Pressure Resin Infiltration of Aphids for Electron Microscopy

Fixed, dehydrated pea aphids, Acyrthosiphon pisum Harris, were partially infiltrated with epoxy resins by standard procedures, then placed in a pressure chamber at up to 1000 psi for varying lengths of time. Insects so treated were found to be more suitable than nonpressurized insects for ultrathin sectioning and electron microscopy.

It was necessary to remove one or more legs from the insects to obtain adequate infiltration even where high pressures were employed. Little damage was evident at light or electron microscope levels of examination.     

Evaluation of trichothecene and nontrichothecene mycotoxins produced byFusarium in soybeans

Each of 12 cultures ofFusarium, comprising four species, isolated from moldy soybeans suspected of being involved in illness of wild geese, were grown separately in autoclaved moist rice, in autoclaved moist soybeans, and in surface sterilized-disinfected soybeans, assayed for various mycotoxins, and fed to rats. Four additional cultures that produced known toxins on rice were also grown on soybeans as controls. All isolates, except one ofF moniliforme, grown in rice resulted in weight loss of rats, and that one resulted in weight gain; 12 of the isolates caused death. One isolate ofF poae grown in soybeans caused death when consumed by rats, but none of the other 15 resulted in weight loss or overt injury. Much larger amounts of zearalenone, deoxynivalenol (DON), T-2 toxin, neosolaniol, T-2 tetraol, wortmannin, and moniliformin were produced by the cultures on rice than on soybeans, but more HT-2 toxin was produced by one isolate ofF poae grown on soybeans than when grown on rice. Soybeans appear to be a poor substrate for elaboration of most of the toxins produced by the isolates tested.