Recent progress in strategies for steroid production in yeasts.

As essential structural molecules of fungal cell membrane, ergosterol is not only an important component of fungal growth and stress-resistance but also a key precursor for manufacturing steroid drugs of pharmaceutical or agricultural significance. So far, ergosterol biosynthesis in yeast has been elucidated elaborately, and efforts have been made to increase ergosterol production through regulation of ergosterol metabolism and storage. Furthermore, the same intermediates shared by yeasts and animals or plants make the construction of heterologous sterol pathways in yeast a promising approach to synthesize valuable steroids, such as phytosteroids and animal steroid hormones. During these challenging processes, several obstacles have arisen and been combated with great endeavors. This paper reviews recent research progress of yeast metabolic engineering for improving the production of ergosterol and heterologous steroids. The remaining tactics are also discussed.

Coding mutations in NUS1 contribute to Parkinson's disease.

Whole-exome sequencing has been successful in identifying genetic factors contributing to familial or sporadic Parkinson's disease (PD). However, this approach has not been applied to explore the impact of de novo mutations on PD pathogenesis. Here, we sequenced the exomes of 39 early onset patients, their parents, and 20 unaffected siblings to investigate the effects of de novo mutations on PD. We identified 12 genes with de novo mutations (MAD1L1, NUP98, PPP2CB, PKMYT1, TRIM24, CEP131, CTTNBP2, NUS1, SMPD3, MGRN1, IFI35, and RUSC2), which could be functionally relevant to PD pathogenesis. Further analyses of two independent case-control cohorts (1,852 patients and 1,565 controls in one cohort and 3,237 patients and 2,858 controls in the other) revealed that NUS1 harbors significantly more rare nonsynonymous variants (P = 1.01E-5, odds ratio = 11.3) in PD patients than in controls. Functional studies in Drosophila demonstrated that the loss of NUS1 could reduce the climbing ability, dopamine level, and number of dopaminergic neurons in 30-day-old flies and could induce apoptosis in fly brain. Together, our data suggest that de novo mutations could contribute to early onset PD pathogenesis and identify NUS1 as a candidate gene for PD.

Characterization of CTX-M-140, a Variant of CTX-M-14 Extended-Spectrum ß-Lactamase with Decreased Cephalosporin Hydrolytic Activity, from Cephalosporin-Resistant Proteus mirabilis.

CTX-M-140, a novel CTX-M-type extended-spectrum ß-lactamase (ESBL), was identified in cephalosporin-resistant clinical isolates of Proteus mirabilis CTX-M-140 contained an alanine-to-threonine substitution at position 109 compared to its putative progenitor, CTX-M-14. When it was expressed in an Escherichia coli isogenic background, CTX-M-140 conferred 4- to 32-fold lower MICs of cephalosporins than those with CTX-M-14, indicating that the phenotype was attributable to this single substitution. For four mutants of CTX-M-14 that were constructed by site-directed mutagenesis (A109E, A109D, A109K, and A109R mutants), MICs of cephalosporins were similar to those for the E. coli host strain, which suggested that the alanine at position 109 was essential for cephalosporin hydrolysis. The kinetic properties of native CTX-M-14 and CTX-M-140 were consistent with the MICs for the E. coli clones. Compared with that of CTX-M-14, a lower hydrolytic activity against cephalosporins was observed for CTX-M-140. blaCTX-M-140 is located on the chromosome as determined by I-CeuI pulsed-field gel electrophoresis (I-CeuI-PFGE) and Southern hybridization. The genetic environment surrounding blaCTX-M-140 is identical to the sequence found in different plasmids with blaCTX-M-9-group genes among the Enterobacteriaceae Genome sequencing and analysis showed that P. mirabilis strains with blaCTX-M-140 have a genome size of ∼4 Mbp, with a GC content of 38.7% and 23 putative antibiotic resistance genes. Our results indicate that alanine at position 109 is critical for the hydrolytic activity of CTX-M-14 against oxyimino-cephalosporins.

Combined Biosynthetic Pathway Engineering and Storage Pool Expansion for High-Level Production of Ergosterol in Industrial Saccharomyces cerevisiae.

Ergosterol, a terpenoid compound produced by fungi, is an economically important metabolite serving as the direct precursor of steroid drugs. Herein, ergsosterol biosynthetic pathway modification combined with storage capacity enhancement was proposed to synergistically improve the production of ergosterol in Saccharomyces cerevisiae. S. cerevisiae strain S1 accumulated the highest amount of ergosterol [7.8 mg/g dry cell weight (DCW)] among the wild-type yeast strains tested and was first selected as the host for subsequent metabolic engineering studies. Then, the push and pull of ergosterol biosynthesis were engineered to increase the metabolic flux, overexpression of the sterol acyltransferase gene ARE2 increased ergosterol content to 10 mg/g DCW and additional overexpression of a global regulatory factor allele (UPC2-1) increased the ergosterol content to 16.7 mg/g DCW. Furthermore, considering the hydrophobicity sterol esters and accumulation in lipid droplets, the fatty acid biosynthetic pathway was enhanced to expand the storage pool for ergosterol. Overexpression of ACC1 coding for the acetyl-CoA carboxylase increased ergosterol content from 16.7 to 20.7 mg/g DCW. To address growth inhibition resulted from premature accumulation of ergosterol, auto-inducible promoters were employed to dynamically control the expression of ARE2, UPC2-1, and ACC1. Consequently, better cell growth led to an increase of ergosterol content to 40.6 mg/g DCW, which is 4.2-fold higher than that of the starting strain. Finally, a two-stage feeding strategy was employed for high-density cell fermentation, with an ergosterol yield of 2986.7 mg/L and content of 29.5 mg/g DCW. This study provided an effective approach for the production of ergosterol and other related terpenoid molecules.

The differential profiles of long non-coding RNAs between rheumatoid arthritis and gouty arthritis.

OBJECTIVE: This study was designed to determine the differential profiles of long non-coding RNAs (lncRNAs) between rheumatoid arthritis (RA) and gouty arthritis (GA), which may lead to the discovery of specific biomarkers for RA diagnosis and treatment in the future. METHODS: The profiles of lncRNAs were determined by Agilent microarray. Bioinformatics analyses, including Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, of the large dataset obtained from microarray experiments were performed. RESULTS: A total of 765 lncRNAs and 2,808 mRNAs were significantly and differentially expressed in RA samples as compared to GA samples. Moreover, of 2,808 differentially expressed mRNAs, 178 upregulated mRNAs and 21 downregulated mRNAs were identified to be strongly correlated with lncRNAs examined in this study. Bioinformatics analyses revealed the tumor-like phenotype of synovial cells in RA and the involvement of immune system process in GA. In addition, this study demonstrated the significantly different molecular origins of two Chinese Medicine syndrome patterns of RA patients -- blood stasis and non-blood stasis. CONCLUSIONS: Our study showed for the first time the differentially expressed lncRNA profiles in synovial tissues between RA and GA and between two clinical phenotypes of RA patients differentiated by Chinese Medicine. This study helps achieving personalized medicine in RA. Larger-scale studies are required to validate the data presented.

Psychosomatic Status, Personality Traits, and Coping Styles of Bereaved and Non-Bereaved Survivors of the 2008 Wenchuan Earthquake, China.

OBJECTIVES: This study examined personality, coping styles, and psychosomatic characteristics and their relationships in bereaved and non-bereaved earthquake survivors. STUDY DESIGN: Cross-sectional survey. METHODS: A survey was conducted with a sample of 102 non-bereaved survivors and 79 bereaved survivors from Mianyang, Anyang, and similar districts 2 weeks after Wenchuan earthquake. Survivors completed questionnaires, including items about demographics, personality characteristics, coping styles, and psychosomatic status. RESULTS: Bereaved survivors had lower scores for gregariousness, trust, and optimism, but higher scores for depressed mood, loneliness, becoming easily fearful, irritation, and anxiety than non-bereaved survivors. In addition, bereaved participants scored higher for avoiding problems, self-blame, and fantasy coping styles than non-bereaved ones. Personality and coping styles significantly correlated with psychosomatic status in bereaved and non-bereaved survivors. Optimism and openness to feelings personality characteristics, and self-blame, avoiding problems, and rationalization coping styles significantly predicted psychosomatic status of bereaved survivors, whereas openness to fantasy, optimism, order, and trust personality characteristics, and self-blame and avoiding problems coping styles significantly predicted psychosomatic status of non-bereaved survivors. CONCLUSION: Earthquake survivors experienced post-traumatic stress disorder (PTSD) symptoms and negative emotions. Bereaved survivors experienced more serious PTSD symptoms and negative emotions relative to non-bereaved survivors. Appropriate psychological crisis interventions should be conducted for earthquake survivors, especially bereaved survivors.