General anesthetic agents induce neurotoxicity through astrocytes

Neuroscientists have recognized the importance of astrocytes in regulating neurological function and their influence on the release of glial transmitters.Few studies,however,have focused on the effects of general anesthetic agents on neuroglia or astrocytes.Astrocytes can also be an important target of general anesthetic agents as they exert not only sedative,analgesic,and amnesic effects but also mediate general anesthetic-induced neurotoxicity and postoperative cognitive dysfunction.Here,we analyzed recent advances in understanding the mechanism of general anesthetic agents on astrocytes,and found that exposure to general anesthetic agents will destroy the morphology and proliferation of astrocytes,in addition to acting on the receptors on their surface,which not only affect Ca^(2+)signaling,inhibit the release of brain-derived neurotrophic factor and lactate from astrocytes,but are even involved in the regulation of the pro-and anti-inflammatory processes of astrocytes.These would obviously affect the communication between astrocytes as well as between astrocytes and neighboring neurons,other neuroglia,and vascular cells.In this review,we summarize how general anesthetic agents act on neurons via astrocytes,and explore potential mechanisms of action of general anesthetic agents on the nervous system.We hope that this review will provide a new direction for mitigating the neurotoxicity of general anesthetic agents.

Xuefuzhuyu decoction and astragalus prevent hypoxic-ischemic brain injury

Hypoxic-ischemic brain injury models were generated by bilateral carotid artery ligation in Sprague-Dawley rats. Successful models were treated with a combination of Xuefuzhuyu decoction and 10g of astragalus. The experimental results showed that neuronal morphology and structure recovered, nerve growth factor mRNA expression increased in brain tissues, and neurological function signifi-cantly improved. There was no significant difference in these measures compared with rats treated with Xuefuzhuyu decoction alone or a combined treatment of Xuefuzhuyu decoction with 40 g as-tragalus. These experimental findings revealed that, Xuefuzhuyu decoction combined with astra-galus may up-regulate the expression of nerve growth factor mRNA and accordingly exert a neu-roprotective effect; however, this protection is not dependent on astragalus dosage.

Effects of Supplemental Feeding of Probiotics during Lactation on Rumen Microflora of Calves after Weaning

For the experiment, 8 newborn male Holstein calves were selected that had the same feeding environment, and were of similar ages. They were randomly divided into 2 groups, with 4 in each group. The treatments consisted of feeding active probiotics (Group P) and a normal fed control group (Group C). The growth performance and blood indices were measured;rumen fluid samples were collected after weaning, and 16SrDNA sequencing and LC-MS metabolome detection were performed. Compared with the control group, relative abundances of Deltaproteobacteria, Desulfovibrionales, Bacteroidales_ BS11_gut_group, Desulfovibrionaceae, Bacteroidales_S24-7_group, Acetobacteraceae, Ruminococcaceae_NK4A214_group, Asaia, [Ruminococcus] gauvreauii_group, Desulfovibrio, Kingella, Selenomonas, Lachnoclostridium in group P were significantly different (P < 0.05). In group P, the metabolite of 2-methylbenzoic acid and myo-inositol were significantly increased (P < 0.05). These results showed that compared with normally fed calves, the growth performance and blood indices of probiotic-fed calves were changed, but the differences were not significant. Probiotic-fed calves showed significant differences in rumen fluid and a small number of metabolites, which were mainly involved in the pathway of carbohydrate metabolism. It proves that the supplemental active probiotics had an effect on the rumen microflora.

A Study on the Mechanism Regulating Acetate to Propionate Ratio in Rumen Fermentation by Dietary Carbohydrate Type

The research direction of our team is nutrition and physiology of ruminants, including dietary nutrition metabolism and rumen microorganisms. Previous research has shown that ruminal acetate-to-propionate ratio is related to diet utilization efficiency. At present, it is believed that the main factors affecting the ruminal acetate-to-propionate ratio are the degradation rate of the diet and the rumen microbial structure, but the main mechanism is unclear. This study found that the effect of ruminal acetate-to-propionate ratio was not affected by the concentration of the fermentation substrate, but was affected by the structure of the rumen microbiota. We believe that changes in the rumen microflora structure are the main mechanism for regulating the ruminal acetate-to-propionate ratio. This will help people to further understand the rumen physiology, thereby gradually improving feed conversion efficiency and reducing production costs. Abstract: In order to explore the mechanism by which diet regulates the acetate-to-propionate molar ratio (A: P ratio), we compared the effect on rumen fermentation parameters and the microbiome by altering the ratio of dietary concentrates to roughage ratio and calcium pyruvate infusion. The test animals were Laoshan dairy goats, and were fed continuously through an automatic feeder. The test groups were fed a base diet of low concentrates, and intraruminally infused with calcium pyruvate at two concentrations. The infusion concentrations were derived from the difference in the rate of carbohydrate degradation of the high and low concentrate diets, and they were artificially set such that the high concentration infusion group was infused with twice the concentration as the low concentration infusion group. The control groups were fed high concentrate (6:4) and low concentrate (3:7) diets, respectively. The following results were obtained by measuring rumen fermentation parameters and microbial composition: the rumen A: P ratio was significantly lower in the high-concentrate diet group than in the low concentrate diet group (P < 0.05). Infusion of low concentration calcium pyruvate had no significant effect on rumen A: P ratio (P > 0.05), while infusion of high concentration calcium pyruvate significantly increased the rumen A: P ratio (P < 0.05). Relative to goats fed the low concentrate diet, those fed the high concentrate diet had a greater abundance of microbes related to propionate production and a reduced abundance of microbes related to fiber degradation. Infusion of pyruvate had no significant effect on rumen microbial structure. The above results indicate that increasing the concentration of the fermentation substrate without affecting the composition of the microflora does not reduce the A: P ratio. Microbiological results showed that the A: P ratio was more closely related to the rumen microflora structure. Therefore, it is believed that rumen microflora structure is the main mechanism regulating A: P ratio in rumen fermentation.

Effect of High Concentrate Corn Stalk Particle Size on Physical State and Production Performance of Lactating Dairy Cows

In order to realize the application of corn stalk in cow feed, we designed experiments to explore the effect of a certain proportion of corn stalk on the performance of lactating dairy cows. 9 multiparous mid-lactating cows were allocated at random to three groups, each containing 3 intact cows. The trial consisted of three periods and three dietary treatments with a 3 × 3 Latin square design. The diets were normal concentrats plus dried corn stalk chopped to 5 - 8 cm long (N), high concentrates plus dried corn stalks chopped to a length of approximately 5 - 8 cm by a mower (H) while the milled corn stalks were passed through a pulviser with a 2 cm pore size (MH). Each cow was measured for dry matter intake (DMI), ruminal pH, rumen fermentation, selective feeding behavior and production performance. The results showed that MH led to a significantly higher intake of DM, neutral detergent fiber (NDF), forage NDF (FNDF), acid detergent fiber (ADF), crude protein (CP) and organic matter (OM) than N and H (P < 0.05). Cows fed H and MH showed similar selective feeding behavior, while those fed H showed various selectivity for the dietary component. MH resulted in a significantly higher milk production (P < 0.05), and tended to have a higher milk fat production than N (P = 0.055). There were no significant differences in the milk components (P = 0.424) and lactose (P = 0.113) between cows fed N and MH. The high-concentrates plus milled corn stalk diet can increase the milk yield under the premise of normal rumen pH in dairy cows, thereby generating higher economic benefits. And milled corn stalk can effectively inhibit the cow’s selective eating of low-quality roughage.

Effects of Supplementation with <i>Saccharomyces cerevisiae</i>and Its Fermentation Products on Production Performance and Its Mechanism in Perinatal Dairy Cows

The aim of this study was to investigate the effects of Saccharomyces cerevisiae and its fermentation products on performance, blood hormone levels and rumen floral composition in peripartum dairy cows. Sixty perinatal cows were selected and allocated to two groups according to parity and expected date of delivery. Each group was supplemented with Saccharomyces cerevisiae and its fermentation product 0 or 100 g. The results showed that Saccharomyces cerevisiae and its fermentation products could significantly increase the feed intake of peripartum dairy cows (P < 0.01), increase the lactose content after 21 days postpartum (P < 0.01), and tend to increase milk production (P = 0.052). There was no significant effect on other milk components, the apparent digestibility of nutrients. There was a tendency to increase milk production and reduce the number of somatic cells in milk;increase blood levels of glucagon (P < 0.01) and β-hydroxybutyrate (P = 0.01), reducing the insulin content (P = 0.02). Saccharomyces cerevisiae reduced the abundance of rumen microbes in peripartum dairy cows but had no effect on rumen microbial diversity. Compared with the control group, the supplemented group showed reductions in the abundance of genera Bacillus (P = 0.03), Butyrivibrio (P = 0.01), Denitrobacterium (P = 0.01), and Mogibacterium (P < 0.01), Porphyromonas (P = 0.05), Saccharofermentans (P < 0.01), Sphaerochaeta (P = 0.02), Streptococcus (P = 0.04) and other genera. There were significant increase in the content of Acidaminococcus (P = 0.03), Allisonella (P < 0.01), Bulleidia (P < 0.01), Corynebacterium (P = 0.01), Dialister (P < 0.01), Faecalibacterium (P = 0.02), Faekalitalea (P = 0.03), Fibrobacter (P = 0.04), Flavobacterium (P = 0.03), Kandleria (P < 0.01), Paraprevotella (P < 0.01), Pyramidobacter (P = 0.05), Roseburia (P < 0.01), Succinivibrio (P < 0.01) and other genera. The main metabolic pathways such as tryptophan metabolism and steroid hormone biosynthesis in perinatal dairy cows were determined for Saccharomyces cerevisiae and its fermentation products.

Ketamine induces tau hyperphosphorylation at serine 404 in the hippocampus of neonatal rats

Male Wistar 7-day-old rats were injected with 40 mg/kg ketamine intraperitoneally, followed by three additional injections of 20 mg/kg ketamine each upon restoration of the righting reflex. Neonatal rats injected with equivalent volumes of saline served as controls. Hippocampal samples were collected at 1,7 or 14 days following administration. Electron microscopy showed that neuronal structure changed noticeably following ketamine treatment. Specifically, microtubular structure became irregular and disorganized. Quantitative real time-PCR revealed that phosphorylated tau mRNA was upregulated after ketamine. Western blot analysis demonstrated that phosphorylated tau levels at serine 396 initially decreased at 1 day after ketamine injection, and then gradually returned to control values. At 14 days after injection, levels of phosphorylated tau were higher in the ketamine group than in the control group. Tau protein phosphorylated at serine 404 significantly increased after ketamine injection and then gradually decreased with time. However, the levels of tau protein at serine 404 were significantly greater in the ketamine group than in the control group until 14 days. The present results indicate that ketamine induces an increase of phosphorylated tau mRNA and excessive phosphorylation of tau protein at serine 404, causing disruption of microtubules in the neonatal rat hippocampus and potentially resulting in damage to hippocampal neurons.

含噻二唑季铵盐表面活性剂对Q235钢的缓蚀性能

通过表面张力法研究一种含噻二唑季铵盐表面活性剂(MTOTB)在1 mol/L HCl溶液中的表面活性;通过电化学测试、静态失重和表面形貌分析研究MTOTB及相应的2-巯基-5-甲基-1,3,4-噻二唑(MMTD)在1 mol/L HCl溶液中对Q235碳钢的缓蚀性能。结果表明,MTOTB在1 mol/L HCl溶液中的临界胶束浓度为0.36 mmol/L;当添加浓度为0.5 mmol/L时,MTOTB对在1 mol/L HCl溶液中浸泡48 h碳钢片的缓蚀率可达95.34%,同样条件下,MMTD对碳钢的缓蚀率为78.34%,说明MTOTB对碳钢的腐蚀抑制效率显著优于MMTD。SEM-EDS表明,MTOTB可以吸附在碳钢表面,有效抑制碳钢片的腐蚀。

Contribution of root respiration to total soil respiration during non-growing season in mine reclaimed soil with different covering-soil thicknesses

An accurate assessment of root respiration in mine reclaimed soil is important for effectively evaluating mining area ecosystems.This study investigated dynamic changes in root respiration and the contribution of root respiration to total soil respiration(R_(r)/R_(t) ratio)during the non-growing season in mine reclaimed soil,with different covering-soil thicknesses.According to the covering-soil thicknesses,the study area was divided into four sites:10-25 cm(site A),25-45 cm(site B),45-55 cm(site C),and 55-65 cm(site D).From November 2017 to April 2018(except February in 2018),the soil respiration,root respiration,temperature at 5 cm,water content,and root biomass were measured.The results show that soil temperature and root respiration exhibited similar diurnal and monthly variations.The root respiration is strongly influenced by soil temperature during the non-growing season,with an exponential and positive relationship(P<0.001).Root respiration varies with the covering-soil thickness and is greatest with a covering-soil thickness of 25-45 cm.The R_(r)/R_(t) ratio also exhibits monthly variations.During the non-growing season,the mean value of the R_(r)/R_(t) ratio is 51.15%in mine reclaimed soil.The study indicates that root respiration is the primary source of soil respiration and is an important factor for estimating the potential emission of soil CO_(2) from mine reclaimed soil at the regional scale.

Gastrointestinal Tract Development in Unweaned Calves Feeding Different Amounts of Milk and Different Starters

This study was conducted to determine the effect of different starter diets and different amounts of milk on growth performance and gastrointestinal tract development in unweaned calves. 16 calves were assigned to 4 groups, 4 calves in each group. These four groups received the following treatments respectively: 1) high milk (6 L) + low starch (21%), high NDF (28%), high molasses (10%) starter (HMLS group);2) high milk (6L) + high starch (40%), low NDF (14%), low molasses (5%) starter (HMHS group);3) low milk (3 L) + low starch (21%), high NDF (28%), high molasses (10%) starter (LMLS group);4) low milk (3 L) + high starch (40%), low NDF (14%), low molasses (5%) starter (LMHS group). The trial was of 2 × 2 factorial design. All calves had free access to hay and water. Results showed that the low milk allowance increased calf concentrate dry matter intake (DMI) and total DMI, reduced body height at 4 weeks of age, reduced heart girth at 6 weeks of age (P < 0.05). The low milk allowance increased complex stomach full weight, reticulorumen full weight, and the percentages of stomach full weight and reticulorumen full weight over body weight (P < 0.05). The low starch, high fiber, high molasses starters reduced the complex stomach full weight, the proportion of the complex stomach empty weight over body weight, reticulorumen empty weight, abomasum full weight, the proportion of abomasum empty weight over body weight and reticulorumen volume (P < 0.05). The low milk allowance increased calf intestine length, small intestine full weight, the proportion of small intestine full weight over body weight, but reduced the jejunum villus width (P < 0.05), increased ruminal pH (P < 0.05). The low milk allowance reduced papilla length in rumen anterior ventral blind sac, but increased papilla length in the posterior ventral sac

Treatment of Agate Dyeing Wastewater Using an Immobilized Gel Mixture with Nano-Fe_(3)O_(4) Sulfate-Reducing Bacteria

To solve the problems of high Cr^(6+),Cr^(3+),SO_(4)^(2-)and H+concentrations,pollution and processing costs associated with agate dyeing industrial drainage,we prepared an immobilized gel mixture for the treatment of such drainage on the basis of microbial immobilization technology.The immobilized gel mixture was composed of sulfate-reducing bacteria(SRB),corn cob,and nano-Fe_(3)O_(4)(nFe_(3)O_(4)).We used a single-factor experiment to determine the optimal dose of each matrix component.We analyzed the mechanism underlying the treatment of agate dyeing wastewater with an immobilized gel mixture by X-ray diffraction and scanning electron microscopy detection.The results of the single-factor test showed that the best treatment was obtained under the following conditions for each matrix component:SRB mass percentage of 30%,nFe_(3)O_(4) dose of 3%,and corn cob mesh size of 100 and dose of 3%.On this basis,we conducted an L9(34)orthogonal experiment to determine the optimal proportion of each matrix component.The results showed that the best treatment was obtained when the gel mixture met the following conditions:SRB mass percentage of 40%,nFe_(3)O_(4) dose of 4%,and corn cob dose of 1%and mesh size of 100.Accordingly,the SO_(4)^(2-),Cr^(6+)and Cr^(3+)removal rates from the agate dyeing drainage were 70.54%,84.75%,and 73.80%,respectively;the total Fe and chemical oxygen demand releases were 1.086 mg·L^(-1)and 1104 mg·L^(-1),respectively;and the pH was 6.27.The gel mixture had the best treatment effect on agate dyeing wastewater under this composition ratio.

Effects of Dietary Energy Density in the Dry Period on the Production Performance and Metabolism of Dairy Cows

Thirty healthy Holstein dairy cows in the dry period were randomly divided into three groups and fed diets with different net energy for lactation (group A: 1.2 Mcal/kg DM, group B: 1.3 Mcal/kg DM, and group C: 1.4 Mcal/kg DM) for 8 weeks prepartum. Thereafter, dairy cows were fed a diet of the same formulation (1.66 Mcal/kg DM) for 12 weeks postpartum. The effects of different dietary energy densities in the dry period on postpartum performance and metabolic parameters of dairy cows were observed. Milk yield was reduced by 14.5% in the low-energy diet group;however, there were no differences in milk composition between the three groups. Postpartum plasma β-hydroxybutyrate, non-esterified fatty acid, growth hormone, and glucagon levels were significantly decreased whereas leptin and neuropeptide levels were elevated in the low-energy diet group. Moreover, body fat mobilization was attenuated, and the decline in postpartum body condition was reduced in the low-energy diet group, thus effectively reducing the postpartum negative energy balance.

Geographical Analysis of Lung Cancer Mortality Rate and PM2.5 Using Global Annual Average PM2.5 Grids from MODIS and MISR Aerosol Optical Depth

Exposure to particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) may increase risk of lung cancer. The repetitive and broad-area coverage of satellites may allow atmospheric remote sensing to offer a unique opportunity to monitor air quality and help fill air pollution data gaps that hinder efforts to study air pollution and protect public health. This geographical study explores if there is an association between PM2.5 and lung cancer mortality rate in the conterminous USA. Lung cancer (ICD-10 codes C34- C34) death count and population at risk by county were extracted for the period from 2001 to 2010 from the U.S. CDC WONDER online database. The 2001-2010 Global Annual Average PM2.5 Grids from MODIS and MISR Aerosol Optical Depth dataset was used to calculate a 10 year average PM2.5 pollution. Exploratory spatial data analyses, spatial regression (a spatial lag and a spatial error model), and spatially extended Bayesian Monte Carlo Markov Chain simulation found that there is a significant positive association between lung cancer mortality rate and PM2.5. The association would justify the need of further toxicological investigation of the biological mechanism of the adverse effect of the PM2.5 pollution on lung cancer. The Global Annual Average PM2.5 Grids from MODIS and MISR Aerosol Optical Depth dataset provides a continuous surface of concentrations of PM2.5 and is a useful data source for environmental health research.

Effect of Substituting Alfalfa by Wheat Straw Powder on Rumen Digestion, Metabolism and Production Performance in Lactating Dairy Cows

China has abundant straw resources. However, the straw has high levels of crude fiber, low levels of crude protein and fat, poor palatability and low digestibility and a large volume. This study explored the feasibility of using wheat straw powder to replace some of alfalfa and the suitable replacement ratio for lactating dairy cows. In this trial, cows in the mid-lactation stage were fed with rations in which alfalfa hay was replaced isocalorically and isonitrogenously at 0%, 20%, 40% and 60% by wheat straw powder to explore the rumen metabolism and production performance of lactating dairy cows. Using a large randomized block design, 60 cows were selected and divided into 4 groups: the positive control group CG (0% replacement), and groups AL (20% replacement), AM (40% replacement), and AH (60% replacement). The pre-feeding period was 2 weeks and the trial period was 8 weeks. Milk yield, milk protein yield, milk protein percentage, lactose yield, lactose percentage, milk fat yield, and milk fat percentage were not affected by the diets, and the differences among the groups were not significant (P > 0.05). The results show that replacing 20% alfalfa with wheat straw powder is most beneficial to production. When only the feed costs were considered, without considering other costs (such as labor, machinery, etc.) in the economic benefit calculation process, and assume that other costs are the same among the groups, and the economic benefits obtained by the AL group were the largest. The experimental results provide a basis for the further development of straw feed.

Evaluation of Feeding Dairy Cow with Whole Wheat Hay and Alfalfa

The preliminary results of this laboratory (unpublished) indicate that the nutritional value of whole wheat hay (wheat hay, for short) is very high, and the milk stage is the best period of wheat hay harvest. In this study, we investigated the feeding effect and economic benefits using wheat hay instead of alfalfa diet for dairy cows under the condition of the same energy and crude protein levels. Three types of diets were used: alfalfa diet, wheat hay diet and alfalfa + wheat hay diet. The results showed that the dry matter digestibility of alfalfa diet and alfalfa + wheat hay diet did not differ significantly (P > 0.1), but was significantly higher than that of wheat hay diet (P < 0.05). The wheat hay diet could produce more propionic acid and ammonia nitrogen (P < 0.05) in the rumen, and reduce the ratio of acetic/propionic and nitrogen utilization. There was no significant difference in milk production among the three diets (P > 0.1). There was no significant difference in milk somatic cell count and body condition score among the three groups (P > 0.1). The wheat hay diet could significantly increase milk protein and lactose (P contents of interleukin-6 in cows fed alfalfa diet and alfalfa + wheat diet were significantly higher than that in cows fed wheat hay diet (P < 0.05). There was no significant difference in interleukinm-6 between in cows fed alfalfa diet and alfalfa + wheat diet (P > 0.05). The use of wheat hay to replace imported alfalfa in whole or in part could save feed costs. Full substitution of alfalfa with wheat hay could have a daily economic benefit of 13.74 yuan.

Risk prediction model for cutaneous squamous cell carcinoma in adult cardiac allograft recipients

BACKGROUND Heart transplant recipients are at higher risk of developing skin cancer than the general population due to the long-term immunosuppression treatment.Cancer has been reported as one of the major causes of morbidity and mortality for patients after heart transplantation.Among different types of skin cancers,cutaneous squamous cell carcinoma(cSCC)is the most common one,which requires timely screening and better management.AIM To identify risk factors and predict the incidence of cSCC for heart transplant recipients.METHODS We retrospectively analyzed adult heart transplant recipients between 2000 and 2015 extracted from the United Network for Organ Sharing registry.The whole dataset was randomly divided into a derivation set(80%)and a validation set(20%).Uni-and multivariate Cox regression were done to identify significant risk factors associated with the development of cSCC.Receiver operating characteristics curves were generated and area under the curve(AUC)was calculated to assess the accuracy of the prediction model.Based on the selected risk factors,a risk scoring system was developed to stratify patients into different risk groups.A cumulative cSCC-free survival curve was generated using the Kaplan-Meier method for each group,and the log-rank test was done to compare the intergroup cSCC rates.RESULTS There were 23736 heart-transplant recipients during the study period,and 1827 of them have been reported with cSCC.Significant predictors of post-transplant cSCC were older age,male sex,white race,recipient and donor human leukocyte antigen(HLA)mismatch level,malignancy at listing,diagnosis with restrictive myopathy or hypertrophic myopathy,heart re-transplant,and induction therapy with OKT3 or daclizumab.The multivariate model was used to predict the 5-,8-and 10-year incidence of cSCC and respectively provided AUC of 0.79,0.78 and 0.77 in the derivation set and 0.80,0.78 and 0.77 in the validation set.The risk scoring system assigned each patient with a risk score within the range of 0-11,based on which they were stratified into 4 different risk groups.The predicted and observed 5-year probability of developing cSCC match well among different risk groups.In addition,the log-rank test indicated significantly different cSCCfree survival across different groups.CONCLUSION A risk prediction model for cSCC among heart-transplant recipients has been generated for the first time.It offers a c-statistic of≥0.77 in both derivation and validation sets.

Cotyledons:a useful biological material for transient gene expression analysis in rapeseed(Brassica napus L.)

Polyethylene glycol (PEG)-mediated DNA transformation for transient gene expression in protoplasts and Agrobacterium tumefaciens-mediated transformation in lower epidermis of leaves are readily available in several plant species. In the study, these two versatile tools were used in rapeseed. A simple and efficient method was established for isolating protoplasts from rapeseed cotyledons and leaves, and found that cotyledons might be better than true leaves. Transient expression analysis showed that yellow fluorescent protein (YFP) and luciferase (LUC) could be expressed in rapeseed protoplasts. Moreover,GUS histochemical assays indicated that Agrobacterium-mediated DNA transient expression was achievable only in lower epidermis of rapeseed cotyledons and expression signal was the highest on the 5th day after injection with the bacterial suspension (OD600=0.8).These methods might provide valuable tools for rapid functional gene analysis in rapeseed.

Effective method for isolating liquid endosperm and improved procedure for subsequent DNA extraction in Brassica napus

The important agronomic traits of seed size and seed oil content in oilseed rape were af-fected by maternal effect. The maternal tissue endosperm, generated by fertilization of the diploid central cell in the female gametophyte, is essential for embryo and seed development. Imprinting is primarily re-stricted to the endosperm of flowering plants and is associated with differential DNA methylation of paren-tal alleles. Therefore, it is necessary to find out whether the endosperm influences these traits. If so, whether DNA methylation participated in these processes？ To answer these questions, isolation of pure liquid endosperm qualified for extraction genomic DNA and RNA was the prerequisite. However, it was not easy to conduct this isolation due to endosperm is encapsulated by tiny seed coat and it adjoins to de-veloping embryo. This research adopted a procedure for isolation pure lipid endosperm from 25DAF （days after flowering） ovules of Brassica napus and improved procedure for subsequent DNA extraction. With the optimized procedures, we successfully extracted genomic DNA of liquid endosperm from 500 mg o-vules with high concentration （ ≥2. 5μg/μl, 200μl） and high purity, which were proved by the subse-quent analysis.

审计质量:基于结果导向的测定

审计过程不可观测及审计报告标准化导致审计质量难以直接度量。因此,本文从结果导向思路,运用公开数据构建审计质量指标体系。首先,以审计准则对注册会计师工作总体目标界定为基础,本文认为财务报告是审计工作的重要产出,进而从工作质量、专业判断、努力程度三个维度构建审计质量指标;其次,阐述该指标体系的构建方法,并检验上述指标与融资约束、资本市场定价偏差的关系;最后,基于财务舞弊预测模型,检验该指标体系的应用效果。

Responses in splanchnic and mammary amino acid metabolism to short-term graded removal of methionine in lactating goats

Four multi-catheterized lactating goats were used in a 4×4 Latin square experiment to investigate the responses of amino acid metabolism in portal-drained viscera(PDV),liver,and mammary glands to short-term varying supplies of methionine(Met).During the last 45 h in each experimental period,goats were fasted for 12 h and then abomasally infused with an amino acid(AA)mixture plus glucose for 33 h.Treatments consisted of graded removal of Met from an infused AA mixture to achieve Met content in the infusate of 100%(complete),60%,30%,or 0%that in casein.Graded Met removal decreased the pro-duction of milk,milk protein,lactose,and fat linearly whilst also decreasing arterial Met concentration linearly(P<0.05).Meanwhile,net PDV uptake and liver removal of Met decreased linearly(P<0.05)due to decreased Met affinity of PDV and liver(P<0.05).Net mammary uptake of Met(P>0.1)was maintained as Met supply declined.This was achieved through increased mammary affinity(P<0.05)and increased mammary blood flow(P<0.05)totally offsetting the negative effect of decreased circu-lating Met concentration.Graded removal of Met from the infusate linearly decreased mammary uptake-to-milk output ratios of Met(P<0.05)and tended to decrease essential amino acid(EAA)linearly(0.05<P<0.1).Treatments also linearly decreased circulating concentration of prolactin and linearly increased insulin concentration(P<0.05).In conclusion,results of the present study indicated there were several mechanisms used to mitigate a Met deficiency,including reduced catabolism of Met in PDV,liver,and peripheral tissue(including mammary glands)and a linear increase in mammary blood flow.The observed decreases in milk protein production as Met supply decreased appear to be a result of regulatory events which may have been driven by decreased circulating prolactin,rather than as a result of decreased mammary Met uptake.