In vitro efficacy of N-duopropenide, a recently developed disinfectant containing quaternary ammonium compounds, against selected gram-positive and gram-negative organisms

OBJECTIVE: To study the efficacy of N-duopropenide against various gram-positive and gram-negative organisms. SAMPLE POPULATION: One field strain each of Pasteurella multocida subsp multocida, Staphylococcus aureus, Listeria monocytogenes, and L ivanovii, and 2 field strains of Escherichia coli. PROCEDURE: Strains were tested with and without serum as organic matter, using quantitative suspension and carrier tests. Six concentrations of active ingredient (0.005, 0.01, 0.05, 0.11, 0.27, and 0.55%) and 6 contact times (15 and 30 seconds and 1, 3, 5, and 10 minutes) were studied for each. RESULTS: Globally, N-duopropenide was more effective in suspension tests than in carrier tests, and when organisms were suspended in saline solution rather than serum. Under the most disadvantageous conditions (carrier test with serum), a concentration of 0.55% N-duopropenide acting for only 15 seconds was effective in inactivating P multocida subsp multocida and was even more effective against the 2 Listeria species tested. For E coli strains, the same concentration also was effective, but after 10 minutes of contact. On the other hand, N-duopropenide was unable to inactivate the S aureus strain in the carrier test with serum, a concentration of 0.55% for 10 minutes was necessary to inactivate it without organic matter; however, N-duopropenide was highly effective against this organism in the suspension test, even with serum. CONCLUSION: N-duopropenide was highly effective in vitro against 5 of the most commonly encountered organisms in clinical veterinary medicine and, consequently, might be a good choice in control measures against common pathogenic organisms in modern production systems.     

Modelling the spread of a viral infection in equine populations managed in Thoroughbred racehorse training yards

A Monte Carlo model that simulates the management life cycle of a horse population in training on a Thoroughbred flat racing yard (i.e. stable) was developed for computer implementation. Each horse was characterised by several state variables. Discrete events at the horse level were triggered stochastically to reflect uncertainty about some input assumptions and heterogeneity of the horse population in a particular yard. This mathematical model was subsequently used to mimic the spread of equine influenza (EI) within a typical yard following the introduction of one or several infectious horses. Different scenarios were simulated to demonstrate the value of strategies for preventing outbreaks of EI. Under typical UK management conditions and vaccination protocols, the model showed that EI would propagate and that the timing of vaccination in connection with the racing season and the arrival of new horses was a critical factor. The predicted outcomes (based on published characteristics of one EI vaccine) suggested that vaccination in mid-December with boosters in June and September was a viable and successful strategy in preventing the spread of EI in a training establishment.     

A diallel study of yield components and fruit quality in chilli pepper (<Emphasis Type="Italic">Capsicum baccatum</Emphasis>)

The aim of this work was to estimate the general and specific combining ability of peppers by measuring fruit quality and yield traits. This experiment was carried out on the garden field from Universidade Federal de Viçosa (UFV), Minas Gerais State—Brazil. Eight lines of Capsicum baccatum belonging to the UFV Horticultural Germplasm Bank were chosen based on their broad genetic and phenotypical background variation and then they were crossed in a complete diallel way. The F₁ seeds of the 56 hybrids and eight parents were planted in the field in a randomized complete block design. The data were submitted to ANOVA and the means were grouped by Scott–Knott test (P ≤ 0.01). Significant variation for fruit quality and yield components was observed among parents and F₁ generation. Analysis of variance for the combining ability showed that GCA effects exhibited significant difference and SCA effects of the crosses were significant, except for the height of first bifurcation. For almost all characters both additive and non-additive effects influenced the performance of hybrids.     

A shot in the dark for conservation: Evidence of illegal commerce in endemic and threatened species of elasmobranch at a public fish market in southern Brazil

1. The illegal sale of endangered elasmobranchs has been recorded in a number of different Brazilian states, where sharks and rays are being marketed primarily as ‘cação’ or ‘viola’. Brazil is ranked among the top 10 nations worldwide that harvest most sharks, causing an immeasurable impact on the local elasmobranch populations.
2. The present study applied the DNA barcoding technique, based on the cytochrome C oxidase subunit I gene, for the molecular identification of the elasmobranch species sold as processed products under the generic names of ‘cação’, ‘mangona’, ‘azul’, ‘cambeva’, ‘fiuso’ and ‘lombo preto’, in the fish market of the city of Florianópolis, capital of the state of Santa Catarina, Brazil.
3. Nine elasmobranch species were identified in the 56 samples analysed, including six sharks and three rays, representing six families, the Carcharhinidae, Sphyrnidae, Squatinidae, Arhynchobatidae, Myliobatidae and Gymnuridae. Prionace glauca, identified in more than half (56%) of the samples analysed, is listed as Near Threatened by the International Union for the Conservation of Nature.
4. Six species identified in the present study, Sphyrna zygaena, Sphyrna lewini, Squatina guggenheim, Carcharhinus signatus, Gymnura altavela and Rioraja agassizii, are under some level of risk of extinction, while two others (Rhizoprionodon lalandii and Myliobatis goodei) are listed as Data Deficient.
5. Our results indicate that the commercial exploitation of endemic sharks and rays at risk of extinction is commonplace in southern Brazil. This reinforces the need for more systematic monitoring of the trade in fishery products and more effective application of the environmental legislation and conservation programmes.

     

Short‐term effects of dietary soybean meal and lactic acid bacteria on the intestinal morphology and microbiota of Atlantic salmon (Salmo salar)

The aim of this study was to evaluate the role of the intestinal microbiota in soybean meal enteritis. Three groups of Atlantic salmon (Salmo salar) were fed for 35 days with different diets: a control diet (CD) containing 510 g kg^?1 fishmeal, diet 1 (D1) containing 378 g kg^?1 of soybean meal and diet 2 (D2) containing D1 supplemented with two viable lactic acid bacteria (LAB). As expected, the fish fed with D1 showed clear signs of distal intestinal inflammation during the study compared with the fish fed CD. For the fish fed with D2, the addition of LAB diminished the inflammation at day 28, but did not abolish it. Microbiological analysis demonstrated that specific bacterial groups were not correlated with the development of enteritis, but were correlated with the three diets. Microbacterium, Pseudomonas, Lactococcus lactis sp. cremoris and Aeromonas VIa were correlated with the CD, Aeromonas VIb and Sporosarcina aquimarina were correlated with D1, and Alcaligenes, Acinetobacter, L. lactis sp. lactis and Carnobacterium maltaromaticum were correlated with D2. Shewanella was not affected by the diet and was present in all fish intestines. Our study suggests that LAB may modulate intestinal inflammation; however, the role of the microbiota in the aetiology of enteritis in fish still requires further study.     

Organic matter stabilization in two Andisols of contrasting age under temperate rain forest

Recent studies with Andisols show that the carbon (C) stabilization capacity evolves with soil age relative to the evolution of the mineral phase. However, it is not clear how soil mineralogical changes during pedogenesis are related to the composition of soil organic matter (SOM) and ¹⁴C activity as an indicator for the mean residence time of soil organic matter (SOM). In the present study, we analyzed the contribution of allophane and metal–SOM complexes to soil C stabilization. Soil organic matter was analyzed with solid-state ¹³C nuclear magnetic resonance spectroscopy. Additionally, the soil was extracted with Na-pyrophosphate (Al_p, Fe_p) and oxalate (Al_o, Si_o, and Fe_o). Results supported the hypothesis that allophane plays a key role for SOM stabilization in deep and oldest soil, while SOM stabilization by metal (Al and Fe) complexation is more important in the surface horizons and in younger soils. The metal/C_p ratio (C_p extracted in Na-pyrophosphate), soil pH, and radiocarbon age seemed to be important indicators for formation of SOM–metal complexes or allophane in top- and subsoils of Andisols. Changes in main mineral stabilization agents with soil age do not influence SOM composition. We suggest that the combination of several chemical parameters (Al_p, Fe_p and C_p, metal/C_p ratio, and pH) which change through soil age controls SOM stabilization.     

Organic‐carbon and nitrogen stocks and organic‐carbon fractions in soil under mixed pine and oak forest stands of different ages in NE Germany

The objective of this work was to evaluate the C and N stocks and organic‐C fractions in soil under mixed forest stands of Scots pine (Pinus sylvestris L.) and Sessile oak (Quercus petraea [Matt.] Liebl.) of different ages in NE Germany. Treatments consisted of pure pine (age 102 y), and pine (age 90–102 y) mixed with 10‐, 35‐, 106‐, and 124‐y‐old oak trees. After sampling O layers, soils in the mineral layer were taken at two different depths (0–10 and 10–20 cm). Oak admixture did not affect total organic‐C (TOC) and N stocks considering the different layers separately. However, when the sum of TOC stocks in the organic and mineral layers was considered, TOC stocks decreased with increasing in oak age (r² = 0.58, p < 0.10). The microbial C (C_MB) was not directly correlated with increase of oak age, however, it was positively related with presence of oak species. There was an increase in the percentage of the C_MB‐to‐TOC ratio with increase of oak‐tree ages. On average, light‐fraction C (C_LF) comprised 68% of the soil TOC in upper layer corresponding to the highest C pool in the upper layer. C_LF and heavy‐fraction C (C_HF) were not directly affected by the admixture of oak trees in both layers. The C_HF accounted on average for 30% and 59% of the TOC at 0–10 and 10–20 cm depths, respectively. Despite low clay contents in the studied soils, the differences in the DCB‐extractable Fe and Al affected the concentrations of the C_HF and TOC in the 10–20 cm layers (p < 0.05). Admixture of oak in pine stands contributed to reduce topsoil C stocks, probably due to higher soil organic matter turnover promoted by higher quality of oak litter.     

Effect of inoculation with Azotobacter chroococcum on nitrogenase activity of Zea mays roots grown in agricultural soils under aseptic and non-sterile conditions

Summary Inoculated and non-inoculated seedlings of Zea mays were grown in agricultural soils under aseptic and non-sterile conditions. Acetylene reduction activity and microbial counts were determined after 7 and 30 days of growth. Irrespective of the soil type Azotobacter spp. were commonly isolated under maize cultivation. Inoculation of agricultural soils with a suspension of A. chroococcum led to an increase in Azotobacter numbers, although this effect diminished with time. Nitrogenase activity was detected on maize roots and increased in response to the inoculation with A. chroococcum, showing that this associative growth could be of primary importance for the plant. The results of assays for acetylene reduction activity indicated that the nitrogenase activity was associated only with the root systems.