The Use of Mixtures of Sulfur and Bracken Litter to Reduce pH of Former Arable Soils and Control Ruderal Species

High soil pH has been highlighted as a constraint to the restoration of heathland on ex‐arable land. Previous studies at the Minsmere Reserve of the Royal Society for the Protection of Birds (RSPB) in England have shown that it is possible to acidify ex‐arable soils using elemental sulfur and bracken litter, although sulfur (S) is more effective. Current recommendations suggest that 4 tS/ha need to be applied to reduce soil pH below pH 4, control vigorous ruderal species, and create conditions suitable for Calluna vulgaris (heather) establishment. However, S is relatively expensive, and as bracken litter is moderately abundant within the reserve, it made economic sense to evaluate the potential for mixing S with bracken to see if adequate pH reductions could be achieved at lower S rates. Accordingly an experiment was designed to test the effects of combining S (0–8 t S/ha) and bracken litter (0–10 cm depth layers) on (1) soil pH, (2) cover of ruderal species, and (3) the developing plant community. Significant interactions were detected, especially in the period immediately after application. Where bracken litter was applied the soil pH fell immediately; in contrast, S took at least six months to start reducing pH. Where mixtures were applied there was a synergistic effect, which produced a lower pH than the S or bracken litter applied alone. These effects were most marked at low S application rates, between 0.5–4 t S/ha. The effects of the bracken litter addition also reduced the growth of ruderal species in the period immediately after application, probably through a combination of acidification and physical smothering. There is, therefore, a clear potential to acidify ex‐arable soils using combinations of S and bracken litter in schemes designed to restore Calluna heathland.     

三唑磷的杀螨活性及其与水胺硫磷复配的增效作用

三唑磷和水胺硫磷以及它们的复配制剂对拈全瓜啭进行室内毒力测定,表明三唑磷的毒力明显大于水胺硫磷,两种药剂的各种复配均对枯全爪螨存在着不同程度的增效作用,其中以三唑磷和水胺硫磷按1：4的比例复配增效作用最为明显,共毒系数达到258。田间药效试验也表明,30%的混剂乳油(6％三唑磷 24％水胺硫磷)1000倍液的药技明显高于40%的水胺硫磷1000倍液乳油,而与20％的三唑磷乳油1000倍液相当。     

Medicines,shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures

Analytical monitoring surveys routinely confirm that organisms in the environment are exposed to complex multi-component pharmaceutical mixtures. We are hence tasked with the challenge to take this into consideration when investigating the ecotoxicology of pharmaceuticals. This review first provides a brief overview of the fundamental approaches for mixture toxicity assessment, which is then followed by a critical review on the empirical evidence that is currently at hand on the ecotoxicology of pharmaceutical mixtures. It is concluded that, while the classical concepts of concentration addition and independent action (response addition) provide a robust scientific footing, several knowledge gaps remain. This includes, in particular, the need for more and better empirical data on the effects of pharmaceutical mixtures on soil organisms as well as marine flora and fauna, and exploring the quantitative consequences of toxicokinetic, toxicodynamic and ecological interactions. Increased focus should be put on investigating the ecotoxicology of pharmaceutical mixtures in environmentally realistic settings.     

Synergism between fungal enzymes and bacterial antibiotics may enhance biocontrol

The interactions between biocontrol fungi and bacteria may play a key role in the natural process of biocontrol, although the molecular mechanisms involved are still largely unknown. Synergism can occur when different agents are applied together, and cell wall degrading enzymes (CWDEs) produced by fungi can increase the efficacy of bacteria. Pseudomonas spp. produce membrane-disrupting lipodepsipeptides (LDPs) syringotoxins (SP) and syringomycins (SR). SR are considered responsible for the antimicrobial activity, and SP for the phytotoxicity. CWDEs of Trichoderma spp. synergistically increased the toxicity of SP_25-A or SR_E purified from P. syringae against fungal pathogens. For instance, the fungal enzymes made Botrytis cinerea and other phytopathogenic fungi, normally resistant to SP_25-A alone, more susceptible to this antibiotic. Pseudomonas produced CWDEs in culture conditions that allow the synthesis of the LDPs. Purified bacterial enzymes and metabolites were also synergistic against fungal pathogens, although this mixture was less powerful than the combination with the Trichoderma CWDEs. The positive interaction between LDPs and CWDEs may be part of the biocontrol mechanism in some Pseudomonas strains, and co-induction of different antifungal compounds in both biocontrol bacteria and fungi may occur. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synergistic interaction between two bacterial isolates in the degradation of carbofuran

The dominant bacteriaPseudomonas sp. andArthrobacter sp. were isolated from the standing water of carbofuran-retreatedAzolla plot.Arthrobacter sp. hydrolysed carbofuran added to the mineral salts medium as a sole source of carbon and nitrogen while no degradation occurred withPseudomonas sp. Interestingly, when the medium containing carbofuran was inoculated with bothArthrobacter sp. andPseudomonas sp., a synergistic increase in its hydrolysis and subsequent release of CO₂ from the side chain was noticed. This synergistic interaction was better expressed at 25° C than at 35° C. Likewise, related carbamates, carbaryl, bendiocarb and carbosulfan were more rapidly degraded in the combined presence of both bacterial isolates.     

Recombinant human granulocyte-colony stimulating factor and recombinant human macrophage-colony stimulating factor synergize in vivo to enhance proliferation of granulocyte-macrophage, erythroid, and multipotential progenitor cells in mice

Combinations of low dosages of purified recombinant human (rh) macrophage-colony stimulating factor (M-CSF; also termed CSF-1) and rh granulocyte-colony stimulating factor (G-CSF) were compared alone and in combination for their influence on the cycling rates and numbers of bone marrow and splenic granulocyte-macrophage, erythroid, and multipotential progenitor cells in vivo in mice pretreated with iron-saturated human lactoferrin (LF). LF was used to enhance detection of the stimulating effects of exogenously added CSFs. Concentrations of each CSF that were not active in vivo when given alone were active when given together, with the other CSF. The concentrations of rhM-CSF and rhG-CSF needed to increase progenitor cell cycling in the marrow and spleen were reduced by factors of 40-200 when these CSFs were administered in combination with low dosages of the other CSF. At the concentrations of rhM-CSF and rhG-CSF tested, synergism was not noted on absolute numbers of progenitor cells or total nucleated cell counts per organ or circulating in the blood. These findings may have potential relevance when considered in a clinical setting where the CSFs might be used in combination with other biotherapy and/or chemotherapy.     

垂直绿化生态效益研究综述

全球气候变化和城市化背景下城市生态环境问题越发凸显,面对日趋紧张的土地资源现状,垂直绿化建设成为重要的城市绿地补充手段,对改善城市环境具有重要意义。垂直绿化具有多种生态效益,且其效益发挥受到多因素共同影响。如何统筹协调生态效益和影响因素之间的复杂关系,以使其综合生态效益最大化,是当前垂直绿化建设亟待解决的科学问题之一。基于文献综述法归纳了不同生态效益的机制及其关键影响因素,并对多效益和多影响因素进行了综合分析。结果表明,垂直绿化具有缓解城市热岛、建筑节能减排、固碳、净化空气、降噪、截留雨水和支持生物多样性等七种主要生态效益,并受到植被特征、设施结构特征、气象条件、空间格局等多方面因素的共同影响。基于对效益和影响因素的综合分析,进一步提出了两点规划思路：首先,关注环境需求和效益供给的耦合关系能够更加科学合理地指导区域垂直绿化建设布局。其次,关注生态效益间的关系,以区域关键生态环境问题为导向进行效益权衡并结合考虑其影响因素的重要性程度能为规划设计提供有效建议。     

Purification and Properties of Allothreonine Aldolase from Maise Seedlings

In order to elucidate the structure-activity relationship of griseofulvin (1), (±)-6′-demethyl analog (3), 2′-demethoxy-6′-demethyldihydro analog (4), (±)-dechloro-6′-ethyl analog (5), (±)-dechloro-6′-epi-ethyl analog (6), (±)-6′-ethyl analog (7) and (±)-6′-epi-ethyl analog (8) were synthesized by a Diels-Alder cycloaddition of alkylidene ketones (16, 17, 18, 19 and 20) with modified 1,3-butadienes (21 or 22). Their biological activities were examined against fungi.     

Impact of inter-subunit interactions on the dimeric arginine kinase activity and structural stability

Arginine kinase (AK) is a key enzyme for cellular energy metabolism, catalyzing the reversible phosphoryl transfer from phosphoarginine to ADP in invertebrates. In this study, the inter-subunit hydrogen bonds between the Q53 and D200 and between D57 and D200 were disrupted to explore their roles in the activity and structural stability of Stichopus japonicus (S. japonicus) AK. Mutating Q53 and/or D57 to alanine (A) can cause pronounced loss of activity and substrate synergism, and cause distinct conformational changes. Spectroscopic experiments indicated that mutations destroying the inter-subunit hydrogen bonds impaired the structure of dimer AK, and resulted in a partially unfolded state. The inability to fold to the functional compact state made the mutants prone to be inactivated and aggregate under environmental stresses. Restoring hydrogen bonds in Q53E and D57E mutants could rescue the loss of activity and substrate synergism, and conformational changes. All those results suggested that the inter-subunit interactions played a key role in keeping the activity, substrate synergism and structural stability of dimer AK. The result herein may provide a clue in understanding the folding and self-assembly processes of oligomeric proteins.