Behavioural effects of juvenile hormone and their influence on division of labour in leaf-cutting ant societies

Division of labour in social insects represents a major evolutionary transition, but the physiological mechanisms that regulate this are still little understood. Experimental work with honey bees, and correlational analyses in other social insects, have implicated juvenile hormone (JH) as a regulatory factor, but direct experimental evidence of behavioural effects of JH in social insects is generally lacking. Here, we used experimental manipulation of JH to show that raised JH levels in leaf-cutting ants results in workers becoming more active, phototactic and threat responsive, and engaging in more extranidal activity – behavioural changes that we show are all characteristic of the transition from intranidal work to foraging. These behavioural effects on division of labour suggest that the JH mediation of behaviour occurs across multiple independent evolutions of eusociality, and may be a key endocrine regulator of the division of labour which has produced the remarkable ecological and evolutionary success of social insects

Drift-dependent changes in iceberg size-frequency distributions

Although the size-frequency distributions of icebergs can provide insight into how they disintegrate, our understanding of this process is incomplete. Fundamentally, there is a discrepancy between iceberg power-law size-frequency distributions observed at glacial calving fronts and lognormal size-frequency distributions observed globally within open waters that remains unexplained. Here we use passive seismic monitoring to examine mechanisms of iceberg disintegration as a function of drift. Our results indicate that the shift in the size-frequency distribution of iceberg sizes observed is a product of fracture-driven iceberg disintegration and dimensional reductions through melting. We suggest that changes in the characteristic size-frequency scaling of icebergs can be explained by the emergence of a dominant set of driving processes of iceberg degradation towards the open ocean. Consequently, the size-frequency distribution required to model iceberg distributions accurately must vary according to distance from the calving front

The initiator methionine tRNA drives secretion of type II collagen from stromal fibroblasts to promote tumor growth and angiogenesis

Summary: Expression of the initiator methionine tRNA (tRNAi Met) is deregulated in cancer. Despite this fact, it is not currently known how tRNAi Met expression levels influence tumor progression. We have found that tRNAi Met expression is increased in carcinoma-associated fibroblasts, implicating deregulated expression of tRNAi Met in the tumor stroma as a possible contributor to tumor progression. To investigate how elevated stromal tRNAi Met contributes to tumor progression, we generated a mouse expressing additional copies of the tRNAi Met gene (2+tRNAi Met mouse). Growth and vascularization of subcutaneous tumor allografts was enhanced in 2+tRNAi Met mice compared with wild-type littermate controls. Extracellular matrix (ECM) deposited by fibroblasts from 2+tRNAi Met mice supported enhanced endothelial cell and fibroblast migration. SILAC mass spectrometry indicated that elevated expression of tRNAi Met significantly increased synthesis and secretion of certain types of collagen, in particular type II collagen. Suppression of type II collagen opposed the ability of tRNAi Metoverexpressing fibroblasts to deposit pro-migratory ECM. We used the prolyl hydroxylase inhibitor ethyl- 3,4-dihydroxybenzoate (DHB) to determine whether collagen synthesis contributes to the tRNAi Met-driven pro-tumorigenic stroma in vivo. DHB had no effect on the growth of syngeneic allografts in wild-type mice but opposed the ability of 2+tRNAi Met mice to support increased angiogenesis and tumor growth. Finally, collagen II expression predicts poor prognosis in high-grade serous ovarian carcinoma. Taken together, these data indicate that increased tRNAi Met levels contribute to tumor progression by enhancing the ability of stromal fibroblasts to synthesize and secrete a type II collagen-rich ECM that supports endothelial cell migration and angiogenesis

A nucleosome turnover map reveals that the stability of histone H4 Lys20 methylation depends on histone recycling in transcribed chromatin

Nucleosome composition actively contributes to chromatin structure and accessibility. Cells have developed mechanisms to remove or recycle histones, generating a landscape of differentially aged nucleosomes. This study aimed to create a high-resolution, genome-wide map of nucleosome turnover in Schizosaccharomyces pombe. The recombination-induced tag exchange (RITE) method was used to study replication-independent nucleosome turnover through the appearance of new histone H3 and the disappearance or preservation of old histone H3. The genome-wide location of histones was determined by chromatin immunoprecipitation–exonuclease methodology (ChIP-exo). The findings were compared with diverse chromatin marks, including histone variant H2A.Z, post-translational histone modifications, and Pol II binding. Finally, genome-wide mapping of the methylation states of H4K20 was performed to determine the relationship between methylation (mono, di, and tri) of this residue and nucleosome turnover. Our analysis showed that histone recycling resulted in low nucleosome turnover in the coding regions of active genes, stably expressed at intermediate levels. High levels of transcription resulted in the incorporation of new histones primarily at the end of transcribed units. H4K20 was methylated in low-turnover nucleosomes in euchromatic regions, notably in the coding regions of long genes that were expressed at low levels. This transcription-dependent accumulation of histone methylation was dependent on the histone chaperone complex FACT. Our data showed that nucleosome turnover is highly dynamic in the genome and that several mechanisms are at play to either maintain or suppress stability. In particular, we found that FACT-associated transcription conserves histones by recycling them and is required for progressive H4K20 methylation

Barn-Raising on the Digital Frontier: The L.A.U.N.C.H. Collaborative

A meta-analysis of oncology papers from around the world revealed that cancer patients who lived more than 50 miles away from hospital centers routinely presented with more advanced stages of disease at diagnosis, exhibited lower adherence to prescribed treatments, presented with poorer diagnoses, and reported a lower quality of life than patients who lived nearer to care facilities. Connected health approaches—or the use of broadband and telecommunications technologies to evaluate, diagnose, and monitor patients beyond the clinic—are becoming an indispensable tool in medicine to overcome the obstacle of distance

Silencing RNAs expressed from W-linked PxyMasc “retrocopies” target that gene during female sex determination in Plutella xylostella

The Lepidoptera are an insect order of cultural, economic, and environmental importance, representing ∼10% of all described living species. Yet, for all but one of these species (silkmoth, Bombyx mori), the molecular genetics of how sexual fate is determined remains unknown. We investigated this in the diamondback moth (Plutella xylostella), a globally important, highly invasive, and economically damaging pest of cruciferous crops. Our previous work uncovered a regulator of male sex determination in P. xylostella—PxyMasc, a homolog of B. mori Masculinizer—which, although initially expressed in embryos of both sexes, is then reduced in female embryos, leading to female-specific splicing of doublesex. Here, through sequencing small RNA libraries generated from early embryos and sexed larval pools, we identified a variety of small silencing RNAs (predominantly Piwi-interacting RNAs [piRNAs]) complementary to PxyMasc, whose temporal expression correlated with the reduction in PxyMasc transcript observed previously in females. Analysis of these small RNAs showed that they are expressed from tandemly arranged, multicopy arrays found exclusively on the W (female-specific) chromosome, which we term “Pxyfem”. Analysis of the Pxyfem sequences showed that they are partial complementary DNAs (cDNAs) of PxyMasc messenger RNA (mRNA) transcripts, likely integrated into transposable element graveyards by the noncanonical action of retrotransposons (retrocopies), and that their apparent similarity to B. mori feminizer more probably represents convergent evolution. Our study helps elucidate the sex determination cascade in this globally important pest and highlights the “shortcuts” that retrotransposition events can facilitate in the evolution of complex molecular cascades, including sex determination

Mobile Air Quality Studies (MAQS) - an international project

Due to an increasing awareness of the potential hazardousness of air pollutants, new laws, rules and guidelines have recently been implemented globally. In this respect, numerous studies have addressed traffic-related exposure to particulate matter using stationary technology so far. By contrast, only few studies used the advanced technology of mobile exposure analysis. The Mobile Air Quality Study (MAQS) addresses the issue of air pollutant exposure by combining advanced high-granularity spatial-temporal analysis with vehicle-mounted, person-mounted and roadside sensors. The MAQS-platform will be used by international collaborators in order 1) to assess air pollutant exposure in relation to road structure, 2) to assess air pollutant exposure in relation to traffic density, 3) to assess air pollutant exposure in relation to weather conditions, 4) to compare exposure within vehicles between front and back seat (children) positions, and 5) to evaluate "traffic zone"- exposure in relation to non-"traffic zone"-exposure. Primarily, the MAQS-platform will focus on particulate matter. With the establishment of advanced mobile analysis tools, it is planed to extend the analysis to other pollutants including including NO2, SO2, nanoparticles, and ozone

Assessment of the quality and variability of health information on chronic pain websites using the DISCERN instrument

<p>Abstract</p> <p>Background</p> <p>The Internet is used increasingly by providers as a tool for disseminating pain-related health information and by patients as a resource about health conditions and treatment options. However, health information on the Internet remains unregulated and varies in quality, accuracy and readability. The objective of this study was to determine the quality of pain websites, and explain variability in quality and readability between pain websites.</p> <p>Methods</p> <p>Five key terms (pain, chronic pain, back pain, arthritis, and fibromyalgia) were entered into the Google, Yahoo and MSN search engines. Websites were assessed using the DISCERN instrument as a quality index. Grade level readability ratings were assessed using the Flesch-Kincaid Readability Algorithm. Univariate (using alpha = 0.20) and multivariable regression (using alpha = 0.05) analyses were used to explain the variability in DISCERN scores and grade level readability using potential for commercial gain, health related seals of approval, language(s) and multimedia features as independent variables.</p> <p>Results</p> <p>A total of 300 websites were assessed, 21 excluded in accordance with the exclusion criteria and 110 duplicate websites, leaving 161 unique sites. About 6.8% (11/161 websites) of the websites offered patients' commercial products for their pain condition, 36.0% (58/161 websites) had a health related seal of approval, 75.8% (122/161 websites) presented information in English only and 40.4% (65/161 websites) offered an interactive multimedia experience. In assessing the quality of the unique websites, of a maximum score of 80, the overall average DISCERN Score was 55.9 (13.6) and readability (grade level) of 10.9 (3.9). The multivariable regressions demonstrated that website seals of approval (<it>P </it>= 0.015) and potential for commercial gain (<it>P </it>= 0.189) were contributing factors to higher DISCERN scores, while seals of approval (<it>P </it>= 0.168) and interactive multimedia (<it>P </it>= 0.244) contributed to lower grade level readability, as indicated by estimates of the beta coefficients.</p> <p>Conclusion</p> <p>The overall quality of pain websites is moderate, with some shortcomings. Websites that scored high using the DISCERN questionnaire contained health related seals of approval and provided commercial solutions for pain related conditions while those with low readability levels offered interactive multimedia options and have been endorsed by health seals.</p

Study of Radiologic Technologists’ Perceptions of Picture Archiving and Communication System (PACS) Competence and Educational Issues in Western Australia

Although the implementation of picture archiving and communication system (PACS) could increase productivity of radiology departments, this depends on factors such as the PACS competence of radiologic technologists (RTs). The purpose of this study was to investigate the RTs’ perceptions of PACS competence and educational issues in Western Australia (WA). A hardcopy questionnaire was distributed to WA RTs for obtaining their perceptions of PACS competence and educational issues. Descriptive (percentage of frequency, mean and standard deviation) and inferential statistics (t test and analysis of variance) were used to analyze the responses of the multiple choice and five-point scale questions from the returned questionnaires. The questionnaire response rate was 57.7 % (173 out of 300). The mean values of all PACS competence questions except questions 2e–g are in the range of 3.9–4.9, i.e., around competent to very competent. Participants indicated they received adequate PACS training (mean 3.8). Statistically significant variables influencing RTs’ perceptions of their PACS competence and educational issues including the age (p < 0.01), gender (p < 0.05), years of practice (p < 0.005–0.05), primary duty (p < 0.05), medical imaging qualification (p < 0.001), general computer skills (p < 0.001), and type of PACS education received (p < 0.001–0.05). The WA RTs indicated that they were competent in using the modality workstation, PACS and radiology information system, and received adequate training. However, future PACS education programs should be tailored to different RTs’ groups. For example, multiple training modules might be necessary to support the PACS competence development of older RTs and those with lower general computer literacy

Data standards for transcatheter aortic valve implantation: the European Unified Registries for Heart Care Evaluation and Randomised Trials (EuroHeart)

Funding: European Society of Cardiology.publishersversionepub_ahead_of_prin