Comparison of saccharification process by acid and microwave-assisted acid pretreated swine manure

The saccharification process of swine manure by conventional and microwave-assisted acid pretreated were investigated using cellulose enzymes, respectively. The optima for microwave-assisted acid pretreated swine manure is achieved when swine manure of 50 g l⁻¹ of substrate concentration and water amount 40 ml was pretreated by 4% H₂SO₄ concentration with 445 W microwave powers for 30 min at pretreatment period, and temperature 50 °C, enzyme loading 2 mg g⁻¹ substrate, substrate concentration 5 g l⁻¹ and initial medium pH 4.8 at enzymes hydrolysis period by microwave-assisted acid pretreated, respectively. The optimal conditions by conventional acid pretreated is obtained when 50 g l⁻¹ swine manure was submerged in 40 ml, 4% H₂SO₄ maintained at 130 °C for 3 h at pretreatment period, and temperature 45 °C, enzyme loading 2 mg g⁻¹ substrate, substrate concentration 15 g l⁻¹ and initial medium pH 5.2 at enzymes hydrolysis period, respectively. Under the optimum conditions microwave-assisted acid pretreatment could achieve higher yield of reducing sugar, short reaction time, and lower energy consumption than from the conventional acid pretreatment, which indicates that microwave-assisted acid pretreatment is more suitable for swine manure pretreatment than by acid alone.     

Effect of bulk liquid BOD concentration on activity and microbial community structure of a nitrifying,membrane-aerated biofilm

Membrane-aerated biofilms (MABs) are an effective means to achieve nitrification and denitrification of wastewater. In this research, microsensors, fluorescence in situ hybridization (FISH), and modeling were used to assess the impact of bulk liquid biological oxygen demand (BOD) concentrations on the activity and microbial community structure of nitrifying MABs. With 1 g m⁻³ BOD in the bulk liquid, the nitrification rate was 1.3 g N m⁻² day⁻¹, slightly lower than the 1.5 g N m⁻² day⁻¹ reported for no bulk liquid BOD. With bulk liquid BOD concentrations of 3 and 10 g m⁻³, the rates decreased to 1 and 0.4 g N m⁻² day⁻¹, respectively. The percent denitrification increased from 20% to 100% when the BOD increased from 1 to 10 g m⁻³ BOD. FISH results indicated increasing abundance of heterotrophs with increasing bulk liquid BOD, consistent with the increased denitrification rates. Modeling was used to assess the effect of BOD on nitrification rates and to compare an MAB to a conventional biofilm. The model-predicted nitrification rates were consistent with the experimental results. Also, nitrification in the MAB was much less sensitive to BOD inhibition than the conventional biofilm. The MAB achieved concurrent nitrification and denitrification, whereas little denitrification occurred in the conventional biofilm.     

Disuse-related decline in trabecular bone structure

Sedentary life style may degrade bone mass and microstructure resulting in osteoporosis. We characterized trabecular bone structural properties to determine if the LRP5 G171V mutation will protect against disuse-related bone loss. Forty-eight adult male mice representing three genotypes (WT = wild type, KO = LRP5-knockout +/−, HBM = High bone with the LRP5 G171V mutation) were each randomly divided between control and disuse (4 week hindlimb suspension) groups. Trabecular bone volume fraction (BV/TV) declined in all the three genotypes. Trabecular thickness was lower in the HBM and LRP5 (+/−) KO disuse groups when compared to their respective controls. While the remaining measures of bone structure (Trabecular number, connectivity density, apparent and tissue density) were lower, the trabecular separation increased in the LRP5 (+/−) with disuse. Although the absolute loss in BV/TV was similar, the relative loss due to disuse was far greater in the LRP5 (+/−) mice (67%) than in the HBM mice (14%). The disuse caused 20% decrease in trabecular number and thickness for LRP5 (+/−), while the decline was between 6 and 11% for the HBM and WT mice.     

A Laser Structure Based on Metal-Dielectric-Metal Plasmonic Nanocavity

A subwavelength plasmonic laser structure based on a metal-dielectric-metal nanocavity is proposed and numerically simulated by using the finite difference time domain method with perfectly matched layer absorbing boundary condition. The nanocavity model and gain analysis are respectively given. The simulation results show that the losses within the nanocavity (including surface plasmon losses) can be compensated by the gain material and the threshold gain of the laser is about 1.5 × 10³ cm⁻¹ with the peak wavelength around 1,550 nm. The new device would be an important step toward a fully integrated surface plasmon circuits.     

Predicting the status of wild deer as hosts of <Emphasis Type="Italic">Mycobacterium bovis</Emphasis> infection in Britain

Control of livestock diseases can become complicated when wild animals are involved. The Eurasian badger (Meles meles) is considered the principle wildlife host of Mycobacterium bovis (which causes bovine tuberculosis, bTB) in Great Britain and Ireland, but wild deer have also been implicated. Whether wild deer are likely to perpetuate bTB in cattle depends on the exposure risks they pose, the mode of pathogen transmission, the distances over which the disease can be transported and whether they can maintain infection within their own populations independently of other sources. We evaluated the likely host status of each of four species of wild British deer (red, roe, fallow and Reeves' muntjac) and the badger across a range of densities typically observed in Britain by manipulating the reproductive number equation proposed by Anderson and May (1991). We estimate that roe deer almost certainly act as spillover hosts at densities lower than 30 km⁻², red deer below 16 km⁻², muntjac below 6 km⁻², fallow below 4 km⁻² and the badger below 2 km⁻². We also estimate that muntjac will almost certainly act as maintenance hosts at densities above 56 km⁻², fallow above 47 km⁻² and badgers above 24 km⁻². For densities between these values, we cannot be certain of the host status of these species, and for red and roe deer we cannot be certain of host status under most natural conditions typically experienced in parts of Britain experiencing high incidence of bTB in cattle. However, enhanced transmission rates resulting from artificially high densities such as might be experienced at supplementary feeding sites may be sufficient to promote independent maintenance of infection. We were not able to confidently assign host status to any species over a wide range of densities, but conclude that this is likely to reflect reality, where host status may be affected as much by, for example, demographic fluctuations as it is by population density. Our results imply densities below which populations of wild deer inhabiting cattle bTB hotspots ought to be maintained in order to control the possibility of them perpetuating the cycle of intra- and interspecific M. bovis transmission.     

Microwave-assisted enzymatic synthesis of beef tallow biodiesel

Optimal conditions for the microwave-assisted enzymatic synthesis of biodiesel have been developed by a full 2² factorial design leading to a set of seven runs with different combinations of molar ratio and temperature. The main goal was to reduce the reaction time preliminarily established by a process of conventional heating. Reactions yielding biodiesel, in which beef tallow and ethanol used as raw materials were catalyzed by lipase from Burkholderia cepacia immobilized on silica-PVA and microwave irradiations within the range of 8–15 W were performed to reach the reaction temperature. Under optimized conditions (1:6 molar ratio of beef tallow to ethanol molar ratio at 50°C) almost total conversion of the fatty acid presented in the original beef tallow was converted into ethyl esters in a reaction that required 8 h, i.e., a productivity of about 92 mg ethyl esters g⁻¹ h⁻¹. This represents an increase of sixfold for the process carried out under conventional heating. In general, the process promises low energy demand and higher biodiesel productivity. The microwave assistance speeds up the enzyme catalyzed reactions, decreases the destructive effects on the enzyme of the operational conditions such as, higher temperature, stability, and specificity to its substrate, and allows the entire reaction medium to be heated uniformly.     

Direct electron transfer and electrochemical study of hemoglobin immobilized in ZnO hollow spheres

ZnO hollow spheres were firstly prepared. A new type of amperometric hydrogen peroxide biosensor was fabricated by entrapping Hemoglobin (Hb) through the ZnO hollow spheres (ZHS) nanoparticles. The composition morphology and size were studied by transmission electron microscopy. The surface topography of the prepared films was imaged by atomic force microscope (AFM). Several techniques, including UV–vis absorption spectroscopy, cyclic voltammetry, chronoamperometry were employed to characterize the performance of the biosensor. The results indicated that the ZHS nanoparticles had enhanced the performance of the hydrogen peroxide sensors. The electrochemical parameters of Hb in the ZHS were calculated by the results of the electron-transfer coefficient (α) and the apparent heterogeneous electron-transfer rate constant K _s as 0.5 and 3.1 s⁻¹, respectively. The resulting biosensors showed a wide linear range from 2.1 × 10⁻⁶ to 5.18 × 10⁻³ M, with a low detection limit of 7.0 × 10⁻⁷ M (S/N = 3) under optimized experimental conditions. The results demonstrated that the ZHS matrix may improve the protein loading with the retention of bioactivity and greatly promote the direct electron transfer, which can be attributed to its unique morphology, high specific surface area, and biocompatibility. The biosensor obtained from this study possesses high sensitivity, good reproducibility, and long-term stability.     

Age,growth, and population structure of the smooth clam <Emphasis Type="Italic">Callista chione</Emphasis> in the eastern Adriatic Sea

The age, growth, and population structure of the smooth clam Callista chione were determined from samples collected by hydraulic dredge and SCUBA at four locations in the eastern Adriatic during 2007 and 2008. The age of 436 clam shells was determined from internal growth lines present in shell sections, and the timing of growth line formation was ascertained from monthly collections of clams to occur between August and September when sea water temperatures were maximal. In addition, age of 30 older individuals was verified with acetate peels of polished and etched shell sections. Differences were apparent in the age structure and growth rates of clams collected from the four locations studied. Von Bertalanffy growth (VBG) curves obtained for clams from these locations were L _t  = 72.4 (1−e^{−0.25(t − 2.68)}) (Rab Island), L _t  = 74.5 (1−e^{−0.15(t + 0.57)}) (Pag Bay), L _t  = 79.3 (1−e^{−0.34(t − 0.97)}) (Cetina estuary), and L _t  = 82.5 (1−e^{−0.11(t + 2.88)}) (Kaštela Bay). The age of the clams ranged between 3 and 44 years; median clam ages were similar at three of the four locations (14, 12, and 12 years, respectively), but was significantly lower in the Cetina estuary (4 years). The VBG growth constants recorded from clams were within the range of values obtained for this species by previous authors. The observed local differences in population structure indicate different levels of exploitation and illustrate the need to establish long-term strategies for a sustainable exploitation of smooth clams in the Croatian Adriatic.     

Phytoplankton and primary production in clear-vegetated,inorganic-turbid,and algal-turbid shallow lakes from the pampa plain (Argentina)

Shallow lakes often alternate between two possible states: one clear with submerged macrophytes, and another one turbid, dominated by phytoplankton. A third type of shallow lakes, the inorganic turbid, result from high contents of suspended inorganic material, and is characterized by low phytoplankton biomass and macrophytes absence. In our survey, the structure and photosynthetic properties (based on ¹⁴C method) of phytoplankton were related to environmental conditions in these three types of lakes in the Pampa Plain. The underwater light climate was characterized. Clear-vegetated lakes were more transparent (K _d 4.5–7.7 m⁻¹), had high DOC concentrations (>45 mg l⁻¹), low phytoplankton Chl a (1.6–2.7 μg l⁻¹) dominated by nanoflagellates. Phytoplankton productivity and photosynthetic efficiency (α ~ 0.03 mgC mgChla ⁻¹ h⁻¹ W⁻¹ m²) were relatively low. Inorganic-turbid lakes showed highest K _d values (59.8–61.4 m⁻¹), lowest phytoplankton densities (dominated by Bacillariophyta), and Chl a ranged from 14.6 to 18.3 μg l⁻¹. Phytoplankton-turbid lakes showed, in general, high K _d (4.9–58.5 m⁻¹) due to their high phytoplankton abundances. These lakes exhibited the highest Chl a values (14.2–125.7 μg l⁻¹), and the highest productivities and efficiencies (maximum 0.56 mgC mgChla ⁻¹ h⁻¹ W⁻¹ m²). Autotrophic picoplankton abundance, dominated by ficocianine-rich picocyanobacteria, differed among the shallow lakes independently of their type (0.086 × 10⁵–41.7 × 10⁵ cells ml⁻¹). This article provides a complete characterization of phytoplankton structure (all size fractions), and primary production of the three types of lakes from the Pampa Plain, one of the richest areas in shallow lakes from South America. Handling editor: J. Padisak     

Non-parametric estimation of thresholds for radiation effects in vertebrate species under chronic low-LET exposures

Databases on effects of chronic low-LET radiation exposure were analyzed by non-parametric statistical methods, to estimate the threshold dose rates above which radiation effects can be expected in vertebrate organisms. Data were grouped under three umbrella endpoints: effects on morbidity, reproduction, and life shortening. The data sets were compiled on a simple ‘yes’ or ‘no’ basis. Each data set included dose rates at which effects were reported without further details about the size or peculiarity of the effects. In total, the data sets include 84 values for endpoint “morbidity”, 77 values for reproduction, and 41 values for life shortening. The dose rates in each set were ranked from low to higher values. The threshold TDR5 for radiation effects of a given umbrella type was estimated as a dose rate below which only a small percentage (5%) of data reported statistically significant radiation effects. The statistical treatment of the data sets was performed using non-parametric order statistics, and the bootstrap method. The resulting thresholds estimated by the order statistics are for morbidity effects 8.1 × 10⁻⁴ Gy day⁻¹ (2.0 × 10⁻⁴–1.0 × 10⁻³), reproduction effects 6.0 × 10⁻⁴ Gy day⁻¹ (4.0 × 10⁻⁴–1.5 × 10⁻³), and life shortening 3.0 × 10⁻³ Gy day⁻¹ (1.0 × 10⁻³–6.0 × 10⁻³), respectively. The bootstrap method gave slightly lower values: 2.1 × 10⁻⁴ Gy day⁻¹ (1.4 × 10⁻⁴–3.2 × 10⁻⁴) (morbidity), 4.1 × 10⁻⁴ Gy day⁻¹ (3.0 × 10⁻⁴–5.7 × 10⁻⁴) (reproduction), and 1.1 × 10⁻³ Gy day⁻¹ (7.9 × 10⁻⁴–1.3 × 10⁻³) (life shortening), respectively. The generic threshold dose rate (based on all umbrella types of effects) was estimated at 1.0 × 10⁻³ Gy day⁻¹.     

Brainstem Concentrations of Cholesterol are not Influenced by Genetic Ablation of the Low-Density Lipoprotein Receptor

Purpose The low-density lipoprotein receptor (LDLr) mediates the uptake of LDL particles enriched with cholesterol, into several tissues. In contrast to other tissues, the brain is thought to obtain cholesterol solely by de novo synthesis, yet certain brain regions such as the brainstem are highly enriched with the LDLr. The goal of the present study was to assess the role of the LDLr in maintaining cholesterol concentrations in the brainstem of wildtype and LDLr knockout (LDLr−/−) mice. Cholesterol concentrations were also measured in the cortex, which served as a reference point, due to the lower expression of the LDLr, as compared to the brainstem. Methods LDLr−/− and wildtype mice consumed an AIN-93G diet ad libitum until 7 weeks of age. After microwaving, the cortex and anterior brain stem were isolated for cholesterol analysis. Cholesterol was extracted into chloroform/methanol, derivatized in trimethylsilyl chloride and measured by gas chromatography/mass spectrometry. Results Concentrations of cholesterol in the brainstem did not differ statistically between LDLr−/− (18.8 ± 1.6 mg/g wet weight brain) and wildtype (19.1 ± 2.0). Cortical cholesterol concentrations also did not differ statistically between LDLr−/− (11.0 ± 0.4 mg/g wet weight brain) and wildtype (11.1 ± 0.2) mice. Conclusion The LDLr is not necessary for maintaining cholesterol concentrations in the cortex or brainstem, suggesting that other mechanisms are sufficient to maintain brain cholesterol concentrations.     

The influence of altitude and urbanisation on trends and mean dates in phenology (1980–2009)

Long-term studies on urban phenology using network data are commonly limited by the small number of observation sites within city centres. Moreover, cities are often located on major rivers and consequently at lower altitudes than their rural surroundings. For these reasons, it is important (1) to go beyond a plain urban–rural comparison by taking the degree of urbanisation into account, and (2) to evaluate urbanisation and altitudinal effects simultaneously. Temporal phenological trends (1980–2009) for nine phenological spring events centred on the German cities of Frankfurt, Cologne and Munich were analysed. Trends of phenological onset dates were negative (i.e. earlier onset in phenology) for 96% of the 808 time series and significantly negative for 56% of the total number. Mean trends for the nine phenological events ranged between −0.23 days year⁻¹ for beech and −0.50 days year⁻¹ for hazel. The dependence of these trends and of mean dates on altitude and on the degree of urbanisation was explored. For mean dates, we demonstrated an earlier phenological onset at lower altitude and with a higher degree of urbanisation: altitude effects were highly significant and ranged between 1.34 days (100 m)⁻¹ (beech) and 4.27 days (100 m)⁻¹ (hazel). Coefficients for the log-transformed urban index were statistically significant for five events and varied greatly between events (coefficients from −1.74 for spruce to −5.08 for hazel). For trends in phenology, altitude was only significant for Norway maple, and no urban effects were significant. Hence, trends in phenology did not change significantly with higher altitudes or urbanised areas.     

Poorly formed chloroplasts are barriers to successful interspecific hybridization in chickpea following in vitro embryo rescue

Albinism is viewed as a major experimental bottleneck during wide hybridization in several species; the phenomenon is also widely reported in androgenesis and doubled haploid cultures. In this study, when chickpea (Cicer arietinum) was crossed with distant wild relatives, C. judaicum and C. pinnatifidum, the only hybrid embryos that survived were those rescued using in vitro techniques. Fourteen to 21-day-old embryos were incubated in ML6 medium with 90 g l⁻¹ sucrose, 1 mg l⁻¹ zeatin and 0.25 mg l⁻¹ indole acetic acid. Germinating embryos were dissected from the ovule and transferred to fresh medium without growth regulators. Later, shoots were micropropagated on solid MS medium, supplemented with B5 vitamins, 30 g l⁻¹ sucrose, 0.1 mg l⁻¹ 6-benzyladenine and 0.01 mg l⁻¹ naphthaleneacetic acid. Although some post-hybridization barriers were overcome by rescue in vitro, regenerated hybrid plantlets failed to thrive in culture and few survived transfer to soil. Here we report findings from characterization of this valuable breeding material, as a step towards a better understanding of albinism in chickpea wide hybrids and other plant tissue cultures. Following proliferation, hybrids were phenotyped as green, pale green and albino. Genotype affected pod set, regeneration and albinism. Plastid ultrastructure studies using transmission electron microscopy revealed that thylakoid membranes were well-formed in green hybrids but not in albinos. Spectrophotometric analysis of chlorophyll a, chlorophyll b and total carotenoids revealed that chlorophyll content was three to fourfold lower in albino compared to green hybrids; moreover green hybrids had two to threefold lower total chlorophyll content than in vitro-grown plantlets of their parents. In contrast, carotenoids were higher in some albino phenotypes and lower in others; however overall differences in carotenoids were less marked between all genotypes compared to chlorophyll pigments. Genetic variability between different wide crosses provides an opportunity to select certain chickpea parents and wild species which give rise to more frequent green hybrid regenerants. In future, only these hybrids will be maintained and multiplied for transfer to the glasshouse in our program.     

Contributions of dust to phosphorus cycling in tropical forests of the Luquillo Mountains,Puerto Rico

The input of phosphorus (P) through mineral aerosol dust deposition may be an important component of nutrient dynamics in tropical forest ecosystems. A new dust deposition calculation is used to construct a broad analysis of the importance of dust-derived P to the P budget of a montane wet tropical forest in the Luquillo Mountains of Puerto Rico. The dust deposition calculation used here takes advantage of an internal geochemical signal (Sr isotope mass balance) to provide a spatially integrated longer-term average dust deposition flux. Dust inputs of P (0.23 ± 0.08 kg ha⁻¹ year⁻¹) are compared with watershed-average inputs of P to the soil through the conversion of underlying saprolite into soil (between 0.07 and 0.19 kg ha⁻¹ year⁻¹), and with watershed-average losses of soil P through leaching (between 0.02 and 0.14 kg ha⁻¹ year⁻¹) and erosion (between 0.04 and 1.38 kg ha⁻¹ year⁻¹). The similar magnitude of dust-derived P inputs to that of other fluxes indicates that dust is an important component of the soil and biomass P budget in this ecosystem. Dust-derived inputs of P alone are capable of completely replacing the total soil and biomass P pool on a timescale of between 2.8 ka and 7.0 ka, less than both the average soil residence time (~15 ka) and the average landslide recurrence interval (~10 ka).     

Microwave-induced synthesis of new optically active and soluble polyamides containing pendent 4-(2-phthalimidiylpropanoylamino)benzoylamino-groups

An aromatic chiral diacid monomer, 5-[4-(2-phthalimidiylpropanoylamino)-benzoylamino]isophthalic acid was synthesized in five steps under conventional heating in high yield and purity. A series of soluble, thermally stable and optically active polyamides (PA)s containing pendent groups made of phthalimide, flexible l-alanine and benzamide sequence have been successfully synthesized under microwave irradiation. Excellent yields and very short reaction time were the main characteristics of this method. The same polymerization reactions were also carried out by conventional thermal heating and the results are compared. The resulting PAs had inherent viscosity in the range of 0.50–0.79 dL g⁻¹. All of the these polymers are readily dissolved in various solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide and N,N-dimethylformamide and showed glass-transition temperature above 200°C. Thermogravimetric analysis demonstrated that the 10% weight-loss temperatures in nitrogen were 372 and 422°C for selected two PAs. All of these polymers showed optical rotation which is due to successful insertion of l-alanine in the structure of chiral diacid monomer.     

Response of Arbuscular Mycorrhizal Fungi on Wheat (Triticum aestivum L.) Grown Conventionally and on Beds in a Sandy Loam Soil

The present study was undertaken to assess the benefit and compare the functioning of AM fungi on wheat grown conventionally and on beds. Ten treatment combinations were used, treatments 1 and 2: no fertilizers with and without arbuscular mycorrhizal (AM) fungi (In vitro produced Glomus intraradices); 3:100% of recommended NPK: (120 kg ha⁻¹ N; 60 kg ha⁻¹ P; 50 kg ha⁻¹ K), and 4 and 5: 75% of recommended NPK dose with and without AM inoculation in a 5 × 2 split-plot design on wheat using conventional/flat system and elevated/raised bed system. The maximum grain yield (3.84 t ha⁻¹) was obtained in AM fungi inoculated plots of raised bed system applied with 75% NPK and was found higher (although non- significant) than the conventional (3.73 t ha⁻¹) system. The AM inoculation at 75% fertilizer application can save 8.47, 5.38 kg P and 16.95, 10.75 kg N ha⁻¹, respectively, in bed and conventional system. While comparing the yield response with 100% fertilizer application alone, AM inoculation was found to save 20.30, 15.79 kg P and 40.60, 31.59 kg N ha⁻¹, respectively, in beds and conventional system. Mycorrhizal inoculation at 75% NPK application particularly in raised bed system seems to be more efficient in saving fertilizer inputs and utilizing P for producing higher yield and growth unlike non-mycorrhizal plants of 100% P. Besides the yield, mycorrhizal plants grown on beds had higher AM root colonization, soil dehydrogenases activity, and P-uptake. The present study indicates that the inoculation of AM fungi to wheat under raised beds is better response (although non-significantly higher) to conventional system and could be adopted for achieving higher yield of wheat at reduced fertilizer inputs after field validation.     

Effects of acetylcholinesterase inhibitor paraoxon denote the possibility of non-quantal acetylcholine release in myocardium of different vertebrates

Effects of organophosphorous acetylcholinesterase inhibitor paraoxon were studied in the isolated atrial and ventricular myocardium preparations of a fish (cod), an amphibian (frog) and a mammal (rat) using the microelectrode technique. Incubation of isolated atrium with paraoxon (5 × 10⁻⁶–5 × 10⁻⁵ M) caused significant reduction of action potential duration and marked slowing of sinus rhythm. These effects were abolished by muscarinic blocker atropine and therefore are caused by acetylcholine, which accumulates in the myocardium due to acetylcholinesterase inhibition even in the absence of vagal input. Hemicholinium III is a blocker of high affinity choline-uptake transporters, which are believed to mediate non-quantal release of acetylcholine from cholinergic terminals in different tissues. In the atrial myocardium of all the three studied species, hemicholinium III (10⁻⁵ M) significantly suppressed all the effects of paraoxon. Blocker of parasympathetic ganglionic transmission hexamethonium bromide (10⁻⁴ M) and inhibitor of vesicular acetylcholine transporters vesamicol (10⁻⁵ M) failed to attenuate paraoxon effects. Among ventricular myocardium preparations of three species paraoxon provoked marked cholinergic effects only in frog, hemicholinium III abolished these effects effectively. We conclude that paraoxon stops degradation of acetylcholine in the myocardium and helps to reveal the effects of acetylcholine, which is continuously secreted from the cholinergic nerves in non-quantal manner. Thus, non-quantal release of acetylcholine in the heart is not specific only for mammals, but is also present in the hearts of different vertebrates.     

Haplotypes of IL-10 promoter variants are associated with susceptibility to severe malarial anemia and functional changes in IL-10 production

Plasmodium falciparum malaria is one of the leading global causes of morbidity and mortality with African children bearing the highest disease burden. Among the various severe disease sequelae common to falciparum malaria, severe malarial anemia (SMA) in pediatric populations accounts for the greatest degree of mortality. Although the patho-physiological basis of SMA remains unclear, dysregulation in inflammatory mediators, such as interleukin (IL)-10, appear to play an important role in determining disease outcomes. Since polymorphic variability in innate immune response genes conditions susceptibility to malaria, the relationship between common IL-10 promoter variants (−1,082A/G, −819T/C, and −592A/C), SMA (Hb < 6.0 g/dL), and circulating inflammatory mediator levels (i.e., IL-10, TNF-α, IL-6 and IL-12) were investigated in parasitemic Kenyan children (n = 375) in a holoendemic P. falciparum transmission area. Multivariate logistic regression analyses demonstrated that the −1,082G/−819C/−592C (GCC) haplotype was associated with protection against SMA (OR; 0.68, 95% CI, 0.43–1.05; P = 0.044) and increased IL-10 production (P = 0.029). Although none of the other haplotypes were significantly associated with susceptibility to SMA, individuals with the −1,082A/−819T/−592A (ATA) haplotype had an increased risk of SMA and reduced circulating IL-10 levels (P = 0.042). Additional results revealed that the IL-10:TNF-α ratio was higher in the GCC group (P = 0.024) and lower in individuals with the ATA haplotype (P = 0.034), while the IL-10:IL-12 ratio was higher in ATA haplotype (P = 0.006). Results presented here demonstrate that common IL-10 promoter haplotypes condition susceptibility to SMA and functional changes in circulating IL-10, TNF-α, and IL-12 levels in children with falciparum malaria. The study was approved by the ethical and scientific review committees at the Kenya Medical Research Institute and the institutional review board at the University of Pittsburgh.     

Seasonal dynamics of soil CO<Subscript>2</Subscript> efflux in a conventional tilled wheat field of the Loess Plateau,China

An automated chamber system was employed to measure the soil CO₂ efflux (SCE) in situ for 2 years in a conventional wheat field of the Loess Plateau, China under semi-arid conditions. The annual mean SCE values were 2.44 ± 2.52 μmol m⁻² s⁻¹ in 2006 and 2.37 ± 2.33 μmol m⁻² s⁻¹ in 2007. Distinct seasonality in the SCE was observed, with significant differences occurring among four periods divided by harvesting, tillage and sowing. In the period from tillage to sowing, the mean SCE values were 2.82 and 2.69 times the annual mean values in 2006 and 2007, respectively, and SCE accounted for 39% and 48% of the annual total within 14% and 18% of the days of the years. Although there were significant exponential correlations between the SCE and soil temperature, and significant linear correlations between the SCE and soil moisture for measurements conducted in the periods before tillage and after sowing each year, the SCE from tillage to sowing was significantly beyond the correlation curves. These findings indicated that seasonal variation in the SCE in a conventional field was controlled not only by soil temperature and moisture, but also by tillage practice. The confounding effects of climate and practice on SCE should be considered when developing ways to mitigate soil carbon loss in conventional cropland in semi-arid regions.     

Molecular prediction of oseltamivir efficiency against probable influenza A (H1N1-2009) mutants: molecular modeling approach

To predict the susceptibility of the probable 2009 influenza A (H1N1-2009) mutant strains to oseltamivir, MD/LIE approach was applied to oseltamivir complexed with the most frequent drug-resistant strains of neuraminidase subtypes N1 and N2: two mutations on the framework residues (N294S and H274Y) and the two others on the direct-binding residues (E119V and R292K) of oseltamivir. Relative to those of the wild type (WT), loss of drug–target interaction energies, especially in terms of electrostatic contributions and hydrogen bonds were dominantly established in the E119V and R292K mutated systems. The inhibitory potencies of oseltamivir towards the WT and mutants were predicted according to the ordering of binding-free energies: WT (−12.3 kcal mol⁻¹) > N294S (−10.4 kcal mol⁻¹) > H274Y (−9.8 kcal mol⁻¹) > E119 V (−9.3 kcal mol⁻¹) > R292K (−7.7 kcal mol⁻¹), suggesting that the H1N1-2009 influenza with R292K substitution, perhaps, conferred a high level of oseltamivir resistance, while the other mutants revealed moderate resistance levels. This result calls for an urgent need to develop new potent anti-influenza agents against the next pandemic of potentially higher oseltamivir-resistant H1N1-2009 influenza.