The Different Function of Single Phosphorylation Sites of Drosophila melanogaster Lamin Dm and Lamin C

Lamins' functions are regulated by phosphorylation at specific sites but our understanding of the role of such modifications is practically limited to the function of cdc 2 (cdk1) kinase sites in depolymerization of the nuclear lamina during mitosis. In our study we used Drosophila lamin Dm (B-type) to examine the function of particular phosphorylation sites using pseudophosphorylated mutants mimicking single phosphorylation at experimentally confirmed in vivo phosphosites (S25E, S45E, T435E, S595E). We also analyzed lamin C (A-type) and its mutant S37E representing the N-terminal cdc2 (mitotic) site as well as lamin Dm R64H mutant as a control, non-polymerizing lamin. In the polymerization assay we could observe different effects of N-terminal cdc2 site pseudophosphorylation on A- and B-type lamins: lamin Dm S45E mutant was insoluble, in contrast to lamin C S37E. Lamin Dm T435E (C-terminal cdc2 site) and R64H were soluble in vitro. We also confirmed that none of the single phosphorylation site modifications affected the chromatin binding of lamin Dm, in contrast to the lamin C N-terminal cdc2 site. In vivo, all lamin Dm mutants were incorporated efficiently into the nuclear lamina in transfected Drosophila S2 and HeLa cells, although significant amounts of S45E and T435E were also located in cytoplasm. When farnesylation incompetent mutants were expressed in HeLa cells, lamin Dm T435E was cytoplasmic and showed higher mobility in FRAP assay

Embryonic and adult isoforms of XLAP2 form microdomains associated with chromatin and the nuclear envelope

Laminin-associated polypeptide 2 (LAP2) proteins are alternatively spliced products of a single gene; they belong to the LEM domain family and, in mammals, locate to the nuclear envelope (NE) and nuclear lamina. Isoforms lacking the transmembrane domain also locate to the nucleoplasm. We used new specific antibodies against the N-terminal domain of Xenopus LAP2 to perform immunoprecipitation, identification and localization studies during Xenopus development. By immunoprecipitation and mass spectrometry (LC/MS/MS), we identified the embryonic isoform XLAP2γ, which was downregulated during development similarly to XLAP2ω. Embryonic isoforms XLAP2ω and XLAP2γ were located in close association with chromatin up to the blastula stage. Later in development, both embryonic isoforms and the adult isoform XLAP2β were localized in a similar way at the NE. All isoforms colocalized with lamin B2/B3 during development, whereas XLAP2β was colocalized with lamin B2 and apparently with the F/G repeat nucleoporins throughout the cell cycle in adult tissues and culture cells. XLAP2β was localized in clusters on chromatin, both at the NE and inside the nucleus. Embryonic isoforms were also localized in clusters at the NE of oocytes. Our results suggest that XLAP2 isoforms participate in the maintenance and anchoring of chromatin domains to the NE and in the formation of lamin B microdomains

Effects of zebra mussels on cladoceran communities under eutrophic conditions

The purpose of this study was to determine how zebra mussels affected cladoceran community structure under eutrophic conditions. We conducted a mesocosm study where we manipulated the presence of zebra mussels and the presence of large-bodied Daphnia (Daphnia magna and Daphnia pulicaria). We also conducted a complimentary life-table experiment to determine how water from the zebra mussel treatment affected the life history characteristics of the cladoceran species. We anticipated that small- and large-bodied cladoceran species would respond differently to changes in algal quality and quantity under the effects of zebra mussels. Large-bodied Daphnia successfully established in the zebra mussel treatment but failed to grow in the control. We did not observe positive relationships between food concentrations and cladoceran abundances. However, the phosphorus content in the seston indicated that food quality was below the threshold level for large-bodied cladocerans at the beginning of the experiment. We believe that zebra mussels quickly enhanced the phosphorus content in the seston due to the excretion of inorganic phosphorus, thus facilitating the development of large-bodied Daphnia. In conclusion, our results suggest that zebra mussels can alter the phosphorus content of seston in lakes and this can affect the dynamics of crustacean zooplankton

Understanding Marine Mussel Adhesion

In addition to identifying the proteins that have a role in underwater adhesion by marine mussels, research efforts have focused on identifying the genes responsible for the adhesive proteins, environmental factors that may influence protein production, and strategies for producing natural adhesives similar to the native mussel adhesive proteins. The production-scale availability of recombinant mussel adhesive proteins will enable researchers to formulate adhesives that are water-impervious and ecologically safe and can bind materials ranging from glass, plastics, metals, and wood to materials, such as bone or teeth, biological organisms, and other chemicals or molecules. Unfortunately, as of yet scientists have been unable to duplicate the processes that marine mussels use to create adhesive structures. This study provides a background on adhesive proteins identified in the blue mussel, Mytilus edulis, and introduces our research interests and discusses the future for continued research related to mussel adhesion

Recent approaches in designing bioadhesive materials inspired by mussel adhesive protein

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface drying properties, control of the oxidation state of catechol, among other features. We also summarized recent developments in designing advanced biomimetic materials including coacervate-forming adhesives, mechanically improved nano- and micro-composite adhesive hydrogels, as well as smart and self-healing materials. Finally, we review the applications of catechol-functionalized materials for the use as biomedical adhesives, therapeutic applications, and antifouling coatings

Regional Patterns of Late Medieval and Early Modern European Building Activity Revealed by Felling Dates

Although variations in building activity are a useful indicator of societal well-being and demographic development, historical datasets for larger regions and longer periods are still rare. Here, we present 54,045 annually precise dendrochronological felling dates from historical construction timber from across most of Europe between 1250 and 1699 CE to infer variations in building activity. We use geostatistical techniques to compare spatiotemporal dynamics in past European building activity against independent demographic, economic, social and climatic data. We show that the felling dates capture major geographical patterns of demographic trends, especially in regions with dense data coverage. A particularly strong negative association is found between grain prices and the number of felling dates. In addition, a significant positive association is found between the number of felling dates and mining activity. These strong associations, with well-known macro-economic indicators from pre-industrial Europe, corroborate the use of felling dates as an independent source for exploring large-scale fluctuations of societal well-being and demographic development. Three prominent examples are the building boom in the Hanseatic League region of northeastern Germany during the 13th century, the onset of the Late Medieval Crisis in much of Europec. 1300, and the cessation of building activity in large parts of central Europe during armed conflicts such as the Thirty Years’ War (1618–1648 CE). Despite new insights gained from our European-wide felling date inventory, further studies are needed to investigate changes in construction activity of high versus low status buildings, and of urban versus rural buildings, and to compare those results with a variety of historical documentary sources and natural proxy archives.</jats:p

3D visualization for the MARS14 Code

A new three-dimensional visualization engine has been developed for the MARS14 code system. It is based on the OPENINVENTOR graphics library and integrated with the MARS built-in two-dimensional Graphical-User Interface, MARS-GUI-SLICE. The integrated package allows thorough checking of complex geometry systems and their fragments, materials, magnetic fields, particle tracks along with a visualization of calculated 2-D histograms. The algorithms and their optimization are described for two geometry classes along with examples in accelerator and detector applications

3D visualization for the MARS14 Code

A new three-dimensional visualization engine has been developed for the MARS14 code system. It is based on the OPENINVENTOR graphics library and integrated with the MARS built-in two-dimensional Graphical-User Interface, MARS-GUI-SLICE. The integrated package allows thorough checking of complex geometry systems and their fragments, materials, magnetic fields, particle tracks along with a visualization of calculated 2-D histograms. The algorithms and their optimization are described for two geometry classes along with examples in accelerator and detector applications