Premature translation of protamine 1 mRNA causes precocious nuclear condensation and arrests spermatid differentiation in mice.

Translational control is a major form of regulating gene expression during gametogenesis and early development in many organisms. We sought to determine whether the translational repression of the protamine 1 (Prm1) mRNA is necessary for normal spermatid differentiation in mice. To accomplish this we generated transgenic animals that carry a Prm1 transgene lacking its normal 3' untranslated region. Premature translation of Prm1 mRNA caused precocious condensation of spermatid nuclear DNA, abnormal head morphogenesis, and incomplete processing of Prm2 protein. Premature accumulation of Prm1 within syncytial spermatids in mice hemizygous for the transgene caused dominant male sterility, which in some cases was accompanied by a complete arrest in spermatid differentiation. These results demonstrate that correct temporal synthesis of Prm1 is necessary for the transition from nucleohistones to nucleoprotamines.

Biometry, stable isotopes and stomach contents of A. glacialis and B. saida from Northeast Greenland

Two gadoid fishes, Arctogadus glacialis and Boreogadus saida, often coexist (i.e. sympatric) in the fjords and shelf areas of the Arctic seas, where they likely share the same food resources. Diet composition from stomach contents, i.e. frequency of occurrence (FO) and Schoener's index (SI), and stable isotope signatures (d13C and d15N) in muscle of these sympatric gadoids were examined from two fjords in NE Greenland-Tyrolerfjord (TF, ~74°N, sill present) and Dove Bugt (DB, ~76°N, open). Twenty-three prey taxa and categories were identified and both gadoids ate mostly crustaceans. The SI values of 0.64-0.70 indicated possible resource competition, whereas FO differed significantly. A. glacialis fed mainly on the mysid Mysis oculata and other benthic-associated prey, whereas B. saida ate the copepod Metridia longa and other pelagic prey. Both diet and stable isotopes strongly suggest a spatial segregation in feeding habitat, with A. glacialis being associated with the benthic food web (mean d13C = -20.81 per mil, d15N = 14.92 per mil) and B. saida with the pelagic food web (mean d13C = -21.25 per mil, d15N = 13.64 per mil). The dietary differences and isotopic signals were highly significant in the secluded TF and less clear in the open DB, where prey and predators may be readily advected from adjacent areas with other trophic conditions. This is the first study on the trophic position of A. glacialis inferred from analyses of stable isotopes. The subtle interaction between the Arctic gadoids should be carefully monitored in the light of ocean warming and ongoing invasions of boreal fishes into the Arctic seas.

Studier over de danske søers plankton,

Added t.p. in English: Plankton investigations of the Danish lakes.

Die Vögel der Schwedischen Südpolar-Expedition /

Mode of access: Internet.

Analytic function theory.

Includes bibliographies.

Apterygoten aus Ägypten und dem Sudan nebst Bemerkungen zur Verbreitung und Systematik der Collembolen,

Cover-title.

Contributions to the fauna of South Georgia.

Mode of access: Internet.

On the theory of social change: how economic growth begins.

Includes bibliography.

Der Kaiser und die Monarchisten /

Mode of access: Internet.

Sögur Noregs konúnga frá Magnúsi Berfætta til Magnúss Erlíngssonar.

Edited by R. K. Rask.

Norges konge-sagaer fra Magnus Barfod til Magnus Erlingsøn,

Kong Magnus Barfods saga.--Kong Sigurd Jorsalafarers og hans brødre Eistens og Olafs saga.--Kong Harald Gilles og Magnus den Blindes saga.--Kong Inge Haraldsøns og hans brødres saga.--Kong Hakon Haerdebreds saga.--Kong Magnus Erlingsøns saga. Om Einar Skulesøn.--Gregorii forste faerd.