A modified drinking water quality index (DWQI) for assessing drinking source water quality in rural communities of Khuzestan Province,Iran

We reconsidered the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) to achieve an efficient drinking water quality index (DWQI) for assessment of drinking source water quality in rural communities of Khuzestan Province, Iran in 2009–2013. In contribution with a panel of water quality experts, the CCME WQI was mainly modified by four changes: (1 and 2) assigning weight factors for input parameters and index factors, (3) modifying excursion concept for carcinogens and bioaccumulative pollutants and (4) removing effect of unequal measurements of input parameters. The DWQI characterizes the drinking source water quality through comparing the measured values of input parameters with relevant benchmarks. The DWQI score (from 0 to 100) classifies the water quality in five categories as poor (0–54.9), marginal (55.0–69.9), fair (70.0–84.9), good (85.0–94.9) and excellent (95.0–100). Based on the DWQI, the temporal changes of the rural drinking source water quality were not significant; while the spatial variations of the water quality were considerable across the province, so the DWQI scores in the northern counties were higher than that in the southern ones. At the county level, the highest and lowest average scores of the DWQI (±standard deviation: SD) were observed in Izeh and Shadegan to be 90 ± 5 and 69 ± 10, respectively. Based on the DWQI, proportions of the drinking water sources with the excellent, good, fair, marginal and poor qualities were determined to be 6.7, 59.1, 26.2, 7.8 and 0.1%, respectively. Turbidity and Ryznar Index (RI) were introduced respectively as the health-based and esthetic parameters with the most violations (22.7 and 63.2%, respectively). The results of the case study and sensitivity analysis indicated that the DWQI is a simple, flexible, stable and reliable index and could be used as an effective tool to characterize drinking source water quality.     

Effects of supplemental urea sources and feeding frequency on ruminal fermentation,fiber digestion,and nitrogen balance in beef steers

The objective of two experiments was to evaluate non-protein N supplementation with protected urea sources in terms of rumen fermentation products, nutrient digestibility, and N balance in ruminally fistulated beef steers (initial bodyweight 239 ± 18 kg) fed switchgrass hay. Experiment 1 compared urea with Optigen II^®, and Experiment 2 compared urea with RumaPro^®. In both experiments, supplements (400 g/kg of daily dietary dry matter) were fed once daily or every 2 h in a balanced design. Supplements contained soybean hulls, corn grain, vitamins, and minerals as well as non-protein N sources. Non-protein N provided 0.18 g/g of dietary N. Switchgrass hay was fed once daily, at the same time as the supplement in the once-daily treatments. Dry matter intake (4.1 kg/d in Experiment 1, 4.5 kg/d in Experiment 2), dry matter digestibility (P<0.25, 0.58 ± 0.014 g/g in Experiment 1, 0.58 ± 0.010 g/g in Experiment 2), N balance (P<0.83, 11.3 ± 1.9 g/d in Experiment 1, 11.8 ± 3.6 g/d in Experiment 2), ruminal ammonia concentrations (P<0.29, 15.2 ± 1.4 mM in Experiment 1, 11.8 ± 0.6 mM in Experiment 2), and ruminal short-chain fatty acid concentrations (P<0.13, 77.7 ± 3.0 mM in Experiment 1, 75.4 ± 3.0 mM in Experiment 2) were not affected by feeding protected urea sources. Providing a steady supply of ruminally degradable N by feeding supplement every 2 h vs once daily decreased ruminal ammonia concentrations by approximately one-half by 4 h after feeding hay (P<0.01 in both experiments) and increased (P<0.02 in Experiment 1, P<0.08) in Experiment 2) apparent digestibility of dry matter (0.58–0.62 in Experiment 1, 0.56–0.61 in Experiment 2) and dietary fiber components.     

The influence of drinker location and colour on drinking behaviour and water intake of newborn pigs under hot environments

The effect of drinker location within the farrowing crate in relation to its microenvironment and the effect of dispenser colour on drinking behaviour and water intake of newborn pigs for the first two days of their lives were studied. In the first trial, 16 sows were randomly assigned to four treatment groups with the piglet's water dispenser placed in the front right (FR), front left (FL), back right (BR) or back left (BL) corner of the farrowing pen, respectively. In the second trial nine sows were randomly assigned to three treatment groups with the piglets’ water dispenser, placed in the front left corner of the farrowing pen, and coloured as red (CR), green (CG) or blue (CB), respectively. Trials commenced between 08:00 and 10:00 h on the first morning after the litters were born and the piglets’ age was considered to be zero (“age”) by that time.The average age of the piglets at their first visit to water dispensers was 15.9 ± 1.8 h. The newborn pigs visited the drinker more frequently (P < 0.001) during daytime than during night, with two peaks soon after sow feeding time. The duration of drinking time was long at the time of higher (noon) and shorter at the time of lowest (early morning) temperatures (P < 0.01) in the farrowing house, respectively. The greatest attention at the drinkers occurred soon after suckling (P < 0.001). The longest time spends at the drinker during the first visits and decreased as the pigs visited dispensers repeatedly. The profile of visit frequency and duration differed between piglet sexes (P < 0.001). The pigs that did not visit the drinker grew slower and were lighter at 48 h of age than the pigs visited the drinker. First visit and overall mean visit age were significantly shorter for BL than for FR and BR groups. Piglets visited the FL drinker for shorter time than the others. Water consumption per pig/24 h was lower for FL and higher for BL groups (P < 0.05). Water consumption was higher for CR and CB groups than for CG group. The overall mean visit age was shorter for CG than for CB group. Significant interactions were observed between sex and colour groups for the number of visits (P < 0.05). The results of the present study revealed that water dispenser use by newborn piglets is characterised by diurnal and between two successive milk consumptions distributions. Water consumption by piglets from birth to 48 h of their lives is strongly influenced by water dispenser location in the farrowing pen and the dispenser colour. It also appears that males and females behave differently to the three colour dispensers used in this study.     

An integrated constructed wetland to treat contaminants and nutrients from dairy farmyard dirty water

Water pollution by agriculture can include inappropriately managed dairy farmyard dirty water. In Ireland, dairy farmyard dirty water includes farmyard runoff, parlour washings, and silage/farmyard manure effluents. The objectives of this study were to determine (i) the quality and quantity of dirty water generated at a farm-scale and (ii) the seasonal effectiveness of a constructed wetland to treat farmyard dirty water. The wetland system was 4800 m² in area and treated dirty water from a 42-cow organic dairy unit with an open yard area of 2031 m². Monthly dirty water inflow rate to the wetland ranged between 3.6 and 18.5 m³ d⁻¹. Farmyard dirty water accounted for 27% of hydrological inputs to the wetland, whereas rainfall on wetland, along with wetland bank inflows accounted for 45 and 28%, respectively. Farmyard dirty water quality and quantity did not vary with season. Yearly mass loads discharged to the wetland were 47 ± 10 kg yr⁻¹ of soluble reactive phosphorus (SRP), 128 ± 35 kg yr⁻¹ of NH₄⁺, 5484 ± 1433 kg yr⁻¹ of organic material as measured by five-day biological oxygen demand (BOD₅), and 1570 ± 465 kg yr⁻¹ of total suspended solids (TSS). Phosphorus retention by the wetland varied with season (5–84%) with least amounts being retained during winter.     

Chlorination-mediated EPS excretion shapes early-stage biofilm formation in drinking water systems

Microbial surface adhesion to surfaces and subsequent biofilm establishment are ubiquitous in drinking water systems, which often contribute to deteriorated water quality. Disinfectants are common agents applied to drinking water controlling microbial propagation, yet the underlying mechanisms of how disinfectants function to regulate microbial activity and thereby biofilm development remains elusive. We experimentally studied the effects of chlorination on extracellular polymeric substance (EPS) production, and its impacts on early-stage biofilm formation in a model drinking water system. Results showed that low-level chlorine (≤ 1.0 mg/L) stimulated microbial EPS (especially of proteins) excretion that favored early-stage biofilm formation. Microbes experiencing higher chlorination (>1.0 mg/L) exhibited clearly suppressed growth associated with reduced EPS release, consequently yielding less biofilm formation. Removal of cell-attached proteins and polysaccharides diminished biofilm formation, which highlighted the critical role of EPS (especially protein components) in biofilm development. A negative correlation between chlorination-mediated microbial protein production and cell surface charge suggested that chlorine disinfection may modify cell surface properties through regulation of microbial EPS excretion and thereby mediate biofilm formation. With these quantitative estimations, this study provides novel insights into how chlorination-mediated EPS excretion shapes early-stage biofilm formation, which is essential for practical functioning of drinking water systems.     

The effect of water temperature and velocity on barnacle growth: Quantifying the impact of multiple environmental stressors

Organisms employ a wide array of physiological and behavioral responses in an effort to endure stressful environmental conditions. For many marine invertebrates, physiological and/or behavioral performance is dependent on physical conditions in the fluid environment. Although factors such as water temperature and velocity can elicit changes in respiration and feeding, the manner in which these processes integrate to shape growth remains unclear. In a growth experiment, juvenile barnacles (Balanus glandula) were raised in dockside, once-through flow chambers at water velocities of 2 versus 19 cm s⁻¹ and temperatures of 11.5 versus 14 °C. Over 37 days, growth rates (i.e., shell basal area) increased with faster water velocities and higher temperatures. Barnacles at high flows had shorter feeding appendages (i.e., cirri), suggesting that growth patterns are unlikely related to plastic responses in cirral length. A separate experiment in the field confirmed patterns of temperature- and flow-dependent growth over 41 days. Outplanted juvenile barnacles exposed to the faster water velocities (32±1 and 34±1 cm s⁻¹; mean±SE) and warm temperatures (16.81±0.05 °C) experienced higher growth compared to individuals at low velocities (1±1 cm s⁻¹) and temperatures (13.67±0.02 °C). Growth data were consistent with estimates from a simple energy budget model based on previously measured feeding and respiration response curves that predicted peak growth at moderate temperatures (15 °C) and velocities (20–30 cm s⁻¹). Low growth is expected at both low and high velocities due to lower encounter rates with suspended food particles and lower capture efficiencies respectively. At high temperatures, growth is likely limited by high metabolic costs, whereas slow growth at low temperatures may be a consequence of low oxygen availability and/or slow cirral beating and low feeding rates. Moreover, these results advocate for approaches that consider the combined effects of multiple stressors and suggest that both increases and decreases in temperature or flow impact barnacle growth, but through different physiological and behavioral mechanisms.     

Satellite monitoring of cyanobacterial harmful algal bloom frequency in recreational waters and drinking water sources

Cyanobacterial harmful algal blooms (cyanoHAB) cause extensive problems in lakes worldwide, including human and ecological health risks, anoxia and fish kills, and taste and odor problems. CyanoHABs are a particular concern in both recreational waters and drinking water sources because of their dense biomass and the risk of exposure to toxins. Successful cyanoHAB assessment using satellites may provide an indicator for human and ecological health protection. In this study, methods were developed to assess the utility of satellite technology for detecting cyanoHAB frequency of occurrence at locations of potential management interest. The European Space Agency's MEdium Resolution Imaging Spectrometer (MERIS) was evaluated to prepare for the equivalent series of Sentinel-3 Ocean and Land Colour Imagers (OLCI) launched in 2016 as part of the Copernicus program. Based on the 2012 National Lakes Assessment site evaluation guidelines and National Hydrography Dataset, the continental United States contains 275,897 lakes and reservoirs >1 ha in area. Results from this study show that 5.6% of waterbodies were resolvable by satellites with 300 m single-pixel resolution and 0.7% of waterbodies were resolvable when a three by three pixel (3 × 3-pixel) array was applied based on minimum Euclidian distance from shore. Satellite data were spatially joined to U.S. public water surface intake (PWSI) locations, where single-pixel resolution resolved 57% of the PWSI locations and a 3 × 3-pixel array resolved 33% of the PWSI locations. Recreational and drinking water sources in Florida and Ohio were ranked from 2008 through 2011 by cyanoHAB frequency above the World Health Organization’s (WHO) high threshold for risk of 100,000 cells mL⁻¹. The ranking identified waterbodies with values above the WHO high threshold, where Lake Apopka, FL (99.1%) and Grand Lake St. Marys, OH (83%) had the highest observed bloom frequencies per region. The method presented here may indicate locations with high exposure to cyanoHABs and therefore can be used to assist in prioritizing management resources and actions for recreational and drinking water sources.     

Diurnal exchanges of CO2 and CH4 across the water–atmosphere interface in a water chestnut meadow (Trapa natans L.)

CH₄ and CO₂ fluxes across the water–atmosphere interface were measured over a 24 h day–night cycle in a shallow oxbow lake colonized by the water chestnut (Trapa natans L.) (Lanca di Po, Northern Italy). Only exchanges mediated by macrophytes were measured, whilst gas ebullition was not considered in this study. Measurements were performed from 29 to 30 July 2005 with short incubations, when T. natans stands covered the whole basin surface with a mean dry biomass of 504 ± 91 g m⁻². Overall, the oxbow lake resulted net heterotrophic with plant and microbial respiration largely exceeding carbon fixation by photosynthesis. The water chestnut stand was a net sink of CO₂ during the day-light period (−60.5 ± 8.5 mmol m⁻² d⁻¹) but it was a net source at night (207.6 ± 6.1 mmol m⁻² d⁻¹), when the greatest CO₂ efflux rate was measured across the water surface (28.2 ± 2.4 mmol m⁻² h⁻¹). The highest CH₄ effluxes (6.6 ± 1.8 mmol m⁻² h⁻¹) were determined in the T. natans stand during day-time, whilst CH₄ emissions across the plant-free water surface were greatest at night (6.8 ± 2.1 mmol m⁻² h⁻¹). Therefore, we assumed that the water chestnut enhanced methane delivery to the atmosphere. On a daily basis, the oxbow lake was a net source to the atmosphere of both CO₂ (147.1 ± 10.8 mmol m⁻² d⁻¹) and CH₄ (116.3 ± 8.0 mmol m⁻² d⁻¹).     

Effects of intermittent watering on water balance and feed intake in male Ethiopian Somali goats

The objective of this study was to investigate the regulation of water balance and dry matter (DM) intake of male Ethiopian Somali goats. Twenty-eight goats were grouped into four treatments; goats watered every day (W1), every 2nd day (W2), every 3rd day (W3) and every 4th day (W4) for a total period of 72 days. Plasma sodium and potassium were analyzed by flame photometry, plasma osmolality by freezing point depression, plasma protein concentration by TS refractometry, and the plasma vasopressin concentration by radioimmunoassay. Goats were fed grass hay ad libitum and were given 200 g of concentrates daily. The calculated daily water intake (ml/kg BW^0.75) of W1, W2, W3 and W4 was 128 ± 4, 86 ± 4, 88 ± 4 and 78 ± 4, respectively, (P < 0.001, W1 versus the other groups). Calculated total concentrates intake did not change, whereas Group W2 and W4 consumed less hay on days of water deprivation (W1 versus W2, P < 0.01; W1 versus W4, P < 0.001). Plasma sodium concentration of W1 was 143 ± 1 mmol/l. Intermittent watering increased plasma sodium concentration from 140 or 141 ± 1 mmol/l to 145 or 146 ± 1 mmol/l every 2nd day in group W2. In W3, it increased from 139 ± 1 to 146 ± 1 mmol/l and in W4 from 137 ± 1 to 149 ± 1 mmol/l (P < 0.001 for all) on days after watering compared to last day of water deprivation, respectively. Corresponding changes were observed in plasma osmolality. Total plasma protein concentration increased only in W3 from 65 ± 1 to 67 ± 1 mmol/l on day 3 (P < 0.01) and in W4 from 65 ± 1 to 67 and 68 ± 1 mmol/l on days 3 and 4, respectively (P < 0.05). The plasma vasopressin concentration of W1 was close to 0.80 ± 0.28 pmol/l on all days, but it increased on dehydration days in W2 (P < 0.05). In W3, the vasopressin concentration increased from 0.95 or 1.19 pmol/l the day after watering to 3.11 ± 0.28 pmol/l on day 3 (P < 0.01). In W4, it was 0.82 ± 0.31 pmol/l the day after watering and reached 6.06 ± 0.31 pmol/l on day 4 (P < 0.001). We conclude that male Ethiopian Somali goats can be watered once every 3rd days, and that longer interval is not recommended because it demands marked mobilization of water saving mechanisms and causes decreased DM intake.     

Estimation of iron requirements for women by numerical analysis of population-based data from the National Health and Nutrition Surveys of Japan 2003–2007

Iron requirements were estimated from the results of the National Health and Nutrition Surveys of Japan 2003–2007 using the numerical analysis of requirements based on an integral equation. The numerical analysis used population-based data on iron nutriture, the prevalence of inadequate iron status, and the distribution of iron intakes. The cutoff value for inadequate iron status was defined as a serum ferritin concentration <30 ng/mL. Iron intakes and menstrual blood losses followed a log-normal distribution and published values were corrected accordingly to calculate usual values. For women aged 18–29 years old, the median of the estimated median iron requirement (corresponding to the estimated average requirement by using the terminology of the dietary reference intakes) was 7.59 mg (range, 6.86–8.11). The median of the estimated usual iron intake covering the needs of women with 80 mL per cycle of menstrual blood loss was 11.27 mg (range, 10.16–12.00), and the median of the usual iron intake covering the needs of 97.7% of women was 13.93 mg (range, 12.55–14.81). For women aged 30–49 years old, the corresponding figures were 8.13 mg (range, 7.96–8.69), 11.95 mg (range, 11.72–12.77), and 14.71 mg (range, 14.44–15.72).     

Ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the water from a large Chinese lake based on multiple indicators

In the surface water of Lake Chaohu, China, the concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured by gas chromatograph–mass spectrometer (GC–MS). Based on the species sensitivity distribution (SSD) model and the probabilistic risk assessment (PRA) model, the indicators were calculated to assess the potential ecological risk of the individual and of multiple congeners of PAHs and their probabilities. The results revealed that the average residual level of the total PAHs (PAH₁₆) in the water ranged from 95.2 to 370.1 ng/L, with a mean value 181.5 ± 70.8 ng/L. The PAH content in the water was dominated by the low-molecular-weight congeners. The multi-substance potentially affected fractions (msPAFs) of the studied PAHs obtained by the SSD model varied from 0.29% (site B3) to 1.58% (site B6), with an average of 0.51 ± 0.34%. The average of the msPAFs (0.93%) for the inflow rivers was greater than that for the western (0.42%) and eastern (0.34%) parts of the lake. The greatest ecological risk probability calculated by the PRA model was found for Pyr (1.55%), followed by Ant (7.07 × 10⁻²%), Fla (2.21 × 10⁻²%), Phe (9.25 × 10⁻⁶%), Nap (1.01 × 10⁻⁵%), Flo (1.16 × 10⁻¹⁴%) and Ace (2.86 × 10⁻¹⁶%). The same order of ecological risks calculated by the two models was found for the studied PAH compounds. The toxicity data might be the primary source of the ecological risk uncertainties, as indicated by the greater values of coefficients of variation (CV) for the toxicity. This study concluded that the combinations of multiple indicators based on the SSD and PRA models for the ecological risk assessment are necessary to provide more general information on the spatial variations and the probabilities of potential ecological risks of the individual and multiple congeners of PAHs.     

Remote sensing of chlorophyll-a concentration for drinking water source using genetic algorithms (GA)-partial least square (PLS) modeling

Accurate estimation of phytoplankton chlorophyll-a (Chl-a) concentration in turbid waters through remote sensing is a challenge due to the optical complexity of water constituents. Reflectance spectra and concurrent water quality parameters of 225 samples across the Shitoukoumen Reservoir, the drinking water resource for Changchun City, were used to retrieve Chl-a concentration with high total suspended matter (TSM) during 2006–2008. A combination of genetic algorithms and partial least square (GA-PLS) model was established for Chl-a retrieval through GA to select sensitive spectral variables and PLS for regression. To compare GA-PLS performances, the widely accepted three-band algorithm was implemented for Chl-a concentration estimation. Both GA-PLS and the three-band algorithm have stable performance for the aggregated dataset (R² = 0.85 and 0.81; RPD = 3.95 and 3.61; relative RMSE = 31.7% and 34.2%), with the GA-PLS model performing marginally better. The temporal transferability of the models was validated with the dataset collected in 2006 and 2007 respectively as independent dataset, showing that GA-PLS outperformed the three-band algorithm. Our result also indicated that relative error [(Chl-a_predicted − Chl-a_measured) / Chl-a_measured] showed good linear relation to TSM: Chl-a ratio (R² = 0.84), which implied that TSM concentration exerted significant impact on the accuracy of Chl-a estimation in this case study. As the results were derived from a large number of samples representing a wide range of spatiotemporal variations of pigment under TSM (3.7–472.8 mg/L) concentration influence, the GA-PLS model has great potential for Chl-a estimation for inland waters with similar backgrounds. Nevertheless, the three-band algorithm also has its own merit considering its simplicity for implementation.     

Effects of diets of differing fiber contents on digestibility,passage rate of digesta and heat production in lesser mouse deer (Tragulus javanicus)

The effects of different levels of dietary fiber on feed intake, digestibility, mean retention times of solute and particle and heat production were studied in twelve male lesser mouse deer (Tragulus javanicus). The animals were randomly assigned into four groups of three mouse deer each and fed on individual basis. Four diets, namely A, B, C and D were prepared in pellet forms. Each diet contained ～14% crude protein and ～18 kJ/g gross energy. The crude fiber contents of diet A, B, C and D were 4.2, 11.3, 16.8 and 22.5%, respectively. The results showed that the crude fiber intake of mouse deer was 1.4 ± 0.04, 3.8 ± 0.4, 5.8 ± 0.7 and 6.0 ± 0.6 g/kg W^0.75/d fed diet A, B, C and D, respectively. Mouse deer fed diet D had significantly lower DM intake than those fed lower levels of fiber. The digestibility values of DM decreased gradually with increasing levels of fiber in the diet. The mean retention times (MRTs) of particles (～1.5 mm) in the reticulorumen were in the range of (19.0–22.9 h), with the shortest time for mouse deer fed diet D. However mouse deer fed diet C and D showed significant shorter solute MRT in the reticulorumen (17.1–18.5 h) when compared to mouse deer fed lower fiber diets (21.4–21.9 h). The selectivity factor in the reticulorumen was in the range of 1.04–1.18, indicating the mouse deer to be a ‘moose-type’ ruminant. Fiber levels had no significant effect on water intake of mouse deer. Heat production tended to decrease with increasing levels of fiber (448.3–435.7 kJ/kg W^0.75/d) but differences among the mouse deer fed the four diets were not significant.     

Phytochemical characterization of potential nutraceutical ingredients from Evening Primrose oil (Oenothera biennis L.)

Evening Primrose oil (EPO) is a natural product extracted by cold-pressed from Oenothera biennis L. seeds. EPO is widely used as a dietary supplement from which beneficial effects have been reported in rheumatic and arthritic conditions, atopic dermatitis, psoriasis, premenstrual and menopausal syndrome, and diabetic neuropathy. The beneficial effects of EPO are thought to be due to its γ-linolenic acid content; in contrast, little effort has been expended to characterize the non-triglyceridic constituents of EPO. In order to evaluate its potential as source of functional food ingredients our aim in this work has been identified and quantified the different components of EPO by different techniques (GC–MS and HPLC). The lipid profile showed that oleic (7%), linoleic (74%) and γ-linolenic (9%) were the most abundance fatty acids. Unsaponifiable matter and subfractions were obtained by CEE/2568/91. Separation of the compounds under study was achieved giving a reasonable analysis time and good resolution. A yield (1.82–1.95%) of unsaponifiable matter was obtained and levels of saturated hydrocarbons (0.291.97 ± 14.85 mg) were noticed. β-Sitosterol (7952.00 ± 342.25 mg/kg oil) and campesterol (883.32 ± 0.45 mg/kg oil) were predominant in phytosterol fraction (9573 mg/kg oil), while tetracosanol (236.93 ± 2.32 mg/kg oil) and hexacosanol (289.92 ± 3.41 mg/kg oil) in linear aliphatic alcohol fraction (798.04 ± 5.66 mg/kg oil). In the phenolic fraction (55.49 ± 2.76 mg/kg oil), ferulic acid (25.23 ± 2.64 mg/kg oil) was the major component. From the results obtained, it can be suggested that the Evening Primrose oil can be considered an interesting alimentary source of substances of nutraceutical value.     

EMG normalization to study muscle activation in cycling

The value of electromyography (EMG) is sensitive to many physiological and non-physiological factors. The purpose of the present study was to determine if the torque–velocity test (T–V) can be used to normalize EMG signals into a framework of biological significance. Peak EMG amplitude of gluteus maximus (GMAX), vastus lateralis (VL), rectus femoris (RF), biceps femoris long head (BF), gastrocnemius medialis (GAS) and soleus (SOL) was calculated for nine subjects during isometric maximal voluntary contractions (IMVC) and torque–velocity bicycling tests (T–V). Then, the reference EMG signals obtained from IMVC and T–V bicycling tests were used to normalize the amplitude of the EMG signals collected for 15 different submaximal pedaling conditions. The results of this study showed that the repeatability of the measurements between IMVC (from 10% to 23%) and T–V (from 8% to 20%) was comparable. The amplitude of the peak EMG of VL was 99 ± 43% higher (p < 0.001) when measured during T–V. Moreover, the inter-individual variability of the EMG patterns calculated for submaximal cycling exercises differed significantly when using T–V bicycling normalization method (GMAX: 0.33 ± 0.16 vs. 1.09 ± 0.04, VL: 0.07 ± 0.02 vs. 0.64 ± 0.14, SOL: 0.07 ± 0.03 vs. 1.00 ± 0.07, RF: 1.21 ± 0.20 vs. 0.92 ± 0.13, BF: 1.47 ± 0.47 vs. 0.84 ± 0.11). It was concluded that T–V bicycling test offers the advantage to be less time and energy-consuming and to be as repeatable as IMVC tests to measure peak EMG amplitude. Furthermore, this normalization method avoids the impact of non-physiological factors on the amplitude of the EMG signals so that it allows quantifying better the activation level of lower limb muscles and the variability of the EMG patterns during submaximal bicycling exercises.     

Impact of nutrients and herbivory by Eccritotarsus catarinensis on the biological control of water hyacinth,Eichhornia crassipes

Many water hyacinth infestations in South Africa are the symptom of eutrophication, and as a result, biological control of this weed is variable. This study examined the effects of herbivory by the mirid, Eccritotarsus catarinensis, on water hyacinth grown at high, medium and low nitrogen (N) and phosphorus (P) nutrient concentrations. Water nutrient concentration appears to be the overriding factor affecting plant growth parameters of water hyacinth plants—at high nutrient concentrations, leaf and daughter plant production were more than double than at low nutrient concentrations, while stem length was twice as great at high nutrient concentrations compared to low concentrations. Chlorophyll content was also twice as high at high nutrient concentrations than low concentrations. Conversely, flower production at high nutrient concentrations was less than half that at low concentrations. Herbivory by E. catarinensis did not have as great an effect on water hyacinth vigour as nutrient concentration did, although it significantly reduced the production of daughter plants by 23 ± 9%, the length of the second petiole by 13 ± 5%, and chlorophyll content of water hyacinth leaves by 15 ± 6%. In terms of insect numbers, mirids performed better on plants grown under medium nutrient conditions (99 ± 28 S.E.), compared to high nutrient concentrations (52 ± 27 S.E.), and low nutrient concentrations (25 ± 30 S.E.). Thus, these results suggest that the fastest and most significant reduction in water hyacinth proliferation would be reached by lowering the water nutrient concentrations, and herbivory by E. catarinensis alone is not sufficient to reduce all aspects of water hyacinth vigour, especially at very high nutrient concentrations.     

Structure and water permeability of fully hydrated diphytanoylPC

Diphytanoylphosphatidylcholine (DPhyPC) is a branched chain lipid often used for model membrane studies, including peptide/lipid interactions, ion channels and lipid rafts. This work reports results of volume measurements, water permeability measurements P_f, X-ray scattering from oriented samples, and X-ray and neutron scattering from unilamellar vesicles at T = 30 °C. We measured the volume/lipid V_L = 1426 ± 1 Å³. The area/lipid was found to be 80.5 ± 1.5 Å² when both X-ray and neutron data were combined with the SDP model analysis (Ku?erka, N., Nagle, J.F., Sachs, J.N., Feller, S.E., Pencer, J., Jackson, A., Katsaras, J., 2008. Lipid bilayer structure determined by the simultaneous analysis of neutron and X-ray scattering data. Biophys. J. 95, 2356–2367); this is substantially larger than the area of DOPC which has the largest area of the common linear chain lipids. P_f was measured to be (7.0 ± 1.0) × 10^?3 cm/s; this is considerably smaller than predicted by the recently proposed 3-slab model (Nagle, J.F., Mathai, J.C., Zeidel, M.L., Tristram-Nagle, S., 2008. Theory of passive permeability through lipid bilayers. J. Gen. Physiol. 131, 77–85). This disagreement can be understood if there is a diminished diffusion coefficient in the hydrocarbon core of DPhyPC and that is supported by previous molecular dynamics simulations (Shinoda, W., Mikami, M., Baba, T., Hato, M., 2004. Molecular dynamics study on the effects of chain branching on the physical properties of lipid bilayers. 2. Permeability. J. Phys. Chem. B 108, 9346–9356). While the DPhyPC head–head thickness (D_HH = 36.4 Å), and Hamaker parameter (H = 4.5 × 10^?21 J) were similar to the linear chain lipid DOPC, the bending modulus (K_C = 5.2 ± 0.5 × 10^?21 J) was 30% smaller. Our results suggest that, from the biophysical perspective, DPhyPC belongs to a different family of lipids than phosphatidylcholines that have linear chain hydrocarbon chains.     

Uptake of advanced glycation end products by proximal tubule epithelial cells via macropinocytosis

Chronic hyperglycaemia during diabetes leads to non-enzymatic glycation of proteins to form advanced glycation end products (AGEs) that contribute to nephropathy. We describe AGE uptake in LLC-PK1 and HK2 proximal tubule cell lines by macropinocytosis, a non-specific, endocytic mechanism. AGE–BSA induced dorsal circular actin ruffles and amiloride-sensitive dextran–TRITC uptake, significantly increased AGE–BSA–FITC uptake (167 ± 20% vs BSA control, p < 0.01) and was ezrin-dependent. AGE–BSA–FITC uptake was significantly inhibited by amiloride and inhibitors of Arf6, Rac1, racGEF Tiam1, PAK1 and actin polymerisation. AGE–BSA–FITC, Arf6 and PIP2 co-localised within dorsal circular actin ruffles. AGE–BSA increased PAK1 kinase activity (212 ± 41% vs control, p < 0.05) and protein levels of Tiam1, a Rac1 activator. AGE–BSA significantly increased TGF-β₁ protein levels (160 ± 6%, p < 0.001 vs BSA), which were significantly inhibited by inhibitors of Arf6 (82 ± 19%, p < 0.001 vs AGE) and actin polymerisation (107 ± 11%, p < 0.001 vs AGE), suggesting AGEs partially exert their profibrotic effects via macropinocytosis. PAK1 and PIP5Kγ siRNA significantly decreased AGE–BSA–FITC uptake (81 ± 6% and 64 ± 7%, respectively, p < 0.05 vs control for both), and AGE-stimulated TGF-β₁ protein release (99 ± 15% and 49 ± 8% of control, p < 0.05 and p < 0.001, respectively). Inhibition of AGE uptake by macropinocytosis inhibitors and a neutralising TGF-β antibody, reversed the AGE-induced decrease in surface Na⁺K⁺ATPase, suggesting AGE uptake by macropinocytosis may contribute to diabetic kidney fibrosis and/or EMT by modulating this pump. Understanding methods of cellular uptake and signalling by AGEs may lead to novel therapies for diabetic nephropathy.     

Subcellular fractionation of Cu exposed oysters,Crassostrea virginica,and Cu accumulation from a biologically incorporated Cu rich oyster diet in Fundulus heteroclitus in fresh and sea water

In order to examine the effect of salinity on Cu accumulation from a naturally incorporated diet, oysters (Crassostrea virginica) were exposed in sea water for 96 days to four waterborne [Cu]: 2.9 ± 0.7 (control), 4.3 ± 0.6, 5.4 ± 0.5, and 10.7 ± 1.0 µg L^? 1. After 96 days, the control whole body [Cu] increased from 2.1 ± 0.5 to 9.1 ± 1.1 µg g^? 1 w.w. and the highest [Cu] was 163.4 ± 27.1 µg g^? 1 w.w. in the oysters. Despite large differences in tissue [Cu], there was no effect on the fraction of trophically available metal in the oyster suggesting that trophic transfer will correlate well with tissue [Cu]. The control and highest [Cu] oysters became diet for killifish (Fundulus heteroclitus) in fresh and seawater for 40 days. The two diets contained 84.7 ± 5.1 and 850.5 ± 8.8 µg Cu g^? 1 d.w. Fish were fed a combined diet of oyster and a pellet supplement (20.5 ± 1.0 µg Cu g^? 1 d.w.) both at 5% body mass day^? 1. In killifish, Cu increased ~ 7% in gills and 100% in intestines after 6 weeks of exposure to the high Cu diet. No other tissues accumulated Cu above control levels. An 11-fold difference free Cu²⁺ concentrations was predicted in intestinal fluid between fresh and sea water, but there was no corresponding effect of salinity on intestinal Cu accumulation suggesting that Cu is not accumulated as the free ion.