Combination of a Push-Pull-Block Strategy with a Heterologous Xylose Assimilation Pathway toward Lipid Overproduction from Lignocellulose in Yarrowia lipolytica.

The production of biodiesel using microbial lipids derived from renewable lignocellulosic biomass is considered a promising strategy to reduce environmental pressure and promote the green energy transition. The hydrolysates of lignocellulosic biomass are rich in glucose and xylose, which makes it crucial to efficiently utilize both sugars. Here, we combined metabolic engineering and adaptive laboratory evolution (ALE) to construct an engineered Yarrowia lipolytica strain that can efficiently produce lipids from glucose and xylose. First, the "Push-Pull-Block" strategy was adopted to increase lipid content to 73.42% of the dry cell weight (DCW). Then, a heterologous xylose-utilization pathway was integrated into the engineered strain, which was subjected to ALE. The final evolved strain could accumulate 53.64% DCW of lipids from xylose, and the lipid titer reached 16.25 g/L. This work sheds light on the potential of microbial lipid overproduction from lignocellulose using engineered Y. lipolytica.

Metabolic and Process Engineering for Producing the Peach-Like Aroma Compound γ-Decalactone in Yarrowia lipolytica.

Due to its strong and unique peach-like aroma, γ-decalactone is widely used in dairy products and other foods or beverages. The oleaginous yeast Yarrowia lipolytica, which is generally regarded as safe, has shown great potential in the production of this flavor compound. Recently, the development of metabolic and process engineering has enabled the application of Y. lipolytica for the production of γ-decalactone. This Review summarizes the relevant biosynthesis and degradation pathways of Y. lipolytica, after which the related metabolic engineering strategies to increase the accumulation of γ-decalactone are summarized. In addition, the factors affecting γ-decalactone accumulation in Y. lipolytica are introduced, and corresponding process optimization strategies are discussed. Finally, the current research needs are analyzed to search for remaining challenges and future directions in this field.

Engineering Yarrowia lipolytica to produce fuels and chemicals from xylose: A review.

The production of chemicals and fuels from lignocellulosic biomass has great potential industrial applications due to its economic feasibility and environmental attractiveness. However, the utilized microorganisms must be able to use all the sugars present in lignocellulosic hydrolysates, especially xylose, the second most plentiful monosaccharide on earth. Yarrowia lipolytica is a good candidate for producing various valuable products from biomass, but this yeast is unable to catabolize xylose efficiently. The development of metabolic engineering facilitated the application of Y. lipolytica as a platform for the bioconversion of xylose into various value-added products. Here, we reviewed the research progress on natural xylose-utilization pathways and their reconstruction in Y. lipolytica. The progress and emerging trends in metabolic engineering of Y. lipolytica for producing chemicals and fuels are further introduced. Finally, challenges and future perspectives of using lignocellulosic hydrolysate as substrate for Y. lipolytica are discussed.

Effect of stellate ganglion block on hemodynamics and stress responses during CO2-pneumoperitoneum in elderly patients.

STUDY OBJECTIVE: Elderly patients undergoing elective laparoscopic cholecystectomy (LC) were given right stellate ganglion block (RSGB) to observe its effects on the hemodynamics and stress response during carbon dioxide (CO2)-pneumoperitoneum. DESIGN: A randomized, single-blinded, and placebo-controlled study. SETTING: University-affiliated teaching hospital. PARTICIPANTS: Sixty patients (aged 65-78years; weight, 45-75kg; American Society of Anesthesiologists (ASA) physical status classification, class I or II) undergoing elective LC. INTERVENTIONS: Right stellate ganglion block was performed via C7 access using 10mL of 1% lidocaine in all patients. MEASUREMENTS: The patients' heart rate (HR) and mean arterial pressure (MAP) were recorded before the block (T0), 5min following pneumoperitoneum (T1), 30min following pneumoperitoneum (T2), 5min following the deflation of pneumoperitoneum (T3), and upon completion of the surgery (T4). Additionally, the concentrations of epinephrine (E), norepinephrine (NE) and cortisol (COR) were detected in arterial blood at each time point by enzyme-linked immunosorbent assay. MAIN RESULTS: For control group, the MAP and RPP (RPP=SBP×HR) were significantly elevated at T1~3 (P<0.05) as compared to T0. Inter-group comparison showed that the MAP, HR and RPP were significantly lower at T1~4 in RSGB group (P<0.05 or 0.01). As compared to T0, the E, NE and COR levels significantly rose at T1~4 in control group (P<0.05 or 0.01) and COR at T2, 3 in RSGB group (P<0.05). The E, NE and COR levels at T1~4 were significantly lower in RSGB group as compared to control group (P<0.05 or 0.01). CONCLUSION: Right stellate ganglion block can reduce blood catecholamines during CO2-pneumoperitoneum to maintain perioperative hemodynamic stability and prevent adverse cardiovascular events in elderly patients.

Solution structure of the ubiquitin-like domain of human DC-UbP from dendritic cells.

The previously identified dendritic cell-derived ubiquitin-like protein (DC-UbP) was implicated in cellular differentiation and apoptosis. Sequence alignment suggested that it contains a ubiquitin-like (UbL) domain in the C terminus. Here, we present the solution NMR structure and backbone dynamics of the UbL domain of DC-UbP. The overall structure of the domain is very similar to that of Ub despite low similarity (<30%) in amino-acid sequence. One distinct feature of the domain structure is its highly positively charged surface that is different from the corresponding surfaces of the well-known UbL modifiers, Ub, NEDD8, and SUMO-1. The key amino-acid residues responsible for guiding polyubiquitinated proteins to proteasome degradation in Ub are not conserved in the UbL domain. This implies that the UbL domain of DC-UbP may have its own specific interaction partners with other yet unknown cellular functions related to the Ub pathway.