Tol2 transposon-mediated transgenesis in the Midas cichlid (Amphilophus citrinellus) — towards understanding gene function and regulatory evolution in an ecological model system for rapid phenotypic diversification

The present paper investigates the influence of environmental noise on a fairly realistic three-species food chain model based on the Leslie-Gower scheme. The self- growth parameter for the prey species is assumed to be perturbed by white noise characterized by a Gaussian distribution with mean zero and unit spectral density. Using tools borrowed from the nonlinear dynamical system theory, we study the dynamical behavior of the model system. The behavior of the stochastic system (perturbed one) is studied and the fluctuations in the populations are measured both analytically (for the linearized system) and numerically by computer simulation. Varying one of the control parameters in its range, while keeping all the others constant, we monitor the changes in the dynamical behavior of the model system, thereby fixing the regimes in which the system exhibits chaotic dynamics. Our study suggests that the trophic level (top, middle or bottom) at which a population is positioned, the amplitude of environmental noise and the population's susceptibility to environmental noise play key roles in how noise affects the population dynamics.

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Functional genomics in the wild: a case study with paper wasps shows challenges and prospects for RNA interference in ecological systems

Genome ◽

10.1139/gen-2017-0066 ◽

2018 ◽

Vol 61 (4) ◽

pp. 266-272 ◽

Cited By ~ 2

Author(s):

S.A. Weiner ◽

A.G. Geffre ◽

A.L. Toth

Keyword(s):

Rna Interference ◽

Functional Genomics ◽

Gene Function ◽

Ecological Model ◽

Model Organisms ◽

Natural Environments ◽

Paper Wasps ◽

Fatty Acid Binding ◽

In The Wild

RNA interference (RNAi) is a useful tool to assess gene function by knocking down expression of a target gene and has been used successfully in domestic and laboratory organisms. However, the use of RNAi for functional genomics has not fully extended into ecological model organisms in natural environments. Assessment of gene function in the wild is important because gene function can be environmentally and context dependent. Here, we present a case study using RNAi to assess gene function in wild paper wasps Polistes metricus, to test roles for two candidate genes (NADH dehydrogenase (NADHdh) and retinoid and fatty acid binding protein (RfaBp)) in the development of reproductive castes. Previous studies have shown that these genes are upregulated in larvae that become queens compared to workers, but this pattern was reversed in the laboratory, making field-based studies necessary. We orally administered dsRNA to larvae in field colonies and found evidence of a short-term knockdown followed by a compensatory rebound in expression for RfaBp. We also observed the predicted worker-like decrease in lipid stores in NADHdh dsRNA treated wasps, suggesting a possible role for NADHdh in caste development. We discuss our results in the context of challenges for using RNAi for functional genomics in ecological model organisms in the field.

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CRISPR/Cas9-Mediated Mutagenesis of RCO in Cardamine hirsuta

Plants ◽

10.3390/plants9020268 ◽

2020 ◽

Vol 9 (2) ◽

pp. 268

Author(s):

Claire Lessa Alvim Kamei ◽

Bjorn Pieper ◽

Stefan Laurent ◽

Miltos Tsiantis ◽

Peter Huijser

Keyword(s):

Arabidopsis Thaliana ◽

Genome Editing ◽

Gene Function ◽

Comparative Studies ◽

Model System ◽

Reference Plant ◽

Novel Alleles ◽

Plant Arabidopsis Thaliana

The small crucifer Cardamine hirsuta bears complex leaves divided into leaflets. This is in contrast to its relative, the reference plant Arabidopsis thaliana, which has simple leaves. Comparative studies between these species provide attractive opportunities to study the diversification of form. Here, we report on the implementation of the CRISPR/Cas9 genome editing methodology in C. hirsuta and with it the generation of novel alleles in the RCO gene, which was previously shown to play a major role in the diversification of form between the two species. Thus, genome editing can now be deployed in C. hirsuta, thereby increasing its versatility as a model system to study gene function and evolution.

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Sperm Morphology and Male Age in Black-Throated Blue Warblers, an Ecological Model System

Animals ◽

10.3390/ani10071175 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1175

Author(s):

Emily Cramer ◽

Nicole Krauss ◽

Tricia Rowlison ◽

Pierre Comizzoli

Keyword(s):

Sperm Morphology ◽

Ecological Model ◽

Model Species ◽

Male Age ◽

Extra Pair Paternity ◽

Male Phenotype ◽

Status Signal ◽

Paternity Success ◽

Ecological Model System ◽

Older Males

Extra-pair paternity may drive selection on spermatozoa and ejaculate characteristics through sperm competition and cryptic female choice. Here, we examine sperm morphology in the black-throated blue warbler (Setophaga caerulescens), an ecological model species where extra-pair paternity is frequent and is linked with male age. We test whether sperm morphology relates to several aspects of male phenotype known or suspected to affect extra-pair paternity success. Sperm morphology did not correlate with the size of the white wing spot, a social status signal, nor with the volume of the cloacal protuberance. However, older males tended to have longer sperm cells. Although the sample size was limited, this pattern is intriguing, as longer cells may be advantageous in post-copulatory sexual selection and older males have larger testes and higher extra-pair paternity success in this species. Changes in sperm morphology with age are not observed in other birds, though they have been observed in insects and fishes. More research on sperm morphology is needed to clarify its role in extra-pair fertilizations in this well-studied species.

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A Protozoan Model for Golgi-Associated Calcification

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065705 ◽

1971 ◽

Vol 29 ◽

pp. 332-333

Author(s):

D. C. Williams ◽

D. E. Outka

Keyword(s):

Golgi Apparatus ◽

Organic Matrix ◽

Model System ◽

Sequential Formation

Many studies have shown that the Golgi apparatus is involved in a variety of synthetic activities, and probably no Golgi product is more elaborate than the scales produced by various kinds of phytoflagellates. The formation of calcified scales (coccoliths, Fig. 1,2) of the coccolithophorid phytoflagellates provides a particularly interesting model system for the study of biological mineralization, and the sequential formation of Golgi products.The coccoliths of Hymenomonas carterae consist of a scale-like base (Fig. 2 and 4, b) with a highly structured calcified (CaCO3) rim composed of two distinct elements which alternate about the base periphery (Fig. 1 and 3, A, B). Each element is enveloped by a sheath-like organic matrix (Fig. 3; Fig. 4, m).

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Existence of DNA in yeast microbodies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082029 ◽

1978 ◽

Vol 36 (2) ◽

pp. 232-233

Author(s):

Masako Osumi ◽

Misuzu Nagano ◽

Hiroko Kazama

Keyword(s):

Catalase Activity ◽

Buoyant Density ◽

Model System ◽

Contour Length ◽

Native State ◽

Normal Alkane ◽

Remarkable Increase ◽

Dna Molecule ◽

Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

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The coprecipitation of Cr3P and Cr in Cu

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105886 ◽

1988 ◽

Vol 46 ◽

pp. 764-765

Author(s):

M.J. Witcomb ◽

U. Dahmen ◽

K.H. Westmacott

Keyword(s):

Orientation Relationship ◽

Interface Structure ◽

Model System ◽

Relative Orientation ◽

Age Hardening ◽

Precipitation Behavior ◽

Solution Treated ◽

Small Needle ◽

Diffraction Patterns ◽

Interface Structures

Cu-Cr age-hardening alloys are of interest as a model system for the investigation of fcc/bcc interface structures. Several past studies have investigated the morphology and interface structure of Cr precipitates in a Cu matrix (1-3) and good success has been achieved in understanding the crystallography and strain contrast of small needle-shaped precipitates. The present study investigates the effect of small amounts of phosphorous on the precipitation behavior of Cu-Cr alloys.The same Cu-0.3% Cr alloy as was used in earlier work was rolled to a thickness of 150 μm, solution treated in vacuum at 1050°C for 1h followed by quenching and annealing for various times at 820 and 863°C.Two laths and their corresponding diffraction patterns in an alloy aged 2h at 820°C are shown in correct relative orientation in Fig. 1. To within the limit of accuracy of the diffraction patterns the orientation relationship was that of Kurdjumov-Sachs (KS), i.e. parallel close-packed planes and directions.

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