scholarly journals Cartography of Free-Living Amoebae in Soil in Guadeloupe (French West Indies) Using DNA Metabarcoding

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 440
Author(s):  
Yann Reynaud ◽  
Célia Ducat ◽  
Antoine Talarmin ◽  
Isabel Marcelino
Keyword(s):  
West Indies ◽  
Hot Springs ◽  
Soil Samples ◽  
Microbial Pathogens ◽  
Potential Threat ◽  
Free Living ◽  
Dna Metabarcoding ◽  
Different Temperatures ◽  
Les Saintes ◽  
Enrichment Step

Free-living amoebae (FLA) are ubiquitous protists. Pathogenic FLA such as N. fowleri can be found in hot springs in Guadeloupe, soil being the origin of this contamination. Herein, we analyzed the diversity and distribution of FLA in soil using a targeted metataxonomic analysis. Soil samples (n = 107) were collected from 40 sites. DNA was extracted directly from soil samples or from FLA cultivated at different temperatures (30, 37 and 44 °C). Metabarcoding studies were then conducted through FLA 18SrDNA amplicons sequencing; amplicon sequence variants (ASV) were extracted from each sample and taxonomy assigned against SILVA database using QIIME2 and SHAMAN pipelines. Vermamoeba were detected in DNA extracted directly from the soil, but to detect other FLA an amoebal enrichment step was necessary. V. vermiformis was by far the most represented species of FLA, being detected throughout the islands. Although Naegleria were mainly found in Basse-Terre region, N. fowleri was also detected in Grand Terre and Les Saintes Islands. Acanthamoeba were mainly found in areas where temperature is approx. 30 °C. Vannella and Vahlkampfia were randomly found in Guadeloupe islands. FLA detected in Guadeloupe include both pathogenic genera and genera that can putatively harbor microbial pathogens, therefore posing a potential threat to human health.

Influence of temperature on life history traits of the free-living, bacterial-feeding nematode Panagrolaimus sp. strain NFS-24

Nematology ◽  
2013 ◽  
Vol 15 (8) ◽  
pp. 939-946 ◽  
Author(s):  
Farhana Ayub ◽  
Olaf Strauch ◽  
Laurent Seychelles ◽  
Ralf-Udo Ehlers
Keyword(s):  
Intrinsic Rate ◽  
Analysis Data ◽  
Natural Increase ◽  
Population Doubling ◽  
Food Density ◽  
Hanging Drop ◽  
Free Living ◽  
Single Male ◽  
Different Temperatures ◽  
Hanging Drop Method

Life cycle analysis data of the free-living, bacterial-feeding Panagrolaimus sp. strain NFS 24-5 were assessed at different temperatures using a hanging drop method with single male and female individuals and a food density of 3 × 109 Escherichia coli cells ml−1. Lifespan at the moment when the first egg was laid was 5.7 days at 21°C and 4 days at 25, 27 and 29°C. The intrinsic rate of natural increase () was 0.53 at 21°C, 0.81 at 25°C, 0.93 at 27°C and 0.81 at 29°C, corresponding to population doubling times () of 1.3, 0.9, 0.7 and 0.9 days, respectively. Over 200 offspring per female were produced at 27°C. All other temperatures yielded fewer offspring. When females were kept without males, the life span was 49 days, whereas the last reproductive female (hanging drop with male individual) died after 16.5 days. These data will contribute to the interpretation of nematode population dynamics recorded in liquid culture.

scholarly journals Predatory activity of Arthrobotrys oligospora and Duddingtonia flagrans on pre-parasitic larval stages of cyathostominae under different constant temperatures

2001 ◽  
Vol 31 (5) ◽  
pp. 839-842 ◽  
Author(s):  
Clóvis de Paula Santos ◽  
Terezinha Padilha ◽  
Maria de Lurdes de Azevedo Rodrigues
Keyword(s):  
Optimum Temperature ◽  
Duddingtonia Flagrans ◽  
Arthrobotrys Oligospora ◽  
Egg Development ◽  
Free Living ◽  
Predatory Activity ◽  
Larval Stages ◽  
Different Temperatures ◽  
Reduction Percentage

The effect of different temperatures on the predatory activity of Arthrobotrys oligospora and Duddingtonia flagrans on the free-living larval stages of cyathostomes were evaluated in an experiment where feces of horses containing the parasites’ eggs were treated with these fungi and incubated under different constant temperatures (10°C, 15°C, 20°C, 25°C and 30°C ). The results indicated that the optimum temperature for egg development was 25°C. At 10°C the number of L3 recovered was practically zero, and at 15°C and 20°C, the percentage of larvae recovered was less than 3% of the total number of eggs per gram of feces. When these cultures subsequently were incubated for an additional period of 14 days at 27°C, they allowed the development of L3. In all the cultures inoculated with fungi a significant reduction in the number of larvae was observed. When incubated at 25°C or 30°C, the fungi caused reductions above 90%, in the number of L3. The samples cultivated at 10°C, 15°C, 20°C, 25°C and 30°C, when incubated for an additional period of 14 days at 27°C the reduction percentage of larvae was above 90% for A. oligospora. However, the same did not occur for D. flagrans. Here a reduction percentage between 47.5% and 41.8% was recorded when the cultures were incubated at 10°C and 20°C, respectively. The two species of fungi tested showed to be efficient in reducing the number of L3 when mixed with equine feces and maintained at the same temperature for the development of larval pre-parasitic stages of cyathostomes.

scholarly journals Changes in Quinone Profiles of Hot Spring Microbial Mats with a Thermal Gradient

1999 ◽  
Vol 65 (1) ◽  
pp. 198-205 ◽  
Author(s):  
Akira Hiraishi ◽  
Taichi Umezawa ◽  
Hiroyuki Yamamoto ◽  
Kenji Kato ◽  
Yonosuke Maki
Keyword(s):  
Thermal Gradient ◽  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Thermal Gradients ◽  
Cyanobacterial Mats ◽  
Dissimilarity Index ◽  
Quinone Profile ◽  
Bacterial Mats ◽  
Different Temperatures

ABSTRACT The respiratory and photosynthetic quinones of microbial mats which occurred in Japanese sulfide-containing neutral-pH hot springs at different temperatures were analyzed by spectrochromatography and mass spectrometry. All of the microbial mats that developed at high temperatures (temperatures above 68°C) were so-called sulfur-turf bacterial mats and produced methionaquinones (MTKs) as the major quinones. A 78°C hot spring sediment had a similar quinone profile.Chloroflexus-mixed mats occurred at temperatures of 61 to 65°C and contained menaquinone 10 (MK-10) as the major component together with significant amounts of either MTKs or plastoquinone 9 (PQ-9). The sunlight-exposed biomats growing at temperatures of 45 to 56°C were all cyanobacterial mats, in which the photosynthetic quinones (PQ-9 and phylloquinone) predominated and MK-10 was the next most abundant component in most cases. Ubiquinones (UQs) were not found or were detected in only small amounts in the biomats growing at temperatures of 50°C and above, whereas the majority of the quinones of a purple photosynthetic mat growing at 34°C were UQs. A numerical analysis of the quinone profiles was performed by using the following three parameters: dissimilarity index (D), microbial divergence index (MDq ), and bioenergetic divergence index (BDq ). A D matrix tree analysis showed that the hot spring mats consisting of the sulfur-turf bacteria, Chloroflexus spp., cyanobacteria, and purple phototrophic bacteria formed distinct clusters. Analyses ofMDq and BDq values indicated that the microbial diversity of hot spring mats decreased as the temperature of the environment increased. The changes in quinone profiles and physiological types of microbial mats in hot springs with thermal gradients are discussed from evolutionary viewpoints.

scholarly journals Horizontal gene transfer of a unique nif island drives convergent evolution of free-living N2-fixing Bradyrhizobium

2021 ◽  
Author(s):  
Jinjin Tao ◽  
Sishuo Wang ◽  
Tianhua Liao ◽  
Haiwei Luo
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Agricultural Research ◽  
Current Knowledge ◽  
Gene Clusters ◽  
Soil Samples ◽  
Genomic Context ◽  
Free Living ◽  
Phylogenomic Analyses ◽  
Conserved Gene

SummaryThe alphaproteobacterial genus Bradyrhizobium has been best known as N2-fixing members that nodulate legumes, supported by the nif and nod gene clusters. Recent environmental surveys show that Bradyrhizobium represents one of the most abundant free-living bacterial lineages in the world’s soils. However, our understanding of Bradyrhizobium comes largely from symbiotic members, biasing the current knowledge of their ecology and evolution. Here, we report the genomes of 88 Bradyrhizobium strains derived from diverse soil samples, including both nif-carrying and non-nif-carrying free-living (nod free) members. Phylogenomic analyses of these and 252 publicly available Bradyrhizobium genomes indicate that nif-carrying free-living members independently evolved from symbiotic ancestors (carrying both nif and nod) multiple times. Intriguingly, the nif phylogeny shows that all nif-carrying free-living members comprise a cluster which branches off earlier than most symbiotic lineages. These results indicate that horizontal gene transfer (HGT) promotes nif expansion among the free-living Bradyrhizobium and that the free-living nif cluster represents a more ancestral version compared to that in symbiotic lineages. Further evidence for this rampant HGT is that the nif in free-living members consistently co-locate with several important genes involved in coping with oxygen tension which are missing from symbiotic members, and that while in free-living Bradyrhizobium nif and the co-locating genes show a highly conserved gene order, they each have distinct genomic context. Given the dominance of Bradyrhizobium in world’s soils, our findings have implications for global nitrogen cycles and agricultural research.

scholarly journals Skinks occur on Terre-de-Bas, Les Saintes (Guadeloupe, French West Indies)

2016 ◽  
Author(s):  
Nicolas Barré ◽  
Antoine Trillot ◽  
Olivier Lorvelec
Keyword(s):  
West Indies ◽  
French West Indies ◽  
Les Saintes

The effect of temperature on the development and survival of the infective larvae of Strongyloides ratti Sandground, 1925

Parasitology ◽  
1968 ◽  
Vol 58 (3) ◽  
pp. 641-651 ◽  
Author(s):  
J. Barrett
Keyword(s):  
Culture Media ◽  
Maximum Activity ◽  
Temperature Adaptation ◽  
Effect Of Temperature ◽  
Free Living ◽  
Larval Stages ◽  
Infective Larvae ◽  
Significant Difference ◽  
Show Maximum Activity ◽  
Different Temperatures

The development of the free-living infective larvae of a homogonic strain Strongyloides ratti is described.The larvae develop only between 15 and 34 °C. Transfer experiments show the temperature block to be in the preparation for the second moult.Within the temperature range 15–34 °C, increasing the temperature speeds up the rate of development of all the larval stages equally, the Q10 for development being 2·5.The maximum percentage development occurs at 20 °C. The percentage development is highest in faeces–peat culture (95% development at 20 °C), whilst the percentage development in charcoal and vermiculite cultures is about the same (75% development at 20 °C.).Larvae grown on charcoal cultures are larger than those grown on vermiculite, which are larger than those grown on peat. No significant difference was found in the length:oesophagus and length:width ratios or in the variability of larvae grown at different temperatures or on different culture media.Different worm densities in the cultures of from 2000 to 10000 larvae per g of culture did not affect either the size of the infective larve or the percentage development.The optimum temperature for survival is 15 °C. Worms grown at 20 °C lived longer than worms grown at any other temperature. There was no evidence of temperature adaptation by the larvae.The infective larvae are positively thermotactic, and show maximum activity at 37 °C.I should like to thank my supervisor, Dr Tate, for his advice and encouragement. The work was carried out during the tenure of a Medical Research Council Scholarship.

Observations on the free-living stages of strongylid nematodes of the horse

Parasitology ◽  
1972 ◽  
Vol 64 (3) ◽  
pp. 461-477 ◽  
Author(s):  
C. P. Ogbourne
Keyword(s):  
Laboratory Experiments ◽  
Field Observations ◽  
Infective Stage ◽  
Free Living ◽  
Rate Of Development ◽  
Infective Larvae ◽  
Strongylus Vulgaris ◽  
Different Temperatures ◽  
Eggs And Larvae

Observations have been made on the development and survival of the free-living stages in faeces deposited out of doors at different times of year, and on the migration of infective larvae to the surrounding herbage. Laboratory experiments were performed to assist in the interpretation of the field observations. Studies were made on the rate of development to the infective stage in faeces kept at different temperatures. The rates at which eggs and larvae of Strongylus vulgaris, S edentatus, S. equinus and Trichonema nassatum developed on faecal-agar cultures at different temperatures were compared. Studies were also made on the effect of desiccation of faeces on the development and survival of the free-living stages. The results of these observations are discussed in relation to the development of herbage infestations on British pastures.

Moisture and temperature requirements in faeces for the development of free-living stages of gastrointestinal nematodes of sheep, cattle and deer

1995 ◽  
Vol 69 (4) ◽  
pp. 357-362 ◽  
Author(s):  
C.E. Rossanigo ◽  
L. Gruner
Keyword(s):  
Haemonchus Contortus ◽  
Gastrointestinal Nematode ◽  
Nematode Species ◽  
Gastrointestinal Nematodes ◽  
Free Living ◽  
Moisture Contents ◽  
Cooperia Oncophora ◽  
Teladorsagia Circumcincta ◽  
Temperature Requirements ◽  
Different Temperatures

AbstractIsolates from eight gastrointestinal nematode species parasitic in sheep, cattle and deer were maintained in sheep, to provide eggs in similar faecal environments and to compare temperature and moisture requirements for their development. Faecal cultures were processed at different temperatures (for four species) and moisture contents (for eight species). At 60% of faecal moisture content (FMC), maximal rates of development (expressed as L3/100 hatchable eggs estimated by an extraction technique from the faeves) were observed at 20, 23 and 28°C respectively for Ostertagia leptospicularis, O. ostertagi, Teladorsagia circumcinctaand Trichostrongylus colunriformis. For the eight species, the curves of development rates as functions of FMC were Gaussian, without modification between 18 and 28°C. Optimal developments were when the FMC ranged from 57 to 68%; low development of 1L3/100eggs were observed when the FMC ranged from 85 to 95% and from 25 to 55%. The main differences between species were in the ability of the eggs of Teladorsagia circumcincta, Trichostrongylus colubriformis, T. vitrinusand Chabertia ovina to develop at lower FMC than Haemonchus contortus, O. ostertagi, O. legptospicularis and Cooperia oncophora.

scholarly journals Characterizing parasitic nematode faunas in faeces and soil using DNA metabarcoding

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Marie Louise Davey ◽  
Kjersti Selstad Utaaker ◽  
Frode Fossøy
Keyword(s):  
Parasitic Nematode ◽  
Cost Effective ◽  
Gastrointestinal Nematodes ◽  
Soil Samples ◽  
Taxonomic Resolution ◽  
Parasitic Nematodes ◽  
Morphological Identification ◽  
Detection Rates ◽  
Non Invasive ◽  
Dna Metabarcoding

Abstract Background Gastrointestinal parasitic nematodes can impact fecundity, development, behaviour, and survival in wild vertebrate populations. Conventional monitoring of gastrointestinal parasitic nematodes in wild populations involves morphological identification of eggs, larvae, and adults from faeces or intestinal samples. Adult worms are typically required for species-level identification, meaning intestinal material from dead animals is needed to characterize the nematode community with high taxonomic resolution. DNA metabarcoding of environmental samples is increasingly used for time- and cost-effective, high-throughput biodiversity monitoring of small-bodied organisms, including parasite communities. Here, we evaluate the potential of DNA metabarcoding of faeces and soil samples for non-invasive monitoring of gastrointestinal parasitic nematode communities in a wild ruminant population. Methods Faeces and intestines were collected from a population of wild reindeer, and soil was collected both from areas showing signs of animal congregation, as well as areas with no signs of animal activity. Gastrointestinal parasitic nematode faunas were characterized using traditional morphological methods that involve flotation and sedimentation steps to concentrate nematode biomass, as well as using DNA metabarcoding. DNA metabarcoding was conducted on bulk samples, in addition to samples having undergone sedimentation and flotation treatments. Results DNA metabarcoding and morphological approaches were largely congruent, recovering similar nematode faunas from all samples. However, metabarcoding provided higher-resolution taxonomic data than morphological identification in both faeces and soil samples. Although concentration of nematode biomass by sedimentation or flotation prior to DNA metabarcoding reduced non-target amplification and increased the diversity of sequence variants recovered from each sample, the pretreatments did not improve species detection rates in soil and faeces samples. Conclusions DNA metabarcoding of bulk faeces samples is a non-invasive, time- and cost-effective method for assessing parasitic nematode populations that provides data with comparable taxonomic resolution to morphological methods that depend on parasitological investigations of dead animals. The successful detection of parasitic gastrointestinal nematodes from soils demonstrates the utility of this approach for mapping distribution and occurrences of the free-living stages of gastrointestinal parasitic nematodes. Graphical abstract

scholarly journals Fungi associated with free-living soil nematodes in Turkey

2015 ◽  
Vol 67 (4) ◽  
pp. 1173-1183
Author(s):  
Salih Karabörklü ◽  
Abdurrahman Ayvaz ◽  
Semih Yilmaz ◽  
Ugur Azizoglu
Keyword(s):  
Phylogenetic Trees ◽  
World Wide ◽  
Large Subunit ◽  
Soil Samples ◽  
Soil Types ◽  
Soil Nematodes ◽  
Free Living ◽  
Fungal Strains

Free-living soil nematodes have successfully adapted world-wide to nearly all soil types from the highest to the lowest of elevations. In the current study, nematodes were isolated from soil samples and fungi associated with these free-living soil nematodes were determined. Large subunit (LSU) rDNAs of nematode-associated fungi were amplified and sequenced to construct phylogenetic trees. Nematode-associated fungi were observed in six nematode strains belonging to Acrobeloides, Steinernema and Cephalobus genera in different habitats. Malassezia and Cladosporium fungal strains indicated an association with Acrobeloides and Cephalobus nematodes, while Alternaria strains demonstrated an association with the Steinernema strain. Interactions between fungi and free-living nematodes in soil are discussed. We suggest that nematodes act as vectors for fungi.

Sign in / Sign up

Export Citation Format

Share Document