A Screening Pipeline for Antiparasitic Agents Targeting Cryptosporidium Inosine Monophosphate Dehydrogenase

Persistent diarrhea is a leading cause of illness and death among impoverished children, and a growing share of this disease burden can be attributed to the parasite Cryptosporidium. There are no vaccines to prevent Cryptosporidium infection, and the treatment options are limited and unreliable. Critically, no effective treatment exists for children or adults suffering from AIDS. Cryptosporidium presents many technical obstacles for drug discovery; perhaps the most important roadblock is the difficulty of monitoring drug action. Here we have developed a set of methods to accelerate the drug discovery process for cryptosporidiosis. We exploit the opportunities for experimental manipulation in the related parasite Toxoplasma to genetically engineer a Cryptosporidium model. This new model parasite mirrors the metabolism of Cryptosporidium for a particularly promising drug target that supplies the building blocks for DNA and RNA. Drug effectiveness can be assayed through simple fluorescence measurements for many candidates. Using this assay as an initial filter, and adapting other assays to a high throughput format, we identify several novel chemical compounds that exhibit markedly improved anti-cryptosporidial activity and excellent selectivity

ALL IS NOT FAIR IN THE APPRAISALS OF PERFORMANCE: APPRAISALS , JUSTICE , AND WORK OUTCOMES

This study examined the moderating effect of core self-evaluation (CSE) on the relationship between perceptions of procedural performance appraisal justice (PAJ) and the components of engagement (vigor , dedication , and absorption) and burnout (emotional exhaustion , professional inefficacy , and cynicism). Both procedural PAJ and CSE significantly predicted all components of engagement and burnout. Specifically , higher levels of PAJ and CSE predicted higher engagement and lower burnout. Moreover , CSE significantly moderated the relationship between procedural PAJ and absorption such that high CSE individuals were less affected by procedural performance appraisal justice compared to that of low CSE individuals. Overall , the findings suggest two things: (1) having more procedurally just performance appraisal processes and high CSE employees should lead to more engaged and less burned out employees and (2) higher levels of core self-evaluation may play a critical mitigating role in the relationship between procedural PAJ perceptions and absorption

ALL IS NOT FAIR IN THE APPRAISALS OF PERFORMANCE: APPRAISALS, JUSTICE, AND WORK OUTCOMES

This study examined the moderating effect of core self-evaluation (CSE) on the relationship between perceptions of procedural performance appraisal justice (PAJ) and the components of engagement (vigor, dedication, and absorption) and burnout (emotional exhaustion, professional inefficacy, and cynicism). Both procedural PAJ and CSE significantly predicted all components of engagement and burnout. Specifically, higher levels of PAJ and CSE predicted higher engagement and lower burnout. Moreover, CSE significantly moderated the relationship between procedural PAJ and absorption such that high CSE individuals were less affected by procedural performance appraisal justice compared to that of low CSE individuals. Overall, the findings suggest two things: (1) having more procedurally just performance appraisal processes and high CSE employees should lead to more engaged and less burned out employees and (2) higher levels of core self-evaluation may play a critical mitigating role in the relationship between procedural PAJ perceptions and absorption

Stable nuclear transformation of Eudorina elegans

Lerche K, Hallmann A. Stable nuclear transformation of Eudorina elegans. BMC Biotechnology. 2013;13(1): 11.UNLABELLED: ABSTRACT: BACKGROUND: A fundamental step in evolution was the transition from unicellular to differentiated, multicellular organisms. Volvocine algae have been used for several decades as a model lineage to investigate the evolutionary aspects of multicellularity and cellular differentiation. There are two well-studied volvocine species, a unicellular alga (Chlamydomonas reinhardtii) and a multicellular alga with differentiated cell types (Volvox carteri). Species with intermediate characteristics also exist, which blur the boundaries between unicellularity and differentiated multicellularity. These species include the globular alga Eudorina elegans, which is composed of 16-32 cells. However, detailed molecular analyses of E. elegans require genetic manipulation. Unfortunately, genetic engineering has not yet been established for Eudorina, and only limited DNA and/or protein sequence information is available. RESULTS: Here, we describe the stable nuclear transformation of E. elegans by particle bombardment using both a chimeric selectable marker and reporter genes from different heterologous sources. Transgenic algae resistant to paromomycin were achieved using the aminoglycoside 3'-phosphotransferase VIII (aphVIII) gene of Streptomyces rimosus, an actinobacterium, under the control of an artificial promoter consisting of two V. carteri promoters in tandem. Transformants exhibited an increase in resistance to paromomycin by up to 333-fold. Co-transformation with non-selectable plasmids was achieved with a rate of 50 - 100%. The luciferase (gluc) gene from the marine copepod Gaussia princeps, which previously was engineered to match the codon usage of C. reinhardtii, was used as a reporter gene. The expression of gluc was mediated by promoters from C. reinhardtii and V. carteri. Heterologous heat shock promoters induced an increase in luciferase activity (up to 600-fold) at elevated temperatures. Long-term stability and both constitutive and inducible expression of the co-bombarded gluc gene was demonstrated by transcription analysis and bioluminescence assays. CONCLUSIONS: Heterologous flanking sequences, including promoters, work in E. elegans and permit both constitutive and inducible expression of heterologous genes. Stable nuclear transformation of E. elegans is now routine. Thus, we show that genetic engineering of a species is possible even without the resources of endogenous genes and promoters

Size-strain line-broadening analysis of a ceria round-robin sample

International audienc

Size-strain line-broadening analysis of a ceria round-robin sample

International audienc