A missense mutation G2320R in the thyroglobulin gene causes non-goitrous congenital primary hypothyroidism in the WIC-rdw rat

A convincing line of evidence is being developed that the congenital nongoitrous hypothyroidism and dwarfism observed in the WIC-rdw rat may indeed be caused by a primary defect in thyroid hormonogenesis. In support of this hypothesis, several recent reports have shown the presence of elevated molecular chaperone levels in the WIC-rdw thyrocytes, the endoplasmic reticulum of which was markedly dilated, suggesting a defect in intracellular protein transport. Here the studies were undertaken to identify the precise molecular defect in the WIC-rdw rat. First, the genetic linkage analysis revealed that the rdw locus was on rat chromosome 7 and was identical to the thyroglobulin (Tg) gene locus. Moreover, the Tg protein level was reduced in the WIC-rdw thyroid despite a similar level of the Tg gene transcripts that were indistinguishable in their size from the normal. Next, the complete sequencing of the rdw and the normal rat Tg cDNAs revealed a single nucleotide change, G6958C, resulting in a G2320R missense mutation in a highly conserved region of the Tg molecule. Finally, transient expression of the intact Tg cDNA containing the rdw mutation in the COS-7 cells showed no detectable Tg in the secreted media, indicating a severe defect in the export of the mutant Tg. Together, our observations suggest that a missense mutation, G2320R, in the Tg gene is responsible for the rdw mutation in the WIC-rdw rat.

Parallel plate model for trabecular bone exhibits volume fraction-dependent bias

Unbiased stereological methods were used in conjunction with microcomputed tomographic (micro-CT) scans of human and animal bone to investigate errors created when the parallel plate model was used to calculate morphometric parameters. Bone samples were obtained from the human proximal tibia, canine distal femur, rat tail, and pig spine and scanned in a micro-CT scanner. Trabecular thickness, trabecular spacing, and trabecular number were calculated using the parallel plate model. Direct thickness, and spacing and connectivity density were calculated using unbiased three-dimensional methods. Both thickness and spacing calculated using the plate model were well correlated to the direct three-dimensional measures (r(2) = 0. 77-0.92). The correlation between trabecular number and connectivity density varied greatly (r(2) = 0.41-0.94). Whereas trabecular thickness was consistently underestimated using the plate model, trabecular spacing was underestimated at low volume fractions and overestimated at high volume fractions. Use of the plate model resulted in a volume-dependent bias in measures of thickness and spacing (p < 0.001). This was a result of the fact that samples of low volume fraction were much more "rod-like" than those of the higher volume fraction. Our findings indicate that the plate model provides biased results, especially when populations with different volume fractions are compared. Therefore, we recommend direct thickness measures when three-dimensional data sets are available.

Pilocytic astrocytomas do not show most of the genetic changes commonly seen in diffuse astrocytomas

AIMS

While it is well known that pilocytic astrocytomas are clinically distinct from diffuse astrocytomas, few comprehensive studies have focused on their genetic differences. The aim of this study was to examine pilocytic astrocytomas for genetic alterations that are commonly seen in diffuse astrocytomas.

METHODS AND RESULTS

By using molecular genetic and immunohistochemical techniques, we evaluated p16, p53, CDK4 and PTEN genes in 29 pilocytic astrocytomas. Mutation screening of p53 and PTEN was performed by single strand conformation polymorphism analysis followed by direct sequencing. Loss of heterozygosity (LOH) of p53, p16 and 10q23-25 loci was performed with microsatellite markers and genomic microsatellite instability (MSI) was also screened. Protein expression of p16, p53, CDK4 and PTEN was examined by immunohistochemistry. Five tumours were found to have single genetic alterations, which included a p53 mutation, a PTEN mutation, MSI at a single microsatellite marker of the p16 locus, and one single LOH at each p16 and 10q23 loci. Protein expressions of p16, CDK4 and PTEN were detected in 73%, 61% and 38% of tumours, respectively. Significantly and in sharp contrast to diffuse astrocytomas, no pilocytic astrocytoma in our series stained for p53 protein.

CONCLUSION

Pilocytic astrocytomas have neither MSI phenotype nor recurrent alterations of the p53 and p116 genes. However, altered expression of PTEN may be important in the genesis of pilocytic astrocytomas. We conclude that pilocytic astrocytomas are genetically distinct from diffuse astrocytomas. Lack of p53 mutation/immunostaining may serve as a diagnostic adjunct for differentiating pilocytic astrocytomas from diffuse astrocytomas in small neurosurgical biopsies.

Vanadate induces p53 transactivation through hydrogen peroxide and causes apoptosis

Vanadium is a metal widely distributed in the environment. Although vanadate-containing compounds exert potent toxic effects on a wide variety of biological systems, the mechanisms controlling vanadate-induced adverse effects remain to be elucidated. The present study investigated the vanadate-induced p53 activation and involvement of reactive oxygen species (ROS) in p53 activation as well as the role of p53 in apoptosis induction by vanadate. Exposure of mouse epidermal JB6 cells to vanadate led to transactivation of p53 activity in a time- and dose-dependent manner. It also caused mitochondrial damage, apoptosis, and generated ROS. Scavenging of vanadate-induced H(2)O(2) by N-acetyl-l-cysteine (a general antioxidant) or catalase (a specific H(2)O(2) inhibitor), or the chelation of vanadate by deferoxamine, resulted in inhibition of p53 activation and cell mitochondrial damage. In contract, an increase in H(2)O(2) generation in response to superoxide dismutase or NADPH enhanced these effects caused by vanadate. Furthermore, vanadate-induced apoptosis occurred in cells expressing wild-type p53 (p53+/+) but was very weak in p53-deficient (p53-/-) cells. These results demonstrate that vanadate induces p53 activation mainly through H(2)O(2) generation, and this activation is required for vanadate-induced apoptosis.

Activation of AP-1 through the MAP kinase pathway: a potential mechanism of the carcinogenic effect of arenediazonium ions

Arenediazonium ions such as those found in the common mushroom Agaricus bisporus have been convincingly demonstrated to be tumorigenic. The specific mechanism of their tumorigenicity remains unclear. It has been shown that arenediazonium ions can be metabolized to aryl radicals, and that reaction of these aryl radicals with DNA produces aryl adducts. These metabolic processes also produce the reactive oxygen species superoxide and hydroxyl radicals which have been implicated in AP-1 activation. To further investigate the mechanism of tumorigenesis by arenediazonium ions, we studied the effect of a representative arenediazonium ion on AP-1 activation and phosphorylation of the signal transduction proteins ERK1, ERK2, JNK, and p38 kinase, both in vitro and in vivo. We also identified the specific radicals produced by spin trapping and ESR analysis. Here, it was found that p-methylbenzenediazonium ion (2a) induced a 16-fold increase in the extent of AP-1 activation at micromolar concentrations, and that this increase coincided with phosphorylation of the signaling kinases ERK1 and -2 and p38 kinase, but not JNK, in JB6 mouse epithelial cells. In vivo studies using AP-1 luciferase reporter-bearing transgenic mice supported the increase in the extent of AP-1 activation in 2a-treated mice over controls, and showed that this effect was different in different tissue types. The antioxidant N-acetylcysteine (NAC), a general antioxidant, showed an inhibitory effect on 2a-mediated AP-1 induction, while aspirin, a hydroxyl radical scavenger, had no effect. Spin trapping studies showed that while NAC suppressed radical formation from 2a, aspirin did not alter radical production from 2a. It appears that 3a, a carbon-centered radical formed from 2a, is responsible for AP-1-induced activation, and therefore, radical species that are not oxygen-centered are also capable of inducing AP-1. These results represent a step toward understanding the mechanism of tumorigenicity of arenediazonium ions.

High frequency of chromosome 3p deletion in histologically normal nasopharyngeal epithelia from southern Chinese

We have examined the presence of loss of heterozygosity (LOH) on chromosome 3p in histologically normal nasopharyngeal epithelia (NP), dysplastic lesions, and carcinoma of the nasopharynx from different ethnic and geographic regions. Microdissected normal NP from noncancerous individuals and nasopharyngeal carcinoma (NPC) samples from both the high-risk group (southern Chinese in Hong Kong) and two low-risk groups for NPC (central/northern Chinese in Anhui/Beijing and Caucasians in Toronto) were included. All NPC samples showed high incidence of 3p deletion (81-100%). High frequencies of LOH on 3p were also detected in normal NP (73.9%) and dysplastic lesions (75%) from the southern Chinese. Significant lower frequency of LOH on 3p was noted in normal NP from the low-risk groups (20%) than those from high-risk groups (P = 0.0003). The presence of such genetic alterations in the histologically normal NP and dysplastic lesions suggests that it is an early event in tumor development. The higher frequency of 3p LOH found in normal NP from southern Chinese compared with those from low-risk groups may be related to the distinct cancer incidence among these populations.

Participation of MAP kinase p38 and IkappaB kinase in chromium (VI)-induced NF-kappaB and AP-1 activation

Epidemiological studies demonstrate that environmental and occupational exposure of chromium(VI) [Cr(VI)] or Cr(VI)-containing particles can cause a number of human diseases, including inflammation and cancer. The biological mechanisms responsible for the initiation and progression of diseases resulting from exposure to Cr(VI) are not fully understood. The present studies evaluated the ability of Cr(IV) to induce activation of NF-kappaB and AP-1, two important transcription factors governing the expression of many early response genes involved in inflammation and carcinogenesis. The activation of NF-kappaB and AP-1 by Cr(IV) was dose dependent. Aspirin, a well-established antioxidant, substantially inhibited Cr(VI)-induced activation of both NF-kappaB and AP-1. SB202190, a specific inhibitor for p38, attenuated AP-1 activation induced by Cr(IV), whereas PD98059, a specific inhibitor for Erk, exhibited no effect on Cr(IV)-induced AP-1 activation. Blockage of NF-kappaB signaling pathway by a transient transfection of a dominant negative expressing vector for IkappaB kinase beta resulted in inhibition of Cr(IV)-induced NF-kappaB, but not AP-1 activation. These data suggest that the activation of AP-1 or NF-kappaB by Cr(IV) is through the involvement of MAP kinase or IKK pathway, respectively.

Activation of PKC is required for arsenite-induced signal transduction

Trivalent arsenic (arsenite) is a human carcinogen. However, the molecular mechanism of arsenite-induced carcinogenesis is still not well understood. In this study, we found that arsenite induced translocation of PKCepsilon, PKCdelta, and PKCalpha from cytosol to membranes. Rottlerin, a selective inhibitor for PKCdelta, and safingol, a specific inhibitor for PKCalpha, both markedly inhibited arsenite-induced AP-1 activity. These inhibitory effects by rottlerin and safingol appeared to be dose dependent. Arsenite-induced phosphorylation of Erks was inhibited by rottlerin, while safingol inhibited arsenite-induced phosphorylation of JNKs and p38 kinases. Dominant negative mutant transfectant of PKCepsilon markedly blocked arsenite-induced AP-1 activity and the phosphorylation of Erks, JNKs, and p38 kinases. These data demonstrate that PKCdelta, PKCepsilon, and PKCalpha mediate arsenite-induced AP-1 activation in JB6 cells through different MAP kinase (Erks, JNKs, and p38 kinases) pathways.

Causal influences in primate cerebral cortex during visual pattern discrimination

Anatomical studies of the visual cortex demonstrate the existence of feedforward, feedback and lateral pathways among multiple cortical areas. Yet relatively little evidence has previously been available to show the causal influences of these areas on one another during visual information processing. We simultaneously recorded event-related local field potentials (LFPs) from surface-to-depth bipolar electrodes at six sites in the ventral region of the right hemisphere visual cortex in a highly trained macaque monkey during performance of a visual pattern discrimination task. Applying a new statistical measure, the short-time directed transfer function (STDTF), to the LFP data set, we charted the changing strength and direction of causal influence between these cortical sites on a fraction-of-a-second time scale. We present results showing, for the first time, the dynamics of distinct feedforward, feedback and lateral influences in the ventral portion of the primate visual cortex during visual pattern processing.

The role of hydroxyl radical as a messenger in Cr(VI)-induced p53 activation

The present study investigates whether reactive oxygen species (ROS) are involved in p53 activation, and if they are, which species is responsible for the activation. Our hypothesis is that hydroxyl radical (.OH) functions as a messenger for the activation of this tumor suppressor protein. Human lung epithelial cells (A549) were used to test this hypothesis. Cr(VI) was employed as the source of ROS due to its ability to generate a whole spectrum of ROS inside the cell. Cr(VI) is able to activate p53 by increasing the protein levels and enhancing both the DNA binding activity and transactivation ability of the protein. Increased cellular levels of superoxide radicals (O(2)(-).), hydrogen peroxide (H(2)O(2)), and.OH radicals were detected on the addition of Cr(VI) to the cells. Superoxide dismutase, by enhancing the production of H(2)O(2) from O(2)(-). radicals, increased p53 activity. Catalase, an H(2)O(2) scavenger, eliminated.OH radical generation and inhibited p53 activation. Sodium formate and aspirin,.OH radical scavengers, also suppressed p53 activation. Deferoxamine, a metal chelator, inhibited p53 activation by chelating Cr(V) to make it incapable of generating radicals from H(2)O(2). NADPH, which accelerated the one-electron reduction of Cr(VI) to Cr(V) and increased.OH radical generation, dramatically enhanced p53 activation. Thus.OH radical generated from Cr(VI) reduction in A549 cells is responsible for Cr(VI)-induced p53 activation.

Predisposing factors in occupational lung cancer: inorganic minerals and chromium

Reactive oxygen species (ROS) have been implicated in the pathogenesis of cancer. Inhalation of inorganic minerals such as asbestos and crystalline silica, and metals such as arsenic, beryllium, chromium, nickel, and vanadium, may promote directly and indirectly enhanced generation of ROS at a persistent level in concert with chronic inflammation. Perpetual ROS generation can cause specific molecular changes resulting in the activation or inactivation of transcription factors that may alter gene expression leading to cell proliferation, differentiation, and carcinogenesis. The mechanisms involved in the signal transduction leading to these processes are the subject of intense investigation. In this review, some of the recent findings from our laboratories concerning key molecular events elicited by asbestos, crystalline silica, and chromium are presented. These include genotoxicity, DNA damage, lipid peroxidation, activation of transcription factors activator protein-1 (AP-1) or nuclear factor kappa B (NF-kappaB), and p53 or k-ras gene alterations. From these studies, it is evident that ROS signaling is critical for the responses of cytokines, growth factors, and activation or inactivation of transcription factors that promote carcinogenesis.

[Isolation and verification of Triticum aestivum-Eremopyrum orientale addition lines and substitution lines by GISH]

Eremopyrum is a potential genus in wheat improvement. To breed T. aestivum-Er. orientale additional and substitutional lines, chromosome number of 96 BC2F3 individuals were accounted. Fifteen plants with 2n = 43 and eight plants with 2n = 44 were checked out. GISH results of the individuals with 43 chromosomes showed that they blonged to three different monosomic additions. Two disomic additions, one double-monosomic addition, one trible-monosomic addition and one monosomic addition were found in the 2n = 44 individuals. One double-monosomic substitution and one monosomic substitution were obtained. We also proved that it is relatively easier to obtain addition lines in the selfing population than to obtain double-monosomic additions.

First determination of generalized polarizabilities of the proton by a virtual compton scattering experiment

Absolute differential cross sections for the reaction ep-->epgamma have been measured at a four-momentum transfer with virtuality Q2 = 0.33 GeV2 and polarization epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum of the outgoing photon in the photon-proton center of mass frame. The experiment has been performed with the high-resolution spectrometers at the Mainz Microtron MAMI. From the photon angular distributions, two structure functions which are a linear combination of the generalized polarizabilities have been determined for the first time.

Human immunodeficiency virus type 1 shedding pattern in semen correlates with the compartmentalization of viral Quasi species between blood and semen

High levels of human immunodeficiency virus (HIV) type 1 have been detected in semen at all stages of disease. However, it is not clear whether HIV-1 is shed in semen continuously or intermittently. In a prospective longitudinal study, viral RNA was measured weekly for 10 weeks in semen and blood of HIV-seropositive subjects. Results showed three different patterns of HIV-1 shedding in semen: none (28%), continuous (28%), and intermittent (44%). In contrast, there was no change in blood plasma virus load during the study period. Phylogenetic analysis of the envelope sequences of HIV-1 RNA in semen and blood revealed distinct virus populations in semen and blood of intermittent shedders but similar virus populations in the semen and blood of continuous shedder. These results indicate for the first time that HIV-1 is shed primarily in an intermittent manner and that shedding patterns of HIV-1 in semen are related to compartmentalization of HIV-1 between semen and blood.

Anomalous diffusion and the first passage time problem

We study the distribution of the first passage time (FPT) in Levy type anomalous diffusion. Using the recently formulated fractional Fokker-Planck equation we obtain three results. (1) We derive an explicit expression for the FPT distribution in terms of Fox or H functions when the diffusion has zero drift. (2) For the nonzero drift case we obtain an analytical expression for the Laplace transform of the FPT distribution. (3) We express the FPT distribution in terms of a power series for the case of two absorbing barriers. The known results for ordinary diffusion (Brownian motion) are obtained as special cases of our more general results.

Arsenic mediates cell proliferation and gene expression in the bladder epithelium: association with activating protein-1 transactivation

Although the mechanism of action has not yet been defined, epidemiological studies have demonstrated an association between elevated arsenic levels in drinking water and the incidence of urinary bladder transitional cell carcinomas. In the current studies, we demonstrate that mice exposed to 0.01% sodium arsenite in drinking water develop hyperplasia of the bladder urothelium within 4 weeks of exposure. This was accompanied by the accumulation of inorganic trivalent arsenic, and to a lesser extent dimethylarsinic acid, in bladder tissue, as well as a persistent increase in DNA binding of the activating protein (AP)-1 transcription factor. AP-1 transactivation by arsenic also occurred in bladders of transgenic mice containing an AP-1 luciferase reporter. Consistent with these in vivo observations, arsenite increased cell proliferation and AP-1 DNA binding in a human bladder epithelial cell line. Gene expression studies using RNase protection assays, reverse transcription-PCR, and cDNA microarrays indicated that arsenite alters the expression of a number of genes associated with cell growth, such as c-fos, c-jun, and EGR-1, as well as cell arrest, such as GADD153 and GADD45. The proliferation-enhancing effect of arsenic on uroepithelial cells likely contributes to its ability to cause cancer.

Short-window spectral analysis of cortical event-related potentials by adaptive multivariate autoregressive modeling: data preprocessing, model validation, and variability assessment

In this article we consider the application of parametric spectral analysis to multichannel event-related potentials (ERPs) during cognitive experiments. We show that with proper data preprocessing, Adaptive MultiVariate AutoRegressive (AMVAR) modeling is an effective technique for dealing with nonstationary ERP time series. We propose a bootstrap procedure to assess the variability in the estimated spectral quantities. Finally, we apply AMVAR spectral analysis to a visuomotor integration task, revealing rapidly changing cortical dynamics during different stages of task processing.

Toxoplasma gondii catalase: are there peroxisomes in toxoplasma?

The intracellular protozoan parasite Toxoplasma gondii, like all members of the phylum Apicomplexa, is known to possess many organelles: in addition to mitochondria and the compartments of the secretory pathway, there is a reduced chloroplast (the apicoplast) and the phylum-specific components of the apical complex: dense granules, micronemes and rhoptries. Conspicuously missing so far are microbodies, organelles that can be found in nearly all eukaryotic organisms. Microbodies show a large variation with regard to their size, number and contents, depending on the organism and cell type. One marker enzyme of this single membrane-bound organelle is catalase, which is responsible for the degradation of hydrogen peroxide to water and oxygen. The EST project in T. gondii revealed the existence of two overlapping clones which showed similarity with catalase, and these were used to clone the corresponding gene. The predicted sequence of T. gondii catalase has -AKM at the C terminus, which falls within the consensus of the PTS1 peroxisomal targeting signal. Southern blot analysis confirmed the presence of a single copy gene. Northern and western blot analyses showed that the catalase gene is transcribed and translated. Immunofluorescence assays using an antibody raised against a catalase peptide identified a distinct structure towards the apical end, but other catalase-specific antibodies failed to confirm this localisation. Cell fractionations indicated that the majority of the enzyme was in the cytosol. The fusion of the C-terminal twelve amino acids, including AKM, or the canonical peroxisomal targeting signal, -SKL, to GFP resulted in predominantly cytosolic localization in T. gondii. There was therefore no evidence for membrane-bound peroxisomes in Toxoplasma.

Premature structural changes at replication origins in a yeast minichromosome maintenance (MCM) mutant

The Cdc7p protein kinase in the budding yeast Saccharomyces cerevisiae is thought to help trigger DNA replication by modifying one or more of the factors that assemble at replication origins (ARSs). To investigate events catalyzed by Cdc7p, we compared the structure of replication origins in cells containing conditional mutations in Cdc7p and Cdc8p, a thymidylate kinase that is required for DNA synthesis. High resolution genomic footprinting indicated that the presumptive lagging strand template in ARS1 became highly sensitive to KMnO(4) modification after the CDC7 execution point. These results suggested that Cdc7p triggers DNA unwinding. The transition from late G(1) phase to the CDC7 execution point and from the CDC7 to the CDC8 execution points was accompanied by small but ARS-dependent changes in DNA topology. These results suggested that DNA unwinding before the CDC8 execution point either is highly localized or that the torsional stress associated with initial DNA unwinding is minimized by compensatory protein-DNA structural changes. The ARS DNA structural attributes evident in cells blocked at the CDC8 execution point were also evident in alpha-factor-blocked, G(1) phase cells containing the CDC7 bypass mutant mcm5/cdc46-bob1. This result strongly suggests that the structural changes during the transition from the CDC7 to CDC8 execution points depend on the Cdc7p protein kinase and involve alteration of the minichromosome maintenance protein complex.

Age variations in the properties of human tibial trabecular bone and cartilage

Initiated and motivated by clinical and scientific problems such as age-related bone fracture, prosthetic loosening, bone remodeling, and degenerative bone diseases, much significant research on the properties of trabecular bone has been carried out over the last two decades. This work has mainly focused on the central vertebral trabecular bone, while little is known about age-related changes in the properties of human peripheral (tibial) trabecular bone. Knowledge of the properties of peripheral (tibial) trabecular bone is of major importance for the understanding of degenerative diseases such as osteoarthrosis and osteoporosis, and for the design, fixation and durability of total joint prosthesis. The specific aims of the present studies were: 1) to investigate normal age-related variations in the mechanical, physical/compositional, and structural properties of human tibial trabecular bone; and 2) to investigate the age-related and osteoarthrosis-related changes in the mechanical properties of the human tibial cartilage-bone complex; and 3) to evaluate mutual associations among various properties. Normal specimens from human autopsy proximal tibiae were used for investigation of age variations in the properties of trabecular bone and the cartilage-bone complex, and osteoarthrotic specimens were used for the investigation of changes in the mechanical properties of the cartilage-bone complex induced by this disease process. The mechanical properties and physical/compositional properties of trabecular bone were quantified by means of standard techniques, and trabecular bone structure was quantified by means of unbiased three-dimensional methods. The present study demonstrated that the mechanical properties, such as Young's modulus, ultimate stress, ultimate strain and failure energy, and the densities, such as apparent, apparent ash and collagen densities of human tibial trabecular bone have significant relationships with age. Tissue density and mineral concentration remain constant throughout life. Trabecular bone is tougher in the younger age, i.e. fracture requires more energy. Collagen density was the single best predictor of failure energy, and collagen concentration was the only predictor of ultimate strain. The decrease in mechanical properties of trabecular bone mainly is a consequence of the loss of trabecular bone substance. This study showed that the degree of anisotropy (preferential orientation of trabeculae), mean marrow space volume, and bone surface-to-volume ratio increased significantly with age. Bone volume fraction, mean trabecular volume, and bone surface density decreased significantly with age. Connectivity did not have a general relationship with age, yet a trend exists. Age-related changes in the microstructural properties had the same trends for both medial and lateral condyles of the tibia. The observed increase of anisotropy may be interpreted as the consequence of structural adaptation secondary to age-induced bone loss. The aging trabeculae align more strongly to the primary direction, which is parallel to the longitudinal loading axis of the tibia. The mechanical properties of the normal cartilage and bone vary with age and respond simultaneously to mechanical loading. Both cartilage and bone in early-stage OA are mechanically inferior to normal, and OA cartilage and bone have lost their unit function to mechanical loading.

Cell cycle-dependent phosphorylation of centrosomes: localization of phosphopeptide specific antibodies to the centrosome

The microtubule nucleation capacity of the centrosome increases dramatically as cells progress from interphase into mitosis. The increase in nucleation capacity of the centrosome correlates with the cell cycle-dependent localization of the mitotic protein monoclonal-2 (MPM-2) phosphoepitope-specific antibody to the mitotic centrosome. Therefore, the phosphorylation state of centrosomal components may regulate the microtubule nucleation capacity of this organelle during mitosis. Neither the identity of the MPM-2 kinase(s) nor all of the MPM-2-reactive phosphoproteins associated with the centrosome have been fully elucidated. Only recently have the characteristics of the MPM-2 epitope site been defined, and we used this information to prepare polyclonal antibodies against synthetic phosphopeptides containing potential MPM-2 epitopes derived from the sequences of two MPM-2-reactive proteins, topoisomerase II, and microtubule associated protein 1B (MAP1B). We demonstrate that these phosphopeptide-specific antibodies also localize to the centrosome in a cell cycle-dependent fashion. Thus, polyclonal antibodies have been generated against defined phosphopeptides that reiterate many of the immunofluorescence staining properties exhibited by the MPM-2 antibody. These new phosphopeptide-specific antibodies will provide additional probes to examine the phosphorylation of centrosomal components and the functional consequences of their phosphorylation during mitosis.

[Study on the morphological processing of classical swine fever virus in cultured cells]

An infected mode between the Thiverval strain and Chinese strain of CSFV and MPK cells are established. The morphological structure and processing of different strains(T strain, C strain and F strain) of CSFV were studied by ultra-thin section electron microscopy. The virions of CSFV are roughly round and approximately 70 nm in diameter with a 40 nm core, and are wraped by membrane. The distinctive pathway of the maturation and release of CSFV are observed. Virons on different deverloping state and the pathologic changes of host cells have also been reported in this paper.

[Molecular cloning and expression of E2 gene of the Chinese classical swine fever virus(shimen strain) and preliminary studies of its DNA vaccine]

A 1.1 bp fragment of E2 gene of Chinese classical swine fever virus(CSFV) Shimen strain, a standard virulent strain, was amplified by RT-PCR from total RNA of cell cultures infected by CSFV, and cloned into pGEM T vector. The nucleotide sequence of this fragment was sequenced by Sanger's method and the amino acid sequence was deduced. Compared with the corresponding region of Alfort, Brescia and C strain of CSFV, the nucleotide sequence homology is 84.7%, 92.6% and 95.2% respectively, and the amino acid sequence 89.4%, 92.6% and 94.6%, respectively, we subcloned 1.1 bp of E2 gene cDNA into baculovirus transfer vector and successfully constructed two recombinant baculoviruses expressing GST-E2 and GST-GFP-E2 fusion protein respectively by homologous recombination in sf-9 cell. Furthermore, we also constructed recombinant eukaryotic expression vector pcE2 containing E2 gene in frame and transfected COS-7 cell by lipofectamine, the indirect immunofluorescence assay (IFA) showed that the expressed E2 protein can be recognized by E2 specific monoclonal antibody the pcE2 DNA was directly injected into BALB/c mice intramuscular(i.m.) and the CSFV E2-specific antibodies was measured by enzyme-linked immunosorbent assay(ELISA) the ELISA results indicated the E2-specific antibodies was induced in inoculated mice and virus neutralization assays also indicate single inoculations of plasmids expressing CSFV E2 glycoprotein raised neutralizing antibody in BALB/c mice. these results will be beneficial to investigate the possibility of DNA vaccine against CSFV.

Analysis of tetramethylpyrazine in Ephedrae herba by gas chromatography-mass spectrometry and high-performance liquid chromatography

A simple and reliable HPLC method was developed for the determination of 2,3,5,6-tetramethylpyrazine (TMP) in Ephedrae herba. Further identification of TMP was achieved using GC-MS. The mobile phase used was methanol-water-35% acetic acid (35:65:0.5, v/v/v) at a flow-rate of 0.8 ml/min. The detection wavelength was set at 290 nm. The linear range of the peak area calibration curve of TMP was 2.64-264 mg/l (r=0.9987) and the recovery for TMP in Ephedrae herba extracts was 101.1-106.9%. The relative standard deviations of retention time and peak area were 0.18 and 1.5% (n=6), respectively. The detection limit of TMP was 0.03 mg/l. The contents of TMP in Ephedrae herba could easily be determined within 10 min.