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1.
Cancer Innov ; 2(4): 265-282, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38089746

RESUMO

Background: Lung cancer (LC) is the leading cause of cancer-related deaths worldwide. Tumor marker (TM) detection can indicate the existence and growth of a tumor and has therefore been used extensively for diagnosing LC. Here, we conducted a bibliometric analysis to examine TM-related publications for LC diagnosis to illustrate the current state and future trends of this field, as well as to identify additional promising TMs with high sensitivity. Methods: Publications regarding TMs in LC diagnosis were downloaded from the Web of Science Core Collection. CiteSpace was applied to perform a bibliometric analysis of journals, cocitation authors, keywords, and references related to this field. VOSviewer was used to generate concise diagrams about countries, institutions, authors, and keywords. Changes in the TM research frontier were analyzed through citation burst detection. Results: A total of 990 studies were analyzed in this work. The collaboration network analysis revealed that the People's Republic of China, Yonsei University, and Molina R were the most productive country, institution, and scholar, respectively. Additionally, Molina R was the author with the most citations. The National Natural Science Foundation of China was the largest funding source. "Carcinoembryonic antigen (CEA) as tumor marker in lung cancer" was the top reference with the most citations, Lung Cancer was the core journal, and "serum tumor marker" experienced a citation burst over the past 5 years. Conclusion: This bibliometric analysis of TMs in LC diagnosis presents the current trends and frontiers in this field. We summarized the research status of this field and the methods to improve the diagnostic efficacy of traditional serum TMs, as well as provided new directions and ideas for improving the LC clinical detection rate. Priority should be given to the transformation of computer-assisted diagnostic technology for clinical applications. In addition, circulating tumor cells, exosomes, and microRNAs were the current most cutting-edge TMs.

2.
Curr Microbiol ; 80(8): 270, 2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37402963

RESUMO

The diversity and distribution of secretion systems in Klebsiella pneumoniae are unclear. In this study, the six common secretion systems (T1SS-T6SS) were comprehensively investigated in the genomes of 952 K. pneumoniae strains. T1SS, T2SS, type T subtype of T4SS, T5SS, and subtype T6SSi of T6SS were found. The findings indicated fewer types of secretion systems in K. pneumoniae than reported in Enterobacteriaceae, such as Escherichia coli. One conserved T2SS, one conserved T5SS, and two conserved T6SS were detected in more than 90% of the strains. In contrast, the strains displayed extensive diversity of T1SS and T4SS. Notably, T1SS and T4SS were enriched in the hypervirulent and classical multidrug resistance pathotypes of K. pneumoniae, respectively. The results expand the epidemiological knowledge of the virulence and transmissibility of pathogenic K. pneumoniae and contribute to identify the potential strains for safe applications.


Assuntos
Infecções por Klebsiella , Sistemas de Secreção Tipo IV , Humanos , Klebsiella pneumoniae/genética , Virulência/genética , Genoma Bacteriano/genética , Genômica , Antibacterianos
3.
Bioprocess Biosyst Eng ; 46(9): 1319-1330, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37403004

RESUMO

Although 1,3-propanediol (1,3-PD) is usually considered an anaerobic fermentation product from glycerol by Klebsiella pneumoniae, microaerobic conditions proved to be more conducive to 1,3-PD production. In this study, a genome-scale metabolic model (GSMM) specific to K. pneumoniae KG2, a high 1.3-PD producer, was constructed. The iZY1242 model contains 2090 reactions, 1242 genes and 1433 metabolites. The model was not only able to accurately characterise cell growth, but also accurately simulate the fed-batch 1,3-PD fermentation process. Flux balance analyses by iZY1242 was performed to dissect the mechanism of stimulated 1,3-PD production under microaerobic conditions, and the maximum yield of 1,3-PD on glycerol was 0.83 mol/mol under optimal microaerobic conditions. Combined with experimental data, the iZY1242 model is a useful tool for establishing the best conditions for microaeration fermentation to produce 1,3-PD from glycerol in K. pneumoniae.


Assuntos
Glicerol , Klebsiella pneumoniae , Fermentação , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Glicerol/metabolismo , Propilenoglicóis/metabolismo , Propilenoglicol/metabolismo
4.
Knee Surg Sports Traumatol Arthrosc ; 31(8): 3277-3283, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36899193

RESUMO

PURPOSE: The objective of this study was to clarify the clinical value of the posterior cruciate ligament index (PCLI) in anterior cruciate ligament (ACL) rupture, to explore the relationship between the PCLI and course of disease, and to identify the influencing factors of the PCLI. METHODS: The PCLI was defined a quotient of the X (the tibial and femoral PCL attachments) and the Y (the maximum perpendicular distance from X to the PCL). A total of 858 patients were enrolled in this case-control study, including 433 patients with ACL ruptures who were assigned to the experimental group and 425 patients with meniscal tears (MTs) who were allocated to the control group. Some patients in the experimental group have collateral ligament rupture (CLR). Information, such as the patient's age, sex, and course of disease, was recorded. All patients underwent magnetic resonance imaging (MRI) preoperatively, and the diagnosis was confirmed with the aid of arthroscopy. The PCLI and the depth of the lateral femoral notch sign (LFNS) were calculated based on the MRI findings, and the characteristics of the PCLI were explored. RESULTS: The PCLI in the experimental group (5.1 ± 1.6) was significantly smaller than that in the control group (5.8 ± 1.6) (P < 0.05). The PCLI gradually decreased with time and was only 4.8 ± 1.4 in patients in the chronic phase (P < 0.05). This change was not due to the decrease in X but rather the increase in Y. The results also showed that the PCLI was not related to the depth of the LFNS or injuries of other structures in the knee joint. Furthermore, when the optimal cut-off point of the PCLI was 5.2 (area under the curve = 71%), the specificity and the sensitivity were 84% and 67%, respectively, but the Youden index was just 0.3 (P < 0.05). CONCLUSION: The PCLI decreases due to the increase in Y instead of the decrease in X with time, especially in the chronic phase. The change in X in this process may be offset during imaging. In addition, there are fewer influencing factors that lead to changes in the PCLI. Therefore, it can be used as a reliable indirect sign of ACL rupture. However, it is difficult to quantify the diagnostic criteria of the PCLI in clinical practice. Thus, the PCLI as a reliable indirect sign of ACL rupture is associated with the course of knee joint injury, and it can be used to describe the instability of the knee joint. LEVELS OF EVIDENCE: III.


Assuntos
Lesões do Ligamento Cruzado Anterior , Traumatismos do Joelho , Ligamento Cruzado Posterior , Humanos , Ligamento Cruzado Posterior/lesões , Ligamento Cruzado Anterior/cirurgia , Estudos de Casos e Controles , Articulação do Joelho/cirurgia , Lesões do Ligamento Cruzado Anterior/diagnóstico , Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Traumatismos do Joelho/diagnóstico por imagem , Traumatismos do Joelho/patologia , Ruptura/diagnóstico por imagem , Ruptura/patologia , Imageamento por Ressonância Magnética/métodos
5.
Arch Orthop Trauma Surg ; 143(2): 927-934, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35230503

RESUMO

INTRODUCTION: The lateral femoral notch sign (LFNS) and the kissing contusion (KC) are two indirect signs of anterior cruciate ligament (ACL) injuries. They can be used to diagnose ACL injuries. MATERIALS AND METHODS: A total of 1000 patients were enrolled in this study, including 500 patients with ACL injuries who assigned to experimental group and 500 patients with meniscal tear (MT) who allocated to control group. All the patients underwent magnetic resonance imaging (MRI) preoperatively, and the diagnosis was confirmed with the aid of arthroscopy. The depth of LFNS and the presence of KC were determined on MRI findings. The relationship and characteristics between these two indicators was explored. RESULTS: The notch depth of lateral femoral condyle in the experimental group (0.99 ± 0.56 mm) was significantly greater than that in the control group (0.49 ± 0.28 mm) (P < 0.05). The positive rate of KC in the experimental group (183/500) was markedly higher than that in the control group (3/500) (P < 0.05). The values of notch depth in patients who had ACL rupture concomitant lateral MT injuries and medial collateral ligament (MCL) injuries were 1.12 ± 0.64 and 1.23 ± 0.74 mm, respectively, which were significantly higher than those in patients with only ACL injury (0.89 ± 0.49 mm) (P < 0.05). It also was revealed that when the optimal cut-off point of LFNS was 0.72 mm (area under the curve (AUC) = 81%), the values of specificity and sensitivity were 67% and 84%, respectively. For KC, the corresponding values were 36.6% and 99.4%, respectively. The diagnostic outcome of LFNS was not in agreement with that of KC, as there was a poor coincidence according to the Kappa coefficient (Kappa = 0.155 < 0.4, P = 0.035). CONCLUSION: The LFNS and KC have strong clinical significance in the diagnosis of ACL injuries. A deeper notch often indicates a more complex knee injury. Notch depth equal to 0.72 mm can be basically considered as the optimal cut-off point for LFNS in statistics.


Assuntos
Lesões do Ligamento Cruzado Anterior , Contusões , Traumatismos do Joelho , Humanos , Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Lesões do Ligamento Cruzado Anterior/cirurgia , Estudos de Casos e Controles , Ligamento Cruzado Anterior/cirurgia , Traumatismos do Joelho/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Contusões/diagnóstico por imagem , Contusões/patologia , Estudos Retrospectivos
6.
Curr Microbiol ; 79(8): 218, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35704098

RESUMO

In this study, to reduce the formation of organic acid during 1,3-propanediol biosynthesis in Klebsiella pneumoniae, a method combining UV mutagenesis and high-throughput screening with pH color plates was employed to obtain K. pneumoniae mutants. When compared with the parent strain, the total organic acid formation by the mutant decreased, whereas 1,3-propanediol biosynthesis increased after 24 h anaerobic shake flask culture. Subsequently, genetic changes in the mutant were analyzed by whole-genome sequencing and verified by signal gene deletion. Mutation of the rpoS gene was confirmed to contribute to the regulation of organic acid synthesis in K. pneumoniae. Besides, rpoS deletion eliminated the formation of 2,3-butanediol, the main byproduct produced during 1,3-propanediol fermentation, indicating the role of rpoS in metabolic regulation in K. pneumoniae. Thus, a K. pneumoniae mutant was developed, which could produce lower organic acid during 1,3-propanediol fermentation due to an rpoS mutation in this study.


Assuntos
Klebsiella pneumoniae , Propilenoglicóis , Butileno Glicóis/metabolismo , Fermentação , Glicerol/metabolismo , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Mutação , Propilenoglicóis/metabolismo
7.
Infect Genet Evol ; 100: 105275, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35339697

RESUMO

The exponential increase in the number of genomes deposited in public databases can help us gain a more holistic understanding of the phylogeny and epidemiology of Klebsiella pneumoniae. However, inferring the evolutionary relationships of K. pneumoniae based on big genomic data is challenging for existing methods. In this study, core genes of K. pneumoniae were determined and analysed in terms of differences in GC content, mutation rate, size, and potential functions. We then developed a stable genes-based method for big data analysis and compared it with existing methods. Our new method achieved a higher resolution phylogenetic analysis of K. pneumoniae. Using this genes-based method, we explored global phylogenetic relationships based on a public database of nearly 953 genomes. The results provide useful information to facilitate the phylogenetic and epidemiological analysis of K. pneumoniae, and the findings are relevant for security applications.


Assuntos
Infecções por Klebsiella , Klebsiella pneumoniae , Genoma Bacteriano , Genômica , Humanos , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/genética , Filogenia
8.
Indian J Orthop ; 56(5): 805-811, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35103026

RESUMO

Background: We investigated the effect of platelet-rich plasma (PRP) on tendon-bone healing and intra-articular graft (IAG) maturation after anterior cruciate ligament (ACL) reconstruction. Methods: In this prospective randomized controlled study, 60 patients with ruptured ACLs were divided one-to-one into two groups (study and control). Patients were treated using single-bundle autologous hamstring autografts. Only patients in the study group were administered PRP. Knee function (pre-operative and three-, six-, and 12-month post-operative Lysholm activity, Tegner and International Knee Documentation Committee scores, femoral tunnel (FT) and tibial tunnel (TT) diameters measured with computed tomography (post-operative follow-up at 4 days and at 12 months), and magnetic resonance imaging signal/noise quotients of the IAG and graft in the FT (at 12 months) were used to evaluate tendon-bone healing and graft maturation. Results: Patients' knee function scores improved after ACL reconstruction, but there were no significant differences between groups. At 12 months, FT (study, 8.88 ± 1.46 mm; control, 8.42 ± 2.75 mm) and TT (study, 9.50 ± 1.07 mm; control, 9.99 ± 1.91 mm) diameters were larger than FT (study, 6.91 ± 0.74 mm; control, 7.30 ± 1.17 mm) and TT (study, 9.31 ± 0.83 mm; control, 9.36 ± 0.88 mm) diameters at 4 days; however, differences between groups were not significant (FT, P = 0.67; TT, P = 0.52). There were no significant differences between groups for signal/noise quotients of the IAG (study, 1.38 ± 0.70; control, 2.01 ± 0.62; P = 0.06) and FT-portion of the graft (study, 2.39 ± 1.22; control, 2.46 ± 0.83; P = 0.89). Conclusion: PRP had no significant effect on reducing bone tunnel widening, accelerating tendon-bone healing, or improving knee function; however, PRP may improve IAG maturation. Trial registration: Our study was first registered at Clinicaltrials.gov with registration No. NCT04659447 on 12/09/2020.

9.
Front Surg ; 9: 1066304, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36684168

RESUMO

Background: Extraosseous Ewing's sarcoma/primary neuroectodermal tumor (EES/PNET) is a rare, malignant, small round blue cell tumor, which usually involves the larynx, kidneys, and esophagus. The most common metastatic sites are lung and bone. The incidence of epidural EES/PNET was 0.9%, and a detailed search of the PubMed literature found only 7 case reports of epidural ESS/PNET at the cervicothoracic junction in children. Case description: We report a case of epidural ESS/PNET at the cervicothoracic junction in a child with chest and back pain as the first symptom, which worsened after half a year and developed incomplete paralysis of both lower extremities and urinary incontinence. She underwent emergency surgery, chemotherapy and radiotherapy, and died of lung metastases 8 months after surgery. Conclusion: Primary epidural tumors are mostly benign, such as spinal meningiomas and neuromas. Contrary to what has been previously thought, we report a case of malignant epidural EES/PNET at the cervicothoracic junction without bone destruction; The rarity of epidural EES/PNET at the cervicothoracic junction in children has led to a lack of data, particularly on prognostic factors and recurrence patterns. Due to the difficulty of early diagnosis and high mortality, spine surgeons must explore and increase their awareness of this disease.

10.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 35(9): 1200-1204, 2021 Sep 15.
Artigo em Chinês | MEDLINE | ID: mdl-34523289

RESUMO

OBJECTIVE: To summarize the relationship between lateral femoral notch sign (LFNS) and anterior cruciate ligament (ACL) rupture. METHODS: The relevant literature of LFNS at home and abroad in recent years was retrospectively reviewed, and its mechanism, diagnostic criteria and influencing factors in diagnosis of ACL rupture were summarized and analyzed. RESULTS: The LFNS is associated with rotational stability of the knee. As an indirect sign of ACL rupture, the LFNS has high clinical diagnostic value, especially the diagnosis of ACL rupture with lateral meniscus injury. CONCLUSION: The diagnostic criteria and influencing factors of LFNS in diagnosis of ACL rupture are still unclear and controversial, which needs further study.


Assuntos
Lesões do Ligamento Cruzado Anterior , Reconstrução do Ligamento Cruzado Anterior , Ligamento Cruzado Anterior , Lesões do Ligamento Cruzado Anterior/diagnóstico , Lesões do Ligamento Cruzado Anterior/cirurgia , Humanos , Articulação do Joelho/cirurgia , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Ruptura/cirurgia
11.
J Microbiol Biotechnol ; 30(5): 753-761, 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32482942

RESUMO

To determine the role of pyruvate dehydrogenase complex (PDHC) in Klebsiella pneumoniae, the growth and metabolism of PDHC-deficient mutant in glycerol-based medium were analyzed and compared with those of other strains. Under aerobic conditions, the PDHC activity was fourfold higher than that of pyruvate formate lyase (PFL), and blocking of PDHC caused severe growth defect and pyruvate accumulation, indicating that the carbon flux through pyruvate to acetyl coenzyme A mainly depended on PDHC. Under anaerobic conditions, although the PDHC activity was only 50% of that of PFL, blocking of PDHC resulted in more growth defect than blocking of PFL. Subsequently, combined with the requirement of CO2 and intracellular redox status, it was presumed that the critical role of PDHC was to provide NADH for the anaerobic growth of K. pneumoniae. This presumption was confirmed in the PDHC-deficient mutant by further blocking one of the formate dehydrogenases, FdnGHI. Besides, based on our data, it can also be suggested that an improvement in the carbon flux in the PFL-deficient mutant could be an effective strategy to construct highyielding 1,3-propanediol-producing K. pneumoniae strain.


Assuntos
Meios de Cultura/metabolismo , Glicerol/metabolismo , Klebsiella pneumoniae , Complexo Piruvato Desidrogenase/genética , Acetiltransferases/metabolismo , Meios de Cultura/química , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Mutação/genética , Propilenoglicóis/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Ácido Pirúvico/metabolismo
12.
Curr Microbiol ; 77(1): 55-61, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31705389

RESUMO

Anaerobic growth defect of pyruvate formate lyase (PFL)-deficient Klebsiella pneumoniae limits its industrial application, and the reason for this growth defect was analyzed in this study. The obtained evidences, combined with normal intracellular redox status and no further inhibition by adhE deletion, strongly suggested that growth defect in PFL-deficient K. pneumoniae was probably caused by lack of carbon flux from pyruvate to acetyl-CoA (AcCoA). Correspondingly, the anaerobic growth of PFL-deficient K. pneumoniae was promoted by deletion of pdhR, a negative transcriptional regulator gene for AcCoA generation. Through the regulation of pdhR deletion, the PFL-deficient K. pneumoniae exhibited highly efficient 1,3-propanediol production. Besides, in a 2-L fed-batch fermentation process, the cell growth of PFL-deficient K. pneumoniae strain almost recovered, when compared with that of the normal strain, and the 1,3-propanediol yield increased by 14%, while the byproducts acetate and 2,3-butanediol contents decreased by 29% and 24%, respectively.


Assuntos
Acetiltransferases/metabolismo , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/metabolismo , Propilenoglicóis/metabolismo , Acetiltransferases/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Mutação/genética
13.
J Zhejiang Univ Sci B ; 20(4): 363-370, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30932381

RESUMO

OBJECTIVE: Anger attacks have been observed in patients with obsessive-compulsive disorder (OCD), often triggered by obsessional triggers. However, few studies have reported the clinical characteristics and correlates of anger attacks among Chinese patients with OCD. METHODS: A total of 90 adults with a primary diagnosis of OCD, ranging from 15 to 78 years old, participated in the study. Participants were administered the Rage Outbursts and Anger Rating Scale (ROARS), Yale-Brown Obsessive-Compulsive Scale-Second Edition, and Brown Assessment of Beliefs Scale by a trained clinician. Patients completed the Obsessive-Compulsive Inventory-Revised and Depression Anxiety Stress Scale-21. RESULTS: A total of 31.3% of participants reported anger outbursts in the past week, and ROARS scores had no significant correlation with age, duration of illness, OCD severity, depression, or stress. However, ROARS scores were negatively related to education level, and positively related to obsessing symptoms and anxiety. CONCLUSIONS: These data suggest that anger attacks are relatively common in Chinese patients with OCD. The severity of anger attacks is related to educational level, obsessing symptoms, and anxiety, which may be a latent variable reflecting executive functioning and emotion regulation skills.


Assuntos
Ira , Transtorno Obsessivo-Compulsivo/psicologia , Adolescente , Adulto , Fatores Etários , China , Depressão/complicações , Emoções , Função Executiva , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Transtorno Obsessivo-Compulsivo/complicações , Transtorno Obsessivo-Compulsivo/diagnóstico , Análise de Regressão , Índice de Gravidade de Doença , Estresse Psicológico , Adulto Jovem
14.
RSC Adv ; 9(67): 39090-39099, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-35540663

RESUMO

Contamination of microorganisms causes a rapid deterioration in the quality of fresh sturgeon meat, which results in the shortening of the shelf-life and increase in the health risk. In this paper, two preservation treatments based on microbial control were considered. During the chilling storage (0-6 days) period, the sensory analysis and the volatile compound (VOC) evaluation were performed by electronic nose and SPME-GC/MS. Results showed that washing with acidic oxidized electrolyzed water and the addition of ε-PL influences the sensitive VOCs of the fresh sturgeon by inhibiting the spoilage of microbes or introducing the chemical agents like free chlorine and reactive oxygen species. Furthermore, GC/MS analysis detected more than 40 kinds of VOCs, mainly aldehydes and ketones, in the fresh sturgeon during the chilling storage period. The relative content of heptanal, nonanal, and acetophenone increased linearly with the storage time in all the groups, where R 2 of all the groups was larger than 0.9. However, the content of hexanal and octanal decreased simultaneously. This indicated that the present work discovered the potential biomarkers acting as indicators for rapidly evaluating the quality of sturgeon products.

15.
Biotechnol Appl Biochem ; 65(6): 857-864, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30063071

RESUMO

NADH:quinone oxidoreductases (NQOs) act as the electron entry sites in bacterial respiration and oxidize intracellular NADH that is essential for the synthesis of numerous molecules. Klebsiella pneumoniae contains three NQOs (NDH-1, NDH-2, and NQR). The effects of inactivating these NQOs, separately and together, on cell metabolism were investigated under different culture conditions. Defective growth was evident in NDH-1-NDH-2 double and NDH-1-NDH-2-NQR triple deficient mutants, which was probably due to damage to the respiratory chain. The results also showed that K. pneumoniae can flexibly use NQOs to maintain normal growth in single NQO-deficient mutants. And more interestingly, under aerobic conditions, inactivating NDH-1 resulted in a high intracellular NADH:NAD+ ratio, which was proven to be beneficial for 2,3-butanediol production. Compared with the parent strain, 2,3-butanediol production by the NDH-1-deficient mutant was increased by 46% and 62% in glycerol- and glucose-based media, respectively. Thus, our findings provide a practical strategy for metabolic engineering of respiratory chains to promote the biosynthesis of 2,3-butanediol in K. pneumoniae.


Assuntos
Klebsiella pneumoniae/crescimento & desenvolvimento , Klebsiella pneumoniae/metabolismo , Engenharia Metabólica , Quinona Redutases/antagonistas & inibidores , Quinona Redutases/deficiência , Butileno Glicóis/química , Butileno Glicóis/metabolismo , Klebsiella pneumoniae/citologia , Klebsiella pneumoniae/enzimologia , Quinona Redutases/genética , Quinona Redutases/metabolismo
16.
J Appl Microbiol ; 123(3): 678-687, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28637087

RESUMO

AIMS: To investigate the role of phosphoenolpyruvate (PEP) carboxylation in cell metabolism in Klebsiella pneumoniae. METHODS AND RESULTS: The effects of deleting pck, which encodes PEP carboxykinase (PCK), and/or ppc, which encodes PEP carboxylase (PPC), on growth, enzyme activity and metabolite formation of Kl. pneumoniae were investigated. A self-regulatory mechanism of PEP carboxylation was found in ppc- or pck-deficient mutants, which resulted in almost no change in succinate formation. However, almost no growth was observed in a ppc- and pck-deficient mutant. Interestingly, only deleting pck affected the energy metabolism and promoted aerobic cell growth. Under micro-aerobic conditions, although there was only a small (8·1%) increase of 1,3-propanediol production by such pck-deficient mutant during a 2-l fed-batch process, the by-products 2,3-butanediol and acetate significantly decreased by 73·0% and 54·8%, respectively, compared with those in the parent strain. CONCLUSIONS: PEP carboxylation could be a critical anaplerotic reaction for converting C3 to C4 metabolites in the central metabolism of Kl. pneumoniae. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to identify the critical role of PEP carboxylation, as well as those of PPC and PCK, which are responsible for this reaction, in Kl. pneumoniae. In addition, the pck-deficient mutant was proven to be a valuable 1,3-propanediol producer.


Assuntos
Proteínas de Bactérias/genética , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/crescimento & desenvolvimento , Fosfoenolpiruvato Carboxilase/genética , Propilenoglicóis/metabolismo , Proteínas de Bactérias/metabolismo , Butileno Glicóis/metabolismo , Fermentação , Deleção de Genes , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Fosfoenolpiruvato Carboxilase/metabolismo , Ácido Succínico/metabolismo
17.
Biotechnol Appl Biochem ; 63(5): 734-739, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26234465

RESUMO

Much effort has been devoted to the metabolic engineering of Klebsiella pneumoniae; however, our knowledge of the actual expression level of promoters used in K. pneumoniae is limited. In this study, the expression levels of three promoters were compared systematically by using the lacZ reporter gene with different carbon sources in K. pneumoniae. The results showed that, although promoters PT5 and Ptac designed for Escherichia coli were functional, PT5 appeared more efficient and the induction/repression ratio of Ptac was decreased extremely in K. pneumoniae. The basal level of Ptac for lacZ expression reached 396.5 U/mg, which was 9.5-fold higher compared with PT5 in LB medium, indicating Ptac can be used as an efficient "constitutive" promoter as well as an efficient induced promoter in K. pneumoniae. In different carbon sources medium, a newly constructed endogenous constitutive Pbud proved to be a stable and weak promoter. On the basis of our data, a set of Pbud and Ptac promoters could meet the broad range (about 1,000 orders of magnitude) of gene expression needed for engineered K. pneumoniae in glycerol-based medium.


Assuntos
Vetores Genéticos/genética , Klebsiella pneumoniae/genética , Engenharia Metabólica/métodos , Regiões Promotoras Genéticas/genética , Técnicas de Cultura de Células , Escherichia coli/genética , Genes Reporter/genética , Glucose/farmacologia , Glicerol/farmacologia , Klebsiella pneumoniae/citologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/metabolismo , Óperon Lac/genética
18.
Appl Microbiol Biotechnol ; 100(6): 2775-84, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26695159

RESUMO

To date, few studies have focused on reducing the toxic by-product acetate during 1,3-propanediol production by Klebsiella pneumoniae. In this study, the effects of deleting the poxB, pta, and ackA genes, which are involved in the two main acetate synthesis pathways, on cell growth and 1,3-propanediol production were investigated. Although acetate synthesis via pyruvate oxidase (PoxB, encoded by poxB) generally seems unnecessary and wasteful, PoxB was shown to play an important role in K. pneumoniae. Deletion of poxB severely inhibited cell growth, and the poxB mutant exhibited an anomalously high accumulation of acetate in aerobic cultures and failed to produce an endogenous supply of carbon dioxide (CO2) in anaerobic cultures. It is interesting that both the aerobic and anaerobic growth defects of the poxB mutant were corrected by further deleting pta and ackA, which blocked the other main acetate synthesis pathway. The poxB-pta-ackA mutant excreted less acetate and showed an excellent ability to produce 1,3-propandiol. The final 1,3-propanediol yield and concentration in a 2-L fed-batch fermentation reached 0.66 (mol/mol) and 76.8 g/L, respectively, which were 16 and 15 % greater, respectively, than those of the parent strain.


Assuntos
Proteínas de Bactérias/genética , Deleção de Genes , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Engenharia Metabólica/métodos , Redes e Vias Metabólicas/genética , Propilenoglicóis/metabolismo , Acetatos/metabolismo , Acetatos/toxicidade , Aerobiose , Anaerobiose , Fermentação , Klebsiella pneumoniae/crescimento & desenvolvimento
19.
Biotechnol Lett ; 37(9): 1783-90, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25957564

RESUMO

OBJECTIVE: To improve 1,3-propanediol production in Klebsiella pneumoniae, the effects of puuC expression in lactate- and lactate/2,3-butanediol-deficient strains were assessed. RESULTS: Overexpression of puuC (encoding an aldehyde dehydrogenase) inhibited 1,3-propanediol production and increased 3-hydroxypropionic acid formation in both lactate- and lactate/2,3-butanediol-deficient strains. An improvement in 1,3-propanediol production was only achieved in a lactate-deficient strain via moderate expression of puuC; at the end of the fermentation, 1,3-propanediol productivity increased by 14% compared with the control. Further comparative analysis of the metabolic flux distributions in different strains indicated that 3-hydroxypropionic acid formation could play a considerable role in cell metabolism in K. pneumoniae. CONCLUSION: An improvement in 3-hydroxypropionic acid formation would be beneficial for cell metabolism, which can be accomplished by enhancing 1,3-propanediol productivity in a lactate-deficient strain via moderate expression of puuC.


Assuntos
Aldeído Desidrogenase/metabolismo , Klebsiella pneumoniae/enzimologia , Propilenoglicóis/metabolismo , Aldeído Desidrogenase/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fermentação , Klebsiella pneumoniae/genética , Ácido Láctico/análogos & derivados , Ácido Láctico/metabolismo
20.
Arch Orthop Trauma Surg ; 135(1): 19-28, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25475930

RESUMO

OBJECTIVE: The purpose of this study is to compare the effectiveness and safety of cervical disc arthroplasty with anterior cervical discectomy and fusion for treatment of symptomatic cervical disc disease. Anterior cervical discectomy and fusion (ACDF) is the conventional surgical treatment for symptomatic cervical disc disease. Recently, cervical disc arthroplasty (CDA) has been developed to address some of the shortcomings associated with ACDF by preserving function of the motion segment. Controversy still surrounds regarding whether CDA is better. METHODS: We systematically searched six electronic databases (Medline, Embase, Clinical, Ovid, BIOSIS and Cochrane registry of controlled clinical trials) to identify randomized controlled trials (RCTs) published up to April 2014 in which CDA was compared with ACDF for the treatment of symptomatic cervical disc disease. Effective data were extracted after the assessment of methodological quality of the trials. Then, we performed the meta-analysis. RESULTS: Eighteen relevant RCTs with a total of 4061 patients were included. The results of the meta-analysis indicated that CDA was superior to ACDF regarding better neurological success (P < 0.00001), greater motion preservation at the operated level (P < 0.00001), fewer secondary surgical procedures (P < 0.00001), and fewer rates of adverse events (P < 0.00001) but inferior to ACDF regarding operative times (P < 0.00001). No significant difference was identified between the two groups regarding blood loss (P = 0.87), lengths of hospital stay (P = 0.76), neck pain scores (P = 0.11) and arm pain scores (P = 0.78) reported on a visual analog scale. CONCLUSION: The meta-analysis revealed that CDA demonstrated superiorities in better neurological success, greater motion preservation at the operated level, lower rate of adverse events and fewer secondary surgical procedures compared with ACDF. However, the benefits of blood loss, lengths of hospital stay, neck and arm pain functional recovery are still unable to be proved.


Assuntos
Vértebras Cervicais/cirurgia , Discotomia , Degeneração do Disco Intervertebral/cirurgia , Deslocamento do Disco Intervertebral/cirurgia , Fusão Vertebral , Substituição Total de Disco , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
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