STUDIES OF MARINE PLANKTONIC DIATOMS:II. USE OF CYCLOTELLA NANA HUSTEDT FOR ASSAYS OF VITAMIN B₁₂ IN SEA WATER

Abstract

Cyclo~ella na?zn I-Iustedt, a small centric diatom requiring vitamin Blr, was tested as a potential assay organism for that vitamin. Dose-respo~lse curves, measured by optical density and cell count, showed a linear relation between gro\vth and BIZ concel~tration between 0 and a t least 2 kkg/rnl of the vitamin. Sincc the diatom is hardy, grows rapidly under a variety of conditions, and Inay be preserved for later esaminatio~l, it represents a ~~s e f u l assay organism for certain applications such as ocearlographic exploration.

DISTRIBUTION AND SIGNIFICANCE OF VITAMIN B12 AND THIAMINE IN THE SUBARCTIC PACIFIC OCEAN1

“…Vitamin B 12 was assayed with the marine diatom CycZoteZZu nuna Husted,t Strain 3H which is sensitive in the range of 0-2 pg B12/ml (Ryther and Guillard 1962 ) .…”

Interactions between Diatoms and Bacteria

“…Early studies suggested a strong correlation between vitamin depletion in seawater and diatom bloom termination (129,130). Cobalamin, or vitamin B 12 , is by far the most studied vitamin in relation to diatom requirements (32,50,152). Cobalamin is required in organisms lacking the cobalamin-independent methionine synthase, MetE.…”

Effect of bacteria on growth and biochemical composition of two benthic diatoms Halamphora coffeaeformis and Entomoneis paludosa

“…One of the most common interactions is the bacterial release of growth promoting factors such as vitamins that are needed by microalgae (e.g. cobalamin, thiamine and biotin) (Carlucci and Silberna, 1969;Croft et al, 2005;Haines and Guillard, 1974;Kazamia et al, 2012;Ryther and Guillard, 1962;Tang et al, 2010). By their role in the nitrogen cycle, bacteria (e.g.…”