Three-dimensional culture and clinical drug responses of a highly metastatic human ovarian cancer HO-8910PM cells in nanofibrous microenvironments of three hydrogel biomaterials.

BACKGROUND: Ovarian cancer is a highly aggressive malignant disease in gynecologic cancer. It is an urgent task to develop three-dimensional (3D) cell models in vitro and dissect the cell progression-related drug resistance mechanisms in vivo. In the present study, RADA16-I peptide has the reticulated nanofiber scaffold networks in hydrogel, which is utilized to develop robust 3D cell culture of a high metastatic human ovarian cancer HO-8910PM cell line accompanied with the counterparts of Matrigel and collagen I. RESULTS: Consequently, HO-8910PM cells were successfully cultivated in three types of hydrogel biomaterials, such as RADA16-I hydrogel, Matrigel, and collagen I, according to 3D cell culture protocols. Designer RADA16-I peptide had well-defined nanofiber networks architecture in hydrogel, which provided nanofiber cell microenvironments analogous to Matrigel and collagen I. 3D-cultured HO-8910PM cells in RADA16-I hydrogel, Matrigel, and collagen I showed viable cell proliferation, proper cell growth, and diverse cell shapes in morphology at the desired time points. For a long 3D cell culture period, HO-8910PM cells showed distinct cell aggregate growth patterns in RADA16-I hydrogel, Matrigel, and collagen I, such as cell aggregates, cell colonies, cell clusters, cell strips, and multicellular tumor spheroids (MCTS). The cell distribution and alignment were described vigorously. Moreover, the molecular expression of integrin ß1, E-cadherin and N-cadherin were quantitatively analyzed in 3D-cultured MCTS of HO-8910PM cells by immunohistochemistry and western blotting assays. The chemosensitivity assay for clinical drug responses in 3D context indicated that HO-8910PM cells in three types of hydrogels showed significantly higher chemoresistance to cisplatin and paclitaxel compared to 2D flat cell culture, including IC50 values and inhibition rates. CONCLUSION: Based on these results, RADA16-I hydrogel is a highly competent, high-profile, and proactive nanofiber scaffold to maintain viable cell proliferation and high cell vitality in 3D cell models, which may be particularly utilized to develop useful clinical drug screening platform in vitro.

Endoscopic anatomical study of the trans-lateral molar approach to the infratemporal fossa.

BACKGROUND: The infratemporal fossa (ITF) is located deep in the skull base. Recently, the endoscopic transoral approach has enabled maxillofacial surgeons to access the ITF using a less invasive approach compared to the traditional transfacial and endonasal endoscopic approaches. OBJECTIVE: The present study aims to provide maxillofacial surgeons with new data concerning direct endoscopic measurement and precise anatomical topography features of the endoscopic trans-lateral molar approach to ITF by comparing the endoscopic and regional anatomy of ITF. A clinical case receiving the proposed surgical approach is used to determine the feasibility of this technique. METHOD: The anatomical data were obtained by measuring the bone anatomical landmarks and analyzing the CT imaging data using GE's Advance Windows 4.1 software on 25 subjects (50 sides). Morphological pictures of the regional anatomy and endoscopic anatomy were obtained from 6 (12 sides) adult cadaver heads, and the anatomical features were described. The present study reports the management of one case using the proposed surgical approach. RESULTS: The proposed surgical approach clearly revealed neurovascular, muscular, and surgical landmarks in the ITF. The surgical case supports the minimally invasive treatment approach, which could rapidly access the ITF and completely excise benign tumors. CONCLUSION: The anatomical studies and surgical case presentation helps us understand the spatial relationship of surgical landmarks of the surgical approach to the ITF for the treatment of benign lesions in the deep cranial base area.

Comprehensive utilization of activated sludge for the preparation of hydrolytic enzymes, polyhydroxyalkanoates, and water-retaining organic fertilizer.

The urban wastewater treatment industry produces a large amount of excess activated sludge which is mainly composed of microbial biomass and costly to be disposed. In this research, a comprehensive utilization of activated sludge was developed by sequentially extracting hydrolytic enzymes and polyhydroxyalkanoates (PHAs), and the residue was used to prepare water-retaining organic fertilizer. The sludge was extracted with fourfold H2O-containing 1% Triton X-100 with the yield of 66.7% protease activity. The enzyme solution was precipitated in 80% acetone and vacuum dried at 40°C at the dried enzyme yield of 2.4 g/kg wet sludge. The enzyme product contains collagenase, lipase, amylase, and cellulase activities, which are good compound enzymes to feed. The PHAs were extracted with 30% sodium hypoclorite:chloroform (1:3). The PHA solution was decolored and dried, and pure white PHAs were obtained at the yield of 70.1 g/kg wet sludge. The residue was used to prepare water-retaining organic fertilizer at the optimal condition. The fertilizer absorbs 131.3-fold distilled water and had good performance in water retention and can effectively slow down the loss of soil moisture when added into soil. This work provides a simple and practical approach for comprehensive utilizing activated sludge with significant economic benefits.

Pf-Sp8/9, a novel member of the specificity protein family in Pinctada fucata, potentially participates in biomineralization.

Specificity protein (Sp) belong to a transcription factor family that contains nine subgroups with essential functions in development, including skeletogenesis, tooth development, neural tube closure, and limb formation. In molluscs, functions of the Sp protein family members have not been reported in detail. In this study, we report the first Sp protein-encoding gene in Pinctada fucata. We named the translated protein Pf-Sp8/9, based on the phylogenetic development tree constructed using Sp protein sequences from six model organisms, which showed that it was a Sp8/9 homolog. Alignment of the Pf-Sp8/9 sequence with the amino acid sequences of related proteins showed that Pf-Sp8/9 had conserved domains, including three DNA-binding motifs. The tissue distribution showed that while Pf-Sp8/9 mRNA expression was detected in all tested tissues, it was particularly high in the mantle. The luciferase reporter assay results showed that Pf-Sp8/9 had the ability to activate the transcription of a number of matrix proteins. The expression pattern of Pf-Sp8/9 during P. fucata pearl sac development was similar to that of some genes that encode matrix proteins, suggesting Pf-Sp8/9 may be involved in mantle-related physiological activities and biomineralization.

Surfactant-modified nanoclay exhibits an antiviral activity with high potency and broad spectrum.

UNLABELLED: Nanomaterials have the characteristics associated with high surface-to-volume ratios and have been explored for their antiviral activity. Despite some success, cytotoxicity has been an issue in nanomaterial-based antiviral strategies. We previously developed a novel method to fully exfoliate montmorillonite clay to generate the most fundamental units of nanoscale silicate platelet (NSP). We further modified NSP by capping with various surfactants and found that the surfactant-modified NSP (NSQ) was less cytotoxic. In this study, we tested the antiviral potentials of a series of natural-clay-derived nanomaterials. Among the derivatives, NSP modified with anionic sodium dodecyl sulfate (NSQc), but not the pristine clay, unmodified NSP, a silver nanoparticle-NSP hybrid, NSP modified with cationic n-octadecanylamine hydrochloride salt, or NSP modified with nonionic Triton X-100, significantly suppressed the plaque-forming ability of Japanese encephalitis virus (JEV) at noncytotoxic concentrations. NSQc also blocked infection with dengue virus (DEN) and influenza A virus. Regarding the antiviral mechanism, NSQc interfered with viral binding through electrostatic interaction, since its antiviral activity can be neutralized by Polybrene, a cationic polymer. Furthermore, NSQc reduced the lethality of JEV and DEN infection in mouse challenge models. Thus, the surfactant-modified exfoliated nanoclay NSQc may be a novel nanomaterial with broad and potent antiviral activity. IMPORTANCE: Nanomaterials have being investigated as antimicrobial agents, yet their antiviral potential is overshadowed by their cytotoxicity. By using a novel method, we fully exfoliated montmorillonite clay to generate the most fundamental units of nanoscale silicate platelet (NSP). Here, we show that the surfactant-modified NSP (NSQ) is less cytotoxic and that NSQc (NSP modified with sodium dodecyl sulfate) could potently block infection by dengue virus (DEN), Japanese encephalitis virus (JEV), and influenza A virus at noncytotoxic concentrations. For the antiviral mechanism, we find that the electrostatic interaction between the negatively charged NSQc and the positively charged virus particles blocks viral binding. Furthermore, we used mouse challenge models of JEV and DEN to demonstrate the in vivo antiviral potential of NSQc. Thus, NSQc may function as a potent and safe antiviral nanohybrid against several viruses, and our success in synthesizing surfactant-modified NSP with antiviral activity may shed some light on future antiviral development.

Effect of Slip Time in Forming Neo-Esophageal Stenosis After Replacement of a Thoracic Esophagus With Nitinol Artificial Esophagus.

Attempts have been made to investigate the effect of slip time of nitinol artificial esophagus for forming neo-esophageal stenosis after replacement of a thoracic esophagus with nitinol artificial esophagus in 20 experimental pigs. The pigs whose slip time was less than 90 days postoperatively had severe dysphagia (Bown's III) immediately after they were fed, and the dysphagia aggravated gradually later on (Bown's III-IV). The pigs whose slip time was more than 90 days postoperatively had mild/moderate dysphagia (Bown's I-II) immediately after they were fed, and the dysphagia relieved gradually later on (Bown's II-I-0). The ratios between the diameter of neo-esophagus in different slip time and normal esophagus were 25% (at 2 months postoperatively), 58% (at 4 months postoperatively), and 93% (at 6 months postoperatively), respectively. The relationship between nitinol artificial esophagus slip time and neo-esophageal stenosis showed a positive correlation. After replacement of a thoracic esophagus with nitinol artificial esophagus, the artificial esophageal slip time not only affected the original diameter of the neo-esophagus immediately, but also affected the neo-esophageal scar stricture forming process later on. The narrowing of neo-esophagus is caused by overgrowth of scar tissue. But there is the positive correlation between artificial esophagus slip time and neo-esophageal stenosis, so this can be a way of overcoming neo-esophageal stenosis by delaying slip time of artificial esophagus.

Evaluation of varying ductile fracture criteria for 42CrMo steel by compressions at different temperatures and strain rates.

Fracturing by ductile damage occurs quite naturally in metal forming processes, and ductile fracture of strain-softening alloy, here 42CrMo steel, cannot be evaluated through simple procedures such as tension testing. Under these circumstances, it is very significant and economical to find a way to evaluate the ductile fracture criteria (DFC) and identify the relationships between damage evolution and deformation conditions. Under the guidance of the Cockcroft-Latham fracture criteria, an innovative approach involving hot compression tests, numerical simulations, and mathematic computations provides mutual support to evaluate ductile damage cumulating process and DFC diagram along with deformation conditions, which has not been expounded by Cockcroft and Latham. The results show that the maximum damage value appears in the region of upsetting drum, while the minimal value appears in the middle region. Furthermore, DFC of 42CrMo steel at temperature range of 1123~1348 K and strain rate of 0.01~10 s(-1) are not constant but change in a range of 0.160~0.226; thus, they have been defined as varying ductile fracture criteria (VDFC) and characterized by a function of temperature and strain rate. In bulk forming operations, VDFC help technicians to choose suitable process parameters and avoid the occurrence of fracture.

Synthesis, characterization, and application of amino-terminated poly(ethylene glycol)-block-poly(epsilon-caprolactone) copolymer for paclitaxel.

In this paper, we successfully synthesized amino-terminated poly(ethylene glycol)-block-poly (epsilon-caprolactone) (NH2-PEG-PCL) block copolymer from polyethylene glycol 2000, epsilon-caprolactone (epsilon-CL) and hydrazine hydrate. The obtained copolymer was characterized by nuclear magnetic resonance (1H-NMR), the molecular weight and distribution of NH2-PEG-PCL were characterized by Gel permeation chromatography (GPC). The NH2-PEG-PCL copolymer could self-assemble into micelles in water. Paclitaxel (PTX) loaded NH2-PEG-PCL (PNPP) micelles were prepared by solid dispersion technique without organic solvent. The micelles were characterized by XRD, TEM and Malvern laser particle size. The results of this work indicated that PNPP micelles were uniform and spherical shapes in solution. The average size and zeta potential of PNPP (DL = 8%) in water was about 97.1 +/- 1.2 nm, +13.9 +/- 0.6 mV, respectively. The in vitrodrug release profile of PNPP micelles showed a clear slow-release effect. The results suggested that NH2-PEG-PCL copolymer might be an excellent carrier for hydrophobic drugs such as PTX. In particular, the NH2-PEG-PCL polymer has potential value for modifying with ligands to work as active targeting drug delivery carriers, which has great significance for cancer therapeutics.

High-birefringence, low-loss porous fiber for single-mode terahertz-wave guidance.

A new kind of polymer porous fiber with elliptical air-holes is designed for obtaining high birefringence in the terahertz (THz) frequency range in this paper. Using the finite element method, the properties of this kind of fiber are simulated in detail including the single-mode propagation condition, the birefringence, and the loss. Theoretical results indicate that the single-mode THz wave in the frequency range from 0.73 to 1.22 THz can be guided in the fiber; the birefringence can be enhanced by rotating the major axis of the elliptical air-hole and there exists an optimal rotating angle at 30°. At this optimal angle a birefringence as high as 0.0445 can be obtained in a wide frequency range. Low-loss THz guidance can be achieved owing to the effective reduction of the material absorption in such a porous fiber. This research is useful for polarization-maintaining THz-wave guidance.

Paroxysmal tonic upgaze accompanied by occipital discharge on electroencephalography: a case report and literature review.

BACKGROUND: Paroxysmal tonic upgaze (PTU) is an infantile-onset paroxysmal neurological disorder that is characterized by episodes of sustained conjugate upward eye deviation. The paroxysmal abnormal eye movements need to be differentiated from seizures. We report a case of PTU with occipital discharge on electroencephalography (EEG), which made the diagnosis more complicated. CASE PRESENTATION: A 6-month-old girl presented with paroxysmal upward deviation or left strabismus of the eyes, with a bowed head, lowered jaw, raised eyebrows, closed lips, and slight grin. Each episode lasted for a few seconds, and episodes occurred multiple times per day. EEG showed spike waves in the right occipital region, and the girl was initially misdiagnosed with epilepsy. After further analysis using video EEG, we corrected her diagnosis as PTU and stopped the administration of an antiepileptic drug. CONCLUSION: PTU accompanied by discharge on EEG may lead to a misdiagnosis. Video EEG monitoring, and especially the analysis of EEG traces synchronized with attacks, can provide evidence to distinguish between seizures and non-epileptic events.

Experimental Study of the Tissue Repair of Neo-Esophagus After Esophageal Muscularis Resection.

Attempts have been made to observe the tissue repair of neo-esophagus after esophageal muscularis resection and to investigate possibility of the regeneration repair of esophageal muscularis resection in neo-esophagus. Sixteen pigs were divided into two groups: group A and group B. Pigs in group A were performed with the partial resection of mere esophageal muscularis propria reserved mucosa muscle layer in a segment of thoracic esophagus. Pigs in group B were performed with nitinol composite artificial esophagus with polyester sewing rings replacement a segment of thoracic esophagus resection. Pigs in the two groups were performed with euthanasia at the following times: 2, 4, 6, and 12 months for postmortem analysis, which demonstrated the absence of esophageal muscularis regeneration in the specimens that were sampled from different time points. Reserved mucosa muscle layer did not show hyperplasia to repair coloboma of esophageal muscularis propria deletion in group A. These results suggest that after esophageal muscularis resection, including mucosa muscle layer or esophageal muscularis propria, the coloboma of esophageal muscularis was repaired with connective tissue filling quickly. It would be very difficult for the regeneration repair of esophageal muscularis in neo-esophageal tissue structure after esophageal muscularis resection.

Does PGA external stenting reduce compliance mismatch in venous grafts?

BACKGROUND: Autogenous vein grafting is widely used in regular bypassing procedures. Due to its mismatch with the host artery in both mechanical property and geometry, the graft often over expands under high arterial blood pressure and forms a step-depth where eddy flow develops, thus causing restenosis, fibrous graft wall, etc. External stents, such as sheaths being used to cuff the graft, have been introduced to eliminate these mismatches and increase the patency. Although histological and immunochemical studies have shown some positive effects of the external stent, the mechanical mismatch under the protection of an external stent remains poorly analyzed. METHODS: In this study, the jugular veins taken from hypercholesterolemic rabbits were transplanted into the carotid arteries, and non-woven polyglycolic acid (PGA) fabric was used to fabricate the external stents to study the effect of the biodegradable external stent. Eight weeks after the operation, the grafts were harvested to perform mechanical tests and histological examinations. An arc tangent function was suggested to describe the relationship between pressure and cross-sectional area to analyse the compliance of the graft. RESULTS: The results from the mechanical tests indicated that grafts either with or without external stents displayed large compliance in the low-pressure range and were almost inextensible in the high-pressure range. This was very different from the behavior of the arteries or veins in vivo. The data from histological tests showed that, with external stents, collagen fibers were more compact, whilst those in the graft without protection were looser and thicker. No elastic fiber was found in either kind of grafts. Furthermore, grafts without protection were over-expanded which resulted in much bigger cross-sectional areas. CONCLUSION: The PGA external extent contributes little to the reduction of the mechanical mismatch between the graft and its host artery while remodeling develops. For the geometric mismatch, it reduces the cross-section area, therefore matching with the host artery much better. Although there are some positive effects, conclusively the PGA is not an ideal material for external stent.

A template route to the preparation of mesoporous amorphous calcium silicate with high in vitro bone-forming bioactivity.

The mesoporous amorphous calcium silicate (MACS) was first synthesized using mesoporous silica SBA-15 as both the template and silicon source, and Ca(NO(3))(2) as the calcium source. The MACS shows a well-defined mesoporous structure with high specific surface area. In vitro bioactivity studies of the MACS were carried out by soaking it in simulated body fluid (SBF) solutions for 4 h up to 5 days. Owing to the high specific surface area and pore volume, the MACS had a significantly enhanced bone-forming bioactivity compared with the conventional amorphous CaSiO(3). The MACS did develop a carbonate-containing hydroxyapatite (HCA) layer on the surface after being immersed in SBF for 4 h with near-spherical agglomerated hydroxyapatite (HA) nanoparticles. At longer soaking times, the number of agglomerated HA particles increased and the surface structure of the samples became more compact. Such MACS could be useful in developing new biomaterials and may have potential use in implanting and drug delivery for tissue regeneration.

Direct Macromolecular Drug Delivery to Cerebral Ischemia Area using Neutrophil-Mediated Nanoparticles.

Delivery of macromolecular drugs to the brain is impeded by the blood brain barrier. The recruitment of leukocytes to lesions in the brain, a typical feature of neuroinflammation response which occurs in cerebral ischemia, offers a unique opportunity to deliver drugs to inflammation sites in the brain. In the present study, cross-linked dendrigraft poly-L-lysine (DGL) nanoparticles containing cis-aconitic anhydride-modified catalase and modified with PGP, an endogenous tripeptide that acts as a ligand with high affinity to neutrophils, were developed to form the cl PGP-PEG-DGL/CAT-Aco system. Significant binding efficiency to neutrophils, efficient protection of catalase enzymatic activity from degradation and effective transport to receiver cells were revealed in the delivery system. Delivery of catalase to ischemic subregions and cerebral neurocytes in MCAO mice was significantly enhanced, which obviously reducing infarct volume in MCAO mice. Thus, the therapeutic outcome of cerebral ischemia was greatly improved. The underlying mechanism was found to be related to the inhibition of ROS-mediated apoptosis. Considering that neuroinflammation occurs in many neurological disorders, the strategy developed here is not only promising for treatment of cerebral ischemia but also an effective approach for various CNS diseases related to inflammation.

[Experimental study of replacement of an esophageal segment with an nitinol alloy composite artificial esophagus].

OBJECTIVE: To observe the feasibility of a segment thoracic esophagus replaced by using a nitinol alloy composite artificial esophagus. METHODS: A nitinol alloy composite artificial esophagus was made of a nitinol tube coated with a silicone membrane with a dacron flange 1 cm proximal to each end. There were ten pigs for the models of experimental animal. The models of experimental animal were established by excised a segment of 7 cm long thoracic esophagus and replaced with the graft. In accordance with the different anastomosis connective way 10 pigs were divided into group I and group II, every group had 5 pigs. In group I monolayer end-to-end anastomosis was used with this prosthesis. In group II monolayer end-to-end anastomosis was used with this prosthesis and above the site of anastomosis adding dacron strip fixed. After operation the operate animals were observed for eating and health. Esophagography and flexible esophagoscopy were performed once a month at the first, second, and third postoperatively month. Three pigs of the grafted prostheses sloughed out spontaneously at different postoperatively period were killed for autopsy and pathologic examination of the neoesophagus. RESULTS: All pigs had no leakage at the site of anastomosis and survived over 6 months. The longest survival was 20 months. Seven of 10 pigs the grafted prostheses sloughed out spontaneously at 2 to 6 months after the operation (4 in group I and 3 in group II). The grafted prostheses sloughed out spontaneously less than 3 months after operation, marked neoesophageal stenosis in the grafted portion was recognized (3 in group I). They displayed serious difficulty in eating. But the prostheses sloughed out spontaneously more than 3 months after operation, neoesophageal stenosis was increased slightly and the stenosis was only temporary and gradually resolved. (1 in group I, 3 in group II) They lived in good health and without difficulty in eating. Three of 10 pigs the grafted prosthesis still stayed in the grafted place over 10 months (1 in group I, 2 in group II). The neoesophageal had no stenosis. They were perfectly well in eating. CONCLUSIONS: A segment excised pig esophagus replaced with a nitinol alloy composite artificial esophagus is feasible and takes a better result.

[Studies on chemical constituents of Paederia scandense].

OBJECTIVE: To study the chemical constituents of Paederia scandense. METHOD: The constituents were isolated and purified by silica gel and Sephadex LH - 20 column chromatography. Their structures were elucidated by physicochemical properties and spectral analysis. RESULT: 20 compounds were obtained and identified as rubiadin-1-methylether (1), diadzein (2), cleomiscosin B (3), cleomiscosin D (4), isolariciresinol (5), linarin (6), isoscopoletin (7), caffic acid (8), coumarinic acid (9), p-hydroxyl-benzoic acid (10), oleanolic acid (11), ursolic acid (12), beta-sitosterol (13), daucosterol (14), paederoside (15), paederosidic acid (16), paederosidic acid methyl ester (17), saprosmoside E (18), paederoscandoside (19), caffeic acid 4-O-beta-D-glucopyranoside (20). CONCLUSION: Compounds 1-10, and 20 were isolated from this plant for the first time.

Intraoral lining with the fibular osteomyofascial flap without a skin paddle during maxillary and mandibular reconstruction.

BACKGROUND: To achieve an ideal intraoral lining, we harvest the fibular osteomyofascial flap to avoid the common embarrassment caused by the fibular osteomyocutaneous flap, and we report on our experience with this technique in this article. METHODS: Twenty-eight patients underwent reconstruction of the maxilla and mandible using an osteomyofascial free fibula flap after oncologic ablation. Data, including the size of the fascial flaps, the number of debulking operations, the complications at both the donor and recipient sites, and the dental rehabilitation, were collected. RESULTS: All fascial flaps survived and were remucosalized, except one with partial necrosis. None of the patients in the osteomyofascial group required an additional debulking operation, and 82% of the patients (23 of 28) had conventional dentures and showed good chewing function and cosmetic results. CONCLUSION: The fibular osteomyofascial flap yielded a more anatomic solution for oral mucosal defects, obviating the need for additional debulking and potentially reducing donor-site wound problems. © 2015 Wiley Periodicals, Inc. Head Neck 38: E832-E836, 2016.

Preparation and characterization of overcoated II-VI quantum dots.

A convenient route for the synthesis of high-quality overcoated II-VI quantum dots (QDs) is reported in this paper. Simple salts, such as Cd(Ac)2 and Zn(Ac)2 were used to replace organometallics, whose disadvantage is obvious. Size-tunable core/shell structured QDs (CdSe/ZnS, CdSe/CdS, etc.) were synthesized. They were of narrow size distribution and had good monodispersivity and photoluminescence (PL) properties. The spectrum was symmetrical and sharp-pointed (with the full width at half-maximum (fwhm) of about 20-30 nm). The quantum yield (QY) was improved to 60-80% from 20-30% for bare QDs and remained stable at least for 6 months. The primary overcoated QDs were modified with biomacromolecules by a direct mechanical rubbing strategy, which is very simple and fast. The results obtained by UV-vis, PL, atomic force microscopy (AFM), and fluorescence microscopy imaging showed that the modified QDs were of good fluorescent and monodisperse characteristics. They are likely to be used further for biological labels.

Metabolic Engineering of Escherichia coli for Poly(3-hydroxybutyrate) Production under Microaerobic Condition.

The alcohol dehydrogenase promoter PadhE and mixed acid fermentation pathway deficient mutants of Escherichia coli were employed to produce poly(3-hydroxybutyrate) (P3HB) under microaerobic condition. The E. coli mutant with ackA-pta, poxB, ldhA, and adhE deletions accumulated 0.67 g/L P3HB, up to 78.84% of cell dry weight in tube cultivation. The deletion of pyruvate formate-lyase gene pflB drastically decreased P3HB production and P3HB content to 0.09 g/L and 24.44%, respectively. Overexpressing pflB via the plasmid in its knocked out mutant restored cell growth and P3HB accumulation, indicating the importance of the pyruvate formate-lyase in microaerobic carbon metabolism. The engineered E. coli BWapld (pWYC09) produced 5.00 g/L P3HB from 16.50 g/L glucose in 24 h batch fermentation, and P3HB production yield from glucose was 0.30 g/g, which reached up to 63% of maximal theoretical yield.

Anti-tumor activity and safety evaluation of fisetin-loaded methoxy poly(ethylene glycol)-poly(epsilon-caprolactone) nanoparticles.

Fisetin (3,3',4',7-tetrahydroxyflavone) is a potential anti-tumor agent but poor water solubility hinders its application and complicates direct parenteral administration. Nanoparticle encapsulation is an efficient way to enhance the solubility of some hydrophobic drugs. In this study, methoxy poly(ethylene glycol)-polycaprolactone (MPEG-PCL) nanoparticles were successfully prepared for fisetin delivery in vitro and in vivo. Narrow distribution fisetin-loaded MPEG-PCL NPs (aproximately100 nm) were obtained via emulsification (O/W) and displayed a sustained release behavior in vitro. Moreover, hemolysis and cell cytotoxicity testing showed that MPEG-PCL is biocompatible and safe for intravenous injection. Most importantly, NPs encapsulation enhanced the anti-cancer activity of fisetin as shown in a subcutaneous LL/2 tumor model, and reduced the hepatotoxicity of fisetin. Therefore, our data demonstrate that fisetin-loaded MPEG-PCL NPs have potential application in cancer chemotherapy.