Biology and field host range of Ceutorhynchus cardariae,a potential biological control agent for Lepidium draba

Lepidium draba (Brassicaceae) is a clonal herb, originating from Eurasia, which is invasive in North America. A classical biological control project was initiated in 2001, and the gall‐forming weevil Ceutorhynchus cardariae was prioritized as a candidate agent. We studied its biology and field host range between 2003 and 2014 in the laboratory and a common garden in Switzerland and in the field in Romania. Ceutorhynchus cardariae is a univoltine to bivoltine species. In Switzerland, oviposition usually started at the beginning of March and can occur at temperatures as low as 2.5°C. Galls are formed on stems, leaf stalks and midribs of L. draba rosettes and bolting plants. Gall size increased with an increasing number of larvae per gall. The three larval instars feed inside the galls and leave the plant to pupate in the soil once mature. In Switzerland, development from egg to adult took about 12 weeks in spring. Adults emerged from May to July. After a brief feeding period, adults aestivate. From late summer, feeding recommenced and females may oviposit, forming a partial second generation. Eggs and all larval instars can be found in galls throughout winter. The rate of larval ectoparasitism reached 78%, while endoparasitism was low with a maximum of 2.3%. Lepidium draba populations differed in their suitability for development (number of C. cardariae produced), indicating that effectiveness of C. cardariae – in case released – may be variable. In the field, we observed that gall formation by C. cardariae can severely stunt or even kill shoots. Investigations on the field host range of C. cardariae indicated that only the closely related Lepidium campestre may act as an alternative host for the weevil in Europe. Host‐specificity tests are underway to determine its environmental safety before field release in North America is being considered.     

Bacterial protein HU dictates the morphology of DNA condensates produced by crowding agents and polyamines

Controlling the size and shape of DNA condensates is important in vivo and for the improvement of nonviral gene delivery. Here, we demonstrate that the morphology of DNA condensates, formed under a variety of conditions, is shifted completely from toroids to rods if the bacterial protein HU is present during condensation. HU is a non-sequence-specific DNA binding protein that sharply bends DNA, but alone does not condense DNA into densely packed particles. Less than one HU dimer per 225 bp of DNA is sufficient to completely control condensate morphology when DNA is condensed by spermidine. We propose that rods are favored in the presence of HU because rods contain sharply bent DNA, whereas toroids contain only smoothly bent DNA. The results presented illustrate the utility of naturally derived proteins for controlling the shape of DNA condensates formed in vitro. HU is a highly conserved protein in bacteria that is implicated in the compaction and shaping of nucleoid structure. However, the exact role of HU in chromosome compaction is not well understood. Our demonstration that HU governs DNA condensation in vitro also suggests a mechanism by which HU could act as an architectural protein for bacterial chromosome compaction and organization in vivo.     

Consent for participating in clinical trials ‐ Is it really informed?

The article explores the challenges of ensuring voluntary and informed consent which is obtained from potential research subjects in the north‐eastern part of Romania. This study is one of the first empirical papers of this nature in Romania. The study used a quantitative survey design using the adapted Quality of Informed Consent (QuIC) questionnaire. The target population consisted of 100 adult persons who voluntarily enrolled in clinical trials. The informed consent form must contain details regarding the potential risks and benefits, the aim of the clinical trial, study design, confidentiality, insurance and contact details in case of additional questions. Our study confirmed that although all required information was included in the ICF, few clinical trial participants truly understood it. We also found that the most important predictive factor for a good subjective and objective understanding of the clinical trial was the level of education. Our study suggests that researchers should consider putting more effort in order to help clinical trials participants achieve a better understanding of the informed consent. In this way they will ensure that participants’ decision‐making is meaningful and that their interests are protected.     

A dominant role for Fc gamma receptors in antibody-dependent corneal inflammation.

Although production of specific Ab is a critical element of host defense, the presence of Ab in tissues leads to formation of immune complexes, which can trigger a type III Arthus reaction. Our studies on a mouse model of river blindness showed that Ab production is essential for recruitment of neutrophils and eosinophils to the cornea and for development of corneal opacification. In the current study, we determined the relative contribution of complement and FcgammaR interactions in triggering immune complex-mediated corneal disease. FcgammaR(-/-) mice, C3(-/-) mice, and immunocompetent control (B6/129Sj) mice were immunized s.c. and injected intrastromally with Onchocerca volvulus Ags. Slit lamp examination showed that control mice, C3(-/-) mice, and control mice injected with cobra venom factor developed pronounced corneal opacification, whereas corneas of FcgammaR(-/-) mice remained completely clear. Furthermore, recruitment of neutrophils and eosinophils to the corneal stroma was significantly impaired in FcgammaR(-/-) mice, but not in C3(-/-) mice or cobra venom factor-treated mice. We therefore conclude that FcgammaR-mediated cell activation, rather than complement activation, is the dominant pathway of immune complex disease in the cornea. These findings demonstrate a novel role for FcgammaR interactions in mediating ocular inflammation.     

Divergence and Remarkable Diversity of the Y Chromosome in Guppies

The guppy sex chromosomes show an extraordinary diversity in divergence across populations and closely related species. In order to understand the dynamics of the guppy Y chromosome, we used linked-read sequencing to assess Y chromosome evolution and diversity across upstream and downstream population pairs that vary in predator and food abundance in three replicate watersheds. Based on our population-specific genome assemblies, we first confirmed and extended earlier reports of two strata on the guppy sex chromosomes. Stratum I shows significant accumulation of male-specific sequence, consistent with Y divergence, and predates the colonization of Trinidad. In contrast, Stratum II shows divergence from the X, but no Y-specific sequence, and this divergence is greater in three replicate upstream populations compared with their downstream pair. Despite longstanding assumptions that sex chromosome recombination suppression is achieved through inversions, we find no evidence of inversions associated with either Stratum I or Stratum II. Instead, we observe a remarkable diversity in Y chromosome haplotypes within each population, even in the ancestral Stratum I. This diversity is likely due to gradual mechanisms of recombination suppression, which, unlike an inversion, allow for the maintenance of multiple haplotypes. In addition, we show that this Y diversity is dominated by low-frequency haplotypes segregating in the population, suggesting a link between haplotype diversity and female preference for rare Y-linked color variation. Our results reveal the complex interplay between recombination suppression and Y chromosome divergence at the earliest stages of sex chromosome divergence.     

Defects in innate immunity render breast cancer initiating cells permissive to oncolytic adenovirus

Background

Cancer stem cells/initiating cells (CSC/CIC), are thought to exist as a small population in malignant tissues. They are resistant to conventional cancer treatments and possibly underlie post-treatment relapse. The CIC population can be targeted with capsid modified oncolytic adenoviruses.

Methodology/Principal Findings

We studied the mechanisms of innate immunity to oncolytic adenovirus Ad5/3-Delta24 in conventional treatment resistant non-CIC breast cancer cells, breast cancer CD44⁺/CD24^−/low CIC population and normal breast tissue CD44⁺/CD24^−/low stem cells. We compared virus recognition by pattern recognition receptors for adenovirus, Toll-like receptors (TLR) 2 and 9 and virus induced type I interferon (IFN) response regulation in these cell types. We show TLR mediated virus recognition in these non-immune cell types. Normal tissue stem cells have intact type I IFN signaling. Furthermore, TLR9 and TLR2 reside constantly in recognition sites, implying constant activation. In contrast, breast cancer CD44⁺/CD24^−/low CIC have dysregulated innate immune responses featuring dysfunctional virus recognition caused by impaired trafficking of TLR9 and cofactor MyD88 and the absence of TLR2, having a deleterious impact on TLR pattern recognition receptor signaling. Furthermore, the CIC have increased inhibitory signaling via the suppressor of cytokine signaling/Tyro3/Axl/Mer receptor tyrosine kinase (SOCS/TAM) pathway. These defects in contribute to dysfunctional induction of type I IFN response in CIC and therefore permissivity to oncolytic adenovirus.

Conclusions/Significance

CICs may underlie the incurable nature of relapsed or metastatic cancers and are therefore an important target regarding diagnostic and prognostic aspects as well as treatment of the disease. This study addresses the mechanisms of innate infection immunity in stem cells deepening the understanding of stem cell biology and may benefit not only virotherapy but also immunotherapy in general.     

Towards the Development of Hemerythrin-Based Blood Substitutes

Hemerythrin is proposed as an alternative to hemoglobin-based blood substitutes. In contrast to hemoglobin, hemerythrin exhibits negligible reactivity towards oxidative and nitrosative stress agents (peroxide, nitric oxide, nitrite). Protocols for attachment of polyethylene glycol and glutaraldehyde cross-linking of Hr are described. These derivatizations appear to have favorable effects on O₂ affinity and autoxidation rates for use in blood substitutes. Based on lessons learned from hemoglobin-based blood substitutes, these derivatizations should also help limit extravasation and antigenicity of a hemerythrin-based blood substitute.