[Effects of N, P, and K application rates on distribution of 13C assimilates, starch accumulation in grains and fertilizer utilization of wheat]. / 氮磷钾施用量对小麦旗叶13CåŒåŒ–ç‰©åˆ†é ã€ç±½ç²’æ·€ç²‰ç§¯ç´¯å’Œè‚¥æ–™åˆ©ç”¨çš„å½±å“.

Clarifying the appropriate application rates of N, P, and K fertilizers and the physiological mechanisms of wheat under water-saving recharge irrigation in the North China Plain would provide a theoretical basis for formulating reasonable fertilization plans for high-yield and high-efficiency wheat production. We established four treatments with different amounts of nitrogen (N), phosphorus (P2O5), and potassium (K2O) application: 0, 0, and 0 kg·hm-2 (F0), 180, 75, and 60 kg·hm-2 (F1), 225, 120, and 105 kg·hm-2 (F2), and 270, 165, and 150 kg·hm-2 (F3). During the jointing and anthesis stages of wheat, the relative water content of each treatment in the 0-40 cm soil layer was replenished to 70%, to investigate the differences in wheat flag leaf photosynthetic characteristics, distribution of 13C assimilates, grain starch accumulation, and fertilizer utilization. The results showed that the relative chlorophyll content of flag leaves, photosynthetic and chlorophyll fluorescence parameters, 13C assimilate allocation in each organ, enzyme activities involved in starch synthesis, and starch accumulation in the F1 treatment were significantly higher than that in F0 treatment, which was an important physiological basis for the 20.9% increase in grain yield. The above parameters and yield in the F2 and F3 treatments showed no significant increase compared to F1 treatment, while fertilizer productivity and agronomic efficiency of N, P, and K decreased by 17.5%-58.4% and 12.7%-50.7%, respectively. Therefore, F1 could promote flag leaf photosynthetic assimilate production and grain starch accumulation under water-saving supplementary irrigation conditions, resulting in higher grain yield and fertilizer utilization efficiency.

MCT1-mediated transport of valeric acid promotes porcine preimplantation embryo development by improving mitochondrial function and inhibiting the autophagic AMPK-ULK1 pathway.

Oocytes and embryos are highly sensitive to environmental stress in vivo and in vitro. During in vitro culture, many stressful conditions can affect embryo quality and viability, leading to adverse clinical outcomes such as abortion and congenital abnormalities. In this study, we found that valeric acid (VA) increased the mitochondrial membrane potential and ATP content, decreased the level of reactive oxygen species that the mitochondria generate, and thus improved mitochondrial function during early embryonic development in pigs. VA decreased expression of the autophagy-related factors LC3B and BECLIN1. Interestingly, VA inhibited expression of autophagy-associated phosphorylation-adenosine monophosphate-activated protein kinase (p-AMPK), phosphorylation-UNC-51-like autophagy-activated kinase 1 (p-ULK1, Ser555), and ATG13, which reduced apoptosis. Short-chain fatty acids (SCFAs) can signal through G-protein-coupled receptors on the cell membrane or enter the cell directly through transporters. We further show that the monocarboxylate transporter 1 (MCT1) was necessary for the effects of VA on embryo quality, which provides a new molecular perspective of the pathway by which SCFAs affect embryos. Importantly, VA significantly inhibited the AMPK-ULK1 autophagic signaling pathway through MCT1, decreased apoptosis, increased expression of embryonic pluripotency genes, and improved embryo quality.

[Coexpression of human complement regulatory protein genes, CD59 and MCP in transgenic mice protects isolated mouse heart function in ex vivo human plasma perfusion model].

OBJECTIVE: To investigate if the expression of human complement regulatory protein genes in transgenic donor protects against hyperacute rejection (HAR) in the recipient. METHODS: Kunming mice were transfected with 2 human complement regulatory protein genes, CD59 and MCP, so as to establish a transgenic hCD59/hMCP mouse model. Eight hCD59 expression mice, 11 hMCP expression mice, and 8 hCD59/hMCP expression mice were used as experimental groups, and 10 transgenic negative littermates were used as control group. The hearts of the mice were taken out to be perfused with 10% pooled human blood of B type. During the perfusion electrocardiography was carried out to observe the beating time. After the hearts stopped beating, immunofluorescence staining and immunohistochemistry were used to detect the deposition of complements C(9) and C(3c) in the heart tissue. RESULTS: The mean heart beating time was 138 +/- 25 minutes in the hCD59/hMCP expression group, 78 +/- 27 minutes in the hCD59 expression group, 43 +/- 21 minutes in the hMCP group, and 20 +/- 12 minutes in the wild type nontransgenic control group (all P < 0.01, Dennett's T test for all 3 other groups relative to the hCD59/hMCP group). Deposition of the complement C(9) and that of C(3c) were not found in the hearts of the hCD59/hMCP group, however, could be found in the hearts of the 2 monotransgenic groups and nontransgenic group. CONCLUSION: The coexpression of human complement regulatory protein genes, CD59 and MCP in the xenografts effectively inhibits the complement of xenograft-mediated HAR.

[Establishment of a new method for early embryo culture in vitro].

A new method, nest culture method, was developed in this study. The culture effects of different methods for embryo culture in vitro were compared. The results showed that whether the suspension in phi35mm dish in nest culture method was covered with mineral oil or not, the developmental rates of embryos had no significant difference. Compared to the nest culture method, the developmental rates of embryos in Brinster's method were significant lower. However, all embryos cultured in the single dish in which the suspensions were not covered with mineral oil were blocked at 2-cell stage. The nest culture method is an effective method for early embryo culture in vitro.