An early signaling transcription factor regulates differentiation in Giardia

Transcriptional regulation of differentiation is critical for parasitic pathogens to adapt to environmental changes and regulate transmission. How early signaling transcription factors (TF) activate signal transduction to initiate encystation remains an open question in Giardia. Here, we generate a CasRX-mediated knockdown system, together with an established CRISPRi system to screen early signaling TFs in Giardia lamblia. We identified an early response TF, GARP4 that regulates cyst wall protein (CWP) levels during encystation. Depletion of GARP4 increases encystation efficiency resulting in increased cyst production. Interestingly, cyst viability and CWP1 trafficking are not altered in GARP4 knockdowns, suggesting GARP4 regulates the restriction point controlling the portion of cells that terminally differentiate into cysts. Consistent with previous studies, we find that stimulation of encystation shifts the distribution of cells to the G2/M phase and these cells exhibits higher levels of CWP1, indication that entry into the encystation pathway is cell cycle regulated. Key to this increase of CWP1 in G2/M cells is activation of MYB2, a TF commonly observed during the early phase of encystation in Giardia. Remarkably, activated GARP4 only exhibits in G1/S cells, suggesting it has a role in preventing encystation until G2/M. Furthermore, we demonstrate that depletion of GARP4 activates MYB2 and overexpression of GARP4 represses MYB2. Our findings provide the first molecular mechanism underlying the restriction point regulating differentiation during early signaling of encystation in Giardia lamblia.

Cyst Viability and Economic Significance of Hydatidosis in Southern Ethiopia

Hydatidosis is cystic parasitosis caused by a larval stage of Echinococcus granulosus with immense economic and public health significance. A cross-sectional study was conducted from November 2016 to April 2017 in the city municipal abattoir of Southern Ethiopia with the aim of determining prevalence and cyst fertility and estimating financial losses associated with organ condemnation. The visceral organs of about 400 cattle were examined for hydatid cysts after slaughter. Postmortem examination, cyst characterization, and direct financial loss estimations were carried out. From the total 400 cattle examined, 208 (52%) were found positive for hydatid cyst infection in one or more of their organs. A total of about 395 hydatid cysts were collected from different organs of the infected cattle. Anatomical distribution of the cysts indicated that around 245 (62.03 %) were found in lung, 91 (23.04%) in liver, 26 (6.58%) in heart, 21 (5.32%) in spleen, and 12(3.04%) in kidney. From the total 395 cysts collected, 166 (42.03%) were found fertile and 229 (57.97%) nonfertile. From the total fertile cysts, 70 (42.17%) were found to be viable and 96 (57.83%) nonviable. Furthermore, from the total nonfertile cysts, 204 (89.08%) and 25 (10.91%) were sterile and calcified, respectively. Distribution of cyst calcification was higher in liver and fertility rate was higher in the cysts of lungs. The statistical analysis showed that the prevalence of hydatidosis was found to be significantly associated with age of the studied animals (P<0.05). However, there was no significant association (P>0.05) between the prevalence of bovine hydatidosis and other risk factors such as sex, breed, body condition, and origin of animals. The annual financial loss calculated from organ condemnation was estimated about 58,114.62 USD. This study revealed that hydatidosis is a highly prevalent disease in the study area with a huge economic losses. Therefore, there is a need for immediate intervention by breaking the life cycle of the parasite to alleviate its economic impact and zoonotic risks to humans.

The Effect of chlorine on giardia cyst destruction isolated from different water sources in Maysan province

<p>G. lamblia was a binucleate flagellated protozoan parasite that infected the upper intestinal tract of human and many animal species. Giardiasis was the most frequently diagnosed water borne disease and the major public health concern of water utilities in the developed and developing nations. Water is an important vehicle for the transmission of Giardia to human and mammals. For identified the effect of chlorine on Giardia cyst. To detect viability of cyst in different chlorine concentration. To determine the threshold level of chlorine concentration that caused cyst destruction. Measure the pH, chlorine concentration, filtration processes and examined by zinc sulfate centrifugal flotation technique using. 50% of samples contain Giardia cysts which are untreated water sources. Cyst viability differs in different chlorine concentration in different period of time extend from few hours to more than twenty days. The extreme chlorine concentration which caused cyst destruction in hours is 1.5 mg/L.</p>