Biological control studies: Bacteria associated with moribund Biomphalaria glabrata (Mollusca) in the laboratory

Cheng, Thomas C.

doi:10.1016/0022-2011(86)90049-2

Cited by 10 publications

(6 citation statements)

References 20 publications

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“…Additionally, the use of these molecules for extended periods favoured the selection of resistant snails, making its use in o cial control programs untenable (Andrews et al 1982), condition that reinforces the importance of studies aimed at the development of new technologies related to the control of these hosts. This situation has encouraged the development of alternative control methods, targeting the host snail, involving application of biodegradable substances obtained from plants (Hartmann et al 2011), alone or in association with pathogenic microorganisms such as entomopathogenic nematodes (Tunholi et al 2017a, b), bacteria (Cheng 1986;Singer et al 1997) and fungi (Duarte et al, 2015;Castro et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Susceptibility of embryos of Biomphalaria tenagophila (Mollusca: Gastropoda) to infection by Pochonia chlamydosporia (Ascomycota: Sordariomycetes)

Castro

Martins

Tunholi-Alves

et al. 2022

Preprint

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The trematode Schistosoma mansoni is a heteroxenous parasite, meaning that during its life cycle needs the participation of obligatory intermediate and definitive hosts. The larval development occurs in aquatic molluscs belonging to the Biomphalaria genus, leading to the formation of cercariae, which emerge to infect the final vertebrate host. For this reason, studies for control of the diseases caused by digenetic trematodes often focus on combating the snail hosts. Thus, the objective of this study was to evaluate the susceptibility of Biomphalaria tenagophila embryos to the fungus Pochonia chlamydosporia (isolate Pc-10) under laboratory conditions. Two experimental groups were formed: the control group, consisting of egg masses not exposed to the fungus; and the treated group, in which the snail egg masses were exposed to mycelium of the fungal isolate (Pc-10). At the end of 15 days, the egg masses were evaluated under a stereomicroscope to analyze the hatching of B. tenagophila embryos in both experimental groups. The entire experiment was conducted in duplicate, with five replicates for each repetition (five egg masses/replicate), utilizing a total of 100 egg masses, with 20 to 30 eggs/egg mass. After 15 days of interaction, the exposure to the fungal hyphae bodies significantly impaired the viability of the B. tenagophila eggs, inhibiting the embryogenesis process by 83.7% in relation to the control group. Transmission and scanning electron microscopic images revealed relevant structural alterations in the egg masses exposed to the hyphae action of the fungus, interfering in the development and hatching of the young snails under analysis. These results indicate the susceptibility of B. tenagophila embryos to the fungus P. chlamydosporia (isolate Pc-10) and suggests the potential of Pc-10 to be used in the control of parasitic agents, such as S. mansoni, but in vivo experiments become necessary.

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Section: Introductionmentioning

confidence: 99%

Susceptibility of embryos of Biomphalaria tenagophila (Mollusca: Gastropoda) to infection by Pochonia chlamydosporia (Ascomycota: Sordariomycetes)

Castro

Martins

Tunholi-Alves

et al. 2022

Preprint

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“…In this respect certain species and varieties of bacteria such as Vibrio, Pseudomonas, Citrobacter, Aeromonas, and Bacillus thuringiensis have been tested on some biological aspects of fresh water snails (Ducklow et al 1980 andLarget & Barjac, 1981;Cheng, 1986;Madsen, 1992 , 1999). B. thuringiensis kurstaki was found to have a significant toxic effect on B.alexandrina snails and a concentration of this bacteria as low as 0.08 gm/L water has a considerable reducing effect on egg production of the snail and on its infection with S.mansoni (Gamal et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Effect of Biomphalaria Alexandrina Snails Infected by Bacillus Thuringiensis Kurstaki on Three Successive Generations of Schistosoma Mansoni

El-Bardicy

Tadros

Hafez

2005

Arab Universities Journal of Agricultural Sciences

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The effect of infection of Biomphalaria alexandrina snails with Bacillus thuringiensis kurstaki on various stages of Schistosoma mansoni life cycle was studied for three successive generations. Thus, two groups of snails were exposed to a sublethal concentration of the bacteria (0.08 gm/L water) containing 32000 IU/mg, for one week and to schistosome miracidia. One group was exposed to the miracidia before bacterial infection, while the other group to the miracidia after the bacterial infection. Cercariae produced from each group of snails were used to infect albino mice. The infection of snails and mice with the parasite was repeated for three generations of the parasite. In the first case, data obtained show that the schistosome infection rate of snails was considerably reduced being 60%, 18%, and 66.6% versus 90 % , 92% and 90% in untreated control snails in the three generations of the parasite, respectively. Meanwhile, the mean prepatent period was extended being 29.1  4.3 days, 33  1 days and 38.5  2.5 days versus 27 days in the control group. The number of worms recovered from infected mice showed reduction of 52 %, 78.4% and 58.6%, respectively. In the second case, the infection rate of snails was 40%, 16% and 73.7% for the three successive parasite generations and the prepatent period was 32  1 days, 32  2.3 days and 35  2.8 days, respectively. The reduction percentage of the recovered worms was 34.8, 73.6 and 72.9 in the sccessive generations, respectively. The present results prove that infecting B.alexandrina snails with a sublethal concentration of B. thuringiensis kurstaki bacteria exhibits clear negative effect on the transmission of S. mansoni in three successive generations. So, it could be recommended to use B. thuringiensis kurstaki as a potential biocontrol agent against S. mansoni.

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“…Aseptic procedures were not followed during the cyst isolation procedures. Cheng (1986) identified bacteria associated with moribund specimens of B. glabrata. Citrobacter freundii, a common aquatic species, was associated with 99%, and A. hydrophila, a sometimes pathogenic species, was associated with 66% of the moribund snails.…”

mentioning

confidence: 99%

“…Citrobacter freundii, a common aquatic species, was associated with 99%, and A. hydrophila, a sometimes pathogenic species, was associated with 66% of the moribund snails. Cheng (1986) also isolated Pseudomonas aeruginosa, E. cloacae, E. agglomerans, Flavobacterium The type of hemolysis for the Gram-positive rods isolated is indicated in parentheses ssp., Pseudomonas putida, Klebsiella oxytoca, Pseudomonas sp., Escherichia coli, Vibrio alginoliticus, and Acinetobacter sp. from the snails.…”

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confidence: 99%

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Association of bacteria with metacercarial cysts of Echinostoma caproni

2007

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Echinostoma caproni metacercarial cysts often need to be stored for several months to a year to meet laboratory requirements. This study examined the bacteria associated with encysted metacercariae stored at 4°C. Bacterial assemblages from the kidney-pericardial region of uninfected snails and assemblages from the site of metacercarial infection in Biomphalaria glabrata were determined. Four species of Gram-negative rods were isolated and identified from the stored cysts to species or genus as Pseudomonas sp., Alcaligenes sp., Enterobacter cloacae, and Aeromonas hydrophila. Gram-positive rods were also isolated and included small slender rods (alpha hemolytic), small coccobacilli (gamma hemolytic), and small rods that exhibited gamma hemolysis. Accumulation of these bacteria on the surface of encysted metacercariae probably contributed to a decreased cyst viability of E. caproni.Fried and Huffman (1996) reviewed the biology of the intestinal trematode Echinostoma caproni, a useful digenean species for various areas of research in experimental parasitology. This echinostome is a convenient model for research and teaching because it cycles between the medically important Biomphalaria glabrata snail and laboratory mice. Therefore, all stages of the life cycle are easily and readily available for experimentation.Relatively few studies are available that mention or identify bacteria associated with the surface of metacercarial cysts or the tegument of adult digeneans. Irwin and Fried (1990), using scanning and transmission electron microscopy, noted bacteria associated with the surface of the metacercarial cyst of E. caproni. Nollen and Nadakavukaren (1974) observed rod-shaped bacteria, by scanning electron microscopy, adhering to the tegument of Megalodiscus temperatus adults isolated from naturally infected frogs. Aho et al. (1991) reported three species of Gram-negative bacteria isolated from the tegument of Clinostomum marginatum adults recovered from the mouth of two great blue herons. The bacteria were identified as Achromobacter sp., Edwardsiella tarda, and Enterobacter agglomerans. Li et al. (2006) evaluated morphological changes and infectivity of the encysted metacercariae of Clonorchis sinensis stored in phosphate-buffered saline (PBS) with and without antibiotics for up to 6 months. They reported that metacercariae stored in PBS with antibiotics showed significantly higher survival rates and infectivity than those in PBS without antibiotics.It is often necessary to store E. caproni metacercariae for several months to meet laboratory requirements. It is important to determine the viability and infectivity of cysts after prolonged storage in the laboratory. Because bacteria associated with cysts probably contribute to the eventual loss of cyst viability and infectivity, the purpose of this study was to determine the types of bacteria present during prolonged storage of E. caproni cysts in nonsterile Locke's 1:1 solution.Encysted metacercariae of E. caproni were isolated from the kidney-pericardial region of ...

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Biological control studies: Bacteria associated with moribund Biomphalaria glabrata (Mollusca) in the laboratory

Cited by 10 publications

References 20 publications

Susceptibility of embryos of Biomphalaria tenagophila (Mollusca: Gastropoda) to infection by Pochonia chlamydosporia (Ascomycota: Sordariomycetes)

Susceptibility of embryos of Biomphalaria tenagophila (Mollusca: Gastropoda) to infection by Pochonia chlamydosporia (Ascomycota: Sordariomycetes)

Effect of Biomphalaria Alexandrina Snails Infected by Bacillus Thuringiensis Kurstaki on Three Successive Generations of Schistosoma Mansoni

Association of bacteria with metacercarial cysts of Echinostoma caproni

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