Machine-Learning-Guided Engineering of an NADH-Dependent 7ß-Hydroxysteroid Dehydrogenase for Economic Synthesis of Ursodeoxycholic Acid.

Enzymatic synthesis of ursodeoxycholic acid (UDCA) catalyzed by an NADH-dependent 7ß-hydroxysteroid dehydrogenase (7ß-HSDH) is more economic compared with an NADPH-dependent 7ß-HSDH when considering the much higher cost of NADP+/NADPH than that of NAD+/NADH. However, the poor catalytic performance of NADH-dependent 7ß-HSDH significantly limits its practical applications. Herein, machine-learning-guided protein engineering was performed on an NADH-dependent Rt7ß-HSDHM0 from Ruminococcus torques. We combined random forest, Gaussian Naïve Bayes classifier, and Gaussian process regression with limited experimental data, resulting in the best variant Rt7ß-HSDHM3 (R40I/R41K/F94Y/S196A/Y253F) with improvements in specific activity and half-life (40 °C) by 4.1-fold and 8.3-fold, respectively. The preparative biotransformation using a "two stage in one pot" sequential process coupled with Rt7ß-HSDHM3 exhibited a space-time yield (STY) of 192 g L-1 d-1, which is so far the highest productivity for the biosynthesis of UDCA from chenodeoxycholic acid (CDCA) with NAD+ as a cofactor. More importantly, the cost of raw materials for the enzymatic production of UDCA employing Rt7ß-HSDHM3 decreased by 22% in contrast to that of Rt7ß-HSDHM0, indicating the tremendous potential of the variant Rt7ß-HSDHM3 for more efficient and economic production of UDCA.

A 3D tetrathiafulvalene-based metal-organic framework with intramolecular charge transfer for efficient near-infrared photothermal conversion.

The selection of metal centers can endow donor-metal-accepter (D-M-A) type MOFs with progressive framework dimensions. 3D Cd-based MOFs with intramolecular charge transfer caused by D-M-A exhibit a satisfactory photothermal conversion efficiency of 35.7%, with the temperature rapidly rising from 25 °C to 201 °C in 7 s under 808 nm laser irradiation.

Functional and emulsification characteristics of phospholipids and derived o/w emulsions from peony seed meal.

Peony seed phospholipids (PPLs), a kind of multifunctional plant-like phospholipids were extracted from peony seed meal. We investigated the functional properties of PPLs and compared their emulsification performance in corn oil-peony seed oil o/w emulsion systems with that of soy lecithin (DPLs). The PPLs were characterized with the higher content of phosphatidylcholine (PC) (416 ± 28 mg/g) and lyso-phosphatidylcholine (LPC) (43 ± 14 mg/g) fractions, and lower content of phosphatidylethanolamine (PE) (71 ± 13 mg/g). The polyunsaturated fatty acids showed higher content (83.25%), with the highest content of linoleic acid (46.05%) in PPLs. PPLs-emulsions showed smaller average particle size and higher loaded peony seed oil content at pH 5, temperature 50 °C, and about 60% corn oil content. PPLs-emulsions imparted better hydroxyl radical scavenging efficiency and reducing power than DPLs. Our results suggest that PPLs can be used as emulsifiers with improved antioxidant properties.

Simultaneous or Staged Decompressions for Patients with Tandem Spinal Stenosis.

OBJECTIVE: To compare the clinical effects of cervical decompression first, lumbar decompression first, or simultaneous decompression of both lesions in the treatment of tandem spinal stenosis (TSS). METHODS: This is a retrospective analysis. From January 2013 to December 2018, 51 TSS patients underwent our surgery and postoperative investigation. Among the 51 subjects, 27 females and 24 males, aged 49-77 years with an average age of 66.3 ± 6.8, were selected. According to the different operation sequences, all patients were divided into three groups. In simultaneous operation group, five patients underwent cervical and lumbar vertebrae surgery at the same time. In first cervical surgery group, 28 patients underwent cervical vertebra surgery first, followed by lumbar spine surgery after a period of recovery. And in first lumbar surgery group, 18 patients underwent lumbar vertebrae surgery first. The choice for neck surgery is posterior cervical single-door vertebroplasty, the surgery of lumber is plate excision and decompression needle-rod system internal fixation. The outcome measures are visual analogue scale (VAS), Japanese Orthopaedic Association cervical (JOA-C) and lumbar (JOA-L) scores, which were assessed at 3 months and 1 year after the operation by telephone interview. In addition, operative time, estimated blood loss, and hospital stay were also recorded. RESULTS: All the patients in the study had surgery performed successfully by the same group of orthopaedic surgeons. The preoperative VAS scores of simultaneous operation group, first cervical surgery group, and first lumbar surgery group were 8.00 ± 1.00, 8.36 ± 0.68, and 8.17 ± 0.71 (P > 0.05). The preoperative JOA-C scores were 7.00 ± 2.35, 6.54 ± 1.53, and 7.83 ± 1.04 (P < 0.05). And the preoperative JOA-L scores were 7.20 ± 2.17, 4.64 ± 2.36, and 5.78 ± 1.22 respectively (P < 0.05). During the final 1-year follow-up, the JOA-C improvement rates of simultaneous operation group, first cervical surgery group, and first lumbar surgery group were 85.68% ± 5.44%, 84.27% ± 5.02%, and 83.34% ± 10.25%, respectively (P > 0.05), and the JOA-L improvement rates were 80.04% ± 3.35%, 81.65% ± 3.74%, and 80.21% ± 4.76% (P > 0.05). The difference among them was not statistically significant. In addition, operation time (OP), blood loss (BL), and hospital stay (HS) in the simultaneous operation group were 245.00 ± 5.00 min, 480.00 ± 27.39 mL, and 16.60 ± 0.55 days, respectively. While those parameters in the first cervical surgery group were 342.50 ± 18.18 min, 528.21 ± 43.97 mL, and 22.75 ± 2.15 days, and in the first lumbar surgery group they were 346.11 ± 24.77 min, 519.44 ± 43.99 mL, and 22.89 ± 1.64 days. The average blood loss in simultaneous operation group was less (P > 0.05); meanwhile, the operation time and hospital stay time were significantly shorter in the simultaneous operation group than in the first cervical surgery group and first lumbar surgery group (P < 0.05). Only one case of fat liquefaction occurred in first cervical surgery group, which healed spontaneously after a regular change of dressing for 1 month. CONCLUSIONS: Under the condition of ensuring the surgical effect, the choice of staged surgery or concurrent surgery according to the patients' own symptoms of cervical and lumbar symptoms could both obtain satisfactory results, and the damage of simultaneous surgery was less than that of staged surgery.

The role of fibroblast activation protein in progression and development of osteosarcoma cells.

To investigate the expression levels of fibroblast activation protein (FAP) in human osteosarcoma tissues and its possible correlations with clinical pathological characteristics of patients with osteosarcoma, and to explore the potential effects of FAP on progression and development of osteosarcoma. Immunohistochemistry (IHC) assay was initially performed to detect the expression levels of FAP in 66 tumor tissues and adjacent non-tumor tissues. Patients were sequentially divided into two groups based on different expression levels of FAP. The correlations between the expression levels of FAP and the clinical pathological characteristics were investigated, and the role of FAP in proliferation, migration, and invasion of osteosarcoma cells was assessed via colony formation, MTT, wound healing, and transwell assays, respectively. The possible effects of FAP on tumor growth and metastasis were evaluated in vivo. We further attempted to reveal the underlying mechanism of FAP involved in tumor growth through bioinformatics and IHC assays. High expression levels of FAP were noted in human osteosarcoma tissues. It also was unveiled that FAP was significantly associated with the tumor size (P = 0.005*) and clinical stage (P = 0.017*). Our data further confirmed that knockdown of FAP remarkably blocked proliferation, migration, and invasion of osteosarcoma cells in vitro, and suppressed tumor growth and metastasis in mice via AKT signaling pathway. The possible role of FAP in progression and development of osteosarcoma could be figured out. Our data may be helpful to develop a novel therapeutic target for the treatment of osteosarcoma.