UDP-N-acetylglucosamine 1-carboxyvinyl-transferase from Acinetobacter calcoaceticus

Abstract We have analyzed the sequence downstream of rpoN from Zcinetobacter calcoaceticus and identified an open reading frame encoding a protein with high similarity to UDP- N -acetylgucosamine 1-carboxyvinyl-transferase (MurZ). Multicopy plasmids encoding this enzyme conferred phosphomycin resistance to A. calcoaceticus . The polar effect of a rpoN mutation on the phosphomycin resistance level suggests that murZ is, in part, cotranscribed with rpoN . These observations confirm that A. calcoaceticus represents the first exceptin from a conserved genetic context of rpoN observed in several other Gram-negative bacteria.     

Entomofauna resource distribution associated with pig cadavers in Bogotá DC

A cadaver represents a temporal energy‐loaded resource, which provides arthropods with food, protection and a place in which to find a mate. Insects are usually the first organisms to discover and colonize a cadaver; as decomposition progresses, insects colonize cadavers in a predictable sequence. This work aimed to establish cadaverous entomofauna relationships with regard to stages of decomposition and environmental conditions using multiple correspondence analysis and thereby to identify the way in which insects distribute a perishable and changing resource. Entomofauna were thus collected in a semi‐rural area near Bogotá from the cadavers of three pigs (Sus scrofa L.) which had been shot. Environmental variables were recorded for each sampling. Multiple correspondence analyses were carried out for adult forms belonging to Diptera and Coleoptera families and stages of decomposition, and for Diptera and Coleoptera adult forms and environmental conditions. Stages of decomposition were a primary determining factor for structuring four guilds of entomofauna. However, environmental conditions influenced insect activity and were therefore a relevant factor in the structure of the entomofauna community. The results showed that the insects' distribution of available resources was related to changes in the stage of decomposition.     

Dispersal vs. vicariance in the Mediterranean: historical biogeography of the Palearctic Pachydeminae (Coleoptera, Scarabaeoidea)

Aim The geological evolution of the Mediterranean region is largely the result of the Tertiary collision of the African and Eurasian Plates, but also a mosaic of migrating island arcs, fragmenting tectonic belts, and extending back‐arc basins. Such complex paleogeography has resulted in a ‘reticulate’ biogeographical history, in which Mediterranean biotas repeatedly fragmented and merged as dispersal barriers appeared and disappeared through time. In this study, dispersal‐vicariance analysis (DIVA) is used to assess the relative role played by dispersal and vicariance in shaping distribution patterns in the beetle subfamily Pachydeminae Reitter, 1902 (Scarabaeoidea), an example of east–west Mediterranean disjunction. Location The Mediterranean region, including North Africa, the western Mediterranean, Balkans–Anatolia, Middle East, Caucasus, the Iranian Plateau, and Central Asia. Methods A phylogenetic hypothesis of the Palearctic genera of Pachydeminae in conjunction with distributional data was analysed using DIVA. This method reconstructs the ancestral distribution in a given phylogeny based on the vicariance model, while allowing dispersal and extinction to occur. Unlike other methods, DIVA does not enforce area relationships to conform to a hierarchical ‘area cladogram’, so it can be used to reconstruct ‘reticulate’ biogeographical scenarios. Results Optimal reconstructions, requiring 23 dispersal events, suggest that the ancestor of Pachydeminae was originally present in the south‐east Mediterranean region. Basal splitting within the subfamily was caused by vicariance events related to the late Tertiary collision of the African microplates Apulia and Arabia with Eurasia, and the resultant arise of successive dispersal barriers (e.g. the Red Sea, the Zagros Mountains). Subsequent diversification in Pachydeminae involved multiple speciation events within the Middle East and Iran–Afghanistan regions, which gave rise to the least speciose genera of Pachydeminae (e.g. Otoclinius Brenske, 1896). Finally, the presence of Pachydeminae in the western Mediterranean region seems to be the result of a recent dispersal event. The ancestor of the Iberian genera Ceramida Baraud, 1987 and Elaphocera Gené, 1836 probably dispersed from the Middle East to the Iberian Peninsula across North Africa and the Gibraltar Strait during the ‘Messinian salinity crisis’ at the end of the Miocene. Main conclusions Although the basal diversification of Pachydeminae around the Mediterranean appears to be related to vicariance events linked to the geological formation of the Mediterranean Basin, dispersal has also played a very important role. Nearly 38% of the speciation events in the phylogeny resulted from dispersal to a new area followed by allopatric speciation between lineages. Relationships between western and eastern Mediterranean disjuncts are usually explained by dispersal through Central Europe. The biogeographical history of the Pachydeminae corroborates other biogeographical studies that consider North Africa to be an alternative dispersal route by which Mediterranean taxa could have achieved circum‐Mediterranean distributions.     

Assessment and comparison of neural morphology through metrical feature extraction and analysis in neuron and neuron–glia cultures

The morphology of dissociated single cerebellar Purkinje cells obtained from wild-type P1 CD1 mice was assessed in the absence and in the presence of glia. A dedicated noninvasive technique based on optical microscopy was developed. Image processing algorithms were implemented to extract metrical features characterizing cell structure and dendritic arborization. The morphological features were analyzed in order to identify quantitative differences in Purkinje cell morphology due to interactions with astrocytes.     

Historical and recent evidence for close relationships among Rickettsia parkeri,R. conorii,R. africae,and R. sibirica: Implications for rickettsial taxonomy

Rickettsia parkeri, a member of the spotted fever group rickettsias, was first described in 1939 and was thought to be non‐pathogenic until recently, when it was found to cause a spotted fever‐like illness in humans and areas of necrosis (eschars) at the sites of tick bites. Accordingly, there is currently much interest in this emerging pathogen. In this study, all published articles concerning R. parkeri were reviewed and analyzed for evidence of relatedness among this agent and other spotted fever group (SFG) rickettsiae which also produce similar clinical syndromes and/or eschars, including R. conorii, R. africae, and R. sibirica. A synthesis of the historical (antigenic) and recent (molecular) data supporting a phylogenetic sub‐grouping of these SFG organisms is presented and comments are offered about the taxonomy of rickettsial organisms in general, and R. parkeri in particular.     

The control of flower initiation by gibberellin in Helianthus annuus L. (sunflower), a non-photoperiodic plant

The involvement of gibberellins in the control of flowering of sunflower was studied by direct application of GA₃ to the apex of the plants, analysis of the endogenous levels of gibberellin-like substances at different plant ages, and indirectly by the application of paclobutrazol, an inhibitor of gibberellin synthesis. GA₃ speeded-up flower initiation and floral apex development. The time of GA₃ application was more critical than the amount of GA₃ applied. The endogenous levels of gibberellin-like compounds increased significantly by day 15 after sowing. The application of paclobutrazol markedly delayed floral initiation and this effect was also depedent on plant age. Both GA₃ and paclobutrazol had their greatest effects between 10 and 20 days after sowing suggesting that an increase in gibberellins in that time period plays a role in floral initiation.     

Trace elements in rock salt and their bioavailability estimated from solubility in acid

In this study, 18 partly commercially available samples of rock salt from Austria, Germany, Pakistan, Poland, Switzerland, and Ukraine were investigated with respect to their content of trace elements using instrumental neutron activation analysis. Elements detected were Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, La, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, and Zn, some of them only in individual cases. An estimation of the bioavailability of these trace elements was performed by dissolving an equivalent of the sodium chloride samples in diluted hydrochloric acid (simulating stomach acid), filtering off the insoluble components, and analyzing the evaporated filtrate. It could be shown that in most cases bioactive trace elements like Fe can be found in rock salt in the form of almost insoluble compounds and are therefore not significantly bioavailable, whereas thorium, for example, was partly bioavailable in two cases. A significant contribution to the recommended daily intake of metal trace elements by using rock salt for nutrition can be excluded.     

Phosphorylation and ubiquitination of dynamin-related proteins (AtDRP3A/3B) synergically regulate mitochondrial proliferation during mitosis

The balance between mitochondrial fission and fusion is disrupted during mitosis, but the mechanism governing this phenomenon in plant cells remains enigmatic. Here, we used mitochondrial matrix‐localized Kaede protein (mt‐Kaede) to analyze the dynamics of mitochondrial fission in BY‐2 suspension cells. Analysis of the photoactivatable fluorescence of mt‐Kaede suggested that the fission process is dominant during mitosis. This finding was confirmed by an electron microscopic analysis of the size distribution of mitochondria in BY‐2 suspension cells at various stages. Cellular proteins interacting with Myc‐tagged dynamin‐related protein 3A/3B (AtDRP3A and AtDRP3B) were immunoprecipitated with anti‐Myc antibody‐conjugated beads and subsequently identified by microcapillary liquid chromatography–quadrupole time‐of‐flight mass spectrometry (CapLC Q‐TOF) MS/MS. The identified proteins were broadly associated with cytoskeletal (microtubular), phosphorylation, or ubiquitination functions. Mitotic phosphorylation of AtDRP3A/AtDRP3B and mitochondrial fission at metaphase were inhibited by treatment of the cells with a CdkB/cyclin B inhibitor or a serine/threonine protein kinase inhibitor. The fate of AtDRP3A/3B during the cell cycle was followed by time‐lapse imaging of the fluorescence of Dendra2‐tagged AtDRP3A/3B after green‐to‐red photoconversion; this experiment showed that AtDRP3A/3B is partially degraded during interphase. Additionally, we found that microtubules are involved in mitochondrial fission during mitosis, and that mitochondria movement to daughter cell was limited as early as metaphase. Taken together, these findings suggest that mitotic phosphorylation of AtDRP3A/3B promotes mitochondrial fission during plant cell mitosis, and that AtDRP3A/3B is partially degraded at interphase, providing mechanistic insight into the mitochondrial morphological changes associated with cell‐cycle transitions in BY‐2 suspension cells.