Physiological and Biochemical Mechanisms Preventing Cd Toxicity in the New Hyperaccumulator <Emphasis Type="Italic">Abelmoschus manihot</Emphasis>

Abelmoschus manihot, an ornamental plant, was examined for phytoremediation purposes in accordance with the ability to accumulate cadmium and physiological mechanisms of cadmium tolerance. A net photosynthetic rate (A _N) glasshouse experiment for 60 days was conducted to investigate the influence of different cadmium amounts (0–100 mg kg^?1) on the growth, biomass, photosynthetic performance, reactive oxygen species (ROS) production, antioxidative enzyme activities, Cd uptake and accumulation of A. manihot. Exposure to cadmium enhanced plant growth even at 100 mg kg^?1, without showing symptoms of visible damage. The cadmium concentration of shoots (stems or leaves) and roots was more than the critical value of 100 mg kg^?1 and reached 126.17, 185.26 and 210.24 mg kg^?1, respectively. BCF values of A. manihot plants exceeded the reference value 1.0 for all the Cd treatments, and TF values were greater than 1 at 15–60 mg kg^?1 Cd treatment. The results also showed that cadmium concentrations of 60 mg kg^?1 or less induced a significant enhancement in plant net photosynthetic rate (A _N), stomatal conductance (G _s), transpiration rate (T _r), photosynthetic pigments and F _v/F _m. These parameters were slightly decreased at the higher concentration (100 mg kg^?1). The ROS production (O₂ ^?, H₂O₂) and antioxidative response including SOD, CAT and POD were significantly enhanced by increasing cadmium. These results suggest that A. manihot can be considered as a Cd-hyperaccumulator and the hormetic effects may be taken into consideration in remediation of Cd contamination soil.     

<Emphasis Type="Italic">In vitro</Emphasis> and <Emphasis Type="Italic">In vivo</Emphasis> Studies on a Novel Bioadhesive Colloidal System: Cationic Liposomes of Ibuprofen

The objective of this study was to develop an ocular drug delivery system built on the cationic liposomes, a novel bioadhesive colloidal system, which could enhance the precorneal residence time, ocular permeation, and bioavailability of ibuprofen. The optimal formulation of cationic liposomes prepared by ethanol injection method was ultimately confirmed by an orthogonal L₉ (3³) test design. In addition, γ-scintigraphic technology and the microdialysis technique were utilized in the assessment of in vivo precorneal retention capability and ocular bioavailability individually. In the end, we acquired the optimal formulation of ibuprofen cationic liposomes (Ibu-CL) by orthogonal test design, and the particle size and entrapment efficiency (EE%) were 121.0 ± 3.5 nm and 72.9 ± 3.4%, respectively. In comparison to ibuprofen eye drops (Ibu-ED), Ibu-CL could significantly prolong the T _max to 100 min and the AUC to 1.53-folds, which indicated that the Ibu-CL could improve the precorneal retention time and bioavailability of ibuprofen. Consequently, these outcomes designated that the ibuprofen cationic liposomes we researched probably are a promising application in ocular drug delivery system.     

Quantification of algal biofilms colonising building materials: chlorophyll a measured by PAM-fluorometry as a biomass parameter

Abstract

The aim of this study was to quantify algal colonisation on anthropogenic surfaces (viz. building facades and roof tiles) using chlorophyll a (chl a) as a specific biomarker. Chl a was estimated as the initial fluorescence F₀ of ‘dark adapted’ algae using a pulse-modulated fluorometer (PAM-2000). Four isolates of aeroterrestrial green algae and one aquatic isolate were included in this study. The chl a concentration and F₀ showed an exponential relationship in the tested range between 0 and 400 mg chl a m^?2. The relationship was linear at chl a concentrations <20 mg m^?2. Exponential and linear models are presented for the single isolates with large coefficients of determination (exponential: r² > 0.94, linear: r² > 0.92). The specific power of this fluorometric method is the detection of initial algal colonisation on surfaces in thin or young biofilms down to 3.5 mg chl a m^?2, which corresponds to an abundances of the investigated isolates between 0.2 and 1.5 million cells cm^?2.     

Fourteen Annually Repeated Droughts Suppressed Autotrophic Soil Respiration and Resulted in an Ecosystem Change

Predictions of future climate over the next 100 years show that the frequency of long periods of droughts in summer will increase in the Netherlands. This study investigated the effect of 14 annually repeated droughts on soil respiration at a Dutch heathland. Field measurements of total soil respiration (R_S) and microbial respiration (R_H) were modeled to determine annual C losses and to derive root respiration (R_A) C losses. The application of repeated droughts resulted in suppression of the total soil C loss from 392 to 332 g C m^?2 year^?1 in 2010–2011 and from 427 to 358 g C m^?2 year^?1 in 2011–2012. The R_H was the greatest contributor to heathland soil C loss (74–76%) and this was suppressed when directly exposed to drought conditions, although not significantly reduced on an annual basis. Annual R_A was suppressed by 42% (2010–2011) and 45% (2011–2012) under repeated drought, indicating there was a greater effect of the repeated annual drought in roots than in microbes. Field observations of photosynthesis (P_G) showed paradoxical results, with significantly greater ecosystem P_G on the drought treatment than the control treatment. Inclusion of plant activity (P_G) as a variable did not improve the fit of the models used in this study. However, other changes in plant composition and structure, such as increasing moss cover on the drought treatment, were noted to have occurred during the 14 years of annually repeated drought and these long term trends may help explain the effects of climate change (drought) on soil processes.     

Comparison of molecular genetic utilities of TD,AFLP, and MSAP among the accessions of <Emphasis Type="Italic">japonica,indica</Emphasis>, and <Emphasis Type="Italic">Tongil</Emphasis> of <Emphasis Type="Italic">Oryza sativa</Emphasis> L.

Rice is one of the most important food crops in the world. Genetic diversity is essential for cultivar improvement programs. We compared genetic diversity derived from insertion–deletion (in–del) or base substitutions by amplified fragment length polymorphism (AFLP), from transposon transposition mutations by transposon display (TD), and from cytosine methylation by methylation-sensitive amplified polymorphism (MSAP) in japonica, indica, and Tongil type varieties of Oryza sativa L. Polymorphic profiles from the three marker systems allowed us to clearly distinguish the three types of varieties. The indica type varieties showed the highest genetic diversity followed by the Tongil and japonica type varieties. Of the three marker systems, TD produced the highest marker indices, and AFLP and MSAP produced similar marker indices. Pair-wise comparisons of the three marker systems showed that the correlation between the two genetic markers systems (AFLP and TD, r = 0.959) was higher than the correlations between the genetic and epigenetic marker systems (AFLP and MSAP, r = 0.52; TD and MSAP, r = 0.505). Both genetic marker systems had similar levels of gene differentiation (G _ST ) and gene flow (N _m ), which differed in the epigenetic marker system. Although the G _ST of the epigenetic marker system was lower than the genetic marker systems, the N _m of the epigenetic marker system was higher than in the genetic marker systems, indicating that epigenetic variations have a greater influence than genetic variations among the O. sativa L. types.     

Impact of elevated CO<Subscript>2</Subscript> in <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> rooted stem cuttings inoculated with <Emphasis Type="Italic">Frankia</Emphasis>

Impact of different levels of elevated CO ₂ on the activity of Frankia (Nitrogen-fixing actinomycete) in Casuarina equisetifolia rooted stem cuttings has been studied to understand the relationship between C. equisetifolia, Frankia and CO₂. The stem cuttings of C. equietifolia were collected and treated with 2000 ppm of Indole Butyric Acid (IBA) for rooting. Thus vegetative propagated rooted stem cuttings of C. equisetifolia were inoculated with Frankia and placed in the Open top chambers (OTC) with elevated CO₂ facilities. These planting stocks were maintained in the OTC for 12 months under different levels of elevated CO₂ (ambient control, 600 ppm, 900 ppm). After 12 months, the nodule numbers, bio mass, growth, and photosynthesis of C. equisetifolia rooted stem cuttings inoculated with Frankia were improved under 600 ppm of CO₂. The rooted stem cuttings of C. equisetifolia inoculated with Frankia showed a higher number of nodules under 900 ppm of CO₂ and cuttings without Frankia inoculation exhibited poor growth. Tissue Nitrogen (N) content was also higher under 900 ppm of CO₂ than ambient control and 600 ppm levels. The photosynthetic rate was higher (17.8 μ mol CO₂ m^?2 s^?1) in 900 ppm of CO₂ than in 600 ppm (13.2 μ mol CO₂ m^?2 s^?1) and ambient control (8.3 μ mol CO₂ m^?2 s^?1). This study showed that Frankia can improve growth, N fixation and photosynthesis of C. equietifolia rooted stem cuttings under extreme elevated CO₂ level conditions (900 ppm).     

Tissue distribution of EDTA encapsulated within liposomes containing glycolipids or brain phospholipids

Multilamellar liposomes were prepared with various asialoglycolipids, gangliosides, sialic acid, or brain phospholipids in the liposome membrane and with ethylenediaminetetraacetic acid (EDTA) encapsulated in the aqueous compartments. The liposomes containing glycolipids or sialic acid were prepared from a mixture of phosphatidylcholine, cholesterol, and one of the following test substances: galactocerebroside, glucocerebroside, galactocerebroside sulfate, mixed gangliosides, monosialoganglioside G_M1, monosialoganglioside G_M2, monosialoganglioside G_M3, disialoganglioside G_D1a, or sialic acid. The liposomes containing brain phospholipids were mixtures of either sphingomyelin and cholesterol or a brain total phospholipid extract and cholesterol. Distribution of ¹⁴C-labeled EDTA were determined in mouse tissues from 15 min to 6 h or 12 h after a single injection of liposome prepartion. Liver uptake of encapsulated EDTA was lowest from all liposome preparations containing sialic acid or sialogangliosides regardless of the amount of sialic acid moiety present or the identity of the particular ganglioside; highest uptake of encapsulated EDTA by liver was from the liposomes containing galactocerebroside or brain phospholipids. Lungs and brain took up the largest amounts of EDTA from liposomes containing sphingomyelin and lesser amounts from liposomes containing G_D1a. Use of mouse brain phospholipid extract to prepare liposomes did not increase uptake of encapsulated EDTA by the brain. EDTA in liposomes containing monosialogangliosides, brain phospholipids, galactocerebroside, or sialic acid was taken up well by spleen and marrow. Highest thymus uptake of encapsulated EDTA was from liposomes containing G_D1a. These results demonstrate that inclusion of sialogangliosides in liposome membranes decreases uptake of liposomes by liver, thus making direction of encapsulated drugs to other organs more feasible. Liposomes containing glycolipids also have potential uses as probes of cell surface receptors.     

Assessment of the potential uses of liposomes for lymphoscintigraphy and lymphatic drug delivery failure of 99m-technetium marker to represent intact liposomes in lymph nodes

The in vivo fate of subcutaneously injected neutral SUV liposomes in rats was examined using a membrane marker, ^99mTc, and an aqueous marker, ¹²⁵I-labelled poly(vinyl pyrrolidone). Liposomes with entrapped ¹²⁵I-labelled poly(vinyl pyrrolidone) were labelled with ^99mTc by the SnCl₂ method [2]. ^99mTc-radioactivity was localized several-fold more in the primary and secondary regional lymph nodes than ¹²⁵I-labelled poly(vinyl pyrrolidone)-radioactivity. Similarly, ^99mTc-radioactivity appeared and was subsequently cleared from the circulation much more rapidly than ¹²⁵I-labelled poly(vinyl pyrrolidone). The gel chromatography of the lymph node homogenate revealed that 60–70% of ¹²⁵I-labelled poly(vinyl pyrrolidone)-radioactivity was in the liposome fractions, whereas only 3% of ^99mTc-radioactivity was co-eluted with liposomes. Thus, the two markers have different fates in the lymphatics, and the presence of all ^99mTc-radioactivity does not represent the 60–70% of intact liposomes present in lymph nodes. Using the aqueous marker ¹²⁵I-labelled poly(vinyl pyrrolidone), the lymphnode localization of positive, negative and neutral small unilamellar vesicles was studied, and it was found that ¹²⁵I-radioactivity was more localized from negative liposomes than from positive liposomes, which in turn was more localized than that from neutral liposomes. Thus, these findings differ from those reported earlier [2], where the authors used ^99mTc as a liposomal marker. In vitro studies showed that liposomes of preparations containing 20 mol% cholesterol became ‘leaky’ to low-molecular-weight drugs, for example, methotrexate (M_r 454) to a much greater extent than with a large-molecular-weight substance, ¹²⁵I-labelled poly(vinyl pyrrolidone) (M_r 30 000–40 000), when incubated with rat lymph at 37°C. Using the two markers ^99mTc and ¹²⁵I-labelled poly(vinyl pyrrolidone) it was found that the localization of both radioactivities was reduced in lymph nodes draining λ-carrageenan-treated footpads. In conclusion, it is suggested that liposomes can be used for the delivery of drugs to diseased lymph nodes, and it would be worthwhile examining the possibilities of using alternative methods of labelling liposomes with ^99mTc rather than using the SnCl₂ technique [2], or using other radionuclides as markers for γ-scan imaging.     

Antioxidant activity and absorption of cyanidin-3-O-glucoside liposomes in GES-1 cells in vitro

ABSTRACT

The use of anthocyanins are limited by their chemical properties. Recent evidence suggests Cyanidin-3-O-glucoside (C3 G) liposomes via the ethanol injection method exhibit improved stability. In the current study, the characterization and cell absorption of C3 G liposomes were explored via transmission electron microscopy and flow cytometry. The internalization of the C3 G liposomes across the gastric epithelial cell monolayer (GES-1 cells) were investigated. Results showed that the particle size and encapsulation efficiency were 234 ± 9.35 nm and 75.0% ± 0.001, respectively. The total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content were used to evaluate the antioxidant activity of C3 G liposomes. The C3 G liposomes can obviously increased T-AOC and decreased the MDA content.Collectively, C3 G liposomes protected human GES-1 cells from gastric mucosal injury induced by H₂O₂ by activating the related antioxidant pathway. Our research could provide a new effective treatment strategy for the absorption of stomach drugs.

Abbreviations: C3G: Cyanidin-3-O-glucoside; LP: Liposome; GES-1 cells: Human gastric epithelial cell lines; FBS: Fetal Bovine Serum; PBS: Phosphate-buffered saline; PC: Phosphatidylcholine; CH: Cholesterol; MDA: Malondialdehyde; TEM: Transmission electron microscope; FCM: Flow cytometry; FITC: Fluorescein isothiocyanate; DAPI: 4′, 6-diamidino-2phenylidole; FT-IR: Fourier Transform infrared spectroscopy; PFA: Paraformaldehyde     

Pharmacophore mapping,molecular docking and QSAR studies of structurally diverse compounds as CYP2B6 inhibitors

Pharmacophore mapping, molecular docking and quantitative structure–activity relationship (QSAR) studies were carried out for a structurally diverse set of 48 compounds as CYP2B6 inhibitors. The generated best pharmacophore hypotheses from the three methods of conformer generation (FAST, BEST and conformer algorithm based on energy screening and recursive buildup) indicate the importance of two features, namely, hydrogen bond acceptor [electron-rich centre] and ring aromaticity. The distance between the two centres of the important features for ideal inhibitors varied from 5.82 to 6.03 Å. The chemometric tools used for the QSAR analysis were genetic function approximation (GFA) and genetic partial least squares. The developed QSAR models indicate the importance of an electron-rich centre, size of molecule, impact of branching and ring system and distribution of charges in the molecular surface. The docking study confirms the importance of an electron-rich centre for binding with the iron atom of the cytochrome enzyme. A GFA model with spline option was found to be the best model based on internal validation as well as the r ² _{m (overall)} criterion (Q ² = 0.772, r ² _{m (overall)} = 0.774). According to the external prediction statistics (R ² _pred = 0.876), another GFA-derived model with spline option outperforms the remaining models.     

Cloning,expression, and characterization of a thermostable glucose-6-phosphate dehydrogenase from <Emphasis Type="Italic">Thermoanaerobacter tengcongensis</Emphasis>

Glucose-6-phosphate dehydrogenases (G6PDs) are important enzymes widely used in bioassay and biocatalysis. In this study, we reported the cloning, expression, and enzymatic characterization of G6PDs from the thermophilic bacterium Thermoanaerobacter tengcongensis MB4 (TtG6PD). SDS-PAGE showed that purified recombinant enzyme had an apparent subunit molecular weight of 60 kDa. Kinetics assay indicated that TtG6PD preferred NADP⁺ (k _cat/K _m = 2618 mM^?1 s^?1, k _cat = 249 s^?1, K _m = 0.10 ± 0.01 mM) as cofactor, although NAD⁺ (k _cat/K _m = 138 mM^?1 s^?1, k _cat = 604 s^?1, K _m = 4.37 ± 0.56 mM) could also be accepted. The K _m values of glucose-6-phosphate were 0.27 ± 0.07 mM and 5.08 ± 0.68 mM with NADP⁺ and NAD⁺ as cofactors, respectively. The enzyme displayed its optimum activity at pH 6.8–9.0 for NADP⁺ and at pH 7.0–8.6 for NAD⁺ while the optimal temperature was 80 °C for NADP⁺ and 70 °C for NAD⁺. This was the first observation that the NADP⁺-linked optimal temperature of a dual coenzyme-specific G6PD was higher than the NAD⁺-linked and growth (75 °C) optimal temperature, which suggested G6PD might contribute to the thermal resistance of a bacterium. The potential of TtG6PD to measure the activity of another thermophilic enzyme was demonstrated by the coupled assays for a thermophilic glucokinase.     

Effects of 5-aminolevulinic acid on Swiss chard (Beta vulgaris L. subsp. cicla) seedling growth under saline conditions

Salinity is a widespread adverse environmental problem globally, and significantly limits crop production. In this study, the possibility of enhancing salinity stress tolerance of Swiss chard (Beta vulgaris L. var. cicla) by 5-aminolevulinic acid (ALA) foliar application was investigated. The Swiss chard plants were grown in hydroponic culture. Twelve-week-old uniform seedlings were treated by 0 and 40 mM saline regimes generated by the mixture of sodium chloride and sodium sulfate (molar ratio NaCl:Na₂SO₄ = 9:1), and were foliar-sprayed with 0 and 60 μM L^?1 ALA (every 3 days) for 6 days; then the plants were treated for another 7 days (every 3 day) with increased concentration of salinity and ALA, 80 mM and 120 μM L^?1. Salinity without ALA application significantly decreased plant growth [43 % in shoot dry weight (DW), 21 % in root DW, 24 % in relative growth rate (RGR), 43 % in leaf area (LA)], water uptake [20.8 % in relative water content (RWC), 47.9 % in osmotic potential (OP)], chlorophyll (Chl) a content (10 %), P_n (36 %), G_s (72 %) and T_r (59 %) compared with those in control plants; however, under saline conditions, ALA foliar application improved plant growth (49.7 % in shoot DW, 27 % in root DW, 42.3 % in RGR, 72.1 % in LA) and increased RWC (12 %), Chl a content (10 %) and photosynthetic parameters (27 % in P_n, 28 % in G_s, 14 % in T_r) compared with those in untreated plants. Salinity significantly increased Na⁺ content, resulting in the reduction of Mg²⁺ and K⁺ contents. ALA foliar application alleviated ionic toxicity through the reduction of Na⁺ content and Na⁺/K⁺ ratio. On the other hand, it increased total nitrogen and glycine betaine (GB) content. ALA foliar application slightly reduced malondialdehyde (MDA) content, indicating that ALA has the potential to alleviate oxidative stress in salinity-stressed Swiss chard.     

Induced change in <Emphasis Type="Italic">Arthrospira</Emphasis> sp. (<Emphasis Type="Italic">Spirulina</Emphasis>) intracellular and extracellular metabolites using multifactor stress combination approach

The interactive effects of light intensity, NaCl, nitrogen, and phosphorus on intracellular biomass content and extracellular polymeric substance production were assessed for Arthrospira sp. (Spirulina) in a two-phase culture process using principal component analysis and central composite face design. Under high light intensity (120 μmol photons m^?2?s^?1) and low NaCl (1 gL^?1), NaNO₃, and K₂HPO₄ (0.5 g L^?1), the carbohydrate content was maximized to 26.61%. Interaction of both K₂HPO₄ (1.6 gL^?1) and NaCl (1.19 gL^?1) with low NaNO₃ (0.5 gL^?1) achieved the maximum content of lipids (15.62%), while high NaCl (40 gL^?1), K₂HPO₄, and NaNO₃ (4.5 gL^?1) enhanced mainly total carotenoids (0.85%). Conversely, under low light intensity of 10 μmol photons m^?2?s^?1 combined with 11.76 gL^?1 of NaCl, 0.5 gL^?1 of NaNO₃, and 2.68 gL^?1 of K₂HPO₄, the phycobiliprotein content reached its highest level (16.09%). The maximum extracellular polymeric substance (EPS) production (0.902 gg^?1?DW) was triggered under moderate light of 57.25 μmol photons m^?2?s^?1 and interaction of high NaCl (40 gL^?1) and K₂HPO₄ (4.5 gL^?1) with low NaNO₃ (0.5 gL^?1). The maximization ratios of intracellular biomass content in terms of carbohydrate, lipid, total carotenoid, phycobiliprotein, and EPS production were 3.55-, 1.73-, 9.55-, 2.92-, and 1.46-fold, respectively, greater than those obtained at optimal growth conditions. This study demonstrated that the multiple stress factors applied to the adopted two-phase culture process could be a promising strategy to produce biomass enriched in various high-value compound.     

Surface energy fluxes and control of evapotranspiration from a <Emphasis Type="Italic">Carex lasiocarpa</Emphasis> mire in the Sanjiang Plain,Northeast China

Data from four components of the radiation balance were used to investigate the surface energy budgets for a Carex lasiocarpa mire in the Sanjiang Plain, Northeast China, and the controlling factors of the evapotranspiration (ET) were discussed in detail. During the growing season 2006, the shortwave radiation (SW↓) reaching the mire surface added up to 2,854.3 MJ m⁻² and the net radiation (Rn) was 1,637.4 MJ m⁻² in total, with an average of 9.86 MJ m⁻² day⁻¹. G was the smallest flux at the water-atmosphere interface, with an average of about 0.91 MJ m⁻² day⁻¹, but showed high relative variability, even changing its sign. The latent and sensible heat fluxes (LE and H) amounted to 787.48 and 476.26 MJ m⁻², respectively, and the total sum of LE and H accounted for 77.18% of Rn. By conversion from LE, the average value of ET from the mire was 1.84 mm day⁻¹, amounting to 298.8 mm. The total ET was almost 60% of the total rainfall in the same period, proving that ET is the primary water consumer in the mire. The growth of C. lasiocarpa was related closely with surface resistance (r _s), and analysis of partial correlation indicated that r _s correlated negatively with leaf area index (LAI) when the interference of the available energy, Rn-G, was removed. There was a strong linkage between r _s and the evaporative fraction [LE/(LE + H)] as well as Bowen ratio (β). r _s was the key factor in controlling the variation of ET and regulating energy partitioning between LE and H. During the whole growing season, r _s and R _n−G were the two main factors coupled in ET processes. In spring, r _s dominated ET processes, and the increase in LAI led to a decrease in r _s, which in turn accelerated ET as vegetation developed until late August. After August, the available energy controlled the process of ET completely until ET reached an equilibrium in mid-October.     

High heterotrophic CO<Subscript>2</Subscript> emissions from a Malaysian oil palm plantations during dry-season

Tropical peatlands are currently being rapidly cleared and drained for the establishment of oil palm plantations, which threatens their globally significant carbon sequestration capacity. Large-scale land conversion of tropical peatlands is important in the context of greenhouse gas emission factors and sustainable land management. At present, quantification of carbon dioxide losses from tropical peatlands is limited by our understanding of the relative contribution of heterotrophic and autotrophic respiration to net peat surface CO₂ emissions. In this study we separated heterotrophic and autotrophic components of peat CO₂ losses from two oil palm plantations (one established in ‘2000’ and the other in 1978, then replanted in ‘2006’) using chamber-based emissions sampling along a transect from the rooting to non-rooting zones on a peatland in Selangor, Peninsular Malaysia over the course of 3 months (June–August, 2014). Collar CO₂ measurements were compared with soil temperature and moisture at site and also accompanied by depth profiles assessing peat C and bulk density. The soil respiration decreased exponentially with distance from the palm trunks with the sharpest decline found for the plantation with the younger palms with overall fluxes of 1341 and 988 mg CO₂ m^?2 h^?1, respectively, at the 2000 and 2006 plantations, respectively. The mean heterotrophic flux was 909 ± SE 136 and 716 ± SE 201 mg m^?2 h^?1 at the 2000 and 2006 plantations, respectively. Autotrophic emissions adjacent to the palm trunks were 845 ± SE 135 and 1558 ± SE 341 mg m^?2 h^?1 at the 2000 and 2006 plantations, respectively. Heterotrophic CO₂ flux was positively related to peat soil moisture, but not temperature. Total peat C stocks were 60 kg m^?2 (down to 1 m depth) and did not vary among plantations of different ages but SOC concentrations declined significantly with depth at both plantations but the decline was sharper in the second generation 2006 plantation. The CO₂ flux values reported in this study suggest a potential for very high carbon (C) loss from drained tropical peats during the dry season. This is particularly concerning given that more intense dry periods related to climate change are predicted for SE Asia. Taken together, this study highlights the need for careful management of tropical peatlands, and the vulnerability of their carbon storage capability under conditions of drainage.     

The growth of <Emphasis Type="Italic">Chlorella sorokiniana</Emphasis> as influenced by CO<Subscript>2</Subscript>, light,and flue gases

In order to achieve recognition as environmentally friendly production, flue gases should be used as a CO₂ source for growing the microalgae Chlorella sorokiniana when used for hydrogen production. Flue gases from a waste incinerator and from a silicomanganese smelter were used. Before testing the flue gases, the algae were grown in a laboratory at 0.04, 1.3, 5.9, and 11.0 % (v/v) pure CO₂ gas mixed with fresh air. After 5 days of growth, the dry biomass per liter algal culture reached its maximum at 6.1 % CO₂. A second experiment was conducted in the laboratory at 6.2 % CO₂ at photon flux densities (PFD) of 100, 230, and 320 μmol photons m^?2 s^?1. After 4 days of growth, increasing the PFD increased the biomass production by 67 and 108 % at the two highest PFD levels, as compared with the lowest PFD. A bioreactor system containing nine daylight-exposed tubes and nine artificial light-exposed tubes was installed on the roof of the waste incinerator. The effect of undiluted flue gas (10.7 % CO₂, 35.8 ppm NO _x , and 38.6 ppm SO₂), flue gas diluted with fresh air to give 4.2 % CO₂ concentration, and 5.0 % pure CO₂ gas was studied in daylight (21.4?±?9.6 mol photons m^?2 day^?1 PAR, day length 12.0 h) and at 135 μmol photons m^?2 s^?1 artificial light given 24 h day^?1 (11.7?±?0.0 mol photons m^?2 day^?1 PAR). After 4 days’ growth, the biomass production was the same in the two flue gas concentrations and the 5 % pure CO₂ gas control. The biomass production was also the same in daylight and artificial light, which meant that, in artificial light, the light use efficiency was about twice that of daylight. The starch concentration of the algae was unaffected by the light level and CO₂ concentration in the laboratory experiments (2.5–4.0 % of the dry weight). The flue gas concentration had no effect on starch concentration, while the starch concentration increased from about 1.5 % to about 6.0 % when the light source changed from artificial light to daylight. The flue gas from the silicomanganese smelter was characterized by a high CO₂ concentration (about 17 % v/v), low oxygen concentration (about 4 %), about 100 ppm NO _x , and 1 ppm SO₂. The biomass production using flue gas significantly increased as compared with about 5 % pure CO₂ gas, which was similar to the biomass produced at a CO₂ concentration of 10–20 % mixed with N₂. Thus, the enhanced biomass production seemed to be related to the low oxygen concentration rather than to the very high CO₂ concentration.     

Photosynthetic capacity of the capsule wall and its contribution to carbon fixation and seed yield in castor (<Emphasis Type="Italic">Ricinus communis</Emphasis> L.)

Defoliation occurs in castor due to several reasons, but the crop has propensity to compensate for the seed yield. Photosynthetic efficiency in terms of functional (gas exchange and chlorophyll fluorescence) and structural characteristics (photosynthetic pigment profiles and anatomical properties) of castor capsule walls under light- and dark-adapted conditions was compared with that of leaves. Capsule wall showed high intrinsic efficiency of photosystem II (F _v/F _m, 0.82) which was comparable to leaves (F _v/F _m, 0.80). With increasing photon flux densities (PFD), actual quantum yields and photochemical quenching coefficients of the capsule walls were similar to that in leaves, while electron transport rates reached a maximum corresponding to about 118 % of the leaves. However, maximum net photosynthetic rate of the capsule walls (2.60 µmol CO₂ m^?2 s^?1) was less than one-fourth of the leaves (15.67 µmol CO₂ m^?2 s^?1) at the CO₂ concentration of 400 µmol mol^?1, and the difference was attributed to about 80 % lower stomatal density and the 75 % lower total chlorophyll content of capsule walls than the leaves. Furthermore, seed weight in dark-adapted capsules was 2.70–12.42 % less as compared to the capsules developed under light. The results indicate that castor capsule walls are photosynthetically active (about 15–30 % of the leaves) and contribute significantly to carbon fixation and seed yield accounting for 10 % photoassimilates towards seed weight.     

Spectroscopic studies on the interaction mechanisms of safranin T with herring sperm DNA using acridine orange as a fluorescence probe

Under the condition of physiological pH environment (pH = 7.40), the interactions of safranin T (ST) with herring sperm DNA were studied by means of spectral methods using acridine orange (AO) as a fluorescence probe. The spectroscopic characteristics of DNA–AO in the case of ST (along with the increase of concentration) were observed in an aqueous medium. The binding constants for ST stranded DNA and competitive bindings of ST interacting with DNA–AO systems were examined by fluorescence spectra, and the binding mechanism of ST with DNA was researched via viscosity measurements. All the testimony manifested that bonding modes between ST and DNA were evidenced to be intercalative binding and electrostatic binding, and the combining constant of ST with DNA was obtained. The binding of ST to DNA was driven by entropy and enthalpy through the calculated thermodynamic parameters (Δ_rH_m^?, Δ_rS_m and Δ_rG_m^?). Copyright © 2014 John Wiley & Sons, Ltd.     

Flow Cytometry Analysis of Neural Differentiation Markers Expression in Human Glioblastomas May Predict Their Response to Chemotherapy

Glioblastoma multiforme (GBM) represents an extremely chemoresistant tumour type. Here, authors analysed the immunophenotype of GBM tumours by flow cytometry and correlated the immunophenotypic characteristics with sensitivity to chemotherapy. The expression of selected neural and non-neural differentiation markers including A2B5, CD34, CD45, CD56, CD117, CD133, EGFR, GFAP, Her-2/neu, LIFR, nestin, NGFR, Pgp and vimentin was analysed by flow cytometry in eleven GBM (WHO gr.IV) patients. The sensitivity of tumour cells to a panel of chemotherapeutic agents was tested by the MTT assay. All tumours were positive for A2B5, CD56, nestin and vimentin. CD133, EGFR, LIFR, NGFR and Pgp were expressed only by minor tumour cell subpopulations. CD34, CD45, CD117, GFAP and Her-2/neu were constantly negative. Direct correlations were found between the immunophenotypic markers and chemosensitivity: A2B5 vs lomustine (r² = 0.642, P = 0.033), CD56 vs cisplatin (r² = 0.745, P = 0.013), %Pgp⁺ vs vincristine (r² = 0.846, P = 0.008), and %NGFR⁺ vs daunorubicine (r² = 0.672, P = 0.047) and topotecan (r² = 0.792, P = 0.011). In contrast, inverse correlations were observed between: EGFR vs paclitaxel (r² = ?0.676, P = 0.046), CD133 vs dacarbazine (r² = ?0.636, P = 0.048) and LIFR vs daunorubicine (r² = ?0.878, P = 0.004). Finally, significant associations were also found among sensitivities to different chemotherapeutic agents and among different immunophenotypic markers. In conclusion, histopathologically identical GBM tumours displayed a marked immunophenotypic heterogeneity. The expression of A2B5, CD56, NGFR and Pgp appeared to be associated with chemoresistance whereas CD133, EGFR and LIFR expression was characteristic of chemosensitive tumours. We suggest that flow cytometric imunophenotypic analysis of GBM may predict chemoresponsiveness and help to identify patients who could potentially benefit from chemotherapy.     

Enhancing soil health and productivity of Lycopersicon esculentum Mill. using Sargassum johnstonii Setchell & Gardner as a soil conditioner and fertilizer

This study was aimed at developing a protocol for improving soil health using Sargassum johnstonii as a conditioner and fertilizer. Tomato (Lycopersicon esculentum) plants were raised on seaweed-amended soil in experimental fields of Department of Botany, University of Delhi, India. Soil was amended with granular (G) and powder (P) seaweed forms in the proportion of 12.5 % (G₁ and P₁), 25 % (G₂ and P₂), and 37.5 % (G₃ and P₃) (w/w). To compare the efficacy of seaweed fertilizer with a conventional organic fertilizer, a parallel series (positive control) was run with vermicompost (V) in the above-mentioned proportions. Unamended soil served as control (C). The nutrient status of S. johnstonii and vermicompost was analyzed prior to giving treatments. Physicochemical properties of the amended soils as well as growth, productivity, and biochemical constituents of tomato grown in soil with each treatment were analyzed. Higher concentration of granular form of seaweed (G₃) in the soil resulted in 144, 268, 122, 138, and 188 % increase in Na, K, Mg, Ca, and Zn, respectively. Seaweed-amended soil had higher porosity and water-holding capacity as compared to C. Tomato plants raised on seaweed (G₃ and P₃)-amended soil showed an increased overall growth, with earlier flowering and fruiting as compared to control plants. Plants raised on G₃-amended soil showed significantly higher levels of proteins (95 mg?g^?1 FW) in leaves, and vitamin C (99.2 mg 100 g^?1) and lycopene (5.78 mg 100 g^?1) in fruits. The present study showed that S. johnstonii biomass has a high potential to condition and fertilize the soil for improved crop productivity.