Congruence between cytochrome oxidase I (COI) and morphological data in Anuraphis spp. (Hemiptera,Aphididae) with a comparison between the utility of the 5’ barcode and 3’ COI regions

The discrimination of species in the genus Anuraphis is particularly difficult due to the overlap of morphological characters. In this study, we used the 5’ (barcode) and 3’ regions of cytochrome oxidase I (COI) to test their utility in the identification of species in this genus as well as closely related species. Both regions were useful to discriminate all the species tested. However the non-barcode 3’ region resulted in higher resolution and support for species relationships when the data were analyzed using both Maximum Likelihood and MrBayes. We propose the development of an integrated database that encompasses morphological, molecular, life-cycle, host plant and bibliographic information to facilitate and increase the accuracy of aphid identification.     

Motility Enhancement through Surface Modification Is Sufficient for Cyanobacterial Community Organization during Phototaxis

The emergent behaviors of communities of genotypically identical cells cannot be easily predicted from the behaviors of individual cells. In many cases, it is thought that direct cell-cell communication plays a critical role in the transition from individual to community behaviors. In the unicellular photosynthetic cyanobacterium Synechocystis sp. PCC 6803, individual cells exhibit light-directed motility (“phototaxis”) over surfaces, resulting in the emergence of dynamic spatial organization of multicellular communities. To probe this striking community behavior, we carried out time-lapse video microscopy coupled with quantitative analysis of single-cell dynamics under varying light conditions. These analyses suggest that cells secrete an extracellular substance that modifies the physical properties of the substrate, leading to enhanced motility and the ability for groups of cells to passively guide one another. We developed a biophysical model that demonstrates that this form of indirect, surface-based communication is sufficient to create distinct motile groups whose shape, velocity, and dynamics qualitatively match our experimental observations, even in the absence of direct cellular interactions or changes in single-cell behavior. Our computational analysis of the predicted community behavior, across a matrix of cellular concentrations and light biases, demonstrates that spatial patterning follows robust scaling laws and provides a useful resource for the generation of testable hypotheses regarding phototactic behavior. In addition, we predict that degradation of the surface modification may account for the secondary patterns occasionally observed after the initial formation of a community structure. Taken together, our modeling and experiments provide a framework to show that the emergent spatial organization of phototactic communities requires modification of the substrate, and this form of surface-based communication could provide insight into the behavior of a wide array of biological communities.     

Dendrogeomorphological analysis of shore erosion along Bolsena lake (Central Italy)

Dendrogeomorphological research was conducted along a volcanic caldera lake of Bolsena in central Italy, Latium region, in order to investigate the erosion process that affects its coastline. Most of the trees sampled were black poplars (Populus nigra L.) with root systems differently exposed. The cores taken from trunks show growth stress (suppression) at different times according to the distance of the tree from the shoreline. Results of the morphological analysis of the root systems were used as a qualitative estimate of the erosion process developing an erosion map of the lake's shoreline. The dating of suppressions was used to calculate the main horizontal erosion rate at different shoreline sectors. The most intense erosion was recorded on the southern and northern shore, affected by the strongest and long-lasting winds (mean erosion rate at southern coast=0.092 m/year, northern coast=0.064 m/year, eastern coast=0.049 m/year, western coast=0.028 m/year). The age of the living trees along the shore points out that the erosion started at least in the 1970s (one of the highest lake level episode) and it is still in progress.     

Endothelin-1 drives invadopodia and interaction with mesothelial cells through ILK

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A simple assay for the quantitative evaluation of Phospholipase D activity

Summary We describe the preparation of phosphatidyl p-nitrophenol (PpNP) and its use as a substrate in an assay for the quantitative evaluation of Phospholipase D. The solution of the substrate in Tris HCl buffer, pH 8, and Triton X is mixed directly with an aliquot of fermentation broth and the absorbance of the solution read at 405 nm. The method is rapid, sensitive and inexpensive.