Postharvest benzothiazole treatment enhances healing in mechanically damaged sweet potato by activating the phenylpropanoid metabolism.

BACKGROUND: Sweet potato often suffers mechanical damage during harvest, handling, and transportation. Infections, water loss, and quality changes of sweet potato caused by mechanical damage pose great financial losses. Wound healing is an effective method to alleviate such problems. In this study, the effects of postharvest treatment with benzothiazole (BTH) on wound healing of sweet potato was investigated. RESULTS: Postharvest BTH treatment of sweet potatoes promoted lignin accumulation in wounded tissues, and 100 mg L-1 BTH exhibited better effects than 50 mg L-1 or 150 mg L-1 BTH. The biosynthesis of lignin in wounded tissues significantly decreased the weight loss of sweet potatoes. An increase in respiration intensity after BTH treatment was observed. The total phenolic and flavonoid contents and the activity of phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase were increased in BTH-treated sweet potatoes. This suggests that BTH increases phenylpropanoid metabolism. CONCLUSION: Postharvest 100 mg L-1 BTH treatment could promote wound healing in mechanically damaged sweet potatoes. The activation of the phenylpropanoid metabolism might be the mechanism of action of BTH in wound healing. © 2020 Society of Chemical Industry.

[Investigation and optimization on ability of enzymatic hydrolysis of Mori Cortex residue].

Residue of Mori Cortex was studied to optimize its enzymatic hydrolysis process, and explore its potential as a carbon source for biochemistry and biofuel production. The cellulose content of diluted acid pretreated (DAP) and non-pretreated from Mori Cortex were measured in this study, and the results showed that the cellulose content of DAP and non-pretreated from Mori Cortex were 52.5% and 47%, respectively. This higher cellulose content indicated that residue of Mori Cortex had the potential to act as a carbon source for biochemistry and biofuel production. Enzymatic hydrolysis of pretreated and non-pretreated from Mori Cortex was conducted under different enzyme loading amount. 40 FPU·(g DW）⁻¹ enzyme loading was determined as the optimal amount by comparing the yield of sugar and the rate of enzymolysis. Under this condition, the concentrations of glucose, xylose, arabinose sugar were 23.82, 4.84, 3.6 g·L⁻¹, and the corresponding enzymatic hydrolysis rate was 45.33% which was 2.3 times higher than that of non-pretreated from Morus alba residues. Fed-batch enzymatic hydrolysis was conducted finally to get higher sugar yield, and the final glucose concentration reached up to 38 g·L⁻¹ with the enzymatic hydrolysis rate of 36.19%. The results indicated that Mori Cortex residue had higher cellulose and hemicellulose contents, so it had the potential to become a carbon source to produce the bio-chemicals and biofuels. Through enzymatic hydrolysis, it can be converted into microbial available monosaccharides; and through fermentation, it can be converted into high value-added chemicals, biofuels, etc., to solve the problem of residue pollution, and achieve the sustainable development and greening of Chinese pharmaceutical production process.

Comparative toxicity of nonylphenol, nonylphenol-4-ethoxylate and nonylphenol-10-ethoxylate to wheat seedlings (Triticum aestivum L.).

Nonylphenol polyethoxylates (NPEOs) are a group of surfactants that are widely used in industrial and household products and often detected in the environment. The metabolite of NPEOs, named nonylphenol (NP), has proven to be an endocrine disruptor, and its environmental behavior and eco-toxicity have been widely investigated in previous studies. However, to the best of our knowledge, insight into the toxicity differences of NP and NPEOs on important crops remains limited. Therefore, this study investigated the comparative toxicity of NP, nonylphenol-4-ethoxylate (NP4EO), and nonylphenol-10-ethoxylate (NP10EO) on wheat seedlings using hydroponic experiments. The results indicated that NP is most toxic to wheat followed by NP4EO, and NP10EO is the least toxic to wheat. The adverse effects of NP on wheat were observed for all the tested parameters including germination, shoot length, root length, chlorophyll, lipid peroxidation, and enzymatic activities. To gain insight into the molecular response, we analyzed the transcript abundance of SOD-Cu/Zn and CAT with NP, NP4EO, and NP10EO exposure using quantitative real-time PCR. The data revealed that both genes exhibited up- or down-regulated expression patterns that were consistent with the activities of the two enzymes. This result further conformed that NP is most toxic to wheat plants.

Acibenzolar-S-methyl promotes wound healing of harvested sweet potatoes (Ipomoea batatas) by regulation of reactive oxygen species metabolism and phenylpropanoid pathway.

Rapid wound healing is crucial in protecting sweet potatoes (Ipomoea batatas ) against infection, water loss and quality deterioration during storage. The current study investigated how acibenzolar-S-methyl (ASM) treatment influenced wound healing in harvested sweet potatoes by investigating the underlying mechanism. It was found that ASM treatment of wounded sweet potatoes induced a significant accumulation of lignin at the wound sites, which effectively suppressed weight loss. After 4days of healing, the lignin content of ASM-treated sweet potatoes was 41.8% higher than that of untreated ones, and the weight loss rate was 20.4% lower. Moreover, ASM treatment increased the ability of sweet potatoes to defend against wounding stress through enhancing processes such as increased production of reactive oxygen species (ROS), activation of enzymes involved in the ROS metabolism (peroxidase, superoxide dismutase and catalase) and phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coumarate-CoA ligase and cinnamyl alcohol dehydrogenase), and intensive synthesis of phenolics and flavonoids. These results suggest that treating harvested sweet potatoes with ASM promotes wound healing through the activation of the ROS metabolism and phenylpropanoid pathway.

Transfer from ciliate to zebrafish: Unveiling mechanisms and combined effects of microplastics and heavy metals.

The impacts and toxicological mechanisms of microplastics (MPs) or heavy metals on aquatic ecosystems have been the subject of extensive research and initial understanding. However, the combined toxicity of co-pollutants on organisms and cumulative toxic effects along the food chain are still underexplored. In this study, the ciliate protozoan Paramecium caudatum and zebrafish Danio rerio were used to represent the microbial loop and the higher trophic level, respectively, to illustrate the progressive exposure of MPs and cadmium (Cd2+). The findings indicate that MPs (ca. 1 ×105 items/L) containing with Cd2+ (below 0.1 µg/L) could permeate the bodies of zebrafish through trophic levels after primary ingestion by ciliates. This could cause adverse effects on zebrafish, including alterations in bioindicators (total sugar, triglycerides, lactate, and glycogen) associated with metabolism, delayed hepatic development, disruption of intestinal microbiota, DNA damage, inflammatory responses, and abnormal cellular apoptosis. In addition, the potential risks associated with the transfer of composite pollutants through the microbial loop into traditional food chain were examined, offering novel insights on the evaluation of the ecological risks associated with MPs. As observed, understanding the bioaccumulation and toxic effects of combined pollutants in zebrafish holds crucial implications for food safety and human health.

Distinct distribution patterns and functional potentials of rare and abundant microorganisms between plastisphere and soils.

The increasing application of plastic film has caused the "white pollution" of farmlands in greenhouses. To date, most studies on the ecology of the plastisphere have focused on the whole microbial community, with few on the rare and abundant taxa, especially in the terrestrial ecosystems. To understand the plastisphere rare and abundant taxa of bacterial and fungal communities, we collected residues of plastic film from plastic-covered soils in the greenhouse. The plastisphere was significantly different from surrounding soils in terms of alpha- and beta-diversities of abundant and rare taxa. Such discrepancies were greater in rare taxa than in abundant taxa. Besides, the enrichment of soil-borne plant pathogenic fungi in the plastisphere implied that plastic film residues can act as vectors for pathogen transmission. In the plastisphere, the stochastic process governed the assemblies of rare taxa, while deterministic assemblies dominated that of abundant taxa. However, in surrounding soils, the stochastic process played a larger role in abundant taxa as compared to rare taxa. The plastisphere showed a network of less complexity, more competitive connections, and more modules compared to surrounding soils, and rare taxa played greater roles than abundant taxa. There existed obvious discrepancies in the microbial functions between surrounding soils and plastisphere, including carbon, sulfur, nitrogen, and phosphorus cycling, and rare taxa contribute large proportions to the above cycling processes. Altogether, the findings advance our understanding of ecological mechanisms of abundant and rare taxa in the plastisphere in terrestrial ecosystems.

High-solids enzymatic saccharification of starch-rich raw herbal biomass residues for producing high titers of glucose.

The bioresource utilization of herbal biomass residues (HBRs) has been receiving more attention. Herein, three different HBRs from Isatidis Radix (IR) and Sophorae Flavescentis Radix (SFR) and Ginseng Radix (GR) were subjected to batch and fed-batch enzymatic hydrolysis to produce high-concentration glucose. Compositional analysis showed the three HBRs had substantial starch content (26.36-63.29%) and relatively low cellulose contents (7.85-21.02%). Due to their high starch content, the combined action of cellulolytic and amylolytic enzymes resulted in greater release of glucose from the raw HBRs compared to using the individual enzyme alone. Batch enzymatic hydrolysis of 10% (w/v) raw HBRs with low loadings of cellulase (≤ 10 FPU/g substrate) and amylolytic enzymes (≤ 5.0 mg/g substrate) led to a high glucan conversion of ≥ 70%. The addition of PEG 6000 and Tween 20 did not contribute to glucose production. Furthermore, to achieve higher glucose concentrations, fed-batch enzymatic hydrolysis was conducted using a total solid loading of 30% (w/v). After 48-h of hydrolysis, glucose concentrations of 125 g/L and 92 g/L were obtained for IR and SFR residues, respectively. GR residue yielded an 83 g/L glucose concentration after 96 h of digestion. The high glucose concentrations produced from these raw HBRs indicate their potential as ideal substrate for a profitable biorefinery. Notably, the obvious advantage of using these HBRs is the elimination of the pretreatment step, which is typically required for agricultural and woody biomass in similar studies.

Sulfosalicylate mediates improved vinorelbine loading into LUVs and antineoplastic effects.

Liposomal vinorelbine formulation is desirable, as it might improve the therapeutic activity of vinorelbine. However, because of its lipophilic and membrane-permeable properties, vinorelbine is hard to be formulated into liposomes using conventional drug-loading technologies. To improve vinorelbine retention, ammonium salts of several anionic agents were employed to prepare liposomal vinorelbine formulations. It was found that 5-sulfosalicylate (5ssa) could form stable complexes with vinorelbine and stabilize entrapped vinorelbine. The resultant vesicles had an in vitro release t(1/2) of ~12.49 hours in NH(3)-containing media, which is longer than those of sulfate and phytate vesicles (~0.57 hours). The circulation half-life of vinorelbine after the injection of 5ssa vesicles into normal mice was ~13.01 hours, accounting for ~2-fold increase relative to that of sulfate vesicles. Improved drug retention correlated with enhanced antitumor efficacy. In the RM-1/c57 model, 5ssa vesicles were more efficacious than sulfate vesicles (P < 0.05). In RM-1/BDF1 and Lewis lung cancer/c57 models, antitumor efficacy was also considerably improved after vinorelbine encapsulation into 5ssa vesicles. For instance, in the RM/BDF1 model, liposomal vinorelbine was at least 4-fold more therapeutically active than free vinorelbine. Our results demonstrated that 5ssa could stabilize vinorelbine relative to other anions, resulting in the formulation with improved drug retention and efficacy. Improved vinorelbine retention might be associated with the formation of insoluble precipitate, which could be proved by precipitation study and decreased drug-release rate at a high D/L ratio.

Rapid initiation of a single-stage partial nitritation-anammox process treating low-strength ammonia wastewater: Novel insights into biofilm development on porous polyurethane hydrogel carrier.

Media-supported biofilm is a powerful strategy for growth and enrichment of slow-growing microorganisms. In this study, a single-stage nitritation-anammox process treating low-strength wastewater was successfully started to investigate the biofilm development on porous polyurethane hydrogel carrier. Suspended biomass migration into the carrier and being entrapment by its internal interconnected micropores dominated the fast initial colonization stage. Both surface-attached growth and embedded growth of microbes occurred during the following accumulation stage. Fluorescence in situ hybridization analysis of mature biofilm indicated that ammonium-oxidizing bacteria located at the outer layers featured a surface-attached growth, while anammox microcolonies housed in the inner layers proliferated as an embedded-like growth. In this way, the growth rate of anammox bacteria (predominated by Candidatus Kuenenia) could be 0.079 d-1. The anammox potential of the biofilm reactor reached 1.65 ± 0.3 kg/m3/d within two months. This study provides novel insights into nitritation-anammox biofilm formation on the porous polyurethane hydrogel carrier.

An Albumin-Based Therapeutic Nanosystem for Photosensitizer/Protein Co-Delivery to Realize Synergistic Cancer Therapy.

Oxygen-dependent photodynamic therapy (PDT) is hindered by the limited availability of endogenous oxygen in solid tumors and low tumor accumulation of photosensitizers. Herein, we developed a biocompatible cancer-targeted therapeutic nanosystem based on cRGD conjugated bovine serum albumin (CBSA) co-loaded with a photosensitizer (chlorin e6, Ce6) and a therapeutic protein (cytochrome c, Cytc) for synergistic photodynamic and protein therapy. The nanosystem (Ce6/Cytc@CBSA) can target αVß3 integrin overexpressed cancer cells to improve tumor accumulation due to incorporation of cRGD. In the intracellular environment, Ce6 is released to produce toxic singlet oxygen upon near-infrared irradiation. At the same time, the therapeutic protein, Cytc, can induce programmed cell death by activating the downstream caspase pathway. Most importantly, Cytc with the catalase-like activity accelerates O2 generation by decomposing excess H2O2 in cancer cells, thereby relieving the PDT-induced hypoxia to enhance therapeutic efficacy. Both in vitro and in vivo studies reveal the significantly improved antitumor effects of the combined photodynamic/protein therapy, indicating that Ce6/Cytc@CBSA shows great potential in synergetic cancer treatments.

[Pharmacodynamics, pharmacokinetics and tissue distribution of liposomal mitoxantrone hydrochloride].

This study is to compare the pharmacodynamics, pharmacokinetics and tissue distribution of liposomal mitoxantrone (Mit-lipo) and free mitoxantrone (Mit-free). The antineoplastic effect of Mit-lipo was evaluated on PC-3 human xenograft tumor model after repeated intravenous injection at dose levels of 1, 2 and 4 mg x kg(-1). The pharmacokinetic study of Mit-lipo and Mit-free was performed on dogs following a single intravenous injection. The tissue distribution of Mit-lipo and Mit-free was observed on S-180 bearing mice after a single intravenous injection. (1) Pharmacodynamics: Mit-lipo dose-dependently inhibited PC-3 tumor growth at a dose ranging from 1 to 4 mg x kg(-1). The antitumor effect studies showed that Mit-lipo significantly improved the therapeutic effect in comparison with free drug. (2) Pharmacokinetics: in comparison with Mit-free, the AUC and t(1/2) values of Mit-lipo at the same dose level were higher than those of Mit-free in Beagle dogs. The results showed that Mit-lipo had long circulation characteristics. (3) Tissue distribution in S-180 bearing mice: compared to Mit-free, Mit-lipo preferentially accumulated into tumor zones instead of normal tissues. Tumor AUC in Mit-lipo treated animals was 8.7 fold higher than that in mice treated with the same dose of Mit-free. The Cmax values of Mit-lipo in heart, kidney, lung, spleen and intestinal tissue in Mit-lipo were 30.2%, 161.6%, 20.2%, 27.9% and 78.3% lower than those of Mit-free, respectively. The pharmacokinetics and tissue distribution of Mit-lipo changed obviously, thus increasing therapeutic effect and improving drug therapeutic index.

Biotinylated and fluorophore-incorporated polymeric mixed micelles for tumor cell-specific turn-on fluorescence imaging of Al3.

Excessive amounts of Al3+ in the human body can cause adverse effects on immune function and induce several neurodegenerative disorders. So far, most of the reported fluorescent probes for Al3+ present some common drawbacks, such as low sensitivity and poor water solubility. In addition, a number of traditional fluorescent probes failed to image Al3+ in tumor cells due to the lack of tumor cell targeting capacity and cell penetrating abilities. To overcome these shortcomings, we constructed tumor-targeting fluorescent mixed nano-micelles (mPEG-Dye-Biotin) with an average particle size of 21 nm from an amphiphilic polymer containing a Schiff-base fluorescent unit (mPEG-Dye) and another amphiphilic polymer containing a tumor cell recognition ligand (DSPE-PEG-Biotin), through the co-self-assembly of both amphiphilic polymers in water using the film rehydration method. The as-prepared nanoprobe showed a highly sensitive and selective turn-on fluorescence response to Al3+ in aqueous solution with a low detection limit. MTT assay revealed the negligible cytotoxicity of the mPEG-Dye-Biotin nanoprobe to both HeLa cells and COS-7 cells, indicating the safety of mPEG-Dye-Biotin for biological applications. More importantly, the biotinylated nanoprobe showed better ability to enter biotin receptor-positive HeLa cells than that of the non-biotinylated micelle mPEG-Dye, which made it more suitable for imaging Al3+ in biotin receptor-positive tumor cells. This work provides a simple and general strategy to design a highly sensitive and tumor cell-specific metal ion nanoprobe, which can not only be applied in Al3+ imaging, but can also be extended to other ions or biomolecules by changing the incorporated fluorescent unit in the amphiphilic polymer.

Effect of Poly(ethylene glycol) (PEG) Surface Density on the Fate and Antitumor Efficacy of Redox-Sensitive Hybrid Nanoparticles.

The effects of poly(ethylene glycol) (PEG) on improving the biological compatibility and circulation time of nanocarriers are determined by the surface density of PEG on nanoparticles. PEG with high surface density on nanocarriers has greater accumulation in tumor tissues. However, this impairs the release of drugs loaded in the nanoparticles in the tumor tissues. The relations and internal regularities between the controlled stripping of PEG of nanoparticles and its fate and antitumor efficacy in vivo remain unsolved. Redox-sensitive hybrid nanoparticles coated with varied PEG densities were prepared by blending a redox-sensitive polymer of DLPE-SS-MPEG. To keep identical nanoproperties, these nanoparticles were prepared with a similar size distribution of around 100 nm. The effects of controlled stripping of PEG on antitumor activities of nanoparticles were then investigated. As the PEG surface density increased, lower cellular internalization by tumor cells was observed. However, nanoparticles with higher controlled stripping of PEG showed greater accumulation in tumor tissues and advanced antitumor activities in vivo.

Multiplex detection of six swine viruses on an integrated centrifugal disk using loop-mediated isothermal amplification.

Advances in molecular testing and microfluidic technologies have opened new avenues for rapid detection of animal viruses. We used a centrifugal microfluidic disk (CMFD) to detect 6 important swine viruses, including foot-and-mouth disease virus, classical swine fever virus, porcine reproductive and respiratory swine virus-North American genotype, porcine circovirus 2, pseudorabies virus, and porcine parvovirus. Through integrating the loop-mediated isothermal amplification (LAMP) method and microfluidic chip technology, the CMFD could be successfully performed at 62℃ in 60 min. The detection limit of the CMFD was 3.2 × 102 copies per reaction, close to the sensitivity of tube-type LAMP turbidity methods (1 × 102 copies per reaction). In addition, the CMFD was highly specific in detecting the targeted viruses with no cross-reaction with other viruses, including porcine epidemic diarrhea virus, transmissible gastroenteritis virus, and porcine rotavirus. The coincidence rate of CMFD and conventional PCR was ~94%; the CMFD was more sensitive than conventional PCR for detecting mixed viral infections. The positive detection rate of 6 viruses in clinical samples by CMFD was 44.0% (102 of 232), whereas PCR was 40.1% (93 of 232). Thirty-six clinical samples were determined to be coinfected with 2 or more viruses. CMFD can be used for rapid, sensitive, and accurate detection of 6 swine viruses, offering a reliable assay for monitoring these pathogens, especially for detecting viruses in widespread mixed-infection clinical samples.

Encapsulation of mitoxantrone into pegylated SUVs enhances its antineoplastic efficacy.

Mitoxantrone (MIT) was encapsulated into 60, 80 and 100nm pegylated hydrogenated soy phosphatidylcholine/cholesterol (HSPC/chol) vesicles using a transmembrane (NH(4))(2)SO(4) gradient. In-vitro release studies revealed that small-sized formulation had fast drug-release rate. Acute toxicity studies performed in c57 mice proved that all pegylated liposomal MIT (plm) formulations could be well-tolerated at a dose of 9mg/kg, significantly compared to severe toxicity induced by free mitoxantrone (f-M). In KM mice, plm60 was at least 2- to 3-fold less toxic than f-M. After intravenous injection, plm60 was slowly eliminated from plasma relative to f-M, resulting in about 6459-fold increase in AUC and its plasma kinetics exhibited dose dependence. In S-180 bearing KM mice, plm60 preferentially accumulated into tumor zone, with a approximately 12-fold increase in AUC and approximately 10-fold increase in C(max) Furthermore, the accumulation of plm60 in almost all normal tissues markedly decreased. The antitumor efficacy of plm60 was also considerably enhanced. In L1210 ascitic tumor model, plm60 was the most efficacious which led to a approximately 70% long-term survival, significantly compared to 16-33% survival rate in plm80, plm100 and f-M groups at the same dose level (4mg/kg). The antitumor efficacy of plm60 was more encouraging in L1210 liver metastasis model. At a dose of 6mg/kg, approximately 90% animals receiving plm60 treatment could survive 60 days; however, in f-M group at the same dose, all the mice died at approximately 14 days post inoculation. Similarly, plm60 could effectively inhibit the growth of RM-1 tumor in BDF1 mice, resulting in marked increase in tumor doubling time at different dose levels relative to f-M. The improved antineoplastic effects could be ascribed to its small vesicle size, which allowed more drug release after the accumulation into tumor zone. Theoretical considerations revealed that the reduction of vesicle size could increase the specific area of MIT/sulfate precipitate inside the vesicle and the release constant K, which is inversely proportional to vesicle volume (K=pA(m)k(2)k(2)(')/([H(+)](i)(2)V(i))).

Copper ion-mediated liposomal encapsulation of mitoxantrone: the role of anions in drug loading, retention and release.

Besides pH gradient, other transmembrane gradients such as metal ion gradient could be also employed to load drugs into liposomes. In pH gradient method, anions have an important role since they could form specific aggregates with drugs, and then affect drug release kinetics from vesicles. To explore the role of anions in metal ion gradient method, copper ion-mediated mitoxantrone (MIT) loading was investigated systematically. When empty liposomes exhibiting a transmembrane copper ion gradient (300 mM) were mixed with MIT in a molar ratio of 0.2:1, after 5 min incubation at 60 degrees C, >95% MIT could be loaded into vesicles and the encapsulation was stable, regardless of the kinds of anions and initial intraliposomal pH values. The encapsulation ratio decreased with increased MIT/lipid molar ratio. But even when the molar ratio increased to 0.4, >90% encapsulation could still be achieved. In the presence of nigericin and ammonium, the drug loading profiles were affected to different degree with respect to both drug loading rate and encapsulation ratio. Relative to CuSO(4)-containing systems, CuCl(2) mediated MIT loading was unstable. Both nigericin and ammonium could alter the absorption spectra of liposomal MITs loaded with CuSO(4) gradient. In vitro release studies were performed in glucose/histidine buffer and in 50% human plasma using a dialysis method. In both of release media, CuCl(2)-containing vesicles displayed rapid release kinetics in comparison with CuSO(4) systems; and during the experiment period, MIT was lost from the vesicles continuously. When the formulations were injected into BDF1 mice at a dose of 4 mg/kg, all the liposomal formulations exhibited enhanced blood circulation time, with half-life values of 6.8-7.2h, significantly compared to the rapid clearance of free-MIT. In L1210 ascitic model, CuCl(2) formulation was more therapeutically active than CuSO(4) formulation. At a dose of 6 mg/kg, the treatment with CuCl(2) formulation resulted in a median survival time of 21 days, considerably larger than that of CuSO(4) groups (15 days). Based on these data, it was concluded that during the drug loading process, a dynamic transmembrane pH gradient is generated and intraliposomal pH might affect the complexation manner in which Cu(2+) binds MIT. Owing to the presence of pH gradient, after the accumulation within vesicles, a part of MIT will be protonated and precipitated by sulfate. Accordingly, the aggregation status of MIT inside CuSO(4) system was more complicated than that in CuCl(2) vesicles. The difference in physical status of MIT aggregates affects not only the drug release rate, but also their therapeutic effects.

Repeated injection of pegylated liposomal antitumour drugs induces the disappearance of the rapid distribution phase.

Upon repeated administration, empty pegylated liposomes lose their long-circulating characteristics, referred to as the accelerated blood clearance (ABC) phenomenon. To investigate whether cytotoxic drug-containing pegylated liposomes could also elicit a similar phenomenon, two pegylated liposomal antitumour drugs (doxorubicin and mitoxantrone) were prepared, and they were administrated twice in the same animals with a 10-day interval at a dose level of 8 mg kg(-1) (pegylated liposomal doxorubicin) and 4 mg kg(-1) (pegylated liposomal mitoxantrone). By comparing the overall pharmacokinetics after a single-dose injection with that in animals treated with two doses, it was surprising to find that repeated administration of pegylated liposomal antitumour drugs caused the disappearance of rapid distribution phase instead of the ABC phenomenon, resulting in the conversion of a two-compartment model to a one-compartment model. Further investigation revealed that repeated injection induced the decreased uptake of liposomal antitumour drugs by the spleen at the early time point of 0.5-8 h after injection. In contrast, the deposition of liposomal antitumour drugs into liver was not affected. Therefore, the disappearance of the rapid distribution phase might be related to the reduced spleen uptake at the early time point.

Efficient production of succinic acid from herbal extraction residue hydrolysate.

In this study, six different herbal-extraction residues were evaluated for succinic acid production in terms of chemical composition before and after dilute acid pretreatment (DAP) and sugar release performance. Chemical composition showed that pretreated residues of Glycyrrhiza uralensis Fisch (GUR) and Morus alba L. (MAR) had the highest cellulose content, 50% and 52%, respectively. Higher concentrations of free sugars (71.6 g/L total sugar) and higher hydrolysis yield (92%) were both obtained under 40 FPU/g DM at 10% solid loading for GUR. Using scanning electron microscopy (SEM), GUR was found to show a less compact structure due to process of extraction. Specifically, the fibers in pretreated GUR were coarse and disordered compared with that of GUR indicated by SEM. Finally, 65 g/L succinic acid was produced with a higher yield of 0.89 g/g total sugar or 0.49 g/g GUR. Our results illustrate the potential of GUR for succinic acid production.

Fluorinated polymeric micelles to overcome hypoxia and enhance photodynamic cancer therapy.

Photodynamic therapy (PDT) as an alternative choice of cancer treatment method has attracted increasing attention in the past few decades. A sufficient amount of oxygen is essential for the production of singlet oxygen (1O2) in successful PDT; however, hypoxia is a typical hallmark of cancer, which is one of the most important limitation factors of PDT. To overcome the hypoxic tumour microenvironment and achieve highly efficient photodynamic cancer therapy, herein, a photosensitizer Ce6-loaded fluorinated polymeric micelle (Ce6-PFOC-PEI-M) was constructed via the self-assembly of an amphiphilic polymer prepared from perfluorooctanoic acid and branched polyethyleneimine (10 kDa). The introduction of perfluoroalkyl groups in the polymeric micelle Ce6-PFOC-PEI-M retained the oxygen-carrying capacity similar to perfluorocarbon, increased the oxygen level and overcame the hypoxia in C6 glioma cells under oxygen-deficient conditions. As a control, Ce6-OC-PEI-M without a perfluoroalkyl group could not increase the oxygen level in C6 glioma cells under the same conditions. With laser irradiation, Ce6-PFOC-PEI-M generated much more reactive oxygen species (ROS) in C6 glioma cells than Ce6-OC-PEI-M, leading to a higher phototoxicity in vitro and photodynamic tumour growth inhibition in vivo than Ce6-OC-PEI-M. Furthermore, there were no differences in the contents of Ce6 in tumour tissue between Ce6-PFOC-PEI-M and Ce6-OC-PEI-M. The higher efficacy of Ce6-PFOC-PEI-M in PDT is ascribed to its oxygen-carrying ability rather than higher content of Ce6 in the tumour. The presented fluorinated polymeric micelle could provide a new platform in the delivery of various photosensitizers and has great potential to improve the efficacy of PDT cancer therapy.

Direct comparison of two pegylated liposomal doxorubicin formulations: is AUC predictive for toxicity and efficacy?

Rationally designed liposomes could improve the therapeutic indexes of chemotherapeutic drugs, which is due to alterations in the pharmacokinetics and biodistribution of encapsulated drugs. For traditional drug delivery systems, the accumulation of drugs in healthy and malignant tissues could be correlated with toxicity and efficacy. Some previous studies also indicate that the higher tumor AUC, the better therapeutic efficacy, suggestive of the possible existence of positive correlation. Are AUC values of liposomal drugs really predictive? For the purpose to address this question, we designed two pegylated liposomal doxorubicin formulations (PLD-75 and PLD-100), which had the same lipid/drug ratio and bilayer composition, but different size and internal ammonium sulfate concentration. In vitro drug retention experiments revealed that drug was released at a faster rate from PLD-75, a small size formulation. The plasma pharmacokinetics of PLD-75 was similar to that of PLD-100, regardless of whether the mice were tumor-free or not. It should be noted, though, that in tumor-bearing mice the plasma doxorubicin level in PLD-75 group was only about 59% of that in PLD-100 group at 48 h post injection. Furthermore, their biodistribution behavior in S-180 tumor-bearing KM mice was significantly different. Compared with animals receiving PLD-100, those receiving PLD-75 showed a 19.2%, 27.8%, and 23.5% decrease in liver (p<0.01), spleen (p<0.001) and lung (p<0.05) AUC, respectively. In other healthy tissues except kidney, the drug deposition also reduced by 10-15%, but the difference was not significant. The tumor AUC after administration of PLD-100 and PLD-75 were 1285.3 ugh/g and 762.0 ugh/g, respectively (p<0.001). Maximum drug levels achieved in the tumors were 33.80 microg/g (for PLD-100) and 20.85 microg/g (for PLD-75), and peak tumor concentration was achieved faster in PLD-75 group. However, enhanced drug accumulation does not mean increased antineoplastic effect, and at the same doxorubicin dose level, PLD-75 was more efficacious. As for toxicity studies, PLD-75 caused more rapid and severe body weight loss despite the fact that drug accumulation in healthy tissues was reduced. Our data indicate that liposomal systems are more complicated than conventional drug delivery systems, and it is hard to predict the toxicity and efficacy of liposomal drugs through the measure of liposomal drug accumulation.