First Report of Root and Stem Rot Caused by Phytophthora nicotianae on Peperomia tetraphylla in China

Peperomia tetraphylla, an evergreen herb, is becoming increasingly popular as a potted ornamental plant in southern China. In the summer of 2008, in some commercial flower nurseries in Shenzhen, Guangdong Province, P. tetraphylla showed extensive black stem and root rot, with leaves dropping from the rotten stem. Small pieces (approximately 3 mm²) of stems and leaves were excised from the margins of the black lesions, surface disinfected for 30 s to 1 min in 0.1% HgCl₂, plated onto potato dextrose agar (PDA), and incubated at 25°C in the dark. All the plated samples yielded Phytophthora, and microscopic examination of pure cultures grown on PDA plates showed arachnoid colonies with abundant aerial mycelium, chlamydospores, and a few sporangia. Numerous sporangia were formed in sterile soil extract. Sporangia were ovoid or obpyriform, noncaducous, with prominent solitary papillae, and measured 31 to 52 μm (average 38 μm) × 21 to 34 μm (average 27 μm). Chlamydospores were spherical and 21 to 34 μm in diameter (average 28 μm). The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using primers ITS₄/ITS₅ and sequenced (2). The ITS sequence, when submitted for a BLAST search in the NCBI database, showed 100% homology with the sequences of two reference isolates of Phytophthora nicotianae (Accession Nos. AY833526 and EU433396) and the consensus ITS sequence was deposited in the NCBI as Accession No. GQ499373. The isolate was identified as Phytophthora nicotianae on the basis of morphological and molecular characteristics (1). Pathogenicity of the isolate was confirmed by inoculating 1-year-old plants of P. tetraphylla growing in pots. The isolate was grown for 7 days on PDA plates and mycelial plugs, 5 mm in diameter and taken from the advancing margins of the colonies, were buried approximately 1 cm deep near the base of the stem in such a way that the mycelium on the plugs was in contact with the surface of the stem, which had been wiped earlier with 70% ethanol and gently wounded with a needle. Plants treated the same way but inoculated with sterile PDA plugs served as control plants. Three plants in each pot were inoculated and there were five replications each for the treatment and the control. All plants were kept in a greenhouse at 22 to 32°C. After 6 to 7 days, the inoculated plants showed black lesions around the mycelial plugs; symptoms of root and stem rot developed rapidly thereafter and the plants collapsed within 2 weeks. All symptoms on the inoculated plants were identical to those observed in naturally diseased plants, whereas the control plants remained healthy. The same fungus was consistently reisolated from the inoculated plants. To our knowledge, this is the first report of Phytophthora nicotianae on P. tetraphylla in China. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (2) J. B. Ristaino et al. Appl. Environ. Microbiol. 64:948, 1998.

The ability of human bispecific anti-idiotype antibody to elicit humoral and cellular immune responses in mice

Our goal is to compare the immunogenicity and the extent of immunologic reactivity between bispecific and mono anti-idiotype vaccines. We previously obtained two human anti-Id antibody fragments fuse5-G22, fuse5-I50 by phage display technology which were mimics of the antigens from nasopharyngeal carcinoma cell line (HNE2). In this study, we developed and characterized a bispecific anti-Id antibody vaccine G22-I50 and its parent monovalent antibody vaccines G22 and I50. The efficacy of G22-I50, G22, and I50 as tumor vaccines was evaluated in Balb/c mice with three injections of these vaccines adjuvanted with Freund's adjuvant. Mice immunized with G22-I50 exhibited comparable levels of antibody titers and stronger binding inhibition capabilities. Spleen cells from G22-I50-immunized mice gave a significant proliferative response and higher expression level of IFN-gamma and IL-2.These results suggested that bispecific anti-Id antibody vaccine was able to induce more powerful humoral and cell-mediated immune responses, which might make it to be a potential vaccine candidate for the therapy of nasopharyngeal carcinoma.

Expression and functional characterization of platelet-derived growth factor receptor-like gene

AIM: To investigate the role of platelet-derived growth factor receptor-like gene (PDGFRL) in the anti-cancer therapy for colorectal cancers (CRC).

METHODS: PDGFRL mRNA and protein levels were measured by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry in CRC and colorectal normal tissues. PDGFRL prokaryotic expression vector was carried out in Escherichia coli (E. coli), and purified by immobilized metal affinity chromatography. The effect of PDGFRL protein on CRC HCT-116 cells was detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT), clone counting, cell cycle, and wound healing assay.

RESULTS: Both RT-PCR and immunohistochemistry showed that the expression of PDGFRL in colorectal normal tissues was higher than in cancer tissues. Recombinant pET22b-PDGFRL prokaryotic expression vector was successfully expressed in E. coli, and the target protein was expressed in the form of inclusion bodies. After purification and refolding, recombinant human PDGFRL (rhPDGFRL) could efficiently inhibit the proliferation and invasion of CRC HCT-116 cells detected by MTT, clone counting and wound healing assay. Moreover, rhPDGFRL arrested HCT-116 cell cycling at the G0/G1 phase.

CONCLUSION: PDGFRL is a potential gene for application in the anti-cancer therapy for CRC.

Construction and selection of human Fab antibody phage display library of liver cancer

The aim of this study was to construct the fully humanized anti-hepatoma Fab fragment phage libraries and select antibodies against hepatoma specifically. PBMCs of liver cancer patients were immunized in vitro with HpeG(2) cells and were then transformed by Epstein-Barr virus (EBV). After total RNA was extracted, the heavy chain Fd and kappa/lambda light chain were amplified by RT-PCR and cloned into the vector pComb3 to construct the libraries of Fab fragments. The libraries were then panned by HpeG(2) cells. By means of ELISA and immunochemistry, the Fab phage antibodies binding with hepatoma were selected and identified. The Fd and light chain PCR products were subsequently inserted into pComb3, and the volume of Fab libraries reached 1.7 x 10(7). The libraries were enriched about 138-fold by three cycles of panning. 540 phage clones were picked randomly. Using cell ELISA and immunohistochemistry with cultured cells, one clone Fab phage antibody, which had binding activity with hepatoma, was picked out. Fully humanized anti-hepatoma Fab antibody phage display libraries were constructed. One phage clone was selected and confirmed to specifically bind to hepatoma cells. The selected Fab antibody may be further developed and applied to clinical diagnosis and therapy.

[Spatiotemporal expansion of urban and rural built-up areas in Shenyang City: an analysis based on remote sensing and GIS technology]

By using 1985, 1995, 1997, 2000 and 2004 satellite images and GIS technology, three indices including built-up area density, expansion intensity index, and fractal dimension were chosen to analyze the spatiotemporal characteristics, spatial differentiation, and morphological changes of urban and rural built-up areas in Shenyang City in 1985-2004, with the main driving factors discussed. In the study period, the high-density area of urban built-up area in the City increased year by year, and that of rural built-up area changed slightly before 1997 but increased gradually thereafter. The increased area, expansion speed, and expansion intensity of built-up area were evidently greater in urban than in rural area. An obvious spatial differentiation was observed in the expansion of built-up area between urban and rural areas, with the high-speed expansion mainly concentrated in urban area. The fractal dimension in urban area increased gradually, which meant that the integrated configuration of urban area became more and more complex, while that in rural area changed irregularly, because of the lack of reasonable planning and construction. Economic development, population growth, transportation, natural environment, policy-guiding, and urban planning were the main driving forces of the expansion of built-up areas in Shenyang City.

Gamma-aminobutyric acid promotes human hepatocellular carcinoma growth through overexpressed gamma-aminobutyric acid A receptor alpha 3 subunit

AIM

To investigate the expression pattern of gamma-aminobutyric acid A (GABAA) receptors in hepatocellular carcinoma (HCC) and indicate the relationship among gamma-aminobutyric acid (GABA), gamma-aminobutyric acid A receptor alpha3 subunit (GABRA3) and HCC.

METHODS

HCC cell line Chang, HepG2, normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction (PCR) for the expression of GABAA receptors. HepG2 cells were treated with gamma-aminobutyric acid (GABA) at serial concentrations (0, 1, 10, 20, 40 and 60 micromol/L), and their proliferating abilities were analyzed with the 3-(4, 5-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, cell doubling time test, colon formation assay, cell cycle analysis and tumor planted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed.

RESULTS

We identified the overexpression of GABRA3 in HCC cells. Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines, and found that GABA increased HCC growth in a dose-dependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells, but not GABRA3-knockdown HepG2 cells. This means that GABA stimulates HepG2 cell growth through GABRA3.

CONCLUSION

GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.

Effect of amended soil and hydraulic load on enhanced biological nitrogen removal in lab-scale SWIS

To characterize the effect of amended soil on nitrogen removal in subsurface wastewater infiltration system (SWIS), culture, grass carbon, and zeolite were mixed to produce microbial inoculums, and then the optimal microbial inoculums, nutrient substance, cinder, and original soil were mixed to produce the soils through bioaugmentation. Results indicate that the microbial inoculums (culture+50% grass carbon+50% zeolite) and the amended soil (12.5% microbial inoculums+25% nutrient substrate+12.5% cinder+50% original soil) have the optimal biogenic stimulating properties, and the adsorption capacity of the amended soil are 1.216 mg-Pg(-1) and 0.495 mg-Ng(-1). The laboratory soil column experiment indicates that the efficient mode of nitrogen removal in lab-scale SWIS is adsorption-nitrification-denitrification and the nitrification/denitrification can be enhanced by the application of the amended soil. On average, the SWIS filled with amended soil converts 85% of ammonia nitrogen (NH(4)(+)-N) to NO(x)(-)-N and removes 49.8-60.6% of total nitrogen (TN), while the system filled with original soil removes 80% of NH(4)(+)-N and 31.3-43.2% of TN at 4-8 cm day(-1). Two systems are overloads at 10 cm day(-1). It is concluded that the microbial activities and nitrogen removal efficiencies are improved in SWIS after bioaugmentation.

Fusion protein encoded by a CTLA-4 targeted DNA construct binds to human dendritic cells

Fusing antigens to cytotoxic T-lymphocyte antigen 4 (CTLA-4) represents an effective approach to enhance DNA vaccine efficacy. It has been speculated that the direct targeting of CTLA-4 fusion antigens to antigen-presenting cells (APCs) causes antigens to be processed and presented to T cells more efficiently, leading to a stronger immune response. In the present study, dendritic cells (DCs), the most potent APCs, were generated from human monocytes. The specific binding of CTLA-4 fusion protein to DCs was investigated by flow cytometry. The results showed that the CTLA-4 fusion protein was capable of binding to the B7 molecules on human DCs with specificity.

Mucosal and systemic immunization with targeted fusion anti-caries DNA plasmid in young rats

Early life vaccination is necessary to protect young children from dental caries. Our group had previously reported that a plasmid DNA vaccine pGJA-P/VAX against the glucosyltransferase (GTF) enzyme and cell surface antigen AgI/II (PAc) of Streptococcus mutans (S. mutans) elicited a specific and protective immunity in adult experimental animal models. In this report, early life immunization with the same plasmid was studied following intranasal (i.n.) and intramuscular (i.m.) delivery in murine models. The potential of inducing mucosal and systemic immune responses to special antigens was measured by ELISA. In addition, cytokine production and protection effectiveness against dental caries formation were also investigated. In the i.n. route, rats were primed when they were 5 days old, and boosted after 10 and 20 days with either plasmid pGJA-P/VAX-bupivacaine complexes, or pGJA-P/VAX alone, or empty vector. The pGJA-P/VAX-bupivacaine combination was able to mount the immune responses characterized by increased antibody levels of specific salivary IgA and serum IgG, preferential IFN-gamma production and significant reduction in the dental caries lesions. In the i.m. route, rats were vaccinated with either pGJA-P/VAX alone or empty vector with the same immunization schedule as the i.n. route. Plasmid pGJA-P/VAX alone induced a significant increase in the serum IgG and IFN-gamma production. However, it was not effective in eliciting specific salivary IgA and in decreasing the dental caries formation. All these findings indicate the feasibility of immunity with a targeted fusion DNA vaccine to a young immune system.

Gamma-aminobutyric acid promotes human hepatocellular carcinoma growth through overexpressed gamma-aminobutyric acid A receptor α3 subunit

AIM: To investigate the expression pattern of gamma-aminobutyric acid A (GABAA) receptors in hepatocellular carcinoma (HCC) and indicate the relationship among gamma-aminobutyric acid (GABA), gamma-aminobutyric acid A receptor α3 subunit (GABRA3) and HCC.

METHODS: HCC cell line Chang, HepG2, normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction (PCR) for the expression of GABAA receptors. HepG2 cells were treated with gamma-aminobutyric acid (GABA) at serial concentrations (0, 1, 10, 20, 40 and 60 μmol/L), and their proliferating abilities were analyzed with the 3-(4, 5-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, cell doubling time test, colon formation assay, cell cycle analysis and tumor planted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed.

RESULTS: We identified the overexpression of GABRA3 in HCC cells. Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines, and found that GABA increased HCC growth in a dose-dependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells, but not GABRA3-knockdown HepG2 cells. This means that GABA stimulates HepG2 cell growth through GABRA3.

CONCLUSION: GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.

Autoantibodies as potential biomarkers for nasopharyngeal carcinoma

Autoantibody signatures, as new biomarkers, may improve the early detection of nasopharyngeal carcinoma (NPC). We constructed a T7 phage cDNA library from mixed NPC tissues, and we isolated 31 tumor-associated proteins using biopan enrichment techniques with sera from NPC patients and from healthy population. DNA sequence analysis showed that among 31 phage-displayed proteins, 22 have sequence identity with known or putative tumor-associated proteins. The results of immunochemical reactivity of patients' sera with phage-expressed proteins showed enrichment in the number of immunogenic phage clones in the biopanning process and also confirmed that antibodies were present in the sera of patients but not in the sera of healthy donors. The autoantibody against phage-expressed protein MAGE, HSP70, Fibronectin, and CD44 measured by ELISA had greater predictive value than that against EBNA-1, respectively. The antibody levels against MAGE in sera positively correlated with the clinical stages of NPC, and the antibody levels against other three proteins partly correlated with the clinical stages of NPC. Our studies suggested that the autoantibodies against tumor-associated antigens in the sera of NPC patients could be used as a screening test for NPC. Studies of the corresponding proteins may have significances in tumor biology, novel drug development, and immunotherapy.

Injury-related fatalities in China: an under-recognised public-health problem

The May 2008 earthquake in Wenchuan drew attention to the important but largely unrecognised public-health problem of injury-related mortality and morbidity in China. Injuries account for more than 10% of all deaths and more than 30% of all potentially productive years of life lost due to premature mortality in China. Traffic-related injuries (mainly among cyclists and pedestrians), suicide, drowning, and falls account for 79% of all injury deaths. Rural injury death rates are double those of urban rates and male rates are double those of female rates. Despite an 81% increase in the traffic-related mortality from 1987 to 2006-associated with rapid motorisation-the overall injury mortality decreased by 17%, largely due to a surprising (and unexplained) 57% reduction in the suicide rate. Low-cost prevention measures that are most likely to produce large reductions in injury deaths include enforcement of laws for drinking and driving and for seat belt and helmet use, restriction of access to the most potent pesticides, and teaching children to swim. China needs to improve monitoring of fatal and non-fatal injuries, promote intersectoral collaboration, build institutional capacities, and, most importantly, mobilise community support and political will for investment in prevention.

Orexin A attenuates unconditioned sexual motivation in male rats

Orexins are neuropeptides involved in multiple neurophysiological functions such as reward and motivation. However, it is not clear whether orexins are implicated in sexual motivation. This study aims to evaluate the effects of orexin A and the OX(1)R antagonist SB334867 on unconditioned sexual motivation. Forty-five male Wistar rats are divided into four groups. The four groups are respectively administered intracerebroventricularly with saline, orexin A (1, 10 microg), 10% DMSO (cyclodextrin) and SB334867 (5, 15 microg) 10-15 min before sexual motivation tests. The preference for a receptive female to a male in an open arena with two tethered animals is designated as unconditioned sexual motivation. The results show that orexin A reduces the female preference (reducing time in the female zone and/or increasing time in the male zone), the number of visits for the female zone and the total distance traveled in sexually high-motivated males. SB334867 has no effect on the female preference, the number of visits and the distance traveled in either sexually high-motivated or low-motivated males. Our experiments reveal that centrally administered orexin A attenuates sexual motivation in high-motivated males although endogenous orexin A might not play an important role in the expression of unconditioned sexual motivation.

BMI-1 autoantibody in serum as a new potential biomarker of nasopharyngeal carcinoma

BMI-1 is overexpressed in a variety of cancers, which can activate the immune system to produce antibodies in tumor tissues. In this study, we isolated phage expressing BMI-1 protein by screening of a mixture of nasopharyngeal carcinoma (NPC) cDNA T7 phage library and found that the antibody against BMI-1 was elevated in the sera from NPC patients. BMI-1 mRNA was overexpressed at different levels in seven NPC cell lines compared with normal nasopharyngeal epithelial cell line NP69. Histochemistry showed that patient sera were more reactive with BMI-1 than normal sera. Antibody affinity assay using sera from 40 NPC patients and 54 controls showed that BMI-1 antibody was significantly greater in patient sera than in normal controls (patient 0.791 +/- 0.025 and normal 0.488 +/- 0.042; P < 0.001) and the BMI-1 autoantibody be significantly related with the progress of NPC (Benign versus LNPC P=0.001; LNPC versus MNPC P=0.047). Analysis of the results with logistic regression and receiver operating characteristics (ROC) curves showed that BMI-1 antibody was a modest marker for NPC (sensitivity 0.74 and specificity 0.73; AUC = 0.8044). The showed that BMI-1 antibody as a potential marker of NPC may be rational, and could have diagnostic and prognostic value.

[Urban landscape functional regionalization and development strategy in Shenyang City]

According to the topography, land type suitability and human activity, the urban area of Shenyang City was regionalized into four landscape functional regions, i.e., economic and cultural supporting region, ecological equilibrium region (including northern high plain equilibrium sub-region and southern low plain equilibrium sub-region), ecological supporting region (including eastern ecological supporting sub-region and western ecological supporting sub-region), and ecological barrier region. In economic and cultural supporting region, the radiation of function in economy and culture should be strengthened, and the natural and artificial green space system should be preserved. In ecological supporting region, environmentally friendly industries should be developed to provide diverse ecological service well. As a combination of natural and man-made ecological system, the ecological equilibrium region could balance and steady the other regional services. To keep the balance between artificial and natural landscapes in this region, it was needed to control the expansion of construction land, maintain the natural and semi-natural system, and build the ecological corridors to connect various natural system. In ecological barrier region, the ecological environment was in instability, where the protection and production should be dealt with equally.

[Landscape change in upper reaches of Minjiang River]

Based on the fuzzy logic knowledge database designed by NetWeaver tools, and using ecosystem management decision support system (EMDS), a quantitative evaluation was made on the landscape change in the upper reaches of Minjiang River from 1986 to 2000. The results showed that the type, area, amount, and spatial distribution of landscape patches in the reaches changed greatly, and the changing direction was in favor of ecosystem restoration. The changes of forest landscape mainly occurred in the north part of study area (Songpan County and Heishui County), while those of grass landscape mainly occurred both in the north part and in the furthest south part (Wenchuan County). The joint effect of increasing human activities and nature change was the driving force of the landscape changes.

Simulated microgravity inhibits the proliferation and osteogenesis of rat bone marrow mesenchymal stem cells

OBJECTIVES

Microgravity is known to affect the differentiation of bone marrow mesenchymal stem cells (BMSCs). However, a few controversial findings have recently been reported with respect to the effects of microgravity on BMSC proliferation. Thus, we investigated the effects of simulated microgravity on rat BMSC (rBMSC) proliferation and their osteogeneic potential.

MATERIALS AND METHODS

rBMSCs isolated from marrow using our established effective method, based on erythrocyte lysis, were identified by their surface markers and their proliferation characteristics under normal conditions. Then, they were cultured in a clinostat to simulate microgravity, with or without growth factors, and in osteogenic medium. Subsequently, proliferation and cell cycle parameters were assessed using methylene blue staining and flow cytometry, respectively; gene expression was determined using Western blotting and microarray analysis.

RESULTS

Simulated microgravity inhibited population growth of the rBMSCs, cells being arrested in the G(0)/G(1) phase of cell cycle. Growth factors, such as insulin-like growth factor-I, epidermal growth factor and basic fibroblastic growth factor, markedly stimulated rBMSC proliferation in normal gravity, but had only a slight effect in simulated microgravity. Akt and extracellular signal-related kinase 1/2 phosphorylation levels and the expression of core-binding factor alpha1 decreased after 3 days of clinorotation culture. Microarray and gene ontology analyses further confirmed that rBMSC proliferation and osteogenesis decreased under simulated microgravity.

CONCLUSIONS

The above data suggest that simulated microgravity inhibits population growth of rBMSCs and their differentiation towards osteoblasts. These changes may be responsible for some of the physiological changes noted during spaceflight.

Simulated microgravity inhibits the proliferation and osteogenesis of rat bone marrow mesenchymal stem cells

OBJECTIVES

Microgravity is known to affect the differentiation of bone marrow mesenchymal stem cells (BMSCs). However, a few controversial findings have recently been reported with respect to the effects of microgravity on BMSC proliferation. Thus, we investigated the effects of simulated microgravity on rat BMSC (rBMSC) proliferation and their osteogeneic potential.

MATERIALS AND METHODS

rBMSCs isolated from marrow using our established effective method, based on erythrocyte lysis, were identified by their surface markers and their proliferation characteristics under normal conditions. Then, they were cultured in a clinostat to simulate microgravity, with or without growth factors, and in osteogenic medium. Subsequently, proliferation and cell cycle parameters were assessed using methylene blue staining and flow cytometry, respectively; gene expression was determined using Western blotting and microarray analysis.

RESULTS

Simulated microgravity inhibited population growth of the rBMSCs, cells being arrested in the G(0)/G(1) phase of cell cycle. Growth factors, such as insulin-like growth factor-I, epidermal growth factor and basic fibroblastic growth factor, markedly stimulated rBMSC proliferation in normal gravity, but had only a slight effect in simulated microgravity. Akt and extracellular signal-related kinase 1/2 phosphorylation levels and the expression of core-binding factor alpha1 decreased after 3 days of clinorotation culture. Microarray and gene ontology analyses further confirmed that rBMSC proliferation and osteogenesis decreased under simulated microgravity.

CONCLUSIONS

The above data suggest that simulated microgravity inhibits population growth of rBMSCs and their differentiation towards osteoblasts. These changes may be responsible for some of the physiological changes noted during spaceflight.

[Edge effects of forest landscape in upper reaches of Minjiang River]

By using GIS and RS techniques, the edge effects of forest landscape in the upper reaches of Minjiang River, Sichuan Province of China were studied on landscape scale. The results showed that there was a distinct boundary between forestland and farmland, with the vegetation changed significantly. The biomass at forestland edge was lower than that in forestland interior, with the edge effect width being 60 m, whereas the biomass in farmland exterior was higher than that in farmland interior, with the edge effect width being 60-90 m. Forestland-grassland boundary was naturally formed and changed gradually. The biomass at forestland edge was lower than that in forestland interior, while that at grassland edge was higher than that in grassland interior, with the edge effect being 60 m for forestland and 45-75 m for grassland. The edge effect of forestland-shrub land boundary was similar to that of forestland-grassland boundary, with the edge effect width being 60 m for forestland and 45-75 m for shrub land.

The type I Lanyu pig has a maternal genetic lineage distinct from Asian and European pigs

The Lanyu pig is an indigenous breed from Lanyu Islet, located south-east of Taiwan, with phenotypic characteristics distinctive from other pig breeds in Asia and Europe. Based on geographic considerations, the Lanyu pig may have originated from mainland China, Austronesia or the Ryukyu Islands. In the present study, polymorphism of the mitochondrial DNA control region sequence was used to clarify phylogenetic relationships among two herds of Lanyu pigs imported before 1980 from Lanyu Islet into Taiwan and reared in isolation on two different farms. Two distinct mitochondrial control region haplotypes were found. The type I Lanyu sequence appeared independently as a unique clade different from Asian and European pig sequences, while the type II Lanyu sequence was clustered within the major Asian clade. The pairwise distances between the major Asian clade vs. the type I Lanyu and European clades were 0.01726 +/- 0.00275 and 0.01975 +/- 0.00212 changes per site respectively. Estimates of divergence time suggest that the type I Lanyu sequence split from the major Asian pig clade in prehistoric times. The type II Lanyu mtDNA shares a close genetic lineage with Japanese Satsuma and New Zealand Kune Kune mtDNA with pairwise distances of 0.00095 +/- 0.00000 and 0.00192 +/- 0.00000 respectively, indicating gene flow between Lanyu Islet, Japan and Oceania in recent times. Together these results indicate that the type I Lanyu pig has a genetic lineage separate from Asian-type pigs, while the type II Lanyu sequence may represent a more recent introgression of modern Asian pigs.

Microscopic and Macroscopic Studies of the Development of Puccinia hemerocallidis in Resistant and Susceptible Daylily Cultivars

Infection and colonization of eight daylily cultivars, which varied in resistance to daylily rust, by Puccinia hemerocallidis was studied macroscopically and microscopically. After germination of urediniospores, appressoria formed at the tip of germ tubes and the fungus penetrated the host through stomatal openings 2 days after inoculation (DAI). Under the infection sites, intercellular hyphae aggregated and formed uredia, which released urediniospores 8 DAI. Resistant cultivars, characterized by the development of rapid death of host cells, were separated into three qualitative categories based on absence and presence of necrotic lesions without or with sporulation. In highly resistant cvs. Prairie Blue Eyes and Bertie Ferris, no macroscopic disease symptoms were observed on leaf surfaces although a few collapsed cells were detected microscopically. Both resistant and moderately resistant reactions were characterized by necrotic lesions with many collapsed cells under infection sites. The difference between these two reactions was that uredia and urediniospores were observed in the moderately resistant cv. Chicago Apache, but not in resistant cvs. Buttered Popcorn and Stella De Oro. Susceptible cultivars, characterized by the absence of a hypersensitive response, were separated into two qualitative categories based on restriction of intercellular hyphal growth that delayed development of uredia and formation of urediniospores. Compared to the susceptible cv. Pardon Me, moderately susceptible cvs. Mary Todd and Chorus Line had a delayed latent period and reduced amount of sporulation. The results indicate that hypersensitive cell death is one of the resistance responses to daylily rust. Necrotic lesions on leaf surfaces are associated with the number of collapsed host cells. Delayed latent period and reduced sporulation that resulted from restriction of intercellular hyphal growth could represent another type of resistance response in the daylily-rust pathosystem.