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.

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.

Lymnaea glabra: progressive increase in susceptibility to Fasciola hepatica through successive generations of experimentally infected snails

2014 ◽  
Vol 89 (4) ◽  
pp. 398-403 ◽  
Author(s):  
D. Rondelaud ◽  
F.F. Djuikwo Teukeng ◽  
P. Vignoles ◽  
G. Dreyfuss
Keyword(s):  
Fasciola Hepatica ◽  
Progressive Increase ◽  
Parasite Infection ◽  
Snail Infection ◽  
Cattle Breeding ◽  
Galba Truncatula ◽  
Successive Generations ◽  
Breeding Farms ◽  
Two Populations ◽  
Over Time

AbstractExperimental infections of Lymnaea glabra (two populations) with Fasciola hepatica were carried out during seven successive snail generations, to determine if prevalence and intensity of snail infection increased over time through descendants of snails already infected with F. hepatica. Controls were descendants coming from uninfected parents and infected according to the same protocol. No larval forms were found in the bodies of control snails coming from uninfected parents. In contrast, prevalence and intensity of F. hepatica infection in snails originating from infected parents progressively increased from the F2 or F3 to the F6 generation of L. glabra. In another experiment carried out with the F7 generations of L. glabra and a single generation of Galba truncatula (as controls), the prevalence of F. hepatica infection and the total number of cercariae were lower in L. glabra (without significant differences between both populations). If the number of cercariae shed by infected snails was compared to overall cercarial production noted in snails containing cercariae but dying without emission, the percentage was greater in G. truncatula (69% instead of 52–54% in L. glabra). Even if most characteristics of F. hepatica infection were lower in L. glabra, prevalence and intensity of parasite infection increased with snail generation when tested snails came from infected parents. This mode of snail infection with F. hepatica suggests an explanation for cases of fasciolosis occurring in cattle-breeding farms where paramphistomosis is lacking and G. truncatula is absent.

Characteristics of Fasciola hepatica infections in Galba truncatula originating from riverbank populations

2010 ◽  
Vol 85 (1) ◽  
pp. 28-32 ◽  
Author(s):  
P. Vignoles ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Fasciola Hepatica ◽  
Acid Soil ◽  
Spring Water ◽  
The Other ◽  
Breeding Method ◽  
Galba Truncatula ◽  
Post Exposure ◽  
Petri Dishes

AbstractFour geographical strains of Galba truncatula living on riverbanks (the first on a sedimentary soil and the other three on an acid soil) were subjected to bimiracidial exposures with Fasciola hepatica to study their aptitude for cercarial shedding and to count metacercariae in snails dissected at day 42 post-exposure. All snails were reared in 14-cm Petri dishes at 24°C, with the same spring water (60–73 mg/l of Ca2+) and the same diet (grass and lettuce leaves). Metacercariae of F. hepatica were noted in the four populations after a cercarial shedding or after snail dissection. However, in spite of the breeding method used, the characteristics of snail infections varied with the origin of each geographical strain. For example, the shell heights of infected snails at day 42 were close to those found for the corresponding adults in the field (6.8–8.0 mm for the population living on the sedimentary soil, but only 4.6–5.5 mm for another strain originating from the acid soil). This variability may be explained by assuming that the diet of these riverbank G. truncatula would be different from that of snails living in swampy meadows. However, another hypothesis based on the influence of snail habitat on the characteristics of snail life cannot be excluded.

Calicophoron daubneyiandFasciola hepatica: characteristics of natural and experimental co-infections of these digeneans in the snailLymnaea glabra

2016 ◽  
Vol 91 (1) ◽  
pp. 1-6 ◽  
Author(s):  
P. Vignoles ◽  
A. Titi ◽  
A. Mekroud ◽  
D. Rondelaud ◽  
G. Dreyfuss
Keyword(s):  
Retrospective Study ◽  
Fasciola Hepatica ◽  
Shell Height ◽  
The Other ◽  
Patent Period ◽  
Galba Truncatula ◽  
Experimental Infections ◽  
Calicophoron Daubneyi

AbstractA retrospective study on differentLymnaea glabrasamples collected from central France between 1993 and 2010 was carried out to determine the prevalence of natural co-infections withCalicophoron daubneyiandFasciola hepatica, and to specify the composition of redial burdens. Experimental infections ofL. glabraperformed during the same period of time were also analysed to study metacercarial production of each digenean in co-infected snails. Controls were naturally or experimentally co-infectedGalba truncatula. In natural co-infections, prevalence was 0.7% inL. glabra(186/25,128) and 0.4% inG. truncatula(137/31,345). Low redial burdens were found in these snails, withF. hepaticarediae significantly more numerous inL. glabrathan inG. truncatula(7.5 per snail instead of 5.2). In contrast, the total numbers ofC. daubneyirediae in both lymnaeids were close to each other (4.3 and 3.0 rediae, respectively). In experimentally co-infected groups, prevalence was greater inG. truncatulathan in the other lymnaeid (6.3% instead of 3.0%). Significantly shorter patent periods and lower metacercarial production for each digenean were noted inL. glabrathan inG. truncatula.However, in both lymnaeids, the two types of cercariae were released during the same shedding waves and several peaks during the patent period were synchronous. In spite of a greater shell height forL. glabra, metacercarial production of both digeneans in co-infected snails was lower than that inG. truncatula, thus indicating a still incomplete adaptation between these FrenchL. glabraand both parasites.

Determination of the minimum number of technological bases of a part

2020 ◽  
pp. 73-75
Author(s):  
B.M. Bazrov ◽  
T.M. Gaynutdinov
Keyword(s):  
Cost Price ◽  
Labor Input ◽  
Part Surface ◽  
Technological Base ◽  
Size Accuracy ◽  
Minimum Number ◽  
The Cost ◽  
Input Cost ◽  
Selection Of

The selection of technological bases is considered before the choice of the type of billet and the development of the route of the technological process. A technique is proposed for selecting the minimum number of sets of technological bases according to the criterion of equality in the cost price of manufacturing the part according to the principle of unity and combination of bases at this stage. Keywords: part, surface, coordinating size, accuracy, design and technological base, labor input, cost price. [email protected]

An improved method of calculating the cost price of the product

1972 ◽  
Vol 3 (2) ◽  
pp. 191-194
Author(s):  
N. D. Novikova ◽  
E. N. Arnoldova ◽  
N. P. Bogatova ◽  
Z. V. Bobrova
Keyword(s):  
Cost Price ◽  
Improved Method ◽  
The Cost

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.

Study on the price of water rights trading between agriculture and industry based on emergy theory

2019 ◽  
Vol 19 (7) ◽  
pp. 2044-2053
Author(s):  
Wenge Zhang ◽  
Li Tan ◽  
Huijuan Yin ◽  
Xinwei Guo
Keyword(s):  
Water Resources ◽  
Water Conservation ◽  
Economic Value ◽  
Water Rights ◽  
Active Role ◽  
Cost Price ◽  
Pricing Model ◽  
Stage Of Development ◽  
Emergy Theory ◽  
The Cost

Abstract A water rights trading scheme in China is currently in its initial stage of development, but is without a complete pricing mechanism. This paper proposes a pricing model for transfers of water rights from agriculture to industry in water-deficient areas of China. Both the cost price and the earnings price are considered and incorporated into the model. The cost price includes construction costs, operation and maintenance costs, renewal and reconstruction costs, and economic compensation for ecological damage. The earnings price is calculated according to a reasonable return coefficient and the difference in economic value of the water resources to the buyer and seller. The value of water resources was estimated based on emergy theory in accordance with the principle of mutual benefits equilibrium. This pricing model is then applied to the transfer of surplus water rights arising from agricultural water conservation schemes to industrial uses in the Southbank Ordos Irrigation Zone of the Inner Mongolia Autonomous Region. The results indicate that this pricing model could provide technical support to the scientific and reasonable pricing of water rights transactions in water-deficient areas and that it could play an active role in promoting the healthy development of future water markets.

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.

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