First Report on the Occurrence of A2 Mating Type of the Cucurbit Downy Mildew Agent Pseudoperonospora cubensis in China

Pseudoperonospora cubensis is a foliar pathogen of cucurbits. In cucumber, it produces chlorotic, angular lesions with dark sporangia on their under-surface. The distribution of pathotypes and mating types of P. cubensis were investigated in seven provinces in China. Twenty-nine isolates were obtained from Guangdong, Anhui, Hubei, Sichuan, Shandong, Beijing, and Harbin, one to six isolates from each province. They were collected from cucumber during summer 2011, except those from Harbin, which were collected from cucumber in summer 2012. Isolates were tested for pathogenicity and mating type. Pathogenicity was tested by inoculation of detached leaves of: cucumber (Cucumis sativum cvs. Bet-Alpha, SMR18), melon (Cucumis melo reticulatus cv. Ananas-Yokneam), pumpkin (Cucurbita maxima cv. Tripoli), squash (Cucurbita pepo, cv. Beruti), butternut gourd (Cucurbita moschata cv. Waltham), watermelon (Citrullus lanatus, cv. Malali), and sponge gourd (Luffa cylindrica, cultivar unknown). Mating type was determined by oospore production in melon leaf discs inoculated with mixed sporangia of a test isolate and A1 or A2 tester isolates, as recently described (2). The results showed that 22 isolates belonged to pathotype 3, sporulating on cucumber and melon; five isolates belonged to pathotype 6, sporulating on cucumber, melon, pumpkin, squash, and butternut gourd; one isolate belonged to pathotype 5, sporulating on the above five species and watermelon (1), and one isolate was capable of sporulating on the mentioned five species and sponge gourd, herein called pathotype 7. Of the 29 isolates tested, 22 belonged to the A1 mating type, six to the A2 mating type, and one did not produce oospores with either testers. Of the six A2 isolates, two originated from Sichuan, one from Beijing, and three from Harbin. All 22 isolates belonging to pathotype 3 were A1, whereas the other six isolates (four pathotype 6, one pathotype 5, and one pathotype 7) were A2. Crosses made between Chinese isolates belonging to opposite mating types resulted in the formation of abundant oospores in detached melon or cucumber leaves. The results prove that the A2 mating type of P. cubensis occurs in China. This explains the abundant occurrence of oospores of P. cubensis in nature in China (4). The data corroborate with Runge et al. (3), who suggested that the recent changes in the population structure of P. cubensis around the world resulted from the migration of a new genotype of P. cubensis from the Far East to Europe and the U.S.A. In Israel, a new pathotype attacking both Cucumis and Cucurbita appeared in 2002 (1), and A2 mating type first appeared in 2010 (2). References: (1) Y. Cohen et al. Phytoparasitica 31:458, 2003. (2) Y. Cohen and A. E. Rubin. Eur. J. Plant Pathol. 132:577, 2012. (3) F. Runge et al. Eur. J. Plant Pathol. 129:135, 2011. (4) Y. J. Zhang et al. J. Phytopathol. 160:469, 2012.

First Report of Hosta virus X Infecting Hosta Plants in China

Hosta (Hosta spp.) plants showing leaf deformation, puckering, and ink-bleed symptoms were collected in July 2012 from a park at Dongcheng district, Beijing, China. Three out of six samples tested positive for Hosta virus X (HVX) by immunostrip and double-antibody sandwich (DAS)-ELISA with HVX-specific serological reagents from Agdia Inc. (Elkhart, IN, USA). Filamentous viral particles were trapped and observed from the infected hosta leaf sap by immuno-serological electron microscopy (ISEM) (antibodies from Agdia). To confirm HVX infection, three ELISA-positive samples were analyzed by reverse transcription-PCR assay, using virus-specific primers HVXf (5'-ATCCGTTATCTACAGGGGACCAG-3') and HVXr (5'-TAAGTTAGTGGAACGGTTAGCCCGAT-3') that amplified a 1,067-bp fragment including the coat protein (CP) coding region. The CP nucleotide sequence comparisons showed 99% to 100% homology among the three isolates named HVXBJ4, HVXBJ5, and HVXBJ6 (GenBank Accession No. JX535292, JX535293, and JX535294) and with the HVX sequences previously reported in GenBank. HVX has been reported from the United States, Korea, the Netherlands, Poland, France, the Czech Republic, and New Zealand (1,2). To our knowledge, this is the first report of HVX infecting hosta plants in China. As an ornamental and medicinal plant, hosta has been cultivated in China for more than 2,000 years. The presence of HVX in Beijing is a potential threat to the landscape in the city. HVX can be spread by vegetative propagation material or mechanical contact (3). Hence, to cultivate HVX-free hosta and restrict the movement of HVX-infected hosta is vitally important in the future. HVX has become economically important in the world more recently. Globalization of trade in hosta plants has increased the risk of movement of HVX. The national plant protection organization should establish effective quarantine strategy and the growers take proper planting measures to avoid further spreading of this virus. References: (1) S. Currier et al. Plant Dis. 80:1040, 1996. (2) M. H. Park et al. Arch. Virol. 148:2039, 2003. (3) K. H. Ryu et al. Acta Hortic. 722:91, 2006.

Association between CASP-8 gene polymorphisms and cancer risk in some Asian population based on a HuGE review and meta-analysis

Genetic variation in the CASP-8 gene reportedly can increase cancer susceptibility by regulating tumor cell proliferation and apoptosis. Several studies have investigated this possibility; however, the conclusions remain controversial. We made a Human Genome Epidemiology (HuGE) review and did a meta-analysis to explore the association between CASP-8 gene polymorphisms and cancer risk in Asian populations. Based on the inclusion criteria, 12 case-control studies comprising 7720 cancer cases and 9404 healthy controls were retrieved. Meta-analysis results showed that the rs3834129*del allele/carrier were associated with decreased risk of cancer in Asian populations [del allele: odd ratio (OR) = 0.79, 95% confidence interval (95%CI) = 0.75-0.83, P < 0.001; del carrier: OR = 0.77, 95%CI = 0.72-0.82, P < 0.001]. Subgroup analysis showed that the rs3834129*del allele/carrier are protective factors for cancer risk in Chinese populations (del allele: OR = 0.77, 95%CI = 0.73-0.81, P < 0.001; del carrier: OR = 0.75, 95%CI = 0.70-0.80, P < 0.001), but not in Indian and Korean populations. Furthermore, the rs6704688*T allele/carrier, rs3769827*C allele/carrier, rs3769825*C allele/carrier were associated with decreased risk of cancer in Asian populations (all P < 0.05). While the rs7608692*A allele was associated with increased risk of cancer risk in Asian populations (OR = 1.35, 95%CI = 1.02-1.78, P = 0.03). There was also no significant association between rs3769818, rs13030042, rs13030042, rs1045494, rs1045494, rs2823, or rs113686495, and cancer risk in Asian populations (all P > 0.05). This meta-analysis suggests that the rs3834129*del allele/ carrier, rs6704688*T allele/carrier, rs3769827*C allele/carrier, and rs3769825*C allele/carrier might be protective factors for cancer risk in Asian populations, while the rs7608692*A allele might be a risk factor for cancer risk in Asian populations.

Efficient isolation of high-quality RNA from lotus Nelumbo nucifera ssp nucifera tissues

Nelumbo nucifera is widely used as food, as an ornamental, in medicine, and as packing material; it is also reported to have anti-HIV effects and antioxidant capacity. We sought an improved method for extracting high-quality total RNA from different tissues of N. nucifera. Four methods for RNA extraction were assessed for their ability to recover high-quality RNA applicable for evaluation of polyphenol oxidase (PPO) gene expression profiles. The recovery and quality of the RNA obtained from five different tissues by the best CTAB-LiCl method were evaluated through UV light absorbance. Both A(260)/A(280) and A(260)/A(230) absorbance ratios were more than 2.0; the yield ranged from 59.87 to 163.75 μg/g fresh weight. The brightness of the 28S band was approximately twice that of 18S; the latter was also considered as high-quality RNA. The PPO gene fragment (606 bp) was successfully amplified by RT-PCR, demonstrating the integrity of the isolated RNA. The relative expression levels of the PPO gene based on RT-PCR in five tissues of lotus were: rhizome buds (2.66), young leaves (2.42), fresh cut rhizome (2.02), petals (1.80), and petiole (1.65), using housekeeping gene β-actin as an internal control. We concluded that the total RNA isolated by this protocol is of sufficient quality for molecular applications.

The protective effect of curcumin on Aβ induced aberrant cell cycle reentry on primary cultured rat cortical neurons

OBJECTIVES

Alzheimer's disease (AD) is a neurodegenerative disorder marked by progressive loss of memory and impairment of cognitive ability. One current hypothesis for AD pathogenesis is that neuronal death is linked to aberrant cell-cycle re-entry. In AD, neurons have been shown to enter the cell cycle inappropriately without the ability to complete it fully and the aberrant re-entry leads to its death. Curcumin has been reported as having a neural protective effect on the AD model, and could modulate the proliferation of tumor cells through the regulation of cyclin D1 and c-myc cell signaling pathways. In this study, we first observed the protective action of curcumin on Abeta-induced neuron damage, and then investigated whether this protective effect was a result of the inhibition of cell cycle advance.

MATERIALS AND METHODS

We used MTT assay and TUNEL assay to observe the effect of curcumin on Abeta-induced neuron death, and then examined the activated caspase-3 protein level to further confirm the protective effect of curcumin against Abeta-induced neuron toxicity. Next, we further investigate whether the inhibition of cell cycle reentry was mediated by the therapeutic effect of curcumin on Abeta induced primary cultured neuron damage by Brdu label assay and western blot assay.

RESULTS

The results showed that administration of curcumin (1-10 microM) could inhibit Abeta25-35 (40 microg/ml) induced primary cultured rat cortical neuron death, down-regulating activated caspase-3 protein expression. Furthermore, treatment with curcumin could inhibit abnormal activated cyclin D1 protein level, and decrease the Brdu positive cells in proportion to the Abeta25-35 treatment neurons.

CONCLUSIONS

All the results suggest that curcumin has a protective effect against Abeta-induced toxicity in cultured rat cortical neurons, the inhibition of cell cycle re-entry at least partly mediating the therapeutic effect of curcumin in the AD model in vitro.

Inhibition of primary effusion lymphoma engraftment in SCID mice by morpholino oligomers against early lytic genes of Kaposi's sarcoma-associated herpesvirus

BACKGROUND

Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with several malignant diseases, including Kaposi's sarcoma, primary effusion lymphoma (PEL) and multicentric Castleman's disease. The objectives of this study were to investigate the use of peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) against KSHV early lytic genes and to assess their efficacy in severe combined immunodeficiency disease (SCID) mice against PEL engraftment. PPMOs are short, single-stranded DNA analogues that contain a backbone of morpholine rings and phosphorodiamidate linkages and have high delivery efficiency into cells.

METHODS

PEL cells were treated with PPMOs against viral interferon regulatory factor 1 (vIRF-1) and expression of vIRF-1 was analysed. PPMOs against vIRF-1 and viral interleukin-6 (vIL-6) were evaluated against PEL cell engraftment in SCID mice. The PPMOs were incubated with BCBL-1 cells and then introduced into the peritoneal cavities of SCID mice, followed by 9 more doses of PPMOs administered at 2-day intervals. At weeks 3 and 9 after BCBL-1 delivery, peritoneal lavage was collected and the ratio of PEL cells among total cells was determined by flow cytometry analysis.

RESULTS

Treatment of PEL cells with PPMOs against vIRF-1 led to a reduction of vIRF-1 expression in a dose-dependent manner. Reduction of vIRF-1 expression resulted in higher levels of cellular interferon regulatory factor 3 and of signal transducer and activator of transcription 1. SCID mice receiving a PPMO against vIL-6 had no engraftment of PEL cells and remained healthy throughout the 120-day study.

CONCLUSIONS

This study showed that PPMOs can be effective antiviral agents against KSHV. Blocking the expression of early lytic genes might be beneficial for the control of KSHV-associated malignant diseases.

Contributions of heme oxygenase-1 in postconditioning-protected ischemia-reperfusion injury in rat liver transplantation

BACKGROUND

Heme oxygenase-1 (HO-1), an oxidative stress-response gene up-regulated by various physiological and exogenous stimuli, has cytoprotective activities. Ischemic postconditioning (Postcon) can protect an organ from ischemia-reperfusion (I/R) injury. In the present study, we investigated the potential contributions of HO-1 to Postcon-dependent protection against I/R injury in rat liver transplantation models.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were randomly divided into four groups: sham group with laparotomy for liver exposure; I/R group with 24-hour cold ischemia of the donor liver; Postcon group with the same treatment as the I/R group plus ischemic Postcon; and zinc protoporphyrin (ZnPP HO-1 inhibitor) + Postcon group treated the same as the Postcon cohort with donors pretreated using ZnPP 24 hours before the I/R injury. We measured liver tissue and peripheral blood samples collected at 6 hours after reperfusion and serum transaminase levels, histopathology, liver tissue malondialdehyde (MDA) content, superoxide dismutase (SOD) activity and HO-1 expression in the liver.

RESULTS

Postcon significantly diminished the elevation of serum transaminases levels after I/R injury when compared with I/R and ZnPP+Postcon groups. Postcon treated rats showed significantly lower MDA production and higher SOD activity. HO-1 was induced in rat livers exposed to Postcon; its levels were obviously overexpressed after 6 hours in Postcon rats. Inhibiting the expression of HO-1, negated the protective effects of Postcon.

CONCLUSIONS

Induction of HO-1 in the Postcon condition played a protective role against hepatic I/R injury and enhanced the early antioxidative activity. The protective effects of Postcon were significantly associated with greater intrahepatic HO-1 expression.

Investigation of the genetic diversity of an invasive whitefly (Bemisia tabaci) in China using both mitochondrial and nuclear DNA markers

It is often considered that reduced genetic variation due to bottlenecks and founder effects limits the capacity for species to establish in new environments and subsequently spread. The recent invasion (during the past five years) of an alien whitefly, one member of Bemisia tabaci cryptic species complex, referred to as Mediterranean (herein referred to as Q-type) in Shandong Province, China, provides an ideal opportunity to study the changes in genetic variation between its home range in the Mediterranean region and its invasion range. Using both the mitochondrial cytochrome oxidase I (mtCOI) and nuclear (microsatellite) DNA, we show that Q in Shandong likely originated in the western Mediterranean. We also found that the haplotype diversity was low compared with its presumed geographic origin, whereas microsatellite allele diversity showed no such decline. A key factor in invasions is the establishment of females and so bottleneck and founder events can lead to a very rapid and considerable loss of mitochondrial diversity. The lack of haplotype diversity in Shandong supports the interpretation that, at one or more points between the western Mediterranean and China, the invading Q lost haplotype diversity, most probably through the serial process of establishment and redistribution through trade in ornamental plants. However, the loss in haplotype diversity does not necessarily mean that nuclear allelic diversity should also decline. Provided females can mate freely with whichever males are available, allelic diversity can be maintained or even increased relative to the origin of the invader. Our findings may offer some explanation to the apparent paradox between the concept of reduced genetic variation limiting adaptation to new environments and the observed low diversity in successful invaders.

Further insights into the strange role of bacterial endosymbionts in whitefly, Bemisia tabaci: comparison of secondary symbionts from biotypes B and Q in China

The percentage infection of secondary symbionts (SS) (Wolbachia, Arsenophonus, Rickettsia, Hamiltonella, Fritschea and Cardinium) in the exotic Bemisia tabaci (Genn.) invaders, commonly known as biotypes B and Q from China, were determined by PCR. In total, 373 biotype B and 1830 biotype Q individuals were screened for the presence of SS. Biotype B was more abundant than biotype Q from 2005 to 2006, and biotype Q was more abundant from 2007 to 2009. Each of the SS, with the exception of Fritschea, was detected in both biotypes B and Q; Fritschea was found in none of the samples examined. For biotype B, the percentage infection of Hamiltonella was the highest (92.0%) followed by Rickettsia (70.2%). For biotype Q, the percentage infection of Hamiltonella was again the highest (73.3%). Arsenophonus was the least common of the SS observed in both biotypes B and Q. The percentage infection of Wolbachia, Rickettsia and Hamiltonella in biotype B was each significantly higher than in biotype Q, whereas the percentage infection of Cardinium in biotype B was significantly lower than in biotype Q. The percentage infection of SS in biotypes B and Q varied from year to year over the period 2005-2009. Furthermore, within biotype Q, two distinct subgroups were identified which differ from each other in terms of their SS complement. We discuss these results in the light of the potentially influential factors and roles of the SS.

Inhibition of porcine reproductive and respiratory syndrome virus infection in piglets by a peptide-conjugated morpholino oligomer

Porcine reproductive and respiratory syndrome (PRRS) causes substantial economic losses to the swine industry in many countries, and current control strategies are inadequate. Previously, we explored the strategy of using peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) to inhibit PRRS virus (PRRSV) replication. PPMOs are nuclease-resistant and single-stranded DNA analogs containing a modified backbone conjugated to a cell-penetrating peptide and can act as antisense agents through steric blockade of complementary messenger RNA. A PPMO (designated 5UP2) targeting highly conserved sequence in the 5'-terminal region of the PRRSV genome was found to produce multi-log10 inhibition of PRRSV replication in cultured cells. To evaluate 5UP2 in vivo, we here administrated the PPMO to 3-week-old piglets via intranasal instillation at 24h before, and 2 and 24h after infection with PRRSV (strain VR2385). Blood samples were collected at 6, 10 and 14 days post-infection (dpi) for detection of PRRSV RNA and antibodies. Necropsy was performed at 14 dpi. Monitoring weight gain in all piglet groups throughout the experiment indicated that PPMO was well tolerated at the doses used. PPMO 5UP2 treatment significantly reduced PRRSV viremia at 6 dpi. On day 14, piglets receiving 5UP2 had significantly less interstitial pneumonia and lower level of anti-PRRSV antibodies than untreated piglets. In alveolar macrophages isolated at the time of necropsy, the expression of antiviral genes in PPMO-treated piglets was elevated in comparison with untreated. This study provides further data indicating that the 5UP2 PPMO can be considered a candidate component for a novel PRRS control strategy.

Studies on interaction of cucurbit aphid-borne yellow virus proteins using yeast two-hybrid system and bimolecular fluorescence complementation

In this article, yeast two-hybrid system (YTHS) and bimolecular fluorescence complementation (BiFC) were used to analyze the interactions of cucurbit aphid-borne yellows virus (CABYV)-encoded proteins. P0, P1, P1-2, P3, P4, and P5 were tested by YTHS in all possible pairwise combinations, and only P3/P3 interaction was detected. Results obtained by BiFC further confirmed the self-interaction of P3, and the subcellular localization of reconstituted YFP fluorescence was observed mainly in nuclei of Nicotiana benthamiana leaf epidermal cells. Domains involved in P3/P3 self-interaction were analyzed by YTHS and BiFC using deletion mutants. The results showed that R domain (residues 1-61) in the N-terminus could self-interact, and it also interacted with the S domain (residues 62-199) in the C-terminus of P3. The present work would serve as a molecular basis for further characterization of CABYV proteins, and the regions involved in P3/P3 self-interaction could provide the clue for understanding the capsid assembly pathway of CABYV.

A simple method of genomic DNA extraction suitable for analysis of bulk fungal strains

AIMS

A simple and rapid method (designated thermolysis) for extracting genomic DNA from bulk fungal strains was described.

METHODS AND RESULTS

In the thermolysis method, a few mycelia or yeast cells were first rinsed with pure water to remove potential PCR inhibitors and then incubated in a lysis buffer at 85 degrees C to break down cell walls and membranes. This method was used to extract genomic DNA from large numbers of fungal strains (more than 92 species, 35 genera of three phyla) isolated from different sections of natural Ophiocordyceps sinensis specimens. Regions of interest from high as well as single-copy number genes were successfully amplified from the extracted DNA samples. The DNA samples obtained by this method can be stored at -20 degrees C for over 1 year.

CONCLUSIONS

The method was effective, easy and fast and allowed batch DNA extraction from multiple fungal isolates.

SIGNIFICANCE AND IMPACT OF STUDY

Use of the thermolysis method will allow researchers to obtain DNA from fungi quickly for use in molecular assays. This method requires only minute quantities of starting material and is suitable for diverse fungal species.

Morpholino oligomer-mediated protection of porcine pulmonary alveolar macrophages from arterivirus-induced cell death

BACKGROUND

Porcine reproductive and respiratory syndrome (PRRS) causes extensive economic losses in the swine industry. Current strategies and vaccines to control the disease are inadequate. We previously demonstrated that peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) could potently inhibit PRRS virus (PRRSV) replication in cell cultures. PPMOs are single-stranded DNA analogues containing a modified backbone and cell-penetrating peptide. PPMOs are nuclease-resistant, water-soluble, can enter cells readily and exhibit highly specific binding to complementary RNA. In this study, we examined PPMO-mediated inhibition of PRRSV replication in a primary culture of porcine pulmonary alveolar macrophages (PAMs).

METHODS

PAMs were collected from piglets, pre-incubated in culture and infected with PRRSV. Viability, cytopathic effects, virus yield and apoptosis of PAMs in the presence or absence of a PPMO (5UP2) were examined. The 5UP2 PPMO is complementary to a conserved sequence in the 5'-terminal region of the PRRSV genome. The level of several interferon-associated gene products and activity of caspases were monitored.

RESULTS

PRRSV infection induced the activity of caspases-3/7, -8 and -9 significantly. Treatment of PAMs with 5UP2 resulted in protection of the cells from PRRSV-induced cell death for at least 7 days and avoided the activation of the caspases evaluated. 5UP2 treatment of PRRSV-infected PAMs also prevented the vigorous induction of interferon-beta and chemokines observed in infected and mock-treated PAMs.

CONCLUSIONS

PPMO-mediated suppression of PRRSV replication in PAMs was associated with a reduction of apoptotic and inflammatory responses. These results provide further rationale for the development of PPMO 5UP2 as an antiviral to control PRRSV infection.

Performance of PAC/PDM composite coagulants for removal of algae from Lake Taihu waters in summer

The enhanced coagulation of algae-rich raw water from Lake Taihu in summer was studied by use of composite coagulants. The composite coagulants were composed of polyaluminum chloride (PAC) and polydimethyldiallylammonium chloride (PDM) with various intrinsic viscosity values (0.55-3.99 dL/g) and different mass percentages (5-20%) in the formulation. For raw water with temperature of 28-29 degrees C and algae content of 3.60x10(4)-3.70x10(4) cells/ml, the algae-removal rates of 89.0% and 89.3-93.1% could be realized by using PAC and PAC/PDM (0.55/5%-3.99/20%) with dosages of 8.37 mg/L and 5.93-3.58 mg/L, respectively, when 2 NTU residual turbidity of treated water after sedimentation was required. Compared with using PAC only, the removal rate of CODMn using PAC/PDM increased at least 4.4% when the dosage was 8 mg/L, and increased at least 5.0% when the dosage was 10 mg/L. The composite coagulants could still function well when raw water quality deteriorated and algae content reached 8.00x10(4) cells/ml. The enhanced coagulation efficiency of PAC/PDM (0.55/5%) could be better than that of PAC combined with prechlorination process when the same dosages are used.

Association between sexual precocity and alleles of KISS-1 and GPR54 genes in goats

KISS-1 and GPR54 were regarded as key regulators for the puberty onset and fundamental gatekeepers of sexual maturation in mammals. To explore the possible association between variations in KISS-1 and GPR54 with sexual precocity, mutation screening of exon 1 of KISS-1 and exon 1, exon 3, and partial exon 5 of GPR54 was performed in a sexual precocious breed (Jining Grey goats) and sexual late-maturing breeds (Inner Mongolia Cashmere, Angora, and Boer goats) by PCR-SSCP. The results showed that five novel mutations were identified in exon 1 and partial exon 5 of GPR54 including C96 T, T173C, G176A, G825A, and C981 T. The Jining Grey goats with genotype BB or AB had 1.07 (P < 0.05) or 0.40 (P < 0.05) kids more than those with AA. The Jining Grey goats with genotype DD or CD had 1.80 (P < 0.05) or 0.55 (P < 0.05) kids more than CC, respectively. The present study preliminarily showed an association between alleles B and D of GPR54 with high litter size and sexual precocity in Jining Grey goats.

In vitro and in vivo anticancer activity of steroid saponins of Paris polyphylla var. yunnanensis

AIM

To confirm the anticancer activity of steroid saponins isolated from the rhizome of Paris polyphylla var. yunnanensis and evaluate the structure-activity relationships of these steroid saponins in vitro and in vivo .

MATERIALS AND METHODS

Eight known steroid saponins were isolated from the rhizome of Paris polyphylla . The LA795 lung adenocarcinoma cell line from mice was chosen to evaluate cytotoxicity by means of MTT assay, and to study apoptosis by means of AnnexinV-FITC/PI flow cytometry. Diosgenin-3alpha-L-arabinofuranosyl(1-->4)-[alpha-L-rhamnopyranosyl(1-->2)]-beta-D-glycopyranoside (compound 1), the main steroid saponin of Paris polyphylla , and diosgenin (Dio), the aglycone of major steroid saponins, were evaluated for antitumor activity on LA795 lung adenocarcinoma in T739 inbred mice.

RESULTS

The steroid saponins showed remarkable cytotoxicity and caused typical apoptosis in a dose-dependent manner. They were evaluated in vivo by their effect on tumor developed in T739 inbred mice. The oral administration to T739 mice bearing LA795 lung adenocarcinoma of compound 1 and diosgenin significantly inhibited tumor growth, by 29.44% and 33.94%, respectively. HE staining showed that lungs and livers of treated mice underwent various levels of histopathological alterations. It was demonstrated by TUNEL assay that apoptosis rate in tumor cells was increased in comparison to cells in control mice. The 3-O-glycoside moiety and spirostanol structure played an important role in the anticancer activity of steroid saponins, and the number and the variety of glycosides of compounds strongly influenced on their anticancer activity.

CONCLUSION

Rhizoma Paridis saponins showed anticancer activity against lung adenocarcinoma cell line, both in vitro and in vivo, and their effect was dependent on compounds' structure in a certain degree.

Enhanced inhibition of porcine reproductive and respiratory syndrome virus replication by combination of morpholino oligomers

Porcine reproductive and respiratory syndrome (PRRS) has caused heavy economic losses in the swine industry worldwide and current strategies to control PRRS are inadequate. Previous studies have shown that peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) can be an effective antiviral against the PRRS virus (PRRSV). PPMO is structurally similar to DNA with modified backbone and is resistant to nuclease. This study was designed to examine increasing inhibitory effect of PPMO combination. Two pairs of PPMOs were identified to have enhanced suppression of PRRSV replication in cell culture, while individual constituents did not work under the same testing conditions. PPMO 5UP1 that is complementary to 5′ terminus of PRRSV genome was paired with 4P1 or 7P1 that are complementary to sequence in the translation initiation regions of ORFs 4 and 7, respectively. The PPMO combination also inhibited replication of heterologous strains in the North American PRRSV genotype. Treatment of the cells with the combinations reduced PRRSV RNA and protein levels. In cell-free or cell-based luciferase reporter assays, the PPMO combination suppressed target mRNA translation more effectively than individual constituents, indicating that the suppression was due to their antisense effect. These results suggest potential application of these PPMO combinations for PRRS control.

Occurrence of Cucumber green mottle mosaic virus on Cucurbitaceous Plants in China

Cucumber green mottle mosaic virus (CGMMV) was first discovered in 2003 in China (2) and developed an epidemic during 2005 (1). To know the occurrence scale and damage level of CGMMV, a survey was carried out in the main areas of cucurbitaceous plant production and seed trading in 2006 and 2007 in Mainland China. Samples of 739 plants of 16 types (seed samples from Cucurbita moschata, Cucumis melo, Lagenaria siceraria, Cucumis sativus, Momordica charantia, L. siceraria var. clavata, and C. pepo, leaf samples from C. moschata, Cucumis melo, L. siceraria, Cucumis sativus, and M. charantia, fruit samples from C. moschata, Citrullus lanatus, and L. siceraria, and seedling samples from Citrullus lanatus) were collected from 13 regions and analyzed by a double antibody sandwich (DAS)-ELISA. CGMMV was detected in Citrullus lanatus, L. siceraria, Cucumis melo, and C. moschata from six regions in 2006. Citrullus vulgaris, Cucumis melo, and C. moschata were infected most frequently; in 76, 60, and 30 of the leaf samples, respectively. CGMMV was tested positive in the samples of 8 seedlings, 23 seeds, and 1 fruit. In contrast, all samples tested negative in 2007. To confirm CGMMV identification, ELISA-positive samples were detected by reverse transcription-PCR assay using virus-specific primers that amplified a 524-bp fragment in the coat protein coding region. The nucleotide sequence of the PCR product (GenBank Accession No. DQ997778) isolated form L. siceraria in Liaoning Province (LHP) showed 100% identity with the Japanese watermelon strain (Japan W) and 91% identity with the Greece GR5 strain. On the basis of the symptoms of indicator plants (chlorotic spot and systemic mosaic were observed in L. siceraria, Chenopodium amaranticolor, and Cucumis sativus; no infection was observed in Datura stramonium, Nicotiana tabacum, and Chenopodium quinoa) and coat protein nucleotide sequence comparisons, the two CGMMV isolates of Wcn (1) and LHP from China should be grouped into the watermelon strain. The results showed that the government should establish effective quarantine strategy and the growers take proper planting measures to avoid further spreading of this virus. References: (1) H. Y. Chen et al. Acta Phytopathol. Sin. 36:306, 2006. (2) B. X. Qin et al. Plant Quarantine. 19:4, 2005.

Quantification of Fusarium graminearum in harvested grain by real-time polymerase chain reaction to assess efficacies of fungicides on fusarium head blight, deoxynivalenol contamination, and yield of winter wheat

We used a real time polymerase chain reaction-based assay and visual disease assessment to evaluate the efficacies of Js399-19, tebuconazole, a mixture of tebuconazole and thiram, azoxystrobin, carbendazim, and thiram on the development of Fusarium head blight (FHB) and deoxynivalenol (DON) contamination and on the yield of winter wheat (cv. Nannong no. 9918) after artificial inoculation under field conditions with Fusarium graminearum. The incidence of infected spikelets (IIS), amount of F. graminearum DNA (Tri5 DNA), total DON (containing DON, 3-acetyl-deoxynivalenol, and 15-acetyl-deoxynivalenol) concentration, and 1,000-grain weight (TGW) were quantified in 2006 and 2007. A strong positive correlation was found between IIS or Log10Tri5 DNA and total DON concentration in the harvested grain. The Js399-19, tebuconazole, and the mixture of tebuconazole and thiram significantly reduced IIS of FHB, amount of Tri5 DNA, and total DON within the grain and increased TGW. Although azoxystrobin, carbendazim, and thiram can increase TGW, they had no effect on the occurrence of F. graminearum compared with those of the untreated controls. Surprisingly, azoxystrobin and carbendazim significantly increased the total DON content in the harvested grain because they might have stimulated the amount of total DON production per Tri5 DNA. The fungicides Js399-19, tebuconazole, and the mixture of tebuconazole and thiram were the most effective in controlling FHB and reducing DON contamination of the wheat.

Blockade of viral interleukin-6 expression of Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8, is associated with several malignant disorders, including Kaposi's sarcoma, primary effusion lymphoma (PEL), and multicentric Castleman's disease. An early lytic gene of KSHV encodes viral interleukin-6 (vIL-6), a viral homologue of the proinflammatory cytokine and an autocrine/paracrine growth factor human IL-6. In this study, we examined the effects of suppressing vIL-6 expression in PEL cells with antisense peptide-conjugated phosphorodiamidate morpholino oligomers (PPMO). PPMO are ssDNA-analogues that have a modified backbone and enter cells readily. Treatment of PEL cells with a PPMO designed against vIL-6 mRNA led to a marked reduction in the proportion of vIL-6-positive cells detected by immunofluorescence assay. Analysis by Western blot confirmed a specific reduction in the vIL-6 protein level and showed that the reduction was dependent on the dose of vIL-6 PPMO. PEL cells treated with the vIL-6 PPMO exhibited reduced levels of cellular growth, IL-6 expression and KSHV DNA, and an elevated level of p21 protein. Treatment of PEL cells with a combination of two vIL-6 PPMO compounds targeting different sequences in the vIL-6 mRNA led to an inhibitory effect that was greater than that achieved with either PPMO alone. These results show that PPMO targeting vIL-6 mRNA can potently reduce vIL-6 protein translation and indicate that further exploration of these compounds in an animal model for potential clinical application is warranted.

Syphilis screening and intervention in 500,000 pregnant women in Shenzhen, the People's Republic of China

OBJECTIVES

To understand the disease epidemiology of syphilis in pregnant women, and to evaluate the effectiveness of the screening and intervention programme, for the purpose of controlling mother-to-child syphilis transmission in Shenzhen, in the People's Republic of China (PRC).

METHODS

At the Shenzhen Center for Disease Control and Prevention (SZCDC), we used the toluidine red unheated serum test (TRUST) for the primary screening of pregnant women, and confirmed positive results with the Treponema pallidum particle agglutination (TPPA) test. We informed and treated those with positive results. For the women who chose to proceed with the pregnancy, we clinically screened their babies for congenital syphilis using the 19S-IgM FTA-Abs test.

RESULTS

Between 1 July 2002 and 31 December 2005, we screened 477,656 pregnant women for syphilis, of whom 2208 (0.5%) tested positive. From 2003 to 2005, we collected epidemiological and treatment data from 2019 positive syphilis cases. Of these, 1855 (91.9%) of the pregnant women received treatment. Among the 1020 infants born to these women, 92 (9.0%) were confirmed to have congenital syphilis. If we exclude the mothers who had syphilis positive babies without undergoing prenatal screening, the project's success rate for mother-to-child transmission intervention was 99.1%.

CONCLUSIONS

After four years of implementation, we proved the programme to be successful in preventing mother-to-child syphilis transmission. Further work should be done to ensure the earlier screening and treatment of pregnant women.