scholarly journals Natural variation in Pristionchus pacificus dauer formation reveals cross-preference rather than self-preference of nematode dauer pheromones

2011 ◽  
Vol 278 (1719) ◽  
pp. 2784-2790 ◽  
Author(s):  
Melanie G. Mayer ◽  
Ralf J. Sommer
Keyword(s):  
Natural Variation ◽  
Strong Association ◽  
Cross Reactivity ◽  
Model Organisms ◽  
Laboratory Model ◽  
Experimental Conditions ◽  
Pristionchus Pacificus ◽  
In The Wild ◽  
Dauer Formation ◽  
Dauer Larvae

Many free-living nematodes, including the laboratory model organisms Caenorhabditis elegans and Pristionchus pacificus , have a choice between direct and indirect development, representing an important case of phenotypic plasticity. Under harsh environmental conditions, these nematodes form dauer larvae, which arrest development, show high resistance to environmental stress and constitute a dispersal stage. Pristionchus pacificus occurs in a strong association with scarab beetles in the wild and remains in the dauer stage on the living beetle. Here, we explored the circumstances under which P. pacificus enters and exits the dauer stage by using a natural variation approach. The analysis of survival, recovery and fitness after dauer exit of eight P. pacificus strains revealed that dauer larvae can survive for up to 1 year under experimental conditions. In a second experiment, we isolated dauer pheromones from 16 P. pacificus strains, and tested for natural variation in pheromone production and sensitivity in cross-reactivity assays. Surprisingly, 13 of the 16 strains produce a pheromone that induces the highest dauer formation in individuals of other genotypes. These results argue against a simple adaptation model for natural variation in dauer formation and suggest that strains may have evolved to induce dauer formation precociously in other strains in order to reduce the fitness of these strains. We therefore discuss intraspecific competition among genotypes as a previously unconsidered aspect of dauer formation.

scholarly journals Peromyscus mice as a model for studying natural variation

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Nicole L Bedford ◽  
Hopi E Hoekstra
Keyword(s):  
Disease Ecology ◽  
Natural Variation ◽  
Laboratory Experiments ◽  
Deer Mouse ◽  
Model Organisms ◽  
Field Observations ◽  
Terrestrial Habitat ◽  
In The Wild ◽  
History Of ◽  
And Behavior

The deer mouse (genus Peromyscus) is the most abundant mammal in North America, and it occupies almost every type of terrestrial habitat. It is not surprising therefore that the natural history of Peromyscus is among the best studied of any small mammal. For decades, the deer mouse has contributed to our understanding of population genetics, disease ecology, longevity, endocrinology and behavior. Over a century's worth of detailed descriptive studies of Peromyscus in the wild, coupled with emerging genetic and genomic techniques, have now positioned these mice as model organisms for the study of natural variation and adaptation. Recent work, combining field observations and laboratory experiments, has lead to exciting advances in a number of fields—from evolution and genetics, to physiology and neurobiology.

scholarly journals A Genome Scan for Quantitative Trait Loci in a Wild Population of Red Deer (Cervus elaphus)

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1863-1873 ◽  
Author(s):  
J Slate ◽  
P M Visscher ◽  
S MacGregor ◽  
D Stevens ◽  
M L Tate ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Cervus Elaphus ◽  
Quantitative Trait ◽  
Red Deer ◽  
Wild Population ◽  
Additive Genetic Variance ◽  
Model Organisms ◽  
A Genome ◽  
Trait Loci ◽  
In The Wild

Abstract Recent empirical evidence indicates that although fitness and fitness components tend to have low heritability in natural populations, they may nonetheless have relatively large components of additive genetic variance. The molecular basis of additive genetic variation has been investigated in model organisms but never in the wild. In this article we describe an attempt to map quantitative trait loci (QTL) for birth weight (a trait positively associated with overall fitness) in an unmanipulated, wild population of red deer (Cervus elaphus). Two approaches were used: interval mapping by linear regression within half-sib families and a variance components analysis of a six-generation pedigree of >350 animals. Evidence for segregating QTL was found on three linkage groups, one of which was significant at the genome-wide suggestive linkage threshold. To our knowledge this is the first time that a QTL for any trait has been mapped in a wild mammal population. It is hoped that this study will stimulate further investigations of the genetic architecture of fitness traits in the wild.

scholarly journals Cyclodextrins, Natural Compounds, and Plant Bioactives—A Nutritional Perspective

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 401
Author(s):  
Svenja Wüpper ◽  
Kai Lüersen ◽  
Gerald Rimbach
Keyword(s):  
Intestinal Flora ◽  
Aqueous Solubility ◽  
Outer Wall ◽  
Natural Compounds ◽  
Model Organisms ◽  
Laboratory Model ◽  
Internal Cavity ◽  
Pentacyclic Triterpenoids ◽  
Starch Derivatives ◽  
Improved Stability

Cyclodextrins (CDs) are a group of cyclic oligosaccharides produced from starch or starch derivatives. They contain six (αCD), seven (βCD), eight (γCD), or more glucopyranose monomers linked via α-1,4-glycosidic bonds. CDs have a truncated cone shape with a hydrophilic outer wall and a less hydrophilic inner wall, the latter forming a more apolar internal cavity. Because of this special architecture, CDs are soluble in water and can simultaneously host lipophilic guest molecules. The major advantage of inclusion into CDs is increased aqueous solubility of such lipophilic substances. Accordingly, we present studies where the complexation of natural compounds such as propolis and dietary plant bioactives (e.g., tocotrienol, pentacyclic triterpenoids, curcumin) with γCD resulted in improved stability, bioavailability, and bioactivity in various laboratory model organisms and in humans. We also address safety aspects that may arise from increased bioavailability of plant extracts or natural compounds owing to CD complexation. When orally administered, α- and βCD—which are inert to intestinal digestion—are fermented by the human intestinal flora, while γCD is almost completely degraded to glucose units by α-amylase. Hence, recent reports indicate that empty γCD supplementation exhibits metabolic activity on its own, which may provide opportunities for new applications.

scholarly journals REPRODUCTION IN CAGE POPULATIONS OF A POLYMORPHISM REGULARLY OBSERVED IN THE NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER IN FRANCE

Genetics ◽  
1978 ◽  
Vol 88 (4) ◽  
pp. 755-759
Author(s):  
Annie Fleuriet
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Rate Of Return ◽  
Rapid Rate ◽  
Experimental Conditions ◽  
Co2 Sensitivity ◽  
In The Wild ◽  
Strong Forces

ABSTRACT Polymorphism for both alleles of a gene ref(2)P, which is a usual trait of French natural populations of Drosophila melanogaster, can be reproduced in experimental conditions. ref(2)P is a gene for resistance to the hereditary, noncontagious Rhabdovirus α, responsible for CO2 sensitivity in Drosophila melanogaster. The equilibrium frequencies observed in cages are the same as in the wild, whether α virus is present or not. The rapid rate of return to these equilibrium frequencies indicates that strong forces, which remain to be determined, are responsible for the maintenance of this polymorphism.

Pristionchus pacificus daf-16 is essential for dauer formation but dispensable for mouth form dimorphism

Development ◽  
2011 ◽  
Vol 138 (7) ◽  
pp. 1281-1284 ◽  
Author(s):  
Akira Ogawa ◽  
Gilberto Bento ◽  
Gabi Bartelmes ◽  
Christoph Dieterich ◽  
Ralf J. Sommer
Keyword(s):  
Pristionchus Pacificus ◽  
Dauer Formation

scholarly journals Rapid immunoassays for detection of anabolic nortestosterone in dietary supplements

2013 ◽  
Vol 31 (No. 5) ◽  
pp. 514-519 ◽  
Author(s):  
B. Holubová ◽  
S. Göselová ◽  
L. Ševčíková ◽  
M. Vlach ◽  
M. Blažková ◽  
...  
Keyword(s):  
Dietary Supplements ◽  
Rapid Detection ◽  
Visual Detection ◽  
Limit Of Detection ◽  
Polyclonal Antibodies ◽  
Cross Reactivity ◽  
Rapid Analysis ◽  
Experimental Conditions ◽  
Immunochromatographic Strip ◽  
Strip Test

An enzyme immunoassay (ELISA) and an immunochromatographic strip were designed for a rapid detection of nortestosterone in dietary supplements. Two polyclonal antibodies and two types of nortestosterone-protein coating conjugates were tested to develop the most appropriate method. Under optimal experimental conditions, the most sensitive ELISA achieved the IC<sub>50 </sub>and the limit of detection values of 6.41 and 0.09 ng/ml, respectively. The assay specificity was tested measuring cross-reactivity of several steroids. The interference with the assay was negligible (&lt; 0.1%), except for cross-reactivity with another frequently abused steroid testosterone (23%). The optimised gold particle-based immunochromatographic strip provided in semi-quantitative test a visual detection limit of 1&nbsp;ng/ml. None of these methods showed the interference using a filtrate of the suspension of non-contaminated sample. After the validation for particular matrices, the ELISA and the strip test could be useful tools for a rapid analysis of nortestosterone in crude extracts of dietary supplements.

scholarly journals CD4 receptor diversity in chimpanzees protects against SIV infection

2019 ◽  
Vol 116 (8) ◽  
pp. 3229-3238 ◽  
Author(s):  
Frederic Bibollet-Ruche ◽  
Ronnie M. Russell ◽  
Weimin Liu ◽  
Guillaume B. E. Stewart-Jones ◽  
Scott Sherrill-Mix ◽  
...  
Keyword(s):  
Strong Association ◽  
Glycosylation Site ◽  
Cell Entry ◽  
Site Directed Mutagenesis ◽  
Target Cells ◽  
In Silico Modeling ◽  
In The Wild ◽  
Siv Infection ◽  
Replication Fitness ◽  
Coding Variants

Human and simian immunodeficiency viruses (HIV/SIVs) use CD4 as the primary receptor to enter target cells. Here, we show that the chimpanzee CD4 is highly polymorphic, with nine coding variants present in wild populations, and that this diversity interferes with SIV envelope (Env)–CD4 interactions. Testing the replication fitness of SIVcpz strains in CD4+T cells from captive chimpanzees, we found that certain viruses were unable to infect cells from certain hosts. These differences were recapitulated in CD4 transfection assays, which revealed a strong association between CD4 genotypes and SIVcpz infection phenotypes. The most striking differences were observed for three substitutions (Q25R, Q40R, and P68T), with P68T generating a second N-linked glycosylation site (N66) in addition to an invariant N32 encoded by all chimpanzee CD4 alleles. In silico modeling and site-directed mutagenesis identified charged residues at the CD4–Env interface and clashes between CD4- and Env-encoded glycans as mechanisms of inhibition. CD4 polymorphisms also reduced Env-mediated cell entry of monkey SIVs, which was dependent on at least one D1 domain glycan. CD4 allele frequencies varied among wild chimpanzees, with high diversity in all but the western subspecies, which appeared to have undergone a selective sweep. One allele was associated with lower SIVcpz prevalence rates in the wild. These results indicate that substitutions in the D1 domain of the chimpanzee CD4 can prevent SIV cell entry. Although some SIVcpz strains have adapted to utilize these variants, CD4 diversity is maintained, protecting chimpanzees against infection with SIVcpz and other SIVs to which they are exposed.

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