Pleuritis in slaughter pigs: Relations between lung lesions and bacteriology in 10 herds with high pleuritis

Pleuritis in slaughter pigs has increased in recent years in the Netherlands. The aim of the present study was to determine what respiratory pathogens were involved in pleuritis.In total, lungs of 968 slaughter pigs from 10 herds with high prevalence of pleuritis were morphologically examined for size, location, and type of lesions. Moreover, histology and bacteriology were performed.Examination of gross lung lesions showed 45% pleuritis, 14% pleuropneumonia and 38% catarrhal pneumonia. Peribronchiolar cuffing was found in 61 of 142 samples. Actinobacillus pleuropneumoniae was cultured from 22 lung samples from four herds. Pasteurella multocida was cultured from 55 lung samples in eight herds. No specific pattern with respect to the causal pathogens was found.In conclusion, no single infectious cause of pleuritis was found. A variety of infectious agents combined with environmental factors should be considered as a cause of pleuritis.     

Addressing the interplay of poverty and the ecology of landscapes: a Grand Challenge Topic for landscape ecologists?

We argue for the landscape ecology community to adopt the study of poverty and the ecology of landscapes as a Grand Challenge Topic. We present five areas of possible research foci that we believe that landscape ecologists can join with other social and environmental scientists to increase scientific understanding of this pressing issue: (1) scale and poverty; (2) landscape structure and human well-being; (3) social and ecological processes linked to spatial patterns in landscapes; (4) conservation and poverty, and (5) applying the landscape ecologist’s toolkit. A brief set of recommendations for landscape ecologists is also presented. These include the need to utilize broad frameworks that integrate social and ecological variables, build capacity to do this kind of work through the development of strong collaborations of researchers in developed and developing countries, create databases in international locations where extreme poverty exists, and create a new generation of researchers capable of addressing this pressing social and environmental issue.     

Effect of land use types on decomposition of 14C-labelled maize residue (Zea mays L.)

The effect of three land use types on decomposition of ¹⁴C-labelled maize (Zea mays L.) residues and soil organic matter were investigated under laboratory conditions. Samples of three Dystric Cambisols under plow tillage (PT), reduced tillage (RT) and grassland (GL) collected from the upper 5 cm of the soil profile were incubated for 159 days at 20 °C with or without ¹⁴C-labelled maize residue. After 7 days cumulative CO₂ production was highest in GL and lowest in PT, reflecting differences in soil organic C (SOC) concentration among the three land use types and indicating that mineralized C is a sensitive indicator of the effects of land use regime on SOC. ¹⁴CO₂ efflux from maize residue decomposition was higher in GL than in PT, possibly due to higher SOC and microbial biomass C (MBC) in GL than in PT. ¹⁴CO₂ efflux dynamics from RT soil were different from those of PT and GL. RT had the lowest ¹⁴CO₂ efflux from days 2 to 14 and the highest from days 28 to 159. The lowest MBC in RT explained the delayed decomposition of residues at the beginning. A double exponential model gave a good fit to the mineralization of SOC and residue-¹⁴C (R² > 0.99) and allowed estimation of decomposition rates as dependent on land use. Land use affected the decomposition of labile fractions of SOC and of maize residue, but had no effect on the decomposition of recalcitrant fractions. We conclude that land use affected the decomposition dynamics within the first 1.5 months mainly because of differences in soil microbial biomass but had low effect on cumulative decomposition of maize residues within 5 months.     

Identification and characterization of international Fusarium head blight screening nurseries of wheat at CIMMYT, Mexico

Fusarium head blight (FHB) is a major threat to wheat production globally, causing not only yield losses but also food and feed contamination. FHB research began at the International Maize and Wheat Improvement Center (CIMMYT) in the early 1980’s, and since then, large-scale FHB screening has been conducted to identify and incorporate new resistance genes into elite CIMMYT germplasm. Promising lines with good FHB resistance were regularly compiled as a Fusarium Head Blight Screening Nursery (FHBSN) and distributed worldwide. The first FHBSN was assembled in 1985, and the most recent two were the 13th and 14th FHBSN that were released in 2011 and 2012, respectively. Candidate lines for a FHBSN came mainly from different CIMMYT wheat breeding programs and were tested for three consecutive years before being included in an FHBSN. FHBSN screening was conducted under strictly standardized field conditions at El Batán, where CIMMYT headquarters is located, using artificial inoculation of F. graminearum strains, whose aggressiveness and DON chemotypes had been previously identified. FHB index was scored at 31 days after inoculation for all lines and DON concentration was measured only for elite lines in their 2nd and 3rd year of evaluation. Haplotyping is a new tool for genetic characterization of FHBSN entries and helps to identify new resistance sources with novel resistance genes and to better target crosses toward diversifying and/or pyramiding resistance. The 13th FHBSN was taken as an example in this paper to show the procedure and strategy for the development of new FHB resistant lines.     

Shoot cadmium concentration of soil‐grown plants as related to their root properties

Cadmium (Cd) is toxic to plants, animals, and humans. However, different plant species growing on the same soil may have very different shoot Cd concentrations depending on properties such as size of the root system, Cd net influx, shoot‐growth rate, Cd translocation from root to shoot, and the ability to affect Cd availability in the soil. To investigate possible reasons for different shoot Cd concentrations maize, sunflower, flax, and spinach were grown on an acid sandy soil (pH<$>_{{\rm{(CaCl}}_{\rm{2}} {\rm)}<$> 4.5, and C_org 2.8%) in a growth chamber with Cd additions as Cd(NO₃)₂ of none, 14, and 40 μmol (kg soil)^–1 resulting in Cd soil‐solution concentrations of 0.04, 0.68, and 2.5 μM. Only the high Cd addition caused a significant growth reduction of flax and spinach. The shoot Cd concentration was up to 30 times higher in spinach than in maize; the other species were intermediate. Of the plant properties studied only the variation of the Cd net influx explained the differences in shoot Cd concentrations. This was due to a decreased (maize, sunflower) or increased (flax) Cd concentration in soil solution or more effective uptake kinetics (spinach).     

Amino acid catalysis of 2-alkylfuran formation from lipid oxidation-derived α,β-unsaturated aldehydes

The formation of 2-alkylfurans from the corresponding lipid-derived α,β-unsaturated aldehydes under dry-roasting conditions was investigated in detail. The addition of an amino acid to an α,β-unsaturated aldehyde drastically increased 2-alkylfuran formation. Peptides and proteins as well were able to catalyze 2-alkylfuran formation from the corresponding α,β-unsaturated aldehydes. Further investigation of 2-alkylfuran formation showed the need of oxidizing conditions and the involvement of radicals in the reaction. This way, the formation of 2-methylfuran from 2-pentenal, 2-ethylfuran from 2-hexenal, 2-propylfuran from 2-heptenal, 2-butylfuran from 2-octenal, 2-pentylfuran from 2-nonenal, and 2-hexylfuran from 2-decenal was shown. The impact of amino acids on 2-alkylfuran formation from lipid-derived α,β-unsaturated aldehydes represents an interesting example of the complex role of amino acids in the multitude of chemical reactions occurring during thermal processing of lipid-rich foods.     

Mechanistic insights into furan formation in Maillard model systems

Furan has recently received considerable attention as a possibly carcinogenic compound occurring in thermally processed foods. Although several food constituents have been identified as furan precursors, multiple formation pathways remain unclear. Therefore, the mechanisms of furan formation in Maillard model systems were studied by means of the carbon module labeling (CAMOLA) technique. Under both roasting and pressure-cooking conditions, furan was formed from glucose via the intact skeleton, and its formation pathways from glucose alone were not amino acid-dependent. However, some amino acids, especially alanine and serine, did influence the furan production by providing an additional formation pathway. Furthermore, most amino acids enhanced the furan production from glucose. Roasting conditions produced 25-100 times higher amounts of furan as compared to pressure-cooking conditions. Surprisingly, in the alanine/glucose model systems, the relative importance of furan production from glucose alone and from the combination of a glucose-derived and an alanine-derived fragment changed completely over a limited time course of 60 min.     

Rapid impact of Impatiens glandulifera control on above‐ and belowground invertebrate communities

The annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread invasive non‐native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post‐control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above‐ and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abundance increased with the removal of I. glandulifera, and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.     

Investigating landscape phase transitions in Mediterranean rangelands by recurrence analysis

Context

Socio-ecological landscapes typically characterized by non-linear dynamics in space and time are difficult to be analyzed using standard quantitative methods, due to multiple processes interacting on different spatial and temporal scales. This poses a challenge to the identification of appropriate approaches for analyzing time series that can evaluate system properties of landscape dynamics in the face of disturbances, such as uncontrolled fires.

Objective

The purpose is the application of non-linear methods such as recurrence quantification analysis (RQA) to landscape ecology. The examples concern the time series of burnt and unburnt Mediterranean rangelands, to highlight potential and limits of RQA.

Methods

We used RQA together with joint recurrence analysis (JRA) to compare the evolutionary behavior of different land uses.

Results

Time series of forests and grasslands in rangelands present both periodic and chaotic components with a rather similar behavior after the fire and clear transitions from less to more regular/predictable dynamics/succession. Results highlight the impacts of fire, the recovery capacity of land covers to pre-burnt levels, and the decay of synchronization towards the previous regime associated with vegetation secondary succession consistent with early successional species.

Conclusions

RQA and JRA with their set of indices (recurrence rate: RR, laminarity: LAM, determinism: DET, and divergence: DIV) can represent new sensitive measures that may monitor the adaptive capacity and the resilience of landscapes. However, future applications are needed to standardize the analysis by strengthening the accuracy of this approach in describing the ongoing transformations of natural and man-managed landscapes.