高效液相色谱法同时测定水产品中四种氟喹诺酮类药物残留前处理条件的优化

建立了同时测定水产品中氧氟沙星、诺氟沙星、环丙沙星、恩诺沙星4种氟喹诺酮类药物残留量的高效液相色谱方法,并对提取和净化等前处理条件进行了优化。目标化合物采用高效液相色谱-荧光检测器检测,外标法定量。对草鱼、鳙鱼、大黄鱼、虾进行检测分析,添加4、10、100、1000μg/kg浓度水平时,回收率为68.5%~106.6%,相对标准偏差0.80%~9.16%,方法的检出限为1.5μg/kg,定量限为4μg/kg。     

Detection of somaclonal variation in micro-propagated Echinacea purpurea using AFLP marker

This study used amplified fragment length polymorphism (AFLP) analysis to assess genetic fidelity between primary regenerants of Echinacea purpurea derived from leaf organogenesis and their donor plants. A total of 40 regenerants and 5 donors (T6-28-0, T3-23-0, T5-9-0, T2-15-0 and D7-4-0) were subjected to AFLP analysis using eight primer pairs. The results indicated that a total of 3805 scorable fragments were observed, of which 301 (9.40%) were polymorphic among the tested regenerants and donors probed with eight primer pairs. The percentage of polymorphic fragments within five donor groups averaged from 1.6% to 20.6%. Jaccard's similarity coefficients among regenerants and donors averaged from 0.9508 to 0.9935. However, only two regenerants (T2-15-2 and T2-15-3) had Jaccard's similarity coefficient value of 1 as comparing to their donor, thus they were true-to-type to their donor T2-15-0. It appears that AFLP is a sensitive and reliable molecular marker to detect possible somaclonal variation in micro-propagation system of E. purpurea. In vitro culture-induced somaclonal variation occurs in primary regenerants of E. purpurea derived from leaf organogenesis, though some of regenerants have genetic similarity greater than 0.99 in comparison with their donors.     

Artificial reefs as a reef restoration strategy in sediment‐affected environments: Insights from long‐term monitoring

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Microdistribution of metal elements in wood impregnated with a copper-chrome-arsenic preservative as determined by analytical electron microscopy

Summary The distribution of Cu, Cr and As in the walls of tracheids of Scots pine impregnated with Tanalith C at a retention of 2.5 lb/ft³ has been examined at the submicroscopic level in the electron microscope microanalyser, EMMA-4, using the absolute method, as well as in the conventional electron microscope. All three elements are present in all regions examined (probe area 0.2 m diameter). The concentration of Cu ranges from 0.4–0.9% (w/w), that of Cr is about 0.8%, while As ranges from 2%–2.6%. The morphology of this fine deposit is clearly dictated by the run of the cellulose microfibrils. There is in the wall an occasional coarse deposit, almost entirely copper, and the inner face of the tracheid wall is covered by a thin layer 20–30 m thick which contains all these elements at high concentration.     

Osthole suppresses hepatocyte growth factor (HGF)-induced epithelial-mesenchymal transition via repression of the c-Met/Akt/mTOR pathway in human breast cancer cells

Substantial activation of the HGF/c-Met signaling pathway is involved in the progression of several types of cancers and associated with increased tumor invasion and metastatic potential. Underlying HGF-induced tumorigenesis, epithelial to mesenchymal transition (EMT) shows a positive correlation with progression in patients. We previously determined that osthole is a potent fatty acid synthase (FASN) inhibitor. FASN is implicated in cancer progression and may regulate lipid raft function. We therefore examined whether osthole could block HGF-induced tumorigenesis by disrupting lipid rafts. Here, we found that osthole could abrogate HGF-induced cell scattering, migration, and invasion in MCF-7 breast cancer cells. Osthole also effectively inhibited the HGF-induced decrease of E-cadherin and increase of vimentin via down-regulation of phosphorylated Akt and mTOR. Interestingly, osthole blocked HGF-induced c-Met phosphorylation and repressed the expression of total c-Met protein in MCF-7 cells. In addition, C75, a pharmacological inhibitor of FASN, repressed the expression of total c-Met protein in MCF-7 cells. Consistent with a role for FASN, loss of c-Met in cells treated with osthole was prevented by the exogenous addition of palmitate. Briefly, our result suggests a connection between FASN activity and c-Met protein expression and that osthole is a potential compound for breast cancer therapy by targeting the major pathway of HGF/c-Met-induced EMT.     

Inhibitory effect of α-lipoic acid on platelet aggregation is mediated by PPARs

Peroxisome proliferator-activated receptors (PPARs) isoforms (α, β/δ, and γ are present in human platelets, and activation of PPARs inhibits platelet aggregation. α-Lipoic acid (ALA), occurring naturally in human food, has been reported to exhibit an antiplatelet activity. However, the mechanisms underlying ALA-mediated inhibition of platelet aggregation remain unknown. The aim of this study was to investigate whether the antiplatelet activity of ALA is mediated by PPARs. ALA itself significantly induced PPARα/γ activation in platelets and increased intracellular amounts of PPARα/γ by blocking PPARα/γ secretion from arachidonic acid (AA)-activated platelets. Moreover, ALA significantly inhibited AA-induced platelet aggregation, Ca(2+) mobilization, and cyclooxygenase-1 (COX-1) activity, but increased cyclic AMP production in rabbit washed platelets. Importantly, ALA also enhanced interaction of PPARα/γ with protein kinase Cα (PKCα) and COX-1 accompanied by an inhibition of PKCα activity in resting and AA-activated platelets. However, the above effects of ALA on platelets were markedly reversed by simultaneous addition of selective PPARα antagonist (GW6471) or PPARγ antagonist (GW9662). Taken together, the present study provides a novel mechanism by which ALA inhibition of platelet aggregation is mediated by PPARα/γ-dependent processes, which involve interaction with PKCα and COX-1, increase of cyclic AMP formation, and inhibition of intracellular Ca(2+) mobilization.     

Interference prevention in size-exclusion chromatographic analysis of debranched starch glucans by aqueous system

Branch chain-length distribution of amylopectin plays an important role on the characteristics of starch. One of the adapted protocols for determining the chain-length distribution and mass proportion of starch molecules is that starch is debranched with isoamylase and then analyzed by using high-performance size-exclusion chromatography coupled with multiangle laser-light scattering and refractive index detection (HPSEC-MALS-RI). However, ammonium sulfate in commercial isoamylase and acetate in debranching buffer give significant interferences on the chromatograms because of their undesirable ionic interactions with column sorbent materials. This study deals with development for correcting those interferences. A weak anion-exchange resin or selective precipitation with barium acetate was employed to remove sulfate prior to HPSEC determination. The interference of acetate was overcome by means of high ionic strength eluent, 0.3 M sodium nitrate. The specific refractive index increment (dn/dc) of amylodextrin was determined to be 0.147 using the modified conditions and was applied to calculate the molecular weight distribution of debranched starch molecules.     

应用复合多聚酶链反应方法快速鉴别伪狂犬病弱毒疫苗与野毒

本研究根据伪狂犬病病毒（ＰｒＶ）共有ｇＢ和疫苗株缺失的ｇＥ基因序列分别设计合成１对通用（ＰＢ１／ＰＢ２）和１对鉴别引物（ＰＥ１／ＰＥ２）,以在我国广泛使用的疫苗株Ｂａｒｔｈａ－Ｋ６１及从国内外收集的野毒株Ｓ、ＳＵ、Ｆ、Ｌ、Ｙ、Ｍｉｎ－Ａ、Ｓｈｏｐｅ、Ｓ（川）、ＳＬ１、１０＃、ＥＡ（鄂Ａ）ＤＮＡ为模板在同一反应管中同时扩增ｇＢ和ｇＥ基因序列建立了复合多聚酶链反应（ＰＣＲ）方法。ＰＣＲ产物经２．０％琼     

Effects of Glucose Concentration on in vitro Fertilization in BALB/c Mice

BALB/c mice are widely used in genetic, tumour and immunological studies. However, the mice demonstrate a lower reproduction rate, low fertility and small litters, because of their highly genetic homozygoisty. Based on in vitro fertilization (IVF), a routine technique for biomedical studies, it is worth to evaluate the effects to BALB/c mice on IVF efficiency. In order to test the genetic factor affecting the IVF efficiency of BALB/c, four reciprocal IVF tests of BALB/cByJ and FVB/NCrl mice were performed. The results showed that the average fertility of IVF sponsored by FVB/NCrl spermatozoa was 69.6%, but only 12.1% was obtained from BALB/cByJ strain. Effect of glucose contained in the culture medium to the IVF efficiency of BALB/cByJ was also evaluated. The results showed that the fertility of BALB/cByJ spermatozoa incubated with 0, 2.7, 5.5, 11.1 and 22.2 mm of glucose in the TYH medium were 6.8, 9.9, 13.9, 32.7 and 22.2%, respectively. It is showed that IVF efficiency of BALB/cByJ spermatozoa could be improved depending on the concentration of glucose in the IVF medium. According to the results, it is beleived that lower IVF of BALB/cByJ mice might be due to the genetic defect in spermatozoa and increasing glucose in the IVF medium which significantly affect the IVF efficiency of BALB/cByl via activating the spermatozoa.     

The Efficacy of Inactivated Photobacterium damselae subsp. piscicida Combined with Levan/Alum as Vaccine against Photobacteriosis in Cobia,Rachycentron canadum

Photobacterium damselae subsp. piscicida (Phdp) is a major pathogen of cultured cobia (Rachycentron canadum), a primary target species for offshore cage culture in Taiwan. Serum antibody titers as well as efficiency and duration of protection against Phdp were evaluated following intraperitoneal administration of a candidate vaccine prepared with formalin‐inactivated whole cells in combination with levan/alum adjuvants. The results showed vaccinates delayed the disease onset and had significantly (P < 0.05) less mortality than control nonvaccinates during Days 21–105 postvaccination with highest relative percentage of survival (RPS) and antibody titer up to 81.4% and 1:614, respectively. There was a highly significant positive linear correlation between the RPS and antibody titer (R² = 0.841). Long‐lasting and significant protection against Phdp can be achieved with inactivated Phdp plus levan/alum, a potential cobia vaccine against photobacteriosis. Levan/alum complex may represent a promising adjuvant formula for the development of a Phdp vaccine.