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Nematologica,
1976]
The growth promoting activity of protein-haemin co-precipitates from ferritin, apoferritin, transferrin, bovine serum albumin, conalbumin and egg white on maturation and reproduction of C. briggsae has been evaluated. Ferritin, apoferritin and transferrin were found to be biologically highly active in the presence of haemin. Bovine serum albumin, conalbumin and egg white were slightly active. Maturation and reproduction of C. briggsae on the coagulates from bovine serum albumin and egg white were nearly independent of the dose administered, probably because the limited availability of haemin from these coagulates permits but slow growth, even in the presence of abundant proteinaceous material. Bovine serum albumin, egg white and conalbumin failed to support continuous growth of C. briggsae. It is supposed that the limited availability of haemin from these coagulates inhibits normal maturation and reproduction of the F1 progeny. These experiments clearly demonstrate the requirement for particulate haem. The requirement for
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Microsc Microanal,
2014]
A variety of specimens including bacteria, ciliates, choanoflagellates (Salpingoeca rosetta), zebrafish (Danio rerio) embryos, nematode worms (Caenorhabditis elegans), and leaves of white clover (Trifolium repens) plants were high pressure frozen, freeze-substituted, infiltrated with either Epon, Epon-Araldite, or LR White resins, and polymerized. Total processing time from freezing to blocks ready to section was about 6 h. For epoxy embedding the specimens were freeze-substituted in 1% osmium tetroxide plus 0.1% uranyl acetate in acetone. For embedding in LR White the freeze-substitution medium was 0.2% uranyl acetate in acetone. Rapid infiltration was achieved by centrifugation through increasing concentrations of resin followed by polymerization at 100C for 1.5-2 h. The preservation of ultrastructure was comparable to standard freeze substitution and resin embedding methods that take days to complete. On-section immunolabeling results for actin and tubulin molecules were positive with very low background labeling. The LR White methods offer a safer, quicker, and less-expensive alternative to Lowicryl embedding of specimens processed for on-section immunolabeling without traditional aldehyde fixatives.
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Valansi C, Zeev-Ben-Mordehai T, Grunewald K, White JM, Maurer UE, Avinoam O, Abutbul I, Fridman K, Podbilewicz B, Danino D, Sapir A
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Science,
2011]
Caenorhabditis elegans proteins AFF-1 and EFF-1 [C. elegans fusion family (CeFF) proteins] are essential for developmental cell-to-cell fusion and can merge insect cells. To study the structure and function of AFF-1, we constructed vesicular stomatitis virus (VSV) displaying AFF-1 on the viral envelope, substituting the native fusogen VSV glycoprotein. Electron microscopy and tomography revealed that AFF-1 formed distinct supercomplexes resembling pentameric and hexameric "flowers" on pseudoviruses. Viruses carrying AFF-1 infected mammalian cells only when CeFFs were on the target cell surface. Furthermore, we identified fusion family (FF) proteins within and beyond nematodes, and divergent members from the human parasitic nematode Trichinella spiralis and the chordate Branchiostoma floridae could also fuse mammalian cells. Thus, FF proteins are part of an ancient family of cellular fusogens that can promote fusion when expressed on a viral particle.
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J Environ Sci Health A Tox Hazard Subst Environ Eng,
2017]
This study aimed to investigate the biological impact of exposure on domestic light emitting diodes (LED) lighting using the free-living nematode Caenorhabditis elegans as a model. Nematodes were separately exposed to white LED light covering the range of 380-750nm, blue light at 450nm and black light at 380-420nm for one life cycle (egg to adult) with dark exposure as the control. Each light range induced stress to the nematode C. elegans such as reducing the number of the hatched eggs and/or delayed the maturation of the hatched eggs to the adult stage. In addition, it lowered or prevented the ability of adults to lay eggs and impaired the locomotion in the exposed worms. The observed type of biological stress was also associated with the production of reactive oxygen species (ROS) as compared to nematodes grown in the dark. It is concluded that the blue light component of white LED light may cause health problems, and further investigation is required to test commercial brands of white LEDs that emit different amounts of blue light.
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Neuron,
2002]
Drosophila melanogaster has been a premier genetic model system for nearly 100 years, yet lacks a simple method to disrupt gene expression. Here, we show genomic cDNA fusions predicted to form double-stranded RNA (dsRNA) following splicing, effectively silencing expression of target genes in adult transgenic animals. We targeted three Drosophila genes: lush, white, and dGqalpha. In each case, target gene expression is dramatically reduced, and the white RNAi phenotype is indistinguishable from a deletion mutant. This technique efficiently targets genes expressed in neurons, a tissue refractory to RNAi in C. elegans. These results demonstrate a simple strategy to knock out gene function in specific cells in living adult Drosophila that can be applied to define the biological function of hundreds of orphan genes and open reading frames.
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Nucleic Acids Res,
2020]
Single mRNA molecules are frequently detected by single molecule fluorescence in situ hybridization (smFISH) using branched DNA technology. While providing strong and background-reduced signals, the method is inefficient in detecting mRNAs within dense structures, in monitoring mRNA compactness and in quantifying abundant mRNAs. To overcome these limitations, we have hybridized slices of high pressure frozen, freeze-substituted and LR White embedded cells (LR White smFISH). mRNA detection is physically restricted to the surface of the resin. This enables single molecule detection of RNAs with accuracy comparable to RNA sequencing, irrespective of their abundance, while at the same time providing spatial information on RNA localization that can be complemented with immunofluorescence and electron microscopy, as well as array tomography. Moreover, LR White embedding restricts the number of available probe pair recognition sites for each mRNA to a small subset. As a consequence, differences in signal intensities between RNA populations reflect differences in RNA structures, and we show that the method can be employed to determine mRNA compactness. We apply the method to answer some outstanding questions related to trans-splicing, RNA granules and mitochondrial RNA editing in single-cellular trypanosomes and we show an example of differential gene expression in the metazoan Caenorhabditis elegans.
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J Hand Surg Am,
1980]
A 36-year-old white male schoolteacher presented with a painless, semifluctuant mass on the volar aspect of his forearm and symptoms of ring finger tenosynovitis and median nerve compression. At operation there was a widespread infestation of the flexor tendon compartment, the carpal tunnel, and the tendon sheaths of the ringer finger with Onchocerca volvulus, a filarial nematode, not previously reported in the these tissues.
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Biofouling,
2015]
The emergence of antibiotic resistant Staphylococcus aureus presents a worldwide problem that requires non-antibiotic strategies. This study investigated the anti-biofilm and anti-hemolytic activities of four red wines and two white wines against three S. aureus strains. All red wines at 0.5-2% significantly inhibited S. aureus biofilm formation and hemolysis by S. aureus, whereas the two white wines had no effect. Furthermore, at these concentrations, red wines did not affect bacterial growth. Analyses of hemolysis and active component identification in red wines revealed that the anti-biofilm compounds and anti-hemolytic compounds largely responsible were tannic acid, trans-resveratrol, and several flavonoids. In addition, red wines attenuated S. aureus virulence in vivo in the nematode Caenorhabditis elegans, which is killed by S. aureus. These findings show that red wines and their compounds warrant further attention in antivirulence strategies against persistent S. aureus infection.
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Methods Mol Biol,
2015]
The C. elegans dauer is an attractive model with which to investigate fundamental biological questions, such as how environmental cues are sensed and are translated into developmental decisions through a series of signaling cascades that ultimately result in a transformed animal. Here we describe a simple method of using egg white plates to obtain highly synchronized purified dauers that can be used in downstream applications requiring large quantities of dauers or postdauer animals.
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Trends Neurosci,
2018]
Large-scale efforts are underway to map the neuronal connectomes of various animal species. In 1986 White et al. reported the first complete reconstruction of the nervous system connectome of an animal. Largely through manual reconstruction of serial electron micrographs, the authors characterized the morphology of each of the 302 neurons of the adult nematode C. elegans, and mapped the chemical and electrical synapses that connect them. This wiring diagram has profoundly influenced behavioral neurobiology and network science, and it continues to offer a guide for the impact of connectomics on neurobiology.