The contribution of<Emphasis Type="Italic"> Phragmites australis</Emphasis> litter to methane (CH<Subscript>4</Subscript>) emission in planted and non-planted fen microcosms   总被引：1，自引：0，他引：1  

Sari?JuutinenEmail author  Tuula?Larmola  Rainer?Remus  Edith?Mirus  Wolfgang?Merbach  Jouko?Silvola  Jürgen?Augustin 《Biology and Fertility of Soils》2003,38(1):10-14

The contribution of Phragmites australis (Cav.) Trin. ex Steud. (common reed) litter as an origin of CH ₄-C was studied in a microcosm experiment. ¹⁴C-labelled, dried and ground P. australis root and shoot litter was buried in waterlogged, planted or non-planted fen microcosms. The evolution of ¹⁴CO ₂ and ¹⁴CH ₄ from the pots was monitored during the 35-day experiment. The ¹⁴C activity in the shoots and roots of the plants, soil, and inundation water was also analysed at the end of the experiment. Up to 40% of the released CH ₄-C originated from the added litter, whereas the rest originated from old soil organic matter. The comparison of planted and non-planted pots suggested that the contribution of recent plant-derived C (i.e. root exudates) to CH ₄ emission was negligible. The proportion of litter-derived CH ₄-C was significantly higher in the planted pots, suggesting that the presence of plants enhanced the formation of CH ₄ from litter. The major part of the initial ¹⁴C activity was recovered from the soil. About 3% was recovered from the inundation water, about 10% was emitted as CO ₂, and only <0.01% as CH ₄. However, these results demonstrated that plant litter and old soil organic matter are the major sources of CH ₄-C in fens during the early growth stage of P. australis.  相似文献   

Dendritic cell stimulation by mycobacterial Hsp70 is mediated through CCR5     

Floto RA  MacAry PA  Boname JM  Mien TS  Kampmann B  Hair JR  Huey OS  Houben EN  Pieters J  Day C  Oehlmann W  Singh M  Smith KG  Lehner PJ 《Science (New York, N.Y.)》2006,314(5798):454-458

An effective host immune response to mycobacterial infection must control pathogen dissemination without inducing immunopathology. Constitutive overexpression of mycobacterial heat shock protein (myHsp70) is associated with impaired bacterial persistence, but the immune-mediated mechanisms are unknown. We found that myHsp70, in addition to enhancing antigen delivery to human dendritic cells, signaled through the CCR5 chemokine receptor, promoting dendritic cell aggregation, immune synapse formation between dendritic cells and T cells, and the generation of effector immune responses. Thus, CCR5 acts as a pattern-recognition receptor for myHsp70, which may have implications for both the pathophysiology of tuberculosis and the use of myHsps in tumor-directed immunotherapy.  相似文献   

Physicochemical and Enzyme Characterization of Small and Large Starch Granules Isolated from Two Maize Cultivars     

Rubí G. Utrilla‐Coello  Edith Agama‐Acevedo  Ana Paulina Barba de la Rosa  Sandra L. Rodríguez‐Ambriz  Luis Arturo Bello‐Prez 《Cereal Chemistry》2010,87(1):50-56

In this study, some morphological, physicochemical, and the initial characterization of the starch granule enzymes of blue and white maizes of small and large granules are described. Starch was isolated from blue and white maizes, and the small and large granules were separated. The efficiency of separation was higher in large granules than small of the blue maize starch. The amylose content was slightly greater (1.3%) in large granules than smaller in both starches studied. No differences in the average gelatinization temperature were found between large and small granules, but the enthalpy of gelatinization value was higher in the small granules. The electrophoretic pattern showed that the granule‐bound starch synthase (GBSSI) had higher expression in large than small granules and that explain the higher amylose content in the former granules. The differences showed in the starch biosynthesis enzymes in small and large granules might explain partially the physicochemical and functional properties of maize.  相似文献   

Identifying nitrogen-efficient potato cultivars for organic farming     

Marjolein Tiemens-Hulscher  Edith T. Lammerts van Bueren  Paul C. Struik 《Euphytica》2014,199(1-2):137-154

In organic farming, nitrogen efficiency of potato might vary among cultivars, even within the same maturity type. We therefore analysed in depth the response to nitrogen of a diverse set of cultivars, grown at different locations (differing in soil type and management) and in four years (differing in temperature and rainfall patterns). Yield increased with an increase in nitrogen supply and with growing later cultivars if the crop cycle lasted long enough. When crops had to be flamed to prevent spread of late blight, late cultivars yielded less than early cultivars, especially under high nitrogen. By measuring the fraction of soil covered by green leaves throughout the growing season and using a model, we analysed canopy development in detail and related nitrogen and genotype sensitive model parameters to tuber yield. In one year with early, temporary drought, model prediction was poor. We observed that cultivars that rapidly established a high maximum soil cover, maintained that maximum for long and senesced slowly, could sustain high yields. When late-blight infection was late, these (mid)-late cultivars showed high agronomic nitrogen use efficiency, but were not (always) high in nitrogen uptake efficiency, accumulation of nitrogen in the tubers or nitrogen utilisation efficiency. When late-blight infection started early, early or mid-late cultivars that rapidly established a high maximum soil cover under low nitrogen availability gave best performance. In most years, early canopy development is responsive to nitrogen, shows genetic variation, and is significantly related to early tuber yield. Nitrogen-efficient cultivars suitable for organic production should have rapid early canopy development, a high agronomic nitrogen use efficiency and nitrogen utilisation efficiency, but a low nitrogen concentration in the tubers.  相似文献   

Physicochemical Properties of Oat Varieties and Their Potential for Breadmaking     

Edith K. Hüttner  Fabio Dal Bello  Emanuele Zannini  Jean Titze  Steffen Beuch  Elke K. Arendt 《Cereal Chemistry》2011,88(6):602-608

The breadmaking potential of six oat varieties was compared with and related to their physicochemical properties. The most significant differences in the bread characteristics were found in the crumb structure. The varieties Buggy, Energie, and Zorro resulted in good bread quality with an even gas‐cell distribution characterized by a high number of relatively small pores. In contrast, Typhon, Ivory, and Nord 08/311 each had a large hole in the center of the crumb and accordingly poor quality. Breads differed little in specific volume, bake loss, and density. Rheological analysis revealed positive effects of low batter resistance to deformation on oat bread quality. On the basis of the physicochemical characterization, protein and fat contents were identified as key factors responsible for differences observed in bread quality, provided that starch damage and water‐hydration capacity were low. Additionally, high setback and final viscosity, as determined by Rapid Visco Analyser (RVA) analysis, positively affected oat bread quality. High α‐amylase activity was found to influence negatively the breadmaking performance of oats. Overall, protein, fat, dietary fiber content, starch pasting properties, and α‐amylase activity were responsible for the breadmaking properties of oat varieties.  相似文献   

Biodegradability of Disinfectants in Surface Waters from Buenos Aires: Isolation of an Indigenous Strain Able to Degrade and Detoxify Benzalkonium Chloride     

María Susana Fortunato  Sabina Baroni  Ana Julieta González  Jesús David Álvarez Roncancio  Mariana Papalia  Manuela Martinefsky  Valeria Trípodi  Estela Planes  Alfredo Gallego  Sonia Edith Korol 《Water, air, and soil pollution》2018,229(4):120

Biodegradability of chlorhexidine (CH), triclosan (TC), and benzalkonium chloride (CBA) has been tested in 18 surface water sampling points in the urban area of Buenos Aires. Sampling points were located in both the Reconquista and the Matanza-Riachuelo basins as well as in the La Plata River. High tolerance to the three disinfectants was found and indigenous strains capable of degrading CBA and TC were isolated. Neither tolerance nor biodegradation were correlated with sewage pollution. A strain that degrades CBA was identified as belonging to the genus Pseudomonas using the API20NE system and 16SRNA sequencing. In batch assays, the strain was capable of degrading 100, 200, and up to 500 mg L^?1 of CBA in 10, 25, and 46 h respectively with specific growth rates (μ) of 0.56, 0.30, and 0.14 h^?1. The efficiency of the process was between 99.5–98.0% in terms of compound removal and between 93.8–89.1% in terms of chemical oxygen demand (COD). The detoxification of the compound as a result of the biodegradation was assessed using Pseudokirchneriella subcapitata, Vibrio fischeri, and Lactuca sativa as test organisms.  相似文献   

Marine myxobacteria as a source of antibiotics--comparison of physiology, polyketide-type genes and antibiotic production of three new isolates of Enhygromyxa salina     

Schäberle TF  Goralski E  Neu E  Erol O  Hölzl G  Dörmann P  Bierbaum G  König GM 《Marine drugs》2010,8(9):2466-2479

Three myxobacterial strains, designated SWB004, SWB005 and SWB006, were obtained from beach sand samples from the Pacific Ocean and the North Sea. The strains were cultivated in salt water containing media and subjected to studies to determine their taxonomic status, the presence of genes for the biosynthesis of polyketides and antibiotic production. 16S rDNA sequence analysis revealed the type strain Enhygromyxa salina SHK-1(T) as their closest homolog, displaying between 98% (SWB005) and 99% (SWB004 and SWB006) sequence similarity. All isolates were rod-shaped cells showing gliding motility and fruiting body formation as is known for myxobacteria. They required NaCl for growth, with an optimum concentration of around 2% [w/v]. The G + C-content of genomic DNA ranged from 63.0 to 67.3 mol%. Further, the strains were analyzed for their potential to produce polyketide-type structures. PCR amplified ketosynthase-like gene fragments from all three isolates enhances the assumption that these bacteria produce polyketides. SWB005 was shown to produce metabolites with prominent antibacterial activity, including activity towards methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE).  相似文献   

Risk-based surveillance for avian influenza control along poultry market chains in South China: The value of social network analysis   总被引：1，自引：0，他引：1  

Martin V  Zhou X  Marshall E  Jia B  Fusheng G  FrancoDixon MA  DeHaan N  Pfeiffer DU  Soares Magalhães RJ  Gilbert M 《Preventive veterinary medicine》2011,102(3):196-205

Over the past two decades, the poultry sector in China went through a phase of tremendous growth as well as rapid intensification and concentration. Highly pathogenic avian influenza virus (HPAIV) subtype H5N1 was first detected in 1996 in Guangdong province, South China and started spreading throughout Asia in early 2004. Since then, control of the disease in China has relied heavily on wide-scale preventive vaccination combined with movement control, quarantine and stamping out. This strategy has been successful in drastically reducing the number of outbreaks during the past 5years. However, HPAIV H5N1 is still circulating and is regularly isolated in traditional live bird markets (LBMs) where viral infection can persist, which represent a public health hazard for people visiting them. The use of social network analysis in combination with epidemiological surveillance in South China has identified areas where the success of current strategies for HPAI control in the poultry production sector may benefit from better knowledge of poultry trading patterns and the LBM network configuration as well as their capacity for maintaining HPAIV H5N1 infection. We produced a set of LBM network maps and estimated the associated risk of HPAIV H5N1 within LBMs and along poultry market chains, providing new insights into how live poultry trade and infection are intertwined. More specifically, our study provides evidence that several biosecurity factors such as daily cage cleaning, daily cage disinfection or manure processing contribute to a reduction in HPAIV H5N1 presence in LBMs. Of significant importance is that the results of our study also show the association between social network indicators and the presence of HPAIV H5N1 in specific network configurations such as the one represented by the counties of origin of the birds traded in LBMs. This new information could be used to develop more targeted and effective control interventions.  相似文献   

Effects of different organic materials and mineral nutrients on arbuscular mycorrhizal fungal growth in a Mediterranean saline dryland     

Edith C. Hammer  Hafedh Nasr 《Soil biology & biochemistry》2011,43(11):2332-2337

Arbuscular mycorrhizal (AM) fungi are root symbionts that enhance plant growth and improve soil fertility and soil structure in drylands. Even though AM fungi are obligate biotrophs, organic matter (OM) can stimulate their growth, but the mechanisms behind this are still unknown. Here, we compared the effect of nutrient patches of different OM sources to intrinsic components of OM such as inorganic nutrient supply and an improved soil water-holding capacity (WHC; via application of hydrophilic polymers), on AM fungal growth. Fatty acids extracted from in-growth mesh bags incubated in the field were used as biomarkers for AM fungi and other soil microbes. We found an enhancement of AM fungal growth in certain nutrient patches. Two out of three OM types stimulated AM fungal growth strongly, and also the addition of inorganic nutrients enhanced AM fungi, though to a lesser extent than OM. Enhanced soil WHC, on the other hand, did not influence AM fungal growth. AMF were more strongly enhanced by the mineral nutrients relative to other soil organisms. Intrinsic nutrients might be an important factor for AMF growth stimulation in OM additions, but there was no evidence that nutrients alone can explain this phenomenon.  相似文献   

Fundamental evaluation of the impact of high Hydrostatic Pressure on oat batters   总被引：1，自引：0，他引：1  

Edith K. Hüttner  Fabio Dal Bello  Kaisa Poutanen  Elke K. Arendt   《Journal of Cereal Science》2009,49(3):363-370

The use of grains alternative to wheat or rye is a challenging task for cereal technologists, and currently new technologies are under investigation as tools to improve the performances of these alternative grains. In this work the effects of high Hydrostatic Pressure (HP) on oat batters were investigated. Oat batters were treated for 10 min at 200, 300, 350, 400 or 500 MPa. Scanning electron microscopy and bright field microscopy showed that high HP significantly affected oat batter microstructure, and both starch and proteins were affected. Treatment at high HP significantly improved batter viscosity and elasticity. At pressures ≤300 MPa the increase in the viscous component was higher than the increase in the elastic component. On the contrary, at pressures ≥350 MPa the elastic component was predominant. Differential scanning calorimetry revealed that high HP induced starch gelatinisation, which started at 300 MPa and was almost complete after treatment at 500 MPa. High HP also affected water- and salt-soluble as well as urea-soluble oat proteins. Analysis of proteins soluble in different buffers revealed that pressures ≥300 MPa induced the formation of urea-insoluble complexes and/or disulfide bonds. Overall, the extent of starch gelatinisation and protein modification was dependent on the applied pressure, but the results collected so far clearly show that high HP can be used to improve the functionality of oat batters.  相似文献