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21.
Pseudomonas avellanae (Pav) has been reported as the causal agent of bacterial decline and bacterial canker of hazelnut in Italy and Greece, respectively. Both hazelnut diseases were reported to be similar in terms of symptoms, severity and persistence. In this study, we found that both symptomatic and asymptomatic trees in the field were colonized by Pav. Multilocus Sequence Typing (MLST) analysis showed that Pav strains isolated during this study in Italy belong to the P. syringae phylogroup 1 and they are closely related to Pav strains previously isolated in Greece from hazelnut bacterial canker. On the other hand, strains isolated in earlier studies from hazelnut decline in Italy belong to both phylogroup 1 and 2 of P. syringae. Both phylogroup 1 strains of P. syringae from Greece and Italy are different than strains isolated in this study in terms of their capacity to excrete fluorescent pigments on different media. Despite the same plant genotype and cropping practices adopted, the incidence of hazelnut decline ranged from nearly 0 to 91% across our study sites. No disease developed on plants inoculated with Pav through wounding while leaf scar inoculations produced only mild disease symptoms. Based on our results and the previously reported correlation between pedo-climatic conditions and hazelnut decline, we conclude that hazelnut decline in central Italy could be incited by a combination of predisposing (adverse pedo-climatic conditions) and contributing factors (Pav). Because this is a true decline different from “bacterial canker” described in Greece, we refer to it as hazelnut decline (HD). 相似文献
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Rosalba Lepore Andriy Kryshtafovych Markus Alahuhta Harshul A. Veraszto Yannick J. Bomble Joshua C. Bufton Alex N. Bullock Cody Caba Hongnan Cao Owen R. Davies Ambroise Desfosses Matthew Dunne Krzysztof Fidelis Celia W. Goulding Manickam Gurusaran Irina Gutsche Christopher J. Harding Marcus D. Hartmann Christopher S. Hayes Andrzej Joachimiak Petr G. Leiman Peter Loppnau Andrew L. Lovering Vladimir V. Lunin Karolina Michalska Ignacio Mir-Sanchis AK Mitra John Moult George N. Phillips Jr Daniel M. Pinkas Phoebe A. Rice Yufeng Tong Maya Topf Jonathan D. Walton Torsten Schwede 《Proteins》2019,87(12):1037-1057
The functional and biological significance of selected CASP13 targets are described by the authors of the structures. The structural biologists discuss the most interesting structural features of the target proteins and assess whether these features were correctly reproduced in the predictions submitted to the CASP13 experiment. 相似文献
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Maharjan S Aryal N Bhattarai S Koju D Lamichhane J Sohng JK 《Applied microbiology and biotechnology》2012,93(2):687-696
A number of structurally diverse natural products harboring pyrrole moieties possess a wide range of biological activities.
Studies on biosynthesis of pyrrole ring have shown that pyrrole moieties are derived from l-proline. Nargenicin A1, a saturated alicyclic polyketide from Nocardia sp. CS682, is a pyrrole-2-carboxylate ester of nodusmicin. We cloned and identified a set of four genes from Nocardia sp. CS682 that show sequence similarity to the respective genes involved in the biosynthesis of the pyrrole moieties of pyoluteorin
in Pseudomonas fluorescens, clorobiocin in Streptomyces roseochromogenes subsp. Oscitans, coumermycin A1 in Streptomyces rishiriensis, one of the pyrrole rings of undecylprodigiosin in Streptomyces coelicolor, and leupyrrins in Sorangium cellulosum. These genes were designated as ngnN4, ngnN5, ngnN3, and ngnN2. In this study, we presented the evidences that the pyrrole moiety of nargenicin A1 was also derived from l-proline by the coordinated action of three proteins, NgnN4 (proline adenyltransferase), NgnN5 (proline carrier protein),
and NgnN3 (flavine-dependent acyl-coenzyme A dehydrogenases). Biosynthesis of pyrrole moiety in nargenicin A1 is initiated by NgnN4 that catalyzes ATP-dependent activation of l-proline into l-prolyl-AMP, and the latter is transferred to NgnN5 to create prolyl-S-peptidyl carrier protein (PCP). Later, NgnN3 catalyzes the two-step oxidation of prolyl-S-PCP into pyrrole-2-carboxylate. Thus, this study presents another example of a pyrrole moiety biosynthetic pathway that uses
a set of three genes to convert l-proline into pyrrole-2-carboxylic acid moiety. 相似文献
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Severe attacks of bacterial blight were observed on young plants throughout the hazelnut growing areas in Chile. The incidence of the disease in nurseries and fields ranged from 60–90%. The causal agent was identified as Xanthomonas arboricola pv. corylina, based on phenotypic and genetic tests. 相似文献
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Stephanie L. Davis Nicholas A. Be Gyanu Lamichhane Sridhar Nimmagadda Martin G. Pomper William R. Bishai Sanjay K. Jain 《PloS one》2009,4(7)
Background
Bacteria can be selectively imaged in experimentally-infected animals using exogenously administered 1-(2′deoxy-2′-fluoro-β-D-arabinofuranosyl)-5-[125I]-iodouracil ([125I]-FIAU), a nucleoside analog substrate for bacterial thymidine kinase (TK). Our goal was to use this reporter and develop non-invasive methods to detect and localize Mycobacterium tuberculosis.Methodology/Principal Findings
We engineered a M. tuberculosis strain with chromosomally integrated bacterial TK under the control of hsp60 - a strong constitutive mycobacterial promoter. [125I]FIAU uptake, antimicrobial susceptibilities and in vivo growth characteristics were evaluated for this strain. Using single photon emission computed tomography (SPECT), M. tuberculosis Phsp60 TK strain was evaluated in experimentally-infected BALB/c and C3HeB/FeJ mice using the thigh inoculation or low-dose aerosol infection models. M. tuberculosis Phsp60 TK strain actively accumulated [125I]FIAU in vitro. Growth characteristics of the TK strain and susceptibility to common anti-tuberculous drugs were similar to the wild-type parent strain. M. tuberculosis Phsp60 TK strain was stable in vivo and SPECT imaging could detect and localize this strain in both animal models tested.Conclusion
We have developed a novel tool for non-invasive assessment of M. tuberculosis in live experimentally-infected animals. This tool will allow real-time pathogenesis studies in animal models of TB and has the potential to simplify preclinical studies and accelerate TB research. 相似文献27.
Paul J. Converse Kathleen D. Eisenach Sue A. Theus Eric L. Nuermberger Sandeep Tyagi Lan H. Ly Deborah E. Geiman Haidan Guo Scott T. Nolan Nicole C. Akar Lee G. Klinkenberg Radhika Gupta Shichun Lun Petros C. Karakousis Gyanu Lamichhane David N. McMurray Jacques H. Grosset William R. Bishai 《PloS one》2010,5(4)
Background
It has been hypothesized that the virulence of lab-passaged Mycobacterium tuberculosis and recombinant M. tuberculosis mutants might be reduced due to multiple in vitro passages, and that virulence might be augmented by passage of these strains through mice before quantitative virulence testing in the mouse or guinea pig aerosol models.Methodology/Principal Findings
By testing three M. tuberculosis H37Rv samples, one deletion mutant, and one recent clinical isolate for survival by the quantitative organ CFU counting method in mouse or guinea pig aerosol or intravenous infection models, we could discern no increase in bacterial fitness as a result of passaging of M. tuberculosis strains in mice prior to quantitative virulence testing in two animal models. Surface lipid expression as assessed by neutral red staining and thin-layer chromatography for PDIM analysis also failed to identify virulence correlates.Conclusions/Significance
These results indicate that animal passaging of M. tuberculosis strains prior to quantitative virulence testing in mouse or guinea pig models does not enhance or restore potency to strains that may have lost virulence due to in vitro passaging. It is critical to verify virulence of parental strains before genetic manipulations are undertaken and comparisons are made. 相似文献28.
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Adults of the human parasitic trematode Schistosoma mansoni, which causes
hepatosplenic/intestinal complications in humans, synthesize
glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1--
>3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now
report on our analyses of Lexand sLexexpression in S.haematobium and
S.japonicum, which are two other major species of human schistosomes that
cause disease, and the possible autoimmunity to these antigens in infected
individuals. Antigen expression was evaluated by both ELISA and Western
blot analyses of detergent extracts of parasites using monoclonal
antibodies. Several high molecular weight glycoproteins in both S.
haematobium and S. japonicum contain the Lexantigen, but no sialyl
Lexantigen was detected. In addition, sera from humans and rodents infected
with S.haematobium and S.japonicum contain antibodies reactive with Lex.
These results led us to investigate whether Lexantigens are expressed in
other helminths, including the parasitic trematode Fasciola hepatica , the
parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant
nematode Haemonchus contortus , and the free-living nematode Caenorhabditis
elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths.
Furthermore, none of the helminths, including schistosomes, express Lea,
Leb, Ley, or the H- type 1 antigen. However, several glycoproteins from all
helminths analyzed are bound by Lotus tetragonolobus agglutinin , which
binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which
binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be
unique among helminths in expressing the Lexantigen, whereas many different
helminths may express alpha1,3-fucosylated glycans and the LDN motif.
相似文献
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