Large skin defect in Type V aplasia cutis congenita treated with conservative treatment: a case report.

Aplasia cutis congenita (ACC) is a congenital disorder that can be classified into nine types, with Type I ACC being the most common. Type V ACC associated with fetus papyraceus is a rare subtype of ACC. We report the case of a Type V ACC in a male newborn with extensive abdominal skin defects. The patient received conservative treatment using hydrogel foam and silicone foam dressings. Approximately five weeks later, the patient was discharged when more than 60% of the skin had completed epithelialization. After discharge from West China Second University Hospital, Chengdu , the patient continued to be followed up regularly at the Burns and Plastic Surgery Clinic at local hospital in Gansu. We followed up the child by telephone. After 4 months of follow-up, scar tissue formation was observed in the trunk area. The infant is 2 years and 5 months old now, physical examination did not reveal any organ problems.

Bone mesenchymal stem cells improve cholestatic liver fibrosis by targeting ULK1 to regulate autophagy through PI3K/AKT/mTOR pathway.

Cholestatic liver disease (CLD) is a severe disease, which can progress to liver cirrhosis, even liver cancer. Hepatic stellate cells (HSCs) activation plays a crucial role in CLD development. Bone mesenchymal stem cells (BMSCs) treatment was demonstrated to be beneficial in liver diseases. However, the therapeutic effect and mechanism of BMSCs on CLD are poorly known. In the present study, we investigated the therapeutic effects and underlying mechanisms of BMSCs transplantation in mouse models of bile duct ligation-induced cholestatic liver fibrosis (CLF). The results revealed that BMSCs significantly improved liver function and reduced the formation of fibrosis after portal vein transplantation. Mechanistically, after coculturing BMSCs and HSCs, we identified that BMSCs alleviated starvation-induced HSCs activation. Further, BMSCs inhibited HSCs activation by decreasing autophagy, and PI3K/AKT/mTOR pathway was involved in the regulation. More importantly, ULK1 is identified as the main autophagy-related gene regulated by BMSCs in HSCs autophagy. Overexpression of ULK1 reversed the suppression of HSCs autophagy by BMSCs. Collectively, our results provide a theoretical basis for BMSCs targeting ULK1 to attenuate HSCs autophagy and activation and suggest that BMSCs or ULK1 may be an alternative therapeutic approach/target for the treatment of CLF.

Inspecting mother-to-infant microbiota transmission: disturbance of strain inheritance by cesarian section.

Introduction: The initial acquisition and subsequent development of the microbiota in early life is crucial to future health. Cesarean-section (CS) birth is considered to affect early microbial transmission from mother to infant. Methods: In this study, we collected fecal samples from 34 CS infants and their mothers from West China Second Hospital, Sichuan University to assess the microbiota developmental trajectory of mothers and infants. We explored mother-infant gut microbiome transmission via comparison with corresponding Finnish data. Results: Metagenomic analysis of gut microbiota profiles indicated that the communities of mothers and infants were distinct. The composition of the infant gut microbiome was highly variable but also followed predictable patterns in the early stages of life. Maternal communities were stable and mainly dominated by species from Bacteroidacea spp. We used PStrain to analyze and visualize strain transmission in each mother-infant pair. Excluding missing data, we included 32 mother-infant pairs for analysis of strain transmission. Most CS deliveries (65.6%, 21/32) did not demonstrate transmission of strains from mother to infant. To further explore the mother-infant strain transmission, we analyzed metagenomics data from Finnish mother-infant pairs. A total of 32 mother-infant pairs were included in the analysis, including 28 vaginal delivery (VD) infants and four CS infants. Strain transmission was observed in 30 infants, including 28 VD infants and two CS infants. All VD infants received transmitted stains from their mothers. Finally, a total of 193 strain transmission events were observed, comprising 131 strains and 45 species. Discussion: Taken together, our data suggested that delivery mode was an important factor influencing the mother-infant strain transmission.

High purity of human secreted phospholipase A2 group IIE in Pichia pastoris using basal salts medium comparison with YPD medium.

Secreted phospholipase A2s (sPLA2s) are a group of enzymes with 6-8 disulfide bonds that participate in numerous physiological processes by catalyzing the hydrolysis of phospholipids at the sn-2 position. Due to their high content of disulfide bonds and hydrolytic activity toward cell membranes, obtaining the protein of sPLA2s in the soluble and active form is challenging, which hampers their functional study. In this study, one member of recombinant human sPLA2s, tag-free group IIE (GIIE), was expressed in Pichia pastoris. The protein GIIE was purified from the crude culture supernatant by a two-step chromatography procedure, a combination of cation exchange and size-exclusion chromatography. In the shake flask fermentation, Protein of GIIE with higher purity was successfully obtained, using basal salts medium (BSM) instead of YPD medium. In the large-scale fermentation, each liter of BSM produced a final yield of 1.2 mg pure protein GIIE. This protocol will facilitate further research of GIIE and provide references for the production of other sPLA2 members.

Silver dressing in the management of an infant's urachal anomaly infected with methicillin-resistant Staphylococcus aureus: A case report.

BACKGROUND: Symptomatic urachal anomalies are rare disorders. The management of urachal remnants has historically been surgical excision because of the connection between urachal remnants and risk of malignancy development later in life. However, recent literature suggests that urachal anomalies that do not extend to the bladder can be treated with conservative management. In this case, we report a newborn with an infected urachal remnant who was treated with a combination of antibiotics and a silver-based dressing and finally recovered well. CASE SUMMARY: Female baby A, weighing 2.88 kg at 38+5 wk of gestational age, was referred to the hospital because of a red, swollen umbilicus approximately 2 cm × 2 cm in size with yellow purulent exudate. Through physical and ultrasound examination, the baby was finally diagnosed with a urachal anomaly. We first used oxacillin to prevent infection for 3 d. On the 4th day, microbiology testing of the umbilical exudate revealed the presence of methicillin-resistant Staphylococcus aureus (MRSA). We changed the treatment with oxacillin to vancomycin for systemic infection and treated the umbilical inflammation with a silver sulfate dressing. After 5 d, the symptoms of the umbilicus disappeared, and we discontinued silver dressing application. On the 12th day, umbilical exudate testing was negative for MRSA. On the 14th day, the baby's blood testing showed a white blood cell count of 14.7 × 109/L, neutrophil percentage of 27.8%, and C-reactive protein level of 1.0 mg/L, suggesting that the infection had been controlled. We stopped treatment, and the baby was discharged with no complications. In this case, the infected urachal anomaly was cured with silver dressing and antibiotic application instead of surgical methods, which was a different course from that of some other urachal remnant cases. CONCLUSION: Anomalies that do not connect with the bladder can be treated with nonoperative management, including application of conservative antibiotics and local intervention with silver-based dressings. Silver sulfate dressings are absolutely safe for neonates with judicious use, and they play an established role in preventing infection without resistance, which is a common problem with other antibiotics and antiseptics.

[Effect of E54 mutation of human secreted phospholipase A2 GIIE on substrate selectivity].

Human secreted phospholipase A2 GIIE (hGIIE) is involved in inflammation and lipid metabolism due to its ability of hydrolyzing phospholipids. To reveal the mechanism of substrate head-group selectivity, we analyzed the effect of mutation of hGIIE on its activity and selectivity. hGIIE structural analysis showed that E54 might be related to its substrate head-group selectivity. According to the sequence alignment, E54 was mutated to alanine, phenylalanine, and lysine. Mutated genes were cloned and expressed in Pichia pastoris X33, and the enzymes with mutations were purified with 90% purity by ion exchange and molecular size exclusion chromatography. The enzymatic activities were determined by isothermal microthermal titration method. The Km of mutant E54K towards 1,2-dihexyl phosphate glycerol decreased by 0.39-fold compared with that of wild type hGIIE (WT), and the Km of E54F towards 1,2-dihexanoyl-sn-glycero-3-phosphocholine increased by 1.93-fold than that of WT. The affinity of mutant proteins with phospholipid substrate was significantly changed, indicating that E54 plays an important role in the substrate head-group selectivity of hGIIE.

The atypical binding mechanism of second calcium on phospholipase A2 group IIE.

Secreted phospholipase A2s (sPLA2s) are calcium dependent enzymes involved in various biological events such as lipid metabolism and inflammation. We previously identified the second calcium (Ca2) binding site of human sPLA2 Group IIE (hGIIE) by structural study and suggested that Asn21 act as the switch of Ca2 binding to modulate the enzymatic activity, but the detailed Ca2 binding mechanism is still unclear. Combined with enzymatic assay, model analysis and calcium binding affinity data for mutated hGIIE proteins, we herein further demonstrate that the flexibly bound Ca2 is essential for the catalysis of hGIIE, unlike the stable binding of Ca2 in hGIIA that replenishes the calcium in the typical loop during the reaction. The atypical Ca2 binding feature of hGIIE will provide a better understanding on the catalytic mechanism of hGIIE.

Residue Asn21 acts as a switch for calcium binding to modulate the enzymatic activity of human phospholipase A2 group IIE.

Secreted phospholipases A2 (sPLA2) group IIE (GIIE) is involved in several biological events, such as lipid metabolism and possibly inflammation that may mainly depend on its catalytic reaction. We previously showed that Asn21 is a critical residue that contributes to the enzymatic activity of hGIIE, but the underlying mechanism is still not clear. Here, combined with crystal structures and mutagenesis studies of the Asn21Gly mutant, we demonstrate that Asn21 acts as a switch responsible for the calcium binding and the catalytic efficiency. Our results of the atypical feature of calcium binding in hGIIE not only provide clues to understand the molecular basis of its enzymatic activity and physiological function, but also confer improved specificity for potential inhibitor design of sPLA2.

Structural basis for functional selectivity and ligand recognition revealed by crystal structures of human secreted phospholipase A2 group IIE.

Secreted phospholipases A2s (sPLA2s) are involved in various pathological conditions such as rheumatoid arthritis and cardiovascular disease. Many inhibitors were developed and studied in clinical trials, but none have reached the market yet. This failure may be attributed to the lack of subtype selectivity for these inhibitors. Therefore, more structural information for subtype sPLA2 is needed to guide the selective inhibitor development. In this study, the crystal structure of human sPLA2 Group IIE (hGIIE), coupled with mutagenesis experiments, proved that the flexible second calcium binding site and residue Asn21 in hGIIE are essential to its enzymatic activity. Five inhibitor bound hGIIE complex structures revealed the key residues (Asn21 and Gly6) of hGIIE that are responsible for interacting with inhibitors, and illustrated the difference in the inhibitor binding pocket with other sPLA2s. This will facilitate the structure-based design of sPLA2's selective inhibitors.

Crystal structure of a lipase from Streptomyces sp. strain W007 - implications for thermostability and regiospecificity.

MAS1 from marine Streptomyces sp. strain W007 belongs to the bacterial lipase I.7 subfamily and is characterized as a thermostable and nonregiospecific lipase. To shed light on the catalytic mechanism of MAS1, we determined its crystal structure with closed conformation in two crystal forms at 2.3 Å resolution. MAS1 adopts the canonical α/ß hydrolase core fold with its catalytic triad being formed by S109, D200 and H232. Structural analysis and biochemical assays revealed that disulfide bonds and salt bridges play a vital role in the thermostability of MAS1. In addition, we discovered that the replacement of H108 with a tryptophan converts MAS1 from a nonregiospecific to an sn-1,3-specific lipase, suggesting the functional importance of the second position from the conserved pentapeptide motif in defining the regiospecificity of MAS1. Our present study provides insights into the molecular basis for the thermostability and regiospecificity of MAS1, and it may aid in the rational design of thermostable or regiospecific lipases for potential industrial applications. DATABASE: Structural data are available in the Protein Data Bank database under the accession numbers 5H6B and 5H6G.

An inhibition model of BPTI to unlinked dengue virus NS2B-NS3 protease.

One approach to treating the dengue virus infection is to inhibit its NS2B-NS3 protease that plays a vital role in virus maturation. However, the lack of structural information on the active conformation of the protease hindered related drug design. With a co-expression system, we obtained the active two-component protease in its unlinked form. BPTI shows strong competitive inhibitory activity (Ki = 6.5 nM) against this unlinked protease, which adopts a closed conformation. Based on the biochemical and NMR perturbation information, an inhibition model of BPTI to NS2B-NS3 protease is proposed.

Crystal structure of a mono- and diacylglycerol lipase from Malassezia globosa reveals a novel lid conformation and insights into the substrate specificity.

Most lipases contain a lid domain to shield the hydrophobic binding site from the water environment. The lid, mostly in helical form, can undergo a conformational change to expose the active cleft during the interfacial activation. Here we report the crystal structures of Malassezia globosa LIP1 (SMG1) at 1.45 and 2.60 Å resolution in two crystal forms. The structures present SMG1 in its closed form, with a novel lid in loop conformation. SMG1 is one of the few members in the fungal lipase family that has been found to be strictly specific for mono- and diacylglycerol. To date, the mechanism for this substrate specificity remains largely unknown. To investigate the substrate binding properties, we built a model of SMG1 in open conformation. Based on this model, we found that the two bulky hydrophobic residues adjacent to the catalytic site and the N-terminal hinge region of the lid both may act as steric hindrances for triacylglycerols binding. These unique structural features of SMG1 will provide a better understanding on the substrate specificity of mono- and diacylglycerol lipases and a platform for further functional study of this enzyme.

Optimal production and biochemical properties of a lipase from Candida albicans.

Lipases from microorganisms have multi-faceted properties and play an important role in ever-growing modern biotechnology and, consequently, it is of great significance to develop new ones. In the present work, a lipase gene from Candida albicans (CaLIP10) was cloned and two non-unusual CUG serine codons were mutated into universal codons, and its expression in Pichia pastoris performed optimally, as shown by response surface methodology. Optimal conditions were: initial pH of culture 6.86, temperature 25.53 °C, 3.48% of glucose and 1.32% of yeast extract. The corresponding maximal lipolytic activity of CaLIP10 was 8.06 U/mL. The purified CaLIP10 showed maximal activity at pH 8.0 and 25 °C, and a good resistance to non-ionic surfactants and polar organic solvent was noticed. CaLIP10 could effectively hydrolyze coconut oil, but exhibited no obvious preference to the fatty acids with different carbon length, and diacylglycerol was accumulated in the reaction products, suggesting that CaLIP10 is a potential lipase for the oil industry.