224 BELSER 



Table II 

 Vitamin B12 Assay Organisms and Their Response Patterns 



[chap. 9 



a Mammalian = Response to cyanocobalamin only. Lb. leichmannii = Response to 

 cyanocobalamin, pseudo B12, factors A, Ci and C2. E. coli = Response to most known 

 analogues. 



b This table was prepared by the individuals listed in the right column during a round 

 table discussion of Vitamin B12 bioassay at the 1st International Oceanographic Congress, 

 1959, New York. 



(1956) reports values from 0.1 fi.[xg/ml in summer to 0.5-1.0 y.y.g/m\ in autumn. 

 Daisley and Fisher (1958) examined variation in concentration with depth, in 

 the Bay of Biscay, and found marked variability with depth, with the lowest 

 values in the upper euphotic zone. They report a concentration range from 

 0.3-4 fx[j.g/ml in a 3600-m vertical cast, using a Euglena gracilis assay. Vishniac 

 and Riley (1959) have reported similar seasonal variability in B12 in Long 

 Island Sound, ranging from 4.5 fxjjig/ml to greater than 12 ^{xg/ml over a period 

 of one year. Their assays were carried out with Thraustochrytrium globosum. 

 Kashiwada et al. (1959) also found variability in concentration of B12 both 

 horizontally and vertically in sea- water samples. They report values ranging 

 from 0.0 to 26.3 {ijAg/ml. 



Practically every sample subjected to assay by any of these techniques has 

 proven to contain some vitamin B12 activity. It is interesting to note that 

 characteristic of each of these investigations is a discontinuous distribution in 

 concentration of vitamin B12 both horizontally and vertically with marked 

 seasonal variability. This characteristic seems to hold for most other organic 

 micronutrients that have been studied. 



Other vitamins that have been assayed in sea-water samples include thiamine, 

 niacin and biotin. Provasoli and Gold (1959) have used one organism Gyro- 

 dinium cohnii to bioassay for both biotin and thiamine. This alga shows a linear 

 response to biotin between 3 and 40 [Xfj.g/ml and to thiamine between 100 and 

 4000 (j.[xg/ml. The organism requires a rather complex mixture of trace metals 



