Endoglucanase A from Cellulomonas fimi in which the hinge sequence of human IgA1 is substituted for the linker connecting its two domains is hydrolyzed by IgA proteases from Neisseria gonorrhoeae

The hinge in IgA1 and the linker in endoglucanase A (CenA) are quite similar. The IgA1 hinge is 18 amino acids long and contains only proline, threonine and serine. The linker in CenA is 27 amino acids long and contains only proline, threonine and a single serine. IgA proteases from Neisseria gonorrhoeae cleave Pro-Ser and Pro-Thr bonds within the IgA1 hinge sequence, but they do not attack CenA. When the linker sequence of CenA is replaced with the hinge sequence of IgA1, the hybrid polypeptide is susceptible to the N. gonorrhoeae proteases. It is cleaved within the hinge sequence at the same sites as IgA1.     

Not all droughts are created equal? The effects of stress severity on insect herbivore abundance

Predicting interactions between drought and plant–insect interactions has been a challenge. Currently, we are unable to accurately predict herbivore abundance on stressed plants despite over 500 publications and half a dozen formal hypotheses. With drought predicted to increase in severity with climate change, determining herbivore abundance on stressed plants is critical for continued agricultural and natural system management. During drought, plants increase concentrations of nutrients and also suffer from water loss. Many empirical studies test drought on plants using severe continuous stress, but studies suggest drought may benefit herbivores when it is intermittent (pulsed). In our study, we tested intermittent and severe stress on herbivore and arthropod abundance in a cotton agro-ecosystem. Our goal was to determine how these types of drought influence herbivore abundance on stressed plants and the relationship between herbivore abundance and stress-related nutrients. We found that intermittent and severe water-deficit stress had different effects on insect herbivores, signifying that drought severity influences herbivore abundance. Piercing–sucking herbivores such as thrips, stink bugs, and leafhoppers were more abundant on intermittently stressed plants than on severely stressed plants. Drought did not significantly affect chewing herbivores, and their abundance was inconsistent on stressed and well-watered plants. Furthermore, nutrient concentrations were similar between stressed and unstressed plants, but herbivore abundance was greater on intermittently stressed plants, suggesting that other physiological characteristics of stressed plants and herbivore feeding ecology must be considered. Our study suggests that the drought severity must be considered when predicting herbivore abundance on stressed plants.     

In-vitro cleavage of a fusion protein bound to cellulose using the soluble yscFs (Kex2) variant

Summary Intra- and extracellular metabolite concentrations were determined for hybridoma cells grown in tissue culture flasks in batch culture. Significant differences were found for intracellular lactate and amino acid concentrations depending on the culture medium. AB2-143.2 cells cultivated in Dulbecco's modified Eagle's (DME) medium supplemented with 50 mm lactate exhibited intracellular lactate and glutamine levels of 40 mm and 4 mm, respectively, whereas cells grown in standard DME medium had low intracellular glutamine and 20 mm lactate concentrations. For cells cultivated in medium supplemented with 6 mm pyruvate, intracellular lactate levels were estimated at approx. 40 mm, but these cells also showed an increased intracellular alanine concentration of 22 mm. The higher alanine pools probably result from increased transamination of pyruvate under these conditions.     

Global versus Local Changes in Upwelling Systems (Collection Colloques et séminaires)

Reviews in Fish Biology and Fisheries -