In the red alga Porphyra perforata, the level of chlorophyll fluorescence in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) decreased during illumination of the thallus. The results showed that: (a) this decay was related to the photooxidative activity of photosystem I; (b) Q, the primary electron acceptor of photosystem II, became oxidized during the decay of the fluorescence; ...

Scattered small stands of Nothofagus truncata occur in the upper Taramakau catchment, Arthur's Pass National Park, beyond the previously assumed range of the species in north Westland. Restricted to older soils on stable north to north-west slopes, the N. truncata stands are surrounded by N. fusca dominated forest and their upper altitudinal limits at 370-500 m border N. fusca-N. menziesii or N...

Bu çalışmada, Çankırı Havzası’nda 2018 yılında MTA Doğu Akdeniz Bölge Müdürlüğü tarafından kömür arama amaçlı olarak açılmış sondajlardan derlenen örnekler incelenmiştir. Eosen yaşlı birimlerde yapılmış olan sondajlardaki kırıntılı sedimanter örneklerin ostrakod faunası değerlendirilmiştir. Bölgede Lütesiyen sarımsı gri renkli, fosilli, kumtaşı, silttaşı, marn ve kireçtaşı litolojisinden oluşma...

Abstract Mutualisms are of fundamental ecological importance, but risk breaking down if one partner stops paying the costs yet still takes benefits interaction. To prevent such cheating, many mutualisms have mechanisms that lower fitness uncooperative symbionts, often termed host sanctions. In where interacting partners species-specific, we would expect to see coevolution levels sanctions and c...

Cabib and Leloir (2) isolated and characterized guanosine diphosphate (GDP) mannose from bakers’ yeast and postulated that this nucleotide may serve as a donor of mannose residues for the synthesis of polymers which are present in the yeast cell wall. The occurrence of GDP-mannose may be ubiquitous since it has been reported to be present in hen’s oviduct (3), the molds Penicillium chrysogenum ...

Cells of Porphyra perforata, a red marine alga, accumulate K in the absence of concomitant Na or Li extrusion while immersed in Li- or Mg-sea waters lacking Na. This suggests that the coupling observed between K and Na transport is facultative. No evidence is obtained for net extrusion of Li. Na efflux, with the concentration gradient, is facilitated by K and is proportional to the cellular Na ...