In vitro nutritional requirements of Nippostrongylus brasiliensis—I. Effects of sterols, sterol derivatives and heme compounds on the free-living stages

1972 ◽  
Vol 43 (3) ◽  
pp. 487-501 ◽  
Author(s):  
R.I. Bolla ◽  
P.P. Weinstein ◽  
C. Lou
Keyword(s):  
Nutritional Requirements ◽  
Nippostrongylus Brasiliensis ◽  
Free Living

The relevance of in vitro anthelmintic screening tests employing the free-living stages of trichostrongylid nematodes

1984 ◽  
Vol 58 (2) ◽  
pp. 107-112 ◽  
Author(s):  
O.F. Ibarra ◽  
D.C. Jenkings
Keyword(s):  
Broad Spectrum ◽  
Haemonchus Contortus ◽  
Screening Tests ◽  
Nippostrongylus Brasiliensis ◽  
Good Activity ◽  
Free Living ◽  
Ostertagia Ostertagi ◽  
Nematospiroides Dubius ◽  
Antiparasitic Agents

AbstractThe response of the free-living stages of Nippostrongylus brasiliensis, Nematospiroides dubius, Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia ostertagi to a wide variety of antiparasitic agents in vitro was investigated.All the major broad spectrum veterinary anthelmintics showed good activity against each of these worms with EC30 values varying from about 00002mg/1 for certain benzimidazoles and ivermectin to about 6–5 mg/1 for febantel. Of 22 known narrow spectrum anthelmintics useful only against H. contortus and/or helminths other than trichostrongyles, only 10% showed good activity at concentrations equal to or less than 100mg/1. Further, only one of 15 antiprotozoal agents showed good activity in these tests at the 100mg/1 level.

Nippostrongylus brasiliensis: the effect of mitochondnal inhibitors on life-cycle stages

Parasitology ◽  
1984 ◽  
Vol 88 (1) ◽  
pp. 163-177 ◽  
Author(s):  
M. Fry ◽  
D. C. Jenkins
Keyword(s):  
Life Cycle ◽  
Electron Transport ◽  
Oxidative Phosphorylation ◽  
Adult Worm ◽  
Nippostrongylus Brasiliensis ◽  
Free Living ◽  
Mitochondrial Inhibitors ◽  
Life Cycle Stages ◽  
Transport Inhibitors

SUMMARYThe effects of mitochondrial inhibitors on the in vitro development of Nippostrongylus brasiliensis have been studied in free-living and parasitic life-cycle stages. Mitochondrial inhibitors were chosen as being representative of established electron transport inhibitors and oxidative phosphorylation inhibitors and uncouplers of the classical mammalian respiratory chain. All mitochondrial inhibitors tested were highly effective in killing or retarding development of free-living stages of N. brasiliensis. Free-living stages were particularly susceptible to such inhibitors upon hatching of embryonated eggs to 1st-stage larvae. Concentrations of inhibitors effective against free-living stages were consistent with their level of inhibition against isolated mitochondria from embryonated eggs and 3rd-stage infective larvae. Results suggest an absolute requirement in the development of free-living stages for the mammalian-like respiratory chain and associated oxidative phosphorylation. Electron transport inhibitors were effective in retarding at least the initial development of 4th-stage larvae to adults, but only antimycin A and azide produced a lasting effect leading to worm death. Oxidative phosphorylation inhibitors and uncouplers were ineffective against developing parasitic stages of N. brasiliensis. Experiments on whole-worm respiration indicated that most electron transport inhibitors were able to penetrate the adult worm, but oxidative phosphorylation inhibitors were without effect on whole-worm respiration. Results suggest that the mammalian-like electron transport chain is a necessary requirement to adult N. brasiliensis, but oxidative phosphorylation in the adult worm may not be required for development and survival in vitro although it could be necessary to support the parasite in vivo.

scholarly journals Effect of Gaseous Ozone on Listeria monocytogenes Planktonic Cells and Biofilm: An In Vitro Study

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1484
Author(s):  
Felice Panebianco ◽  
Selene Rubiola ◽  
Francesco Chiesa ◽  
Tiziana Civera ◽  
Pierluigi Aldo Di Ciccio
Keyword(s):  
Listeria Monocytogenes ◽  
In Vitro Study ◽  
Planktonic Cells ◽  
Free Living ◽  
Biofilm Inhibition ◽  
Additional Tool ◽  
Complete Inactivation ◽  
Gaseous Ozone ◽  
Food Borne

Among food-borne pathogens, Listeria monocytogenes continues to pose concerns to food business operators due to its capacity to form biofilm in processing environments. Ozone may be an eco-friendly technology to control microbial contaminations, but data concerning its effect on Listeria monocytogenes biofilm are still limited. In this study, the effect of gaseous ozone at 50 ppm on planktonic cells and biofilm of reference and food-related Listeria monocytogenes strains was evaluated. Ozone caused a reduction in microbial loads of 3.7 ± 0.4 and 3.9 ± 0.4 Log10 CFU/mL after 10 and 30 min, respectively. A complete inactivation of planktonic cells after 6 h of treatment was observed. Biofilm inhibition and eradication treatments (50 ppm, 6 h) resulted in a significant decrease of the biofilm biomass for 59% of the strains tested, whilst a slight dampening of live cell loads in the biofilm state was observed. In conclusion, gaseous ozone is not sufficient to completely counteract Listeria monocytogenes biofilm, but it may be useful as an additional tool to contrast Listeria monocytogenes free-living cells and to improve the existing sanitization procedures in food processing environments.

Studies on the aggregation behaviour of Nippostrongylus brasiliensis

Parasitology ◽  
1971 ◽  
Vol 63 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Thomas J. W. Alphey
Keyword(s):  
Research Council ◽  
Sexual Attraction ◽  
Scientific Research ◽  
Nippostrongylus Brasiliensis ◽  
T Tube ◽  
Aggregation Behaviour ◽  
Choice Chamber

Two behaviour patterns which could bring about clumping in N. brasiliensis, sexual attraction and thigmokinesis, were investigated. A T-tube choice-chamber to facilitate an in vitro study of sexual attraction is described. A method for studying aggregation is also outlined. Male N. brasiliensis were shown to be attracted to female worms, positive sexual attraction. Both sexes were shown to exhibit strong thigmokinetic responses, and possible functions of such behaviour are discussed.I am grateful to Professors J. Brough and D. Bellamy for providing the facilities during the course of this study. I should also like to thank Dr E.. A. Hammond for his supervision, help and criticism throughout the project. This work was carried out during the tenure of a Scientific Research Council Studentship.

scholarly journals Detection of Protozoan Hosts for Legionella pneumophila in Engineered Water Systems by Using a Biofilm Batch Test

2010 ◽  
Vol 76 (21) ◽  
pp. 7144-7153 ◽  
Author(s):  
Rinske M. Valster ◽  
Bart A. Wullings ◽  
Dick van der Kooij
Keyword(s):  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Batch Test ◽  
Free Living ◽  
Water Types ◽  
Operational Taxonomic Units ◽  
Hartmannella Vermiformis

ABSTRACT Legionella pneumophila proliferates in aquatic habitats within free-living protozoa, 17 species of which have been identified as hosts by using in vitro experiments. The present study aimed at identifying protozoan hosts for L. pneumophila by using a biofilm batch test (BBT). Samples (600 ml) collected from 21 engineered freshwater systems, with added polyethylene cylinders to promote biofilm formation, were inoculated with L. pneumophila and subsequently incubated at 37°C for 20 days. Growth of L. pneumophila was observed in 16 of 18 water types when the host protozoan Hartmannella vermiformis was added. Twelve of the tested water types supported growth of L. pneumophila or indigenous Legionella anisa without added H. vermiformis. In 12 of 19 BBT flasks H. vermiformis was indicated as a host, based on the ratio between maximum concentrations of L. pneumophila and H. vermiformis, determined with quantitative PCR (Q-PCR), and the composition of clone libraries of partial 18S rRNA gene fragments. Analyses of 609 eukaryotic clones from the BBTs revealed that 68 operational taxonomic units (OTUs) showed the highest similarity to free-living protozoa. Forty percent of the sequences clustering with protozoa showed ≥99.5% similarity to H. vermiformis. None of the other protozoa serving as hosts in in vitro studies were detected in the BBTs. In several tests with growth of L. pneumophila, the protozoa Diphylleia rotans, Echinamoeba thermarum, and Neoparamoeba sp. were identified as candidate hosts. In vitro studies are needed to confirm their role as hosts for L. pneumophila. Unidentified protozoa were implicated as hosts for uncultured Legionella spp. grown in BBT flasks at 15°C.

scholarly journals Control of bovine tick [Rhipicephalus (Boophilus) microplus] with Brunfelsia uniflora leaf extract

2019 ◽  
pp. 903-910
Author(s):  
Elaine Yae Yamashita Sugauara ◽  
ElisângelaYumi Sugauara ◽  
Rosangela Rumi Sugauara ◽  
Wanessa de Campos Bortolucci ◽  
Herika Line Marko de Oliveira ◽  
...  
Keyword(s):  
Ethyl Ester ◽  
Leaf Extract ◽  
Acid Ethyl Ester ◽  
Acaricidal Activity ◽  
Boophilus Microplus ◽  
Ex Situ ◽  
In Vitro Tests ◽  
Free Living ◽  
Crude Leaf Extract

Bovine tick has caused losses in livestock production profitability in Brazil. However, tick control has caused resistance of these ectoparasites against utilized acaricides. Alternative tick controls have been utilizing plants as sources of effective botanical acaricides. Brunfelsia uniflora is a Brazilian plant with antimicrobial and antioxidant activity; however, there are no reports on its acaricidal activity. Therefore, this study aimed to evaluate the chemical composition of B. uniflora leaf ethanolic extract and its efficiency to control bovine tick in vitro and free-living stage ex situ. The crude leaf extract was analyzed by gas chromatographer coupled to mass spectrometer (GC-MS) with identification of 17 compounds. The major compounds were phytol (22.96%), 9,12,15-octadecatrienoic acid, ethyl ester (Z,Z,Z) (21.18%), hexadecanoic acid, ethyl ester (12.74%) and vitamin E (8.77%). The crude extract presented acaricidal activity in vitro against ingurgitated adult females, larvae and eggs of bovine tick. The LC99.9 for larvae was 103.21 mg mL-1 in in vitro tests and was 100% efficient for ex situ larva test (free-living stage). B. uniflora leaf extract is an alternative for the control of the bovine tick cycle, mainly in the free-living stage (non-parasitic stage) under field conditions.

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