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Featured researches published by M.Y. Popoff.


International Journal of Systematic and Evolutionary Microbiology | 1987

Designation of Salmonella enterica sp. nov., nom. rev., as the Type and Only Species of the Genus Salmonella: Request for an Opinion

M.Y. Popoff

Since the publication of the Approved Lists of Bacterial Names, the type species of the genus Salmonella has been S. choleraesuis. At the time of publication of the Approved Lists, five Salmonella species had standing in the nomenclature, and the description of S. choleraesuis was the same as that of the serotype of that name. Several studies have shown that the genus Salmonella consists of only one species, and the strict application of the Bacteriological Code would recognize S. choleraesuis (the type species) as the single Salmonella species. This can lead to confusion and hazards since the specific epithet is also the name of a serovar (serovar Choleraesuis). This confusion is increased by the common practice of using serovar names as if they represented species names (e.g., S. typhi, S. choleraesuis, and S. typhimurium). Some serovars (e.g., Salmonella choleraesuis subsp. choleraesuis serovar Typhi) are highly pathogenic and cause a disease different from that caused by other serovars (e.g. S. choleraesuis subsp. choleraesuis serovar Choleraesuis). To avoid further confusion, it is proposed to use for the single Salmonella species a name which has not been used earlier for a serotype. It is thus requested that the type species of the genus Salmonella be Salmonella enterica sp. nov., nom. rev. with strain CIP 60.62 (a H2S-producing clone of strain LT2) as the type strain. Since the name S. choleraesuis is not proposed for rejection, bacteriologists who do not accept the single species concept of the genus Salmonella will be free to use the name S. choleraesuis as a synonym of Salmonella enterica subsp. enterica serotype Choleraesuis.


International Journal of Systematic and Evolutionary Microbiology | 1988

Ochrobactrum anthropi gen. nov., sp. nov. from Human Clinical Specimens and Previously Known as Group Vd

B. Holmes; M.Y. Popoff; M. Kiredjian; Karel Kersters

In this study we examined the taxonomic relationships of strains variously labeled Achromobacter species biotypes 1 and 2, Achromobacter group A, and Centers for Disease Control (CDC) groups Vd-1 and Vd-2. Previous studies of ribosomal ribonucleic acid cistron similarities placed these organisms on the Brucella ribosomal ribonucleic acid branch of ribosomal ribonucleic acid superfamily IV; their closest neighbors were Brucella, Phyllobacterium, and the Agrobacterium-Rhizobium complex. We performed a numerical taxonomic analysis of 284 phenotypic features (69 conventional tests, 147 API assimilation tests, 68 API ZYM tests) carried out on 95 strains. These organisms comprised 56 strains thought to correspond to CDC group Vd (including 3 strains originally labeled “Pseudomonas arsenoxydans”) and 39 strains (included for reference purposes) representing the genera Achromobacter, Agrobacterium, Alcaligenes, Brucella, Mycoplana, Phyllobacterium, and Rhizobium. A phenotypic analysis showed that group Vd bacteria are most similar to Phyllobacterium. However, strains of Group Vd were shown to be distinct by deoxyribonucleic acid (DNA)-DNA hybridization and by several phenotypic tests from Phyllobacterium and other related taxa. The CDC group Vd strains formed essentially a single taxon in the numerical taxonomic analysis of phenotypic characters and as determined by DNA-DNA hybridization. This taxon could be subdivided into three biotypes (biotypes A, C, and D), but none of these corresponded to the two biotypes originally described among the group Vd strains. For CDC group Vd we propose a new genus and new species, Ochrobactrum anthropi: The type strain is strain CIP 82.115 (= CIP 14970 = NCTC 12168 = LMG 3331). O. anthropi strains are rod shaped, aerobic, gram negative, nonpigmented, and motile by means of peritrichous flagella, produce acid from several carbohydrates, and reduce both nitrate and nitrite. The guanine-plus-cytosine contents of the DNAs of 29 strains ranged from 56 to 59 mol%. Almost all 56 group Vd strains were originally isolated from various human clinical specimens, commonly from blood cultures.


Annales De L'institut Pasteur. Microbiologie | 1986

Virulence-associated plasmids of Salmonella serotype typhimurium in experimental murine infection

Pierre Pardon; M.Y. Popoff; Colette Coynault; J. Marly; I. Miras

The growth pattern of Salmonella enterica subsp. enterica serotype Typhimurium (Typhimurium) was studied in mice to examine the role of the 60-Mdal virulence-associated plasmid in the pathogenesis of mouse typhoid. After repeated subcultures at 45 degrees C, isogenic variants harbouring the virulence-associated plasmid (strains C52, TM122 and TM332) or having lost this large plasmid (strains C53, TM123 and TM333) were obtained from three parental strains (strains C5, TM12 and TM33, respectively). Plasmid pIP1350, present in strain C52, was tagged by Tn10 and transferred by successive conjugations to strains C53, TM123 and TM333. The behaviour of these three Typhimurium lines was studied in C57BL/6, DBA2, B6D2 (C57BL/6 X DBA2 F1 hybrid) and OF1 mice after oral infection, subcutaneous injection into the hind footpad or intravenous inoculation. The kinetics of organ colonization were followed at intervals after injection by enumeration of viable bacteria in caecum, mesenteric or popliteal lymph node, spleen, liver, kidney and lung depending on the route of infection. Strains harbouring virulence plasmid and their cured derivatives did not differ significantly in their ability to colonize caecal content and to translocate to draining lymph nodes. Elimination of the virulence plasmid was correlated with a significant reduction in the ability of cured variants to colonize spleen and liver. Reintroduction of the virulence plasmid into plasmidless variants restored the virulence to the level originally observed. These data demonstrate that a 60-Mdal plasmid in Typhimurium strains is necessary to ensure colonization of spleen and liver of experimentally infected mice.


Journal of Bacteriology | 2004

The PmlI-PmlR Quorum-Sensing System in Burkholderia pseudomallei Plays a Key Role in Virulence and Modulates Production of the MprA Protease

E. Valade; F. M. Thibault; Y. P. Gauthier; M. Palencia; M.Y. Popoff; D. R. Vidal

Burkholderia pseudomallei is the causative agent of melioidosis, an often fatal infection of humans and animals. The virulence of this pathogen is thought to depend on a number of secreted proteins, including the MprA metalloprotease. We observed that MprA is produced upon entry into the stationary phase, when the cell density is high, and this prompted us to study cell density-dependent regulation in B. pseudomallei. A search of the B. pseudomallei genome led to identification of a quorum-sensing system involving the LuxI-LuxR homologs PmlI-PmlR. PmlI directed the synthesis of an N-acylhomoserine lactone identified as N-decanoylhomoserine lactone. A B. pseudomallei pmlI mutant was significantly less virulent than the parental strain in a murine model of infection by the intraperitoneal, subcutaneous, and intranasal routes. Inactivation of pmlI resulted in overproduction of MprA at the onset of the stationary phase. A wild-type phenotype was restored following complementation with pmlI or addition of cell-free culture supernatant. In contrast, there was no significant difference between the virulence of a B. pseudomallei mprA mutant and the virulence of the wild-type strain. These results suggest that the PmlI-PmlR quorum-sensing system of B. pseudomallei is essential for full virulence in a mouse model and downregulates the production of MprA at a high cell density.


Molecular Microbiology | 1989

Cloning and expression of plasmid DNA sequences involved in Salmonella serotype Typhimurium virulence

Françoise Norel; Colette Coynault; Isabelle Miras; Daniel Hermant; M.Y. Popoff

A 22 kb region of the 90kb virulence‐associated plasmid, plP1350, of Typhimurium strain C52 was cloned into the mobilizable vector pSUP202, yielding plasmid plP1352. This recombinant plasmid restored full virulence to plasmidless strain C53 in a mouse model. Transposon Tn5 insertion mutagenesis demonstrated the existence of two DNA sequences in plP1352 designated VirA and VirB, both of which are essential for the expression of virulence. A recombinant plasmid containing only the VirA and VirB regions markedly increased the virulence of the plasmidless strain C53, but did not confer full virulence. These results suggested that a third virulence‐associated region might be present on plP1352. Eleven proteins encoded by the 22 kb insert sequence of pl P1352 were identified in Escherichia coli SE5000 maxicells. The VirA region encoded at least two proteins with apparent molecular weights of 71000 and 28000 and the VirB region encoded two proteins of 43000 and 38000.


Annales De L'institut Pasteur. Microbiologie | 1985

Expression of antigenic factor O:54 is associated with the presence of a plasmid in Salmonella.

M.Y. Popoff; L. Le Minor

Salmonella serovar Tonev (antigenic formula, 21,54:b:e,n,x) is classified in the Salmonella group O:54, and contains a 7.5-kilobase plasmid, designated pIP1340. Tonev NV, a variant lacking pIP1340, failed to express O:54 (antigenic formula identical with that of serovar Minnesota, 21:b:e,n,x). Phenotypic tagging of plasmid pIP1340 by transposon Tn5 produced plasmid pIP1341. Factor O:54 expression in Tonev NV was restored after transformation by pIP1341 NDA or after co-transformation by a mixture of pBR322 and pIP1340 DNA. Similarly, the twelve other serovars presently classified in Salmonella group O:54 harboured a small plasmid which was not detectable in isogenic O:54-negative variants isolated from the parent strain. Transfer of plasmid pIP1341 into these O:54-negative variants and also into reference strains of serovars of Salmonella group O:4 (Banana and Typhimurium), group O:7 (Thompson and Mbandaka), group O:8 (Ferruch, Hadar and Kentucky), group O:3,10 (Orion) and group O:21 (Minnesota) supported the conclusion that plasmid pIP1340 encodes or regulates some functions required for factor O:54 expression by various serovars of Salmonella.


Annales De L'institut Pasteur. Microbiologie | 1986

Individualisation d'une septième sods-espèce de salmonella: s. choleraesuis subsp. indica subsp. nov.

L. Le Minor; M.Y. Popoff; B. Laurent; D. Hermant

Summary A new Salmonella subspecies designated as S. choleraesuis subsp. indica (shortly, subspecies VI) was delineated on the basis of biochemical characters and genomic relatedness. Eight serovars were assigned to this subspecies: one of these was previously classified in subspecies I (serovar Ferlac) and seven in subspecies II. This subspecies can be identified by five biochemical characters: gelatinase + , malonate − , L(+)tartrate − , salicin − and sorbitol si−. The type strain is CIP 102501 (serovar 1,6,14,25:a:e,n,x formerly called Ferlac).


Research in Microbiology | 1998

Supplement 1997 (no. 41) to the Kauffmann-White scheme

M.Y. Popoff; Jochen Bockemühl; Frances W. Brenner

This supplement reports the characterization of 15 new Salmonella serovars recognized in 1997 by the WHO Collaborating Centre for Reference and Research on Salmonella: 8 were assigned to S. enterica subsp. enterica, 4 to subspecies salamae, 2 to subspecies diarizonae, and 1 to subsp. houtenae. In addition, the antigenic factors H:z85 and H:z87 are described and one modification to the Kauffmann-White scheme is reported.


Research in Microbiology | 1997

Molecular characterization of the Salmonella typhi StpA protein that is related to both Yersinia YopE cytotoxin and YopH tyrosine phosphatase.

Nathalie Arricau; Daniel Hermant; Hervé Waxin; M.Y. Popoff

Analysis of the nucleotide sequence of a 4-kb DNA fragment located between the sip and iag loci on Salmonella typhi chromosome revealed three open reading frames, termed sipF, ctpA and stpA. The 82-amino-acid (aa) sipF product showed extensive similarity to the lacP protein from S. typhimurium. The StpA protein (535 aa) exhibited significant similarity to both Yersinia enterocolitica YopE cytotoxin and YopH tyrosine phosphatase. The CtpA polypeptide (130 aa) might be the molecular chaperone of the StpA protein.


Research in Microbiology | 1992

Supplement 1991 (no. 35) to the Kauffmann-White scheme

M.Y. Popoff; J. Bockemühl; A. McWhorter-Murlin

Abstract This supplement reports the characterization of 28 new Salmonella serovars recognized in 1991 by the WHO Collaborating Centre for Reference and Research on Salmonella : 12 were assigned to S. enterica subsp. enterica , 10 to subspecies salamae , 4 to subspecies diazonae and 2 to S. bongori .

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A. McWhorter-Murlin

Centers for Disease Control and Prevention

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F.W. Hickman-Brenner

Centers for Disease Control and Prevention

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