Short-distance pollen dispersal and high self-pollination in a bat-pollinated neotropical tree

We investigated pollen dispersal and breeding structure in the tropical tree species Caryocar brasiliense Camb. (Caryocaraceae), using genetic data from ten microsatellite loci. All adult trees (101) within a patch of 8.3 ha were sampled, and from these adults 18 open-pollinated maternal progeny arrays were analyzed (280 seeds from 265 fruits). Most fruits presented only one seed (median equal to 1.000) and mean number of ripened seeds per fruit was 1.053 (SD?=?0.828). Our results showed that C. brasiliense presents a mixed-mating system, with 11.4% of self-pollination, multilocus outcrossing rate of t _m?=?0.891?±?0.025, and high probability of full-sibship within progeny arrays (r _p?=?0.135?±?0.032). Outcrossing rate and self-pollination varied significantly among mother trees. We could detect a maximum pollen dispersal distance of ～500 m and a mean pollen dispersal distance of ～132 m. However, most pollination events (80%) occurred at distances less than 200 m. Our results also indicated that pollen dispersal is restricted to a neighborhood of 5.4 ha with rare events of immigration (～1% N _e m?=?0.35). C. brasiliense also presents a significant but weak spatial genetic structure (Sp?=?0.0116), and extension of pollen dispersal distance was greater than seed dispersal (N _b?=?86.20 m). These results are most likely due to the foraging behavior of pollinators that may have limited flight range. The highly within-population synchronous flowering, high population density, and clumped distribution reinforce pollinator behavior and affect residence time leading to a short-distance pollen dispersal.     

Extensive pollen flow in a natural fragmented population of Patagonian cypress Austrocedrus chilensis

Habitat fragmentation might significantly affect mating and pollen dispersal patterns in plant populations, contributing to the decline of remnant populations. However, wind-pollinated species are able to disperse pollen at longer distances after opening of the canopy. Our objectives were to characterize the mating system parameters and to estimate the average distance of effective pollen dispersal in the wind-pollinated conifer Austrocedrus chilensis. We sampled 19 “mother trees,” 200 progeny, and 81 additional adults (both male and female), in a fragmented population at the Argentinean Patagonian steppe. We registered the spatial positions of individuals and genotyped all samples with five microsatellite markers. We found a high genetic diversity, a moderated rate of biparental inbreeding (t _m? ??t _s?=?0.105), and a complete absence of correlated paternity (r _p?=??0.015). The effective number of pollen donors contributing to a single mother (N _ep) was 13.9. Applying TWOGENER, we estimated a low but significant differentiation among the inferred pollen pools (Φ_FT?=?0.036, p?=?0.001) and a very large average pollen dispersal distance (d?=?1,032.3 m). The leptokurtic distribution (b?=?0.18) presumes a potential for even larger dispersal distances. The high genetic diversity, the mating patterns, and the extensive pollen dispersal presume that habitat fragmentation did not have a negative impact on pollen movement in this population of A. chilensis. Genetic connectivity among fragmented populations scattered in the Patagonian region is possible, and we stress the need of management policies at the landscape level.     

Associations between interleukin-23 receptor polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis

The aim of this study was to determine whether interleukin-23 receptor (IL-23R) polymorphisms confer susceptibility to rheumatoid arthritis (RA). A meta-analysis was conducted on the associations between the IL-23R rs1343151, rs10489629, rs7517847, rs11209026, rs1004819, and rs2201841 polymorphisms and RA using (1) allele contrast, (2) the recessive model, (3) the dominant model, and (4) the additive model. A total of 13 studies from eight articles involving 10,016 RA patients and 11,967 controls were considered in the meta-analysis. Meta-analysis identified a significant association between RA and the A allele of the rs1343151 polymorphism in the overall population (OR?=?1.110, 95?% CI?=?1.056–1.168, p?=?4.7?×?10^?6). Stratification by ethnicity identified a significant association between this polymorphism and RA in Europeans (OR?=?1.105, 95?% CI?=?1.049–1.163, p?=?1.4?×?10^?5). An association was also found between RA and the A allele carrier of the rs1343151 polymorphism in Europeans (OR?=?1.135, 95?% CI?=?1.058–1.217, p?=?4.0?×?10^?5). Meta-analysis revealed a significant association between RA and the A allele of the rs10489629 polymorphism in the overall population (OR?=?1.079, 95?% CI?=?1.029–1.131, p?=?0.002) and in Europeans (OR?=?1.092, 95?% CI?=?1.038–1.149, p?=?0.001). Meta-analyses of recessive, dominant, and additive models showed the same pattern as the meta-analysis of the A allele of the rs10489629 polymorphism, that is, a significant association with RA in Europeans. However, no association was found between the IL-23R rs7517847, rs11209026, rs1004819, and rs2201841 polymorphisms and RA susceptibility. This meta-analysis shows that the IL-23R rs1343151 and rs10489629 polymorphisms are associated with the development of RA in Europeans. These findings suggest that the IL-23R genes confer susceptibility to RA in the European population, but further study of this association is required in other ethnic groups.     

Short-distance pollen dispersal for an outcrossed, wind-pollinated southern beech (Nothofagus nervosa (Phil.) Dim. et Mil.)

The mating system (outcrossing, selfing, and biparental inbreeding) and the extent of pollen flow are two of the most important genetic features that determine the genetic structure of plant populations, and both are crucial for the design of conservation strategies. The objectives here were to estimate mating system parameters and to fit the pollen dispersal kernel for the southern beech, Nothofagus nervosa. We sampled 25 mothers and 372 progeny from two stands in the Tromen Lake region of Argentina. We registered spatial positions of the maternal trees, and genotyped mothers and offspring for five simple sequence repeat markers. We estimated single-locus (t _s?=?0.95) and multilocus (t _m?=?0.99) outcrossing rates and biparental inbreeding (t _m-t _s?=?0.04). The species is strongly outcrossing, but correlated paternity within maternal sibships (r _p?=?0.10) indicates that each maternal parent is sampling a different and restricted array of pollen donors. We used two protocols (twogener and kindist) to fit an exponential power dispersal kernel to the structure of pollen clouds sampled by different mothers. The estimated effective number of pollen donors contributing to a single mother was N _ep?=?9.9. The twogener and kindist analyses yielded slightly different estimates, but both indicated short average distances for pollen dispersal (<35?m), indicating that the dispersal kernel was strongly leptokurtic (???=?0.36). While short-distance pollen dispersal predominates, there remains a nontrivial probability of long-distance dispersal. The results are discussed in the context of ongoing conservation and management programs.     

Synthesis and activity of di- or trisubstituted N-(phenoxyalkyl)- or N-{2-[2-(phenoxy)ethoxy]ethyl}piperazine derivatives on the central nervous system

Aim of the study was evaluation of anxiolytic, antidepressant, anticonvulsant and analgesic activity in a series of a consistent group of compounds. A series of eleven new N-(phenoxyalkyl)- or N-{2-[2-(phenoxy)ethoxy]ethyl}piperazine derivatives has been obtained. Their affinity towards 5-HT_1A, 5-HT_2A, 5-HT₆, 5-HT₇, D₂ and α₁ receptors has been assessed, and then functional assays were performed. The compounds were evaluated in mice, i.p. for their antidepressant-like (forced swim test), locomotor, anxiolytic-like (four-plate test) activities as well as – at higher doses – for anticonvulsant potential (MES) and neurotoxicity (rotarod). Two compounds (3, 6) were also evaluated for their analgesic activity in neuropathic pain models (streptozocin test, oxaliplatin test) and they were found active against allodynia in diabetic neuropathic pain at 30?mg/kg. Among the compounds, anxiolytic-like, anticonvulsant or analgesic activity was observed but antidepressant-like activity was not. One of the two most interesting compounds is 1-{2-[2-(2,4,6-trimethylphenoxy)ethoxy]ethyl}-4-(2-methoxyphenyl)piperazine dihydrochloride (9), exhibiting anxiolytic and anticonvulsant activity in mice, i.p. 30 min after administration (at 2.5?mg/kg and ED₅₀?=?26.33?mg/kg, respectively), which can be justified by the receptor profile: 5-HT_1A K_i?=?5?nM (antagonist), 5-HT₇ K_i?=?70?nM, α₁ K_i?=?15?nM, D₂ K_i?=?189?nM (antagonist). Another interesting compound is 1-[3-(2,4,6-trimethylphenoxy)propyl]-4-(4-methoxyphenyl)piperazine dihydrochloride (3), exhibiting anxiolytic, anticonvulsant and antiallodynic activity in mice, i.p., 30?min after administration (at 10?mg/kg, ED₅₀?=?23.50?mg/kg, at 30?mg/kg, respectively), which can be related with 5-HT_1A weak antagonism (K_i?=?146?nM), or other possible mechanism of action, not evaluated within presented study. Additionally, for the most active compound in the four-plate test (7), molecular modeling was performed (docking to receptors 5-HT_1A, 5-HT_2A, 5-HT₇, D₂ and α_1A).     

Characterization of protein expression of Platanus pollen following exposure to gaseous pollutants and vehicle exhaust particles

Being major ornamental street trees, species of Platanus are widely planted in the Shanghai urban area. A great deal of allergenic Platanus pollen is released from the trees and suspended in the atmosphere during its flowering season, ultimately causing allergic respiratory diseases. Few papers have focused on the distribution of this type of pollen and its expression of allergenic proteins. In order to investigate any differences in protein expression in Platanus pollen following exposure to gaseous and particulate pollutants, a special apparatus was designed. Exposure condition (such as temperature, humidity, and exposure time) of Platanus pollen and gaseous pollutants can be simulated using of this apparatus. Fresh Platanus orientalis pollen, pollutant gases (NO₂, SO₂, NH₃), and typical urban ambient particles (vehicle exhaust particles, VEPs) were mixed in this device to examine possible changes that might occur in ambient airborne urban pollen following exposure to such pollutants. Our results showed that the fresh P. orientalis pollen became swollen, and new kinds of particles could be found on the surface of the pollen grains after exposure to the pollutants. The results of SDS-PAGE showed that five protein bands with molecular weights of 17–19, 34, 61, 82, and 144 kDa, respectively, were detected and gray scale of these brands increased after the pollen exposure to gaseous pollutants. The two-dimensional gel electrophoresis analysis demonstrated that a Platanus pollen allergenic protein (Pla a1, with a molecular weight of 18 kDa) increased in abundance following exposure to pollutant gases and VEPs, implying that air pollutants may exacerbate the allergenicity of pollen.     

Plasma levels of alarmin HNPs 1–3 associate with lung dysfunction after cardiac surgery in children

Background

Early onset of lung injury is considerable common after cardiac surgery and is associated with increasing in morbidity and mortality, but current clinical predictors for the occurrence of this complication always have limited positive warning value. This study aimed to evaluate whether elevated plasma levels of human neutrophil peptides (HNPs) 1–3 herald impaired lung function in infants and young children after cardiac surgery necessitating cardiopulmonary bypass (CPB).

Methods

Consecutive children younger than 3 years old who underwent cardiac surgery were prospectively enrolled. Plasma concentrations of HNPs 1–3 and inflammatory cytokines were measured before, and immediately after CPB, as well as at 1 h, 12 h, and 24 h after CPB.

Results

Thirty patients were enrolled, 18 (60%) of whom were infants. Plasma levels of HNPs 1–3 and the pro-inflammatory cytokine interleukin-6 (IL-6) significantly increased immediately after CPB (P?<?0.001), while IL-8 increased 1 h after the CPB operation (P?=?0.002). The anti-inflammatory cytokine IL-10 levels were also significantly elevated immediately after CPB compared with the baseline (P?<?0.001). The stepwise multiple linear regression analysis showed that the plasma HNPs 1–3 levels immediately after CPB was independent correlated with the declined lung function, as reflected by the PaO₂/FiO₂ ratio on the first 2 days after operation (for the first day: OR, ?1.067, 95% CI, ?0.548 to ?1.574; P?<?0.001; for the second day: OR, ?0.667, 95% CI, ?0.183 to ?1.148; P?=?0.009) and prolonged mechanical ventilation time (OR, 0.039, 95% CI, 0.005 to 0.056; P?=?0.011). Plasma levels of HNPs 1–3 and IL-10 returned to the baseline values, while IL-6 and IL-8 levels remained significantly higher than baseline 24 h after CPB (P?≤?0.01).

Conclusions

Elevated HNPs 1–3 levels immediately after CPB correlate with impaired lung function, and HNPs 1–3 could serve as a quantifiable early alarmin biomarker for onset of lung injury in infants and young children undergoing cardiac surgery with CPB.

     

Spatial Scales of Pollen and Seed-Mediated Gene Flow in Tropical Rain Forest Trees

Gene flow via seed and pollen is a primary determinant of genetic and species diversity in plant communities at different spatial scales. This paper reviews studies of gene flow and population genetic structure in tropical rain forest trees and places them in ecological and biogeographic context. Although much pollination is among nearest neighbors, an increasing number of genetic studies report pollination ranging from 0.5–14 km for canopy tree species, resulting in extensive breeding areas in disturbed and undisturbed rain forest. Direct genetic measures of seed dispersal are still rare; however, studies of fine scale spatial genetic structure (SGS) indicate that the bulk of effective seed dispersal occurs at local scales, and we found no difference in SGS (Sp statistic) between temperate (N?=?24 species) and tropical forest trees (N?=?15). Our analysis did find significantly higher genetic differentiation in tropical trees (F _ST?=?0.177; N?=?42) than in temperate forest trees (F _ST?=?0.116; N?=?82). This may be due to the fact that tropical trees experience low but significant rates of self-fertilization and bi-parental inbreeding, whereas half of the temperate tree species in our survey are wind pollinated and are more strictly allogamous. Genetic drift may also be more pronounced in tropical trees due to the low population densities of most species.     

Differences in Zn and Pb resistance of two ecotypes of the microalga Eustigmatos sp. inhabiting metal loaded calamine mine spoils

Soil-dwelling microalgae as pioneer organisms may play an essential role in degraded post-industrial areas. Zn and Pb resistance of two morphologically identical strains (E120, E5) of the soil microalga Eustigmatos sp. (Eustigmatophyceae) inhabiting two extremely metal polluted calamine mine spoils and Eustigmatos vischeri (Ev) from algal collection was compared. To compare Zn and Pb resistance of algal strains, toxicity parameters (72/96 h-EC₅₀) were determined during their exposure to high Zn (50–800 μM) and Pb (5–80 μM) concentrations. Both Zn- and Pb-EC₅₀ values increased as follows: Ev < E5 < E120. The E120 strain from the mine spoil with the highest metal contents appeared to be two times more Zn and Pb resistant (96 h-EC₅₀?=?416 μM Zn, 39.8 μM Pb) than E5 strain from the less metal polluted site and 4.7–8.8 times more than Ev. Differences in Zn and Pb accumulation as well as in metal-induced membrane lipid peroxidation were also observed. The present study highlights the evolution of algal ecotypes of high but various Zn and Pb resistance as a result of natural exposure to different metal concentrations in their habitats. The algae of high heavy metal resistance could have a practical application in remediation of contaminated soils of anthropogenic origin.     

The effects of lead on photosynthetic performance of waxberry seedlings (<Emphasis Type="Italic">Myrica rubra</Emphasis>)

The photosynthesis was investigated 30 d after Pb treatment in Myrica rubra seedlings. The Pb treatment resulted in significantly increased Pb concentrations in shoots. Low Pb concentration exposure (≤2 mM) reduced the net photosynthetic rate (P_N), transpiration rate (E), and stomatal conductance (gs) without affecting the intercellular CO₂ concentration (C_i), chlorophyll (Chl) content, and Chl fluorescence parameters. At 10 d after severe Pb treatment (≥4 mM), P_N was inhibited and accompanied by Chl damage, while at 30 d, the inhibition of P_N was followed by an increase of C_i and a decrease of gs, E, Chl content, and Chl fluorescence parameters. M. rubra showed a promising prospect for use in the soil phytoremediation, when Pb concentration is low, but the remediation efficiency of M. rubra is limited if Pb exceeds 2 mM.     

Prostate Tissue Metal Levels and Prostate Cancer Recurrence in Smokers

Although smoking is not associated with prostate cancer risk overall, smoking is associated with prostate cancer recurrence and mortality. Increased cadmium (Cd) exposure from smoking may play a role in progression of the disease. In this study, inductively coupled plasma mass spectrometry was used to determine Cd, arsenic (As), lead (Pb), and zinc (Zn) levels in formalin-fixed paraffin embedded tumor and tumor-adjacent non-neoplastic tissue of never- and ever-smokers with prostate cancer. In smokers, metal levels were also evaluated with regard to biochemical and distant recurrence of disease. Smokers (N?=?25) had significantly higher Cd (median ppb, p?=?0.03) and lower Zn (p?=?0.002) in non-neoplastic tissue than never-smokers (N?=?21). Metal levels were not significantly different in tumor tissue of smokers and non-smokers. Among smokers, Cd level did not differ by recurrence status. However, the ratio of Cd ppb to Pb ppb was significantly higher in both tumor and adjacent tissue of cases with distant recurrence when compared with cases without distant recurrence (tumor tissue Cd/Pb, 6.36 vs. 1.19, p?=?0.009, adjacent non-neoplastic tissue Cd/Pb, 6.36 vs. 1.02, p?=?0.038). Tissue Zn levels were also higher in smokers with distant recurrence (tumor, p?=?0.039 and adjacent non-neoplastic, p?=?0.028). These initial findings suggest that prostate tissue metal levels may differ in smokers with and without recurrence. If these findings are confirmed in larger studies, additional work will be needed to determine whether variations in metal levels are drivers of disease progression or are simply passengers of the disease process.     

Evaluation of meiotic abnormalities and pollen viability in aposporous and sexual tetraploid Paspalum notatum (Poaceae)

We analyzed anaphase I configurations and pollen viability in aposporous and sexual tetraploid (2n?=?4x?=?40) cytotypes of Paspalum notatum. Five natural aposporous accessions and three experimentally obtained sexual individuals were used. In addition, 16 (8 aposporous and 8 sexual) F₁ hybrids, previously classified by their mode of reproduction, were analyzed. Cytogenetic observations revealed normal and abnormal anaphase I configurations in both aposporous and sexual genotypes. Anaphase I abnormalities were mainly laggard chromosomes, chromatin bridges, and micronuclei. On average, 44.36?% of aposporous meiocytes and 29.66?% of sexual ones showed abnormal anaphase I configurations. The total numbers of normal and abnormal anaphase I were highly significantly different between aposporous and sexual strains. The pollen viability test indicated that aposporous individuals had significantly more non-viable pollen than sexual ones; a positive correlation (r?=?0.71; r ²?=?0.50) between the variables was detected. Analysis of aposporous and sexual hybrids confirmed differences in the numbers of normal and abnormal anaphase I patterns in the aposporous and sexual parents. However, similar proportions of viable pollen were produced by both groups of hybrids. In this case, the variables were not correlated (r?=?0.23; r ²?=?0.05). Data from this study indicated that aposporous strains had a genetic rearrangement affecting meiosis that was absent in the experimentally obtained sexual individuals and that it was transmitted to the progeny. The possible association between meiotic abnormalities and the inheritance of apospory is discussed.     

Design,synthesis and evaluation of N2,N4-diaminoquinazoline based inhibitors of phosphodiesterase type 5

We describe the design, synthesis and evaluation of a series of N²,N⁴-diaminoquinazoline analogs as PDE5 inhibitors. Twenty compounds were prepared and these were assessed in terms of their PDE5 and PDE6 activity, ex-vivo vasodilation response, mammalian cytotoxicity and aqueous solubility. Molecular docking was used to determine the binding mode of the series and this was demonstrated to be consistent with the observed SAR. Compound 15 was the most active PDE5 inhibitor (IC₅₀?=?0.072?±?0.008?µM) and exhibited 4.6-fold selectivity over PDE6. Ex-vivo assessment of 15 and 22 in a rat pulmonary artery vasodilation model demonstrated EC₅₀s of 1.63?±?0.72?µM and 2.28?±?0.74?µM respectively.     

Progress in Dodecafluoropentane Emulsion as a Neuroprotective Agent in a Rabbit Stroke Model

Dodecafluoropentane emulsion (DDFPe) in 250 nm nanodroplets seems to swell modestly to accept and carry large amounts of oxygen in the body at >29 °C. Small particle size allows oxygen delivery even into hypoxic tissue unreachable by erythrocytes. Using permanent cerebral embolic occlusion in rabbits, we assessed DDFPe dose response as a neuroprotectant at 7 and 24 h post-embolization without lysis of arterial obstructions and investigated blood pharmacokinetics. New Zealand White rabbits (N?=?56) received cerebral angiography and embolic spheres (diameter?=?700–900 μm) occluded middle and/or anterior cerebral arteries. Intravenous DDFPe dosing (2 %?w/v emulsion) began at 60 min and repeated every 90 min until sacrifice at 7 or 24 h post-embolization. Seven-hour groups: (1) control (embolized without treatment, N?=?6), and DDFPe treatment: (2) 0.1 ml/kg (N?=?7), (3) 0.3 ml/kg (N?=?9), (4) 0.6 ml/kg (N?=?8). Twenty-four-hour groups: (5) control (N?=?16), and DDFPe treatment: (6) 0.1 ml/kg (N?=?10). Infarcts as percent of total brain volume were determined using vital stains on brain sections. Other alert normal rabbits (N?=?8) received IV doses followed by rapid arterial blood sampling and GC-MS analysis. Percent infarct volume means significantly decreased for all DDFPe-treated groups compared with controls, p?=?<0.004 to <0.03. Blood DDFP (gas) half-life was 1.45?±?0.17 min with R?=?0.958. Mean blood clearance was 78.5?±?24.9 ml/min/kg (mean?±?SE). Intravenous DDFPe decreases ischemic stroke infarct volumes. Blood half-life values are very short. The much longer therapeutic effect, >90 min, suggests multiple compartments. Lowest effective dose and maximum effective therapy duration are not yet defined. Rapid development is warranted.     

Combined Impact of Exercise and Temperature in Learning and Memory Performance of Fluoride Toxicated Rats

In previous studies, we investigated a link between high fluoride exposure and functional IQ deficits in rats. This study is an extension conducted to explore the combined influence of physical exercise and temperature stress on the learning ability and memory in rats and to assess whether any positive modulation could be attenuated due to exercise regimen subjected to F-toxicated animals at different temperatures. Accumulation of ingested fluoride resulted significant inhibition in acetylcholinesterase activity (P?<?0.05), plasma cortisol levels (P?<?0.05), and impaired the acquisition, performance, latency time, and retention in fluoride-exposed animals. Fluoride-toxicated rats took more number of sessions during the learning phase [F _{5, 35}?=?19.065; P?<?0.05] and post hoc analysis on the number of correct choices revealed that there was a significant effect of treatments [F _{5, 30}?=?15.763; P?<?0.05]; sessions [F _{8, 240}?=?58.698; P?<?0.05]; and also significant difference in the interactions [F _{40, 240}?=?1.583; P?<?0.05]. The latency data also revealed a significant difference between groups [F _{5, 30}?=?28.085; P?<?0.05]; time?=?[F _{8, 240}?=?136.314; P?<?0.05]; and there was a significant difference in the interactions [F _{40, 240}?=?2.090; P?<?0.05]. In order to ascertain if interdependence between fluoride concentrations and the foregoing free radical parameters, respective correlation coefficients were calculated and results clearly emphasize the positive role of exercise in the promotion of cognitive functions by decreasing fluoride levels in rat hippocampus. A significant recovery in cognitive function was noticed in all the exercised animals due to reduced burden of brain oxidative stress. In comparison to exercise regimens performed at different temperatures, high (35?°C) and low temperatures (20?°C) led to a slower acquisition and poor retention of the task when compared to thermo neutral temperatures (25 and 30?°C). Thus exercise up-regulate antioxidant defenses and promote learning abilities in fluorotic population.     

Design,synthesis and algicides activities of thiourea derivatives as the novel scaffold aldolase inhibitors

By using a new Fragment-Based Virtual Screen strategy, two series of novel FBA-II inhibitors (thiourea derivatives) were de novo discovered based on the active site of fructose-1, 6-bisphosphate aldolase from Cyanobacterial (CyFBA). In comparison, most of the N-(2-benzoylhydrazine-1-carbonothioyl) benzamide derivatives (L14～L22) exhibit higher CyFBA-II inhibitory activities compared to N-(phenylcarbamothioyl) benzamide derivatives (L1～L13). Especially, compound L14 not only shows higher CyFBA-II activity (K_i?=?0.65?μM), but also exhibits most potent in vivo activity against Synechocystis sp. PCC 6803 (EC₅₀?=?0.09?ppm), higher (7-fold) than that of our previous inhibitor (EC₅₀?=?0.6?ppm). The binding modes of compound L14 and CyFBA-II were further elucidated by jointly using DOX computational protocol, MM-PBSA and site-directed mutagenesis assays. The positive results suggest that strategy adopted in this study was promising to rapidly discovery the potent inhibitors with novel scaffolds. The satisfactory algicide activities suggest that the thiourea derivatives is very likely to be a promising lead for the development of novel specific algicides to solve Cyanobacterial harmful algal blooms (CHABs).     

Influence of temperature on the in vitro pollen germination and pollen tube growth of various native Iranian almonds (Prunus L. spp.) species

Pollen germination and pollen tube growth was quantified among various native Iranian wild almonds (P. dulcis (Mill.) D. A. Webb, P. eleaegnifolia Mill., P. orientalis Mill., P. lycioides Spach, P. reuteri Bioss. et Bushe, P. arabica Olivier, P. glauca Browick and P. scoparia Spach in order to identify differences in the tolerance of pollen to temperature variations. Pollen germination and pollen tube growth were observed after incubation in darkness in a germination medium for 24?h at 10?C50°C at 5°C intervals. Maximum pollen germination of the wild almond species and specify that 60% was obtained for P. orientalis pollen and 98% for P. scoparia. Pollen tube length ranged from 860???m was obtained in P. lycioides and 1490???m in P. scoparia. A modified bilinear model best described the response to temperature of pollen germination and pollen tube length. Almond species variation was found for cardinal temperatures (T _min, T _opt and T _max) of pollen germination percentage and pollen tube growth. Mean cardinal temperatures averaged over eight almond species were 14.7, 24.2, and 43.7°C for maximum percentage pollen germination and 14.48, 25.3, and 44.4 °C for maximum pollen tube length. The principal component analysis (PCA) identified maximum percentage pollen germination and pollen tube length of the species, and T _max for the two processes as the most important pollen parameters in describing a species tolerance to high temperature. PCA also classified Prunus L. spp. into four groups according to the tolerance of pollen to temperature variations. The T _min and T _opt for pollen germination and tube growth, rate of pollen tube growth were less predictive in discriminating species for high temperature tolerance.     

Fed-Batch Cultivation of Arthrospira platensis Using Carbon Dioxide from Alcoholic Fermentation and Urea as Carbon and Nitrogen Sources

To reduce CO₂ emissions from alcoholic fermentation, Arthrospira platensis was cultivated in tubular photobioreactor using either urea or nitrate as nitrogen sources at different light intensities (60 μmol m^?2 s^?1?≤?I?≤?240 μmol m^?2 s^?1). The type of carbon source (pure CO₂ or CO₂ from fermentation) did not show any appreciable influence on the main cultivation parameters, whereas substitution of nitrate for urea increased the nitrogen-to-cell conversion factor (Y _X/N ), and the maximum cell concentration (X _m ) and productivity (P _X ) increased with I. As a result, the best performance using gaseous emissions from alcoholic fermentation (X _m ?=?2,960?±?35 g m^?3, P _X ?=?425?±?5.9 g m^?3 day^?1 and Y _X/N ?=?15?±?0.2 g g^?1) was obtained at I?=?120 μmol m^?2 s^?1 using urea as nitrogen source. The results obtained in this work demonstrate that the combined use of effluents rich in urea and carbon dioxide could be exploited in large-scale cyanobacteria cultivations to reduce not only the production costs of these photosynthetic microorganisms but also the environmental impact associated to the release of greenhouse emissions.     

Biogeochemistry of trimethyllead and lead in a forested ecosystem in Germany

Lead compounds, especially ionic organolead compounds (OLC), are highly toxic and mobile pollutants strongly affecting many ecosystems. Soil pools and fluxes with precipitation, litterfall and runoff of trimethyllead (TML), one of the dominant ionic OLC in the environment, and Pb_total were investigated in a forested ecosystem in NE-Bavaria, Germany. In addition, ad/desorption of TML to soils was studied in batch experiments and its degradation in soils was investigated using long term incubations. Total soil storage in the catchment was 11.56?mg Pb?ha^?1 for TML and 222?kg Pb?ha^?1 for Pb_total. More than 90% of the soil storage of TML was found in the wetland soils of the catchment representing only 30% of the area. Most Pb_total (>90%) was found in the upland soils. In upland soils, TML was only detectable in the forest floor. The annual total deposition from the atmosphere, estimated as throughfall?+?litterfall fluxes, amounted to 3.7?mg Pb?ha^?1 year^?1 for TML and 52?g Pb?ha^?1 year^?1 for Pb_total. The contribution of litterfall was 1.5 and 32%, respectively. The concentrations of TML and Pb_total in wet precipitation were: fog?>?throughfall?>?bulk precipitation. The annual fluxes with runoff from the catchment was 0.5?mg Pb?ha^?1 year^?1 for TML and 2.8?g Pb?ha^?1 year^?1 for Pb_total. TML degraded rapidly in the forest floor (Oa horizon) with a half-life (t) of 33.5 days. The degradation of TML in Fen (t?=?421 days) and in the mineral soil (Bw-C horizon, t?=?612 days) was much slower. Emission of tetramethyllead from wetland soils was not observed during the 1 year incubation. The adsorption affinity of TML to different soils was Fen?>?Oa?>?A?≥?Bw-C. The ratio of total soil storages to the present annual input were 3.6 years for TML. TML and Pb_total are still deposited in remote areas even after the use of tetraalkyllead as additives has been terminated for years. The rates of deposition are, however, much lower than in the past. Forest soils act as a sink for deposited TML and Pb_total. TML is accumulated mostly in wetland soils and seems to be stable under anoxic conditions for a long time. In upland soils, TML decomposes rapidly. Only small amounts of TML are transferred from soils into runoff.