scholarly journals A Novel Broad Host Range Phage Infecting Alteromonas

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 987
Author(s):  
Xuejin Feng ◽  
Wei Yan ◽  
Anan Wang ◽  
Ruijie Ma ◽  
Xiaowei Chen ◽  
...  
Keyword(s):  
Host Range ◽  
Burst Size ◽  
Nucleotide Metabolism ◽  
Lytic Cycle ◽  
Nucleoside Triphosphate ◽  
Broad Host Range ◽  
Ecological Features ◽  
Wide Host Range ◽  
Genes Encoding ◽  
Ecological Importance

Bacteriophages substantially contribute to bacterial mortality in the ocean and play critical roles in global biogeochemical processes. Alteromonas is a ubiquitous bacterial genus in global tropical and temperate waters, which can cross-protect marine cyanobacteria and thus has important ecological benefits. However, little is known about the biological and ecological features of Alteromonas phages (alterophages). Here, we describe a novel alterophage vB_AmeP-R8W (R8W), which belongs to the Autographiviridae family and infects the deep-clade Alteromonas mediterranea. R8W has an equidistant and icosahedral head (65 ± 1 nm in diameter) and a short tail (12 ± 2 nm in length). The genome size of R8W is 48,825 bp, with a G + C content of 40.55%. R8W possesses three putative auxiliary metabolic genes encoding proteins involved in nucleotide metabolism and DNA binding: thymidylate synthase, nucleoside triphosphate pyrophosphohydrolase, and PhoB. R8W has a rapid lytic cycle with a burst size of 88 plaque-forming units/cell. Notably, R8W has a wide host range, such that it can infect 35 Alteromonas strains; it exhibits a strong specificity for strains isolated from deep waters. R8W has two specific receptor binding proteins and a compatible holin–endolysin system, which contribute to its wide host range. The isolation of R8W will contribute to the understanding of alterophage evolution, as well as the phage–host interactions and ecological importance of alterophages.

scholarly journals Comparative genomic analysis of three intestinal species reveals reductions in secreted pathogenesis determinants in bovine-specific and non-pathogenic Cryptosporidium species

2020 ◽  
Vol 6 (6) ◽  
Author(s):  
Zhixiao Xu ◽  
Na Li ◽  
Yaqiong Guo ◽  
Yaoyu Feng ◽  
Lihua Xiao
Keyword(s):  
Host Range ◽  
Gene Families ◽  
Copy Number Variations ◽  
Gene Organization ◽  
Nucleotide Metabolism ◽  
Comparative Genomic ◽  
Secretory Proteins ◽  
Broad Host Range ◽  
Biological Studies ◽  
Genes Encoding

The three common intestinal Cryptosporidium species in cattle differ significantly in host range, pathogenicity and public health significance. While Cryptosporidium parvum is pathogenic in pre-weaned calves and has a broad host range, C. bovis and C. ryanae are largely non-pathogenic and bovine-specific species in post-weaned calves. Thus far, only the genome of C. parvum has been sequenced. To improve our understanding of the genetic determinants of biological differences among Cryptosporidium spcies, we sequenced the genomes of C. bovis and C. ryanae and conducted a comparative genomics analysis. The genome of C. bovis has a gene content and organization more similar to C. ryanae than to other Cryptosporidium species sequenced to date; the level of similarity in amino acid and nucleotide sequences between the two species is 75.2 and 69.4 %, respectively. A total of 3723 and 3711 putative protein-encoding genes were identified in the genomes of C. bovis and C. ryanae, respectively, which are fewer than the 3981 in C. parvum. Metabolism is similar among the three species, although energy production pathways are further reduced in C. bovis and C. ryanae. Compared with C. parvum, C. bovis and C. ryanae have lost 14 genes encoding mucin-type glycoproteins and three for insulinase-like proteases. Other gene gains and losses in the two bovine-specific and non-pathogenic species also involve the secretory pathogenesis determinants (SPDs); they have lost all genes encoding MEDLE, FLGN and SKSR proteins, and two of the three genes for NFDQ proteins, but have more genes encoding secreted WYLE proteins, secreted leucine-rich proteins and GPI-anchored adhesin PGA18. The only major difference between C. bovis and C. ryanae is in nucleotide metabolism. In addition, half of the highly divergent genes between C. bovis and C. ryanae encode secreted or membrane-bound proteins. Therefore, C. bovis and C. ryanae have gene organization and metabolic pathways similar to C. parvum, but have lost some invasion-associated mucin glycoproteins, insulinase-like proteases, MEDLE secretory proteins and other SPDs. The multiple gene families under positive selection, such as helicase-associated domains, AMP-binding domains, protein kinases, mucins, insulinases and TRAPs could contribute to differences in host specificity and pathogenicity between C. parvum and C. bovis. Biological studies should be conducted to assess the contribution of these copy number variations to the narrow host range and reduced pathogenicity of C. bovis and C. ryanae.

Backyard Farms Represent a Source of Wide Host Range Salmonella Phages That Lysed the Most Common Salmonella Serovars

2018 ◽  
Vol 81 (2) ◽  
pp. 272-278 ◽  
Author(s):  
DÁCIL RIVERA ◽  
VIVIANA TOLEDO ◽  
FRANCISCA DI PILLO ◽  
FERNANDO DUEÑAS ◽  
RODOLFO TARDONE ◽  
...  
Keyword(s):  
Host Range ◽  
Salmonella Enteritidis ◽  
Genetic Relatedness ◽  
Production Systems ◽  
Lytic Cycle ◽  
Salmonella Infections ◽  
Wide Host Range ◽  
Wide Range ◽  
Salmonella Serovars ◽  
Phage Isolation

ABSTRACT The genus Salmonella has more than 2,600 serovars, and this trait is important when considering interventions for Salmonella control. Bacteriophages that are used for biocontrol must have an exclusively lytic cycle and the ability to lyse several Salmonella serovars under a wide range of environmental conditions. Salmonella phages were isolated and characterized from 34 backyard production systems (BPSs) with a history of Salmonella infections. BPSs were visited once, and cloacal or fecal samples were processed for phage isolation. Four hosts, Salmonella serovars Enteritidis, Heidelberg, Infantis, and Typhimurium, were used for phage isolation. The host range of the phages was later characterized with a panel of 23 Salmonella serovars (serovar diversity set) and 31 isolates obtained from the same farms (native set). Genetic relatedness for 10 phages with a wide host range was characterized by restriction fragment length polymorphism, and phages clustered based on the host range. We purified 63 phages, and 36 phage isolates were obtained on Salmonella Enteritidis, 16 on Salmonella Heidelberg, and 11 on Salmonella Infantis. Phages were classified in three clusters: (i) phages with a wide host range (cluster I), (ii) phages that lysed the most susceptible Salmonella serovars (serogroup D) and other isolates (cluster II), and (iii) phages that lysed only isolates of serogroup D (cluster III). The most susceptible Salmonella serovars were Enteritidis, Javiana, and Dublin. Seven of 34 farms yielded phages with a wide host range, and these phages had low levels of genetic relatedness. Our study showed an adaptation of the phages in the sampled BPSs to serogroup D Salmonella isolates and indicated that isolation of Salmonella phages with wide host range differs by farm. A better understanding of the factors driving the Salmonella phage host range could be useful when designing risk-based sampling strategies to obtain phages with a wide lytic host range for biocontrol purposes.

scholarly journals Continuous Control of the Flow in Biochemical Pathways through 5′ Untranslated Region Sequence Modifications in mRNA Expressed from the Broad-Host-Range PromoterPm

2011 ◽  
Vol 77 (8) ◽  
pp. 2648-2655 ◽  
Author(s):  
Rahmi Lale ◽  
Laila Berg ◽  
Friederike Stüttgen ◽  
Roman Netzer ◽  
Marit Stafsnes ◽  
...  
Keyword(s):  
Host Range ◽  
Untranslated Region ◽  
Micrococcus Luteus ◽  
Background Level ◽  
Broad Host Range ◽  
Continuous Control ◽  
Wild Type ◽  
Content Type ◽  
Broad Host Range Plasmid ◽  
Genes Encoding

ABSTRACTThe induciblePmpromoter integrated into broad-host-range plasmid RK2 replicons can be fine-tuned continuously between the uninduced and maximally induced levels by varying the inducer concentrations. To lower the uninduced background level while still maintaining the inducibility for applications in, for example, metabolic engineering and synthetic (systems) biology, we report here the use of mutations in thePmDNA region corresponding to the 5′ untranslated region of mRNA (UTR). Five UTR variants obtained by doped oligonucleotide mutagenesis and selection, apparently reducing the efficiency of translation, were all found to display strongly reduced uninduced expression of three different reporter genes (encoding β-lactamase, luciferase, and phosphoglucomutase) inEscherichia coli. The ratio between induced and uninduced expression remained the same or higher compared to cells containing a corresponding plasmid with the wild-type UTR. Interestingly, the UTR variants also displayed similar effects on expression when substituted for the native UTR in another and constitutive promoter,P1(Pantitet), indicating a broad application potential of these UTR variants. Two of the selected variants were used to control the production of the C50carotenoid sarcinaxanthin in an engineered strain ofE. colithat produces the precursor lycopene. Sarcinaxanthin is produced in this particular strain by expressing threeMicrococcus luteusderived genes from the promoterPm. The results indicated that UTR variants can be used to eliminate sarcinaxanthin production under uninduced conditions, whereas cells containing the corresponding plasmid with a wild-type UTR produced ca. 25% of the level observed under induced conditions.

scholarly journals Isolation of Polyvalent Bacteriophages by Sequential Multiple-Host Approaches

2015 ◽  
Vol 82 (3) ◽  
pp. 808-815 ◽  
Author(s):  
Pingfeng Yu ◽  
Jacques Mathieu ◽  
Mengyan Li ◽  
Zhaoyi Dai ◽  
Pedro J. J. Alvarez
Keyword(s):  
Host Range ◽  
Pseudomonas Syringae ◽  
Burst Size ◽  
Broad Host Range ◽  
Ecological Significance ◽  
Content Type ◽  
Narrow Host Range ◽  
Isolation Methods ◽  
Culture Independent ◽  
K 12

ABSTRACTMany studies on phage biology are based on isolation methods that may inadvertently select for narrow-host-range phages. Consequently, broad-host-range phages, whose ecological significance is largely unexplored, are consistently overlooked. To enhance research on such polyvalent phages, we developed two sequential multihost isolation methods and tested both culture-dependent and culture-independent phage libraries for broad infectivity. Lytic phages isolated from activated sludge were capable of interspecies or even interorder infectivity without a significant reduction in the efficiency of plating (0.45 to 1.15). Two polyvalent phages (PX1 of thePodoviridaefamily and PEf1 of theSiphoviridaefamily) were characterized in terms of adsorption rate (3.54 × 10−10to 8.53 × 10−10ml/min), latent time (40 to 55 min), and burst size (45 to 99 PFU/cell), using different hosts. These phages were enriched with a nonpathogenic host (Pseudomonas putidaF1 orEscherichia coliK-12) and subsequently used to infect model problematic bacteria. By using a multiplicity of infection of 10 in bacterial challenge tests, >60% lethality was observed forPseudomonas aeruginosarelative to uninfected controls. The corresponding lethality forPseudomonas syringaewas ∼50%. Overall, this work suggests that polyvalent phages may be readily isolated from the environment by using different sequential hosts, and this approach should facilitate the study of their ecological significance as well as enable novel applications.

scholarly journals SGP-C: A Broad Host Range Temperate Bacteriophage; Against Salmonella gallinarum

2022 ◽  
Vol 12 ◽  
Author(s):  
Syeda Zainab Ilyas ◽  
Hafsa Tariq ◽  
Abdul Basit ◽  
Hamza Tahir ◽  
Zulquernain Haider ◽  
...  
Keyword(s):  
Host Range ◽  
Burst Size ◽  
Gc Content ◽  
Broad Host Range ◽  
Temperate Bacteriophage ◽  
Salmonella Gallinarum ◽  
Double Stranded Dna ◽  
C Genome ◽  
Super Infection ◽  
Lysogenic Phage

Salmonella gallinarum is a poultry restricted-pathogen causing fowl-typhoid disease in adult birds with mortality rates up-to 80% and exhibit resistance against commonly used antibiotics. In this current study, a temperate broad host range bacteriophage SGP-C was isolated against S. gallinarum from poultry digesta. It showed infection ability in all the 15 tested field strains of S. gallinarum. The SGP-C phage produced circular, turbid plaques with alternate rings. Its optimum activity was observed at pH 7.0 and 37–42°C, with a latent period of 45 min and burst size of 187 virions/bacterial cell. The SGP-C lysogens, SGPC-L5 and SGPC-L6 exhibited super-infection immunity against the same phage, an already reported feature of lysogens. A virulence index of 0.5 and 0.001 as MV50 of SGP-C suggests its moderate virulence. The genome of SGP-C found circular double stranded DNA of 42 Kbp with 50.04% GC content, which encodes 63 ORFs. The presence of repressor gene at ORF49, and absence of tRNA sequence in SGP-C genome indicates its lysogenic nature. Furthermore, from NGS analysis of lysogens we propose that SGP-C genome might exist either as an episome, or both as integrated and temporary episome in the host cell and warrants further studies. Phylogenetic analysis revealed its similarity with Salmonella temperate phages belonging to family Siphoviridae. The encoded proteins by SGP-C genome have not showed homology with any known toxin and virulence factor. Although plenty of lytic bacteriophages against this pathogen are already reported, to our knowledge SGP-C is the first lysogenic phage against S. gallinarum reported so far.

scholarly journals Characterization of the Three New Kayviruses and Their Lytic Activity Against Multidrug-Resistant Staphylococcus aureus

2019 ◽  
Vol 7 (10) ◽  
pp. 471 ◽  
Author(s):  
Natalia Łubowska ◽  
Bartłomiej Grygorcewicz ◽  
Katarzyna Kosznik-Kwaśnicka ◽  
Agata Zauszkiewicz-Pawlak ◽  
Alicja Węgrzyn ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Burst Size ◽  
Genomic Analysis ◽  
Multidrug Resistant ◽  
Biological Properties ◽  
Lytic Activity ◽  
Broad Host Range ◽  
Transmission Electron ◽  
Short Latent Period

The development of antimicrobial resistance has become a global concern. One approach to overcome the problem of drug resistance is the application of bacteriophages. This study aimed at characterizing three phages isolated from sewage, which show lytic activity against clinical isolates of multidrug-resistant Staphylococcus aureus. Morphology, genetics and biological properties, including host range, adsorption rate, latent time, phage burst size and lysis profiles, were studied in all three phages. As analyzed by transmission electron microscopy (TEM), phages vB_SauM-A, vB_SauM-C, vB_SauM-D have a myovirion morphology. One of the tested phages, vB_SauM-A, has relatively rapid adsorption (86% in 17.5 min), short latent period (25 min) and extremely large burst size (~500 plaque-forming units (PFU) per infected cell). The genomic analysis revealed that vB_SauM-A, vB_SauM-C, vB_SauM-D possess large genomes (vB_SauM-A 139,031 bp, vB_SauM-C 140,086 bp, vB_SauM-D 139,088 bp) with low G+C content (~30.4%) and are very closely related to the phage K (95–97% similarity). The isolated bacteriophages demonstrate broad host range against MDR S. aureus strains, high lytic activity corresponding to strictly virulent life cycle, suggesting their potential to treat S. aureus infections.

Isolation and properties of a bacteriophage lytic for a wide range of pseudomonads

1971 ◽  
Vol 17 (5) ◽  
pp. 677-682 ◽  
Author(s):  
R. A. Kelln ◽  
R. A. J. Warren
Keyword(s):  
Latent Period ◽  
Pseudomonas Fluorescens ◽  
Host Range ◽  
Burst Size ◽  
Broad Host Range ◽  
Lytic Bacteriophage ◽  
Bacterial Strains ◽  
Short Tail ◽  
Wide Range ◽  
Different Strains

The lytic bacteriophage ø-S1 was isolated from sewage using a strain of Pseudomonas fluorescens as host. It had a hexagonal head 60 nm in diameter and a short tail 30 nm long. ø-S1 had a broad host range, lysing strains from 10 biotypes of Pseudomonads. Although the latent period was fairly constant for the bacterial strains tested, the burst size varied considerably. The rate of adsorption of the phage to different strains also varied considerably.

scholarly journals Causes and consequences of bacteriophage diversification via genetic exchanges across lifestyles and bacterial taxa

2021 ◽  
Author(s):  
Jorge A Moura de Sousa ◽  
Eugen Pfeifer ◽  
Marie Touchon ◽  
Eduardo P C Rocha
Keyword(s):  
Gene Flow ◽  
Host Range ◽  
Dna Packaging ◽  
Nucleotide Metabolism ◽  
Gene Exchange ◽  
End Joining ◽  
Virion Assembly ◽  
Narrow Host Range ◽  
Genes Encoding ◽  
Non Homologous End Joining

Abstract Bacteriophages (phages) evolve rapidly by acquiring genes from other phages leading to mosaic genomes. Here, we identify numerous genetic transfers between distantly related phages and aim at understanding their frequency, consequences and the conditions favoring them. Gene flow tends to occur between phages that are enriched for recombinases, transposases and non-homologous end joining, suggesting that both homologous and illegitimate recombination contribute to gene flow. Phage family and host phyla are strong barriers to gene exchange, but phage lifestyle is not. Even if we observe four times more recent transfers between temperate phages than between other pairs, there is extensive gene flow between temperate and virulent phages, and between the latter. These predominantly involve virulent phages with large genomes previously classed as low gene flux, and lead to the preferential transfer of genes encoding functions involved in cell energetics, nucleotide metabolism, DNA packaging and injection, and virion assembly. Such exchanges may contribute to the observed twice larger genomes of virulent phages. We used genetic transfers, which occur upon co-infection of a host, to compare phage host range. We found that virulent phages have broader host ranges and can mediate genetic exchanges between narrow host range temperate phages infecting distant bacterial hosts, thus contributing to gene flow between virulent phages, as well as between temperate phages. This gene flow drastically expands the gene repertoires available for phage and bacterial evolution, including the transfer of functional innovations across taxa.

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