Chemotactic and temperature-dependent responses of the Strongyloidoidea superfamily of nematodes

Parasitology ◽  
2021 ◽  
pp. 1-8
Author(s):  
Alex Dulovic ◽  
Mat Norman ◽  
Dorothee Harbecke ◽  
Adrian Streit
Keyword(s):  
Complex Mixture ◽  
Temperature Response ◽  
Parasitic Nematodes ◽  
Temperature Dependent ◽  
Direct Stimulation ◽  
Multiple Cues ◽  
Infective Larvae ◽  
Olfactory Sensation ◽  
Host Seeking ◽  
Infection Mode

Abstract Host-seeking behaviour and how a parasite identifies the correct host to infect remains a poorly understood area of parasitology. What is currently known is that host sensation and seeking behaviour is formed from a complex mixture of chemo-, thermo- and mechanosensory behaviours, of which chemosensation is the best studied. Previous studies of olfaction in parasitic nematodes suggested that this behaviour appears to be more closely related to target host and infection mode than phylogeny. However, there has not yet been a study comparing the chemotactic and temperature-dependent behaviours of very closely related parasitic and non-parasitic nematodes. To this end, we examined the temperature-dependent and chemotactic responses of the Strongyloidoidea superfamily of nematodes. We found differences in temperature response between the different species and within infective larvae. Chemotactic responses were highly divergent, with different attraction profiles between all species studied. When examining direct stimulation with fur, we found that it was insufficient to cause an attractive response. Overall, our results support the notion that olfactory sensation is more closely related to lifestyle and host range than phylogeny, and that multiple cues are required to initiate host-seeking behaviour.

scholarly journals Temperature-dependent changes in the host-seeking behaviors of parasitic nematodes

BMC Biology ◽  
2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Joon Ha Lee ◽  
Adler R. Dillman ◽  
Elissa A. Hallem
Keyword(s):  
Parasitic Nematodes ◽  
Temperature Dependent ◽  
Host Seeking

scholarly journals Chemosensory mechanisms of host seeking and infectivity in skin-penetrating nematodes

2020 ◽  
Vol 117 (30) ◽  
pp. 17913-17923 ◽  
Author(s):  
Spencer S. Gang ◽  
Michelle L. Castelletto ◽  
Emily Yang ◽  
Felicitas Ruiz ◽  
Taylor M. Brown ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Strongyloides Stercoralis ◽  
Sensory Cues ◽  
Ancylostoma Ceylanicum ◽  
Free Living ◽  
Infective Larvae ◽  
Host Seeking ◽  
Third Stage ◽  
Olfactory Preferences ◽  
Insight Into

Approximately 800 million people worldwide are infected with one or more species of skin-penetrating nematodes. These parasites persist in the environment as developmentally arrested third-stage infective larvae (iL3s) that navigate toward host-emitted cues, contact host skin, and penetrate the skin. iL3s then reinitiate development inside the host in response to sensory cues, a process called activation. Here, we investigate how chemosensation drives host seeking and activation in skin-penetrating nematodes. We show that the olfactory preferences of iL3s are categorically different from those of free-living adults, which may restrict host seeking to iL3s. The human-parasitic threadwormStrongyloides stercoralisand hookwormAncylostoma ceylanicumhave highly dissimilar olfactory preferences, suggesting that these two species may use distinct strategies to target humans. CRISPR/Cas9-mediated mutagenesis of theS. stercoralis tax-4gene abolishes iL3 attraction to a host-emitted odorant and prevents activation. Our results suggest an important role for chemosensation in iL3 host seeking and infectivity and provide insight into the molecular mechanisms that underlie these processes.

scholarly journals A Sensory Code for Host Seeking in Parasitic Nematodes

2011 ◽  
Vol 21 (5) ◽  
pp. 377-383 ◽  
Author(s):  
Elissa A. Hallem ◽  
Adler R. Dillman ◽  
Annie V. Hong ◽  
Yuanjun Zhang ◽  
Jessica M. Yano ◽  
...  
Keyword(s):  
Parasitic Nematodes ◽  
Host Seeking ◽  
Sensory Code

Vertical migration by the infective larvae of three species of parasitic nematodes: is the behaviour really a response to gravity?

Parasitology ◽  
2002 ◽  
Vol 125 (06) ◽  
pp. 553-560 ◽  
Author(s):  
J. SCIACCA ◽  
A. KETSCHEK ◽  
W. M. FORBES ◽  
R. BOSTON ◽  
J. GUERRERO ◽  
...  
Keyword(s):  
Vertical Migration ◽  
Parasitic Nematodes ◽  
Infective Larvae

scholarly journals Rhabditophanes diutinus a parthenogenetic clade IV nematode with dauer larvae

2020 ◽  
Vol 16 (12) ◽  
pp. e1009113
Author(s):  
Alex Dulovic ◽  
Tess Renahan ◽  
Waltraud Röseler ◽  
Christian Rödelsperger ◽  
Ann M. Rose ◽  
...  
Keyword(s):  
Life Cycle ◽  
Expression Patterns ◽  
Parasitic Nematodes ◽  
Comparative Genomic ◽  
Phylogenetic Distance ◽  
Life Stages ◽  
Model Species ◽  
Free Living ◽  
Infective Larvae ◽  
Dauer Larvae

Comparative studies using non-parasitic model species such as Caenorhabditis elegans, have been very helpful in investigating the basic biology and evolution of parasitic nematodes. However, as phylogenetic distance increases, these comparisons become more difficult, particularly when outside of the nematode clade to which C. elegans belongs (V). One of the reasons C. elegans has nevertheless been used for these comparisons, is that closely related well characterized free-living species that can serve as models for parasites of interest are frequently not available. The Clade IV parasitic nematodes Strongyloides are of great research interest due to their life cycle and other unique biological features, as well as their medical and veterinary importance. Rhabditophanes, a closely related free-living genus, forms part of the Strongyloidoidea nematode superfamily. Rhabditophanes diutinus (= R. sp. KR3021) was included in the recent comparative genomic analysis of the Strongyloididae, providing some insight into the genomic nature of parasitism. However, very little is known about this species, limiting its usefulness as a research model. Here we provide a species description, name the species as R. diutinus and investigate its life cycle and subsequently gene expression in multiple life stages. We identified two previously unreported starvation induced life stages: dauer larvae and arrested J2 (J2A) larvae. The dauer larvae are morphologically similar to and are the same developmental stage as dauers in C. elegans and infective larvae in Strongyloides. As in C. elegans and Strongyloides, dauer formation is inhibited by treatment with dafachronic acid, indicating some genetic control mechanisms are conserved. Similarly, the expression patterns of putative dauer/infective larva control genes resemble each other, in particular between R. diutinus and Strongyloides spp. These findings illustrate and increase the usefulness of R. diutinus as a non-parasitic, easy to work with model species for the Strongyloididae for studying the evolution of parasitism as well as many aspects of the biology of Strongyloides spp, in particular the formation of infective larvae.

Faecal dry matter and nematode infection in parasite-resistant Merino sheep in Australia

2009 ◽  
Vol 2009 ◽  
pp. 29-29
Author(s):  
A R Williams ◽  
L J E Karlsson ◽  
D G Palmer ◽  
P E Vercoe ◽  
I H Williams ◽  
...  
Keyword(s):  
Dry Matter ◽  
Parasitic Nematode ◽  
Parasitic Nematodes ◽  
Parasite Control ◽  
Merino Sheep ◽  
Infective Larvae ◽  
The United Kingdom ◽  
Teladorsagia Circumcincta ◽  
Nematode Larvae ◽  
Southern Half

Scouring (diarrhoea) is a major concern for sheep producers as the accumulation of faecal material (dags) around the breech pre-disposes sheep to flystrike. Scouring occurs when the consistency of faeces is fluid with a low percentage of dry matter. In temperate areas such as the southern half of Australia, New Zealand and the United Kingdom, scouring is associated with ingestion of parasitic nematode larvae, mainly Teladorsagia circumcincta and Trichostrongylus colubriformis (Larsen et al., 1994). Breeding sheep to be resistant to these nematodes is a sustainable parasite-control strategy due to reduced reliance on chemical treatment. However, in adult sheep, scouring appears equally prevalent in resistant animals and, in some environments, is even more severe than in susceptible sheep (Karlsson et al., 2004). In this experiment, we investigated how faecal dry matter (FDM) in sheep from a flock bred for resistance to parasitic nematodes changed when challenged with infective larvae. We expected that FDM would be lower in challenged sheep compared to unchallenged controls, and FDM would also be lower in sheep with high dag scores compared to sheep with low dag scores.

scholarly journals Quality or decomposer efficiency – which is most important in the temperature response of litter decomposition? A modelling study using the GLUE methodology

2011 ◽  
Vol 8 (2) ◽  
pp. 477-487 ◽  
Author(s):  
J. Å. M. Wetterstedt ◽  
G. I. Ågren
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Litter Quality ◽  
Incubation Temperature ◽  
Temperature Response ◽  
Temperature History ◽  
Temperature Dependent ◽  
Substrate Quality ◽  
Needle Litter ◽  
Q Model

Abstract. We still lack full mechanistic understanding of how the temperature history affects the future decomposition rate of litter and soil organic matter. To explore that, we used the GLUE modelling framework together with the Q-model and data from a needle litter incubation experiment to compare a differential temperature response of litter qualities to a temperature-dependent decomposer efficiency. The needle litter incubation was a full factorial design with the initial and final temperatures 5, 15 and 25 °C. Samples were moved from the initial to the final temperature when approximately 12% of the initial carbon had been respired and the experiment terminated when an additional 12% had been lost. We used four variations of the Q-model; the litter was described as having one or two initial quality values and the decomposer efficiency was either fixed or allowed to vary with temperature. All variations were calibrated with good fits to the data subsets with equal initial and final temperatures. Evaluation against temperature shift subsets also showed good results, except just after the change in temperature where all variations predicted a smaller response than observed. The effects of having one or two initial litter quality values (fixed decomposer efficiency) on end-of-experiment litter quality and respiration were marginal. Letting decomposer efficiency vary with temperature resulted in a decrease in efficiency between 5 and 15 °C but no change between 15 and 25 °C and in substantial differences in litter quality at the end of the initial incubation in response to incubation temperature. The temperature response of decomposition through temperature dependent decomposer efficiency proved, therefore, to be more important than the differential response to different substrate qualities. These results suggests that it may be important to consider other factors (e.g. microbial efficiency, changing substrate composition) than the temperature sensitivity coupled to substrate quality when evaluating effects of temperature changes on soil organic matter stability.

The respiratory metabolism of parasitic nematodes

Parasitology ◽  
1948 ◽  
Vol 39 (1-2) ◽  
pp. 105-109 ◽  
Author(s):  
W. P. Rogers
Keyword(s):  
Haemonchus Contortus ◽  
Potassium Cyanide ◽  
The Other ◽  
Parasitic Nematodes ◽  
Ascaridia Galli ◽  
Reserve Material ◽  
Infective Larvae ◽  
Third Stage ◽  
Area Basis ◽  
Surface Area Basis

1. Qo2 values for Haemonchus contortus egs varied between − 9·7 and − 12·6 according to the degree of development of the embryos. The r.q. was in the region of 0·6.2. Young infective larvae of Nippostrongylus muris had a high Qo2 (−18·4), which fell as the larvae aged. Third stage Haemonchus contortus larvae gave similar results. The respiration was not affected by exsheathment.3. Adult parasites gave Qo2 values as follows: Ascaridia galli, − 2·5; Nematodirus spp., − 5·1; Nippostrongylus muris, − 6·8; Neoaplectana glaseri, − 12·6. When calculated on a surface area basis, Ascaridia galli had an oxygen uptake which was much higher than that of the other organisms.4. Qco2 values were small. The r.q. of infective larvae, which contain fat as reserve material, was about 0·72. The other forms which contained much glycogen as well as fat had r.q. values between 0·6 and 0·7. A. galli was an exception in that an r.q. of about 0·95 was obtained.5. Potassium cyanide inhibited respiration in all the forms examined.The author is indebted to Dr R. W. Glaser for supplying a strain of Neoaplectana glaseri.

scholarly journals Transcriptional network of the industrial hybrid Saccharomyces pastorianus reveals temperature-dependent allele expression bias and preferential orthologous protein assemblies

2021 ◽  
Author(s):  
Soukaina Timouma ◽  
Laura Natalia Balarezo-Cisneros ◽  
Javier Pinto Aguirre ◽  
Roberto De la Cerda ◽  
Ursula M Bond ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Temperature Response ◽  
Protein Isoforms ◽  
Temperature Dependent ◽  
Transcriptional Signature ◽  
Parental Allele ◽  
Saccharomyces Pastorianus ◽  
Transcriptional Pattern ◽  
Cold Tolerant ◽  
Hybrid Genes

Saccharomyces pastorianus is an industrial natural yeast evolved from different hybridisation events between the mesophilic S. cerevisiae and the cold-tolerant S. eubayanus. This complex aneuploid hybrid carries multiple copies of the parental alleles alongside specific hybrid genes and encodes for multiple protein isoforms which impart novel phenotypes, such as the strong ability to ferment at low temperature. These characteristics lead to agonistic or antagonistic competition for substrates and a plethora of biochemical activities, resulting in a unique cellular metabolism. Here, we investigated the transcriptional signature of the different orthologous alleles in S. pastorianus during temperature shifts. We identified temperature-dependent media-independent genes and showed that 35% have their regulation dependent on extracellular leucine uptake, suggesting an interplay between leucine metabolism and temperature response. The analysis of the expression of ortholog parental alleles unveiled that the majority of the genes express preferentially one parental allele over the other, and that S. eubayanus-like alleles are significantly over-represented among the genes involved in cold acclimatisation. The presence of functionally redundant parental alleles may impact on the nature of protein complexes established in the hybrid, where both parental alleles are competing. Our expression data indicate that the majority of the protein complexes established in the hybrid are likely to be either exclusively chimeric or uni-specific, and that the redundancy is discouraged, a scenario which fits well with the stoichiometric balance-hypothesis. This study offers a first overview of the transcriptional pattern of S. pastorianus and provide a rationalisation for its unique industrial traits at expression level.

scholarly journals Mechanisms of host seeking by parasitic nematodes

2016 ◽  
Vol 208 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Spencer S. Gang ◽  
Elissa A. Hallem
Keyword(s):  
Parasitic Nematodes ◽  
Host Seeking
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