Plant diversity increases spatial stability of aboveground productivity in alpine grasslands

Plant diversity can significantly affect the grassland productivity and its stability. However, it remains unclear how plant diversity affects the spatial stability of natural grassland productivity, especially in alpine regions that are sensitive to climate change. We analyzed the interaction between plant (species richness and productivity, etc.) and climatic factors (precipitation, temperature, and moisture index, etc.) of alpine natural grassland on the Qinghai-Tibetan Plateau. In addition, we tested the relationship between plant diversity and spatial stability of grassland productivity. Results showed that an increase in plant diversity significantly enhanced community productivity and its standard deviation, while reducing the coefficient of variation in productivity. The influence of plant diversity on productivity and the reciprocal of productivity variability coefficient was not affected by vegetation types. The absolute values of the regression slopes between climate factors and productivity in alpine meadow communities with higher plant diversity were smaller than those in alpine meadow communities with lower plant diversity. In other words, alpine meadow communities with higher plant diversity exhibited a weaker response to climatic factors in terms of productivity, whereas those with lower plant diversity showed a stronger response. Our results indicate that high plant diversity buffers the impact of ambient pressure (e.g., precipitation, temperature) on alpine meadow productivity, and significantly enhanced the spatial stability of grassland productivity. This finding provides a theoretical basis for maintaining the stability of grassland ecosystems and scientifically managing alpine grasslands under the continuous climate change.

Warming differentially affects above- and belowground ecosystem functioning of the semi-arid alpine grasslands

Rapid climate warming is altering multiple ecosystem functions of alpine grasslands. However, the responses of the above- and belowground ecosystem multifunctionality (EMF) to climate warming might exhibit difference in semi-arid alpine grasslands. Based on manipulative field experiments at an alpine meadow and an alpine steppe, we explored warming effects on the functioning of alpine grassland ecosystems on the Tibetan Plateau. Warming significantly decreased plant diversity and aboveground biomass, but tended to increase belowground biomass, soil carbon, and soil nutrient contents. Experimental warming generally had neutral effects on the EMF of both alpine grasslands. Nevertheless, warming differentially affects the above- and belowground ecosystem functioning of Tibetan semi-arid alpine grasslands, with the aboveground EMF (AEMF) deceased but the belowground EMF (BEMF) increased under warmer conditions. Our results further showed that the negative effect of experimental warming on AEMF was mainly regulated by the changes of plant and soil biodiversity. However, plant productivity had a pivotal role in propelling the positive effect of warming on BEMF. Our results emphasized the potential impacts of plant and soil biodiversity, productivity, and soil nutrients in maintaining the EMF of alpine grasslands, which could offer novel views for sustainable management of Tibetan semi-arid alpine ecosystems.

Warming positively promoted community appearance restoration of the degraded alpine meadow although accompanied by topsoil drying

On-going climate warming is threatening the ecological function of grassland ecosystems. However, whether warming has positive effects on community microhabitats and appearance, especially in degraded grasslands, remains elusive. To address this issue, we conducted a 2-year field experiment on the severely degraded alpine meadow and undegraded alpine meadow with no warming and warming treatments. Community coverage and height in degraded meadow significantly increased under warming, while these changes were not significant in undegraded meadow. Two-year warming increased the community height of degraded meadow and undegraded meadow by 56.55% and 10.99%, respectively. Warming also increased community coverage by 41.88% in degraded meadow and decreased community coverage by 3.01% in undegraded meadow. Moreover, the response of topsoil temperature to warming was stronger in degraded meadow (6.89%) than in undegraded meadow (- 0.26%), while the negative response of topsoil moisture to warming was weaker in degraded meadow (- 13.95%) than in undegraded meadow (- 20.00%). The SEMs further demonstrated that warming had positive effects on topsoil temperature and community height, while had negative effects on topsoil moisture both in degraded and undegraded meadows. Our results confirm that warming-induced soil drying is an important pathway affecting the community appearance in alpine meadows. These findings highlight that warming has positive effects on community height and coverage and is particularly effective in improving community coverage appearance in severely degraded alpine meadow with topsoil drying.

Warming-driven indirect effects on alpine grasslands: short-term gravel encroachment rapidly reshapes community structure and reduces community stability

The community stability is the main ability to resist and be resilient to climate changes. In a world of climate warming and melting glaciers, alpine gravel encroachment was occurring universally and threatening hillside grassland ecosystem. Gravel encroachment caused by climate warming and glacial melting may alter community structure and community stability in alpine meadow. Yet, the effects of climate warming-induced gravel encroachment on grassland communities are unknown. Here, a 1-year short-term field experiment was conducted to explore the early stage drive process of gravel encroachment on community structure and stability at four different gravel encroachment levels 0%, 30%, 60%, and 90% gravel coverage at an alpine meadow on the Qinghai Tibetan Plateau, by analyzing the changes of dominant species stability and species asynchrony to the simulated gravel encroachment processes. Gravel encroachment rapidly changed the species composition and species ranking of alpine meadow plant community in a short period of time. Specifically, community stability of alpine meadow decreased by 61.78-79.48%, which may be due to the reduced dominant species stability and species asynchrony. Species asynchrony and dominant species stability were reduced by 2.65-17.39% and 46.51-67.97%, respectively. The results of this study demonstrate that gravel encroachment presents a severe negative impact on community structure and stability of alpine meadow in the short term, the longer term and comprehensive study should be conducted to accurate prediction of global warming-induced indirect effects on alpine grassland ecosystems.

Natural compensation mechanism of soil water infiltration through decayed roots in semi-arid vegetation species

In arid and semi-arid areas, unsuitable afforestation programs may cause soil water deficit and even, in some cases, deep-soil desiccation and the subsequent death of part of the vegetation. However, the benefits of preferential flow through decayed root channels for supplying water in the dried soil layers are rarely evaluated. This study examines the effects of root channels on soil water content (SWC) and infiltration (initial and steady-state) in two planted species with high drought tolerance, namely: Korshinsk peashrub (Caragana korshinskii Kom.), and red plum apricot (Armeniaca vulgaris Lam.), using bare land as control site and published data from alfalfa (Medicago sativa L.) plots to refine results analysis. The infiltration rates were measured using a double-ring infiltrometer in areas with alive and decayed roots; and methylene blue was used to trace the pathways of water flow. The highest SWC appeared in the Korshinsk peashrub land, whereas the alfalfa grassland had the lowest SWC; and the differences of SWC among treatments were significant at all soil layers. Korshinsk peashrub had the highest steady infiltration rates, which were about 23% and 83% higher than those rates measured in the fruit tree plantation and alfalfa grasslands, respectively. The steady infiltration rates were significantly and positively correlated with the average root diameter and area. Within the same species, the decayed root plots significantly increased the soil water infiltration capacity compared to the alive root plots. Considering the water scarcity conditions of the study area, the preferential flow formed through decomposed roots was conducive to soil water supplement, appearing as a natural compensation mechanism caused by dead vegetation. Our findings contribute to a better understanding of soil water infiltration during root decay of the plants in water-limited ecosystems, and how this dynamic replenishes soil moisture and alleviates soil desiccation.

Detection of antibiotics in the urine of children and pregnant women in Jiangsu, China

Exposure to low concentrations of antibiotics links to multiple health hazards, such as drug resistance of bacteria, and childhood obesity. In this study, seven antibiotics were measured in the urine of 107 children and 126 pregnant women in Jiangsu Province by ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS). The overall urinary antibiotics detection rate was 38.6%. Most (98.3%) of the participants' antibiotics concentrations were no more than 10 ng/mL. Children had a significantly higher detection rate than pregnant women (47.7% vs. 31.0%, P = 0.009), as well as the concentration (95th percentile: 6.49 vs. 4.08 ng/mL, P = 0.002). The detection rates of individual antibiotics ranged from 0.4% to 15.0%, and the concentrations ranged from lower than the limit of detection (LOD) through up to 31.96 ng/mL individually. Two or more antibiotics were detected in 11.2% of the urines. Tetracyclines were more frequently detected than phenicols (30.9% vs.12.4%). Oxytetracycline was the most frequently detected (15.0%). Multivariate logistic regression showed that consuming puffed food every day was associated with a significantly increased likelihood of detection, and higher concentration of overall antibiotics, and of doxycycline. Children were more likely to be detected of doxycycline and florfenicol, and to have elevated concentration of doxycycline, compared with pregnant women. This study highlights the relatively heavier antibiotics exposure in children, and a possible impact of puffed food on it, which needs to be warranted in future studies.

Soil functional biodiversity and biological quality under threat: intensive land use outweighs climate change

Climate change and land use intensification are the two most common global change drivers of biodiversity loss. Like other organisms, the soil meso-fauna are expected to modify their functional diversity and composition in response to climate and land use changes. Here, we investigated the functional responses of Collembola, one of the most abundant and ecologically important groups of soil invertebrates. This study was conducted at the Global Change Experimental Facility (GCEF) in central Germany, where we tested the effects of climate (ambient vs. 'future' as projected for this region for the years between 2070 and 2100), land use (conventional farming, organic farming, intensively-used meadow, extensively-used meadow, and extensively-used pasture), and their interactions on the functional diversity (FD), community-weighted mean (CWM) traits (life-history, morphology), and functional composition of Collembola, as well as the Soil Biological Quality-Collembola (QBS-c) index. We found that land use was overwhelmingly the dominant driver of shifts in functional diversity, functional traits, and functional composition of Collembola, and of shifts in soil biological quality. These significant land use effects were mainly due to the differences between the two main land use types, i.e. cropland vs. grasslands. Specifically, Collembola functional biodiversity and soil biological quality were significantly lower in croplands than grasslands. However, no interactive effect of climate × land use was found in this study, suggesting that land use effects on Collembola were independent of the climate change scenario. Overall, our study shows that functional responses of Collembola are highly vulnerable to land use intensification under both climate scenarios. We conclude that land use changes reduce functional biodiversity and biological quality of soil.

Trade-off between surface runoff and soil erosion during the implementation of ecological restoration programs in semiarid regions: A meta-analysis

The application of ecological restoration programs, related to water resources protection and soil erosion control, may have some undesirable outcomes. An important example is the effect that vegetation restoration may have in reducing surface water resources. After searching peer-reviewed articles, we selected 38 publications from 16 countries in comparable areas - semiarid conditions (aridity index <0.5), surface coverage >50% and fine soil texture - to evaluate the effectiveness of different types of vegetation (i.e., forestland, scrubland and grassland) in regulating runoff and sediment transport. In particular, we used three indices: the runoff reduction effect, the sediment reduction effect and the ratio between runoff and sediment reduction. These indices were calculated from measured data reported in the original articles. Results showed that scrubland had higher runoff reduction effect (59% in gentle slopes; 65% in steep slopes) than in grassland (39% on gentle slopes; 43% on steep slopes) and forestland (33% on gentle slopes; 51% on steep slopes). For the three types of vegetation, the sediment reduction effect was >70%. Concerning the ratios between runoff and sediment reduction, grassland showed the lowest ratios (56% on gentle slopes; 53% on steep slopes) compared to forestland (63% on gentle slopes; 65% on steep slopes) and scrubland (93% on gentle slopes; 81% on steep slopes). Our results indicate that low values of ratios between runoff and sediment reduction are the most suitable because they indicate an effective soil erosion and sediment delivery reduction but maintaining surface runoff. Overall, our study demonstrates that grassland may be the best choice for optimizing the trade-off between catchment water yield and soil conservation during the implementation of ecological restoration programs in semi-arid regions.

Effect of three artificial aging techniques on physicochemical properties and Pb adsorption capacities of different biochars

Biochar is beneficial for soil amendment, but further research is still required on changes in its physicochemical properties during aging, especially in oxygen-containing functional groups and associated adsorption behaviors. Here, we used two different biochars, apple tree branch biochar and maize stalk biochar, and simulated the aging process by using freeze-thaw cycles, dry-wet cycles, and chemical oxidation methods. We investigated the changes in the physicochemical properties and Pb adsorption behavior of the biochars before and after aging treatments. The characterization results showed that the biochar surface structure changed after aging treatments. In general, the specific surface areas (SSAs) of the two biochars increased after chemical oxidation treatment but decreased after the other two treatments. The elemental content analyses indicated a decrease in the C content and increase in O content after artificial aging. In addition, the content of oxygen-containing functional groups in most biochars is increasing after treatment. The increase or decrease in SSA resulted in an increase or decrease in adsorption sites, respectively, thereby enhancing or reducing the adsorption capacity of the biochar. Furthermore, oxygen-containing functional groups enhanced the Pb adsorption capacity of biochar by complexation of free carboxyl and hydroxyl functional groups with Pb. Our research indicated that aging can lead to changes in the Pb adsorption capacity of biochar and that these changes vary depending on the type of aging and biochar. Our results will help to provide a better understanding of the changes in physicochemical properties and Pb adsorption capacity of biochar during the aging process in soil toward making full use of biochar for soil amendment.

Grazing exclusion promotes grasses functional group dominance via increasing of bud banks in steppe community

To understand the bud banks response to grazing exclusion, we conducted a demographic experiment in long-term grazing exclusion (20 year and 30 year) typical steppe. Results showed that grass functional group constituted the vast majority of the aboveground vegetation and belowground bud bank in all treatments. Long-term grazing exclusion significantly increased total aboveground biomass (2.5 and 2.6 times in 20y and 30y grazing exclusion grasslands, respectively), and decreased total stem density (31% and 37% in 20y and 30y grazing exclusion grasslands, respectively). Grazing exclusion for 20 and 30 years increased grass aboveground biomass respectively by 6.0 and 8.0 times, and decreased grass stem density by 38% and 33%. Grazing exclusion had different effects on belowground bud density of grass and forb functional group. Long-term grazing exclusion significantly increased plant buds and bud bank size (25% and 37% in 20y and 30y grazing exclusion grasslands, respectively), especially for grass functional group (49% and 95% in 20y and 30y grazing exclusion grasslands, respectively), but had no significant effects on forb bud density. Changes of aboveground community were significantly related to changes of belowground bud bank under both grazing and grazing exclusion grasslands. The bud bank density of grass functional group was significantly positive with total (R² = 0.33, P < 0.05) and grass aboveground biomass (R² = 0.36, P < 0.01), while negative related with total (R² = -0.27, P < 0.05) and grass stem density (R² = -0.22, P < 0.05). Grazed grasslands, 20y and 30y grazing exclusion grasslands all were not meristem limited and had large reserve bud banks, which would completely replace the aboveground stem population during the growing season. These findings indicate that grazing exclusion could not only improve a large bud bank for grassland restoration but also improve the dominance of grass functional group by increasing grass belowground bud banks in typical steppe community. We propose that the belowground bud bank might be a good approach to indicating potential succession direction of aboveground community.

Studies on the reaction mechanism of Cu/SiC catalytic oxidation for degradation of methyl orange in presence of microwave

The removal of methyl orange (MO) in a copper-loaded silicon carbide (Cu/SiC) system under microwave (MW) irradiation was studied. Cu/SiC was synthesized by employing an impregnation method and the effects of parameters such as reaction time, catalyst dosage, hydrogen peroxide (H₂O₂) dosage, microwave power and pH on the rate of degradation of MO were also studied. The obtained results showed that almost complete degradation was obtained in the presence of Cu/SiC catalyst within 8 min of irradiation when 100 mL of MO solution (20 mg/L), 3 ml/L of H₂O₂, 2 g/L of catalyst dose, 600 W of MW power, and pH 7 were applied. The Cu-bearing catalyst with H₂O₂ formed a Fenton-like system and the rate of generation of hydroxyl radicals (·OH) was also accelerated by subjecting to MW. From the kinetic analysis, it is revealed that the degradation of MO using the MW-Cu/SiC-H₂O₂ system follows the pseudo-first-order.

Phytoextraction of rhenium by lucerne (Medicago sativa) and erect milkvetch (Astragalus adsurgens) from alkaline soils amended with coal fly ash

Coal fly ash (CFA) is an industrial waste generated in huge amounts worldwide, and the management of CFA has become an environmental concern. Recovery of valuable metals from CFA is one of the beneficial reuse options of CFA. Rhenium (Re) is one of the rarest metals in the Earth's crust and one of the most expensive metals of strategic significance in the world market. A CFA at the Jungar Thermal Power Plant, Inner Mongolia, China, contains more Re than two alkaline soils in the surrounding region. Pot experiments were undertaken to grow lucerne (Medicago sativa) and erect milkvetch (Astragalus adsurgens) in a loessial soil and an aeolian sandy soil amended with different rates (5%, 10%, 20%, and 40%) of CFA. The results show that plant growth was considerably enhanced and Re concentration in plants was significantly increased when CFA was applied to the alkaline soils at rates of ≤20%; while in some cases plant growth was also markedly enhanced by the 40% CFA treatment, which increased plant Re concentration the most of all treatments. Both lucerne and erect milkvetch showed potential for phytoextracting Re from CFA-amended alkaline soils. Using CFA for soil amendment not only offers a potential solution for the waste disposal problem of CFA, but the phytoextraction of Re by both lucerne and erect milkvetch may also bring an economic profit in the future.

Lysobacter korlensis sp. nov. and Lysobacter bugurensis sp. nov., isolated from soil

Two Gram-reaction-negative, rod-shaped, gliding, yellow-pigmented bacterial strains, designated ZLD-17T and ZLD-29T, were isolated from arid soil samples collected from Xinjiang Province, north-west China, and subjected to analysis using a polyphasic taxonomic approach. Both novel strains required 1.0–2.0 % (w/v) sea salts for optimal growth. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these two strains belong to the genus Lysobacter within the class Gammaproteobacteria. Strain ZLD-17T showed highest 16S rRNA gene sequence similarities to Lysobacter capsici KCTC 22007T (96.9 %), Lysobacter spongiicola DSM 21749T (96.8 %) and Lysobacter koreensis KCTC 12204T (96.8 %), whereas strain ZLD-29T showed highest sequence similarities to Lysobacter niastensis DSM 18481T (96.0 %) and Lysobacter enzymogenes DSM 2043T (95.9 %). 16S rRNA gene sequence similarity between ZLD-17T and ZLD-29T was 96.1 %. The DNA G+C contents of strains ZLD-17T and ZLD-29T were 67.9 and 68.2 mol%, respectively. The major cellular fatty acids of both strains were summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C17 : 1ω9c, iso-C16 : 0, C16 : 0 and iso-C11 : 0 3-OH; their predominant isoprenoid quinone was Q-8 and their major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Based on their phenotypic characteristics, phylogenetic position as determined by 16S rRNA gene sequence analysis and chemotaxonomic data, strains ZLD-17T ( = CCTCC AB 207174T  = KCTC 23076T) and ZLD-29T ( = CCTCC AB 207175T = KCTC 23077T) represent two novel species of the genus Lysobacter, for which the names Lysobacter korlensis sp. nov. and Lysobacter bugurensis sp. nov. are proposed, respectively.

Bacillus deserti sp. nov., a novel bacterium isolated from the desert of Xinjiang, China

A Gram-positive, rod-shaped, motile and spore-forming bacterium, designated ZLD-8(T), was isolated from a desert soil sample collected from Xinjiang Province in north-west China, and subjected to a polyphasic taxonomic analysis. This isolate grew optimally at 30°C and pH 7.0. It grew with 0-4% NaCl (optimum, 0-1%). Comparative 16S rRNA gene sequence analysis showed that strain ZLD-8(T) was closely related to members of the genus Bacillus, exhibiting the highest 16S rRNA gene sequence similarity to Bacillus kribbensis DSM 17871(T) (98.0%). The levels of 16S rRNA gene sequence similarity with respect to other Bacillus species with validly published names were less than 96.3%. The DNA G + C content of strain ZLD-8(T) was 40.1 mol%. The strain contained MK-7 as the predominant menaquinone. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids (>5% of total fatty acids) were anteiso-C15:0 (39.56%), iso-C14:0 (25.69%), C16:1 ω7c alcohol (10.13%) and iso-C15:0 (5.27%). These chemotaxonomic results supported the affiliation of strain ZLD-8(T) to the genus Bacillus. However, low DNA-DNA relatedness values and distinguishing phenotypic characteristics allowed genotypic and phenotypic differentiation of strain ZLD-8(T) from recognized Bacillus species. On the basis of the polyphasic evidence presented, strain ZLD-8(T) is considered to represent a novel species of the genus Bacillus, for which the name Bacillus deserti sp. nov. is proposed. The type strain is ZLD-8(T) (=CCTCC AB 207173(T) = KCTC 13246(T)).

Grazing Disturbances Mediate Species Composition of Alpine Meadow Based on Seed Size

Seed size has been considered a key factor influencing the dynamics of plant communities, but few empirical, within-community predictions have been made based on seed size. Data on species density, biomass, frequency, and seed size were measured in alpine meadows with different grazing gradients in Northwest China. Seed mass variance and range within community were analyzed and relationships between seed size and density, biomass, and frequency within community were evaluated. Our results showed that vegetation height, coverage, and productivity decreased significantly with increasing grazing intensity. Species richness and total individual density were greatest in moderately-grazed meadow. Mean seed mass, mean coefficient of variation of seed mass, and seed mass range within community showed a consistent trend of moderately-grazed meadow > ungrazed meadow > heavily-grazed meadow. Correlation analyses showed that seed size was positively related to species density, biomass, and frequency within community in ungrazed meadow, but was negatively related to species density, biomass, and frequency within community in heavily-grazed meadow. Our study suggests that grazing disturbance can alter the relationship between seed size and dominance for coexistent species within communities. With increasing grazing intensity, the advantages of species density, biomass, and frequency were switched from the larger-seeded species to the smaller-seeded species within the community.

Seed mass in Kobresia-dominated communities in alpine meadows at two different elevations

Many different selection stresses could affect seed mass. We collected evidence in support of the hypothesis that there exists a significant positive effect of altitude on both intraspecific and interspecific changes in seed mass. We weighed 71 seed species, including 44 species that occurred in both low-altitude and high-altitude Kobresia communities in alpine meadows of the Qinghai—Tibetan plateau. We calculated average seed mass, seed mass variance within community, and seed mass range for the Kobresia community at two altitudes. In 50% of the 44 common seed species, mass increased with altitude, but in the other 50%, mass decreased. Average seed mass within communities decreased with altitude. There was no single significant relationship, positive or negative, between seed mass and altitude for all species in the two Kobresia communities. The unique species in the low-altitude site presented a larger mean seed than the unique species in the high-altitude site. However, the higher-altitude Kobresia community had a lower average community seed mass and seed mass range than the low-altitude community. Our results indicated that mean seed mass of each species responded to altitude within community, but did not show a uniform trend for seed mass change between communities along altitudinal gradients.

IFN-gamma is associated with risk of Schistosoma japonicum infection in China

Before the start of the schistosomiasis transmission season, 129 villagers resident on a Schistosoma japonicum-endemic island in Poyang Lake, Jiangxi Province, 64 of whom were stool-positive for S. japonicum eggs by the Kato method and 65 negative, were treated with praziquantel. Forty-five days later the 93 subjects who presented for follow-up were all stool-negative. Blood samples were collected from all 93 individuals. S. japonicum soluble worm antigen (SWAP) and soluble egg antigen (SEA) stimulated IL-4, IL-5 and IFN-gamma production in whole-blood cultures were measured by ELISA. All the subjects were interviewed nine times during the subsequent transmission season to estimate the intensity of their contact with potentially infective snail habitats, and the subjects were all re-screened for S. japonicum by the Kato method at the end of the transmission season. Fourteen subjects were found to be infected at that time. There was some indication that the risk of infection might be associated with gender (with females being at higher risk) and with the intensity of water contact, and there was evidence that levels of SEA-induced IFN-gamma production were associated with reduced risk of infection.

[Clonning and identification of the gene encoding specific IgE antibody-related antigen of Schistosoma japonicum]

OBJECTIVE

To obtain the gene encoding specific IgE-related antigen of Schistosoma japonicum from the cDNA library of adult Schistosoma japonicum.

METHODS

The pooled sera from 15 individuals with high levels of specific IgE antibody against SWAP were absorbed with Protein-G and used for screening of IgE-related antigen from the adult worm cDNA library of Schistosoma japonicum. The inserted cDNA was amplified by PCR and sequenced. According to the first reading frame of the sequence, a pair of new probes, in which EcoR I and Not I sites were incorporated respectively, were designed and used to amplify the target gene. Then, the gene was cloned into vector pGEM-T and subcloned into expression vector pGEX-6p-1. The fusion protein was expressed, analysed by SDS-PAGE and identified by Western blotting with the specific IgE antibody, respectively.

RESULTS

The inserted cDNA fragment from the positive clone was about 1,200 bp, with the ORF of 507 bp which encoded 169 amino acids. The deduced molecular weight of the recombinant protein was 19.3 kDa. The homology between the target gene (Sj43B) and other known DNA sequences was less than 40%. The fusion protein expressed by the recombinant vector pGEX-6p-1/Sj43B could be recognized by schistosome specific IgE antibody.

CONCLUSION

Sj43B may encode the specific IgE-related antigen of Schistosoma japonicum. The successful construction of recombinant plasmid pGEX-6p-1/Sj43B lay the groundwork for further studies on immunological characteristics and protection immunity of the recombinant protein.

[Cloning and identification of deltamethrin-resistance or susceptibility associated genes of Culex pipiens pallens]

OBJECTIVE

To obtain deltamethrin-resistance or susceptibility associated genes of Culex pipiens pallens.

METHODS

The differentially expressed genes were obtained by suppression subtractive hybridization (SSH), and identified by cDNA microarray and reverse Northern blotting.

RESULTS

523 and 286 clones were selected respectively in the two directional SSH. 155 and 42 genes were respectively expressed 2-3 and > 3 times higher in the insecticide-resistant strain than in the susceptible strain; 15 and 9 genes were respectively expressed 2-3 and > 3 times higher in the susceptible strain than in the resistant strain. There were 2 genes only expressed in the insecticide-resistant strain. 51 three times differentially expressed clones and 2 specially expressed clones were sequenced. 44 sequences were obtained which belong to 13 new genes. There were 8 over-expressed genes in resistant strain, 7 of which were similar respectively to mitochondrion rRNA gene, 60S ribosomal protein gene, 40S ribosomal protein S4 gene, trypsin gene, chymotrypsin A gene, ospin gene, and 16S ribosomal RNA gene. There were 5 over-expressed genes in susceptible strain, 2 of them being similar with 40S ribosomal protein S29 gene and myosin regulatory light chain 2 gene. In addition, 2 genes specially expressed in resistant strain were similar respectively to glycogen branching enzyme gene and ribosomal protein 46 gene.

CONCLUSION

The differentially expressed genes may be associated with deltamethrin-resistance or susceptibility of Culex pipiens pallens.

[Analysis of the mitochondria-related protein of Schistosoma japonicum and its antigen epitopes]

OBJECTIVE

To sequence the cloned gene Sj338 and to identify the encoded protein and its antigen epitopes.

METHODS

The Sj338 gene fragment obtained from adult S. japonicum cDNA library amplified by PCR method was subcloned into pGEM-T vector for sequencing. The sequence of nucleotides and the characteristics of the encoded protein were analyzed by DNASIS Program and Goldkey DNA and Protein Analytical Program, and then the homology of the amino acid sequence was searched on the BLAST net.

RESULTS

The cloned rSj338 gene was demonstrated to be 487 bp containing one 459 bp ORF, encoding a protein consisted of 153 amino acids with a molecular weight of 17.6 kDa. The amino acid sequence of the recombinant protein rSj338 shared 46% identity with that of the corresponding part of human mitochondrial import receptor and 44% identity with that of the Rattus sp. mitochondrial precursor receptor. The possible antigen epitopes were predicted within the peptide fragments of 26-32 aa, 37-46 aa and 147-151 aa.

CONCLUSION

The protein encoded by rSj338 gene fragment might be the mitochondria-related protein of Schistosoma japonicum.

[Human parasite antigen-specific IFN-gamma response in schistosomitsis japonica endemic area]

OBJECTIVE

To explore the characteristics of human schistosome antigen-specific IFN-gamma response in a population in an area endemic for schistosomiasis japonica.

METHODS

Three neighboring villages were chosen on Nanshan Island of Poyang Lake. 65 egg-negative persons and 64 egg-positive ones were selected randomly from the residents aged 14-41 years according to the egg counts by Kato-Katz thick smear method. IFN-gamma was measured in the whole blood culture supernatant after stimulated by the schistosome soluble egg antigen (SEA) and soluble worm antigen preparations (SWAP). Serum isotype-restricted antibody was detected by ELISA.

RESULTS

IFN-gamma levels induced by both SEA and SWAP were increased significantly after praziquantel treatment. The SEA-specific IFN-gamma level of the uninfected group was much higher than that of the reinfected group. A negative correlation between IFN-gamma level and IgG4 production was found, reflecting that IFN-gamma might be associated with the resistance to schistosome reinfection.

CONCLUSION

The changes in IFN-gamma level might play an important role in association with the resistance to schistosome reinfection.

[Studies on human cytokine responses before and after praziquantel chemotherapy in an endemic area of schistosomiasis japonica]

OBJECTIVE

To observe the cellular immune responses in a population of an endemic area of schistosomiasis japonica and the influence of praziquantel treatment.

METHODS

Blood was taken from 129 residents (64 cases were egg-positive, 65 cases were egg-negitive) of an endemic area of Poyang Lake before and 45 days after praziquantel treatment. Cytokines induced by the schistosome soluble egg antigen (SEA) and soluble worm antigen preparations (SWAP) in the peripheral blood cells including IL-5, IL-10 and IFN-gamma were measured.

RESULTS

Among 129 cases, the cytokine levels were found much higher in egg negative individuals than in egg-positive individuals. The cytokine levels induced by both antigens were increased significantly after praziqantel treatment especially IL-5 and IFN-gamma.

CONCLUSION

The cellular immune responses in the population in schistosomiasis japonica endemic area exhibited a general trend of down-regulation and were elevated significantly after praziquantel treatment.

[Gene cloning and characterization of mitochondria-related protein of Schistosoma japonicum]

OBJECTIVE

To subclone and characterize a cDNA clone coding for Schistosoma japonicum (S.j.) mitochondria-related protein.

METHODS

The open reading frame of the fragment(Sj338/24) obtained from an adult worm cDNA library of S.j. was analysed, at the upstream and downstream of the open reading frame(ORF) the primers A and B were designed, respectively, and the cDNA fragment was used as PCR template. The Sj338 gene fragment obtained was amplified by PCR method and then subcloned into pGEM-T vector for sequencing. The gene sequence was analyzed and the target fragment was restrictedly digested and subcloned into expression vector pGEX-6P-1. The expressed recombinant protein was purified and characterized.

RESULTS

The cloned Sj338 gene was demonstrated to be 487 bp long containing one 459 bp ORF, encoding a protein with a molecular weight of 17 kDa. The nucleotide sequence of the cloned gene Sj338 had higher homology with those genes coding for mitochondrial outer membrane protein of Homo sapiens and Rattus norvegicus. The recombinant construct of pGEX-6P-1/Sj338 could be expressed efficiently and the antigenicity of its product rSj338 has been demonstrated by Western blotting.

CONCLUSION

Sj338 may be the gene coding for S.j. mitochondria-related protein and the recombinant protein may be used as a new vaccine candidate.

[Cloning and identification of cytochrome P450 resistance related genes in the mosquito, Culex pipiens pallens]

OBJECTIVE

To inquire into the relationship between cytochrome P450 and deltamethrin resistance.

METHODS

24 new cDNA sequences encoding cytochrome P450 were amplified respectively from deltamethrin-susceptible and -resistant strains of Culex pipiens pallens with a pair of degenerate primers according to the conservative amino acid sequences of CYP4 in insects by RT-PCR and the Direct Cloning Method, and then were identified by cDNA chip and reverse Northern.

RESULTS

112 positive clones were obtained, of which 24 were shown to be new sequences encoded for cytochrome P450. They have been lodged in GenBank and were appraised by the Nomenclature Committee of Cytochrome P450, belonging to the subfamily CYP4C, CYP4D, CYP4H and CYP4J in CYP4 family. The hybrid signal values of 6 P450 sequences (NYDS3, NYDS5, NYDR6, NYDR9, NYDR15 and NYDR17) were 3.1-9.7 times higher in the resistance probe than in the susceptible probe, and NYDR17 only reacted with the resistance probe. The result of reverse Northern in NYDR15 was similar to that of cDNA chip.

CONCLUSION

CYP4 is related to deltamethrin resistance and the specific expression caused by point mutation of cytochrome P450 gene may exist in deltamethrin-resistant Cx. pipiens pallens.

Down-regulation of specific antigen-driven cytokine production in a population with endemic Schistosoma japonicum infection

Schistosome antigen-driven cytokine responses and antischistosome antibody levels of residents of a Schistosoma japonicum endemic island in Poyang Lake, Jiangxi Province were studied before and 45 days after treatment with praziquantel. IL-4, IL-5, IL-10 and INF-gamma were all detected in the supernatants of whole-blood cultures after stimulation with schistosome soluble egg antigen (SEA) and soluble worm antigen preparation (SWAP). The percentages of subjects producing detectable amounts of each cytokine assayed were higher in the group who were negative by stool examination at the start of the study than in those who were initially stool positive. After praziquantel treatment the percentages of subjects producing both type I and type II cytokines increased. This suggests that the production of both types of cytokine was down-regulated in the presence of live, egg-laying S. japonicum adult worms but that this was reversible by treatment. In contrast, the antibody studies showed higher levels of SWAP and SEA-specific antibodies (IgE, total IgG, IgG4, IgM) in subjects who were originally stool-positive than in those who were stool-negative. After treatment specific IgE responses were elevated, but total IgG and IgG4 anti-SEA and IgM anti-SWAP antibody levels all fell significantly.

[Studies of the genetic polymorphism of Schistosoma japonicum (Chinese mainland strains)]

In order to analyze the interspecies diversity and the extent of diversity among Schistosoma japonicum Chinese mainland strains, the genetic variation on gene level among 6 isolates collected from Jiangxi, Hunan, Hubei, Anhui, Sichuan, Yunnan and a cultured isolate from a laboratory were studied using molecular biological technique. There were only two different bases at position 112 and 143 in 536 bp sequence of 28S rDNA-D2 domain between Anhui and Yunnan isolates, the homology was 99.6%. The result could be explained the reason of why the migration rates of single chain 28S rDNA-D2 domain among the above 7 isolates were the same completely in PCR-SSCP. However, comparing with the sequences of the Philippine isolate of S. japonicum, S. mansoni and S. aematobium, there were 6, 94 and 93 different bases and the homologies were 98.9, 82.5 and 82.7 per cent separately. With 8 restriction endonucleases to analyze the ITS of rDNA obtained by PCR from the 7 isolates, the results showed that only 3 minor bands were different, e.g. 5.3% of total 58 fragments. It was suggested that the ITS of rDNA among 7 isolates were highly conserved. Using randomly amplified polymorphic DNA (RAPD) to analyze the genetic diversity of the genomes of the 7 isolates, the average genetic distance (D) calculated from total 284 amplified fragments was 0.22. The maximum D was 0.30 and existed between Anhui and Yunnan isolates. The minimum D was 0.13 and existed between Sichuan and Yunnan isolates. The clustering analysis of genetic distances showed that the 7 isolates could be gathered in one group. From above three results, it could be considered that the genetic diversity on gene level among S. japonicum Chinese mainland strains was very low.

[A case-control study on risk factors for definite and borderline hypertension]

To study the risk factors for definite and borderline hypertension (HBP), a pair-matched case-control study was conducted with data from the outpatient service of department of internal medicine in Tianjin Binjiang Hospital in 1991-1992. The cases were selected from 312 patients with definite and borderline HBP diagnosed during period 1990-1992 and those newly identified during the survey. The controls were selected from other subjects with no histories of cardiovascular disease and matched by age and sex. The conditional logistic regression model was used by definition of definite and borderline HBP for analysis. The results showed that the risk factors for developing definite or borderline HBP were: family history of HBP, lower level of education, higher weight or body mass index (kg/m2). The association of all these variables with definite HBP were more significant than that with borderline HBP.

[Video-assisted thoracoscopic surgery for chest disease]

Video-assisted thoracoscopic surgery was applied in a total of 20 patients, since Dec. 1992. There were 16 man and 4 woman whose ages ranged from 20 to 65 years. Three patient had a wedge resection for lung tumors, one a lobectomy for tracheaectasy, eleven with recurrent spontaneous pneumothorax were successfully treated, Pleural tumors (n = 1), pulmonary cyst (n = 1), Three biopsy of lung. The advantages of this for patients include cosmetic considerations, a shorter operation period, low pain, earlier postoperation mobilization.

The association between breast cancer and diet and other factors

To explore the effects of diet and other factors on breast cancer development, a case-control study was conducted in Tianjin between 1986-87. After adjusting for confounding factors, it was found that factors associated with increased risk of breast cancer included --early age at menarche; late age at menopause; late age at first birth; high Qutelet's index; histories of breast wound, disease and benign tumor; and a family history of malignant tumor, high fat, high calorie, low vegetable intake; elevated serum cholesterol and LDL-cholesterol; and lower levels of serum HDL-cholesterol and whole blood selenium.

Gas-filled liposomes as echocardiographic contrast agents in rabbits with myocardial infarcts

RATIONALE AND OBJECTIVES

The authors evaluated gas-filled liposomes as echocardiographic contrast agents in rabbits with myocardial infarcts.

METHODS

Ten rabbits underwent ligation of the left anterior descending coronary artery. Five animals underwent echocardiography before and after production of myocardial infarct (MI) and four animals had post-MI imaging only. In either case, images were obtained before and after injection of a single dose of 1 mL of gas-filed liposomes. Three radiologists blinded to clinical information reviewed the pre- and postcontrast images and assessed endomyocardial border definition, wall motion, confidence levels for normal versus abnormal wall motion and visualization of papillary muscle and mitral valve.

RESULTS

Postcontrast scans showed significant improvement (P < .05) in endomyocardial border definition, visualization of wall motion, papillary muscle and mitral valve as well as increased reader confidence level.

CONCLUSIONS

These results are encouraging and suggest that gas-filled liposomes may be a useful contrast agent for echocardiography.

Immunodiagnosis of Schistosoma japonicum infection in China

Diagnosis is an essential prerequisite for the control programs of schistosomiasis. Chinese scientists have been making efforts for decades towards the development of immunological approach in an attempt to offer alternatives of or supplements to parasitological diagnosis. The authors outline briefly the main advances in the research of immunodiagnosis for schistosomiasis japonica in China in two catalogues: antibody detection and antigen detection. A number of immunodiagnostic assays based on antibody detection, which have been used widely in the control programs in China, are appraised in terms of sensitivity and specificity, and the achievements in the development of immunodiagnostic assays based on antigen detection are introduced. Readers will find some information concerning the efforts so far made by Chinese scientists in the improvement of immunodiagnosis by use of molecular approach, including search for biochemically and/or immunochemically isolated and/or purified antigens, recombinant antigens and anti-idiotypic reagents of diagnostic interest to construct defined antigen-antibody systems for diagnosis, and development of monoclonal antibody-based assays for antibody or antigen detections.

Liposomes as MR contrast agents: pros and cons

Liposomes are generally thought of as being useful for entrapping drugs within their internal aqueous space. When used with MR contrast agents, this has the drawback that water flux across the membrane bilayer is limiting to contrast enhancement. This can be partially overcome by making the liposomes very small, such that surface area is relatively great compared to internal volume, thereby facilitating water exchange. Alternatively the membranes can be designed to be permeable to water but this may render the vesicles unstable in serum. Another approach is to incorporate the contrast agents into the lipid bilayer. By designing novel complexes of manganese with the ligands incorporated onto dual acyl chains, we have achieved R1 and R2 values of over 20/mmol sec-1 or more than five times higher than Gd-DTPA. Hepatic metastasis detection is significantly improved in rats at doses of only 10 mumol/kg manganese. Membrane-bound manganese complexes function as highly effective liver imaging agents and merit further study for development as agents to undergo human clinical trials.

[1:R matched case-control studies with fixed and varying numbers of controls]

This paper introduces the use of the Mantel-Haenszel estimator in 1:R matched case-control studies with fixed and varying numbers of controls matched to each case. The new methods of variance estimator of the Mantel-Haenszel estimator of a common odds ratio were provided. These methods were also summarized into the method of calculating table in order to present a simple, convenient and easily understanding method for the readers.

[Studies on DNA methylation in transformed mouse liver cells]

Activity of DNA methylase and DNA methylation level were measured from normal mouse liver, mouse liver charged with H22a ascitic hepatoma and H22a ascitic hepatoma cell by measuring incorporation of H3-methyl. S-Adenosyl-3H-methyl-methionine (3H-SAM) was used as methyl donor. DNA methylation level of different cells were measured by HP-LC. DNA methylase activity and DNA methylation level of H22a ascitic hepatoma, mouse liver charged with H22a ascitic hepatoma are lower than normal mouse liver. Treatments of antitumor drugs lead to a rising of DNA methylase activity of tumor cell, however, the DNA methylation level of tumor cell has not rised after such treatments.