An examination of the carbon metabolic pathways in Acinetobacter sp. TAC-1 in the context of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) utilization / 生物工程学报

The present study aimed to unravel the carbon metabolism pathway of Acinetobacter sp. TAC-1, a heterotrophic nitrification-aerobic denitrification (HN-AD) strain that utilizes poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) as a carbon source. Sodium acetate was employed as a control to assess the gene expression of carbon metabolic pathways in the TAC-1 strain. The results of genome sequencing demonstrated that the TAC-1 strain possessed various genes encoding carbon metabolic enzymes, such as gltA, icd, sucAB, acs, and pckA. KEGG pathway database analysis further verified the presence of carbon metabolism pathways, including the glycolytic pathway (EMP), pentose phosphate pathway (PPP), glyoxylate cycle (GAC), and tricarboxylic acid (TCA) cycle in the TAC-1 strain. The differential expression of metabolites derived from distinct carbon sources provided further evidence that the carbon metabolism pathway of TAC-1 utilizing PHBV follows the sequential process of PHBV (via the PPP pathway)→gluconate (via the EMP pathway)→acetyl-CoA (entering the TCA cycle)→CO2+H2O (generating electron donors and releasing energy). This study is expected to furnish a theoretical foundation for the advancement and implementation of novel denitrification processes based on HN-AD and solid carbon sources.

Biocompatibility between SGBG/PHBV and Human PDLC / 中山大学学报(医学科学版)

[Objective] The biocompatibility between SGBG/PHBV and human PDLC were investigated to provide a basis for the choice of the scaff material of periodontal tissue engineering.[Methods] Human PDLC were cultured using tissue-explant technique.Seeding on 96 wells plate,9 wells for one group,Four different concentrations (100％,75％,50％,25％,0％) of maceration extract of SGBG/PHBV were added into the culture plantsafter 48-h cell seeding,the grades of the cytotoxicity of SGBG/PHBV was evaluated by MTT assay.Human PDLC cultured in vitro were collected and seeded on the three-dimensional scaffolds of SGBG/PH-BV,the cellular morphology and cell growth on the scaffolds were observed and photographed by scanning electronic microscope.HumanPDLC seeded on the three-dimensional scaffolds of SGBG/PHBV in the experimental group,and human PDLC seeded by DMEM in the control group,after 12-,24-,and 48-h cell seeding,got 27 simples for each group,and the affection of the SGBG/PHBV on cell secretory function was observed by spectrophotometry which assayed the biochemical indexes ALP in supinate.[Results] The grades of the cytotoxicity of SGBG/PHBV were 0 and 1.It was displayed that human PDLC adhered and proliferated well on the scaffold of SGBG/PHBV under the scanning electronic microscope.The significant difference of ALP in supinate between the experimental group and the control group (P ＜ 0.05).[Conclusions] SGBG/PHBV had no cytotoxicity to human PDLC.SGBG/PHBV is potential to further study as the scaffolds of periodontal tissue engineering since it displayed the satisfactory biocompatibility with human PDLC.

Characterization of progesterone loaded biodegradable blend polymeric nanoparticles / Caracterização de nanopartículas blenda poliméricas biodegradáveis contendo progesterona

ABSTRACT:The encapsulation of progesterone in poly (hydroxybutirate-co-hydroxyvalerate) (PHBV), poly (ε-caprolactone) (PCL), poly (L-lactic acid) (PLLA) nanoparticles and PHBV/PCL and PHBV/PLLA blend nanoparticles was investigated in this research. Nanoparticles were produced by miniemulsion/solvent evaporation technique with lecithin as surfactant and were characterized regarding to z-average diameter (Dz) and polydispersity (PDI), progesterone recovery yield and encapsulation efficiency. Possible interactions between progesterone and the polymer matrices were investigated by Fourier Transform Infrared Spectroscopy (FTIR). High recoveries (up to 102.43±1.80% for the PHBV/PLLA blend) and encapsulation efficiencies (up to 99.53±0.04% for PCL) were achieved and the nanoparticles presented narrow size distribution (0.12±0.03 for PLLA). PCL nanoparticles (217.5±2.12nm) presented significant difference with the Dz from all the other formulations (P<0.05). The most evident interaction between progesterone and the nanoparticles polymeric matrix was found to PHBV/PCL due to the increase in the intensity of the band located in 1631 cm-1.

RESUMO:A encapsulação de progesterona em nanopartículas de poli(hidroxibutirato-co-hidroxivalerato) (PHBV), poli (ε-caprolactona) (PCL), poli (L-ácido lático) (PLLA) e em nanopartículas blenda de PHBV/PCL e PHBV/PLLA foi investigada neste trabalho. As nanopartículas foram produzidas pela técnica de miniemulsificação/evaporação do solvente com lecitina como surfactante e foram caracterizadas em relação ao diâmetro médio em intensidade (Dz) e o índice de polidispersão (PDI), rendimento de recuperação e eficiência de encapsulação de progesterona. Possíveis interações entre progesterona e as matrizes poliméricas foram investigadas por Espectroscopia de Infravermelho por Transformada de Fourier (FTIR). Valores elevados de rendimento de recuperação (de até 102,43±1,80% para a blenda PHBV/PLLA) e eficiência de encapsulação (de até 99,53±0,04% para PCL) foram obtidos e as nanopartículas apresentaram distribuição de tamanho estreita (0,12±0,03 para PLLA). As nanopartículas de PCL (217,5±2,12nm) apresentaram diferença significativa com todas as outras formulações (P<0,05) quanto ao Dz. A interação mais evidente entre progesterona e a matriz polimérica das nanopartículas foi para a blenda PHBV / PCL, devido ao aumento na intensidade da banda localizada em 1631 cm-1.

Superparamagnetic Poly (3-hydroxybutyrate-co-3 hydroxyvalerate) (PHBV) nanoparticles for biomedical applications

Background: The progress in material science and the recent advances in biodegradable/biocompatible polymers and magnetic iron oxide nanoparticles have led to develop innovative diagnostic and therapeutic strategies for diseases based on multifunctional nanoparticles, which include contrast medium for magnetic resonance imaging, agent for hyperthermia and nanocarriers for targeted drug delivery. The aim of this work is to synthesize and characterize superparamagnetic iron oxide (magnetite), and to encapsulate them into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles for biomedical applications. Results: The magnetite nanoparticles were confirmed by X-ray diffraction and exhibited a size of 22.3 ± 8.8 nm measured by transmission electron microscopy (TEM). Polymeric PHBV nanoparticles loaded with magnetite (MgNPs) were analyzed using dynamic light scattering and showed a size of 258.6 ± 35.7 nm and a negative zeta potential (-10.8 ± 3.5 mV). The TEM examination of MgNPs exhibited a spherical core-shell structure and the magnetic measurements showed in both, non-encapsulated magnetite and MgNPs, a superparamagnetic performance. Finally, the in vitro studies about the magnetic retention of MgNPs in a segment of small intestine of rats showed an active accumulation in the region of the magnetic field. Conclusions: The results obtained make the MgNPs suitable as potential magnetic resonance imaging contrast agents, also promoting hyperthermia and even as potential nanocarriers for site-specific transport and delivery of drugs.

Ceftiofur-loaded PHBV microparticles: a potential formulation for a long-acting antibiotic to treat animal infections

Background: The infectious diseases in the livestock breeding industry represent a significant drawback that generates substantial economic loss and have led to the indiscriminate use of antibiotics. The formulation of polymeric microparticles loaded with antibiotics for veterinary use can: reduce the number of required doses; protect the drug from inactivation; and maintain a sustained-release of the antibiotic drug at effective levels. Accomplishing all of these goals would have a significant economic and animal health impact on the livestock breeding industry. Results: In this work, we formulated ceftiofur-loaded PHBV microparticles (PHBV-CEF) with a spherical shape, a smooth surface and diameter sizes between 1.65 and 2.37 μm. The encapsulation efficiency was 39.5 +/- 1.1 percent w/w, and we obtained a sustained release of ceftiofur in PBS-buffer (pH 7.4) over 7 days. The antibacterial activity of ceftiofur was preserved after the encapsulation procedure, and toxicity of PHBV-CEF microparticles evaluated by MTS was represented by an IC50 > 10 mg/mL. Conclusions: Our results suggest that PHBV-CEF particles have a potential application for improving the treatment of infectious diseases in the livestock breeding industry.

Macroporous PHBV matrices for cartilage tissue engineering / 中国矫形外科杂志

[Objective]To investigate the possibility of using poly(hydroxybutyrate-co-hydroxyvalerate)(PHBV)as scaffolds for cartilage tissue engineering and to compare the engineered cartilage generated in vitro with those in nude mice modles.[Method]PHBV porous scaffolds were fabricated using a compression moulding,thermal processing and salt particulate leaching methods.Chondrocytes isolated from articular cartilage were seeded into porous PHBV scaffolds.After incubation for 2 weeks in vitro,chondrocytes-PHBV constructs were implanted subcutaneously in the dorsum of athymic nude mice.Control groups were established by subcutaneous implantation of PHBV alone.The implants harvested after in vivo incubation of 4 and 8 weeks and cell-scaffolds cultured in vitro for 6 and 10 weeks were respectively examined histologically.Chondrocytes cultured for 3,7 and 14 days on the scaffolds were examined by SEM.[Result]SEM showed that chondrocytes could aggregate and synthesize extracellular matrix on PHBV scaffolds.Both specimens harvested from nude mice and those cultured in vitro demonstrated new cartilage formation,while characteristics of the engineered cartilage generated in vivo were more typical.Those from control groups showed no cartilage formation.[Conclusion]PHBV can be used as scaffolds for cartilage tissue engineering and nude mice modle seems to facilitate chondrogenesis compared with that in vitro system.