Aeromonas hydrophila WQ isolated from lake water was found to be able to synthesize polyhydroxyalkanoates (PHA) copolymer consisting of 3-hydroxybutyrate (HB) and 3-hydroxyhexanoate (HHx) (PHBHHx). Lauric acid was fou...Aeromonas hydrophila WQ isolated from lake water was found to be able to synthesize polyhydroxyalkanoates (PHA) copolymer consisting of 3-hydroxybutyrate (HB) and 3-hydroxyhexanoate (HHx) (PHBHHx). Lauric acid was found to be the most suitable carbon source for cell growth and PHBHHx accumulation. The bacteria accumulated 49% PHBHHx containing 6% HHx in terms of cell dry weight when grown on lauric acid for 72 h. 42% PHBHHx consisting of 14% HHx was obtained with 5 g/L glucose and 10 g/L lauric acid as co-substrate. Higher glucose concentration greatly reduced the cell concentration and PHA content. The PHA biosynthesis genes from A. hydrophila WQ was successfully cloned using a two-step PCR cloning strategy based on PHA biosynthesis genes organization of Aeromonas caviae. A. hydrophila WQ and A.caviae shared high identities in the PHA gene loci, namely, ORF1, phaC and phaJ had 100%, 97% and 97.5% identities respectively. PHA synthases of A. caviae and A. hydrophila were proposed to contain type IV PHA synthases which are different compared with type I PHA synthases on the substrate specificity and location arrangement of PHA metabolic genes.展开更多
Sustained release and non-parental formulations of peptides and protein drugs are highly desirable because of enhanced therapeutic effects as well as improved patient compliance. This is especially true for small pept...Sustained release and non-parental formulations of peptides and protein drugs are highly desirable because of enhanced therapeutic effects as well as improved patient compliance. This is especially true for small peptides such as thymopentin(TP5). To this end, implantable sandwich poly(hydroxybutyrate-co-hydroxyhexanoate)(PHBHHx) films were designed to prolong release time and to inhibit burst release phenomenon of TP5 by a simple volatilization method. In vitro release studies revealed that sandwich films had nearly no burst release. In vivo release time of sandwich films was prolonged to 42 days. Pharmacodynamic evaluation demonstrated that TP5 sandwich films significantly increased survival rates in a rat immunosuppressive model and normalized CD4^+/CD8^+ values. These results suggest that TP5 released from sandwich films can attenuate cyclophosphamide's immunosuppressive activity, and possibly achieve results comparable to daily TP5 injection therapy. Thus, sandwich PHBHHx films show excellent potential as a sustained, burst-free release system for small molecular weight, hydrophilic peptide drugs.展开更多
Biodegradable polymeric nanoparticles are more and more frequently used in drug delivery systems, which represent one of the most rapidly developing areas.Inourpreviousstudy,a novelnaturalhybrid polyester,polyethylene...Biodegradable polymeric nanoparticles are more and more frequently used in drug delivery systems, which represent one of the most rapidly developing areas.Inourpreviousstudy,a novelnaturalhybrid polyester,polyethylene glycol 200 (PEG200) end-capped poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx-PEG) was directly produced by Aeromonas hydrophila fermentation. In this study, the performance of the novel biodegradable PHBHHx-PEG copolyester as a sustained release carrier for hydrophobic drugs with different molecular weights and the in vitro sustained release profile were investigated. 5-Fluorouracil(5-Fu, Mw=130.1), TGX221(Mw=364.4), and Rapamycin(RAP, Mw=914.2) were used as the model drugs. PHBHHx-PEG nanoparticles entrapped with 5-Fu, TGX221 and RAP were fabricated by a modified emulsification/solvent evaporation method, respectively. The average diameter of 5-Fu,TGX221, and RAP loaded PHBHHx-PEG nanoparticles was between 198.2-217.4 nm,and the entrapment efficiency of the three drugs was 62.5%, 93.4% and 91.9%,respectively. The in vitro release profiles of 5-Fu, TGX221 and RAP from PHBHHx-PEG nanoparticles were different. 5-Fu showed faster release rate and an obvious initial burst release phase. TGX221 and RAP were demonstrated to be released more slowly and steadily. The release percentages of 5-Fu, TGX221 and RAP were97.7%, 85.1% and 74.7% after releasing for 72 h. PHBHHx-PEG is a kind of promising material as a carrier for the entrapment and delivery of hydrophobic drugs especially for those drugs with high molecular weight.展开更多
文摘Aeromonas hydrophila WQ isolated from lake water was found to be able to synthesize polyhydroxyalkanoates (PHA) copolymer consisting of 3-hydroxybutyrate (HB) and 3-hydroxyhexanoate (HHx) (PHBHHx). Lauric acid was found to be the most suitable carbon source for cell growth and PHBHHx accumulation. The bacteria accumulated 49% PHBHHx containing 6% HHx in terms of cell dry weight when grown on lauric acid for 72 h. 42% PHBHHx consisting of 14% HHx was obtained with 5 g/L glucose and 10 g/L lauric acid as co-substrate. Higher glucose concentration greatly reduced the cell concentration and PHA content. The PHA biosynthesis genes from A. hydrophila WQ was successfully cloned using a two-step PCR cloning strategy based on PHA biosynthesis genes organization of Aeromonas caviae. A. hydrophila WQ and A.caviae shared high identities in the PHA gene loci, namely, ORF1, phaC and phaJ had 100%, 97% and 97.5% identities respectively. PHA synthases of A. caviae and A. hydrophila were proposed to contain type IV PHA synthases which are different compared with type I PHA synthases on the substrate specificity and location arrangement of PHA metabolic genes.
基金supported by the National Natural Science Foundation of China(No.81673362)
文摘Sustained release and non-parental formulations of peptides and protein drugs are highly desirable because of enhanced therapeutic effects as well as improved patient compliance. This is especially true for small peptides such as thymopentin(TP5). To this end, implantable sandwich poly(hydroxybutyrate-co-hydroxyhexanoate)(PHBHHx) films were designed to prolong release time and to inhibit burst release phenomenon of TP5 by a simple volatilization method. In vitro release studies revealed that sandwich films had nearly no burst release. In vivo release time of sandwich films was prolonged to 42 days. Pharmacodynamic evaluation demonstrated that TP5 sandwich films significantly increased survival rates in a rat immunosuppressive model and normalized CD4^+/CD8^+ values. These results suggest that TP5 released from sandwich films can attenuate cyclophosphamide's immunosuppressive activity, and possibly achieve results comparable to daily TP5 injection therapy. Thus, sandwich PHBHHx films show excellent potential as a sustained, burst-free release system for small molecular weight, hydrophilic peptide drugs.
基金National Natural Science Foundation of Chinagrant number:81172170,81371288+1 种基金Science and Technology Research and Development Program of Shanxi Provincegrant number:2013KW32-04
文摘Biodegradable polymeric nanoparticles are more and more frequently used in drug delivery systems, which represent one of the most rapidly developing areas.Inourpreviousstudy,a novelnaturalhybrid polyester,polyethylene glycol 200 (PEG200) end-capped poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx-PEG) was directly produced by Aeromonas hydrophila fermentation. In this study, the performance of the novel biodegradable PHBHHx-PEG copolyester as a sustained release carrier for hydrophobic drugs with different molecular weights and the in vitro sustained release profile were investigated. 5-Fluorouracil(5-Fu, Mw=130.1), TGX221(Mw=364.4), and Rapamycin(RAP, Mw=914.2) were used as the model drugs. PHBHHx-PEG nanoparticles entrapped with 5-Fu, TGX221 and RAP were fabricated by a modified emulsification/solvent evaporation method, respectively. The average diameter of 5-Fu,TGX221, and RAP loaded PHBHHx-PEG nanoparticles was between 198.2-217.4 nm,and the entrapment efficiency of the three drugs was 62.5%, 93.4% and 91.9%,respectively. The in vitro release profiles of 5-Fu, TGX221 and RAP from PHBHHx-PEG nanoparticles were different. 5-Fu showed faster release rate and an obvious initial burst release phase. TGX221 and RAP were demonstrated to be released more slowly and steadily. The release percentages of 5-Fu, TGX221 and RAP were97.7%, 85.1% and 74.7% after releasing for 72 h. PHBHHx-PEG is a kind of promising material as a carrier for the entrapment and delivery of hydrophobic drugs especially for those drugs with high molecular weight.
