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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #143122
Title: TRANSMEMBRANE PARTITIONING ON BORON AND OTHER ELEMENTS IN RAW 264.7 AND HL60 CELL CULTURES

Author
item RALSTON, NICHOLAS - UND-EERC
item Hunt, Curtiss

Submitted to: Biological Trace Element Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2003
Publication Date: 5/1/2004
Citation: Ralston, N.V., Hunt, C. 2004. Transmembrane partitioning of boron and other elements in RAW 264.7 and HL60 cell cultures. Biological Trace Element Research. 98(2):181-192.

Interpretive Summary: The trace element boron is needed by all higher plants for life and is beneficial in the health of several animals as well as humans. To help identify the molecules in the body that require boron for function, we determined whether cells in the body gather boron and store it internally. We put one kind of animal cell and one kind of human cell in different nutrient solutions and then added boron to see whether the cells would take up and store the boron. We found that cells do keep boron even when there is less boron in the fluid around the cells. This means that animal and human cells have internal molecules that can bind to boron or that they have a way of continuously pumping boron in from the outside.

Technical Abstract: The trace element boron is essential for all higher plants and is beneficial or established essential for several models of human nutrition. To help identify the biomolecules that require boron for function in humans, we determined whether intracellular boron is retained against a concentration gradient. Cells (Abelson leukemia virus BALB murine monocyte-macrophage RAW 264.7 [RAW] and HL60) and supplemented media (Dulbecco's Modified Essential Media [+ 10% Fetal Calf Serum] and Iscove's modified Dulbecco's medium [+ 5% fetal calf serum], respectively) were analyzed for mineral concentrations after culture and subculture. Special corrections were made for trapped extracellular media in cell pellets and endocytosed media. For RAW cells, the partitioning coefficients (PC; intracellular/extracellular ratios) were, in rank order: Mn, 110; Fe, 67; P, 65; Zn, 32; K, 15; Cu, 7.1; Mg, 4.3; B, 1.7; Ca, 0.4; Na, 0.3. For HL60 cells, the partitioning coefficients were, in rank order: Mn, 212; Zn, 211; P, 123; K, 21; Fe, 16; Mg, 11; B, 1.7; Ca, 0.8; Na, 0.3. Trapped extracellular media was estimated to be 6.7 ± 0.8%; trapped extracellular and endocytosed media together, 24.8 ± 0.3% of the mass within the isolated cell pellets. The partitioning coefficients indicate a positive gradient for intracellular accumulation of boron, zinc, phosphorus, manganese, magnesium, potassium, iron, and copper in RAW264.7 and HL60 cells. Specifically, the data indicate existence of a selective boron-binding molecular species within the cell or the existence of boron specific membrane transporter.