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1.
Environ Res ; : 119530, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-39004391

RESUMO

With stringent regulations of internal combustion engine on reducing CO2 emission, ammonia has been used as an alternative fuel. Investigating how engine-related performance is affected by partial ammonia replacement of diesel fuel is essential for understanding the combustion. Therefore, in this study, a three-dimensional numerical simulation model is developed for the burning of two fuels of diesel and ammonia based on relevant parameters (i.e., compression ratio, load, ammonia energy fraction, etc.) in a lab-made diesel engine. The consequences of load and compression proportion on combustion and pollutant emissions are investigated for ammonia energy fractions between 50% and 90%. When the ammonia portion rises, the increased ammonia equivalent ratio causes ammonia to move away from the dilute combustion boundary and accelerates the combustion rate of ammonia. An increase in compression ratio significantly increases the specified thermal performance and combustion efficacy. When the compression ratio is 16, as the ammonia energy fractions increases, due to the increase in the proportion of ammonia, that is, the proportion of nitrogen atoms increases, more NOx is generated during the combustion process. When the ammonia substitution rate is 90%, as the compression ratio increases, the cylinder pressure and temperature increase. The combustion efficiency of ammonia increases, generating more NOx and NOx emissions can reach 0.66 mg/m3. At a compression ratio of 18, the NOx emissions can reach 1.59 mg/m3. However, under medium and low load conditions, as the ammonia fraction increases, the total energy of fuel decreases, and the combustion efficiency of ammonia decreases, resulting in a decrease in the heat released during combustion and a decrease in NOx emissions. When the ammonia substitution rate is 90% and the load is 25%, NOx emissions reach 0.1 mg/m3. This research provides theoretical suggestions for the profitable and use ammonia fuel in internal combustion engines in a clean manner.

2.
Int J Biol Macromol ; : 133873, 2024 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-39013505

RESUMO

In this study, based on the self-assembly strategy, we fused CipA with carbonyl reductase LXCARS154Y derived from Leifsonia xyli by gene coding, and successfully performed the carrier-free immobilization of LXCARS154Y. The immobilized enzyme was then characterized using scanning electron microscope (SEM), dynamic light scattering (DLS) and fourier transform infrared spectroscopy (FTIR). Compared with the free enzyme, the immobilized LXCARS154Y exhibited a 2.3-fold improvement in the catalytic efficiency kcat/km for the synthesis of a chiral pharmaceutical intermediate (R)-3,5-bis(trifluoromethyl)phenyl ethanol ((R)-BTPE) by reducing 3,5-bis(trifluoromethyl)acetophenone (BTAP). Moreover, the immobilized enzyme showed the enhanced stability while maintaining over 61 % relative activity after 18 cycles of batch reaction. Further, when CipA-fused carbonyl reductase was employed for (R)-BTPE production in a continuous flow reaction, almost complete yield (97.0 %) was achieved within 7 h at 2 M (512.3 g/L) of BTAP concentration, with a space-time yield of 1717.1 g·L-1·d-1. Notably, we observed the retention of cofactor NADH by CipA-based enzyme aggregates, resulting in a higher total turnover number (TTN) of 4815 to facilitate this bioreductive process. This research developed a concise strategy for efficient preparation of chiral intermediate with cofactor self-sufficiency via continuous flow biocatalysis, and the relevant mechanism was also explored.

3.
Bioresour Bioprocess ; 11(1): 66, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38980516

RESUMO

Earthworm cultivation can effectively promote the resource utilization of agricultural waste. The efficient utilization of agricultural waste by earthworms mainly depends on the microbial communities in the guts. This study used silkworm excrement and cow manure as substrates for earthworm cultivation and investigated the associated bacterial communities during earthworms' growth. The survival rate of earthworms remained above 89% after 21 days of feeding with the two substrates. Proteobacteria, Actinobacteria, and Firmicutes constituted the predominant bacterial communities in earthworm growth, accounting for over 81% of the relative abundance in both guts and vermicompost. The bacteria richness and diversity in the foregut and midgut of earthworm were lower than those in the hindgut. The prediction function of intestinal bacterial communities of earthworms cultured with two substrates mainly involved biosynthesis, decomposition and energy production.

4.
J Clin Immunol ; 44(7): 155, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38922539

RESUMO

PURPOSE: Moesin (MSN) deficiency is a recently reported combined immunodeficiency, and few cases have been reported to date. We describe a Chinese patient with a novel mutation causing MSN deficiency and a novel phenotype. METHODS: Clinical and immunological data were collected. Whole-exome sequencing was performed to identify gene mutations. MSN protein expression and T cell proliferation and activation were determined by flow cytometry. Cell migration was confirmed with a Transwell assay. Autoantibody levels were analyzed using antigen microarrays. RESULTS: The patient was a 10-year-old boy who presented with recurrent fever, oral ulcers and dermatomyositis-like symptoms, such as periorbital edema, facial swelling, elevated creatine kinase levels, and abnormal electromyography and muscle biopsy results. Epstein-Barr virus (EBV) DNA was detected in the serum, cells and tissues of this patient. He further developed nasal-type NK/T-cell lymphoma. A novel hemizygous mutation (c.68 A > G, p.N23S) in the MSN gene was found. The immunological phenotype of this patient included persistent decreases in T and B lymphocyte counts but normal immunoglobulin IgG levels. The patient had attenuated MSN protein expression and impaired T-cell proliferation and migration. The proportions of Tfh cells and CD21low B cells in the patient were higher than those in the controls. Moreover, 82 IgG and 102 IgM autoantibodies were more abundant in the patient than in the healthy controls. CONCLUSIONS: The novel mutation N23S is pathogenic and leads to a severe clinical phenotype. EBV infection, tumor, and dermatomyositis-like autoimmune symptoms may be associated with MSN deficiency, further expanding the understanding of the disease.


Assuntos
Dermatomiosite , Infecções por Vírus Epstein-Barr , Proteínas dos Microfilamentos , Mutação , Humanos , Masculino , Infecções por Vírus Epstein-Barr/diagnóstico , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/imunologia , Dermatomiosite/genética , Dermatomiosite/diagnóstico , Dermatomiosite/imunologia , Criança , Proteínas dos Microfilamentos/genética , Mutação/genética , Herpesvirus Humano 4 , Sequenciamento do Exoma , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/diagnóstico , Autoanticorpos/sangue , Autoanticorpos/imunologia , Fenótipo , Linfócitos T/imunologia
5.
EMBO Rep ; 25(7): 3040-3063, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38849673

RESUMO

Polarized vesicular trafficking directs specific receptors and ion channels to cilia, but the underlying mechanisms are poorly understood. Here we describe a role for DLG1, a core component of the Scribble polarity complex, in regulating ciliary protein trafficking in kidney epithelial cells. Conditional knockout of Dlg1 in mouse kidney causes ciliary elongation and cystogenesis, and cell-based proximity labeling proteomics and fluorescence microscopy show alterations in the ciliary proteome upon loss of DLG1. Specifically, the retromer-associated protein SDCCAG3, IFT20, and polycystin-2 (PC2) are reduced in the cilia of DLG1-deficient cells compared to control cells. This phenotype is recapitulated in vivo and rescuable by re-expression of wild-type DLG1, but not a Congenital Anomalies of the Kidney and Urinary Tract (CAKUT)-associated DLG1 variant, p.T489R. Finally, biochemical approaches and Alpha Fold modelling suggest that SDCCAG3 and IFT20 form a complex that associates, at least indirectly, with DLG1. Our work identifies a key role for DLG1 in regulating ciliary protein composition and suggests that ciliary dysfunction of the p.T489R DLG1 variant may contribute to CAKUT.


Assuntos
Proteínas de Transporte , Cílios , Proteína 1 Homóloga a Discs-Large , Canais de Cátion TRPP , Animais , Cílios/metabolismo , Canais de Cátion TRPP/metabolismo , Canais de Cátion TRPP/genética , Camundongos , Proteína 1 Homóloga a Discs-Large/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Transporte/genética , Humanos , Transporte Proteico , Camundongos Knockout , Rim/metabolismo , Células Epiteliais/metabolismo , Ligação Proteica , Refluxo Vesicoureteral/metabolismo , Refluxo Vesicoureteral/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Anormalidades Urogenitais
6.
Surg Endosc ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38902410

RESUMO

BACKGROUND: With the improvements in laparoscopic or robotic surgical techniques and instruments, a growing number of surgeons have attempted to complete all digestive tract reconstruction intracorporeally; these procedures include totally robotic gastrectomy (TRG) and totally laparoscopic gastrectomy (TLG). This study aimed to evaluate the safety and feasibility of the TRG and compare the short-term outcomes of the TRG and TLG in patients with gastric cancer. METHODS: Between January 2018 and June 2023, 346 consecutive patients who underwent TRG or TLG at a high-volume academic gastric cancer specialty center were included. 1:1 propensity score matching (PSM) was performed to reduce confounding bias. The surgical outcomes, postoperative morbidity, and surgical burden were compared in PSM cohort. RESULTS: After PSM, a well-balanced cohort of 194 patients (97 in each group) was included in the analysis. The total operation time of the TRG group was significantly longer than that of the TLG group (244.9 vs. 213.0 min, P < 0.001). There was no significant difference in the effective operation time between the 2 groups (217.8 vs. 207.2 min, P = 0.059). The digestive tract reconstruction time of the TRG group was significantly shorter than that of the TLG group (39.4 vs. 46.7 min, P < 0.001). The mean blood loss in the TRG group was less than that in the TLG group (101.1 vs. 126.8 mL, P = 0.014). The TRG group had more retrieved lymph nodes in the suprapancreatic area than that in the TLG group (16.6 vs 14.2, P = 0.002). The TRG group had a lower surgery task load index (38.9 vs. 43.1, P < 0.001) than the TLG group. No significant difference was found in terms of postoperative morbidity between the 2 groups (14.4% vs. 16.5%, P = 0.691). CONCLUSION: This study demonstrated that TRG is a safe and feasible procedure, and is preferable to TLG in terms of invasion and ergonomics. The TRG may maximize the superiority of robotic surgical systems and embodies the theory of minimally invasive surgery.

7.
bioRxiv ; 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38853855

RESUMO

Psychological states can regulate intestinal mucosal immunity by altering the gut microbiome. However, the link between the brain and microbiome composition remains elusive. We show that Brunner's glands in the duodenal submucosa couple brain activity to intestinal bacterial homeostasis. Brunner's glands mediated the enrichment of gut probiotic species in response to stimulation of abdominal vagal fibers. Cell-specific ablation of the glands triggered transmissible dysbiosis associated with an immunodeficiency syndrome that led to mortality upon gut infection with pathogens. The syndrome could be largely prevented by oral or intra-intestinal administration of probiotics. In the forebrain, we identified a vagally-mediated, polysynaptic circuit connecting the glands of Brunner to the central nucleus of the amygdala. Intra-vital imaging revealed that excitation of central amygdala neurons activated Brunner's glands and promoted the growth of probiotic populations. Our findings unveil a vagal-glandular neuroimmune circuitry that may be targeted for the modulation of the gut microbiome. The glands of Brunner may be the critical cells that regulate the levels of Lactobacilli species in the intestine.

8.
Mol Genet Genomic Med ; 12(6): e2481, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38867642

RESUMO

PURPOSE: To characterize the phenotype and genotype of a Chinese family with autosomal-dominant retinitis pigmentosa (RP) accompanied by iris coloboma. METHODS: The proband, a 34-year-old male, was examined with his family by using fundus photography, optical coherence tomography (OCT), autofluorescence, and full-field electroretinography (ffERG). Genetic analyses were conducted through whole-exome sequencing (WES) to screen for variations. RESULTS: Three members of this Chinese family were shown to be bilateral iris coloboma. The male proband and his mother exhibited typical RP feature. The proband's late grandfather had been documented manifestation of iris coloboma. The mode of inheritance was confirmed to be autosomal dominance. Through linkage analysis and WES, a heterozygous variation in the miR-204 gene (n.37C>T), a noncoding RNA gene, was identified in these three members. CONCLUSIONS: In this third independent and the first Asian family, the existence of a miR-204 variant associated with RP accompanied by iris coloboma was confirmed. Our findings reinforce the significance of miR-204 as an important factor influencing visual function in the retina. When phenotypes like RP accompanied by iris coloboma in an autosomal-dominant pattern, including in Chinese patients, miR-204 aberrations should be considered.


Assuntos
Coloboma , MicroRNAs , Linhagem , Retinose Pigmentar , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Coloboma/genética , Coloboma/patologia , População do Leste Asiático , Iris/anormalidades , Iris/patologia , MicroRNAs/genética , Fenótipo , Retinose Pigmentar/genética
9.
Elife ; 122024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38921957

RESUMO

Accurate prediction of the structurally diverse complementarity determining region heavy chain 3 (CDR-H3) loop structure remains a primary and long-standing challenge for antibody modeling. Here, we present the H3-OPT toolkit for predicting the 3D structures of monoclonal antibodies and nanobodies. H3-OPT combines the strengths of AlphaFold2 with a pre-trained protein language model and provides a 2.24 Å average RMSDCα between predicted and experimentally determined CDR-H3 loops, thus outperforming other current computational methods in our non-redundant high-quality dataset. The model was validated by experimentally solving three structures of anti-VEGF nanobodies predicted by H3-OPT. We examined the potential applications of H3-OPT through analyzing antibody surface properties and antibody-antigen interactions. This structural prediction tool can be used to optimize antibody-antigen binding and engineer therapeutic antibodies with biophysical properties for specialized drug administration route.


Assuntos
Regiões Determinantes de Complementaridade , Aprendizado Profundo , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/imunologia , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Modelos Moleculares , Conformação Proteica , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/imunologia , Humanos
10.
Nat Commun ; 15(1): 4493, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38802342

RESUMO

Abscisic acid (ABA) plays a crucial role in promoting plant stress resistance and seed dormancy. However, how ABA regulates rice quality remains unclear. This study identifies a key transcription factor SLR1-like2 (SLRL2), which mediates the ABA-regulated amylose content (AC) of rice. Mechanistically, SLRL2 interacts with NF-YB1 to co-regulate Wx, a determinant of AC and rice quality. In contrast to SLR1, SLRL2 is ABA inducible but insensitive to GA. In addition, SLRL2 exhibits DNA-binding activity and directly regulates the expression of Wx, bHLH144 and MFT2. SLRL2 competes with NF-YC12 for interaction with NF-YB1. NF-YB1 also directly represses SLRL2 transcription. Genetic validation supports that SLRL2 functions downstream of NF-YB1 and bHLH144 in regulating rice AC. Thus, an NF-YB1-SLRL2-bHLH144 regulatory module is successfully revealed. Furthermore, SLRL2 regulates rice dormancy by modulating the expression of MFT2. In conclusion, this study revealed an ABA-responsive regulatory cascade that functions in both rice quality and seed dormancy.


Assuntos
Ácido Abscísico , Regulação da Expressão Gênica de Plantas , Oryza , Dormência de Plantas , Proteínas de Plantas , Oryza/genética , Oryza/metabolismo , Ácido Abscísico/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Dormência de Plantas/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Fator de Ligação a CCAAT/metabolismo , Fator de Ligação a CCAAT/genética , Sementes/metabolismo , Sementes/crescimento & desenvolvimento , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Amilose/metabolismo , Grão Comestível/metabolismo , Grão Comestível/genética , Plantas Geneticamente Modificadas
11.
Heliyon ; 10(10): e31062, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38803894

RESUMO

Common complications following laparoscopic appendectomy include wound infection, bleeding, intra-abdominal abscess, small bowel obstruction, stump leakage, and stump appendicitis. Here, we presented a case reporting detailing a rare complication following laparoscopic appendectomy: the development of a metastatic neck abscess induced by Klebsiella pneumoniae(K. pneumoniae). A 49-year-old male underwent emergency laparoscopic surgery with prophylactic antibiotic administration for acute appendicitis. Subsequently, he experienced persistent neck pain and fever postoperatively, prompting further investigation. Pus and blood cultures revealed K. pneumoniae, with magnetic resonance imaging confirming the presence of a neck abscess. Antibiotic therapy was adjusted, and surgical drainage of the abscess was performed after multidisciplinary consultation. The patient was discharged without complications. While rare, metastatic abscesses following appendectomy warrant consideration, particularly in K. pneumoniae infections. Comprehensive clinical assessment, imaging, and laboratory evaluation are crucial for timely diagnosis and management of such complications.

13.
J Clin Immunol ; 44(4): 102, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38634985

RESUMO

PURPOSE: Autoimmunity is a significant feature of APDS1 patients. We aimed to explore the pathogenic immune phenotype and possible mechanisms of autoimmunity in APDS1 patients. METHODS: The clinical records and laboratory data of 42 APDS1 patients were reviewed. Immunophenotypes were evaluated by multiparametric flow cytometry. Autoantibodies were detected via antigen microarray analysis. RESULTS: A total of 42 children with PIK3CD gene mutations were enrolled. Immunological tests revealed increased proportions of effector memory cells (86%) and central memory cells (59%) among CD4+ T cells; increased proportions of effector memory cells (83%) and terminally differentiated effector memory T cells (38%) among CD8+ T cells. Fewer CD3+ T cells and B cells and higher IgG levels were reported in patients with autoimmunity. The proportion of Tregs was decreased, and the proportions of Th9, Tfh, and Tfr cells were increased in APDS1 patients. Among APDS1 patients, higher proportion of Th2 and Tfr cells were found in those with autoimmunity. The proportions of CD11c+ B and CD21lo B cells in patients with autoimmunity were significantly increased. Antigen microarray analysis revealed a wide range of IgG/IgM autoantibodies in patients with APDS1. In patients with autoimmunity, the proportion of Tfr might be positively correlated with autoantibodies. CONCLUSIONS: The pathogenic immune phenotype of APDS1 patients included (1) deceased CD3+ T-cell and B-cell counts and increased IgG levels in patients with autoimmunity, (2) an imbalanced T helper cell subset, (3) increased proportions of autoreactive B cells, and (4) distinct autoantibody reactivities in patients with autoimmunity.


Assuntos
Autoanticorpos , Autoimunidade , Criança , Humanos , Linfócitos B , Fenótipo , Síndrome , Imunoglobulina G
14.
Heliyon ; 10(6): e28172, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38560664

RESUMO

The MTCH2 protein is located on the mitochondrial outer membrane and regulates mitochondria-related cell death. This study set out to investigate the role of MTCH2 in the underlying pathophysiological mechanisms of breast cancer (BC). MTCH2 expression levels in BC were analyzed using bioinformatics prior to verification by cell lines in vitro. Experiments of over-expression and siRNA-mediated knockdown of MTCH2 were conducted to assess its biological functions, including its effects on cellular proliferation and cycle progression. Xenografts were utilised for in vivo study and signaling pathway alterations were examined to identify the mechanisms driven by MTCH2 in BC proliferation and cell-cycle regulation. MTCH2 was up-regulated in BC and correlated with patients' overall survival. Over-expression of MTCH2 promoted cellular proliferation and cycle progression, while silencing MTCH2 had the opposite effect. Xenograft experiments were utilised to confirm the in vitro cellular findings and it was identified that the PI3K/Akt signaling pathway was activated by MTCH2 over-expression and suppressed by its silencing. Moreover, the activation of IGF-1R rescued cellular growth and cycle arrest induced by MTCH2-silencing. Overall, this study reveals that expression of MTCH2 in BC is upregulated and potentiates cellular proliferation and cycle progression via the PI3K/Akt pathway.

15.
Phenomics ; 4(1): 81-89, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38605904

RESUMO

The immune system defends the body from infection and plays a vital role in a wide range of health conditions. Metabolism affects a series of physiological processes, including those linked to the function of human immune system. Cellular metabolism modulates immune cell activation and cytokine production. Understanding the relationship between metabolism and immune response has important implications for the development of immune-based therapeutics. However, the deployment of large-scale functional assays to investigate the metabolic regulation of immune response has been limited by the lack of standardized procedures. Here, we present a protocol for the analysis of immune response using standardized whole-blood stimulation with metabolism modulation. Diverse immune stimuli including pattern recognition receptor (PRR) ligands and microbial stimuli were incubated with fresh human whole blood. The metabolic inhibitors were used to modulate metabolic status in the immune cells. The variable immune responses after metabolic interventions were evaluated. We described in detail the main steps involved in the whole-blood stimulation and cytokines quantification, namely, collection and treatment of whole blood, preparation of samples and controls, cytokines detection, and stimulation with metabolic interventions. The metabolic inhibitors for anabolic pathways and catabolic pathways exert selective effects on the production of cytokines from immune cells. In addition to a robust and accurate assessment of immune response in cohort studies, the standardized whole-blood stimulation with metabolic regulation might provide new insights for modulating immunity. Supplementary Information: The online version contains supplementary material available at 10.1007/s43657-023-00114-0.

16.
Biotechnol J ; 19(4): e2300557, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38581092

RESUMO

The halogenase-based catalysis is one of the most environmentally friendly methods for the synthesis of halogenated products, among which flavin-dependent halogenases (FDHs) have attracted great interest as one of the most promising biocatalysts due to the remarkable site-selectivity and wide substrate range. However, the complexity of constructing the NAD+-NADH-FAD-FADH2 bicoenzyme cycle system has affected the engineering applications of FDHs. In this work, a coenzyme self-sufficient tri-enzyme fusion was constructed and successfully applied to the continuous halogenation of L-tryptophan. SpFDH was firstly identified derived from Streptomyces pratensis, a highly selective halogenase capable of generating 6-chloro-tryptophan from tryptophan. Then, using gene fusion technology, SpFDH was fused with glucose dehydrogenase (GDH) and flavin reductase (FR) to form a tri-enzyme fusion, which increased the yield by 1.46-fold and making the coenzymes self-sufficient. For more efficient halogenation of L-tryptophan, a continuous halogenation bioprocess of L-tryptophan was developed by immobilizing the tri-enzyme fusion and attaching it to a continuous catalytic device, which resulted in a reaction yield of 97.6% after 12 h reaction. An FDH from S. pratensis was successfully applied in the halogenation and our study provides a concise strategy for the preparation of halogenated tryptophan mediated by multienzyme cascade catalysis.


Assuntos
Halogenação , Triptofano , Coenzimas , Oxirredutases/genética , Oxirredutases/metabolismo , Flavinas/metabolismo
18.
BMC Plant Biol ; 24(1): 167, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38438916

RESUMO

BACKGROUND: Generating elite rice varieties with high yield and superior quality is the main goal of rice breeding programs. Key agronomic traits, including grain size and seed germination characteristics, affect the final yield and quality of rice. The RGA1 gene, which encodes the α-subunit of rice G-protein, plays an important role in regulating rice architecture, seed size and abiotic stress responses. However, whether RGA1 is involved in the regulation of rice quality and seed germination traits is still unclear. RESULTS: In this study, a rice mutant small and round grain 5 (srg5), was identified in an EMS-induced rice mutant library. Systematic analysis of its major agronomic traits revealed that the srg5 mutant exhibited a semi-dwarf plant height with small and round grain and reduced panicle length. Analysis of the physicochemical properties of rice showed that the difference in rice eating and cooking quality (ECQ) between the srg5 mutant and its wild-type control was small, but the appearance quality was significantly improved. Interestingly, a significant suppression of rice seed germination and shoot growth was observed in the srg5 mutant, which was mainly related to the regulation of ABA metabolism. RGA1 was identified as the candidate gene for the srg5 mutant by BSA analysis. A SNP at the splice site of the first intron disrupted the normal splicing of the RGA1 transcript precursor, resulting in a premature stop codon. Additional linkage analysis confirmed that the target gene causing the srg5 mutant phenotype was RGA1. Finally, the introduction of the RGA1 mutant allele into two indica rice varieties also resulted in small and round rice grains with less chalkiness. CONCLUSIONS: These results indicate that RGA1 is not only involved in the control of rice architecture and grain size, but also in the regulation of rice quality and seed germination. This study sheds new light on the biological functions of RGA1, thereby providing valuable information for future systematic analysis of the G-protein pathway and its potential application in rice breeding programs.


Assuntos
Oryza , Oryza/genética , Sementes/genética , Germinação/genética , Melhoramento Vegetal , Grão Comestível/genética , Proteínas de Ligação ao GTP
19.
Proc Natl Acad Sci U S A ; 121(12): e2316230121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38483987

RESUMO

Mutations in the PKD2 gene, which encodes the polycystin-2 (PC2, also called TRPP2) protein, lead to autosomal dominant polycystic kidney disease (ADPKD). As a member of the transient receptor potential (TRP) channel superfamily, PC2 functions as a non-selective cation channel. The activation and regulation of the PC2 channel are largely unknown, and direct binding of small-molecule ligands to this channel has not been reported. In this work, we found that most known small-molecule agonists of the mucolipin TRP (TRPML) channels inhibit the activity of the PC2_F604P, a gain-of-function mutant of the PC2 channel. However, two of them, ML-SA1 and SF-51, have dual regulatory effects, with low concentration further activating PC2_F604P, and high concentration leading to inactivation of the channel. With two cryo-electron microscopy (cryo-EM) structures, a molecular docking model, and mutagenesis results, we identified two distinct binding sites of ML-SA1 in PC2_F604P that are responsible for activation and inactivation, respectively. These results provide structural and functional insights into how ligands regulate PC2 channel function through unusual mechanisms and may help design compounds that are more efficient and specific in regulating the PC2 channel and potentially also for ADPKD treatment.


Assuntos
Rim Policístico Autossômico Dominante , Canais de Cátion TRPP , Humanos , Canais de Cátion TRPP/metabolismo , Rim Policístico Autossômico Dominante/tratamento farmacológico , Rim Policístico Autossômico Dominante/genética , Rim Policístico Autossômico Dominante/metabolismo , Microscopia Crioeletrônica , Simulação de Acoplamento Molecular , Canais Iônicos
20.
Sheng Wu Gong Cheng Xue Bao ; 40(3): 821-833, 2024 Mar 25.
Artigo em Chinês | MEDLINE | ID: mdl-38545980

RESUMO

(S)-1-(2-fluorophenyl) ethylamine plays a crucial role as a chiral building block in pharmaceutical synthesis. ω-transaminases are widely recognized as environmentally friendly and efficient catalysts for the preparation of chiral amines. In this study, we isolated a novel ω-transaminase, PfTA, from Pseudogulbenkiania ferrooxidans through gene mining in the NCBI database. By employing semi-rational design, we obtained a Y168R/R416Q variant with enhanced enzyme activity. This variant exhibited the ability to catalyze the synthesis of (S)-1-(2-fluorophenyl) ethylamine from 2-fluorophenone, achieving a yield of 83.58% and an enantioselectivity exceeding 99% after a 10 h reaction. Compared to the wild type, the specific enzyme activity of the Y168R/R416Q variant reached 47.04 U/mg, which represents an increase of 11.65 times. Additionally, the catalytic efficiency, as measured by kcat/Km, was increased by 20.9 times. Molecular docking and structural simulation analysis revealed that the primary factor contributing to the improved catalytic efficiency is the expansion of the enzyme's active pocket and the alleviation of steric hindrance.


Assuntos
Etilaminas , Transaminases , Transaminases/genética , Transaminases/química , Simulação de Acoplamento Molecular , Domínio Catalítico , Mutação
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