bluuebunny/crossref_metadata_2025_split huggingface dataset:
S3.4e Unraveling the role of DOG genes in a novel alternative pathway of glycerol biosynthesis in Candida albicans and its influence on virulence
Authors: Awasthy Chinmayee , Van Genechten Wouter , Himmereich Uwe , Van Dijck Patrick 
Published: September 2022

Abstract

S3.4 Free oral paper session, September 21, 2022, 4:45 PM - 6:15 PM
DOG genes, encoding for 2-deoxyglucose-6-phosphate phosphatase are low molecular weight phosphatases, with an unknown biological function. In contrast to Saccharomyces cerevisiae which has two DOG homologs, C. albicans only has one DOG gene. We hypothesized that DOG1 plays an important role under osmotic or ionic stress by biosynthesizing glycerol, which is known to be vital for biofilm formation and virulence of this pathogenic yeast, via a novel alternative pathway.

The known classical pathway of glycerol production begins when the glycolytic intermediate molecule dihydroxyacetone phosphate (DHAP) is converted into glycerol-3-phosphate (G-3-P) by a pair of glycerol-3-phosphate-dehydrogenases, Gpd1 and Gpd2. G-3-P is further dephosphorylated into glycerol by glycerol-3-phosphate-phosphatases, Gpp1 and Gpp2. However, an alternative pathway, where DHAP is dephosphorylated into DHA, which is subsequently converted into glycerol has been proposed, but the enzymes involved in this process have not yet been described. We recently showed that in Saccharomyces cerevisiae, the DOG enzymes are involved in the production of DHA from DHAP, thereby allowing the synthesis of glycerol in the absence of the classical pathway. Overexpression of the DOG genes restored the osmo-tolerance of the gpp1Δ gpp2Δand gpd1Δ gpd2Δ double deletion strains. Furthermore, purified DOG enzymes could also convert DHAP into DHA (Awasthy et al., submitted).

Since DOG1 has a potential role in biosynthesizing glycerol via an unconventional route, we are interested to determine its contribution in influencing virulence and biofilm formation in Candida albicans. This putative pathway has been overlooked for the past two decades, leaving behind an evident knowledge gap. We have now generated multiple deletion strains, using CRISPR Cas9, for the C. albicans counterparts of the GPP, GPD, and DOG genes as well as multiple DOG1 overexpression strains in which we observed the restoration of osmotic stress tolerance phenotypically and via growth curves. We also have NMR data showing the accumulation of various metabolites of central metabolism in these strains. Additionally, we have determined the possible role of DOG1 on virulence factors like morphogenesis, adhesion, and biofilm formation in vitro as well as in vivo, the latter with our catheter-based biofilm subcutaneous mouse model system. We also linked DOG1 and its role in glycerol biosynthesis to the survival of C. albicans inside macrophages. Finally, we would be setting up a high throughput small compound screening for this phosphatase as a potential antifungal drug target.
S4.3b Candida glabrata-host interactions
Authors: Hube Bernhard 
Published: September 2022

Abstract

S4.3 Emergent species of the Candida genus, September 22, 2022, 10:30 AM - 12:00 PM
Candida glabrata is among the most common pathogenic yeasts of humans. Yet, this fungus is phylogenetically, genetically, and phenotypically very different from other clinically relevant Candida species. This includes an unusual high level of intrinsic resistance to antifungals such as azoles. Furthermore, in contrast to the rather aggressive pathogenicity mechanisms of the dominant Candida species, C. albicans, C. glabrata seems to have evolved strategies that are based on stealth, evasion and persistence, without causing severe host cell damage during infection. For example, C. glabrata is unable to invade epithelial cells in vitro and causes only low levels of damage in standard in vitro infection models. However, the addition of a single common host protein, albumin, strongly enhances the damage potential to vaginal epithelial cells.

Similar to other Candida species, the potential of C. glabrata to survive in human blood is low. However, C. glabrata can survive within macrophages for long periods without causing host cell damage and responses. This intracellular stage requires the acquisition of nutrients, such as biotin, facilitated by defined biotin up-take systems. Survival in macrophages is further supported by transient mitochondria dysfunction: C. glabrata is able to switch into a petite phenotype upon interaction with human phagocytes. The petite phenotype significantly differs from non-petite cells in its growth behavior, its interactions with the immune system, and even its resistance to antifungal drugs. Effectively, the interaction with phagocytes can render C. glabrata mostly resistant to commonly used azole drugs, and vice versa (‘cross resistance’), providing a principle mechanism by which intrinsic antifungal resistance may have evolved.

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S4.5d Comparing the diagnostic performance of the commonly used eumycetoma diagnostic tests using sequencing of the internally transcribed spacer region as the gold standard
Authors: Siddig Emmanuel , Nyuykonge Bertrand , Mhmoud Najwa , Abdallah Omnia , Bahar Mustafa , Ahmed Eiman , Nyaoke Borna , Zijlstra Ed , Verbon Annelies , Bakhiet Sahar , Fahal Ahmed , van de Sande Wendy 
Published: September 2022

Abstract

S4.5 Mycetoma Clinical Trial on fosravuconazole treatment in eumycetoma– Top Line Results, September 22, 2022, 10:30 AM - 12:00 PM

Objectives
Mycetoma is a neglected tropical implantation disease caused by 70 different infectious agents. Identifying the causative organism to the species level is essential for appropriate patient management. Ultrasound, histopathology, culture, and two species-specific PCRs are most the commonly used methods for species identification in endemic regions. The aim of this study was to compare the diagnostic performance of these commonly used assays using sequencing of barcoding genes as the gold standard.

Methods
This descriptive cross-sectional study was conducted at the Mycetoma Research Centre, University of Khartoum, Sudan. It included 222 patients suspected of fungal mycetoma caused by Madurella mycetomatis.

Results
In total 154 (69.3%) were correctly identified by ultrasound, histology, culture, and both species-specific PCRs. In 60 patients, at least one of the diagnostic tests failed to identify M. mycetomatis. A total of five patients had no evidence of eumycetoma, and for three, only the ultrasound was indicative of mycetoma. The two species-specific PCRs were the most sensitive and specific methods, followed by culture and histology. Ultrasound was the least specific as it only allowed differentiation between actinomycetoma and eumycetoma. The time to result was 9.38 minutes for ultrasound, 3.76 h for PCR, 8.5 days for histopathology, and 21 days for grain culturing.

Conclusion
Currently, PCR directly on DNA isolated from grains is the most rapid and reliable diagnostic tool to identify M. mycetomatis eumycetoma.
S5.3a Unraveling the genetic determinants of virulence in Cryptococcus neoformans
Authors: Jackson Katrina , Kisakye Diana , Macchietto Marissa , Tiffen Peter , Nielsen Kirsten 
Published: September 2022

Abstract

S5.3 Cellular pleomorphism and fungal virulence, September 22, 2022, 3:00 PM - 4:30 PM

Cryptococcus neoformans is a human pathogenic basidiomycete yeast that can cause cryptococcal meningitis (CM), predominantly in immunocompromised individuals. The patient outcome depends on both host and pathogen-specific factors, including C. neoformans genetics. A groundbreaking 2012 study was the first to show that patient outcome is associated with genetic differences between C. neoformans isolates. Subsequent population-wide sequencing studies have revealed over 100 sequence types (ST) of C. neoformans that are associated with both geographic location and clinical outcome. All these studies have been broad, examining the severity of disease cryptococcal phenotypes in a collection of highly diverse strains. We chose a narrow focus and collected various genotypic and phenotypic data from a single ST: ST93. ST93 is a common sequence type isolated from patients globally and is the most common clinical isolate found in the sub-Saharan African country of Uganda. Previously, we performed whole genome sequencing on 38 ST93 Ugandan clinical isolates. We identified 652 unique SNPs in this ST93 population compared to the H99 reference genome. We also showed that ST93 contained two subpopulations: ST9A and ST93B. In the current study, we further characterized the genotypic, phenotypic, and virulence differences between these 38 clinical isolates. Using Illumina sequence data, we identified a pattern of linkage disequilibrium that suggested that ST93A and ST93B are evolving separately. We performed long-read sequencing on each isolate to investigate chromosomal changes and large structural variations, allowing us to identify a chromosomal translocation event wherein parts of chromosome 11 had recombined with chromosome 3. Additionally, we characterized several in vitro phenotypes for each isolate and identified three distinct phenotypic clusters based on cell wall challenge and growth experiments. Next, we infected mice with 35 isolates and observed eight different disease manifestations, including isolates that caused non-CNS infections. Overall, by working within a single sequence type, we can gain a deeper understanding of how some small genetic changes can impact strain-specific phenotypes while others have no discernable effect. Eventually, these data can be used to provide valuable information about how each clinical isolate impacts patient outcomes.
S6.2b In vitro susceptibility testing of dermatophytes: toward standardization
Authors: Marie Ditte , Saunte Lindhardt 
Published: September 2022

Abstract

S6.2 Resurgence of dermatophytic infections, September 22, 2022, 4:45 PM - 6:15 PM
Antifungal treatment-resistant dermatophytosis has been known for years1. It has mainly been reported as sporadic cases with clinical failure to a specific antifungal confirmed by in vitro resistance to antifungal compounds determined by antifungal susceptibility testing (AFST). However, in vivo AFST of dermatophytes is not routinely available in most countries, and, therefore, many clinicians solve the problem by changing the antifungal treatment to another drug class hoping that it will result in clinical response. Unfortunately, cross-resistance revealing concomitantly reduced sensitivity to different classes of drugs including terbinafine and azoles have been reported2,3. Furthermore, an increase of antifungal resistant dermatophytosis has been noted mainly in India and other Asian countries4 but sporadic cases have also been registered in the Middle East, Europe, and North and South America suggesting that this may be the top of the iceberg5-8. This stress the need for a standardized AFST, which can be used routinely in order to surveil the disease spread and implement targeted antifungal treatment.

Molecular-based methods are able to detect a genetic mutation known to cause antifungal resistance (e.g., mutation in the squalene epoxidase gene)2 whereas culture-based AFST methods are able to determine the minimum inhibitory concentration (MIC) of a given drug for a specific clinical isolate. This should ideally enable to classify the isolate as sensitive, intermediate, or resistant to a specific antifungal agent, but unfortunately, it may be difficult to compare results across studies as the interpretations of MIC results are depending on the AFST method used. Following AFST methods have been used to determine the MIC of dermatophytes: E-test, agar dilution, agar disc diffusion, and macro- and microbroth dilution methods9. They differ in several ways including inoculum concentration, incubation temperature, incubation time, different culture media, and end-point criterion of fungal growth (percentage of growth inhibition)9,10. Standardization is therefore important, and currently, two standardized guidelines for in vitro AFST of dermatophytes exist. One is from the European Committee on Antimicrobial Susceptibility Testing (EUCAST)11 and the other is from the Clinical Laboratory Standards Institute (CLSI)12. Both are using microtiter plates and the EUCAST (E.Def 11.0) guideline has included MIC breakpoints for the classification of whether an isolate is susceptible or resistant to a given drug. Unfortunately, breakpoints are only available for a limited number of dermatophytes and antifungals11.

Standardized validated AFST methods will enable us to target the antifungal treatment thereby reducing the risk of ineffective and unnecessary exposure to inappropriate antifungals with potential side effects and reducing the risk of disease spreading.

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S7.3d Environmental surveillance of Aspergillus fumigatus in Dutch agricultural crops
Authors: Zhang Jianhua , de Rooij Bram , leendertse Peter , Zwaan Bas , Schoustra Sijmen 
Published: September 2022

Abstract

S7.3 Emergent theories on pathogenic fungal dispersal around the globe, September 23, 2022, 10:30 AM - 12:00 PM

Objectives
Azole-resistant Aspergillus fumigatus isolates from the environment hamper the treatment of patients suffering from Aspergillus diseases due to cross-resistance with agricultural azoles. Previous work has suggested A. fumigatus likely gains resistance through environmental azole exposure in so-called hotspots.

Methods
We investigated A. fumigatus resistance at multi-environmental sites including the compost, strawberry, and potatoes, where farmers used azole fungicides for crop protection.

Results
On average 105 A. fumigatus CFU/g was recovered of which roughly half were itraconazole and tebuconazole resistant. Similar tandem repeat-mediated resistance mechanisms were found in colonies cultured from these environmental sites as reported in clinical azole-resistant isolates.

Conclusions
Our results suggest that not only azole-containing plant-waste material but also other agricultural crops can be hotspots for resistance selection in A. fumigatus and underscores the need to further investigate transmission routes.
S8.3d Characterization of glycosylphosphatidylinositol-linked aspartyl proteases in Candida glabrata: Role in pathogenicity
Authors: Kaur Rupinder 
Published: September 2022

Abstract

S8.3 How the Fungal Cell Wall Glycan Can Modulate the Immune Response?, September 23, 2022, 3:00 PM - 4:30 PM

Candida glabrata is the second to fourth most common yeast pathogen found in Candida bloodstream infections, depending upon the geographical location. C. glabrata, which belongs to the Nakaseomyces clade, possesses a distinct set of virulence attributes which include the ability to survive and proliferate in macrophages, adhere to biotic and abiotic surfaces and survive a wide range of stresses. Our research is focused on unveiling the strategies that C. glabrata employs to survive the nutrient-poor hostile host environment and evade host immune response. Toward this end, we are delineating the cellular processes, that are regulated by the family of 11 putative glycosylphosphatidylinositol-linked, cell surface-associated aspartyl proteases (CgYapsins, CgYps1-11). We have recently characterized the secretome of C. glabrata wild-type and aspartyl protease-deficient mutant strains, and showed that the GPI-anchored aspartyl proteases are both bonafide constituents and key modulators of the C. glabrata secretome. Further, besides elucidating the role of CgYapsins in the suppression of the host pro-inflammatory immune response, we have identified the flavodoxin-like protein CgPst2 as a substrate of the CgYps1 protease and demonstrated that the CgYps1-mediated cleavage of CgPst2 is pivotal to oligomerization and activity, and functions of CgPst2 in quinone detoxification. These findings underscoring the importance of multifunctional CgYapsins in the physiology and pathogenesis of C. glabrata will be presented.
S9.5d Genotyping of Malassezia species from seborrheic dermatitis/dandruff patients
Authors: Honnavar Prasanna , Chakrabarti Arunaloke , Dogra Sunil , Lakshmi PVM , Rudramurthy Shivaprakash 
Published: September 2022

Abstract

S9.5 Malassezia: pathogenesis and disease, September 23, 2022, 4:45 PM - 6:15 PM

Objectives
Seborrheic dermatitis/dandruff (SD/D) are common chronic inflammatory skin disorders characterized by recurrent greasy scales with erythema and itchiness. Malassezia lobose and M. restricta are the predominant agents associated with SD/D. The aim of the study was to differentiate Malassezia strains causing SD/D from commensal using a highly discriminatory DNA fingerprinting technique, Fluorescent Amplified Fragment Length Polymorphism (FAFLP).

Methods
A total of 154 (M. globosa, n = 85; M. restricta, n = 55; M. arunalokei, n = 14; standard strains, n = 3) isolates from SD/D patients and healthy controls were analyzed using FAFLP. DNA sample was digested with restriction enzymes EcoRI and HindIII, and the fragments were linked to prepared adapters. Pre-selective followed by selective amplification reactions were performed using EcoRI-AC [6-carboxyfluorescein (6-FAM) labeled] and HindIII-T selective primers. The similarity coefficient was determined by Pearson correlation with negative similarities clip to zero. The densitometric curve cluster analysis was performed by unweighted pair group method with arithmetic means using Bionumerics software. The similarity co-efficient of 70% was taken as a cut-off.

Results
M. restricta and M. arunalokei isolates had a similarity co-efficient of 20%, whereas it was 50% among M. restricta and 60% among M. arunalokei isolates (Fig. 1). Majority of the isolates (n = 38.69%) clustered to form FAFLP type-I, followed by type-II (n = 14.25%), and type-III (n = 3.6%). All three FAFLP types formed tight clustering among themselves (&gt;80% similarity co-efficient) showing less genetic diversity within each FAFLP type. Type-II clustered strains were isolated from the scalp of SD/D patients (P &lt;.05). M. arunalokei isolates were clustered into two FAFLP types (P = .05). All FAFLP type-I isolates (n = 10,71%) were from the scalp of moderate and severe SD/D patients, whereas all type-II isolates (n = 4,29%) were from nasolabial folds of either SD/D patients or healthy controls. All 11 FAFLP types of M. globosa formed very loose structured cluster showing high genetic diversity in intra and inter-FAFLP types (Fig. 2). Majority of the isolates (n = 63,74%) clustered to form FAFLP type-II, followed by type X (n = 5.6%), type-I (n = 4.5%), type-III (n = 3.3.5%), type-IV (n = 3.3.5%), type-V (n = 2.2%), type-VIII (n = 2.2%), and type-VI, VII, IX, XI (n = 1.1% each). No geographic specific isolate clustering was observed in FAFLP.

Conclusion
M. restricta type-II and M. arunalokei type-I strains were isolated only from the scalp of moderate to severe forms of SD/D. However, no such severity-specific clustering was observed in M. globosa. The results strongly suggest the role of certain genotypes of M. restricta and M. arunalokei in the causation of SD/D.
Liposomal amphotericin B exposure in critically ill patients: a prospective pharmacokinetic study
Authors: Van Daele Ruth , Wauters Joost , Elkayal Omar , Dreesen Erwin , Debaveye Yves , Lagrou Katrien , de Beer Yvo , Maertens Johan , Brüggemann Roger J , Spriet Isabel 
Published: September 2022

Abstract
Liposomal amphotericin B (L-AmB) is a broad-spectrum antifungal drug. Little is known about its pharmacokinetics (PK) in critically ill patients. The aim of this study was to document the PK of L-AmB in this population. It was also explored if covariates may be identified that influence its exposure. All adult, critically ill patients (at the intensive care unit or hematology ward) treated with L-AmB between October 2016 and January 2020 were eligible for this study. The administered dose was left at the discretion of the treating clinician. Plasma samples were collected at predose and 1, 2, 4, 8, 12, 16, 20 and 24 h postdose at an early (day 2–3) and/or later (≥ day 6) treatment day. Additionally, daily trough concentrations were collected until day 14. Of 33 included patients, 31 were evaluable; their median [IQR] age and body weight was 59 [54–64] years and 68 [59–77] kg, respectively. L-AmB was administered at doses between 2.7 mg/kg and 12.3 mg/kg, with a median [IQR] trough concentration of 3.1 [2.0–4.7] mg/l. The overall median area under the 24 h concentration–time curve (AUC0-24) and peak plasma concentration (Cmax) were 169.0 [117.0–253.0] mg h/l and 23.2 [16.9–33.7] mg/l, respectively. A considerable intra- and interpatient PK variability for Cmax and AUC0-24 was observed but no explaining variables, except the administered dose, could be identified. The PK of L-AmB in critically ill patients was documented. A considerable variability in exposure was observed between and within patients; however, it was not associated with a multitude of patient-related characteristics.
Star cluster formation in clouds with externally driven turbulence
Authors: Smith Jamie D , Dale James E , Jaffa Sarah E , Krause Martin G H 
Published: September 2022

ABSTRACT
Star clusters are known to be formed in turbulent molecular clouds. How turbulence is driven in molecular clouds and what effect this has on star formation is still unclear. We compare a simulation setup with turbulent driving everywhere in a periodic box with a setup where turbulence is only driven around the outside of the box. We analyse the resulting gas distribution, kinematics, and the population of stars that are formed from the cloud. Both setups successfully produce a turbulent velocity field with a power-law structure function, the externally driven cloud has a more central, monolithic, clump, while the fully driven cloud has many smaller, more dispersed, clumps. The star formation follows the cloud morphology producing large clusters, with high star-forming efficiency in the externally driven simulations and sparse individual star formation with much lower star formation efficiency in the fully driven case. We conclude that the externally driven method, which resembles a Global Hierarchical Collapse (GHC) scenario, produces star clusters that more closely match with observations.
What powers galactic outflows: nuclear starbursts or AGN?
Authors: Ishibashi W , Fabian A C 
Published: September 2022

ABSTRACT
Galactic outflows can be powered either by nuclear starbursts (SB) or active galactic nuclei (AGNs). It has been argued that extreme starbursts can power extreme outflows, without the need to invoke AGN feedback. However, contributions from past and/or hidden AGN activity cannot be ruled out. Here, we constrain the potential role of the central black hole in driving powerful outflows in starburst galaxies (with no sign of ongoing AGN activity). We examine whether the galactic outflows can be explained by AGN luminosity evolution in the framework of our AGN ‘radiative dusty feedback’ scenario. We show that the outflow energetics of starburst galaxies in the local Universe can be quantitatively reproduced by power-law and exponential luminosity decays, coupled with radiation trapping. Likewise, a combination of heavy obscuration and mild luminosity decay may account for the energetics of galactic outflows observed in dusty star-forming galaxies in the early Universe. We discuss different physical arguments for SB versus AGN outflow-driving, and conclude that the latter can have a major impact on the evolution of galaxies.