Public health. Monitoring EU emerging infectious disease risk due to climate change     

Lindgren E  Andersson Y  Suk JE  Sudre B  Semenza JC 《Science (New York, N.Y.)》2012,336(6080):418-419

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Clear-cutting affects the ammonia-oxidising community differently in limed and non-limed coniferous forest soils     

Jenny?S.?K.?B?ckmanEmail author  ?sa?Kasimir?Klemedtsson  Leif?Klemedtsson  Per-Eric?Lindgren 《Biology and Fertility of Soils》2004,40(4):260-267

The effects of clear-cutting on the ammonia-oxidising bacterial community were studied in the soil of limed and non-limed spruce forest plots located in the central part of southern Sweden. The communities were studied using denaturing gradient gel electrophoresis (DGGE) profiling after polymerase chain reaction (PCR) amplification from total DNA with primers reported to be specific for -subgroup ammonia-oxidising bacteria. The bands on the DGGE were sequenced and each unique sequence was interpreted as representing one ammonia-oxidising population. The relative abundance of each population was determined by measuring the fluorescence of the respective DGGE bands. In both limed and non-limed soil, the same two Nitrosospira populations were found, one belonging to cluster 2 (NScl2) and one to cluster 4 (NScl4). However, while NScl4 first appeared a year after the clear-cutting in the non-limed plot, it was present both before and after the cutting in the limed plot. Irrespective of previous liming, clear-cutting caused a shift in the ammonia-oxidiser community, from dominance by the NScl2 population to a community with approximately equal relative abundance of NScl2 and NScl4. In both plots the total size of the community increased after clear-cutting (based on increased DGGE band intensity), most likely due to increased NH₄⁺ availability, but the growth response was faster in the limed plot. Hence, the prior liming increased the responsiveness of the ammonia-oxidisers to the changes caused by cutting. This is the first study to report the effects of clear-cutting on the ammonia-oxidising community, and the results show a clear correlation between increased potential nitrification and a shift in the ammonia-oxidiser community.  相似文献   

Overland flow systems for treatment of landfill leachates—Potential nitrification and structure of the ammonia-oxidising bacterial community during a growing season     

Carina Sundberg  Jenny S. K. Stendahl  Per-Eric Lindgren 《Soil biology & biochemistry》2007,39(1):127-138

Overland flow systems are useful for treating landfill leachates, because they provide favourable conditions for nitrification and they are easy to maintain. However, little is known about the microbial communities in such systems or the nitrification capacity of those microorganisms. In this study, seasonal variations in potential nitrification and in community composition of nitrifying bacteria were investigated in two overland flow areas receiving leachate from landfills at Korslöt and Hagby, Sweden. Samples were collected in the settling ponds sediment and at two depths in the overland flow areas (the macrophyte litter layer and the rhizosphere) in May, August and November 2003. A short-term incubation method was used to measure potential oxidation of ammonia and nitrite (designated PAO and PNO). The ammonia-oxidising bacterial (AOB) community was investigated using a 16S rRNA gene approach that included PCR amplification and analysis of PCR products by denaturing gradient gel electrophoresis (DGGE), followed by nucleotide sequencing and phylogenetic analysis.PAO was determined in the range 5-2700 (NO₂⁻+NO₃⁻)-N g⁻¹ dw d⁻¹ and PNO in the range 60-2000 μg NO₂⁻-N g⁻¹ dw d⁻¹. At Korslöt, PAO and PNO showed similar temporal variation in the different ecosystems, whereas no such relationship was noticed at Hagby. Considering both sites, there was no obvious change in the composition of the AOB community over the growing season. However, the composition did differ between the ecosystems: Nitrosomonas-like sequences were more common in the ponds, and in the litter layers they were found as often as Nitrosospira-like sequences, whereas Nitrosospira-like sequences were more common in the rhizospheres. Altogether, we found nine different AOB sequences, five Nitrosomonas-like and four Nitrosospira-like, which belonged to clusters 0, 2, 3b, 6a, 6b and 7. There was no apparent relationship between the number of AOB populations and the PAO in different soil layers and sediments.  相似文献   

Technical and Environmental Functioning of Detention Ponds for the Treatment of Highway and Road Runoff   总被引：1，自引：0，他引：1  

Peter Starzec  BO B. Lind  Anders Lanngren  Åsa Lindgren  Torbjörn Svenson 《Water, air, and soil pollution》2005,163(1-4):153-167

Based on an inventory of more than 200 facilities for the treatment of road runoff water in Sweden, 26 representative stormwater ponds were studied with regard to technical function, maintenance and metal accumulation. Sediment accumulation and metal content in the pond sediment was studied in relation to concentration in the runoff water, spatial variation and pond geometry. It emerged that the pollution retention capacity was not optimal for many of the ponds. The observed sediment thickness was low reflecting turbulent conditions and that much of the pollutants are transported through the ponds. Statistical tests performed on 15 ponds showed a significant relationship between metal content in sediment and pond size while pond shape was found to have no effect on accumulation rate. There is still significant potential for the development of the design and technical function of the ponds, e.g. design elements such as pre-settlement trench and elements for enhancing high hydraulic efficiency. Disturbance of the technical function, in terms of clogging of pipes, erosion, flooding etc. was reviewed for three of the ponds, however only 50% of the ponds did show some form of documented maintenance-program. This generates an obvious threat to the effective long-term function of these ponds.  相似文献   

A major QTL for common bacterial blight resistance derives from the common bean great northern landrace cultivar Montana No.5     

Phillip N. Miklas  Dermot P. Coyne  Kenneth F. Grafton  Nedim Mutlu  Jim Reiser  Dale T. Lindgren  Shree P. Singh 《Euphytica》2003,131(1):137-146

Knowledge of the evolutionary origin and sources of pest resistance genes will facilitate gene deployment and development of crop cultivars with durable resistance. Our objective was to determine the source of common bacterial blight (CBB) resistance in the common bean Great Northern Nebraska #1 (GN#1) and GN#1 Selection 27 (GN#1 Sel 27). Several great northern cultivars including GN#1, GN#1 Sel 27, and Montana No.5 (the female parent of the common x tepary bean interspecific population from which GN #1 and GN # 1 Sel 27 were derived) and known susceptible checks were evaluated for CBB reaction in field and greenhouse environments. These genotypes and CBB resistant and susceptible tepary bean including Tepary #4, the male parent and presumed contributor of CBB resistance toGN#1 and GN#1 Sel 27, were assayed for presence or absence of three SCAR markers tightly linked with independent QTLs conditioning CBB resistance. The parents and F₂ of Montana No. 5/GN #1 Sel 27 and Montana No.5/Othello(CBB susceptible) were screened for CBB reaction and SCAR markers. CBB resistance in Montana No.5 was comparable to that of GN#1 and GN#1 Sel27. The SAP6 SCAR marker present in GN#1 and GN#1 Sel 27 was also present in Montana No.5, and it co-segregated (R ² =35%) with the CBB resistance in the Montana No.5/Othello F₂ population. Although a few CBB resistant and susceptible transgressive segregants were found in the F₂ of MontanaNo.5/GN #1 Sel 27 and later confirmed by F₃ progeny tests, SAP6 SCAR marker was present in all progenies. None of the tepary bean specific CBB resistance-linked SCAR markers were present in GN#1, GN#1 Sel 27, or Montana No.5. A cluster analysis of 169 polymorphic PCR-based markers across three common bean and Tepary #4 indicated that GN#1, GN#1 Sel 27, and Montana No.5 were closely related, and not related at all with Tepary #4.Thus, these results clearly indicate Montana No.5, not Tepary #4, as the source of CBB resistance in GN#1 and GN#1 Sel 27. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Cold acclimation of Pinus contorta and Pinus sylvestris assessed by chlorophyll fluorescence     

Lindgren K  Hällgren JE 《Tree physiology》1993,13(1):97-106

Needle samples of six provenances each of lodgepole pine (Pinus contorta Dougl. var. latifolia) and Scots pine (Pinus sylvestris L.), originating from latitudes 55 to 68 degrees N in western Canada and northern Sweden, were collected during the autumn and subjected to freezing temperatures in the range of -8 to -29 degrees C on three occasions in September and October. Needle injury was assessed by two different methods: visual assessment and chlorophyll a fluorescence. Chlorophyll a fluorescence data showed a highly significant correlation with the visual assessments of injury, indicating that the technique can be used as a simple, non-destructive and objective measure for rapid detection of freezing injury and for ranking of needle materials with respect to development of cold acclimation. The analyses showed that, during the autumn, lodgepole pine needles were more hardy and acclimated to low temperatures earlier than Scots pine needles.  相似文献   

Estimation of fertility variation in forest tree populations   总被引：2，自引：0，他引：2  

Kang  K.-S.; Bila  A.D.; Harju  A.M.; Lindgren  D. 《Forestry》2003,76(3):329-344

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Structural studies on the chemical bonds between lignins and carbohydrates in spruce wood   总被引：7，自引：0，他引：7  

Ö. Eriksson  D. A. I. Goring  B. O. Lindgren 《Wood Science and Technology》1980,14(4):267-279

Summary A lignin-carbohydrate material from black spruce (Picea mariana) was treated with a hemicellulase mixture. The carbohydrates in the remaining material were studied by the following methods. a) Treatment with 0.1 M NaOH in the presence of sodium borohydride followed by selective hydrolysis of the furanosidic bonds, b) Smith degradation (periodate oxidation followed by mild acid hydrolysis). The results obtained indicate that lignin is bound to all types of sugar units in the hemicelluloses. For arabino-4-O-methylglucuronoxylan, linkages to the side-chain units seem to dominate. The links to the 4-O-methylglucuronic acid units are ester bonds, probably benzyl ester bonds. Those to the other sugar units in the hemicelluloses are ether bonds, probably benzyl ether bonds. The results suggest, furthermore, that fractions of cellulose are linked to lignin.The authors are indebted to Dr. H. H. Brownell, Ottawa, Canada, for a gift of extracted black spruce wood meal, and to Professor Bengt Lindberg, Stockholm, Sweden, for the use of glc equipment in his laboratory  相似文献   

A model integrating seed source adaptation and seed use     

Lindgren  D.  Ying  C.C. 《New Forests》2000,20(1):87-104

A conceptual model that considers theperformance (adaptability) of a seed source (=anorigin) and the location or range of its deployment isdeveloped employing the Cauchy function. The modelassumes that there exists an optimal site type foreach provenance origin (genetic material), and thatloss in performance is a function of the distance (ameasure of increasing maladaptation) from the optimalsite. The model requires the estimate of threeparameters: a site requirement value that measuressite type in one dimension; a measure of optimalperformance; and a flexibility measure of the width ofseed source adaptability. The Cauchy function has aknown integral, thus the average adaptability over arange (a possible seed use zone) can be mathematicallyevaluated. The model was also extended to seed orchardcrops representing progeny of parents of variableorigins. Scots pine information in Sweden was used todemonstrate possible applications of the model.  相似文献   

Long-term responses of ecosystem components to stand thinning in young lodgepole pine forest: IV. Relative habitat use by mammalian herbivores     

Thomas P. Sullivan  Druscilla S. Sullivan  Pontus M.F. Lindgren  Douglas B. Ransome 《Forest Ecology and Management》2007,240(1-3):32-41

Pre-commercial thinning (PCT) is a silvicultural practice that can provide diverse understory and overstory vegetation conditions. We tested the hypothesis that relative habitat use by snowshoe hare (Lepus americanus), mule deer (Odocoileus hemionus), and moose (Alces alces) would increase in response to enhanced abundance of herbs and shrubs, and species diversity and structural diversity of conifers, in heavily thinned (≤1000 stems/ha) stands, at 12–15 years post-thinning. Replicate study areas were located near Penticton, Kamloops, and Prince George in south-central British Columbia, Canada. Each study area had three young pine stands thinned to densities of 500 stems/ha (low), 1000 stems/ha (medium), and 2000 stems/ha (high), with an unthinned young pine and old-growth pine stand for comparison.

Relative habitat use, based on counts of fecal pellets and pellet-groups, was similar among the five treatment stands for hares (P = 0.24), deer (P = 0.23), and moose (P = 0.16). However, low-density stands (500 stems/ha) had ca. 3–20 times as many deer pellet-groups, and ca. 2–4 times as many moose pellet-groups, than other stands. Low-density stands had significantly greater canopy openness, volume of shrubs <2 m, and horizontal hiding cover <1.6 m than other treatments. Relative habitat use by deer and moose was positively related to understory characteristics such as enhanced abundance of forage and security cover. These results support our hypothesis that deer and moose responded positively to enhanced volume of herbs and shrubs as well as to species diversity and structural diversity of conifers and overall vegetation in heavily thinned (≤1000 stems/ha) stands at 12–15 years post-thinning. Our results suggest that ungulate management would be enhanced if greater emphasis was placed on forage enhancement throughout the year, which differs from current management recommendations which tend to focus on winter range and snow-interception cover.  相似文献