南亚热带乡土树种人工纯林及混交林土壤微生物群落结构

以我国南亚热带格木、马尾松人工纯林及二者混交林林地土壤为对象,运用磷脂脂肪酸(PLFAs)法研究了3种人工林土壤微生物生物量和群落结构特征.结果表明: 旱季土壤微生物的PLFAs总量及各菌群的PLFAs量显著高于雨季.旱季土壤微生物的PLFAs总量、细菌PLFAs量、真菌PLFAs量、放线菌PLFAs量均为马尾松人工林最高,混交林次之,格木林最低;而雨季格木人工林土壤微生物的PLFAs总量、细菌PLFAs量、真菌PLFAs量、丛枝菌根真菌PLFAs量高于混交林,并显著高于马尾松人工林.主成分分析表明,土壤微生物群落结构组成受林分类型和季节的双重影响.冗余分析表明,土壤温湿度、pH值、全氮及铵态氮含量与特征磷脂脂肪酸之间呈显著相关关系.在全年水平上,混交林土壤真菌/细菌比值始终高于格木林和马尾松林,表明格木与马尾松混交更有利于提高土壤生态系统的稳定性.     

不同发育阶段杉木人工林对土壤微生物群落结构的影响

采用变性梯度凝胶电泳技术(DGGE),分析土壤细菌16S rDNA和土壤真菌28SrDNA特异性片段多态性,研究了不同发育阶段杉木人工林对土壤微生物群落结构的影响.结果表明:土壤微生物群落结构随着杉木人工林的发育年龄而改变,杉木人工林土壤微生物群落多样性和丰富度随杉木生长发育显著增加(P<0.05),但均显著低于次生阔叶林(P<0.05);聚类分析表明,不同发育阶段杉木人工林土壤真菌群落相似性均<60%,而土壤细菌群落相似性最高可达65%,由此可推测不同发育阶段杉木人工林土壤真菌群落结构变化较土壤细菌群落结构变化剧烈;相关性分析表明,不同发育阶段杉木人工林土壤速效氮、碳氮比与土壤微生物群落多样性显著相关(P<0.05).本研究表明,长期种植单一杉木人工林能够通过改变土壤理化性质来影响土壤微生物群落组成,进而影响森林生态系统养分循环,导致人工林林分生产力下降.     

城市森林土壤微生物群落结构的季节变化

土壤微生物在森林生态系统中扮演重要的角色,是森林生态系统中物质循环的驱动因素,但目前对于城市森林土壤微生物群落的季节变化及其影响因素研究较少。因此,本研究以东莞城市森林为对象,采用高通量测序方法研究城市森林土壤微生物的季节变化规律及其影响因素。结果表明:土壤微生物群落结构和多样性有显著的季节变化,湿季土壤微生物总数量显著低于干季,但湿季土壤微生物Chao1指数和Shannon指数显著高于干季,湿季细菌和真菌的多样性和菌群结构更为丰富,其中细菌主要通过数量改变适应季节的变化,真菌主要通过数量以及物种组成的改变适应季节变化。土壤有效硼是细菌群落结构的主要影响因子,pH是真菌群落结构的主要影响因子,土壤中交换性钙和交换性镁亦是影响细菌和真菌群落的重要因子。     

树种丰富度和组成对南亚热带人工林土壤植物源碳保存及有机碳稳定性的影响

混交造林能显著提高森林生产力和土壤碳储量。然而，不同树种丰富度和组成如何影响土壤中植物源碳保存和有机碳稳定性仍不清楚。以南亚热带不同树种组配的人工林生态系统为研究对象，采用角质-叶源和木栓质-根源生物标志物研究树种丰富度和组成变化对土壤中叶和根源碳保存和降解的影响，并量化了它们对土壤有机碳稳定性的贡献。结果表明，树种丰富度增加，木栓质含量显著增加，但对角质含量无显著影响。相比之下，不同树种组成显著影响角质含量，但对木栓质含量无显著影响。土壤pH和含水量主要影响角质含量，而土壤全氮和真菌/细菌丰度显著影响木栓质含量。角质和木栓质的降解参数ω-C₁₆/∑C₁₆和ω-C₁₈/∑C₁₈与树种丰富度和树种组成均无关，主要受土壤pH、铵态氮、碳氮比的显著影响。结构方程模型结果表明角质组分对土壤有机碳稳定性指标易氧化有机碳与总有机碳比值(EOC/SOC)具有直接正效应，而木栓质组分对EOC/SOC具有直接负效应。树种丰富度可以通过增加细根生物量和真菌/细菌丰度促进土壤中根源碳组分的保存，从而提高土壤有机碳稳定性。...     

杉木人工林土壤质量演变过程中土壤微生物群落结构变化

以中国科学院会同森林生态站自然林、杉木连栽林和杉木阔叶树混交林地土壤为研究对象,采用PCR-DGGE、DNA-sequencing和主成分分析(PCA)等方法分析土壤微生物群落结构变化及其与土壤质量变化之间的关系.结果表明,该地区杉木人工林土壤中细菌优势种群为α-、β-、γ-proteobacteria和Cytophaga-Flexibacter-Bacterioides (CFB)类群;真菌优势种群为子囊菌(Ascomycetes)和担子菌(Basidiomycetes)亚门的种属.杉木人工林替代自然林后,土壤细菌多样性指数显著降低,且随连栽代数增加呈持续降低趋势;杉木人工林土壤中与Pedobacter cryoconitis亲缘关系密切的细菌种群消失,出现与Xanthomonas sp.和Rhodanobacter sp.亲缘关系密切的细菌种群.土壤真菌群落结构的变化与细菌相反,杉木人工林替代自然林后并不断连栽时,土壤真菌多样性指数呈现上升的趋势,自然林土壤中优势真菌种群在杉木三代林中消失.杉木与火力楠或桤木混交后土壤细菌和真菌种群结构与自然林类似.土壤细菌多样性指数与土壤总有机碳、全氮、可溶性有机碳、铵态氮、速效磷、速效钾含量以及土壤pH值呈显著正相关关系(P＜0.05).土壤真菌多样性指数仅与土壤碳氮比呈显著正相关关系,而与土壤pH值呈显著负相关关系.杉木林土壤质量变化对土壤细菌和真菌优势种群有较大影响,细菌Burkholderia sp.、Pedobactersp.、Xanthomonas sp.和真菌Sclerotinia sclerotiorum、Mycosphaerella cannabis可能是引起土壤质量变化的关键种群.     

贺兰山不同林分凋落物微生物群落特征与影响因素

贺兰山是我国重要生态屏障,贺兰山生态森林生态系统保护受到极大关注,森林凋落物及土壤微生物对全球气候变化研究具有重要意义。目前,贺兰山不同林分的凋落物分解过程中微生物群落结构特征差异、不同凋落物化学组成对微生物群落结构的影响尚不清楚。以贺兰山具有代表性的3种林分（油松林、青海云杉林以及油松-山杨混交林）凋落物为研究对象,开展凋落物化学组成、微生物群落组成及多样性特征研究,揭示不同林分凋落物的优势微生物群落特征和影响因子。结果表明,3种林分凋落物的细菌和真菌在多个多样性指数之间差异性均不显著,但是在多样性指数中真菌PD whole tree指数显著大于细菌,真菌Shannon指数与Ghao1指数却显著小于细菌。在门水平上不同林分凋落物的微生物优势菌类无显著差异,但在属水平上差异显著,而且细菌差异小于真菌,在各个分类水平上,凋落物细菌和真菌群落组成均表现为油松-山杨混交林＜青海云杉林＜青海云杉林,凋落物微生物多样性在青海云杉林中最为丰富。细菌不同节点间连接线负相关数量略大于正相关,真菌则相反。油松林凋落物与其它林分凋落物相比,微生物群落之间联系更加紧密。油松林凋落物OC含量最大、青海云杉林凋落物的TK含量最大、油松-山杨混交林的TN含量最大,且在3种林分中显著差异。相关性分析表明OC、TN、TP、TK是影响凋落物细菌和真菌群落组成及多样性的主要因素,冗余分析表明不同林分凋落物的微生物多样性指数受养分影响,凋落物OC、TN、TP、TK是影响微生物群落组成和多样性的重要因素,其中OC与微生物群落多样性相关性最显著,是影响凋落物细菌和真菌群落组成和多样性最主要的因子。     

云南松林次生演替阶段土壤细菌群落的变化

土壤细菌多样性是维持森林生态系统功能的关键因子,森林演替是影响其动态变化的重要因素。研究云南松林不同演替阶段土壤细菌群落结构及其多样性的变化规律,有助于深入理解森林生态系统恢复过程的驱动机制。本研究以云南省永仁县皆伐后形成的针叶林、针阔混交林和常绿阔叶林为对象,基于Illumina Hiseq高通量测序技术,分析森林演替过程中土壤细菌群落组成、结构、多样性及其影响因子的变化。结果表明: 土壤细菌的种群分类单元、Ace指数、Chao1指数和Shannon指数均随着演替进行呈减少趋势,演替早期阶段土壤的细菌总数、菌群丰富度及复杂程度最高。不同演替阶段细菌群落结构存在显著差异,其中,针阔混交林的差异最大,变形菌门和酸杆菌门为各演替序列共有的优势类群,放线菌门、绿弯菌门和Patescibacteria是演替早期的优势类群,且随着演替进行呈现减少趋势;变形菌门和WPS-2相对多度随演替进行呈增加趋势。土壤pH和乔木层物种丰富度是驱动次生演替过程中土壤细菌群落组成变化的关键因子。随着演替的进行,土壤细菌多样性减少,群落组成差异加大。     

南亚热带森林演替过程中土壤线虫群落结构变化

森林演替会通过改变植物群落组成和土壤环境影响土壤生物群落, 反过来, 土壤生物群落的变化也会对生态系统的演替产生反馈作用, 但迄今南亚热带森林演替过程中土壤生物群落的变化特征尚不清晰。本研究以广东省鼎湖山的南亚热带森林演替序列(马尾松(Pinus massoniana)林-针阔叶混交林-季风常绿阔叶林)为对象, 研究了森林演替过程中土壤线虫多样性和群落结构的动态变化及其影响因素。通过采集不同演替阶段的土壤样品, 分析和比对了不同演替阶段土壤线虫的多度、多样性、群落组成、土壤线虫生态指数以及土壤理化性质的差异。结果表明: (1)在南亚热带森林演替过程中, 针阔叶混交林和季风常绿阔叶林土壤线虫的α多样性显著高于马尾松林, 但土壤线虫总数和各营养类群多度及其相对丰度并无显著变化; (2)针阔叶混交林中土壤线虫富集指数显著高于马尾松林, 表明其土壤养分状况要好于马尾松林, 而季风常绿阔叶林土壤线虫结构指数较高, 表明其受干扰程度较低; (3)针阔叶混交林的土壤含水量和土壤理化性质(除土壤总磷含量)已达到季风常绿阔叶林的水平, 但两者的土壤pH值均显著低于马尾松林, 而土壤pH值和土壤含水量是影响土壤线虫群落动态变化的主要因素。综上所述, 南亚热带森林中土壤线虫多度、多样性和群落结构对森林演替的响应略有不同, 演替过程中土壤环境因素的趋同是导致针阔叶混交林和季风常绿阔叶林中土壤线虫多样性和群落特征相似的主要原因。     

树种多样性对土壤微生物群落结构和元素生物地球化学循环的影响研究进展

森林是陆地生态系统的重要组成部分,其巨大的生产力和生态服务功能对人类的生存和发展至关重要。森林树种多样性增加能够显著提高森林生产力,关于树种多样性如何影响地下生物多样性及生态功能逐渐受到国内外学者的广泛关注。从土壤微生物及其介导的元素生物地球化学循环这一视角出发,综述了树种多样性对土壤细菌和真菌多样性、群落结构及功能的影响,提出需要进一步深入研究的方向。总体来说,树种多样性有利于增加土壤细菌生物量和多样性,是预测病原性真菌和菌根真菌多样性及群落结构的重要生物因子。树种多样性能增加土壤有机碳储量,增强森林土壤的甲烷氧化能力,并提高土壤磷周转速率及有效磷含量。关于树种多样性对森林土壤氮循环的影响需考虑多样性假说和质量比假说的相对贡献。今后应加强树种多样性对多个营养级之间相互作用的研究;关注树种多样性对生态系统多功能的影响;加强学科交叉,引入微生物种群动态模型和气候模型等模型预测方法,研究树种多样性对全球气候变化的应对机制,以期促进地上植物多样性与地下生态系统功能关系的研究,增强森林生态系统应对未来全球环境变化的能力。     

不同混交措施下杉木人工林群落稳定性特征

混交是人工林近自然经营的重要措施,探究混交度和树种配置对杉木人工林群落稳定性的影响可以为构建可持续经营的杉木混交林提供依据。本研究以3种不同混交度(纯林/低度0.051、中度0.297、高度0.598)的杉木人工林为研究对象,以林内优势种的更新潜力、林地生产力、土壤肥力和物种多样性等4类指标12个因子为评价标准,对不同人工林的群落稳定性特征进行分析。结果表明:与杉木纯林相比,混交林的林下更新潜力分别提高了32%(中混交度)和100%(高混交度),更新幼苗的种类也更为丰富。其次,混交林的草本生物量和物种丰富度均高于纯林,但乔木树种的生物量却分别仅有纯林的58%(中混交度)和66%(高混交度)。此外,混交林较高的物种丰富度和林下更新能力,增加了对土壤养分的需求,其土壤肥力较纯林略低。应用模糊数学中隶属函数方法对各林地群落稳定性进行综合评价,结果表明,中度混交林地的群落稳定性最高(0.909),其次为高混交度林地(0.882),而纯林的稳定性最低,仅为0.856。因此,构建密度适宜的杉木-檫木-栎属树种中度混交林可以使杉木人工林朝着健康的森林演替方向发展,使森林群落的经济和生态效益得到持续发挥。     

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.     

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.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.     

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.     

Antibacterial and Antifugal Mono- and Di-substituted Symmetrical and Unsymmetrical Triazine-derived Schiff-bases and their Transition Metal Complexes

A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements. IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies show the metal complexes to be more antibacterial/antifungal against two or more species as compared to the uncomplexed Schiff-base ligands.