Development and evaluation of a mixed long-chain lipopolysaccharide based ELISA for serological surveillance of infection with Actinobacillus pleuropneumoniae serotypes 2, 6 and 12 in pig herds

The objective was to develop an enzyme-linked immunosorbent assay (ELISA) for simultaneous detection of antibodies against Actinobacillus pleuropneumoniae (Ap) serotypes 2, 6 and 12. The assay was designated MIX-ELISA. Lipopolysaccharide (LPS) from Ap serotypes 2, 6 and 12 was purified using hot phenol-water extraction followed by fractionation by size-exclusion chromatography. A mixture of fractions containing molecules with molecular weight above 50 kDa from all three serotypes was used as antigen. The MIX-ELISA was evaluated with sera from pigs experimentally infected with the serotypes 1, 2, 5b, 6, 7, 8, 10 and 12 of Ap biotype 1. In addition to reaction with sera from pigs inoculated with Ap serotypes 2, 6 and 12, reaction was observed with sera from pigs inoculated with serotype 8. Furthermore, the sensitivity and specificity of the test on a herd level were evaluated with sera from herds naturally infected with serotypes 2, 6 or 12 and with sera from herds free of infection with any Ap serotype of biotype 1. The ELISA showed a high herd sensitivity (0.98; 95% confidence interval: 0.89-1.00) and specificity (0.95; 0.88-0.99). The high diagnostic sensitivity and specificity of the assay indicate that screening of herds for Ap infection can be performed using this ELISA. Efficient serological surveillance can be achieved by using such mixed antigen ELISAs coated with size-selected LPS-antigens from the most prevalent serotypes.     

Environmental justice and park quality in an intermountain west gateway community: assessing the spatial autocorrelation

Context

Research on environmental justice issues, particularly unequal park distribution and quality, has found that communities’ minority density and socioeconomic status (SES) are often correlated with disparate park qualities. However, most studies of spatial relationships between park quality and socioeconomic factors employ simple statistical analyses, which do not account for potential spatial autocorrelations and their effects on validity.

Objectives

This study determines whether the distribution of park quality is spatially autocorrelated and assesses the associations among multiple indicators of environmental justice and both separate park features and overall park quality.

Methods

This study evaluates spatial relationships between park quality and multiple environmental justice indicators in Cache County, Utah following the spatial regression process conducted in R programming language. Both overall park quality and separate feature qualities were audited by the PARK (Parks, Activity, and Recreation among Kids) tool. Environmental justice indicators included minority density, poverty, unemployment, low-education, renter rate, and yard size.

Results

Results illustrate a spatial autocorrelation existing in park quality distribution, detecting the dependence of the variable for quantitative research. They also show significant correlations between park quality and environmental justice indicators.

Conclusions

The study’s spatial regression model is a model for analyzing the spatial data and avoids the autocorrelation which is overlooked by the normal statistical approaches. Also, variances of park quality can be accounted for by different environmental justice indicators, such as minority density, poverty, and yard size. This disclosure of disparate public resource quality treatment among different groups of individuals could inspire policy makers and city planners to correct these disparities.

     

Comparing biophysical forest characteristics estimated from photogrammetric matching of aerial images and airborne laser scanning data

Recent development in aerial digital cameras and software facilitate the photogrammetric point cloud as a new data source in forest management planning. A total of 151 field training plots were distributed systematically within three predefined strata in a 852.6 ha study area located in the boreal forest in southeastern Norway. Stratum-specific regression models were fitted for six studied biophysical forest characteristics. The explanatory variables were various canopy height and canopy density metrics derived by means of photogrammetric matching of aerial images and small-footprint laser scanning. The ground sampling distance was 17 cm for the images and the airborne laser scanning (ALS) pulse density was 7.4 points m^–2. Resampled images were assessed to mimic acquisitions at higher flying altitudes. The digital terrain model derived from the ALS data was used to represent the ground surface. The results were evaluated using 63 independent test stands. When estimating height in young forest and mature forest on poor sites, the root mean square error (RMSE) values were slightly better using data from image matching compared to ALS. However, for all other combinations of biophysical forest characteristics and strata, better results were obtained using ALS data. In general, the best results were found using the highest image resolution.     

Implementing urban greening aid projects – The case of St. Petersburg, Russia

Recent years have seen the introduction of the concept of urban greening, defined as embracing the planning and management of all urban vegetation to create or add values to the local community. Green-space development has become recognised by international agencies and donors as important tool in improving the quality of urban livelihoods and urban environment. This paper evaluates an example of an urban greening aid project, carried out by Danish and Russian partners in the city of St. Petersburg, Russia. The project aimed to contribute to conservation and development of the cultural–historical, social and ecological values of St. Petersburg's urban green areas by implementing a structured, socially inclusive, well-informed planning and management approach. The project had three main components: (1) the development of a GIS-based information system to assist green-space planning and management; (2) on-site improvements in selected green areas and (3) awareness raising and public involvement activities. Ex post evaluation of the project showed that in spite of the limits of time and resources, important results were achieved. A more strategic approach to urban green-space planning and management, as promoted by urban greening, was adapted by some of the Russian project partners. Achievements also included notable physical improvements to one park. But the main project impacts were improved communication and collaboration between the local park department and local academia, as well as expertise developed in running a complex urban greening project. The project failed, however, in its public involvement ambitions.Moreover, the project should have facilitated discussion on some of the current premises of urban green-space planning and management in St. Petersburg, which insufficiently consider changing values and public preferences related to green spaces.     

Effect of freezing and thawing on microbial activity and glyphosate degradation in two Norwegian soils

Little research has been done on pesticide dissipation in cold climates and there is a need to focus on the influence of climate on pesticide degradation in soil. Glyphosate, N-(phosphonomethyl)glycine, is a herbicide frequently used for controlling perennial weeds through application after harvest and was used as a model compound for this study. The effect of freeze-thaw activity on the availability of glyphosate in soil, and consequently its mineralization by soil microorganisms, was studied through laboratory incubations of repacked soil cores treated with 14C-labelled glyphosate and subjected to different freeze-thaw treatments. Winter simulation regimes applied were constant thaw (+5 degrees C), constant freezing (-5 degrees C), unstable conditions with short fluctuations (24 h of -5 degrees C followed by 24 h of +5 degrees C), and long duration fluctuations (3 weeks of -5 degrees C followed by 3 weeks of +5 degrees C). Distribution of 14C-glyphosate was followed during the incubation through measurements of the mineralized fraction (14CO2), soil water fraction, KOH extractable fraction, and non-extractable fraction. Microbial parameters used to characterize the soils were estimates of size of microbial biomass, overall microbial activity and microbial diversity. The constant freezing treatment exhibited the lowest amount of glyphosate mineralization. The constant thawed treatment and the treatments with fluctuating temperature exhibited significantly increased mineralization. These results were in accordance with the observed concentration of glyphosate in soil water; the higher the activity, the lower the concentration. The amount of glyphosate extractable with KOH and the resulting non-extractable fraction, however, were not significantly affected by soil type or temperature regime. The glyphosate mineralization pattern was comparable with the overall microbial activity in the soils. Observed different levels of diversity might explain some of the difference in total glyphosate mineralization between soils.     

Induction of Beet-Cyst Nematode Suppressiveness by the Fungi Dactylella oviparasitica and Fusarium oxysporum in Field Microplots

ABSTRACT The ability of Dactylella oviparasitica and Fusarium oxysporum to suppress Heterodera schachtii numbers was examined in field microplots. Fungi were individually added to fumigated field soil that was seeded with sugar beet. Four weeks later, soils were infested with H. schachtii second-stage juveniles (J2). At two harvests, 11 weeks and 19 weeks (1,469 and 2,547 degree days (base 8 degrees C), respectively) after nematode-infestation, H. schachtii cyst and egg numbers were assessed. At both time points, D. oviparasitica reduced H. schachtii population densities to those in the naturally suppressive soil, even when additional H. schachtii J2 were added to the microplots after the first harvest. Although F. oxy-sporum did not alter H. schachtii population densities after 11 weeks, significant reductions were detected after 19 weeks. The sustainability of the H. schachtii suppressiveness created by single applications of the fungi at the beginning of the microplot trials was further examined in a greenhouse study. Soil collected at the completion of the microplot trials was potted and seeded with sugar beet. Four weeks later, each pot was infested with H. schachtii J2. Approximately 16 weeks (1,389 degree days) after seeding, the D. oviparasitica-amended soil produced greater fresh root weights and considerably smaller nematode population densities than the nonamended control.