Construction of specific Smo lentivirus and expression of infected pancreatic cancer cells positive for CD24CD44 surface antibody

This study aimed to construct a vector lentivirus carrying the Smo gene and transfect pancreatic cancer cells positive for CD24CD44 surface antibody and detect the infectivity. A lentivirus carrying a specific Smo fragment was designed and synthesized, and its functionality was tested. An overexpression group, inhibitory group, and negative control group were used for subsequent experimental research and comparison. A virus was successfully designed and produced. The best viral load was the 1X106 TU virus, where the cell growth and fluorescence effect of culture wells with polybrene dilution were the best. These are the transfection conditions and transfection param-eters for subsequent experiments. This plasmid was detected with a flag antibody by Western blot. The result was that it had a large specific 250kD band, and the membrane protein was overexpressed successfully. The expression results of Smo in five groups of cells after virus transfection detected by RT-PCR: blank group were 1.0038±0.0344, CON238 negative group: 1.0276±0.2944d, CON077 negative group: 0.8793±0.0402; LV-SMO15570-2 overexpres-sion group: 2.7479±0.8308, and LV-SMO-RNAi37304-1 inhibition group: 0.2386±0.0481. There were differences among the overexpression group and inhibition group with the other three groups. Homogeneity of variance: Bartlett F = 4.3530, P = 0.0016 < 0.05, heterogeneous. K-W test: cc2 = 10.9905* P = 0.0267, and there was a statisti-cally significant difference. The designed virus achieved the goal requirements. An sRNA fragment was designed for the key gene Smo of the Hh signaling pathway, and a vector lentivirus carrying this fragment was successfully constructed. The expression of Smo was analyzed after transfecting SW1990CD24CD44 positive cells, suggesting that the function of the RNA fragment designed for the key gene Smo in this experiment was successful.

Chronic exposure to low levels of aluminum alters cerebral cell signaling in response to acute MPTP administration

Two-month-old male B/6C3F1 mice were treated for 10 weeks with 100 μM aluminum lactate (Al) in drinking water. This dose of Al did not alter body weight, and there was no evidence of systemic toxicity. The degree of phosphorylation of several kinases which lead to transcription factor activation (reflecting the extent of their activation) was studied. The proportion of extracellular signal-regulated kinase (ERK) that was activated was depressed in cortex but not in the hippocampus following treatment but c-Jun N-terminal kinase (JNK), p38, IκB phosphorylation was unaltered in either tissue. Treatment of mice with 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP) alone produced no significant changes in the degree of activation of any transcription factor studied. When MPTP dosing had been preceded by extended exposure to low levels of Al in drinking water, ERK activation was profoundly depressed in cortex and hippocampus, whereas JNK in hippocampus and IκB in cortex were greatly elevated. These changes consequent to exposure to both Al and MPTP were accompanied by an increase in NF-κB in both regions, whereas AP-1 was elevated in the hippocampus alone. Neither agent alone modulated AP-1 or NF-κB. Thus a synergistic interaction occurred between the toxicants. This interaction tended to promote the functioning of a kinase largely associated with inflammation and to depress that of ERK, which is associated with maintenance of cell survival. It is concluded that exposure to levels of Al with no evident toxicity can worsen the response to an acute challenge with MPTP. Al treatment alone was able to increase striatal 3,4-dihydroxyphenylacetic acid levels, suggesting an elevation of the rate of dopamine turnover in the striatum. However, no interaction in alteration of monoamine levels was found between Al and MPTP.

Establishment, Differentiation, Electroporation and Nuclear Transfer of Porcine Mesenchymal Stem Cells

The limited success of somatic cell nuclear transfer (SCNT) is largely attributed to defects in epigenetic reprogramming of the donor genome. Donor cell types with distinct potential competence may offer different epigenetic flexibility for subsequent genome reprogramming in SCNT. Stem cells possibly enable their genomes to be more readily reprogrammed than differentiated cells. To improve the efficiency of cloning, porcine mesenchymal stem cells (pMSCs) were isolated and well identified by 6-channel flow cytometry and differentiation assays and were used as donors in SCNT. Compared with porcine embryonic fibroblasts (pEFs), our results showed that pMSCs markedly enhanced cloned embryo development in terms of cleavage and blastocyst formation (p < 0.05). To enhance the epigenetic flexibility of pMSCs, classical reprogramming factors (RFs) were transfected by electroporation, and we achieved optimization with ectopic expression of RFs in pMSCs. Our results suggest that the epigenetic status of donor cells has an improvement on genome reprogramming, and multipotent pMSCs favoured subsequent embryonic development.

A chronic generalized bi-directional brain-machine interface

A bi-directional neural interface (NI) system was designed and prototyped by incorporating a novel neural recording and processing subsystem into a commercial neural stimulator architecture. The NI system prototype leverages the system infrastructure from an existing neurostimulator to ensure reliable operation in a chronic implantation environment. In addition to providing predicate therapy capabilities, the device adds key elements to facilitate chronic research, such as four channels of electrocortigram/local field potential amplification and spectral analysis, a three-axis accelerometer, algorithm processing, event-based data logging, and wireless telemetry for data uploads and algorithm/configuration updates. The custom-integrated micropower sensor and interface circuits facilitate extended operation in a power-limited device. The prototype underwent significant verification testing to ensure reliability, and meets the requirements for a class CF instrument per IEC-60601 protocols. The ability of the device system to process and aid in classifying brain states was preclinically validated using an in vivo non-human primate model for brain control of a computer cursor (i.e. brain-machine interface or BMI). The primate BMI model was chosen for its ability to quantitatively measure signal decoding performance from brain activity that is similar in both amplitude and spectral content to other biomarkers used to detect disease states (e.g. Parkinson's disease). A key goal of this research prototype is to help broaden the clinical scope and acceptance of NI techniques, particularly real-time brain state detection. These techniques have the potential to be generalized beyond motor prosthesis, and are being explored for unmet needs in other neurological conditions such as movement disorders, stroke and epilepsy.

Effects of cholesterol on CCK-1 receptors and caveolin-3 proteins recycling in human gallbladder muscle

The contraction of gallbladders (GBs) with cholesterol stones is impaired due to high cholesterol concentrations in caveolae compared with GBs with pigment stones. The reduced contraction is caused by a lower cholecystokinin (CCK)-8 binding to CCK-1 receptors (CCK-1R) due to caveolar sequestration of receptors. We aimed to examine the mechanism of cholesterol-induced sequestration of receptors. Muscle cells from human and guinea pig GBs were studied. Antibodies were used to examine CCK-1R, antigens of early and recycling endosomes, and total (CAV-3) and phosphorylated caveolar-3 protein (pCAV-3) by Western blots. Contraction was measured in muscle cells transfected with CAV3 mRNA or clathrin heavy-chain small-interfering RNA (siRNA). CCK-1R returned back to the bulk plasma membrane (PM) 30 min after CCK-8 recycled by endosomes, peaking at 5 min in early endosomes and at 20 min in recycling endosomes. Pretreatment with cholesterol-rich liposomes inhibited the transfer of CCK-1R and of CAV-3 in the endosomes by blocking CAV-3 phosphorylation. 4-Amino-5-(4-chloro-phenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (inhibitor of tyrosine kinase) reproduced these effects by blocking pCAV-3 formation, increasing CAV-3 and CCK-1R sequestration in the caveolae and impairing CCK-8-induced contraction. CAV-3 siRNA reduced CAV-3 protein expression, decreased CCK-8-induced contraction, and accumulated CCK-1R in the caveolae. Abnormal concentrations of caveolar cholesterol had no effect on met-enkephalin that stimulates a delta-opioid receptor that internalizes through clathrin. We found that impaired muscle contraction in GBs with cholesterol stones is due to high caveolar levels of cholesterol that inhibits pCAV-3 generation. Caveolar cholesterol increases the caveolar sequestration of CAV-3 and CCK-1R caused by their reduced recycling to the PM.

WNK4 regulates the secretory pathway via which TRPV5 is targeted to the plasma membrane

TRPV5 and TRPV6 are two closely related epithelial calcium channels that mediate apical calcium entry in the transcellular calcium transport pathway. TRPV5, but not TRPV6, is enhanced by protein kinase WNK4 when expressed in Xenopus laevis oocytes. We report that the majority of human TRPV5 exogenously expressed in the Xenopus oocyte plasma membrane was complexly N-glycosylated whereas that for human TRPV6 was core-glycosylated. Unglycosylated N358Q mutants of TRPV5 and TRPV6 were able to be expressed in the plasma membrane albeit with decreased abilities in mediating calcium uptake. Syntaxin 6, a SNARE protein in the trans-Golgi network, blocked the complex glycosylation of TRPV5 and TRPV6, rendered the channels in core-glycosylated form. Blocking complex glycosylation of TRPV5 either by syntaxin 6 or by N358Q mutation abolished the enhancing effect of WNK4 on TRPV5. Thus the difference in membrane expression of TRPV5 and TRPV6 explains the selective effect of WNK4 on TRPV5, which is likely on the secretory pathway involving complex glycosylation of channel proteins.

[Preoperative superselective intra-internal iliac arterial chemotherapy for invasive bladder cancer and curative analysis]

OBJECTIVE

To study clinical effects of preoperative intra-internal iliac-arterial chemotherapy for invasive bladder cancer.

METHODS

14 cases of invasive bladder cancer underwent superselective intra-internal iliac-arterial chemotherapy before conservative cystectomy.

RESULTS

After 2-3 week therapy, reduction of cancer volume (20%-50%), clotted by thrombus in the blood vessels of the cancer or circumferential tissue, and decreased bleeding were found. Pathomorphological features included large patchy necrosis, degeneration, and inflammatory changes of carcinoma tissue. Follow-up ranged from 5 to 42 months (mean 19.6 months). One T3 N1 M0) of the cases (0.7%) relapsed into T1N0M0 and the others did not.

CONCLUSIONS

The intra-internal iliac-arterial method, simple, safe, coordinates in pre-operation for invasive bladder cancer, and increases the operative opportunity for preservation of functional bladder.

Combinatorial discovery of oxidative dehydrogenation catalysts within the Mo-V-Nb-O system

Combinatorial methodologies were used for the synthesis and screening of mixed metal oxide heterogeneous catalysts. Primary screening at low reactant conversions at a throughput of greater than 10,000 catalyst compositions per month was performed by using simultaneous MS and photothermal deflection spectroscopy on spatially separated thick film catalysts with approximately 200 microg per catalyst prepared by using automated liquid dispensing. Secondary screening under realistic operating conditions was performed at a throughput of greater than 3,000 catalyst compositions per month on approximately 50 mg of catalyst in an array of fixed bed microreactors with gas chromatograph detection. The approach was validated by the discovery of catalysts with superior performance to those previously described for the oxidative dehydrogenation of ethane to ethylene. We show the full implementation and integration of combinatorial methodologies for synthesis, screening, discovery, and optimization of multicomponent heterogeneous catalysts.

Short Communication: An apospory-specific genomic region is conserved between Buffelgrass (Cenchrus ciliaris L.) and Pennisetum squamulatum Fresen

Twelve molecular markers linked to pseudogamous apospory, a form of gametophytic apomixis, were previously isolated from Pennisetum squamulatum Fresen. No recombination between these markers was found in a segregating population of 397 individuals (Ozias-Akins et al. 1998, Proc. Natl Acad. Sci. USA, 95, 5127-5132). The objective of the present study was to test if these markers were also linked to the aposporous mode of reproduction in two small segregating populations of Cenchrus ciliaris (= Pennisetum ciliare (L.)Link), another apomictic grass species. Among 12 markers (sequence characterized amplified regions, SCARs), six were scored as dominant markers between aposporous and sexual C. ciliaris genotypes (presence/absence, respectively). Five were always linked to apospory and one showed a low level of recombination in 84 progenies. Restriction fragment length polymorphisms (RFLPs) were observed between sexual and apomictic phenotypes for three of the six remaining SCARs from P. squamulatum when used as probes. No recombination was observed in the F1 progenies. Preliminary data from megabase DNA analysis and sequencing in both species indicate that an apospory-specific genomic region (ASGR) is highly conserved between the two species. Although C. ciliaris has a smaller genome size to P. squamulatum, a higher copy number for markers linked to apospory found in the former may impair the progress of positional cloning of gene(s) for apomixis in this species.

[Chemical constituents of fructus Amomi]

Seven compounds have been isolated from Fructus Amomi. They were identified as bornyl acetate, camphor, borneol, beta-sitosterol, vanillic acid, stearic acid and palmitic acid. The vanillic acid was found in this medicine for the first time. Fifty-seven components were identified from the volatile oil of Fructus Amomi on the basis of GC-MS analysis. Eight components in the volatile oil over 1% in content are bornyl acetate, camphor, borneol, limonene, camphene, myrecene, carene-3 and alpha-terpeneol.

Mutational analysis of mRNA capping enzyme identifies amino acids involved in GTP binding, enzyme-guanylate formation, and GMP transfer to RNA

Vaccinia virus mRNA capping enzyme is a multifunctional protein with RNA triphosphatase, RNA guanylyltransferase, RNA (guanine-7) methyltransferase, and transcription termination factor activities. The protein is a heterodimer of 95- and 33-kDa subunits encoded by the vaccinia virus D1 and D12 genes, respectively. The capping reaction entails transfer of GMP from GTP to the 5'-diphosphate end of mRNA via a covalent enzyme-(lysyl-GMP) intermediate. The active site is situated at Lys-260 of the D1 subunit within a sequence element, KxDG (motif I), that is conserved in the capping enzymes from yeasts and other DNA viruses and at the active sites of covalent adenylylation of RNA and DNA ligases. Four additional sequence motifs (II to V) are conserved in the same order and with similar spacing among the capping enzymes and several ATP-dependent ligases. The relevance of these common sequence elements to the RNA capping reaction was addressed by mutational analysis of the vaccinia virus D1 protein. Nine alanine substitution mutations were targeted to motifs II to V. Histidine-tagged versions of the mutated D1 polypeptide were coexpressed in bacteria with the D12 subunit, and the His-tagged heterodimers were purified by Ni affinity and phosphocellulose chromatography steps. Whereas each of the mutated enzymes retained triphosphatase, methyltransferase, and termination factor activities, six of nine mutant enzymes were defective in some aspect of transguanylylation. Individual mutations in motifs III, IV, and V had distinctive effects on the affinity of enzyme for GTP, the rate of covalent catalysis (EpG formation), or the transfer of GMP from enzyme to RNA. These results are concordant with mutational studies of yeast RNA capping enzyme and suggest a conserved structural basis for covalent nucleotidyl transfer.

The D1 and D12 subunits are both essential for the transcription termination factor activity of vaccinia virus capping enzyme

Transcription termination by vaccinia virus RNA polymerase during synthesis of early mRNAs requires a virus-encoded termination factor (VTF). VTF is but one of many activities associated with the vaccinia virus mRNA capping enzyme, a heterodimer of 95- and 33-kDa subunits encoded by the D1 and D12 genes, respectively. Although the three catalytic domains involved in cap formation have been assigned to individual subunits or portions thereof, the structural requirements for VTF activity are unknown. We now report that both full-length subunits are required for transcription termination. The 844-amino acid D1 subunit by itself, which is fully active in triphosphatase and guanylyltransferase functions, has no demonstrable VTF activity in vitro. Neither does the D12 subunit by itself. The heterodimeric methyltransferase domain of D1 (residues 498 to 844) and D12 subunits also has no VTF activity. VTF is not affected by a K-to-M mutation of the guanylyltransferase active site at position 260 (K260M) that abolishes enzyme-GMP complex formation or by a H682A/Y683A double mutation of the D1 subunit, which abrogates methyltransferase activity. Thus, the structural requirements for termination are distinct from those for nucleotidyl transfer and methyl transfer.

Covalent catalysis in nucleotidyl transfer. A KTDG motif essential for enzyme-GMP complex formation by mRNA capping enzyme is conserved at the active sites of RNA and DNA ligases

Vaccinia virus RNA capping enzyme, a heterodimer of 95- and 31-kDa subunits, catalyzes transfer of GMP from GTP to the 5'-diphosphate terminus of RNA via a covalent enzyme-guanylate intermediate. The GMP residue is attached to the 95-kDa subunit through a phosphoamide bond to the epsilon-amino group of a lysine residue. The amino acid sequence of the large subunit includes a lysine-containing motif, Tyr-X-X-X-Lys260-Thr-Asp-Gly, that is conserved in the RNA guanylyltransferases encoded by Shope fibroma virus and Saccharomyces cerevisiae. The KXDG motif is also encountered at the sites of covalent adenylylation of bacteriophage T4 RNA ligase and mammalian DNA ligase I (Thogerson, H. C., Morris, H. R., Rand, K. N., and Gait, M. J. (1985) Eur. J. Biochem. 147, 325-329; Tomkinson, A. E., Totty, N. F., Ginsburg, M., and Lindahl, T. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 400-404). We find that conservative amino acid substitutions at three out of four positions within the KTDG sequence of vaccinia capping enzyme either prevent or strongly inhibit enzyme-guanylate formation. The conserved motif is therefore an essential component of the guanylyltransferase domain. Lys260 is implicated as the active site. Comparison of the sequences of capping enzymes and polynucleotide ligases from diverse sources suggests that KX(D/N)G may be a signature element for covalent catalysis in nucleotidyl transfer.

Methyltransferase and subunit association domains of vaccinia virus mRNA capping enzyme

RNA triphosphatase, RNA guanylyltransferase, and RNA (guanine-N7-)-methyltransferase activities are associated with the vaccinia virus mRNA capping enzyme, a heterodimeric protein containing polypeptides of M(r) 95,000 and 31,000. Although the RNA triphosphatase and RNA guanylyltransferase domains have been localized to a M(r) 59,000 fragment of the capping enzyme large subunit, the location of the methyltransferase domain within the protein and the catalytic role of individual subunits in methyl group transfer remain unclear. In the present work, through the study of methyltransferase activity of truncated forms of capping enzyme translated in vitro in a rabbit reticulocyte lysate, we have localized the methyltransferase domain to a complex consisting of the small subunit and the carboxyl-terminal portion of the large subunit. The M(r) 31,000 subunit translated alone was not sufficient for methyltransferase activity. This requirement for both subunits may explain the tight physical association of the two polypeptides in vivo. We have recreated the association of the large and small enzyme subunits in vitro through the translation of synthetic mRNAs encoding the two polypeptides. Study of the ability of deleted versions of the large subunit to bind the small subunit, as detected by co-immunoprecipitation, defined a 347-amino acid carboxyl-terminal region of the large subunit that was sufficient for heterodimerization. Colocalization within the large subunit of the methyltransferase and subunit association domains suggests that dimerization of the subunits may be required for methyltransferase activity.