Plasticity in Cell Division Patterns and Auxin Transport Dependency during in Vitro Embryogenesis in Brassica napus

ABSTRACTGroup A streptococcus (GAS) is a human pathogen causing a wide repertoire of mild and severe diseases for which no vaccine is yet available. We recently reported the identification of three protein antigens that in combination conferred wide protection against GAS infection in mice. Here we focused our attention on the characterization of one of these three antigens, Spy0269, a highly conserved, surface-exposed, and immunogenic protein of unknown function. Deletion of thespy0269gene in a GAS M1 isolate resulted in very long bacterial chains, which is indicative of an impaired capacity of the knockout mutant to properly divide. Confocal microscopy and immunoprecipitation experiments demonstrated that the protein was mainly localized at the cell septum and could interactin vitrowith the cell division protein FtsZ, leading us to hypothesize that Spy0269 is a member of the GAS divisome machinery. Predicted structural domains and sequence homologies with known streptococcal adhesins suggested that this antigen could also play a role in mediating GAS interaction with host cells. This hypothesis was confirmed by showing that recombinant Spy0269 could bind to mammalian epithelial cellsin vitroand thatLactococcus lactisexpressing Spy0269 on its cell surface could adhere to mammalian cellsin vitroand to mice nasal mucosain vivo. On the basis of these data, we believe that Spy0269 is involved both in bacterial cell division and in adhesion to host cells and we propose to rename this multifunctional moonlighting protein as SpyAD (StreptococcuspyogenesAdhesion andDivision protein).

Download Full-text

Cytokinesis and Midzone Microtubule Organization inCaenorhabditis elegans Require the Kinesin-like Protein ZEN-4

Molecular Biology of the Cell ◽

10.1091/mbc.9.8.2037 ◽

1998 ◽

Vol 9 (8) ◽

pp. 2037-2049 ◽

Cited By ~ 193

Author(s):

William B. Raich ◽

Adrienne N. Moran ◽

Joel H. Rothman ◽

Jeff Hardin

Keyword(s):

Cell Division ◽

Null Allele ◽

Time Lapse ◽

Equatorial Region ◽

Microtubule Organization ◽

Dividing Cells ◽

Spindle Midzone ◽

Cross Links ◽

Complete Cell

Members of the MKLP1 subfamily of kinesin motor proteins localize to the equatorial region of the spindle midzone and are capable of bundling antiparallel microtubules in vitro. Despite these intriguing characteristics, it is unclear what role these kinesins play in dividing cells, particularly within the context of a developing embryo. Here, we report the identification of a null allele ofzen-4, an MKLP1 homologue in the nematodeCaenorhabditis elegans, and demonstrate that ZEN-4 is essential for cytokinesis. Embryos deprived of ZEN-4 form multinucleate single-celled embryos as they continue to cycle through mitosis but fail to complete cell division. Initiation of the cytokinetic furrow occurs at the normal time and place, but furrow propagation halts prematurely. Time-lapse recordings and microtubule staining reveal that the cytokinesis defect is preceded by the dissociation of the midzone microtubules. We show that ZEN-4 protein localizes to the spindle midzone during anaphase and persists at the midbody region throughout cytokinesis. We propose that ZEN-4 directly cross-links the midzone microtubules and suggest that these microtubules are required for the completion of cytokinesis.

Download Full-text

The in vitro toxicity of nitrile and epithionitrile derivatives of glucosinolates from swedes (Brassica napus) in human and bovine liver cells

New Zealand Veterinary Journal ◽

10.1080/00480169.2021.1875933 ◽

2021 ◽

pp. 1-9

Author(s):

I Latimer ◽

R Chand ◽

B Cridge

Keyword(s):

Brassica Napus ◽

Bovine Liver ◽

Liver Cells ◽

In Vitro Toxicity ◽

Derivatives Of

Download Full-text

Modification of cell division by phorbol ester in preimplantation mouse embryos

Development ◽

10.1242/dev.101.2.403 ◽

1987 ◽

Vol 101 (2) ◽

pp. 403-408

Author(s):

E.T. Mystkowska ◽

W. Sawicki

Keyword(s):

Cell Division ◽

Video Recording ◽

Mouse Embryos ◽

Time Intervals ◽

Cell Divisions ◽

Stage Of Development ◽

Preimplantation Mouse Embryos ◽

Preimplantation Mouse ◽

Single Blastomeres

2-cell mouse embryos were treated in vitro with a 2 h pulse of phorbol myristate acetate (PMA) at 32nd, 38th and 50th h after hCG, then chased in culture for up to 46 h. Embryos were fixed at various time intervals of chasing, then stained and inspected. Some embryos were carefully inspected with a video recording system, every 1.44s and the cell divisions (cytokinesis) as well as formation of large, single blastomeres, each from two smaller ones, were recorded. PMA pulse let to the suppression of cell divisions. The rate of the suppression was time dependent: with a delay of 0–1, 12 and 18 h between the PMA pulse and time of scheduled cell division about 99, 87 and 44% of 2-cell embryos remained at this stage of development, for at least 10 h, respectively, and 90, 58 and 12% of their blastomeres revealed binuclearity. Since we found that PMA-mediated formation of binuclearity was not the effect of cell fusions, it was assumed that the inhibition of cytokinesis preceded by karyokinesis was responsible for binuclearity. PMA effect on cell divisions was reversible. PMA-treated embryos revealed formation of large, single blastomeres, each from two smaller ones. If cell division appeared after PMA pulse, in about 52% of 3- to 6-cell embryos, the large blastomere formation was recorded in the course of the subsequent 38 h. Large blastomere formation was concluded to be the result of either cell fusion or reversion of incompleted cytokinesis brought about by PMA.

Download Full-text