How enhancers regulate wavelike gene expression patterns

A key problem in development is to understand how genes turn on or off at the right place and right time during embryogenesis. Such decisions are made by non-coding sequences called ‘enhancers.’ Much of our models of how enhancers work rely on the assumption that genes are activated de novo as stable domains across embryonic tissues. Such a view has been strengthened by the intensive landmark studies of the early patterning of the anterior-posterior (AP) axis of the Drosophila embryo, where indeed gene expression domains seem to arise more or less stably. However, careful analysis of gene expression patterns in other model systems (including the AP patterning in vertebrates and short-germ insects like the beetle Tribolium castaneum) painted a different, very dynamic view of gene regulation, where genes are oftentimes expressed in a wavelike fashion. How such gene expression waves are mediated at the enhancer level is so far unclear. Here, we establish the AP patterning of the short-germ beetle Tribolium as a model system to study dynamic and temporal pattern formation at the enhancer level. To that end, we established an enhancer prediction system in Tribolium based on time- and tissue-specific ATAC-seq and an enhancer live reporter system based on MS2 tagging. Using this experimental framework, we discovered several Tribolium enhancers, and assessed the spatiotemporal activities of some of them in live embryos. We found our data consistent with a model in which the timing of gene expression during embryonic pattern formation is mediated by a balancing act between enhancers that induce rapid changes in gene expression patterns (that we call ‘dynamic enhancers’) and enhancers that stabilize gene expression patterns (that we call ‘static enhancers’). However, more data is needed for a strong support for this or any other alternative models

Sentinel-2 web platform for REDD+ monitoring. Online web platform for browsing and processing Sentinel-2 data for forest cover monitoring over the Tropics

The recent availability of time series of Sentinel-2 imagery represents a significant technological step in the use of Earth Observation (EO) data for forest cover monitoring. The 5 days revisiting time (S-2 A and S-2B satellites) and the 10m spatial resolution imply the need for much larger storage and processing resources than ever. To facilitate the use of Sentinel-2 imagery by national forestry services in the tropics (in particular in relation to REDD+ activities), the JRC has developed the Sentinel-2 web platform, an online Web system which is aimed at browsing, exploring and processing the full dataset of Sentinel-2 imagery available over theTropical belt.JRC.D.1-Bio-econom

Prions in Milk from Ewes Incubating Natural Scrapie

Since prion infectivity had never been reported in milk, dairy products originating from transmissible spongiform encephalopathy (TSE)-affected ruminant flocks currently enter unrestricted into the animal and human food chain. However, a recently published study brought the first evidence of the presence of prions in mammary secretions from scrapie-affected ewes. Here we report the detection of consistent levels of infectivity in colostrum and milk from sheep incubating natural scrapie, several months prior to clinical onset. Additionally, abnormal PrP was detected, by immunohistochemistry and PET blot, in lacteal ducts and mammary acini. This PrPSc accumulation was detected only in ewes harbouring mammary ectopic lymphoid follicles that developed consequent to Maedi lentivirus infection. However, bioassay revealed that prion infectivity was present in milk and colostrum, not only from ewes with such lympho-proliferative chronic mastitis, but also from those displaying lesion-free mammary glands. In milk and colostrum, infectivity could be recovered in the cellular, cream, and casein-whey fractions. In our samples, using a Tg 338 mouse model, the highest per ml infectious titre measured was found to be equivalent to that contained in 6 µg of a posterior brain stem from a terminally scrapie-affected ewe. These findings indicate that both colostrum and milk from small ruminants incubating TSE could contribute to the animal TSE transmission process, either directly or through the presence of milk-derived material in animal feedstuffs. It also raises some concern with regard to the risk to humans of TSE exposure associated with milk products from ovine and other TSE-susceptible dairy species

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

DSLM Principle

<p>DSLM Principle</p

Comparative embryonic morphogenesis of emerging insect model organisms

The fruit fly Drosophila melanogaster is one of the most important biological model organisms, but only the comparative approach with closely related species provides insights into the evolutionary diversification of insects. Of particular interest is the live imaging of fluorophores in developing embryos. It provides data for the analysis and comparison of the threedimensional morphogenesis as a function of time. However, for all species apart from Drosophila, for example the red flour beetle Tribolium castaneum, essentially no established standard operation procedures are available and the pool of data and resources is sparse. The goal of my PhD project was to address these limitations. I was able to accomplish the following milestones: - Development of the hemisphere and cobweb mounting methods for the non-invasive imaging of Tribolium embryos in light sheet-based fluorescence microscopes and characterization of most crucial embryogenetic events. - Comprehensive documentation of methods as protocols that describe (i) beetle rearing in the laboratory, (ii) preparation of embryos, (ii) calibration of light sheet-based fluorescence microscopes, (iv) recording over several days, (v) embryo retrieval as a quality control as well as (vi) data processing. - Adaption of the methods to record and analyze embryonic morphogenesis of the Mediterranean fruit fly Ceratitis capitata and the two-spotted cricket Gryllus bimaculatus as well as integration of the data into an evolutionary context. - Further development of the hemisphere method to allow the bead-based / landmark-based registration and fusion of three-dimensional images acquired along multiple directions to compensate the shadowing effect. - Development of the BugCube, a web-based computer program that allows to share image data, which was recorded by using light sheet-based fluorescence microscopy, with colleagues. - Invention and experimental proof-of-principle of the (i) AGameOfClones vector concept that creates homozygous transgenic insect lines systematically. Additionally, partial proof-of-principle of the (ii) AClashOfStrings vector concept that creates double homozygous transgenic insect lines systematically, as well as preliminary evaluation of the (iii) AStormOfRecords vector concept that creates triple homozygous transgenic insect lines systematically. - Creation and performance screening of more than fifty transgenic Tribolium lines for the long-term imaging of embryogenesis in fluorescence microscopes, including the first Lifeact and histone subunit-based lines. My primary results contribute significantly to the advanced fluorescence imaging approaches of insect species beyond Drosophila. The image data can be used to compare different strategies of embryonic morphogenesis and thus to interpret the respective phylogenetic context. My technological developments extend the methodological arsenal for insect model organisms considerably. Within my perspective, I emphasize the importance of non-invasive long-term fluorescence live imaging to establish speciesspecific morphogenetic standards, discuss the feasibly of a morphologic ontology on the cellular level, suggest the ‘nested linearly decreasing phylogenetic relationship’ approach for evolutionary developmental biology, propose the live imaging of species hybrids to investigate speciation and finally outline how light sheet-based fluorescence microscopy contributes to the transition from on-demand to systematic data acquisition in developmental biology. During my PhD project, I wrote a total of ten manuscripts, six of which were already published in peer-reviewed scientific journals. Additionally, I supervised four Master and two Bachelor projects whose scientific questions were inspired by the topic of my PhD work

Author correction: A deterministic genotyping workflow reduces waste of transgenic individuals by two-thirds

The original version of this Article contained errors where Table S5 and Table S6 were incorrectly cited. As the result, in the Methods section, under the subheading ‘Germline transformation, crossing setups and insertion junction sequencing’, “Progeny were scored for transformation marker presence during either the larval, pupal and adult stage by using a fluorescence stereo microscope (SteREO Discovery.V8, Zeiss) with appropriate filter sets (Table S4).” now reads: “Progeny were scored for transformation marker presence during either the larval, pupal and adult stage by using a fluorescence stereo microscope (SteREO Discovery.V8, Zeiss) with appropriate filter sets (Table S5).” And, under the subheading ‘Light sheet-based fluorescence microscopy’, “Metadata for the three datasets are provided in Table S5.” now reads: “Metadata for the three datasets are provided in Table S6.” In Data availability section, “Microscopy data can be accessed as described in Table S5.” now reads: “Microscopy data can be accessed as described in Table S6.” Additionally, in the Supplementary Information 8 file, the “Data Access” row was omitted in Table S6. The “Data Access” row now reads: Dataset (DS) DS0001 DS0002 DS0003 Dataset Access DOI: 10.5281/zenodo.4892363 DOI: 10.5281/zenodo.4892373 DOI: 10.5281/zenodo.4892381 The original Supplementary Information 8 file is provided below. Finally, the Supplementary Information 1 and 5 files published with this Article contained tracked changes, these have now been removed. The original Article and accompanying Supplementary Information files have been corrected

A deterministic genotyping workflow reduces waste of transgenic individuals by two-thirds

We present a deterministic workflow for genotyping single and double transgenic individuals directly upon nascence that prevents overproduction and reduces wasted animals by two-thirds. In our vector concepts, transgenes are accompanied by two of four clearly distinguishable transformation markers that are embedded in interweaved, but incompatible Lox site pairs. Following Cre-mediated recombination, the genotypes of single and double transgenic individuals were successfully identified by specific marker combinations in 461 scorings

In toto light sheet fluorescence microscopy live imaging datasets of Ceratitis capitata embryonic development

The Mediterranean fruit fly (medfly), Ceratitis capitata, is an important model organism in biology and agricultural research with high economic relevance. However, information about its embryonic development is still sparse. We share nine long-term live imaging datasets acquired with light sheet fluorescence microscopy (484.5 h total recording time, 373 995 images, 256 Gb) with the scientific community. Six datasets show the embryonic development in toto for about 60 hours at 30 minutes intervals along four directions in three spatial dimensions, covering approximately 97% of the entire embryonic development period. Three datasets focus on germ cell formation and head involution. All imaged embryos hatched morphologically intact. Based on these data, we suggest a two-level staging system that functions as a morphogenetic framework for upcoming studies on medfly. Our data supports research on wild-type or aberrant morphogenesis, quantitative analyses, comparative approaches to insect development as well as studies related to pest control. Further, they can be used to test advanced image processing approaches or to train machine learning algorithms and/or neuronal networks