Redox Regulation in Cancer Stem Cells

Reactive oxygen species (ROS) and ROS-dependent (redox regulation) signaling pathways and transcriptional activities are thought to be critical in stem cell self-renewal and differentiation during growth and organogenesis. Aberrant ROS burst and dysregulation of those ROS-dependent cellular processes are strongly associated with human diseases including many cancers. ROS levels are elevated in cancer cells partially due to their higher metabolism rate. In the past 15 years, the concept of cancer stem cells (CSCs) has been gaining ground as the subpopulation of cancer cells with stem cell-like properties and characteristics have been identified in various cancers. CSCs possess low levels of ROS and are responsible for cancer recurrence after chemotherapy or radiotherapy. Unfortunately, how CSCs control ROS production and scavenging and how ROS-dependent signaling pathways contribute to CSCs function remain poorly understood. This review focuses on the role of redox balance, especially in ROS-dependent cellular processes in cancer stem cells (CSCs). We updated recent advances in our understanding of ROS generation and elimination in CSCs and their effects on CSC self-renewal and differentiation through modulating signaling pathways and transcriptional activities. The review concludes that targeting CSCs by manipulating ROS metabolism/dependent pathways may be an effective approach for improving cancer treatment

Gut Bacterial Communities of Lymantria xylina and Their Associations with Host Development and Diet

The gut microbiota of insects has a wide range of effects on host nutrition, physiology, and behavior. The structure of gut microbiota may also be shaped by their environment, causing them to adjust to their hosts; thus, the objective of this study was to examine variations in the morphological traits and gut microbiota of Lymantria xylina in response to natural and artificial diets using high-throughput sequencing. Regarding morphology, the head widths for larvae fed on a sterilized artificial diet were smaller than for larvae fed on a non-sterilized host-plant diet in the early instars. The gut microbiota diversity of L. xylina fed on different diets varied significantly, but did not change during different development periods. This seemed to indicate that vertical inheritance occurred in L. xylina mutualistic symbionts. Acinetobacter and Enterococcus were dominant in/on eggs. In the first instar larvae, Acinetobacter accounted for 33.52% of the sterilized artificial diet treatment, while Enterococcus (67.88%) was the predominant bacteria for the non-sterilized host-plant diet treatment. Gut microbe structures were adapted to both diets through vertical inheritance and self-regulation. This study clarified the impacts of microbial symbiosis on L. xylina and might provide new possibilities for improving the control of these bacteria

Combining Metabolomics and Transcriptomics to Characterize Tanshinone Biosynthesis in Salvia Miltiorrhiza

Plant natural products have been co-opted for millennia by humans for various uses such as flavor, fragrances, and medicines. These compounds often are only produced in relatively low amounts and are difficult to chemically synthesize, limiting access. While elucidation of the underlying biosynthetic processes might help alleviate these issues (e.g., via metabolic engineering), investigation of this is hindered by the low levels of relevant gene expression and expansion of the corresponding enzymatic gene families. However, the often-inducible nature of such metabolic processes enables selection of those genes whose expression pattern indicates a role in production of the targeted natural product. Here, we combine metabolomics and transcriptomics to investigate the inducible biosynthesis of the bioactive diterpenoid tanshinones from the Chinese medicinal herb, Salvia miltiorrhiza(Danshen). Untargeted metabolomics investigation of elicited hairy root cultures indicated that tanshinone production was a dominant component of the metabolic response, increasing at later time points. A transcriptomic approach was applied to not only define a comprehensive transcriptome (comprised of 20,972 non-redundant genes), but also its response to induction, revealing 6,358 genes that exhibited differential expression, with significant enrichment for up-regulation of genes involved in stress, stimulus and immune response processes. Consistent with our metabolomics analysis, there appears to be a slower but more sustained increased in transcript levels of known genes from diterpenoid and, more specifically, tanshinone biosynthesis. Among the co-regulated genes were 70 transcription factors and 8 cytochromes P450, providing targets for future investigation. Our results indicate a biphasic response of Danshen terpenoid metabolism to elicitation, with early induction of sesqui- and tri- terpenoid biosynthesis, followed by later and more sustained production of the diterpenoid tanshinones. Our data provides a firm foundation for further elucidation of tanshinone and other inducible natural product metabolism in Danshen

Structure-function analysis of CYP719As involved in methylenedioxy bridge-formation in the biosynthesis of benzylisoquinoline alkaloids and its de novo production

Benzylisoquinoline alkaloids (BIAs) are a type of secondary metabolite with clinical application value. (S)-stylopine is a special BIA which contains methylenedioxy bridge structures. CYP719As could catalyze the methylenedioxy bridge-formation on the A or D rings of protoberberine alkaloids, while displaying significant substrate regiospecificity. To explore the substrate preference of CYP719As, we cloned and identified five CyCYP719A candidates from Corydalis yanhusuo. Two CyCYP719As (CyCYP719A39 and CyCYP719A42) with high catalytic efficiency for the methylenedioxy bridge-formation on the D or A rings were characterized, respectively. The residues (Leu 294 for CyCYP719A42 and Asp 289 for CyCYP719A39) were identified as the key to controlling the regioselectivity of CYP719As affecting the methylenedioxy bridge-formation on the A or D rings by homology modeling and mutation analysis. Furthermore, for de novo production of BIAs, CyCYP719A39, CyCYP719A42, and their mutants were introduced into the (S)-scoulerine-producing yeast to produce 32\ua0mg/L (S)-stylopine. These results lay a foundation for understanding the structure-function relationship of CYP719A-mediated methylenedioxy bridge-formation and provide yeast strains for the BIAs production by\ua0synthetic biology

Catalytic promiscuity of O-methyltransferases from Corydalis yanhusuo leading to the structural diversity of benzylisoquinoline alkaloids

O-methyltransferases play essential roles in producing structural diversity and improving the biological properties of benzylisoquinoline alkaloids (BIAs) in plants. In this study, Corydalis yanhusuo, a plant used in traditional Chinese medicine due to the analgesic effects of its BIA-active compounds, was employed to analyze the catalytic characteristics of O-methyltransferases in the formation of BIA diversity. Seven genes encoding O-methyltransferases were cloned, and functionally characterized using seven potential BIA substrates. Specifically, an O-methyltransferase (CyOMT2) with highly efficient catalytic activity of both 4′- and 6-O-methylations of 1-BIAs was found. CyOMT6 was found to perform two sequential methylations at both 9- and 2-positions of the essential intermediate of tetrahydroprotoberberines, (S)-scoulerine. Two O-methyltransferases (CyOMT5 and CyOMT7) with wide substrate promiscuity were found, with the 2-position of tetrahydroprotoberberines as the preferential catalytic site for CyOMT5 (named scoulerine 2-O-methyltransferase) and the 6-position of 1-BIAs as the preferential site for CyOMT7. In addition, results of integrated phylogenetic molecular docking analysis and site-directed mutation suggested that residues at sites 172, 306, 313, and 314 in CyOMT5 are important for enzyme promiscuity related to O-methylations at the 6- and 7-positions of isoquinoline. Cys at site 253 in CyOMT2 was proved to promote the methylation activity of the 6-position and to expand substrate scopes. This work provides insight into O-methyltransferases in producing BIA diversity in C. yanhusuo and genetic elements for producing BIAs by metabolic engineering and synthetic biology

Expansion within the CYP71D subfamily drives the heterocyclization of tanshinones synthesis in Salvia miltiorrhiza

Tanshinones are the bioactive nor-diterpenoid constituents of the Chinese medicinal herb Danshen (Salvia miltiorrhiza). These groups of chemicals have the characteristic furan D-ring, which differentiates them from the phenolic abietane-type diterpenoids frequently found in the Lamiaceae family. However, how the 14,16-epoxy is formed has not been elucidated. Here, we report an improved genome assembly of Danshen using a highly homozygous genotype. We identify a cytochrome P450 (CYP71D) tandem gene array through gene expansion analysis. We show that CYP71D373 and CYP71D375 catalyze hydroxylation at carbon-16 (C16) and 14,16-ether (hetero)cyclization to form the D-ring, whereas CYP71D411 catalyzes upstream hydroxylation at C20. In addition, we discover a large biosynthetic gene cluster associated with tanshinone production. Collinearity analysis indicates a more specific origin of tanshinones in Salvia genus. It illustrates the evolutionary origin of abietane-type diterpenoids and those with a furan D-ring in Lamiaceae

On the wavelet transform in the field Qp of p-adic numbers

AbstractIn the present article we shall define the notion of the wavelet transform on Qp and we shall show that, for any given admissible function h∈L2(Qp), satisfying (15), which is a step function, the wavelet transform of a step function f be a function of norms, and moreover be expressible to a summation form

Linking endangered species protection to construct and optimize ecological security patterns in the National ecological Civilization construction Demonstration Zone: A case study of Yichang, China

Constructing an ecological security pattern (ESP) is an effective measure to ensure environmental safety and urban development. With the establishment of national ecological civilization construction demonstration zone in China, higher requirements are put forward for biodiversity conservation. Previous studies have focused on the identification and construction of ESPs, while few studies have optimized ESPs based on endangered species protection. This study took Yichang as the research object, and used geospatial data and endangered species data to construct and optimize ESPs. We identified ecological sources through ecological sensitivity assessment and extracted ecological corridors based on minimum cumulative resistance model. On this basis, this study innovatively introduced endangered species information, optimized an ESP and discussed ecological function zones in order to play a greater role in biodiversity conservation. The results showed that: (1) The ESP of Yichang includes 12 ecological sources with a total area of 2,186.34 km2, 30 ecological corridors with a total length of 1120.44 km and 15 ecological nodes. (2) The optimization of ESP connects important nature reserves and scenic tourist areas, bringing endangered species into the corridor network. The corridors importance evaluation delineated 8 Level I corridors focusing on biological protection and 22 Level II corridors focusing on landscape construction. (3) The ecological function zones of Yichang are divided into ecological conservation zone, ecological control zone and ecological restoration zone, and the spatial control principles of each zone are clearly defined. The results can provide a reference for biodiversity conservation in species-rich cities

Evaluating Sustainability of Tourism Projects in Rural Land Development Base on a Resilience Model

The underutilisation or overutilisation of various interdependent and interacting factors poses a challenge to sustainable development and requires the development of an appropriate methodology to evaluate the sustainability of tourism development projects in rural Land (TDPRL). However, most previous evaluations of TDPRL sustainability are macro-oriented and ignore the entire project life cycle. This study focuses on the resilience characteristics of TDPRL and proposes a “sustainable resilience model” based on physical-mechanical theory, which analyses various factors influencing TDPRL resilience based on the three dimensions of tractive force, driving force, and internal dynamic, and constructs a qualitative evaluation index system through stakeholder meetings. Then the analytic network process (ANP) is used to assess the resilience of TDPRL quantitatively. The rationality of the evaluation index system is validated through an empirical analysis of three rural tourism projects in Zhengzhou, Henan Province. We found that the resilience of TDPRL depends first on the project fundamentals, which include population, industry, location, and infrastructure. Second, local elites are crucial to rural tourism revitalization. Third, the project team should have sufficient capacity to provide tourists with satisfactory products and services, ensuring the project’s sustainable operation, and meeting the core demands of stakeholders. This study provides a novel tool for the decision-making and improvement of rural tourist project development and land use planning over the project life cycle

Evaluating Sustainability of Tourism Projects in Rural Land Development Base on a Resilience Model

The underutilisation or overutilisation of various interdependent and interacting factors poses a challenge to sustainable development and requires the development of an appropriate methodology to evaluate the sustainability of tourism development projects in rural Land (TDPRL). However, most previous evaluations of TDPRL sustainability are macro-oriented and ignore the entire project life cycle. This study focuses on the resilience characteristics of TDPRL and proposes a “sustainable resilience model” based on physical-mechanical theory, which analyses various factors influencing TDPRL resilience based on the three dimensions of tractive force, driving force, and internal dynamic, and constructs a qualitative evaluation index system through stakeholder meetings. Then the analytic network process (ANP) is used to assess the resilience of TDPRL quantitatively. The rationality of the evaluation index system is validated through an empirical analysis of three rural tourism projects in Zhengzhou, Henan Province. We found that the resilience of TDPRL depends first on the project fundamentals, which include population, industry, location, and infrastructure. Second, local elites are crucial to rural tourism revitalization. Third, the project team should have sufficient capacity to provide tourists with satisfactory products and services, ensuring the project’s sustainable operation, and meeting the core demands of stakeholders. This study provides a novel tool for the decision-making and improvement of rural tourist project development and land use planning over the project life cycle