DNA methylation and methyl-CpG binding proteins: developmental requirements and function

DNA methylation is a major epigenetic modification in the genomes of higher eukaryotes. In vertebrates, DNA methylation occurs predominantly on the CpG dinucleotide, and approximately 60% to 90% of these dinucleotides are modified. Distinct DNA methylation patterns, which can vary between different tissues and developmental stages, exist on specific loci. Sites of DNA methylation are occupied by various proteins, including methyl-CpG binding domain (MBD) proteins which recruit the enzymatic machinery to establish silent chromatin. Mutations in the MBD family member MeCP2 are the cause of Rett syndrome, a severe neurodevelopmental disorder, whereas other MBDs are known to bind sites of hypermethylation in human cancer cell lines. Here, we review the advances in our understanding of the function of DNA methylation, DNA methyltransferases, and methyl-CpG binding proteins in vertebrate embryonic development. MBDs function in transcriptional repression and long-range interactions in chromatin and also appear to play a role in genomic stability, neural signaling, and transcriptional activation. DNA methylation makes an essential and versatile epigenetic contribution to genome integrity and function

SETDB1 Is Involved in Postembryonic DNA Methylation and Gene Silencing in Drosophila

DNA methylation is fundamental for the stability and activity of genomes. Drosophila melanogaster and vertebrates establish a global DNA methylation pattern of their genome during early embryogenesis. Large-scale analyses of DNA methylation patterns have uncovered revealed that DNA methylation patterns are dynamic rather than static and change in a gene-specific fashion during development and in diseased cells. However, the factors and mechanisms involved in dynamic, postembryonic DNA methylation remain unclear. Methylation of lysine 9 in histone H3 (H3-K9) by members of the Su(var)3–9 family of histone methyltransferases (HMTs) triggers embryonic DNA methylation in Arthropods and Chordates. Here, we demonstrate that Drosophila SETDB1 (dSETDB1) can mediate DNA methylation and silencing of genes and retrotransposons. We found that dSETDB1 tri-methylates H3-K9 and binds methylated CpA motifs. Tri-methylation of H3-K9 by dSETDB1 mediates recruitment of DNA methyltransferase 2 (Dnmt2) and Su(var)205, the Drosophila ortholog of mammalian “Heterochromatin Protein 1”, to target genes for dSETDB1. By enlisting Dnmt2 and Su(var)205, dSETDB1 triggers DNA methylation and silencing of genes and retrotransposons in Drosophila cells. DSETDB1 is involved in postembryonic DNA methylation and silencing of Rt1b{} retrotransposons and the tumor suppressor gene retinoblastoma family protein 1 (Rb) in imaginal discs. Collectively, our findings implicate dSETDB1 in postembryonic DNA methylation, provide a model for silencing of the tumor suppressor Rb, and uncover a role for cell type-specific DNA methylation in Drosophila development

The Application of DNA Barcodes for the Identification of Marine Crustaceans from the North Sea and Adjacent Regions

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequence

The functions of the teacher in the position of the school prevention worker

The diploma thesis deals with the topic of risk behavior prevention on the elementary schools. It focuses especially on the teachers who are in the position of the school prevention workers and their perceived level of preparedness with regard to their duties specified in reguletion. The aim of this thesis is aslo to identify the possibillities for improvement of their work on the field of school-based prevention

Die Abenteuer des Pumpot / Gerat Hendrich. Ill. von Jan Hempel

DIE ABENTEUER DES PUMPOT / GERAT HENDRICH. ILL. VON JAN HEMPEL Die Abenteuer des Pumpot / Gerat Hendrich. Ill. von Jan Hempel (1) Einband (1) Kapitel (10) Titelseite (12) Text (13) Impressum (65

Tepuidessus Spangler 1981

<i>Tepuidessus</i> Spangler, 1981 <p> <b>Type species.</b> <i>Tepuidessus breweri</i> Spangler, 1981, by original designation.</p> <p> <b> Revised diagnosis for <i>Tepuidessus</i></b> . Black Bidessini with dorsal surface densely setose; clypeus not modified; occipital line absent; basal striae on pronotum and elytra absent or present; sutural line on elytron absent; longitudinal elytral carina on disc absent; basal epipleural transverse carina absent; metathoracic wings reduced to short membranous vestiges without any sign of venation (Fig. 6); median lobe simple, with narrowed apical part in ventral view; parameres two-segmented. Species inhabiting tepui plateaus in Venezuela.</p> <p> Note that the presence/absence of pronotal and/or elytral striae has also been shown to possibly vary even within closely related species of other genera, e.g. <i>Limbodessus</i> Guignot, 1939 (see Balke <i>et al</i>. 2015).</p>Published as part of <i>Kodada, Jan, Hendrich, Lars & Balke, Michael, 2018, Tepuidessus grulai sp. nov. from Acopán Tepui in Venezuela (Coleoptera: Dytiscidae: Hydroporinae: Bidessini), pp. 561-572 in Zootaxa 4434 (3)</i> on page 562, DOI: 10.11646/zootaxa.4434.3.10, <a href="http://zenodo.org/record/1292243">http://zenodo.org/record/1292243</a&gt

Tepuidessus grulai sp. nov. from Acopán Tepui in Venezuela (Coleoptera: Dytiscidae: Hydroporinae: Bidessini)

Kodada, Jan, Hendrich, Lars, Balke, Michael (2018): Tepuidessus grulai sp. nov. from Acopán Tepui in Venezuela (Coleoptera: Dytiscidae: Hydroporinae: Bidessini). Zootaxa 4434 (3): 561-572, DOI: 10.11646/zootaxa.4434.3.1

Tepuidessus breweri Spangler 1981

<i>Tepuidessus breweri</i> Spangler, 1981 <p> <b>Type locality</b>. Roraima Tepui, 2,800 m, around 5.162N 60.764W, Venezuela. Remarks: The altitude of the plateau is only around 2,300 m according to GoogleEarth.</p> <p> <b>Material studied</b>. 3 exs, "Venezuela - Guyana Mt. Roraima rainwater pools on Tepui summit Dec. 1998 D.</p> <p>Bilton leg." (CLH, ZSM); 10 exs, " Venezuela (Bolivar) Gran Sabana, Mt. Roraima, 2500 m, 11.8.2001, Gottwald leg./Coll. Hendrich" (CLH, ZSM).</p> <p> <b>Diagnosis</b>. Length of beetle 1.6–1.8 mm, width 0.7 mm (2 mm / 0.84 mm according to the original description, which might be incorrect; we used a calibrated ocular micrometre for our measurement). Habitus appearing long oval (Figs 1, 2), with only slight discontinuity between pronotum and elytra. Pronotum broadest near posterior angles; basal pronotal striae absent (at most with shallow depressions instead; see Spangler 1981, Biström 1988 and Miller & Bergsten 2016). Elytra broadest in anterior third; basal elytral striae absent. Apical abdominal ventrite strongly bordered.</p> <p> <b>Habitat</b>. The species was suggested to be hygropetric, with specimens collected from underneath of mats of wet moss (Spangler 1981; Miller & Bergsten 2016), however, they were later also observed in rainwater puddles (D.T. Bilton pers. communication, S. Gottwald pers. communication) (Fig. 9).</p>Published as part of <i>Kodada, Jan, Hendrich, Lars & Balke, Michael, 2018, Tepuidessus grulai sp. nov. from Acopán Tepui in Venezuela (Coleoptera: Dytiscidae: Hydroporinae: Bidessini), pp. 561-572 in Zootaxa 4434 (3)</i> on pages 562-563, DOI: 10.11646/zootaxa.4434.3.10, <a href="http://zenodo.org/record/1292243">http://zenodo.org/record/1292243</a&gt

Tepuidessus grulai Kodada & Hendrich & Balke 2018, sp. nov.

<i>Tepuidessus grulai</i> sp. nov. <p> <b>Type locality</b>. Acopán Tepui, ca. 2,000 m, 5.194N 62.045W, Venezuela.</p> <p> <b>Holotype, male (ZSM): " Venezuela</b>: Estado Boliver, puddles on rocks in Acopantepui base camp" / " 2022m, 14.xi.2015, 5.19413°[N] -62.04478°[W], (VEN 6 /Nov2015)" / " Holotype <i>Tepuidessus grulai</i> sp. nov., Kodada, Hendrich & Balke des. 2018" [red printed label]. <b>Paratypes:</b> 43 exs with the same label data as holotype (CHF, CKB, MIZA, NMPC, ZSM). Each paratype is provided with a red printed paratype label.</p> <p> <b>Description of holotype</b>. Habitus slightly broad oval, outline with particularly distinct discontinuity between pronotum and elytra (Figs 3–4). Pronotum broadest before its midlength. Elytra widest at about midlength. Total length: 1.8 mm; maximum width: 0.9 mm.</p> <p> <b>Colouration</b>. Black dorsally, dark brown to black ventrally (Figs 3, 4, 5).</p> <p> <b>Surface sculpture</b>. Head with distinct microreticulation and few setiferous punctures (Fig. 4A). Pronotum and elytron shiny (Fig. 3A), mostly polished and distinct microreticulation only visible along pronotal margins; whole surface with dense and coarse setiferous punctation, exceptionally coarse and deep on disc (Fig. 6C). Ventral surface microreticulate, abdominal ventrites 3–6 shinier; venter with distinct setiferous punctation; posterior margins of ventrites 3–5 without denticles (present in Neotropical genus <i>Bidessodes</i> Régimbart, 1895; see Miller & Bergsten 2016).</p> <p> <b>Structures</b>. Antenna stout, moniliform. Head without occipital line and with rounded clypeus (as in Fig. 4). Pronotum without lateral bead; with distinct and very deep basal striae (as in Figs 6A, C). Elytron with short and deep basal striae, but without sutural line, with distinct longitudinal depression on elytral disc roughly in middle of each elytron (as in Fig. 3B, arrow). Basal epipleural transverse carina absent. Metathoracic wings vestigial, reduced to short membranous vestiges without any sign of venation (Fig. 6). Pro- and mesotarsi appearing stout because tarsomeres 1–3 distinctly dilated laterally; metatrochanter moderately offset.</p> <p> <b>Male genitalia</b>. Median lobe of aedeagus simply curved, long in lateral view; in ventral view, slender and gently narrowed towards tip (Figs 7A, B); lateral lobes (parameres) bisegmented and of a general Bidessini type (see Biström 1988), tip of distal joint rounded (Fig. 7A) and with no obvious "nose" or hook (as in e.g. Balke <i>et al</i>. 2015: fig. 31; Biström 1988: fig. 15).</p> <p> <b>Female</b>. Dorsal and ventral surface dull due to well impressed microreticulation between surface punctation (Figs 3B, 4B, 5). Apical ventrite flattened before posterior margin, tip in lateral view beak-shaped (Fig. 6B).</p> <p> <b>Size variation</b>. Total length: 1.7–1.8 mm; maximum width: 0.7–0.9 mm.</p> <p> <b>Differential diagnosis</b>. Using the key of Miller & Bergsten (2016: 220), the new species from Acopán Tepui does not key out with <i>Tepuidessus</i>, but with <i>Papuadessus</i> Balke, 2001, a genus endemic to the Papuan region. The two <i>Papuadessus</i> species are morphologically rather divergent and considered members of one lineage only based on DNA sequence data (Balke 2001; Balke <i>et al</i>. 2013; Miller & Bergsten 2016). In the absence of any obvious morphological apomorphy that would group the species treated here with <i>Papuadessus</i>, or indeed any other genus, we opt for the pragmatic approach to assign it to <i>Tepuidessus</i>.</p> <p> <i>Tepuidessus grulai</i> <b>sp. nov.</b> differs from <i>T. breweri</i> by (1) much broader habitus with distinct outline discontinuity between pronotum and elytra, (2) well developed, long and deep basal striae on pronotum and elytra and (3) by unbordered apical abdominal ventrite. The median lobe of aedeagus is more narrowed than in <i>T. breweri</i> in lateral view.</p> <p> <b>Etymology</b>. Named after Daniel Gruľa, one of the collectors of the new species. It is a noun in the genitive singular.</p> <p> <b>Distribution</b>. Only known from the type locality (Fig. 8). This locality is situated around 140 km west of Mount Roraima, the locality of the other Bidessini species described from the plateau of a tepui.</p> <p> <b>Habitat</b>. Puddles on rocks of summit plateau of Acopán Tepui (Fig. 10).</p>Published as part of <i>Kodada, Jan, Hendrich, Lars & Balke, Michael, 2018, Tepuidessus grulai sp. nov. from Acopán Tepui in Venezuela (Coleoptera: Dytiscidae: Hydroporinae: Bidessini), pp. 561-572 in Zootaxa 4434 (3)</i> on pages 563-566, DOI: 10.11646/zootaxa.4434.3.10, <a href="http://zenodo.org/record/1292243">http://zenodo.org/record/1292243</a&gt