Requirement of a Membrane Potential for the Posttranslational Transfer of Proteins into Mitochondsria

Posttranslational transfer of most precursor proteins into mitochondria is dependent on energization of the mitochondria. Experiments were carried out to determine whether the membrane potential or the intramitochondrial ATP is the immediate energy source. Transfer in vitro of precursors to the ADP/ATP carrier and to ATPase subunit 9 into isolated Neurospora mitochondria was investigated. Under conditions where the level of intramitochondrial ATP was high and the membrane potential was dissipated, import and processing of these precursor proteins did not take place. On the other hand, precursors were taken up and processed when the intramitochondrial ATP level was low, but the membrane potential was not dissipated. We conclude that a membrane potential is involved in the import of those mitochondrial precursor proteins which require energy for intracellular translocatio

Cryptic species in a well-known habitat: applying taxonomics to the amphipod genus Epimeria (Crustacea, Peracarida)

Taxonomy plays a central role in biological sciences. It provides a communication system for scientists as it aims to enable correct identification of the studied organisms. As a consequence, species descriptions should seek to include as much available information as possible at species level to follow an integrative concept of ‘taxonomics’. Here, we describe the cryptic species Epimeria frankei sp. nov. from the North Sea, and also redescribe its sister species, Epimeria cornigera. The morphological information obtained is substantiated by DNA barcodes and complete nuclear 18S rRNA gene sequences. In addition, we provide, for the first time, full mitochondrial genome data as part of a metazoan species description for a holotype, as well as the neotype. This study represents the first successful implementation of the recently proposed concept of taxonomics, using data from highthroughput technologies for integrative taxonomic studies, allowing the highest level of confidence for both biodiversity and ecological research

Nucleotide sequences of the genes encoding fructosebisphosphatase and phosphoribulokinase from Xanthobacter flavus H4-14

The genes encoding fructosebisphosphatase and phosphoribulokinase present on a 2.5 kb SalI fragment from Xanthobacter flavus H4-14 were sequenced. Two large open reading frames (ORFs) were identified, preceded by plausible ribosome-binding sites. The ORFs were transcribed in the same direction and were separated by 39 base pairs. They encoded proteins of 364 and 291 amino acids, with molecular masses of 38739 and 33409 Da, respectively. The ORFs were identified as the genes encoding FBPase and PRK, respectively, on the basis of similarity with FBPase and PRK sequences from other sources.

Chimerism as the basis for the occurrence of amylose synthesizing clones derived from an amylose-free potato mutant

Earlier described revertants, obtained after irradiation of an amylose-free (amf) mutant which carries a point deletion in the gene for granule-bound starch synthase, were analysed at the DNA-sequence level. Direct sequencing of fragments amplified by the polymerase chain reaction revealed that all investigated revertants carry the original wildtype sequence. It is argued that mutation as the basis for the re-occurrence of wildtype alleles is highly unlikely. The alternative conclusion is reached that the original amylose-free monoploid clone must have been a chimera. Chimerism with wildtype and mutant tissues was actually found in a plant which at a later stage was obtained from the same mutant clone without the use of X-rays. Wildtype cells could have remained in the L2 layer of the original monoploid mutant, which cannot be analyzed for starch composition

Small villages and socio-economic change in resource peripheries: A view from Northern Sweden

Many towns and villages in the inland north of Sweden were settled by independent farmers and foresters, with industry and company towns being relatively rare. In Canada and Australia industry and company towns were more common, and there is some evidence that those towns have found it more difficult to attract and retain population than what we term here as ‘settler towns’. Development of alternative economic activities such as tourism has been difficult. In Sweden, however, there is no clear distinction between the recent demographic performance of industry and settler villages, and local economic activity has been relatively unimportant as most villages are well connected to regional labour markets