Virology Commons^™

A Single Vertebrate Dna Virus Protein Disarms Invertebrate Immunity To Rna Virus Infection, Don B. Gammon, Sophie Duraffour, Daniel K. Rozelle, Heidi Hehnly, Rita Sharma, Michael E. Sparks, Cara C. West, Ying Chen, James J. Moresco, Graciela Andrei, John H. Connor, Darryl Conte Jr., Dawn E. Gundersen-Rindal, William L. Marshall, John R. Yates, Neal S. Silverman, Craig C. Mello

Neal Silverman

Virus-host interactions drive a remarkable diversity of immune responses and countermeasures. We found that two RNA viruses with broad host ranges, vesicular stomatitis virus (VSV) and Sindbis virus (SINV), are completely restricted in their replication after entry into Lepidopteran cells. This restriction is overcome when cells are co-infected with vaccinia virus (VACV), a vertebrate DNA virus. Using RNAi screening, we show that Lepidopteran RNAi, Nuclear Factor-kappaB, and ubiquitin-proteasome pathways restrict RNA virus infection. Surprisingly, a highly conserved, uncharacterized VACV protein, A51R, can partially overcome this virus restriction. We show that A51R is also critical for VACV replication in vertebrate cells …

The Phenotypic Effects And Transcript Response Of Salt Stress, The Impact Of Viral Infection On Salt Stress Symptoms, And The Effect Of Salt Stress On Soybean Virus Vector Activity In Soybean Varieties That Vary In Chloride Uptake, Alma Glenn Laney

Graduate Theses and Dissertations

With the increase in saline soils worldwide, understanding the mechanisms for salt tolerance in plants is important to reduce yield loss due to salt stress. Soybean, Glycine max (L.) Merr., genotypes differ in chloride uptake with genotypes that take up chloride into foliar tissues tending to be salt-sensitive whereas those that partially exclude chloride from the leaves are more salt-tolerant. Transcriptional and physiological responses were measured in two soybean cultivars, Clark and Manokin, which differ in chloride uptake in response to salt stress and in combination with Soybean mosaic virus (SMV) and its aphid vector, Aphis glycines . The interaction …

A Portable Impedance Biosensing System Based On A Laptop With Labview For Rapid Detection Of Avian Influenza Virus, Yixiang Wang

Graduate Theses and Dissertations

Avian Influenza Virus (AIV) H5N1 is a highly pathogenic virus found not only in birds but also in human. Rapid and sensitive detection method is needed to help prevent the spread of AIV H5N1. In this study, a portable impedance biosensing system based on a laptop with LabVIEW software was developed for detection of AIV H5N1. First, a virtual instrument was programmed with LabVIEW software to form a platform for impedance measurement, data processing and control. The audio card of a laptop was used as a function generator while a data acquisition card was used with the signal channels for …

Rnase L Interacts With Filamin A To Regulate Actin Dynamics And Barrier Function For Viral Entry, Krishnamurthy Malathi, Mohammad Adnan Siddiqui, Shubham Dayal, Merna Naji, Heather J, Ezelle, Chun Zeng, Aimin Zhou, Bret A. Hassel

Chemistry Faculty Publications

The actin cytoskeleton and its network of associated proteins constitute a physical barrier that viruses must circumvent to gain entry into cells for productive infection. The mechanisms by which the physical signals of infection are sensed by the host to activate an innate immune response are not well understood. The antiviral endoribonuclease RNase L is ubiquitously expressed in a latent form and activated upon binding 2-5A, a unique oligoadenylate produced during viral infections. We provide evidence that RNase L in its inactive form interacts with the actin-binding protein Filamin A to modulate the actin cytoskeleton and inhibit virus entry. Cells …

Structural Insights Into The Architecture Of The Hyperthermophilic Fusellovirus Ssv1, Kenneth M. Stedman, Melissa Deyoung, Mitul Saha, Michael B. Sherman, Marc C. Morais

Biology Faculty Publications and Presentations

The structure and assembly of many icosahedral and helical viruses are well-characterized. However, the molecular basis for the unique spindle-shaped morphology of many viruses that infect Archaea remains unknown. To understand the architecture and assembly of these viruses, the spindle-shaped virus SSV1 was examined using cryo-EM, providing the first 3D-structure of a spindle-shaped virus as well as insight into SSV1 biology, assembly and evolution. Furthermore, a geometric framework underlying the distinct spindle-shaped structure is proposed.

Chlorovirus Atcv-1 Is Part Of The Human Oropharyngeal Virome And Is Associated With Changes In Cognitive Functions In Humans And Mice, Lorraine Jones-Brando Ph. D., Robert H. Yolken M. D., David D. Dunigan Ph. D.

David D Dunigan Ph. D.

Chloroviruses (family Phycodnaviridae) are large DNA viruses known to infect certain eukaryotic green algae and have not been previously shown to infect humans or to be part of the human virome. We unexpectedly found sequences homologous to the chlorovirus Acanthocystis turfacea chlorella virus 1 (ATCV-1) in a metagenomic analysis of DNA extracted from human oropharyngeal samples. These samples were obtained by throat swabs of adults without a psychiatric disorder or serious physical illness who were participating in a study that included measures of cognitive functioning. The presence of ATCV-1 DNA was confirmed by quantitative PCR with ATCV-1 DNA being documented …

Enhanced Expression Of Codon Optimized Mycobacterium Avium Subsp. Paratuberculosis Antigens In Lactobacillus Salivarius, Christopher D. Johnston, John P. Bannatine, Rodney Govender, Lorraine Endersen, Daniel Pletzer, Helge Weingart, Aidan Coffey, Jim O'Mahony, Roy D. Sleator

Department of Biological Sciences Publications

It is well documented that open reading frames containing high GC content show poor expression in A+T rich hosts. Specifically, G+C-rich codon usage is a limiting factor in heterologous expression of Mycobacterium avium subsp. paratuberculosis (MAP) proteins using Lactobacillus salivarius. However, re-engineering opening reading frames through synonymous substitutions can offset codon bias and greatly enhance MAP protein production in this host. In this report, we demonstrate that codon-usage manipulation of MAP2121c can enhance the heterologous expression of the major membrane protein (MMP), analogous to the form in which it is produced natively by MAP bacilli. When heterologously over-expressed, antigenic determinants …

Imaging Luciferase-Expressing Viruses, Michael A. Barry, Shannon May, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

Optical imaging of luciferage gene expression has become a powerful tool to track cells and viruses in vivo in small animal models. Luciferase imaging has been used to study the location of infection by replication-defective and replication-competent viruses and to track changes in the distribution of viruses in mouse models. This approach has also been used in oncolytic studies as a non-invasive means to monitor the growth and killing of tumor cells modified with luciferase genes. In this chapter, we describe the techniques used for luciferase imaging as have been applied to track replication-defective and replication-competent adenoviruses in mouse and …

Dengue Viral Rna Levels In Peripheral Blood Mononuclear Cells Are Associated With Disease Severity And Preexisting Dengue Immune Status, Anon Srikiatkhachorn, Sineewanlaya Wichit, Robert V. Gibbons, Sharone Green, Daniel H. Libraty, Timothy P. Endy, Francis A. Ennis, Siripen Kalayanarooj, Alan L. Rothman

Alan Rothman

BACKGROUND: Infection with dengue viruses (DENV) causes a wide range of manifestations from asymptomatic infection to a febrile illness called dengue fever (DF), to dengue hemorrhagic fever (DHF). The in vivo targets of DENV and the relation between the viral burden in these cells and disease severity are not known.

METHOD: The levels of positive and negative strand viral RNA in peripheral blood monocytes, T/NK cells, and B cells and in plasma of DF and DHF cases were measured by quantitative RT-PCR.

RESULTS: Positive strand viral RNA was detected in monocytes, T/NK cells and B cells with the highest amounts …

Impedance Biosensors For The Rapid Detection Of Viral And Bacterial Pathogens Using Avian Influenza Virus Subtypes H5n1 And H7n2 And Escherichia Coli O157:H7 As Model Targets, Jacob David Lum

Graduate Theses and Dissertations

This research investigated impedance biosensors for the rapid detection of viral and bacterial pathogens using avian influenza virus (AIV) subtypes H5N1 and H7N2 and Escherichia coli O157:H7 as the model targets, which were chosen due to their impact on the agricultural and food industries. For the detection of AIV H7N2, a single stranded DNA aptamer was selected using systematic evolution of ligands by exponential enrichment (SELEX). The selected aptamer and a previously selected aptamer against AIV H5N1 were used in a microfluidics chip with an embedded interdigitated array microelectrode to fabricate an impedance biosensor for specific detection of AIV H7N2 …

Antiviral Responses In Mouse Embryonic Stem Cells: Differential Development Of Cellular Mechanisms In Type I Interferon Production And Response, Ruoxing Wang

Dissertations

Embryonic stem cells (ESCs) have been recognized as a promising cell source for regenerative medicine. Intensive research over the past decade has led to the possibility that ESC-derived cells will be used for the treatment of human diseases. However, increasing evidence indicates that ESC-derived cells generated by the current differentiation methods are not fully functional. It is recently recognized that ESC-derived cells lack innate immunity to a wide range of infectious agents and inflammatory cytokines. When used in patients, ESC-derived cells would be placed in wounded sites that are exposed to various pathogens and inflammatory cytokines; therefore, their viability and …

Genomic Predictors Of Drug Response To The Alpha-Specific Phosphoinositol 3-Kinase (Pi3ka-Alpha) Inhibitor Byl719 In Head And Neck Cancers, Giananthony T. Rizzo

Electronic Thesis and Dissertation Repository

PIK3CA is the only frequently mutated, druggable oncogene in head and neck squamous cell cancer (HNSCC), with PIK3CA point mutations and gene amplification rates of 17.5% and 40% respectively, with higher rates in HPV-positive disease. The objective of this research was to determine the effects of BYL719, an α-specific PI3K inhibitor in HNSCC cell lines.

All cell lines with PIK3CA hotspot point mutations or gene amplifications will be sensitive to BYL719.

Twenty-eight HNSCC cell lines were subjected to increasing concentrations of BYL719 and cell viability was measured over time. Cell lines were screened for activating PIK3CA hotspot mutations and amplifications …

Investigating The Diversity Of Single-Stranded Dna Bacteriophages In Marine Environments, Max Stephen Hopkins

USF Tampa Graduate Theses and Dissertations

There are estimated to be 1030 virus-like particles in the world's oceans. Most are viruses that infect bacteria, called `bacteriophages' or simply `phages'. Phages exert tremendous influence on marine biogeochemical cycling because they are responsible for about half of all bacterial death in the oceans, causing nutrient release into the dissolved and particulate organic matter pools. Traditional paradigms of phage biology held that most of these ocean phages belonged to the Caudovirales group: phages that contain a double-stranded DNA genome within a geometric capsid `head' to which a `tail' is joined, in one of several morphological variants, that is the …

Intrinsic Innate Immunity Fails To Control Herpes Simplex Virus And Vesicular Stomatitis Virus Replication In Sensory Neurons And Fibroblasts, Pamela C. Rosato, David A. Leib

Dartmouth Scholarship

Herpes simplex virus 1 (HSV-1) establishes lifelong latent infections in the sensory neurons of the trigeminal ganglia (TG), wherein it retains the capacity to reactivate. The interferon (IFN)-driven antiviral response is critical for the control of HSV-1 acute replication. We therefore sought to further investigate this response in TG neurons cultured from adult mice deficient in a variety of IFN signaling components. Parallel experiments were also performed in fibroblasts isolated concurrently. We showed that HSV-1 replication was comparable in wild-type (WT) and IFN signaling-deficient neurons and fibroblasts. Unexpectedly, a similar pattern was observed for the IFN-sensitive vesicular stomatitis virus (VSV). …

Host Species Restriction Of Middle East Respiratory Syndrome Coronavirus Through Its Receptor, Dipeptidyl Peptidase 4, Neeltje Van Doremalen, Kerri L. Miazgowicz, Shauna Milne-Price, Trenton Bushmaker, Shelly Robertson, Dana Scott, Joerg Kinne, Jason S. Mclellan

Dartmouth Scholarship

Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in 2012. Recently, the MERS-CoV receptor dipeptidyl peptidase 4 (DPP4) was identified and the specific interaction of the receptor-binding domain (RBD) of MERS-CoV spike protein and DPP4 was determined by crystallography. Animal studies identified rhesus macaques but not hamsters, ferrets, or mice to be susceptible for MERS-CoV. Here, we investigated the role of DPP4 in this observed species tropism. Cell lines of human and nonhuman primate origin were permissive of MERS-CoV, whereas hamster, ferret, or mouse cell lines were not, despite the presence of DPP4. Expression of human DPP4 in nonsusceptible BHK and …

Structure And Function In Bacteriophage Phi6, James Carpino

Dissertations, Theses, and Capstone Projects

The present study of bacteriophage Phi6 has been preceded by a great number of exploratory studies of its structure and function, and these studies have formed a basis for Phi6's development into a model organism. In this study, two aspects of the model organism have been examined. 1. There are several uncharacterized and presumed untranslated regions (UTRs) in Phi6's 13.3 kilobase-pair dsRNA genome. I examined the impact of specific modification to the 3' UTR of the small segment of bacteriophage Phi6. I determined that modification to the purported UTR of the small segment resulted in severe fitness costs, supporting a …

Chlorovirus Skp1 And Core Ankyrin-Repeat Protein Interplay And Mimicry Of Cellular Ubiquitin Ligase Machinery, Eric Andrew Noel

School of Biological Sciences: Dissertations, Theses, and Student Research

The ubiquitin-proteasome system is a common target of several unrelated viruses that have evolved convergent strategies to redirect host ubiquitin machinery to serve their own needs. Members of the genus Chlorovirus, a group of large dsDNA viruses that infect certain freshwater chlorella-like green algae, encode a conserved Skp1 homolog and ankyrin-repeat (ANK) proteins, some of which contain C-terminal domains characteristic of cellular F-boxes or related viral PRANC domains. These observations suggested that this unique combination of chlorovirus proteins either interact with or imitate the key components of the SCF (Skp1-Cul1-F-box) ubiquitin ligases. Using mass spectrometry, we identified two functional …

Marine Viral Diversity And Spatiotemporal Variability, Dawn Goldsmith

USF Tampa Graduate Theses and Dissertations

Marine viruses are the most numerous biological entities in the ocean, with an estimated abundance of 4 x 10³⁰. They merit study not only because of their sheer abundance, but also because of the role they play in the Earth's biogeochemical cycles. Viral lysis of bacteria redirects the flow of nutrients among marine microbes, which ultimately affects the efficiency of the biological pump. Viral diversity is important because most viruses are host-specific. In preying on a certain type of bacteria, viruses affect the diversity and structure of the bacterial community, leading to changes in carbon and nutrient flows. …

Genome-Wide Analysis Of The Variation In Host Genetics In Response To Experimental Challenges With Porcine Circovirus 2b, Taylor B. Engle

Department of Animal Science: Dissertations, Theses, and Student Research

Porcine circovirus is the primary causative agent responsible for inducing a group of associated diseases known as porcine circovirus associated diseases (PCVAD), which can have detrimental effects on production efficiency as well as lead to mortality. The variation in host genetics plays a role in the ability to initiate an effective immune response. The objective of this research was to identify major genetic variants and genes that influence immune response and PCVAD susceptibility. Commercial crossbred pigs (n=974) were experimentally infected with a PCV2b strain to analyze genetic sources of variation in PCVAD susceptibility. The strain used for experimental infection was …

Population Dynamics Of Triticum Mosaic Virus In Various Host Species, Melissa S. Bartels

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

It has been established that RNA viruses should be genetically diverse, due to the high error rate of their RNA-dependent RNA polymerases and the lack of proof-reading capabilities. Plant RNA viruses are not as genetically diverse as expected. Evolutionary factors, such as purifying selection and bottlenecks that favor genetic stability, might be affecting plant viral populations. Otherwise RNA virus populations, with their potential for extreme diversity, might acquire a lethal number of mutations leading to the collapse of the population.

Triticum mosaic virus (TriMV) populations maintained in a controlled greenhouse environment displayed genetic stability. The mutation frequency per nucleotide of …

Comparing Virus Ultrafiltration Of Bacteriophages With Filtration Of Minute Virus Of Mice, Kent Smith

Graduate Theses and Dissertations

Industrial production of protein therapeutics demand rigorous testing and clearance of viruses. The U.S. Food and Drug Administration dictate the purity of pharmaceuticals with regards to viral contamination. As this testing is time consuming and expensive using mammalian cells and viruses, bacteriophages may provide a faster and cheaper alternative for membrane filtration processes. We used ultrafiltration membranes to filter protein solutions with viruses. Two bacteriophages were tested against membranes with two different pore sizes. These membranes were then tested by inverting the membrane's orientation. Flux measurements and log virus removal data were taken. Flux and log virus removal were seen …

Cell Kinase Inhibitor Panel Reveals Multiple Targets To Prevent Replication Of Varicella-Zoster Virus, Bryan Egan Bunnell

Honors Capstone Projects - All

The alphaherpesvirus that causes chicken pox and shingles, varicella-zoster virus (VZV), infects skin fibroblasts and keratinocytes. These cells are typically quiescent and it is known that VZV manipulates their intracellular environment to activate MAPK signaling cascades, cell cycle regulators, and many transcription factors for its replication. We hypothesized that inhibition of cell kinases would prevent VZV replication and also elucidate which pathways are most important. We evaluated 80 kinase inhibitors for cytotoxicity and anti-proliferative effects on human foreskin fibroblasts, and then determined their antiviral efficacy against VZV-ORF9-Luc strain. Ten well-tolerated, potent kinase inhibitors whose targets are critical mediators of VZV …

Loss Of Cell Surface Agal During Catarrhine Evolution: Possible Implications For The Evolution Of Resistance To Viral Infections And For Oligocene Lineage Divergence, Idalia Aracely Rodriguez

Doctoral Dissertations

The divergence of the two superfamilies belonging to the Infraorder Catarrhini –Cercopithecoidea (Old World monkeys) and Hominoidea (apes, including humans) – is generally assumed to have occurred during the Oligocene, between 38 and 20 million years ago. Genetic studies indicate that this time period was one of active genetic evolution under strong purifying selection for catarrhine primates. This includes selective pressures on the glycoprotein galactosyltransferase 1 (GGTA1) gene and subsequent inactivation “clocked” at approximately 28 ma, possibly prior to the Cercopithecoidea/Hominoidea split. The GGTA1 gene codes for an a1,3 galactosyltransferase (GT) enzyme that synthesizes a terminal disaccharide, …

Study Of Virus Dynamics By Mathematical Models, Xiulan Lai

Electronic Thesis and Dissertation Repository

This thesis studies virus dynamics within host by mathematical models, and topics discussed include viral release strategies, viral spreading mechanism, and interaction of virus with the immune system.

Firstly, we propose a delay differential equation model with distributed delay to investigate the evolutionary competition between budding and lytic viral release strategies. We find that when antibody is not established, the dynamics of competition depends on the respective basic reproduction numbers of the two viruses. If the basic reproductive ratio of budding virus is greater than that of lytic virus and one, budding virus can survive. When antibody is established for …

Cd46-Mediated Transduction Of A Species D Adenovirus Vaccine Improves Mucosal Vaccine Efficacy, Zenaido T. Camacho, Michael A. Barry, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

The high levels of preexisting immunity against Adenovirus type 5 (Ad5) have deemed Ad5 unusable for translation as a human vaccine vector. Low seroprevalent alternative viral vectors may be less impacted by preexisting immunity, but they may also have significantly different phenotypes from that of Ad5. In this study we compare species D Ads (26, 28, and 48) to the species C Ad5. In vitro transduction studies show striking differences between the species C and D viruses. Most notably, Ad26 transduced human dendritic cells much more effectively than Ad5. In vivo imaging studies showed strikingly different transgene expression profiles. The …

Cluster M Mycobacteriophages Bongo, Pegleg, And Rey With Unusually Large Repertoires Of Trna Isotypes, Welkin H. Pope, Kirk R. Anders, Madison Baird, Charles A. Bowman, Michelle M. Boyle, Gregory W. Broussard, Tiffany Chow, Kari L. Clase, Shannon Cooper, Kathleen A. Cornely, Randall J. Dejong, Veronique A. Delesalle, Lisa Deng, David Dunbar, Nicholas P. Edgington, Christina M. Ferreira, Kathleen Weston Hafer, Grant A. Hartzog, J. Robert Hatherill, Lee E. Hughes, Khristina Ipapo, Greg P. Krukonis, Christopher G. Meier, Denise L. Monti, Matthew R. Olm, Shallee T. Page, Craig L. Peebles, Claire A. Rinehart, Michael R. Rubin, Daniel A. Russell, Erin R. Sanders, Morgan Schoer, Christopher D. Shaffer, James Wherley, Edwin Vazquez, Han Yuan, Daiyuan Zhang, Steven G. Cresawn, Deborah Jacobs-Sera, Roger W. Hendrix, Graham F. Hatfull

Chemistry & Biochemistry Faculty Publications

Genomic analysis of a large set of phages infecting the common host Mycobacterium smegmatis mc2155 shows that they span considerable genetic diversity. There are more than 20 distinct types that lack nucleotide similarity with each other, and there is considerable diversity within most of the groups. Three newly isolated temperate mycobacteriophages, Bongo, PegLeg, and Rey, constitute a new group (cluster M), with the closely related phages Bongo and PegLeg forming subcluster M1 and the more distantly related Rey forming subcluster M2. The cluster M mycobacteriophages have siphoviral morphologies with unusually long tails, are homoimmune, and have larger than average genomes …

Deep Rna Sequencing Reveals Hidden Features And Dynamics Of Early Gene Transcription In Paramecium Bursaria Chlorella Virus 1, Guillaume Blanc, Michael Mozar, Irina V. Agarkova, James R. Gurnon, Giane Yanai-Balser, Janet M. Rowe, Yuannan Xia, Jean-Jack Riethoven, David D. Dunigan, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

Paramecium bursaria chlorella virus 1 (PBCV-1) is the prototype of the genus Chlorovirus (family Phycodnaviridae) that infects the unicellular, eukaryotic green alga Chlorella variabilis NC64A. The 331-kb PBCV-1 genome contains 416 major open reading frames. A mRNA-seq approach was used to analyze PBCV-1 transcriptomes at 6 progressive times during the first hour of infection. The alignment of 17 million reads to the PBCV-1 genome allowed the construction of single-base transcriptome maps. Significant transcription was detected for a subset of 50 viral genes as soon as 7 min after infection. By 20 min post infection (p.i.), transcripts were detected for …

Vaccines Within Vaccines: The Use Of Adenovirus Types 4 And 7 As Influenza Vaccine Vectors, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

Adenovirus Types 4 and 7 (Ad4 and Ad7) are associated with acute respiratory distress (ARD). In order to prevent widespread Ad-associated ARD (Ad-ARD) the United States military immunizes new recruits using a safe and effective lyophilized wildtype Ad4 and Ad7 delivered orally in an enteric-coated capsule. We cloned Ad4 and Ad7 and modified them to express either a GFP-Luciferase (GFPLuc) fusion gene or a centralized influenza H1 hemagglutinin (HA1-con). BALB/c mice were injected with GFPLuc expressing viruses intramuscularly (i.m.) and intranasally (i.n.). Ad4 induced significantly higher luciferase expression levels as compared with Ad7 by both routes. Ad7 transduction was restored …

Cluster M Mycobacteriophages Bongo, Pegleg, And Rey With Unusually Large Repertoires Of Trna Isotypes, Welkin H. Pope, Kirk R. Anders, Madison Baird, Charles A. Bowman

University Faculty Publications and Creative Works

Genomic analysis of a large set of phages infecting the common host Mycobacterium smegmatis mc2155 shows that they span considerable genetic diversity. There are more than 20 distinct types that lack nucleotide similarity with each other, and there is considerable diversity within most of the groups. Three newly isolated temperate mycobacteriophages, Bongo, PegLeg, and Rey, constitute a new group (cluster M), with the closely related phages Bongo and PegLeg forming subcluster M1 and the more distantly related Rey forming subcluster M2. The clusterMmycobacteriophages have siphoviral morphologies with unusually long tails, are homoimmune, and have larger than average genomes (80.2 to …

Cluster M Mycobacteriophages Bongo, Pegleg, And Rey With Unusually Large Repertoires Of Trna Isotypes, Welkin H. Pope, Kirk R. Anders, Madison Baird, Charles A. Bowman

University Faculty Publications and Creative Works

Genomic analysis of a large set of phages infecting the common host Mycobacterium smegmatis mc2155 shows that they span considerable genetic diversity. There are more than 20 distinct types that lack nucleotide similarity with each other, and there is considerable diversity within most of the groups. Three newly isolated temperate mycobacteriophages, Bongo, PegLeg, and Rey, constitute a new group (cluster M), with the closely related phages Bongo and PegLeg forming subcluster M1 and the more distantly related Rey forming subcluster M2. The clusterMmycobacteriophages have siphoviral morphologies with unusually long tails, are homoimmune, and have larger than average genomes (80.2 to …