scholarly journals Glucosylceramide Plays a Role in Fungal Germination, Lipid Raft Organization and Biofilm Adhesion of the Pathogenic Fungus Scedosporium aurantiacum

2020 ◽  
Vol 6 (4) ◽  
pp. 345
Author(s):  
Victor Pereira Rochetti ◽  
Rodrigo Rollin-Pinheiro ◽  
Evely Bertulino de Oliveira ◽  
Mariana Ingrid Dutra da Silva Xisto ◽  
Eliana Barreto-Bergter

Infections caused by Scedosporium species present a wide range of clinical manifestations, from superficial to disseminated, especially in immunocompromised patients. Glucosylceramides (GlcCer) are glycosphingolipids found on the fungal cell surface and play an important role in growth and pathogenicity processes in different fungi. The present study aimed to evaluate the structure of GlcCer and its role during growth in two S. aurantiacum isolates. Purified GlcCer from both isolates were obtained and its chemical structure identified by mass spectrometry. Using ELISA and immunofluorescence techniques it was observed that germination and NaOH-treatment of conidia favor GlcCer exposure. Monoclonal anti-GlcCer antibody reduced germination when cultivated with the inhibitor of melanin synthesis tricyclazole and also reduced germ tube length of conidia, both cultivated or not with tricyclazole. It was also demonstrated that anti-GlcCer altered lipid rafts organization, as shown by using the fluorescent stain filipin, but did not affect the susceptibility of the cell surface to damaging agents. Anti-GlcCer reduced total biomass and viability in biofilms formed on polystyrene plates. In the presence of anti-GlcCer, germinated S. aurantiacum conidia and biofilms could not adhere to polystyrene with the same efficacy as control cells. These results highlight the relevance of GlcCer in growth processes of S. aurantiacum.

2019 ◽  
Author(s):  
Yuria Chihara ◽  
Yutaka Tanaka ◽  
Minoru Izumi ◽  
Daisuke Hagiwara ◽  
Akira Watanabe ◽  
...  

ABSTRACTThe pathogenic fungus Aspergillus fumigatus contains galactomannans localized on the surface layer of its cell walls, which are involved in various biological processes. Galactomannans comprise α-(1→2)-/α-(1→6)-mannan and β-(1→5)-/β-(1→6)-galactofuranosyl chains. We previously revealed that GfsA is a β-galactofuranoside β-(1→5)-galactofuranosyltransferase involved in the biosynthesis of β-(1→5)-galactofuranosyl chains. Here, we clarified the entire biosynthesis of β-(1→5)-galactofuranosyl chains in A. fumigatgus. Two paralogs exist within A. fumigatus: GfsB and GfsC. We show that GfsB and GfsC, in addition to GfsA, are β-galactofuranoside β-(1→5)-galactofuranosyltransferases by biochemical and genetic analyses. GfsA, GfsB, and GfsC can synthesize β-(1→5)-galactofuranosyl oligomers up to lengths of 7, 3, and 5 galactofuranoses within an established in vitro highly efficient assay of galactofuranosyltransferase activity. Structural analyses of galactomannans extracted from the strains ΔgfsB, ΔgfsC, ΔgfsAC, and ΔgfsABC revealed that GfsA and GfsC synthesized all β-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans, and GfsB exhibited limited function in A. fumigatus. The loss of β-(1→5)-galactofuranosyl residues decreased the hyphal growth rate and conidia formation ability as well as increased the abnormal hyphal branching structure and cell surface hydrophobicity, but this loss is dispensable for sensitivity to antifungal agents and virulence toward immune-compromised mice.IMPORTANCEβ-(1→5)-galactofuranosyl residues are widely distributed in the subphylum Pezisomycotina of the phylum Ascomycota. Pezizomycotina includes many plant and animal pathogens. Although the structure of β-(1→5)-galactofuranosyl residues of galactomannans in filamentous fungi was discovered long ago, it remains unclear which enzyme is responsible for biosynthesis of this glycan. Fungal cell wall formation processes are complicated, and information concerning glycosyltransferases is essential for their understanding. In this study, we show that GfsA and GfsC are responsible for the biosynthesis of all β-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans. The data presented here indicates that β-(1→5)-galactofuranosyl residues are involved in cell growth, conidiation, polarity, and cell surface hydrophobicity. Our new understanding of β-(1→5)-galactofuranosyl residue biosynthesis provides important novel insights into the formation of the complex cell wall structure and the virulence of the subphylum Pezisomycotina.


2010 ◽  
Vol 10 (1) ◽  
pp. 98-109 ◽  
Author(s):  
Lydia Schild ◽  
Antje Heyken ◽  
Piet W. J. de Groot ◽  
Ekkehard Hiller ◽  
Marlen Mock ◽  
...  

ABSTRACT The cell wall of the human-pathogenic fungus Candida albicans is a robust but also dynamic structure which mediates adaptation to changing environmental conditions during infection. Sap9 and Sap10 are cell surface-associated proteases which function in C. albicans cell wall integrity and interaction with human epithelial cells and neutrophils. In this study, we have analyzed the enzymatic properties of Sap9 and Sap10 and investigated whether these proteases cleave proteins on the fungal cell surface. We show that Sap9 and Sap10, in contrast to other aspartic proteases, exhibit a near-neutral pH optimum of proteolytic activity and prefer the processing of peptides containing basic or dibasic residues. However, both proteases also cleaved at nonbasic sites, and not all tested peptides with dibasic residues were processed. By digesting isolated cell walls with Sap9 or Sap10, we identified the covalently linked cell wall proteins (CWPs) Cht2, Ywp1, Als2, Rhd3, Rbt5, Ecm33, and Pga4 as in vitro protease substrates. Proteolytic cleavage of the chitinase Cht2 and the glucan-cross-linking protein Pir1 by Sap9 was verified using hemagglutinin (HA) epitope-tagged versions of both proteins. Deletion of the SAP9 and SAP10 genes resulted in a reduction of cell-associated chitinase activity similar to that upon deletion of CHT2 , suggesting a direct influence of Sap9 and Sap10 on Cht2 function. In contrast, cell surface changes elicited by SAP9 and SAP10 deletion had no major impact on the phagocytosis and killing of C. albicans by human macrophages. We propose that Sap9 and Sap10 influence distinct cell wall functions by proteolytic cleavage of covalently linked cell wall proteins.


mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuria Chihara ◽  
Yutaka Tanaka ◽  
Minoru Izumi ◽  
Daisuke Hagiwara ◽  
Akira Watanabe ◽  
...  

ABSTRACT The pathogenic fungus Aspergillus fumigatus contains galactomannans localized on the surface layer of its cell walls, which are involved in various biological processes. Galactomannans comprise α-(1→2)-/α-(1→6)-mannan and β-(1→5)-/β-(1→6)-galactofuranosyl chains. We previously revealed that GfsA is a β-galactofuranoside β-(1→5)-galactofuranosyltransferase involved in the biosynthesis of β-(1→5)-galactofuranosyl chains. In this study, we clarified the biosynthesis of β-(1→5)-galactofuranosyl chains in A. fumigatus. Two paralogs exist within A. fumigatus: GfsB and GfsC. We show that GfsB and GfsC, in addition to GfsA, are β-galactofuranoside β-(1→5)-galactofuranosyltransferases by biochemical and genetic analyses. GfsA, GfsB, and GfsC can synthesize β-(1→5)-galactofuranosyl oligomers at up to lengths of 7, 3, and 5 galactofuranoses within an established in vitro highly efficient assay of galactofuranosyltransferase activity. Structural analyses of galactomannans extracted from ΔgfsB, ΔgfsC, ΔgfsAC, and ΔgfsABC strains revealed that GfsA and GfsC synthesized all β-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans and that GfsB exhibited limited function in A. fumigatus. The loss of β-(1→5)-galactofuranosyl residues decreased the hyphal growth rate and conidium formation ability and increased the abnormal hyphal branching structure and cell surface hydrophobicity, but this loss is dispensable for sensitivity to antifungal agents and virulence toward immunocompromised mice. IMPORTANCE β-(1→5)-Galactofuranosyl residues are widely distributed in the subphylum Pezizomycotina of the phylum Ascomycota. Pezizomycotina includes many plant and animal pathogens. Although the structure of β-(1→5)-galactofuranosyl residues of galactomannans in filamentous fungi was discovered long ago, it remains unclear which enzyme is responsible for biosynthesis of this glycan. Fungal cell wall formation processes are complicated, and information concerning glycosyltransferases is essential for understanding them. In this study, we showed that GfsA and GfsC are responsible for the biosynthesis of all β-(1→5)-galactofuranosyl residues of fungal-type and O-mannose-type galactomannans. The data presented here indicate that β-(1→5)-galactofuranosyl residues are involved in cell growth, conidiation, polarity, and cell surface hydrophobicity. Our new understanding of β-(1→5)-galactofuranosyl residue biosynthesis provides important novel insights into the formation of the complex cell wall structure and the virulence of the members of the subphylum Pezizomycotina.


Author(s):  
А.Р. Зарипова ◽  
Л.Р. Нургалиева ◽  
А.В. Тюрин ◽  
И.Р. Минниахметов ◽  
Р.И. Хусаинова

Проведено исследование гена интерферон индуцированного трансмембранного белка 5 (IFITM5) у 99 пациентов с несовершенным остеогенезом (НО) из 86 неродственных семей. НО - клинически и генетически гетерогенное наследственное заболевание соединительной ткани, основное клиническое проявление которого - множественные переломы, начиная с неонатального периода жизни, зачастую приводящие к инвалидизации с детского возраста. К основным клиническим признакам НО относятся голубые склеры, потеря слуха, аномалия дентина, повышенная ломкость костей, нарушения роста и осанки с развитием характерных инвалидизирующих деформаций костей и сопутствующих проблем, включающих дыхательные, неврологические, сердечные, почечные нарушения. НО встречается как у мужчин, так и у женщин. До сих пор не определена степень генетической гетерогенности заболевания. На сегодняшний день известно 20 генов, вовлеченных в патогенез НО, и исследователи разных стран продолжают искать новые гены. В последнее десятилетие стало известно, что аутосомно-рецессивные, аутосомно-доминантные и Х-сцепленные мутации в широком спектре генов, кодирующих белки, которые участвуют в синтезе коллагена I типа, его процессинге, секреции и посттрансляционной модификации, а также в белках, которые регулируют дифференцировку и активность костеобразующих клеток, вызывают НО. Мутации в гене IFITM5, также называемом BRIL (bone-restricted IFITM-like protein), участвующем в формировании остеобластов, приводят к развитию НО типа V. До 5% пациентов имеют НО типа V, который характеризуется образованием гиперпластического каллуса после переломов, кальцификацией межкостной мембраны предплечья и сетчатым рисунком ламелирования, наблюдаемого при гистологическом исследовании кости. В 2012 г. гетерозиготная мутация (c.-14C> T) в 5’-нетранслируемой области (UTR) гена IFITM5 была идентифицирована как основная причина НО V типа. В представленной работе проведен анализ гена IFITM5 и идентифицирована мутация c.-14C>T, возникшая de novo, у одного пациента с НО, которому впоследствии был установлен V тип заболевания. Также выявлены три известных полиморфных варианта: rs57285449; c.80G>C (p.Gly27Ala) и rs2293745; c.187-45C>T и rs755971385 c.279G>A (p.Thr93=) и один ранее не описанный вариант: c.128G>A (p.Ser43Asn) AGC>AAC (S/D), которые не являются патогенными. В статье уделяется внимание особенностям клинических проявлений НО V типа и рекомендуется определение мутации c.-14C>T в гене IFITM5 при подозрении на данную форму заболевания. A study was made of interferon-induced transmembrane protein 5 gene (IFITM5) in 99 patients with osteogenesis imperfecta (OI) from 86 unrelated families and a search for pathogenic gene variants involved in the formation of the disease phenotype. OI is a clinically and genetically heterogeneous hereditary disease of the connective tissue, the main clinical manifestation of which is multiple fractures, starting from the natal period of life, often leading to disability from childhood. The main clinical signs of OI include blue sclera, hearing loss, anomaly of dentin, increased fragility of bones, impaired growth and posture, with the development of characteristic disabling bone deformities and associated problems, including respiratory, neurological, cardiac, and renal disorders. OI occurs in both men and women. The degree of genetic heterogeneity of the disease has not yet been determined. To date, 20 genes are known to be involved in the pathogenesis of OI, and researchers from different countries continue to search for new genes. In the last decade, it has become known that autosomal recessive, autosomal dominant and X-linked mutations in a wide range of genes encoding proteins that are involved in the synthesis of type I collagen, its processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells cause OI. Mutations in the IFITM5 gene, also called BRIL (bone-restricted IFITM-like protein), involved in the formation of osteoblasts, lead to the development of OI type V. Up to 5% of patients have OI type V, which is characterized by the formation of a hyperplastic callus after fractures, calcification of the interosseous membrane of the forearm, and a mesh lamellar pattern observed during histological examination of the bone. In 2012, a heterozygous mutation (c.-14C> T) in the 5’-untranslated region (UTR) of the IFITM5 gene was identified as the main cause of OI type V. In the present work, the IFITM5 gene was analyzed and the de novo c.-14C> T mutation was identified in one patient with OI who was subsequently diagnosed with type V of the disease. Three known polymorphic variants were also identified: rs57285449; c.80G> C (p.Gly27Ala) and rs2293745; c.187-45C> T and rs755971385 c.279G> A (p.Thr93 =) and one previously undescribed variant: c.128G> A (p.Ser43Asn) AGC> AAC (S / D), which were not pathogenic. The article focuses on the features of the clinical manifestations of OI type V, and it is recommended to determine the c.-14C> T mutation in the IFITM5 gene if this form of the disease is suspected.


2019 ◽  
Vol 72 (8) ◽  
pp. 1437-1441
Author(s):  
Pavel Dyachenko ◽  
Igor Filchakov ◽  
Anatoly Dyachenko ◽  
Victoria Kurhanskaya

Introduction: Viral encephalitis accounts for 40-70% of all cases worldwide, central nervous system infections pose a diagnostic challenge because clinical manifestations are not typically pathognomonic for specific pathogens, and a wide range of agents can be causative. The aim: To assess the diagnostic value of intrathecal synthesis of specific antibodies in patients with inflammatory lesions of the central nervous system. Materials and methods: Within the framework of the study, two groups of 90 people in each were formed from the patients with neuroinfections admitted to our Center. Intrathecal synthesis (ITS) of total (unspecific) IgG in members of one of group (group of compare) was determined. Brain synthesis of specific antibodies (Ab) to some neurotropic pathogens (herpes simplex virus 1/2, cytomegalovirus, Epstein-Barr virus, varicella zoster virus, rubella virus, Borrelies) was studied in the second group of patients (group of interest). There were no statistically significant differences between groups by gender and age. Encephalitis and encephalomyelitis prevailed among patients of both groups Results: ITS of total IgG was established in 30 (33.3 ± 6.1 %) patients of the first group with IgG index more than 0.6 indicating on inflammatory process in CNS and no marked changes of CSF. ITS of specific Ab was determined in 23 of 90 (25.6 ± 4.6 %) patients included into group of interest. In more than half of cases Ab to several infectious agents were detected simultaneously. ITS of various specificity, in particular, to measles and rubella viruses, and VZV, known as MRZ-reaction, is characteristic of some autoimmune lesions of CNS, multiple sclerosis first of all. In fact, further research of 5 patients with MRZ-reaction confirmed their autoimmune failure of CNS. Detection of ITS in the CSF samples didn’t depend on concentration of specific Ab in serum and CSF and wasn’t followed by HEB dysfunctions which were observed with the same frequency in patients with or without ITS (13.0 % and 13.6 % respectively). Conclusion: Specific Ab synthesis to several neurotropic pathogens in the CSF of significant part of examined patients was established. Thus, diagnostic value of ITS of specific immunoglobulins seems to be limited to cases in which autoimmune damage of the CNS is suspected.


2020 ◽  
Vol 16 (3) ◽  
pp. 241-247
Author(s):  
Atifete Ramosaj-Morina ◽  
Alije Keka-Sylaj ◽  
Arbana Baloku Zejnullahu ◽  
Lidvana Spahiu ◽  
Virgjina Hasbahta ◽  
...  

Background: Celiac disease is an immune-mediated disorder characterized by variable clinical manifestations, specific antibodies, HLA-DQ2/DQ8 haplotypes, and enteropathy. Objectives: The aim of this study was to present the clinical spectrum and patterns of celiac disease in Kosovar Albanian children. Methods: A cross-sectional retrospective study was performed with Albanian children aged 0-18 years, treated for celiac disease in the Pediatric Clinic, University Clinical Center of Kosovo from 2005 to 2016. Results: During the study period, 63 children were treated for celiac disease. The mean age at diagnosis was 5.5 years (SD ± 3.31). The mean age at celiac disease onset was 3.3 years (SD ± 2.02), while the mean delay from the first symptoms indicative of celiac disease to diagnosis was 2.2 years (SD ± 2.09). More than 70% of the patients were diagnosed in the first 7 years of life, mainly presented with gastrointestinal symptoms, while primary school children and adolescents mostly showed atypical symptoms (p<0.001). The classical form of celiac disease occurred in 78% of the cases. Sixty (95%) patients carried HLA-DQ2.5, DQ2.2 and/or HLA-DQ8 heterodimers, and only three of them tested negative. Conclusions: Kosovo, as the majority of developing countries, is still facing the classical form of celiac disease as the dominant mode of presentation; as a result, most children with other forms of the celiac disease remain undiagnosed. : Physicians should be aware of the wide range of clinical presentations and utilize low testing thresholds in order to prevent potential long-term problems associated with untreated celiac disease.


2020 ◽  
Vol 20 (1) ◽  
pp. 102-105 ◽  
Author(s):  
Hossein A. Rahdar ◽  
Mansoor Kodori ◽  
Mohamad R. Salehi ◽  
Mahsa Doomanlou ◽  
Morteza Karami-Zarandi ◽  
...  

Background: Brucellosis, a major health problem in developing countries, is a multisystem infection with a broad spectrum of clinical manifestations. Hematological complications, ranging from an intravascular coagulopathy to mild homeostasis disorders (such as gammopathy), have been reported in brucella infection. These signs and symptoms may lead to misdiagnosis of brucellosis with other hematological diseases. Case: A 65-year-old male whose occupation was shepherding was referred to our hospital as a known case of multiple myeloma with continuous fever, muscle weakness, and night sweating after taking 2 courses of chemotherapy. The laboratory diagnosis of multiple myeloma had been based on the observation of a high percent of plasma cells in the bone marrow aspiration. At follow- up, the result of patient's fever workup, with 2 sets of blood cultures, was positive for Brucella melitensis. Isolated brucella was confirmed as B. melitensis by 16S rRNA sequencing. Brucellosis serologic test was performed by agglutination test and positive results were obtained. The patient was discharged with the cessation of fever and general improvement after the end of the parental treatment phase of brucella bacteremia. Conclusions: Brucella infection may cause a severe disease, mimicking a primary hematological disease, which could complicate the correct diagnosis. In brucellosis cases, due to the wide range of symptoms, in addition to cultivation and serological methods, molecular methods should also be used to prevent inappropriate diagnosis and additional costs.


Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 497-501 ◽  
Author(s):  
C. D. Boyette ◽  
G. E. Templeton ◽  
R. J. Smith

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.


2021 ◽  
Vol 6 (58) ◽  
pp. eabg0833
Author(s):  
Bingyu Yan ◽  
Tilo Freiwald ◽  
Daniel Chauss ◽  
Luopin Wang ◽  
Erin West ◽  
...  

Patients with coronavirus disease 2019 (COVID-19) present a wide range of acute clinical manifestations affecting the lungs, liver, kidneys and gut. Angiotensin converting enzyme (ACE) 2, the best-characterized entry receptor for the disease-causing virus SARS-CoV-2, is highly expressed in the aforementioned tissues. However, the pathways that underlie the disease are still poorly understood. Here, we unexpectedly found that the complement system was one of the intracellular pathways most highly induced by SARS-CoV-2 infection in lung epithelial cells. Infection of respiratory epithelial cells with SARS-CoV-2 generated activated complement component C3a and could be blocked by a cell-permeable inhibitor of complement factor B (CFBi), indicating the presence of an inducible cell-intrinsic C3 convertase in respiratory epithelial cells. Within cells of the bronchoalveolar lavage of patients, distinct signatures of complement activation in myeloid, lymphoid and epithelial cells tracked with disease severity. Genes induced by SARS-CoV-2 and the drugs that could normalize these genes both implicated the interferon-JAK1/2-STAT1 signaling system and NF-κB as the main drivers of their expression. Ruxolitinib, a JAK1/2 inhibitor, normalized interferon signature genes and all complement gene transcripts induced by SARS-CoV-2 in lung epithelial cell lines, but did not affect NF-κB-regulated genes. Ruxolitinib, alone or in combination with the antiviral remdesivir, inhibited C3a protein produced by infected cells. Together, we postulate that combination therapy with JAK inhibitors and drugs that normalize NF-κB-signaling could potentially have clinical application for severe COVID-19.


2021 ◽  
Vol 10 (11) ◽  
pp. 2457
Author(s):  
Birgit J. Gerecke ◽  
Rolf Engberding

Noncompaction cardiomyopathy (NCCM) has gained increasing attention over the past twenty years, but in daily clinical practice NCCM is still rarely considered. So far, there are no generally accepted diagnostic criteria and some groups even refuse to acknowledge it as a distinct cardiomyopathy, and grade it as a variant of dilated cardiomyopathy or a morphological trait of different conditions. A wide range of morphological variants have been observed even in healthy persons, suggesting that pathologic remodeling and physiologic adaptation have to be differentiated in cases where this spongy myocardial pattern is encountered. Recent studies have uncovered numerous new pathogenetic and pathophysiologic aspects of this elusive cardiomyopathy, but a current summary and evaluation of clinical patient management are still lacking, especially to avoid mis- and overdiagnosis. Addressing this issue, this article provides an up to date overview of the current knowledge in classification, pathogenesis, pathophysiology, epidemiology, clinical manifestations and diagnostic evaluation, including genetic testing, treatment and prognosis of NCCM.


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