title: Distension of the toga of Thermotoga maritima involves continued growth of the outer envelope as cells enter the stationary phase.
abstract: Thermotoga maritima cells are distinguished by a sheath-like structure called the toga that loosely encloses single or multiple cells. During growth, and particularly at late phases of population growth, the toga distends from the poles of many cells. Little is known about this phenomenon so this study presents basic information about this process. We first provide quantitative data demonstrating that cells showing toga distensions increase in number during growth and that the phenomenon is not due to acidification of their growth medium. Comparisons of the area enclosed by these distended togas to the area of the cytoplasm show that the toga continues to grow as the growth of the cytoplasm ceases. Measuring the expression of many genes involved in toga composition and biosynthesis showed a 5.2-, 7.9- and 3-fold increase in the expression of toga structural protein genes ompB (porin), ompA1 and ompA2 (alpha helical, transperiplasm anchors), respectively. Additionally, expression of the putative pyruvyl transferase gene (csaB) was upregulated 4.4-fold in stationary phase, while the beta barrel assembly factor gene (bamA) showed only a 1.2-fold increase in expression. These findings demonstrate that toga distension is an active process and one that needs further investigation so we can understand the selective forces that operate in high-temperature environments.
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Chaman
authors.initials: C
authors.lastname: Ranjit
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA kenneth.noll@uconn.edu.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Noll
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002462:Cell Membrane / Q000235:genetics / Q000502:physiology*; D002473:Cell Wall / Q000235:genetics / Q000502:physiology; D003470:Culture Media / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D006358:Hot Temperature; D018272:Porins / Q000235:genetics; D020124:Thermotoga maritima / Q000166:cytology* / Q000254:growth & development*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D003470:Culture Media; D018272:Porins; C078167:OMPA outer membrane proteins
keywords: Thermotoga; cell wall; outer envelope; thermophile