Luis A. Actis
Retired: January 29, 2024
Note: I am no longer taking graduate students as I have retired.
Education
B.S. in Biochemistry
Ph.D. in Biochemistry, Universidad Nacional de Cordoba, 1982
Biographical Information
After earning a BS degree in Biochemistry, I earned in 1982 a PhD degree in Biochemistry from the Universidad Nacional de Cordoba, Argentina under de supervision of Dr. Luis Patrito, with whom we studied the synthesis of human placental proteins.
During my postdoctoral training and Research Faculty appointment in the Department of Microbiology at the Oregon Health Science University between 1983 and 1993, I worked on the characterization of iron acquisition systems expressed by the fish pathogen under the guidance of Dr. Jorge H. Crosa. During this training, I started my work with the human pathogen Acinetobacter baumannii which I continued after I joined the Department of Microbiology at Miami University in 1994, where I was able to develop my academic and scholarly career.
Research Interests
- Bacterial Pathogenesis
- Bacterial Iron Metabolism
- Acinetobacter baumannii Virulence
- Light Sensing and Regulation of Gene Expression
The research in my laboratory centered on the genetic, molecular, and functional analyses of some of the factors responsible for the ability of the bacterium Acinetobacter baumannii to persist in medical environments and cause serious infections in humans. Although A. baumannii has been known for a long time as the etiological agent of a wide range of opportunistic nosocomial infections, it has recently emerged as a more serious threat to human health because of its ability to cause devastating infections among wounded military personnel that are very difficult to treat because of antibiotic resistance. Another serious problem with this bacterial pathogen is the lack of understanding of its virulence factors, which could be used as new and alternative targets to prevent and treat the infections it causes in humans.
Based on these considerations, one of our research projects focused on the mechanisms A. baumannii uses to acquire iron under limiting conditions such as those encountered in the human host. Our research proved that A. baumannii expresses different iron acquisition systems, including hemin utilization functions and siderophore-mediated systems, one of which is highly similar to a system found in the fish pathogen Vibrio anguillarum. This finding suggests that siderophore-mediated iron acquisition systems are part of mobile genetic elements that can be transferred among bacterial cells belonging to different genera and species, which cause severe infections in unrelated hosts. We have also detected the presence of genes encoding proteins belonging to the efflux pump protein family, which could play a role in siderophore secretion, and identified protein secretory functions that have never been associated with iron acquisition in bacteria. These are significant and exciting observations that have the potential to increase our understanding of iron utilization and metabolism in bacteria.
Although a large body of knowledge exists regarding iron acquisition in bacteria, almost all of it was obtained with planktonic cells that most likely do not reflect the cell arrangements found in nature. In contrast, little is known about the iron acquisition processes expressed by cells arranged in biofilm structures, which are more representative of bacterial arrangements found in the environment. There is evidence that natural iron chelators such as lactoferrin and transferrin play a role in biofilm formation and that the amount of siderophore secreted by cells in biofilms is different from that produced by planktonic cells. Consequently, we are also interested in testing the effects of biofilm growth on the expression of genes encoding iron acquisition proteins. We have reported that a chaperone-usher secretion system is needed for the assembly of pili, which are required for cell attachment and biofilm formation on abiotic surfaces. Additional work showed that a couple of regulatory functions, encoded by genes similar to other bacterial genes annotated as hypothetical genes that are part of two-component regulatory systems, are also involved in biofilm formation as well as cell morphology. Incubation of A. baumannii cells with Candida albicans filaments provided evidence that this bacterial pathogen also attaches to biotic surfaces, as it was shown for Pseudomonas aeruginosa using this experimental model. Interestingly, the bacterial cells as well as the culture supernatants kill the fungal filaments by apoptosis. This observation indicates that A. baumannii produces factors that affect the viability of eukaryotic cells and supports the utilization of this experimental model for the identification and analysis of virulence factors produced by this poorly characterized bacterial pathogen. Recently, we have expanded this objective by investigating the interactions of this pathogen with human lung cells, a model that has the potential to provide information on the interaction of A. baumannii with vertebrate cells and organisms.
The overall goal of this multifaceted approach was not only to acquire basic knowledge that deepens our understanding of the pathobiology of this bacterium but also to apply this knowledge to develop new strategies to address the difficulties encountered with the treatment of the infections A. baumannii causes in humans.
Publications
- Nishimura, B., J. Escalante, M. R. Tuttobene, T. Subils, V. Mezcord, C. Pimentel, N. Georgeos, F. Pasteran, C. Rodriguez, R. Sieira, L. A. Actis, M. E. Tolmasky, R. A. Bonomo, and M. S. Ramirez. Acinetobacter baumannii response to cefiderocol challenge in human urine. Scientific Reports, 12:8763, 2022.
- Squire, M. S, H. A. Townsend, A. Islam, and L. A. Actis. Light regulates Acinetobacter baumannii chromosomal and pAB3 plasmid genes at 37°C. Journal of Bacteriology, accepted for publication, 204, e0003222, 2022.
- Squire, M. S, H. A. Townsend, and L. A. Actis. The influence of blue light and the Blsa photoreceptor on the oxidative stress resistance mechanisms of Acinetobacter baumannii. Frontiers in Microbiology, 12:856953, 2022.
- Kumar, A., T. Yang, S. Chakravorty, A. Majumdar, B. M. Nairn, D. A. Six, S L. Price, M. B. Lawrenz, L. A. Actis, M. Marques, T. A. Russo, S M. Newton, and P E. Klebba. Fluorescent sensors of siderophores produced by bacterial pathogens. Journal of Biological Chemistry, 298, 101651, 2022.
- Le, C., C. Pimentel, F. Pasteran, M. R. Tuttobene, T. Subils, J. Escalante, B. Nishimura, S. Arriaga, A. Carranza, V. Mezcord, A. J. Vila, A. Corso, L. A. Actis, M. E. Tolmasky, R. A. Bonomo, and M. S. Ramirez. Human serum proteins and susceptibility of Acinetobacter baumannii to Cefiderocol: Role of iron transport. Biomedicines, 10,600, 2022.
- Palethorpe, S., J. Farrow, G. Wells, M. Milton, L. A. Actis, J. Cavanagh and E. Pesci. Acinetobacter baumannii regulates its stress responses via the BfmRS two-component regulatory system. Journal of Bacteriology, 204, e00494-21, 2022.
- Rainey, A., A. Pierce, X. Deng, L. A. Actis, P. Smith, A. J. Kiss and T. J. Wilson. Validation and deployment of a direct saliva real-time RT-PCR Test on pooled samples for COVID-19 surveillance testing. Plos One, 16, e0261956, 2021.
- Grier, J. T., B. A. Arivett, M. S. Ramirez, R. J. Chosed, J. A. Bigner, E. J. Ohneck, M. L. Metz, C. R. Wood, S. Arce, R. F. Relich, L. A. Actis and S. Fiester. Two Acinetobacter baumannii isolates obtained from a fatal necrotizing fasciitis infection display distinct genomic and phenotypic characteristics in comparison to type strains. Frontiers in Cellular and Infection Microbiology, 11:635673, 2021.
- Le, C,. M. R. Tuttobene, T. Subils, J. Martinez, R. Sieira, K. M. Papp-Wallace, N. Keppetipola, R. A. Bonomo, L. A. Actis, M. E. Tolmasky, M. S. Ramirez. Human pleural fluid and human serum albumin modulate the behavior of a hypervirulent and multidrug-resistant (MDR) Acinetobacter baumannii representative strain. Pathogens, 10, 471, 2021.
- Bogue, A. L., W. Panmanee, C. T. McDaniel, J. E. Mortensen, E. Kamau, L. A. Actis, J. A. Johannigman, and D. J. Hassett. AB569, a non-toxic combination of acidified nitrite and EDTA, is effective at killing the notorious Iraq/Afghanistan combat wound pathogens, multi-drug resistant Acinetobacter baumannii and Acinetobacter spp. Plos One, 16, e0247513, 2021.
- Arivett, B., A. Charnot-Katsikas, C. Bethel, S. E. Fiester and L. A. Actis. Draft Genomes of two Acinetobacter baumannii isolates from a fatal case of necrotizing fasciitis. Microbiology Resource Announcements, 9, e00047-20, 2020.
- Wood, C. R., M. S. Squire, N. L. Finley, R. C. Page, and L. A. Actis. Structural and functional analysis of the Acinetobacter baumannii BlsA photoreceptor and regulatory protein. PLoS ONE, 14, e0220918, 2019.
- Ramirez, M. S., W. F. Penwell, G. M. Traglia, D. L. Zimbler, J. A. Gaddy, N. Nikolaidis, M. D. Adams, R. A. Bonomo, L. A. Actis and M. E. Tolmasky. Identification of potential virulence factors in the model strain Acinetobacter baumannii A118. Frontiers in Microbiology, 10, 1599, 2019.
- Luna, B., K. Ershova, J. Yan, A. Ulhaq, T. Nielsen, S. Hsieh, P. Pantapalangkoor, B Vanscoy, P. G. Ambrose, S. Rudin, K. Hujer, R. Bonomo, L. A. Actis, E. Skaar, and B. Spellberg. Adjunctive transferrin to reduce the emergence of antibiotic resistance in Gram-negative bacteria. Journal of Antimicrobial Chemotherapy, dkz225, 2019.
- Ambrose, P., B. VanScoy, B. Luna, J. Yan, A. Ulhaq, T. Nielsen, S. Rudin, K. Hujer, R. Bonomo, L. Actis, E. Skaar, and B. Spellberg. Apotransferrin in combination with ciprofloxacin slows bacterial replication, prevents resistance amplification, and increases antimicrobial regimen effect. Antimicrobial Agents and Chemotherapy, 63:e00112-19, 2019.
- Hassan, F., S. Ni, T. L. Becker, C. M. Kinstedt, J. L. Abdul-Samad, L. A. Actis, and M. A. Kennedy. Evaluation of the antibacterial activity of 75 mushrooms collected in the Oxford, Ohio USA vicinity. International Journal of Medicinal Mushrooms, 21, 131–141, 2019.
- Fiester, S. E., B. A. Arivett, A. C. Beckett, B. R. Wagner, E. J. Ohneck, R. Schmidt and L. A. Actis. Miltefosine reduces the cytolytic activity and virulence of Acinetobacter baumannii. Antimicrobial Agents and Chemotherapy, 63, e01409-18, 2019.
- Wood, C. R., E. J. Ohneck, R. E. Edelmann and L. A. Actis. A light-regulated type I pilus contributes to Acinetobacter baumannii biofilm, motility, and virulence functions. Infection and Immunity, 86, e00442-18, 2018.
- Draughn, G. L., M. E. Milton, E. A. Feldmann, B. G. Bobay, B. M. Roth, A. L. Olson, R. J. Thompson, L. A Actis, C. Davies, and J. Cavanagh. The structure of the biofilm-controlling response regulator BfmR from Acinetobacter baumannii reveals details of its DNA-binding mechanism. Journal of Molecular Biology, 430, 806-821, 2018.
- Ohneck, E. J., B. A. Arivett, S. E. Fiester, C. R. Wood, M. L. Metz, G. M. Simeone, and L. A. Actis. Mucin acts as a nutrient source and a signal for the differential expression of genes coding for cellular processes and virulence factors in Acinetobacter baumannii. PLoS ONE 13, e0190599, 2018.
- Hanauera, D. I. M. J. Grahamb, SEA-PHAGES, L. Betancur, A. Bobrownicki, S. G. Cresawnd, R. A. Garlena, D. Jacobs-Sera, N. Kaufmann, W. H. Pope, D. A. Russell, W. R. Jacobs Jr., V. Sivanathan, D. J. Asaig, and G. F. Hatfulle. An Inclusive Research-Education Community (iREC): Impact of the SEA-PHAGES program on research outcomes and student learning. Proceedings of the National Academy of Sciences USA, 114, 13531-13536, 2017.
- Álvarez-Fraga, L., S. Rumbo-Feal, A. Pérez, M. J. Gómez, C. Gayoso, J. A. Vallejo, E. J. Ohneck, J. Valle, L. A. Actis, G. Bou and M. Poza. Global assessment of small RNAs reveals a non-coding transcript involved in biofilm formation and attachment in Acinetobacter baumannii. Plos One, 12, e0182084, 2017.
- Luna, B., A. Ulhaq, J. Yan, P. Pantapalangkoor, T. Nielsen, B. Davies, L. A. Actis, and B. Spellberg. Selectable markers for use in genetic manipulation of extreme drug resistant (XDR) Acinetobacter baumannii HUMC1. mSphere, 2, e00140-17, 2017.
- Rumbo-Feal, S., A. Pérez, T. A. Ramelot, L. Álvarez-Fraga, J. A. Vallejo, A. Beceiro, E. J. Ohneck, B. A. Arivett, M. Merino, S. E. Fiester, M. A. Kennedy, L. A. Actis, G. Bou and M. Poza. Contribution of the A. baumannii A1S_0114 gene to the interaction with eukaryotic cells and virulence. Frontiers in Cellular and Infection Microbiology, 7, 108, 2017.
- Fleming, I. D., M. A. Krezalek, N. Belogortseva, A. Zaborin, J. Defazio, L. Chandrasekar, L. A. Actis, O. Zaborina, and J. C. Alverdy. Modeling Acinetobacter baumannii wound infections: the critical role of iron. Journal of Trauma and Acute Care Surgery, 82, 557-565, 2017.
- Pérez, A., M. Merino, S. Rumbo-Feal, L. Álvarez-Fraga, J. A. Vallejo, A. Beceiro, E. J. Ohneck, J. Mateos, P. Fernández-Puente, L. A. Actis, M. Poza and G. Bou. The FhaB/FhaC two component secretion system involved in adhesion of Acinetobacter baumannii AbH12O-A2 strain. Virulence, 7, 443-455, 2016.
- Fiester, S. E., B. A. Arivett, R. E. Schmidt, A. C. Beckett, T. Ticak, M. V. Carrier, E. J. Ohneck, M. L. Metz, M. K. Sellin Jeffries and L. A. Actis. Iron-Regulated phospholipase C activity contributes to the cytolytic activity and virulence of Acinetobacter baumannii. PLoS One, 11, e0167068, 2016.
- Arivett, B., D. Ream, S. E. Fiester, Destaalem Kidane, and L. A. Actis. Draft Genomes of Escherichia coli isolates from wounded military personnel. Genome Announcements, 11, e00828-16, 2016.
- Arivett, B., D. Ream, S. E. Fiester, Destaalem Kidane, and L. A. Actis. Draft Genomes of Pseudomonas aeruginosa isolates from wounded military personnel. Genome Announcements, 11, e00829-16, 2016.
- Arivett, B., D. Ream, S. E. Fiester, Destaalem Kidane, and L. A. Actis. Draft genomes of Acinetobacter baumannii isolates from wounded military personnel. Genome Announcements, 25, e00773-16, 2016.
- Álvarez-Fraga, L., A. Pérez, S. Rumbo-Feal, M. Merino, J. A. Vallejo, E. J. Ohneck, R. E. Edelmann, A. Beceiro, J. C. Vázquez-Ucha, J. Valle, L. A. Actis, G. Bou and M. Poza. Analysis of the role of the LH92_11085 gene of a biofilm hyper-producing Acinetobacter baumannii strain on biofilm formation and attachment to eukaryotic cells. Virulence, 7, 443-455, 2016.
- Arivett, B. A., S. E. Fiester, E. J. Ohneck, W. F. Penwell, C. M. Kaufman, R. F. Relich and L. A. Actis. Antimicrobial activity of gallium protoporphyrin IX against Acinetobacter baumannii strains displaying different antibiotic resistance phenotypes. Antimicrobial Agent and Chemotherapy, 59, 7657-7665, 2015.
- Lopez, C., B. A. Arivett, L. A. Actis and M. E. Tolmasky. Inhibition of AAC(6’)-Ib-mediated resistance to amikacin in Acinetobacter baumannii by an antisense peptide-conjugated 2’4’-bridge nucleic acid (BNA)/DNA hybrid oligomer. Antimicrobial Agent and Chemotherapy, 59, 5798-5802, 2015.
- Penwell, W. F., N. DeGrace, S. Tentarelli, L. Gauthier, C. Gilbert, B. A. Arivett, A. Miller, T. Durand-Reville, C. Joubran, and L. A. Actis. Discovery and characterization of novel hydroxamate siderophores, baumannoferrin A and B, produced by Acinetobacter baumannii. ChemBioChem, 16, 1896-1904, 2015.
- Pope, W. H., C. A. Bowman, D. A. Russell, D. Jacobs-Sera, D. J. Asai, S. G. Cresawn, W. R. Jacobs, R. W. Hendrix, J. G. Lawrence, G. F. Hatfull; Science Education Alliance Phage Hunters Advancing Genomics and Evolutionary Science; Phage Hunters Integrating Research and Education; Mycobacterial Genetics Course. Whole genome comparison of a large collection of mycobacteriophages reveals a continuum of phage genetic diversity. Elife, 4:e06416, 2015.
- Harding, C. M., M. A. Nasr, R. L. Kinsella, N. E. Scott, L. J. Foster, B. S. Weber, S. E. Fiester, L. A. Actis, R. S. Munson, Jr, and M. F. Feldman. Acinetobacter strains carry two functional oligosaccharyltransferases, one devoted exclusively to type IV pilin, and the other one dedicated to O-glycosylation of multiple proteins. Molecular Microbiology, 96, 1023-1041, 2015.
- Arivett, B., S. Fiester, D. Ream, D. Centrón, M. S. Ramirez, M. Tolmasky, and L. Actis. Draft genome of the multidrug-resistant Acinetobacter baumannii A155 clinical isolate. Genome Announcements, 3, e00212-15, 2015.
- Fiester, S. E., C. C. Nwugo, W. F. Penwell, J. M. Neary, A. C. Beckett, B. A. Arivett, R. E. Schmidt, S. C. Geiger, P. L. Connerly, S. M. Menke, A. P. Tomaras, and Luis A. Actis. Role of the carboxy terminus of SecA in iron acquisition, protein translocation, and virulence of the bacterial pathogen Acinetobacter baumannii. Infection and Immunity, 83, 1354-1365, 2015.
- Arivett, B. A, D. C. Ream, S. E. Fiester, K. Mende, C. K. Murray, M. G. Thompson, S. Kanduru, A. M. Summers, A. L. Roth, D. V. Zurawski, and L. A. Actis. Draft genome sequences of Klebsiella pneumoniae clinical type strain ATCC 13883 and three multidrug-resistant clinical isolates. Genome Announcements, 3, e01385-14, 2015.
- Mussi, M. A., L. A. Actis, D. de Mendoza, L. E. Cybulski. Using a microbial physiologic and genetic approach to investigate how bacteria sense physical stimuli. Biochemistry and Molecular Biology Education, 42, 427-434, 2014.
- Jacobs, A., M. Thompson, C. Black, J. Kessler, L. Clark, C. McQueary, H. Gancz, J. Moon, Y. Si, M. Owen, J. Hallock, Y. Kwak, A. Summers, C. Li, D. Rasko, W. Penwell, C. Honnold, M. Wise, P. Waterman, E. Lesho, R. Stewart, L. A. Actis, T. Palys, D. Craft and D. Zurawski. AB5075, a highly virulent isolate of Acinetobacter baumannii, as a model strain for the evaluation of pathogenesis and antimicrobial treatments. mBio, 5, e01076-14, 2014.
- Harding, C. M., E. N. Tracy, M. Carruthers, P. N. Rather, L. A. Actis and R. S. Munson, Jr. Demonstration of type IV pili production by Acinetobacter baumannii and their role in natural transformation, twitching motility and surface-associated motility. mBio, 4, e00360-13, 2013.
- Zimbler, D. L., B. A. Arivett, A. C. Beckett, S. M. Menke and L. A. Actis. Functional features of TonB energy transduction systems of Acinetobacter baumannii. Infection and Immunity, 81, 3382-3394, 2013.
- Naka, H, L. A. Actis and J. H. Crosa. The anguibactin biosynthesis and transport genes are encoded in the chromosome of Vibrio harveyi: a possible evolutionary origin for the pJM1 plasmid-encoded system of Vibrio anguillarum? MicrobiologyOpen, 2, 182-194, 2013.
- Golic, A., M. Vaneechoutte, A. Nemec, A. M. Viale, L. A. Actis and M. A. Mussi. Staring at the cold sun: blue light regulation is distributed within the genus Acinetobacter. Plos One, 8, e55059, 2013.
- Nwugo, C. C., B. A. Arivett, D. L. Zimbler, J. A. Gaddy, A. M. Richards, and L. A. Actis. Effect of ethanol on differential protein production and expression of potential virulence functions in the opportunistic pathogen Acinetobacter baumannii. Plos One, 7, e51936, 2012.
- Thompson, R. J., B G. Bobay, S. D. Stowe, A. L. Olson, L. Peng, Z. Su, L. A. Actis, C. C. Melander and J. Cavanagh. Identification of BfmR, a response regulator involved in biofilm development, as a target for a 2-aminoimidazole-based anti-biofilm agent. Biochemistry, 51, 9776–9778, 2012.
- McQueary, C. N., B. C. Kirkup, Y. Si, M. Barlow, L. A. Actis, D. W. Craft, and D. V. Zurawski. Extracellular stress and lipopolysaccharide modulate Acinetobacter baumannii surface-associated motility. The Journal of Microbiology, 50, 434-443, 2012.
- Penwell, W. F., B. A. Arivett and L. A. Actis. The Acinetobacter baumannii entA gene located outside the acinetobactin cluster is critical for siderophore production, iron acquisition and virulence. Plos One, 7, e36493, 2012.
- Zimbler, D. L., T. M. Park, B. A. Arivett, W. F. Penwell, S. M. Greer, T. M. Woodruff, D. L. Tierney and L. A. Actis. Stress response and virulence functions of the A. baumannii NfuA Fe-S scaffold protein. Journal of Bacteriology, 194, 2884-2893, 2012.
- Gaddy J. A., B. A. Arivett, M. McConnell, R. López-Rojas, J. J. Pachón, and L. A. Actis. Role of acinetobactin-mediated iron acquisition functions in the interaction of Acinetobacter baumannii ATCC 19606T with human lung epithelial cells, Galleria mellonella caterpillars and mice. Infection and Immunity, 80,1015-1024, 2012.
- Mussi, M. A., A. S. Limansky, V. Relling, P. Ravasi, A. Arakaki, L. A. Actis, and A. M. Viale. Horizontal gene transfer and assortative recombination within the Acinetobacter baumannii clinical population provide genetic diversity at the single carO gene, encoding a major outer membrane protein channel. Journal of Bacteriology, 193, 4736-4748, 2011.
- McQueary, C. N., and L. A. Actis. Acinetobacter baumannii biofilms: variations among strains and correlations with other cell properties. The Journal of Microbiology, 49, 243-250, 2011.
- Nwugo, C., J. A. Gaddy, D. L. Zimbler, and L. A. Actis. Deciphering the iron response in Acinetobacter baumannii: a proteomics approach. Journal of Proteomics, 74, 44-58, 2011.
- Mussi, A, J. A. Gaddy, M. Cabruja, B. A. Arivett, A. Viale, R. Rasia, and L. A. Actis. The opportunistic human pathogen Acinetobacter baumannii senses and responds to light. Journal of Bacteriology, 192, 6336-6345, 2010.
- Gaddy, J. A., A. P. Tomaras, and L. A. Actis. The Acinetobacter baumannii 19606 OmpA protein plays a role in biofilm formation on abiotic surfaces and the interaction of this pathogen with eukaryotic cells. Infection and Immunity, 77, 3150-3160, 2009.
- Anna de Breij, A., J. Gaddy, J. van der Meer, R. Koning, A. Koster, P. van den Broek, L. Actis, P. Nibbering, and L. Dijkshoorn. CsuA/BABCDE-dependent pili are not involved in the adherence of Acinetobacter baumannii ATCC19606T to human airway epithelial cells and their inflammatory response. Research in Microbiology, 160, 213-218, 2009.
- Tomaras, A. P., M. J. Flagler, C. W. Dorsey, J. A. Gaddy, and L. A. Actis. Characterization of a two-component regulatory system from Acinetobacter baumannii that controls biofilm formation and cellular morphology. Microbiology, 154, 3398-3409, 2008.
- Birshan, D., A. J. C. Soler Bistué, A. P. Tomaras, M. Dandekar, T. Tran, J. Newmark, D. Bui, N. Gupta, K. Hernandez, R. Sarno, A. Zorreguieta, L. A. Actis, and M. E. Tolmasky. Complete nucleotide sequence of the Klebsiella pneumoniae multiresistance plasmid pMET1: similarity with the Yersinia pestis plasmid pCRY and integrative conjugative elements. PLoS ONE Microbiology, 3, e1800, 2008.
- Rodríguez-Baño, J., S. Soto, J. M. Cisneros, J. Pachón, A. Pascual, L. Martínez-Martínez, C. McQueary, L. A. Actis, J. Vila, and the Spanish Group for the Study of Nosocomial Infections (GEIH). Biofilm formation in Acinetobacter baumannii: associated features and clinical implications. Clinical Microbiology and Infection, 14, 276-278, 2008.
- Rhodes, E. R., C. J. Shoemaker, S. M. Menke, R. E. Edelmann, and L. A. Actis. Evaluation of different iron sources and their influence in biofilm formation by the dental pathogen Actinobacillus actinomycetemcomitans. Journal of Medical Microbiology, 56, 119-128, 2007.
- Dorsey, C. W., A. P, Tomaras, and L. A. Actis. Sequence and organization of pMAC, an Acinetobacter baumannii plasmid harboring genes involved in organic peroxide resistance. Plasmid, 56, 112-123, 2006.
- McGillivary, G., L. M. Smoot, and L. A. Actis. Characterization of the IgA1 protease from the Brazilian purpuric fever strain F3031 of Haemophilus influenzae biogroup aegyptius. FEMS Microbiology Letters, 250, 229-236, 2005.
- Rhodes, E. R., A. P. Tomaras, G. McGillivary, P. L. Connerly, and L. A. Actis. Genetic and functional analysis of the Actinobacillus actinomycetemcomitans AfeABCD siderophore independent iron-acquisition system. Infection and Immunity 73, 3758-3763, 2005.
- McGillivary, G., A. P. Tomaras, E. R. Rhodes, and L. A. Actis. Cloning and sequencing of a genomic island found in the Brazilian purpuric fever clone of Haemophilus influenzae biogroup aegyptius. Infection and Immunity, 73, 1927-1938, 2005.
- Dorsey, C. W., A. P, Tomaras, P. L. Connerly, M. E. Tolmasky, J. H. Crosa, and L. A. Actis. The siderophore-mediated iron acquisition systems of Acinetobacter baumannii ATCC 19606 and Vibrio anguillarum 775 are structurally and functionally related. Microbiology, 150, 3657-3667, 2004.
- Dorsey, C. W., and L. A. Actis. Analysis of pVU3695, a plasmid encoding glutathione-dependent formaldehyde dehydrogenase activity and formaldehyde resistance in the Escherichia coli VU3695 clinical strain. Plasmid, 51, 116-126, 2004.
- Actis, L. A, E. Rhodes, and A. Tomaras. Genetic and molecular characterization of a dental pathogen using genome-wide approaches. Advances in Dental Research, 17, 95-99, 2003.
- Tomaras, A. P., C. W. Dorsey, R. E. Edelmann, and L. A. Actis. Attachment to and biofilm formation on abiotic surfaces by Acinetobacter baumannii: involvement of a novel chaperone-usher pili assembly system. Microbiology, 149, 3461-3484, 2003.
- Di Lorenzo, M., M. Stork, M. E. Tolmasky, L. A. Actis, D. Farrell, T. J. Welch, L. M. Crosa, A. M. Wertheimer, Q. Chen, P. Salinas, L. Waldbeser, and J. H. Crosa. The complete sequence of the virulence plasmid pJM1 from the marine fish pathogen Vibrio anguillarum strain 775. Journal of Bacteriology, 185, 5822-5830, 2003.
- Dorsey, C. W., M. S. Beglin, and L. A. Actis. Detection and expression analysis of iron-uptake components in Acinetobacter baumannii clinical isolates. Journal of Clinical Microbiology, 41, 4188-4193, 2003.
- Dorsey, C. W., M. E. Tolmasky, J. H. Crosa, and L. A. Actis. Genetic organization of an Acinetobacter baumannii chromosomal region harbouring genes related to siderophore biosynthesis and transport. Microbiology, 149, 1227-1238, 2003.
- Dorsey, C. W., A. P. Tomaras, and L. A. Actis. Genetic and phenotypic analysis of Acinetobacter baumannii insertion derivatives generated with a Transposome system. Applied and Environmental Microbiology, 68, 6353-6360, 2002.
- Sarong, R., G. McGillivary, D. Serrate, L. A. Actis, and M. E. Tolmasky. Complete nucleotide sequence of Klebsiella pneumoniae multiresistance plasmid pJHCMW1. Antimicrobial Agents and Chemotherapy, 46, 3422-3427, 2002.
- Smoot, L. M., D. D. Franke, G. McGillivary, and L. A. Actis. Genomic analysis of the F3031 Brazilian purpuric fever clone of Haemophilus influenzae biogroup aegyptius by PCR-based subtractive hybridization. Infection and Immunity, 70, 2694-2699, 2002.
- Echenique, J. R., C. W. Dorsey, L. C. Patrito, A. Petroni, M. E. Tolmasky, and L. A. Actis. Acinetobacter baumannii has two genes encoding glutathione-dependent formaldehyde dehydrogenase: evidence for differential regulation in response to iron. Microbiology, 147, 2805-2815, 2001.
- Nudel, C., R. Gonzalez, N. Castañeda, G. Mahler, and L. A. Actis. Influence of iron on growth, production of siderophore compounds, membrane proteins, and lipase activity in Acinetobacter calcoaceticus BD413. Microbiological Research, 155, 263-269, 2001.
- Wertheimer, A. M., W. Verweij, Q. Chen, L. M. Crosa, M. Nagasawa, M. E. Tolmasky, L. A. Actis, and J. H. Crosa. Characterization of the angR gene of the fish pathogen Vibrio anguillarum: essential role in virulence. Infection and Immunity, 67, 6496-6509, 1999.
- Actis, L. A., J. C. Smoot, C. E. Barancin, and R. H. Findlay. Comparison of differential plating media and two chromatography techniques for the detection of histamine production in bacteria. Journal of Microbiological Methods, 39, 79-90, 1999.
- Bidinost, C., P. J. Wilderman, C. Dorsey, and L. A. Actis. Analysis of the replication elements of the pMJ101 plasmid from the fish pathogen Vibrio ordalii. Plasmid, 42, 20-30, 1999.
- Smoot. L. M., E. C. Bell, J. H. Crosa, and L. A. Actis. Detection of Fur and iron transport proteins in the Brazilian purpuric fever clone of Haemophilus influenzae biogroup aegyptius. Journal of Medical Microbiology, 48, 629-636, 1999.
- Graber, K. R., L. M. Smoot, and L. A. Actis. Expression of iron binding proteins and hemin binding activity in the dental pathogen Actinobacillus actinomycetemcomitans. FEMS Microbiology Letters, 163, 135-142, 1998.
- Barancin C. E., J. C. Smoot, R. H. Findlay, and L. A. Actis. Plasmid-mediated histamine biosynthesis in the bacterial fish pathogen Vibrio anguillarum. Plasmid, 39, 235-244, 1998.
- Actis, L. A., M. E. Tolmasky, L. M. Crosa, and J. H. Crosa. Characterization and regulation of the expression of FatB, an iron transport protein encoded by the pJM1 virulence plasmid. Molecular Microbiology, 17, 197-204, 1995.
- Tolmasky, M. E., L. A. Actis, and J. H. Crosa. A histidine decarboxylase gene encoded by the Vibrio anguillarum plasmid pJM1: histamine is a precursor in the biosynthesis of anguibactin. Molecular Microbiology, 15, 87-95, 1994.
- Wertheimer, A. M., M. E. Tolmasky, L. A. Actis, and J. H. Crosa. Structural and functional analyses of mutant Fur proteins with impaired regulatory function. Journal of Bacteriology, 176, 5116-5122, 1994.
- Chen, Q., L. A. Actis, M. E. Tolmasky, and J. H. Crosa. Chromosome-mediated 2,3-dihydroxybenzoic acid is a precursor in the biosynthesis of the plasmid-mediated siderophore anguibactin in Vibrio anguillarum. Journal of Bacteriology, 176, 4226-4234, 1994.
- Bidinost, C., J. H. Crosa, and L. A. Actis. Localization and analysis of the replication region of the pMJ101 plasmid from Vibrio ordalii. Plasmid, 31, 2422-250, 1994.
- Tolmasky, M. E., A. M. Wertheimer, L. A. Actis, and J. H. Crosa. Characterization of the Vibrio anguillarum fur gene: role in regulation of expression of the FatA outer membrane protein and catechols. Journal of Bacteriology, 176, 213-220, 1994.
- Actis, L. A., M. E. Tolmasky, L. M. Crosa, and J. H. Crosa. Effect of iron-limiting conditions on growth of clinical isolates of Acinetobacter baumannii. Journal of Clinical Microbiology, 31, 2812-2815,1993.
- Tolmasky, M. E., L. A. Actis, and J. H. Crosa. A single amino acid change in AngR, a protein encoded by virulence pJM1-like plasmids, results in hyperproduction of anguibactin. Infection and Immunity, 61, 3228-3233, 1993.
- Waldbeser, L. S., M. E. Tolmasky, L. A. Actis, and J. H. Crosa. Mechanisms for negative regulation by iron of the fatA outer membrane protein gene expression in Vibrio anguillarum 775. Journal of Biological Chemistry, 268, 10433-10439, 1993.
- Echenique, J. R., H. Arienti, M. E. Tolmasky, R. R. Read, R. J. Staneloni, J. H. Crosa, and L. A. Actis. Characterization of a high affinity iron transport system in Acinetobacter baumannii. Journal of Bacteriology, 174, 7670-7679, 1992.
- Köster, W. L., L. A. Actis, L. Waldbeser, M. E, Tolmasky, and J. H. Crosa. Molecular characterization of the iron transport system mediated by the pJM1 plasmid in Vibrio anguillarum. Journal of Biological Chemistry, 266, 23829-23833, 1991.
- Genti-Raimondi, S., M. E. Tolmasky, Luis C. Patrito, A. Flury, and L. A. Actis. Molecular cloning and expression of the β-hydroxysteroid dehydrogenase gene from Pseudomonas testosteroni. Gene, 105, 43-49, 1991.
- Chamorro, R. M., L. A. Actis, J. H. Crosa, and M. E. Tolmasky. Dissemination of plasmid-mediated amikacin resistance among pathogenic Klebsiella pneumoniae. Medicina, 50, 543-547, 1990.
- Farrell, D. H., P. Mikesell, L. A. Actis, and J. H. Crosa. Amino acid sequence of the iron transport regulatory protein AngR from Vibrio anguillarum shows homology with DNA binding proteins. Gene, 86, 45-51, 1990.
- Jalal, M. A. F, M. B. Hossain, D. van der Helm, J. Sanders-Loehr, L. A. Actis, and J. H. Crosa. Structure of anguibactin, a unique plasmid-related bacterial siderophore from the fish pathogen Vibrio anguillarum. Journal of American Chemical Society, 111, 292-296, 1989.
- Hartstein, A. I., A. L. Rashad, J. M. Liebier, L. A. Actis, J. Freeman, J. W. Rourke, T. B. Stibolt, M. E. Tolmasky, G. R. Ellis, and J. H. Crosa. Multiple intensive care unit outbreak of Acinetobacter calcoaceticus subspecies anitratus respiratory infection and colonization associated with contaminated, reusable ventilator circuits and resuscitation bags. The American Journal of Medicine, 85, 624-631, 1989.
- Crosa, L. M., M. K. Wolf, L. A. Actis, J. Sanders-Loehr, and J. H. Crosa. New aerobactin-mediated iron uptake system in a septicemia-causing strain of Enterobacter cloacae. Journal of Bacteriology, 170, 5539-5544, 1988.
- Tolmasky, M. E., P. Salinas, L. A. Actis, and J. H. Crosa. Enhanced production of siderophore activity mediated by pJM1-like plasmids in Vibrio anguillarum. Infection and Immunity, 56, 1608-1614, 1988.
- Tolmasky, M. E., L. A. Actis, and J. H. Crosa. Genetic analysis of the iron uptake region of the Vibrio anguillarum plasmid pJM1: Molecular cloning of genetic determinants encoding a novel transactivator of siderophore biosynthesis. Journal of Bacteriology, 170, 1913-1919, 1988.
- Actis, L. A., M. E. Tolmasky, D. H. Farrell, and J. H. Crosa. Genetic and molecular characterization of essential components of the Vibrio anguillarum plasmid-mediated iron-transport system. Journal of Biological Chemistry, 263, 2853-2860, 1988.
- Bocco, J. L., L. A. Actis, A. Flury, and L. C. Patrito. Identification and molecular weight of SP1 synthesized from mRNA of human placenta in a wheat germ cell-free system. Molecular Biology Reports, 12, 55-59, 1987.
- Actis, L. A., W. Fish, J. H. Crosa, K. Kellerman, S. E. Ellenberger, F. Hauser, and J. Sanders-Loehr. Characterization of anguibactin, a novel siderophore from Vibrio anguillarum 775 (pJM1). Journal of Bacteriology, 167, 57-65, 1986.
- Roberts, M. E., L. A. Actis, and J. H. Crosa. Molecular characterization of chloramphenicol resistant Haemophilus parainfluenzae and Haemophilus ducreyi. Antimicrobial Agents and Chemotherapy, 28, 176-180, 1985.
- Tolmasky, M. E., L. A. Actis, A. E. Toranzo, J. L. Barja, and J. H. Crosa. Plasmid-mediated iron uptake system in Vibrio anguillarum strains from turbot in Spain. Journal of General Microbiology, 131, 1987-1997, 1985.
- Actis, L. A., S. A. Potter, and J. H. Crosa. The iron-regulated outer membrane protein OM2 of Vibrio anguillarum is encoded by the virulence plasmid pJM1. Journal of Bacteriology, 161, 736-742, 1985.
- Actis, L. A., A. Flury, and L. C. Patrito. Translation in cell-free system of mRNA from term placenta extracted by guanidine hydrochloride. Molecular Biology Reports, 9, 203-208, 1983.
- Actis, L. A., M. A. Vides, A. Flury, and L. C. Patrito. Molecular characterization of pregnancy specific beta1-glycoprotein synthesized from human placenta. Cellular and Molecular Biology, 27, 97-104, 1981.
- Actis, L. A., L. C. Patrito, A. Flury, and M. A. Vides. Identification of pregnancy specific beta1-glycoprotein in the plasma of man with choriocarcinoma. Cellular and Molecular Biology, 24, 337-340, 1979.
Work in Progress
Characterization of cellular and molecular mechanisms involved in the capacity of Acinetobacter baumanni to sense and respond to illumination at different temperatures.