White J (2018) Philos Trans R Soc Lond B Biol Sci "Clues to basis of exploratory behaviour of the C. elegans snout from head somatotropy."

White J

[Philos Trans R Soc Lond B Biol Sci, 2018]

Wave propagation during locomotory movements of <i>Caenorhabditis elegans</i> is constrained to a single dorso/ventral plane. By contrast, the tip of the head (snout) can make rapid exploratory movements in all directions relative to the body axis. These extra degrees of freedom are probably important for animals to seek and identify desirable passages in the interstices of the three-dimensional matrix of soil particles, their usual habitat. The differences in degrees of freedom of movement between snout and body are reflected in the innervation of the musculature. Along the length of the body, the two quadrants of dorsal muscle receive common innervation as do the two quadrants of ventral muscle. By contrast, muscles in the snout have an octagonal arrangement of innervation. It is likely that the exploratory behaviour of the snout is mediated by octant-specific motor and sensory neurons, together with their associated interneurons. The well-defined anatomical structure and neural circuitry of the snout together with behavioural observations should facilitate the implementation of models of the neural basis of exploratory movements, which could lead to an understanding of the basis of this relatively complex behaviour, a behaviour that has similarities to foraging in some vertebrates.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling <i>C. elegans</i> at cellular resolution'.

White-Cooper H et al. (2010) Philos Trans R Soc Lond B Biol Sci "Evolution and spermatogenesis."

White-Cooper H, Bausek N

[Philos Trans R Soc Lond B Biol Sci, 2010]

Sexual reproduction depends on the production of haploid gametes, and their fusion to form diploid zygotes. Here, we discuss sperm production and function in a molecular and functional evolutionary context, drawing predominantly from studies in model organisms (mice, Drosophila, Caenorhabditis elegans). We consider the mechanisms involved in establishing and maintaining a germline stem cell population in testes, as well as the factors that regulate their contribution to the pool of differentiating cells. These processes involve considerable interaction between the germline and the soma, and we focus on regulatory signalling events in a variety of organisms. The male germline has a unique transcriptional profile, including expression of many testis-specific genes. The evolutionary pressures associated with gene duplication and acquisition of testis function are discussed in the context of genome organization and transcriptional regulation. Post-meiotic differentiation of spermatids involves very dramatic changes in cell shape and acquisition of highly specialized features. We discuss the variety of sperm motility mechanisms and how various reproductive strategies are associated with the diversity of sperm forms found in animals.

White JG et al. (1991) Philos Trans R Soc Lond B Biol Sci "On the nature of undead cells in the nematode Caenorhabditis elegans."

Thomson JN, White JG, Southgate E

[Philos Trans R Soc Lond B Biol Sci, 1991]

During the course of normal embryonic and post-embryonic development, 131 cells in a Caenorhabditis elegans hermaphrodite undergo programmed cell death. Loss of function mutations in either of the genes ced-3 or ced-4 abolish cell deaths, enabling these 'undead' cells to survive and be incorporated into the adult with no obvious deleterious consequences. Ultrastructural reconstructions have shown that the undead cells exhibit many differentiated characteristics. Most of the reconstructed cells appear to be neurons wit all the characterisic features associated with such cells, such as processes, synaptic vesicles and pre-synaptic specializations. However, clear morphological differences were seen among the undead neurons, suggesting a diversity of cell type. One of the reconstructed cells was a rectal epithelial cell, which had displaced its lineal sister that normally functions in this role. Removal of the ability to undergo programmed cell death by mutation therefore reveals a diversity of cryptic differentiated states that are acquired by cells that normally are destined to die.

White JG et al. (1976) Philos Trans R Soc Lond B Biol Sci "The structure of the ventral nerve cord of Caenorhabditis elegans."

Brenner S, White JG, Thomson JN, Southgate E

[Philos Trans R Soc Lond B Biol Sci, 1976]

The nervous system of Caenorhabditis elegans is arranged as a series of fibre bundles which run along internal hypodermal ridges. Most of the sensory integration takes place in a ring of nerve fibres which is wrapped round the pharynx in the head. The body muscles in the head are innervated by motor neurones in this nerve ring while those in the lower part of the body are innervated by a set of motor neurones in a longitudinal fibre bundle which joins the nerve ring, the ventral cord. These motor neurones can be put into five classes on the basis of their morphology and synaptic input. At any one point along the cord only one member from each class has neuromuscular junctions. Members of a given class are arranged in a regular linear sequence in the cord and have non-overlapping fields of motor synaptic activity, the transition between fields of adjacent neurones being sharp and well defined. Members of a given class form gap junctions with neighbouring members of the same class but never to motor neurones of another class. Three of the motor neurone classes receive their synaptic input from a set of interneurones coming from the nerve ring. These interneurones can in turn be grouped into four classes and each of the three motor neurone classes receives its synaptic input from a unique combination of interneurone classes. The possible developmental and functional significance of these

White JG et al. (1986) Philos Trans R Soc Lond B Biol Sci "The structure of the nervous system of the nematode Caenorhabditis elegans."

White JG, Southgate E, Thomson JN, Brenner S

[Philos Trans R Soc Lond B Biol Sci, 1986]

The structure and connectivity of the nervous system of the nematode Caenorhabditis elegans has been deduced from reconstructions of electron micrographs of serial sections. The hermaphrodite nervous system has a total complement of 302 neurons, which are arranged in an essentially invariant structure. Neurons with similar morphologies and connectivities have been grouped together into classes; there are 118 such classes. Neurons have simple morphologies with few, if any, branches. Processes from neurons run in defined positions within bundles of parallel processes, synaptic connections being made en passant. Process bundles are arranged longitudinally and circumferentially and are often adjacent to ridges of hypodermis. Neurons are generally highly locally connected, making synaptic connections with many of their neighbours. Muscle cells have arms that run out to process bundles containing motoneuron axons. Here they receive their synaptic input in defined regions along the surface of the bundles, where motoneuron axons reside. Most of the morphologically identifiable synaptic connections in a typical animal are described. These consist of about 5000 chemical synapses, 2000 neuromuscular junctions and 600 gap junctions.

Galindo-Malagn XA et al. (2022) Zootaxa "New species, synonymies and records in the genus Rhagovelia Mayr, 1865 (Hemiptera: Heteroptera: Veliidae) from Colombia."

Moreira FFF, Morales I, Mondragn-F SP, Galindo-Malagn XA

[Zootaxa, 2022]

Rhagovelia medinae sp. nov., of the hambletoni group (angustipes complex), and R. utria sp. nov., of the hirtipes group (robusta complex), are described, illustrated, and compared with similar congeners. Based on the examination of type specimens, six new synonymies are proposed: R. elegans Uhler, 1894 = R. pediformis Padilla-Gil, 2010, syn. nov.; R. cauca Polhemus, 1997 = R. azulita Padilla-Gil, 2009, syn. nov., R. huila Padilla-Gil, 2009, syn. nov., R. oporapa Padilla-Gil, 2009, syn. nov, R. quilichaensis Padilla-Gil, 2011, syn. nov.; and R. gaigei, Drake Hussey, 1947 = R. victoria Padilla-Gil, 2012 syn. nov. The first record from Colombia is presented for R. trailii (White, 1879), and the distributions of the following species are extended in the country: R. cali Polhemus, 1997, R. castanea Gould, 1931, R. cauca Polhemus, 1997, R. gaigei Drake Hussey, 1957, R. elegans Uhler, 1894, R. femoralis Champion, 1898, R. malkini Polhemus, 1997, R. perija Polhemus, 1997, R. sinuata Gould, 1931, R. venezuelana Polhemus, 1997, R. williamsi Gould, 1931, and R. zeteki Drake, 1953.

Blumenthal TE et al. (1993) Worm Breeder's Gazette "The C. elegans Cleavage and Polyadenylation Signal"

Fields CA, White O, Blumenthal TE

[Worm Breeder's Gazette, 1993]

THE C. ELEGANS CLEAVAGE AND POLYADENYLATION SlGNAL Tom Blumenthal, Department of Biology, Indiana University. Bloomington, IN 47405; Owen White and Chris Fields, Institute For Genomic Research, Gaithersburg, MD, 20878

Vanfleteren JR (1976) Nematologica "The nature of a nematode growth factor. III. Growth and maturation of C. briggsae on protein-haemin co-precipitates."

Vanfleteren JR

[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

Hobert O et al. (1999) Worm Breeder's Gazette "Neuroanatomy-- A second look with GFP reporters and some comments"

Hobert O, Hall DH

[Worm Breeder's Gazette, 1999]

For everyone who deals with the characterization of expression patterns in the nervous system, the truly impressive paper of White et al., 1986 ("Mind of the Worm") serves as the ultimate source of knowledge. While the largely invariant neural cell body positions described by Sulston et al. are an essential tool in the identification of neurons, the axon morphologies described by White et al. greatly facilitate the identification of a given neuron.

McDonald KL (2014) Microsc Microanal "Rapid embedding methods into epoxy and LR White resins for morphological and immunological analysis of cryofixed biological specimens."

McDonald KL

[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.