Cryptic polychaete diversity: a review

This review summarises the current knowledge on cryptic species of polychaetes, one of the most dominant taxa in marine communities, and gives a brief overview of the different methods that has been used for their disclosure. Cryptic species constitute an important part of biodiversity and they are common among all kinds of polychaetes, with different life history traits, and may have sympatric as well as allopatric distributions. It is emphasised that cryptic species must not be neglected for a variety of reasons, and even though the magnitude of cryptic species is largely unknown the available data on polychaetes clearly demonstrate that morphology alone seriously underestimate the number of species. It is suggested that future research should focus on appropriately designed case‐studies using combined approaches, as well as on large‐scale whole sample analyses using next‐generation sequencing in order to be able to answer the many questions that still remains.     

Tree roots as self-similar branching structures: axis differentiation and segment tapering in coarse roots of three boreal forest tree species

We applied a fractal root model to the 3D architecture of the coarse root systems of Betula pendula Roth, Picea abies (L.) H. Karst., and Pinus sylvestris L. in mixed boreal forests. Our dataset consisted of 60 root systems excavated in five different mixed forest stands. We analyzed the variability of the model parameters with respect to species, site type, and different root axes. According to our results, the cross-sectional area of root segments (i.e. second power of diameter) was a suitable variable for analyzing the values of parameters of the fractal model. The parameter values varied with generation and order of root segments; the roots thus did not follow the simple fractal branching. The variation of parameters along the root axes showed the existence of a zone of rapid tapering in all tree species. The model was, with parameter values analyzed from the data, moderately capable of accounting for the main coarse root characteristics. It was important for model predictions to take into account the tapering of root segments. We conclude that, in boreal forests, tree root systems are the output of the axis-specific morphogenetic branching rules and functional adaptation to spatial heterogeneity in the soil.     

A diffusion limited reaction theory for a solid-phase immunoassay

Theoretical calculations are presented, describing the kinetics of a solid-phase immunoassay where reactants are allowed to diffuse through a gel wedge in the bottom of a circular basin. The analysis is based on the assumption of a diffusion rate limited reaction at the underlaying surface. The influence of initial concentration, incubation time, temperature and the effect of stirring are predicted by the theoretical model. Experimental data are found to follow the theoretical model with parameters consistent with previous values.     

Effects of metabolic inhibitors on the distribution of 45-Ca in subcellular fractions from pancreatic islets

It is well established that intracellular calcium buffering is of vital importance for the regulation of insulin release. The metabolic inhibitors, cyanide and N-ethylmaleimide, both decreased the 45-Ca content of a mitochondrial fraction isolated from glucose-stimulated pancreatic islets. We suggest that the main mechanism behind this decrease is an impaired uptake of the isotope, since cyanide had no effect on the 45-Ca wash-out from the mitochondrial fraction of preloaded islets.