Filamentation

Last updated
A Bacillus cereus cell that has undergone filamentation following antibacterial treatment (upper electron micrograph; top right) and regularly sized cells of untreated B. cereus (lower electron micrograph) Filamentation 2.jpg
A Bacillus cereus cell that has undergone filamentation following antibacterial treatment (upper electron micrograph; top right) and regularly sized cells of untreated B. cereus (lower electron micrograph)

Filamentation is the anomalous growth of certain bacteria, such as Escherichia coli , in which cells continue to elongate but do not divide (no septa formation). [1] [2] The cells that result from elongation without division have multiple chromosomal copies. [1]

Contents

In the absence of antibiotics or other stressors, filamentation occurs at a low frequency in bacterial populations (4–8% short filaments and 0–5% long filaments in 1- to 8-hour cultures). [3] The increased cell length can protect bacteria from protozoan predation and neutrophil phagocytosis by making ingestion of cells more difficult. [1] [3] [4] [5] Filamentation is also thought to protect bacteria from antibiotics, and is associated with other aspects of bacterial virulence such as biofilm formation. [6] [7]

The number and length of filaments within a bacterial population increases when the bacteria are exposed to different physical, chemical and biological agents (e.g. UV light, DNA synthesis-inhibiting antibiotics, bacteriophages). [3] [8] This is termed conditional filamentation. [2] Some of the key genes involved in filamentation in E. coli include sulA, minCD and damX. [9] [10]

Filament formation

Antibiotic-induced filamentation

Some peptidoglycan synthesis inhibitors (e.g. cefuroxime, ceftazidime) induce filamentation by inhibiting the penicillin binding proteins (PBPs) responsible for crosslinking peptidoglycan at the septal wall (e.g. PBP3 in E. coli and P. aeruginosa). Because the PBPs responsible for lateral wall synthesis are relatively unaffected by cefuroxime and ceftazidime, cell elongation proceeds without any cell division and filamentation is observed. [3] [11] [12]

DNA synthesis-inhibiting and DNA damaging antibiotics (e.g. metronidazole, mitomycin C, the fluoroquinolones, novobiocin) induce filamentation via the SOS response. The SOS response inhibits septum formation until the DNA can be repaired, this delay stopping the transmission of damaged DNA to progeny. Bacteria inhibit septation by synthesizing protein SulA, an FtsZ inhibitor that halts Z-ring formation, thereby stopping recruitment and activation of PBP3. [3] [13] If bacteria are deprived of the nucleobase thymine by treatment with folic acid synthesis inhibitors (e.g. trimethoprim), this also disrupts DNA synthesis and induces SOS-mediated filamentation. Direct obstruction of Z-ring formation by SulA and other FtsZ inhibitors (e.g. berberine) induces filamentation too. [3] [14] [15]

Some protein synthesis inhibitors (e.g. kanamycin), RNA synthesis inhibitors (e.g. bicyclomycin) and membrane disruptors (e.g. daptomycin, polymyxin B) cause filamentation too, but these filaments are much shorter than the filaments induced by the above antibiotics. [3]

Stress-induced filamentation

Filamentation is often a consequence of environmental stress. It has been observed in response to temperature shocks, [16] low water availability, [17] high osmolarity, [18] extreme pH, [19] and UV exposure. [20] UV light damages bacterial DNA and induces filamentation via the SOS response. [3] [21] Starvation can also cause bacterial filamentation. [9] For example, if bacteria are deprived of the nucleobase thymine, this disrupts DNA synthesis and induces SOS-mediated filamentation. [3] [22]

Nutrient-induced filamentation

Several macronutrients and biomolecules can cause bacterial cells to filament, including the amino acids glutamine, proline and arginine, and some branched-chain amino acids. [23] Certain bacterial species, such as Paraburkholderia elongata , will also filament as a result of a tendency to accumulate phosphate in the form of polyphosphate, which can chelate metal cofactors needed by division proteins. [2] In addition, filamentation is induced by nutrient-rich conditions in the intracellular pathogen Bordetella atropi . This occurs via the highly conserved UDP-glucose pathway. UDP-glucose biosynthesis and sensing suppresses bacterial cell division, with the ensuing filamentation allowing B. atropi to spread to neighboring cells. [24]

Intrinsic dysbiosis-induced filamentation

Filamentation can also be induced by other pathways affecting thymidylate synthesis. For instance, partial loss of dihydrofolate reductase (DHFR) activity causes reversible filamentation. [25] DHFR has a critical role in regulating the amount of tetrahydrofolate, which is essential for purine and thymidylate synthesis. DHFR activity can be inhibited by mutations or by high concentrations of the antibiotic trimethoprim (see antibiotic-induced filamentation above).

Overcrowding of the periplasm or envelope can also induce filamentation in Gram-negative bacteria by disrupting normal divisome function. [26] [27]

Filamentation and biotic interactions

Several examples of filamentation that result from biotic interactions between bacteria and other organisms or infectious agents have been reported. Filamentous cells are resistant to ingestion by bacterivores, and environmental conditions generated during predation can trigger filamentation. [28] Filamentation can also be induced by signalling factors produced by other bacteria. [29] In addition, Agrobacterium spp. filament in proximity to plant roots, [30] and E. coli filaments when exposed to plant extracts. [31] Lastly, bacteriophage infection can result in filamentation via the expression of proteins that inhibit divisome assembly. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Pilus</span> A proteinaceous hair-like appendage on the surface of bacteria

A pilus is a hair-like appendage found on the surface of many bacteria and archaea. The terms pilus and fimbria can be used interchangeably, although some researchers reserve the term pilus for the appendage required for bacterial conjugation. All conjugative pili are primarily composed of pilin – fibrous proteins, which are oligomeric.

A spheroplast is a microbial cell from which the cell wall has been almost completely removed, as by the action of penicillin or lysozyme. According to some definitions, the term is used to describe Gram-negative bacteria. According to other definitions, the term also encompasses yeasts. The name spheroplast stems from the fact that after the microbe's cell wall is digested, membrane tension causes the cell to acquire a characteristic spherical shape. Spheroplasts are osmotically fragile, and will lyse if transferred to a hypotonic solution.

<span class="mw-page-title-main">FtsZ</span> Protein encoded by the ftsZ gene

FtsZ is a protein encoded by the ftsZ gene that assembles into a ring at the future site of bacterial cell division. FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamenting temperature-sensitive mutant Z." The hypothesis was that cell division mutants of E. coli would grow as filaments due to the inability of the daughter cells to separate from one another. FtsZ is found in almost all bacteria, many archaea, all chloroplasts and some mitochondria, where it is essential for cell division. FtsZ assembles the cytoskeletal scaffold of the Z ring that, along with additional proteins, constricts to divide the cell in two.

<span class="mw-page-title-main">SOS response</span> Biological process

The SOS response is a global response to DNA damage in which the cell cycle is arrested and DNA repair and mutagenesis is induced. The system involves the RecA protein. The RecA protein, stimulated by single-stranded DNA, is involved in the inactivation of the repressor (LexA) of SOS response genes thereby inducing the response. It is an error-prone repair system that contributes significantly to DNA changes observed in a wide range of species.

<span class="mw-page-title-main">Nucleoid</span> Region within a prokaryotic cell containing genetic material

The nucleoid is an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material. The chromosome of a typical prokaryote is circular, and its length is very large compared to the cell dimensions, so it needs to be compacted in order to fit. In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane. Instead, the nucleoid forms by condensation and functional arrangement with the help of chromosomal architectural proteins and RNA molecules as well as DNA supercoiling. The length of a genome widely varies and a cell may contain multiple copies of it.

<span class="mw-page-title-main">RecA</span> DNA repair protein

RecA is a 38 kilodalton protein essential for the repair and maintenance of DNA. A RecA structural and functional homolog has been found in every species in which one has been seriously sought and serves as an archetype for this class of homologous DNA repair proteins. The homologous protein is called RAD51 in eukaryotes and RadA in archaea.

<span class="mw-page-title-main">Penicillin-binding proteins</span> Class of proteins

Penicillin-binding proteins (PBPs) are a group of proteins that are characterized by their affinity for and binding of penicillin. They are a normal constituent of many bacteria; the name just reflects the way by which the protein was discovered. All β-lactam antibiotics bind to PBPs, which are essential for bacterial cell wall synthesis. PBPs are members of a subgroup of enzymes called transpeptidases. Specifically, PBPs are DD-transpeptidases.

<span class="mw-page-title-main">Efflux (microbiology)</span> Protein complexes that move compounds, generally toxic, out of bacterial cells

In microbiology, efflux is the moving of a variety of different compounds out of cells, such as antibiotics, heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals, bacterial metabolites and neurotransmitters. All microorganisms, with a few exceptions, have highly conserved DNA sequences in their genome that encode efflux pumps. Efflux pumps actively move substances out of a microorganism, in a process known as active efflux, which is a vital part of xenobiotic metabolism. This active efflux mechanism is responsible for various types of resistance to bacterial pathogens within bacterial species - the most concerning being antibiotic resistance because microorganisms can have adapted efflux pumps to divert toxins out of the cytoplasm and into extracellular media.

<span class="mw-page-title-main">Guanosine pentaphosphate</span> Chemical compound

(p)ppGpp, guanosine pentaphosphate and tetraphosphate, also known as the "magic spot" nucleotides, are alarmones involved in the stringent response in bacteria that cause the inhibition of RNA synthesis when there is a shortage of amino acids. This inhibition by (p)ppGpp decreases translation in the cell, conserving amino acids present. Furthermore, ppGpp and pppGpp cause the up-regulation of many other genes involved in stress response such as the genes for amino acid uptake and biosynthesis.

<span class="mw-page-title-main">Evelyn M. Witkin</span> American geneticist (1921–2023)

Evelyn M. Witkin was an American bacterial geneticist at Cold Spring Harbor Laboratory (1944–1955), SUNY Downstate Medical Center (1955–1971), and Rutgers University (1971–1991). Witkin was considered innovative and inspirational as a scientist, teacher and mentor.

<span class="mw-page-title-main">Prokaryotic cytoskeleton</span> Structural filaments in prokaryotes

The prokaryotic cytoskeleton is the collective name for all structural filaments in prokaryotes. It was once thought that prokaryotic cells did not possess cytoskeletons, but advances in visualization technology and structure determination led to the discovery of filaments in these cells in the early 1990s. Not only have analogues for all major cytoskeletal proteins in eukaryotes been found in prokaryotes, cytoskeletal proteins with no known eukaryotic homologues have also been discovered. Cytoskeletal elements play essential roles in cell division, protection, shape determination, and polarity determination in various prokaryotes.

mecA is a gene found in bacterial cells which allows them to be resistant to antibiotics such as methicillin, penicillin and other penicillin-like antibiotics.

Persister cells are subpopulations of cells that resist treatment, and become antimicrobial tolerant by changing to a state of dormancy or quiescence. Persister cells in their dormancy do not divide. The tolerance shown in persister cells differs from antimicrobial resistance in that the tolerance is not inherited and is reversible. When treatment has stopped the state of dormancy can be reversed and the cells can reactivate and multiply. Most persister cells are bacterial, and there are also fungal persister cells, yeast persister cells, and cancer persister cells that show tolerance for cancer drugs.

<span class="mw-page-title-main">Toxin-antitoxin system</span> Biological process

A toxin-antitoxin system consists of a "toxin" and a corresponding "antitoxin", usually encoded by closely linked genes. The toxin is usually a protein while the antitoxin can be a protein or an RNA. Toxin-antitoxin systems are widely distributed in prokaryotes, and organisms often have them in multiple copies. When these systems are contained on plasmids – transferable genetic elements – they ensure that only the daughter cells that inherit the plasmid survive after cell division. If the plasmid is absent in a daughter cell, the unstable antitoxin is degraded and the stable toxic protein kills the new cell; this is known as 'post-segregational killing' (PSK).

Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.

DNA Polymerase V is a polymerase enzyme involved in DNA repair mechanisms in bacteria, such as Escherichia coli. It is composed of a UmuD' homodimer and a UmuC monomer, forming the UmuD'2C protein complex. It is part of the Y-family of DNA Polymerases, which are capable of performing DNA translesion synthesis (TLS). Translesion polymerases bypass DNA damage lesions during DNA replication - if a lesion is not repaired or bypassed the replication fork can stall and lead to cell death. However, Y polymerases have low sequence fidelity during replication. When the UmuC and UmuD' proteins were initially discovered in E. coli, they were thought to be agents that inhibit faithful DNA replication and caused DNA synthesis to have high mutation rates after exposure to UV-light. The polymerase function of Pol V was not discovered until the late 1990s when UmuC was successfully extracted, consequent experiments unequivocally proved UmuD'2C is a polymerase. This finding lead to the detection of many Pol V orthologs and the discovery of the Y-family of polymerases.

<span class="mw-page-title-main">FtsA</span> Bacterial protein that is related to actin

FtsA is a bacterial protein that is related to actin by overall structural similarity and in its ATP binding pocket.

<span class="mw-page-title-main">Divisome</span> A protein complex in bacteria responsible for cell division

The divisome is a protein complex in bacteria that is responsible for cell division, constriction of inner and outer membranes during division, and peptidoglycan (PG) synthesis at the division site. The divisome is a membrane protein complex with proteins on both sides of the cytoplasmic membrane. In gram-negative cells it is located in the inner membrane. The divisome is nearly ubiquitous in bacteria although its composition may vary between species.

<span class="mw-page-title-main">FtsK</span> Protein involved in bacterial cell division

FtsK, discovered in 1995 by the Donachie lab, is one of the largest proteins in E. coli at 1329 amino acids. It is involved in bacterial cell division and chromosome segregation. FtsK stands for "Filament temperature sensitive mutant K" because cells expressing a mutant ftsK allele called ftsK44, which encodes an FtsK variant containing an G80A residue change in the second transmembrane segment, fail to divide at high temperatures and form long filaments instead. FtsK, specifically its C-terminal domain, functions as a DNA translocase, interacts with other cell division proteins, and regulates Xer-mediated recombination. FtsK belongs to the AAA superfamily and is present in most bacteria.

A. C. Matin is an Indian-American microbiologist, immunologist, academician and researcher. He is a professor of microbiology and immunology at Stanford University School of Medicine.

References

  1. 1 2 3 Jaimes-Lizcano YA, Hunn DD, Papadopoulos KD (April 2014). "Filamentous Escherichia coli cells swimming in tapered microcapillaries". Research in Microbiology. 165 (3): 166–74. doi:10.1016/j.resmic.2014.01.007. PMID   24566556.
  2. 1 2 3 Karasz DC, Weaver AI, Buckley DH, Wilhelm RC (January 2022). "Conditional filamentation as an adaptive trait of bacteria and its ecological significance in soils". Environmental Microbiology. 24 (1): 1–17. doi:10.1111/1462-2920.15871. OSTI   1863903. PMID   34929753. S2CID   245412965.
  3. 1 2 3 4 5 6 7 8 9 Cushnie TP, O'Driscoll NH, Lamb AJ (December 2016). "Morphological and ultrastructural changes in bacterial cells as an indicator of antibacterial mechanism of action". Cellular and Molecular Life Sciences. 73 (23): 4471–4492. doi:10.1007/s00018-016-2302-2. hdl: 10059/2129 . PMID   27392605. S2CID   2065821.
  4. Hahn MW, Höfle MG (May 1998). "Grazing pressure by a bacterivorous flagellate reverses the relative abundance of Comamonas acidovorans PX54 and Vibrio strain CB5 in chemostat cocultures". Applied and Environmental Microbiology. 64 (5): 1910–8. Bibcode:1998ApEnM..64.1910H. doi:10.1128/AEM.64.5.1910-1918.1998. PMC   106250 . PMID   9572971.
  5. Hahn MW, Moore ER, Höfle MG (January 1999). "Bacterial filament formation, a defense mechanism against flagellate grazing, is growth rate controlled in bacteria of different phyla". Applied and Environmental Microbiology. 65 (1): 25–35. Bibcode:1999ApEnM..65...25H. doi:10.1128/AEM.65.1.25-35.1999. PMC   90978 . PMID   9872755.
  6. Justice SS, Hunstad DA, Cegelski L, Hultgren SJ (February 2008). "Morphological plasticity as a bacterial survival strategy". Nature Reviews. Microbiology. 6 (2): 162–8. doi:10.1038/nrmicro1820. PMID   18157153. S2CID   7247384.
  7. Fuchs BB, Eby J, Nobile CJ, El Khoury JB, Mitchell AP, Mylonakis E (June 2010). "Role of filamentation in Galleria mellonella killing by Candida albicans". Microbes and Infection. 12 (6): 488–96. doi:10.1016/j.micinf.2010.03.001. PMC   288367 . PMID   20223293.
  8. 1 2 Ragunathan PT, Vanderpool CK (December 2019). "Cryptic-Prophage-Encoded Small Protein DicB Protects Escherichia coli from Phage Infection by Inhibiting Inner Membrane Receptor Proteins". Journal of Bacteriology. 201 (23). doi:10.1128/JB.00475-19. PMC   6832061 . PMID   31527115.
  9. 1 2 Bi E, Lutkenhaus J (February 1993). "Cell division inhibitors SulA and MinCD prevent formation of the FtsZ ring". Journal of Bacteriology. 175 (4): 1118–1125. doi: 10.1128/jb.175.4.1118-1125.1993 . PMC   193028 . PMID   8432706.
  10. Khandige S, Asferg CA, Rasmussen KJ, Larsen MJ, Overgaard M, Andersen TE, Møller-Jensen J (August 2016). Justice S, Hultgren SJ (eds.). "DamX Controls Reversible Cell Morphology Switching in Uropathogenic Escherichia coli". mBio. 7 (4). doi:10.1128/mBio.00642-16. PMC   4981707 . PMID   27486187.
  11. Spratt BG (August 1975). "Distinct penicillin binding proteins involved in the division, elongation, and shape of Escherichia coli K12". Proceedings of the National Academy of Sciences of the United States of America. 72 (8): 2999–3003. Bibcode:1975PNAS...72.2999S. doi: 10.1073/pnas.72.8.2999 . PMC   432906 . PMID   1103132.
  12. Bush K, Bradford PA (August 2016). "β-Lactams and β-Lactamase Inhibitors: An Overview". Cold Spring Harbor Perspectives in Medicine. 6 (8): a025247. doi:10.1101/cshperspect.a025247. PMC   4968164 . PMID   27329032.
  13. Cordell SC, Robinson EJ, Lowe J (June 2003). "Crystal structure of the SOS cell division inhibitor SulA and in complex with FtsZ". Proceedings of the National Academy of Sciences of the United States of America. 100 (13): 7889–94. Bibcode:2003PNAS..100.7889C. doi: 10.1073/pnas.1330742100 . PMC   164683 . PMID   12808143.
  14. Ray S, Dhaked HP, Panda D (October 2014). "Antimicrobial peptide CRAMP (16-33) stalls bacterial cytokinesis by inhibiting FtsZ assembly". Biochemistry. 53 (41): 6426–9. doi:10.1021/bi501115p. PMID   25294259.
  15. Sass P, Brötz-Oesterhelt H (October 2013). "Bacterial cell division as a target for new antibiotics". Current Opinion in Microbiology. 16 (5): 522–530. doi:10.1016/j.mib.2013.07.006. PMID   23932516.
  16. Gill CO, Badoni M, Jones TH (November 2007). "Behaviours of log phase cultures of eight strains of Escherichia coli incubated at temperatures of 2, 6, 8 and 10 degrees C". International Journal of Food Microbiology. 119 (3): 200–206. doi:10.1016/j.ijfoodmicro.2007.07.043. PMID   17719669.
  17. Mattick KL, Jørgensen F, Legan JD, Cole MB, Porter J, Lappin-Scott HM, Humphrey TJ (April 2000). "Survival and filamentation of Salmonella enterica serovar enteritidis PT4 and Salmonella enterica serovar typhimurium DT104 at low water activity". Applied and Environmental Microbiology. 66 (4): 1274–1279. Bibcode:2000ApEnM..66.1274M. doi:10.1128/AEM.66.4.1274-1279.2000. PMC   91980 . PMID   10742199.
  18. Chang WS, Halverson LJ (October 2003). "Reduced water availability influences the dynamics, development, and ultrastructural properties of Pseudomonas putida biofilms". Journal of Bacteriology. 185 (20): 6199–6204. doi:10.1128/JB.185.20.6199-6204.2003. PMC   225025 . PMID   14526033.
  19. Jones TH, Vail KM, McMullen LM (July 2013). "Filament formation by foodborne bacteria under sublethal stress". International Journal of Food Microbiology. 165 (2): 97–110. doi:10.1016/j.ijfoodmicro.2013.05.001. PMID   23727653.
  20. Modenutti B, Balseiro E, Corno G, Callieri C, Bertoni R, Caravati E (July 2010). "Ultraviolet radiation induces filamentation in bacterial assemblages from North Andean Patagonian lakes". Photochemistry and Photobiology. 86 (4): 871–881. doi:10.1111/j.1751-1097.2010.00758.x. PMID   20528974. S2CID   45542973.
  21. Walker JR, Pardee AB (January 1968). "Evidence for a relationship between deoxyribonucleic acid metabolism and septum formation in Escherichia coli". Journal of Bacteriology. 95 (1): 123–131. doi:10.1128/JB.95.1.123-131.1968. PMC   251980 . PMID   4867214.
  22. Ohkawa T (December 1975). "Studies of intracellular thymidine nucleotides. Thymineless death and the recovery after re-addition of thymine in Escherichia coli K 12". European Journal of Biochemistry. 60 (1): 57–66. doi: 10.1111/j.1432-1033.1975.tb20975.x . PMID   1107038.
  23. Jensen RH, Woolfolk CA (August 1985). "Formation of Filaments by Pseudomonas putida". Applied and Environmental Microbiology. 50 (2): 364–372. Bibcode:1985ApEnM..50..364J. doi:10.1128/aem.50.2.364-372.1985. PMC   238629 . PMID   16346856.
  24. Tran TD, Ali MA, Lee D, Félix MA, Luallen RJ (February 2022). "Bacterial filamentation as a mechanism for cell-to-cell spread within an animal host". Nature Communications. 13 (1): 693. Bibcode:2022NatCo..13..693T. doi:10.1038/s41467-022-28297-6. PMC   8816909 . PMID   35121734.
  25. Bhattacharyya S, Bershtein S, Adkar BV, Woodard J, Shakhnovich EI (June 2021). "Metabolic response to point mutations reveals principles of modulation of in vivo enzyme activity and phenotype". Molecular Systems Biology. 17 (6): e10200. arXiv: 2012.09658 . doi:10.15252/msb.202110200. PMC   8236904 . PMID   34180142.
  26. Lau SY, Zgurskaya HI (November 2005). "Cell division defects in Escherichia coli deficient in the multidrug efflux transporter AcrEF-TolC". Journal of Bacteriology. 187 (22): 7815–7825. doi:10.1128/JB.187.22.7815-7825.2005. PMC   1280316 . PMID   16267305.
  27. Gode-Potratz CJ, Kustusch RJ, Breheny PJ, Weiss DS, McCarter LL (January 2011). "Surface sensing in Vibrio parahaemolyticus triggers a programme of gene expression that promotes colonization and virulence". Molecular Microbiology. 79 (1): 240–263. doi:10.1111/j.1365-2958.2010.07445.x. PMC   3075615 . PMID   21166906.
  28. Corno G, Jürgens K (January 2006). "Direct and indirect effects of protist predation on population size structure of a bacterial strain with high phenotypic plasticity". Applied and Environmental Microbiology. 72 (1): 78–86. Bibcode:2006ApEnM..72...78C. doi:10.1128/AEM.72.1.78-86.2006. PMC   1352273 . PMID   16391028.
  29. Ryan RP, Fouhy Y, Garcia BF, Watt SA, Niehaus K, Yang L, et al. (April 2008). "Interspecies signalling via the Stenotrophomonas maltophilia diffusible signal factor influences biofilm formation and polymyxin tolerance in Pseudomonas aeruginosa". Molecular Microbiology. 68 (1): 75–86. doi: 10.1111/j.1365-2958.2008.06132.x . PMID   18312265. S2CID   26725907.
  30. Finer KR, Larkin KM, Martin BJ, Finer JJ (February 2001). "Proximity of Agrobacterium to living plant tissues induces conversion to a filamentous bacterial form". Plant Cell Reports. 20 (3): 250–255. doi:10.1007/s002990100315. S2CID   24531530.
  31. Mohamed-Salem R, Rodríguez Fernández C, Nieto-Pelegrín E, Conde-Valentín B, Rumbero A, Martinez-Quiles N (2019). "Aqueous extract of Hibiscus sabdariffa inhibits pedestal induction by enteropathogenic E. coli and promotes bacterial filamentation in vitro". PLOS ONE. 14 (3): e0213580. Bibcode:2019PLoSO..1413580M. doi: 10.1371/journal.pone.0213580 . PMC   6407759 . PMID   30849110.