scholarly journals Opportunistic gill infection is associated with TiO2 nanoparticle-induced mortality in zebrafish

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0247859
Author(s):  
Chiao-Yi Huang ◽  
Wei-Sheng Yu ◽  
Geng-Chia Liu ◽  
Shih-Che Hung ◽  
Jen-Hsiang Chang ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Titanium Dioxide Nanoparticles ◽  
Bacterial Load ◽  
Life Forms ◽  
Inert Material ◽  
Zebrafish Model ◽  
Aquatic Life ◽  
Dorsal Fin ◽  
Low Toxicity ◽  
Total Bacteria

The large amounts of engineered titanium dioxide nanoparticles (TiO2NPs) that have been manufactured have inevitably been released into the ecosystem. Reports have suggested that TiO2 is a relatively inert material that has low toxicity to animals. However, as various types of NPs increasingly accumulate in the ocean, their effects on aquatic life-forms remain unclear. In this study, a zebrafish model was used to investigate TiO2NP-induced injury and mortality. We found that the treatment dosages of TiO2NP are positively associated with increased motility of zebrafish and the bacterial counts in the water. Notably, gill but not dorsal fin and caudal fin of the zebrafish displayed considerably increased bacterial load. Metagenomic analysis further revealed that gut microflora, such as phyla Proteobacteria, Bacteroidetes, and Actinobacteria, involving more than 95% of total bacteria counts in the NP-injured zebrafish gill samples. These results collectively suggest that opportunistic bacterial infections are associated with TiO2NP-induced mortality in zebrafish. Infections secondary to TiO2NP-induced injury could be a neglected factor determining the detrimental effects of TiO2NPs on wild fish.

Marine Bizarrerie: The Imaginative Biology of the Underwater Frontier

2018 ◽  
pp. 169-185
Author(s):  
Margaret Cohen
Keyword(s):  
Nineteenth Century ◽  
Natural Science ◽  
Gustave Flaubert ◽  
Life Forms ◽  
Life Cycles ◽  
Victor Hugo ◽  
Aquatic Life ◽  
Psychological Experience ◽  
Narrative Prose ◽  
Jules Michelet

The great variety and radical metamorphoses of aquatic life forms attracted huge fascination during the nineteenth century, in part because they defied familiar paradigms of development and progress. In this chapter, Cohen explores how writers were inspired by such marine life-cycles to try out experiments in narrative prose, focusing in particular on the influence of marine variety on the depiction of psychological experience. Starting with Charles Kingsley’s Glaucus (1855), Cohen argues that Kingsley uses the life forms of the underwater kingdom to re-energise the poetic figure of metamorphosis, which, in his treatment, depends more upon natural science than myth. Cohen then shows how Kingsley translates marine metamorphosis into narrative experiment in The Water-Babies (1862), and creates an account of psychological experience that is more hallucinatory and phantasmagorical than developmental. Cohen finally suggests that marine metamorphosis has a similar impact on other authors, including Gustave Flaubert, Victor Hugo and Jules Michelet, all of whom stress the disturbing and disruptive possibilities of a psychological prose inspired by aquatic biology.

scholarly journals Rapid preparation of terbium-doped titanium dioxide nanoparticles and their enhanced photocatalytic performance

2019 ◽  
Vol 6 (10) ◽  
pp. 191077 ◽  
Author(s):  
Zhencui Wang ◽  
Yuechao Song ◽  
Xingfei Cai ◽  
Jun Zhang ◽  
Tianle Tang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Titanium Dioxide Nanoparticles ◽  
Earth Metal ◽  
Nitrate Hexahydrate ◽  
Doping Amount ◽  
X Ray ◽  
Low Toxicity

Further applications of photocatalysis were limited by the high recombination probability of photo-induced electron–hole pairs in traditional titanium dioxide nanoparticles (TiO 2 NPs). Herein, we modified them with rare earth metal via a facile sol–gel method, using tetrabutyl titanate as a precursor and terbium (III) nitrate hexahydrate as terbium (Tb) source. The resulting samples with different Tb doping amounts (from 0 to 2%) have been characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photo-electron spectroscopy and a scanning electron microscope. The photocatalytic performance of Tb-doped TiO 2 was evaluated by the degradation of methylene blue. The effects of Tb doping amount and initial pH value of solution were investigated in detail. The composite with Tb doping amount of 1.0 wt% showed the highest photocatalytic performance. It exhibited approximately three times enhancement in photocatalytic activity with a reaction rate constant of 0.2314 h −1 when compared with that of commercial P25 (0.0827 h −1 ). In addition, it presented low toxicity on zebrafishes with 96 h-LC 50 of 23.2 mg l −1 , and has been proved to be reusable for at least four cycles without significant loss of photocatalytic activity. A probable photocatalytic mechanism of Tb-doped TiO 2 was proposed according to the active species trapping experiments. The high photocatalytic performance, excellent reusability and low toxicity of Tb-doped TiO 2 indicated that it is a promising candidate material in the future treatment of dye wastewater.

scholarly journals Anti-quorum Sensing and Protective Efficacies of Naringin Against Aeromonas hydrophila Infection in Danio rerio

2020 ◽  
Vol 11 ◽  
Author(s):  
Ramanathan Srinivasan ◽  
Kannan Rama Devi ◽  
Sivasubramanian Santhakumari ◽  
Arunachalam Kannappan ◽  
Xiaomeng Chen ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Bacterial Load ◽  
Antibiotic Resistance Genes ◽  
Alternative Methods ◽  
Zebrafish Model ◽  
Virulence Gene Expression

It is now well known that the quorum sensing (QS) mechanism coordinates the production of several virulence factors and biofilm formation in most pathogenic microorganisms. Aeromonas hydrophila is a prime pathogen responsible for frequent outbreaks in aquaculture settings. Recent studies have also continuously reported that A. hydrophila regulates virulence factor production and biofilm formation through the QS system. In addition to the presence of antibiotic resistance genes, biofilm-mediated antibiotic resistance increases the severity of A. hydrophila infections. To control the bacterial pathogenesis and subsequent infections, targeting the QS mechanism has become one of the best alternative methods. Though very few compounds were identified as QS inhibitors against A. hydrophila, to date, the screening and identification of new and effective natural QS inhibitors is a dire necessity to control the infectious A. hydrophila. The present study endorses naringin (NA) as an anti-QS and anti-infective agent against A. hydrophila. Initially, the NA showed a concentration-dependent biofilm reduction against A. hydrophila. Furthermore, the results of microscopic analyses and quantitative virulence assays displayed the promise of NA as a potential anti-QS agent. Subsequently, the downregulation of ahh1, aerA, lip and ahyB validate the interference of NA in virulence gene expression. Furthermore, the in vivo assays were carried out in zebrafish model system to evaluate the anti-infective potential of NA. The outcome of the immersion challenge assay showed that the recovery rate of the zebrafish has substantially increased upon treatment with NA. Furthermore, the quantification of the bacterial load upon NA treatment showed a decreased level of bacterial counts in zebrafish when compared to the untreated control. Moreover, the NA treatment averts the pathogen-induced histoarchitecture damages in vital organs of zebrafish, compared to their respective controls. The current study has thus analyzed the anti-QS and anti-infective capabilities of NA and could be employed to formulate effective treatment measures against A. hydrophila infections.

Culture-Independent Evaluation of Bacterial Contamination Patterns on Pig Carcasses at a Commercial Slaughter Facility

2019 ◽  
Vol 82 (10) ◽  
pp. 1677-1682 ◽  
Author(s):  
BENJAMIN ZWIRZITZ ◽  
STEFANIE U. WETZELS ◽  
ISABEL RABANSER ◽  
SARAH THALGUTER ◽  
MONIKA DZIECIOL ◽  
...  
Keyword(s):  
Bacterial Cell ◽  
Bacterial Load ◽  
Control Point ◽  
Fold Change ◽  
Critical Control Point ◽  
Meat Spoilage ◽  
Pseudomonas Species ◽  
Pig Carcasses ◽  
Water Amount ◽  
Total Bacteria

ABSTRACT Traditionally, the microbiological status of meat is determined by culture-based techniques, although many bacteria are not able to grow on conventional media. The aim of this study was to obtain quantitative data on total bacterial cell equivalents, as well as taxa-specific abundances, on carcass surfaces during pig slaughter using quantitative real-time PCR. We evaluated microbial contamination patterns of total bacteria, Campylobacter, Escherichia coli, Lactobacillus group, Listeria monocytogenes, Salmonella, and Pseudomonas species throughout slaughtering and on different carcass areas. In addition, we compared contamination levels of breeding sow carcasses with fattening pig carcasses, and we assessed the efficacy of carcass polishing machines under two water amount conditions. Our results demonstrate that relevant meat-spoilage organisms show similar contamination patterns to total bacteria. The highest bacterial load was detected in the stunning chute (4.08 × 105 bacterial cell equivalents per cm2) but was reduced by 3 log levels after singeing and polishing (P < 0.001). It increased again significantly by a 4.73-fold change until the classification step. Levels of Campylobacter, Lactobacillus, and Pseudomonas species and of E. coli followed a similar trend but varied between 0 and 2.49 × 104 bacterial cell equivalents per cm2. Microbial levels did not vary significantly between sampled carcass areas for any analyzed taxa. Running the polishing machine with a low water amount proved to be less prone to microbial recontamination compared with a high water amount (17.07-fold change, P = 0.024). In the studied slaughterhouse, slaughter of breeding sows did not produce microbiologically safe meat products (>104 cells per cm2) and the implementation of specific hazard analysis critical control point systems for the slaughter of breeding sows should be considered. A larger cohort from different abattoirs is needed to confirm our results and determine whether this is universally valid.

scholarly journals Assessment of Respiratory Bacterial Coinfections Among Severe Acute Respiratory Syndrome Coronavirus 2-Positive Patients Hospitalized in Intensive Care Units Using Conventional Culture and BioFire, FilmArray Pneumonia Panel Plus Assay

2020 ◽  
Vol 7 (11) ◽  
Author(s):  
Camille Kolenda ◽  
Anne-Gaëlle Ranc ◽  
Sandrine Boisset ◽  
Yvan Caspar ◽  
Anne Carricajo ◽  
...  
Keyword(s):  
Intensive Care ◽  
Severe Acute Respiratory Syndrome ◽  
Intensive Care Units ◽  
Bacterial Infections ◽  
Early Stage ◽  
Bacterial Load ◽  
Empiric Antibiotic Therapy ◽  
Molecular Diagnostic ◽  
Oral Flora ◽  
Conventional Culture

Abstract Background Approximately 15% of patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) present with severe forms of the disease and require hospitalization in intensive care units, which has been associated with high mortality rates. The prevalence of bacterial infections in these patients is not well established, and more data are needed to guide empiric antibiotic therapy and improve patient outcomes. Methods In this prospective multicenter study, we assessed bacterial coinfections identified in culture from 99 French patients infected by SARS-Cov-2 and hospitalized in intensive care units. We concomitantly evaluated an innovative molecular diagnostic technology technique, the BioFire, FilmArray Pneumonia Panel plus (FA-pneumo) assay, to identify these coinfections at an early stage, and its concordance with conventional culture. Results We showed that a bacterial coinfection was detected in 15% of patients based on conventional culture. Staphylococcus aureus and Haemophilus influenzae were the most prevalent pathogens. The sensitivity of FA-pneumo compared with culture was 100%. In contrast, the specificity varied between 88.4% and 100% according to the pathogen, and our results highlighted that 60.5% of bacterial targets reported using this assay were not recovered by culture; 76.9% of discordant results corresponded to bacteria belonging to commensal oral flora and/or reported with ≤105 copies/mL bacterial nucleic acids. Conclusions Based on its excellent sensitivity, the FA-pneumo assay is useful to rule out bacterial coinfections in the context of severe SARS-CoV-2 infection and avoid the inappropriate prescription of antibiotics. However, positive tests should be interpreted carefully, taking into consideration deoxyribonucleic acid bacterial load and all clinical and biological signs.

scholarly journals Efficient 5-OP-RU-Induced Enrichment of Mucosa-Associated Invariant T Cells in the Murine Lung Does Not Enhance Control of Aerosol Mycobacterium tuberculosis Infection

2020 ◽  
Vol 89 (1) ◽  
pp. e00524-20 ◽  
Author(s):  
Charles Kyriakos Vorkas ◽  
Olivier Levy ◽  
Miroslav Skular ◽  
Kelin Li ◽  
Jeffrey Aubé ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Bacterial Infections ◽  
Cell Activation ◽  
Bacterial Load ◽  
Cell Subset ◽  
Mycobacterium Tuberculosis Infection ◽  
Class I Mhc ◽  
Content Type ◽  
Mait Cells ◽  
Mait Cell

ABSTRACTMucosa-associated invariant T (MAIT) cells are an innate-like T cell subset in mammals that recognize microbial vitamin B metabolites presented by the evolutionarily conserved major histocompatibility complex class I (MHC I)-related molecule, MR1. Emerging data suggest that MAIT cells may be an attractive target for vaccine-induced protection against bacterial infections because of their rapid cytotoxic responses at mucosal services to a widely conserved bacterial ligand. In this study, we tested whether a MAIT cell priming strategy could protect against aerosol Mycobacterium tuberculosis infection in mice. Intranasal costimulation with the lipopeptide Toll-like receptor (TLR)2/6 agonist, Pam2Cys (P2C), and the synthetic MR1 ligand, 5-OP-RU, resulted in robust expansion of MAIT cells in the lung. Although MAIT cell priming significantly enhanced MAIT cell activation and expansion early after M. tuberculosis challenge, these MAIT cells did not restrict M. tuberculosis bacterial load. MAIT cells were depleted by the onset of the adaptive immune response, with decreased detection of granzyme B+ and gamma interferon (IFN-γ)+ MAIT cells relative to that in uninfected P2C/5-OP-RU-treated mice. Decreasing the infectious inoculum, varying the time between priming and aerosol infection, and testing MAIT cell priming in nitric oxide synthase 2 (NOS2)-deficient mice all failed to reveal an effect of P2C/5-OP-RU-induced MAIT cells on M. tuberculosis control. We conclude that intranasal MAIT cell priming in mice induces early MAIT cell activation and expansion after M. tuberculosis exposure, without attenuating M. tuberculosis growth, suggesting that MAIT cell enrichment in the lung is not sufficient to control M. tuberculosis infection.

scholarly journals Febrile Core Temperature Is Essential for Optimal Host Defense in Bacterial Peritonitis

2000 ◽  
Vol 68 (3) ◽  
pp. 1265-1270 ◽  
Author(s):  
Qinqqi Jiang ◽  
Alan S. Cross ◽  
Ishwar S. Singh ◽  
T. Timothy Chen ◽  
Rose M. Viscardi ◽  
...  
Keyword(s):  
Core Temperature ◽  
Host Defense ◽  
Bacterial Infections ◽  
Bacterial Load ◽  
Cytokine Expression ◽  
Microbial Pathogens ◽  
Necrosis Factor Alpha ◽  
Bacterial Peritonitis ◽  
Tnf Α ◽  
Factor Alpha

ABSTRACT Fever, a nonspecific acute-phase response, has been associated with improved survival and shortened disease duration in infections, but the mechanisms of these beneficial responses are poorly understood. We previously reported that increasing core temperature of bacterial endotoxin (LPS)-challenged mice to the normal febrile range modified expression of tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and IL-6, three cytokines critical to mounting an initial defense against microbial pathogens, but survival was not improved in the warmer animals. We speculated that our inability to show a survival benefit of optimized cytokine expression in the warmer animals reflected our use of LPS, a nonreplicating agonist, rather than an infection with viable pathogens. The objective of this study was to determine if increasing murine core temperature altered cytokine expression and improved survival in an experimental bacterial peritonitis model. We showed that housing mice at 35.5°C rather than 23°C increased core temperature from 36.5 to 37.5°C to 39.2 to 39.7°C, suppressed plasma TNF-α expression for the initial 48 h, delayed gamma interferon expression, improved survival, and reduced the bacterial load in mice infected with Klebsiella pneumoniae peritonitis. We showed that the reduced bacterial load was not caused by a direct effect on bacterial proliferation and probably reflected enhanced host defense. These data suggest that the increase in core temperature that occurs during bacterial infections is essential for optimal antimicrobial host defense.

scholarly journals Dietary Polyunsaturated Fatty Acids Increase Survival and Decrease Bacterial Load during Septic Staphylococcus aureus Infection and Improve Neutrophil Function in Mice

2014 ◽  
Vol 83 (2) ◽  
pp. 514-521 ◽  
Author(s):  
Sara L. Svahn ◽  
Louise Grahnemo ◽  
Vilborg Pálsdóttir ◽  
Intawat Nookaew ◽  
Karl Wendt ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Bacterial Infections ◽  
Saturated Fatty Acids ◽  
Bacterial Load ◽  
Neutrophil Function ◽  
High Fat ◽  
Content Type

Severe infection, including sepsis, is an increasing clinical problem that causes prolonged morbidity and substantial mortality. At present, antibiotics are essentially the only pharmacological treatment for sepsis. The incidence of resistance to antibiotics is increasing; therefore, it is critical to find new therapies for sepsis.Staphylococcus aureusis a major cause of septic mortality. Neutrophils play an important role in the defense against bacterial infections. We have shown that a diet with high levels of dietary saturated fatty acids decreases survival in septic mice, but the mechanisms behind this remain elusive. The aim of the present study was to investigate how the differences in dietary fat composition affect survival and bacterial load after experimental septic infection and neutrophil function in uninfected mice. We found that, afterS. aureusinfection, mice fed a polyunsaturated high-fat diet (HFD-P) for 8 weeks had increased survival and decreased bacterial load during sepsis compared with mice fed a saturated high-fat diet (HFD-S), similar to mice fed a low-fat diet (LFD). Uninfected mice fed HFD-P had a higher frequency of neutrophils in bone marrow than mice fed HFD-S. In addition, mice fed HFD-P had a higher frequency of neutrophils recruited to the site of inflammation in response to peritoneal injection of thioglycolate than mice fed HFD-S. Differences between the proportion of dietary protein and carbohydrate did not affect septic survival at all. In conclusion, polyunsaturated dietary fat increased both survival and efficiency of bacterial clearance during septicS. aureusinfection. Moreover, this diet increased the frequency and chemotaxis of neutrophils, key components of the immune response toS. aureusinfections.

Early infection during burn-induced inflammatory response results in increased mortality and p38-mediated neutrophil dysfunction

2010 ◽  
Vol 299 (3) ◽  
pp. R918-R925 ◽  
Author(s):  
Samuel G. Adediran ◽  
Derrick J. Dauplaise ◽  
Kevin R. Kasten ◽  
Johannes Tschöp ◽  
Jonathan Dattilo ◽  
...  
Keyword(s):  
Oxidative Burst ◽  
Bacterial Infections ◽  
Burn Injury ◽  
Bacterial Load ◽  
Significant Difference ◽  
Scald Injury ◽  
Altered Immune Status ◽  
Direct Contrast ◽  
Intraperitoneal Infection ◽  
And Function

Following burn injury, the host is susceptible to bacterial infections normally cleared by healthy patients. We hypothesized that during the systemic immune response that follows scald injury, the host's altered immune status increases infection susceptibility. Using a murine model of scald injury under inhaled anesthesia followed by intraperitoneal infection, we observed increased neutrophil numbers and function at postburn day (PBD) 1 compared with sham-burned and PBD4 mice. Further, increased mortality, bacteremia, and serum IL-6 were observed in PBD1 mice after Pseudomonas aeruginosa (PA) infection compared with sham-burned and PBD4 mice infected with PA. To examine these disparate responses, we investigated neutrophils isolated at 5 and 24 h following PA infection from PBD1 and sham-burned mice. Five hours after infection, there was no significant difference in number of recruited neutrophils; however, neutrophils from injured mice had decreased activation, active-p38, and oxidative burst compared with sham-burned mice. In direct contrast, 24 h after infection, we observed increased numbers, active-p38, and oxidative burst of neutrophils from PBD1 mice. Finally, we demonstrated that in neutrophils isolated from PBD1 mice, the observed increase in oxidative burst was p38 dependent. Altogether, neutrophil activation and function from thermally injured mice are initially delayed and later exacerbated by a p38-dependent mechanism. This mechanism is likely key to the observed increase in bacterial load and mortality of PBD1 mice infected with PA.

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