Angiotensin‐Converting Enzyme Inhibition and Angiotensin AT1 Receptor Blockade Downregulate Angiotensin‐Converting Enzyme Expression and Attenuate Renal Injury in Streptozotocin‐Induced Diabetic Rats

Angiotensin‐converting enzyme (ACE) is upregulated in the diabetic kidney and contributes to renal injury. This study investigates the possible beneficial effects of the ACE inhibitor (ACEI), enalapril and the AT1 receptor blocker (ARB), valsartan, on renal ACE expression, renal structure, and function in streptozotocin (STZ)‐induced diabetic rats. Male Wistar rats were allocated into four groups: control, STZ‐diabetic rats, and STZ‐diabetic rats treated with either enalapril (10 mg/kg/day) or valsartan (50 mg/kg/day) for 8 weeks. Enalapril and valsartan reduced renal ACE mRNA and protein expression, Na⁺/K⁺‐ATPase activity, oxidative stress, and serum transforming growth factor‐β1 levels compared to the diabetic group. Both treatments normalized renal nitrate/nitrite levels and ameliorated the observed histopathological changes. In conclusion, ACE downregulation by ACEI and ARB indicates that angiotensin II upregulates ACE through AT1 receptor. Prevention of diabetes‐induced changes in ACE expression and Na⁺/K⁺‐ATPase activity could be a new explanation of the renoprotective effects of ACEIs and ARBs. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:378‐387, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21500     

Measurement of net ecosystem exchange,productivity and respiration in three spruce forests in Sweden shows unexpectedly large soil carbon losses

Measurement of net ecosystem exchange was made using the eddy covariance method above three forests along a north-south climatic gradient in Sweden: Flakaliden in the north, Knottåsen in central and Asa in south Sweden. Data were obtained for 2 years at Flakaliden and Knottåsen and for one year at Asa. The net fluxes (N_ep) were separated into their main components, total ecosystem respiration (R_t) and gross primary productivity (P_g). The maximum half-hourly net uptake during the heart of the growing season was highest in the southernmost site with ?0.787 mg CO₂ m^?2 s^?1 followed by Knottåsen with ?0.631 mg CO₂ m^?2 s^?1 and Flakaliden with ?0.429 mg CO₂ m^?2 s^?1. The maximum respiration rates during the summer were highest in Knottåsen with 0.245 mg CO₂ m^?2 s^?1 while it was similar at the two other sites with 0.183 mg CO₂ m^?2 s^?1. The annual N_ep ranged between uptake of ?304 g C m^?2 year^?1 (Asa) and emission of 84 g C m^?2 year^?1 (Knottåsen). The annual R_t and P_g ranged between 793 to 1253 g C m^?2 year^?1 and ?875 to ?1317 g C m^?2 year^?1, respectively. Biomass increment measurements in the footprint area of the towers in combination with the measured net ecosystem productivity were used to estimate the changes in soil carbon and it was found that the soils were losing on average 96–125 g C m^?2 year^?1. The most plausible explanation for these losses was that the studied years were much warmer than normal causing larger respiratory losses. The comparison of net primary productivity and P_g showed that ca 60% of P_g was utilized for autotrophic respiration.     

Effects of Supplemental Copper on the Serum Lipid Profile,Meat Quality,and Carcass Composition of Goat Kids

To evaluate the effects of copper (Cu) supplementation on the serum lipid profile, meat quality, and carcass composition of goat kids, thirty-five 3–4-month-old Jian Yang big-eared goat kids (BW 20.3?±?0.6 kg) were randomly assigned to one of seven dietary Cu treatments (n?=?5/treatment). The dietary Cu concentrations were: (1) control (no supplemental Cu), (2) 20 mg, (3) 40 mg, (4) 80 mg, (5) 160 mg, (6) 320 mg, and (7) 640 mg of supplemental Cu/kg dry matter (DM). Copper was supplemented as CuSO₄.5H₂O (25.2 % Cu). The goats were fed a high-concentrate basal diet with the different concentrations of supplemental Cu/kg DM for 96 days. The serum lipid profile was determined on day 51 and day 96. Meat quality and carcass composition of longissimus dorsi muscle were measured after the goats were slaughtered at 96 days. Serum total cholesterol, triglycerides, high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C) were not affected by treatment (P?>?0.18). No differences were observed in drip loss, cooking loss, a* (redness/greenness) and b* (yellowness/blueness) values (P?>?0.17); however, the 24-h pH value (linear; P?=?0.0009) and L* (brightness) value (linear; P?=?0.0128) decreased, and shear force increased (linear; P?=?0.0005) as Cu supplementation increased. The intramuscular fat (%) increased (linear; P?=?0.001) as supplemental Cu increased. No differences (P?>?0.21) in the moisture, crude protein, and ash (%) were observed. Results of this study indicate that supplemental Cu does not modify the serum lipid profile; however, it can impact intramuscular fat content and the meat quality of goat kids.     

Short-term simulated nitrogen deposition increases carbon sequestration in a Pleioblastus amarus plantation

In order to understand the influence of nitrogen (N) deposition on the key processes relevant to the carbon (C) balance in a bamboo plantation, a two-year field experiment involving the simulated deposition of N in a Pleioblastus amarus plantation was conducted in the rainy region of SW China. Four levels of N treatments: control (no N added), low-N (50 kg N ha^?1 year^?1), medium-N (150 kg N ha^?1 year^?1), and high-N (300 kg N ha^?1 year^?1) were set in the present study. The results showed that soil respiration followed a clear seasonal pattern, with the maximum rates in mid-summer and the minimum in late winter. The annual cumulative soil respiration was 585?±?43 g CO₂-C m^?2 year^?1 in the control plots. Simulated N deposition significantly increased the mean annual soil respiration rate, fine root biomass, soil microbial biomass C (MBC), and N concentration in fine roots and fresh leaf litter. Soil respirations exhibited a positive exponential relationship with soil temperature, and a linear relationship with MBC. The net primary production (NPP) ranged from 10.95 to 15.01 Mg C ha^?1 year^?1 and was higher than the annual soil respiration (5.85 to 7.62 Mg C ha^?1 year^?1) in all treatments. Simulated N deposition increased the net ecosystem production (NEP), and there was a significant difference between the control and high N treatment NEP, whereas, the difference of NEP among control, low-N, and medium-N was not significant. Results suggest that N controlled the primary production in this bamboo plantation ecosystem. Simulated N deposition increased the C sequestration of the P. amarus plantation ecosystem through increasing the plant C pool, though CO₂ emission through soil respiration was also enhanced.     

Combined angiotensin receptor blocker and ACE inhibitor on myocardial fibrosis and left ventricular stiffness in dogs with heart failure

Angiotensin receptor blocker (ARB) and angiotensin-converting enzyme (ACE) inhibitor (ACEI) each act in a different manner to prevent myocardial fibrosis and left ventricular (LV) stiffness in animals with pathways in the heart for generating ANG II as well as ACE. A model of pacing-induced congestive heart failure (CHF) was used to test the central hypothesis that ARB + ACEI prevents myocardial fibrosis and decreases LV stiffness to a greater extent than ARB or ACEI alone. Thirty-five dogs were assigned to the following treatment protocols on the 8th day of a 4-wk pacing schedule: 1) rapid ventricular pacing, 2) ARB (candesartan cilexetil, 1.5 mg.kg(-1).day(-1)) with pacing, 3) ACEI (enalapril, 1.9 mg.kg(-1).day(-1)) with pacing, 4) ARB (candesartan cilexetil, 0.75 mg.kg(-1).day(-1)) + ACEI (enalapril, 0.95 mg.kg(-1).day(-1)) with pacing, and 5) sham operation. The LV stiffness coefficient was significantly increased after rapid pacing but was significantly lower with ARB + ACEI than with ARB or ACEI alone. The collagen volume fraction and mRNA levels of collagen I and III, which were increased by rapid pacing, were significantly lower with ARB + ACEI than with ARB or ACEI alone. Thus ARB + ACEI prevents myocardial fibrosis and decreases LV stiffness during the progression of CHF compared with ARB or ACEI alone.     

Carbon cycling and sequestration in a Japanese red pine (Pinus densiflora) forest on lava flow of Mt. Fuji

Biometric-based carbon flux measurements were conducted in a pine forest on lava flow of Mt. Fuji, Japan, in order to estimate carbon cycling and sequestration. The forest consists mainly of Japanese red pine (Pinus densiflora) in a canopy layer and Japanese holly (Ilex pedunculosa) in a subtree layer. The lava remains exposed on the ground surface, and the soil on the lava flow is still immature with no mineral soil layer. The results showed that the net primary production (NPP) of the forest was 7.3 ± 0.7 t C ha^?1 year^?1, of which 1.4 ± 0.4 t C ha^?1 year^?1 was partitioned to biomass increment, 3.2 ± 0.5 t C ha^?1 year^?1 to above-ground fine litter production, 1.9 t C ha^?1 year^?1 to fine root production, and 0.8 ± 0.2 t C ha^?1 year^?1 to coarse woody debris. The total amount of annual soil surface CO₂ efflux was estimated as 6.1 ± 2.9 t C ha^?1 year^?1, using a closed chamber method. The estimated decomposition rate of soil organic matter, which subtracted annual root respiration from soil respiration, was 4.2 ± 3.1 t C ha^?1 year^?1. Biometric-based net ecosystem production (NEP) in the pine forest was estimated at 2.9 ± 3.2 t C ha^?1 year^?1, with high uncertainty due mainly to the model estimation error of annual soil respiration and root respiration. The sequestered carbon being allocated in roughly equal amounts to living biomass (1.4 t C ha^?1 year^?1) and the non-living C pool (1.5 t C ha^?1 year^?1). Our estimate of biometric-based NEP was 25 % lower than the eddy covariance-based NEP in this pine forest, due partly to the underestimation of NPP and difficulty of estimation of soil and root respiration in the pine forest on lava flows that have large heterogeneity of soil depth. However, our results indicate that the mature pine forest acted as a significant carbon sink even when established on lava flow with low nutrient content in immature soils, and that sequestration strength, both in biomass and in soil organic matter, is large.     

Effect of nitrogen and phosphorus fertilization on the composition of rhizobacterial communities of two Chilean Andisol pastures

The effect of nitrogen (N) and phosphorus (P) fertilization on composition of rhizobacterial communities of volcanic soils (Andisols) from southern Chile at molecular level is poorly understood. This paper investigates the composition of rhizobacterial communities of two Andisols under pasture after 1- and 6-year applications of N (urea) and P (triple superphosphate). Soil samples were collected from two previously established sites and the composition of rhizobacterial communities was determined by denaturing gradient gel electrophoresis (PCR–DGGE). The difference in the composition and diversity between rhizobacterial communities was assessed by nonmetric multidimensional scaling (MDS) analysis and the Shannon–Wiener index. In Site 1 (fertilized for 1 year), PCR–DGGE targeting 16S rRNA genes and MDS analysis showed that moderate N application (270 kg N ha^?1 year^?1) without P significantly changed the composition of rhizobacterial communities. However, no significant community changes were observed with P (240 kg P ha^?1 year^?1) and N–P application (270 kg N ha^?1 year^?1 plus 240 kg P ha^?1 year^?1). In Site 2 (fertilized for 6 years with P; 400 kg P ha^?1 year^?1), PCR–DGGE targeting rpoB, nifH, amoA and alkaline phosphatase genes and MDS analysis showed changes in rhizobacterial communities only at the highest rate of N application (600 kg N ha^?1 year^?1). Quantitative PCR targeting 16S rRNA genes also showed higher abundance of bacteria at higher N application. In samples from both sites, the Shannon–Wiener index did not show significant difference in the diversity of rhizobacterial communities. The changes observed in rhizobacterial communities coincide in N fertilized pastures with lower soil pH and higher pasture yields. This study indicates that N–P application affects the soil bacterial populations at molecular level and needs to be considered when developing fertilizer practices for Chilean pastoral Andisols.     

Screening Perennial Warm-Season Bioenergy Crops as an Alternative for Phytoremediation of Excess Soil P

A recent alternative strategy to reduce environmental problems associated with P transport from agricultural soils is the use of bioenergy crops to remediate excess soil P. In addition to the positive impacts associated with P mitigation, harvested biomass used as a renewable energy source can also offset the cost associated with plant-based P remediation strategies. The objective of this study was to identify potential crop species that can be used for remediation of soil P and as a cellulosic feedstock for production of renewable energy in South Florida. Fifteen crop entries were investigated for their potential to remove P from a P-enriched soil. Dry matter (DM) yield varied among crop species with greatest yield observed for elephantgrass (Pennisetum purpureum Schum.) and sugarcane (Saccharum spp.) (43 and 39 Mg?ha^?1 year^?1, respectively). Similarly, greater P removal rates were observed for elephantgrass (up to 126 kg?P?ha^?1 year^?1 in 2008) followed by sugarcane (62 kg?P?ha^?1 year^?1 in 2008). Although there was no effect (P?=?0.45) of crop species on P reduction in the soil, soil P concentrations decreased linearly during the 3-year study. Because of its relatively greater DM yield and P removal rates, elephantgrass was shown to be a good candidate for remediation of excess soil P in South Florida Spodosols.     

Role of coarse woody debris in the carbon cycle of Takayama forest,central Japan

Coarse woody debris (CWD) is an important component of the forest carbon cycle, acting as a carbon pool and a source of CO₂ in temperate forest ecosystems. We used a soda-lime closed-chamber method to measure CO₂ efflux from downed CWD (diameter ≥5 cm) and to examine CWD respiration (R _CWD) under field conditions over 1 year in a temperate secondary pioneer forest in Takayama forest. We also investigated tree mortality (input to the CWD pool) from the data obtained from the annual tree census, which commenced in 2000. We developed an exponential function of temperature to predict R _CWD in each decay class (R ² = 0.81–0.97). The sensitivity of R _CWD to changing temperature, expressed as Q ₁₀, ranged from 2.12 to 2.92 and was relatively high in decay class III. Annual C flux from CWD (F _CWD) was extrapolated using continuous air temperature measurements and CWD necromass pools in the three decay classes. F _CWD was 3.0 (class I), 17.8 (class II), and 13.7 g C m^?2 year^?1 (class III) and totaled 34 g C m^?2 year^?1 in 2009. Annual input to CWD averaged 77 g C m^?2 year^?1 from 2000 to 2009. The budget of the CWD pool in the Takayama forest, including tree mortality inputs and respiratory outputs, was 0.43 Mg C ha^?1 year^?1 (net C sink) owing to high tree mortality in the mature pioneer forest. The potential CWD sink is important for the carbon cycle in temperate successional forests.     

A multi-environmental study of recent breeding progress on nitrogen use efficiency in wheat (Triticum aestivum L.)

Key message

By comparing 195 varieties in eight trials, this study assesses nitrogen use efficiency improvement in high and low nitrogen conditions in European winter wheat over the last 25 years.

Abstract

In a context where European agriculture practices have to deal with environmental concerns and nitrogen (N) fertiliser cost, nitrogen use efficiency (NUE) has to be improved. This study assessed genetic progress in winter wheat (Triticum aestivum L.) NUE. Two hundred and twenty-five European elite varieties were tested in four environments under two levels of N. Global genetic progress was assessed on additive genetic values and on genotype × N interaction, covering 25 years of European breeding. To avoid sampling bias, quality, precocity and plant height were added as covariates in the analyses when needed. Genotype × environment interactions were highly significant for all the traits studied to such an extent that no additive genetic effect was detected on N uptake. Genotype × N interactions were significant for yield, grain protein content (GPC), N concentration in straw, N utilisation, and NUE. Grain yield improvement (+0.45 % year^?1) was independent of the N treatment. GPC was stable, thus grain nitrogen yield was improved (+0.39 % year^?1). Genetic progress on N harvest index (+0.12 % year^?1) and on N concentration in straw (?0.52 % year^?1) possibly revealed improvement in N remobilisation. There has been an improvement of NUE additive genetic value (+0.33 % year^?1) linked to better N utilisation (+0.20 % year^?1). Improved yield stability was detected as a significant improvement of NUE in low compared to high N conditions. The application of these results to breeding programs is discussed.     

Efficacy and safety of Abelmoschus manihot for IgA nephropathy: A multicenter randomized clinical trial

Rationale and ObjectiveIgA nephropathy (IgAN) is an important cause for end-stage renal disease worldwide. The treatment for IgAN remains challenging, and few randomized and controlled clinical trials have been conducted to evaluate new therapies. The present study assesses the efficacy and safety of Abelmoschus manihot (AM) in IgAN patients.Study DesignRandomized, non-inferiority, double-blind, double-dummy multicenter trial.Setting and ParticipantsThis trial was designed to recruit 1,600 biopsy-proven IgAN patients (proteinuria between 0.5-3.0 g/d and estimated glomerular filtration rate [eGFR] of ≥ 45 ml/min/1.73 m²) across China.InterventionsThe participants were randomized at 1:1 to AM (2.5 g for three times per day) or losartan potassium (100 mg per day) for 48 weeks.OutcomesThe primary outcome was the change in 24-hour proteinuria from baseline to week 48. The secondary outcomes were the change in eGFR from baseline to week 48, and the incidents of endpoint events (proteinuria ≥ 3.5 g/24 h, doubling of serum creatinine, or receiving renal replacement treatment).ResultsAmong 1,470 randomized patients (mean age, 37.4 [SD, 10.6] years old; 777 [52.9%] were female; mean eGFR, 95.0 [SD, 24.3] mL/min/1.73 m²; mean 24-hour proteinuria, 1.2 [SD, 0.7] g/d), the mean decline in 24-h proteinuria at week 48 was 230 mg and 253 mg in the AM and losartan potassium groups, respectively (P = 0.676). The mean difference in the change in 24-h proteinuria between these two groups was -23.32 mg (95% confident interval: -123.2 to 76.6, p = 0.647). The mean decline in eGFR was 0.41 ml/min/1.73 m² and 0.76 ml/min/1.73 m² in the AM and losartan potassium groups, respectively (p = 0.661). The mean difference in the change in eGFR between these two groups was -0.43 ml/min/1.73 m² (95% confident interval: -1.99 to 1.13, p = 0.589). The incidence of endpoint events was 8.6% in the AM group and 8.2% in the losartan group (p = 0.851).LimitationsThe results of the trial may not be generalized to IgAN patients with a proteinuria of > 3.0 g/d and an eGFR of < 45 ml/min/1.73 m². The long-term benefits of AM in reducing the risk of progressive renal dysfunction remains unclear, based on this 48-week observation.ConclusionAM can be recommended as a promising treatment for IgAN patients.     

Soil Carbon Storage by Switchgrass Grown for Bioenergy

Life-cycle assessments (LCAs) of switchgrass (Panicum virgatum L.) grown for bioenergy production require data on soil organic carbon (SOC) change and harvested C yields to accurately estimate net greenhouse gas (GHG) emissions. To date, nearly all information on SOC change under switchgrass has been based on modeled assumptions or small plot research, both of which do not take into account spatial variability within or across sites for an agro-ecoregion. To address this need, we measured change in SOC and harvested C yield for switchgrass fields on ten farms in the central and northern Great Plains, USA (930 km latitudinal range). Change in SOC was determined by collecting multiple soil samples in transects across the fields prior to planting switchgrass and again 5 years later after switchgrass had been grown and managed as a bioenergy crop. Harvested aboveground C averaged 2.5?±?0.7 Mg C ha^?1 over the 5 year study. Across sites, SOC increased significantly at 0–30 cm (P?=?0.03) and 0–120 cm (P?=?0.07), with accrual rates of 1.1 and 2.9 Mg C ha^?1 year^?1 (4.0 and 10.6 Mg CO₂ ha^?1 year^?1), respectively. Change in SOC across sites varied considerably, however, ranging from ?0.6 to 4.3 Mg C ha^?1 year^?1 for the 0–30 cm depth. Such variation in SOC change must be taken into consideration in LCAs. Net GHG emissions from bioenergy crops vary in space and time. Such variation, coupled with an increased reliance on agriculture for energy production, underscores the need for long-term environmental monitoring sites in major agro-ecoregions.     

Preliminary findings on the influence of FTO rs9939609 and MC4R rs17782313 polymorphisms on resting energy expenditure,leptin and thyrotropin levels in obese non-morbid premenopausal women

Given that leptin, ghrelin and thyrotropin play a major role in the regulation of resting energy expenditure (REE) and that the FTO rs9939609 and the MC4R rs17782313 polymorphisms have been proposed to affect energy homeostasis, we hypothesized that both polymorphisms are associated with REE and that these relationships can be mediated by leptin, ghrelin and thyrotropin in obesity. Therefore, the present study aimed to examine the relationships between FTO rs9939609 and the MC4R rs17782313 with REE, leptin, ghrelin and thyrotropin levels in obese women. The study comprised 77 obese (body mass index 34.0?±?2.8 kg/m²) women (age 36.7?±?7 years). We measured body composition by dual-energy X-ray absorptiometry and REE by indirect calorimetry. We analysed fasting leptin, ghrelin and thyrotropin levels and the ratio of leptin to fat mass was calculated. Genotype distributions of the polymorphisms did not deviate from Hardy–Weinberg expectations (P values >0.2). Women carrying the A allele of the FTO rs9939609 had lower REE (1,580?±?22 vs. 1,739?±?35 kcal/day, P?<?0.001) and higher leptin to fat mass ratio (1.33?±?0.05 vs. 1.13?±?0.08 ng/ml kg, P?<?0.05) and thyrotropin levels (1.93?±?0.10 vs. 1.53?±?0.16 μU/ml, P?<?0.05) regardless of age and body mass index. We found no significant influence of the MC4R rs17782313 on energy metabolism or biochemical variables. Our findings confirm that the A allele of the FTO rs9939609 is associated with lower REE and increased plasma leptin levels. We also found an association between the FTO rs9939609 and thyrotropin, suggesting the possible influence of FTO in the hypothalamic–pituitary–thyroid axis as a potential mechanism of the increased adiposity.     

Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest

Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004–2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha^?1 year^?1, including below-ground coarse roots; this was partitioned into 2.5 tC ha^?1 year^?1 biomass increment, 1.6 tC ha^?1 year^?1 foliage litter, and 1.0 tC ha^?1 year^?1 other woody detritus. The total amount of annual soil surface CO₂ efflux was 6.8 tC ha^?1 year^?1, which included root respiration (1.9 tC ha^?1 year^?1) and heterotrophic respiration (RH) from soils (4.9 tC ha^?1 year^?1). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (?1.6 tC ha^?1 year^?1), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha^?1 year^?1) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.     

Fine-root seasonal pattern,production and turnover rate of European beech (Fagus sylvatica L.) stands in Italy Prealps: Possible implications of coppice conversion to high forest

Abstract

The aim of this study was to investigate the possible effects of coppice conversion to high forest on the beech fine-root systems. We compared the seasonal pattern of live and dead fine-root mass (d < 2 mm), production and turnover in three beech stands that differed in management practices. Tree density was higher in the 40-year-old coppice stand than in the stands that were converted from coppice to high forest in 1994 and 2004, respectively. We found that a reduction in tree density reduced the total fine-root biomass (Coppice stand, 353.8 g m^?2; Conversion 1994 stand, 203.6 g m^?2; Conversion 2004 stand, 176.2 g m^?2) which continued to be characterised by a bimodal pattern with two major peaks, one in spring and one in early fall. Conversion to high forest may also affect the fine-root soil depth distribution. Both fine-root production and turnover rate were sensitive to management practices. They were lower in the Coppice stand (production 131.5 g m^?2 year^?1; turnover rate 0.41 year^?1) than in the converted stands (1994 Conversion stand: production 232 g m^?2 year^?1, turnover rate 1.06 year^?1; 2004 Conversion stand: production 164.2 g m^?2 year^?1, turnover rate 0.79 year^?1).     

Net ecosystem carbon exchange and the greenhouse gas balance of tidal marshes along an estuarine salinity gradient

Tidal wetlands are productive ecosystems with the capacity to sequester large amounts of carbon (C), but we know relatively little about the impact of climate change on wetland C cycling in lower salinity (oligohaline and tidal freshwater) coastal marshes. In this study we assessed plant production, C cycling and sequestration, and microbial organic matter mineralization at tidal freshwater, oligohaline, and salt marsh sites along the salinity gradient in the Delaware River Estuary over four years. We measured aboveground plant biomass, carbon dioxide (CO₂) and methane (CH₄) exchange between the marsh and atmosphere, microbial sulfate reduction and methanogenesis in marsh soils, soil biogeochemistry, and C sequestration with radiodating of soils. A simple model was constructed to estimate monthly and annually integrated rates of gross ecosystem production (GEP), ecosystem respiration (ER) to carbon dioxide ( \( {\text{ER}}_{{{\text{CO}}_{2} }} \) ) or methane ( \( {\text{ER}}_{{{\text{CH}}_{4} }} \) ), net ecosystem production (NEP), the contribution of sulfate reduction and methanogenesis to ER, and the greenhouse gas (GHG) source or sink status of the wetland for 2 years (2007 and 2008). All three marsh types were highly productive but evidenced different patterns of C sequestration and GHG source/sink status. The contribution of sulfate reduction to total ER increased along the salinity gradient from tidal freshwater to salt marsh. The Spartina alterniflora dominated salt marsh was a C sink as indicated by both NEP (~140 g C m^?2 year^?1) and ²¹⁰Pb radiodating (336 g C m^?2 year^?1), a minor sink for atmospheric CH₄, and a GHG sink (~620 g CO_2-eq m^?2 year^?1). The tidal freshwater marsh was a source of CH₄ to the atmosphere (~22 g C–CH₄ m^?2 year^?1). There were large interannual differences in plant production and therefore C and GHG source/sink status at the tidal freshwater marsh, though ²¹⁰Pb radiodating indicated modest C accretion (110 g C m^?2 year^?1). The oligohaline marsh site experienced seasonal saltwater intrusion in the late summer and fall (up to 10 mS cm^?1) and the Zizania aquatica monoculture at this site responded with sharp declines in biomass and GEP in late summer. Salinity intrusion was also linked to large effluxes of CH₄ at the oligohaline site (>80 g C–CH₄ m^?2 year^?1), making this site a significant GHG source (>2,000 g CO_2-eq m^?2 year^?1). The oligohaline site did not accumulate C over the 2 year study period, though ²¹⁰Pb dating indicated long term C accumulation (250 g C m^?2 year^?1), suggesting seasonal salt-water intrusion can significantly alter C cycling and GHG exchange dynamics in tidal marsh ecosystems.     

Leaf and flower formation in shoot tips of mangrove trees in Pernambuco, Brazil

Leaves are major components of mangrove productivity, but data on leaf dynamics are scarce. We marked the shoot tips of three species in four sites of a riverine mangrove and monitored leaf formation, senescence and abscission and flower formation. The leaf area and biomass in the mangrove were estimated using phytosociological data. Leaf size and formation were similar among the four sites. The tips of Rhizophora mangle had more leaf scars (41), more leaves present (9.7), a faster leaf formation rate (one every 26 days) and a shorter life span (8.4 months) than those of Avicennia schaueriana (10, 8.1, 48 days and 13.1 months, respectively) and Laguncularia racemosa, except for the shorter life span (15, 6.6, 31 days and 6.8 months, respectively). The proportion of tips that flowered was higher in L. racemosa (13 %) and in R. mangle (11 %) than in A. schaueriana (2 %). The largest biomass of the average R. mangle leaf (0.75 vs. 0.53 and 0.37 g leaf^?1, of L. racemosa and A. schaueriana, respectively) and the highest plant density of this species (2,590 vs. 694 and 202 plant ha^?1, respectively) resulted in it having the greatest leaf productivity (10.6 Mg ha^?1 year^?1 compared to 2.4 Mg ha^?1 year^?1 for L. racemosa and 0.3 Mg ha^?1 year^?1 for A. schaueriana). The total leaf production is higher in this mangrove than most of those reported for other mangroves in the world.     

Nitrogen biogeochemistry of a mature Scots pine forest subjected to high nitrogen loads

Nitrogen (N) biogeochemistry of a mature Scots pine (Pinus sylvestris L.) stand subjected to an average total atmospheric N deposition of 48 kg ha^?1 year^?1 was studied during the period 1992–2007. The annual amount of dissolved inorganic nitrogen (DIN) in throughfall (TF) averaged 34 kg ha^?1 year^?1 over the 16-year monitoring period. The throughfall fluxes contained also considerable amounts of dissolved organic nitrogen (DON) (5–8.5 kg N ha^?1 year^?1), which should be incorporated in the estimate of N flux using throughfall collectors. Throughfall DIN fluxes declined at a rate of ?0.9 kg N ha^?1 year^?1, mainly due to the decreasing TF fluxes of ammonium (NH₄), which accounted for 70% to TF DIN. The decrease in TF DIN was accompanied by a decrease in DIN leaching in the seepage water (?1.6 kg N ha^?1 year^?1), which occurred exclusively as nitrate (NO₃ ^?). Nitrate losses in the leachate of the forest floor (LFH) equalled the TF NO₃ ^? delivered to the LFH-layer. On the contrary, about half of the TF NH₄ ⁺ was retained within the LFH-layer. Approximately 60% of the TF DIN fluxes were leached indicating that N inputs were far in excess of the N requirements of the forest. For DON, losses were only substantial from the LFH-layer, but no DON was leached in the seepage water. Despite the high N losses through nitrate leaching and NO _x emission, the forest was still accumulating N, especially in the aggrading LFH-layer. The forest stand, on the contrary, was found to be a poor N sink.     

ACE2 and FZD1 are prognosis markers in squamous cell/adenosquamous carcinoma and adenocarcinoma of gallbladder

The clinicopathological characteristics of squamous cell/adenosquamous carcinoma (SC/ASC) of the gallbladder have not been well documented, and no prognosis marker has been identified because of the rare occurrence of this gallbladder cancer subtype. In this study, we examined ACE2 and FZD1 expression in 46 SC/ASCs and 80 adenocarcinomas using immunohistochemistry and further analyzed their correlations with clinicopathological characteristics. We demonstrated that positive FZD1 and negative ACE2 expression were significantly associated with large tumor size, high TNM stage, lymph node metastasis and invasion of SC/ASC and AC. Univariate Kaplan–Meier analysis showed that positive FZD1 and negative ACE2 expression as well as differentiation, tumor size, TNM stage, lymph node metastasis, invasion, and surgical curability were closely associated with decreased overall survival in both SC/ASC (p < 0.001) and AC (p < 0.001) patients. The average survival time in SC/ASC and AC patients with FZD1^?ACE2⁺ expression was significantly longer than that in patients with FZD1⁺ACE2^? or FZD1⁺ACE2⁺ (p < 0.01). Multivariate Cox regression analysis showed that positive FZD1 and negative ACE2 expression are independent poor-prognostic factors for both SC/ASC and AC patients. In addition, FZD1 expression positively, but ACE2 expression negatively correlated with the expression of CA19-9 in SC/ASC and AC. Our study suggested that positive FZD1 and negative ACE2 expression are closely related to the expression of CA19-9; clinical, pathological, and biological behaviors; as well as poor-prognosis of gallbladder cancer.     

Effect of different doses of organic fertilizer (cow dung) on pond productivity and fish biomass in stillwater ponds

The effects of five (5 000, 10 000, 15 000, 20 000, 24 000 kg ha^?1 year^?1) different doses of organic fertilizer (cow dung) were studied on pond productivity in terms of plankton production and fish biomass in freshwater fish ponds. The grow out period was 60 days. Physico-chemical factors of pond waters were also monitored. With an increase in the fertilizer dose, biochemical oxygen demand (BOD) (1.7 ± 0.1 – 10.35 ± 0.05 mg L^?1), O-PO₄ (0.04 ± 0.0 – 0.77 ± 0.02 mg L^?1) and NH₄-N (0.03 ± 0.02 – 0.32 ± 0.02 mg L^?1) increased significantly (P < 0.05). Alkalinity (79.0 ± 1.6 – 164.0 ± 3.8 mg L^?1) also increased with the increase in fertilizer dose, declining after 60 and 75 days (48.8 ± 1.13 – 67.9 ± 2.1 mg L^?1). NO₃-N was maximum (1.66 ± 0.2 mg L^?1) in the ponds which received cow dung at 15 000 kg ha^?1 year^?1, and declined (0.94 ± 0.5 mg L^?1) at higher doses. Dissolved oxygen (DO) remained significantly high (4.7 mg L^?1) up to the third (15 000 kg ha^?1 year^?1) treatment. Highest plankton population (phytoplankton 17 350.0 ± 1 250.0 no L^?1), zooplankton (373.0 ± 22.0 no L^?1), species diversity (phytoplankton 3.0, zooplankton 2.3), fish biomass (4.45 kg) and specific growth rate (SGR) (2.36 % body weight (BW) d^?1) were also observed in ponds which were treated with fertilizer at 15 000 kg ha^?1 year^?1. However, at higher doses, a decline in these parameters (phytoplankton, 0.0 – 8 810.0 ± 690.0 no L^?1; zooplankton, 0.0 – 205.0 ± 25.0 no L^?1; fish biomass, 2.3 kg; SGR, 1.25 % body weight (BW) d^?1) was observed. Furthermore, with a decrease in the water temperature from 24 °C (on day 60) to 21 °C (on day 75), a decline in nutrient release, plankton population L^?1 and species diversity was observed. Sediment analysis indicated that with an increase in the fertilizer dosage, a significant and progressive increase in the accumulation of organic carbon (0.787 ± 0.006 – 0.935 ± 0.01), total nitrogen (0.877 ± 0.071 – 1.231 ± 0.03), NH₄-N (54.4 ± 0.57 – 68.95 ± 0.81), NO₃-N (78.5 ± 1.21 – 98.5 ± 0.35), total P (140.0 ± 0.50 – 151.0 ± 1.27) and soluble P (7.15 ± 0.18 – 10.1 ± 0.56) took place; similarly, electrical conductivity (EC) values of sediment also increased progressively (from 200.0 ± 7.1–300.0 ± 10.63 μ mhos cm^?1).