Development of a pronuclear DNA microinjection technique for production of green fluorescent protein-expressing bubaline (Bubalus bubalis) embryos

Oocytes from abattoir-derived bubaline (Bubalus bubalis) ovaries were subjected to IVM and IVF; the objective was to develop a pronuclear DNA microinjection technique to produce embryos expressing green fluorescent protein (GFP). The largest proportion (61.2%) of zygotes in which one (1 PN) or two pronuclei (2 PN) were visible was when centrifugation (14,000 x g for 15 min) was done 16 h after insemination. Centrifugation had no adverse effects on cleavage rate, development to morulae/blastocysts, and total cell number of embryos. Piercing the pronuclear but not the plasma membrane reduced (P<0.05) cleavage rate (44.0% vs. 51.0%), without affecting subsequent development. Following microinjection of a GFP-DNA construct, cleavage rate (55.9, 38.9, and 30.9%) and proportion of cleaved embryos that developed to morulae (39.9, 25.6, and 15.5%) and blastocyst stages (22.4, 13.4, and 2.8%) were higher (P<0.05) for non-injected controls than for those injected with buffer alone, which, in turn, were higher (P<0.05) than for those injected with buffer containing 5 microg/mL DNA. The cleavage rate (39.2% vs. 34.8%) and proportion of cleaved embryos that developed to morulae/blastocysts (37.5% vs. 10.9%) were higher (P<0.05) for microinjected zygotes with 2 PN than for those with 1 PN. The cleavage rate and the proportion of cleaved embryos that developed to morulae and blastocysts were higher (P<0.05) following culture of microinjected zygotes in mCR2aa medium (40.7, 32.7, and 9.1%, respectively) compared to those for mSOFaa (33.3, 26.0, and 6.5%, respectively) or after culture in TCM-199+co-culture with buffalo oviductal epithelial cells (31.2, 25.0, and 4.5%, respectively). The proportion of embryos expressing GFP was higher (P<0.01) for 2 PN than for 1 PN zygotes (15.9% vs. 13.7%). Thirty-five embryos expressed GFP; the proportion of mosaic embryos (62.8%) was higher (P<0.01) than of embryos in which all blastomeres expressed GFP (37.2%); eight and two of those embryos developed to the morula and blastocyst stages, respectively.     

Changes in follicular populations following treatment of buffaloes with PMSG (eCG) and Neutra-PMSG for superovulation.

Some 19 buffaloes were synchronized by administration of a prostaglandin (PG) salt Lutalyse, with a single intramuscular (i.m.) injection of 25 mg at day -13. Luteolysis was induced by administration of 50 mg PG, in divided doses of 30 and 20 mg i.m. 12 h apart on day 0 of experiment. The 30 mg PG injection was designated as 0 h of experiment. Group I animals (n = 6) received saline and served as controls while animals in Groups II (n = 7) and III (n = 6) received 2500 I.U. PMSG (eCG) i.m. at day -2. Group III animals were administered 5 ml Neutra-eCG intravenously at 60 h. The number of follicles, classified on the basis of diameter as small (2-5 mm), medium (6-9 mm) and large (> or = 10 mm) was assessed by ultrasonography on days -2, -1, 0, 1, 2, 5 and 7 of experiment. The number of corpora lutea (CL) was recorded by palpation per rectum on day 8. The number of small follicles which did not differ among the three groups on days 0, 1 and 2 was significantly lower (P < 0.05) in Group II animals compared to those in Groups I and III on days 5 and 7. The number of medium follicles increased after eCG treatment and was significantly higher (P < 0.05) in animals of Groups II and III on days 0 and 1, compared to control animals of Group I. It was, however, not different among the three groups on subsequent days of experiment. The number of large follicles which did not differ among the three groups on days -2, 0, 1 and 2 was significantly higher in Groups II (P < 0.01) and III (P < 0.05) animals compared to those of Group I on day 5. On day 7, the number of large follicles was in the order (P < 0.05) Group II > Group III > Group I. The number of CL in Group II animals was significantly higher (P < 0.05) than that in Group I animals but was not different from that of Group III animals. These results suggest that treatment of buffaloes with eCG for superovulation reduces the number of small follicles and increases the number of large follicles 5-7 days after PG treatment. Administration of Neutra-eCG 60 h after PG treatment can partly reverse this trend but has no effect on ovulation rate. The possibility that part of the variability in ovulation rates in this study may have resulted from Neutra-eCG been given prior to or at the LH surge, or from the absence or presence of a dominant follicle at the time of eCG treatment cannot be ruled out.     

降解烤烟秸秆和烟碱菌株的筛选及其产酶特性

摘要:【目的】为获得能够降解烤烟秸秆和烟碱的菌株,并探索其降解烤烟秸秆的利用途径。【方法】以烤烟秸秆为唯一碳氮源,从烟田土壤中进行了菌株的筛选。采用形态学观察、生理生化特性鉴定、16S rRNA基因序列鉴定等方法对该菌株进行了鉴定,并对其以烤烟秸秆为底物进行液态发酵的产酶活性和木质纤维素降解效果进行了测定。【结果】结果表明:该菌株为巨大芽孢杆菌(Bacillus megaterium)。在以烤烟秸秆为主要营养物质液态发酵条件下该菌株具有较强的木质素降解能力,最大漆酶活力达到418.52 U/L,而木质素过氧化物酶和锰过氧化物酶的最大酶活分别为19.71 U/L 和64.71 U/L。此外,发酵20 d后该菌能够完全降解发酵液中的烟碱。【结论】本研究筛选到了1株能够较好降解烤烟秸秆和完全降解烟碱的巨大芽孢杆菌(Bacillus megaterium),且该菌株具有利用烤烟秸秆生产漆酶的应用价值。     

Triterpenoids of Scoparia dulcis

The triterpenoids of Scoparia dulcis were identified as friedelin, glutinol, α-amyrin, betulinic acid, ifflaionic acid and dulcioic acid.     

Regulation and function of the two-pore-domain (K2P) potassium channel Trek-1 in alveolar epithelial cells

Hyperoxia can lead to a myriad of deleterious effects in the lung including epithelial damage and diffuse inflammation. The specific mechanisms by which hyperoxia promotes these pathological changes are not completely understood. Activation of ion channels has been proposed as one of the mechanisms required for cell activation and mediator secretion. The two-pore-domain K(+) channel (K2P) Trek-1 has recently been described in lung epithelial cells, but its function remains elusive. In this study we hypothesized that hyperoxia affects expression of Trek-1 in alveolar epithelial cells and that Trek-1 is involved in regulation of cell proliferation and cytokine secretion. We found gene expression of several K2P channels in mouse alveolar epithelial cells (MLE-12), and expression of Trek-1 was significantly downregulated in cultured cells and lungs of mice exposed to hyperoxia. Similarly, proliferation cell nuclear antigen (PCNA) and Cyclin D1 expression were downregulated by exposure to hyperoxia. We developed an MLE-12 cell line deficient in Trek-1 expression using shRNA and found that Trek-1 deficiency resulted in increased cell proliferation and upregulation of PCNA but not Cyclin D1. Furthermore, IL-6 and regulated on activation normal T-expressed and presumably secreted (RANTES) secretion was decreased in Trek-1-deficient cells, whereas release of monocyte chemoattractant protein-1 was increased. Release of KC/IL-8 was not affected by Trek-1 deficiency. Overall, deficiency of Trek-1 had a more pronounced effect on mediator secretion than exposure to hyperoxia. This is the first report suggesting that the K(+) channel Trek-1 could be involved in regulation of alveolar epithelial cell proliferation and cytokine secretion, but a direct association with hyperoxia-induced changes in Trek-1 levels remains elusive.     

A lipophilic thioflavin-T derivative for positron emission tomography (PET) imaging of amyloid in brain

The synthesis of a new lipophilic thioflavin-T analogue (2-[4' -(methylamino)phenyl]benzothiazole, 6) with high affinity for amyloid is reported. Intravenous injection of [(11)C]-labeled 6 in control mice resulted in high brain uptake. Amyloid deposits were imaged with multiphoton microscopy in the brains of living transgenic mice following the systemic injection of unlabeled 6. [(11)C]6 is a promising amyloid imaging agent for Alzheimer's disease.     

Membrane Phospholipid Augments Cytochrome P4501a Enzymatic Activity by Modulating Structural Conformation during Detoxification of Xenobiotics

Cytochrome P450 is a superfamily of membrane-bound hemoprotein that gets involved with the degradation of xenobiotics and internal metabolites. Accumulated body of evidence indicates that phospholipids play a crucial role in determining the enzymatic activity of cytochrome P450 in the microenvironment by modulating its structure during detoxification; however, the structure-function relationship of cytochrome P4501A, a family of enzymes responsible for degrading lipophilic aromatic hydrocarbons, is still not well defined. Inducibility of cytochrome P4501A in cultured catfish hepatocytes in response to carbofuran, a widely used pesticide around the world, was studied earlier in our laboratory. In this present investigation, we observed that treating catfish with carbofuran augmented total phospholipid in the liver. We examined the role of phospholipid on the of cytochrome P4501A-marker enzyme which is known as ethoxyresorufin-O-deethylase (EROD) in the context of structure and function. We purified the carbofuran-induced cytochrome P4501A protein from catfish liver. Subsequently, we examined the enzymatic activity of purified P4501A protein in the presence of phospholipid, and studied how the structure of purified protein was influenced in the phospholipid environment. Membrane phospholipid appeared to accelerate the enzymatic activity of EROD by changing its structural conformation and thus controlling the detoxification of xenobiotics. Our study revealed the missing link of how the cytochrome P450 restores its enzymatic activity by changing its structural conformation in the phospholipid microenvironment.     

Production of interspecies handmade cloned embryos by nuclear transfer of cattle, goat and rat fibroblasts to buffalo (Bubalus bubalis) oocytes

The possibility of producing interspecies handmade cloned (iHMC) embryos by nuclear transfer from donor cells of cattle, goat and rat using buffalo oocytes as recipient cytoplasts was explored. Zona-free buffalo oocytes were enucleated by protrusion cone-guided bisection with a microblade. After electrofusion with somatic cells, reconstructed oocytes were activated by calcimycin A23187, treated with 6-dimethylaminopurine and were cultured in K-RVCL-50^® medium for 8 days. Although the cleavage rate was not significantly different when buffalo, cattle, goat or rat cells were used as donor nuclei (74.6 ± 3.8, 82.8 ± 5.3, 86.0 ± 4.9 and 82.3 ± 3.6%, respectively), the blastocyst rate was significantly higher (P < 0.01) for buffalo (51.4 ± 2.6) than for cattle (3.5 ± 1.0) or the goat (2.2 ± 0.9), whereas none of the embryos crossed the 32-cell stage when rat cells were used. However, the total cell number was similar for buffalo–buffalo (175.0 ± 5.07) and cattle–buffalo embryos (178.0 ± 11.84). Following transfer of 3 buffalo–buffalo embryos each to 6 recipients, 3 were found to be pregnant, though the pregnancies were not carried to full term. These results suggest that interspecies blastocyst stage embryos can be produced by iHMC using buffalo cytoplasts and differentiated somatic cells from cattle and goat and that the source of donor nucleus affects the developmental competence of interspecies embryos.