Cited by 262Microbial Natural Products and BiosynthesisPlant Pathogens and Fungal DiseasesMycotoxins in Agriculture and Food

The DOI matches its Crossref record; 34 of the 34 references it cites were found in a registry or an index; 1 of the 7 sources its claims cite were checked for support.

Fleming’s penicillin producing strain is not Penicillium chrysogenum but P. rubens

Open access

Abstract

Penicillium chrysogenum is a commonly occurring mould in indoor environments and foods, and has gained much attention for its use in the production of the antibiotic penicillin. Phylogenetic analysis of the most important penicillin producing P. chrysogenum isolates revealed the presence of two highly supported clades, and we show here that these two clades represent two species, P. chrysogenum and P. rubens. These species are phenotypically similar, but extrolite analysis shows that P. chrysogenum produces secalonic acid D and F and/or a metabolite related to lumpidin, while P. rubens does not produce these metabolites. Fleming's original penicillin producing strain and the full genome sequenced strain of P. chrysogenum are re-identified as P. rubens. Furthermore, the well-known claim that Alexander Fleming misidentified the original penicillin producing strain as P. rubrum is discussed.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

Phylogenetic and extrolite analyses show that *Penicillium chrysogenum* sensu lato comprises two species, *P. chrysogenum* and *P. rubens*. Fleming’s original penicillin-producing strain, the Wisconsin wild-type strain, and the full genome-sequenced strain are all re-identified as *P. rubens*.

Key findings

  • Combined β-tubulin, calmodulin, and RPB2 data resolve two highly supported clades: one around the ex-type of *P. chrysogenum* (CBS 306.48), the other around the ex-type of *P. rubens* (NRRL 792).
  • Fleming’s original penicillin strain (CBS 205.57), the wild-type Wisconsin strain (CBS 307.48 = NRRL 1951), the full genome-sequenced strain Wisconsin 54-1255, and the submerged-production strain CBS 197.46 = NRRL 832 all fall in the *P. rubens* clade.
  • *P. chrysogenum* produces secalonic acid D and F and/or a lumpidin-related metabolite, whereas *P. rubens* does not produce these metabolites.
  • Phenotypic macro- and microscopic characters did not clearly separate the two species; three strains showed deviating growth: CBS 355.48 had smaller colonies, while NRRL 792 and CBS 307.48 had reduced sporulation on most agar media.

Methods

  • Morphology: strains from Table 1 were inoculated on CYA, YES, CREA, and MEA, incubated 7 d at 25 °C, and examined macro- and microscopically.
  • Molecular analysis: partial β-tubulin, calmodulin, and RPB2 were sequenced; maximum likelihood used RAxML v. 7.2.8 with GTR and separate partitions, and maximum parsimony used MEGA5 with 500 bootstrap replicates; *P. griseofulvum* CBS 185.27 was the outgroup. The calmodulin partition was 506 bp with 90 distinct alignment patterns, RPB2 was 981 characters with 91 distinct patterns, and β-tubulin was 434 bp with 62 distinct patterns; parsimony analysis found 118 parsimony-informative sites (3150 MP trees, length = 400, CI 0.69, RI 0.83).
  • Extrolite analysis: strains were grown 7–14 d at 25 °C on YES, CYA, and MEA, then extracted and analyzed by HPLC-DAD against characterized compounds.

Limitations

  • Stated in the paper: the status of Scott et al. lineage 3 remains under investigation; a more detailed molecular or extrolite analysis is needed to place additional synonyms within *P. chrysogenum*, *P. rubens*, or other unrecognized species; and the suggestion that *P. rubens* has a competitive advantage in indoor niches requires investigation of distribution patterns in other geographic regions.
  • Evident from the text: phenotypic examination did not reveal clear differences between the two species, so separation depends on molecular and extrolite data; the study focuses on historically important penicillin-producing strains rather than a comprehensive population sample.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.5598/imafungus.2011.02.01.12

Cites

34 of 34 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Figures

Fig. 1 Best scoring ML tree of combined partial β-tubulin, calmodulin and RPB2 datasets. The bootstrap values of the maximum likelihood analysis (ML, first number) and maximum parsimony analysis (MP, second number) are shown at the nodes. The bootstrap values above 70 % are shown and branches supported less than 70 % in either the MP or ML analysis are indicated with a hyphen.
Fig. 1 Best scoring ML tree of combined partial β-tubulin, calmodulin and RPB2 datasets. The bootstrap values of the maximum likelihood analysis (ML, first number) and maximum parsimony analysis (MP, second number) are shown at the nodes. The bootstrap values above 70 % are shown and branches supported less than 70 % in either the MP or ML analysis are indicated with a hyphen.CC BY-NC-ND · PubMed Central
Fig. 2 Penicillium rubens CBS 205.57 (Fleming’s original penicillin-producer). A–C. Colonies 7 d old 25 °C. A. CYA. B. MEA. C. YES. D–H. Condiophores. I. Conidia. Bars = 10 μm.
Fig. 2 Penicillium rubens CBS 205.57 (Fleming’s original penicillin-producer). A–C. Colonies 7 d old 25 °C. A. CYA. B. MEA. C. YES. D–H. Condiophores. I. Conidia. Bars = 10 μm.CC BY-NC-ND · PubMed Central
Fig. 3 Penicillium rubens NRRL 792. A–C. Colonies 7 d old 25 °C. A. CYA. B. MEA. C. YES. D–H. Condiophores. I. Conidia. Bars = 10 μm.
Fig. 3 Penicillium rubens NRRL 792. A–C. Colonies 7 d old 25 °C. A. CYA. B. MEA. C. YES. D–H. Condiophores. I. Conidia. Bars = 10 μm.CC BY-NC-ND · PubMed Central

Verification

Claims the paper makes

8 Own result · 4 Own interpretation · 2 No full text of the sources · 1 Partly supported · 1 Sources not found · 1 Not checked yet · 1 No basis given · accuracy not yet measured

Show all 11 claims

  • It may state two separate claims as one. 7
7 of 7
  • The paper relies on this without support.

    Fleming’s original penicillin producing strain is CBS 205.57.

    “Fleming’s original penicillin producing strain (CBS 205.57)”
  • The paper relies on this without support.

    The wild-type Wisconsin strain isolated from a mouldy cantaloupe is CBS 307.48 = NRRL 1951.

    “the wild-type Wisconsin strain isolated from a mouldy cantaloupe (CBS 307.48 = NRRL 1951)”
  • The paper relies on this without support.

    The strain first found to produce satisfactory yields of penicillin when grown submerged is CBS 197.46 = NRRL 832.

    “the strain first found to produce satisfactory yields of penicillin when grown submerged (CBS 197.46 = NRRL 832)”
3 of 3

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

1 of 1

Citations

Cites

Show all 32 references

Research works printed but not linked: 6

  1. Biourge P (1923) Les moisissures du groupe Penicillium Link. Cellule 33: 7–331.
  2. Gravesen S (1999) Microfungal contamination of damp buildings. In: Johanning E (ed.), Bioaerosols, Fungi and Mycotoxins: 505–515. [Proceedings of the Third International Conference on Fungi, Mycotoxins and Bioaerosols. Saratoga Springs, New York. September 23–25, 1998.] Albany, NY: Eastern New York Occupational and Environmental Health Center.
  3. Hare R (1970) The Birth of Penicillin and the Discovery of Microbes. London: George Allen & Unwin.
  4. Raper KB, Thorn C (1949) Manual of the Penicillia. Baltimore: Williams & Wilkins.
  5. Stoll O (1904) Beiträge zur Morphologischen und Biologischen Charakteristik von Penicillium-Arten. Inaugural Dissertation, Würzburg.
  6. Thorn C (1930) The Penicillia. Baltimore: Williams and Wilkins.

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Metadata

Authors
Houbraken, J., Frisvad, J. C., & Samson, R. A.
Affiliations
  • Westerdijk Fungal Biodiversity Institute (NL)
  • Technical University of Denmark (DK)
Corresponding author
Houbraken, Jos
Venue
IMA Fungus
Published
2011-06
Volume
2
Issue
1
Pages
87-95
ISSN
  • 2210-6340 (ISSN-L)
  • 2210-6359
OpenAlex
W2149410962
Cited by
262
References
32
Citations by year
2026: 9 · 2025: 14 · 2024: 13 · 2023: 45 · 2022: 26 · 2021: 24 · 2020: 21 · 2019: 10 · 2018: 13 · 2017: 18 · 2016: 15 · 2015: 17 · 2014: 15 · 2013: 11 · 2012: 7
FWCI
8.67
Type
journal article
Language
en
Open access
Locations
  • IMA Fungus (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • KNAW Research Portal (The Royal Netherlands Academy of Arts and Sciences) (publishedVersion, other-oa)
  • Data Archiving and Networked Services (DANS) (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • Technical University of Denmark, DTU Orbit (Technical University of Denmark, DTU) (submittedVersion, cc-by-nc-nd)
  • KNAW research portal (Royal Academy of Art and Sciences (KNAW)) (submittedVersion, other-oa)
Topics
  • Life Sciences › Immunology and Microbiology › Applied Microbiology and Biotechnology › Microbial Natural Products and Biosynthesis
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Plant Pathogens and Fungal Diseases
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Mycotoxins in Agriculture and Food
Keywords
Penicillium chrysogenum, Penicillium rubens, penicillin production, phylogenetic analysis, secalonic acid D, Alexander Fleming, Penicillium rubrum, fungal taxonomy

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