The role of osmotic factors in the effect of mineral water Naftusia on smooth muscles of the portal vein

The effect of the Krebs solution tonicity on the electrical and mechanical activity of smooth muscles has been studied while adding 1-5% volume of mineral water Naftusya, its artificial salt analog, and distilled water into the above solution. It is shown that effects observed are induced by the medium tonicity changes rather than by biologically active components of the mineral water. The smooth muscle cells of the rat portal vein are sensitive osmometers which affect hypotonic Krebs solution by 1%.     

Digestive and transport enzymes of the small intestine under the action of low-mineralized water "Naftusya" and its components

Mineral water Naftusya and its components: macrosalt analog and bitumen fraction have been studied in vitro for their effect on enzymes of the mucous small intestine membrane: M2+ and Na+, K+-ATPase, alpha-amylase, proteinase and leucine aminopeptidase. It is shown that certain components of mineral water are able to change activity of some enzymes. Transport Na+, K+-ATPase proved to be the most sensitive to the action of studied factors. Mineral water and bitumen fraction induced an increase of the enzyme activity by 23, 20 and 45%, respectively. Mineral water and its salt analog induced inhibition of leucine aminopeptidase: its activity decreased by 16 and 15%, respectively. Digestive enzymes: alpha-amylase and proteinase are resistant to the action of mineral water and its components.     

The relationship of the processes of recovery from thermal and radiation damage in yeast cells

Synergistic enhancement coefficient (SEC) achieves the maximum value within 2-3 hours of holding overheated (50 degrees C) and gamma-irradiated diploid cells of Sacch. cerevisiae in water at 28 degrees C; further holding leads to SEC dropping almost to the initial value. The maximum in the curve involved disappears if gamma-irradiated (overheated) cells were held in water at 28 degrees C for 2-3 hours before hyperthermic treatment (gamma-irradiation). There is no maximum in the curve discussed for haploid yeast cells, which are incapable of "rapid" post-irradiation recovering. The experimental data are interpreted from the point of view of reversible inhibition of yeast post-irradiation recovery by hyperthermia.     

Studies on conidial germination and initial growth of the grapevine powdery mildew Uncinula necator on artificial substrates

Summary The requirements for conidial germination and formation of infection structures of the grapevine parasites Uncinula necator were studied on different substrates and supports. Direct contact with water or agar surfaces frequently caused bursting of conidia or inhibited formation of infection structures. Normal germination and initial growth depended on the presence of a dry surface covering a liquid substrate which could be reached by the penetration pegs. The water necessary for germination must be provided by a high air humidity whose optimal value (99.8%) was determined using closed slide microchambers in which air humidity was controlled by salt solutions. Even 99.6% humidity led to significant growth reduction, while at higher values deleterious condensation droplets formed around the spores. If liquid substrates are covered with thin (0.5 m), waterproof polyacrylic membranes, germination appears normal. Formation of appressoria, successful penetration of the membrane by infection pegs and the development of functional haustoria indicate a lack of host specifity during the initial growth stage. although on water and on glucose media growth stopped after 1–2 weeks, this method seems to indicate a way to axenically culture this obligate parasite. The lack of host specificity at the level of host surface or tissue anatomy was corroborated by a successful culture of powdery mildew on grapevine callus.Dedicated to Professor Dr. Dr. hc. K. Esser on the occasion of his 65th anniversary     

Bioremediation of phenolic compounds having endocrine-disrupting activity using ozone oxidation and activated sludge treatment

The bioremediation of water system contaminated with phenolic compounds having endocrine-disrupting activity,i.e. 2,4-dichlorophenol, 2,4-dichlorophenoxy acetic acid (2,4-D), and 2,4,5-trichlorophenoxy acetic acid (2,4,5-T), was investigated by using ozone oxidation and activated sludge treatment. Ozone oxidation (ozonation time: 30 min) followed by activated sludge treatment (incubation time: 5 days) was an efficient treatment method for the conversion of phenolic compounds in water into carbon dioxide and decreased the value of total organic carbon (TOC) up to about 10% of initial value. Furthermore, 2,4-D was dissolved in water containing salt,i.e. artificial seawater (ASW), and this water was used as model coastal water contaminated with phenolic compounds. The activated sludge treatment (incubation time: 5 days) could consume significantly organic acids produced from 2,4-D in the model costal water by the ozone oxidation (ozonation time: 30 min) and decrease the value of TOC up to about 35% of initial value.     

Computer simulation of the initial proton transfer step in human carbonic anhydrase I.

The initial water proteolysis step in the proton transfer "half-reaction" of human carbonic anhydrase I is simulated using the empirical valence bond method in combination with free energy perturbation molecular dynamics calculations. A free energy profile for the enzyme catalysed reaction and the corresponding pKa associated with ionization of the zinc-bound water is calculated. The obtained pKa value of 7 to 8 appears to be in good agreement with experimental observations and the calculated rate constant for this step is also compatible with kinetic data. The simulations clearly emphasize the important electrostatic effect associated with the catalytic zinc ion.     

Evaluation of canopy transpiration rate by applying a plant hormone “abscisic acid”

A method for evaluation of temporal changes in canopy transpiration rate and stomatal conductance in crop fields by using a plant hormone abscisic acid (ABA) has recently been developed. The method was applied to a corn canopy at different growth stages in the upper Yellow River basin, China. Diurnal changes in the canopy transpiration rate and stomatal conductance were evaluated at the initial stage with a leaf area index (LAI) of 0.37 on June 7 and the crop development stage with an LAI of 4.39 on July 15, 2005. The proportions of the accumulated transpiration rate during daytime to the accumulated evapotranspiration were 24% and 74% at the initial and crop development stages, respectively. Stomatal conductance varied in parallel with transpiration rate in the initial stage of the crop. However, in the crop development stage with low soil water content, stomatal conductance reached the maximum value at 10:00 a.m. and thereafter decreased rapidly at around noon with high evaporative demand to corn canopy. This shows the midday stomatal closure was caused by excessive water stress to corn canopy in the crop development stage. Thus, the proposed method with ABA application is useful for evaluation of temporal changes in transpiration rate and stomatal conductance, and hence, can detect the plant water stress.     

Effect of temperature on early development of the Pacific mussel <Emphasis Type="Italic">Mytilus trossulus</Emphasis> (Bivalvia: Mytilidae) in sea water polluted by copper ions

The effects of water temperatures of 7, 15 and 20°C and pollution of sea water by copper ions in concentrations of 0.005 and 0.01 mg/l on the early development of the Pacific mussel Mytilus trossulus were studied. It was shown that copper additives were most toxic at the initial stages of development, from fertilization up to the veliger stage. It was determined that larvae of the Pacific mussel were able to adapt to copper at a concentration of 0.005 mg/l. The copper toxicity increased to a greater extent with an increase in water temperature from its average value of 15°C, than with a temperature decrease.     

An optimum method for the introduction or removal of permeable cryoprotectants: Isolated cells

On the basis of a nonequilibrium model for the transport of water and permeable solute across cell membranes, an optimum method has been devised for the introduction and the removal of a permeable cryoprotectant from single, isolated cells so that potentially lethal drastic alterations in cellular volume are minimized. The method involves the simultaneous variation of both the permeable (an initial step change, followed by a linear variation with time which overshoots the terminal value, and a final step change to the terminal value) and impermeable (an initial step change in the opposite direction of the permeable solute concentration change, followed by a period where the concentration remains constant, and a final step change back to the initial value) extracellular solute concentrations in a prescribed manner such that both the cellular water content and the intracellular electrolyte concentration remain constant as the intracellular permeable solute (CPA) concentration is either raised or lowered. The results of our theoretical analysis indicate that the osmotic stresses and strains usually imposed upon cells during the introduction and the removal of permeable cryoprotectants can be minimized and that the resulting protocols are clinically the most efficient.     

Carbon dioxide gas exchange and the energy status of leaves of Primula palinuri under water stress

The photosynthetic rate of water stressed leaves of Primula palinuri was reduced drastically by stomatal closure, not by limitations imposed on the capacity of the photosynthetic apparatus, when water loss exceeded 20% of the water content of turgid leaves. The sudden decrease in phtosynthesis was not observed when the lower epidermis of the leaves had been removed. In these ‘stripped’ leaves, inhibition of photosynthesis increased only gradually during the wilting caused by increasing water stress and was complete when the relative water content was as low as 20% compared with the initial value. This corresponded to a water potential of about-40 bar. The light intensity at which half-maximum rates of photosynthesis were observed decreased as stress increased. In intact leaves photosynthesizing in the presence of CO₂, light scattering, which is a measure of thylakoid energization, increased steeply during stomatal closure. The observed increase corresponded to the light scattering level measured in the absence of CO₂. When the lower epidermis was removed, no sudden increase in thylakoid energization could be observed during dehydration. Thylakoid energization remained high even at low water potentials. It decreased drastically only below a relative water content of 20%. Irrespective, of the extent of water stress, CO₂ fixation of stripped leaves increased when the oxygen content of air was reduced from 21% to 2%. Usually the transition from 21 to 2% O₂ was accompanied by increased thylakoid energization. The increase in energization was more pronounced below than above a relative water content of 50%. The data show that energy-dissipating photorespiratory CO₂ turnover in the in tercellular space of water-stressed leaves whose stomata are closed decreases only slowly as water stress increases. Respiratory CO₂ production by leaves in the dark was even more resistant to water stress than photosynthesis. It was still significant at water potentials as low as-80 bar.     

Organic solvents for bioorganic synthesis

Summary The influence of solvents on enzymatic activity and stability was investigated. As a model reaction the -chymotrypsin-catalyzed esterification of N-acetyl-l-phenylalanine with ethanol was used. The enzyme was adsorbed on porous glass beads and used in various solvents. Small amounts of water were added to increase the enzymatic activity. These enzyme preparations obeyed. Michaelis-Menten kinetics. K _m,app decreased slightly with the log P value of the solvent while V _app increased markedly with the log P value. Log P values were also useful for generalizing the influence of solvents on enzyme stability. The enzyme preparations showed a markedly higher thermostability in dry solvents having log P values >0.7 than in less hydrophobic solvents.Also the operational stability was better in the more hydrophobic solvents. The amount of water added to the enzyme preparations greatly influenced the initial reaction rates. For some solvents optimal water contents were determined. The thermostability decreased with increasing water content.The observations are summarized in the conclusion that more hydrophobic solvents are preferable to less hydrophobic ones. The log P value gives a good guidance when selecting an organic solvent for enzymatic conversions.     

The role of soil hydraulic conductivity on the spatial and temporal variation of root water uptake in drip-irrigated corn

A multiplexed TDR system and a heat-pulse system for stem sap flow measurements were used to determine the spatial and temporal pattern of root water uptake in field-grown corn. The TDR probes, 0.15 and 0.30 m in length, were buried vertically in the soil profile to a depth of 0.95 m below the soil surface and heat-pulse sensors were installed on the plant base. Nocturnal readings from TDR probes were used successfully to differentiate the two components of moisture change: root uptake and net drainage. The instantaneous rate of water extraction by the plant measured by the heat-pulse system agreed well with the integrated rate of root water uptake measured frequently (at half-hour or hourly intervals) by the TDR probes. This agreement enabled further exploration into the cause of the evolution of the spatial and temporal patterns of root water uptake during a drying cycle. The results indicated that right after irrigation in the well-watered soil profile, it is the spatial distribution of the roots that mainly determines the typical pattern of root extraction, in addition to the fact that the roots near the plant base are more effective than those farther away. The higher density and effectiveness of the roots near the plant base dry the soil rapidly so that soil hydraulic conductivity soon becomes a limiting factor for water uptake. Further analysis revealed that a decrease in root uptake occurs near the plant base under a given atmospheric demand when the relative bulk soil hydraulic conductivity decreases to 0.002K _r. This suggests that low conductivity (high resistance) in the soil near the plant base is the initial cause for downward and lateral shifting of the root uptake pattern. Note that this critical value of hydraulic conductivity is not universal since it depends on the soil type and atmospheric water demand during the period under observation. Therefore, prior to the application of moisture content or suction head as measures of water availability or to control irrigation scheduling, it is suggested that these parameters be calibrated by the soil K() or K() curves, respectively, for the expected atmospheric water demand for the specific crop and growing period.     

Water scarcity footprint of primary aluminium

Purpose

The cradle-to-gate water scarcity footprint (WSFP) of primary aluminium has been determined for global aluminium including China (GLO) and global aluminium excluding China (RoW). It consists of the following:

• the direct WSFP, based on the freshwater consumption data collected by the IAI from global bauxite mines, alumina refiners and aluminium smelters and the local water scarcity index (WSI) of each plant, and
• the indirect WSFP which has been calculated using data collected by thinkstep on the freshwater consumption of the different ancillary materials, of the fuel and of the electricity needed for the production of alumina and aluminium and the relevant water scarcity indexes.

Methods

The calculation of the direct WSFP follows the requirement of ISO 14046 to aggregate data of sites at locations with different water scarcity after multiplication with the local water scarcity index.For the indirect WSFP, regional averages of the water consumption and water scarcity index were used for an initial screening study to determine fields for further investigation. Results of this study demonstrate that data on evaporation of water from reservoirs of hydropower plants has an extremely high contribution to the indirect WSFP of primary aluminium (79 % of the GLO value and 92 % of the RoW value).Therefore, a plant-by-plant approach was applied for hydropower which considers the net freshwater consumption of the hydropower reservoirs and uses the local water scarcity index of each power station, individually, for the calculation of the generic WSFP of the country or region. A special treatment has been given to some multipurpose reservoirs which typically have a beneficial effect on water scarcity, i.e. they have a negative WSFP if seasonal water scarcity indices are used.

Results and discussion

With this approach, the WSFP of primary aluminium has been calculated as follows:

• 18.2 m³ H₂Oe./tonne for global primary aluminium (GLO);
• 9.6 m³ H₂Oe/tonne for global primary aluminium, excluding China (RoW).

Conclusions

In order to avoid distorted results of water footprint studies, in depth analysis of identified hotspots in water consumption is necessary, in this case the plant-by plant approach, in accordance with ISO 14046. Data providers are encouraged to facilitate such analysis by improving the accessibility of such detailed data.

     

作物水分供应订正函数的韦伯函数型

从作物水分生产潜力、潜在水分利用效率与水分满足率的关系及特点入手,引入水分供应订正函数的韦伯形式。与目前常见的水分供应订正函数形式相比,本文给出的韦伯形式的水分供应订正函数具有临界水分满足率和“旋回”特征,能较好地解释作物水分生产潜力与水分满足率之间的数量关系,模型的实用性较广。模型中位置参数表示临界水分满足率;尺度参数表示水分满足率的取值范围;形状参数决定水分供应订正函数的“峰度”和“偏斜度”。根据“图解法”可求取水分供应订正函数的相关参数。其参数也具有明确的生物学和物理学意义,参数值本身也较稳定,使模型在应用中可望具有良好的稳定性。     

Crystal structure of family 5 uracil-DNA glycosylase bound to DNA

Uracil-DNA glycosylase (UDG) removes uracil generated by the deamination of cytosine or misincorporation of deoxyuridine monophosphate. Within the UDG superfamily, a fifth UDG family lacks a polar residue in the active-site motif, which mediates the hydrolysis of the glycosidic bond by activation of a water molecule in UDG families 1-4. We have determined the crystal structure of a novel family 5 UDG from Thermus thermophilus HB8 complexed with DNA containing an abasic site. The active-site structure suggests this enzyme uses both steric force and water activation for its excision reaction. A conserved asparagine residue acts as a ligand to the catalytic water molecule. The structure also implies that another water molecule acts as a barrier during substrate recognition. Based on no significant open-closed conformational change upon binding to DNA, we propose a "slide-in" mechanism for initial damage recognition.     

A simple moder for estimating the ice content of freezing ectotherms

1. 1.Although body ice content is an important variable affecting freeze tolerance, present calorimetric methods for its measurement necessarily require the termination of a freezing protocol.

2. 2.A simple iterative model, based on the colligative properties of solutions and requiring precise measurements of only equilibrium freezing point (of the unfrozen organism) and of core body temperature, allows estimation of the percentage of body water frozen at any time during a freezing episode.

3. 3.This model can also predict the lethal temperature for a freezing ectotherm, assuming that death occurs due to osmotic dehydration when 67% (of any other known lethal fraction) of the body water is frozen.

4. 4.The basic model is easily extended to evaluate the effects of variables such as: body mass, initial body water content, initial osmotic concentration, and test chamber microenvironment.

5. 5.This model is not intended to supplant existing more exact biophysical models of freezing kinetics. Rather it is proposed as a first approximation which is generally supported by published data and which should be of significant practical value for investigators of freeze tolerant organisms.

Effects of initial density,nutrient, and water level regime on the seedling survival and growth of <Emphasis Type="Italic">Typha orientalis</Emphasis> Presl

Seedlings’ successful establishment is of importance in the preemption process of pioneers in wetlands. Although Typha orientalis Presl has been reported as a pioneer in Asia countries, studies on the seedling phase of T. orientalis are not available yet. A mesocosm experiment was conducted to understand the effects of biotic (initial density) and abiotic (nutrient and water level regime) factors on the seedling survival and growth of T. orientalis. Most seedlings survived under low initial density (93.8%) and eutrophic (95.5%) rather than high initial density (64.3%) and ombrotrophic (62.5%). Seedlings under low initial density, eutrophic, and flooded conditions showed relatively higher growth in shoot height. The final number of ramets showed an adverse tendency compared to the survival rate and shoot height particularly depending on the water level regime. T. orientalis compensated its biomass production with producing less but longer shoots under the flooded condition, indicating the phenotypic plasticity of T. orientalis as a deep water species. However, the compensation seemed to be guaranteed only under the condition of sufficient nutrients. Asian T. orientalis seemed not to be a pioneer but a weak-competitor not only in mature plant stage but also in juvenile seedling stage unless sufficient nutrients are guaranteed.     

Is the Volume-Regulated Anion Channel VRAC a “Water-Permeable” Channel?

The volume-regulated anion channel, VRAC, plays an important role in cell volume regulation. This channel is permeable for a wide variety of anions, amino acids, and organic osmolytes, including taurine. However, nothing is known about possible water permeability of this channel. Water permeability of endothelial cells is estimated from the initial rate of cell swelling because of a hypotonic challenge. As a result of simultaneous volume and current measurements, it will be shown that water permeability is decreased by inhibition of VRAC. It is concluded that water permeates VRAC and might be able to accelerate water transport by providing an additional permeation pathway for water. Therefore VRAC can be considered as a water-permeable, "wet" channel.     

Correlation of water translocation,cuticle dehydration and post-ecdysial sclerotization by the american cockroach

• 1.1. Haemolymph volume decreases during the initial 16 hr post-ecdysial period, increases after water ingestion and subsequently drops until the inter-ecdysial level is reached.
• 2.2. Total body water follows a similar pattern, but the changes are not as pronounced.
• 3.3. Tissue water is inversely proportional to the total body water.
• 4.4. Soluble cuticle protein declines throughout the initial 16 hr period while both β-glucosidase and alkaline phosphatase activity is lost within 6 hr after ecdysis.
• 5.5. Dehydration of the cuticle also occurs during the immediate 6 hr post-ecdysial period.
• 6.6. These data suggest that the formation of the protein-insoluble matrix is linked with water loss.
• 7.7. Water removal may decrease the distance between molecules allowing specific reactions to take place.

     

Growth of Aeromonas hydrophila at Low Concentrations of Substrates Added to Tap Water

The ability of an Aeromonas hydrophila isolate obtained from filtered river water to grow at low substrate concentrations was studied in batch experiments with tap water supplied with low concentrations of substrates. Growth was assessed by colony count determinations. The isolate only multiplied in the used tap water (2 to 3 mg of dissolved organic carbon per liter) after the addition of a small amount of an assimilable carbon compound. d-Glucose especially caused growth of the organism even at initial concentrations below 10 mug of C per liter. At initial glucose concentrations below the K(s) value (12 mug of C per liter), generation times and yield (colony-forming units per milligram of substrate-C) were nonlinear with 1/initial glucose concentrations and initial glucose concentrations, respectively. From these observations, the maintenance coefficient m was calculated (m = 0.015 mg of glucose per mg [dry wt] per h at 12 degrees C). At initial concentrations below the K(s) value of starch (73 mug of C per liter), no growth was observed, but complete use of starch occurred in these situations after the addition of 10 mug of glucose-C per liter. The results of this study show that information of ecological significance may be obtained by very simple batch experiments. Moreover, the isolate studied may be used in growth experiments to assess the maximum concentration of glucose which might be present in water, particularly tap water.