Novel narrow-host-range vectors for direct cloning of foreign DNA inPseudomonas

Bacteriophages are viruses that specifically infect target bacteria. Recently, bacteriophages have been considered potential biological control agents for bacterial pathogens due to their host specificity. Pseudomonas syringae pv. actinidiae (Psa) is a reemerging pathogen that causes bacterial canker of kiwifruit (Actinidia sp.). The economic impact of this pest and the development of resistance to antibiotics and copper sprays in Psa and other pathovars have led to investigation of alternative management strategies. Phage therapy may be a useful alternative to conventional treatments for controlling Psa infections. Although the efficacy of bacteriophage φ6 was evaluated for the control of Psa, the characteristics of other DNA bacteriophages infecting Psa remain unclear. In this study, the PHB09 lytic bacteriophage specific to Psa was isolated from kiwifruit orchard soil. Extensive host range testing using Psa isolated from kiwifruit orchards and other Pseudomonas strains showed PHB09 has a narrow host range. It remained stable over a wide range of temperatures (4–50 °C) and pH values (pH 3–11) and maintained stability for 50 min under ultraviolet irradiation. Complete genome sequence analysis indicated PHB09 might belong to a new myovirus genus in Caudoviricetes. Its genome contains a total of 94,844 bp and 186 predicted genes associated with phage structure, packaging, host lysis, DNA manipulation, transcription, and additional functions. The isolation and identification of PHB09 enrich the research on Pseudomonas phages and provide a promising biocontrol agent against kiwifruit bacterial canker.

Download Full-text

Emergence and Dissemination of Enterobacteriaceae Isolates Producing CTX-M-1-Like Enzymes in Spain Are Associated with IncFII (CTX-M-15) and Broad-Host-Range (CTX-M-1, -3, and -32) Plasmids

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01070-06 ◽

2006 ◽

Vol 51 (2) ◽

pp. 796-799 ◽

Cited By ~ 82

Author(s):

Ângela Novais ◽

Rafael Cantón ◽

Raquel Moreira ◽

Luísa Peixe ◽

Fernando Baquero ◽

...

Keyword(s):

Host Range ◽

Broad Host Range ◽

Narrow Host Range

ABSTRACT The spread of CTX-M-1-like enzymes in Spain is associated with particular plasmids of broad-host-range IncN (bla CTX-M-32, bla CTX-M-1), IncL/M (bla CTX-M-1), and IncA/C2 (bla CTX-M-3) or narrow-host-range IncFII (bla CTX-M-15). The identical genetic surroundings of bla CTX-M-32 and bla CTX-M-1 and their locations on related 40-kb IncN plasmids indicate the in vivo evolution of this element.

Download Full-text

A revision of species of the genus Haematoloechus Looss, 1899 (Trematoda: Haematoloechidae) from Canada and the United States

Canadian Journal of Zoology ◽

10.1139/z81-252 ◽

1981 ◽

Vol 59 (9) ◽

pp. 1836-1846 ◽

Cited By ~ 16

Author(s):

Murray J. Kennedy

Keyword(s):

United States ◽

Host Range ◽

Geographical Variation ◽

Rana Catesbeiana ◽

Field Studies ◽

The United States ◽

Valid Species ◽

Narrow Host Range ◽

Species Groups ◽

Degree Of Maturity

Previous experimental and field studies have shown that variations within the genus Haematoloechus may result from differences in age and degree of maturity, extent of crowding, species of host, and other factors.Based on these observations, only 6 of the 15 previously known species from Canada and the United States are considered valid. The valid species and their synonyms are as follows: Haematoloechus longiplexus Stafford, 1902; H. breviplexus Stafford, 1902; H. varioplexus Stafford, 1902 (= H. parviplexus, = H. buttensis, = H. similiplexus, = H. floedae, and H. uniplexus); H. kernensis Ingles, 1932 (= H. tumidus); H. medioplexus Stafford, 1902; and H. complexus (Seely, 1906) (= H. coloradensis, = H. confusus, = H. oxyorchis).The existence of three species groups is hypothesized. Haematoloechus longiplexus and H. breviplexus constitute one group, characterized by little geographical variation and a narrow host range. They are typically parasites of Rana catesbeiana and R. clamitans. Haematoloechus varioplexus and H. kernensis constitute the second group. These species have a wider host range and greater variation in characters purported to be specific differences. The third group includes those lung flukes which do not contain extracaecal loops (H. medioplexus and H. complexus). Of these, only H. medioplexus had little geographical variation and was found to occur in a single frog host.

Download Full-text

Mice Expressing Minimally Humanized CD81 and Occludin Genes Support Hepatitis C Virus Uptake In Vivo

Journal of Virology ◽

10.1128/jvi.01799-16 ◽

2016 ◽

Vol 91 (4) ◽

Cited By ~ 13

Author(s):

Qiang Ding ◽

Markus von Schaewen ◽

Gabriela Hrebikova ◽

Brigitte Heller ◽

Lisa Sandmann ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Host Range ◽

Amino Acid Sequences ◽

Host Factors ◽

Narrow Host Range ◽

Junction Protein ◽

Mouse Hepatocytes

ABSTRACT Hepatitis C virus (HCV) causes chronic infections in at least 150 million individuals worldwide. HCV has a narrow host range and robustly infects only humans and chimpanzees. The underlying mechanisms for this narrow host range are incompletely understood. At the level of entry, differences in the amino acid sequences between the human and mouse orthologues of two essential host factors, the tetraspanin CD81 and the tight junction protein occludin (OCLN), explain, at least in part, HCV's limited ability to enter mouse hepatocytes. We have previously shown that adenoviral or transgenic overexpression of human CD81 and OCLN facilitates HCV uptake into mouse hepatocytes in vitro and in vivo. In efforts to refine these models, we constructed knock-in mice in which the second extracellular loops of CD81 and OCLN were replaced with the respective human sequences, which contain the determinants that are critical for HCV uptake. We demonstrate that the humanized CD81 and OCLN were expressed at physiological levels in a tissue-appropriate fashion. Mice bearing the humanized alleles formed normal tight junctions and did not exhibit any immunologic abnormalities, indicating that interactions with their physiological ligands were intact. HCV entry factor knock-in mice take up HCV with an efficiency similar to that in mice expressing HCV entry factors transgenically or adenovirally, demonstrating the utility of this model for studying HCV infection in vivo. IMPORTANCE At least 150 million individuals are chronically infected with hepatitis C virus (HCV). Chronic hepatitis C can result in progressive liver disease and liver cancer. New antiviral treatments can cure HCV in the majority of patients, but a vaccine remains elusive. To gain a better understanding of the processes culminating in liver failure and cancer and to prioritize vaccine candidates more efficiently, small-animal models are needed. Here, we describe the characterization of a new mouse model in which the parts of two host factors that are essential for HCV uptake, CD81 and occludin (OCLN), which differ between mice and humans, were humanized. We demonstrate that such minimally humanized mice develop normally, express the modified genes at physiological levels, and support HCV uptake. This model is of considerable utility for studying viral entry in the three-dimensional context of the liver and to test approaches aimed at preventing HCV entry.

Download Full-text

Morphological and pathogenic variations in the isolates of Rhizoctonia solani in Bangladesh

Bangladesh Journal of Agricultural Research ◽

10.3329/bjar.v35i3.6443 ◽

1970 ◽

Vol 35 (3) ◽

pp. 375-380 ◽

Cited By ~ 1

Author(s):

BK Goswami ◽

KA Bhuiyan ◽

IH Mian

Keyword(s):

Rhizoctonia Solani ◽

Host Range ◽

Infected Plant ◽

Agar Plate ◽

Narrow Host Range ◽

Ecological Zones ◽

Plant Parts ◽

Virulent Isolate ◽

Wide Host Range ◽

Avirulent Isolate

Rhizoctonia solani isolates were collected from soil of different agro-ecological zones of Bangladesh and also from infected plant parts of different crops and grasses. Collected isolates were classified into five different cluster groups on the basis of morphological and cultural characters. Five isolates taking one from each of the five different cluster groups were selected to study their pathogenicity and host range on 35 different crops. Pathogenicity and host range of the isolates were determined by planting the seeds in water agar plate infested with R. solani isolates and incubated at 25°C temperatures. After analyzing the morphological and cultural characters of the isolates, it was found that there was no relations between the isolates with respect to their origin from where they were collected. It indicated that the diversity among the isolates was not correlated with their origin. In case of host range and pathogenicity among the five selected isolates of different cluster groups, the isolate JES-16 was an avirulent isolate. The isolate SYL-30 had narrow host range and a low virulent isolate. The isolates DIN-8 and GAZ-18 possessed wide host range and might be considered as virulent isolates. The isolate GAZ-9 was a highly virulent isolate with a wide host range. Keywords: Rhizoctonia solani; morphological and pathogenic variations; isolates. DOI: 10.3329/bjar.v35i3.6443Bangladesh J. Agril. Res. 35(3) : 375-380

Download Full-text

Review of species of Entedon Dalman having a complete frontal fork with redefinition of the species-group of cioni Thomson (Hymenoptera: Eulophidae)

Insect Systematics & Evolution ◽

10.1163/187631291x00093 ◽

1991 ◽

Vol 22 (2) ◽

pp. 219-229 ◽

Cited By ~ 3

Author(s):

R.R. Askew

Keyword(s):

New Species ◽

Host Range ◽

Species Group ◽

Check List ◽

Narrow Host Range ◽

Isolated Species

AbstractSpecies of Entedon having a frontal fork with impressed arms extending to the eyes are reviewed and a key is given. Most but not all species having this character belong to the species-group of Entedon cioni which is redefined to exclude apparently unrelated forms. The reliability of certain specific characters is assessed, and in an account of the biology of Entedon it is proposed that their koinobiotic development is conducive to a narrow host range. Taxonomic, biological and distributional data are given in a check-list to Palaearctic and Nearctic species assigned to the species-group of E. cioni. Four new species of Entedon are described: E. incultus sp. n. and E. setifrons sp. n. from Britain and E. oxys sp. n. from Spain belong to the cioni species-group; E. albiscapus sp. n. from France is an isolated species.

Download Full-text

A genetically novel, narrow-host-range isolate of cucumber mosaic virus (CMV) from rosemary

Archives of Virology ◽

10.1007/s00705-016-2874-z ◽

2016 ◽

Vol 161 (7) ◽

pp. 2013-2017 ◽

Cited By ~ 8

Author(s):

Mark Tepfer ◽

Gregory Girardot ◽

Lucie Fénéant ◽

Hana Ben Tamarzizt ◽

Eric Verdin ◽

...

Keyword(s):

Host Range ◽

Cucumber Mosaic Virus ◽

Mosaic Virus ◽

Narrow Host Range

Download Full-text

Identification of Bacteriophages for Biocontrol of the Kiwifruit Canker Phytopathogen Pseudomonas syringae pv. actinidiae

Applied and Environmental Microbiology ◽

10.1128/aem.00062-14 ◽

2014 ◽

Vol 80 (7) ◽

pp. 2216-2228 ◽

Cited By ~ 44

Author(s):

Rebekah A. Frampton ◽

Corinda Taylor ◽

Angela V. Holguín Moreno ◽

Sandra B. Visnovsky ◽

Nicola K. Petty ◽

...

Keyword(s):

Host Range ◽

Pseudomonas Syringae ◽

Management Strategies ◽

Pulse Field ◽

Resistant Bacteria ◽

Bacterial Canker ◽

Content Type ◽

Narrow Host Range ◽

Pulse Field Gel Electrophoresis ◽

Isolation And Characterization

ABSTRACTPseudomonas syringaepv. actinidiae is a reemerging pathogen which causes bacterial canker of kiwifruit (Actinidiasp.). Since 2008, a global outbreak ofP. syringaepv. actinidiae has occurred, and in 2010 this pathogen was detected in New Zealand. The economic impact and the development of resistance inP. syringaepv. actinidiae and other pathovars against antibiotics and copper sprays have led to a search for alternative management strategies. We isolated 275 phages, 258 of which were active againstP. syringaepv. actinidiae. Extensive host range testing onP. syringaepv. actinidiae, other pseudomonads, and bacteria isolated from kiwifruit orchards showed that most phages have a narrow host range. Twenty-four were analyzed by electron microscopy, pulse-field gel electrophoresis, and restriction digestion. Their suitability for biocontrol was tested by assessing stability and the absence of lysogeny and transduction. A detailed host range was performed, phage-resistant bacteria were isolated, and resistance to other phages was examined. The phages belonged to theCaudoviralesand were analyzed based on morphology and genome size, which showed them to be representatives ofMyoviridae,Podoviridae, andSiphoviridae. Twenty-oneMyoviridaemembers have similar morphologies and genome sizes yet differ in restriction patterns, host range, and resistance, indicating a closely related group. Nine of theseMyoviridaemembers were sequenced, and each was unique. The most closely related sequenced phages were a group infectingPseudomonas aeruginosaand characterized by phages JG004 and PAK_P1. In summary, this study reports the isolation and characterization ofP. syringaepv. actinidiae phages and provides a framework for the intelligent formulation of phage biocontrol agents against kiwifruit bacterial canker.

Download Full-text

Puccinia subnitens: An Obscure Rust Pathogen Little-Known for More than a Century

Plant Health Progress ◽

10.1094/php-rv-13-0124 ◽

2014 ◽

Vol 15 (3) ◽

pp. 105-111

Author(s):

Robert M. Harveson

Keyword(s):

Life Cycle ◽

Sugar Beet ◽

Host Range ◽

Host Species ◽

Complex Life Cycle ◽

Narrow Host Range ◽

Rust Diseases ◽

Rust Pathogen

Sugar beet seedling rust, caused by Puccinia subnitens, is a rarely occurring but essentially harmless disease in sugar beet production. However, it has caused substantial but sporadic losses to commercial spinach growers. It has the typically complex life cycle of a macrocyclic rust pathogen, but is also unusual because it is one of the few documented heteroecious rust diseases where the early spore stages (pycnial and aecial) occur on the economic host while the normally damaging, repeating, uredial stage is found on the feral, noneconomic host. Most significantly, it was one of the first heteroecious rust diseases recognized to have the ability to infect numerous, distinct host species with the aecial stage while maintaining a relatively narrow host range for its uredial and telial stages. Accepted 6 June 2014. Published 25 July 2014.

Download Full-text