Effects of antifouling booster biocide Irgarol 1051 on the structure of free living nematodes: a laboratory experiment

2016 ◽  
Vol 18 (7) ◽  
pp. 832-843 ◽  
Author(s):  
Amel Hannachi ◽  
Soumaya Elarbaoui ◽  
Abdelhafidh Khazri ◽  
Fabio D'Agostino ◽  
Badreddine Sellami ◽  
...  
Keyword(s):  
Laboratory Experiment ◽  
Trophic Structure ◽  
Mesocosm Experiment ◽  
Free Living ◽  
Irgarol 1051 ◽  
Nematode Diversity

A mesocosm experiment was conducted to evaluate the effects of Irgarol on nematode diversity, composition and trophic structure.

Molecular characterization of free-living nematodes from Kermadec Trench (Nematoda: Aegialoalaimidae, Xyalidae) with description of Aegialoalaimus tereticauda n. sp.

Zootaxa ◽  
2021 ◽  
Vol 4949 (2) ◽  
pp. 341-352
Author(s):  
DANIEL LEDUC ◽  
ZENG QI ZHAO
Keyword(s):  
Buccal Cavity ◽  
Nerve Ring ◽  
Free Living ◽  
Invertebrate Species ◽  
Current Classification ◽  
Nematode Diversity ◽  
Taxonomic Research ◽  
A Site ◽  
A New Species

The Kermadec Trench is the world’s fifth deepest trench and extends from approximately 26 to 36°S near the northeastern tip of New Zealand’s North Island. Here, we describe a new species of Aegialoalaimus, a nematode genus with unusual buccal cavity and pharynx morphology, from a site at 9540 metres water depth in Kermadec Trench, and provide the first SSU and D2–D3 of LSU sequences for Aegialoalaimus, Manganonema, Metasphaerolaimus constrictus and Daptonema amphorum. Aegialoalaimus tereticauda n. sp. is characterised by body length 755–864 µm, cephalic sensilla papilliform (< 1 µm long), excretory pore located slightly anterior to posterior bulb in males and slightly anterior to nerve ring in females, arcuate spicules 18–22 µm long, gubernaculum present, precloacal supplements absent, and cylindrical tail 58–64 µm long with rounded tip. Relationships between Aegialoalaimus and Chromadorean orders could not be elucidated based on our SSU analysis; no link could be found with the Plectida, where the Aegialoalaimidae is currently placed, or with the Isolamiida or Cylindrolaimus (Areaolaimida), which share a similar and unusual buccal and pharynx morphology. Our SSU phylogenetic analysis confirms the placement of Manganonema within the Xyalidae, although relationships with other xyalid genera remain unclear. The Sphaerolaimidae formed a clade together with the Monhysteridae, which contradicts the current classification where the Sphaerolaimidae and Xyalidae are classified together into the superfamily Sphaerolaimoidea and the Monhysteridae into the Monhysteroidea. Although limited research has been conducted on the nematode diversity in Kermadec Trench to date, the available data show that half of all invertebrate species known from the trench are nematodes, which highlights the importance of conducting further taxonomic research on this group in hadal environments. 

scholarly journals Earthworms and Plant Residues Modify Nematodes in Tropical Cropping Soils (Madagascar): A Mesocosm Experiment

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Cécile Villenave ◽  
Bodo Rabary ◽  
Emilie Kichenin ◽  
Djibril Djigal ◽  
Eric Blanchart
Keyword(s):  
Community Structure ◽  
Soil Surface ◽  
Nematode Community ◽  
Mesocosm Experiment ◽  
Plant Residues ◽  
Biological Processes ◽  
Organic Residues ◽  
Free Living ◽  
Specific Stimulation ◽  
Stimulation Of

Free-living nematodes present several characteristics that have led to their use as bioindicators of soil quality. Analyzing the structure of nematofauna is a pertinent way to understand soil biological processes. Earthworms play an important role in soil biological functioning and organic matter dynamics. Their effects on soil nematofauna have seldom been studied. We studied the effect of the tropical endogeic earthworm,Pontoscolex corethrurus, on nematode community structure in a 5-month field mesocosm experiment conducted in Madagascar. Ten different treatments with or without earthworms and with or without organic residues (rice, soybean) were compared. Organic residues were applied on the soil surface or mixed with the soil. The abundance of nematodes (bacterial and fungal feeders) was higher in presence ofP. corethrurusthan in their absence. The type of plant residues as well as their localisation had significant effects on the abundance and composition of soil nematodes. The analysis of nematode community structure showed that earthworm activity led to an overall activation of the microbial compartment without specific stimulation of the bacterial or fungal compartment.

scholarly journals Drought intensification alters the composition, body size, and trophic structure of invertebrate assemblages in a stream mesocosm experiment

2019 ◽  
Author(s):  
Thomas W. H. Aspin ◽  
Kris Hart ◽  
Kieran Khamis ◽  
Alexander M. Milner ◽  
Matthew J. O'Callaghan ◽  
...  
Keyword(s):  
Body Size ◽  
Trophic Structure ◽  
Mesocosm Experiment ◽  
Stream Mesocosm ◽  
Invertebrate Assemblages

Responses of soil nematode communities to agroecological crop management systems

Nematology ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 209-221 ◽  
Author(s):  
Débora Cristina Santiago ◽  
Giovani de Oliveira Arieira ◽  
Edinei de Almeida ◽  
Maria de Fátima Guimarães
Keyword(s):  
Trophic Structure ◽  
Biological Indicators ◽  
Management Systems ◽  
Soil Nematode ◽  
Canavalia Ensiformis ◽  
Nematode Communities ◽  
Plant Feeding ◽  
Nematode Diversity ◽  
Crop Management Systems ◽  
The Impact

Soil nematodes are sensitive to human intervention and widely used as biological indicators of disruptions and alterations in soil quality. The aim of this work was to identify nematodes that are good biological indicators in maize crops under different management systems, and to establish the impact levels of these systems. Soil samples were collected over a 3-year period at a depth of 0.0-0.3 m in areas under six different management systems for maize (Zea mays) monoculture, and intercropped maize and Canavalia ensiformis. Six areas of native vegetation were also assessed to provide a reference for ecological balance. After identification and counting, nematode communities were characterised according to abundance (total and relative), diversity (identified genera and diversity indexes), trophic structure and ecological maturity (disturbance indexes). Nematodes proved to be good ecological indicators, responding to the systems employed. Intercropping maize and Canavalia ensiformis in at least one assessment year reduced disruption and increased nematode diversity, which were both verified based on specific indexes. It was also observed that the maize monoculture increased disruption leading to a drop in nematode fauna diversity and an increase in the incidence of plant-feeding nematodes.

Shift in C and N humification during legume litter decomposition in an acid tropical Ferralsol

Soil Research ◽  
2012 ◽  
Vol 50 (5) ◽  
pp. 380 ◽  
Author(s):  
Jorge Sierra ◽  
Natacha Motisi
Keyword(s):  
Laboratory Experiment ◽  
Litter Decomposition ◽  
Tropical Soils ◽  
Term Effect ◽  
Mesocosm Experiment ◽  
Short Term ◽  
Soil C ◽  
Long Term Effect ◽  
C And N

Several long-term studies on tropical soils have shown that legume residue incorporation increases soil nitrogen (N) sequestration more than that of carbon (C), resulting in a fall in the C/N ratio. This study was designed to assess the short-term effect of legume litter addition on N supply and the long-term effect on soil organic matter (SOM) formation and soil C/N decrease. The long-term effect was evaluated in a 2-year mesocosm experiment with high and frequent organic inputs from two types of legume litter with different C/N ratios, using stable isotope techniques. The short-term effect of litter was analysed using four different litters in 3-month laboratory incubations. A model of litter decomposition was used to describe C and N kinetics in the laboratory experiment and to verify whether the long-term effect of litter may be predicted from short-term incubations. The results of the mesocosm experiment confirmed that legume inputs increased soil organic N (mean +21%) more than organic C (mean +15%) (P = 0.05). Although no differences between litters were observed for C dynamics, N sequestration (14% and 28%) and the final soil C/N (12.0 and 10.8) varied with litter C/N (34.4 and 16.1, respectively). The laboratory experiment and model outputs confirmed these findings and indicated that the higher N sequestration was due to a change in the parameters describing humification of C and N coming from litter. This change depended on litter quality and was greater for litters with low C/N—C humification 0.66 g C g–1 C and N humification 0.76 g N g–1 N for litter C/N 16.1. Carbon and N sequestration were greater in the laboratory experiment, due to a higher mineralisation of the new SOM derived from litter in the mesocosm experiment—32% and 15% for the mesocosm and the laboratory experiments, respectively. Our results indicated that the decrease in soil C/N and the rapid mineralisation of new SOM should be considered in models of litter decomposition to respond correctly to the long- and the short-term effects of legume litter inputs in tropical soils.

scholarly journals Effect of heavy metals on soil nematode communities in the vicinity of a metallurgical plant in North Slovakia

2015 ◽  
Vol 52 (3) ◽  
pp. 252-260 ◽  
Author(s):  
P. Šalamún ◽  
V. Hanzelová ◽  
D. Miklisová ◽  
T. Brázová
Keyword(s):  
Stress Responses ◽  
Industrial Pollution ◽  
Pollution Source ◽  
Soil Nematode ◽  
Free Living ◽  
Nematode Communities ◽  
Generic Composition ◽  
Free Living Nematode ◽  
Nematode Diversity ◽  
Remote Sites

Abstract The effect of industrial pollution from chromium ferroalloys production on soil free-living nematode assemblages, c-p groups and generic composition was investigated along 7-km transect. From trace elements (Cr, Cu, Ni and Pb), only chromium exceeded the thresholds for uncontaminated soils (10 mg.kg-1) near the pollution source. In contrast mobilizable fraction of Cr has increased with the distance from the pollution source and was found to be positively correlated with Cox, soil pH, and moisture. Generic richness (nematode diversity) was also higher at remote sites. The low contamination has no significant impact on the nematode communities as illustrated by the c-p groups composition and balanced community structure. Widely applied ecological indices SI and EI also proved maturing ecosystem without any significant stress responses

Free-living marine nematode diversity from the Indian coasts

2016 ◽  
Vol 48 (1) ◽  
pp. 179-194
Author(s):  
Moumita Ghosh ◽  
Sumit Mandal
Keyword(s):  
Marine Nematode ◽  
Free Living ◽  
Nematode Diversity

scholarly journals Free-living marine nematodes diversity at Ponta Delgada-São Miguel (Azores archipelago, North-East Atlantic Ocean): first results from shallow soft-bottom habitats

2020 ◽  
Author(s):  
Alberto de Jesús Navarrete ◽  
Víctor Aramayo ◽  
Anitha Mary Davidson ◽  
Ana Cristina Costa
Keyword(s):  
Atlantic Ocean ◽  
Sandy Beaches ◽  
Future Research ◽  
Marine Nematode ◽  
East Atlantic ◽  
Free Living ◽  
Azores Archipelago ◽  
North East ◽  
First Results ◽  
Nematode Diversity

AbstractContrasting (sand, algae, rocky-dominated, mixed) benthic habitats were sampled to characterize marine nematode diversity inhabiting surface sediments in São Miguel (Azores, North-East Atlantic Ocean) in July 2019. Nematodes were extracted from the surface layer of sediments and morphologically identified using light microscopy. Nematode taxonomy was based on living/fresh specimens) to ensure a suitable recognition of morphological traits. Our results provide a preliminary checklist of free-living marine nematode genera from 21 intertidal and sublittoral sandy beach sites along the coast of São Miguel island, Azores archipelago, Portugal. The nematode fauna was represented by 4 orders, 21 families, and 43 genera. Cyatholaimus, Desmodora and Daptonema had two morphospecies each. Enoplida was represented by 8 families and 13 genera, while Chromadorida by 7 families and 18 genera, the latter corresponding to the most diverse nematode group. Monhysterida had 5 families and 10 genera and Araeolaimida was represented by a single 1 family and 2 genera. The most common genera (i.e., accounting for 75% of all organisms) included Adoncholaimus (most abundant genus, 32 specimens), Axonolaimus (18), Cyatholaimus (17), Enoploides (13), Rhabdocoma, and Acanthopharynx (11). Viscosia and Enoplolaimus were represented by 7 specimens, whilst Halalaimus, Desmoscolex, Monophostia, Daptonema, and Theristus obtained only 6 each. The dominant nematode taxa of São Miguel island have been commonly previously reported in other coastal habitats including sandy beaches. They can be considered typical meiofaunal components of intertidal sandy beaches. Many of the nematode morphotypes found in São Miguel island could represent new species to science. As far as we know, this is the first report on free-living nematodes for São Miguel Island and for marine shallow water in the Azores. Our findings will serve as an import baseline for future research aiming to improve our understating of nematode communities in volcanic islands such as São Miguel in the Azores archipelago.

Ultrastructure of neuromuscular relationships in the canine heartworm (dirofilaria immitis)

1986 ◽  
Vol 44 ◽  
pp. 278-279
Author(s):  
W. L. Steffens ◽  
Nancy B. Roberts ◽  
J. M. Bowen
Keyword(s):  
Dirofilaria Immitis ◽  
Domestic Dogs ◽  
Structural Description ◽  
Pharmacological Effects ◽  
Free Living ◽  
Canine Heartworm ◽  
The World ◽  
Synaptic Region ◽  
Muscle Innervation ◽  
Insight Into

The canine heartworm is a common and serious nematode parasite of domestic dogs in many parts of the world. Although nematode neuroanatomy is fairly well documented, the emphasis has been on sensory anatomy and primarily in free-living soil species and ascarids. Lee and Miller reported on the muscular anatomy in the heartworm, but provided little insight into the peripheral nervous system or myoneural relationships. The classical fine-structural description of nematode muscle innervation is Rosenbluth's earlier work in Ascaris. Since the pharmacological effects of some nematacides currently being developed are neuromuscular in nature, a better understanding of heartworm myoneural anatomy, particularly in reference to the synaptic region is warranted.

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