Element turnover in a heavily damaged Norway spruce ecosystem influenced by N deposition

Element budgets of a heavily damaged Norway spruce ecosystem at Hohe Matzen in the Fichtel Mountains/FRG were studied over 3 years. The trees show severe symptoms of decline and Mg deficiency. The soil is a typic Dystrochrept derived from granite with sandy texture, high stone content, and low base saturation. The budgets show high releases of N, S and Al from the ecosystem as a result of input, buffering and turnover processes. After an increase of proton fluxes in the organic surface layer, a strong reduction of protons in the B horizon was found. This process was accompanied by the release of Al, whereas reactive Al(OH)₃ was exhausted in the A horizon. The low ANC is also shown in pH-stat.-titrations. The data indicate a strong mineralisation in the humus layer, which results in a net release of NH₄, SO₄ and TOC. Nitrification takes place mainly in the A horizon. With respect to the N-budget, the ecosystem is approaching the state of N saturation. The processes of N turnover lead to an internal proton production exceeding the atmospheric input, and thus contributing to soil acidification.     

Interrelationship between lignin deposition and the activities of peroxidase isoenzymes in differentiating tracheary elements of Zinnia

In a culture system in which single cells isolated from the mesophyll of Zinnia elegans L. differentiate to tracheary elements (TEs), two inhibitors of phenylalanine ammonia-lyase (EC 4.3.1.5), L-α-aminooxy-β-phenylpropionic acid (AOPP) at 10 μM inhibited lignification without reducing the number of TEs formed. These inhibitors caused intracellular changes in peroxidase (EC 1.11.1.7) activities. The inhibitors increased the activity of peroxidases bound to the cell walls and especially the activity of peroxidase bound ionically to the cell walls. In contrast, the activity of extracellular peroxidase decreased. There were five isoenzymes, P1-P5, in the ionically bound peroxidase of cultured Zinnia cells. Among the isoenzymes, P4 and P5 appeared to be specific for TE differentation. Treatment with AOPP and AIP resulted in increases in the activities of P2, P4 and P5 isoenzymes, with the most prominent increase in P5 activity. The addition of lignin precursors, including coniferyl alcohol, to the AOPP-treated cells restored lignification, and suppressed the alteration of peroxidase isoenzyme patterns caused by AOPP. The relationship between the wall-bound peroxidases and lignification during TE differentiation is discussed in the light of these results.     

Fine structure of aphid stylet routes in plant tissues in correlation with EPG signals

Abstract. Plant penetration by Aphis fabae (Scopoli) was recorded by the electrical penetration graph (EPG) technique and followed by stylectomy during wave-forms that were suspected of indicating sieve element punctures. The severed stylets in the plant tissue were subsequently processed for transmission electron microscopy (TEM) and sectioned either transverse or longitudinal to the stylets. Two completely serially sectioned probes from the epidermis to the phloem were reconstructed.
In one probe the stylet pathway went to a sieve element and showed many empty branches of salivary sheath material. Breaks in cell walls filled with sheath material demonstrated that the majority of cells bordering the track had been punctured, which supports earlier evidence from EPGs. All types of cells showed punctures and the highest number was found inside the vascular bundle. Very few cells died, which would appear to be important for virus transmission, and in others cellular reactions remained limited to some callose formation. The route of the stylets was intercellular and passed through the secondary wall material. The role of pectinase in intercellular penetration, and previous evidence for intracellular tracks are discussed. Most sieve elements had been punctured but only one was eventually accepted. Thus, reaching a sieve element in a host plant does not automatically imply its acceptance though the reason remains unclear. Gelation of phloem proteins was shown in the stylet canal.
In a second probe, plant cytological and morphological correlations with the EPG were emphasized. Probes by other aphid-plant combinations showed great similarity.     

江苏海岸带陆生盐土植物矿质元素含量的特点及生物循环

陆生盐土植物在生长过程中吸收积累了大量的Cl和Na;从海向陆随着土壤和植被的生态演替,植物中Cl和Na的浓度逐渐降低;N与Cl、Na有相似的水平分布规律;植物种类是影响元素吸收积累的主要因素。在盐地碱蓬中N、P、K、Ca、Mg、Na、Cl、Mn和Zn的含量均是生长前期较高,随着其生长老化逐渐降低,大穗结缕草、白茅与盐地碱蓬相比,Ca的含量前期低后期高,Na、Mn、Cu和Zn的季节变化不明显。参加盐地碱蓬系统生物循环的元素中,Cl和Na的比例最大,在大穗结缕草和白茅生态系统中比例较小;由于白茅被收割利用,一些元素从此生态系统中流失。     

海洋生物礁类型、生态功能及其生态修复

海洋生物礁是由具有造礁能力的海洋生物聚集而成的一种三维礁体结构,其形成改变了海底地貌、增加了不同尺度上的地形复杂性,为其他海洋生物提供了栖息地并维持了生物多样性。近年来,由于自然因素和人为因素影响,海洋生物礁受到了严重威胁,已成为海洋生态保护和修复领域的重要研究对象。综述了海洋生物礁的类型、生态功能及其生态修复的研究进展。根据形成海洋生物礁的优势造礁生物种类,将海洋生物礁分为海藻礁、海绵礁、刺胞动物礁、贝类礁和多毛类礁,其优势造礁生物分别是珊瑚藻和仙掌藻、钙质海绵和硅质海绵、造礁珊瑚、牡蛎、龙介虫。目前国内对海洋生物礁的全面了解相对较少,主要集中在珊瑚礁和牡蛎礁。海洋生物礁的生态功能主要有海岸防护、提供栖息地、净化水体、固碳作用和能量耦合等。全球变暖和海洋酸化等全球气候变化以及海洋污染、破坏性渔业捕捞、海岸工程、水产养殖和敌害生物等自然和人为因素对海洋生物礁构成了严重威胁。海洋生物礁的生态修复方法分为两类：在退化生物礁区投放造礁生物逐渐成礁,投放人工礁体补充造礁生物逐渐成礁。针对海洋生物礁保护和修复的需要,提出下一步应加强海洋造礁生物生态特征、海洋造礁生物种群丧失因素和海洋生物礁保护与...     

Medical application of laser-induced breakdown spectroscopy (LIBS) for assessment of trace element and mineral in biosamples: Laboratory and clinical validity of the method

BackgroundBiomedical application is based on the use of LIBS-derived data on chemical contents of tissues in diagnosis of diseases, forensic investigation, as well as a mechanism for providing online feedback for laser surgery. Although LIBS has certain advantages, the issue of correlation of LIBS-derived data on chemical element content in different human and animal tissues with other methods, and especially ICP-MS, remains pertinent. The objective of the present review was to discuss the application of laser-induced breakdown spectroscopy (LIBS) for elemental analysis of human biosamples or tissues from experimental models of human diseases. Methods. A systematic search in the PubMed-Medline, Scopus, and Google Scholar databases using the terms laser-induced breakdown spectroscopy, LIBS, metals, trace elements, minerals, and names of particular chemical elements was performed up through 25 February, 2023. Of all extracted studies only those dealing with human subjects, human tissues, in vivo animal and in vitro cell line models of human diseases were reviewed in detail. Results. The majority of studies revealed a wide number of metals and metalloids in solid tissues including teeth (As, Ag, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Ni, P, Pb, Sn, Sr, Ti, and Zn), bones (Al, Ba, Ca, Cd, Cr, K, Mg, Na, Pb, Sr), and nails (Al, As, Ca, Fe, K, Mg, Na, P, Pb, Si, Sr, Ti, Zn). At the same time, LIBS was also used for estimation of trace element and mineral content in hair (Ca, Cu, Fe, K, Mg, Na, Zn), blood (Al, Ca, Co, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Si, Sn, Zn), cancer tissues (Ca, Cu, Fe, Mg, K, Na, Zn) and other tissues. Single studies revealed satisfactory correspondence between quantitative LIBS and ICP-OES/MS data on the level of As (81–93 %), Pb (94–98 %), Cd (50–94 %) in teeth, Cu (97–105 %), Fe (117 %), Zn (88–117 %) in hair, Ca (97–99 %), Zn (90–95 %), and Pb (61–82 %) in kidney stones. LIBS also estimated specific patterns of trace element and mineral content associated with multiple pathologies, including caries, cancer, skin disorders, and other systemic diseases including diabetes mellitus type 2, osteoporosis, hypothyroidism, etc. Data obtained from in situ tissue LIBS analysis were profitably used for discrimination between tissue types. Conclusions. Taken together, the existing data demonstrate the applicability of LIBS for medical studies, although further increase in its sensitivity, calibration range, cross-validation, and quality control is required.     

法尼醇X受体激动剂细胞筛选体系的建立与优化

本研究旨在建立一种基于双荧光素酶报告基因检测体系的法尼醇X受体(farnesoid X receptor, FXR)激动剂细胞筛选体系,以满足对FXR激动剂先导化合物的高通量筛选。通过在报告基因质粒pGL4-luc2P-Hygro中的萤火虫荧光素酶(firefly luciferase,Luc)基因上游克隆并插入来自FXR靶基因的FXR反应元件(FXR response element,FXRE)片段,构建用于筛选FXR激动剂的报告基因质粒,并结合海肾荧光素酶内参质粒,建立能够有效反映药物对FXR激动效应的双荧光素酶报告基因细胞检测体系。通过一系列优化实验,比较了过表达RXR、鼠源和人源FXR、不同的FXRE片段、FXR过表达质粒与报告基因质粒的混合比对筛选体系诱导效率和灵敏度的影响。根据上述结果,最终确定了优化条件,优化后体系Z因子达到0.83。本研究建立了一种用于FXR激动剂筛选的改良的基于双荧光素酶报告基因检测体系的细胞筛选体系,其主要特征在于,使用多段FXR靶基因上的FXRE片段叠加组成一种新型的增强型FXRE元件,而非传统的反向重复序列-1 (inverted repeats...     

Osteological and histological comparison of the development of the interphalangeal intercalary skeletal element between hyloid and ranoid anurans

Some frog species have a unique skeletal element, referred to as the intercalary element (IE), in the joints between the terminal and subterminal phalanges of all digits. IEs are composed of cartilage or connective tissue and have a markedly differ shape than the phalanges. IEs are highly related to the arboreal lifestyle and toe pads. The IE is found only in neobatrachian frogs among anurans, suggesting that it is a novelty of Neobatrachia. IEs are widely distributed among multiple neobatrachian lineages and are found in the suborders Hyloides and Ranoides (the two major clades in Neobatrachia). However, it is unclear whether the IEs found in multiple linages resulted from convergent evolution. Therefore, in this study, we aimed to examine how similar or different the developmental trajectories of the IEs are between Hyloides and Ranoides. To that end, we compared the osteological and histological developmental processes of the IEs of the hyloid frog Dryophytes japonicus and the ranoid frog Zhangixalus schlegelii. Both species shared the same IE-initiation site and level of tissue differentiation around the IE when it began to form in tadpoles, although the IE developments initiated at different stages which were determined by external criteria. These results suggest that similar mechanisms drive IE formation in the digits of both species, supporting the hypothesis that the IEs did not evolve convergently.     

Empirical testing of cryoconite granulation: Role of cyanobacteria in the formation of key biogenic structure darkening glaciers in polar regions

Cryoconite, the dark sediment on the surface of glaciers, often aggregates into oval or irregular granules serving as biogeochemical factories. They reduce a glacier's albedo, act as biodiversity hotspots by supporting aerobic and anaerobic microbial communities, constitute one of the organic matter (OM) sources on glaciers, and are a feeder for micrometazoans. Although cryoconite granules have multiple roles on glaciers, their formation is poorly understood. Cyanobacteria are ubiquitous and abundant engineers of cryoconite hole ecosystems. This study tested whether cyanobacteria may be responsible for cryoconite granulation as a sole biotic element. Incubation of Greenlandic, Svalbard, and Scandinavian cyanobacteria in different nutrient availabilities and substrata for growth (distilled water alone and water with quartz powder, furnaced cryoconite without OM, or powdered rocks from glacial catchment) revealed that cyanobacteria bind mineral particles into granules. The structures formed in the experiment resembled those commonly observed in natural cryoconite holes: they contained numerous cyanobacterial filaments protruding from aggregated mineral particles. Moreover, all examined strains were confirmed to produce extracellular polymeric substances (EPS), which suggests that cryoconite granulation is most likely due to EPS secretion by gliding cyanobacteria. In the presence of water as the only substrate for growth, cyanobacteria formed mostly carpet-like mats. Our data empirically prove that EPS-producing oscillatorialean cyanobacteria isolated from the diverse community of cryoconite microorganisms can form granules from mineral substrate and that the presence of the mineral substrate increases the probability of the formation of these important and complex biogeochemical microstructures on glaciers.