Distribution and habitat preference of Bombus (Kallobombus) soroeensis (Fabricius, 1777) on the territory of Arkhangelsk Region

In this paper, we summarise material pertaining to the distribution and habitat preference of Bombus (Kallobombus) soroeensis (Fabricius, 1777) on the territory of Arkhangelsk Region. B. soroeensis is widely represented on the territory as nominative subspecies B. soroeensis ssp. soroeensis, which is common mainly in Fennoscandia, the British Isles and Eastern Europe. The northern border of the species range in the Arkhangelsk Region is the lower reaches of the Mezen River, located in the transition zone between the northern taiga and the forest-tundra. This locality is probably one of the most northern records of this species in the northern part of the Russian Plain. In Eastern Fennoscandia, B. soroeensis is distributed far to the north, i.e., in the northern parts of Finland and Norway. In relation to the habitat preference, B. soroeensis in the study region belongs to the category of meadow species. This species is typical of different types of meadows and ruderal habitats. B. soroeensis is not typical with regards to the native taiga habitats, in most cases. This is similar to the situation on the territory of Finland, where this species is associated with open meadow habitats. Individuals of B. soroeensis have been recorded on a wide range of entomophilous plants, and the main examples are Rhinanthus minor, Epilobium angustifolium, Cirsium arvense, Scorzoneroides autumnalis, Lotus corniculatus

Contribution of inter-subunit interactions to the thermostability of Pyrococcus furiosus citrate synthase

Using citrate synthase from the hyperthermophile Pyrococcus furiosus (PfCS) as our test molecule, we show through guanidine hydrochloride-induced unfolding that the dimer separates into folded, but inactive, monomers before individual subunit unfolding takes place. Given that forces across the dimer interface are vital for thermostability, a robust computational method was derived that uses the University of Houston Brownian Dynamics (UHBD) program to calculate both the hydrophobic and electrostatic contribution to the dimerisation energy at 100°C. The results from computational and experimental determination of the lowered stability of interface mutants were correlated, being both of the same order of magnitude and placing the mutant proteins in the same order of stability. This computational method, optimised for hyperthermophilic molecules and tested in the laboratory, after further testing on other examples, could be of widespread use in the prediction of thermostabilising mutations in other oligomeric proteins for which dissociation is the first step in unfolding