SUMMARY: The objective of this study was to investigate the mechanism of prenatal stress on the cognitive function of offspring, and clarify the change of histone deacetylase 2 (HDAC2) expression in hippocampal neurons of offspring. 16 pregnant SD rats were randomly divided into control group and stress group, with eight rats in each group. The stress group received restrained stress from 15 to 21 days of pregnancy, while the control group did not receive any treatment. Anxiety-like behavior and spatial memory, learning and memory ability were detected in open field, elevated plus maze, novel object recognition test, and Barnes maze. Nissl staining was used to detect the function of hippocampal neurons. Western blot was used to detect the expression of HDAC2 protein in hippocampal neurons of adult offspring. Immunofluorescence staining was used to detect the expression of HDAC2 protein and hippocampal neurogenesis. The learning and memory ability of adult offspring was decreased. The prenatal stress damaged the function of hippocampal neurons , the expression of HDAC2 was down-regulated, and the number of neurons was reduced. Maternal prenatal stress can down- regulate the expression of HDAC2 in the hippocampus of offspring, inhibits hippocampal neurogenesis and impairs the cognitive function.

RESUMEN: El objetivo de este estudio fue investigar el mecanismo del estrés prenatal en la función cognitiva de la descendencia y aclarar el cambio de la expresión de la histona desacetilasa 2 (HDAC2) en las neuronas del hipocampo de la descendencia. 16 ratas SD preñadas se dividieron aleatoriamente en un grupo de control y un grupo de estrés, con ocho ratas en cada grupo. El grupo de estrés recibió estrés durante 15 a 21 días de pre, preñez, mientras que el grupo de control no recibió ningún tratamiento. El comportamiento similar a la ansiedad y la memoria espacial, el aprendizaje y la capacidad de memoria se detectaron en campo abierto, laberinto en cruz elevado, prueba de reconocimiento de objetos novedosos y laberinto de Barnes. La tinción de Nissl se utilizó para detectar la función de las neuronas del hipocampo. Se utilizó Western blot para detectar la expresión de la proteína HDAC2 en las neuronas del hipocampo de la descendencia adulta. La tinción de inmunofluorescencia se utilizó para detectar la expresión de la proteína HDAC2 y la neurogénesis del hipocampo. La capacidad de aprendizaje y memoria de la descendencia adulta se redujo. El estrés prenatal dañó la función de las neuronas del hipocampo, se reguló negativamente la expresión de HDAC2 y se redujo el número de neuronas. El estrés prenatal materno puede regular a la baja la expresión de HDAC2 en el hipocampo de la descendencia, inhibe la neurogénesis del hipocampo y deteriora la función cognitiva.

Abstract Impacts of high hydrostatic pressure (HHP) pretreatment on the physicochemical, functional and antioxidant properties of soybean protein isolate (SPI) were investigated. Changes in the secondary and tertiary structures were determined by Fourier transform infrared spectra and fluorescence spectra. The particle sizes reduced from 217.20 nm to 192.70 nm while the zeta potential increased. It’s revealed by scanning electron microscopy that the HHP treatment could result in the formation of large aggregation, leaving the SPI with irregular and uneven surface. Moreover, hollow spheres were also observed in SPI by means of dynamic and static light scattering. As a result, the foaming capacity of HHP-treated SPI and antioxidant activity of the HHP-treated SPI hydrolysates were improved significantly.

The effects of the expression of a small heat shock protein (shsp) gene from Streptococcus thermophilus on stress resistance in Lactococcus lactis under different environmental stresses were investigated in this study. pMG36e-shsp, an expression vector, was first constructed by inserting a shsp open reading frame (ORF) cloned from S. thermophilus strain St-QC into pMG36e. Then, a food-grade expression vector, pMG-shsp, was generated by deleting the erythromycin resistance gene from pMG36e-shsp. The transformation rate of pMG-shsp was comparable to that of pMG36e-shsp when each of these two vectors was introduced into L. lactis. These results demonstrated that the shsp ORF could successfully used as a food-grade selection marker in both pMG-shsp and pMG36e-shsp. Furthermore, the growth characteristics were almost the same between L. lactis ML23 transformants harboring pMG36e or pMG-shsp. The survival rate of L. lactis ML23 expressing the shsp ORF were increased to 0.032%, 0.006%, 0.0027%, 0.03%, and 0.16% under the following environmental stresses: heat, acid, ethanol, bile salt and H2O2, respectively. These results indicated that the expression of the shsp gene in the food-grade vector pMG-shsp conferred resistance to environmental stresses without affecting the growth characteristics of L. lactis ML23.