Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 61
Filtrar
1.
Anal Biochem ; 685: 115390, 2024 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-37951454

RESUMEN

To alleviate environmental problems caused by using conventional plastics, bioplastics have garnered significant interest as alternatives to petroleum-based plastics. Despite possessing better degradability traits compared to traditional plastics, the degradation of bioplastics still demands a longer duration than initially anticipated. This necessitates the utilization of degradation strains or enzymes to enhance degradation efficiency, ensuring timely degradation. In this study, a novel screening method to identify bioplastic degraders faster was suggested to circumvent the time-consuming and laborious characteristics of solid-based plate assays. This liquid-based colorimetric method confirmed the extracellular esterase activity with p-nitrophenyl esters. It eliminated the needs to prepare plastic emulsion plates at the initial screening system, shortening the time for the overall screening process and providing more quantitative data. p-nitrophenyl hexanoate (C6) was considered the best substrate among the various p-nitrophenyl esters as substrates. The screening was performed in liquid-based 96-well plates, resulting in the discovery of a novel strain, Bacillus sp. SH09, with a similarity of 97.4% with Bacillus licheniformis. Furthermore, clear zone assays, degradation investigations, scanning electron microscopy, and gel permeation chromatography were conducted to characterize the biodegradation capabilities of the new strain, the liquid-based approach offered a swift and less labor-intensive option during the initial stages.


Asunto(s)
Esterasas , Plásticos , Plásticos/química , Esterasas/química , Ensayos Analíticos de Alto Rendimiento , Colorimetría , Biopolímeros
2.
J Orthop Sci ; 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38423870

RESUMEN

BACKGROUND: The purpose of this study was to compare fracture characteristics and functional outcomes between patients with proximal humerus fractures with and without initial varus displacement. METHODS: A retrospective review of 325 patients with proximal humerus fractures was performed. Patients with initial varus displacement were placed in Varus cohort and were age- and sex-matched 1:1 with a second cohort presenting proximal humerus fractures without varus displacement, referred to as Fracture cohort. Varus fracture displacement was defined when the most proximal aspect of humeral head was below the most proximal aspect of greater tuberosity on initial radiographs, and the head shaft angle was <130°. RESULTS: There were 60 patients in V cohort and 60 patients in F cohort. Statistical analysis revealed that there were significant differences in initial horizontal offset (38.8 vs. 45.9 mm), initial anterior angulation angle (36.5° vs. 16.4°), postoperative head shaft angle (132.2° vs. 141.3°), last head shaft angle (122.2° vs. 138.5°), difference for head shaft angles (10.0° vs. 2.7°), postoperative horizontal offset (43.4 vs. 45.3 mm), last horizontal offset (38.4 vs. 42.8 mm), difference for offsets (4.9 vs. 2.5 mm), complications (15 vs. 7 cases), and revision surgery (7 vs. 1 case) between two cohorts. Overall satisfactory results were achieved in most patients regardless of varus displacement, pain-VAS and Constant scores in V cohort were inferior to the scores in F cohort. The cut-off value of postoperative head shaft angle for good/excellent outcomes was 135.5° using receiver operating characteristic curve analyses. CONCLUSION: Varus displaced proximal humerus fractures were accompanied by decreased horizontal offset and increased anterior angulation angle, and had a course of more varization and horizontal shortening compared with those without initial varus displacement. Patients with varus displaced fractures were associated with worse functional outcomes, and these factors might affect functional outcomes. LEVEL OF EVIDENCE: Prognostic, cohort study, Level III.

3.
Microb Cell Fact ; 22(1): 171, 2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37661274

RESUMEN

Polyhydroxyalkanoate (PHA) is one of the most promising materials for replacing petroleum-based plastics, and it can be produced from various renewable biomass sources. In this study, PHA production was conducted using Halomonas sp. YLGW01 utilizing mixed volatile fatty acids (VFAs) as carbon sources. The ratio and concentration of carbon and nitrogen sources were optimized through mixture analysis and organic nitrogen source screening, respectively. It was found that the highest cell dry weight (CDW) of 3.15 g/L and PHA production of 1.63 g/L were achieved when the ratio of acetate to lactate in the mixed VFAs was 0.45:0.55. Furthermore, supplementation of organic nitrogen sources such as soytone resulted in a ninefold increase in CDW (reaching 2.32 g/L) and a 22-fold increase in PHA production (reaching 1.60 g/L) compared to using inorganic nitrogen sources. Subsequently, DO-stat, VFAs consumption rate stat, and pH-stat fed-batch methods were applied to investigate and evaluate PHA productivity. The results showed that when pH-stat-based VFAs feeding was employed, a CDW of 7 g/L and PHA production of 5.1 g/L were achieved within 68 h, with a PHA content of 73%. Overall, the pH-stat fed-batch strategy proved to be effective in enhancing PHA production by Halomonas sp. YLGW01 utilizing VFAs.


Asunto(s)
Halomonas , Polihidroxialcanoatos , Halomonas/genética , Ácidos Grasos Volátiles , Carbono , Ácido Láctico , Nitrógeno
4.
BMC Musculoskelet Disord ; 24(1): 731, 2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37710239

RESUMEN

BACKGROUND: Segmental fractures often result from high-energy or indirect trauma that causes bending or torsional forces with axial loading. We evaluated surgical outcomes of patients with forearm segmental diaphyseal fractures. METHODS: We retrospectively analyzed data from patients with forearm segmental fractures for which they underwent surgery at the Pusan National University Trauma Center from March 2013 to March 2022. We also analyzed accompanying injuries, injury severity score (ISS), injury mechanism, occurrence of open fracture, surgical technique, and treatment results. RESULTS: Fifteen patients were identified, one with bilateral segmental diaphyseal forearm bone fracture, for a total of 16 cases. Nine of the patients were male. The overall mean age was 50 years, and the mean follow-up period was 16.2 months. Six cases who underwent surgery using plate osteosynthesis achieved bone union without length deformity at final follow-up. Three of seven patients who underwent intramedullary nailing alone underwent reoperation due to nonunion. Six cases achieved bone union at final follow-up, three of which showed length deformity. Three patients underwent surgery using a hybrid method of IM nailing, plates, and mini cables. One patient who underwent surgery with a plate and one patient who underwent surgery with IM nailing alone showed nonunion and were lost to follow-up. CONCLUSION: Plate osteosynthesis is considered the gold standard for treatment of adult forearm diaphyseal segmental fractures. In this study, IM nailing was associated with high rates of non-union and length deformity. However, the combination of IM nailing and a plate-cable system may be an acceptable alternative in segmental diaphyseal forearm fracture, achieving a union rate similar to that provided by plate fixation.


Asunto(s)
Fijación Intramedular de Fracturas , Fracturas Abiertas , Sinostosis , Humanos , Adulto , Masculino , Persona de Mediana Edad , Femenino , Antebrazo , Estudios Retrospectivos , Fijación Interna de Fracturas
5.
Bioprocess Biosyst Eng ; 45(10): 1719-1729, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36121506

RESUMEN

Polyhydroxybutyrate (PHB) is a bio-based, biodegradable and biocompatible plastic that has the potential to replace petroleum-based plastics. Lignocellulosic biomass is a promising feedstock for industrial fermentation to produce bioproducts such as polyhydroxybutyrate (PHB). However, the pretreatment processes of lignocellulosic biomass lead to the generation of toxic byproducts, such as furfural, 5-HMF, vanillin, and acetate, which affect microbial growth and productivity. In this study, to reduce furfural toxicity during PHB production from lignocellulosic hydrolysates, we genetically engineered Cupriavidus necator NCIMB 11599, by inserting the nicotine amide salvage pathway genes pncB and nadE to increase the NAD(P)H pool. We found that the expression of pncB was the most effective in improving tolerance to inhibitors, cell growth, PHB production and sugar consumption rate. In addition, the engineered strain harboring pncB showed higher PHB production using lignocellulosic hydrolysates than the wild-type strain. Therefore, the application of NAD salvage pathway genes improves the tolerance of Cupriavidus necator to lignocellulosic-derived inhibitors and should be used to optimize PHB production.


Asunto(s)
Cupriavidus necator , Petróleo , Amidas/metabolismo , Cupriavidus necator/genética , Cupriavidus necator/metabolismo , Azúcares de la Dieta/metabolismo , Azúcares de la Dieta/farmacología , Furaldehído/farmacología , Inhibidores de Crecimiento/metabolismo , Inhibidores de Crecimiento/farmacología , Hidroxibutiratos/metabolismo , Lignina , NAD/metabolismo , NAD/farmacología , Nicotina/metabolismo , Nicotina/farmacología , Nitrobencenos , Petróleo/metabolismo , Plásticos
6.
J Shoulder Elbow Surg ; 31(11): 2233-2241, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35613696

RESUMEN

BACKGROUND: Although partial rotator cuff repair has shown good outcomes, differences in clinical outcomes remain concerns. This study was performed to determine whether patients with humeral head coverage would show better functional outcomes than patients without humeral head coverage and to identify the factors for humeral head coverage after arthroscopic partial repair of massive tears. METHODS: We performed a retrospective study of 63 patients with massive rotator cuff tears who underwent arthroscopic partial repair between 2012 and 2018. Two to four margin convergences were first performed; then, the Mason-Allen technique was performed. The patients were divided into 2 groups: those with humeral head coverage (38 cases) and those without humeral head coverage (25 cases). The following factors were evaluated: age; sex; hypertension; diabetes; osteoporosis; preoperative and postoperative pseudoparalysis, visual analog scale (VAS) pain score, Constant score, acromiohumeral distance, and subacromial bony spur; and subscapularis tear and repair. Muscle atrophy and fatty degeneration were evaluated by magnetic resonance imaging preoperatively, and the integrity of the repaired cuff was evaluated by ultrasonography at a minimum of 2 years after surgery. RESULTS: Compared with preoperative values, significant improvements in VAS pain scores (from 6.27 to 2.32 in patients with humeral head coverage and from 7.00 to 2.81 in those without humeral head coverage) and Constant scores (from 51.35 to 75.95 and from 44.62 to 69.81, respectively) were observed in both groups (P < .001). Statistical analysis revealed that postoperative VAS pain scores (2.32 vs. 2.81) and Constant scores (75.95 vs. 69.81) in patients with humeral head coverage were superior to those in patients without humeral head coverage (P = .044 and P = .003, respectively). The integrity of the repaired cuff was evaluated by ultrasonography, and partial tears were found in 4 of 37 patients with humeral head coverage and 2 of 26 patients without humeral head coverage (P = .816). Univariable logistic regression analysis revealed that age (P < .001), comorbidity (P = .005), symptom duration (P = .023), preoperative shoulder mobility (P < .001), maintained acromiohumeral distance (P = .006), subscapularis tear (P = .026), and less preoperative supraspinatus and infraspinatus muscle atrophy (P = .001 and P = .010, respectively) had significant correlations with humeral head coverage. CONCLUSIONS: Overall satisfactory results were achieved in most patients regardless of high retear rates, but patients with partial repair covering the humeral head were associated with better outcomes than patients without humeral head coverage. Multivariable regression analysis revealed that age (<70 years, P = .003), capability of shoulder mobility (P = .005), maintenance of the acromiohumeral space (>7 mm, P = .016), and less atrophy of the rotator cuff muscles (P = .021) were favorable factors to achieve humeral head coverage during surgical partial repair of massive rotator cuff tears.


Asunto(s)
Laceraciones , Lesiones del Manguito de los Rotadores , Humanos , Anciano , Lesiones del Manguito de los Rotadores/cirugía , Lesiones del Manguito de los Rotadores/patología , Estudios Retrospectivos , Cabeza Humeral/diagnóstico por imagen , Cabeza Humeral/cirugía , Cabeza Humeral/patología , Artroscopía/métodos , Resultado del Tratamiento , Rotura/cirugía , Laceraciones/cirugía , Imagen por Resonancia Magnética , Atrofia Muscular/patología , Dolor
7.
J Orthop Sci ; 2022 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-36411226

RESUMEN

BACKGROUND: Compared with posterior interbody fusion techniques, oblique lateral interbody fusion (OLIF) offers a larger fusion bed with greater intervertebral space access, use of larger cages, more sufficient discectomy, and better end-plate preparation. However, the fusion rate of OLIF is similar to that of other interbody fusions. This study aimed to examine the factors associated with nonunion in OLIF. METHODS: This study examined 201 disc levels from 124 consecutive patients who underwent OLIF for lumbar degenerative diseases with 1-year regular follow-up. Demographic and surgical factors were reviewed from the medical records. Radiological factors measured were sagittal parameters, intervertebral disc angle (DA) before surgery and at the final follow-up, presence of vertebral end-plate lesions, and cage subsidence. Multivariable logistic regression analysis was performed to identify the factors associated with nonunion. RESULTS: Among the 201 discs, 185 (92.0%) achieved union at 1-year followed up. Smoking, surgery at the L5-S1 level, not performing laminectomy, and a large intervertebral DA were factors associated with nonunion in OLIF (all P < 0.05). Multivariable logistic regression analysis showed two independent variables (surgery at L5-S1 level and not performing laminectomy) as risk factors for nonunion in OLIF. CONCLUSIONS: Not performing laminectomy and surgery at the L5-S1 level were risk factors for nonunion in OLIF. To reduce the nonunion rate, surgeons should consider additional stabilization strategies for the L5-S1 OLIF and perform laminectomy.

8.
Biotechnol Bioeng ; 115(8): 1971-1978, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29663332

RESUMEN

Acetic acid is an abundant material that can be used as a carbon source by microorganisms. Despite its abundance, its toxicity and low energy content make it hard to utilize as a sole carbon source for biochemical production. To increase acetate utilization and isobutanol production with engineered Escherichia coli, the feasibility of utilizing acetate and metabolic engineering was investigated. The expression of acs, pckA, and maeB increased isobutanol production by up to 26%, and the addition of TCA cycle intermediates indicated that the intermediates can enhance isobutanol production. For isobutanol production from acetate, acetate uptake rates and the NADPH pool were not limiting factors compared to glucose as a carbon source. This work represents the first approach to produce isobutanol from acetate with pyruvate flux optimization to extend the applicability of acetate. This technique suggests a strategy for biochemical production utilizing acetate as the sole carbon source.


Asunto(s)
Acetato CoA Ligasa/biosíntesis , Acetato CoA Ligasa/metabolismo , Acetatos/metabolismo , Butanoles/metabolismo , Escherichia coli/metabolismo , Expresión Génica , Ingeniería Metabólica/métodos , Acetato CoA Ligasa/genética , Escherichia coli/genética
9.
Bioprocess Biosyst Eng ; 41(8): 1195-1204, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29737409

RESUMEN

n-Butanol is considered as the next-generation biofuel, because its physiochemical properties are very similar to fossil fuels and it could be produced by Clostridia under anaerobic culture. Due to the difficulties of strict anaerobic culture, a host which can be used with facultative environment was being searched for n-butanol production. As an alternative, Shewanella oneidensis MR-1, which is known as facultative bacteria, was selected as a host and studied. A plasmid containing adhE2 encoding alcohol dehydrogenase, various CoA transferases (ctfAB, atoAD, pct, and ACT), and acs encoding acetyl-CoA synthetase were introduced and examined to S. oneidensis MR-1 to produce n-butanol. As a result, ctfAB, acs, and adhE2 overexpression in S. oneidensis-pJM102 showed the highest n-butanol production in the presence of 2% of N-acetylglucosamine (NAG), 0.3% of butyrate, and 0.1 mM of IPTG for 96 h under microaerobic condition. When more NAG and butyrate were fed, n-butanol production was enhanced, producing up to 160 mg/L of n-butanol. When metal ions or extra electrons were added to S. oneidensis-pJM102 for n-butanol production, metal ion as electron acceptor or supply of extra electron showed no significant effect on n-butanol production. Overall, we made a newly engineered S. oneidensis that could utilize NAG and butyrate to produce n-butanol. It could be used in further microaerobic condition and electricity supply studies.


Asunto(s)
1-Butanol/metabolismo , Proteínas Bacterianas , Butiratos/metabolismo , Microorganismos Modificados Genéticamente , Plásmidos , Shewanella , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/genética , Clostridium/genética , Microorganismos Modificados Genéticamente/crecimiento & desarrollo , Microorganismos Modificados Genéticamente/metabolismo , Plásmidos/genética , Plásmidos/metabolismo , Shewanella/genética , Shewanella/crecimiento & desarrollo
10.
Bioprocess Biosyst Eng ; 41(2): 229-235, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29124334

RESUMEN

Polyhydroxyalkonate (PHA) is a type of polymer that has the potential to replace petro-based plastics. To make PHA production more economically feasible, there is a need to find a new carbon source and engineer microbes to produce a commercially valuable polymer. Coffee waste is an inexpensive raw material that contains fatty acids. It can act as a sustainable carbon source and seems quite promising with PHA production in Ralstonia eutropha, which is a well-known microbe for PHA accumulation, and has the potential to utilize fatty acids. In this study, to make poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)), which has superior properties in terms of biodegradability, biocompatibility, and mechanical strength, engineered strain Ralstonia eutropha Re2133 overexpressing (R)-specific enoyl coenzyme-A hydratase (phaJ) and PHA synthetase (phaC2) with deletion of acetoacetyl Co-A reductases (phaB1, phaB2, and phaB3) was used to produce PHA from coffee waste oil. At a coffee oil concentration of 1.5%, and C/N ratio of 20, the R. eutropha Re2133 fermentation process results in 69% w/w of DCW PHA accumulation and consists of HB (78 mol%) and HHx (22 mol%). This shows the feasibility of using coffee waste oil for P(HB-co-HHx) production, as it is a low-cost fatty acid enriched waste material.


Asunto(s)
Ácido 3-Hidroxibutírico/biosíntesis , Proteínas Bacterianas , Café/química , Cupriavidus necator , Ingeniería Metabólica , Aceites de Plantas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Caproatos , Cupriavidus necator/genética , Cupriavidus necator/metabolismo
11.
Bioprocess Biosyst Eng ; 40(5): 781-789, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28204983

RESUMEN

Polyhydroxyalkanoate (PHA) is a family of biodegradable polymers, and incorporation of different monomers can alter its physical properties. To produce the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) containing a high level of 3-hydroxyvalerate (3HV) by altering acetyl-CoA pool levels, we overexpressed an acetyl-CoA acetyltransferase (atoAD) in an engineered E. coli strain, YH090, carrying PHA synthetic genes bktB, phaB, and phaC. It was found that, with introduction of atoAD and with propionate as a co-substrate, 3HV fraction in PHA was increased up to 7.3-fold higher than a strain without atoAD expressed in trans (67.9 mol%). By the analysis of CoA pool concentrations in vivo and in vitro using HPLC and LC-MS, overexpression of AtoAD was shown to decrease the amount of acetyl-CoA and increase the propionyl-CoA/acetyl-CoA ratio, ultimately resulting in an increased 3HV fraction in PHA. Finally, synthesis of P(3HB-co-3HV) containing 57.9 mol% of 3HV was achieved by fed-batch fermentation of YJ101 with propionate.


Asunto(s)
Acetil-CoA C-Acetiltransferasa/biosíntesis , Proteínas de Escherichia coli/biosíntesis , Escherichia coli/metabolismo , Ácidos Pentanoicos/metabolismo , Poliésteres/metabolismo , Acetil-CoA C-Acetiltransferasa/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética
12.
J Ind Microbiol Biotechnol ; 43(1): 37-44, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26660478

RESUMEN

Furfural is a toxic by-product formulated from pretreatment processes of lignocellulosic biomass. In order to utilize the lignocellulosic biomass on isobutanol production, inhibitory effect of the furfural on isobutanol production was investigated and combinatorial application of two oxidoreductases, FucO and YqhD, was suggested as an alternative strategy. Furfural decreased cell growth and isobutanol production when only YqhD or FucO was employed as an isobutyraldehyde oxidoreductase. However, combinatorial overexpression of FucO and YqhD could overcome the inhibitory effect of furfural giving higher isobutanol production by 110% compared with overexpression of YqhD. The combinatorial oxidoreductases increased furfural detoxification rate 2.1-fold and also accelerated glucose consumption 1.4-fold. When it compares to another known system increasing furfural tolerance, membrane-bound transhydrogenase (pntAB), the combinatorial aldehyde oxidoreductases were better on cell growth and production. Thus, to control oxidoreductases is important to produce isobutanol using furfural-containing biomass and the combinatorial overexpression of FucO and YqhD can be an alternative strategy.


Asunto(s)
Aldehído Oxidorreductasas/metabolismo , Butanoles/metabolismo , Escherichia coli/metabolismo , Furaldehído/metabolismo , Aldehídos/metabolismo , Biomasa , División Celular/efectos de los fármacos , Escherichia coli/citología , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Furaldehído/farmacología , Glucosa/metabolismo , NADP Transhidrogenasas/metabolismo
13.
Bioprocess Biosyst Eng ; 38(11): 2147-54, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26280214

RESUMEN

Shewanella oneidensis MR-1 is one of the most well-known metal-reducing bacteria and it has been extensively studied for microbial fuel cell and bioremediation aspects. In this study, we have examined S. oneidensis MR-1 as an isobutanol-producing host by assessing three key factors such as isobutanol synthetic genes, carbon sources, and electron supply systems. Heterologous Ehrlich pathway genes, kivD encoding ketoisovalerate decarboxylase and adh encoding alcohol dehydrogenase, were constructed in S. oneidensis MR-1. Among the composition of carbon sources examined, 2% of N-acetylglucosamine, 1.5% of pyruvate and 2% of lactate were found to be the most optimal nutrients and resulted in 10.3 mg/L of isobutanol production with 48 h of microaerobic incubation. Finally, the effects of metal ions (electron acceptor) and direct electron transfer systems on isobutanol production were investigated, and Fe(2+) ions increased the isobutanol production up to 35%. Interestingly, deletion of mtrA and mtrB, genes responsible for membrane transport systems, did not have significant impact on isobutanol production. Finally, we applied engineered S. oneidensis to a bioelectrical reactor system to investigate the effect of a direct electron supply system on isobutanol production, and it resulted in an increased growth and isobutanol production (up to 19.3 mg/L). This report showed the feasibility of S. oneidensis MR-1 as a genetic host to produce valuable biochemicals and combine an electron-supplying system with biotechnological applications.


Asunto(s)
Butanoles/metabolismo , Ingeniería Metabólica/métodos , Shewanella/metabolismo , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/genética , Shewanella/genética
14.
Bioprocess Biosyst Eng ; 38(8): 1479-84, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25820819

RESUMEN

Every year, the amount of chemosynthetic plastic accumulating in the environment is increasing, and significant time is required for decomposition. Bio-based, biodegradable plastic is a promising alternative, but its production is not yet a cost effective process. Decreasing the production cost of polyhydroxyalkanoate by utilizing renewable carbon sources for biosynthesis is an important aspect of commercializing this biodegradable polymer. An Escherichia coli strain that expresses a functional amylase and accumulate polyhydroxybutyrate (PHB), was constructed using different plasmids containing the amylase gene of Panibacillus sp. and PHB synthesis genes from Ralstonia eutropha. This engineered strain can utilize starch as the sole carbon source. The maximum PHB production (1.24 g/L) was obtained with 2% (w/v) starch in M9 media containing 0.15% (w/v) yeast extract and 10 mM glycine betaine. The engineered E. coli SKB99 strain can accumulate intracellular PHB up to 57.4% of cell dry mass.


Asunto(s)
Escherichia coli/metabolismo , Hidroxibutiratos/metabolismo , Ingeniería Metabólica , Poliésteres/metabolismo , Almidón/metabolismo , Amilasas/biosíntesis , Cupriavidus necator/enzimología , Cupriavidus necator/genética , Escherichia coli/genética , Proteínas Recombinantes/biosíntesis
15.
Appl Microbiol Biotechnol ; 98(12): 5461-9, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24615385

RESUMEN

Polyhydroxyalkanoates (PHAs), a promising family of bio-based polymers, are considered to be alternatives to traditional petroleum-based plastics. Copolymers like poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) have been shown to exhibit favorable physical and mechanical properties, due to decreased crystallinity resulting from the presence of medium-chain-length 3-hydroxyhexanoate (3HHx) monomers. In this study, we produced P(HB-co-HHx) using engineered Ralstonia eutropha strains containing deletions of the acetoacetyl-CoA reductase (phaB) genes and replacing the native PHA synthase with phaC2 from Rhodococcus aetherivorans I24 and by using butyrate, a short-chain organic acid, as the carbon source. Although the wild-type R. eutropha did not produce P(HB-co-HHx) when grown on mixed acids or on butyrate as the sole carbon source, we are able to produce polymer containing up to 40 wt% 3HHx monomer with the aforementioned engineered R. eutropha strains using various concentrations of just butyrate as the sole carbon source. This is the first report for the production of P(HB-co-HHx) copolymer in R. eutropha using butyrate.


Asunto(s)
Ácido 3-Hidroxibutírico/biosíntesis , Butiratos/metabolismo , Cupriavidus necator/genética , Cupriavidus necator/metabolismo , Aciltransferasas/genética , Aciltransferasas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Caproatos , Ingeniería Metabólica
16.
Int J Biol Macromol ; 254(Pt 1): 127475, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37863147

RESUMEN

Polyhydroxybutyrate (PHB) is a well-known biodegradable bioplastic synthesized by microorganisms and can be produced from volatile fatty acids (VFAs). Among VFAs acetate can be utilized by Halomonas sp. YLGW01 for growth and PHB production. In this study, Halomonas sp. JJY01 was developed through introducing acetyl-CoA acetyltransferase (atoAD) with LacIq-Ptrc promoter into Halomonas sp. YLGW01. The effect of expression of atoAD on acetate was investigated by comparison with acetate consumption and PHB production. Shake-flask study showed that Halomonas sp. JJY01 increased acetate consumption rate, PHB yield and PHB production (0.27 g/L/h, 0.075 g/g, 0.72 g/L) compared to the wild type strain (0.17 g/L/h, 0.016 g/g, 0.11 g/L). In 10 L fermenter scale fed-batch fermentation, the growth of Halomonas sp. JJY01 resulted in higher acetate consumption rate, PHB yield and PHB titer (0.55 g/L/h, 0.091 g/g, 4.6 g/L) than wild type strain (0.35 g/L/h, 0.067 h/h, 2.9 g/L). These findings demonstrate enhanced acetate utilization and PHB production through the introduction of atoAD in Halomonas strains.


Asunto(s)
Halomonas , Hidroxibutiratos , Hidroxibutiratos/metabolismo , Halomonas/genética , Halomonas/metabolismo , Acetil-CoA C-Acetiltransferasa/metabolismo , Polihidroxibutiratos , Acetatos/metabolismo , Poliésteres/metabolismo
17.
Bioorg Med Chem Lett ; 23(12): 3614-9, 2013 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-23659856

RESUMEN

Although phosphorylation of chloramphenicol has been shown to occur in the chloramphenicol producer, Streptomyces venezuelae, there are no reports on the existence of chloramphenicol phosphorylase in other Streptomyces species. In the present study, we report the modification of chloramphenicol by a recombinant protein, designated as Yhr2 (encoded by SAV_877), from Streptomyces avermitilis MA4680. Recombinant Yhr2 was expressed in Escherichia coli BL21 (DE3) and the cells expressing this recombinant protein were shown to phosphorylate chloramphenicol to a 3'-O-phosphoryl ester derivative, resulting in an inactivated form of the antibiotic. Expression of yhr2 conferred chloramphenicol resistance to E. coli cells up to 25 µg/mL and in an in vitro reaction, adenosine triphosphate (ATP), guanosine triphosphate (GTP), adenosine diphosphate (ADP) and guanosine diphosphate (GDP) were shown to be the phosphate donors for phosphorylation of chloramphenicol. This study highlights that antibiotic resistance conferring genes could be easily expressed and functionalized in other organisms that do not produce the respective antibiotic.


Asunto(s)
Cloranfenicol/metabolismo , Fosfotransferasas/metabolismo , Streptomyces/metabolismo , Secuencia de Aminoácidos , Animales , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Datos de Secuencia Molecular , Fosforilación , Fosfotransferasas/genética , Proteínas Recombinantes/metabolismo , Streptomyces/enzimología , Streptomyces/genética
18.
Appl Microbiol Biotechnol ; 97(15): 6823-33, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23525887

RESUMEN

Several reports state that three architectural units, including integration host factor, leucyl aminopeptidase (PepA), and purine regulator, are involved in transcriptional process with RNA polymerase in Escherichia coli. Similarly, Streptomyces species possess the same structural units. We previously identified a protein, Streptomyces integration host factor (sIHF), involved in antibiotic production and sporulation. Subsequently, the function of PepA (SCO2179) was examined in detail. PepA is highly conserved among various Streptomyces spp., but it has not yet been characterized in Streptomyces coelicolor. While it is annotated as a putative leucyl aminopeptidase because it contains a peptidase M17 superfamily domain, this protein did not exhibit leucyl aminopeptidase activity. SCO2179 deletion mutant showed increased actinorhodin production and sporulation, as well as more distinct physiological differences, particularly when cultured on N-acetylglucosamine (GlcNAc) minimal media. The results of two-dimensional gel analysis and reverse transcription PCR showed that the SCO2179 deletion increased protein and mRNA levels of ftsZ, ssgA, and actinorhodin (ACT)-related genes such as actII-ORF4, resulting in increased actinorhodin production and spore formation in minimal media containing GlcNAc.


Asunto(s)
Leucil Aminopeptidasa/metabolismo , Esporas Bacterianas , Streptomyces coelicolor/enzimología , Secuencia de Aminoácidos , Antraquinonas/metabolismo , Secuencia de Bases , Cartilla de ADN , Leucil Aminopeptidasa/química , Leucil Aminopeptidasa/genética , Microscopía Electrónica de Rastreo , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , ARN Mensajero/genética , Homología de Secuencia de Aminoácido , Streptomyces coelicolor/fisiología
19.
Indian J Orthop ; 57(9): 1415-1422, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37609026

RESUMEN

Background: Percutaneous pedicle screw fixation (PPSF) without fusion has been recently recommended in the treatment of thoracolumbar fracture to reduce the adverse effects associated with the conventional open approaches and to restore range of motion. However, those studies report on the thoracolumbar junction, and there is no report on lower lumbar fracture. Purpose: To assess effectiveness of PPSF without fusion for treating lower lumbar burst (A3 and A4) fractures. Methods: A retrospective analysis was made to evaluate consecutive 50 patients with AO type A3 and A4 thoracolumbar fracture underwent PPSF. Patients were divided into a thoracolumbar junction (TLJ) group (T11-L2) and lower lumbar (LL) group (L3-5). The following items were measured and compared between the two groups. Vertebral height and consolidation, retropulsed fragment, sagittal curve and fixation failure were assessed with certain interval regularly. Results: The average height at pre- and post-reduction were 56.2% (36.2-74.3), 95.3% (84.2-98.3) in TLJ group and 65.7% (45.7-86.2), 91% (73.1-100) in LL group. The average canal area occupancy rate at pre- and post-reduction were 46.1% (37.4%-67.5%), 38.1% (31.3%-40.8%) in TLJ group and 40.4% (15.0-65.7), 19.3% (9.4-26.6) in LL group. Consolidation was completed within 12 months after surgery in both groups. There was no significant difference between two groups in clinical and radiographic parameters except cobb angle loss. Conclusion: Patients with lower lumbar fracture can be effectively managed with PPSF without fusion. PPSF following the implant removal can restore the movement of the lower lumbar spine, which is essential for daily life.

20.
J Hand Surg Asian Pac Vol ; 28(3): 415-420, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37173139

RESUMEN

Surgical principles in sarcoma are a wide resection, including surrounding tissues and maximisation of the function of the affected limb. Rotator cuff muscles are biomechanically important structures acting as a force couple in movement of the shoulder joint. Thus, conjoined tendons are essential for motion capability in absence of the supraspinatus muscle. This article reports a case of a large undifferentiated pleomorphic sarcoma (UPS) at the suprascapular fossa in a 78-year-old man. After diagnosis of sarcoma, he underwent wide, en-bloc excision preserving conjoined tendons of rotator cuff muscles and low-dose radiation therapy for surveillance of local recurrence. All dissection was performed to avoid contaminating the tumour and involved the whole supraspinatus except the conjoined tendons. We report a case of UPS at the suprascapular fossa, which showed a good result after a wide resection preserving conjoined tendons of rotator cuff muscles. Level of Evidence: Level V (Therapeutic).


Asunto(s)
Sarcoma , Neoplasias de los Tejidos Blandos , Masculino , Humanos , Anciano , Manguito de los Rotadores/diagnóstico por imagen , Manguito de los Rotadores/cirugía , Sarcoma/cirugía , Disección , Movimiento (Física) , Movimiento , Neoplasias de los Tejidos Blandos/diagnóstico por imagen , Neoplasias de los Tejidos Blandos/cirugía
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA