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1.
Bioresour Technol ; 247: 395-401, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28961445

RESUMO

Oleaginous yeast Cryptococcus curvatus MUCL 29819, an acid-tolerant lipid producer, was tested to spill lipids extracellularly using different concentrations of acetic acid as carbon source. Extracellular lipids were released when the yeast was cultured with acetic acid exceeding 20g/L. The highest production of lipid (5.01g/L) was obtained when the yeast was cultured with 40g/L acetic acid. When the yeast was cultivated with moderate concentration (20g/L) of acetic acid, lipid production was further increased by 49.6% through preculture with 40g/L acetic acid as stimulant. When applying high concentration (40g/L) of acetic acid as carbon source in sequencing batch cultivation, extracellular lipids accounted up to 50.5% in the last cycle and the extracellular lipids reached 5.43g/L through the whole process. This study provides an effective strategy to enhance extracellular lipid production and facilitate the recovery of microbial lipids.


Assuntos
Ácido Acético , Lipídeos , Técnicas de Cultura Celular por Lotes , Biomassa , Carbono , Cryptococcus
2.
Bioresour Technol ; 241: 645-651, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28609752

RESUMO

The oleaginous yeast Cryptococcus curvatus ATCC 20509 can use 5-40g/L of acetic, propionic, or butyric acid as sole carbon source to produce lipids. High concentrations (30g/L) of mixed volatile fatty acids (VFAs) were used to cultivate C. curvatus to explore the effects of different ratios of mixed VFAs on lipid production and composition. When mixed VFAs (VFA ratio was 15:5:10) were used as carbon sources, the highest cell mass and lipid concentration were 8.68g/L and 4.93g/L, respectively, which were significantly higher than those when 30g/L of acetic acid was used as sole carbon source. The highest content and yield of odd-numbered fatty acids were 45.1% (VFA ratio was 0:15:15) and 1.62g/L (VFA ratio was 5:15:10), respectively. These results indicate that adjusting the composition ratios of mixed VFAs effectively improves microbial lipid synthesis and the yield of odd-numbered fatty acids.


Assuntos
Cryptococcus , Ácidos Graxos Voláteis , Ácidos Graxos , Lipídeos , Leveduras
3.
Bioresour Technol ; 239: 394-401, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28535491

RESUMO

The lower utilization ratios of high-content VFAs resulted in less lipid yield by the oleaginous yeast Cryptococcus curvatus ATCC 20509. In this work, increasing the inoculation concentration to OD600=5.1 improved the acetic acid utilization ratio (99.8%) and lipids production (4.63g/L) in mediums with 30g/L of acetic acid. For the higher acetic acid concentration (40g/L), increasing the nitrogen to carbon ratio (0.033) and raising the initial pH (pH=8) was superior over improvement in the inoculate, with the lipid production increased from 1.08g/L to 6.49g/L. Subsequently, mixed VFAs at concentrations of 30g/L and 40g/L were used as the carbon source to simulate waste-derived VFAs. High lipid production (4.82 and 7.45g/L, respectively) was correspondingly achieved with similar high lipid yield (0.187g/g). This study provides an effective strategy to enhance the bioconversion of high-content VFAs into microbial lipids.


Assuntos
Cryptococcus , Ácidos Graxos Voláteis , Lipídeos , Carbono , Ácidos Graxos , Nitrogênio
4.
Chem Rev ; 117(9): 6160-6224, 2017 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-28426202

RESUMO

Hypoxia development in tumor is closely associated with its increased aggressiveness and strong resistance to therapy, leading to the poor prognosis in several cancer types. Clinically, invasive oxygen microelectrode and high dosage radiotherapy are often utilized to accurately detect and effectively fight hypoxia. Recently, however, there has been a surge of interdisciplinary research aiming at developing functional molecules and nanomaterials that can be used to noninvasively image and efficiently treat hypoxic tumors. In this review, we will provide an overview of the reports published to date on the imaging and therapy of hypoxic tumors. First, we will present the design concepts and engineering of various hypoxia-responsive probes that can be applied to image hypoxia noninvasively, in an order of fluorescent imaging, positron emission tomography, magnetic resonance imaging, and photoacoustic imaging. Then, we will summarize the up-to-date functional nanomaterials which can be used for the effective treatments of tumor hypoxia. The well-established chemical functions of these elaborately designed nanostructures will enable clinicians to adopt specific treatment concepts by overcoming or even utilizing hypoxia. Finally, challenges and future perspectives facing the researchers in the field will be discussed.


Assuntos
Técnicas de Química Sintética/métodos , Desenho de Drogas , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Imagem Molecular/métodos , Hipóxia Tumoral/efeitos dos fármacos , Animais , Corantes Fluorescentes/química , Corantes Fluorescentes/uso terapêutico , Humanos , Técnicas Fotoacústicas
5.
World J Gastroenterol ; 23(12): 2175-2184, 2017 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-28405145

RESUMO

AIM: To examine the effects of Acanthopanax senticosus polysaccharides (ASPS) on intestinal tight junction (TJ) disruption and nuclear factor-kappa B (NF-κB)/myosin light chain kinase (MLCK) activation in endotoxemia. METHODS: BALB/C mice (6-8-weeks-old) received continuous intragastric gavage of ASPS for 7 d before injection of lipopolysaccharide (LPS), or received ASPS once after LPS injection. Blood and intestinal mucosal samples were collected 6 h after LPS challenge. Clinical symptoms, histological injury, intestinal permeability, TJ ultrastructure, and TJ protein expression were determined. RESULTS: Compared with mice in the LPS group, pretreatment with ASPS improved clinical and histological scores by 390.9% (P < 0.05) and 57.89% (P < 0.05), respectively, and gut permeability change in endotoxemic mice was shown by a 61.93% reduction in reduced leakage of fluorescein isothiocyanate-dextran 6 h after LPS injection (P < 0.05). ASPS pretreatment also prevented LPS-induced TJ ultrastructure breakdown supported by increased electron dense materials between adjoining cells, sustained redistribution and expression of occludin (0.597 ± 0.027 vs 0.103 ± 0.009, P < 0.05) and zonula occludens-1 (0.507 ± 0.032 vs 0.125 ± 0.019, P < 0.05), and suppressed activation of the NF-κB/MLCK pathway indicated by reduced expression of NF-κB, phospho-inhibitor kappa B-alpha, MLCK and phospho-myosin light-chain-2 by 16.06% (P < 0.05), 54.31% (P < 0.05), 66.10% (P < 0.05) and 64.82% (P < 0.05), respectively. CONCLUSION: ASPS pretreatment may be associated with inhibition of the NF-κB/MLCK pathway and concomitant amelioration of LPS-induced TJ dysfunction of intestinal epithelium in endotoxemia.


Assuntos
Eleutherococcus/química , Endotoxemia/tratamento farmacológico , Quinase de Cadeia Leve de Miosina/metabolismo , NF-kappa B/metabolismo , Polissacarídeos/química , Junções Íntimas/química , Animais , Permeabilidade da Membrana Celular , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Mucosa Intestinal/metabolismo , Intestinos/patologia , Lipopolissacarídeos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Permeabilidade , Transdução de Sinais
6.
Bioresour Technol ; 222: 75-81, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27710909

RESUMO

Four mixed volatile fatty acids (VFAs) were used as sole carbon source to culture oleaginous yeast Cryptococcus curvatus by sequencing batch culture strategy. The highest lipid content (42.7%) and concentration (1.77g/L) were achieved when the ratio of VFAs (acetic, propionic, and butyric acids) was 6:3:1. The oleaginous yeast favored to use VFAs for lipid biosynthesis rather than cell proliferation. With regard to the utilization ratio of VFAs, acetic acid reached over 99%, whereas propionic acid was barely 35%. The produced lipids contained nearly 45% of monounsaturated fatty acids, which can be the ideal raw materials for biodiesel production. Additionally, the produced odd-numbered fatty acid content reached 23.6% when the propionate acid content of VFAs was 50%. Further analysis showed that increasing the ratio of acetic acid was most beneficial to cell mass and lipid production, whereas propionic acid and butyric acid were more conducive to lipid and cell mass synthesis, respectively.


Assuntos
Técnicas de Cultura Celular por Lotes/métodos , Cryptococcus/metabolismo , Ácidos Graxos Voláteis/metabolismo , Lipídeos/biossíntese , Biomassa , Ésteres/metabolismo , Análise de Componente Principal
7.
Sci Rep ; 6: 31405, 2016 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-27510858

RESUMO

N, N-diethyl-m-toluamide (DEET) is one of the important emerging contaminants that are being increasingly detected in reclaimed water as well as in drinking water sources. However, DEET is refractory to conventional biological treatment and pure ozone which is absent of hydroxyl radical. Current researches on the efficient removal of DEET are still quite limited. This study utilizes a novel method, namely ozone/graphene oxide (O3/GO), to investigate the effects on DEET removal in aqueous systems, especially in reclaimed water. The results indicate that the DEET degradation rate was significantly accelerated through the combined effect of GO and ozonation which can yield abundant hydroxyl radical, compared to pure ozone condition. According to hydroxyl radical scavenging experiments, hydroxyl radical was found to play a dominant role in synergistic removal of DEET. These findings can offer sound suggestions for future research on the removal of emerging organic contaminants. The information could also be beneficial to reclaimed water safety and sustainable management.

8.
Bioresour Technol ; 211: 548-55, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27038264

RESUMO

Pure volatile fatty acid (VFA) solution derived from waste activated sludge (WAS) was used to produce microbial lipids as culture medium in this study, which aimed to realize the resource recovery of WAS and provide low-cost feedstock for biodiesel production simultaneously. Cryptococcus curvatus was selected among three oleaginous yeast to produce lipids with VFAs derived from WAS. In batch cultivation, lipid contents increased from 10.2% to 16.8% when carbon to nitrogen ratio increased from about 3.5 to 165 after removal of ammonia nitrogen by struvite precipitation. The lipid content further increased to 39.6% and the biomass increased from 1.56g/L to 4.53g/L after cultivation for five cycles using sequencing batch culture (SBC) strategy. The lipids produced from WAS-derived VFA solution contained nearly 50% of monounsaturated fatty acids, including palmitic acid, heptadecanoic acid, ginkgolic acid, stearic acid, oleic acid, and linoleic acid, which showed the adequacy of biodiesel production.


Assuntos
Biocombustíveis , Ácidos Graxos Voláteis/metabolismo , Lipídeos/biossíntese , Esgotos/química , Técnicas de Cultura Celular por Lotes , Biomassa , Carbono/análise , Carbono/metabolismo , Cryptococcus , Meios de Cultura , Lipídeos/química , Nitrogênio/análise , Nitrogênio/metabolismo , Esgotos/microbiologia
9.
Bioresour Technol ; 206: 141-149, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26851898

RESUMO

Rhodosporidium toruloides AS 2.1389 was tested using different concentrations of acetic acid as a low-cost carbon source for the production of microbial lipids, which are good raw materials for biodiesel production. It grew and had higher lipid contents in media containing 4-20 g/L acetic acid as the sole carbon source, compared with that in glucose-containing media under the same culture conditions. At acetic acid concentrations as high as 20 g/L and the optimal carbon-to-nitrogen ratio (C/N) of 200 in a batch culture, the highest biomass production was 4.35 g/L, with a lipid content of 48.2%. At acetic acid concentrations as low as 4 g/L, a sequencing batch culture (SBC) with a C/N of 100 increased biomass production to 4.21 g/L, with a lipid content of 38.6%. These results provide usable culture strategies for lipid production by R. toruloides AS 2.1389 when using diverse waste-derived volatile fatty acids.


Assuntos
Ácido Acético/metabolismo , Basidiomycota/metabolismo , Técnicas de Cultura Celular por Lotes/métodos , Lipídeos/biossíntese , Biocombustíveis , Biomassa , Carbono/metabolismo , Ácidos Graxos Voláteis/metabolismo , Microbiologia Industrial/métodos , Nitrogênio/metabolismo
10.
Acc Chem Res ; 48(7): 1797-805, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-26057000

RESUMO

Next generation theranostic devices will rely on the smart integration of different functional moieties into one system. These individual chemical elements will have a variety of desired chemical and physical properties and will need to behave in a multifunctional manner. Researchers have used upconversion nanoparticles (UCNPs) as a basis for superior imaging probes to locate cancerous lesions. The features of these nanoparticles, such as large anti-Stokes shifts, sharp emission bands, long-lived luminescence, and high resistance to photobleaching, have produced versatile probes. One way to improve these probes is to add a layer of dense or mesoporous silica to the outer surface of UCNPs (UCNP@SiO2). These modified UCNPs are chemically stable and much less cytotoxic than the original UCNPs. In addition, their surface can be easily modified to introduce various functional groups (e.g., -NH2, -COOH, -SH) via silanization, which facilitates conjugations with various biological molecules for multimodal imaging or synergetic therapeutics. This versatility makes UCNP@SiO2 particles excellent platforms for the construction of efficient theranostics. In this Account, we provide a comprehensive summary of recent progress in the development of UCNP@SiO2 nanocomposites for theranostics in the hope of speeding their translation into the clinic. We first discuss the major design principles and protocols for engineering various nanocomposites based on UCNP@SiO2 structures including those coated with dense silica, mesoporous silica, or hollow mesoporous silica. Next we summarize several representative efforts that probe the relaxivity mechanisms of these nanostructures as a way to optimize magnetic resonance sensitivity, multimode cancer imaging, near-infrared light-triggered chemotherapy, photodynamic therapy, and synergetic therapy (the combination of radiotherapy with chemotherapy, thermotherapy, or photodynamic therapy) using UCNP@SiO2-based theranostics. By rational integration of a wide range of features that convey multiple functions (such as imaging and therapy) into the structure or onto the surfaces of UCNP@SiO2, the constructed theranostics show promise for multimodal cancer imaging, biosensing, and effective cancer therapy. Finally, we discuss the limitations of UCNP@SiO2 nanostructures, the difficulties in the design of smart theranostics, and their potential role in clinical cancer research.

11.
Biotechnol Biotechnol Equip ; 29(2): 381-389, 2015 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-26019656

RESUMO

Surfactin, one of the most effective biosurfactants, has great potential in commercial applications. Studies on effective methods to reduce surfactin's production cost are always a hotspot in the research field of biosurfactants. The aim of this study was to reveal the role of Mn2+ in promoting the biosynthesis of surfactin by Bacillus subtilis ATCC 21332, which could arise more targeted suggestions on surfactin yield promotion. In this study, B.subtilis was cultivated in media containing different Mn2+ concentrations. The obtained results showed that the yield of surfactin gradually increased upon Mn2+ addition (0.001 to 0.1 mmol/L) and achieved the maximal production of 1500 mg/L, which reached 6.2-fold of the yield obtained in media without Mn2+ addition. Correspondingly, the usage ratios of ammonium nitrate were improved. When the Mn2+ concentration was higher than 0.05 mmol/L, nitrate became the main nitrogen source, instead of ammonium, indicating that the nitrogen utilization pattern was also changed. An increase in nitrate reductase activity was observed and the increase upon Mn2+ dosage had a positive correlate with nitrate use, and then stimulated secondary metabolic activity and surfactin synthesis. On the other hand, Mn2+ enhanced the glutamate synthase activity, which increased nitrogen absorption and transformation and provided more free amino acids for surfactin synthesis.

12.
Int J Surg ; 13: 227-238, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25527194

RESUMO

INTRODUCTION: Endoscopic minimal invasive cholecystolithotomy (EMIC) is recently popular in China which may offer advantages over laparoscopic cholecystectomy (LC). We try to find out the most favorable treatment for the patients underwent cholecystolithiasis. METHODS: Databases PubMed, Elsevier, Wiley Online Library, The Cochrane library, CNKI, WanFang Data, and Chongqing VIP were searched for randomized controlled trials (RCTs) and on EMIC vs LC from 2009 to 2013. Odds ratio (OR), risk difference (RD) and weight mean difference (WMD) were calculated with 95% confidence intervals (CI). RESULTS: 14 RCTs including 2030 patients were selected. No significant difference was present in operating time between EMIC and LC. EMIC shown significant less blood lost (WMD -23.45; 95% CI -30.34, -16.55; Z=6.66; P<0.00001) compared to LC. Shortened exhaust time (WMD -14.11; 95% CI -18.34, -9.88; Z=6.53; P<0.00001) and hospital stay (WMD -1.31; 95% CI -1.91, -0.71; Z=4.29; P<0.00001) were present in EMIC group. And EMIC shown decreased complication proportion (OR -0.14, 95% CI -0.09 to -0.21; Z=8.53; P<0.00001) in comparison with LC. There is no difference present in the recurrence of stones in two procedures but a significantly decreased recurrence rate of gallstones was present in EMIC compared to conventional cholecystolithotomy. CONCLUSION: Patients treated with EMIC shown faster recovery and less complication which were superior to LC.


Assuntos
Colecistectomia/métodos , Colecistolitíase/cirurgia , China , Colecistectomia Laparoscópica/métodos , Endoscopia do Sistema Digestório/métodos , Cálculos Biliares/cirurgia , Humanos , Tempo de Internação , Duração da Cirurgia
13.
Biomaterials ; 33(29): 7282-90, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22796158

RESUMO

Nuclear-targeted therapy by delivering anticancer drug directly into cancer cell nuclei can elicit synergistic therapeutic effects and kill these cancer cells with much enhanced efficiencies. Besides nuclear targeting, another difficulty in nuclear-targeted therapy is how to achieve real-time monitoring of the therapy process simultaneously. In this article we report on the development of multifunctional upconversion nanoparticles (UCNPs) which were able to target cancer cell nuclei, and thus deliver the anticancer drug directly to the nuclear region and simultaneously image cell nucleus by magnetic resonance (MR)/upconversion fluorescent for real-time guidance of their therapeutic action simultaneously. The Er/Yb-doped NaYF(4) core and NaGdF(4) shell endow the core/shell structured UCNPs with enhanced upconversion fluorescent imaging and more sensitive T(1)-MR imaging performances, and the surface conjugation of TAT peptide served as a key role in the nuclear targeting and nuclear transport process. This multifunctional UCNPs-based nano-theranostic was used to improve the efficacy of DOX in Hela humor tumor models, by direct DOX delivery to the nucleus under the synchronous monitoring of the nano-theranostics. Further development of this technology may provide more exciting opportunities in treating cancer disease by nuclear-targeted therapy.


Assuntos
Núcleo Celular/metabolismo , Sistemas de Liberação de Medicamentos , Imagem por Ressonância Magnética/métodos , Nanopartículas/química , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Meios de Contraste/farmacologia , Relação Dose-Resposta a Droga , Doxorrubicina/química , Células HeLa , Humanos , Camundongos , Microscopia Confocal/métodos , Microscopia Eletrônica de Transmissão/métodos , Microscopia de Fluorescência/métodos , Ácido Oleico/química , Peptídeos/química
14.
J Org Chem ; 74(4): 1549-56, 2009 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-19159243

RESUMO

With use of iodine as an appropriate oxidant, unprotected and unmodified aldoses undergo oxidative amidation with a variety of functionalized amines, alpha-amino esters, and peptides, whereas KDO, sialic acid, and other alpha-keto acids proceed with oxidative decarboxylation followed by in situ amidation. Glycoside bond and many other functional groups are inert under such mild reaction conditions. This reaction protocol for direct ligation of carbohydrate molecules looks promising in the development of a general and efficient synthesis of glycoconjugates.


Assuntos
Amidas/química , Cetoácidos/química , Monossacarídeos/química , Aminas/química , Ésteres/química , Iodo/química , Lactonas/química , Oxirredução , Peptídeos/química
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