Candida guilliermondii: biotechnological applications, perspectives for biological control, emerging clinical importance and recent advances in genetics

Candida guilliermondii (teleomorph Meyerozyma guilliermondii) is an ascomycetous species belonging to the Saccharomycotina CTG clade which has been studied over the last 40 years due to its biotechnological interest, biological control potential and clinical importance. Such a wide range of applications in various areas of fundamental and applied scientific research has progressively made C. guilliermondii an attractive model for exploring the potential of yeast metabolic engineering as well as for elucidating new molecular events supporting pathogenicity and antifungal resistance. All these research fields now take advantage of the establishment of a useful molecular toolbox specifically dedicated to C. guilliermondii genetics including the construction of recipient strains, the development of selectable markers and reporter genes and optimization of transformation protocols. This area of study is further supported by the availability of the complete genome sequence of the reference strain ATCC 6260 and the creation of numerous databases dedicated to gene ontology annotation (metabolic pathways, virulence, and morphogenesis). These genetic tools and genomic resources represent essential prerequisites for further successful development of C. guilliermondii research in medical mycology and in biological control by facilitating the identification of the multiple factors that contribute to its pathogenic potential. These genetic and genomic advances should also expedite future practical uses of C. guilliermondii strains of biotechnological interest by opening a window into a better understanding of the biosynthetic pathways of valuable metabolites.     

Sleep deprivation affects the sensitivity of proactive and reactive action monitoring: A behavioural and ERP analysis

We studied the impact of sleep deprivation on action monitoring. Each participant performed a Simon task after a normal night of sleep and after 26 h of awakening. Reaction time (RT) distributions were analyzed and the sensitivity of the error negativity (Ne/Ne like) to response correctness was examined.     

COVID-19 or not COVID-19? Compared characteristics of patients hospitalized for suspected COVID-19

European Journal of Clinical Microbiology & Infectious Diseases - During an epidemic period, we compared patients hospitalized for initial suspicion of COVID-19 but for whom an alternative...     

Longitudinal Analysis of Inflammatory Response to SARS-CoV-2 in the Upper Respiratory Tract Reveals an Association with Viral Load,Independent of Symptoms

Background

SARS-CoV-2 infection leads to high viral loads in the upper respiratory tract that may be determinant in virus dissemination. The extent of intranasal antiviral response in relation to symptoms is unknown. Understanding how local innate responses control virus is key in the development of therapeutic approaches.

Methods

SARS-CoV-2-infected patients were enrolled in an observational study conducted at the Geneva University Hospitals, Switzerland, investigating virological and immunological characteristics. Nasal wash and serum specimens from a subset of patients were collected to measure viral load, IgA specific for the S1 domain of the spike protein, and a cytokine panel at different time points after infection; cytokine levels were analyzed in relation to symptoms.

Results

Samples from 13 SARS-CoV-2-infected patients and six controls were analyzed. We found an increase in CXCL10 and IL-6, whose levels remained elevated for up to 3 weeks after symptom onset. SARS-CoV-2 infection also induced CCL2 and GM-CSF, suggesting local recruitment and activation of myeloid cells. Local cytokine levels correlated with viral load but not with serum cytokine levels, nor with specific symptoms, including anosmia. Some patients had S1-specific IgA in the nasal cavity while almost none had IgG.

Conclusion

The nasal epithelium is an active site of cytokine response against SARS-CoV-2 that can last more than 2 weeks; in this mild COVID-19 cohort, anosmia was not associated with increases in any locally produced cytokines.

     

Transforaminal and systemic diffusion of an active agent from a zinc oxide eugenol-based endodontic sealer containing hydrocortisone—in an in vivo model

Objectives

This study aimed to quantify in vivo the release of hydrocortisone acetate (HCA) contained in a zinc oxide eugenol-based endodontic sealer, in various tissues.

Materials and methods

Roots of human teeth, shaped with One Shape single file and sealed with Endomethasone N, previously radiolabelled with tritium (³H-HCA), were implanted in the back of 24 mice. Mice were sacrificed at 2, 8, 24, and 48 h to evaluate and quantify the amount of radioactivity in subcutaneous tissues surrounding the apex (periapical-like) of the implanted teeth, blood, spleen, kidneys, liver, and urine.

Results

Radioactivity was released from the apex of the tooth into the periapical-like tissues with a peak measured at 2 h post-implantation (2.25% of the initial radioactivity/g). This quantity decreased significantly over time between 2 h and each time points. Radioactivity was still measured up to 48 h in the periapical-like tissues (0.42% of the initial radioactivity). The same pattern of kinetic was observed for all organs. The total quantity of radioactivity significantly decreased over time from 4.36% measured 2 h post-implantation to 0.74% at 48 h. Finally, about 10% of the initial radioactivity from Endomethasone N used to fill the root canal was retrieved after 48 h in the urine.

Conclusions

This study demonstrated that radioactive-HCA from Endomethasone N can diffuse through the apex of the root canal and follow a classical pharmacokinetics.

Clinical relevance

This mouse model shows that radioactive-HCA can diffuse through the apex and do not accumulate in periapical-like tissues and organs.