[Effect of inhibiting miR-204 expression on the learning and memory abilities of neonatal rats with intrauterine growth restriction and related mechanism]. / 抑制miR-204è¡¨è¾¾å¯¹å®«å† å‘è‚²è¿Ÿç¼“æ–°ç”Ÿå¤§é¼ å­¦ä¹ è®°å¿†èƒ½åŠ›çš„å½±å“åŠç›¸å ³æœºåˆ¶.

OBJECTIVES: To investigate the effect of inhibiting miR-204 expression on the learning and memory abilities of neonatal rats with intrauterine growth restriction (IUGR) and related mechanism. METHODS: A rat model of IUGR was prepared by low-protein diet. The 3-day-old IUGR rats were divided into three groups: model, miRNA antagonist control and miR-204 antagonist, with 10 rats in each group. Ten normal neonatal rats served as the control group. Morris water maze test was used to measure the learning and memory abilities of the rats. Quantitative real-time PCR was used to measure the mRNA expression levels of miR-204 and brain-derived neurotrophic factor (BDNF) in the hippocampus. Nissl staining and TUNEL staining were used to observe the number of Nissl bodies and the apoptosis of cells in the hippocampus. Western blot was used to measure the expression levels of BDNF/TrkB signaling pathway-related proteins in the hippocampus. RESULTS: Compared with the control group, the model group had a significant increase in the escape latency and a significant reduction in the number of platform crossings (P<0.001). The model group also had significant increases in the apoptosis rate of cells and the expression level of miR-204 in hippocampal tissue (P<0.001), while the number of Nissl bodies, the mRNA expression level of BDNF, and the protein expression levels of BDNF, p-TrkB, and p-CREB in the model group were significantly reduced compared with the control group (P<0.001). After inhibition of the expression of miR-204, the number of Nissl bodies, the mRNA expression level of BDNF, and the protein expression levels of BDNF, p-TrkB, and p-CREB significantly increased, while the cell apoptosis rate and the expression level of miR-204 in the hippocampus significantly decreased. The escape latency was also reduced, while the number of platform crossings increased after inhibition of the expression of miR-204 (P<0.001). CONCLUSIONS: Inhibiting miR-204 can improve the learning and memory functions of neonatal rats with IUGR, possibly by targeted activation of the BDNF/TrkB signaling pathway.

Biotic and abiotic factors that affect parasitism in Trichogramma pintoi (Hymenoptera: Trichogrammatidae) as a biocontrol agent against Heortia vitessoides (Lepidoptera: Pyralidae).

The parasitoid wasp, Trichogramma pintoi, is a promising candidate for inundative release against Heortia vitessoides. Parasitoid females can regulate the sex of their offspring in response to environmental and biological factors. In pest control programs utilizing these parasitoids, male overproduction is not conducive to success. To optimize the production of T. pintoi as an egg parasitoid of H. vitessoides, factors affecting the rates of parasitism and eclosion and the percentage of females among T. pintoi offspring, such as temperature, photoperiod, host age, host density, maternal age, maternal density, and food, were investigated. The proportion of T. pintoi female offspring was significantly affected by temperature, photoperiod, host density, maternal age, and maternal density. The female offspring percentage decreased in response to host density (160 eggs), maternal age (≥ 4 days old), maternal density (≥ 4 females), photoperiods (24:0 and 18:6 L:D), and extremely low temperature (15 °C). However, host age and female diet did not affect the proportion of female offspring. According to the present work, female parasitoid production can be maximized under laboratory conditions of 25 °C, 75% relative humidity, and a photoperiod of 0:24 h (L:D) via exposure of forty 1-day-old H. vitessoides eggs for 24 h or eighty 1-day-old H. vitessoides eggs to a newly emerged, mated female fed a 10% sucrose solution until the female dies. These findings will guide mass production efforts for this parasitoid.

Potential Use of Trichogramma pintoi as a Biocontrol Agent Against Heortia vitessoides (Lepidoptera: Pyralidae).

Heortia vitessoides Moore is the most serious insect defoliator of Aquilaria sinensis (Lour.) Gilg, an endangered and economically important plant that produces highly prized agarwood. Samples from recently identified indigenous natural populations of Trichogramma pintoi Voegele were collected from H. vitessoides eggs in A. sinensis forests in Yunnan Province, China. To assess the potential capacity of this parasitoid for use as a biological control agent, its functional response, female reproductive potential, and male insemination capacity were investigated in this study. Females successfully parasitized 1- to 4-d-old eggs of H. vitessoides but failed to parasitize 5- to 8-d-old eggs. The parasitoid exhibited a Holling type II functional response, and the estimated maximum numbers of 1- to 4-d-old H. vitessoides eggs parasitized by a single T. pintoi female were 38.1, 29.8, 26.0, and 22.2 eggs over a 24-h period, respectively. Additionally, the parasitoid's average lifetime fecundity was 89.8 ± 2.5 eggs, of which 66.26% were laid within the first 2 d. The average number of total females that mated with a male in his lifetime (4.70 ± 0.13 d) was 10.4, and the average number of total daughters of a male was 292.1. On day 1 of male adult life, the greatest number of females were inseminated by males, and the most daughters were produced; however, the number of copulations and insemination ability decreased rapidly with male age. These results suggest that T. pintoi is a promising candidate for inundative release against H. vitessoides in China, and these findings will guide efforts in achieving mass production of this parasitoid.