The antifungal effects of 16 ground herbs and spices, 4 other plant materials, 3 commercial antifungal agents, tannic acid and 2 experimental mold inhibitors were tested against seven mycotoxin- producing molds. Of the 26 substances tested, cloves, cinnamon, mustard, allspice, garlic, and oregano at the 2% level in potato dextrose agar, completely inhibited growth of all seven mycotoxigenic molds for various times up to 21 d. The remaining compounds either caused little or no inhibition. Powdered pomegranate peel was a good inhibitor against four Penicillium species. Potassium sorbate at 0.3% was highly effective against all seven mold strains. The antifungal antibiotic, natamycin (pimaricin), was also highly effective. Combinations of different levels of potassium sorbate and cloves showed an enhanced or possible synergistic inhibitory effect on growth of all seven molds tested, indicating the possibility of using spices and commercial antifungal agents together in small amounts to obtain antimycotic activity.

Gut microbiota influence numerous aspects of host biology, including brain structure and function. Growing evidence implicates gut microbiota in aversive conditioning and anxiety-related behaviors, but research has focused almost exclusively on males. To investigate whether effects of gut dysbiosis on aversive learning and memory differ by sex, adult female and male C57BL/6N mice were orally administered a moderate dose of nonabsorbable antimicrobial medications (ATMs: neomycin, bacitracin, and pimaricin) or a control over 10 days. Changes in gut microbiome composition were analyzed by 16S rRNA sequencing. Open field behavior, cued aversive learning, context recall, and cued recall were assessed. Following behavioral testing, the morphology of basolateral amygdala (BLA) principal neuron dendrites and spines was characterized. Results revealed that ATMs induced gut dysbiosis in both sexes, with stronger effects in females. ATMs also exerted sex-specific effects on behavior and neuroanatomy. Males were more susceptible than females to microbial modulation of locomotor activity and anxiety-like behavior. Females were more susceptible than males to ATM-induced impairments in aversive learning and cued recall. Context recall remained intact, as did dendritic structure of BLA principal neurons. However, ATMs exerted a sex-specific effect on spine density. A second experiment was conducted to isolate the effects of gut perturbation to cued recall. Extinction was also examined. Results revealed no effect of ATMs on cued recall or extinction, suggesting that gut dysbiosis preferentially impacts aversive learning. These data shed new light on how gut microbiota interact with sex to influence aversive conditioning, open field behavior, and BLA dendritic spine architecture.

Keywords: antibiotics; dendritic spines; estrous; fear conditioning; gut microbiome; gut-brain axis.