UV irradiation responses in Giardia intestinalis

Giardia duodenalis

“…The capability of Giardia cysts to repair UVmediated DNA damage and maintain infectivity has also been investigated. A recent study showed that UV treatment did not actually kill the cell but damaged its DNA, in agreement with the hypothesis that the replication machinery is important for survival of Giardia (Einarsson et al, 2015). Indeed, mature cysts might not have had an active replication machinery at the time of irradiation, and are therefore unable to detect and repair the DNA lesions.…”

“…Higher UV doses (between 20 and 40 mJ/cm 2 ) resulted in up to 3 log 10 inactivation of the cysts. The most recent study indicates that cysts could not survive irradiation doses higher than 5 mJ/cm 2 (Einarsson et al, 2015). Cysts exposed even to the lowest dose (1 mJ/cm 2 ) of medium pressure (MP) UV irradiation failed to establish an infection in gerbils (Shin et al, 2010).…”

Characterization of recombinase DMC1B and its functional role as Rad51 in DNA damage repair in Giardia duodenalis trophozoites

“…Additionally, in transcriptomics studies performed on trophozoites exposed to ultraviolet light (UV) and after 3 h of recovery, the transcript levels for GdDMC1B were higher than those of GdDMC1A, and conversely, when cysts were UV treated, GdDMC1A-specific transcripts were higher than those of GdDMC1B. However, none of these changes were statistically significant [49]. In contrast, our study demonstrated a statistically significant increase in GdDMC1B transcripts and protein upon ionizing radiation DNA damage, probably due to its severity compared to UV treatment.…”

The Effects of Concomitant Giardia intestinalis Infection on Acute Gastrointestinal Toxicity in Rats Undergoing Pelvic Irradiation

“…The reaction to the radiation of ultraviolet light (UV) is considered to be a characteristic stressor to the intestinal protozoan parasite Giardia intestinalis (14). Reactive oxygen species (ROS), which may alter the structure of membrane and proteins, can be generated as a result of UV radiation of cells (34).…”

“…Both humans and livestock are infected by this parasite. Furthermore, it is believed that some genetic variants of Giardia intestinalis have zoonotic potential (14). This parasite, which is considered to be the main reason for protozoan diarrhea, is encountered around the world.…”