Assessing amendment properties of digestate by studying the organic matter composition and the degree of biological stability during the anaerobic digestion of the organic fraction of MSW

The transformation of organic matter during anaerobic digestion of mixtures of energetic crops, cow slurry, agro-industrial waste and organic fraction of municipal solid waste (OFMSW) was studied by analysing different samples at diverse points during the anaerobic digestion process in a full-scale plant. Both chemical (fiber analysis) and spectroscopic approaches (¹³C CPMAS NMR) indicated the anaerobic digestion process proceeded by degradation of more labile fraction (e.g. carbohydrate-like molecules) and concentration of more recalcitrant molecules (lignin and non-hydrolysable lipids). These modifications determined a higher degree of biological stability of digestate with respect to the starting mixture, as suggested, also, by the good correlations found between the cumulative oxygen uptake (OD₂₀), and the sum of (cellulose + hemicellulose + cell soluble) contents of biomasses detected by fiber analysis (r = 0.99; P < 0.05), and both O–alkyl-C (r = 0.98; P < 0.05) and alkyl-C (r = −0.99; P < 0.05) measured by ¹³C CPMAS NMR.     

Chromosome numbers and meiotic analysis in the pre-breeding of <Emphasis Type="BoldItalic">Brachiaria decumbens</Emphasis> (Poaceae)

A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.     

Perspective on the use of humic acids from biomass as natural surfactants for industrial applications

In the context of renewable vs. non-renewable sources of chemical compounds, the development of natural surfactants as a substitute for synthetic surfactants in technological applications is an important issue. In addition, as synthetic surfactants can persist in the environment causing toxic effects, the use of natural products presents a possibility to minimize impact on the environment. Nowadays, a promising new approach in surfactant-based technologies, consists of the use of humic acids (HAs) extracted directly from biomass that exhibit amphiphilic properties, and can be conveniently used as environmentally friendly surfactants. The raw material from which HAs are extracted and their macromolecular composition affect surfactant properties. Therefore fundamental data from more strictly qualitative aspects, needs to be investigated. This review highlights surfactant ability and chemical properties of HA substances coming from renewable sources in comparison to synthetic surfactants, and points out the capacity for HAs to be used effectively in this field of application.     

Odours and volatile organic compounds emitted from municipal solid waste at different stage of decomposition and relationship with biological stability

Odours (OU_E) and volatile organic compounds (VOC) emission during biological process used to treat MSW were studied under standardized conditions in order to detect potential risk for workers and population. Results obtained indicated that odours and VOCs emitted depend on the biological stability of waste measured by the dynamic respiration index (DRI) and a very good correlation were found between these parameters (OU_E vs. DRI, r = 0.96, p < 0.001, n = 6; VOC vs. DRI, r = 0.97, p < 0.001, n = 6).GC-MS study of the VOCs indicated the presence of a group of molecules that were degraded during the process. On the other hand, a second group of molecules, i.e. aromatic and halogenated compounds, and furan persisted in the waste sample, although molecule concentrations were always lower than Threshold Limit Value-Time Weighted Average (TLV-TWA).     

Lectin-binding sites on the plasma membranes of rabbit spermatozoa: Changes in surface receptors during epididymal maturation and after ejaculation

Modifications in rabbit sperm plasma membranes during epididymal passage and after ejaculation were investigated by used of three lectins: concanavalin A (Con A); Ricinus communis I (RCA(I)); and wheat germ agglutinin (WGA). During sperm passage from caput to cauda epididymis, agglutination by WGA drastically decreased, and agglutination by RCA(I) slightly decreased, although agglutination by Con A remained approximately unchanged. After ejaculation, spermatozoa were agglutinated to a similar degree or slightly less by Con A, WGA, and RCA(I), compared to cauda epididymal spermatozoa. Ultrastructural examination of sperm lectin-binding sites with ferritin- lectin conjugates revealed differences in the densities of lectin receptors in various sperm regions, and changes in the same regions during epididymal passage and after ejaculation. Ferritin-RCA(I) showed abrupt changes in lectin site densities between acrosomal and postacrosomal regions of sperm heads. The relative amounts of ferritin-RCA(I) bound to heads of caput epididymal or ejaculated spermatozoa. Tail regions were labeled by ferritin RCA(I) almost equally on caput and cauda epididymal spermatozoa, but the middle-piece region of ejaculated spermatozoa was slightly more densely labeled than the principal-piece region, and these two regions on ejaculated spermatozoa were labeled less than on caput and cuada epididymal spermatozoa. Ferritin-WGA densely labeled the acrosomal region of caput epididymal spermatozoa, although labeling of cauda epidiymal spermatozoa was relatively sparse except in the apical area of the acrosomal region. Ejaculated spermatozoa bound only a few molecules of ferritin-WGA, even at the highest conjugate concentrations used. Caput epididymal, but not cauda epididymal or ejaculated spermatozoa, bound ferritin-WGA in the tail regions. Dramatic differences in labeling densities during epididymal passage and after ejaculation were not found with ferritin-Con A.     

H－ras在颊粘膜正常、良性、癌前及恶性变上皮中的表达：免疫组织化学定量研究

本文通过建立图象分析方法对免疫组织化学反应结果进行定量,检测观察Ｈ－ｒａｓ在口腔颊粘膜上皮在正常（Ｎ）、慢性炎症（ＩＦ）、癌旁上皮（ＥＡＣ）和鳞癌（ＳＣＣ）的变化过程中的表达并进行分析。结果显示Ｈ－ｒａｓ在ＳＣＣ组中,以中等分化的ＳＣＣ无论是Ｈ－ｒａｓ表达的量还是细胞阳性率都较高。此外,组织学观察显示,Ｈ－ｒａｓ在处于分化末期但尚未角化的正常上皮细胞中有较高的表达。本文结果显示了Ｈ－ｒａｓ的过表达与上皮细胞的会化程度密切相关。本研究还显示,所采用的阳性区域透光值、平均总透光值及阳性反应区域与阴性反应区域比值可靠并有相关性。这进一步说明了用免疫组化定量方法检测Ｈ－ｒａｓ癌基因表达的精确和可靠性。     

Structural chemistry of sulfonated fluorobenzylphosphonate salts. I

A study of the salts of 4-fluoro-3-sulfobenzylphosphonic acid has resulted in the synthesis of two new compounds with unusual layered structures. The crystal structures of these salts and the parent acid have been determined by single crystal X-ray methods. Crystal data: 4-F-3-SO₃H-C₆H₃CH₂PO₃H₂·H₂O: triclinic, space group

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for 1519 observations (l>3σ(l)) and 182 variables; [Ni(NH₃)₂(H₂O)₄]₃(4-F-3-SO₃-C₆H₃-CH₂PO₃)₂·4H₂O: triclinic, space group

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for 2689 observations (l>3σ(I)) and 511 variables: Na₃(4-F-3-SO₃-C₆H₃CH₂PO₃)- 8.5H₂O: monoclinic, C2/c, Z = 8, A = 25.636(4), B = 6.218(4), C = 24.136(2) Å, β = 98.33(1)°, V = 3807(3) ų, R(F) = 0.047 for 2262 observations (I>2;3σ(I)) and 254 variables. The parent acid monohydrate crystallizes in layers with the acidic groups directed to the faces of the layer. The water molecules are in between the layers hydrogen-bonded to the sulfonate oxygen atoms. The nickel salt contains three independent cations, each of which is hexacoordinated to a mixture of water and ammonia molecules. Thus, there is no direct coordination of the nickel by either the sulfonate or phosphonate oxygen atoms. The structure has alternating layers, the first formed by the anions and one of the nickel complexes, and the second by the other two complexes and the free water molecules. The sodium salt also has the anions arranged in layers but with an interpenetrating three-dimensional network of ionic and hydrogen bonds involving the cations and water molecules. The sodium ions are coordinated to a mixture of sulfonate oxygen atoms and bridging water molecules in irregular six-fold environments. These structures are discussed in terms of the coordination behavior of the difunctional anions in the context of known monofunctional phosphonate and sulfonate compounds.     

Biogas from dedicated energy crops in Northern Italy: electric energy generation costs

Agricultural anaerobic digestion facilities are increasing in many EU member States and biomass supply is sometimes an issue. Dedicated energy crops (DEC) (mainly Maize, Triticale and Sorghum) are often used to integrate other substrates, such as agricultural residues, manure and organic waste. However, DEC production includes onerous agricultural operations (soil preparation, harvest, transport and storage) and may result in high unit costs (UC) of electric energy (EE, € kWhe⁻¹), compared to other renewable sources. In this work, seven different types of DEC (4 different combinations of crop successions) were cultivated in 30 different parcels, distributed along the Po Valley (northern Italy), using different varieties of seeds for each crop type. All agricultural operations were accounted for their costs (988–3346 € ha⁻¹). Biomass production was measured and reported as average of different parcels for each type of crop (31.2–187 Mg ha⁻¹). Biomass dry matter content and biogas potential were measured on representative samples and the EE obtainable was calculated (7.9–35.3 MWhe ha⁻¹), by assuming conservative factors (CH₄ contents in biogas and electric generation yields). The costs of ensiled biomass sensibly varied (13.8–40 € Mg⁻¹) among crop solutions, as well as the same UC of EE (0.068–0.150 € kWhe⁻¹). These costs were considered together with typical plant management and investment costs (plant size: 0.5–1 MWe): total UC of EE generation through anaerobic digestion (considering 100% DEC) varied in a relatively wide range (0.143–0.279 € kWhe⁻¹). When the biomass mix is ‘blended’ with low-cost residues or organic waste, this range could be lowered to 0.096–187 € kWhe⁻¹. Only this strategy and strong efforts in reducing technological investment/management costs can candidate biogas-based EE as a really competitive renewable alternative to traditional sources, in the next future.     

游仆虫信息素Er-1和Er-2对四膜虫的种间作用

信息素是生物体向外释放的化学物质,在细胞及生物体中具有种内信息传递的生理学功能。信息素这一类分子广泛分布于系统发生史中,它们的特异活性在单细胞生物、昆虫以及脊椎动物中均有报道。脊椎动物中信息素的信号传输已被证实是一嗅觉依赖过程,7TM-受体被认为是信号传输过程中的信号转换器。在低等单细胞生物(例如:来可夫游仆虫)的细胞膜上存在有信息素异构体,作为信息素分子的有效结合位点而行使其功能。本研究主要探讨单细胞的信息素(Er-1和Er-2)的基础细胞生理学作用是仅限于产生该信息素的物种,还是对其它的原生动物(例如:四膜虫)或对系统发育中分类地位较高的细胞(例如:MRC5成纤维细胞或J774巨噬细胞)均具有调节活性。研究结果表明,游仆虫的两种信息素对梨形四膜虫GL的生长调节有显著不同的作用:当信息素浓度为10-11M时,Er-1具有正调控作用,而Er-2具有抑制剂的作用。这两种配体的趋化作用也有很不同:Er-1具有一种广范的化学排斥特性,而Er-2具有一个双峰的化学吸引剂的性质。计算机检测发现,与Er-2的作用不同,Er-1可略微降低被测细胞的游动速率。趋化现象的选择特性表明Er-2信息素的受体有一种“短期”的特性;而Er-1是不能选择任何亚种群的,这也支持了我们先前的研究数据,即这两种信息素在四膜虫GL内产生两种不同的信号。四膜虫对信息素特异性的反应表明四膜虫能辨别非常近似但带有微小差异的配体(如Er-1和Er-2的电荷差异)。     

Rock weathering creates oases of life in a High Arctic desert

During primary colonization of rock substrates by plants, mineral weathering is strongly accelerated under plant roots, but little is known on how it affects soil ecosystem development before plant establishment. Here we show that rock mineral weathering mediated by chemolithoautotrophic bacteria is associated to plant community formation in sites recently released by permanent glacier ice cover in the Midtre Lovénbreen glacier moraine (78°53′N), Svalbard. Increased soil fertility fosters growth of prokaryotes and plants at the boundary between sites of intense bacterial mediated chemolithotrophic iron‐sulfur oxidation and pH decrease, and the common moraine substrate where carbon and nitrogen are fixed by cyanobacteria. Microbial iron oxidizing activity determines acidity and corresponding fertility gradients, where water retention, cation exchange capacity and nutrient availability are increased. This fertilization is enabled by abundant mineral nutrients and reduced forms of iron and sulfur in pyrite minerals within a conglomerate type of moraine rock. Such an interaction between microorganisms and moraine minerals determines a peculiar, not yet described model for soil genesis and plant ecosystem formation with potential past and present analogues in other harsh environments with similar geochemical settings.