Characterization and infectivity of a spontaneous variant isolated fromFrankia sp. WEY 0131391

1985 ◽  
Vol 87 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Willie L. Parson ◽  
Linda R. Robertson ◽  
Carolyn V. Carpenter
Keyword(s):  
Spontaneous Variant

scholarly journals Nucleotide sequence of an insertion sequence (IS) element identified in the T-DNA region of a spontaneous variant of the Ti-plasmid pTiT37

1986 ◽  
Vol 14 (16) ◽  
pp. 6699-6709 ◽  
Author(s):  
Jos Vanderleyden ◽  
Jos Desair ◽  
De Meirsman ◽  
Kris Michiels ◽  
August P. Van Gool ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Insertion Sequence ◽  
Ti Plasmid ◽  
Is Element ◽  
Spontaneous Variant

Production of curdlan-type polysaccharide by Alcaligenes faecalis in batch and continuous culture

1983 ◽  
Vol 29 (10) ◽  
pp. 1331-1338 ◽  
Author(s):  
K. Railton Phillips ◽  
J. Pik ◽  
H. G. Lawford ◽  
B. Lavers ◽  
A. Kligerman ◽  
...  
Keyword(s):  
Chemostat Culture ◽  
Product Yield ◽  
Alcaligenes Faecalis ◽  
Single Stage ◽  
Specific Rate ◽  
Continuous Cultures ◽  
Batch Cultures ◽  
Curdlan Production ◽  
Spontaneous Variant

The biosynthesis of a thermogelable, extracellular homo-β-(1 → 3)-glucan called "curdlan," has been studied in batch and continuous cultures of Alcaligenes faecalis var. myxogenes. Curdlan production is associated with the poststationary phase of a nitrogen-depleted, aerobic batch culture. Exopolymer is not detected in single-stage, carbon-limited continuous cultures but curdlan can be isolated from the effluent of a nitrogen-limited chemostat operating at a dilution rate (D) of < 0.1 h−1. A spontaneous variant of strain ATCC 21680 was isolated and found to be compatible with long-term, nitrogen-limited chemostat culture. The specific rate of curdlan production is approximately four times higher in poststationary batch cultures than in single-stage continuous fermentations. The product yield (Yp/s) associated with batch processing (nongrowing cultures) is approximately 0.5 g curdlan/g glucose, with CO2 being the only detectable by-product.

scholarly journals Colonial Morphology of Burkholderia cepacia Complex Genomovar III: Implications in Exopolysaccharide Production, Pilus Expression, and Persistence in the Mouse

2003 ◽  
Vol 71 (2) ◽  
pp. 904-909 ◽  
Author(s):  
Jacqueline W. Chung ◽  
Eleonora Altman ◽  
Terry J. Beveridge ◽  
David P. Speert
Keyword(s):  
Burkholderia Cepacia ◽  
Parent Strain ◽  
Pulmonary Infection ◽  
Burkholderia Cepacia Complex ◽  
Virulence Determinants ◽  
Genetic Typing ◽  
Exopolysaccharide Production ◽  
Colonial Morphology ◽  
Spontaneous Variant

ABSTRACT The purpose of this study was to determine the role of colonial morphology of Burkholderia cepacia complex (BCC) organisms in pathogenicity in a mouse model of pulmonary infection. BCC strain C1394 was rapidly cleared by leukopenic mice after intranasal challenge, whereas a spontaneous variant (C1394mp2) that was indistinguishable from the parent strain by genetic typing persisted in the lungs and differed in colonial morphology. The parent strain had a matte colonial phenotype, made scant exopolysaccharide (EPS), and was lightly piliated. The variant had a shiny phenotype, produced abundant EPS, and was heavily piliated. Matte to shiny colonial transformation was induced by growth at 42°C. Colonial morphology in the BCC strain variant was associated with persistence after pulmonary challenge and appeared to be correlated with the elaboration of putative virulence determinants.

Histoplasma capsulatum chemotypes I and II induce IL-8 secretion in lung epithelial cells in distinct manners

2020 ◽  
Vol 58 (8) ◽  
pp. 1169-1177 ◽  
Author(s):  
Cristiane Alcantara ◽  
Bruna Rocha Almeida ◽  
Bianca Carla Silva Campitelli Barros ◽  
Cristina Mary Orikaza ◽  
Marcos Sergio Toledo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Epithelial Cells ◽  
Cell Cultures ◽  
A549 Cell ◽  
Histoplasma Capsulatum ◽  
Specific Inhibitor ◽  
Lung Epithelial Cells ◽  
Wild Type ◽  
Lung Epithelial ◽  
Spontaneous Variant

Abstract The cell wall is one of the most important structures of pathogenic fungi, enabling initial interaction with the host and consequent modulation of immunological responses. Over the years, some researchers have shown that cell wall components of Histoplasma capsulatum vary among fungal isolates, and one of the major differences is the presence or absence of α-(1,3)-glucan, classifying wild-type fungi as chemotypes II or I, respectively. The present work shows that an isolate of H. capsulatum chemotype I induced lower levels of interleukin (IL)-8 secretion by the lung epithelial cell line A549, when compared to chemotype II yeasts. Thus, we expected that the absence of α-glucan in spontaneous variant yeasts, which were isolated from chemotype II cultures, would modify IL-8 secretion by A549 cells, but surprisingly, these fungi promoted similar levels of IL-8 secretion as their wild-type counterpart. Furthermore, when using a specific inhibitor for Syk activation, we observed that this inhibitor reduced IL-8 levels in A549 cell cultures infected with wild type chemotype I fungi. This inhibitor failed to reduce this cytokine levels in A549 cell cultures infected with chemotype II and their spontaneous variant yeasts, which also do not present α-glucan on their surface. The importance of SFKs and PKC δ in this event was also analyzed. Our results show that different isolates of H. capsulatum modulate distinct cell signaling pathways to promote cytokine secretion in host epithelial cells, emphasizing the existence of various mechanisms for Histoplasma pathogenicity.

Ventricular ectopic activity with spontaneous variant angina: Frequency and relation to transient ST segment deviation

1985 ◽  
Vol 110 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Gregory I. Gabliani ◽  
Michael D. Winniford ◽  
Kay L. Fulton ◽  
Stacey M. Johnson ◽  
David R. Mauritson ◽  
...  
Keyword(s):  
Variant Angina ◽  
Ectopic Activity ◽  
Ventricular Ectopic Activity ◽  
St Segment ◽  
Angina Frequency ◽  
Spontaneous Variant

Characterization and infectivity of a spontaneous variant isolated from Frankia sp. WEY 0131391

1985 ◽  
pp. 31-42
Author(s):  
Willie L. Parson ◽  
Linda R. Robertson ◽  
Carolyn V. Carpenter
Keyword(s):  
Spontaneous Variant

Expression of dibenzothiophene-degradative genes in two Pseudomonas species

1990 ◽  
Vol 36 (10) ◽  
pp. 718-724 ◽  
Author(s):  
J. M. Foght ◽  
D. W. S. Westlake
Keyword(s):  
Salicylic Acid ◽  
Dna Hybridization ◽  
Type Strain ◽  
Wild Type Strain ◽  
Carbon Sources ◽  
Wild Type ◽  
Naphthalene Degradation ◽  
Pseudomonas Species ◽  
Genes Encoding ◽  
Spontaneous Variant

The genes encoding dibenzothiophene (DBT) degradation in Pseudomonas alcaligenes strain DBT2 were cloned into plasmid pC1 by other workers. This plasmid was conjugally transferred into a spontaneous variant of Pseudomonas sp. HL7b (designated HL7bR) incapable of oxidizing DBT (Dbt− phenotype). Acquisition of plasmid pC1 simultaneously restored oxidation of DBT and naphthalene to the transconjugant, although the primary DBT metabolite produced by transconjugant HL7bR(pC1) corresponded to that produced by wild-type strain DBT2 rather than that from wild-type strain HL7b. Inducers of the naphthalene pathway (naphthalene, salicylic acid, and 2-aminobenzoate) stimulated DBT oxidation in transconjugant HL7bR(pC1) when present at 0.1 mM concentrations but had no effect on wild-type strain HL7b. Higher concentrations (5 mM) of salicylic acid and naphthalene were inhibitory to DBT oxidation in all strains. DNA–DNA hybridization was not observed between plasmid pC1 and genomic DNA from strains HL7b or HL7bR, nor between authentic naphthalene-degradative genes (plasmid NAH2) and either plasmid pC1 or strain HL7b, despite the observation that the degradative genes encoded on plasmid pC1 functionally resembled broad-specificity naphthalene-degradative genes. Transconjugant HL7bR(pC1) is a mosaic of the parental types regarding DBT metabolite production, regulation, and use of carbon sources. Key words: dibenzothiophene, naphthalene, degradation, regulation, hybridization.

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