Variation in Heterobasidion annosum detected by Random Amplified Polymorphic DNAs

The production of Random Amplified Polymorphic DNAs (RAPDs) by Polymerase Chain Reaction (PCR) was used to detect variation in the isolates of Heterobasidion annosum with various geographical origins. Specific RAPD products were detected for each of the intersterility groups: the European S, F, P and the North American S group. There was considerably more polymorphism found among European S than P isolates. The analysis of RAPDs was shown to be a simple and a fast way to generate DNA markers specific to the previously established intersterility groups and thus useful for diagnostic purposes.     

The impact of small-scale design interventions on the behaviour patterns of the users of an urban wasteland

Urban derelict space can form a valuable complementary element to the formal green spaces of a city: wastelands are often biologically diverse and their unregulated status can provoke innovative spatial activities by a wide range of users. Using the case of an urban brownfield in Tallinn, Estonia, this paper examines how such a space is used and evaluates the magnitude of the impact of minor design interventions – so-called urban acupuncture – on the activities carried out by the users. The study used field observations and behaviour mapping to compare the spatial pattern of the users before and after small design interventions. Although there was widespread use beforehand there was both an increase in use and a different pattern afterwards, which was clearly detectable from the composite behaviour maps of both arrangements, where users follow the properties of the particular environment. The small improvements tested showed the largest effect on the female and the older user groups, raising the number of overall visits and increasing the occurrence of active behaviour almost five times. The research demonstrates that small, inexpensive and possibly temporary interventions can have a major positive effect.     

Genetic basis of penicillin resistance of S. aureus isolated in bovine mastitis

Background

The blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids. The aim of this study was to investigate the genetic relationships and to determine the location of the blaZ gene in S. aureus isolated in bovine mastitis in Finland and Sweden.

Methods

Seventy-eight β-lactamase positive S. aureus isolates from bovine mastitis (34 from Finland and 44 from Sweden) were included in the study. The localization of blaZ gene was determined by Southern blotting. The blaZ genes of the isolates were sequenced and the sequences were translated to beta-lactamase proteins and further grouped as different protein signatures. The isolates and, as control, 33 Swedish and 36 Finnish beta-lactamase negative isolates were typed with pulsed-field gel electrophoresis (PFGE).

Results

In 26 out of 34 Finnish isolates (76.5%) and in 25 out of 44 Swedish isolates (56.8%) the blaZ gene was localized on a plasmid. Six different protein signatures were found. One signature was found only in four Swedish isolates, but all other signatures were found both in Finnish and Swedish isolates. The PFGE results revealed a diversity of S. aureus clones. The protein signatures were not clearly associated with certain pulsotypes.

Conclusions

The plasmid location of the blaZ gene was not statistically significantly more common in Finland than in Sweden, and hence does not explain the higher proportion of penicillin-resistant isolates of S. aureus causing bovine mastitis in Finland compared to Sweden.     

The first detection of influenza in the Finnish pig population: a retrospective study

Background

Swine influenza is an infectious acute respiratory disease of pigs caused by influenza A virus. We investigated the time of entry of swine influenza into the Finnish pig population. We also describe the molecular detection of two types of influenza A (H1N1) viruses in porcine samples submitted in 2009 and 2010.This retrospective study was based on three categories of samples: blood samples collected for disease monitoring from pigs at major slaughterhouses from 2007 to 2009; blood samples from pigs in farms with a special health status taken in 2008 and 2009; and diagnostic blood samples from pigs in farms with clinical signs of respiratory disease in 2008 and 2009. The blood samples were tested for influenza A antibodies with an antibody ELISA. Positive samples were further analyzed for H1N1, H3N2, and H1N2 antibodies with a hemagglutination inhibition test. Diagnostic samples for virus detection were subjected to influenza A M-gene-specific real-time RT-PCR and to pandemic influenza A H1N1-specific real-time RT-PCR. Positive samples were further analyzed with RT-PCRs designed for this purpose, and the PCR products were sequenced and sequences analyzed phylogenetically.

Results

In the blood samples from pigs in special health class farms producing replacement animals and in diagnostic blood samples, the first serologically positive samples originated from the period July–August 2008. In samples collected for disease monitoring, < 0.1%, 0% and 16% were positive for antibodies against influenza A H1N1 in the HI test in 2007, 2008, and 2009, respectively. Swine influenza A virus of avian-like H1N1 was first detected in diagnostic samples in February 2009. In 2009 and 2010, the avian-like H1N1 virus was detected on 12 and two farms, respectively. The pandemic H1N1 virus (A(H1N1)pdm09) was detected on one pig farm in 2009 and on two farms in 2010.

Conclusions

Based on our study, swine influenza of avian-like H1N1 virus was introduced into the Finnish pig population in 2008 and A(H1N1)pdm09 virus in 2009. The source of avian-like H1N1 infection could not be determined. Cases of pandemic H1N1 in pigs coincided with the period when the A(H1N1)pdm09 virus was spread in humans in Finland.     

The role of oxylipins and antioxidants on off-flavor precursor formation during potato flake processing

The impact of processing on nonenzymatic antioxidant degradation and lipid oxidation leading to off-flavor development in potato flakes during storage was investigated. Lipoxygenase activity measurements in parallel with the analysis of lipid oxidation products (oxylipins) profiles using HPLC showed that the processing conditions used inhibited efficiently enzymatic lipid oxidation. However, nonenzymatic lipid oxidation products were found throughout processing and in fresh potato flakes. Furthermore, these autoxidative processes cannot be inactivated by the main endogenous nonenzymatic antioxidants in potato tubers (ascorbic acid, phenolic compounds and carotenoids), as these antioxidants are degraded during processing. Indeed, leaching and thermal treatments taking place during processing lead to a decrease of about 95%, 82% and 27% in the content of ascorbic acid, phenolic compounds and carotenoids, respectively. Therefore, storage is a critical step to prevent off-flavor development in potato flakes. Specific attention has thus to be paid on the use of efficient exogenous antioxidants as well as on storage conditions.     

Factors causing temporal and spatial variation in heterotrophic and rhizospheric components of soil respiration in afforested organic soil croplands in Finland

Partitioning soil respiration (SR) into its components, heterotrophic and rhizospheric respiration, is an important step for understanding and modelling carbon (C) cycling in organic soils. However, no partitioning studies on afforested organic soil croplands exist. We separated soil respiration originating from the decomposition of peat (SR_P), and aboveground litter (SR_L) and root respiration (SR_R) in six afforested organic soil croplands in Finland with varying tree species and stand ages using the trenching method. Across the sites temporal variation in SR was primarily related to changes in soil surface temperature (?5 cm), which explained 71–96% of variation in SR rates. Decomposition of peat and litter was not related to changes in water table level, whereas a minor increase in root respiration was observed with the increase in water table depth. Temperature sensitivity of SR varied between the different respiration components: SR_P was less sensitive to changes in soil surface temperature than SR_L or SR_R. Factors explaining spatial variation in SR differed between different respiration components. Annual SR_P correlated positively with peat ash content while that of SR_L was found to correlate positively with the amount of litter on the forest floor, separately for each tree species. Root respiration correlated positively with the biomass of ground vegetation. From the total soil respiration peat decomposition comprised a major share of 42%; the proportion of autotrophic respiration being 41% and aboveground litter 17%. Afforestation lowered peat decomposition rates. Nevertheless the effect of agricultural history can be seen in peat properties for decades and due to high peat decomposition rates these soils still loose carbon to the atmosphere.     

Risk factors for post-weaning diarrhoea on piglet producing farms in Finland

Background

Post-weaning diarrhoea (PWD) is a significant gastrointestinal disease in pigs. It is considered a multifactorial disease associated with proliferation of enterotoxigenic Escherichia coli in the intestinal tract of affected pigs. The aim of this study was to analyse risk factors related to the occurrence of PWD on Finnish piglet producing farms.

Methods

The data of a follow-up study of 73 conventional piglet producing farms was used in the case-control study. The selection of the 41 PWD case and 28 control farms was based on the use of antimicrobials for treating diarrhoea in weaned pigs and the answers related to the occurrence of diarrhoea after weaning in the questionnaire. Four intermediate farms were excluded from the statistical analysis.Altogether 39 factors related to herd characteristics, weaner pig management and pig health were studied. The median number of sows was 59.0 (IQR = 44.0; 74.5) and 52.5 (IQR = 36.8; 61.5) on the case and the control farms, respectively.The significances of the univariable associations between the explanatory variables and the outcome variable were tested, and in the multivariate analysis quasibinomial generalized linear models were applied.

Results

An increased risk of PWD was associated with the regimen of twice a day feeding and feed restriction after weaning (P = 0.02; compared to feeding three or more meals a day or the use of ad libitum feeding) and with a higher number of sows on the farm (P = 0.02; risk increasing with increasing number of sows). Automatic temperature control was associated with a decreased risk of PWD (P = 0.03; compared to manual temperature control).

Conclusion

Twice a day feeding of newly-weaned pigs should be avoided if the amount of feed given is restricted. Variation in ambient temperature should be minimized in housing of newly-weaned pigs and this can be achieved by using automatic temperature control. With increasing number of sows in the herds the risk of PWD increases and more attention should be paid to prevention of post-weaning diarrhoea.     

Spatial eco-evolutionary feedback in plant-pathogen interactions

In recent years the potential for evolutionary change to drive ecological dynamics, and vice versa, has been widely recognized. However, the convincing examples of eco-evolutionary dynamics mainly stem from highly artificial experimental systems, with conspicuously few examples contributed by field systems. While rarely considered in the eco-evolutionary literature, the gene-for-gene hypothesis inherently recognizes the tight link between evolutionary and ecological dynamics. The boom-and-bust dynamics of some agricultural pathogens are an extreme demonstration of this. In this perspective, we place plant-pathogen systems in a spatial eco-evolutionary framework, which recognizes that ecology and evolution are tightly linked, take place at the same time scale and are strongly influenced by spatial structure. Specifically, we: i) exemplify how the ecological process of dispersal modifies rapid local coevolutionary dynamics and thereby shapes spatial variation in resistance, infectivity, and local adaptation; and ii) illustrate how the outcome of coevolution (spatial distribution in resistance, infectivity and local adaptation) drives ecological metapopulation processes. Overall, we conclude that both agricultural and wild pathosystems provide a unique illustration of the high relevance of spatial eco-evolutionary feedback in understanding species interactions.