Search

In karst regions, forests often grow on bedrock outcrops, however the water sources used by the forest vegetation are not known. This study aimed at investigating whether there were seasonal shifts (dry/wet season) of water sources for plants growing on the continuous dolostone outcrops, and comparing their differences with those growing on nearby thin soils in karst areas of southwest China. Rainwater, soil water within 0-30 cm depths, spring water (as a reflection of local deep water sources) and plant xylem water were sampled in March (late dry season) and July (mid rainy season) 2009, respectively. A direct inference approach and the IsoSource mixing model were used to estimate the contributions of different sources to the plant xylem water. On the outcrops, the deciduous tree species Radermachera sinica mainly used deep water sources during the dry season and a mixture of rainwater and deep water sources during the wet season. By contrast, the deciduous small shrub Alchornea trewioides largely relied on recent rainwater during both dry and wet seasons. Three non-deciduous species ( Sterculia euosma, Schefflera octophylla and Ficus orthoneura) appear to rely on deep water sources during the wet seasons. In nearby thin soils, R. sinica mainly utilized deep water in the dry season and a mixture of soil water and deep water in the wet season. A. trewioides relied on the same water sources (rainwater-derived soil water) in the different seasons. The above results indicate that inter-specific differences in rooting patterns and leaf phenologies may lead to the differences in the sources of water used by coexisting plant species in karst regions. [ABSTRACT FROM AUTHOR]

Ophraella communa (Coleoptera: Chrysomelidae) is a leafbeetle that is unintentionally introduced in China. It is a potential biological control agent against common ragweed, Ambrosia artemisiifolia (Asterales: Asteraceae). The effects of temperature on the development and fecundity of 0. communa were studied at eight constant temperature regimens (15, 20, 22, 25, 28, 30, 32, 36°C) in the laboratory. The results showed that the developmental periods for egg, larva, pupa, and entire immature stages decreased in response to the increasing temperature, with the exception of 30°C. The survival rates at different developmental stages were higher at 25 and 28°C than at other temperatures. Ovipositional period and longevity of female shortened with the increasing temperature. The highest fecundity of female was observed to be 2,712.3 eggs/female at 28°C. Life table of 0. communa was constructed based on the data at 20 -32°C. The innate capacity for increase (rm), the net reproductive rate (R0),and the finite rate of increase (λ) reached the maximum at 28°C, with values of 0.247, 1,773.0, and 1,280, respectively. The shortest period of a generation (T) was 24.6 d at 32°C, whereas the longest T value was recorded as 79.3 d at 20°C. These results offer valuable insight on the establishment potential of 0. communa in new environments with diverse temperature regimens and on its massrearing techniques in laboratory. [ABSTRACT FROM AUTHOR]

Ophraella communa, an unintentionally introduced leaf beetle in China, has good control efficiency on ragweed, Ambrosia artemisiifolia. Aspects of the climatic requirements for development, survival, longevity and fecundity of O. communa were studied under the conditions of constant temperature (25 ± 1°C), photoperiod of 14 L:10 D and three relative humidities (60%, 75% and 90% RHs). The results showed that the developmental periods of O. communa at different stages shortened along with the increasing relative humidity, except that of the pupal stage. Although no differences were observed in the pupal survival rate, ovipositional period, fecundity, longevity and adult female age-specific survivorship of O. communa under the three humidity conditions, the survival rates during the egg, larva and entire immature stage were significantly higher at 75% RH and 90% RH than at 60% RH. The innate rate of increase ( rm), net reproductive rate ( R0), finite rate of increase ( λ) reached the maximum at 75% RH, with values of 0.181, 1116.4 and 1.198, respectively. These results indicated that the optimum relative humidity for the development of O. communa ranged from 75% RH to 90% RH. Thus O. communa prefers moist microclimate habitats. Its population may expand rapidly during mid-May to late August in south, east and central China, when the humidity is relatively high. [ABSTRACT FROM AUTHOR]

The MAGE-A3 protein, one of the promising tumor antigens for immunotherapy, is highly expressed in human hepatocellular carcinoma (HCC). In this study, we estimated the specific CD8+ T cell immune response to MAGE-A3 p271–279 peptide (M3271) in the peripheral blood of HCC patients without antigen vaccination in order to evaluate its immunotherapeutic potential in these patients. After expansion in vitro, the functional IFN-γ producing M3271 specific CD8+ T cells were detected in 30.8% (8/26) of HLA-A2+MAGE-A3+ HCC patients. The effector CD8+ T cells could release cytotoxic molecules of granzyme B and perforin after restimulation with natural HLA-A2+MAGE-A3+ HCC cell lines in the samples tested. The functional supertype of HLA-A2 in the presentation of HLA-A*0201 restricted M3271 peptide has been identified in the Chinese HCC patients of Han ethnicity, that widely expanded the applicability of this tumor peptide vaccine in Chinese HCC patients. Thus, the functionally detectable pre-existence of M3271-specific CD8+ T cells in HCC patients makes M3271 a potential target for immunotherapy in these patients. The responsive CD8+ T cells to both NY-ESO-1 and MAGE-A3 antigens provide a rationale for the application of a bivalent vaccine in HCC patients with tumors expressing both antigens. [ABSTRACT FROM AUTHOR]

Background. A correlation between melanomaassociated antigen (MAGE) A1 mRNA expression and genome-wide hypomethylation has been observed in some carcinomas, but this relationship is not known in hepatocarcinoma. Methods. Total RNA and genomic DNA were prepared from ten human hepatocarcinoma cell lines in which the genetic characteristics are stable. MAGE-1 mRNA expression was determined by reverse transcription polymerase chain reaction (RTPCR), and the level of genome-wide demethylation was evaluated by enzyme digestion and Southern-blot assay. The methylation status of the MAGE-A1 gene promoter was measured by enzyme digestion and PCR. Results. MAGE-A1 mRNA was detected in the hepatocarcinoma cell lines QGY-7703, SMMC-7721, HLE, BEL-7402, BEL-7404, and BEL-7405, which showed moderate to low levels of cell differentiation. In contrast, MAGE-A1 mRNA expression was not detected in the hepatoma cell lines HepG2215, HepG2, QGY-7701, and Huh7, which showed moderate to high levels of differentiation. The level of demethylation in MAGE-A1 mRNA-positive cell lines was much higher than that in MAGE-A1 mRNA-negative cell lines (P = 0.02). Conclusions. The results suggest that MAGE-A1 mRNA expression in human hepatoma cell lines is associated with hypomethylation of the genome and the MAGE-A1 promoter domain. This study will be helpful to reveal the expression mechanisms of MAGE-like tumor antigens in cancer cells. [ABSTRACT FROM AUTHOR]

Chronic infection with hepatitis B virus (HBV) constitutes a major global public health threat, causing substantial disease burdens such as liver cirrhosis and hepatocellular carcinoma, thus representing high unmet medical needs. Currently available therapies are safe, well tolerated, and highly effective in decreasing viremia and improving measured clinical outcomes with low rates of antiviral resistance. However, long-term management remains a clinical challenge, mainly due to the slow kinetics of HBV surface antigen clearance. In this article, we review emerging antivirals directed at novel targets derived from mechanisms of viral cellular entry, viral replication, viral assembly, and the host immune response, leading to preclinical and clinical trials for possible future therapeutic intervention. The recent therapeutic advances in the development of all categories of HBV inhibitors may pave the way for regimens of finite duration that result in long-lasting control of chronic hepatitis B infection.

Aim: To explore a rapid and easy sequencing method for hepatitis C virus (HCV) genome and establish a new sequencing method in China., Methods: Polymerase chain reaction (PCR) was combined with a DNA sequencing technique. PCR products were purified by agarose gel electrophoresis, polyacrylamide gel electrophoresis (PAGE) and polyethylene glycol (PEG) respectively. Then, in the presence of a 5' labeling PCR primer, purified PCR products were directly sequenced. By this method, HCV NS5b cDNA from two HCV infected individuals (HC-42 and HC-49) were sequenced., Results: PCR directed sequencing worked best using PCR amplified DNA purified by electrophoresis as a sequencing template. When sequencing a large number of templates, the purification step can be bypassed by using a lower concentration of dNTPs (40 μmol of each dNTP) and primers (10 pmol of each primer) in the first stage of PCR. The aliquot of the first stage of PCR mixture was then directly used for amplification of chain terminated products but the sequencing ladders generated were of low intensity. Polyethylene glycol (PEG) could not remove nonspecific products of PCR, which affected the sequencing result to a certain extent and generated a background in sequencing ladders. Compared with the reported HCVJ and HC-C2, a new three nucleotide deletion was found in HC-42., Conclusion: PCR directed sequencing is a rapid, simple and effective method, especially for sequencing large samples. A three nucleotide deletion was first reported.