Serologic Evidence for Effective Production of Cytolysin A in Salmonella enterica Serovars Typhi and Paratyphi A during Human Infection

ABSTRACT ClyASTy and ClyASPaA are closely related pore-forming cytolysins of Salmonella enterica serovars Typhi and Paratyphi A whose expression is strongly repressed under standard in vitro growth conditions. We show here that human infections by these pathogens cause a specific antibody response to ClyA, indicating effective toxin production during infection.

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Integration host factor alleviates H-NS silencing of the Salmonella enterica serovar Typhimurium master regulator of SPI1, hilA

Microbiology ◽

10.1099/mic.0.049197-0 ◽

2011 ◽

Vol 157 (9) ◽

pp. 2504-2514 ◽

Cited By ~ 22

Author(s):

Mário H. Queiroz ◽

Cristina Madrid ◽

Sònia Paytubi ◽

Carlos Balsalobre ◽

Antonio Juárez

Keyword(s):

Stationary Phase ◽

Salmonella Enterica ◽

Growth Conditions ◽

Integration Host Factor ◽

Band Shift ◽

Global Regulators ◽

Serovar Typhimurium ◽

Associated Proteins ◽

Transcription Data

Coordination of the expression of Salmonella enterica invasion genes on Salmonella pathogenicity island 1 (SPI1) depends on a complex circuit involving several regulators that converge on expression of the hilA gene, which encodes a transcriptional activator (HilA) that modulates expression of the SPI1 virulence genes. Two of the global regulators that influence hilA expression are the nucleoid-associated proteins Hha and H-NS. They interact and form a complex that modulates gene expression. A chromosomal transcriptional fusion was constructed to assess the effects of these modulators on hilA transcription under several environmental conditions as well as at different stages of growth. The results obtained showed that these proteins play a role in silencing hilA expression at both low temperature and low osmolarity, irrespective of the growth phase. H-NS accounts for the main repressor activity. At high temperature and osmolarity, H-NS-mediated silencing completely ceases when cells enter the stationary phase, and hilA expression is induced. Mutants lacking IHF did not induce hilA in cells entering the stationary phase, and this lack of induction was dependent on the presence of H-NS. Band-shift assays and in vitro transcription data showed that for hilA induction under certain growth conditions, IHF is required to alleviate H-NS-mediated silencing.

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Influence of in vitro growth conditions in the production of defence compounds in Mentha pulegium L.

Phytochemistry Letters ◽

10.1016/j.phytol.2014.03.007 ◽

2014 ◽

Vol 8 ◽

pp. 233-244 ◽

Cited By ~ 8

Author(s):

Khadija H. Benlarbi ◽

Nouriddine Elmtili ◽

Francisco A. Macías ◽

Juan Carlos G. Galindo

Keyword(s):

Growth Conditions ◽

In Vitro Growth ◽

Mentha Pulegium

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Terminal Deoxynucleotidyl Transferase Is Not Required for Antibody Response to Polysaccharide Vaccines againstStreptococcus pneumoniaeandSalmonella entericaSerovar Typhi

Infection and Immunity ◽

10.1128/iai.00211-18 ◽

2018 ◽

Vol 86 (9) ◽

Author(s):

Vivek Belde ◽

Matthew P. Cravens ◽

Dania Gulandijany ◽

Justin A. Walker ◽

Isabel Palomo-Caturla ◽

...

Keyword(s):

Antibody Response ◽

B Cell ◽

Salmonella Enterica ◽

Passive Immunization ◽

Terminal Deoxynucleotidyl Transferase ◽

Human Infants ◽

Content Type ◽

Serovar Typhimurium

ABSTRACTB cell antigen receptor (BCR) diversity increases by several orders of magnitude due to the action of terminal deoxynucleotidyl transferase (TdT) during V(D)J recombination. Unlike adults, infants have limited BCR diversity, in part due to reduced expression of TdT. Since human infants and young mice respond poorly to polysaccharide vaccines, such as the pneumococcal polysaccharide vaccine Pneumovax23 and Vi polysaccharide (ViPS) ofSalmonella entericaserovar Typhi, we tested the contribution of TdT-mediated BCR diversity in response to these vaccines. We found that TdT+/−and TdT−/−mice generated comparable antibody responses to Pneumovax23 and survivedStreptococcus pneumoniaechallenge. Moreover, passive immunization of B cell-deficient mice with serum from Pneumovax23-immunized TdT+/−or TdT−/−mice conferred protection. TdT+/−and TdT−/−mice generated comparable levels of anti-ViPS antibodies and antibody-dependent, complement-mediated bactericidal activity againstS. Typhiin vitro. To test the protective immunity conferred by ViPS immunizationin vivo, TdT+/−and TdT−/−mice were challenged with a chimericSalmonella entericaserovar Typhimurium strain expressing ViPS, since mice are nonpermissive hosts forS. Typhi infection. Compared to their unimmunized counterparts, immunized TdT+/−and TdT−/−mice challenged with ViPS-expressingS. Typhimurium exhibited a significant reduction in the bacterial burden and liver pathology. These data suggest that the impaired antibody response to the Pneumovax23 and ViPS vaccines in the young is not due to limited TdT-mediated BCR diversification.

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Optimization of in vitro growth conditions of Pyrenophora teres for production of the phytotoxin aspergillomarasmine A

Physiological and Molecular Plant Pathology ◽

10.1006/pmpp.2002.0383 ◽

2002 ◽

Vol 60 (3) ◽

pp. 131-140 ◽

Cited By ~ 9

Author(s):

I. Weiergang ◽

H.J. Lyngs JØrgensen ◽

I.M. MØller ◽

P. Friis ◽

V. Smedegaard-Petersen

Keyword(s):

Growth Conditions ◽

Pyrenophora Teres ◽

In Vitro Growth

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Glutamine-enriched enteral nutrition increases in vitro interferon-gamma production but does not influence the in vivo specific antibody response to KLH after severe trauma. A prospective, double blind, randomized clinical study

Clinical Nutrition ◽

10.1016/j.clnu.2003.09.002 ◽

2004 ◽

Vol 23 (3) ◽

pp. 391-400 ◽

Cited By ~ 16

Author(s):

Petra G Boelens ◽

Alexander P.J Houdijk ◽

Johanna C.M Fonk ◽

Juan C Puyana ◽

Henk J.Th.M Haarman ◽

...

Keyword(s):

Clinical Study ◽

Enteral Nutrition ◽

Antibody Response ◽

Interferon Gamma ◽

Severe Trauma ◽

Double Blind ◽

Specific Antibody Response ◽

Randomized Clinical Study

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Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models

Journal of Virology ◽

10.1128/jvi.00451-20 ◽

2020 ◽

Vol 94 (17) ◽

Author(s):

Jessica A. Belser ◽

Xiangjie Sun ◽

Nicole Brock ◽

Claudia Pappas ◽

Joanna A. Pulit-Penaloza ◽

...

Keyword(s):

Influenza A ◽

Human Infection ◽

Influenza Viruses ◽

Human Populations ◽

Human Respiratory Tract ◽

Live Bird Markets ◽

Human Infections ◽

Live Bird

ABSTRACT Low-pathogenicity avian influenza A(H9N2) viruses, enzootic in poultry populations in Asia, are associated with fewer confirmed human infections but higher rates of seropositivity compared to A(H5) or A(H7) subtype viruses. Cocirculation of A(H5) and A(H7) viruses leads to the generation of reassortant viruses bearing A(H9N2) internal genes with markers of mammalian adaptation, warranting continued surveillance in both avian and human populations. Here, we describe active surveillance efforts in live poultry markets in Vietnam in 2018 and compare representative viruses to G1 and Y280 lineage viruses that have infected humans. Receptor binding properties, pH thresholds for HA activation, in vitro replication in human respiratory tract cells, and in vivo mammalian pathogenicity and transmissibility were investigated. While A(H9N2) viruses from both poultry and humans exhibited features associated with mammalian adaptation, one human isolate from 2018, A/Anhui-Lujiang/39/2018, exhibited increased capacity for replication and transmission, demonstrating the pandemic potential of A(H9N2) viruses. IMPORTANCE A(H9N2) influenza viruses are widespread in poultry in many parts of the world and for over 20 years have sporadically jumped species barriers to cause human infection. As these viruses continue to diversify genetically and antigenically, it is critical to closely monitor viruses responsible for human infections, to ascertain if A(H9N2) viruses are acquiring properties that make them better suited to infect and spread among humans. In this study, we describe an active poultry surveillance system established in Vietnam to identify the scope of influenza viruses present in live bird markets and the threat they pose to human health. Assessment of a recent A(H9N2) virus isolated from an individual in China in 2018 is also reported, and it was found to exhibit properties of adaptation to humans and, importantly, it shows similarities to strains isolated from the live bird markets of Vietnam.

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Influence of in vitro growth conditions on the photosynthesis and survival of Castanea sativa plantlets during ex vitro transfer

Plant Growth Regulation ◽

10.1007/s10725-014-9965-1 ◽

2014 ◽

Vol 75 (3) ◽

pp. 625-639 ◽

Cited By ~ 8

Author(s):

Patricia L. Sáez ◽

León A. Bravo ◽

Mirtha I. Latsague ◽

Marcelo J. Toneatti ◽

Rafael E. Coopman ◽

...

Keyword(s):

Castanea Sativa ◽

Growth Conditions ◽

In Vitro Growth ◽

Ex Vitro ◽

Ex Vitro Transfer

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Polynucleotide Phosphorylase Negatively Controls spv Virulence Gene Expression in Salmonella enterica

Infection and Immunity ◽

10.1128/iai.74.2.1243-1254.2006 ◽

2006 ◽

Vol 74 (2) ◽

pp. 1243-1254 ◽

Cited By ~ 49

Author(s):

Sofia Eriksson Ygberg ◽

Mark O. Clements ◽

Anne Rytkönen ◽

Arthur Thompson ◽

David W. Holden ◽

...

Keyword(s):

Salmonella Enterica ◽

Cold Shock ◽

Virulence Gene ◽

Growth Conditions ◽

Polynucleotide Phosphorylase ◽

Virulence Gene Expression ◽

Cold Shock Response ◽

Serovar Typhimurium ◽

Whole Genome Microarray

ABSTRACT Mutational inactivation of the cold-shock-associated exoribonuclease polynucleotide phosphorylase (PNPase; encoded by the pnp gene) in Salmonella enterica serovar Typhimurium was previously shown to enable the bacteria to cause chronic infection and to affect the bacterial replication in BALB/c mice (M. O. Clements et al., Proc. Natl. Acad. Sci. USA 99:8784-8789, 2002). Here, we report that PNPase deficiency results in increased expression of Salmonella plasmid virulence (spv) genes under in vitro growth conditions that allow induction of spv expression. Furthermore, whole-genome microarray-based transcriptome analyses of bacteria growing inside murine macrophage-like J774.A.1 cells revealed six genes as being significantly up-regulated in the PNPase-deficient background, which included spvABC, rtcB, entC, and STM2236. Mutational inactivation of the spvR regulator diminished the increased expression of spv observed in the pnp mutant background, implying that PNPase acts upstream of or at the level of SpvR. Finally, competition experiments revealed that the growth advantage of the pnp mutant in BALB/c mice was dependent on spvR as well. Combined, our results support the idea that in S. enterica PNPase, apart from being a regulator of the cold shock response, also functions in tuning the expression of virulence genes and bacterial fitness during infection.

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