Targeting of a chlamydial protease impedes intracellular bacterial growth

Chlamydiae are obligate intracellular bacteria that propagate in a cytosolic vacuole. Recent work has shown that growth of Chlamydia induces the fragmentation of the Golgi apparatus (GA) into ministacks, which facilitates the acquisition of host lipids into the growing inclusion. GA fragmentation results from infection-associated cleavage of the integral GA protein, golgin-84. Golgin-84-cleavage, GA fragmentation and growth of Chlamydia trachomatis can be blocked by the peptide inhibitor WEHD-fmk. Here we identify the bacterial protease chlamydial protease-like activity factor (CPAF) as the factor mediating cleavage of golgin-84 and as the target of WEHD-fmk-inhibition. WEHD-fmk blocked cleavage of golgin-84 as well as cleavage of known CPAF targets during infection with C. trachomatis and C. pneumoniae. The same effect was seen when active CPAF was expressed in non-infected cells and in a cell-free system. Ectopic expression of active CPAF in non-infected cells was sufficient for GA fragmentation. GA fragmentation required the small GTPases Rab6 and Rab11 downstream of CPAF-activity. These results define CPAF as the first protein that is essential for replication of Chlamydia. We suggest that this role makes CPAF a potential anti-infective therapeutic target.     

Taxonomic clarification of the dinophyte Rhabdosphaera erinaceus Kamptner, ≡ Scrippsiella erinaceus comb. nov. (Thoracosphaeraceae,Peridiniales)

The Scrippsiella trochoidea species complex (Thoracosphaeraceae, Peridiniales) consists of a cryptic diversity and multiple species, for which established scientific names are not available at present. Previously, the name Scrippsiella trochoidea has been taxonomically clarified, leaving a reliable determination of morphologically similar, but only distantly related species impossible. We isolated and cultivated Scrippsiella erinaceus comb. nov. (strains GeoM*533 and GeoM*534) from material collected near the type locality off Rovinj, Republic of Croatia (Adriatic Sea). We barcoded the species of the Thoracosphaeraceae using rRNA sequences (including 22 new sequences) and investigated the morphology of the strains using light and electron microscopy. The Scrippsiella trochoidea species complex was composed of three primary clades, and the Adriatic strains were reliably assigned to one of them being distinct from the true Scrippsiella trochoidea. We designate an epitype for the basionym Rhabdosphaera erinaceus prepared from the strain GeoM*534. The unambiguous links between a scientific species name, its protologue, genetic characterization and spatial distribution have particular importance for character-poor, unicellular organisms such as the Dinophyceae.     

Trypanosoma cruzi Infection in Neotropical Wild Carnivores (Mammalia: Carnivora): At the Top of the T. cruzi Transmission Chain

Little is known on the role played by Neotropical wild carnivores in the Trypanosoma cruzi transmission cycles. We investigated T. cruzi infection in wild carnivores from three sites in Brazil through parasitological and serological tests. The seven carnivore species examined were infected by T. cruzi, but high parasitemias detectable by hemoculture were found only in two Procyonidae species. Genotyping by Mini-exon gene, PCR-RFLP (1f8/Akw21I) and kDNA genomic targets revealed that the raccoon (Procyon cancrivorus) harbored TcI and the coatis (Nasua nasua) harbored TcI, TcII, TcIII-IV and Trypanosoma rangeli, in single and mixed infections, besides four T. cruzi isolates that displayed odd band patterns in the Mini-exon assay. These findings corroborate the coati can be a bioaccumulator of T. cruzi Discrete Typing Units (DTU) and may act as a transmission hub, a connection point joining sylvatic transmission cycles within terrestrial and arboreal mammals and vectors. Also, the odd band patterns observed in coatis’ isolates reinforce that T. cruzi diversity might be much higher than currently acknowledged. Additionally, we assembled our data with T. cruzi infection on Neotropical carnivores’ literature records to provide a comprehensive analysis of the infection patterns among distinct carnivore species, especially considering their ecological traits and phylogeny. Altogether, fifteen Neotropical carnivore species were found naturally infected by T. cruzi. Species diet was associated with T. cruzi infection rates, supporting the hypothesis that predator-prey links are important mechanisms for T. cruzi maintenance and dispersion in the wild. Distinct T. cruzi infection patterns across carnivore species and study sites were notable. Musteloidea species consistently exhibit high parasitemias in different studies which indicate their high infectivity potential. Mesocarnivores that feed on both invertebrates and mammals, including the coati, a host that can be bioaccumulator of T. cruzi DTU’s, seem to take place at the top of the T. cruzi transmission chain.     

Derivation and Expansion Using Only Small Molecules of Human Neural Progenitors for Neurodegenerative Disease Modeling

Phenotypic drug discovery requires billions of cells for high-throughput screening (HTS) campaigns. Because up to several million different small molecules will be tested in a single HTS campaign, even small variability within the cell populations for screening could easily invalidate an entire campaign. Neurodegenerative assays are particularly challenging because neurons are post-mitotic and cannot be expanded for implementation in HTS. Therefore, HTS for neuroprotective compounds requires a cell type that is robustly expandable and able to differentiate into all of the neuronal subtypes involved in disease pathogenesis. Here, we report the derivation and propagation using only small molecules of human neural progenitor cells (small molecule neural precursor cells; smNPCs). smNPCs are robust, exhibit immortal expansion, and do not require cumbersome manual culture and selection steps. We demonstrate that smNPCs have the potential to clonally and efficiently differentiate into neural tube lineages, including motor neurons (MNs) and midbrain dopaminergic neurons (mDANs) as well as neural crest lineages, including peripheral neurons and mesenchymal cells. These properties are so far only matched by pluripotent stem cells. Finally, to demonstrate the usefulness of smNPCs we show that mDANs differentiated from smNPCs with LRRK2 G2019S are more susceptible to apoptosis in the presence of oxidative stress compared to wild-type. Therefore, smNPCs are a powerful biological tool with properties that are optimal for large-scale disease modeling, phenotypic screening, and studies of early human development.     

Bugging Forecast: Unknown,Disliked, Occasionally Intimate. Bed Bugs in Germany Meet Unprepared People

Bed bugs appear to be feared more than vector insects and other household pests. The reasons for this exaggerated fear are not fully understood. One hypothesis is that the folk knowledge on recognising and controlling bed bugs decreased as bed bugs became rarer in the 1960s and led to irrational perceptions. Here, we examine people’s ability to recognise a bed bug and their response what to do in case of an infestation. We found that 13% of a sample of 391 people in four large German cities recognised a bed bug; 15% of all respondents would call a pest controller in case of bed bug infestation. This results in the pessimistic estimate that 97% of all early-stage infestations could go untreated. We discuss additional scenarios. The effectiveness of efforts to educate people about the presence of bed bugs has never been tested, but our sample is useful to guide future studies. We found three sources of information were associated with increased recognition rates of bed bugs: a) previous contacts with bed bugs (60% recognition), b) knowledge from friends or relatives (25%) and school or education courses (15%). By contrast, people who heard of bed bugs from television, print media or the Internet showed reduced recognition rates. We propose that the former factors be tested for educational interventions. In Germany, the bed bug is an estranged creature to many people, a fact that seems to hinder rational approaches to their control.     

Relationships of Disability with Age Among Adults Aged 50 to 85: Evidence from the United States,England and Continental Europe

Objectives

To extend existing research on the US health disadvantage relative to Europe by studying the relationships of disability with age from midlife to old age in the US and four European regions (England/Northern and Western Europe/Southern Europe/Eastern Europe) including their wealth-related differences, using a flexible statistical approach to model the age-functions.

Methods

We used data from three studies on aging, with nationally representative samples of adults aged 50 to 85 from 15 countries (N = 48225): the US-American Health and Retirement Study (HRS), the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE). Outcomes were mobility limitations and limitations in instrumental activities of daily living. We applied fractional polynomials of age to determine best fitting functional forms for age on disability in each region, while controlling for socio-demographic characteristics and important risk factors (hypertension, diabetes, obesity, smoking, physical inactivity).

Results

Findings showed high levels of disability in the US with small age-related changes between 50 and 85. Levels of disability were generally lower in Eastern Europe, followed by England and Southern Europe and lowest in Northern and Western Europe. In these latter countries age-related increases of disability, though, were steeper than in the US, especially in Eastern and Southern Europe. For all countries and at all ages, disability levels were higher among adults with low wealth compared to those with high wealth, with largest wealth-related differences among those in early old age in the USA.

Conclusions

This paper illustrates considerable variations of disability and its relationship with age. It supports the hypothesis that less developed social policies and more pronounced socioeconomic inequalities are related to higher levels of disability and an earlier onset of disability.