scholarly journals Novobiocin inhibits membrane synthesis and vacuole formation of Enterococcus faecalis protoplasts

2020 ◽  
Vol 7 (11) ◽  
pp. 300-308
Author(s):  
Rintaro Tsuchikado ◽  
Satoshi Kami ◽  
Sawako Takahashi ◽  
Hiromi Nishida

We demonstrate that plasma membrane biosynthesis and vacuole formation require DNA replication in Enterococcus faecalis protoplasts. The replication inhibitor novobiocin inhibited not only DNA replication but also cell enlargement (plasma membrane biosynthesis) and vacuole formation during the enlargement of the E. faecalis protoplasts. After novobiocin treatment prior to vacuole formation, the cell size of E. faecalis protoplasts was limited to 6 μm in diameter and the cells lacked vacuoles. When novobiocin was added after vacuole formation, E. faecalis protoplasts grew with vacuole enlargement; after novobiocin removal, protoplasts were enlarged again. Although cell size distribution of the protoplasts was similar following the 24 h and 48 h novobiocin treatments, after 72 h of novobiocin treatment there was a greater number of smaller sized protoplasts, suggesting that extended novobiocin treatment may inhibit the re-enlargement of E. faecalis protoplasts after novobiocin removal. Our findings demonstrate that novobiocin can control the enlargement of E. faecalis protoplasts due to inhibition of DNA replication.

Author(s):  
Zsuzsanna Márton ◽  
Bianka Csitári ◽  
Tamas Felfoldi ◽  
Anna J Szekely ◽  
Attila Szabo

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 713-723
Author(s):  
Wei Gong ◽  
Tuan-Hui Jiang ◽  
Xiang-Bu Zeng ◽  
Li He ◽  
Chun Zhang

AbstractThe effects of the cell size and distribution on the mechanical properties of polypropylene foam were simulated and analyzed by finite element modeling with ANSYS and supporting experiments. The results show that the reduced cell size and narrow size distribution have beneficial influences on both the tensile and impact strengths. Decreasing the cell size or narrowing the cell size distribution was more effective for increasing the impact strength than the tensile strength in the same case. The relationship between the mechanical properties and cell structure parameters has a good correlation with the theoretical model.


2014 ◽  
Vol 13 (2) ◽  
pp. 259-268 ◽  
Author(s):  
Anna Czerednik ◽  
Marco Busscher ◽  
Gerco C. Angenent ◽  
Ruud A. de Maagd

1973 ◽  
Vol 30 (2) ◽  
pp. 143-155 ◽  
Author(s):  
A. Prakash ◽  
Liv Skoglund ◽  
Britt Rystad ◽  
Arne Jensen

An extended exponential growth phase and a higher maximum population characterized growth of planktonic algae in a dialysis system compared with that in a batch system. Algal cells grown in a dialysis culture had higher chlorophyll content and a larger average cell size than those grown in a batch culture. In both types of culture, changes in cell-size distribution were related to the phases of the growth cycle with maximum cell-size during the stationary phase. Various interactions of the component reactions of photosynthesis leading to changes in growth pattern and cell-size distribution are discussed.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sawako Takahashi ◽  
Marin Mizuma ◽  
Satoshi Kami ◽  
Hiromi Nishida

Abstract Vacuole generation occurs frequently during the enlargement of bacterial protoplasts and spheroplasts. Gram-positive Enterococcus faecalis protoplasts and gram-negative Lelliottia amnigena spheroplasts had large and small vacuoles inside the cytoplasm, respectively. Although no vacuoles were found at the early stage of cell enlargement, all enlarged cells used in the microinjection procedures had vacuoles. The plasma membrane of L. amnigena was more flexible than that of E. faecalis. In addition, E. faecalis protoplasts had unique discoidal structures as well as spherical structures in the cytoplasm. Our findings showed that the number of vacuoles increased as the L. amnigena plasma membrane expanded and that the size of vacuoles increased as the E. faecalis plasma membrane expanded, suggesting that bacterial cell enlargement involved vacuole generation. Thus, biosynthesis of the plasma and vacuolar membranes was synchronous with the bacterial cell enlargement. Differences in the plasma membrane flexibility might influence the different types of vacuole generation.


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