Redundancy, phylogeny and differential expression of Histoplasma capsulatum catalases.
نویسندگان
چکیده
Histoplasma capsulatum produces an extracellular catalase termed M antigen, which is similar to catalase B of Aspergillus and Emericella species. Evidence is presented here for two additional catalase isozymes in H. capsulatum. Catalase A is highly similar to a large-subunit catalase in Aspergillus and Emericella species, while catalase P is a small-subunit catalase protein with greatest similarity to known peroxisomal catalases of animals and Saccharomycotina yeasts. Complete cDNAs for the CATA and CATP genes (encoding catalases A and P, respectively) were isolated. The transcriptional expression of the H. capsulatum CATA, CATB (M antigen) and CATP genes was assessed by Northern blot hybridizations on total RNA. Results at the transcript levels for these genes are shown for three conditions: cell morphology (mycelial versus yeast phase cells), oxidative stress (in response to a challenge with H(2)O(2)) and carbon source (glucose vs glycerol). Collectively, these results demonstrated regulation of CATA by both cell morphology and oxidative stress, but not by carbon source, and regulation of CATB and CATP by carbon source but not cell morphology or oxidative stress. A phylogenetic analysis of presently available catalase sequences and intron residences was done. The results support a model for evolution of eukaryotic monofunctional catalase genes from prokaryotic genes.
منابع مشابه
Redundant catalases detoxify phagocyte reactive oxygen and facilitate Histoplasma capsulatum pathogenesis.
Histoplasma capsulatum is a respiratory pathogen that infects phagocytic cells. The mechanisms allowing Histoplasma to overcome toxic reactive oxygen molecules produced by the innate immune system are an integral part of Histoplasma's ability to survive during infection. To probe the contribution of Histoplasma catalases in oxidative stress defense, we created and analyzed the virulence defects...
متن کاملPCR assay for identification of histoplasma capsulatum based on the nucleotide sequence of the M antigen.
The major diagnostic antigens of Histoplasma capsulatum var. capsulatum are the H and M antigens, pluripotent glycoproteins that elicit both humoral and T-cell-mediated immune responses. The gene encoding the M antigen has previously been sequenced, and its sequence has significant overall homology to those of the genes for fungal catalases. Regions of the M-antigen gene with little or no homol...
متن کاملBiological Function and Molecular Mapping of M Antigen in Yeast Phase of Histoplasma capsulatum
Histoplasmosis, due to the intracellular fungus Histoplasma capsulatum, can be diagnosed by demonstrating the presence of antibodies specific to the immunodominant M antigen. However, the role of this protein in the pathogenesis of histoplasmosis has not been elucidated. We sought to structurally and immunologically characterize the protein, determine yeast cell surface expression, and confirm ...
متن کاملMolecular cloning, characterization, and expression of the M antigen of Histoplasma capsulatum.
The major diagnostic antigens of Histoplasma capsulatum are the H and M antigens, pluripotent glycoproteins that elicit both humoral and T-cell-mediated immune responses. These antigens may play a role in the pathogenesis of histoplasmosis. M antigen is considered immunodominant because antibodies against it are the first precipitins to arise in acute histoplasmosis and are commonly present dur...
متن کاملCranial and Spinal Locations of Histoplasma capsulatum var. duboisii in Brazzaville
Background: Histoplasma capsulatum var. duboisii is a rare fungus, endemic in southern Africa of the Sahara and Madagascar. Objective: To describe the confirmed cases of histoplasmosis. Methods: This retrospective study was conducted at the division of neurosurgery of Brazzaville academic hospital in the Republic of Congo. Clinical records of all confirmed cases who were admitted between Jan...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Microbiology
دوره 148 Pt 4 شماره
صفحات -
تاریخ انتشار 2002