The experimental production of Fasciola hepatica metacercariae from three aquatic populations of Galba truncatula

2003 ◽  
Vol 77 (3) ◽  
pp. 275-277 ◽  
Author(s):  
P. Vignoles ◽  
L. Favennec ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Fasciola Hepatica ◽  
Commercial Production ◽  
Experimental Production ◽  
Romaine Lettuce ◽  
Experimental Conditions ◽  
Massif Central ◽  
Galba Truncatula ◽  
Laboratory Investigations ◽  
The Cost ◽  
Daily Time

AbstractLaboratory investigations on three aquatic populations of Galba truncatula, originating from the Peruvian Altiplano and French Massif Central, were carried out during three successive snail generations to determine if these populations might be successfully used for the metacercarial production of Fasciola hepatica under experimental conditions. High numbers of surviving snails at day 30 post-exposure (>70%), high prevalences of F. hepatica infections (>60%), and prolonged productions of cercariae for a mean period of 35 to 47 days were observed in the three populations, whatever the snail generation. In the Peruvian population, metacercariae of F. hepatica significantly decreased in numbers from a mean of 251 in the parent snails to 124 per snail in the F2 generation, whereas no significant variation was observed in the two French populations. As these aquatic snails rarely emerged out of water, the use of these populations for the commercial production of F. hepatica metacercariae was of great interest, because the daily time spent watching the breeding boxes of snails was clearly shorter, thereby reducing the cost of producing metacercariae compared with using amphibious snails reared with romaine lettuce.

The production of mammalian trematode infective stages by the snail Galba truncatula

2012 ◽  
Vol 88 (1) ◽  
pp. 105-111 ◽  
Author(s):  
D. Rondelaud ◽  
R. Mouzet ◽  
P. Vignoles ◽  
G. Dreyfuss ◽  
J. Cabaret
Keyword(s):  
Fasciola Hepatica ◽  
Commercial Production ◽  
Cost Price ◽  
Patent Period ◽  
Snail Infection ◽  
Galba Truncatula ◽  
Pasteur Pipette ◽  
Petri Dishes ◽  
The Cost

AbstractSeveral experiments on the breeding of trematode-infected Galba truncatula for obtaining and packaging Fasciola hepatica and Paramphistomum daubneyi metacercariae were carried out to determine the more convenient methods to use for commercial production of these infective stages. Compared to the breeding of infected snails in aquaterraria, the use of 14-cm Petri dishes allowed a greater prevalence of snail infection and a higher number of metacercariae. The production of these larvae was still 2.3–3.4 times greater if infected snails were dissected during the patent period. The aspiration of these metacercariae at the extremity of a Pasteur pipette significantly shortens the time necessary for their transfer from Petri dishes to Eppendorf tubes. Using 14-cm Petri dishes, snail dissection and metacercarial aspiration for their transfer strongly reduce the cost price for metacercarial production of the trematodes Fasciola hepatica and Paramphistomum daubneyi.

scholarly journals More for less: predicting and maximizing genomic variant discovery via Bayesian nonparametrics

Biometrika ◽  
2021 ◽  
Author(s):  
Lorenzo Masoero ◽  
Federico Camerlenghi ◽  
Stefano Favaro ◽  
Tamara Broderick
Keyword(s):  
Optimal Allocation ◽  
Bayesian Nonparametrics ◽  
Allocation Of Resources ◽  
Experimental Conditions ◽  
Follow Up Study ◽  
Variant Discovery ◽  
Fixed Budget ◽  
The Cost ◽  
Genomic Variant

Abstract While the cost of sequencing genomes has decreased dramatically in recent years, this expense often remains non-trivial. Under a fixed budget, scientists face a natural trade-off between quantity and quality: spending resources to sequence a greater number of genomes or spending resources to sequence genomes with increased accuracy. Our goal is to find the optimal allocation of resources between quantity and quality. Optimizing resource allocation promises to reveal as many new variations in the genome as possible. In this paper, we introduce a Bayesian nonparametric methodology to predict the number of new variants in a follow-up study based on a pilot study. When experimental conditions are kept constant between the pilot and follow-up, we find that our prediction is competitive with the best existing methods. Unlike current methods, though, our new method allows practitioners to change experimental conditions between the pilot and the follow-up. We demonstrate how this distinction allows our method to be used for more realistic predictions and for optimal allocation of a fixed budget between quality and quantity.

scholarly journals Screening of apple genotypes with the columnar growth habit using control markers

2020 ◽  
Vol 25 ◽  
pp. 03007
Author(s):  
Natalia Saveleva ◽  
Alexander Lyzhin ◽  
Andrey Yushkov ◽  
Alexander Zemisov ◽  
Nadezhda Borzykh
Keyword(s):  
Growth Habit ◽  
Early Stage ◽  
Research Process ◽  
Commercial Production ◽  
Juvenile Stage ◽  
Juvenile Period ◽  
Columnar Growth ◽  
Apple Cultivars ◽  
The Cost ◽  
Modern Breeding

One of the approaches to intensify horticulture is to introduce cultivars with an unusual canopy into commercial production. Such plants can be columnar Apple trees. In modern breeding, there is a trend to create cultivars with a compact canopy. In such orchards, it is reduced to a minimum the cost for pruning, harvesting, and protection against pest and disease, which are the main expenses in apple orchards with a traditional canopy. The use of molecular markers linked to columnar growth habit allows us to identify a physiological sign at an early stage of growth: in the juvenile period. The assessment of apple cultivars and hybrids was carried out at the I. V. Michurin Federal Scientific Centre in 2015-2018. Four markers were used in the research: Mdo. chr 10.12, C18470-25831, 29f1, and jwlr to identify plants with the columnar growth habit gene (Co). The use of various DNA markers made it possible to establish that not all of them are well linked to the Co gene. In the research process, primers were identified for markers 29f1 and jwlr, which reliably allowed us to identify plants with columnar growth habit at the juvenile stage, which will significantly reduce the breeding process.

A review of gasification of bio-oil for gas production

2019 ◽  
Vol 3 (7) ◽  
pp. 1600-1622 ◽  
Author(s):  
Ji-Lu Zheng ◽  
Ya-Hong Zhu ◽  
Ming-Qiang Zhu ◽  
Kang Kang ◽  
Run-Cang Sun
Keyword(s):  
Large Scale ◽  
Cost Effective ◽  
Gas Production ◽  
Commercial Production ◽  
Advanced Fuels ◽  
Bio Oil ◽  
Effective Transport ◽  
The Cost

The commercial production of advanced fuels based on bio-oil gasification could be promising because the cost-effective transport of bio-oil could promote large-scale implementation of this biomass technology.

Preenrichment Conditions for Effective Recovery of Salmonella in Foods and Feed Ingredients

1979 ◽  
Vol 42 (2) ◽  
pp. 153-157 ◽  
Author(s):  
J. Y. D'AOUST ◽  
C. MAISHMENT
Keyword(s):  
Brilliant Green ◽  
False Negative ◽  
Food Samples ◽  
Contamination Level ◽  
Experimental Conditions ◽  
Feed Ingredients ◽  
Selective Enrichment ◽  
Negative Results ◽  
False Negative Results ◽  
The Cost

The efficacy of Clausen, EE, Eugon, GN, Tergitol 7, lactose and nutrient broths as Salmonella preenrichment media was evaluated using 165 food samples with an incident contamination level ranging from 1.5 to 460 salmonellae/100 g. Replicate food samples (100 g) were preenriched in each of seven media (900 ml) for 6 h and 24 h at 35 C; various amounts (10, 1.0 and 0.1 ml) of preenriched cultures were selectively enriched in tetrathionate brilliant green (43 C) and selenite cystine (35 C) broths and plated on bismuth sulfite and brilliant green sulfa agars. Short (6 h) and 24-h preenrichment conditions resulted in 26 (16%) and 8 (5%) false negative results, respectively. Recovery of Salmonella from 6-h but not 24-h preenrichment cultures also varied directly with the portion of culture inoculated into selective enrichment broths. None of the preenrichment media tested performed satisfactorily at 6 h of incubation where levels of recovery ranged from 32 to 62%; at 24 h, good recovery was obtained with all media (95 to 100%) except EE broth (74%). The incidence of competitive flora was significantly higher on selenite + brilliant green sulfa than on tetrathionate + bismuth sulfite; transfer volumes (10 and 1.0 ml) and preenrichment media did not contribute significantly to the presence of non-salmonellae on plating media. Characteristics of preenrichment media were found to be less critical than preenrichment incubation time for effective recovery of Salmonella in foods and feed ingredients. The use of 1.0- rather than 10-ml preenrichment transfer volume is indicated because it proved to be completely reliable under our experimental conditions and reduced the cost of analyses.

scholarly journals Intermediate snail hosts of French Fasciola hepatica: Lymnaea neotropica and Lymnaea viatrix are better hosts than local Galba truncatula

2012 ◽  
Vol 111 (5) ◽  
pp. 2011-2016 ◽  
Author(s):  
R. Sanabria ◽  
R. Mouzet ◽  
B. Courtioux ◽  
P. Vignoles ◽  
D. Rondelaud ◽  
...  
Keyword(s):  
Fasciola Hepatica ◽  
Galba Truncatula

Influence of body weight, swimming characteristics, and water temperature on the cost of swimming in brook trout (Salvelinus fontinalis)

2000 ◽  
Vol 57 (7) ◽  
pp. 1482-1488 ◽  
Author(s):  
Ming Tang ◽  
Daniel Boisclair ◽  
Chantal Ménard ◽  
John A Downing
Keyword(s):  
Experimental Data ◽  
Water Temperature ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Significant Proportion ◽  
Average Difference ◽  
Fish Swimming ◽  
Experimental Conditions ◽  
Fish Weight ◽  
The Cost

We performed respirometry experiments to estimate the spontaneous swimming costs of brook trout (Salvelinus fontinalis) for 24 combinations of fish weight (3.5, 17, and 32 g), water temperature (4, 12, and 18°C), and respirometer size (27, 54, and 108 L). Fish swimming characteristics were estimated for each experiment using videocamera recordings and image analysis. Under our experimental conditions, average swimming characteristics of fish, such as swimming speed and turning and acceleration rates, varied from 2.5- to 29-fold. Our data, alone or combined with similar published results on brook trout weighing 1 g, indicated that fish weight was the only variable that could explain a statistically significant proportion of the variations of spontaneous swimming costs for that species (r2 = 0.91). Our work confirms, with a wider range of experimental data, that spontaneous swimming costs of fish are 3- to 22-fold (8-fold average difference) more energy demanding than predicted by forced swimming models developed using fish swimming at constant speeds and directions in flumes.

Thermally induced mineral and chemical transformations in calcareous mudstones around a basaltic dyke (Perthus Pass, southern Massif Central, France). Possible implications as a natural analogue of nuclear waste disposal

Clay Minerals ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 213-231 ◽  
Author(s):  
C. Henry ◽  
J.-Y. Boisson ◽  
A. Bouchet ◽  
A. Meunier
Keyword(s):  
Theoretical Calculations ◽  
Heat Diffusion ◽  
Large Temperature ◽  
Chemical Transformations ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Retention Capacity ◽  
Massif Central ◽  
Thermally Induced ◽  
X Ray

AbstractA mixed-layer illite-smectite, illite-rich calcareous mudstone intruded by a basaltic dyke at the Perthus Pass (southern Massif Central, France) allows us to study the transformation of clays subjected to a brief thermal gradient. X-ray diffraction, scanning electron microscopy, electron microprobe and atomic absorption spectroscopy analyses were performed on samples at variable distances from the mudstone-dyke contacts.A roughly similar evolution is seen on both sides of the dyke: quartz, calcite, kaolinite and illite disappear; Ca-silicates, albite and saponite-beidellite form, late meteoric halloysite crystallizes in open fractures.Chemical and mineralogical transformations are related to heat diffusion from the dyke. Theoretical calculations highlight the influence of the dyke orientation. The mineralogical reactions observed in rocks are similar to those observed in experimental conditions. The formation of new swelling phases with a high retention capacity linked to a short duration, large-temperature increase, should constitute a positive process for Repository Performance Assessment.

scholarly journals Differences in the compatibility of infection between the liver flukes Fascioloides magna and Fasciola hepatica in a Colombian population of the snail Galba sp.

2014 ◽  
Vol 89 (6) ◽  
pp. 720-726 ◽  
Author(s):  
G. Dreyfuss ◽  
A.C. Correa ◽  
F.F. Djuikwo-Teukeng ◽  
A. Novobilský ◽  
J. Höglund ◽  
...  
Keyword(s):  
Czech Republic ◽  
Larval Development ◽  
Fasciola Hepatica ◽  
Intermediate Hosts ◽  
The Czech Republic ◽  
Galba Truncatula ◽  
Fascioloides Magna ◽  
Post Exposure ◽  
Experimental Infections ◽  
Liver Flukes

AbstractExperimental infections of Galba sp. (origin, Colombia) with allopatric isolates of Fasciola hepatica from France or Fascioloides magna from the Czech Republic were carried out during five successive snail generations to determine if this lymnaeid might sustain complete larval development of either parasite. In snails exposed to F. hepatica, 7 of 400 snails harboured several rediae and only two snails contained a small number of free cercariae on day 50 post-exposure. In contrast, the intensity of F. magna infection in Galba sp. progressively increased from the F1 to F5 generations. Spontaneous cercarial shedding of F. magna occurred in 7 of 100 Galba sp. belonging to the F5 generation and the number of shed cercariae did not differ significantly from that noted in control Galba truncatula of French origin. Galba sp. from Colombia can be added to the list of potential intermediate hosts for F. magna.

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