Porcine circovirus type 2 in muscle and bone marrow is infectious and transmissible to naïve pigs by oral consumption

Pork products are a possible source of introduction of PCV2 isolates into a pig population. However, limited work has been done on the transmission through meat of porcine circovirus type 2 (PCV2), a virus associated with several disease syndromes in pigs. The objectives of this study were to determine if pork products from PCV2-infected pigs contain PCV2 DNA/antigen and to determine if the PCV2 present in the tissues is infectious by performing in vitro and in vivo studies. Skeletal muscle, bone marrow, and lymphoid tissues from pigs experimentally inoculated with PCV2 were collected 14 days post-inoculation (DPI). The tissues were tested for presence of PCV2 DNA by quantitative real-time PCR, for PCV2 antigen by immunohistochemistry (IHC), and for presence of infectious PCV2 by virus isolation and inoculation of PCV2 naïve pigs. Lymphoid tissues contained the highest amount of PCV2 (positive by PCR, IHC, and virus isolation), bone marrow contained a lower amount of PCV2 (positive by PCR and IHC but negative by virus isolation), and skeletal muscle contained the lowest amount of PCV2 (positive by PCR but negative by IHC and virus isolation). Naïve pigs fed for three consecutive days with either skeletal muscle, bone marrow, or lymphoid tissues all became PCV2 viremic as determined by quantitative real-time PCR on serum starting at 7 DPI. The pigs also seroconverted to PCV2 as determined by PCV2 IgM and IgG ELISA. In addition, PCV2 antigen was detected by IHC stains in lymphoid tissues and intestines collected from the majority of these pigs. Results from this study indicate that uncooked PCV2 DNA positive lymphoid tissues, bone marrow, and skeletal muscle from PCV2 viremic pigs contain sufficient amount of infectious PCV2 to infect naïve pigs by the oral route.     

Effects of endophytic Bacillus spp. on accumulation and distribution of iron in the shoots of lowland rice grown under iron toxic conditions

Background

The tolerance of plants against abiotic stresses can be greatly influenced by their interaction with microbes. In lowland rice (Oryza sativa) production, the iron toxicity of the soils constitutes a major constraint. Although there are tolerant cultivars, the mechanisms underlying the tolerance against excess iron are not fully understood. Even less is known about the role of microbes in the response to iron toxicity.

Aim

In the study presented here, the effects of different Bacillus isolates on the accumulation and distribution of iron within the shoots of different rice cultivars grown under iron toxicity were analyzed.

Methods

Three lowland rice cultivars with contrasting tolerance to iron toxicity (IR31785-58-1-2-3-3, Sahel 108, Suakoko 8) were inoculated with three Bacillus isolates (two B. pumilus and one B. megaterium) and, after 1 week, exposed to excess iron (1,000 ppm) for 8 days. Tolerance was evaluated by leaf symptom scoring.

Results

Bacterial inoculation mitigated leaf symptoms in the sensitive cultivar IR31785-58-1-2-3-3 despite no significant differences in shoot iron concentration between inoculated and noninoculated plants. In the tolerant excluder cultivar, Suakoko 8, leaf symptoms were exacerbated when inoculated with B. pumilus Ni9MO12. While the total shoot Fe concentration was not affected in this bacteria × cultivar combination, the distribution of iron within the shoot was clearly disturbed. Tolerance to iron toxicity of the tolerant includer cultivar, Sahel 108, was not affected by Bacillus inoculation.

Conclusion

In conclusion, our results show that Bacillus inoculation can affect the tolerance of lowland rice to iron toxicity and that the effects strongly depend on the bacteria × cultivar combination.     

Cruciferous plants' use as biofumigants in potato against wireworms

In Slovenia, only tefluthrin is registered for controlling wireworms. In order to investigate the potential alternatives for controlling wireworms in potato, the field experiment was conducted in the period from 2011 (year 1) to 2012 (year 2). As alternatives, different Brassica crops (year 1: rapeseed, oilseed radish and white mustard; year 2: rapeseed, oilseed radish, oilseed rape, kale and white mustard) were tested (fresh foliage was incorporated into the soil by ploughing) for their biofumigant effect. Results of our investigation showed that in both years the potato yield was affected by measures of pest control; however, none of the tested biofumigant plants proved to be a potentially promising candidate in wireworm control. The rapid release of volatiles after plant chopping before and during incorporation into the soil could be the reason of inefficacy in our experiment. In our study, most wireworm damage occurred on biggest potato tubers. Moreover, edge effect of the field played an important role in our experiment in year 1. Treatment (chemical or biological) of wireworms only at the edge part of the field could offer a cost-effective, time-saving and environmentally more friendly way of controlling studied pest organism.     

Serological assays to discriminate rabbit haemorrhagic disease virus from Australian non-pathogenic rabbit calicivirus

Serological cross reactivity between the virulent rabbit haemorrhagic disease virus (RHDV) and the closely related but non-pathogenic rabbit calicivirus (RCV) makes it difficult to study the epidemiology of each virus and the interaction between them when both viruses co-circulate in wild rabbit populations. ELISA methods for the diagnosis of RHDV infection are well characterized, but no specific serological tests for RCV have been developed. Following the characterization of Australian non-pathogenic RCV-A1 strains, we used virus-like-particles (VLPs) and anti-RCV-A1 specific antibodies to establish a set of isotype ELISAs for detection of IgG, IgA and IgM in rabbit sera and secretory mucosal IgA in rectal swabs, and two competition ELISAs. These assays were used to discriminate between anti-RCV-A1 and anti-RHDV antibodies in rabbits. The isotype ELISAs were highly sensitive for detection of anti-RCV-A1 antibodies, but varying levels of cross reactivity from anti-RHDV antibodies occurred in the isotype ELISAs and one competition ELISA. However, the second competition ELISA specifically detected antibodies to RCV-A1 and showed no cross reactivity to anti-RHDV sera. These ELISAs provide important tools to monitor RCV-A1 infection when it occurs alone, and to discriminate between RHDV and RCV-A1 infection when they occur in the same rabbit population. When used in parallel with RHDV serology, they could be used to monitor the dynamics of these two closely related but pathogenically distinct viruses in wild and domestic rabbit populations.     

Mass spectrometric dereplication of nitrogen-containing constituents of black cohosh (Cimicifuga racemosa L.)

Black cohosh preparations are popular dietary supplements among women seeking alternative treatments for menopausal complaints. For decades, triterpene glycosides and phenolic acids have dominated the phytochemical and biomedical research on this plant. In this study, we provide evidence that black cohosh contains an unexpected and highly diverse group of secondary nitrogenous metabolites previously unknown to exist in this plant. Using a dereplication approach that combines accurate mass measurements, database searches and general knowledge of biosynthetic pathways of natural products, we identified or tentatively identified 73 nitrogen-containing metabolites, many of which are new natural products. The identified compounds belong to several structural groups including alkaloids, amides or esters of hydroxycinnamic acids and betains. Among the alkaloids, several classes such as guanidino alkaloids, isoquinolines and β-carbolines were identified. Fragmentation patterns for major compound classes are discussed, which provides a framework for the discovery of these compounds from other sources. Identification of alkaloids as a well-known group of bioactive natural products represents an important advance in better understanding of the pharmacological profile of black cohosh.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

Silicon dynamics in the rhizosphere: Connections with iron mobilization

Silicon (Si) is a beneficial element for plants as it increases their resistance to several biotic and abiotic stresses. In the rhizosphere, root exudates, especially when released by nutritionally stressed plants, promote the mineral weathering and, consequently, influence Si biogeochemistry. This study aims at evaluating the mineralogical alterations in the rhizosphere of Fe‐deficient or Fe‐sufficient barley plants grown either in a natural or in an artificial calcareous soil, focusing on the dynamics of both Fe and Si. After 6 d of soil–plant contact, X‐ray diffraction (XRD) analysis of rhizosphere soil samples of Fe‐deficient plants revealed, for both natural and artificial soil, a decrease of amorphous phases and an increase of smectite compared to the unplanted soil. Root exudates released by Fe‐deficient plants were most likely the main responsible for the weathering of the amorphous phases by a ligand controlled dissolution mechanism. When the soil–plant contact was prolonged up to 12 d, plants overcame Fe nutritional stress and their effect on soil mineralogy completely changed, as proved by the considerable increase of amorphous and decrease of smectite. Smectite decrease might evidence the effort of plant to mobilize Si and micronutrients other than Fe from the soil through the exudation of organic ligands. When the artificial soil was treated with Fe‐sufficient barley plants, the mineral weathering trend appeared reversed compared to the experiments with Fe‐deficient plants. Plant nutritional status regulates the root exudation pattern and, consequently, drives mineral weathering processes in the rhizosphere. Barley has shown to be able to mobilize Si from smectite, yet depending on its Fe supply and proving the strict connection between Si and Fe dynamics in the rhizosphere.     

Right flank laparotomy and abomasotomy for removal of a phytobezoar in a standing cow

A 4.5-year-old Holstein-Friesian cow underwent surgery because of left abomasal displacement. Intra-operative palpation of the pyloric region revealed a phytobezoar. The abomasum containing the phytobezoar was exteriorized, and an incision was made directly over the mass in the region of the greater curvature of the pyloric part of the abomasum.