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1.
Nature ; 611(7934): 180-187, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36289327

RESUMO

Bestrophin-2 (BEST2) is a member of the bestrophin family of calcium-activated anion channels that has a critical role in ocular physiology1-4. Here we uncover a directional permeability of BEST2 to glutamate that heavily favours glutamate exit, identify glutamine synthetase (GS) as a binding partner of BEST2 in the ciliary body of the eye, and solve the structure of the BEST2-GS complex. BEST2 reduces cytosolic GS activity by tethering GS to the cell membrane. GS extends the ion conducting pathway of BEST2 through its central cavity and inhibits BEST2 channel function in the absence of intracellular glutamate, but sensitizes BEST2 to intracellular glutamate, which promotes the opening of BEST2 and thus relieves the inhibitory effect of GS. We demonstrate the physiological role of BEST2 in conducting chloride and glutamate and the influence of GS in non-pigmented ciliary epithelial cells. Together, our results reveal a novel mechanism of glutamate release through BEST2-GS.


Assuntos
Bestrofinas , Glutamato-Amônia Ligase , Ácido Glutâmico , Glutamina , Bestrofinas/metabolismo , Células Epiteliais/metabolismo , Glutamato-Amônia Ligase/metabolismo , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Corpo Ciliar/metabolismo , Membrana Celular/metabolismo , Cloretos/metabolismo
2.
N Engl J Med ; 390(16): 1467-1480, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38657244

RESUMO

BACKGROUND: Patients with relapsed or refractory hematologic cancers have a poor prognosis. Chimeric antigen receptor (CAR) T-cell therapy as a bridge to allogeneic hematopoietic stem-cell transplantation (HSCT) has the potential for long-term tumor elimination. However, pre-HSCT myeloablation and graft-versus-host disease (GVHD) prophylaxis agents have toxic effects and could eradicate residual CAR T cells and compromise antitumor effects. Whether the integration of CAR T-cell therapy and allogeneic HSCT can preserve CAR T-cell function and improve tumor control is unclear. METHODS: We tested a novel "all-in-one" strategy consisting of sequential CD7 CAR T-cell therapy and haploidentical HSCT in 10 patients with relapsed or refractory CD7-positive leukemia or lymphoma. After CAR T-cell therapy led to complete remission with incomplete hematologic recovery, patients received haploidentical HSCT without pharmacologic myeloablation or GVHD prophylaxis drugs. Toxic effects and efficacy were closely monitored. RESULTS: After CAR T-cell therapy, all 10 patients had complete remission with incomplete hematologic recovery and grade 4 pancytopenia. After haploidentical HSCT, 1 patient died on day 13 of septic shock and encephalitis, 8 patients had full donor chimerism, and 1 patient had autologous hematopoiesis. Three patients had grade 2 HSCT-associated acute GVHD. The median follow-up was 15.1 months (range, 3.1 to 24.0) after CAR T-cell therapy. Six patients remained in minimal residual disease-negative complete remission, 2 had a relapse of CD7-negative leukemia, and 1 died of septic shock at 3.7 months. The estimated 1-year overall survival was 68% (95% confidence interval [CI], 43 to 100), and the estimated 1-year disease-free survival was 54% (95% CI, 29 to 100). CONCLUSIONS: Our findings suggest that sequential CD7 CAR T-cell therapy and haploidentical HSCT is safe and effective, with remission and serious but reversible adverse events. This strategy offers a feasible approach for patients with CD7-positive tumors who are ineligible for conventional allogeneic HSCT. (Funded by the National Natural Science Foundation of China and the Key Project of Science and Technology Department of Zhejiang Province; ClinicalTrials.gov numbers, NCT04599556 and NCT04538599.).


Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Imunoterapia Adotiva , Leucemia , Linfoma , Receptores de Antígenos Quiméricos , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Antígenos CD7 , Terapia Combinada , Doença Enxerto-Hospedeiro/prevenção & controle , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/métodos , Imunoterapia Adotiva/efeitos adversos , Imunoterapia Adotiva/métodos , Leucemia/terapia , Leucemia/mortalidade , Linfoma/mortalidade , Linfoma/terapia , Receptores de Antígenos Quiméricos/uso terapêutico , Indução de Remissão , Transplante Homólogo , Recidiva , Idoso
3.
Nature ; 592(7856): 763-767, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33762728

RESUMO

Systemic insulin sensitivity shows a diurnal rhythm with a peak upon waking1,2. The molecular mechanism that underlies this temporal pattern is unclear. Here we show that the nuclear receptors REV-ERB-α and REV-ERB-ß (referred to here as 'REV-ERB') in the GABAergic (γ-aminobutyric acid-producing) neurons in the suprachiasmatic nucleus (SCN) (SCNGABA neurons) control the diurnal rhythm of insulin-mediated suppression of hepatic glucose production in mice, without affecting diurnal eating or locomotor behaviours during regular light-dark cycles. REV-ERB regulates the rhythmic expression of genes that are involved in neurotransmission in the SCN, and modulates the oscillatory firing activity of SCNGABA neurons. Chemogenetic stimulation of SCNGABA neurons at waking leads to glucose intolerance, whereas restoration of the temporal pattern of either SCNGABA neuron firing or REV-ERB expression rescues the time-dependent glucose metabolic phenotype caused by REV-ERB depletion. In individuals with diabetes, an increased level of blood glucose after waking is a defining feature of the 'extended dawn phenomenon'3,4. Patients with type 2 diabetes with the extended dawn phenomenon exhibit a differential temporal pattern of expression of REV-ERB genes compared to patients with type 2 diabetes who do not have the extended dawn phenomenon. These findings provide mechanistic insights into how the central circadian clock regulates the diurnal rhythm of hepatic insulin sensitivity, with implications for our understanding of the extended dawn phenomenon in type 2 diabetes.


Assuntos
Ritmo Circadiano , Neurônios GABAérgicos/fisiologia , Resistência à Insulina , Fígado/fisiologia , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/fisiologia , Animais , Glicemia , Relógios Circadianos , Diabetes Mellitus Tipo 2 , Feminino , Glucose/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Fotoperíodo , Núcleo Supraquiasmático/citologia , Transmissão Sináptica
4.
Brief Bioinform ; 25(6)2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39322627

RESUMO

Short-tandem repeats (STRs) are the type of genetic markers extensively utilized in biomedical and forensic applications. Due to sequencing noise in nanopore sequencing, accurate analysis methods are lacking. We developed NASTRA, an innovative tool for Nanopore Autosomal Short Tandem Repeat Analysis, which overcomes traditional database-based methods' limitations and provides a precise germline analysis of STR genetic markers without the need for allele sequence reference. Demonstrating high accuracy in cell line authentication testing and paternity testing, NASTRA significantly surpasses existing methods in both speed and accuracy. This advancement makes it a promising solution for rapid cell line authentication and kinship testing, highlighting the potential of nanopore sequencing for in-field applications.


Assuntos
Algoritmos , Repetições de Microssatélites , Sequenciamento por Nanoporos , Sequenciamento por Nanoporos/métodos , Humanos , Marcadores Genéticos , Análise de Sequência de DNA/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Alelos
5.
J Biol Chem ; : 107798, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39307309

RESUMO

The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play a crucial role in regulating neuronal excitability. Despite growing evidence supporting the therapeutic potential of HCN1 inhibition in treating neurological disorders, the structural basis of channel inhibition by inhibitor has remained elusive. Here, we present the cryo-electron microscopy structure of human HCN1 channel in complex with inhibitor ivabradine, the drug on the market that acts on HCN channels. Combining electrophysiology, mutagenesis, and molecular dynamics simulations, our findings reveal that ivabradine binds to a previously unidentified pocket formed between the S4, S1, and HCN domain. Furthermore, through structure-based virtual screening, we identify two FDA-approved drugs that can inhibit the HCN1 channel by interacting with the ivabradine-binding site. Our results not only provide insights into the structural intricacies of ivabradine-mediated inhibition, but also offer a potential pharmacological framework for developing novel drugs targeting the HCN1 channel. The elucidation of these molecular interactions serves as a foundational step in advancing therapeutic strategies for modulating HCN1 activity, contributing to the broader landscape of drug discovery and development in this area.

6.
J Biol Chem ; 300(2): 105654, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38237680

RESUMO

The mammalian SID-1 transmembrane family members, SIDT1 and SIDT2, are multipass transmembrane proteins that mediate the cellular uptake and intracellular trafficking of nucleic acids, playing important roles in the immune response and tumorigenesis. Previous work has suggested that human SIDT1 and SIDT2 are N-glycosylated, but the precise site-specific N-glycosylation information and its functional contribution remain unclear. In this study, we use high-resolution liquid chromatography tandem mass spectrometry to comprehensively map the N-glycosites and quantify the N-glycosylation profiles of SIDT1 and SIDT2. Further molecular mechanistic probing elucidates the essential role of N-linked glycans in regulating cell surface expression, RNA binding, protein stability, and RNA uptake of SIDT1. Our results provide crucial information about the potential functional impact of N-glycosylation in the regulation of SIDT1-mediated RNA uptake and provide insights into the molecular mechanisms of this promising nucleic acid delivery system with potential implications for therapeutic applications.


Assuntos
Proteínas de Transporte de Nucleotídeos , RNA , Humanos , Transporte Biológico , Glicosilação , Mamíferos/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Transporte de Nucleotídeos/metabolismo , RNA/metabolismo
7.
J Biol Chem ; 300(6): 107288, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38636662

RESUMO

HCN channels are important for regulating heart rhythm and nerve activity and have been studied as potential drug targets for treating depression, arrhythmia, nerve pain, and epilepsy. Despite possessing unique pharmacological properties, HCN channels share common characteristics in that they are activated by hyperpolarization and modulated by cAMP and other membrane lipids. However, the mechanisms of how these ligands bind and modulate HCN channels are unclear. In this study, we solved structures of full-length human HCN3 using cryo-EM and captured two different states, including a state without any ligand bound and a state with cAMP bound. Our structures reveal the novel binding sites for cholesteryl hemisuccinate in apo state and show how cholesteryl hemisuccinate and cAMP binding cause conformational changes in different states. These findings explain how these small modulators are sensed in mammals at the molecular level. The results of our study could help to design more potent and specific compounds to influence HCN channel activity and offer new therapeutic possibilities for diseases that lack effective treatment.


Assuntos
Microscopia Crioeletrônica , AMP Cíclico , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização , Humanos , Sítios de Ligação , AMP Cíclico/metabolismo , Células HEK293 , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/química , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/genética , Conformação Proteica
8.
Hepatology ; 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38466833

RESUMO

BACKGROUND AND AIMS: RAD51 recombinase (RAD51) is a highly conserved DNA repair protein and is indispensable for embryonic viability. As a result, the role of RAD51 in liver development and function is unknown. Our aim was to characterize the function of RAD51 in postnatal liver development. APPROACH AND RESULTS: RAD51 is highly expressed during liver development and during regeneration following hepatectomy and hepatic injury, and is also elevated in chronic liver diseases. We generated a hepatocyte-specific Rad51 deletion mouse model using Alb -Cre ( Rad51 -conditional knockout (CKO)) and Adeno-associated virus 8-thyroxine-binding globulin-cyclization recombination enzyme to evaluate the function of RAD51 in liver development and regeneration. The phenotype in Rad51 -CKO mice is dependent on CRE dosage, with Rad51fl/fl ; Alb -Cre +/+ manifesting a more severe phenotype than the Rad51fl/fl ; Alb -Cre +/- mice. RAD51 deletion in postnatal hepatocytes results in aborted mitosis and early onset of pathological polyploidization that is associated with oxidative stress and cellular senescence. Remarkable liver fibrosis occurs spontaneously as early as in 3-month-old Rad51fl/fl ; Alb -Cre +/+ mice. While liver regeneration is compromised in Rad51 -CKO mice, they are more tolerant of carbon tetrachloride-induced hepatic injury and resistant to diethylnitrosamine/carbon tetrachloride-induced HCC. A chronic inflammatory microenvironment created by the senescent hepatocytes appears to activate ductular reaction the transdifferentiation of cholangiocytes to hepatocytes. The newly derived RAD51 functional immature hepatocytes proliferate vigorously, acquire increased malignancy, and eventually give rise to HCC. CONCLUSIONS: Our results demonstrate a novel function of RAD51 in liver development, homeostasis, and tumorigenesis. The Rad51 -CKO mice represent a unique genetic model for premature liver senescence, fibrosis, and hepatocellular carcinogenesis.

9.
Plant Cell ; 34(7): 2638-2651, 2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35445713

RESUMO

In eukaryotes, three-dimensional (3D) chromatin architecture maintains genome stability and is important in regulating gene transcription. However, little is known about the mechanisms by which diverse ATP-dependent chromatin remodeling complexes regulate the 3D chromatin structure in plants. We examined the 3D chromatin structure within the ATPase subunit of the SWI/SNF, ISWI, INO80, and CHD remodeling complexes in wild-type (WT) and mutant Arabidopsis thaliana plants by combining high-throughput sequencing with in situ Hi-C, the enrichment of histone marks, nucleosome density, and gene expression. We found that compartment regions switched and compartmental strength was significantly weakened in all four enzyme mutants. Chromatin remodeling complexes differentially regulated the nucleosome distribution pattern and density within the switching compartments. Alterations of nucleosome distribution pattern and density were associated with a reduction in H3K27me3 levels in the chromatin remodeling enzyme mutants and led to compartment switching. Our data show that chromatin remodeling complexes regulate the linear nucleosome distribution pattern and density to promote H3K27me3 deposition, which in turn regulates 3D chromatin structure.


Assuntos
Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Cromatina/genética , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/genética , Histonas/metabolismo , Nucleossomos/genética , Nucleossomos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Cell Mol Life Sci ; 81(1): 237, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38795132

RESUMO

Ovarian endometriosis is a common gynecological disease, and one of its most significant symptoms is infertility. In patients with endometriosis, defects in endometrial decidualization lead to impaired endometrial receptivity and embryo implantation, thus affecting early pregnancy and women's desire to have children. However, the mechanisms underlying the development of endometriosis and its associated defective decidualization are unclear. We find that NEK2 expression is increased in the ectopic and eutopic endometrium of patients with endometriosis. Meanwhile, NEK2 interacts with FOXO1 and phosphorylates FOXO1 at Ser184, inhibiting the stability of the FOXO1 protein. Importantly, NEK2-mediated phosphorylation of FOXO1 at Ser184 promotes cell proliferation, migration, invasion and impairs decidualization. Furthermore, INH1, an inhibitor of NEK2, inhibits the growth of ectopic lesions in mouse models of endometriosis and promotes endometrial decidualization in mouse models of artificially induced decidualization. Taken together, these findings indicate that NEK2 regulates the development of endometriosis and associated disorders of decidualization through the phosphorylation of FOXO1, providing a new therapeutic target for its treatment.


Assuntos
Proliferação de Células , Endometriose , Endométrio , Proteína Forkhead Box O1 , Quinases Relacionadas a NIMA , Feminino , Endometriose/metabolismo , Endometriose/patologia , Proteína Forkhead Box O1/metabolismo , Proteína Forkhead Box O1/genética , Humanos , Animais , Fosforilação , Camundongos , Quinases Relacionadas a NIMA/metabolismo , Quinases Relacionadas a NIMA/genética , Endométrio/metabolismo , Endométrio/patologia , Movimento Celular , Decídua/metabolismo , Decídua/patologia , Adulto , Modelos Animais de Doenças
11.
Biochemistry ; 63(15): 1892-1900, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-38985857

RESUMO

The C-C motif chemokine receptor 8 (CCR8) is a class A G-protein-coupled receptor that has emerged as a promising therapeutic target in cancer and autoimmune diseases. In the present study, we solved the cryo-electron microscopy (cryo-EM) structure of the human CCR8-Gi complex in the absence of a ligand at 2.58 Å. Structural analysis and comparison revealed that our apo CCR8 structure undergoes some conformational changes and is similar to that in the CCL1-CCR8 complex structure, indicating an active state. In addition, the key residues of CCR8 involved in the recognition of LMD-009, a potent nonpeptide agonist, were investigated by mutating CCR8 and testing the calcium flux induced by LMD-009-CCR8 interaction. Three mutants of CCR8, Y1133.32A, Y1724.64A, and E2867.39A, showed a dramatically decreased ability in mediating calcium mobilization, indicating their key interaction with LMD-009 and key roles in activation. These structural and biochemical analyses enrich molecular insights into the agonism and activation of CCR8 and will facilitate CCR8-targeted therapy.


Assuntos
Microscopia Crioeletrônica , Receptores CCR8 , Humanos , Receptores CCR8/metabolismo , Receptores CCR8/química , Receptores CCR8/genética , Modelos Moleculares , Conformação Proteica , Cálcio/metabolismo , Células HEK293
12.
J Struct Biol ; 216(3): 108117, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39153560

RESUMO

The complement system is a complex network of proteins that plays a crucial role in the innate immune response. One important component of this system is the C5a-C5aR1 complex, which is critical in the recruitment and activation of immune cells. In-depth investigation of the activation mechanism as well as biased signaling of the C5a-C5aR1 system will facilitate the elucidation of C5a-mediated pathophysiology. In this study, we determined the structure of C5a-C5aR1-Gi complex at a high resolution of 3 Å using cryo-electron microscopy (Cryo-EM). Our results revealed the binding site of C5a, which consists of a polar recognition region on the extracellular side and an amphipathic pocket within the transmembrane domain. Furthermore, we found that C5a binding induces conformational changes of C5aR1, which subsequently leads to the activation of G protein signaling pathways. Notably, a key residue (M265) located on transmembrane helix 6 (TM6) was identified to play a crucial role in regulating the recruitment of ß-arrestin driven by C5a. This study provides more information about the structure and function of the human C5a-C5aR1 complex, which is essential for the proper functioning of the complement system. The findings of this study can also provide a foundation for the design of new pharmaceuticals targeting this receptor with bias or specificity.


Assuntos
Complemento C5a , Microscopia Crioeletrônica , Receptor da Anafilatoxina C5a , Microscopia Crioeletrônica/métodos , Humanos , Receptor da Anafilatoxina C5a/química , Receptor da Anafilatoxina C5a/metabolismo , Sítios de Ligação , Complemento C5a/química , Complemento C5a/metabolismo , Ligação Proteica , Transdução de Sinais , Conformação Proteica , Modelos Moleculares
13.
EMBO J ; 39(8): e102961, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32090361

RESUMO

Both metabolic switch from oxidative phosphorylation to glycolysis (OGS) and epithelial-mesenchymal transition (EMT) promote cellular reprogramming at early stages. However, their connections have not been elucidated. Here, when a chemically defined medium was used to induce early EMT during mouse reprogramming, a facilitated OGS was also observed at the same time. Additional investigations suggested that the two events formed a positive feedback loop via transcriptional activation, cooperated to upregulate epigenetic factors such as Bmi1, Ctcf, Ezh2, Kdm2b, and Wdr5, and accelerated pluripotency induction at the early stage. However, at late stages, by over-inducing glycolysis and preventing the necessary mesenchymal-epithelial transition, the two events trapped the cells at a new pluripotency state between naïve and primed states and inhibited further reprogramming toward the naïve state. In addition, the pluripotent stem cells at the new state have high similarity to epiblasts from E4.5 and E5.5 embryos, and have distinct characteristics from the previously reported epiblast-like or formative states. Therefore, the time-dependent cooperation between OGS and EMT in regulating pluripotency should extend our understanding of related fields.


Assuntos
Reprogramação Celular , Transição Epitelial-Mesenquimal/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Glicólise , Fosforilação Oxidativa , Células-Tronco Pluripotentes/metabolismo , Animais , Blastocisto , Feminino , Humanos , Camundongos , Camundongos Endogâmicos ICR , Regulação para Cima
14.
Biochem Biophys Res Commun ; 733: 150634, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39307110

RESUMO

BACKGROUND AND AIMS: Polycystic ovary syndrome (PCOS) is a hormonal disorder common among women of reproductive age, characterized by irregular menstrual periods, elevated levels of androgens, and polycystic ovaries, leading to various symptoms and complications such as infertility, metabolic issues, and increased risk of diabetes and heart disease. This study aimed to compare traditional histological methods and ultrasound imaging for consistency in identifying PCOS in a mouse model. The shortest time to construct the PCOS model using letrozole was determined. METHODS: Female C57/BL mice were randomly divided into three groups: Group A received normal saline and a regular diet; Group B received 1 mg/kg/day of letrozole with a regular diet; and Group C received 1 mg/kg/day of letrozole with a high-fat diet. All mice were administered letrozole by intragastric gavage daily for five weeks. The traditional identification method included measuring body weight, examining vaginal smears, monitoring the estrous cycle, measuring serum androgen levels, and performing H&E staining of ovarian tissues. The PCOS model was evaluated using ultrasound imaging to identify and monitor follicles. The significance of the difference between the traditional identification method and the ultrasonic method was calculated using the nonparametric McNemar test, and consistency between the two methods was assessed with the kappa-coefficient test. On this basis, the ultrasound imaging technology was used to monitor the model-making process for 2, 3 and 4 weeks, and to monitor the parameters of the ovary and follicles to judge the shortest time that gavage letrozole caused the appearance of vesicular follicles in the mouse ovary. RESULTS: The traditional identification method showed no PCOS phenotype in group A mice, while groups B and C showed multiple ovarian cystic follicles, indicating successful model induction. The ultrasound imaging results were consistent with the traditional method, showing no PCOS in group A and multiple cystic follicles in groups B and C. The McNemar test revealed no significant difference between the traditional and ultrasonic identification methods. The kappa-coefficient test assessed consistency, yielding a value of 0.903, indicating strong agreement between the methods. The ovarian area, diameter, and the number and diameter of cystic follicles were not significantly changed at two weeks in the letrozole group compared with the control group. At three weeks, there were significant increases in the number and in the diameter of vesicular follicles compared with control cells. At four weeks, the number and diameter, the maximum cross-sectional area and diameter of the ovary were significantly increased compared with the control group. CONCLUSIONS: The ultrasound and traditional methods provide consistent results for identifying PCOS in a mouse model. Construction of the PCOS model by letrozole gavage takes at least three weeks.

15.
BMC Plant Biol ; 24(1): 719, 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39069617

RESUMO

BACKGROUND: With the profound changes in the global climate, the issue of grassland degradation is becoming increasingly prominent. Grassland degradation poses a severe threat to the carbon cycle and carbon storage within grassland ecosystems. Additionally, it will adversely affect the sustainability of food production. The grassland ecosystem in the northwest region of Liaoning Province, China, is particularly vulnerable due to factors such as erosion from the northern Horqin Sandy Land, persistent arid climate, and issues related to overgrazing and mismanagement of grassland. The degradation issue is especially pronounced in this ecological environment. However, previous research on the carbon density of degraded grasslands in Northeast China has predominantly focused on Inner Mongolia, neglecting the impact on the grasslands in the northwest of Liaoning Province. Therefore, this experiment aims to assess the influence of grassland degradation intensity on the vegetation and soil carbon density in the northwest of Liaoning Province. The objective is to investigate the changes in grassland vegetation and soil carbon density resulting from different degrees of grassland degradation. METHODOLOGY: This study focuses on the carbon density of grasslands at different degrees of degradation in the northwest of Liaoning Province, exploring the variations in vegetation and soil carbon density under different levels of degradation. This experiment employed field sampling techniques to establish 100 × 100 m plots in grasslands exhibiting varying degrees of degradation. Six replications of 100 × 100 m plots per degradation intensity were sampled. Vegetation and soil samples were collected for analysis of carbon density. RESULTS: The results indicate that in the context of grassland degradation, there is a significant reduction in vegetation carbon density. Furthermore, it was found that root carbon density is the primary contributor to vegetation carbon density. In comparison to mildly degraded grasslands, moderately and severely degraded grasslands experience a reduction in vegetation carbon density by 25.6% and 52.6%, respectively. However, with regard to the impact of grassland degradation on soil carbon density, it was observed that while grassland degradation leads to a slight decrease in soil carbon density, there is no significant change in soil carbon density in the short term under the influence of grassland degradation. CONCLUSIONS: Therefore, grassland degradation has exerted a negative impact on aboveground vegetation carbon density, reducing the carbon storage of above-ground vegetation in grasslands. However, there was no significant effect on grassland soil carbon density.


Assuntos
Carbono , Pradaria , Solo , Solo/química , Carbono/metabolismo , China , Conservação dos Recursos Naturais , Poaceae/metabolismo , Ecossistema
16.
Artigo em Inglês | MEDLINE | ID: mdl-39086116

RESUMO

OBJECTIVES: To identify novel genetic elements facilitating the horizontal transfer of the oxazolidinone/phenicol resistance gene optrA and the pleuromutilin-lincosamide-streptogramin A resistance gene lsa(E) in Streptococcus suis. METHODS: The complete genomes of S. suis HB18 and two transconjugants were obtained using both the Illumina and Nanopore platforms. MICs were determined by broth microdilution. Inverse PCR was performed to identify circular forms of the novel unconventional circularizable structure (UCS), genomic island (GI) and integrative and conjugative element (ICE). Conjugation experiments assessed the transferability of optrA and lsa(E) genes in S. suis. RESULTS: S. suis HB18 carried a multiresistance gene cluster optrA-lsa(E)-lnu(B)-aphA-aadE-spw. This gene cluster, flanked by intact and truncated erm(B) in the same orientation, resided on a novel ICESsuHB18. Inverse PCR revealed the existence of a novel UCS, named UCS-optrA + lsa(E), which could excise the gene cluster optrA-lsa(E)-lnu(B)-aphA-aadE-spw and one copy of erm(B) from ICESsuHB18. Two transconjugants with different characteristics were obtained. In transconjugant T-JH-GI, UCS-optrA + lsa(E) excised from ICESsuHB18 inserted into the erm(B)-positive GI, designated GISsuHB18, generating the novel GISsuHB18-1. Meanwhile, in T-JH-ICE, genetic rearrangement events occurred in ICESsuHB18 and GISsuHB18, forming the novel ICESsuHB18-1. CONCLUSIONS: This is the first report demonstrating the functionally active UCS-optrA + lsa(E) excising from ICESsuHB18 and inserting into the erm(B)-positive GISsuHB18 during the conjugation process. The location of optrA and lsa(E) on a multiresistance UCS enhances its persistence and dissemination.

17.
Brief Bioinform ; 23(2)2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35211720

RESUMO

Whole genome sequencing (WGS) can provide insight into drug-resistance, transmission chains and the identification of outbreaks, but data analysis remains an obstacle to its routine clinical use. Although several drug-resistance prediction tools have appeared, until now no website integrates drug-resistance prediction with strain genetic relationships and species identification of nontuberculous mycobacteria (NTM). We have established a free, function-rich, user-friendly online platform for MTB WGS data analysis (SAM-TB, http://samtb.szmbzx.com) that integrates drug-resistance prediction for 17 antituberculosis drugs, detection of variants, analysis of genetic relationships and NTM species identification. The accuracy of SAM-TB in predicting drug-resistance was assessed using 3177 sequenced clinical isolates with results of phenotypic drug-susceptibility tests (pDST). Compared to pDST, the sensitivity of SAM-TB for detecting multidrug-resistant tuberculosis was 93.9% [95% confidence interval (CI) 92.6-95.1%] with specificity of 96.2% (95% CI 95.2-97.1%). SAM-TB also analyzes the genetic relationships between multiple strains by reconstructing phylogenetic trees and calculating pairwise single nucleotide polymorphism (SNP) distances to identify genomic clusters. The incorporated mlstverse software identifies NTM species with an accuracy of 98.2% and Kraken2 software can detect mixed MTB and NTM samples. SAM-TB also has the capacity to share both sequence data and analysis between users. SAM-TB is a multifunctional integrated website that uses WGS raw data to accurately predict antituberculosis drug-resistance profiles, analyze genetic relationships between multiple strains and identify NTM species and mixed samples containing both NTM and MTB. SAM-TB is a useful tool for guiding both treatment and epidemiological investigation.


Assuntos
Mycobacterium tuberculosis , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Análise de Dados , Resistência a Medicamentos , Filogenia , Sequenciamento Completo do Genoma/métodos
18.
J Transl Med ; 22(1): 275, 2024 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-38481248

RESUMO

BACKGROUND: The prognostic significance of myelofibrosis (MF) grade in patients with myelodysplastic syndrome (MDS) following an allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains elusive. METHODS: We retrospectively analyzed data from 153 patients with MDS who underwent allo-HSCT and divided the patients into the MF-0/1 (N = 119) and MF-2/3 (N = 34) cohorts to explore the impact of MF on outcomes of allo-HSCT. RESULTS: The 2-year rates of relapse, non-relapse mortality (NRM), overall survival (OS), and progression-free survival (PFS) were 10.9% (95% confidence interval [CI] 5.9%-17.7%), 16.3% (95% CI 10.2%-23.6%), 76.6% (95% CI 69.0%-85.1%), and 72.8% (95% CI 65.0%-81.5%) in the MF-0/1 cohort, and 16.9% (95% CI 5.8%-32.9%), 14.7% (95% CI 5.3%-28.7%), 71.8% (95% CI 57.6%-89.6%), and 68.4% (95% CI 53.6%-87.2%) in the MF-2/3 cohort, respectively. No significant difference in the outcomes of allo-HSCT was observed between the two cohorts. Both univariate and multivariate analyses confirmed that MF-2/3 in patients with MDS had no effect on the prognosis of transplantation. In addition, major/bidirectional ABO blood type between donors and recipients was an independent risk factor for OS (hazard ratio [HR], 2.55; 95% CI 1.25-5.21; P = 0.010) and PFS (HR, 2.21; 95% CI 1.10-4.42; P = 0.025) in the multivariate analysis. In the subgroup of patients diagnosed with MDS with increased blasts (MDS-IB), it was consistently demonstrated that the clinical outcomes of the MF-2/3 cohort were comparable with those of the MF-0/1 cohort. The risk factors for OS and PFS in patients with MDS-IB were non-complete remission at transplantation and major/bidirectional ABO blood type. CONCLUSIONS: In conclusion, MF grade had no significant effect on prognosis of allo-HSCT in patients diagnosed with MDS. Major/bidirectional ABO blood type should be carefully considered in the context of more than one available donor.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Síndromes Mielodisplásicas , Mielofibrose Primária , Humanos , Mielofibrose Primária/complicações , Mielofibrose Primária/terapia , Estudos Retrospectivos , Transplante Homólogo , Síndromes Mielodisplásicas/terapia
19.
J Med Virol ; 96(2): e29449, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38314919

RESUMO

Enterovirus C99 (EV-C99) is a newly identified EV serotype within the species Enterovirus C. Few studies on EV-C99 have been conducted globally. More information and research on EV-C99 are needed to assess its genetic characteristics, phylogenetic relationships, and associations with enteroviral diseases. Here, the phylogenetic characteristics of 11 Chinese EV-C99 strains have been reported. The full-length genomic sequences of these 11 strains show 79.4-80.5% nucleotide identity and 91.7-94.3% amino acid (aa) identity with the prototype EV-C99. A maximum likelihood phylogenetic tree constructed based on the entire VP1 coding region identified 13 genotypes (A-M), revealing a high degree of variation among the EV-C99 strains. Phylogeographic analysis showed that the Xinjiang Uygur Autonomous Region is an important source of EV-C99 epidemics in various regions of China. Recombination analysis revealed inter-serotype recombination events of 16 Chinese EV-C99 strains in 5' untranslated regions and 3D regions, resulting in the formation of a single recombination form. Additionally, the Chinese strain of genotype J showed rich aa diversity in the P1 region, indicating that the genotype J of EV-C99 is still going through variable dynamic changes. This study contributes to the global understanding of the EV-C99 genome sequence and holds substantial implications for the surveillance of EV-C99.


Assuntos
Infecções por Enterovirus , Enterovirus , Humanos , Enterovirus/genética , Filogenia , Infecções por Enterovirus/epidemiologia , China/epidemiologia , Genótipo , Genoma Viral
20.
Opt Express ; 32(2): 1231-1245, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38297679

RESUMO

Comprehensive optical imaging of the intensity, phase, and birefringent information of the biological sample is important because important physical or pathological changes always accompany the changes in multiple optical parameters. Current studies lack such a metric that can present the comprehensive optical property of the sample in one figure. In this paper, a polarization state synthesis tomography (PoST) method, which is based on the principle of polarization state coherent synthesis and demodulation, is proposed to achieve full-field tomographic imaging of the comprehensive information (i.e., intensity, phase, and birefringence) of the biological sample. In this method, the synthesis of the polarization state is achieved by the time-domain full-field low coherence interferometer, where the polarization states of the sample beam and the reference beam are set to be orthogonal for the synthesis of the polarization state. The synthesis of the polarization state enables two functions of the PoST system: (1) Depth information of the sample can be encoded by the synthesized polarization state because only when the optical path length difference between the two arms is within the coherence length, a new polarization state can be synthesized; (2) Since the scattering coefficient, refractive index and the birefringent property of the sample can modulate the intensity and phase of the sample beam, the synthesized polarization state is sensitive to all these three parameters and can provide the comprehensive optical information of the sample. In this work, the depth-resolved ability and the comprehensive optical imaging metric have been demonstrated by the standard samples and the onion cells, demonstrating the potential application value of this method for further investigation of the important physical or pathological process of the biological tissues.

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