The functional quality of decomposing litter outputs from an Arctic plant community is affected by long-term exposure to enhanced UV-B

Plant exposure to enhanced UV-B radiation typically induces changes in leaf secondary metabolite profiles which will be inherited in litter, affecting litter breakdown and the carbon (C) dynamics of sensitive plant communities. A key enzyme in the decomposition process is phenol oxidase which is influenced by litter quality and, hence, a decomposition bioindicator. Here we investigated dwarf shrub litter decomposition following experimental community exposure to enhanced UV-B over two decades in the Swedish sub-Arctic. We examined the hypothesis that foliar UV-B exposure would alter litter quality to elevate phenol oxidase activity. This was tested in the field by measuring phenol oxidase activity in freshly collected mixed-community litter from under our experimental vegetation. A laboratory mesocosm was next used in a decomposition assay to investigate individual species responses over eight weeks, with an emphasis on the quality of leachate outputs from decomposing litter (from Empetrum hermaphroditum, Vaccinium vitis-idaea, Vaccinium uliginosum). In the assay bi-weekly collections of leachate were analysed for phenol oxidase activity, together with total phenolics and dissolved organic C (DOC). At the end of the assay litter mass loss and respired C were also determined. The initial assessment on field mixed-community litter found no enhanced UV-B treatment (henceforth: ‘UV-B treatment’) effect on phenol oxidase activity. However, in the controlled laboratory mesocosm assay, significant species-specific effects of the UV-B treatment were evident, with increased phenol oxidase activity in V. vitis-idaea leachate (P < 0.001) and a significant reduction (P = 0.05) in respired C. Leachate DOC release from the UV-B treatment was greater in both Vaccinium species and the effect on V. uliginosum was significant (P < 0.05). The UV-B treatment had no effect on the total phenolic concentration of litter or leachates for any species, but there were significant differences in leachate total phenolics, both over time and between species. Also the initial phenolic concentration in leachates from the decomposing litter of E. hermaphroditum was greater than both Vaccinum species. Results suggest a species specific role for UV-B in influencing enzyme function and decomposition, dependent on individual traits. This has implications for decomposition dynamics in this system and more widely. Our study highlights the value of using a laboratory assay to gain a mechanistic understanding the species level impacts of a global change factor (UV-B) on decomposition, which are otherwise obscured by community-level responses and difficult to determine under field conditions.     

Influence of Different Forest System Management Practices on Leaf Litter Decomposition Rates,Nutrient Dynamics and the Activity of Ligninolytic Enzymes: A Case Study from Central European Forests

Leaf litter decomposition is the key ecological process that determines the sustainability of managed forest ecosystems, however very few studies hitherto have investigated this process with respect to silvicultural management practices. The aims of the present study were to investigate the effects of forest management practices on leaf litter decomposition rates, nutrient dynamics (C, N, Mg, K, Ca, P) and the activity of ligninolytic enzymes. We approached these questions using a 473 day long litterbag experiment. We found that age-class beech and spruce forests (high forest management intensity) had significantly higher decomposition rates and nutrient release (most nutrients) than unmanaged deciduous forest reserves (P<0.05). The site with near-to-nature forest management (low forest management intensity) exhibited no significant differences in litter decomposition rate, C release, lignin decomposition, and C/N, lignin/N and ligninolytic enzyme patterns compared to the unmanaged deciduous forest reserves, but most nutrient dynamics examined in this study were significantly faster under such near-to-nature forest management practices. Analyzing the activities of ligninolytic enzymes provided evidence that different forest system management practices affect litter decomposition by changing microbial enzyme activities, at least over the investigated time frame of 473 days (laccase, P<0.0001; manganese peroxidase (MnP), P = 0.0260). Our results also indicate that lignin decomposition is the rate limiting step in leaf litter decomposition and that MnP is one of the key oxidative enzymes of litter degradation. We demonstrate here that forest system management practices can significantly affect important ecological processes and services such as decomposition and nutrient cycling.     

UV-B辐射对马尾松凋落叶分解和养分释放的影响

由大气臭氧层减薄导致的UV-B辐射变化将直接影响到凋落物的分解。目前,有关UV-B辐射影响木本植物凋落物分解的研究还很少,在国内还没有开展。采用分解袋法开展了马尾松凋落叶在自然环境和UV-B辐射滤减两种辐射环境下的分解试验。结果表明：在UV-B辐射滤减环境下的马尾松凋落叶年分解速率比对照环境减慢了47.74%。UV-B辐射极显著(p<0.01)地加快了马尾松凋落叶的分解速率,促进了凋落叶中碳、磷、钾的释放和木质素的降解,对氮的释放无明显影响。研究结果意味着UV-B辐射将加快马尾松林的营养循环速度,降低马尾松林凋落物层的碳储量。     

Direct and indirect effects of solar ultraviolet-B radiation on long-term decomposition

As a result of stratospheric ozone depletion, more solar ultraviolet-B radiation (UV-B, 280–315 nm) is reaching the Earth's surface. Enhanced levels of UV-B may, in turn, alter ecosystem processes such as decomposition. Solar UV-B radiation could affect decomposition both indirectly, by changes in the chemical composition of leaves during growth, or directly by photochemical breakdown of litter and through changes in decomposer communities exposed to sunlight. In this experiment, we studied indirect and direct effects of solar UV-B radiation on decomposition of barley (Hordeum vulgare). We used barley straw and leaf litter grown under reduced UV-B (20% of ambient UV-B) or under near-ambient UV-B (90% of ambient UV-B) in Buenos Aires, Argentina, and decomposed the litter under reduced or near-ambient solar UV-B for 29 months in Tierra del Fuego, Argentina. We found that the UV-B treatment applied during growth decreased the decay rate. On the other hand, there was a marginally significant direct effect of elevated UV-B during the early stages of decomposition, suggesting increased mass loss. The effect of UV-B during growth on decomposition was likely the result of changes in plant litter chemical composition. Near-ambient UV-B received during plant growth decreased the concentrations of nitrogen, soluble carbohydrates, and N/P ratio, and increased the concentrations of phosphorus, cellulose, UV-B-absorbing compounds, and lignin/N ratio. Thus, solar UV-B radiation affects the decomposition of barley litter directly and indirectly, and indirect effects are persistent for the whole decomposition period.     

Effects of Acid on Plant Litter Decomposition in an Arctic Lake

The effects of acid on the microbial decomposition of the dominant aquatic macrophyte (Carex sp.) in Toolik Lake, Alaska were studied in microcosms during the ice-free season of 1980. Toolik Lake is slightly buffered, deep, and very oligotrophic. Microbial activities, as determined by ¹⁴C-acetate incorporation into extractable lipids, associated with Carex litter were significantly (P < 0.01) reduced within 2 days at pHs of 3.0 and 4.0, but not 5.0, 5.5, or 6.0, as compared with ambient controls (pH 7.4). ATP levels were significantly reduced at pH 3.0, but not at the other pHs tested. After 18 days, microbial activity significantly correlated with weight loss (P < 0.05), nitrogen content (P < 0.01), and C/N ratios (P < 0.01) of the litter, but did not correlate with ATP levels. Scanning electron microscopy of the litter surface revealed that the fungi present at ambient pH did not become dominant at pHs below 5.5, diatoms were absent below pH 4.0, and bacterial numbers and extracellular slime were greatly reduced at pH 4.0 and below. Mineralization of Carex¹⁴C-lignin-labeled or ¹⁴C-cellulose-labeled lignocellulose was reduced at pH 2.0, but not at pH 4.0, 5.0, or 6.0, compared with controls (pH 7). We concluded that if the pH of the water from this slightly buffered lake was sufficiently reduced, rates of litter decomposition would be significantly reduced.     

Effects of Litter Addition on Ectomycorrhizal Associates of a Lodgepole Pine (Pinus contorta) Stand in Yellowstone National Park

Increasing soil nutrients through litter manipulation, pollution, or fertilization can adversely affect ectomycorrhizal (EM) communities by inhibiting fungal growth. In this study, we used molecular genetic methods to determine the effects of litter addition on the EM community of a Pinus contorta stand in Yellowstone National Park that regenerated after a stand-replacing fire. Two controls were used; in unmodified control plots nothing was added to the soil, and in perlite plots perlite, a chemically neutral substance, was added to maintain soil moisture and temperature at levels similar to those under litter. We found that (i) species richness did not change significantly following perlite addition (2.6 ± 0.3 species/core in control plots, compared with 2.3 ± 0.3 species/core in perlite plots) but decreased significantly (P < 0.05) following litter addition (1.8 ± 0.3 species/core); (ii) EM infection was not affected by the addition of perlite but increased significantly (P < 0.001) in response to litter addition, and the increase occurred only in the upper soil layer, directly adjacent to the added litter; and (iii) Suillus granulatus, Wilcoxina mikolae, and agaricoid DD were the dominant organisms in controls, but the levels of W. mikolae and agaricoid DD decreased significantly in response to both perlite and litter addition. The relative levels of S. granulatus and a fourth fungus, Cortinariaceae species 2, increased significantly (P < 0.01 and P < 0.05, respectively) following litter addition. Thus, litter addition resulted in some negative effects that may be attributable to moisture-temperature relationships rather than to the increased nutrients associated with litter. Some species respond positively to litter addition, indicating that there are differences in their physiologies. Hence, changes in the EM community induced by litter accumulation also may affect ecosystem function.     

The influence of elevated ultraviolet-B radiation (UV-B) on tissue quality and decomposition of loblolly pine (Pinus taeda L.) needles

Stratospheric ozone depletion is expected to elevate the influx of ultraviolet-B radiation (UV-B) to the biosphere. Increased levels of UV-B may, in turn, alter important ecosystem processes such as decomposition. Previous studies have shown that growth under elevated UV-B can alter leaf quality in angiosperm species and thereby indirectly change subsequent rates of leaf decay. In this experiment, we determined if elevated UV-B would alter the chemical composition and decay of needle tissue from two seed sources of the gymnosperm Pinus taeda L. Maryland and Virginia seed sources of P. taeda were grown in the field for 3 years beneath lampbanks supplying either ambient, low elevated or high elevated UV-B. These levels of UV-B corresponded to 0, 16 and 25% stratospheric ozone depletion at the experimental site in Beltsville, MD (39 degrees N). Needles were collected from six randomly chosen plants for each combination of seed source and UV-B level. The needle samples were analyzed for total C and N, UV-B absorbing compounds, and carbon fractions. Decay rates were also determined by measuring rates of CO(2) evolution from needle material decomposed under laboratory conditions. UV-B did not significantly alter the chemical composition of needles from the Virginia seed source. In contrast, needles from the Maryland seed source tended to have elevated lignin/N ratios and a lower holocellulose content when grown under the highest level of UV-B. Furthermore, while needles from the Virginia pines did not have UV-B altered decay rates, Maryland needles grown under low elevated UV-B conditions decomposed 36% more rapidly than needles from other treatments. Results from this experiment illustrate at least three characteristics about the indirect effect of UV-B on decomposition, (1) UV-B can modify decomposition of tissue from gymnosperms as well as angiosperms; (2) UV-B effects on tissue chemistry and decay may not only be species-specific but also seed-source specific; and (3) UV-B effects on decomposition may not increase with increasing UV-B dose.     

The Association of Platelet Count with Clinicopathological Significance and Prognosis in Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

ObjectiveElevated platelet count (PC), a measure of systemic inflammatory response, is inconsistently reported to be associated with poor prognosis in patients with renal cell carcinoma (RCC). We conducted a systematic review and meta-analysis to clarify the significance of PC in RCC prognosis.MethodsPubMed, Embase, and Web of Science databases were searched to identify eligible studies to evaluate the associations of PC with patient survival and clinicopathological features of RCC.ResultsWe analyzed 25 studies including 11,458 patients in the meta-analysis and categorized the included articles into three groups based on RCC stage. An elevated PC level was associated with poor overall survival (OS, hazard ratio [HR] 2.24, 95% confidence interval [CI] 1.87-2.67, P<0.001) and cancer-specific survival (CSS, HR 2.59, 95% CI 1.92-3.48, P<0.001) when all stages were examined together; with poor CSS (HR 5.09, 95% CI 2.41-10.73, P<0.001) and recurrence-free survival (HR 6.68, 95% CI 3.35-13.34, P<0.001) for localized RCC; with poor OS (HR 2.00, 95% CI 1.75-2.28, P<0.001) for metastatic RCC; and with poor OS (HR 2.05, 95% CI 1.04-4.03, P = 0.038), CSS (HR 3.38, 95% CI 1.86-6.15, P<0.001), and PFS (HR 2.97, 95% CI 1.47-6.00, P = 0.002) for clear cell RCC. Furthermore, an elevated PC level was significantly associated with TNM stage (OR 3.11, 95% CI 1.59-6.06, P = 0.001), pathological T stage (OR 3.13, 95% CI 2.60-3.77, P<0.001), lymph node metastasis (OR 4.01, 95% CI 2.99-5.37, P<0.001), distant metastasis (OR 3.85, 95% CI 2.46-6.04, P<0.001), Fuhrman grade (OR 3.70, 95% CI 3.00-4.56, P<0.001), tumor size (OR 4.69, 95% CI 2.78-7.91, P<0.001) and Eastern Cooperative Oncology Group score (OR 5.50, 95% CI 3.26-9.28, P<0.001).ConclusionAn elevated PC level implied poor prognosis in patients with RCC and could serve as a readily available biomarker for managing this disease.     

Heat Stress Reduces Intestinal Barrier Integrity and Favors Intestinal Glucose Transport in Growing Pigs

Excessive heat exposure reduces intestinal integrity and post-absorptive energetics that can inhibit wellbeing and be fatal. Therefore, our objectives were to examine how acute heat stress (HS) alters intestinal integrity and metabolism in growing pigs. Animals were exposed to either thermal neutral (TN, 21°C; 35–50% humidity; n = 8) or HS conditions (35°C; 24–43% humidity; n = 8) for 24 h. Compared to TN, rectal temperatures in HS pigs increased by 1.6°C and respiration rates by 2-fold (P<0.05). As expected, HS decreased feed intake by 53% (P<0.05) and body weight (P<0.05) compared to TN pigs. Ileum heat shock protein 70 expression increased (P<0.05), while intestinal integrity was compromised in the HS pigs (ileum and colon TER decreased; P<0.05). Furthermore, HS increased serum endotoxin concentrations (P = 0.05). Intestinal permeability was accompanied by an increase in protein expression of myosin light chain kinase (P<0.05) and casein kinase II-α (P = 0.06). Protein expression of tight junction (TJ) proteins in the ileum revealed claudin 3 and occludin expression to be increased overall due to HS (P<0.05), while there were no differences in claudin 1 expression. Intestinal glucose transport and blood glucose were elevated due to HS (P<0.05). This was supported by increased ileum Na⁺/K⁺ ATPase activity in HS pigs. SGLT-1 protein expression was unaltered; however, HS increased ileal GLUT-2 protein expression (P = 0.06). Altogether, these data indicate that HS reduce intestinal integrity and increase intestinal stress and glucose transport.     

Decay of Fecal Indicator Bacterial Populations and Bovine-Associated Source-Tracking Markers in Freshly Deposited Cow Pats

Understanding the survival of fecal indicator bacteria (FIB) and microbial source-tracking (MST) markers is critical to developing pathogen fate and transport models. Although pathogen survival in water microcosms and manure-amended soils is well documented, little is known about their survival in intact cow pats deposited on pastures. We conducted a study to determine decay rates of fecal indicator bacteria (Escherichia coli and enterococci) and bovine-associated MST markers (CowM3, Rum-2-bac, and GenBac) in 18 freshly deposited cattle feces from three farms in northern Georgia. Samples were randomly assigned to shaded or unshaded treatment in order to determine the effects of sunlight, moisture, and temperature on decay rates. A general linear model (GLM) framework was used to determine decay rates. Shading significantly decreased the decay rate of the E. coli population (P < 0.0001), with a rate of −0.176 day⁻¹ for the shaded treatment and −0.297 day⁻¹ for the unshaded treatment. Shading had no significant effect on decay rates of enterococci, CowM3, Rum-2-bac, and GenBac (P > 0.05). In addition, E. coli populations showed a significant growth rate (0.881 day⁻¹) in the unshaded samples during the first 5 days after deposition. UV-B was the most important parameter explaining the decay rate of E. coli populations. A comparison of the decay behaviors among all markers indicated that enterococcus concentrations exhibit a better correlation with the MST markers than E. coli concentrations. Our results indicate that bovine-associated MST markers can survive in cow pats for at least 1 month after excretion, and although their decay dynamic differs from the decay dynamic of E. coli populations, they seem to be reliable markers to use in combination with enterococci to monitor fecal pollution from pasture lands.     

Combination of nitrogen deposition and ultraviolet-B radiation decreased litter decomposition in subtropical China

Aims

The interactive effects of enhanced nitrogen (N) deposition and ultraviolet-B (UV-B) radiation on litter decomposition are still unknown. The aims are to test whether the interactive effects of the two environmental factors on litter decomposition and nutrient loss are stronger than that of each factor alone.

Methods

Experiment included five treatments: elevated UV-B radiation (UV-B, 10 % enhancement), low N addition (N1, 30 kg N ha^?1 year^?1), high N addition (N2, 60 kg N ha^?1 year^?1), the two combined treatments of the two factors (UV-B+N1 and UV-B+N2), and an unmanipulated control.

Results

The annual decomposition rates under combination of UV-B and N addition significantly decreased compared with that under UV-B and N additions for Pinus massoniana, and did also compared with that under UV-B but did not significantly differ with N additions for Cyclobalanopsis glauca. Negative effects of N additions alone on lignin degradation and P loss were partly offset but negative effect on N loss was further amplified when was combined with UV-B.

Conclusions

The combination of N deposition and UV-B radiation on litter decomposition and nutrient loss was significantly different from that of each factor alone without a general response pattern of decomposition, and was regulated by litter chemistry.     

Differences in SOM Decomposition and Temperature Sensitivity among Soil Aggregate Size Classes in a Temperate Grasslands

The principle of enzyme kinetics suggests that the temperature sensitivity (Q₁₀) of soil organic matter (SOM) decomposition is inversely related to organic carbon (C) quality, i.e., the C quality-temperature (CQT) hypothesis. We tested this hypothesis by performing laboratory incubation experiments with bulk soil, macroaggregates (MA, 250–2000 μm), microaggregates (MI, 53–250 μm), and mineral fractions (MF, <53 μm) collected from an Inner Mongolian temperate grassland. The results showed that temperature and aggregate size significantly affected on SOM decomposition, with notable interactive effects (P<0.0001). For 2 weeks, the decomposition rates of bulk soil and soil aggregates increased with increasing incubation temperature in the following order: MA>MF>bulk soil >MI(P <0.05). The Q₁₀ values were highest for MA, followed (in decreasing order) by bulk soil, MF, and MI. Similarly, the activation energies (E_a) for MA, bulk soil, MF, and MI were 48.47, 33.26, 27.01, and 23.18 KJ mol⁻¹, respectively. The observed significant negative correlations between Q₁₀ and C quality index in bulk soil and soil aggregates (P<0.05) suggested that the CQT hypothesis is applicable to soil aggregates. Cumulative C emission differed significantly among aggregate size classes (P <0.0001), with the largest values occurring in MA (1101 μg g⁻¹), followed by MF (976 μg g⁻¹) and MI (879 μg g⁻¹). These findings suggest that feedback from SOM decomposition in response to changing temperature is closely associated withsoil aggregation and highlights the complex responses of ecosystem C budgets to future warming scenarios.     

The Intestinal Barrier in Irritable Bowel Syndrome: Subtype-Specific Effects of the Systemic Compartment in an In Vitro Model

BackgroundIrritable bowel syndrome (IBS) is a disorder with multifactorial pathophysiology. Intestinal barrier may be altered, especially in diarrhea-predominant IBS (IBS-D). Several mediators may contribute to increased intestinal permeability in IBS.AimWe aimed to assess effects of tryptase and LPS on in vitro permeability using a 3-dimensional cell model after basolateral cell exposure. Furthermore, we assessed the extent to which these mediators in IBS plasma play a role in intestinal barrier function.ResultsTryptase (20 and 50 mU) and LPS (6.25 – 50 ng/mL) significantly increased Caco-2 permeability versus control (all P< 0.05). Plasma of IBS-D only showed significantly elevated median tryptase concentrations (7.1 [3.9 – 11.0] vs. 4.2 [2.2 – 7.0] vs. 4.2 [2.5 – 5.9] μg/mL; P<0.05) and LPS concentrations (3.65 [3.00 – 6.10] vs. 3.10 [2.60-3.80] vs. 2.65 [2.40 – 3.40] EU/ml; P< 0.05) vs. IBS-C and HC. Also, plasma of IBS-D increased Caco-2 permeability versus HC (0.14450 ± 0.00472 vs. 0.00021 ± 0.00003; P < 0.001), which was attenuated by selective inhibition of tryptase and LPS (P< 0.05).ConclusionBasolateral exposure of spheroids to plasma of IBS-D patients resulted in a significantly increased FD4 permeation, which was partially abolished by selective inhibition of tryptase and LPS. These findings point to a role of systemic tryptase and LPS in the epithelial barrier alterations observed in patients with IBS-D.     

The direct effects of UV-B radiation on Betula pubescens litter decomposing at four European field sites

A co-ordinated series of field experiments were conducted to consider the effects of elevated UV-B radiation applied directly to decomposing plant litter. Betula pubescens was decomposed under ambient and elevated UV-B (simulating a 15% ozone depletion) using outdoor irradiation facilities at Adventdalen, Norway (78° N), Abisko, Sweden (68° N), Amsterdam, The Netherlands (52° N,) and Patras, Greece (38° N). There was no significant effect of treatment on mass loss for samples collected after 2, 12 and 14 months decomposition at Amsterdam, or after 4 months decomposition at Adventdalen. Significant reductions in the mass loss of litter decomposing under elevated UV-B compared to ambient were found at the other 2 sites. The only effect of treatment on litter chemistry during decomposition was a significant reduction in the N concentration of material at Abisko and a significant increase in C:N at Patras for litter decomposing under elevated UV-B. Significant differences were found in the structure of the fungal community decomposing litter in Sweden, the only site to be tested. These data, and the few published studies of the response of decomposition to UV-B incident on litter suggest that, in the ecosystems and climates that have been studied, such direct effects are typically confined to the initial stages of decomposition, and are rather small in magnitude.     

Osmoregulatory Responses of Fungi Inhabiting Standing Litter of the Freshwater Emergent Macrophyte Juncus effusus

Standing litter of emergent macrophytes often forms a major portion of the detrital mass in wetland habitats. Microbial assemblages inhabiting this detritus must adapt physiologically to daily fluctuations in temperature and water availability. We examined the effects of various environmental conditions on the concentrations of osmoregulatory solutes (polyols and trehalose) and the respiratory activities of fungal assemblages inhabiting standing litter of the freshwater emergent macrophyte Juncus effusus. Under field conditions, the concentrations of osmolytes (polyols plus trehalose) in fungal decomposers were negatively correlated with plant litter water potentials (r = −0.75, P < 0.001) and rates of microbial respiration (r = −0.66, P < 0.001). The highest concentration of osmolytes (polyols plus trehalose) occurred in standing litter exposed to desiccating conditions (range from wet to dry, 0.06 to 0.68 μmol · mg of fungal biomass⁻¹). Similar fluctuations in polyol and trehalose concentrations were observed in standing litter wetted and dried under laboratory conditions and for four predominant fungal decomposers of J. effusus grown individually on sterilized Juncus leaves. These studies suggest that fungal inhabitants associated with standing litter of emergent macrophytes can adjust their intracellular solute concentrations in response to daily fluctuations in water availability.     

The Effects of Di-(2-ethylhexyl)-phthalate Exposure on Fertilization and Embryonic Development In Vitro and Testicular Genomic Mutation In Vivo

The present study was undertaken to determine the reproductive hazards of Di-(2-ethylhexyl)-phthalate (DEHP) on mouse spermatozoa and embryos in vitro and genomic changes in vivo. Direct low-level DEHP exposure (1 μg/ml) on spermatozoa and embryos was investigated by in vitro fertilization (IVF) process, culture of preimplanted embryos in DEHP-supplemented medium and embryo transfer to achieve full term development. Big Blue® transgenic mouse model was employed to evaluate the mutagenesis of testicular genome with in vivo exposure concentration of DEHP (500 mg/kg/day). Generally, DEHP-treated spermatozoa (1 μg/ml, 30 min) presented reduced fertilization ability (P<0.05) and the resultant embryos had decreased developmental potential compared to DMSO controls (P<0.05). Meanwhile, the transferred 2-cell stage embryos derived from treated spermatozoa also exhibited decreased birth rate than that of control (P<0.05). When fertilized oocytes or 2-cell stage embryos were recovered by in vivo fertilization (without treatment) and then exposed to DEHP, the subsequent development proceed to blastocysts was different, fertilized oocytes were significantly affected (P<0.05) whereas developmental progression of 2-cell stage embryos was similar to controls (P>0.05). Testes of the Big Blue® transgenic mice treated with DEHP for 4 weeks indicated an approximately 3-fold increase in genomic DNA mutation frequency compared with controls (P<0.05). These findings unveiled the hazardous effects of direct low-level exposure of DEHP on spermatozoa''s fertilization ability as well as embryonic development, and proved that in vivo DEHP exposure posed mutagenic risks in the reproductive organ – at least in testes, are of great concern to human male reproductive health.     

Construction and evaluation of the novel DNA vaccine harboring the inhibin α (1–32) and the RF-amide related peptide-3 genes for improving fertility in mice

To further improve fertility of animals, a novel gene RFRP-3 (RF-amide related peptide-3, RFRP-3) was used to construct DNA vaccines with INH α (1–32) (inhibin, INH) fragment for the first time. The aim of this study was to evaluate the effects of novel DNA vaccines on fertility in mice. Synthesized SINH and SRFRP (INH and RFRP genes were separately ligated to the C-terminus of the small envelope protein of the hepatitis B virus (HBV-S) gene) fragments were inserted into multiple cloning site of pIRES vector to develop p-SINH/SRFRP. The synthesized tissue plasminogen activator (TPA) signal sequence was then inserted into the p-SINH/SRFRP to construct p-TPA-SINH/TPA-SFRFP. Meanwhile, p-SINH was prepared and considered as positive control. Forty Kunming mice were equally divided into four groups and respectively immunized by electroporation with p-SINH, p-SINH/SRFRP and p-TPA-SINH/TPA-SRFRP vaccine (three times at 2 weeks interval) and saline as control. Results showed that the average antibodies (P/N value) of anti-INH and anti-RFRP in mice inoculated with p-TPA-SINH/TPA-SFRFP were significantly higher (P<0.05) than those inoculated with p-SINH/SRFRP and the positive rates were 100% (anti-INH) and 90% (anti-RFRP) respectively, at 2 weeks after the third immunization. Litter size of mice immunized with the three recombinant plasmids was higher (P<0.05) than that of the control, and litter size of mice immunized with p-TPA-SINH/TPA-SRFRP significantly increased (P<0.05) compared with p-SINH. These results suggested that the p-TPA-SINH/TPA-SRFRP harboring INH and RFRP genes was successfully constructed and had good immunogenicity, and might effectively increase litter size.     

The Effect of Leaf Litter Cover on Surface Runoff and Soil Erosion in Northern China

The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter), four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (p<0.05). Average runoff yield was 29.5% and 31.3% less than bare-soil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, p<0.05), and the efficiency in runoff reduction by litter decreased considerably. Runoff yield and the runoff coefficient increased dramatically by 72.9 and 5.4 times, respectively. The period of time before runoff appeared decreased approximately 96.7% when rainfall intensity increased from 5.7 to 75.6 mm h⁻¹. Broadleaf and needle leaf litter showed similarly relevant effects on runoff and soil erosion control, since no significant differences (p≤0.05) were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (p<0.05) with sediment yield. These results suggest that the protective role of leaf litter in runoff and erosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.     

Correlations of MTHFR 677C>T Polymorphism with Cardiovascular Disease in Patients with End-Stage Renal Disease: A Meta-Analysis

ObjectiveThis meta-analysis was conducted to evaluate the correlations of a common polymorphism (677C>T) in the methylenetetrahydrofolate reductase (MTHFR) gene with risk of cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD).MethodThe following electronic databases were searched without language restrictions: Web of Science (1945∼2013), the Cochrane Library Database (Issue 12, 2013), MEDLINE (1966∼2013), EMBASE (1980∼2013), CINAHL (1982∼2013) and the Chinese Biomedical Database (CBM) (1982∼2013). Meta-analysis was performed using STATA statistical software. Odds ratios (ORs) with their 95% confidence intervals (95%CIs) were calculated.ResultsEight cohort studies met all inclusion criteria and were included in this meta-analysis. A total of 2,292 ESRD patients with CVD were involved in this meta-analysis. Our meta-analysis results revealed that the MTHFR 677C>T polymorphism might increase the risk of CVD in ESRD patients (TT vs. CC: OR = 2.75, 95%CI = 1.35∼5.59, P = 0.005; CT+TT vs. CC: OR = 1.39, 95%CI = 1.09∼1.78, P = 0.008; TT vs. CC+CT: OR = 2.52, 95%CI = 1.25∼5.09, P = 0.010; respectively). Further subgroup analysis by ethnicity suggested that the MTHFR 677C>T polymorphism was associated with an elevated risk for CVD in ESRD patients among Asians (TT vs. CC: OR = 3.38, 95%CI = 1.11∼10.28, P = 0.032; CT+TT vs. CC: OR = 1.44, 95%CI = 1.05∼1.97, P = 0.022; TT vs. CC+CT: OR = 3.15, 95%CI = 1.02∼9.72, P = 0.046; respectively), but not among Africans or Caucasians (all P>0.05).ConclusionOur findings indicate that the MTHFR 677C>T polymorphism may be associated with an elevated risk for CVD in ESRD patients, especially among Asians.     

Prognostic significance of lncRNA DANCR expression in human cancers: a systematic review and meta-analysis

Several studies demonstrated that lncRNA differentiation antagonizing non-protein coding RNA (lncRNA DANCR) expression might have the potential capacity to predict the cancer prognosis; however, definite conclusion has not been obtained. The aim of this meta-analysis was to evaluate the prognostic value of lncRNA DANCR expression in cancers. PubMed, Web of Science, Scopus, and Embase were comprehensively searched for relevant studies. Studies meeting all inclusion standards were included into this meta-analysis. The analysis of overall survival (OS), disease-free survival (DFS), or clinicopathological features was conducted. Total 11 studies containing 1154 cancer patients were analyzed in this meta-analysis. The results showed, compared with low lncRNA DANCR expression, high lncRNA DANCR expression was significantly associated with shorter OS (hazard ratio [HR] = 1.85; 95% CI = 1.52–2.26; P<0.01) and DFS (HR = 1.82; 95% CI = 1.43–2.32; P<0.01) in cancers. Besides, high lncRNA DANCR expression predicted deeper tumor invasion (P<0.01), earlier lymph node metastasis (P<0.01), earlier distant metastasis (P<0.01), and more advanced clinical stage (P<0.01) compared with low lncRNA DANCR expression in cancer populations. High lncRNA DANCR expression was associated with worse prognosis compared with low lncRNA DANCR expression in cancers. LncRNA DANCR expression could serve as a prognostic factor of human cancers.