Seasonal variations in location and population structure of endophytes in buds of Scots pine     

Pirttilä AM  Pospiech H  Laukkanen H  Myllylä R  Hohtola A 《Tree physiology》2005,25(3):289-297

We studied the location and distribution of a bacterial isolate, a Mycobacterium sp., in buds of Scots pine (Pinus sylvestris L.). Using a probe specific for the 16S rRNA of the Mycobacterium sp., the bacterium was found by in situ hybridization in the meristematic tissues of 40% of all bud samples examined. Because we had previously found other bacterial and fungal endophytes in the meristematic tissues of Scots pine buds, we studied their occurrence in buds during shoot development and dormancy. Using probes targeted to the 16S or 18S rRNA of the endophytes Mycobacterium sp., Methylobacterium spp., Pseudomonas spp. and Rhodotorula minuta, endophytes were found in association with growing tissues, with Methylobacterium spp. being the dominant species. Endophytes were detected in abundance before elongation or differentiation of a bud, but once a tissue was fully developed, endophytes were no longer detected. Metabolic activity of the endophytes was suppressed at the onset of, and during, dormancy of Scots pine, but recovered before the following growing season.  相似文献   

Apple polyphenols and products formed in the gut differently inhibit survival of human cell lines derived from colon adenoma (LT97) and carcinoma (HT29)     

Veeriah S  Hofmann T  Glei M  Dietrich H  Will F  Schreier P  Knaup B  Pool-Zobel BL 《Journal of agricultural and food chemistry》2007,55(8):2892-2900

Colorectal tumor risks could be reduced by polyphenol-rich diets that inhibit cell growth. Here, apple polyphenols were studied for effects on the survival of colon adenoma (LT97) and carcinoma-derived (HT29) cell lines. Three apple extracts (AEs) from harvest years 2002-2004 were isolated (AE02, AE03, and AE04) and fermented in vitro with human fecal flora. Extracts and fermentation products were analyzed for polyphenols with HPLC. The cells were treated with AEs (0-850 microg/mL) or fermented AEs (F-AEs, 0-9%), and survival was measured by DNA staining. All AEs contained high amounts of polyphenols (311-534 mg/g) and reduced cell survival (in LT97 > HT29). AE03 was most potent, possibly because it contained more quercetin compounds. Fermentation of AEs resulted in an increase of short chain fatty acids, and polyphenols were degraded. The F-AEs were approximately 3-fold less bioactive than the corresponding AEs, pointing to a loss of chemoprotective properties through fermentation.  相似文献   

Bacterial taxa that limit sulfur flux from the ocean     

Howard EC  Henriksen JR  Buchan A  Reisch CR  Bürgmann H  Welsh R  Ye W  González JM  Mace K  Joye SB  Kiene RP  Whitman WB  Moran MA 《Science (New York, N.Y.)》2006,314(5799):649-652

Flux of dimethylsulfide (DMS) from ocean surface waters is the predominant natural source of sulfur to the atmosphere and influences climate by aerosol formation. Marine bacterioplankton regulate sulfur flux by converting the precursor dimethylsulfoniopropionate (DMSP) either to DMS or to sulfur compounds that are not climatically active. Through the discovery of a glycine cleavage T-family protein with DMSP methyltransferase activity, marine bacterioplankton in the Roseobacter and SAR11 taxa were identified as primary mediators of DMSP demethylation to methylmercaptopropionate. One-third of surface ocean bacteria harbor a DMSP demethylase homolog and thereby route a substantial fraction of global marine primary production away from DMS formation and into the marine microbial food web.  相似文献   

Coherent response of a group of plantation-grown Scots pine trees to wind loading     

Dirk Schindler  Hannes Fugmann  Jochen Schönborn  Helmut Mayer 《European Journal of Forest Research》2012,131(1):191-202

Wind-induced motion of 29 neighbouring trees growing in a Scots pine plantation was measured over the period 14 March to 24 March 2008. The bi-orthogonal decomposition (BOD) of the complex tree motion field into a limited number of spatio-temporal modes provided the basis for the analysis of the response behaviour to wind excitation of the group of sample trees. It is shown that the first BOD-mode was the most energetic and differed from all other BOD-modes. The BOD-results as well as the results from wavelet analysis of the temporal eigenvectors of the BOD-modes demonstrate that two concomitant low-frequency components in the streamwise wind velocity component stimulated coherent response of the sample trees at the tree group level. However, in the range of the wind speed measured close to the top of the Scots pine forest canopy (hourly mean wind speed values lower than 6 m s⁻¹), the wind loads associated with these low-frequency airflow structures were too low to harmonise the motion of the sample trees completely. It is shown that instantaneous single tree responses to wind excitation were highly irregular in magnitude and direction. Results from Fourier and wavelet analysis demonstrate that sway in the first mode dominated the wind-induced sway behaviour at the tree level.  相似文献   

Recovery of Fascioloides magna (Digenea) population in spite of treatment programme? Screening of Galba truncatula (Gastropoda, Lymnaeidae) from Lower Austria     

Haider M  Hörweg C  Liesinger K  Sattmann H  Walochnik J 《Veterinary parasitology》2012,187(3-4):445-451

During the past decade, Fascioloides magna, the large American liver fluke, has spread within free-living deer in wetlands of the Danube in Lower Austria. The aim of this study was to determine the current infection rates with F. magna and other digenean parasites in the intermediate host snail Galba truncatula from risk areas in Lower Austria. A total of 3444 G. truncatula were collected and examined microscopically for the presence of digenean trematodes. A set of randomly selected snails and isolated trematode stages were also investigated molecular biologically by PCR and sequencing. Digenean parasites were detected with a prevalence of 2.41% (1.83% Paramphistomoidea; 0.46% Echinostomatoidea; 0.09% Strigeida; 0.06% Plagiorchiida). F. magna was found with an overall prevalence of 0.23%, which may indicate a recovery of the parasite population in spite of an ongoing triclabendazole treatment programme. Moreover, high risk areas and a seasonality of infections were observed.  相似文献   

Ostrich--a new avian host of Riemerella columbina     

Bocklisch H  Hühn F  Herold W  Tomaso H  Diller R  Hotzel H 《Veterinary microbiology》2012,154(3-4):429-431

  相似文献   

Perfluorooctanoate (PFO) in Forest Soils near a Fluoropolymer Manufacturing Facility     

Edzard Hangen  Andreas Klemm  Helmut Kronawitter  Alfred Schubert 《Water, air, and soil pollution》2010,212(1-4):491-499

After elevated concentrations of perfluorooctanoate (PFO) were found in river and groundwater in the vicinity of a fluoropolymer manufacturing facility, numerous soils at adjacent sites were sampled in 2007. Within a 5-km northeast-oriented sector around a probable point source, 20 forest sites were investigated and compared to deposition and groundwater data. PFO concentrations up to 600 µg/kg were detected in the soils, and PFO concentrations typically decreased toward deeper soil depths. In mixed or deciduous forests, maximum concentrations of PFO occurred in the topsoil, pointing to the favorable decomposition and incorporation of deciduous litter. PFO concentrations of the organic layer over the 20 sampling sites were interpolated using ordinary kriging. Highest PFO content in the organic layer was located about 500 m away from the point source in the regional wind direction, decreasing asymptotically outwards. Long-term monitoring data pointed to an accumulation of PFO over time in the organic layer. The data suggest that PFO might be released in the course of litter decomposition and transported toward deeper soil regions only gradually. The soils’ PFO concentrations reflect the deposition data. The transport link toward groundwater is currently established in lysimeter studies.  相似文献   

Urine excretion of pentachlorophenol (PCP) in occupational exposure     

Franco Barbieri  Claudio Colosio  Helmut Schlitt  Marco Maroni 《Pest management science》1995,43(4):259-262

The pharmacokinetics of pentachlorophenol (PCP) excretion in urine was examined in four workers exposed to the biocide in the tannery and wood industries. PCP concentration in urine was significantly higher in morning samples than in afternoon or evening samples. This excretion pattern was observed during an exposure of several shifts and following a four-week holiday period. The estimated half-life for PCP urine excretion was 10 days. Biological monitoring of occupational exposure to PCP should be carried out by measuring the concentration of the compound in urine collected in the morning or before the workshift.  相似文献   

The dual role of wild phages for horizontal gene transfer among Salmonella strains     

Rabsch W  Mirold S  Hardt WD  Tschäpe H 《Berliner und Münchener tier?rztliche Wochenschrift》2002,115(9-10):355-359

Salmonella bacteriophages seem to mediate horizontal transfer of virulence functions among Salmonella strains in two different ways: by general transduction and also by lysogenic conversion. The majority of wild phages isolated from Salmonella strains belong to the P22 like phages and were able to transduce. Our data show that the lysogenic conversion is generally accompanied by changes in the susceptibility to the typing phages used for epidemiological purposes. Similar phage type conversions to S. Typhimurium DT104 could be detected upon lysogenization with two other S. Typhimurium strains. For some S. Typhimurium strains the typical phage pattern is actually associated with alterations of virulence characteristics. For example, all tested wild type isolates of phage types DT49 and DT204 were found to be SopE phi-lysogens. The Anderson typing phages interfere with the prophages and/or cryptic phages and so the complex genetic short-term evolution can be demonstrated in the lab. This is one reason for the successful application of phage typing in Salmonella epidemiology since the 50s.  相似文献   

Untersuchungen zum Artenspektrum von Fusarium-Pilzen im Erntegut von Getreide im Land Brandenburg     

Cornelia Müller  Helmut Bröther 《Gesunde Pflanzen》2002,54(2):33-37

  相似文献