Methylated anthocyanidin glycosides from flowers of Canna indica

Methylated anthocyanin glycosides were isolated from red Canna indica flower and identified as malvidin 3-O-(6-O-acetyl-β-d-glucopyranoside)-5-O-β-d-glucopyranoside (1), malvidin 3,5-O-β-d-diglucopyranoside (2), cyanidin-3-O-(6″-O-α-rhamnopyranosyl-β-glucopyranoside (3), cyanidin-3-O-(6″-O-α-rhamnopyranosyl)-β-galactopyranoside (4), cyanidin-3-O-β-glucopyranoside (5) and cyanidin-O-β-galactopyranoside (6) by HPLC-PDA. Their structures were subsequently determined on the basis of spectroscopic analyses, that is, ¹H NMR, ¹³C NMR, HMQC, HMBC, ESI-MS, and UV-vis. Compounds (1-4) were found to be in major quantity while compounds (5-6) were in minor quantity.     

芭蕉芋叶片结构特征及其与抗旱性的关系

运用石蜡切片法和指甲油印迹法,对3个芭蕉芋品种的叶片解剖结构——叶片厚度、叶肉厚度、上表皮厚度、下表皮厚度、气孔密度、气孔长度及宽度、长细胞长度及宽度、短细胞长度及宽度等10项相关指标进行测定,分析芭蕉芋抗旱性与叶片结构之间的关系。结果表明:(1)芭蕉芋的表皮结构与抗旱性有一定的关系,表现为抗旱性强的品种气孔密度大,且长、短细胞体积小、排列紧密。(2)芭蕉芋叶片、叶肉、上下表皮厚度与抗旱性关系在不同品种间差异不显著。(3)芭蕉芋叶肉及上、下表皮占叶片横切面的比例与抗旱性存在显著相关关系。(4)芭蕉芋叶片保水能力与叶肉比例呈极显著负相关关系,与上表皮比例呈极显著正相关关系。     

Polysaccharide isolated from Passiflora edulis: Characterization and antitumor properties

A hot water-extracted polysaccharide fraction (PFCM) of Passiflora edulis was characterized by microanalysis, infrared spectroscopy, NMR and high performance size-exclusion chromatography. The major component in PFCM is (1 → 4) linked galacturonic acid (esterified and unesterified). Neutral sugars such as arabinose, glucose, rhamnose, mannose, and fucose were also present. Traces of xylose and ribose were detected. The PFCM sample had a similar molar mass to that of pectin extracted from P. edulis under acidic conditions. Sarcoma 180 tumors treated with PFCM showed a growth inhibition ratio ranging from 40.59% to 48.73% depending on the dosage and type of PFCM administration (oral or intraperitoneal). Toxicological analysis shows that PFCM increases the cell types involved in primary defense mechanisms and no significant changes in the biochemical parameters and organs (e.g., kidney and liver) were observed. However, the use of PFCM treatment increased the spleen weight when compared with the use of 5-fluorouracil.     

毛竹浸提液对苦槠幼苗生长的化感效应

为探讨毛竹(Phyllostachys edulis)扩张过程中潜在的化感作用,选择苦槠(Castanopsis sclerophylla(Lindl)Schott)为研究对象。采用水浸提的方法,用毛竹茎叶、枯落物和土壤3部分浸提液浇灌苦槠幼苗,以蒸馏水处理作为对照,对比分析质量浓度分别为0.1、0.05、0.02 g/mL的3个浓度梯度浸提液处理下苦槠幼苗生长指标及各项光合生理指标的差异。结果表明,毛竹浸提液对苦槠幼苗苗高、地径和叶绿素相对含量的影响大体上呈现高浓度抑制低浓度促进的双重浓度效应。不同来源毛竹浸提液的化感效应不尽相同,土壤浸提液对苦槠幼苗生长和光合生理均呈现抑制作用,而茎叶、枯落物浸提液低浓度时为促进作用。毛竹潜在的化感作用,在其扩张过程中可能会干扰森林主要树种更新,从而对森林群落产生威胁。     

Soluble and surface-bound aminopeptidase in eosinophilic blood cells from Mytilus edulis

This study focused on soluble and surface-bound aminopeptidase (AP) in hemocytes from Mytilus edulis and on the identification of the enzyme-producing blood cells. The cell extract hydrolyzed alanine p-nitroanilide (Ala-pNA) with an optimum between pH 6.4 and 7.0. Following native gradient PAGE of extract, alanyl methoxy-naphthylamide (AMNA) was converted by one band with an estimated molecular weight of 375 kDa; it included at least ten putative AP-isozymes with isoelectric points between pH 4.5 and 5.8. In addition to this soluble form, electron microscopy revealed simultaneous conversion of AMNA on the surface of blood cells. Individual mussels expressed AP-molecules in 23-39% of their hemocytes. These cells were shown to represent eosinophilic granulocytes.     

毛竹PsbS基因的克隆及其原核表达特征研究

采用RT-PCR技术从毛竹(Phyllostachys edulis)叶片中克隆到1个PsbS基因,命名为PePsbS (GenBank No. FJ600727),其编码区为810 bp,编码269个氨基酸。序列分析表明,PePsbS编码的蛋白与其它单子叶植物的PsbS蛋白有很高的相似性。蛋白结构分析表明,PePsbS基因编码蛋白包含导肽部分和成熟蛋白,其中成熟蛋白包含4个跨膜结构域。将PePsbS基因编码成熟蛋白的序列构建到原核表达载体pET23a中,并转入大肠杆菌,用IPTG进行诱导表达。结果表明, 41℃下诱导4 h的表达效果最好,目的蛋白含量约占总蛋白的21.5%,分子量约为22.0 kD。这说明温度和诱导时间明显影响PePsbS基因的表达。     

Experimental test of biodeposition and ammonium excretion from blue mussels (Mytilus edulis) on eelgrass (Zostera marina) performance

Blue mussels and eelgrass have been found to coexist in many locations. However, knowledge of the interactions between these species is limited. Two experiments were conducted in the laboratory, a “Deposit” and an “Epiphyte” experiment. The Deposit experiment examined possible effects of increasing load of blue mussel (Mytilus edulis) biodeposits on sediment biogeochemistry and eelgrass (Zostera marina) performance. Z. marina mesocosms received normal or high loads of mussel biodeposits (Normal and High), while no biodeposits were added to the Control. High dosage had overall negative effects on Z. marina, which was reflected as lower leaf numbers and biomass and accumulation of elemental sulphur in rhizomes. The sediment biogeochemical conditions were altered, as the mussel biodeposits enhanced sulphate reduction rates and increased sulphide concentrations in the porewater, which may result in sulphide invasion and reduced growth of Z. marina.In the Epiphyte experiment effects of mussel excretion, with particular emphasis on ammonium, on the growth of Z. marina and their epiphytes were examined. A thick cover of epiphytes developed on Z. marina growing together with M. edulis, and the relative growth rate was reduced with 20% compared to plants from control without mussels. Overall the experiments showed negative effects on Z. marina growing together with M. edulis, thereby supporting a preceding field study by Vinther et al. [Vinther, H.F., Laursen, J.S., Holmer, M. 2008. Negative effects of blue mussel (Mytilus edulis) presence in eelgrass (Zostera marina) beds in Flensborg fjord, Denmark. Est. Coast Shelf. Sci. 77, 91-103.].     

Nocardiosis in Mediterranean bivalves: First detection of Nocardia crassostreae in a new host Mytilus galloprovincialis and in Ostrea edulis from the Gulf of Naples (Italy)

In this work M. galloprovincialis and O. edulis specimens were surveyed for a pathological study in the Gulf of Naples (Mediterranean sea, Campania Region, southern Italy). Clusters of Nocardia sp.-like cells were observed in histological slides. PCR amplification, sequencing and in situ hybridization were carried out in order to corroborate Nocardia species identification for both hosts. Blast results showed a 99% of maximum identity with Nocardia crassostreae sequences in Genbank. This is the first report of N. crassostreae in the new host M. galloprovincialis and, in a new area, the Mediterranean Sea.     

The effect of salinity change on the heart rate of Mytilus edulis specimens from different ecological zones

The heart rate of specimens of Mytilus edulis (L.) both from the sublittoral and littoral zones exposed to normal and altered salinity was investigated in a long-term experiment. The heart rate was monitored by a non-invasive method for nine days. The heart rate of sublittoral mussels was higher than that of littoral ones. This suggests a higher level of metabolic activity in sublittoral mussels. When exposed to moderate hyposalinity (15 g l⁻¹) M. edulis from both zones showed a significant decrease in the heart rate with respect to the control salinity (25 g l⁻¹), but sublittoral mussels had a more prominent bradycardia. The heart beat quickly accelerated in all organisms when they were returned to the control salinity medium. Throughout the experiment, heart contractions halted with distinct periodicity in all mussels.     

Feeding behavior and differential absorption of biochemical components by the infaunal bivalve Mulinia edulis and the epibenthic Mytilus chilensis in response to changes in food regimes

We measured changes in the feeding rate and food absorption efficiency of two suspension feeding bivalves, cross-trasplanted between habitats with special emphasis on their capacity for differential absorption of biochemical components from their food supply. Mulinia edulis were moved from the intertidal zone to the subtidal zone, and Mytilus chilensis from the subtidal to the intertidal zone for a period of 7 days, and then compared with animal that had not been transplanted. Experimentally prepared diets similar to those available in the two different environments were offered to the bivalves, and their rates of feeding and differential uptake of biochemical components were determined and statistically compared. The two species did not achieve complete acclimation of their feeding behaviour during the transplant period since the highest ingestion rates for biochemical components occurred under dietary conditions that reflected their habitats of origin. Absorption efficiency showed greater acclimation than the other physiological parameters measured, indicating the capacity of these species to modulate their enzymatic-digestive activity depending on food composition. We conclude that both Mytilus and Mulinia have a certain degree of physiological plasticity in their feeding behaviour and assimilatory balance of biochemical components, being greater in Mytilus. When both species encounter ambient food conditions characteristic of their normal habitats, they show maximum values of food absorption, while under conditions where their typical diets are exchanged (Mytilus in intertidal and Mulinia in subtidal), the energy absorbed declines in each, but in ways very different between the two species. Thus, Mytilus exposed to high concentrations of low quality seston reduced the energy absorbed by 31.7% compared to its normal habitat, while Mulinia exposed to low concentrations of high-quality food reduced their energy absorption by 64%.     

Influence of steaming explosion time on the physic-chemical properties of cellulose from Lespedeza stalks (Lespedeza crytobotrya)

The synergistic effect of steam explosion pretreatment and sodium hydroxide post-treatment of Lespedeza stalks (Lespedeza crytobotrya) has been investigated in this study. In this case, Lespedeza stalks were firstly exploded at a fixed steam pressure (22.5 kg/m²) for 2–10 min. Then the steam-exploded Lespedeza stalks was extracted with 1 M NaOH at 50 °C for 3 h with a shrub to water ratio of 1:20 (g/ml), which yielded 57.3%, 53.1%, 55.4%, 52.8%, 53.2%, and 56.4% (% dry weight) cellulose rich fractions, comparing to 68.0% from non-steam-exploded material. The content of glucose in cellulose rich residues increased with increment of the steaming time and reached to 94.10% at the most severity. The similar increasing trend occurred during the dissolution of hemicelluloses. It is evident that at shorter steam explosion time, autohydrolysis mainly occurred on the hemicelluloses and the amorphous area of cellulose. The crystalline region of cellulose was depolymerized under a prolonged incubation time. The characteristics of the cellulose rich fractions in terms of FT-IR and CP/MAS ¹³C NMR spectroscopy and thermal analysis were discussed, and the surface structure was also investigated by SEM.     

Larval recruitment of the blue mussel Mytilus edulis: The effect of flow and algae

The mussel Mytilus edulis settlement and distribution was studied on plastic panels with manipulated flow regime (faired, bluff, split and angled) with or without water soluble metabolites of the green alga Cladophora rupestris. The panels were exposed vertically on a device (hydrovane) that ensures their constant orientation in the current during the peak of larval settlement at 1 m depth. In order to investigate larval distribution on the panels, half of them were coated with a silicone vacuum grease that prevents larvae from de-attachment. This grease was not toxic and did not attract or repel larvae. Low densities of larvae on the un-greased plates compared to the greased ones suggested that some of larvae left the substratum. The blue mussel larvae initially settled in regions of reduced shear velocity and then redistribute to the regions of high shear velocity. The presence of the alga increased the density of blue mussel larvae and changed their distribution on the panels. Overall, our results demonstrated that larval recruitment of M. edulis is an active process affected both by boundary-layer hydrodynamics and algal waterborne compounds.     

Isolated and combined impacts of blue mussels (Mytilus edulis) and barnacles (Balanus improvisus) on structure and diversity of a fouling community

Effects of two presumably dominant competitors, the blue mussel Mytilus edulis and the barnacle Balanus improvisus on recruitment, population dynamics and community structure on hard substrata were experimentally investigated in the subtidal Kiel Fjord, Western Baltic. The hypothesis that blue mussels and/or barnacles are local dominants and strongly influence succession and community structure was tested by monitoring succession in the presence and absence of simulated predation on either or both species. Manipulations included blue mussel removal, barnacle removal, combined blue mussel and barnacle removal, as well as a control treatment for natural (non-manipulated) succession. In the second part of the experiment, recovery from the treatments was monitored over 1 year.During the manipulative phase of the experiment, blue mussels had a negative effect on recruitment of species, whereas barnacles had no significant effect. Even so, a negative synergistic effect of blue mussels and barnacles was detected. Calculation of species richness and diversity H′ (Shannon Index) showed a negative synergistic effect of blue mussels and barnacles on community structure. Additionally, diversity H′ was negatively affected by the dominant competitor M. edulis. These effects were also detectable in the ANOSIM-Analysis. The non-manipulative phase of the experiment brought about a drastic loss of diversity and species richness. Blue mussels dominated all four communities. Barnacles were the only other species still being able to coexist with mussels. Effects of simulated predation disappeared fast.Thus, in the absence of predation on blue mussels, M. edulis within a few months dominates available space, and diversity of the benthic community is low. In contrast, when mussel dominance is controlled by specific predators, more species may persist and diversity remains high.     

The Rieske/cytochrome b complex of Heliobacteria

Heliobacteria have a Rieske/cytochrome b complex composed of a Rieske protein, a cytochrome b_6, a subunit IV and a di-heme cytochrome c. The overall structure of the complex seems close to the b₆f complex from cyanobacteria and chloroplasts to the exception of the di-heme cytochrome. We show here by biochemical and biophysical studies that a heme c_i is covalently attached to the Rieske/cytochrome b complex from Heliobacteria. We studied the EPR signature of this heme in two different species, Heliobacterium modesticaldum and Heliobacillus mobilis. In contrast to the case of b₆f complex, a strong axial ligand to the heme is present, most probably a protonatable amino acid residue.     

CO2浓度升高对毛竹器官矿质离子吸收、运输和分配的影响

为了给大气CO2浓度逐渐升高背景下的毛竹林适应性经营管理提供理论依据,运用开顶式气室(OTCs)模拟大气CO2浓度升高(500、700 μmol/mol)情景,以目前环境背景大气为对照,研究了Na+、Fe2+-Fe3+、Ca2+、Mg2+等矿质离子在毛竹器官中吸收、运输和分配的变化规律.结果显示,除CO2浓度700 μmoL/mol对Ca2+浓度在毛竹器官中大小排序会产生影响外,CO2浓度500、700 μmol/mol并未改变毛竹器官中Na+、Fe2+,Fe3+、Mg2+、Ca2+浓度的大小排序.CO2浓度升高对竹叶Fe2+-Fe3+和竹枝Fe2+-Fe3+、Mg2+浓度无明显影响,但对器官的其它矿质离子浓度会有不同程度的影响,竹叶Ca2+和Mg2+、竹枝Na+和Ca2+、竹秆Na+和Ca2+及Mg2+、竹根Na+和Mg2+浓度明显提高,竹叶Na+、竹秆Fe2+-Fe3+、竹根Fe2+-Fe3+和Ca2+浓度明显降低;随着CO2浓度的升高,竹叶Fe2+-Fe3+/Na+、Mg2+/Na+和Ca2+/Na+,竹枝Ca2+/Mg2+及各器官Mg2+/Fe2+-Fe3+、Ca2+/Fe2+-Fe3+均逐渐增大,而竹枝、竹秆、竹根Fe2+-Fe3+/Na+、Mg2+/Na+、Ca2+/Na+和竹叶、竹秆、竹根Ca2+/Mg2+均逐渐减小;CO2浓度升高后除竹根-竹秆Sca.Na、竹秆-竹枝SMg,Fe和竹枝-竹叶Sca,Mg明显下降外,其余的毛竹器官矿质离子向上运输系数变化平缓或明显提高.研究表明CO2浓度升高增强了毛竹立竹根部积累Na+能力和Fe2+-Fe3+、Ca2+和Mg2+的向上选择性运输能力,提高了光合器官竹叶中矿质养分元素浓度,可维持体内矿质养分元素平衡,有利于提高毛竹对高浓度CO2环境的适应能力.     

Rheological behaviour and microstructure of microfibrillated cellulose suspensions/low-methoxyl pectin mixed systems. Effect of calcium ions

In this study, the influence of the presence of low-methoxyl pectin (LM pectin) on the rheological and microstructural properties of microfibrillated cellulose suspensions was elucidated in order to create new structures with new and interesting textures. For that purpose, the rheological properties of the cellulose/LM pectin mixtures in variable proportions were compared with those of the individual biopolymers. The influence of the presence of calcium and/or sodium ions on the properties of the mixed systems was studied. The microstructure of the resulting system was studied by transmission electron microscopy and confocal laser scanning microscopy. It was found that, in the presence of LM pectin, a synergistic effect was observed when calcium ions were also present, leading to increased rheological properties of the composites. Indeed, addition of calcium to the mixtures induced LM pectin gelation, which was favoured in the presence of sodium, the pectin network contributing to the formation of a stronger cellulose/LM pectin composite gel. The presence of LM pectin alone in the microfibrillated cellulose suspensions does not significantly modify the viscoelastic and microstructural properties of microfibrillated cellulose suspensions. Whether calcium was added to the mixtures or not in water, the viscoelastic properties of the mixtures are mainly controlled by cellulose. The same behaviour was observed for the mixtures in NaCl without added calcium. Contrary to this observation, it was noticed that in presence of both sodium and calcium ions, the viscoelastic properties of the mixtures are largely governed by LM pectin. On the other hand, it was showed that the flow behaviour of microfibrillated cellulose suspensions is modified in the presence of LM pectin with an increase in thixotropic character shear-thinning behaviour, which was more pronounced in the presence of NaCl. It was also shown, from TEM observations, that an interpenetrating network formed in cellulose/LM pectin composites gel in the presence of calcium ions. In the same way, the CLSM observations allowed the separate localization of cellulose and LM pectin within the composite systems to be highlighted. The results obtained suggests that it is possible to thus create new structures with new interesting textures, by mixing microfibrillated cellulose suspensions and LM pectin in suitable proportions in the simultaneous presence of both sodium and calcium ions.     

Distribution and diversity of members of the bacterial phylum Fibrobacteres in environments where cellulose degradation occurs

The Fibrobacteres phylum contains two described species, Fibrobacter succinogenes and Fibrobacter intestinalis, both of which are prolific degraders of cellulosic plant biomass in the herbivore gut. However, recent 16S rRNA gene sequencing studies have identified novel Fibrobacteres in landfill sites, freshwater lakes and the termite hindgut, suggesting that members of the Fibrobacteres occupy a broader ecological range than previously appreciated. In this study, the ecology and diversity of Fibrobacteres was evaluated in 64 samples from contrasting environments where cellulose degradation occurred. Fibrobacters were detected in 23 of the 64 samples using Fibrobacter genus-specific 16S rRNA gene PCR, which provided their first targeted detection in marine and estuarine sediments, cryoconite from Arctic glaciers, as well as a broader range of environmental samples. To determine the phylogenetic diversity of the Fibrobacteres phylum, Fibrobacter-specific 16S rRNA gene clone libraries derived from 17 samples were sequenced (384 clones) and compared with all available Fibrobacteres sequences in the Ribosomal Database Project repository. Phylogenetic analysis revealed 63 lineages of Fibrobacteres (95% OTUs), with many representing as yet unclassified species. Of these, 24 OTUs were exclusively comprised of fibrobacters derived from environmental (non-gut) samples, 17 were exclusive to the mammalian gut, 15 to the termite hindgut, and 7 comprised both environmental and mammalian strains, thus establishing Fibrobacter spp. as indigenous members of microbial communities beyond the gut ecosystem. The data highlighted significant taxonomic and ecological diversity within the Fibrobacteres, a phylum circumscribed by potent cellulolytic activity, suggesting considerable functional importance in the conversion of lignocellulosic biomass in the biosphere.     

The contribution of marine snow to the particle food supply of the benthic suspension feeder, Mytilus edulis

In order to examine the importance of the settling of large particles to the food supply and feeding behavior of a benthic culture of the blue mussel, Mytilus edulis, we investigated the tidal dynamics of large (>0.5 mm diameter) marine aggregates, commonly known as marine snow, during three tidal cycles in July 1998 at a shallow, subtidal, low current flow regime site along the coast of Maine (Shorey Cove, Roque Island, Englishman's Bay, Maine).In situ, optically measured marine snow showed a distinct tidal signal displaying an increase in size and abundance through high tide with a peak on the early ebb tide as it settled to the bottom. Marine snow volume ranged an order of magnitude through the tidal cycle, from under 8 to over 80 mm³ l⁻¹. An increase in the in situ marine snow volume corresponded with an increase in benthic mussel feeding activity (from 20% to 60% of maximum exhalant siphon area, which is an estimate of pumping rate) and maximum rates of pseudofeces production by the mussels during periods of low tidal current speeds. In contrast, mussels from the same population feeding on surface waters in shipboard chambers produced no pseudofeces and had high pumping rates (80-100% maximum exhalant siphon area) over the whole tidal period. A second peak in benthic mussel pumping rates also occurred during flood tide.Food quality was lower in the bottom waters due to significantly higher particulate inorganic matter (PIM, >2 mg l⁻¹) when compared with the surface waters. PIM accounted for 95% of the total settled mass flux of 3.4 g m⁻² day⁻¹ measured in sediment traps deployed 1 m off the bottom, with organic carbon representing only 2.5% of the mass flux during the mid-summer conditions. At low-current sites such as Shorey Cove, Roque Island, Maine, the settling of marine snow provides an important additional source of food, albeit of low quality, to benthic populations of blue mussels.