Induction and synchronization of pregnancy in cows

Inductions and synchronizations of parturitions by the analogue PG F2alpha, Cloprostenol, were tested in cows under production conditions. The average time from induction to delivery is 40.5 hours (33-49 hours). No significant relation exists between the length of gravidity and the time of delivery induction (correlation coefficient = -0.325). A scheme was proposed from the system of calving days in cows to organize synchronized parturitions. In production conditions the induction and synchronization of cow parturitions cannot be recommended because amnions are retained frequently (69.7%). No relationship was demonstrated between gravidity length at the time of delivery induction and the order of parturition in the cow (first-calver-cow).     

Pathological,ultrastructural, and immunohistochemical changes caused by Lelystad virus in experimentally induced infections of mystery swine disease (synonym: Porcine epidemic abortion and respiratory syndrome (PEARS))

Summary

The pathogenicity and pathogenesis of Lelystad virus was studied in six 6‐day‐old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re‐isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum.

Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences.     

Selenite interactions with some particulate organic and mineral fractions isolated from a natural grassland soil

The nature of the main selenium (Se) carrier phases in soil is in debate, with some authors emphasizing the role of minerals, and others the role of organic material. In this study, we address the role of the different soil components in Se sorption by determining its interaction with easily separable and workable fractions of bulk soil. Thus four separated fractions (two organic and two mineral) isolated by size density fractionation from a grassland soil were taken as models for soil Se carrier phases. Two concentrations of selenite were used to estimate its reactivity during experiments. In addition, SEM-TEM analyses (coupled with EDS) were used to determine the chemical environment of Se sorbed onto the different fractions. The results showed that for the smaller selenite concentration nearly all the fractions gave the same selenite sorption (approximately 99%). For the larger concentration, selenite sorption ranged between 44% (mineral fractions) and 93% (organic fractions), indicating that the sorption capacities of organic fractions were greater than those of mineral fractions. In all soil fractions, elementary analyses and SEM/EDS and TEM/EDS observations revealed that Se sorption and the detection of Se hot spots on the soil particles correlated with the presence of Fe and Al. Although a direct association between Se and organic material could not be excluded, we suggest that Se sorption on organic particles is indirect, mainly resulting from association with surface Fe oxides or clays. These findings question the current view of a direct correlation between organic carbon and Se in natural soil samples.     

Model‐Based Prediction of Nephropathia Epidemica Outbreaks Based on Climatological and Vegetation Data and Bank Vole Population Dynamics

Wildlife‐originated zoonotic diseases in general are a major contributor to emerging infectious diseases. Hantaviruses more specifically cause thousands of human disease cases annually worldwide, while understanding and predicting human hantavirus epidemics pose numerous unsolved challenges. Nephropathia epidemica (NE) is a human infection caused by Puumala virus, which is naturally carried and shed by bank voles (Myodes glareolus). The objective of this study was to develop a method that allows model‐based predicting 3 months ahead of the occurrence of NE epidemics. Two data sets were utilized to develop and test the models. These data sets were concerned with NE cases in Finland and Belgium. In this study, we selected the most relevant inputs from all the available data for use in a dynamic linear regression (DLR) model. The number of NE cases in Finland were modelled using data from 1996 to 2008. The NE cases were predicted based on the time series data of average monthly air temperature (°C) and bank voles’ trapping index using a DLR model. The bank voles’ trapping index data were interpolated using a related dynamic harmonic regression model (DHR). Here, the DLR and DHR models used time‐varying parameters. Both the DHR and DLR models were based on a unified state‐space estimation framework. For the Belgium case, no time series of the bank voles’ population dynamics were available. Several studies, however, have suggested that the population of bank voles is related to the variation in seed production of beech and oak trees in Northern Europe. Therefore, the NE occurrence pattern in Belgium was predicted based on a DLR model by using remotely sensed phenology parameters of broad‐leaved forests, together with the oak and beech seed categories and average monthly air temperature (°C) using data from 2001 to 2009. Our results suggest that even without any knowledge about hantavirus dynamics in the host population, the time variation in NE outbreaks in Finland could be predicted 3 months ahead with a 34% mean relative prediction error (MRPE). This took into account solely the population dynamics of the carrier species (bank voles). The time series analysis also revealed that climate change, as represented by the vegetation index, changes in forest phenology derived from satellite images and directly measured air temperature, may affect the mechanics of NE transmission. NE outbreaks in Belgium were predicted 3 months ahead with a 40% MRPE, based only on the climatological and vegetation data, in this case, without any knowledge of the bank vole’s population dynamics. In this research, we demonstrated that NE outbreaks can be predicted using climate and vegetation data or the bank vole’s population dynamics, by using dynamic data‐based models with time‐varying parameters. Such a predictive modelling approach might be used as a step towards the development of new tools for the prevention of future NE outbreaks.     

Caveolin-1 is essential for liver regeneration

Liver regeneration is an orchestrated cellular response that coordinates cell activation, lipid metabolism, and cell division. We found that caveolin-1 gene-disrupted mice (cav1-/- mice) exhibited impaired liver regeneration and low survival after a partial hepatectomy. Hepatocytes showed dramatically reduced lipid droplet accumulation and did not advance through the cell division cycle. Treatment of cav1-/- mice with glucose (which is a predominant energy substrate when compared to lipids) drastically increased survival and reestablished progression of the cell cycle. Thus, caveolin-1 plays a crucial role in the mechanisms that coordinate lipid metabolism with the proliferative response occurring in the liver after cellular injury.     

Increased mortality of fish due to changing Al-chemistry of mixing zones between limed streams and acidic tributaries

The present study is mainly focusing on mortality variations of fish due to changing Alchemistry of mixing zones. An artificial mixing zone was made by pumping water from a limed stream and an acidic tributary into a mixing channel. Atlantic salmon (Salmo salar L.) parr were exposed to the mixed water, limed stream water, and acidic tributary water. Mortality, blood haematocrit and plasma Cl^?-concentration were recorded. Neither mortality, nor changes in haematocrit and plasma Cl^? were observed when fish were exposed to limed water, while in both acidic and mixed water, mortalities and loss of plasma Cl^? were observed. The highest mortality rates were found within the initial part (0 to 20 s) of the mixing zone. Blood haematocrit increased only in fish exposed to acidic tributary water. Our results shows that changes in Al-chemistry and subsequent Al-polymerization occur when acidic tributary water is mixed with limed stream water. We have also demonstrated that the toxicity which can arise in mixing zones are greater than in the original acidic water before mixing. The variations in mortality observed are associated with the quality and quantity of Al-polymerization as well as ageing of the polymers.     

Verschijnselen bij diverse tuinbouwgewassen,die in verband staan met de droge en warme zomer

Summary Phenomenon on various crops due to drought, heat, sunscald, sudden rain after drought and strong temperature changes are described.     

Bembecia hylaeiformis lasp., een weinig voorkomende beschadiger van de framboos (rubus idaeus L.)

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