Genotypic characterization by spoligotyping and VNTR typing of Mycobacterium bovis and Mycobacterium caprae isolates from cattle of Tunisia     

Hela Lamine-Khemiri  Remigio Martínez  Waldo Luis García-Jiménez  Jose Manuel Benítez-Medina  Maria Cortés  Inés Hurtado  Mohammed Salah Abassi  Imed Khazri  Mohammed Benzarti  Javier Hermoso-de-Mendoza 《Tropical animal health and production》2014,46(2):305-311

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In silico prediction of Gallibacterium anatis pan-immunogens     

Ragnhild J Bager  Egle Kudirkiene  Isabelle da Piedade  Torsten Seemann  Tine K Nielsen  Susanne E Pors  Andreas H Mattsson  John D Boyce  Ben Adler  Anders M Bojesen 《Veterinary research》2014,45(1)

The Gram-negative bacterium Gallibacterium anatis is a major cause of salpingitis and peritonitis in commercial egg-layers, leading to reduced egg production and increased mortality. Unfortunately, widespread multidrug resistance and antigenic diversity makes it difficult to control infections and novel prevention strategies are urgently needed. In this study, a pan-genomic reverse vaccinology (RV) approach was used to identify potential vaccine candidates. Firstly, the genomes of 10 selected Gallibacterium strains were analyzed and proteins selected on the following criteria; predicted surface-exposure or secretion, none or one transmembrane helix (TMH), and presence in six or more of the 10 genomes. In total, 42 proteins were selected. The genes encoding 27 of these proteins were successfully cloned in Escherichia coli and the proteins expressed and purified. To reduce the number of vaccine candidates for in vivo testing, each of the purified recombinant proteins was screened by ELISA for their ability to elicit a significant serological response with serum from chickens that had been infected with G. anatis. Additionally, an in silico prediction of the protective potential was carried out based on a protein property prediction method. Of the 27 proteins, two novel putative immunogens were identified; Gab_1309 and Gab_2312. Moreover, three previously characterized virulence factors; GtxA, FlfA and Gab_2156, were identified. Thus, by combining the pan-genomic RV approach with subsequent in vitro and in silico screening, we have narrowed down the pan-proteome of G. anatis to five vaccine candidates. Importantly, preliminary immunization trials indicated an in vivo protective potential of GtxA-N, FlfA and Gab_1309.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0080-0) contains supplementary material, which is available to authorized users.  相似文献   

Post-emergent herbicidal activity of cineole derivatives   总被引：1，自引：0，他引：1  

Allan F. M. Barton  Brenton R. Clarke  Bernard Dell  Allan R. Knight 《Journal of pest science》2014,87(3):531-541

Essential oils are being investigated as potential herbicides or to provide leads to new environmentally and socially acceptable herbicides. Novel hydroxy and ester derivatives of 1,8-cineole and 1,4-cineole were synthesised, by chemical and biological methods, and have shown pre-emergence herbicidal activity against annual ryegrass and radish. Effects on post-emergence activity of these derivatives, as well as 1,8-cineole, eucalyptus oil and the carboxylic acids from which the esters were derived, against annual ryegrass and radish, are reported here. Results suggest that reduced root and shoot growth observed in pre-emergence herbicidal bioassays were due to post-emergence activity rather than delayed germination. All tested substances had a dose-dependent, post-emergence herbicidal activity against annual ryegrass and radish with many derivatives showing improved activity relative to 1,8-cineole and high-cineole eucalyptus oil. However, results do not support the postulate that cineole esters would be more active than their respective carboxylic acid and the hydroxy cineole. Phytotoxicity of ester derivatives may be due to metabolic cleavage of the esters to the hydroxy cineole and carboxylic acid within the plant.  相似文献   

Early weaning of winter flounder (Pseudopleuronectes americanus Walbaum) larvae on a commercial microencapsulated diet   总被引：1，自引：0，他引：1  

I Ben Khemis  C Audet  R Fournier  & J de la Noüe 《Aquaculture Research》2003,34(6):445-452

Like most small marine fish larvae, the stomachs of winter flounder Pseudopleuronectes americanus are undeveloped at first feeding and have relatively reduced digestive capacity. This work was undertaken to test whether larvae at the onset of stomach differentiation (larval size about 5.5 mm) could be early weaned onto a commercial microencapsulated diet. We assessed the effect of early weaning by first comparing growth performance (standard length, total protein content and age at metamorphosis) of larvae fed enriched live prey from first feeding to a size of 5.5 mm and then reared on three different feeding regimes until metamorphosis: (1) live prey (LP) as a control group; (2) mixed feeding of live prey and microencapsulated diet (LP‐ME); (3) exclusively microencapsulated diet (ME) after fast weaning over 4 days (to a larval size of 6.2 mm). No differences were observed between larval development in the two first groups, which began metamorphosis at 40 days old. The larvae of the third group showed significantly slower growth that resulted in a delay of 4 days in the onset of metamorphosis. Differences in live prey availability between the treatments and the short transition period to allow the larvae to adapt to the new diet were identified as possible contributing factors to the slower growth and to the delay in metamorphosis of early weaned larvae. In a second experiment, the transitional weaning period was increased until the larvae were 6.6 mm in length. Weaning at that size resulted in no slowing of growth or delay in metamorphosis, suggesting that the feeding schedule was adequate.  相似文献   

The diving behaviour of little penguins in Western Australia predisposes them to risk of injury by watercraft     

Belinda Cannell  Yan Ropert‐Coudert  Ben Radford  Akiko Kato 《水产资源保护:海洋与淡水生态系统》2020,30(3):461-474

1. The most western little penguin colony globally, and the most northern in Western Australia (WA) is found on Penguin Island, WA. The penguins use coastal bays that are also used extensively by recreational watercraft. These penguins have been found to either dive predominantly to shallow depths of 1–5 m or to depths >8 m. It is thus hypothesized that (a) both the shallow and deeper diving penguins can potentially be disturbed or injured by these watercraft but that the risk will differ between the two diving strategies, and (b) that risk of injury for both is greater during the summer and autumn, when people are more likely to use watercraft.
2. This was tested by attaching data loggers to little penguins during chick rearing and by investigating necropsy records. Diving activity was studied for the very shallow and relatively deeper diving penguins separately, and we considered the penguins were vulnerable to interactions with watercraft when they were within the top 2 m of the water column or at the surface.
3. Shallow‐diving penguins executed >1,200 dives per day, 64% of dives occurred within the top 2 m, and they were vulnerable for approximately two‐thirds of their time at sea. The deeper diving penguins executed fewer dives. Almost half of dives were to ≥10 m, yet they were vulnerable for almost one‐third of their time at sea. Their post‐dive recovery was also longer. Thus, the risk of interaction from watercraft differs depending on the diving behaviour.
4. This study highlights the potential impact to little penguins throughout Australia and New Zealand.

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Quantifying biological nitrogen fixation of agroforestry shrub species using 15N dilution techniques under greenhouse conditions     

G. Issah  A. A. Kimaro  J. Kort  J. D. Knight 《Agroforestry Systems》2014,88(4):607-617

Some land-use systems in Saskatchewan, Canada include the nitrogen-fixing trees buffaloberry (Shepherdia argentea Nutt.), caragana (Caragana arborescens Lam.) and sea buckthorn (Hippophae rhamnoides L.). These species provide various ecological functions such as ameliorating soil moisture, light and temperature but little work has been done quantifying biological nitrogen fixation by these species. Greenhouse experiments were conducted to quantify N₂-fixation using the ¹⁵N natural abundance and the ¹⁵N dilution methods. Buffaloberry failed to form nodules in all but one of the four replicates in the natural abundance experiment. Using the ¹⁵N dilution method, the percentage of N derived from atmosphere (%Ndfa) in the shoot of buffaloberry averaged 64 %. For caragana, the mean  %Ndfa was 59 and 65 % and seabuckthorn was 70 and 73 % measured using the natural abundance and dilution methods, respectively. Because of large variability in biomass production between plants grown in the natural abundance experiment and the dilution experiment, the amounts of N₂ fixed also were very variable. Buffaloberry fixed an average of 0.89 g N m^?2; the average for caragana ranged from 1.14 to 4.12 g N m^?2 and seabuckthorn ranged from 0.85 to 3.77 g N m^?2 in the natural abundance and dilution experiments, respectively. This corresponds to 16 kg N ha^?1 year^?1 for buffaloberry; an average of 15–73 kg N ha^?1 year^?1 in caragana and 11–67 kg N ha^?1 year^?1 in seabuckthorn. The substantial amounts of N₂ fixed by these species indicate that they have the potential to contribute to the overall N balance in land-use systems in which they are included.  相似文献   

Comparison of traditional and environmental DNA survey methods for detecting rare and abundant freshwater fish     

Maxine P. Piggott  Samuel C. Banks  Ben T. Broadhurst  Christopher J. Fulton  Mark Lintermans 《水产资源保护:海洋与淡水生态系统》2021,31(1):173-184

1. Detecting rare species is often a necessity for conservation and management, yet challenging for many field survey methods. Environmental DNA (eDNA) is a highly promising solution that has been shown to outperform many established survey methods.
2. Macquarie perch (Macquaria australasica) is an endangered native species that has declined significantly in range and abundance. Detection of M. australasica was compared with an abundant alien fish species (Oncorhynchus mykiss) using eDNA and three conventional survey methods: gill nets, electrofishing and fyke nets.
3. eDNA occupancy estimates for both fish species were compared using four different models to investigate what effect these differences have on false positives and false negatives for the rare and common fish species. These models used unadjusted eDNA detections in water samples, eDNA detections that have been screened using a limit of detection method to remove potential false positives, eDNA data supplemented with a second survey method, or eDNA data augmented with sequencing of positive polymerase chain reaction replicates.
4. eDNA surveying as a single detection method was found to be more efficient and sensitive compared with each capture method separately and combined. Occupancy estimates for the common and rare species did not vary significantly between the four site occupancy-detection models, suggesting that supplementary data may not have as much effect on occupancy estimates compared with other approaches such as temporal or spatial sampling.
5. We conclude that eDNA outperforms the three established survey methods for both a rare and common freshwater fish species. Although there was no significant effect of augmenting eDNA survey methods with other survey data, additional data may improve confidence in detection, and provide confirmatory evidence for unexpected or new detections of a species.

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Salinity tolerance during early development of threatened Murray hardyhead (Craterocephalus fluviatilis) to guide environmental watering     

Daniel J. Stoessel  Peter S. Fairbrother  Ben G. Fanson  Scott M.C. Raymond  Tarmo A. Raadik  Michael D. Nicol  Lauren A. Johnson 《水产资源保护:海洋与淡水生态系统》2020,30(1):173-182

1. The worldwide reduction in wetlands has led to the large‐scale decline of wetland‐dependent species. In Australia, to redress some of the decline, partial restoration of the hydrology of a small number of wetlands has been attempted using allocations of environmental water.
2. A common goal of the watering is the maintenance and enhancement of native fish communities, which historically have included populations of the salt tolerant Murray hardyhead (Craterocephalus fluviatilis), a small, short‐lived fish, endemic to the lower Murray–Darling Basin.
3. Despite the addition of environmental water to several sites at which the species is known to persist, populations continue to decline. This decline is, at least in part, suspected to be a consequence of salinities that conflict with the breeding ecology and survival of early life stages.
4. Here the effect of salinity on egg hatch rate and the upper salinity tolerance of larval and juvenile Murray hardyhead was determined under laboratory conditions. It was found that eggs were vulnerable to elevated salinities, whereas juveniles were capable of tolerating salinities up to 105 ppt.
5. Based on the results of the experiment, brackish wetlands managed for Murray hardyhead should be maintained, where possible, between 12 and 45 ppt. Such a salinity regime will necessitate less intensive management of salinity, and a reduced volume of environmental water, providing both environmental and fiscal benefits. The research highlights the benefits of investment in targeted research.

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The effect of artificial rearing on the growth of foals   总被引：1，自引：0，他引：1  

D A Knight  W J Tyznik 《Journal of animal science》1985,60(1):1-5

Fourteen Quarter Horse foals were used to evaluate the effects of artificial rearing on growth. Seven foals were removed from their dams at 3 d of age and fed a reconstituted 26% crude protein (CP) milk replacer free choice for 1 mo, at which time ad libitum solid feeding began. Controls were weaned from their dams at 2 mo of age and fed a 21% CP concentrate ad libitum until the end of the trial. Variables measured during the 26-wk trial were live body weight, height at the withers and length of body from point of shoulder to point of hip. No significant differences were found between the two groups, except during wk 8 where 2-mo weaned foals were slightly heavier (P less than .10). Average daily gains for artificially reared and 2-mo weaned foals were .95 and .98 kg, respectively.  相似文献   

Efficacy of inotropic support of the failing heart     

D H Knight 《Veterinary Clinics of North America: Small Animal Practice》1991,21(5):879-904

The clinical literature on the subject of inotropic therapy of heart failure, particularly use of digitalis glycosides, is full of contradictions. Most of this disparity can be accounted for if not reconciled by taking the methodology of the clinical trials into consideration. Because drug interventions may produce subtle effects requiring a subjective determination, the questions being asked in these studies cannot be answered without removing as many sources of bias as possible from the patient management and data analysis. If a study has not been adequately randomized, double-blinded, and placebo-controlled, the clinical findings will be inconclusive at best. Systolic myocardial dysfunction plays a pivotal role in the pathogenesis of CHF in many patients and is a prerequisite for the use of cardiotonic drugs. Although the clinical signs of heart failure may be relieved initially by diuretics and vasodilators, compensation may require the addition of a positive inotrope, particularly in advanced cases. In veterinary medicine, the choice of positive inotrope is limited to digoxin, digitoxin, dobutamine, or amrinone. Digoxin possesses superior pharmacokinetics and is the cardiac glycoside of choice for use in the dog. Dobutamine and amrinone are more potent inotropes, but since they must be administered by continuous intravenous infusion, their use is limited to critical care therapy. At the present time, only digoxin can be administered orally for sustained long-term maintenance therapy. Milrinone, a more potent derivative of amrinone, also offers this option, but it has not been available since its brief trial debut as an investigational drug. None of the nonglycoside alternatives couples the benefits of positive inotropic and negative chronotropic effects. Consequently, digoxin remains the mainstay for chronic inotropic support of the heart. Atrial fibrillation with a rapid ventricular response rate is the prime indication for digoxin. In the last few years, evidence from methodologically sound clinical trials on humans has also restored faith in the efficacy of digoxin for treating heart failure in patients with normal sinus rhythm. From these studies, the profile of a digitalis responsive heart failure patient has emerged. Digoxin is most likely to be efficacious when heart failure is associated with chronic, severe ventricular systolic dysfunction, which has resulted in ventricular dilatation. The most reliable clinical marker is the presence of a third heart sound (gallop rhythm). Although the patients in the worst heart failure generally have the shortest survival time, they may also have the most dramatic short-term clinical benefit. However, once cardiac reserve is exhausted in the terminal stages of failure, cardiotonic stimulation ceases to be effective.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献