Caproate Research Articles

Effect of electron acceptors on product selectivity and carbon flux in carbon chain elongation with Megasphaera hexanoica

Megasphaera hexanoica is a bacterial strain following the reverse β-oxidation pathway to synthesize caproate (CA) using lactate (LA) as an electron donor (ED) and acetate (AA) or butyrate (BA) as electron acceptors (EA). Differences in the type and concentration of EA lead to distinctions in product distribution and energy bifurcation of carbon fluxes in ED pathways, thereby affecting CA production. In this study, the effect of various ratios of AA, BA, and AA+BA as EA on carbon flux and CA specific titer during the carbon chain elongation in M. hexanoica was explored. The results indicated that the maximum levels of CA were 18.81 mM and 31.48 mM when the molar ratios of LA/AA and LA/BA were 10:1 and 3:1, respectively. Meanwhile, when AA and BA were used as combined EA (LA, AA, and BA molar amounts of 100, 23, and 77 mM), a maximum CA production of 39.45 mM was obtained. Further analysis revealed that the combined EA exhibited a CA production carbon flux of 49 % (4.3 % and 19.5 % higher compared to AA or BA, respectively) and a CA production specific titer of 45.24 mol (80.89 % and 58.51 % higher compared to AA or BA, respectively), indicating that the effective carbon utilization rate and CA production efficiency were greatly improved. Finally, a scaled-up experiment was conducted in a 1.2 L (working volume) automated bioreactor, implying high biomass (optical density at 600 nm or OD600 = 1.809) and a slight decrease in CA production (28.45 mM). A decrease in H2 production (4.11 g/m3) and an increase in CO2 production (0.632 g/m3) demonstrated the appropriate metabolic adaptation of M. hexanoica to environmental changes such as stirring shear.

Caproic acid production through lactate-based chain elongation: Effect of lactate-to-acetate ratio and substrate loading

Substrate properties play a key role in promoting the caproate yield through lactate-based carbon chain elongation pathway. In the present study, the effect of lactate-to-acetate (LA/AA) carbon ratio (from 0.5 to 5.0) and substrate loading (in terms of substrate/inoculum ratio within the range 20–180 mmol-C/g-VSS) on caproate fermentation was investigated. Results showed that both caproate content and yield increased by increasing the LA/AA ratio up to 3.0, then decreased at higher ratios due to activation of acrylate pathway and dispersion of carbon flux at elevated lactate content. At the optimal LA/AA carbon ratio of 3.0, substrate loading lower than 100 mmol-C/g-VSS was beneficial for efficient substrate utilization with low caproate selectivity, while higher substrate-to-inoculums (S/I) ratio led to incomplete substrate utilization and dispersed carbon flow, which finally reduced the caproate yield. Thus, the highest caproate yield of 0.42 g-COD/g-COD and selectivity of 49.5% were recorded at LA/AA and S/I ratio ratios of 3.0 and 100 mmol-C/g-VSS, respectively. The present study further depictures the novel approach for caproate production with lactate. • Different lactate-to-acetate (LA/AA) and substrate-to-inoculums (S/I) ratios were evaluated. • Highest caproate (CA) yield was found at LA/AA ratio of 3.0 and S/I ratio of 100 mmol-C/g-VSS. • LA/AA ratios over 3.0 activate acrylate pathway and reduce the CA production. • High S/I ratios reduce substrate utilization and disperse lactate carbon. • Butyrate was the dominant intermediate during lactate-based chain elongation.

Branded vs. Compounded Progesterone for Preventing Preterm Birth: Not Getting More for the Money

Weekly intramuscular injection of 17-alpha hydroxyprogesterone caproate (17-OHP) during pregnancy in women with prior histories of preterm birth has

Effect of 17α-hydroxyprogesterone caproate and medroxyprogesterone acetate on inflammation-induced preterm birth of mouse model

Objective To study the effect of 17α-hydroxyprogesterone caproate (17P) and medroxyprogesterone acetate (MPA) on expression of tumor necrosis factor-α (TNF-α)and cyclooxygenase-2 (COX-2) in placenta and uterine myometrium of inflammation-induced preterm birth mouse model to investigate the mechanism of preventing inflammation-induced preterm birth by progestogen.Methods Thirty clean CD-1 mice were divided into 6 groups (5 mice in each group) at 15th day of gestation:control group,lipopolysaccharides (LPS) group,17P 1 mg+LPS group,17P 2 mg+ LPS group,MPA 1 mg+LPS group and dimethyl sulfoxide (DMSO) + LPS group.Progestogens at different dosage were administered 1 h before LPS and 6 h after LPS administration.After these mice were sacrificed,TNF-α and COX-2 levels in the myometrium and placenta were detected by real-time PCR and immunohistochemistry.Data were analyzed by ANOVA,and comparisons between groups were adopted LSD method.Results 1.The comparison of relative expression of COX-2 mRNA and TNF-α mRNA in myometrium and placenta among groups:(1) Expressions of COX-2 mRNA and TNF-α mRNA in myometrium and placenta in the study groups were obviously higher than those of control group (P＜0.05).(2) COX-2 mRNA expression in myometrium of 17P 1 mg+LPS group (11.410±3.931),17P 2 mg+LPS group (8.352±3.209) and MPA 1 mg+LPS group (11.920± 2.905) were obviously lower than that of LPS group (20.540± 4.147) and DMSO+ LPS group (18.620 ± 4.156) (P＜0.05,respectively) ; although TNF-α mRNAexpression had similar trends among these groups,there were no statistical significance (P＞0.05,respectively).(3) COX-2 mRNA expression in placenta of 17P 1 mg+LPS group (10.864±3.777),17P 2 mg+LPS group (7.084±1.667) and MPA 1 mg+LPS group (11.830±3.652) were obviously lower than that of LPS group (18.920±4.106) and DMSO+LPS group (23.820±7.554)(P＜0.05,respectively).(4) TNF-α mRNA expression in placenta in 17P 1 mg+LPS group (14.340±1.618),17P 2 mg+ LPS group (11.488 ± 2.910) and MPA 1 mg+ LPS group (13.040 ± 2.982) were obviously lower than that of LPS group (24.240±7.059) and DMSO+LPS group (23.040±5.896) (P＜0.05,respectively).2.The comparison of protein expression of COX-2 and TNF-α in placenta among groups:(1) The expression of COX-2 protein in placenta of the study groups was significantly higher than that of control group (P＜0.05).(2) There were no differences among the COX-2 protein expression of 17P 1 mg+ LPS group (14 360.92± 1766.01),17P 2 mg+ LPS group (13 340.18±965.35) and MPA 1 mg+LPS group (12 870.81±1521.97)(P＞0.05),while the COX-2 protein expressions of them were significantly lower than that of LPS group (16 426.64 ± 1823.87) and DMSO+LPS group (16 761.23±2388.17)(P＜0.05,respectively).(3) There were no differences among the TNF-α protein expression of 17P 1 mg+LPS group (22 750.96±4656.68),17P 2 mg+LPS group (22766.24± 3500.34) and MPA 1 mg+LPS group (20770.01±3318.48)(P＞0.05),while the TNF-α protein expressions of them were significantly lower than that of LPS group (26204.49±5090.34) and DMSO+LPS group (27346.18±3269.30)(P＜0.05,respectively).Conclusions 17P and MPA might prevent the preterm parturition of inflammation-induced mouse model by inhibiting inflammation cytokines and prostaglandins. Key words: Premature birth; Hydroxyprogesterones; Medroxyprogesterone 17-acetate

Twin Gestations Remain Associated with Risk for Preterm Delivery

Weekly treatment with 17 alpha-hydroxyprogesterone caproate (17P) recently was shown to reduce the rate of recurrent preterm birth in singleton

Should Women at Risk for Preterm Birth Be Treated with 17P

About 12% of all U.S. births are preterm (<37 completed weeks of pregnancy). Randomized trials have shown that administering 17α-hydroxyprogesterone caproate (17P) reduces the risk for recurrent spontaneous preterm birth; in the largest trial, 17P reduced the rate of preterm deliveries …

Do Progesterone Injections Prevent Recurrent Preterm Birth

Results from some studies have suggested that 17 α-hydroxyprogesterone caproate (17P) reduces the incidence of preterm delivery. In this study, funded

Ion-pair partition of quarternary ammonium drugs: the influence of counter ions of different lipophilicity, size, and flexibility.

The ion-pair partition of quaternary ammonium (QA) pharmacons with organic counter ions of different lipophilicity, size, shape and flexibility was studied to elucidate relationships between ion-pair formation and chemical structure. The apparent partition coefficient (P') of 4 QAs was measured in octanol/pH 7.4 phosphate buffer system by the shake-flask method as a function of molar excess of ten counter ions (Y), namely: mesylate (MES), acetate (AC), pyruvate (PYRU), nicotinate (NIC), hydrogenfumarate (HFUM), hydrogenmaleate (HMAL), p-toluenesulfonate (PTS), caproate (CPR), deoxycholate (DOC) and prostaglandin E1 anion (PGE1). Based on 118 of highly precise logP' values (SD< 0.05), the intrinsic lipophilicity (without external counter ions) and the ion-pair partition of QAs (with different counter ions) were characterized. Linear correlation was found between the logP' of ion-pairs and the size of the counter ions described by the solvent accessible surface area (SASA). The lipophilicity increasing effect of the counter ions were quantified and the following order was established: DOC approximate to PGE1 >> CPR approximate to PTS >> NIC approximate to HMAL >> PYRU approximate to AC approximate to MES approximate to HFUM. Analyzing the lipophilicity/molar ratio (QA:Y) profile, the differences in the ion-pair formation were shown and attributed to the differences in the flexibility/rigidity and size both of QA and Y. Since the largest (in average, 300 X) lipophilicity enhancement was found by the influence of DOC and PGE1 and considerable (on average 40 X) increase was observed by CPR and PTS, it was concluded that bile acids and prostaglandin anions may play a significant role in the ion-pair transport of quaternary ammonium drugs and caproic acid and p-toluenesulfonic acid may be useful salt forming agents to improve the pharmacokinetics of hydrophilic drugs.