Proteomic Analysis of Trypanosoma cruzi Response to Ionizing Radiation Stress

Abstract

Trypanosoma cruzi, the causative agent of Chagas disease, is extremely resistant to ionizing radiation, enduring up to 1.5 kGy of gamma rays. Ionizing radiation can damage the DNA molecule both directly, resulting in double-strand breaks, and indirectly, as a consequence of reactive oxygen species production. After a dose of 500 Gy of gamma rays, the parasite genome is fragmented, but the chromosomal bands are restored within 48 hours. Under such conditions, cell growth arrests for up to 120 hours and the parasites resume normal growth after this period. To better understand the parasite response to ionizing radiation, we analyzed the proteome of irradiated (4, 24, and 96 hours after irradiation) and non-irradiated T. cruzi using two-dimensional differential gel electrophoresis followed by mass spectrometry for protein identification. A total of 543 spots were found to be differentially expressed, from which 215 were identified. These identified protein spots represent different isoforms of only 53 proteins. We observed a tendency for overexpression of proteins with molecular weights below predicted, indicating that these may be processed, yielding shorter polypeptides. The presence of shorter protein isoforms after irradiation suggests the occurrence of post-translational modifications and/or processing in response to gamma radiation stress. Our results also indicate that active translation is essential for the recovery of parasites from ionizing radiation damage. This study therefore reveals the peculiar response of T. cruzi to ionizing radiation, raising questions about how this organism can change its protein expression to survive such a harmful stress.

The recombinase Rad51 plays a key role in events of genetic exchange in Trypanosoma cruzi

“…As shown in Fig. 1 , all three strains presented a stationary phase following irradiation; however, unlike CL Brener epimastigotes, which resumed their cellular growth after 10 days as previously described 34 – 36 , Sylvio and Esmeraldo epimastigotes exhibited longer stationary phases as their cellular growth resumed only 15 days after exposure to ionizing radiation, showing that CL Brener cells present decreased cellular growth arrest in response to genotoxicity. The same growth recovery pattern was observed when other naturally-occurring hybrid strain Bug2149 cl10 (TcV), and non-hybrid strains Dm28c (TcI) and Y (TcII) were analyzed ( S1 Fig.…”

“…As previously presented, after being exposed to moderate doses of ionizing radiation, T. cruzi epimastigotes exhibit a lag phase, and resume their cellular growth several days after irradiation, being this lag phase shorter when parasites are naturally-occurring hybrids (Fig. 2A ) 34 – 36 . We then finally investigated if fused-cell hybrids would be able to resume their cellular growth, after exposure to ionizing radiation, earlier than non-fused cells.…”

“…In addition, HR is the most important pathway for T. cruzi to cope with DNA double-strand breaks (DSBs) as essential proteins for the non-homologous end joining pathway have not been identified in the genome of this organism 32 . Interestingly, T. cruzi presents a high resistance against ionizing radiation, a genotoxic agent which is an important source of DSBs 33 , 34 this peculiar phenotype most certainly a consequence of an efficient HR DNA repair pathway 34 – 36 . One important protein involved in this pathway is the recombinase Rad51, whose role is to search for homology during the DNA repair process 37 .…”

The Predicted ABC Transporter AbcEDCBA Is Required for Type IV Secretion System Expression and Lysosomal Evasion by Brucella ovis

“…Differentially expressed spots between WT and Δ abcBA B. ovis were excised from gel, treated with trypsin, and desalted using Zip-Tips (Millipore Corporation), as described elsewhere [34] . Each sample was mixed with 0.5 vol of saturated matrix solution (10 mg/mL α-cyano-4-hydroxycinnamic acid in 50% acetonitrile/0.1% trifluoroacetic acid).…”

Evaluation of the effect of radioactive cobalt-60 and ultraviolet rays on Giardia lamblia infectivity to mice

“…Since the early nineties, cobalt-60, a type of gamma radiation, has been used on food to control infectivity of several parasites as Paragonimus westermani [13] , Metagonimus yokogawai [14] , Eimeria tenella [15] , Toxoplasma gondii [16] , Angiostrongylus cantonensis [17] , Taenia solium [18] , Clonorchis sinensis [19] , Cryptosporidium parvum [20] , Ascaris lumbricoides [21] , Trypanosoma cruzi [22] and Echinococcus granulosus [23] . UV irradiation usage for the disinfection of drinking water was first applied in 1910 in Marseille.…”