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1.
Phys Rev E ; 109(3-2): 035303, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38632759

RESUMO

Real-world water wave fields exhibit significant nonlinear and nonisospectral characteristics, making it challenging to predict their evolution by relying solely on numerical simulation or exact solutions using integrable system theory. Hence, this paper introduces a fast and adaptive method of modal identification and prediction in nonisospectral water wave fields using the reduced-order nonlinear solution (RONS) scheme. Specifically, we discuss the coarse graining and mode extraction of wave field snapshots from the data-driven and physics-driven perspectives and utilize the RONS method for principle modal prediction of nonisospectral water wave fields. This is achieved by investigating the standard and nonisospectral Gardner system describing nonlinear water waves as a demonstration. Through detailed comparison and analysis, the fundamental solitary behaviors and dispersive effects in the Gardner system are discussed. Subsequently, a neighbor approximation is developed that combines the essences of symbolic precomputation and numerical computation in the RONS procedure, which exploits the locality of nonlinear interactions in water wave fields.

2.
J Cardiothorac Surg ; 19(1): 77, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38336747

RESUMO

BACKGROUND: Complete atrioventricular septal defect is a complicated congenital heart malformations, and surgical correction is the best treatment, the severe tricuspid stenosis is a rare long-term complication after the surgery. CASE PRESENTATION: We report a case with the complication of severe tricuspid stenosis 7 years after the surgical correction of complete atrioventricular septal defect in a child. Then the patient underwent tricuspid mechanical valve replacement, Glenn, atrial septostomy, and circumconstriction of the right pulmonary artery. CONCLUSIONS: The patient recovered successfully with good short-term.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Defeitos dos Septos Cardíacos , Criança , Humanos , Constrição Patológica/complicações , Seguimentos , Defeitos dos Septos Cardíacos/cirurgia
3.
Clin Transl Oncol ; 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38079088

RESUMO

BACKGROUND: The use of additional treatment after surgery for stage IIIC endometrial cancer (EC) according to the Federation of Gynecology and Obstetrics (FIGO) is still a topic of discussion. This meta-analysis examined the effects of sandwich treatment and sequential treatment on the survival of individuals diagnosed with stage IIIC EC. METHODS: We examined the literature from various databases regarding the overall survival (OS) and adverse effects of the two additional therapies following surgery in individuals diagnosed with stage IIIC EC. Revman 5.4.1 was utilized to combine hazard ratios (HR) and their corresponding 95% confidence intervals (95% CI) for OS and toxicities. RESULTS: The findings comprised of five retrospective investigations involving a combined total of 800 individuals. The patients who underwent sandwich treatment did not demonstrate a notable improvement in survival rates over a period of 3 years. Upon eliminating the impact of extensive samples, it was discovered that sandwich therapy exhibited a superior 5-year overall survival compared to patients receiving sequential therapy. The effectiveness of sandwich therapy was superior to sequential therapy in terms of a 3-year OS for non-endometrioid histology, although the outcome did not reach statistical significance. The toxicities of both treatments were similar. CONCLUSIONS: In terms of long-term survival, sandwich therapy was found to be more advantageous than sequential therapy for patients with stage IIIC EC, with no significant disparity observed in the 3-year OS and toxicities between the two treatments. Sandwich therapy exhibited a tendency towards improved effectiveness in patients with histology other than endometrioid.

4.
J Relig Health ; 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37493816

RESUMO

This study aimed to investigate the association of religious belief on the postoperative psychological status and quality of life of parents of children with congenital heart disease (CHD). This was a cross-sectional study conducted at a provincial children's hospital in Fujian Province, China. Parents of postoperative children with CHD in the early postoperative period were included in this study between January 2020 and September 2020. The parents were divided into a religious belief group (n = 39) and a nonreligious belief group (n = 42) depending on whether they had religious beliefs. The Religious Coping Questionnaire, WHOQOL-BREF scale, Self-rating depression scale (SDS), and Self-rating anxiety scale (SAS) were used to evaluate psychological status and quality of life. The results showed that the SDS and SAS scores in the religious belief group were significantly lower than those in the nonreligious belief group (P = 0.012 and P = 0.003, respectively). The WHOQOL-BREF scale results showed that the religious belief group's score was significantly higher than those in the nonreligious belief group on the subscale scores of physiology, psychology, social relations, and environment on the WHOQOL-BREF. The total score of quality of life in the religious belief group was significantly higher than that in the nonreligious belief group. Religious belief was associated with lower SDS score (ß = - 0.324, P = 0.005) and SAS score (ß = - 0.245, P = 0.026), while religious belief was positively correlated with the score of WHOQOL-BREF (ß = 0.506, P < 0.001). In this study, we concluded that comparing to those with no religious beliefs, parents with religious belief experienced more positive emotions and higher quality of life when taking care of children in the early postoperative period after congenital heart surgery.

5.
BMC Pediatr ; 23(1): 73, 2023 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-36765306

RESUMO

BACKGROUND: To investigate health-related quality of life (HRQOL) in children with postoperative delirium (POD) after surgical repair of ventricular septal defects (VSDs). METHODS: A total of 109 patients were enrolled and assigned to the POD group (n = 47) and the non-POD group (n = 62). HRQOL was assessed by the PedsQLTM 3.0 Cardiac Module at discharge, and at the three- and six-month postoperative follow. RESULTS: Significant differences were detected in age, operation time, CPB time, mechanical ventilation duration, and length of ICU stay between the two groups, whereas sex and the VSD size did not significantly differ between groups. In terms of "cardiac heart problems and treatment" and "treatment-II", the HRQOL scores of the non-POD group were significantly better than those of the POD group. In terms of "perceived physical appearance" and "treatment anxiety", the POD group had significantly higher scores than the non-POD group at discharge and at the three-month postoperative follow-up. In terms of "cognitive problems" and "communication", the occurrence of POD still affected HRQOL at three months postoperatively, but the effect was significantly reduced at six months postoperatively. In terms of "total scores", both groups scored increasingly higher over time. The non-POD group had higher scores at discharge and three months postoperatively than the POD group, but no significant difference persisted at six months postoperatively. CONCLUSION: During the follow-up period, the HRQOL of the children with POD after surgical repair of VSD was inferior to that of the children without POD at discharge and three months postoperatively. However, the HRQOL did not differ between the two groups at six months postoperatively.


Assuntos
Delírio do Despertar , Comunicação Interventricular , Humanos , Criança , Qualidade de Vida/psicologia , Seguimentos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/epidemiologia , Comunicação Interventricular/cirurgia
6.
J Cardiothorac Surg ; 18(1): 66, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36755263

RESUMO

OBJECTIVE: This study aimed to investigate parents' understanding and attitudes toward using the WeChat platform for postoperative follow-up management of children with congenital heart disease (CHD). METHODS: A total of 196 children with CHD were followed up using the WeChat platform. A self-designed questionnaire was administered to their parents at discharge. RESULTS: Only 188 parents completed the questionnaire. One hundred nineteen parents (63.3%) confirmed that they heard about using the WeChat platform for postoperative follow-up, and 104 (87.4%) of them expressed that they were willing to accept the WeChat platform for their follow-up. A total of 42 parents (35.3%) were willing to undergo a follow-up of 1 to 3 months, and 32 (26.8%) were willing to undergo a long-term follow-up. Eighty parents (67.2%) had a positive attitude toward the effect of the WeChat platform on follow-up. Parents in rural areas and those educated at the middle school level or below were more willing to engage with the WeChat platform for postoperative follow-up management (P < 0.05). CONCLUSIONS: Although the WeChat platform is an essential tool for daily communication, its application in postoperative follow-up management is still under study. Most parents who participated in the follow-up study had a positive attitude toward the WeChat platform, especially those in rural areas and with lower education levels.


Assuntos
Cardiopatias Congênitas , Humanos , Criança , Seguimentos , Cardiopatias Congênitas/cirurgia , Escolaridade , Conhecimentos, Atitudes e Prática em Saúde , Pais/educação
7.
Cardiol Young ; 33(7): 1165-1171, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35912615

RESUMO

BACKGROUND: This study aimed to evaluate the efficacy and safety of high-frequency oscillation ventilation combined with intermittent mandatory ventilation in infants with acute respiratory distress syndrome after congenital heart surgery. METHODS: We retrospectively analysed the clinical data of 32 infants who were ventilated due to acute respiratory distress syndrome after congenital heart surgery between January, 2020 and January, 2022. We adopted high-frequency oscillation ventilation combined with intermittent mandatory ventilation as the rescue ventilation mode for infants who were failing conventional mechanical ventilation. RESULTS: After rescue high-frequency oscillation ventilation combined with intermittent mandatory ventilation, the dynamic compliance (Cdyn), PaO2 and PaO2/FiO2 ratio of the infants improved compared with conventional mechanical ventilation (p < 0.05). Moreover, high-frequency oscillation ventilation combined with intermittent mandatory ventilation resulted in a significant decrease in arterial-alveolar oxygen difference (AaDO2), FiO2, and oxygenation index (p < 0.05). No significant effect on haemodynamic parameters was observed. Moreover, no serious complications occurred in the two groups. CONCLUSION: Rescue high-frequency oscillation ventilation combined with intermittent mandatory ventilation significantly improved oxygenation in infants who failed conventional mechanical ventilation for acute respiratory distress syndrome after congenital heart surgery. Thus, this strategy is considered safe and feasible. However, further studies must be conducted to confirm the efficacy and safety of high-frequency oscillation ventilation combined with intermittent mandatory ventilation as a rescue perioperative respiratory support strategy for CHD.


Assuntos
Cardiopatias Congênitas , Ventilação de Alta Frequência , Síndrome do Desconforto Respiratório , Humanos , Lactente , Estudos Retrospectivos , Respiração Artificial/métodos , Cardiopatias Congênitas/cirurgia
8.
World J Clin Cases ; 10(25): 8906-8921, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36157636

RESUMO

BACKGROUND: Early quantitative assessment of liver fat content is essential for patients with fatty liver disease. Mounting evidence has shown that magnetic resonance (MR) technique has high accuracy in the quantitative analysis of fatty liver, and is suitable for monitoring the therapeutic effect on fatty liver. However, many packaging methods and postprocessing functions have puzzled radiologists in clinical applications. Therefore, selecting a quantitative MR imaging technique for patients with fatty liver disease remains challenging. AIM: To provide information for the proper selection of commonly used quantitative MR techniques to quantify fatty liver. METHODS: We completed a systematic literature review of quantitative MR techniques for detecting fatty liver, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Studies were retrieved from PubMed, Embase, and Cochrane Library databases, and their quality was assessed using the Quality Assessment of Diagnostic Studies criteria. The Reference Citation Analysis database (https:// www.referencecitationanalysis.com) was used to analyze citation of articles which were included in this review. RESULTS: Forty studies were included for spectroscopy, two-point Dixon imaging, and multiple-point Dixon imaging comparing liver biopsy to other imaging methods. The advantages and disadvantages of each of the three techniques and their clinical diagnostic performances were analyzed. CONCLUSION: The proton density fat fraction derived from multiple-point Dixon imaging is a noninvasive method for accurate quantitative measurement of hepatic fat content in the diagnosis and monitoring of fatty liver progression.

9.
Front Pediatr ; 10: 990752, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36160769

RESUMO

Objective: To investigate the effect of short music videos on needs satisfaction and separation anxiety of the family members of children with congenital heart disease (CHD) in the cardiac intensive care unit (CICU) during the COVID-19 pandemic. Methods: Eighty-seven children's family members were divided into the study group and the control group between February 2020 and March 2021. During the COVID-19 pandemic, the participants in the control group were visited by telephone, while the participants in the study group used the TikTok short music video application and WeChat as communication tools. After the intervention, the critical care family needs inventory (CCFNI) and separation anxiety scale (SAS) for all participants were recorded and analyzed. Results: There were no statistically significant differences in general characteristics or preintervention data between the two groups. However, the two dimensions of the support scale and information scale of the CCFNI in the study group were significantly different from those in the control group after the intervention (P = 0.008, and P = 0.021, respectively). There were significant differences in the three dimensions of the SAS between the two groups (P = 0.004, P = 0.007, and P = 0.041, respectively). Conclusion: The visiting system of the ICU changed during the COVID-19 pandemic, and the use of the TikTok short music video application and WeChat was conducive to optimizing the CICU ward visiting process, reducing the separation anxiety of the family members of children in the CICU, and improving their needs satisfaction.

10.
Front Microbiol ; 13: 954538, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35992666

RESUMO

Background: Metagenomic next-generation sequencing (mNGS) has become a valuable diagnostic tool in clinical etiology detection due to its rapidity, accuracy, and high throughput. However, the role of this technology in the diagnosis and treatment of infants with severe pneumonia after congenital heart surgery is still unclear. Methods: We conducted a retrospective cohort study of infants with severe pneumonia after congenital heart surgery. Samples were collected from infants in the hospital's cardiac intensive care unit between January 2010 and January 2022. The conventional microbiological test (CMT) group consisted of patients who underwent routine microbiological examination, and the infants' bronchoalveolar lavage fluid was examined. The mNGS group consisted of patients who underwent mNGS and routine microbiological examinations. Results: The overall positive rate of mNGS was significantly higher than that of CMT (88.4 vs. 62.5%, P = 0.009). After receipt of the microbiological results, 30/43 (70%) patients in the mNGS group had a change in antibiotic use compared with 14/40 (35%) in the CMT group (P = 0.002). Subsequently, after adjusting the treatment plan according to the microbiological test results, the number of people with improved pulmonary infection in the mNGS group was significantly higher than that in the CMT group (63 vs. 28%, P < 0.05). In addition, the duration of invasive ventilation, length of CICU stay and total hospital length of stay in the mNGS group were significantly lower than those in the CMT group (P < 0.05). Conclusion: mNGS is a valuable tool to determine the etiology of infants with severe pneumonia after congenital heart disease surgery. It can significantly improve the sensitivity of pathogen detection, which can help determine appropriate antimicrobial drugs, improve the diagnostic accuracy of the disease, and improve outcomes.

11.
Heart Surg Forum ; 25(3): E437-E440, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35787768

RESUMO

Cardiac lipoma is rarely reported in the pediatric population. We reported a case of subepicardial lipoma of the posterior atrioventricular sulcus in a child. The tumor was resected successfully and the patient recovered well after the operation.


Assuntos
Neoplasias Cardíacas , Lipoma , Criança , Coração , Neoplasias Cardíacas/diagnóstico , Neoplasias Cardíacas/patologia , Neoplasias Cardíacas/cirurgia , Humanos , Lipoma/diagnóstico , Lipoma/cirurgia
12.
Mol Plant Pathol ; 23(10): 1538-1554, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35810316

RESUMO

Alternaria alternata can resist high levels of reactive oxygen species (ROS). The protective roles of autophagy or autophagy-mediated degradation of peroxisomes (termed pexophagy) against oxidative stress remain unclear. The present study, using transmission electron microscopy and fluorescence microscopy coupled with a GFP-AaAtg8 proteolysis assay and an mCherry tagging assay with peroxisomal targeting tripeptides, demonstrated that hydrogen peroxide (H2 O2 ) and nitrogen depletion induced autophagy and pexophagy. Experimental evidence showed that H2 O2 triggered autophagy and the translocation of peroxisomes into the vacuoles. Mutational inactivation of the AaAtg8 gene in A. alternata led to autophagy impairment, resulting in the accumulation of peroxisomes, increased ROS sensitivity, and decreased virulence. Compared to the wild type, ΔAaAtg8 failed to detoxify ROS effectively, leading to ROS accumulation. Deleting AaAtg8 down-regulated the expression of genes encoding an NADPH oxidase and a Yap1 transcription factor, both involved in ROS resistance. Deleting AaAtg8 affected the development of conidia and appressorium-like structures. Deleting AaAtg8 also compromised the integrity of the cell wall. Reintroduction of a functional copy of AaAtg8 in the mutant completely restored all defective phenotypes. Although ΔAaAtg8 produced wild-type toxin levels in axenic culture, the mutant induced a lower level of H2 O2 and smaller necrotic lesions on citrus leaves. In addition to H2 O2 , nitrogen starvation triggered peroxisome turnover. We concluded that ΔAaAtg8 failed to degrade peroxisomes effectively, leading to the accumulation of peroxisomes and the reduction of the stress response. Autophagy-mediated peroxisome turnover could increase cell adaptability and survival under oxidative stress and starvation conditions.


Assuntos
Alternaria , Macroautofagia , Autofagia/genética , Nitrogênio/metabolismo , Peroxissomos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Virulência/genética
13.
J Cardiothorac Vasc Anesth ; 36(10): 3847-3854, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35811277

RESUMO

OBJECTIVES: This study aimed to evaluate the effect of high-frequency oscillatory ventilation, (HFOV) combined with prone positioning, on oxygenation and pulmonary ventilation in infants with acute respiratory distress syndrome (ARDS) after congenital heart surgery. DESIGN: A randomized controlled trial. SETTING: A single-center study at a tertiary teaching hospital. PARTICIPANTS: Patients with postoperative ARDS after congenital heart disease were divided randomly into the following 2 groups: HFOV combined with prone position (HFOV-PP), and HFOV combined with supine position (HFOV-SP). INTERVENTIONS: The primary outcomes were the PaO2/FIO2 ratio and the oxygenation index after the intervention, and the secondary outcomes were respiratory variables, hemodynamics, complications, and other short-term outcomes. RESULTS: Sixty-five eligible infants with ARDS were randomized to either the HFOV-PP (n = 32) or HFOV-SP (n = 33) group. No significant difference in baseline data was found between the 2 groups (p > 0.05). Oxygenation was improved in both groups after HFOV intervention. Compared with the HFOV-SP group, the HFOV-PP group had significantly increased PaO2/FIO2 and oxygenation index and a shorter duration of invasive ventilation and length of cardiac intensive care unit stay. No serious complications occurred in the 2 groups. CONCLUSION: HFOV-PP significantly improved oxygenation in infants with ARDS after cardiac surgery and had no serious complications.


Assuntos
Cardiopatias Congênitas , Ventilação de Alta Frequência , Síndrome do Desconforto Respiratório , Cardiopatias Congênitas/cirurgia , Humanos , Lactente , Decúbito Ventral , Estudos Prospectivos , Síndrome do Desconforto Respiratório/diagnóstico , Síndrome do Desconforto Respiratório/etiologia , Síndrome do Desconforto Respiratório/terapia
14.
Plant Sci ; 323: 111372, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35863557

RESUMO

The dynamic alterations in cell wall (CW) biosynthesis play an essential role in physiological isolation during the plant somatic embryogenesis (SE). However, the mechanisms underlying the functions of cell wall-associated miRNAs (CW-miRNA) remain poorly understood in plant SE. Here, we have identified 36 distinct candidate miRNAs associated with CW biosynthesis from longan third-generation genome as well as miRNA transcriptome, and modified RLM-RACE validated four distinct miRNA, which specifically targeted four CW-related genes. More importantly, we found that the dlo-miR397a-antagomir significantly enhanced DlLAC7 expression and improved laccase activity. Interestingly, inhibition of dlo-miR397a increased CW lignin deposition and promoted the tightening of protodermal cell by miRNA-mimic technology during early SE. Moreover, overexpression of dlo-miR408-3p (dlo-miR408-3p-agomir) markedly decreased DlLAC12 expression. dlo-miR408-3p-agomir activated rapid cell division, thus promoting the globular embryo (GE) development, which might be due to high DNA synthesis activity in protoepidermal cells, rather than affecting lignin synthesis. The subcellular location also indicated that both DlLAC7 and DlLAC12 proteins were primarily localized in CW and regulated CW biosynthesis. Overall, our findings provided new insight on the molecular regulatory networks comprising various miRNAs associated with cell wall, and established that dlo-miR397a and dlo-miR408-3p played differential roles during early SE in longan. The findings also shed some light on the potential role of miRNA target DlLAC regulating in vivo embryonic development of plant.


Assuntos
MicroRNAs , Parede Celular/metabolismo , Desenvolvimento Embrionário , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lignina/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Técnicas de Embriogênese Somática de Plantas , Sapindaceae
15.
Front Cardiovasc Med ; 9: 961997, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36684591

RESUMO

Objective: The purpose of this study was to compare the changes in serum lactate between surgical repair and transthoracic device closure of ventricular septal defects (VSDs) in pediatric patients. Methods: This study was a retrospective analysis, and 314 pediatric patients with simple VSD from October 2019 to October 2021 were selected. The patients were divided into the S group (surgical repair) and the D group (transthoracic device closure). The serum lactate value at ICU admission and 6 h after operation, as well as the highest serum lactate value were collected, and the 6-h serum lactate clearance rate was calculated. Result: Through propensity score matching, 43 pairs of cases were successfully matched. Compared with the S group, the D group had a shorter operation duration, ventilation duration, and ICU duration, as well as a lower drainage volume and total hospitalization cost. There was no significant difference between the two groups in the initial and highest serum lactate values after VSD closure, while the 6-h serum lactate value in the D group was significantly lower than that in the S group, and the 6-h serum lactate clearance rate in the D group was five times faster than that in the S group. In addition, the 6-h serum lactate clearance rate in the S group was mainly related to the operation time, CPB time, and ventilation time, while the 6-h serum lactate clearance rate in the D group was only related to the operation time. Conclusion: The initial and highest serum lactate levels were not significantly different between surgical repair and transthoracic device closure of VSD, but the 6-h serum lactate clearance rate of device closure was five times faster than that of surgical repair.

16.
Front Microbiol ; 12: 645792, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34262533

RESUMO

Little is known about the roles of peroxisomes in the necrotrophic fungal plant pathogens. In the present study, a Pex6 gene encoding an ATPase-associated protein was characterized by analysis of functional mutations in the tangerine pathotype of Alternaria alternata, which produces a host-selective toxin. Peroxisomes were observed in fungal cells by expressing a mCherry fluorescent protein tagging with conserved tripeptides serine-lysing-leucine and transmission electron microscopy. The results indicated that Pex6 plays no roles in peroxisomal biogenesis but impacts protein import into peroxisomes. The number of peroxisomes was affected by nutritional conditions and H2O2, and their degradation was mediated by an autophagy-related machinery termed pexophagy. Pex6 was shown to be required for the formation of Woronin bodies, the biosynthesis of biotin, siderophores, and toxin, the uptake and accumulation of H2O2, growth, and virulence, as well as the Slt2 MAP kinase-mediated maintenance of cell wall integrity. Adding biotin, oleate, and iron in combination fully restored the growth of the pex6-deficient mutant (Δpex6), but failed to restore Δpex6 virulence to citrus. Adding purified toxin could only partially restore Δpex6 virulence even in the presence of biotin, oleate, and iron. Sensitivity assays revealed that Pex6 plays no roles in resistance to H2O2 and superoxide, but plays a negative role in resistance to 2-chloro-5-hydroxypyridine (a hydroxyl radical-generating compound), eosin Y and rose Bengal (singlet oxygen-generating compounds), and 2,3,5-triiodobenzoic acid (an auxin transport inhibitor). The diverse functions of Pex6 underscore the importance of peroxisomes in physiology, pathogenesis, and development in A. alternata.

17.
J Fungi (Basel) ; 6(4)2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33114679

RESUMO

In addition to the production of a host-selective toxin, the tangerine pathotype of Alternaria alternata must conquer toxic reactive oxygen species (ROS) in order to colonize host plants. The roles of a peroxin 6-coding gene (pex6) implicated in protein import into peroxisomes was functionally characterized to gain a better understanding of molecular mechanisms in ROS resistance and fungal pathogenicity. The peroxisome is a vital organelle involved in metabolisms of fatty acids and hydrogen peroxide in eukaryotes. Targeted deletion of pex6 had no impacts on the biogenesis of peroxisomes and cellular resistance to ROS. The pex6 deficient mutant (Δpex6) reduced toxin production by 40% compared to wild type and barely induce necrotic lesions on citrus leaves. Co-inoculation of purified toxin with Δpex6 conidia on citrus leaves, however, failed to fully restore lesion formation, indicating that toxin only partially contributed to the loss of Δpex6 pathogenicity. Δpex6 conidia germinated poorly and formed fewer appressorium-like structures (nonmelanized enlargement of hyphal tips) than wild type. Δpex6 hyphae grew slowly and failed to penetrate beyond the epidermal layers. Moreover, Δpex6 had thinner cell walls and lower viability. All of these defects resulting from deletion of pex6 could also account for the loss of Δpex6 pathogenicity. Overall, our results have demonstrated that proper peroxisome functions are of vital importance to pathogenesis of the tangerine pathotype of A. alternata.

18.
Microbiol Res ; 241: 126566, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33032167

RESUMO

The tangerine pathotype of Alternaria alternata affects many citrus cultivars, resulting in yield losses. The capability to produce the host-selective toxin and cell-wall-degrading enzymes and to mitigate toxic reactive oxygen species is crucial for A. alternata pathogenesis to citrus. Little is known about nutrient availability within citrus tissues to the fungal pathogen. In the present study, we assess the infectivity of a biotin deficiency mutant (ΔbioB) and a complementation strain (CP36) on citrus leaves to determine how biotin impacts A. alternata pathogenesis. Growth and sporulation of ΔbioB are highly dependent on biotin. ΔbioB retains its ability to acquire and transport biotin from the surrounding environment. Growth deficiency of ΔbioB can also be partially restored by the presence of oleic acid or Tween 20, suggesting the requirement of biotin in lipid metabolism. Experimental evidence indicates that de novo biotin biosynthesis is regulated by the NADPH oxidase, implicating in the production of H2O2, and is affected by the function of peroxisomes. Three genes involved in the biosynthesis of biotin are clustered and co-regulated by biotin indicating a transcriptional feedback loop activation. Infectivity assays using fungal mycelium reveal that ΔbioB cultured on medium without biotin fails to infect citrus leaves; co-inoculation with biotin fully restores infectivity. The CP36 strain re-expressing a functional copy of bioB displays wild-type growth, sporulation and virulence. Taken together, we conclude that the attainability or accessibility of biotin is extremely restricted in citrus cells. A. alternata must be able to synthesize biotin in order to utilize nutrients for growth, colonization and development within the host.


Assuntos
Alternaria/metabolismo , Alternaria/patogenicidade , Biotina/biossíntese , Citrus/microbiologia , Esporos Fúngicos/crescimento & desenvolvimento , Alternaria/genética , Biotina/deficiência , Biotina/genética , Metabolismo dos Lipídeos/fisiologia , NADPH Oxidases/metabolismo , Ácido Oleico/metabolismo , Peroxissomos/metabolismo , Doenças das Plantas/microbiologia , Polissorbatos/metabolismo , Espécies Reativas de Oxigênio/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-29941813

RESUMO

Phosphate-solubilizing bacteria (PSB) can promote plant growth by dissolving insoluble phosphate. Therefore, PSB may have the potential to improve the mobility of heavy metals in soils and enhance phytoextraction. This study isolated a few PSB strains that could dissolve CdCO3 and solid Cd in soil. Two typical PSB, namely, high- and low-Cd-mobilizing PSB (Pseudomonas fluorescens gim-3 and Bacillus cereus qh-35, respectively), were selected to analyze the metabolic profiles, metabolic pathways, and mechanisms of mobilization of insoluble Cd. A total of 34 metabolites secreted by the two PSB strains were identified. Gluconic acid was the main contributor to Cd dissolution (42.4%) in high-Cd-mobilizing PSB. By contrast, gluconic acid was not secreted in low-Cd-mobilizing PSB. Metabolic pathway analysis showed that gluconic acid was produced by the peripheral direct oxidation pathway. Hence, PSB with peripheral direct oxidation pathway were likely to have high-Cd-mobilizing capacity.


Assuntos
Bacillus cereus/fisiologia , Cádmio/química , Gluconatos/química , Pseudomonas fluorescens/fisiologia , Poluentes do Solo/química , Redes e Vias Metabólicas , Fosfatos/química , Solo , Microbiologia do Solo , Solubilidade
20.
Inorg Chem ; 57(3): 916-920, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29323484

RESUMO

A quaternary narrow-band-gap semiconductor, Ba2Cr4GeSe10, has been discovered by solid-state reaction. It features a new structure type and crystallizes in the triclinic space group P1̅ (No. 2). The featured 2D anionic layers are constructed by condensed CrSe6 octahedra that are stacking along the c axis, with dispersed GeSe4 tetrahedra and located Ba2+ cations forming these layers. The energy-band structure shows a clear separation between the region of electronic conduction and the zone of electronic insulation. Significantly, an undoped Ba2Cr4GeSe10 sample shows a desirable low thermal conductivity κT (0.51-0.87 W/m·K) and a high Seebeck coefficient S (351-404 µV/K) and reaches a ZT ≈ 0.08 at 773 K.

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