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Advances in technologies that permit high-resolution analysis of events in single cells have revealed that phenotypic heterogeneity is a widespread phenomenon in bacteria. Flow cytometry has the potential to describe the distribution of cellular properties within a population of bacterial cells and has yielded invaluable information about the ability of isogenic cells to diversify into phenotypic subpopulations. This review will discuss several single-cell approaches that have recently been applied to define phenotypic heterogeneity in populations of Salmonella enterica.

14 páginas.- 6 figuras.- 2 tablas.- referencias.- The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb.2021.647305/full#supplementary-material, Genes annotated as ygfE and yiiU in the genome of Salmonella enterica serovar Typhimurium encode proteins homologous to Escherichia coli cell division factors ZapA and ZapB, respectively. ZapA− and ZapB− mutants of S. enterica are bile-sensitive. The amount of zapB mRNA increases in the presence of a sublethal concentration of sodium deoxycholate (DOC) while zapA mRNA remains unaffected. Increased zapB mRNA level in the presence of DOC is not caused by upregulation of zapB transcription but by increased stability of zapB mRNA. This increase is suppressed by an hfq mutation, suggesting the involvement of a small regulatory RNA. We provide evidence that such sRNA is MicA. The ZapB protein is degraded in the presence of DOC, and degradation appears to involve the Lon protease. We propose that increased stability of zapB mRNA in the presence of DOC may counter degradation of bile-damaged ZapB, thereby providing sufficient level of functional ZapB protein to permit Z-ring assembly in the presence of bile, This study was supported by grant BIO2016-75235-P from the Spanish Ministerio de Economía, Industria y Competitividad - Agencia Estatal de Investigación and the European Regional Fund. VU was supported by a postdoctoral contract associated to grant CVI-5879 from the Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía, Spain. MS-R was supported by the VI Plan Propio de Investigación y Transferencia de la Universidad de Sevilla.

A gene annotated asyiiUin the genome ofSalmonella entericaserovar Typhimurium encodes a protein homologous toE. coliZapB, a non-essential cell division factor involved in Z-ring assembly. ZapB−null mutants ofS. entericaare bile-sensitive. The ZapB protein is degraded in the presence of sodium deoxycholate (DOC), and degradation appears to involve the Lon protease. The amount ofzapBmRNA increases in the presence of a sublethal concentration of DOC. This increase is not caused by upregulation ofzapBtranscription but by increased stability ofzapBmRNA. DOC-induced increase of thezapBtranscript is suppressed by anhfqmutation, suggesting the involvement of a small regulatory RNA. We provide evidence that such sRNA is MicA. Increased stability ofzapBmRNA in the presence of DOC may counter degradation of bile-damaged ZapB, thus providing sufficient level of functional ZapB protein to permit Z-ring assembly in the presence of bile.IMPORTANCEBile salts have bactericidal activity as a consequence of membrane disruption, protein denaturation and DNA damage. However, intestinal bacteria are resistant to bile. Envelope structures such as the lipopolysaccharide and the enterobacterial common antigen act as barriers that reduce intake of bile salts. Remodelling of the outer membrane and the peptidoglycan, activation of efflux pumps, and upregulation of stress responses also contribute to bile resistance. This study adds the cell division factor ZapB (and presumably the Z-ring) to the list of cellular functions involved in bile resistance.

Background The place of monoclonal antibodies in metastatic colorectal cancer has not been clearly defined. Objective To determine the treatment pattern of monoclonal antibodies in colorectal cancer patients in the Andalusian Public Healthcare System. Method Data were collected from all patients treated with these drugs from July 2009 to December 2010 from pharmacy programs and medical records. Results Three hundred patients were included, of whom 227 received the antibody at the forefront. The proportion of patients who received bevacizumab in the first line is greater than that of cetuximab (62.1 vs. 37.5 % respectively) and similar in the second line and subsequent (47.8 vs. 53.8 % and 48.5 vs. 46.2 % respectively). XELOXbevacizumab was the most frequently prescribed scheme (35.3 %) followed by FOLFOX-monoclonal antibody schemes, regardless that this was bevacizumab or cetuximab (22.5 %). The median progression free survival (PFS) was 11.7 months for patients receiving cetuximab, 9.6 months for patients receiving bevacizumab and 8.2 months for those who received no monoclonal antibody in the first line. Conclusion Bevacizumab was the antibody of choice in first line, showing utilization rates similar to cetuximab in second line and subsequent. The median PFS in our study is related to the PFS of the major clinical trials.