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
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.
