THE HOST RANGE AND PLAQUE MORPHOLOGY OF RABBITPOX VIRUS (RPU+) AND ITS U MUTANTS ON CHICK FIBROBLAST, PK-2A, AND L929 CELLS.
Explore the source record for details and available documents.
Animals↗
SEARCH · Search PubMed
Results for “host range”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Molecular analysis and characterization of a broad-host-range plasmid, pEP2.
Plasmid pEP2 was found to encode a protein, RepA, which is essential and rate limiting for its replication in Escherichia coli and Corynebacterium pseudotuberculosis. Mutations which altered the rate of synthesis of this protein in E. coli affected the copy number and segregational stability of pEP2 in the two hosts. RepA contains 483 amino acid residues and has the calculated molecular weight of 53,925. It shows 45% amino acid residue identity with open reading frame ORF2 of pSR1, a plasmid isolated from Corynebacterium glutamicum (J. A. C. Archer and A. J. Sinskey, J. Gen. Microbiol. 139:1753-1759, 1993). Plasmid pEP2 was shown to accumulate single-stranded DNA corresponding to the RepA coding strand during its replication in E. coli and C. pseudotuberculosis, suggesting that it may replicate by a rolling circle mechanism. However, RepA has no significant sequence homology with the replication initiator proteins of plasmids known to use this mode of replication.
Amino Acid Sequence↗
Experimental host range studies with Heleidomermis magnapapula (Mermithidae), a parasite of Culicoides variipennis (Ceratopogonidae).
Infectivity of the mermithid nematode Heleidomermis magnapapula, a parasite of Culicoides variipennis variipennis and C. v. sonorensis in dairy wastewater pond habitats, was tested against larvae of aquatic Diptera in the laboratory. Observations were made on preparasite penetration. If the host species could be reared after parasitization, further observations determined nematode development and emergence. Genera in the families Syrphidae (Eristalis), Psychodidae (Psychoda), and Chironomidae (Tanypus), common in wastewater pond habitats, were not attacked. Larvae of Bezzia and Dasyhelea (Ceratopogonidae) also were not attacked. Larvae of Chironomus (Chironomidae) were penetrated, but rapidly encapsulated the nematodes. All Culicoides spp. exposed were readily penetrated by H. magnapapula preparasites. The nematodes successfully emerged from C. v. occidentalis. Some nematode maturation was seen in C. lahontan, and limited adult nematode emergence was seen in C. boydi and C. cacticola. No nematode development was observed in 5 other Culicoides spp. penetrated.
Animals↗
Host range susceptibility of Enterococcus sp. strains isolated from diseased turbot: possible routes of infection.
Experiments were conducted to assess the pathogenicity of Enterococcus sp. strains isolated from diseased turbot for several fish species (turbot, salmon, trout, and seabream), as well as for mice. The intraperitoneal injection assays indicated that the tested strains showed host specificity for turbot, with a high degree of virulence (50% lethal dose of 10(4) cells per g of fish). The Spanish Enterococcus sp. isolates were nonpathogenic for the other fish species studied and for mice. The possible routes of infection were determined by bath exposure (with and without prior abrasion of the skin) and by intragastric inoculations with food and feces contaminated with the pathogen. The bath challenges indicated that the Enterococcus isolates were able to overcome the defense mechanisms present on the surface of the turbot only if the skin was abraded prior to the exposure. The antibacterial activities of components of a glycoprotein nature present in the turbot skin mucus are probably responsible in part for the resistance in noninjured fish to infection. On the other hand, we demonstrated the capacity of this pathogen to overcome adverse conditions in the stomachs of fish when associated with food or fecal material, since it is able to establish an infective state and to produce mortalities after 16 to 20 days postingestion. From all of these findings, we can conclude that horizontal transmissions through water and the fecal-oral route are the main avenues of infection of turbot streptococcosis.
Animals↗
Genetic identification and host range of the Spanish strains of Echinococcus granulosus.
Three strains of Echinococcus granulosus have been previously identified in Spain (namely 'sheep', 'horse' and 'pig'), but these Spanish strains have not been properly genotyped yet. The aim of the present research was to identify the genotype to which they correspond to. Cyst isolates were obtained from different host species, and the strain to which each belonged was established by analysis of its random amplified polymorphic DNA (RAPD) banding patterns. These results were compared to those obtained with the analysis of two mitochondrial fragment sequences (cytochrome oxidase 1 (CO1) and NADH dehydrogenase 1 (ND1)) from each isolate. The Spanish 'sheep' strain corresponded with the genotype 1 (G1) of the parasite, infecting Spanish sheep, cattle, goat, pig, wild boar and human; the Spanish 'horse' strain corresponded with the genotype 4 (G4), only infecting Spanish horses; and the Spanish 'pig' strain corresponded with the genotype 7 (G7), infecting Spanish goat, pig and wild boar. Goat, pig and wild boar can be infected by two genotypes, G1 and G7. This circumstance, and especially the possibility of sylvatic intermediate hosts serving as reservoirs of the G1 genotype of the parasite, must be taken into consideration by authorities in order to develop and evaluate effective anti-hydatidosis programmes.
Alcohol Oxidoreductases↗
Localization of an origin of replication in Corynebacterium diphtheriae broad host range plasmid pNG2 that also functions in Escherichia coli.
Subcloning and protoplast transformation studies identified a 2.6 kb fragment of Corynebacterium diphtheriae plasmid pNG2 which contains an origin of replication (oriR). Molecular combination of the 2.6 kb oriR cartridge with Escherichia coli plasmid pUC18CmR enabled the E. coli cloning vector to replicate within several species of Corynebacterium host cells. A 2.6 kb plasmid formed from the oriR cartridge alone is capable of replicating in E. coli. This suggests that a single origin could be used in vectors shuttling between Corynebacterium spp. and E. coli.
Cloning, Molecular↗
Characterization of a wide host range plasmid pANV-6 from Citrobacter diversus.
pANV-6 is a 5.85 kb, streptomycin resistant, high copy number plasmid isolated from a multi drug resistant clinical isolate of C. diversus by transformation in Escherichia coli C-600. The plasmid was very stable, noncurable and could not be amplified with chloramphenicol. It was non-conjugative among Enterobacteriaceae hosts. Plasmid was transferred by transformation to several Gram negative and Gram positive hosts. These included Esch. coli, Serratia marcescens, Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, Corynebacterium glutamicum. From Staph. aureus it was transferred by conjugation to other Staph. aureus, Staph. epidermidis and Bacillus subtilis. Plasmid was incompatible with standard plasmids belonging to incompatibility groups H1, H2 = S,J,P and T of coliform bacteria. Plasmid has one site for restriction enzyme EcoRI and Pst I, three for Bgl 1 and non for Bgl 1, Bam HI, Hind III and X ba I.
Citrobacter↗
Stability of r-microbes: stabilization of plasmid vectors by the partitioning function of broad-host-range plasmid RP4.
The genes for biosynthesis of the biodegradable polymer poly-beta-hydroxybutyric acid (PHB) cloned from Alcaligenes eutrophus H16 were used for synthesis of PHB with recombinant Escherichia coli strains. It was recognized that the PHB-biosynthesis genes cause segregational instability to the plasmids used as vectors. Recombinant PHB-plasmids are rapidly lost from host cells and plasmid-free cells occur at high rates, even under conditions of selection for the plasmids. Cloning the partitioning region of plasmid RP4 onto such plasmids resulted in a high degree of stabilization. These par-stabilized recombinant PHB-plasmids could be maintained quite efficiently in batch cultivation experiments in the absence of any selection pressure.
Alcaligenes↗
Replication of the broad host range plasmid RSF1010: requirement for three plasmid-encoded proteins.
Cloning of specific regions of plasmid RSF1010, in conjunction with in vitro replication studies, has revealed three novel genes: repA, repB, and repC. They are clustered in one region of the plasmid, separated from the origin of replication by regions that are not essential for plasmid viability in an Escherichia coli host. In vivo, a 2.1-kilobase segment of the plasmid, bearing the replication origin, can establish itself as an autonomous replicon if the DNA region carrying the three rep genes is present in the same cell on an independent plasmid. In vitro, RSF1010 DNA is efficiently replicated by an ammonium sulfate fraction from the E. coli extract, provided the extracts are prepared from cells that can supply the required rep gene products. Using cells containing the cloned rep gene region as a source of elevated levels of the rep proteins, we have partially purified these proteins in functional form. When added to an enzyme fraction derived from plasmid-free cells, they specifically promote the replication of plasmid DNA bearing the RSF1010 origin.
Bacterial Proteins↗
Expression of incompatibility by derivatives of the broad host-range inc P-1 plasmid RK2.
A segment of DNA encoding incompatibility on the inc P-1 plasmid pRK248 was identified by the analysis of deletions generated in vitro, and then cloned into several unrelated and mutually compatible plasmids. These derivatives were tested for expression of P-1 incompatibility. It was demonstrated by transformation experiments that P-1 plasmids were efficiently eliminated from an E. coli host following introduction of any one of the derivatives. However, all the derivatives were compatible with each other. The cloned segment of pRK248 DNA is itself capable of autonomous replication, without being cloned into any plasmid, if plasmid-specified gene products are provided in trans. This satellite plasmid is eliminated from the cell by the inc P-1 plasmid pRK286. The results argue against a partitioning mechanism as the basis for P-1 incompatibility but are consistent with incompatibility being the consequence of negative regulation of copy number. For the inc P-1 system, susceptibility of the plasmid to elimination, but not its ability to eliminate, requires that the P-1 replication system is active.
Chromosome Mapping↗
Host range restriction of vaccinia virus in Chinese hamster ovary cells: relationship to shutoff of protein synthesis.
Chinese hamster ovary cells were found to be nonpermissive for vaccinia virus. Although early virus-induced events occurred in these cells (RNA and polypeptide synthesis), subsequent events appeared to be prevented by a very rapid and nonselective shutoff of protein synthesis. Within less than 2 h after infection, both host and viral protein syntheses were arrested. At low multiplicities of infection, inhibition of RNA synthesis with cordycepin resulted in failure of the virus to block protein synthesis. Moreover, infection of the cells in the presence of cycloheximide prevented the immediate onset of shutoff after reversal of cycloheximide. Inactivation of virus particles by UV irradiation also impaired the capacity of the virus to inhibit protein synthesis. These results suggested that an early vaccinia virus-coded product was implicated in the shutoff of protein synthesis. Either the nonpermissive Chinese hamster ovary cells were more sensitive to this inhibition than permissive cells, or a regulatory control of the vaccinia shutoff function was defective.
Cell Line↗
DNA packaging and developmental intermediates of a broad host range Vibrio vulnificus bacteriophage 71A-6.
The structural intermediates in the capsid assembly and DNA packaging pathway of Vibrio vulnificus bacteriophage 71A-6, a rod-shaped double-stranded DNA podovirus, were isolated by ultracentrifugation and studied by electron microscopy, SDS-PAGE and pulsed-field gel electrophoretic analysis. Bacteriophage 71A-6 synthesized rod-shaped capsids (mean length=200+/-8 nm; mean width=47+/-3 nm n=50) during its development. Several host proteins that probably help in the assembly and maturation of the capsids were attached to these capsids as spherical structures. A capsid-DNA or DNA packaging complex that consisted of the mature capsids, DNA and a 42.5-kDa protein was also isolated. The size of the capsids increased in length and decreased in width (mean length=220+/-8 nm; mean width=45+/-3 nm n=50) either during or after the DNA packaging. The capsid fractions contained about 12 phage structural proteins and eight host proteins. At least three proteins were tentatively identified: a 38.5-kDa major capsid protein, a 35.2-kDa tail protein and 42.5-kDa packaging initiator or terminator protein. The size of the bacteriophage 71A-6 genome was determined to be 143.0-kb by pulsed-field gel electrophoresis. The total mass of all the mature phage proteins corresponded to only 14.0% of the coding capacity of phage genome.
Bacteriophages↗
Antennal sensilla of two female anopheline sibling species with differing host ranges.
BACKGROUND: Volatile odors are important sensory inputs that shape the behaviour of insects, including agricultural pests and disease vectors. Anopheles gambiae s.s. is a highly anthropophilic mosquito and is the major vector for human malaria in sub-Sahara Africa, while Anopheles quadriannulatus, largely due to its zoophilic behaviour, is considered a non-vector species in the same region. Careful studies of olfaction in these sibling species may lead to insights about the mechanisms that drive host preference behaviour. In the present study, the external anatomy of the antenna, the principle olfactory organ in the female mosquito of both species, was examined as an initial step toward more detailed comparisons. METHODS: Scanning electron and light microscopy were used to examine the antennae ultrastructures of adult female An. gambiae s.s. and An. quadriannulatus. Sensory structures, called sensilla, were categorized and counted; their distributions are reported here as well as densities calculated for each species. RESULTS: Both An. gambiae s.s. and An. quadriannulatus bear five classes of sensilla on their antennae: chaetica (bristles), trichodea (hairs), basiconica (pegs), coeloconica (pitted pegs), and ampullacea (pegs in tubes). Female An. quadriannulatus antennae have approximately one-third more sensilla, and a proportionally larger surface area, than female An. gambiae s.s. antennae. CONCLUSION: The same types of sensilla are found on the antennae of both species. While An. quadriannulatus has greater numbers of each sensilla type, sensilla densities are very similar for each species, suggesting that other factors may be more important to such olfactory-driven behaviours as host preference.
Animals↗
Host range tests with Edhazardia aedis (Microsporida: Culicosporidae) against northern Nearctic mosquitoes.
Twelve species of northern Nearctic mosquitoes representing five genera (Aedes, Anopheles, Culex, Culiseta, and Psorphora) were bioassayed for susceptibility to Edhazardia aedis, an exotic, heterosporous, microsporidian parasite of the yellow fever mosquito, Aedes aegypti. Infections were achieved in Aedes atropalpus, Aedes triseriatus, and Aedes vexans following oral ingestion of uninucleate spores obtained from patently infected Ae. aegypti larvae. The microsporidium underwent normal vegetative growth and development in each unnatural mosquito host; the only differences observed were in the degree of infection. With the exception of adult oenocytes, the predominant sites of infection in Ae. triseriatus were generally similar to those in Ae. aegypti. These included the gastric caeca and muscle tissue in larvae and fat body tissue in adult females. Binucleate spores, which are normally responsible for ovarian infection and transovarial transmission in Ae. aegypti, were produced in all but one (Ae. atropalpus) susceptible host. However, E. aedis was not transmitted transovarially to larvae of the filial generation by these alternate female hosts thus indicating a high level of specificity for Ae. aegypti. Since E. aedis can not complete its normal life cycle through two successive host generations in alternate host mosquitoes, its potential as a biological control agent would appear to be limited to Ae. aegypti.
Aedes↗
Adenovirus type 40 and 41 growth in vitro: host range diversity reflected by differences in patterns of DNA replication.
Subgroup F adenoviruses adapt poorly to cell culture, but the reasons for their fastidious nature are as yet ill defined. In an attempt to gain an overview of the differences in replication between adenovirus type 2 (Ad2) and representative strains of Ad40 and Ad41, cell lines which show different degrees of permissiveness to Ad40 and Ad41 were infected and examined with respect to three key functions in the Ad2 life cycle: host protein shutoff, DNA synthesis, and late antigen synthesis. The complexity of growth patterns exhibited by the subgroup F adenoviruses suggests that defectiveness is a multifactorial phenomenon not easily explainable by a single aberrant function. Furthermore, results suggest that there may be replicative defects in subgroup F adenoviruses which are not shared by both serotypes or by all strains.
Adenoviruses, Human↗
HIV-1 infectivity and host range modification by cathepsin D present in human vaginal secretions.
OBJECTIVE: To investigate HIV-1 infectivity in the natural environment of vaginal secretions. DESIGN: Vaginal wash samples collected from 14 healthy women were incubated in vitro with various HIV-1 strains for 10 min at 37 degrees C and then assayed for infectivity on primary lymphocyte cultures, or on CEM cells, or on CD4- ME180 cells derived from vaginal epithelium. METHODS: HIV-1 infectivity was measured by early virus growth in the various host cells tested using a quantitative p24 assay and by the Karber procedure. RESULTS: Preincubation of HIV-1(IIIB) with vaginal wash samples or 2 microg/ml cathepsin D increased the ability of the virus to grow in lymphocyte cultures. The vaginal wash effect was abolished by 5 microg/ml pepstatin A, an inhibitor of aspartyl proteases. Presence of precursor and mature forms of cathepsin D in vaginal wash was demonstrated after passage through a pepstatin A-agarose column. Median tissue culture infective doses of HIV-1(IIIB) and HIV-1(JRFL) strains were increased 14.4-fold and 18-fold, respectively, after preincubation in vaginal wash sample, and were increased by pretreatment with 2 microg/ml cathepsin D. When CD4 receptors of CEMss cells were blocked by OKT4a monoclonal antibody, the cells lost susceptibility to HIV-1 (IIIB), but supported the growth of virus pretreated with vaginal wash sample or cathepsin D. These treated viruses were able to initiate infection of CD4-ME180 epithelial cells, which were not receptive to untreated virus. ME180 cells were shown to possess the messenger of CXC-chemokine receptor-4. CONCLUSIONS: Vaginal secretions may help HIV-1 transmission to women by increasing infectivity for CD4+ cells and allowing entrance into some CD4-epithelial cells.
CD4-Positive T-Lymphocytes↗
Effector loss and gain drives host range at a fitness cost.
Epidemic preparedness depends on tracking microbial evolution that drives shifts in ecological behaviors such as disease emergence. However, the genetic constraints mediating microbial emergence for generalist and specialist behaviors remain poorly described. Here, we addressed this question by combining comparative and functional genomics with phylogeny-based evolutionary analyses of the cereal pathogen Xanthomonas translucens. We show that a generalist X. translucens subgroup arose from a specialist ancestor, and the loss of a single effector gene, xopAL1, contributed to the generalist host expansion by promoting host jump from barley to wheat. Deleting barley-specialist X. translucens xopAL1 recapitulated the host jump to wheat and demonstrates risk across each globally distributed genetic lineage. However, this niche expansion via XopAL1 loss incurs a significant fitness cost to colonize barley. Moreover, the specialist lineage gained an additional effector gene, xopAJ, which enhanced virulence on barley while restricting oat infection, thereby reinforcing niche specialization. We further conducted transcriptomic analysis of wheat and determined that XopAL1 triggers a defense response that involves the reduction of photosynthetic processes. Our work provides an experimentally validated evolutionary framework to understand mechanisms of intergenera host jump. Overall, we demonstrate that single events of gene loss and gain shape ecological behaviors by creating a dynamic trade-off between niche breadth and specialization.
Triticum↗
Extended Host Range of Agrobacterium tumefaciens in the Genus Pinus.
Two-to 4-month-old seedlings of nine pine species (Pinus eldarica Medw., Pinus elliottii Engelm., Pinus jeffreyi Grev. & Balf., Pinus lambertiana Dougl., Pinus ponderosa Laws., Pinus radiata D. Don, Pinus sylvestris L., Pinus taeda L., Pinus virginiana Mill), Douglas fir (Pseudotsuaa menziesii (Mirb.) Franco) and incense cedar (Libocedrus decurrens Torr.) were inoculated with five strains of Agrobacterium tumefaciens. Transformation occurred in all conifer species tested as determined by gall formation and opine production. The frequency of gall formation varied by host species, by bacterial strain, and was related to the age of the stem when inoculated. Galls were visible 8 to 12 weeks after inoculation and were small (often less than 2.5 millimeters in diameter). Fewer than half (230 of 502) of the galls originally formed on the trees were present after 1 year, and 26 of these grew to diameters greater than 2 centimeters. The majority of these larger galls (18 of 26) were found in P. radiata. Bacterial strain-specific opines were found in 67 of the 81 gall tissues sampled.
Journal Article↗