Wild ciliates differ in susceptibility to Legionella pneumophila JR32

We investigated how Legionella pneumophila (Lp) JR32 interacts with Anteglaucoma CS11A and Colpoda E6, two ciliates that we isolated from sewage and sink trap sludge, respectively, using a handmade maze device containing a 96-well crafting plate. Our 185 rDNA-based phylogenetic analysis showed that Anteglaucoma CS11A and Colpoda E6 formed distinct clades. Scanning electron microscopy showed that Anteglaucoma CS11A had a bigger-sized body than Colpoda E6 and, unlike Tetrahymena IB (the reference strain), neither ciliate produced pellets, which are extracellular vacuoles. Fluorescence microscopic observations revealed that although the intake amounts differed, all three ciliates rapidly ingested LpJR32 regardless of the presence or absence of the icm/dot virulence genes, indicating that they all interacted with LpJR32. In co-cultures with Anteglaucoma CS11A, the LpJR32 levels were maintained but fell dramatically when the co-culture contained the LpJR32 icm/dot deletion mutant instead. Anteglaucoma CS11 A died within 2days of co-culture with LpJR32, but survived co-culture with the deletion mutant. In co-cultures with Colpoda E6, LpJR32 levels were maintained but temporarily decreased independently of the virulence gene. Concurrently, the Colpoda E6 ciliates survived by forming cysts, which may enable them to resist harsh environments, and by diminishing the sensitivity of trophozoites to Lp. In the Tetrahymena IB co-cultures with LpJR32 or Delta icm/dot, the Lp levels were maintained, albeit with temporal decreases, and the Tetrahymena IB levels were also maintained. We conclude that unlike Tetrahymena IB with pellet production, Anteglaucoma CS11A can be killed by LpJR32 infection, and Colpoda E6 can resist LpJR32 infection through cyst formation and the low sensitivity of trophozoites to Lp. Thus, the two ciliates that we isolated had different susceptibilities to LpJR32 infection

Usefulness of a 3D-printing air sampler for capturing live airborne bacteria and exploring the environmental factors that can influence bacterial dynamics

We created a handmade 3D-printed air sampler to effectively collect live airborne bacteria, and determined which environmental factors influenced the bacteria. Bacterial colony forming units (CFUs) in the air samples (n = 37) were monitored by recording the environmental changes occurring over time, then determining the presence/absence of correlations among such changes. The bacterial CFUs changed sharply and were significantly correlated with the DNA concentrations, indicating that the captured bacteria made up most of the airborne bacteria. Spearman's rank correlation analysis revealed significant correlations between the bacterial CFU values and some environmental factors (humidity, wind speed, insolation, and 24-h rainfall). Similarly the significant associations of CFU with humidity and wind speed were also found by multiple regression analysis with box-cox transformation. Among our panel of airborne bacteria (952 strains), 70 strains were identified as soil-derived Bacillus via the production of Escherichia coli- and Staphylococcus aureus-growth inhibiting antibiotics and by 16S rDNA typing. Soil-derived protozoa were also isolated from the air samples. We conclude that the airborne bacteria mainly derived from soil can alter in number according to environmental changes. Our sampler, which was created by easy-to-customize 3D printing, is a useful device for understanding the dynamics of live airborne bacteria. (C) 2021 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved

Resveratrol enhances the clearance of mitochondrial damage by vitrification and improves the development of vitrified-warmed bovine embryos.

The present study investigated the vitrification-induced deterioration of mitochondrial functions that may reduce the developmental ability of post-warming bovine embryos. In addition, the effect of supplementation of the culture medium with resveratrol on the mitochondrial functions and post-warming embryonic development was examined. Two days after in vitro fertilization, embryos with 8-12 cells (referred to hereafter as 8-cell embryos) were vitrified and warmed, followed by in vitro incubation for 5 days in a culture medium containing either the vehicle or 0.5 μM resveratrol. Vitrification reduced embryonic development until the blastocyst stage, reduced the ATP content of embryos, and impaired the mitochondrial genome integrity, as determined by real-time polymerase chain reaction. Although the total cell number and mitochondrial DNA copy number (Mt-number) of blastocysts were low in the vitrified embryos, the Mt-number per blastomere was similar among the blastocysts derived from fresh (non-vitrified) and vitrified-warmed embryos. Supplementation of the culture medium with resveratrol enhanced the post-warming embryonic development and reduced the Mt-number and reactive oxygen species level in blastocysts and blastomeres without affecting the ATP content. An increase in the content of cell-free mitochondrial DNA in the spent culture medium was observed following cultivation of embryos with resveratrol. These results suggested that vitrification induces mitochondrial damages and that resveratrol may enhance the development of post-warming embryos and activates the degeneration of damaged mitochondria, as indicated by the increase in the cell-free mitochondrial DNA content in the spent culture medium and the decrease in the Mt-number of blastocysts and blastomeres

The effect of Katsura-uri (Japanese pickling melon, Cucumis melo var. conomon) and its derived ingredient methylthioacetic acid on energy metabolism during aerobic exercise

[Purpose] We investigated the effect of Katsura-uri (Japanese pickling melon; Cucumis melo var. conomon) on energy metabolism during exercise in human and animal studies. Methods Eight healthy men (mean age, 21.4 ± 0.7 years) participated in a single-blind, crossover study. Thirty minutes after ingesting the Katsura-uri drink or placebo drink, they exercised on a cycle ergometer at 40% maximal heart rate for 30 min. Respiratory gas analysis was performed during exercise to examine oxygen consumption and substrate utilization. Blood biochemical parameters were evaluated during exercise. In the animal study, the effect of methylthioacetic acid (MTA), a Katsura-uri derived component was examined in mice. Immediately after running at 25 m/min for 30 min, biochemical parameters in the hind limb muscle and blood of mice were measured. [Results] Oxygen consumption during exercise was higher in the Katsura-uri condition (19.8 ± 3.5 mL/kg/min) than the placebo condition (18.6 ± 3.0 mL/kg/min) (P < 0.05). The elevation of blood lactate was lower in the Katsura-uri condition (1.7 ± 0.4 mM) than the placebo condition (2.2 ± 0.6 mM) 15 min after beginning exercise (P < 0.05). There was a higher positive correlation between lactate concentration and carbohydrate oxidation during exercise in the Katsura-uri condition (R2 = 0.86) compared to the placebo condition (R2 = 0.47). The decrease in intermuscular pH and the increase in blood lactate following exercise were prevented by MTA supplementation (250 ppm) with significant differences in the MTA-supplemented group compared to the control group. [Conclusions] These results suggest that the ingestion of Katsura-uri and/or MTA improves glucose metabolism and acidification in skeletal muscles during exercise in human and animal studies

7-Phenylheptanoic Acid-Hydroxypropyl β-Cyclodextrin Complex Slows the Progression of Renal Failure in Adenine-Induced Chronic Kidney Disease Mice

The characteristic accumulation of circulating uremic toxins, such as indoxyl sulfate (IS), in chronic kidney disease (CKD) further exacerbates the disease progression. The gut microbiota, particularly gut bacterial-specific enzymes, represents a selective and attractive target for suppressing uremic toxin production and slowing the progression of renal failure. This study investigates the role of 4-phenylbutyrate (PB) and structurally related compounds, which are speculated to possess renoprotective properties in suppressing IS production and slowing or reversing renal failure in CKD. In vitro enzyme kinetic studies showed that 7-phenylheptanoic acid (PH), a PB homologue, suppresses the tryptophan indole lyase (TIL)-catalyzed decomposition of tryptophan to indole, the precursor of IS. A hydroxypropyl β-cyclodextrin (HPβCD) inclusion complex formulation of PH was prepared to enhance its biopharmaceutical properties and to facilitate in vivo evaluation. Prophylactic oral administration of the PH-HPβCD complex formulation reduced circulating IS and attenuated the deterioration of renal function and tubulointerstitial fibrosis in adenine-induced CKD mice. Additionally, treatment of moderately advanced adenine-induced CKD mice with the formulation ameliorated renal failure, although tissue fibrosis was not improved. These findings suggest that PH-HPβCD can slow the progression of renal failure and may have implications for preventing or managing CKD, particularly in early-stage disease