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OBJECTIVE: To investigate the influences of long non-coding ribonucleic acid (lncRNA) H19 on proliferation and apoptosis of nephroblastoma cells. MATERIALS AND METHODS: A total of 5 pairs of nephroblastoma tissues and paraneoplastic tissues were obtained. Gene expression levels of lncRNA H19, microRNA (miR)-675, and transforming growth factor beta induced (TGFBI) were detected via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). Their regulatory effects on the viability of nephroblastoma cells were examined by Cell Counting Kit-8 (CCK-8) assay. Finally, the apoptosis level in each group was detected through TUNEL assay, and the protein expressions of TGFBI and Caspase-8 were examined using Western blotting (WB) assay. RESULTS: The gene expression levels of lncRNA H19 and miR-675 were markedly downregulated in nephroblastoma tissues (p<0.05), while that of TGFBI was notably upregulated (p<0.05). LncRNA H19 could reduce the proliferative ability of HFWT cells (p<0.05) and stimulates apoptosis rate (p<0.05). It upregulated the expressions of miR-675 and Caspase-8 (p<0.05), and downregulated TGFBI (p<0.05). Besides, miR-675 was able to upregulate Caspase-8 (p<0.05) and downregulate TGFBI (p<0.05). In addition, the protein expression of Caspase-8 was downregulated (p<0.05), while that of TGFBI was upregulated (p<0.05) after the knockdown of miR-675 in HFWT cells. CONCLUSIONS: LncRNA H19 may inhibit TGFBI expression by regulating miR-675 level, so as to weaken the proliferation and enhance the apoptosis of nephroblastoma cells. [ABSTRACT FROM AUTHOR]

Aims: Constructing a strain with high yield of O‐succinyl‐l‐homoserine (OSH) and improving the titre through multilevel fermentation optimization. Methods and results: OSH high‐yielding strain was first constructed by deleting the thrB gene to block the threonine biosynthesis. Single‐factor experiment was carried out, where a Plackett–Burman design was used to screen out three factors (glucose, yeast and threonine) from the original 11 factors that affected the titre of OSH. The Box–Behnken response surface method was used to optimize the fermentation conditions. Through gene editing and medium optimization, the titre of OSH increased from 7·20 to 8·70 g l−1 in 500 ml flask. Furthermore, the fermentation process and fed‐batch fermentation conditions including pH, temperature, feeding strategy and feeding medium were investigated and optimized. Under the optimal conditions, the titre of OSH reached 102·5 g l−1, which is 5·6 times higher than before (15·6 g l−1). Conclusions: O‐succinyl‐l‐homoserine fermentation process was established and the combination of response surface methodology and metabolic pathway analysis effectively improved the titre of OSH. Significance and Impact of the Study: In this study, the titre of OSH reached the needs for industrial production and the metabolic pathway of OSH was demonstrated for further optimization. [ABSTRACT FROM AUTHOR]

Antibiotics are designed to affect gut microbiota and subsequently gut homeostasis. However, limited information exists about short- and long-term effects of early antibiotic intervention (EAI) on gut homeostasis (especially for the small intestine) of pigs following antibiotic withdrawal. We investigated the impact of EAI on specific bacterial communities, microbial metabolites and mucosal immune parameters in the small intestine of later-growth-stage pigs fed with diets differing in CP levels. Eighteen litters of piglets were fed creep feed with or without antibiotics from day 7 to day 42. At day 42, pigs within each group were offered a normal- or low-CP diet. Five pigs per group were slaughtered at days 77 and 120. At day 77, EAI increased Enterobacteriaceae counts in the jejunum and ileum and decreased Bifidobacterium counts in the jejunum and ileum (P < 0.05). Moreover, tryptamine, putrescine, secretory immunoglobulin (Ig) A and IgG concentrations in the ileum and interleukin-10 (IL-10) mRNA and protein levels in the jejunum and ileum were decreased in pigs with EAI (P < 0.05). At day 120, EAI only suppressed Clostridium cluster XIVa counts in the jejunum and ileum (P < 0.05). These results suggest that EAI has a short-term effect on specific bacterial communities, amino acid decarboxylation and mucosal immune parameters in the small intestine (particularly in the ileum). At days 77 and 120, feeding a low-CP diet affected Bifidobacterium, Clostridium cluster IV, Clostridium cluster XIVa and Enterobacteriaceae counts in the jejunum or ileum (P < 0.05). Moreover, feeding a low-CP diet increased the concentrations of Igs in the jejunum and decreased pro-inflammatory cytokines levels in the jejunum and ileum (P < 0.05). At day 120, feeding a low-CP diet increased short-chain fatty acid concentrations, reduced ammonia and spermidine concentrations and up-regulated genes related to barrier function in the jejunum and ileum (P < 0.05). These results suggest that feeding a low-CP diet changes specific bacterial communities and intestinal metabolite concentrations and modifies mucosal immune parameters. These findings contribute to our understanding on the duration of the impact of EAI on gut homeostasis and may provide basis data for nutritional modification in young pigs after antibiotic treatment. [ABSTRACT FROM AUTHOR]

Gut microbes, especially those in the large intestine, are actively involved in nutrient metabolism; however, their impact on host nitrogen (N) metabolism remains largely unknown. This study was designed to investigate the effects of feeding a cocktail of antibiotics (AGM) (ampicillin, gentamycin and metronidazole) on intestinal microbiota, N utilization efficiency, and amino acid (AA) digestibility in cannulated pigs, with the aim of exploring the impact of gut microbiota on host N metabolism. In total, 16 piglets were surgically fitted with a simple distal ileal T-cannula and a jugular venous catheter. The pigs were fed a basal diet without antibiotics (control; CON) or with antibiotics (antibiotic; ANTI), for 2 weeks. The results showed that feeding AGM did not affect weight gain or digestive enzyme activity. The antibiotics increased the concentration of urea N (P <0.05). However, they reduced N utilization, and the total tract apparent digestibility of isoleucine, methionine, valine, tyrosine and total AA (P <0.05). Furthermore, the antibiotics increased the terminal ileum apparent digestibility of CP, phenylalanine, valine, alanine, tyrosine and total AA (P <0.05). AGM markedly altered the composition of the microbiota in the ileum and feces, with a reduction in populations of Bifidobacterium , Lactobacillus and Ruminococcus , and an increase in the abundance of Escherichia coli (P <0.05). The antibiotics also significantly increased the concentration of cadaverine and ammonia, both in ileal digesta and feces (P <0.05), suggesting a marked impact on N metabolism in the intestine. The analyses indicated that the alteration of gut microbiota was correlated with the apparent digestibility of CP and AA in the intestine. These findings suggest that the AGM-induced alteration of gut microbiota may contribute to the change in intestinal N metabolism, and consequently, N excretion from the body. These results also suggest that antibiotics could have a significant effect on host N metabolism. The present study contributes to our understanding of the effects of antibiotics and provides a rational scientific basis for diet formulation during AGM use. [ABSTRACT FROM AUTHOR]

Dry gas overlies on condensate gases and flows due to the difference in density. This phenomenon affects cyclic injection exploitation and increases production costs. A mathematical model of dry gas migration was developed in this study to investigate the migration characteristics and the overlying law for dry gas in the condensate gas reservoir. On the basis of the theory of convection diffusion, the governing equations were constructed, using dry and condensate gases as two pseudocomponents. The distribution and transition belt of dry gas, as well as the effects of condensate oil and the perforation method on overlying of dry gas were discussed based on the dry gas migration model. The results demonstrate that the width of the transition belt of dry and condensate gases increases gradually over time. The mole fraction of gas in the transition belt is dense in the middle, but sparse at the two ends. The overlying of dry gas is easy, taking condensate oil into consideration. The value of F increases by 0.32, but the width of the transition belt becomes narrow. The transition belt under the top perforation of the reservoir is wider than that under symmetric perforation, and the overlying degree of dry gas increases. This study provides a theoretical foundation for in situ adjustment and optimization of cyclic gas injection utilization. [ABSTRACT FROM AUTHOR]

To enhance the surface accuracy of laser metal direct forming pieces, a method applying femtosecond laser to fabricate the cladding sidewalls is proposed in this paper. The effects of laser fluence, scanning speed and scanning strategy on the processing accuracy are studied systematically. The experimental results show that when the laser fluence increases, the roughness of cladding sidewalls also increases. The roughness of the cladding sidewall is decreased firstly and then increased with the increasing scanning speed. When the laser fluence is between 0.12 and 0.34 J/ cm2, the roughness of cladding sidewall is less than 3 µm. What is more, under single scanning strategy the sidewalls roughness is less than that when back and forth scanning method is used. [ABSTRACT FROM AUTHOR]