Lev I et al. (2020) iScience "Germ Granules Allow Transmission of Small RNA-Based Parental Responses in the "Germ Plasm"."

Rechavi O, Lev I

[iScience, 2020]

In the recent decade small RNA-based inheritance has been implicated in a variety of transmitted physiological responses to the environment. In <i>Caenorhabditis elegans</i>, heritable small RNAs rely on RNA-dependent RNA polymerases, RNA-processing machinery, chromatin modifiers, and argonauts for their biogenesis and gene-regulatory effects. Importantly, many of these factors reside in evolutionary conserved germ granules that are required for maintaining germ cell identity and gene expression. Recent literature demonstrated that transient disturbance to the stability of the germ granules leads to changes in the pools of heritable small RNAs and the physiology of the progeny. In this piece, we discuss the heritable consequences of transient destabilization of germ granules and elaborate on the various small RNA-related processes that act in the germ granules. We further propose that germ granules may serve as environment sensors that translate environmental changes to inheritable small RNA-based responses.

Rechavi O et al. (2017) Curr Biol "Principles of Transgenerational Small RNA Inheritance in Caenorhabditis elegans."

Lev I, Rechavi O

[Curr Biol, 2017]

Examples of transgenerational inheritance of environmental responses are rapidly accumulating. In Caenorhabditis elegans nematodes, such heritable information transmits across generations in the form of RNA-dependent RNA polymerase-amplified small RNAs. Regulatory small RNAs enable sequence-specific gene regulation, and unlike chromatin modifications, can move between tissues, and escape from immediate germline reprogramming. In this review, we discuss the path that small RNAs take from the soma to the germline, and elaborate on the mechanisms that maintain or erase parental small RNA responses after a specific number of generations. We focus on the intricate interactions between heritable small RNAs and histone modifications, deposited on specific loci. A trace of heritable chromatin marks, in particular trimethylation of histone H3 lysine 9, is deposited on RNAi-targeted loci. However, how these modifications regulate RNAi or small RNA inheritance was until recently unclear. Integrating the very latest literature, we suggest that changes to histone marks may instigate transgenerational gene regulation indirectly, by affecting the biogenesis of heritable small RNAs. Inheritance of small RNAs could spread adaptive ancestral responses.

Al-Jawabreh R et al. (2024) Philos Trans R Soc Lond B Biol Sci "Advancing Strongyloides omics data: bridging the gap with Caenorhabditis elegans."

McKenzie D, Suleiman M, Hunt V, Atkinson L, Reynolds K, Lastik D, Al-Jawabreh R, Mousley A

[Philos Trans R Soc Lond B Biol Sci, 2024]

Among nematodes, the free-living model organism <i>Caenorhabditis elegans</i> boasts the most advanced portfolio of high-quality omics data. The resources available for parasitic nematodes, including <i>Strongyloides</i> spp., however, are lagging behind. While <i>C. elegans</i> remains the most tractable nematode and has significantly advanced our understanding of many facets of nematode biology, <i>C. elegans</i> is not suitable as a surrogate system for the study of parasitism and it is important that we improve the omics resources available for parasitic nematode species. Here, we review the omics data available for <i>Strongyloides</i> spp<i>.</i> and compare the available resources to those for <i>C. elegans</i> and other parasitic nematodes. The advancements in <i>C. elegans</i> omics offer a blueprint for improving omics-led research in <i>Strongyloides</i>. We suggest areas of priority for future research that will pave the way for expansions in omics resources and technologies. This article is part of the Theo Murphy meeting issue '<i>Strongyloides</i>: omics to worm-free populations'.

Seegobin SP et al. (2020) Front Neurosci "Progress in LRRK2-Associated Parkinson's Disease Animal Models."

Liang D, Choi I, Blanca Ramirez M, Yue Z, Seegobin SP, Tang B, Heaton GR

[Front Neurosci, 2020]

Mutations in the leucine-rich repeat kinase 2 (<i>LRRK2</i>) gene are the most frequent cause of familial Parkinson's disease (PD). Several genetic manipulations of the <i>LRRK2</i> gene have been developed in animal models such as rodents, <i>Drosophila</i>, <i>Caenorhabditis elegans</i>, and zebrafish. These models can help us further understand the biological function and derive potential pathological mechanisms for LRRK2. Here we discuss common phenotypic themes found in <i>LRRK2</i>-associated PD animal models, highlight several issues that should be addressed in future models, and discuss emerging areas to guide their future development.

L Singulani J et al. (2018) J Fungi (Basel) "Applications of Invertebrate Animal Models to Dimorphic Fungal Infections."

A Assato P, C de Oliveira H, Scorzoni L, M Marcos C, Fusco-Almeida AM, S Mendes-Giannini MJ, L Singulani J

[J Fungi (Basel), 2018]

Dimorphic fungi can be found in the yeast form during infection and as hyphae in the environment and are responsible for a large number of infections worldwide. Invertebrate animals have been shown to be convenient models in the study of fungal infections. These models have the advantages of being low cost, have no ethical issues, and an ease of experimentation, time-efficiency, and the possibility of using a large number of animals per experiment compared to mammalian models. Invertebrate animal models such as <i>Galleria mellonella</i>, <i>Caenorhabditis elegans</i>, and <i>Acanthamoeba</i><i>castellanii</i> have been used to study dimorphic fungal infections in the context of virulence, innate immune response, and the efficacy and toxicity of antifungal agents. In this review, we first summarize the features of these models. In this aspect, the growth temperature, genome sequence, availability of different strains, and body characteristics should be considered in the model choice. Finally, we discuss the contribution and advances of these models, with respect to dimorphic fungi <i>Paracoccidioides</i> spp., <i>Histoplasma capsulatum</i>, <i>Blastomyces dermatitidis</i>, <i>Sporothrix</i> spp., and <i>Talaromyces marneffei (Penicillium marneffei)</i>.

Merrin J (2019) Bioengineering (Basel) "Frontiers in Microfluidics, a Teaching Resource Review."

Merrin J

[Bioengineering (Basel), 2019]

This is a literature teaching resource review for biologically inspired microfluidics courses or exploring the diverse applications of microfluidics. The structure is around key papers and model organisms. While courses gradually change over time, a focus remains on understanding how microfluidics has developed as well as what it can and cannot do for researchers. As a primary starting point, we cover micro-fluid mechanics principles and microfabrication of devices. A variety of applications are discussed using model prokaryotic and eukaryotic organisms from the set of bacteria (<i>Escherichia coli</i>), trypanosomes (<i>Trypanosoma brucei</i>), yeast (<i>Saccharomyces cerevisiae</i>), slime molds (<i>Physarum polycephalum</i>), worms (<i>Caenorhabditis elegans</i>), flies (<i>Drosophila melangoster</i>), plants (<i>Arabidopsis thaliana</i>), and mouse immune cells (<i>Mus musculus</i>). Other engineering and biochemical methods discussed include biomimetics, organ on a chip, inkjet, droplet microfluidics, biotic games, and diagnostics. While we have not yet reached the end-all lab on a chip, microfluidics can still be used effectively for specific applications.

Topf U et al. (2019) Front Neurosci "Ancient Function of Teneurins in Tissue Organization and Neuronal Guidance in the Nematode Caenorhabditis elegans."

Drabikowski K, Topf U

[Front Neurosci, 2019]

The nematode <i>Caenorhabditis elegans</i> expresses the <i>ten-1</i> gene that encodes teneurin. TEN-1 protein is expressed throughout the life of <i>C. elegans</i>. The loss of <i>ten-1</i> function results in embryonic and larval lethality, highlighting its importance for fundamental processes during development. TEN-1 is expressed in the epidermis and neurons. Defects in neuronal pathfinding and epidermal closure are characteristic of <i>ten-1</i> loss-of-function mutations. The molecular mechanisms of TEN-1 function in neurite outgrowth, neuronal pathfinding, and dendritic morphology in <i>C. elegans</i> are largely unknown. Its genetic redundancy with the extracellular matrix receptors integrin and dystroglycan and genetic interactions with several basement membrane components suggest a role for TEN-1 in the maintenance of basement membrane integrity, which is essential for neuronal guidance. Identification of the <i>lat-1</i> gene in <i>C. elegans</i>, which encodes latrophilin, as an interaction partner of <i>ten-1</i> provides further mechanistic insights into TEN-1 function in neuronal development. However, receptor-ligand interactions between LAT-1 and TEN-1 remain to be experimentally proven. The present review discusses the function of teneurin in <i>C. elegans</i>, with a focus on its involvement in the formation of receptor signaling complexes and neuronal networks.

Torres M et al. (2020) J Fungi (Basel) "In Vitro or In Vivo Models, the Next Frontier for Unraveling Interactions between Malassezia spp. and Hosts. How Much Do We Know?"

Celis Ramirez AM, Torres M, de Cock H

[J Fungi (Basel), 2020]

<i>Malassezia</i> is a lipid-dependent genus of yeasts known for being an important part of the skin mycobiota. These yeasts have been associated with the development of skin disorders and cataloged as a causal agent of systemic infections under specific conditions, making them opportunistic pathogens. Little is known about the host-microbe interactions of <i>Malassezia</i> spp., and unraveling this implies the implementation of infection models. In this mini review, we present different models that have been implemented in fungal infections studies with greater attention to <i>Malassezia</i> spp. infections. These models range from in vitro (cell cultures and ex vivo tissue), to in vivo (murine models, rabbits, guinea pigs, insects, nematodes, and amoebas). We additionally highlight the alternative models that reduce the use of mammals as model organisms, which have been gaining importance in the study of fungal host-microbe interactions. This is due to the fact that these systems have been shown to have reliable results, which correlate with those obtained from mammalian models. Examples of alternative models are <i>Caenorhabditis elegans</i>, <i>Drosophila melanogaster</i>, <i>Tenebrio molitor</i>, and <i>Galleria mellonella</i>. These are invertebrates that have been implemented in the study of <i>Malassezia</i> spp. infections in order to identify differences in virulence between <i>Malassezia</i> species.

Yue Y et al. (2021) Curr Res Food Sci "Caenorhabditis elegans as a model for obesity research."

Park Y, Yue Y, Li S, Shen P

[Curr Res Food Sci, 2021]

<i>Caenorhabditis elegans</i>, a free-living nematode, is an animal model that has been extensively employed in a variety of research fields, including in the study of obesity. Its favorable features include its compact size, short life cycle, large brood size, easy handling, low cost, availability of complete genetic information, 65% conserved human diseases-associated genes, relatively easy genetic manipulation, and research using <i>Caenorhabditis elegans</i> does not require approvals by the Institutional Animal Care and Use Committee. These advantages make <i>Caenorhabditis elegans</i> a great <i>in vivo</i> model for life science research including obesity research. In this review, we provide graphic overviews of <i>Caenorhabditis elegans'</i> basic anatomy, growth conditions, routes of compound delivery, and fat metabolism, both synthesis and degradation pathways, including major signaling pathways involved. Our aim is to provide an overview for researchers interested in applying <i>C. elegans</i> as an <i>in vivo</i> model for the screening and identification of anti-obesity bioactive compounds prior to testing in vertebrate animal models.

Wu CY et al. (2024) Int J Mol Sci "Caenorhabditis elegans as a Convenient Animal Model for Microbiome Studies."

Yang HC, Davis S, Zhao W, Martel J, Ojcius D, Stern A, Shah S, Saudagar N, Wu CY

[Int J Mol Sci, 2024]

Microbes constitute the most prevalent life form on Earth, yet their remarkable diversity remains mostly unrecognized. Microbial diversity in vertebrate models presents a significant challenge for investigating host-microbiome interactions. The model organism <i>Caenorhabditis elegans</i> has many advantages for delineating the effects of host genetics on microbial composition. In the wild, the <i>C. elegans</i> gut contains various microbial species, while in the laboratory it is usually a host for a single bacterial species. There is a potential host-microbe interaction between microbial metabolites, drugs, and <i>C. elegans</i> phenotypes. This mini-review aims to summarize the current understanding regarding the microbiome in <i>C. elegans</i>. Examples using <i>C. elegans</i> to study host-microbe-metabolite interactions are discussed.