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1.
Res Sq ; 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38903078

RESUMO

The opportunistic fungal pathogen Candida parapsilosis is a major causative agent of candidiasis leading to death in immunocompromised individuals. Azoles are the first line of defense in treatment by inhibiting ERG11, involved in the synthesis of ergosterol, the main sterol fungal sterol. Resistance to azoles is on the increase worldwide including in Lebanon. The purpose of this study is to characterize nine hospital isolates labeled as C. parapsilosis: four resistant and five sensitive to fluconazole. Phenotypic characterization was achieved through a battery of tests that target pathogenicity attributes such as virulence, biofilm formation, stress resistance, and ergosterol content. Genotypic analysis was done through whole genome sequencing to mutations in key virulence and resistance genes. Phylogenetic comparison was performed to determine strain relatedness and clonality. Genomic data and phylogenetic analysis revealed that three of the nine C. parapsilosis isolates were misidentified; two as C. orthopsilosis and C. metapsilosis belonging to the C. parapsilosis complex, while the third was C. albicans. Moreover, several known and novel mutations in key drug resistance and virulence genes were identified such as ERG11, ERG3, ERG6, CDR1, and FAS2. Phylogenetic analysis revealed a high degree of relatedness and clonality within our C. parapsilosis isolates. Our results showed that resistant isolates had no increased ergosterol content, no statistically significant difference in virulence, but exhibited an increase in biofilm content compared to the sensitive isolates. In conclusion, our study, the first of its kind in Lebanon, suggests several mechanisms of antifungal drug resistance in C. parapsilosis hospital isolates.

2.
J Fungi (Basel) ; 10(5)2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38786702

RESUMO

BACKGROUND: The pathogenic fungus Candida albicans is a leading agent of death in immunocompromised individuals with a growing trend of antifungal resistance. METHODS: The purpose is to induce resistance to drugs in a sensitive C. albicans strain followed by whole-genome sequencing to determine mechanisms of resistance. Strains will be assayed for pathogenicity attributes such as ergosterol and chitin content, growth rate, virulence, and biofilm formation. RESULTS: We observed sequential increases in ergosterol and chitin content in fluconazole-resistant isolates by 78% and 44%. Surface thickening prevents the entry of the drug, resulting in resistance. Resistance imposed a fitness trade-off that led to reduced growth rates, biofilm formation, and virulence in our isolates. Sequencing revealed mutations in genes involved in resistance and pathogenicity such as ERG11, CHS3, GSC2, CDR2, CRZ2, and MSH2. We observed an increase in the number of mutations in key genes with a sequential increase in drug-selective pressures as the organism increased its odds of adapting to inhospitable environments. In ALS4, we observed two mutations in the susceptible strain and five mutations in the resistant strain. CONCLUSION: This is the first study to induce resistance followed by genotypic and phenotypic analysis of isolates to determine mechanisms of drug resistance.

3.
Cereb Cortex ; 34(5)2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38760318

RESUMO

Cortical parvalbumin interneurons (PV+) are major regulators of excitatory/inhibitory information processing, and their maturation is associated with the opening of developmental critical periods (CP). Recent studies reveal that cortical PV+ axons are myelinated, and that myelination along with perineuronal net (PNN) maturation around PV+ cells is associated with the closures of CP. Although PV+ interneurons are susceptible to early-life stress, their relationship between their myelination and PNN coverage remains unexplored. This study compared the fine features of PV+ interneurons in well-characterized human post-mortem ventromedial prefrontal cortex samples (n = 31) from depressed suicides with or without a history of child abuse (CA) and matched controls. In healthy controls, 81% of all sampled PV+ interneurons displayed a myelinated axon, while a subset (66%) of these cells also displayed a PNN, proposing a relationship between both attributes. Intriguingly, a 3-fold increase in the proportion of unmyelinated PV+ interneurons with a PNN was observed in CA victims, along with greater PV-immunofluorescence intensity in myelinated PV+ cells with a PNN. This study, which is the first to provide normative data on myelination and PNNs around PV+ interneurons in human neocortex, sheds further light on the cellular and molecular consequences of early-life adversity on cortical PV+ interneurons.


Assuntos
Interneurônios , Parvalbuminas , Córtex Pré-Frontal , Humanos , Córtex Pré-Frontal/patologia , Córtex Pré-Frontal/metabolismo , Parvalbuminas/metabolismo , Interneurônios/patologia , Interneurônios/metabolismo , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Bainha de Mielina/patologia , Bainha de Mielina/metabolismo , Suicídio , Idoso , Autopsia , Maus-Tratos Infantis/psicologia , Adulto Jovem
4.
Mycoses ; 67(6): e13750, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38813959

RESUMO

BACKGROUND: The prevalence of Candida glabrata healthcare-associated infections is on the rise worldwide and in Lebanon, Candida glabrata infections are difficult to treat as a result of their resistance to azole antifungals and their ability to form biofilms. OBJECTIVES: The first objective of this study was to quantify biofilm biomass in the most virulent C. glabrata isolates detected in a Lebanese hospital. In addition, other pathogenicity attributes were evaluated. The second objective was to identify the mechanisms of azole resistance in those isolates. METHODS: A mouse model of disseminated systemic infection was developed to evaluate the degree of virulence of 41 azole-resistant C. glabrata collected from a Lebanese hospital. The most virulent isolates were further evaluated alongside an isolate having attenuated virulence and a reference strain for comparative purposes. A DNA-sequencing approach was adopted to detect single nucleotide polymorphisms (SNPs) leading to amino acid changes in proteins involved in azole resistance and biofilm formation. This genomic approach was supported by several phenotypic assays. RESULTS: All chosen virulent isolates exhibited increased adhesion and biofilm biomass compared to the isolate having attenuated virulence. The amino acid substitutions D679E and I739N detected in the subtelomeric silencer Sir3 are potentially involved- in increased adhesion. In all isolates, amino acid substitutions were detected in the ATP-binding cassette transporters Cdr1 and Pdh1 and their transcriptional regulator Pdr1. CONCLUSIONS: In summary, increased adhesion led to stable biofilm formation since mutated Sir3 could de-repress adhesins, while decreased azole susceptibility could result from mutations in Cdr1, Pdh1 and Pdr1.


Assuntos
Antifúngicos , Biofilmes , Candida glabrata , Candidíase , Farmacorresistência Fúngica , Mutação , Biofilmes/crescimento & desenvolvimento , Candida glabrata/genética , Candida glabrata/efeitos dos fármacos , Candida glabrata/isolamento & purificação , Candida glabrata/patogenicidade , Candida glabrata/fisiologia , Líbano , Animais , Camundongos , Farmacorresistência Fúngica/genética , Antifúngicos/farmacologia , Humanos , Virulência/genética , Candidíase/microbiologia , Proteínas Fúngicas/genética , Polimorfismo de Nucleotídeo Único , Modelos Animais de Doenças , Azóis/farmacologia , Testes de Sensibilidade Microbiana , Hospitais , Feminino
5.
J Glob Antimicrob Resist ; 37: 62-68, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38408565

RESUMO

OBJECTIVES: This study aimed to identify the resistance mechanisms to micafungin and fluconazole in a clinical isolate of Candida glabrata. METHODS: The isolate was whole-genome sequenced to identify amino acid changes in key proteins involved in antifungal resistance, and the isolate was further characterised by pathogenicity-related phenotypic assays that supported the sequencing results. RESULTS: Amino acid substitutions were detected in 8 of 17 protein candidates. Many of these substitutions were novel, including in CHS3, CHS3B, and KRE5, which are involved in the development of micafungin resistance. Regarding fluconazole resistance, overexpression of efflux pumps was observed. Our isolate did not exhibit an increased virulence potential compared with the control strain; however, a significant increase in chitin content and potential to resist the cell surface disruptant sodium dodecyl sulphate was observed. CONCLUSIONS: This clinical Candida glabrata isolate experienced a change in cell wall architecture, which correlates with the development of micafungin resistance.


Assuntos
Antifúngicos , Candida glabrata , Quitina , Farmacorresistência Fúngica , Micafungina , Testes de Sensibilidade Microbiana , Candida glabrata/efeitos dos fármacos , Candida glabrata/genética , Candida glabrata/isolamento & purificação , Antifúngicos/farmacologia , Humanos , Micafungina/farmacologia , Quitina/metabolismo , Quitina/farmacologia , Farmacorresistência Fúngica/genética , Fluconazol/farmacologia , Sequenciamento Completo do Genoma , Candidíase/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Substituição de Aminoácidos , Parede Celular
6.
J Neurooncol ; 165(1): 209-218, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37889443

RESUMO

PURPOSE: New treatments are needed to improve the overall survival of patients with glioblastoma Metformin is known for anti-tumorigenic effects in cancers, including breast and pancreas cancers. In this study, we assessed the association between metformin use and overall survival in glioblastoma patients. METHODS: We retrospectively studied 241 patients who underwent surgery at diagnosis of glioblastoma between 2014 and 2018. Metformin was used for pre-existing type 2 diabetes mellitus or in the prevention or management of glucocorticoid induced hyperglycemia. Kaplan-Meier curves and log-rank p test were used for univariate analysis. Cox-proportional hazards model was used to generate adjusted hazard ratios for multivariate analysis. RESULTS: Metformin use was associated with longer survival in patients with tumors that had a methylated O6-methylguanine DNA methyltransferase gene (MGMT) promoter (484 days 95% CI: 56-911 vs. 394 days 95% CI: 249-538, Log-Rank test: 6.5, p = 0.01). Cox regression analysis shows that metformin associates with lower risk of death at 2 years in patients with glioblastoma containing a methylated MGMT promoter (aHR = 0.497, 95% CI 0.26-0.93, p = 0.028). CONCLUSION: Our findings suggest a survival benefit with metformin use in patients with glioblastomas having methylation of the MGMT promoter.


Assuntos
Neoplasias Encefálicas , Diabetes Mellitus Tipo 2 , Glioblastoma , Metformina , Humanos , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/patologia , Metiltransferases/genética , Estudos Retrospectivos , Metformina/uso terapêutico , Diabetes Mellitus Tipo 2/genética , Metilação de DNA , Metilases de Modificação do DNA/genética , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Inativação Gênica , Enzimas Reparadoras do DNA/genética , Prognóstico , Proteínas Supressoras de Tumor/genética
7.
Microorganisms ; 9(6)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071222

RESUMO

Candida albicans is an opportunistic pathogenic fungus responsible for high mortality rates in immunocompromised individuals. Azole drugs such as fluconazole are the first line of therapy in fungal infection treatment. However, resistance to azole treatment is on the rise. Here, we employ a tandem mass spectrometry approach coupled with a bioinformatics approach to identify cell wall proteins present in a fluconazole-resistant hospital isolate upon drug exposure. The isolate was previously shown to have an increase in cell membrane ergosterol and cell wall chitin, alongside an increase in adhesion, but slightly attenuated in virulence. We identified 50 cell wall proteins involved in ergosterol biosynthesis such as Erg11, and Erg6, efflux pumps such as Mdr1 and Cdr1, adhesion proteins such as Als1, and Pga60, chitin deposition such as Cht4, and Crh11, and virulence related genes including Sap5 and Lip9. Candidial proteins identified in this study go a long way in explaining the observed phenotypes. Our pilot study opens the way for a future large-scale analysis to identify novel proteins involved in drug-resistance mechanisms.

8.
Fungal Genet Biol ; 153: 103575, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34033880

RESUMO

Hospital infections caused by the opportunistic fungus Candida albicans are increasingly common and life threatening. The first line of defense consists of administering antifungal drugs such as azoles including fluconazole that prevent ergosterol biosynthesis. C. albicans is rapidly developing resistance towards antifungal drugs through various mechanisms including mutations in ERG11 which is a gene involved in the ergosterol biosynthesis pathway. These mutations prevent the binding of the drug and inactivate ergosterol synthesis. Alternatively, upregulation of cell membrane ergosterol content generates resistance by countering the effect of the drug. In this study we sequenced the ERG11 gene in 6 fluconazole sensitive and 8 fluconazole resistant C. albicans isolates recovered from clinical settings in Lebanon and quantified the ergosterol content of their plasma membranes to identify mechanisms linked to fluconazole resistance. A number of pathogenicity attributes were also analyzed to determine any correlation with fluconazole resistance. Our results revealed an increase in ergosterol content in the fluconazole resistant isolates. In addition, we identified both novel and previously reported amino acid substitutions in ERG11 as well as frameshift mutations that might contribute to resistance. The fluconazole resistant isolates did not exhibit an increased virulence potential in a mouse model of systemic infection and showed decreased in vitro potential to form biofilms. No discrepancy between drug resistant and sensitive isolates to cell surface disrupting agents was observed. This approach is the first of its kind to be carried out in Lebanon to identify possible mechanisms and phenotypes of drug resistant C. albicans isolates.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/patogenicidade , Candidíase/microbiologia , Fluconazol/farmacologia , Genes Fúngicos , Substituição de Aminoácidos , Animais , Biofilmes/crescimento & desenvolvimento , Candida albicans/genética , Candida albicans/crescimento & desenvolvimento , Parede Celular/ultraestrutura , Quitina/análise , Infecção Hospitalar/microbiologia , Farmacorresistência Fúngica , Ergosterol/metabolismo , Feminino , Mutação da Fase de Leitura , Proteínas Fúngicas/genética , Humanos , Líbano , Camundongos , Virulência
9.
J Med Microbiol ; 70(4)2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33909551

RESUMO

Candida albicans is an opportunistic pathogen accounting for the majority of cases of Candida infections. Currently, C. albicans are developing resistance towards different classes of antifungal drugs and this has become a global health burden that does not spare Lebanon. This study aims at determining point mutations in genes known to be involved in resistance acquisition and correlating resistance to virulence and ergosterol content in the azole resistant C. albicans isolate CA77 from Lebanon. This pilot study is the first of its kind to be implemented in Lebanon. We carried out whole genome sequencing of the azole resistant C. albicans isolate CA77 and examined 18 genes involved in antifungal resistance. To correlate genotype to phenotype, we evaluated the virulence potential of this isolate by injecting it into BALB/c mice and we quantified membrane ergosterol. Whole genome sequencing revealed that eight out of 18 genes involved in antifungal resistance were mutated in previously reported and novel residues. These genotypic changes were associated with an increase in ergosterol content but no discrepancy in virulence potential was observed between our isolate and the susceptible C. albicans control strain SC5314. This suggests that antifungal resistance and virulence potential in this antifungal resistant isolate are not correlated and that resistance is a result of an increase in membrane ergosterol content and the occurrence of point mutations in genes involved in the ergosterol biosynthesis pathway.


Assuntos
Candida albicans/efeitos dos fármacos , Candida albicans/genética , Farmacorresistência Fúngica/genética , Sequenciamento Completo do Genoma , Animais , Azóis/farmacologia , Candida albicans/química , Candida albicans/patogenicidade , Ergosterol/análise , Genótipo , Humanos , Líbano , Camundongos , Camundongos Endogâmicos BALB C , Fenótipo , Projetos Piloto , Mutação Puntual , Virulência
10.
Mol Med Rep ; 22(3): 1910-1920, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32583004

RESUMO

To the best of our knowledge, the vertebrate apolipoprotein L (APOL) family has not previously been ascribed to any definite pathophysiological function, although the conserved BH3 protein domain suggests a role in programmed cell death or an interference with mitochondrial processes. In the present study, the human APOL1 was expressed in the yeast Saccharomyces cerevisiae in order to determine the molecular action of APOL1. APOL1 inhibited cell proliferation in a non­fermentable carbon source, such as glycerol, while it had no effect on proliferation in fermentable carbon sources, such as galactose. APOL1, expressed in yeast, is localized in the mitochondrial fraction, as determined via western blotting. APOL1 induced a loss of mitochondrial function, demonstrated by a loss of respiratory index, and mitochondrial membrane potential. Green fluorescent protein tagging of mitochondrial protein revealed that APOL1 was associated with abnormal mitochondrial and lysosomal morphologies, observed by a loss of the normal mitochondrial tubular network. Thus, the results of the present study suggest that APOL1 could be a physiological regulator of mitochondrial function.


Assuntos
Apolipoproteína L1/genética , Mitocôndrias/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Apolipoproteína L1/metabolismo , Fermentação , Glicerol/metabolismo , Humanos , Potencial da Membrana Mitocondrial , Viabilidade Microbiana , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
11.
J Anaesthesiol Clin Pharmacol ; 35(3): 335-339, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31543581

RESUMO

BACKGROUND AND AIMS: Rapid sequence induction, with the application of cricoid pressure is an accepted practice during induction of general anesthesia in pregnant patients to prevent pulmonary apiration. We found no prior studies assessing the accuracy of locating the cricoid cartilage by professional caregivers, and therefore conducted an observational study to assess the ability of different caregivers - anesthesia consultants, anesthesia residents, respiratory therapists (RTs), and nurses, in the obstetric care unit, to correctly identify the cricoid cartilage of parturients. We hypothesized that anesthesia consultants would be most accurate. MATERIAL AND METHODS: Institutional REB approval was obtained, as was written informed consent from all participants in the study. The subjects were made up of thirty healthy obstetric patients scheduled for elective cesarean delivery. Their cricoid cartilages were assessed by 53 caregivers (assessors). Localization of the cricoid cartilage by assessors was considered accurate if it was within 5 mm of the sonographically identified mark. The difficulty in localization was reported on a VAS scale and the time taken for localization was recorded. RESULTS: Data from 30 subjects and 53 assessors (13 anesthesia consultants, 12 residents, 13 RTs, and 15 nurses) performing a total of 60 evaluations (some assessors evaluated 2 subjects) were analyzed. About 60% of RTs, 53% of anesthesia residents, 40% of anesthesia consultants, and 13% of nurses correctly identified the cricoid cartilage. No differences in caregivers'perception of difficulty were found, but RTs were the quickest at identification (P < 0.001 vs anesthesia consultants; P = 0.002 vs residents; P = 0.071 vs nurses). CONCLUSION: RTs were the most successful and accurate in identifying the cricoid cartilage of parturients among the different groups of professional caregivers.

12.
J Microbiol Biotechnol ; 29(11): 1806-1816, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31546294

RESUMO

Candida albicans is an opportunistic fungus possessing multiple virulence factors controlling pathogenicity. Cell wall proteins are the most important among these factors, being the first elements contacting the host. Ddr48 is a cell wall protein consisting of 212 amino acids. A DDR48 haploinsufficient mutant strain was previously found necessary for proper oxidative stress response and drug resistance. In this study, we aimed to further elucidate the role of Ddr48 by performing additional phenotypic characterization assays. A combinatory proteomic and bioinformatics approach was also undertaken to determine differentially expressed cell wall proteins. Results showed that the mutant strain exhibited a 10% decrease in adhesion mirrored by a 20% decrease in biofilm formation, and slight sensitivity to menadione, diamide, and SDS. Both strains showed similar hyphae formation, virulence, temperature tolerance, and calcofluor white and Congo red sensitivities. Furthermore, a total of 8 and 10 proteins were identified exclusively in the wild-type strain grown under filamentous and nonfilamentous conditions respectively. Results included proteins responsible for superoxide stress resistance (Sod4 and Sod6), adhesion (Als3, Hyr4, Pmt1, and Utr2), biofilm formation (Hsp90, Ece1, Rim9, Ipp1, and Pra1) and cell wall integrity (Utr2 and Pga4). The lack of detection of these proteins in the mutant strain correlates with the observed phenotypes.


Assuntos
Candida albicans/fisiologia , Parede Celular/metabolismo , Proteínas Fúngicas/genética , Estresse Oxidativo/genética , Fatores de Virulência/genética , Aderência Bacteriana/genética , Biofilmes/crescimento & desenvolvimento , Candida albicans/genética , Candida albicans/metabolismo , Parede Celular/genética , Farmacorresistência Fúngica/genética , Proteínas Fúngicas/metabolismo , Hifas/genética , Hifas/metabolismo , Mutação , Fenótipo , Proteômica , Fatores de Virulência/metabolismo
13.
Fungal Genet Biol ; 127: 12-22, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30794951

RESUMO

The fungus Candida albicans is both a commensal and an opportunistic human pathogen, present as part of the normal human microflora causing serious mucosal, and systemic life threatening infections. The antifungal drug caspofungin of the echinocandin family is the latest generation of antifungal drugs to be developed. It functions by inhibiting glucan synthase thus weakening the fungal cell wall leading to death. Recently reports of resistance to caspofungin have been reported mainly through mutations in the FKS encoded subunits of glucan synthase at hot spot 1 (amino acids 641 to 649, FSTLSLRDP) and hot spot 2 (amino acids 1357 to 1364, DWIRRYTL). Our study aimed at sequencing both hot spots from 16 C. albicans Lebanese hospital isolates resistant and sensitive to caspofungin to determine whether mutations in these hot spots are present, and whether such mutations also impart resistance to our isolates. In addition, we wanted to determine any relationship between resistance and pathogenicity related attributes such as virulence, resistance to cell wall disrupting agents, biofilm formation, and cell wall chitin deposition. Five isolates were found to contain mutations with the mutations restricted to resistant strains. Within hot spot 1 substitution at positions S642, T643, L644, R647, and D648 were found, while within hot spot 2 substitutions at positions L1364, T1363, and R1360, W1358 and R1361 were identified with some of the mutations not previously documented. Strains that were resistant to caspofungin also showed increased resistance to Congo red but decreased biofilm formation and attenuated virulence in a mouse model of infection. Caspofungin sensitive strains showed decreased resistance to Congo red yet increased virulence and biofilm formation. Chitin content analysis showed that caspofungin resistant strains had elevated levels of chitin resulting in cell wall thickening that counters the effect of caspofungin, while sensitive strains showed decreased chitin content. Our results demonstrate an inverse correlation between resistance and virulence whereby resistance is due to thickening of the cell wall preventing the cell from gaining virulence attributes, while a more susceptible cell wall increases susceptibility to drugs but allows increased virulence.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Farmacorresistência Fúngica/genética , Animais , Biofilmes , Candida albicans/patogenicidade , Candidíase/microbiologia , Caspofungina/farmacologia , Vermelho Congo/farmacologia , Proteínas Fúngicas/genética , Genótipo , Hospitais/estatística & dados numéricos , Humanos , Líbano , Camundongos , Testes de Sensibilidade Microbiana , Mutação , Fenótipo , Virulência
14.
EuPA Open Proteom ; 18: 1-6, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29928583

RESUMO

We previously characterized Pga1, a Candida albicans (C. albicans) cell wall protein necessary for proper virulence, adhesion, and resistance to oxidative stress. By utilizing tandem mass spectrometry coupled with bioinformatics to investigate cell wall proteome expression in a pga1 null fourteen and 36 proteins were identified in the wild type grown under filamentous and non-filamentous conditions respectively, but were not detected in the mutant, including members of the PGA GPI anchored family. Virulence and adhesion proteins such as Hsp 90, Sap10, Cdc11, Int 3 and members of the lipase family were also identified exclusively in the wild type.

15.
Curr Mol Pharmacol ; 11(3): 211-225, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29741145

RESUMO

BACKGROUND: Candida albicans is present as part of the normal gut flora and detected in the oral cavities and GI tracts of around fifty percent of adults. Benign colonization can turn pathogenic causing a variety of mild to severe infections. In a pathogen, the cell wall and cell surface proteins are major antigenic determinants and drug targets as they are the primary structures that contact the host. Cell surface proteins perform a variety of functions necessary for virulence such as adhesion, host degradation, resistance to oxidative stress, and drug resistance. We have previously characterized Hwp2, a C. albicans cell wall adhesin shown to play a major role in the cell wall architecture and function as hwp2 mutants were deficient in chitin deposition, filamentation, adhesion and invasive growth, virulence, and resistance to oxidative stress. OBJECTIVE/METHOD: Here, we utilized tandem mass spectrometry coupled with a bioinformatics approach to differentially profile the cell wall proteome of a wild-type strain compared to an hwp2 null mutant to determine key differentially expressed proteins. RESULT: Many proteins identified exclusively in the wild-type go a long way in explaining the abovementioned phenotypes. These include virulence factors such as members of the SAP family including Sap4, Sap5, and Sap10, as well as several lipases involved in host degradation. We also identified members of the PGA family of proteins Pga28, Pga32, Pga41 and Pga50, which function in adhesion, Cht2 a chitinase involved in chitin remodeling, and several proteins that function in promoting filamentation such as Phr1, Mts1, and Rbr1.


Assuntos
Candida albicans/metabolismo , Parede Celular/metabolismo , Proteínas Fúngicas/metabolismo , Mutação/genética , Proteoma/metabolismo , Proteômica/métodos , Espectrometria de Massas em Tandem/métodos , Sequência de Aminoácidos , Candida albicans/crescimento & desenvolvimento , Proteínas Fúngicas/química
16.
PLoS One ; 13(3): e0194403, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29554112

RESUMO

We have previously characterized Pir32, a Candia albicans cell wall protein that we found to be involved in filamentation, virulence, chitin deposition, and resistance to oxidative stress. Other than defining the cell shape, the cell wall is critical for the interaction with the surrounding environment and the point of contact and interaction with the host surface. In this study, we applied tandem mass spectrometry combined with bioinformatics to investigate cell wall proteome changes in a pir32 null strain. A total of 16 and 25 proteins were identified exclusively in the null mutant strains grown under non-filamentous and filamentous conditions. These proteins included members of the PGA family with various functions, lipase and the protease involved in virulence, superoxide dismutases required for resisting oxidative stress, alongside proteins required for cell wall remodeling and synthesis such as Ssr1, Xog1, Dfg5 and Dcw1. In addition proteins needed for filamentation like Cdc42, Ssu81 and Ucf1, and other virulence proteins such as Als3, Rbt5, and Csa2 were also detected. The detection of these proteins in the mutant and their lack of detection in the wild type can explain the differential phenotypes previously observed.


Assuntos
Candida albicans , Parede Celular , Proteínas Fúngicas , Estresse Oxidativo/genética , Candida albicans/genética , Candida albicans/metabolismo , Candida albicans/patogenicidade , Parede Celular/genética , Parede Celular/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
17.
Yeast ; 31(11): 441-8, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25231799

RESUMO

Candida albicans is a common opportunistic pathogen that causes a variety of diseases in immunocompromised hosts. In a pathogen, cell wall proteins are important virulence factors. We previously characterized Dse1 as a cell wall protein necessary for virulence and resistance to cell surface-disrupting agents, such as Calcofluor white, chitin deposition, proper adhesion and biofilm formation. In the absence of decomplexation, our objectives were to investigate differential proteomic expression of a DSE1 mutant strain compared to the wild-type strain. The strains were grown under filamentous and non-filamentous conditions. The extracted cell proteome was subjected to tryptic digest, followed by generation of peptide profiles using MALDI-TOF MS. Generated peptide profiles were analysed and unique peaks for each strain and growth condition mined against a Candida database, allowing protein identification. The DSE1 mutant was shown to lack the chitin biosynthesis protein Chs5, explaining the previously observed decrease in chitin biosynthesis. The wild-type strain expressed Pra1, involved in pH response and zinc acquisition, Atg15, a lipase involved in virulence, and Sod1, required for oxidative stress tolerance, in addition to proteins involved in protein biosynthesis, explaining the increase in total protein content observed compared to the mutants strain. The mutant, on the other hand, expressed glucoamylase 1, a cell wall glycoprotein involved in carbohydrate metabolism cell wall degradation and biofilm formation. As such, MALDI-TOF MS is a reliable technique in identifying mutant-specific protein expression in C. albicans.


Assuntos
Candida albicans/química , Candida albicans/citologia , Proteínas Fúngicas/análise , Proteoma/análise , Candida albicans/crescimento & desenvolvimento , Proteômica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
18.
Biomed Res Int ; 2014: 931372, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24982915

RESUMO

As leading opportunistic fungal pathogens identification and subtyping of Candida species are crucial in recognizing outbreaks of infection, recognizing particularly virulent strains, and detecting the emergence of drug resistant strains. In this study our objective was to compare identification of Candida albicans by the hospitals through the use of conventional versus identification based on the ITS (Internal Transcribed Spacer) and to assess biofilm forming capabilities, drug resistance patterns and correlate these with MLST typing. ITS typing revealed a 21.2% hospital misidentification rate. Multidrug resistance to three drugs out of four tested was detected within 25% of the isolates raising concerns about the followed treatment regimens. Drug resistant strains as well as biofilm formers were phylogenetically related, with some isolates with significant biofilm forming capabilities being correlated to those that were multidrug resistant. Such isolates were grouped closely together in a neighbor-joining tree generated by MLST typing indicating phylogenetic relatedness, microevolution, or recurrent infection. In conclusion, this pilot study gives much needed insight concerning C. albicans isolates circulating in Lebanese hospitals and is the first study of its kind correlating biofilm formation, antifungal resistance, and evolutionary relatedness.


Assuntos
Antifúngicos/farmacologia , Biofilmes/crescimento & desenvolvimento , Candida albicans/isolamento & purificação , Candida albicans/fisiologia , Farmacorresistência Fúngica/efeitos dos fármacos , Hospitais , Tipagem de Sequências Multilocus , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biofilmes/efeitos dos fármacos , Candida albicans/classificação , Candida albicans/efeitos dos fármacos , Criança , Pré-Escolar , DNA Espaçador Ribossômico/genética , Feminino , Humanos , Líbano , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Filogenia , Análise de Sequência de DNA , Adulto Jovem
19.
Gene ; 525(1): 136-40, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23644024

RESUMO

AIMS: The Natural Killer Cell Immunoglobulin-like Receptor (KIR) genotype profiling in Follicular Lymphoma has not been reported before in the literature. MATERIALS AND METHODS: DNA extracted from 20 Follicular Lymphoma patients and 62 healthy controls was analyzed for KIR genotyping using a polymerase chain reaction/sequence specific primers technique (PCR/SSP) for the presence of 16 KIR gene and pseudogene loci. RESULTS: The AA, AB, and BB genotype frequencies were, respectively, 20%, 60% and 20% with an A:B ratio of 1:1. KIR 2DL4, KIR 3DL2, KIR 3DL3, and KIR 3DP1*003 were presented in all individuals. No significant difference between patients and controls was detected. CONCLUSION: KIR genotyping profile does not seem to be associated with Follicular Lymphoma. The results presented in this pilot research represent the first international report about this important clinical entity.


Assuntos
Linfoma Folicular/genética , Receptores KIR/genética , Estudos de Casos e Controles , Frequência do Gene , Haplótipos , Humanos , Projetos Piloto
20.
Microbiology (Reading) ; 159(Pt 6): 1160-1164, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23558263

RESUMO

The opportunistic fungal pathogen Candida albicans is one of the leading agents of life-threatening infections affecting immunocompromised individuals. Many factors make C. albicans a successful pathogen. These include the ability to switch between yeast and invasive hyphal morphologies in addition to an arsenal of cell wall virulence factors such as lipases, proteases, dismutases and adhesins that promote the attachment to the host, a prerequisite for invasive growth. We have previously characterized Hwp2, a C. albicans cell wall protein which we found necessary for proper oxidative stress, biofilm formation and adhesion to host cells. Baker's yeast Saccharomyces cerevisiae also possesses adhesins that promote aggregation and flocculence. Flo11 is one such adhesin that has sequence similarity to Hwp2. Here we determined that transforming an HWP2 cassette can complement the lack of filamentation of an S. cerevisiae flo11 null strain and impart on S. cerevisiae adhesive properties similar to those of a pathogen.


Assuntos
Candida albicans/citologia , Candida albicans/genética , Proteínas Fúngicas/genética , Teste de Complementação Genética , Glicoproteínas de Membrana/deficiência , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Candida albicans/crescimento & desenvolvimento , Adesão Celular , Linhagem Celular , Células Epiteliais/microbiologia , Proteínas Fúngicas/metabolismo , Humanos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae
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