In the process of aquaculture, too high protein level of feed will lead to high nitrogen content in fish excreta, eutrophication of water body, and serious water pollution. However, the metabolic mechanism of endogenous ammonia and its nutritional regulation measures have not been reported. Therefore, this paper summarized the production mechanism of fish endogenous ammonia, ammoniatolerance strategy, and the corresponding nutritional regulation measures of reducing ammonia emission, which is of great significance to aquatic animal health and will provide a theoretical basis for reducing the concentration of ammonia in the water environment and improving the growth performance of fish.
Viviparity is one of the major disasters threatening food security. To explore the molecular mechanism of regulating maize viviparity, F2 segregating population derived from the hybrid of maize viviparous vplike 4 with inbred lines Zheng58 and Mo17 was used as materials, the differentially expressed genes between wild type and corresponding mutants were compared by transcriptome sequencing (RNA SEQ) and bioinformatics, and the functions of the differentially expressed genes and related metabolic pathways were analyzed. The results showed that there were 3 376 differentially expressed genes (DEGS) in the mutant, of which 2 252 were upregulated and 1 124 were down regulated. GO (Gene ontology) functional enrichment analysis indicated that 2 151 DEGs were annotated and enriched in 716 GO taxonomic entries, which were mainly correlated to metabolism and stress response. Referring to KEGG database, the metabolic pathways of differential genes were analyzed. It was found that differential genes were significantly enriched in plant hormone signal transduction, starch and sucrose metabolism, photosynthesis and other pathways. The above results show that DEGs, GO taxonomic entries and metabolic pathways were closely related to viviparity of maize. These results will provide important data supports for investigating viviparous genes and related regulatory network comprehensively.
In this experiment, the SAMDC gene in maize was obtained by homologous alignment in rice, and the protein structure and physical and chemical properties of the gene were analyzed by bioinformatics software. The results showed that ZmSAMDC is a hydrophobic nontransmembrane protein with no signal peptide structure. The molecular weight of ZmSAMDC protein is 43 28312 D, the isoelectric point is 478, and the number of amino acids is 398. The halflife in E. coli is predicted to be greater than 10 hours, and the protein instability coefficient is 3832. The protein is a stable protein. ZmSAMDC protein has 44 potential phosphorylation sites, including 23 serine (Ser) phosphorylation sites, 12 threonine (Thr) phosphorylation sites, 9 proline (Tyr) phosphorylation sites, and phosphoric acid mainly concentrated on threonine, serine and proline residues. The secondary structure of ZmSAMDC protein consists of α-helix, extended chain, random coil and β-turn. The ZmSAMDC domain is the SAM_decarbox domain, and the subcellular cells are mainly localized on the extracellular matrix. This study provides new information for the study of the structure and function of the new maize gene, SAMDC, and lays a foundation for the study of ZmSAMDC gene.
In order to optimize the genetic transformation receptor system of soybean, the affecting factors of seed germination and adventitious bud induction were investigated by orthogonal test design on soybean varieties JN18, JN28 and JN54. The results showed that the optimal condition for soybean seed germination is to select JN28 soybean sterilized by sodium hypochlorite solution for 10 min, and inoculated on MS+0.2 mg/L 6-BA germination medium (pH 6). The optimal condition for adventitious bud induction of soybean cotyledon node is to inoculate the seeds germinated for 5 d on MS+3.0 mg/L 6-BA + 0.2 mg/L IBA medium. According to the obtained optimal conditions, the Agrobacteriummediated transformation for JN28 was applied, and the positive transformation rate of PCR was 5.56%. This result lays foundation for the identification of soybean gene function and the acquisition of new genetically modified soybean lines with independent intellectual property rights.
This study isolated and purified two strains JL-006 and JL-007 firstly from naturally entomopathogeninfected Myzus persicae and Trialeurodes vaporariorum, which were identified to be Lecanicillium longisporum and Lecanicillium lecanii by morphology and rDNA-ITS sequence analysis. To assess the biological control potential, the pathogenicity of JL-006 and JL-007 with another two fungal strains Lecanicillium attenuatum JL-003 and Beauveria bassiana JL-005 to 3rdinstar nymphs of M. persicae and T. vaporariorum were determined using the dipping method. The results indicated that the virulence was higher at the concentration of 1.0×108 conidia/mL than at 1.0×1.5 conidia/mL. The strains B. bassiana JL-005 and L. longisporum JL-006 were promising candidates for biological control of M. persicae with the higher mortalities of 71.8% and 74.5%, and the lower LT50 values of 5.6 d and 5.5 d, respectively, after inoculation for 10 days. Meanwhile, the strains B. bassiana JL-005 and L. lecanii JL-007 were promising candidates for biological control of T. vaporariorum with the higher mortalities of 82.3% and 80.5%, and lower LT50 values of 5.4 d and 5.1 d, respectively. Our results provide a technical support for simultaneously suppressing several insect pests by a pathogenic fungus in greenhouse.
Pluronic is a classical thermosensitive polymer that achieves solgel transition with the change of temperature.However, the structure of hydrogel is unstable, and it is difficult to preserve long, and has a single function in wound dressing application. In this research, the thermosensitive composite hydrogel was synthesized by mixing pluronic F127 and F68 with an antibacterial component CS which can also be used for irregular wound healing. The temperature sensitivity, microscopic morphology, antibacterial activity and the fit to the wound were investigated by test tube inversion, SEM, bacterial coating method and wound model. The results showed that the composite hydrogel was thermosensitive, and formed gelatin at body temperature. The F127/F68/CS hydrogel showed a structure feature of high porosity and 3dimensional networks. The antibacterial was gradually increased with the increase of CS. And the hydrogel could adhere tightly on the wound. F127/F68/CS composite hydrogel is expected to reduce wound infection and promote wound healing due to its convenience of preparation, temperature sensitivity, suitable porous structure, antibacterial properties and good wound adhesion.
In order to study the relationship between the structural changes and gel properties of transglutaminase crosslinked soybean protein isolate (SPI), the correlation between SPI structural changes and gel strength after crosslinking was studied by SPSS software Person analysis. The results showed that SPI structural characteristics changed after cross linking of SPI with transglutaminase, hydrophobic groups were exposed and surface hydrophobicity was increased by 35.9%. The content of surface sulfydryl was decreased by 24.8%, the content of disulfide bond was increased by 10.3%, and the content of free amino was reduced by 73.8%. The results of correlation study showed that surface hydrophobicity levels were positively correlated with gel strength, and sulfhydryl content was negatively correlated with gel strength. Disulfide bond was significantly positively related to gel strength and the content of free amino and gel strength had significant negative correlation. The four structural characteristics all affect gel strength, and hydrophobicity and disulfide bond on the surface are beneficial to improving gel strength.
In order to clarify the soil nutrients and comprehensive fertility of Panax ginseng cultivated in farmland and provide reference for rational planting ginseng, 14 soil nutrient indexes of 42 soil samples from 14 counties and cities in ginseng producing areas were studied, the soil fertility status was comprehensively evaluated by principal component analysis and fuzzy mathematics membership function model, and the comprehensive index value (IFI) of soil fertility was calculated. The results showed that the contents of soil organic matter, total nitrogen, total phosphorus, alkalihydrolyzed nitrogen, available potassium, available iron and manganese were sufficient. The average of IFI value of soil fertility index of farmland ginseng in field producing area was 0.71, and most of them were in gradeⅠand grade Ⅱ. Among them, the soil fertility accounted for 66.67% of the sampling area, and the overall level of soil was good.
Psychrotolerant bacteria, which can induce carbonate precipitation of heavy metals at low temperature, have important application potential in the remediation of heavy metal contaminated soil in cold area. However, there is a lack of research on remediation and stability of various heavy metal contaminated soil. In this study, the immobilization of four heavy metals by a psychrotolerant carbonate mineralizing bacteria (Corynebacterium glutamicum DC1) and its stability in soil were studied. The results showed that the bacterial culture of strain DC1 could transform exchangeable Cd, Pb, Cu and Ni into carbonate bound through inducing carbonate precipitation with the conversion ratio of 79.8%, 72.6%, 39.9% and 33.6%, respectively in soil, resulting in the reduction of te available Cd,Pb,Cu and Ni by 90.5%, 83.4%, 35.1% and 36.6%，respectively, together with the increase of soil pH. Soil acidification decreased the stability of Cu and Ni by strain DC1, but there was no significant effect on Pb and Cd. Under the conditions of simulated dry and paddy soil and fertilizer application, there was no significant release of Pb and Cd in carbonate precipitates induced by strain DC1 in the soil, and the soil available Pb and Cd were not significantly increased after 30 days of incubation. The above results indicate that strain DC1 could be used for remediation of heavy metal contaminated soil through inducing carbonate precipitate, especially for Pb and Cd contaminated soil. However, for Cu and Ni, more attention should be paid to soil acidification.
Fermented corn stalk (FCS) was used to replace the basic diets and the effects of dietary nutrient levels on the growth performance, nutrient digestibility, slaughter performance, meat quality, and economic benefits of different growth stages of Songliao black swine were studied to determine the appropriate level of substitution for fermented corn stalk. A total of 96 healthy Songliao black pigs with an average body weight of (60.52±4.59) kg were randomly divided into 4 groups with 3 replicates in each group and 8 pigs per replicate. The test was divided into two fattening stages: fattening stage 1 (60-90 kg) and fattening stage 2 (90-120 kg). Group 1 represents the control group and pigs in this group were fed the basal diet. Group 2, Group 3 and Group 4 were the trial groups and pigs in these groups were fed with 6%, 12% and 18% fermented corn stalk, respectively. The experimental period lasted for 80 days (40 days +40 days). At the end of the experiment, the growth performance, slaughter performance, nutrient digestibility, and meat quality of Songliao black swine were tested. The results showed as follows: The final body weight and average daily weight gain of group 2 were significantly higher than those of group 4 (P<0.05). In addition, the feed conversation ratio of group 1 and group 2 was significantly lower (P<0.05) than group 3 and group 4. The digestibility of crude protein and crude fat in group 2 increased by 2.27% and 1.33% compared with group 1. The digestibility of crude fiber in group 1 and group 2 was significantly higher (P<0.05) than that in group 3 and group 4. The digestibility of neutral detergent fiber in group 1 was significantly higher than group 4 (P<0.05). The difference in the slaughter rate was not significant (P>0.05) in each group and the back fat thickness decreased with the increase of FCS addition. The loss of drip in 24 hours was lower in group 2, which was significantly lower than that in group 3 (P<0.05). The rate of cooked meat in group 1 was not significantly different from that in group 2. Calculation and analysis of economic benefits show that the feed cost of all the groups increased with the increase of FCS addition, but the economic benefits of group 2 was the highest. The economic benefits of each pig in group 2 was higher than group 1 by 14.17 yuan. In summary: the use of 6% FCS to replace the basic diet may adjust the nutritional levels of the diet, and hence improve the growth performance, economic benefits, feed nutrient digestibility, and meat quality of Songliao black swine.
The purpose of this study is to analyze and investigate stress resistance and growth characteristics of Lactobacillus amylovorus L-102 and Lactobacillus johnsonii L-76 from swine, and to provide a theoretical basis for further in vitro studies of lactic acid bacteria. Acidbase tolerance, bile tolerance, trypsin tolerance, adhesiveness, bacteriostatic ability, acid production ability, growth curve and pathogenicity of Lactobacillus L-102 and L-76 were measured and analyzed. The results showed that Lactobacillus L-102 and L-76 exhibited resistance to acidbase environment with pH values of 2-11, and could tolerate 0.1%-0.2% bile salts and 1% trypsin in growth medium. The two Lactobacillus strains had certain adhesion to IPEC-J2 cell and inhibited the growth of Escherichia coli, Salmonella Typhimurium and Staphylococcus aureus. Moreover, the range of acid production of Lactobacillus L-102 and L-76 is 4.10-4.30. After 4 hours of culture, it entered the logarithmic phase of growth. The viable count achieved 107 CFU/mL when Lactobacillus L-102 and L-76 were sustained at 50 ℃ and 60 ℃ for 5-15 min. No death mice were found in mice injected intraperitoneally and administered intragastrically with Lactobacillus L-102 and L-76. Data indicated that Lactobacillus amylovorus L-102 and Lactobacillus johnsonii L-76 have potential probiotic characteristics and could develop into feeding probiotic lactic acid bacteria for swine industry.
In order to develop a detection method for diagnosing Brucella in velvet antler and deer blood rapidly, and to ensure the safety of related deer products used for food and medicine, primers and probes were designed and synthesized on the base of the specific gene IS711 of Brucella. A realtime fluorescence quantitative PCR method was established. The reaction conditions were optimized and a standard kinetic curve, Y=-3.14X+37.62，R2=0.997,was drawn. The method has good reproducibility, sensitivity and specificity. The standard deviation of Ct value for intragroup and intergroup reproducibility tests is less than 0.5, the variation coefficients are all less than 2%, and the minimum detectable copy number is 2.65×101Copies/μL, with good specificity for Brucella abortus IS711 gene. The results showed that the method is sensitive to target gene detection and can be used for the detection of fresh velvet antler, deer blood and other related samples. The method can also be used for the qualitative and quantitative detection of Brucella, providing an important technical guarantee for the quality and safety assessment of related deer products.
Copyright 2009 Journal of Jilin Agricultural Univerisity
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