Engineered Corynebacterium glutamicum as an endotoxin-free platform strain for lactate-based polyester production

The first biosynthetic system for lactate (LA)-based polyesters was previously created in recombinant Escherichia coli (Taguchi et al. 2008). Here, we have begun efforts to upgrade the prototype polymer production system to a practical stage by using metabolically engineered Gram-positive bacterium Corynebacterium glutamicum as an endotoxin-free platform. We designed metabolic pathways in C. glutamicum to generate monomer substrates, lactyl-CoA (LA-CoA), and 3-hydroxybutyryl-CoA (3HB-CoA), for the copolymerization catalyzed by the LA-polymerizing enzyme (LPE). LA-CoA was synthesized by D-lactate dehydrogenase and propionyl-CoA transferase, while 3HB-CoA was supplied by β-ketothiolase (PhaA) and NADPH-dependent acetoacetyl-CoA reductase (PhaB). The functional expression of these enzymes led to a production of P(LA-co-3HB) with high LA fractions (96.8 mol%). The omission of PhaA and PhaB from this pathway led to a further increase in LA fraction up to 99.3 mol%. The newly engineered C. glutamicum potentially serves as a food-grade and biomedically applicable platform for the production of poly(lactic acid)-like polyester

Anti-tumor effects of a nonsteroidal anti-inflammatory drug zaltoprofen on chondrosarcoma via activating peroxisome proliferator-activated receptor gamma and suppressing matrix metalloproteinase-2 expression.

金沢大学医薬保健研究域医学系Surgical resection is the only treatment for chondrosarcomas, because of their resistance to chemotherapy and radiotherapy; therefore, additional strategies are crucial to treat chondrosarcomas. Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor, which has been reported as a possible therapeutic target in certain malignancies including chondrosarcomas. In this study, we demonstrated that a nonsteroidal anti-inflammatory drug, zaltoprofen, could induce PPARγ activation and elicit anti-tumor effects in chondrosarcoma cells. Zaltoprofen was found to induce expressions of PPARγ mRNA and protein in human chondrosarcoma SW1353 and OUMS27 cells, and induce PPARγ-responsible promoter reporter activities. Inhibitory effects of zaltoprofen were observed on cell viability, proliferation, migration, and invasion, and the activity of matrix metalloproteinase-2 (MMP2); these effects were dependent on PPARγ activation and evidenced by silencing PPARγ. Moreover, we showed a case of a patient with cervical chondrosarcoma (grade 2), who was treated with zaltoprofen and has been free from disease progression for more than 2 years. Histopathological findings revealed enhanced expression of PPARγ and reduced expression of MMP2 after administration of zaltoprofen. These findings demonstrate that zaltoprofen could be a promising drug against the malignant phenotypes in chondrosarcomas via activation of PPARγ and inhibition of MMP2 activity. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.2957320

コミュニティーを基礎としたマイクロ・インシュランス(CBHI)の購入決定因と健康への影響--カンボジア農村の事例より--

発展途上国における貧困家計の所得平準化を目的として、CBHIの導入が図られているが、購入者の割合は依然として低い。本論文は、カンボジアにおけるCBHI購入を規定する要因と、保険を購入し利用することによる健康への影響を検証することを目的とする。そのため、カンボジア農村において収集した家計データを用い、リスクや時間選好を考慮して、選択モデルによる購入決定因の分析と、保険を購入し利用することが家計員の健康状態におよぼす影響について単純な回帰分析の手法を用いて分析した。分析の結果は、CBHIの購入と利用が家計員の健康に負の影響をおよぼすこと、過去における疾病経験、高齢者の割合が保険購入に有意な正の影響をおぼすこと、および、時間割引率が低いほど保険を購入する傾向があることを示している

Establishment of a metabolic pathway to introduce the 3-hydroxyhexanoate unit into LA-based polyesters via a reverse reaction of β-oxidation in Escherichia coli LS5218

New lactate (LA)-based terpolymers, P[LA-co-3-hydroxybutyrate (3HB)-co-3-hydroxyhexananoate (3HHx)]s, were produced in recombinant Escherichia coli LS5218 harboring three genes encoding LA-polymerizing enzyme (LPE), propionyl-coenzyme A (CoA) transferase (PCT) and (R)-specific enoyl-CoA hydratase (PhaJ4). When the recombinant LS5218 was grown on glucose with the feeding of butyrate, 3HB-CoA and 3HHx-CoA were supplied, probably via reverse reactions of the β-oxidation pathway and PhaJ4. LPE copolymerized the two monomers with LA-CoA, which was generated by PCT, to yield the terpolymers. Gas chromatography analysis revealed that the terpolymers consisted of 2.7 to 34 mol% LA, 38 to 81 mol% 3HB and 17 to 33 mol% 3HHx units, which can be varied depending on the butyrate concentration fed in the medium. In addition, 1H-13C COSY NMR analysis provided evidence for a linkage between LA and 3HHx units in the polymer

Lactate fraction dependent mechanical properties of semitransparent poly(lactate-co-3-hydroxybutyrate)s produced by control of lactyl-CoA monomer fluxes in recombinant Escherichia coli

In order to evaluate the mechanical properties of poly(lactate-co-3-hydroxybutyrate) [P(LA-co-3HB)] and its correlation with the LA fraction, P(LA-co-3HB)s with a variety of LA fractions were prepared using recombinant Escherichia coli expressing the LA-polymerizing enzyme and monomer supplying enzymes. The LA-overproducing mutant E. coli JW0885 with a pflA gene disruption was used for the LA-enriched polymer production. The LA fraction was also varied by jar-fermentor based fine-regulation of the anaerobic status of the culture conditions, resulting in LA fractions ranging from 4 to 47 mol%. In contrary to the opaque P(3HB) film, the copolymer films attained semitransparency depending on the LA fraction. Young's modulus values of the P(LA-co-3HB)s (from 148 to 905 MPa) were lower than those of poly(lactic acid) (PLA) (1020 MPa) and P(3HB) (1079 MPa). In addition, the values of elongation at break of the copolymer with 29 mol% LA reached 150%. In conclusion, P(LA-co-3HB)s were found to be a comparatively pliable and flexible material, differing from both of the rigid homopolymers

Does Child Labour Have a Negative Impact on Child Education and Health? A Case Study in Rural Cambodia

This paper examines whether child labour affects the acquisition of a child's human capital. For this purpose, a behavioural model in which child labour is itself a choice and simultaneous equation models with limited dependent variables are employed to examine the determinants of human capital formation and its relationship with child labour. No trade-off relationship could be found between child labour and child schooling attainment. However, it was found that child labour is not detrimental to a child's health and nutritional status; rather, it improves these if children work within a critical threshold level.

小口医療保険の潜在的需要者による属性評価の離散選択モデル分析 --カンボジア農村の事例

途上国における貧困緩和政策の一環として、貧困層向け小口医療保険の普及が試みられているが、参加率は依然として低いままである。本稿は、カンボジア農村における貧困層向け小口医療保険制度へ参加を促進するためには、どのように現行保険制度を改善すればいいのかを考察しようとしたものである。そのために、本稿では、農村住民を対象にした選択的実験を行うことにより収集したデータをコンジョイント法により分析し、設定した保険属性(保険料水準、診療を担当する医療機関の種類、医療サービスの水準、保険運営機関によるマネージメントの水準)の水準ごとの支払い意思額を推計した。分析の結果は、民間クリニックでの診療、歯科・眼科の外科的治療、慢性的疾病の長期的治療、国立病院での診療に対する需要が高いことが明らかになった。これらの分析結果は、小口医療保険に対する潜在的需要は高く、スキーム改善の方向次第では参加率が高まる可能性があることを示唆している。ただし、国立病院での診療を除くと、行政費用や医療技術上の問題があり、現実的な処方箋であるかに関してはさらなる研究が必要である