Polyols Induce the Production of Antifungal Compounds by Lactobacillus plantarum.

Mycotoxins may be present in nuts, coffee, cereals, and grapes, among other products. Increasing concerns about human health and environmental protection have driven the application of biological control techniques that can inhibit fungal contaminants. In this study, the growth inhibition of the ochratoxigenic fungus Aspergillus carbonarius Ac 162 was evaluated using 5 lactic acid bacteria (LAB). The LAB studied were Lactobacillus plantarum MZ801739 (J), Lactobacillus plantarum MZ809351 (31) and Lactobacillus plantarum MZ809350 (34), isolated in the Ivory Coast, and Lactobacillus plantarum MN982928 (3) and Leuconostoc citreum MZ801735 (23), isolated in Mexico. J, 31, 34, 3 and 23 are the internal strain codes from our laboratory. LAB were cultivated in De Man, Rogosa and Sharpe (MRS) broth, and different polyols (glycerol, mannitol, sorbitol, and xylitol) were added to the culture broth to stimulate the production of antifungal compounds. The fungal inhibition studies were performed using the poisoned food technique. The highest inhibition of A. carbonarius growth was obtained by cultivating L. plantarum MZ809351 in the presence of xylitol and glycerol. Under these conditions, 1 L of the L. plantarum MZ809351 cultures were used to identify antifungal compounds. The compounds were concentrated by solid-phase extraction and then characterized by GC-MS. In addition to 9-octadecenoic acid, 3 diketopiperazines or cyclic dipeptides were identified, including cyclo (Leu-Leu), cyclo (Pro-Gly) and cyclo (Val-Phe), which were compounds related to microbial antifungal activities. Xylitol and glycerol induced the production of these antifungal compounds against A. carbonarius Ac 162. On the other hand, adding xylitol and glycerol to the MRS broth reduced the Ochratoxin A (OTA) content to 56.8 and 54.7%, respectively. This study shows the potential for using L. plantarum MZ809351 as a biocontrol agent to prevent the growth of A. carbonarius and reduce the production of OTA in foods.

Sleep-EEG patterns of school children suffering from symptoms of depression compared to healthy controls.

Depression in children is often an elusive disorder and its diagnostic tools are a matter of controversy. Several scales have been developed in an attempt to specifically detect some of the major aspects of depression, i.e. anhedonia, sadness, hopelessness. On the other hand, in adults depression frequently induces changes in sleep patterns, particularly a shortening in REM sleep latency. The alteration of sleep patterns in depressed children has been a matter of controversy. It is possible that a diagnostic deficiency might be the source of the contradictory reports. In the present study, The Child Depression Inventory, a rating scale specifically developed for child depression was applied to 396 school children (8-12 years of age). Nearly 15% of the children (N = 45) obtained scores higher than the established limit in this test for normal healthy subjects. A sample of children found within the highest (N = 25) and within the lowest (N = 25) scores in the scale were selected. After a clinical evaluation, only those who meet the inclusion criteria (N = 21 for depressed and N = 7 for healthy controls) were electroencephalographically recorded. Children with depressive symptoms showed a significant shortening in REM sleep latency (mean = 108 min) when compared to non-depressed (mean = 150 min). In addition, significant increases were observed in sleep latency, REM sleep duration and the number of awakenings. Furthermore, results showed an unexpected high frequency of EEG abnormalities in children with depressive symptoms (75%) characterized by sharp waves and polyspikes in the frontal region. The present results support the notion that depression, in children, is accompanied by changes in sleep patterns, mainly concerning REM sleep.