimally promoted the growth, nutrient uptake and N assimilating enzyme activities of pecan, which significantly increased aboveground biomass, average relative growth rate (RGR), root area, root activity, free amino acid (FAA) and total organic carbon (TOC) concentrations, nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (Fd-GOGAT and NADH-GOGAT), and glutamate dehydrogenase (GDH) activities. According to the qRT-PCR results, most of the N assimilation genes were expressed at higher levels in leaves and were mainly significantly up-regulated under T1 and T4 treatments. Correlation analysis showed that a correlation between N assimilating enzymes and N assimilating genes did not necessarily exist. The results of partial least squares path model (PLS-PM) analysis indicated that N assimilation genes could affect the growth of pecan by regulating N assimilation enzymes and nutrients. In summary, we suggested that the NH4 +/NO3 - ratio of 75:25 was more beneficial to improve the growth and NUE of pecan. Meanwhile, we believe that the determination of plant N assimilation capacity should be the result of a comprehensive analysis of N concentration, N assimilation enzymes and related genes.

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