Effects of experimental inoculation of bovine respiratory syncytial virus in different inbred mice lineages: establishment of a murine model for BRSV infection

Bovine respiratory syncytial virus (BRSV), a member of the subfamily Pneumovirinae, family Paramyxoviridae, is a major cause of respiratory disorders in young cattle. A number of studies were conducted to validate a reliable animal model for the infection, since BRSV inoculation on the natural host is costly and often unsuccessful. Unfortunately, after inoculation of BRSV in Balb/C mice, viral replication may be detected; however, evident pathological alterations are absent on the experimentally infected animals. In order to establish a mice model that could be used further for preliminary studies of pathological and immunological aspects of BRSV infection, three mice inbred lineages (Balb/C, A/J and C57BL6), possessing different genetic backgrounds, were tested about its susceptibility to the inoculation with BRSV. Animals were inoculated through the nasal and ocular routes and were observed after inoculation. At 7 days post-inoculation (dpi) animals were necropsied and virological (virus isolation and viral nucleic acid amplification) as well as histopathological examinations were performed. A/J and C57BL6 showed interstitial pneumonia, when compared to the Balb/C group. These findings shows that mice may constitute a suitable model for the study of BRSV infections, depending on the mice strain used for experimental inoculations.     

Assessment of the plant growth promotion abilities of six bacterial isolates using Zea mays as indicator plant

Zea mays, one of the most important cereals worldwide, is a plant not only with food and energy value, but also with phytoremediation potential. The use of plant growth promoting (PGP) rhizobacteria may constitute a biological alternative to increase crop yield and plant resistance to degraded environments. In search for PGP rhizobacteria strains, 6 bacterial isolates were isolated from a metal contaminated site, screened in vitro for their PGP characteristics and their effects on the growth of Z. mays were assessed. Isolates were identified as 3A10^T, ECP37^T, corresponding to Chryseobacterium palustre and Chryseobacterium humi, and 1ZP4, EC15, EC30 and 1C2, corresponding to strains within the genera Sphingobacterium, Bacillus, Achromobacter, and Ralstonia, respectively. All the bacterial isolates were shown to produce indole acetic acid, hydrogen cyanide and ammonia when tested in vitro for their plant growth promoting abilities, but only isolates 1C2, 1ZP4 and ECP37^T have shown siderophore production. Their further application in a greenhouse experiment using Z. mays indicated that plant traits such as root and shoot elongation and biomass production, and nutrient status, namely N and P levels, were influenced by the inoculation, with plants inoculated with 1C2 generally outperforming the other treatments. Two other bacterial isolates, 1ZP4 and ECP37^T also led to increased plant growth in the greenhouse. These 3 species, corresponding to strains within the genera Ralstonia (1C2), Sphingobacterium (1ZP4), and to a strain identified as C. humi (ECP37^T) can thus be potential agents to increase crop yield in maize plants.     

Effect of invasive Acacia dealbata Link on soil microorganisms as determined by PCR-DGGE

Acacia dealbata Link is an Australian woody legume that has become a serious environmental problem in Northwest Spain where it forms dense monospecific patches modifying the structure of different native ecosystems and threatening native aboveground biodiversity. In spite of the dramatic changes observed in the vegetation of invaded sites little is known about the consequences of invasion for soil microorganisms. To investigate the effect of A. dealbata invasion on the structure of soil fungi and bacteria communities, samples were taken from invaded and non-invaded areas from three different ecosystems in Northwest Spain: pine forest, shrubland and grassland. In each ecosystem type, soil samples were taken in areas of native vegetation, areas invaded by A. dealbata and in the transition zone between native and invaded vegetation. Soil microorganisms were analyzed in the different samples by PCR-DGGE using general primers for eubacteria and fungi. Soil analyses were also performed to evaluate the effect of A. dealbata invasion on soil fertility.The invasion by A. dealbata consistently increased soil N, C, organic matter and exchangeable P content in the three studied ecosystems. A clear effect of the invasion on the overall structure of microorganism communities was only observed in the shrubland where soil fungal communities in the invaded and transition areas clustered together and apart from the native soil. Significant differences in soil microorganisms richness and diversity between invaded and not invaded soils were only found in the grassland. Grassland invasion by A. dealbata lead to a significant increase of bacterial richness and to a significant reduction in fungal richness and diversity. Our results show that although the changes on soil chemistry due to A. dealbata invasion are consistent among the studied ecosystems, the effect on soil microorganisms depends on the ecosystem type affected by the invasion.     

Enzymatic cleaning of inorganic ultrafiltration membranes fouled by whey proteins

The aim of this work was to study the cleaning of inorganic membranes fouled with whey protein solutions using the enzymatic formulation Alcalase (Novo Nordisk A/S). Hydraulic and chemical methods were considered to characterize the cleanliness of the membranes. Cleaning efficiency was observed to be a function of the operating conditions. The operating conditions tested were the following: recycling versus non-recycling of permeate, pH of the cleaning solution, addition of alkali to regulate the pH, enzymatic agent concentration, and cleaning time. The best conditions to perform the cleaning were related to the best conditions to hydrolyze whey proteins in a discontinuous reactor using the same enzyme preparations. Very high cleaning efficiencies (>90%) were achieved in short operating times (20 min). However, residual matter was observed on the membrane surface.     

Serologic monitoring of a broiler breeder flock previously affected by inclusion body hepatitis and testing of the progeny for vertical transmission of fowl adenoviruses

The increasing number of clinical cases of inclusion body hepatitis (IBH) associated with fowl adenoviruses (FAdVs) is a growing concern in different parts of the world, including Canada. After an outbreak of IBH in a 10-d-old pullet broiler breeder flock, we serologically monitored the flock from 8 to 46 wk of age, using the agar gel precipitation test (AGPT) offered by diagnostic laboratories and an FAdV group-specific enzyme-linked immunosorbemt assay (ELISA) developed earlier. In addition, we tested 1-d-old progeny for possible vertical transmission of FAdV when the breeder flock approached the peak of egg production by performing virus isolation and polymerase chain reaction (PCR) procedures on target organs. As in previous studies comparing the 2 tests, ELISA was more sensitive than AGPT. With ELISA, a few birds had weakly positive results at 8 wk of age, and all the birds had strongly positive results from 12 wk of age until the end of the study. This group-specific ELISA is therefore a sensitive and practical way to monitor FAdV antibodies in commercial flocks. None of the 1-d-old chicks tested were positive by PCR, nor was FAdV isolated from the same tissues, indicating an absence of transmission of infectious virus to the progeny. The lack of virus production and transmission could be due to the presence of high antibody titers in the layers.     

Aluminum toxicity in maize: Biomass production and nutrient uptake and translocation

The effect of increasing aluminum (Al) concentrations on root nutrient contents along with the concurrent translocation to the shoot of C₄ plants prompted this study. Two‐week‐old maize (Zea mays cv XL‐72.3) plants were therefore submitted for 20 days to Al concentrations ranging from 0 to 3.00 mM in a medium with low ionic strength were used as a test system. Aluminum concentrations in root tissues showed a 3‐fold increase between 0 and 3.00 mM Al treatment, and was not detected in the shoot. Root plasma membrane‐H⁺ ATPase activity decreased after the 0.33 mg L^‐1 Al treatment, while membrane permeability increased up to 1.00 mM Al treatment. Root and shoot biomass decreased after the 0.33 mM Al treatment. All elements in the roots, except potassium (K), manganese (Mn), and zinc (Zn) were highest for plants treated with 0.33 mM Al. Potassium increased continuously between 0 and 3.00 mM Al treatments, and iron (Fe) decreased above 0.33 mM. Only a slight decrease in nitrogen (N) was observed. All the measured nutrients in shoots, except N, Mn, and Fe decreased above 0.33 mM, but calcium (Ca) and magnesium (Mg) had little variation as Al varied. Data indicated that maximum net uptake for mineral nutrients, except Mn, occurred up to 0.33 mM Al. Translocation of phosphorus (P), K, Mn, and Zn decreased above 0.33 mM Al, N, and Ca decreased when any Al was added, and no clear trend was observed for Mg and Fe. Between the 0 and the 3.00 mM Al treatments, electrolytic conductance did not increased significantly indicating that the observed inhibitions of translocation from roots to shoots were not directly related to increasing membrane degradation.     

Effect of processing and storage on the stability of flaxseed lignan added to bakery products

The study focused on the effects of processing and storage on the stability of flaxseed-derived secoisolariciresinol diglucoside (SDG) added to various bakery products. The SDG concentration of doughs, baked rye breads, graham buns, and muffins was analyzed by high-performance liquid chromatography-diode array detection; the baked products were analyzed immediately after baking and upon storage at room temperature for 1 week and at -25 degrees C for 1 and 2 months, respectively. Added SDG was found to withstand normal baking temperatures in all bakery products. SDG also was a relatively stable compound during storage. Similarly, the content of SDG in flax buns containing fat-free flaxseed meal was unaffected by storage. We conclude that cereal-based bakery products can be supplemented with flaxseed-derived SDG.     

Influence of water depth and soil amelioration on greenhouse gas emissions from peat soil columns

Recently, large areas of tropical peatland have been converted into agricultural fields. To be used for agricultural activities, peat soils need to be drained, limed and fertilized due to excess water, low nutrient content and high acidity. Water depth and amelioration have significant effects on greenhouse gas (GHG) production. Twenty-seven soil samples were collected from Jabiren, Central Kalimantan, Indonesia, in 2014 to examine the effect of water depth and amelioration on GHG emissions. Soil columns were formed in the peatland using polyvinyl chloride (PVC) pipe with a diameter of 21 cm and a length of 100 cm. The PVC pipe was inserted vertically into the soil to a depth of 100 cm and carefully pulled up with the soil inside after sealing the bottom. The treatments consisting of three static water depths (15, 35 and 55 cm from the soil surface) and three ameliorants (without ameliorant/control, biochar+compost and steel slag+compost) were arranged using a randomized block design with two factors and three replications. Fluxes of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) from the soil columns were measured weekly. There was a linear relationship between water depth and CO₂ emissions. No significant difference was observed in the CH₄ emissions in response to water depth and amelioration. The ameliorations influenced the CO₂ and N₂O emissions from the peat soil. The application of biochar+compost enhanced the CO₂ and N₂O emissions but reduced the CH₄ emission. Moreover, the application of steel slag+compost increased the emissions of all three gases. The highest CO₂ and N₂O emissions occurred in response to the biochar+compost treatment followed by the steel slag-compost treatment and without ameliorant. Soil pH, redox potential (Eh) and temperature influenced the CO₂, CH₄ and N₂O fluxes. Experiments for monitoring water depth and amelioration should be developed using peat soil as well as peat soil–crop systems.     

Prevalence of extra-intestinal porcine helminth infections and assessment of sanitary conditions of pig slaughter slabs in Dar es Salaam city,Tanzania

A study was carried out to establish the prevalence of extra-intestinal porcine helminth infections and to assess the pig slaughter slab sanitary conditions in Dar es Salaam city, Tanzania. A total of 24 privately owned pig slaughter slabs were assessed. All slaughter slabs were sub-standard; wrongly located, poorly designed and constructed and lacked most basic requirements for a slaughter house. Because of inadequate slaughtering, disposal and cleaning facilities, the slaughter slabs were under unhygienic condition with questionable safety, soundness and wholesomeness of the pork produced. Routine meat inspection procedures were used to detect extra-intestinal porcine helminth infections. Of the 731 examined pigs; 8.1%, 5.9% and 0.4% were infected with ascariosis, porcine cysticercosis and hydatidosis, respectively. It was noted that almost all slaughter pigs in Dar es Salaam originated from different regions. Based on the region of origin, the status of porcine cysticercosis was 8.2% for Dodoma (n = 98), 8.2% for Manyara (n = 260) and 6.9% for Mbeya (n = 116). This study disclosed the unhygienic sanitary condition prevailing in Dar es Salaam pig slaughter slabs and recommends that strategies should be devised to improve the situation. Porcine ascariosis and cysticercosis were widely prevalent and caused economic losses due to condemnations. Because of their zoonotic nature, the observed extra-intestinal porcine helminth infections in pig pose a public health risk among consumers. Thus, there is a need to introduce appropriate control measures of parasitic infections in pigs.     

The use of gelatine in long‐term storage (up to 48 hr) at 5°C preserves the pre‐freezing and post‐thawing quality of brown bear sperm

Sedimentation of spermatozoa occurs during long‐term liquid storage and this may produce deleterious changes. Our aim was to apply gelatine supplementation during long‐term pre‐freezing storage of bear sperm, applying final dilution and 6% glycerol at room temperature and cool in straws. We tested four models of sperm storage using a 1:1 dilution in TTF‐ULE‐Bear extender (TesT‐fructose‐egg yolk‐glycerol 6%): (i) second 1:1 dilution at room temperature (RT), cooling at 5°C in a tube and final dilution (100 × 10⁶ sperm ml^?1) (Standard); (ii) final dilution at RT and cooling in a tube (FD‐Tube); (iii) final dilution at RT and cooling in 0.25 ml plastic straw (FD‐Straw); and (iv) final dilution at RT in extender supplemented with 1.5% gelatine (Gelatine) and cooling in a 0.25 ml plastic straw. A Standard sample was stored at 5°C for 1 hr (Control); the rest of the samples (Standard, FD‐Tube, FD‐Straw, Gelatine) were stored for 24 or 48 hrs before freezing (100 × 10⁶ sperm ml^?1, glycerol 6%). The quality of the samples was assessed for motility by CASA, and viability (SYBR‐14/propidium iodide‐PI‐; VIAB), acrosomal status (PNA‐FITC/PI; iACR) and apoptotic status (YO‐PRO‐1/PI; YOPRO‐) by flow cytometry. At pre‐freezing, after 48 hr, Gelatine showed significantly higher viability (for VIAB and YOPRO‐) and progressiveness (PM, LIN and STR). At 48 hr, Gelatine showed similar YOPRO‐, iACR, LIN, STR and ALH respect to Control. At both 24 and 48 h post‐thawing, Gelatine sample had similar scores for YOPRO‐, iACR, LIN, STR, WOB and VIAB (only 24 hr) when compared with Control, and lower for TM, PM, rapidPM, VAP and ALH. No differences were found among others experimental groups with respect to Control. In conclusion, gelatine could be a suitable alternative to preserve the viability and progressive motility of brown bear ejaculates during long‐term pre‐freezing storage at 5°C.