Fluoroglycoproteins by Copper-Free Strain-Promoted Azide–Alkyne Cycloaddition

Aspergillus and Pseudomonas compete in nature, and are the commonest bacterial and fungal pathogens in some clinical settings, such as the cystic fibrosis lung. Virus infections of fungi occur naturally. Effects on fungal physiology need delineation. A common reference Aspergillus fumigatus strain, long studied in two (of many) laboratories, was found infected with the AfuPmV-1 virus. One isolate was cured of virus, producing a virus-free strain. Virus from the infected strain was purified and used to re-infect three subcultures of the virus-free fungus, producing six fungal strains, otherwise isogenic. They were studied in intermicrobial competition with Pseudomonasaeruginosa. Pseudomonas culture filtrates inhibited forming or preformed Aspergillus biofilm from infected strains to a greater extent, also seen when Pseudomonas volatiles were assayed on Aspergillus. Purified iron-chelating Pseudomonas molecules, known inhibitors of Aspergillus biofilm, reproduced these differences. Iron, a stimulus of Aspergillus, enhanced the virus-free fungus, compared to infected. All infected fungal strains behaved similarly in assays. We show an important consequence of virus infection, a weakening in intermicrobial competition. Viral infection may affect the outcome of bacterial–fungal competition in nature and patients. We suggest that this occurs via alteration in fungal stress responses, the mechanism best delineated here is a result of virus-induced altered Aspergillus iron metabolism.

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Genetic Characterization of the Carotenoid Biosynthetic Pathway in Methylobacterium extorquens AM1 and Isolation of a Colorless Mutant

Applied and Environmental Microbiology ◽

10.1128/aem.69.12.7563-7566.2003 ◽

2003 ◽

Vol 69 (12) ◽

pp. 7563-7566 ◽

Cited By ~ 29

Author(s):

Stephen J. Van Dien ◽

Christopher J. Marx ◽

Brooke N. O'Brien ◽

Mary E. Lidstrom

Keyword(s):

Biosynthetic Pathway ◽

Genetic Characterization ◽

Carotenoid Biosynthesis ◽

Biosynthesis Pathway ◽

Wild Type ◽

Methylobacterium Extorquens ◽

Growth Properties ◽

Carotenoid Biosynthesis Pathway ◽

Free Strain

ABSTRACT Genomic searches were used to reconstruct the putative carotenoid biosynthesis pathway in the pink-pigmented facultative methylotroph Methylobacterium extorquens AM1. Four genes for putative phytoene desaturases were identified. A colorless mutant was obtained by transposon mutagenesis, and the insertion was shown to be in one of the putative phytoene desaturase genes. Mutations in the other three did not affect color. The tetracycline marker was removed from the original transposon mutant, resulting in a pigment-free strain with wild-type growth properties useful as a tool for future experiments.

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Actuation of fluidic flexible matrix composites in structural media

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x11428676 ◽

2011 ◽

Vol 23 (3) ◽

pp. 269-278 ◽

Cited By ~ 6

Author(s):

Bin Zhu ◽

Christopher D Rahn ◽

Charles E Bakis

Keyword(s):

Matrix Material ◽

Unit Cell ◽

Analytical Models ◽

Thin Wall ◽

Matrix Composites ◽

Soft Matrix ◽

Structural Applications ◽

Order Of Magnitude ◽

Flexible Matrix Composite ◽

Free Strain

Fluidic flexible matrix composite (F2MC) tubes have been shown to provide actuation and stiffness change in applications that require isolated tubes or multiple tubes embedded in a soft matrix. Structural applications often require stiff and strong composites, however, so this article addresses the actuation performance of F2MC tubes embedded in structural media. Two analytical models are developed based on Lekhnitskii’s solutions for a homogeneous orthotropic cylinder with axial force and pressure loading. These unit cell models are cylindrical and bilayer with the inner layer being a thick-walled F2MC tube and the outer layer representing the surrounding rigid composite and are composed of either homogeneous epoxy or a second FMC layer made with stiffer matrix material. The models are validated using ABAQUS. Free strain and blocked force are calculated for a variety of unit cell designs. The analytical results show that actuation performance is generally reduced compared to that of an isolated F2MC tube due to the radial and longitudinal constraints imposed by the surrounding structural medium. The free strain is generally two orders of magnitude smaller for an F2MC tube in structural media, requiring higher actuation pressures for bilayer F2MC structures. The blocking force of F2MC in either epoxy or composite is roughly an order of magnitude smaller than that of an isolated F2MC tube. The analysis shows a great degree of tailorability in actuation properties, so that the F2MC tube can be designed to minimize these differences. Higher actuation performance is achieved, for example, with a thick-walled F2MC tube, as opposed to the thin wall that maximizes performance in an isolated F2MC tube.

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Latent Haemobartonella muris infection: its transmission and decline in an inbred, ectoparasite-free strain of Wistar rat

Parasitology ◽

10.1017/s0031182000053129 ◽

1975 ◽

Vol 71 (1) ◽

pp. 35-40 ◽

Cited By ~ 1

Author(s):

Roberta Bartlett ◽

Phyllis Pease

Keyword(s):

Inbred Line ◽

Experimental Infection ◽

Wistar Rats ◽

Latent Infection ◽

Wistar Rat ◽

Wild Rats ◽

Free Strain

Ectoparasite-free, SPF Italian Wistar rats were consistently found to carry a latent infection with Haemobartonella muris, activable by splen ectomy. In an inbred line this diminished and eventually ceased in six generations. Experimental infection from wild rats demonstrated that this was not apparently due to immunity.

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Construction of the plasmid-free strain for human growth hormone production

Biochimie ◽

10.1016/j.biochi.2016.08.007 ◽

2016 ◽

Vol 128-129 ◽

pp. 148-153

Author(s):

A.A. Schulga ◽

P.V. Mechev ◽

M.P. Kirpichnikov ◽

K.G. Skryabin ◽

S.M. Deyev

Keyword(s):

Growth Hormone ◽

Human Growth Hormone ◽

Human Growth ◽

Hormone Production ◽

Free Strain

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Phenotypic and Molecular Biological Analysis of Polymycovirus AfuPmV-1M From Aspergillus fumigatus: Reduced Fungal Virulence in a Mouse Infection Model

Frontiers in Microbiology ◽

10.3389/fmicb.2020.607795 ◽

2020 ◽

Vol 11 ◽

Author(s):

Azusa Takahashi-Nakaguchi ◽

Erika Shishido ◽

Misa Yahara ◽

Syun-ichi Urayama ◽

Akihiro Ninomiya ◽

...

Keyword(s):

Aspergillus Fumigatus ◽

Sequence Similarity ◽

Infection Model ◽

Dsrna Segment ◽

High Sequence Similarity ◽

Fungal Virulence ◽

Mouse Infection Model ◽

Mouse Infection ◽

Macrophage Phagocytosis ◽

Free Strain

The filamentous fungal pathogen Aspergillus fumigatus is one of the most common causal agents of invasive fungal infection in humans; the infection is associated with an alarmingly high mortality rate. In this study, we investigated whether a mycovirus, named AfuPmV-1M, can reduce the virulence of A. fumigatus in a mouse infection model. AfuPmV-1M has high sequence similarity to AfuPmV-1, one of the polymycovirus that is a capsidless four-segment double-stranded RNA (dsRNA) virus, previously isolated from the genome reference strain of A. fumigatus, Af293. However, we found the isolate had an additional fifth dsRNA segment, referred to as open reading frame 5 (ORF5), which has not been reported in AfuPmV-1. We then established isogenic lines of virus-infected and virus-free A. fumigatus strains. Mycovirus infection had apparent influences on fungal phenotypes, with the virus-infected strain producing a reduced mycelial mass and reduced conidial number in comparison with these features of the virus-free strain. Also, resting conidia of the infected strain showed reduced adherence to pulmonary epithelial cells and reduced tolerance to macrophage phagocytosis. In an immunosuppressed mouse infection model, the virus-infected strain showed reduced mortality in comparison with mortality due to the virus-free strain. RNA sequencing and high-performance liquid chromatography (HPLC) analysis showed that the virus suppressed the expression of genes for gliotoxin synthesis and its production at the mycelial stage. Conversely, the virus enhanced gene expression and biosynthesis of fumagillin. Viral RNA expression was enhanced during conidial maturation, conidial germination, and the mycelial stage. We presume that the RNA or translation products of the virus affected fungal phenotypes, including spore formation and toxin synthesis. To identify the mycovirus genes responsible for attenuation of fungal virulence, each viral ORF was ectopically expressed in the virus-free KU strain. We found that the expression of ORF2 and ORF5 reduced fungal virulence in the mouse model. In addition, ORF3 affected the stress tolerance of host A. fumigatus in culture. We hypothesize that the respective viral genes work cooperatively to suppress the pathogenicity of the fungal host.

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Analysis of Mechanisms Involved in the Cucumber mosaic virus Satellite RNA-mediated Transgenic Resistance in Tomato Plants

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2004.17.1.98 ◽

2004 ◽

Vol 17 (1) ◽

pp. 98-108 ◽

Cited By ~ 29

Author(s):

Fabrizio Cillo ◽

Mariella M. Finetti-Sialer ◽

Maria A. Papanice ◽

Donato Gallitelli

Keyword(s):

Cucumber Mosaic Virus ◽

Mosaic Virus ◽

Rna Silencing ◽

Resistance Mechanism ◽

Degradation Process ◽

Transgenic Tomato ◽

Satellite Rna ◽

Total Recovery ◽

Tomato Plants ◽

Free Strain

Transgenic tomato (Lycopersicon esculentum Mill. cv. UC82) plants expressing a benign variant of Cucumber mosaic virus satellite RNA (CMV Tfn-satRNA) were generated. The transformed plants did not produce symptoms when challenged with a satRNA-free strain of CMV (CMV-FL). The same plant lines initially were susceptible to necrosis elicited by a CMV strain supporting a necrogenic variant of satRNA (CMV-77), but a phenotype of total recovery from the necrosis was observed in the newly developing leaves. The features of the observed resistance were analyzed and are consistent with two different mechanisms of resistance. In transgenic plants inoculated with CMV-FL strain, the symptomless phenotype was correlated to the down-regulation of CMV by Tfn-satRNA, amplified from the transgene transcripts, as the first resistance mechanism. On the other hand, the delayed resistance to CMV-77 in transgenic tomato lines was mediated by a degradation process that targets satRNAs in a sequence-specific manner. Evidence is provided for a correlation between a reduced accumulation level of transgenic messenger Tfn-satRNA, the accumulation of small (approximately 23 nucleotides) RNAs with sequence homology to satRNAs, the progressively reduced accumulation of 77-satRNA in infected tissues, and the transition in infected plants from diseased to healthy. Thus, events leading to the degradation of satRNA sequences indicate a role for RNA silencing as the second mechanism determining resistance of transgenic tomato lines.

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The 〈111〉 Elliptic Inclusion in an Anisotropic Solid of Cubic Symmetry

Journal of Applied Mechanics ◽

10.1115/1.3162093 ◽

1982 ◽

Vol 49 (2) ◽

pp. 353-360 ◽

Cited By ~ 1

Author(s):

H. C. Yang ◽

Y. T. Chou

Keyword(s):

Stress Field ◽

Uniform Stress ◽

Elliptic Inclusion ◽

Cubic Symmetry ◽

Elastic Fields ◽

Closed Form Solutions ◽

Strain Transformation ◽

Anisotropic Solid ◽

Uniform Stress Field ◽

Free Strain

This paper deals with a generalized plane problem in which a uniform stress-free strain transformation takes place in the region of an elliptic cyclinder (the inclusion) oriented in the 〈111〉 direction in an anisotropic solid of cubic symmetry. Closed-form solutions for the elastic fields and the strain energies are presented. The perturbation of an otherwise uniform stress field due to a 〈111〉 elliptic inhomogeneity is also treated including two extreme cases, elliptic cavities and rigid inhomogeneities.

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