A novel wound-inducible extensin gene is expressed early in newly isolated protoplasts of Nicotiana sylvestris

A cDNA clone (6PExt 1.2) encoding a novel extensin was isolated from a cDNA library made from 6 h old mesophyll protoplasts of Nicotiana sylvestris. The screening was performed with a heterologous probe from carrot. The encoded polypeptide showed features characteristic of hydroxyproline-rich glycoproteins such as Ser-(Pro)₄ repeats and a high content in Tyr and Lys residues. The presence of four Tyr-X-Tyr-Lys motifs suggests the possibility for intramolecular isodityrosine cross-links whereas three Val-Tyr-Lys motifs may participate in intermolecular cross-links. The analysis of genomic DNA gel blots using both the N. sylvestris and the carrot clones as probes showed that the 6PExt 1.2 gene belongs to a complex multigene family encoding extensin and extensin-related polypeptides in N. sylvestris as well as in related Nicotianeae including a laboratory hybrid. This was confirmed by the analysis of RNA gel blots: a set of mRNAs ranging in size from 0.3 kb to 3.5 kb was found by the carrot extensin probe. The 6PExt 1.2 probe found a 1.2 kb mRNA in protoplasts and in wounded tissues as well as a 0.9 kb mRNA which seemed to be stem-specific. The gene encoding 6PExt 1.2 was induced by wounding in protoplasts, in leaf strips and after Agrobacterium tumefaciens infection of stems.     

The fate of intraperitoneally injected carbon particles in cyprinid fish

Summary The lymphoid organs of rosy barb (Barbus conchonius) and carp (Cyprinus carpio) were investigated for their phagocytic uptake of carbon, after its intraperitoneal injection. Carbon handling was similar in both species. It was first detected in the lymphoid organs at 30 min after injection. During the first day, carbon was phagocytized by macrophages situated in the spleen within the ellipsoids and in the red pulp. In head and trunk kidney, carbon was found in macrophages scattered throughout the haemopoietic parenchyma, and in cells lining the blood sinuses. In the spleen, macrophages replete with carbon left the ellipsoidal structures and formed aggregates with pigment-containing macrophages from day 6 onwards. In all lymphoid organs, almost all carbon was ultimately concentrated in the melano-macrophage centres.     

Synthesis and CHK1 inhibitory potency of Hymenialdisine analogues

A series of thieno[3,2-b]pyrroloazepinones derivatives related to Hymenialdisine were prepared and tested for CHK1 inhibitory activity. Nanomolar inhibitions were achieved when electron-withdrawing substituents were introduced at position 3 of the thiophene ring.     

Postnatal neural precursor cell regions in the rostral subventricular zone, hippocampal subgranular zone and cerebellum of the dog (Canis lupus familiaris)

Identification of neural stem and progenitor cells (NPCs) in vitro and in vivo is essential to the use of developmental and disease models of neurogenesis. The dog is a valuable large animal model for multiple neurodegenerative diseases and is more closely matched to humans than rodents with respect to brain organization and complexity. It is therefore important to determine whether immunohistochemical markers associated with NPCs in humans and rodents are also appropriate for the dog. The NPC markers CD15, CD133, nestin, GFAP and phosphacan (DSD-1) were evaluated in situ in the canine rostral telencephalon, hippocampal dentate gyrus, and cerebellum at different postnatal time-points. Positive staining results were interpreted in the context of region and cellular morphology. Our results showed that neurospheres and cells within the rostral subventricular zone (SVZ), dentate gyrus subgranular zone (SGZ), and white matter tracts of the cerebellum were immunopositive for CD15, nestin and GFAP. Neurospheres and the cerebellum were immunonegative for CD133, whereas CD133 staining was present in the postnatal rostral SVZ. Anti-phosphacan antibody staining delineated the neurogenic niches of the rostral lateral ventricle SVZ and the hippocampal SGZ. Positive staining for phosphacan was also noted in white matter tracts of the cerebellum and within the Purkinje layer. Our results showed that in the dog these markers were associated with regions shown to be neurogenic in rodents and primates.     

<Emphasis Type="Italic">Gluconobacter oxydans</Emphasis> NAD-dependent, <Emphasis Type="SmallCaps">D</Emphasis>-fructose reducing,polyol dehydrogenases activity: screening,medium optimisation and application for enzymatic polyol production

Gluconobacter oxydans LMG 1489 was selected as the best strain for NAD(P)-dependent polyol dehydrogenase production. The highest enzyme activities were obtained when this strain was cultivated on a medium consisting of 30 g glycerol l^–1, 7.2 g peptone l–1 and 1.8 g yeast extract l^–1. Two D-fructose reducing, NAD-dependent intracellular enzymes were present in the G. oxydans cell-free extract: sorbitol dehydrogenase, and mannitol dehydrogenase. Substrate reduction occurred optimally at a low pH (pH 6), while the optimum for substrate oxidation was situated at alkaline pHs (pH 9.5–10.5). The mannitol dehydrogenase was more thermostable than the sorbitol dehydrogenase. The cell-free extract could be used to produce D-mannitol and D-sorbitol enzymatically from D-fructose. Efficient coenzyme regeneration was accomplished by formate dehydrogenase-mediated oxidation of formate into CO₂.     

Climate–ecosystem modelling made easy: The Land Sites Platform

Dynamic Global Vegetation Models (DGVMs) provide a state-of-the-art process-based approach to study the complex interplay between vegetation and its physical environment. For example, they help to predict how terrestrial plants interact with climate, soils, disturbance and competition for resources. We argue that there is untapped potential for the use of DGVMs in ecological and ecophysiological research. One fundamental barrier to realize this potential is that many researchers with relevant expertize (ecology, plant physiology, soil science, etc.) lack access to the technical resources or awareness of the research potential of DGVMs. Here we present the Land Sites Platform (LSP): new software that facilitates single-site simulations with the Functionally Assembled Terrestrial Ecosystem Simulator, an advanced DGVM coupled with the Community Land Model. The LSP includes a Graphical User Interface and an Application Programming Interface, which improve the user experience and lower the technical thresholds for installing these model architectures and setting up model experiments. The software is distributed via version-controlled containers; researchers and students can run simulations directly on their personal computers or servers, with relatively low hardware requirements, and on different operating systems. Version 1.0 of the LSP supports site-level simulations. We provide input data for 20 established geo-ecological observation sites in Norway and workflows to add generic sites from public global datasets. The LSP makes standard model experiments with default data easily achievable (e.g., for educational or introductory purposes) while retaining flexibility for more advanced scientific uses. We further provide tools to visualize the model input and output, including simple examples to relate predictions to local observations. The LSP improves access to land surface and DGVM modelling as a building block of community cyberinfrastructure that may inspire new avenues for mechanistic ecosystem research across disciplines.     

Tubulin assembly, taxoid site binding, and cellular effects of the microtubule-stabilizing agent dictyostatin

(-)-Dictyostatin is a sponge-derived, 22-member macrolactone natural product shown to cause cells to accumulate in the G2/M phase of the cell cycle, with changes in intracellular microtubules analogous to those observed with paclitaxel treatment. Dictyostatin also induces assembly of purified tubulin more rapidly than does paclitaxel, and nearly as vigorously as does dictyostatin's close structural congener, (+)-discodermolide (Isbrucker et al. (2003), Biochem. Pharmacol. 65, 75-82). We used synthetic (-)-dictyostatin to study its biochemical and cytological activities in greater detail. The antiproliferative activity of dictyostatin did not differ greatly from that of paclitaxel or discodermolide. Like discodermolide, dictyostatin retained antiproliferative activity against human ovarian carcinoma cells resistant to paclitaxel due to beta-tubulin mutations and caused conversion of cellular soluble tubulin pools to microtubules. Detailed comparison of the abilities of dictyostatin and discodermolide to induce tubulin assembly demonstrated that the compounds had similar potencies. Dictyostatin inhibited the binding of radiolabeled discodermolide to microtubules more potently than any other compound examined, and dictyostatin and discodermolide had equivalent activity as inhibitors of the binding of both radiolabeled epothilone B and paclitaxel to microtubules. These results are consistent with the idea that the macrocyclic structure of dictyostatin represents the template for the bioactive conformation of discodermolide.