English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The interaction between Fe requirements and N metabolism in centric diatoms was investigated to determine whether use of nitrate (NO3-) imparts a higher cellular Fe demand for growth than use of ammonlunl (NHdC), and thus reduces fitness under Fe deficiency. SIX species of the genus Thalassiosira from a variety of habitats were examined. Coastal and central gyre representat~ves grew faster in Fe-sufficient media containing NH,', but isolates from the equatorial Pacific, an oceanic highnutrient, low-biomass region, achieved maximum rates with NO3Iron quotas ranged from 26 to 102 pm01 Fe mol-' C and were not affected in a predictable manner by N source or habitat. Relative growth rates were diminished in Fe-deficient media, particularly in coastal species which grew at less than 25% of thelr maximum rates (pmdr). All oceanic species maintained fast rates of growth (0.8 p,,,) under the same Fe-limiting conditions, despite having 4 times less intracellular Fe than the coastal species. Fe:C ra t~os of Fe -de f~c~en t Thalassios~ra spp. ranged from 0.7 to 14 pm01 mol'] and were significantly greater (by 1.8 times) in all species when N O 3 was the N source (p < 0.05). Steady-state Fe uptake rates were also faster in NO3dependent cells a t low Fe. Nitrogen source had different effects on Fe-limited growth rates. Surprisingly, T oceanica (clone 1003) and T weissflogii grew faster with NO3even though higher Fe requirements for use of oxid~zed N were expected to reduce d~vision rates relative to NH,+-grown cells. When total Fe concentrations In the medlum were decreased to 1 nM, growth rates of T oceanjca (clone 1003) decreased to 0.2 p,,, and were s~gn~ficant ly faster (25%) in NHdt than in NO3--amended media. Under these more stressful Fe-limiting conditions, Fe quotas were the same in cells cultured in both N-based media. Our results thus demonstrate that phototrophic phytoplankton require significantly more cellular Fe to grow on NO3than NH,' Nitrate-grown cells are able to obtain this extra Fe, even when Fe is limiting, suggesting that Fe acquisition 1s somehow linked to NO,metabolism. Under severe Fe deficiency, however, NO,utilization reduces division rates compared to NHdt, because cells are unable to fulfil1 their extra Fe requ~rements .

Influence of N substrate on Fe requirements of marine centric diatoms