The expression of genes for S-adenosylmethionine synthetase (SAMS), which catalyzes the synthesis of S-adenosylmethionine (AdoMet), a major methyl donor in cells, was studied in symbiont-free (D) and symbiont-bearing (xD) amoeba strains to determine the effect of bacterial endosymbionts. The symbionts suppressed the expression of the gene in host xD amoebae, but amoebae still exhibited about half the enzyme activity found in symbiont-free D amoebae. The study was aimed at elucidating mechanisms of the suppression of the amoeba's gene and determining the alternative source for the gene product. Unexpectedly, we found a second sams (sams2) gene in amoebae, which encoded 390 amino acids. Results of experiments measuring SAMS activities and amounts of AdoMet in D and xD amoebae showed that the half SAMS activity found in xD amoebae came from the amoeba's SAMS2 and not from their endosymbionts. The expression of amoeba sams genes was switched from sams1 to sams2 as a result of infection with X-bacteria, raising the possibility that the switch in the expression of sams genes by bacteria plays a role in the development of symbiosis and the host-pathogen interactions. This is the first report showing such a switch in the expression of host sams genes by infecting bacteria.
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http://dx.doi.org/10.1242/jcs.00894 | DOI Listing |
Med Microbiol Immunol
January 2025
Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
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View Article and Find Full Text PDFFront Plant Sci
November 2024
Department of Agronomy, Hetao College, Bayannur, China.
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Eur J Appl Physiol
November 2024
Institute of Sport Science, Universität of Innsbruck, 6020, Innsbruck, Austria.
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View Article and Find Full Text PDFSci Total Environ
December 2024
Departamento de Ciencias del Mar y Biología Aplicada, Universidad de Alicante, Alicante, Spain; Laboratory of Aquatic Environmental Research, HUB AMBIENTAL UPLA, Universidad de Playa Ancha, Valparaíso, Chile; Departamento de Ciencias y Geografía, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, Chile. Electronic address:
Seagrasses have adapted to a submerged lifestyle in seawater through a complex set of evolutionary processes. However, they show sensitivity to increases in natural salinity levels such as those commonly found in discharges of desalination plants, which have exponentially grown due to water scarcity in highly populated temperate areas, such as the Mediterranean basin. This study assessed the effects of brine-derived hypersalinity on the Mediterranean seagrass Posidonia oceanica, focusing on the metabolic responses of shoot apical meristems (SAMs).
View Article and Find Full Text PDFArch Immunol Ther Exp (Warsz)
January 2024
Medical College, South China University of Technology, Guangzhou, China.
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