Metabolic engineering of Saccharomyces cerevisiae for production of germacrene A, a precursor of beta-elemene

Beta-elemene, a sesquiterpene and the major component of the medicinal herb Curcuma wenyujin, has antitumor activity against various types of cancer and could potentially serve as a potent antineoplastic drug. However, its current mode of production through extraction from plants has been inefficient and suffers from limited natural resources. Here, we engineered a yeast cell factory for the sustainable production of germacrene A, which can be transformed to beta-elemene by a one-step chemical reaction in vitro. Two heterologous germacrene A synthases (GASs) converting farnesyl pyrophosphate (FPP) to germacrene A were evaluated in yeast for their ability to produce germacrene A. Thereafter, several metabolic engineering strategies were used to improve the production level. Overexpression of truncated 3-hydroxyl-3-methylglutaryl-CoA reductase and fusion of FPP synthase with GAS, led to a sixfold increase in germacrene A production in shake-flask culture. Finally, 190.7 mg/l of germacrene A was achieved. The results reported in this study represent the highest titer of germacrene A reported to date. These results provide a basis for creating an efficient route for further industrial application re-placing the traditional extraction of beta-elemene from plant sources

Increased Drp1 promotes autophagy and ESCC progression by mtDNA stress mediated cGAS-STING pathway.

Background: Mitochondrial dynamics homeostasis is important for cell metabolism, growth, proliferation, and immune responses. The critical GTPase for mitochondrial fission, Drp1 is frequently upregulated in many cancers and is closely implicated in tumorigenesis. However, the mechanism underling Drp1 to influence tumor progression is largely unknown, especially in esophageal squamous cell carcinoma (ESCC). Methods: Immunohistochemistry was used to examine Drp1 and LC3B expression in tissues of ESCC patients. Autophagic vesicles were investigated by transmission electron microscopy. Fluorescent LC3B puncta and mitochondrial nucleoid were observed by fluorescent and confocal microscopy. Mitochondrial function was evaluated by mitochondrial membrane potential, ROS and ATP levels. Xenograft tumor model was performed in BALB/c nude mice to analyze the role of Drp1 on ESCC progression. Results: We found that Drp1 high expression is correlated with poor overall survival of ESCC patients. Drp1 overexpression promotes cell proliferation and xenograft ESCC tumor growth by triggering autophagy. Furthermore, we demonstrated that Drp1 overexpression disturbs mitochondrial function and subsequent induces mitochondrial DNA (mtDNA) released into the cytosol thereby inducing cytosolic mtDNA stress. Mechanistically, cytosolic mtDNA activates the cGAS-STING pathway and facilitates autophagy, which promotes ESCC cancer growth. Moreover, mtDNA digestion with DNase I and autophagy inhibition with chloroquine attenuates the cGAS-STING pathway activation and ESCC cancer growth. Conclusions: Our finding reveals that Drp1 overexpression induces mitochondrial dysfunction and cytosolic mtDNA stress, which subsequently activates the cGAS-STING pathway, triggers autophagy and promotes ESCC progression

Examining the generalizability of research findings from archival data

This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability—for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples

The complete mitochondrial genome of Cuspidaria undata (Bivalvia, Anomalodesmata, Cuspidariidae)

The mitochondrial genome of Cuspidaria undata (Verrill, 1884) was sequenced in full using Illumina HiSeq 2500. The circular mitochondrial DNA (mtDNA) was 16,266 bp in size, encoded 37 genes, and contained 13 protein-coding genes (PCGs), 2 rRNAs and 22 tRNAs. The gene order of the 13 PCGs in this species exhibited extensive rearrangement and differences in comparison to other Cuspidariidae, indicating that gene order is not conserved within this family. Phylogenetic analysis based on 13 PCGs and 2 rRNAs recovered a monophyletic Cuspidariidae

Molecular Cloning and Expression Analysis of the Cryptochrome Gene <i>CiPlant-CRY1</i> in Antarctic Ice Alga <i>Chlamydomonas</i> sp. ICE-L

Cryptochrome (CRY) is a kind of flavin-binding protein that can sense blue light and near-ultraviolet light, and participates in the light response of organisms and the regulation of the circadian clock. The complete open reading frame (ORF) of CiPlant-CRY1 (GenBank ID OM389130.1), encoding one kind of CRY, was cloned from the Antarctic ice alga Chlamydomonas sp. ICE-L. The quantitative real-time PCR study showed that the expression level of the CiPlant-CRY1 gene was the highest at 5 °C and salinity of 32‰. CiPlant-CRY1 was positively regulated by blue or yellow light, suggesting that it is involved in the establishment of photomorphology. The CiPlant-CRY1 gene can respond to polar day and polar night, indicating its expression is regulated by circadian rhythm. The expression level of CiPlant-CRY1 was most affected by UVB irradiation, which may be related to the adaptation of ice algae to a strong ultraviolet radiation environment. Moreover, the recombinant protein of CiPlant-CRY1 was expressed by prokaryotic expression. This study may be important for exploring the light-induced rhythm regulation of Antarctic ice algae in the polar marine environment

Psychological Stress and Gut Microbiota Composition: A Systematic Review of Human Studies

Introduction: The associations between psychological stress and gut microbiota composition are not fully understood. This study investigated associations between psychological stress and gut microbiota composition and examined the potential modifying effects of age, sex, and ethnicity on such associations. Methods: A systematic literature search was conducted using PubMed, Web of Science, PsycINFO, and Embase databases for studies published until November 2021 which examined associations between psychological stress and gut microbiota composition. Results: During the search process, 10,790 studies were identified, and after screening, 13 met the eligibility criteria and were included. The median sample size was 70, and the median age of participants was 28.0 years. Most of the included studies did not report associations between measures of alpha- and beta diversity of the gut microbiota composition and psychological stress. A few studies reported that the Shannon index, Chao 1, Simpson index, and weighted UniFrac were negatively associated with psychological stress. Significant reductions in several taxa at the phyla-, family-, and genus-levels were observed in participants with higher psychological stress. At the phylum level, the abundance of Proteobacteria and Verrucomicrobia were negatively associated with psychological stress. At the family-level, no more than two studies reported associations of the same microbiota with psychological stress. At the genus level, the following results were found in more than two studies; psychological stress was negatively associated with the abundance of Lachnospira, Lachnospiraceae, Phascolarctobacterium, Sutterella, and Veillonella, and positively associated with the abundance of Methanobrevibacter, Rhodococcus, and Roseburia. However, it was not possible to determine the influence of age, sex, or ethnicity due to the limited studies included. Conclusion: Our findings provide evidence that psychological stress is associated with changes in the abundance of the gut microbiota. Larger sample longitudinal studies are needed to determine the causal relationship between psychological stress and the gut microbiota

In Vitro and In Vivo Antioxidant Activities of the Flowers and Leaves from Paeonia rockii and Identification of Their Antioxidant Constituents by UHPLC-ESI-HRMSn via Pre-Column DPPH Reaction

The genus Paeonia, also known as the “King of Flowers” in China, is an important source of traditional Chinese medicine (TCM). Plants of this genus have been used to treat a range of cardiovascular and gynecological diseases. However, the potential pharmacological activity of one particular species, Paeonia rockii, has not been fully investigated. In the first part of the present study, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), reducing power assays, and metal ion chelating assays were used to investigate the in vitro antioxidant activities of Paeonia rockii. In the second portion of the study, a mouse model of d-galactose-induced aging was used to validate the antioxidant effects of the flowers from Paeonia rockii in vivo. Lastly, potential antioxidant constituents were screened and identified by ultra-high pressure liquid chromatography and electrospray ionization coupled with high-resolution mass spectrometry (UHPLC-ESI-HRMSn) combined with the DPPH assay. Results indicated that the flowers and leaves exhibited stronger antioxidant activity than ascorbic acid in vitro. The therapeutic effect of Paeonia rockii was determined in relation to the levels of biochemical indicators, such as 8-iso-prostaglandin F2α (8-iso PGF2α) in the serum, superoxide dismutase (SOD), protein carbonyl, malondialdehyde (MDA), and glutathione (GSH) in the liver and brain, after daily intra-gastric administration of different concentrations of extracts (100, 200 and 400 mg/kg) for three weeks. The levels of 8-iso PGF2α (p &lt; 0.01) and protein carbonyl groups (p &lt; 0.01) were significantly reduced, whereas those of SOD (p &lt; 0.05) had significantly increased, indicating that components of the flowers of Paeonia rockii had favorable antioxidant activities in vivo. Furthermore, UHPLC-ESI-HRMSn, combined with pre-column DPPH reaction, detected 25 potential antioxidant compounds. Of these, 18 compounds were tentatively identified, including 11 flavonoids, four phenolic acids, two tannins, and one monoterpene glycoside. This study concluded that the leaves and flowers from Paeonia rockii possess excellent antioxidant properties, highlighting their candidacy as “new” antioxidants, which can be utilized therapeutically to protect the body from diseases caused by oxidative stress