Philippos Tsourkas

Dr. Philippos Tsourkas

orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
Verified
Journal Article
Open access
PDF file
ASAlicia Salisbury
Alicia Salisbury
PTPhilippos Tsourkas
Philippos Tsourkas
Bacteriophages are the most numerous entities on Earth. The number of sequenced phage genomes is approximately 8000 and increasing rapidly. Sequencing of a genome is followed by annotation, where genes, start codons, and functions are putatively identified. The mainstays of phage genome annotation are auto-annotation programs such as Glimmer and GeneMark. Due to the relatively small size of phage genomes, many groups choose to manually curate auto-annotation results to increase accuracy. An additional benefit of manual curation of auto-annotated phage genomes is that the process is amenable to be performed by students, and has been shown to improve student recruitment to the sciences. However, despite its greater accuracy and pedagogical value, manual curation suffers from high labor cost, lack of standardization and a degree of subjectivity in decision making, and susceptibility to mistakes. Here, we present a method developed in our lab that is designed to produce accurate annotations while reducing subjectivity and providing a degree of standardization in decision-making. We show that our method produces genome annotations more accurate than auto-annotation programs while retaining the pedagogical benefits of manual genome curation.

1 June 2007 in Biophysical Journal
Verified
Journal Article
Closed access
PDF file
PTPhilippos Tsourkas
Philippos Tsourkas
NBNicole Baumgarth
Nicole Baumgarth
SSScott I. Simon
Scott I. Simon
SRSubhadip Raychaudhuri
Subhadip Raychaudhuri

2 January 2016 in Bacteriophage
Verified
Journal Article
Open access
DYDiane G. Yost
Diane G. Yost
PTPhilippos Tsourkas
Philippos Tsourkas
PAPenny S. Amy
Penny S. Amy
American Foulbrood Disease (AFB) is an infection of honeybees caused by the bacterium Paenibacillus larvae. One potential remedy involves using biocontrol, such as bacteriophages (phages) to lyse P. larvae. Therefore, bacteriophages specific for P. larvae were isolated to determine their efficacy in lysing P. larvae cells. Samples from soil, beehive materials, cosmetics, and lysogenized P. larvae strains were screened; of 157 total samples, 28 were positive for at least one P. larvae bacteriophage, with a total of 30. Newly isolated bacteriophages were tested for the ability to lyse each of 11 P. larvae strains. Electron microscopy demonstrated that the phage isolates were from the family Siphoviridae. Seven phages with the broadest host ranges were combined into a cocktail for use in experimental treatments of infected bee larvae; both prophylactic and post-infection treatments were conducted. Results indicated that although both pre- and post-treatments were effective, prophylactic administration of the phages increased the survival of larvae more than post-treatment experiments. These preliminary experiments demonstrate the likelihood that phage therapy could be an effective method to control AFB.

19 July 2018 in Viruses
Verified
Journal Article
Open access
PDF file
CSCasey Stamereilers
Casey Stamereilers
CFChristopher Fajardo
Christopher Fajardo
JWJamison K. Walker
Jamison K. Walker
KMKatterinne N. Mendez
Katterinne N. Mendez
ECEduardo Castro-Nallar
Eduardo Castro-Nallar
PTPhilippos Tsourkas
Philippos Tsourkas
The antibiotic-resistant bacterium Paenibacillus larvae is the causative agent of American foulbrood (AFB), currently the most destructive bacterial disease in honeybees. Phages that infect P. larvae were isolated as early as the 1950s, but it is only in recent years that P. larvae phage genomes have been sequenced and annotated. In this study we analyze the genomes of all 48 currently sequenced P. larvae phage genomes and classify them into four clusters and a singleton. The majority of P. larvae phage genomes are in the 38–45 kbp range and use the cohesive ends (cos) DNA-packaging strategy, while a minority have genomes in the 50–55 kbp range that use the direct terminal repeat (DTR) DNA-packaging strategy. The DTR phages form a distinct cluster, while the cos phages form three clusters and a singleton. Putative functions were identified for about half of all phage proteins. Structural and assembly proteins are located at the front of the genome and tend to be conserved within clusters, whereas regulatory and replication proteins are located in the middle and rear of the genome and are not conserved, even within clusters. All P. larvae phage genomes contain a conserved N-acetylmuramoyl-l-alanine amidase that serves as an endolysin.

12 September 2011 in Cellular & Molecular Immunology
Verified
Journal Article
Closed access
PTPhilippos Tsourkas
Philippos Tsourkas
WLWanli Liu
Wanli Liu
SDSomkanya C Das
Somkanya C Das
SPSusan K Pierce
Susan K Pierce
SRSubhadip Raychaudhuri
Subhadip Raychaudhuri

1 August 2008 in Biophysical Journal
Verified
Journal Article
Closed access
PDF file
PTPhilippos Tsourkas
Philippos Tsourkas
MLMarjorie L. Longo
Marjorie L. Longo
SRSubhadip Raychaudhuri
Subhadip Raychaudhuri