Background: B. bronchiseptica infections are usually associated with wild or domesticated animals, but infrequently with humans. A recent phylogenetic analysis distinguished two distinct B. bronchiseptica subpopulations, designated complexes I and IV. Complex IV isolates appear to have a bias for infecting humans; however, little is known regarding their epidemiology, virulence properties, or comparative genomics.
Results: Here we report a characterization of the virulence of human-associated complex IV B. bronchiseptica strains. In in vitro cytotoxicity assays, complex IV strains showed increased cytotoxicity in comparison to a panel of complex I strains. Some complex IV isolates were remarkably cytotoxic, resulting in LDH release levels in A549 cells that were 10- to 20-fold greater than complex I strains. In vivo, a subset of complex IV strains was found to be hypervirulent, with an increased ability to cause lethal pulmonary infections in mice. Hypercytotoxicity in vitro and hypervirulence in vivo were both dependent on the activity of the bsc T3SS and the BteA effector. To clarify differences between lineages, representative complex IV isolates were sequenced and their genomes were compared to complex I isolates. Although our analysis showed there were no genomic sequences that can be considered unique to complex IV strains, there were several loci that were predominantly found in complex IV isolates.
Conclusion: Our observations reveal a T3SS-dependent hypervirulence phenotype in human-associated complex IV isolates, highlighting the need for further studies on the epidemiology and evolutionary dynamics of this B. bronchiseptica lineage.
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http://dx.doi.org/10.1186/1471-2180-12-167 | DOI Listing |
Photosynth Res
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State Key Laboratory of Forage Breeding-by-Design and Utilization, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
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View Article and Find Full Text PDFPsychotherapy (Chic)
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Outcome Referrals Inc.
Complementing the oft-studied construct of isolation, research has increasingly focused on existential isolation (EI), or the subjective feeling of separateness in one's experience. In the clinical realm, several studies have demonstrated that higher EI is associated with more severe mental health problems at a single cross-section of time. Moreover, one study showed that higher pretreatment EI predicted worse psychotherapy outcomes.
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January 2025
W Liu, Shenzhen Key Laboratory of Fertility Regulation, the University of Hong Kong-Shenzhen Hospital, Shenzhen, China.
Serum progesterone may increase prior to ovulation trigger in in vitro fertilization patients, jeopardizing endometrial receptivity and therefore live birth rate. Recombinant FSH (rFSH) promotes progesterone production from human granulosa cells. Yet, the role of FSH on progesterone production need deeper exploration.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Technical University of Munich, Department of Chemistry, Lichtenbergstr. 4, D-85747, Garching, Germany.
Despite the first examples being isolated more than two decades ago, little is known about the redox chemistry of stable phosphacyclic biradicaloids. Here, we demonstrate that a biradicaloid featuring a diphosphaindenyl backbone is able to undergo both oxidation and reduction reactions. One-electron oxidation results in the formation of a dicationic cage compound structurally related to an isomer of hypostrophene (CH).
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Pennsylvania, 231 S 34th St, Philadelphia, Pennsylvania 19104, United States.
Molecular Zr phosphides are extremely rare, with no examples containing a one-coordinated and terminal triple-bonded phosphorus atom. We report here an isolable and relatively stable Zr phosphide complex, [(PN)Zr≡P{μ-Na(OEt)}] (), stemming from a cyclometalated Zr-hydride, [(PN)(PN')Zr(H)] (), and NaPH. Complex is prepared from two- or one-electron reductions of precursors [(PN)ZrCl] () or metastable Zr[(PN)ZrCl], respectively.
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