Omics approaches have significantly increased our understanding of biological systems. However, they have had limited success in explaining the dramatically increased productivity of commercially ...important natural products by industrial high-producing strains, such as the erythromycin-producing actinomycete Saccharopolyspora erythraea. Further yield increase is of great importance but requires a better understanding of the underlying physiological processes.
To reveal the mechanisms related to erythromycin yield increase, we have undertaken an integrated study of the genomic, transcriptomic, and proteomic differences between the wild type strain NRRL2338 (WT) and the industrial high-producing strain ABE1441 (HP) of S. erythraea at multiple time points of a simulated industrial bioprocess. 165 observed mutations lead to differences in gene expression profiles and protein abundance between the two strains, which were most prominent in the initial stages of erythromycin production. Enzymes involved in erythromycin biosynthesis, metabolism of branched chain amino acids and proteolysis were most strongly upregulated in the HP strain. Interestingly, genes related to TCA cycle and DNA-repair were downregulated. Additionally, comprehensive data analysis uncovered significant correlations in expression profiles of the erythromycin-biosynthetic genes, other biosynthetic gene clusters and previously unidentified putative regulatory genes. Based on this information, we demonstrated that overexpression of several genes involved in amino acid metabolism can contribute to increased yield of erythromycin, confirming the validity of our systems biology approach.
Our comprehensive omics approach, carried out in industrially relevant conditions, enabled the identification of key pathways affecting erythromycin yield and suggests strategies for rapid increase in the production of secondary metabolites in industrial environment.
► Two mechanisms of internal oxidation in Ag–VC composite depend on the temperature of oxidation. ► The double oxide with low-melting points was observed. The rate
n is in accordance to parabolic ...law. ► The growth of oxide layers surrounding the carbide was observed at
T below the eutectic. ► The formation of liquid oxide pools was observed at temperature above the eutectic. ► The kinetic analysis indicates that oxidation at high temperature can be termed as catastrophic.
The internal oxidation (IO) of Ag–VC composites containing 5
vol.% of carbide was examined at three oxidation temperatures (350, 400, 600
°C). Two mechanisms were observed due to the formation of double oxides with relatively low-melting points. At temperatures below the lowest eutectic point
in situ, or diffusion less IO, was observed with the formation and growth of oxide layers surrounding the initial carbide. At temperatures above the eutectic point IO resulted in the formation of liquid oxide pools, which grew in size and developed into a network of oxides within the metal matrix. The kinetics confirmed the presence of two distinct mechanisms.
Sex life during pregnancy Košec, Tamara; Jug Došler, Anita; Kusterle, Mateja ...
Obzornik zdravstvene nege,
12/2019, Volume:
53, Issue:
4
Journal Article
Peer reviewed
Open access
Introduction: Pregnancy involves emotional and physiological changes, which affect the pregnant woman, her partner and their relationship. The sexuality of the couple changes with the onset of ...pregnancy compared to pre-pregnancy. The aim of the study was to investigate changes in the sex life of women during pregnancy.Methods: Quantitative research based on a questionnaire was carried out in August 2016 on a purposive sample of 685 women who had given birth at least once and women who were in the last trimester of pregnancy when completing the questionnaire. The data analysis included frequencies, percentages, mean values and independent samples t-test calculations.Results: The frequency of sexual intercourse decreased compared to the preconception period. The majority of women (43 %) included in the survey stated that their sexual desire declined during pregnancy. The most common factors that hindered women's sexual activity were fatigue and the feeling of awkwardness.Discussion and conclusion: Psychophysical changes in a pregnant woman may affect the couple's sexuality to a greater or lesser extent, which may in turn affect their relationship. It is therefore crucial that couples be offered quality counseling on sex life by appropriate institutions and programmes.
Erythromycin is a medically important antibiotic, biosynthesized by the actinomycete Saccharopolyspora erythraea. Genes encoding erythromycin biosynthesis are organized in a gene cluster, spanning ...over 60 kbp of DNA. Most often, gene clusters encoding biosynthesis of secondary metabolites contain regulatory genes. In contrast, the erythromycin gene cluster does not contain regulatory genes and regulation of its biosynthesis has therefore remained poorly understood, which has for a long time limited genetic engineering approaches for erythromycin yield improvement.
We used a comparative proteomic approach to screen for potential regulatory proteins involved in erythromycin biosynthesis. We have identified a putative regulatory protein SACE_5599 which shows significantly higher levels of expression in an erythromycin high-producing strain, compared to the wild type S. erythraea strain. SACE_5599 is a member of an uncharacterized family of putative regulatory genes, located in several actinomycete biosynthetic gene clusters. Importantly, increased expression of SACE_5599 was observed in the complex fermentation medium and at controlled bioprocess conditions, simulating a high-yield industrial fermentation process in the bioreactor. Inactivation of SACE_5599 in the high-producing strain significantly reduced erythromycin yield, in addition to drastically decreasing sporulation intensity of the SACE_5599-inactivated strains when cultivated on ABSM4 agar medium. In contrast, constitutive overexpression of SACE_5599 in the wild type NRRL23338 strain resulted in an increase of erythromycin yield by 32%. Similar yield increase was also observed when we overexpressed the bldD gene, a previously identified regulator of erythromycin biosynthesis, thereby for the first time revealing its potential for improving erythromycin biosynthesis.
SACE_5599 is the second putative regulatory gene to be identified in S. erythraea which has positive influence on erythromycin yield. Like bldD, SACE_5599 is involved in morphological development of S. erythraea, suggesting a very close relationship between secondary metabolite biosynthesis and morphological differentiation in this organism. While the mode of action of SACE_5599 remains to be elucidated, the manipulation of this gene clearly shows potential for improvement of erythromycin production in S. erythraea in industrial setting. We have also demonstrated the applicability of the comparative proteomics approach for identifying new regulatory elements involved in biosynthesis of secondary metabolites in industrial conditions.
Introduction: Pregnancy involves emotional and physiological changes, which affect the pregnant woman, her partner and their relationship. The sexuality of the couple changes with the onset of ...pregnancy compared to pre-pregnancy. The aim of the study was to investigate changes in the sex life of women during pregnancy. Methods: Quantitative research based on a questionnaire was carried out in August 2016 on a purposive sample of 685 women who had given birth at least once and women who were in the last trimester of pregnancy when completing the questionnaire. The data analysis included frequencies, percentages, mean values and independent samples t-test calculations. Results: The frequency of sexual intercourse decreased compared to the preconception period. The majority of women (43 %) included in the survey stated that their sexual desire declined during pregnancy. The most common factors that hindered women's sexual activity were fatigue and the feeling of awkwardness. Discussion and conclusion: Psychophysical changes in a pregnant woman may affect the couple's sexuality to a greater or lesser extent, which may in turn affect their relationship. It is therefore crucial that couples be offered quality counseling on sex life by appropriate institutions and programmes.
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