55 research outputs found
Two Different Species of Mycoplasma Endosymbionts Can Influence Trichomonas vaginalis Pathophysiology
No full textTrichomonas vaginalis can host the endosymbiont Mycoplasma hominis, an opportunistic pathogenic bacterium capable of modulating T. vaginalis pathobiology. Recently, a new noncultivable mycoplasma, “Candidatus Mycoplasma girerdii,” has been shown to be closely associated with women affected by trichomoniasis, suggesting a biological association. Although several features of “Ca. M. girerdii” have been investigated through genomic analysis, the nature of the potential T. vaginalis-“Ca. M. girerdii” consortium and its impact on the biology and pathogenesis of both microorganisms have not yet been explored. Here, we investigate the association between “Ca. M. girerdii” and T. vaginalis isolated from patients affected by trichomoniasis, demonstrating their intracellular localization. By using an in vitro model system based on single- and double-Mycoplasma infection of Mycoplasma-free isogenic T. vaginalis, we investigated the ability of the protist to establish a relationship with the bacteria and impact T. vaginalis growth. Our data indicate likely competition between M. hominis and “Ca. M. girerdii” while infecting trichomonad cells. Comparative dual-transcriptomics data showed major shifts in parasite gene expression in response to the presence of Mycoplasma, including genes associated with energy metabolism and pathogenesis. Consistent with the transcriptomics data, both parasite-mediated hemolysis and binding to host epithelial cells were significantly upregulated in the presence of either Mycoplasma species. Taken together, these results support a model in which this microbial association could modulate the virulence of T. vaginalis
Consolidation and strength development of soft mud deposits by horizontal drainage
No full textEnvironmental Fluid Mechanic
Formation of the Zeebrugge coastal turbidity maximum: The role of uncertainty in near-bed exchange processes
No full textDespite availability of a large amount of observational data and modelling studies, the mechanisms maintaining the Turbidity Maximum in the Belgian-Dutch coastal zone around the port of Zeebrugge (Belgium) are insufficiently understood. In order to better understand the dynamics of this turbidity maximum we examine the role of baroclinic (salinity and sediment-induced) processes and local sediment sources on the formation and persistence of the turbidity maximum through two different numerical model approaches. One model approach allows erosion of the highly compacted muddy seabed, serving as a sediment source, in line with observations of bed level change over several decades. The other approach reduces the exchange between the bed and the water column, to mimic the formation of highly concentrated near-bed suspensions with concentrations of several g/l observed around the port of Zeebrugge. Both model approaches are calibrated to various sources of available data (in situ sediment concentration observations, satellite image, bed level changes, mud content and dredging data), which they reproduce comparably well. However, reducing the water-bed exchange strengthens sediment convergence in the turbidity maximum, whereas the sediment source leads to sediment export. With the available data, it is difficult to determine which of the approaches is more realistic. Apparently, the lack of knowledge on near-bed exchange processes introduces an important source of uncertainty which cannot be adequately addressed with currently available observations. This work therefore shows that more quantitative knowledge on water-bed exchange processes in turbid marine environments is needed. It is further hypothesized that the large-scale erosion of the muddy seabed following the extension the port of Zeebrugge in the early 1980's brought such a large amount of sediment in suspension (50–100 million ton) that sediment convergence was strengthened. This increasing sediment convergence introduces a positive feedback mechanism that maintains sediment in the Turbidity Maximum, or even strengthens it. The high sediment concentrations observed today may therefore be a long-term effect of port construction carried out decades earlier.Environmental Fluid Mechanic
Unique strategies of “<i>Ca</i>. M. girerdii”.
No full text<p>Putative transporters, enzymes involved in carbohydrate metabolism and virulence factors are represented in red for “<i>Ca</i>. M. girerdii”. Comparisons with other genital mycoplasmas are indicated with color-coded boxes: <i>M. genitalium</i> (MG, blue) <i>U. parvum</i> (UP, green) and <i>M. hominis</i> (MH, purple). Arrows indicate direction of transport. Light gray arrows represent metabolic strategies unique to other genital mycoplasma. Metabolic reconstruction was performed using ASGARD and careful inspection of manual annotations.</p
Expanded “<i>Ca</i>. M. girerdii” BspA-like protein family.
No full text<p>The diverse family of 26 BspA-like protein family members from the “<i>Ca</i>. M. girerdii” strain VCU_M1 is depicted in panel (A). Predicted transmembrane domains and TpLRR domains are represented. An alignment of TpLRR domains from <i>Tannerella forsythia</i> BspA (AAC82625.1, bases 382–1347), “<i>Ca</i>. M. girerdii” strain VCU_M1 MGM1_3780 (bases 449–782) and <i>T.vaginalis</i> BspA-like TVAG_495790 (XP_001327783.1, bases 112–1077) is shown in panel (B).</p
Representation of “<i>Ca.</i> M. girerdii” genomes.
No full text<p>A circular representation of the “<i>Ca.</i> M. girerdii” reference genome (strain VCU_M1) assembled from metagenomic sequences from a mid-vaginal sample. Position 1 is set to the start of the <i>dnaA</i> gene. Outermost circles (1–3) show the alignment (97% or greater identity) of contigs of three different strains from metagenomic assemblies from mid-vaginal samples containing high proportions of “<i>Ca</i>. M. girerdii”. Circle 4 (red) represents the reference strain (VCU_M1). Circles 5 (dark red) and 6 (blue) represent the predicted coding sequences in the forward and reverse orientations respectively. Circle 7 (black) shows the GC content, and circle 8 shows GC skew (pink (-), green (+)).</p
Characteristics of 73 “<i>Ca</i>. M. girerdii” positive vaginal samples.
No full text<p>“<i>Ca</i>. M. girerdii” was detected in the mid-vaginal microbiome profile at 0.1% or more of total reads. (ND, not determined; AMB, ambiguous; N/A, not applicable; NT, no type).</p><p>* Recruited from Labor & Delivery Unit.</p>†<p><i> “Ca.</i> M. girerdii<i>”</i> sequenced genomes VCU-M1, VCU-JB1, VCU-PA1 and VCU-G1 in listed order.</p>1,2,3<p> Three “<i>Ca</i>. M. girerdii” positive samples were from women who enrolled in the study more than once. VCU_GF83 was collected 424 days after VCU_NT73; VCU_NT58 was collected 246 days after VCU_NT70; VCU_NT77 was collected 117 days after VCU_RQ48.</p><p>Characteristics of 73 “<i>Ca</i>. M. girerdii” positive vaginal samples.</p
Phylogenetic Tree based on inferred amino acid sequences confirms placement of “<i>Ca.</i> M. girerdii” in the Pneumoniae group.
No full text<p>“<i>Ca</i>. M. girerdii” is located within the Pneumoniae group, denoted in green, in a subclade along with the <i>Ureaplasma</i> species, <i>M. iowae</i> and <i>M. penetrans</i>. The tree was inferred using amino acid sequences of 57 orthologs (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110943#pone.0110943.s008" target="_blank">Tables S4</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110943#pone.0110943.s009" target="_blank">S5</a>, and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110943#pone.0110943.s010" target="_blank">S6</a>). Numbers at nodes correspond to the support values from 1,000 bootstrap replicates.</p
Cluster analysis of mid-vaginal samples positive for “<i>Ca</i>. M. girerdii”.
No full text<p>Relative abundance of microbial taxa in mid-vaginal bacterial communities of “<i>Ca.</i> M. girerdii” positive women is shown. The dendrogram was generated using Ward’s method with Manhattan distance. This analysis includes only mid-vaginal samples that exhibited at least 0.1% “<i>Ca</i>. M. girerdii” by 16S rDNA profiling. Clinical diagnosis is indicated in the first bar, and presence of <i>T. vaginalis</i> by RT-PCR is indicated in the second bar (orange designates a negative result and pink designates a positive result). The three samples dominated by <i>L. crispatus</i> and the three samples with the highest prevalence of <i>L. iners</i> were negative for <i>T. vaginalis</i>.</p
Phylogenetic tree of 16SrRNA shows uncultured “<i>Ca.</i> M. girerdii” clusters most closely with other uncultivated organisms in the Pneumoniae Group.
No full text<p>The maximum likelihood tree was inferred by RAxML 7.2.7 using the gamma-distributed heterogeneity rate categories with 1,000 bootstraps. The 16S rRNA gene alignments were manually inspected. The Hominis Group is shaded in blue, the Pneumoniae Group in green, the Hemoplasma Group in gray and the Spiroplasma Group in purple. The 16S rRNA sequence of “<i>Ca</i>. M. girerdii” VCU_M1, “<i>Ca</i>. M. girerdii” VCU_PA1, “<i>Ca</i>. M. girerdii” VCU JB1 and “<i>Ca</i>. M. girerdii” VCU_G1 were identical. “<i>Ca</i>. M. girerdii” groups most closely with “Mnola”, which shows 100% identity in 16S rRNA sequence, uncultivated organisms from the oral sample of a low birth weight infant (HG764209, HG764210, and HG764212) and uncultivated species from rumen and termite gut in the Pneumoniae Group. A partial 16S rRNA sequence from the vaginal sample of a woman who delivered full term (JX871253) also exhibits 99% identity with “<i>Ca</i>. M. girerdii”, but was not included in the analysis due to its length.</p
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