稻田CH4和N2O排放关系及其微生物学机理和一些影响因子

用静态箱法原位观测和分析了我国北方稻田3～12月CH₄和N₂O的排放及其关系,并研究了这一关系发生的微生物学机理.同时,监测了土壤湿度、pH、水分及Eh的变化.结果表明,稻田CH₄和N₂O排放之间存在着互为消长的关系(R²=0.0494).土壤湿度、pH及Eh变化范围分别在0～24℃、6.87～7.02和415～300mv之间,水分从非淹水期的38～72%FC至5～10cm浅水淹灌.土壤Eh对CH₄和N₂O的释放起重要的调控作用.在整个观测期内,与CH₄和N₂O释放密切相关的6种菌群(发酵细菌、产氢产乙酸细菌、产甲烷细菌、甲烷氧化菌、硝化细菌、反硝化细菌)各有其数量消长及酶活性变化规律,稻田CH₄和N₂O排放之间互为消长的关系受这些相关微生物数量及酶活性变化的共同调控.     

广州地区晚稻田CH4和N2O的排放通量及其影响因素

用密闭箱法同时研究了广州地区晚稻田CH4和N2 O的排放通量。结果表明 ,连续淹水、常规连作和水旱轮作等 3种处理的CH4平均排放通量分别为 1 7 63、2 84和0 36mg·m- 2 ·h- 1 ,而N2 O的平均排放通量分别为 6 74、1 1 69和 55 0 7μgN2 O N·m- 2 ·h- 1 ,表明稻田连续淹水显著增加CH4的排放而降低N2 O的排放。水旱轮作降低CH4排放而提高N2 O的排放 ,说明稻田CH4和N2 O排放之间存在着消长关系。讨论了这 2种温室气体排放的影响因素 ,并初步分析了它们对温室效应的相对贡献。     

华东稻麦轮作生态系统的N2O排放研究

根据对华东稻麦轮作周期的N2 O排放及其影响因子的连续观测结果 ,分析了N2 O排放时间变化以及施肥、灌溉、温度、土壤湿度和土壤速效N素含量对N2 O排放的影响 ,同时还比较分析了稻田N2 O和CH4排放 .研究结果表明 ,稻麦轮作周期内 ,水稻生长季的N2 O排放量仅占 30 % ,稻田持续淹水可比常规灌溉增加CH4排放量 2 6% ,减少N2 O排放量 1 1～ 2 6% .     

黑土稻田CH4与N2O排放及减排措施研究

通过对黑土稻田CH₄和N₂O排放的观测,发现水稻生长季CH₄和N₂O排放量低于全国其它地区稻田CH₄和N₂O排放之间存在互为消长关系(r=-0．513,P<0．05),但在同样施肥水平条件下,间歇灌溉与长期淹灌相比,CH₄排放明显减少而N₂O略有增加,其相对综合温室效应被大大减少且水稻产量未受影响。为此,间歇灌溉可作为减少稻田温室气体排放的水分管理措施。另外,通过对CH₄和N₂O排放的相关微生物过程探讨,揭示产甲烷菌数与CH4排放问呈显著性正相关(R²=0．82,P<0．05),硝化菌数和反硝化菌数与N2O排放有重要关系。     

不同水分管理下稻田土壤CH4和N2O排放与微生物菌群的关系

采用MPN计数法对黑土(海伦)和草甸棕壤(沈阳)稻田生长季4种微生物菌群数量进行了测定,同时采用封闭式箱法对CH4和N2O通量进行观测,以深入了解稻田生物源温室气体排放的微生物学过程,两地试验田均采用长期淹灌与间歇灌溉两种不同水分管理,对实验结果多元回归分析,结果表明,海伦与沈阳两地稻田两种水分管理条件下CH4通量季节变化与产甲烷菌数季节变化存在极显著正相关关系沈阳稻田生长季CH4通量季节变化与甲烷氧化菌数季节变化具有显著正相关性,间歇灌溉条件下黑土稻田N2O通量与反硝化菌数呈显著性正相关关系,两种水分管理条件下沈阳稻田N2O通量与硝化菌数具有显著正相关关系,间歇灌溉条件下沈阳稻田N2O通量与反硝化菌数呈显著性正相关关系。     

鼎湖山针阔叶混交林地表温室气体排放的日变化

利用静态箱 -气相色谱法对鼎湖山针阔叶混交林地表 3种温室气体 CO2 、CH4 、N2 O通量进行了原位观测 .结果表明 ,鼎湖山针阔叶混交林地表为 CO2 、N2 O的排放源 ,为 CH4 的弱汇 ,通量日变幅分别是 4 88.99～ 70 0 .5 7,0 .0 4 9～ 0 .10 8mg/ (m2· h)和- 0 .0 2 5～ - 0 .0 5 3mg/ (m2 · h) ;地表凋落物分解释放 CO2 约占总排放的 1/ 3;凋落物层和林下灌木对 CH4 和 N2 O的通量无明显影响 ;CO2 、N2 O的 9∶ 0 0观测值与其日平均值有明显差异     

大气氮沉降对森林土壤甲烷吸收和氧化亚氮排放的影响及其微生物学机制

水分非饱和的森林土壤是大气甲烷(CH4)汇和氧化亚氮(N2O)源,大气氮沉降增加是导致森林土壤碳氮气体通量不平衡的主要原因之一。土壤CH4吸收和N2O排放之间存在协同、消长和随机等复杂的耦合关系,关于氮素对两者产生过程的调节作用以及内在的微生物学机制至今尚不完全清楚。综述了森林土壤CH4吸收和N2O排放耦合过程的理论基础,土壤CH4和N2O的产生与消耗过程对增氮响应的生物化学和微生物学机制,指出各研究领域的不足和未来的研究重点。总体而言,低氮倾向于促进贫氮森林土壤CH4吸收,不改变土壤N2O的排放,而高氮显著抑制富氮森林土壤CH4吸收以及促进N2O排放。外源性氮素通过竞争抑制和毒性抑制来调控森林土壤CH4的吸收,而通过促进土壤硝化和反硝化过程来增加N2O的排放。然而,由于全球氮沉降控制试验网络分布的不均匀性、土壤碳氮通量产生过程的复杂性以及微生物分子生态学方法的局限性等原因,导致氮素对森林土壤碳氮通量的调控机制研究一直进展缓慢,未能将微生物功能群落动态与土壤碳氮通量真正地联系起来。未来研究应该从流域、生态系统和分子尺度上深入探讨土壤碳氮通量耦合作用的环境驱动机制,氮素对土壤CH4氧化和N2O产生过程的调控作用,以及增氮对土壤甲烷氧化菌和N2O产生菌活性和群落组成的影响。     

华南丘陵地区农林复合生态系统晚稻田甲烷和氧化亚氮排放

采用静态箱-气相色谱法对晚稻田甲烷(CH4)和氧化亚氮(N2O)排放进行田间原位测定。结果表明,有植株参与的稻田CH4排放通量季节变化与地下5cm温度呈显著正相关关系。稻田CH4和N2O季节平均排放通量在有植株参与时分别为1.16±0.38mgm-2h-1和42.33±20.00μgm-2h-1,而无植株参与的分别为0.15±0.11mgm-2h-1和51.69±15.87μgm-2h-1。水稻种植对CH4的排放影响较大,对N2O的排放影响较小,有植株参与的稻田CH4平均排放量显著高于无植株参与的稻田,N2O的平均排放量无显著差异。     

开放式空气CO2增高对稻田CH4和N2O排放的影响

在FACE(free aircarbondioxideenrichment)平台上 ,采用静态暗箱 气相色谱法观测研究了大气CO2 浓度增加对稻田CH4和N2 O排放的影响 .结果表明 ,在 15 0和 2 5 0kgN·hm-2 两种氮肥水平下大气CO2 浓度增加 2 0 0 μmol·mol-1均明显促进水稻生长 ,水稻生物量积累 .大气CO2 浓度增加对 15 0和 2 5 0kgN·hm-2 两种氮肥水平下稻田CH4排放均无显著影响 ,并简要分析了与现有文献报道结果不一致的原因 .大气CO2 浓度增加也未导致 15 0和 2 5 0kgN·hm-2 两种氮肥水平下稻田N2 O排放的明显变化 ,与大多数研究结果一致 .     

DCD不同施用时间对水稻生长期CH4和N2O排放的影响

硝化抑制剂传统的施用方法是在作物移栽或播种前与基肥配合施用.通过温室盆栽试验研究相同施肥条件下,硝化抑制剂双氢胺(dicyandiamide, DCD)不同施用时间(与基肥混施、分孽肥后施入、穗肥后施入)对水稻生长期CH4和N2O排放的影响.结果表明,施入DCD能同时降低CH4和N2O排放量.就整个水稻生长期而言,与基肥混施DCD分别降低21.41%的CH4排放量和8.00%的N2O排放量;调节DCD施用时间至分孽肥后显著降低30.30%的N2O排放量,同时降低5.24%的CH4排放量.就施入DCD到水稻收获的特定生长阶段而言,缓施DCD分别降低32.65%的N2O排放量和11.18%的CH4排放量;晚施DCD对CH4和N2O排放的影响不大.CK、早施DCD、缓施DCD及晚施DCD处理CH4平均排放通量分别为0.95、0.75、0.87 mg/(m2 · h)及0.94 mg/(m2 · h),N2O平均排放通量为155.67、143.24、108.50 μg/(m2 · h)及153.24 μg/(m2 · h),缓施DCD显著降低CH4和N2O排放量(p＜0.01).土壤温度是影响N2O排放的主要因素,而CH4排放通量与土壤Eh呈显著负相关(p＜0.01).     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Cytoskeleton and mitochondrial morphology and function

It has been well established that the cytoskeleton is an essential modulator of cell morphology and motility, intracytoplasmic transport and mitosis, however cytoskeletal linkage to the organelles has not been unequivocally demonstrated. Indeed, cytoskeleton appears to be essential in determining and modulating gene phenotype as a function of cellular environment. According to recent studies, the organization of the cytoskeleton network together with associated protein(s) could be essential in regulating mitochondrial function and particularly the permeability of the mitochondrial outer membrane to ADP. The aim of this chapter is to summarize the main properties of the cytoskeletal environment of mitochondria and the possible role(s) of this network in mitochondrial function in myocytes.     

Cross-reactivity between storage and dust mites and between mites and shrimp

Many patients have sensitivities to multiple species of storage and house dust mites. It is not clear if this is because patients have multiple sensitivities to species-specific mite allergens or if these mites share many cross-reacting allergens. Our objective was to further define the cross-allergenicity between several species of storage and house dust mites using crossed-immunoelectrophoresis (CIE), crossed-radioimmunoelectrophoresis (CRIE), immunoblotting, and ELISA. CIE and CRIE reactions revealed that storage mites shared two cross-antigenic molecules and one of these bound IgE in a serum pool from mite allergic patients. Antibody in anti-sera built to each species of mite recognized many SDS–PAGE resolved proteins of other mite species and this suggested the potential for other cross-reactive allergens. Among patient sera, IgE bound to many different proteins but few had IgE that bound to a protein with common molecular weights across the mite species and this suggested mostly species-specific allergens. Antiserum built to each mite species precipitated one protein in shrimp extracts that bound anti-Der p 10 (tropomyosin) and IgE in the serum pool. Anti-Der p 10 showed strong binding to shrimp tropomyosin but very little to any of the mite proteins. ELISA showed the mite extracts contained very little tropomyosin. The storage and dust mites investigated contain mostly species-specific allergens and very small amounts of the pan-allergen tropomyosin compared to shrimp and snail.