The fission yeast Schizosaccharomyces pombe has emerged as an attractive model organism in the recent years for the study of cytokinesis (Balasubramanian et al., 1997; Gould and Simanis, 1997; Le Goff et al., 1999a). Cell division in S. pombe is achieved through a medially positioned actomyosin ring structure, which is assembled at the onset of anaphase (Bahler et al., 1998). At the end of anap...

Yeast cells are non-motile and are encased in a cell wall that supports high internal turgor pressure. The cell wall is also essential for cellular morphogenesis and cell division. Here, we report unexpected morphogenetic changes in a Schizosaccharomyces pombe mutant defective in cell wall biogenesis. These cells form dynamic cytoplasmic protrusions caused by internal turgor pressure and also e...

FtsI (also called PBP3) of Escherichia coli is a transpeptidase required for synthesis of peptidoglycan in the division septum and is one of about a dozen division proteins that localize to the septal ring. FtsI comprises a short amino-terminal cytoplasmic domain, a single transmembrane helix (TMH), and a large periplasmic domain that encodes the catalytic (transpeptidase) activity. We show her...

We prove a Nullstellensatz for the ring of polynomial functions in n non-commuting variables over Hamilton's real quaternions. also characterize generalized identities which hold quaternions, and more generally, any division algebra .

Arithmetic in large ring and field extensions is an important problem of symbolic computation, and it consists essentially of the combination of one multiplication and one division in the underlying ring. Methods are known for replacing one division by two short multiplications in the underlying ring, which can be performed essentially by using convolutions. However, while using school-book mul...

E. coli cell division is mediated by the FtsZ ring and associated factors. Selection of the correct division site requires the combined action of an inhibitor of FtsZ ring formation (MinCD) and of a topological specificity factor that somehow prevents MinCD action at the middle of the cell (MinE). Here we show that a biologically active MinE-Gfp fusion accumulates in an annular structure near t...

Let S be a ring with identity in which 2 is invertible. In this paper we describe the structure of quaternion R = H(S) generalization Hamilton?s division real quaternions H H(R).

BACKGROUND Cell division in Bacillus subtilis takes place precisely at midcell, through the action of Noc, which prevents division from occurring over the nucleoids, and the Min system, which prevents cell division from taking place at the poles. Originally it was thought that the Min system acts directly on FtsZ, preventing the formation of a Z-ring and, therefore, the formation of a complete ...

Bacterial cell division typically requires assembly of the cytoskeletal protein FtsZ into a ring (Z-ring) at the nascent division site that serves as a foundation for assembly of the division apparatus. High resolution imaging suggests that the Z-ring consists of short, single-stranded polymers held together by lateral interactions. Several proteins implicated in stabilizing the Z-ring enhance ...