Sockeye salmon (Oncorhynchus nerka) stocks throughout the southern part of their North American range have experienced declines in productivity over the past two decades. In this study, we tested the hypothesis that pink (O. gorbuscha) and chum (O. keta) salmon stocks have also experienced recent declines in productivity by investigating temporal and spatial trends in productivity of 99 wild No...

HIGHLIGHTSIn an abortive ovary of hazel, an integument seldom differentiated and a mature embryo sac never developed.In an abortive ovary of hazel, pollen tube growth was arrested at the style base about 40 days after blooming. Thus, fertilization of the ovule was precluded.Ovary abortion in the four hybrid cultivars was indicated to be associated with insufficient resource availability to supp...

Transcription initiation at the sigma 54-dependent glnAp2 promoter was studied to follow the state of polymerase as RNA synthesis begins. Sigma 54 polymerase begins transcription in abortive cycling mode, i.e. after the first bond is made, approximately 75% of the time the short RNA is aborted and synthesis must be restarted. Polymerase is capable of abortive initiation until it reaches a posit...

A mating type transformation, involving cell-to-cell contact (abortive conjugation) insyngen 4 of Parameciwn bursaria has been investigated. By autoradiography, transfer of material between the conjugants in normal and abortive conjugation has been shown to occur. The transfer of this material, which includes protein, RNA and DNA, during abortive conjugation has been shown to be necessary if th...