Use of Lilium longiflorum, cv. ace pollen germination and tube elongation as a bioassay for the hepatocarcinogens, aflatoxins.

Although various animal tissues are used for bioassay of aflatoxins (B1, B2, G1, G2), a rapid bioassay dependent upon a plant part's response does not exist. Both pollen germination (G) and tube elongation (TE) were enhanced in a 3.0 mM KH2PO4 (K)-containing but AFB1-lacking, modified Dickinson's medium. The B1 did not affect G when K was withheld but K supplementation impaired G above 15 micrograms/ml B1. Without K, 5-20 stimulated but 25 and 30 micrograms/ml B1 inhibited TE which was suppressed by every B1 conc tested in K-containing medium. Addition of NaH2PO4(N) instead of K to medium did not promote G. Slight G stimulation occurred at 16.6 micrograms/ml mixed aflatoxins (MA) in medium lacking either K or N but low G inhibitions were observed with K or N. The MA at 33.3 micrograms/ml reduced G 2.5% in K's of N's absence and 26 or 17% in their presence. While K did not stimulate TE without MA, N did 26%. At 16.6 and 33.3 micrograms/ml MA, TE was reduced 19, 6, 19% and 24, 25, 31%, respectively, in control, K- and N- media. Pollen G and TE were markedly sensitive to G1. Significant inhibitions of Zea mays seed G were observed at 5.8 and 11.6 micrograms/ml B1 but not root elongation (RE) from 0.4-11.6 micrograms/ml. The MA (31.5 micrograms/ml) administered for 72-240 hr did not influence either Arachis hypogeae seed G or RE. However, imbibing 5 cultivars each of Avena sativa (65-117 hr) and Hordeum vulgare (39-89 hr) inhibited RE 4/15-62%. Thus, except for Z. mays, pollen G and TE appear to be more B1-sensitive than seed G and RE. But, the pollen bioassay is less sensitive than both certain animal bioassays (0.025 micrograms/ml) and analytical methodologies (10 pg.)

Carbohydrate and protein contents of grain dusts in relation to dust morphology.

Grain dusts contain a variety of materials which are potentially hazardous to the health of workers in the grain industry. Because the characterization of grain dusts is incomplete, we are defining the botanical, chemical, and microbial contents of several grain dusts collected from grain elevators in the Duluth-Superior regions of the U.S. Here, we report certain of the carbohydrate and protein contents of dusts in relation to dust morphology. Examination of the gross morphologies of the dusts revealed that, except for corn, each dust contained either husk or pericarp (seed coat in the case of flax) fragments in addition to respirable particles. When viewed with the light microscope, the fragments appeared as elongated, pointed structures. The possibility that certain of the fragments within corn, settled, and spring wheat were derived from cell walls was suggested by the detection of pentoses following colorimetric assay of neutralized 2 N trifluoroacetic acid hydrolyzates of these dusts. The presence of pentoses together with the occurrence of proteins within water washings of grain dusts suggests that glycoproteins may be present within the dusts. With scanning electron microscopy, each dust was found to consist of a distinct assortment of particles in addition to respirable particles. Small husk fragments and "trichome-like" objects were common to all but corn dust