Translational Control of UIS4 Protein of the Host-Parasite Interface Is Mediated by the RNA Binding Protein Puf2 in Plasmodium berghei Sporozoites

UIS4 is a key protein component of the host-parasite interface in the liver stage of the rodent malaria parasite Plasmodium berghei and required for parasite survival after invasion. In the infectious sporozoite, UIS4 protein has variably been shown to be translated but also been reported to be translationally repressed. Here we show that uis4 mRNA translation is regulated by the P. berghei RNA binding protein Pumilio-2 (PbPuf2 or Puf2 from here on forward) in infectious salivary gland sporozoites in the mosquito vector. Using RNA immunoprecipitation we show that uis4 mRNA is bound by Puf2 in salivary gland sporozoites. In the absence of Puf2, uis4 mRNA translation is de-regulated and UIS4 protein expression upregulated in salivary gland sporozoites. Here, using RNA immunoprecipitation, we reveal the first Puf2-regulated mRNA in this parasite.     

Dialysis-Requiring Acute Kidney Injury in Denmark 2000-2012: Time Trends of Incidence and Prevalence of Risk Factors—A Nationwide Study

Introduction

Dialysis-requiring acute kidney injury is a severe illness associated with poor prognosis. However, information pertaining to incidence rates and prevalence of risk factors remains limited in spite of increasing focus. We evaluate time trends of incidence rates and changing patterns in prevalence of comorbidities, concurrent medication, and other risk factors in nationwide retrospective cohort study.

Materials and Methods

All patients with dialysis-requiring acute kidney injury were identified between January 1^st 2000 and December 31^st 2012. By cross-referencing data from national administrative registries, the association of changing patterns in dialysis treatment, comorbidity, concurrent medication and demographics with incidence of dialysis-requiring acute kidney injury was evaluated.

Results

A total of 18,561 adult patients with dialysis-requiring AKI were identified between 2000 and 2012. Crude incidence rate of dialysis-requiring AKI increased from 143 per million (95% confidence interval, 137–144) in 2000 to 366 per million (357–375) in 2006, and remained stable hereafter. Notably, incidence of continuous veno-venous hemodialysis (CRRT) and use of acute renal replacement therapy in elderly >75 years increased substantially from 23 per million (20–26) and 328 per million (300–355) in 2000, to 213 per million (206–220) and 1124 per million (1076–1172) in 2012, respectively. Simultaneously, patient characteristics and demographics shifted towards increased age and comorbidity.

Conclusions

Although growth in crude incidence rate of dialysis-requiring AKI stabilized in 2006, continuous growth in use of CRRT, and acute renal replacement therapy of elderly patients >75 years, was observed. Our results indicate an underlying shift in clinical paradigm, as opposed to unadulterated growth in incidence of dialysis-requiring AKI.     

Systematics and origin of moths in the subfamily Arctiinae (Lepidoptera,Erebidae) in the Neotropical region

The availability of standard protocols to obtain DNA sequences has allowed the inference of phylogenetic Hypotheses for many taxa, including moths. We here have inferred a phylogeny using maximum‐Likelihood and Bayesian approaches for a species‐rich group of moths (Erebidae, Arctiinae), with strong emphasis on Neotropical genera collected in different field campaigns in the Atlantic Forest of Brazil, eastern Amazon and southern Ecuador. A total of 277 species belonging to 246 genera were included in the analysis. Our main objectives were to shed light on the relationships between suprageneric groups, especially subtribes, and hypothesize colonization events in and out of the Neotropics. The monophyly of Arctiinae and its four tribes (Lithosiini, Amerilini, Syntomini and Arctiini) was recovered in the ML and Bayesian trees. Three Lithosiini subtribes previously found and two additional species groups were recovered monophyletic in both phylogenetic estimation methods. In Arctiini, the monophyly of Spilosomina and Arctiina was highly supported in the ML and Bayesian trees, but the monophyly of Ctenuchina and Echromiina was weakly supported in the ML tree and absent in the Bayesian tree; the remaining subtribes were paraphyletic and, in the case of Phageopterina, formed several species groups. The mapping of species occurrence in our ML tree suggests that Arctiinae have an Old World origin and that the Neotropical region was colonized at least six times independently. Our analysis also suggests that a number of species that occur in Neotropical and other zoogeographic regions may have originated in the Neotropics, although further taxon sampling is required to support this hypothesis. To our knowledge, this is the first time that a highly speciose group of tropical moths is well covered in a phylogeny, and it seems plausible that the results reported here may be extendable to other species‐rich tropical undersampled moth taxa.     

Interpretation of Data Obtained with Recombination-Defective Meiotic Mutants

Gene frequency distributions observed in large-scale surveys of species of Drosophila are shown to be incompatible with a genetic model involving neutral mutations and genetic drift alone. The data are, however, qualitatively similar to predictions based on an alternative model of natural selection for an optimal level of enzyme activity in addition to drift and mutation. The intensity of selection detected reduces the mean rate of gene substitution to less than one-quarter that expected on the neutral-allele hypothesis.     

Minichromosomes inDrosophila melanogaster derived from the transposing elementTE1

A minichromosome has originated from the transposing elementTE1. This autonomously replicating chromosome contains the structural genes white and roughest, from theDrosophila X chromosome. It arose within a stock carryingTE1 at 45F on chromosome2. In addition to thew andrst genes, the minichromosome may carry section 45C–45F from chromosome2. It is inherited by 33%–47% of the offspring. By this criterion it carries a centromere, although the origin of the centromere is unknown. From this minichromosome a still smaller one has originated, probably through the loss of all material from chromosome2 together with some heterochromatin. At the same time a duplication of white and roughest could have taken place. This chromosome has a strange morphology and is more frequently lost in meiosis than the larger one, but is still transmitted to about 29%–37% of the progeny of one parent heterozygous for the minichromosome. In both cases the flies have variegated eyes, probably as a result of position-effect variegation. The variegation pattern is influenced by factors in theX chromosome. The size of the smaller minichromosome is little more than 1 Mb as determined by pulsed field gel electrophoresis.     

Fly disturbance suppresses aphid population growth

1. The presence of predators is known to suppress prey populations not only by consumptive but also by non-consumptive effects, as it stresses the prey inducing costly changes to behaviour and physiology. However, there is recent evidence that disturbance from non-predacious, non-competing commensals can also negatively affect herbivore performance. 2. Populations of cherry-oat aphids (Rhopalosiphum padi L.) were initiated with adult aphids in mesocosms containing seedling wheat grass. Following aphid establishment, fruit flies (Drosophila melanogaster Meigen) were added at a relatively high density to half of the mesocosms and the aphids were left for another 5 days to reproduce. The experiment was performed over two blocks at 24 ± 4 °C. It was hypothesized that a relatively high density of commensals would stress the aphids and reduce their fitness, causing lower population growth and resulting in lower population sizes. 3. Aphid numbers were significantly lower in mesocosms with commensal flies after 5 days of fly presence across the two experimental blocks, documenting that fly disturbance suppresses aphid fitness and population growth. 4. The negative effect of fruit flies on aphid population growth must have come from the disturbance that flies imposed on the aphids in their search for food, indicating that the flies stressed the aphids. Thus, our study indicates that commensals may stress herbivores that do not distinguish between enemies and other active species in their environment, adding in the overall herbivore top-down control through fitness costs.