Le cycle des Nostoc des genres Peltigera et Collema en cultures in vitro et dans le thalle lichénique

1987 ◽  
Vol 65 (7) ◽  
pp. 1468-1477 ◽  
Author(s):  
Jean-Claude Boissière ◽  
Marie-Claude Boissière ◽  
Patrick Champion-Arnaud ◽  
Richard Lallemant ◽  
Jean Wagner
Keyword(s):  
Nostoc Punctiforme ◽  
Biological Cycle ◽  
Nostoc Commune ◽  
Free Living ◽  
Lichen Thallus ◽  
Living Species ◽  
Peltigera Canina

The isolation and culture of Nostoc symbionts of four Peltigera and of Collema tenax has revealed the presence of a biological cycle. Our observations, taken in conjunction with those of other authors on free-living species, suggest that the photosymbiont of Peltigera canina, P. rufescens, P. horizontalis, and P. spuria is Nostoc punctiforme (Kütz.) Hariot, that of Collema tenax is Nostoc commune Vauch. In the lichen thallus, Nostoc is at the stage called "punctiforme." This stage stays stable as long as the thallus is undamaged. If wounding occurs, the opening of the polysaccharide sheath of the trichomes causes motile hormogonia to escape. These, in nature, colonize the squamuliform isidia of Peltigera praetextata and, in culture, they allow isolation of Nostoc strains from the lichens studied.

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.

scholarly journals Misinformation tactics protect rare birds from problem predators

2021 ◽  
Vol 7 (11) ◽  
pp. eabe4164
Author(s):  
Grant L. Norbury ◽  
Catherine J. Price ◽  
M. Cecilia Latham ◽  
Samantha J. Brown ◽  
A. David M. Latham ◽  
...  
Keyword(s):  
Decision Making ◽  
Threatened Species ◽  
Prey Availability ◽  
Free Living ◽  
Bird Populations ◽  
New Information ◽  
Mammalian Predators ◽  
Decision Making Processes ◽  
Living Species ◽  
Information Reliability

Efficient decision-making integrates previous experience with new information. Tactical use of misinformation can alter choice in humans. Whether misinformation affects decision-making in other free-living species, including problem species, is unknown. Here, we show that sensory misinformation tactics can reduce the impacts of predators on vulnerable bird populations as effectively as lethal control. We repeatedly exposed invasive mammalian predators to unprofitable bird odors for 5 weeks before native shorebirds arrived for nesting and for 8 weeks thereafter. Chick production increased 1.7-fold at odor-treated sites over 25 to 35 days, with doubled or tripled odds of successful hatching, resulting in a 127% increase in modeled population size in 25 years. We demonstrate that decision-making processes that respond to changes in information reliability are vulnerable to tactical manipulation by misinformation. Altering perceptions of prey availability offers an innovative, nonlethal approach to managing problem predators and improving conservation outcomes for threatened species.

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.

scholarly journals Draft Genome Sequence of Piscirickettsia litoralis , Isolated from Seawater

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Xuehua Wan ◽  
Alex J. Lee ◽  
Shaobin Hou ◽  
Blake Ushijima ◽  
Yen P. Nguyen ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Salmonid Fish ◽  
Draft Genome Sequence ◽  
Free Living ◽  
Living Species

One species of Piscirickettsia , a pathogen of salmonid fish, has been described. The genome sequence of a putative second and free-living species may provide insights into the evolution of pathogenicity in the genus.

In vitro shock response to different stressors in free living and pathogenic Acanthamoeba

2000 ◽  
Vol 30 (7) ◽  
pp. 829-835 ◽  
Author(s):  
J. Pérez-Serrano ◽  
J. Martı́nez ◽  
B. Pérez ◽  
W.E. Bernadina ◽  
F. Rodrı́guez-Caabeiro
Keyword(s):  
Free Living ◽  
Shock Response
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