The general research interest in my lab is focused on the broad fields of genomics, functional genomics, taxonomy and ecology of a unique predatory group of bacteria, the Bdellovibrio and like-organisms (Bd) as well as the use of these predators to eliminate pathogenic gram negative bacteria during infection.
Bd invades and reproduces in other gram negative bacteria and it is an interesting model organism to study both from the point of view of understanding cell invasion and for its potential as an antimicrobial agent or therapy.
Bds are gram-negative prokaryotes isolated from very diverse environments that attack and grow in the periplasm of some other gram-negative bacteria resulting in their lysis. They have a biphasic life cycle with an attack phase where the free and small vibrioid shaped flagellated cells swim in a random direction until finding a prey cell. During the growth phase in the periplasm of the prey, the Bd utilizes the invaded cell material as a source of organic substrates. The Bds elongates, replicates by segmentative fragmentation and finally lyses the prey cell releasing the progeny.
The Bdellovibrio and like-organisms prey on a wide range of bacteria including pathogenic species like Pseudomonas, Salmonella, E coli and Vibrio, independent of the pathogen's antibiotic resistance profile. Antibiotic resistance is viewed by many as having reached crisis proportions in gram-negative bacterial infections.
The options for therapy are becoming extremely limited, heightening the interest in developing alternative antimicrobial agents. One that has shown potential is the uses of lytic enzymes from phages to control infections with gram-positive bacteria. Following this thinking, one of our long term goals is to identify lytic enzymes from Bdellovibrio and like organisms that can be used to eliminate bacterial infections with gram-negative bacteria. One of the objectives of our research is to identify the lytic enzymes that are involved in the predatory invasion and lysis process by Bdellovibrio HD100 which could constitute the new generation of antimicrobial agents to use in gram-negative bacterial infections.
During the last 4 years, we have completed an exhaustive study of phylogenetic diversity in saltwater Bacteriovorax using 16S rRNA [Pineiro et al., 2007], rpoB (in press), and MLST (manuscript in preparation) gene analyses, and studied the genotype distribution patterns in two major estuaries (manuscript in preparation).
A successful primer was developed for the quantification of saltwater Bd using qPCR (manuscript in review), and we have collaborated on the genome sequencing of the first saltwater Bd [http://www.sanger.ac.uk/Projects/B_marinus/].
We have identified, cloned, constructed site-directed point mutations of, and expressed Nudix hydrolase genes from HD100 (manuscript in preparation) and HDSJ (manuscript in preparation).
We are the first group to accomplish an in-frame knockout mutation (single gene inactivation) in Bd, and have determined a suitable vector for use in complementation assays [Steyert and Pineiro, 2007]. We have prepared promoter libraries for HD100 and HDSJ, with sequence analysis in progress.
Steyert S., Messing S., Gabelli, S., Amzel M. and Pineiro S.A. (2008). “Identification of Bdellovibrio bacteriovorus HD100 Bd0714 as a Nudix dGTPase”. Journal of Bacteriology. Dec;190(24):8215-9.
Mally Dori-Bachash, Bareket Dassa, Ofer Peleg, Silvia A. Pineiro, Edouard Jurkevitch and Shmuel Pietrokovski. (2008) “A new Type of Bacterial Intein-like Domains Specific to Predatory Bacteria Characterized in Bdellovibrio bacteriovorus”. Functional & Integrative Genomics. In press
Messing S., Gabelli, S., Liu Q., Celesnik H., Belasco, J., Pineiro S.A. and S., Amzel M. (2008) “Structure and biological function of the RNA pyrophosphohydrolase BdRppH from Bdellovibrio bacteriovorus”. Structure, Cell Press. In press
Zheng, G., Wang, C., Williams, H., Pineiro, S. (2008) Development and Evaluation of a Quantitative Real-Time PCR Assay for the Detection of Saltwater Bacteriovorax. Environmental Microbiology (EM). 10(10), 2515-2526.
Pineiro S., Williams, H., and Stine OC. (2008) Phylogenetic Relationships Amongst the Saltwater Members of the Genus Bacteriovorax Using rpoB Sequences and Reclassification of Bacteriovorax stolpii as Bacteriolyticum stolpii gen. nov., comb. nov. International Journal of Systematic and Evolutionary Microbiology (IJSEM). May; 58:1203-1209.
Pineiro S., O. C. Stine, R. Smith, S. Steyert and H.N. Williams. (2007) Global Survey of Diversity Among Environmental Saltwater Bacteriovoracaceae. Environmental Microbiology (EM) 2007 Oct;9(10):2441-50.
Steyert S. and Pineiro S. (2007) Development of a Novel Genetic System to Create Markerless Deletions in Bdellovibrio bacteriovorus. Applied and Environmental Microbiology (AEM) 73:4717-4724. This article was selected as one of the six best ASM journal articles for the month, to be published in the Journal Highlights section of Microbe.
Williams, H. and Pineiro S. (2006) Ecology of the Predatory Bdellovibrio and Like Organisms. Book chapter. E. Jurkevitch: Predatory Prokaryotes. Springer-Verlag. In press.
Crespo O, Catalano M, Pineiro S, Matteo M, Leanza A, Centron D. (2005) Tn7 distribution in Helicobacter pylori: a selective paradox. Int J Antimicrob Agents. 25(4):341-4.
Pineiro, S.A., Sahaniuk, G.E., Romberg E., Williams, H.N. (2004) Predation Pattern and Phylogenetic Analysis of Bdellovibrionacea from the Great Salt Lake, Utah. Current Microbiology. 48(2):113-117.
Smith RS., SA. Pineiro, R Singh, E. Romberg, ME. Labib and HN. Williams (2004) Discrepancies in Bacterial Recovery from Dental Unit Water Samples on R2A Medium and Commercial Sampling Devicea. Current Microbiology. 48(4):243-6
Baer M., Ravel J., Pineiro S., and Williams H. (2004). A proposal for two new species, Bacteriovorax marinus sp. nov. and Bacteriovorax litoralis sp. nov. IJSEM. 54: 1011-1016.
Barbolla R., M. Catalano, B.E. Orman, A. Famiglietti, C. Vay, J. Smayevsky, D. Centron, S.A. Pineiro. (2004) Study of Class I Integrons from Epidemiologically Unrelated Stenotrophomonas maltophilia Isolates and the Increase of Trimethoprim-Sulfamethoxazole Resistance. Antimicrob Agents Chemother. 48(2):666-9.
Orman BE, Pineiro SA, Arduino S, Galas M, Melano R, Caffer MI, Sordelli DO, Centron D. (2002) Evolution of multiresistance in nontyphoid salmonella serovars from 1984 to 1998 in Argentina. Antimicrob Agents Chemother. Dec;46(12):3963-70.
Arduino S., Roy P. H., Jacoby G. A., Orman B., Pineiro S. and Centron D. (2002) obla(CTX-M-2) Is Located in an Unusual Class 1 Integron (In35) Which Includes Orf513. Antimicrob Agents Chemother. Jul; 46 (7): 2303-2306
Pineiro S., Sordelli D. and Centron D. (2000). Development of a plasmid for promoter selection. Current Mibrobioloby. An International Journal. Vol. 40 p. 302-305.
Pineiro S., Olekhnovich, I. and Gussin, G. (1997) DNA bending by TrpI protein of Pseudomonas aeruginosa. Journal of Bacteriology. Vol. 179 17 p. 5407-5413.
Centron Garcia, D.; Catalano, M.; Pineiro, S.; Woloj M.; Kaufman, S. and Sordelli, D. (1996) The emergence of resistance to amikacin in Serratia marcescens isolates from patients with Nosocomial infections. International Journal of Antimicrobial Agents. (Elsevier). 7 203-210.
Centron Garcia, D.; Woloj M.; Sordelli, D.; Kaufman, S. and Pineiro, S. (1995) Sequences related to Tn1331 associated with multiple antimicrobial resistance in different Salmonella serovars. International Journal of Antimicrobial Agents. (Elsevier). 5 199-202.
Centron Garcia, D.; Woloj M.; Pineiro, S.; Sordelli, D. and Kaufman, S. (1995) An 8-years study on resistance to amikacin in Gram-Negative bacilli isolates from patients with Nosocomial infection at one hospital in Argentina. Journal of Medical Microbiology. Vol. 42 283-290.
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