We examined the role of Delta signaling in specification of two derivatives in zebrafish neural plate: Rohon-Beard spinal sensory neurons and neural crest. deltaA-expressing Rohon-Beard neurons are intermingled with premigratory neural crest cells in the trunk lateral neural plate. Embryos homozygous for a point mutation in deltaA, or with experimentally reduced delta signalling, have supernume...

Dr. Andrew’s proposal (Andrew, 2013) to rename Guyton’s venous return curve the ‘venous pressure curve’ seems unlikely to overcome the decades of misinterpretation and confusion that the Guytonmodel of the systemic circulation has engendered. In Guyton’s experiments venous return curves were produced with a pump connected from the right atrium to the pulmonary artery in an anaesthetized, open c...

In zebrafish, cells at the lateral edge of the neural plate become Rohon-Beard primary sensory neurons or neural crest. Delta/Notch signaling is required for neural crest formation. ngn1 is expressed in primary neurons; inhibiting Ngn1 activity prevents Rohon-Beard cell formation but not formation of other primary neurons. Reducing Ngn1 activity in embryos lacking Delta/Notch signaling restores...

Data from smallholder flocks of adult West African Dwarf (WAD) and Red Sokoto goats (n = 824) and Yankasa, Uda and Balami sheep (n = 636) were utilized to investigate the distribution and frequencies of certain qualitative traits. The animals were randomly sampled in Northern parts of Nigeria. They were scored for the presence or absence of wattle, beard, horn, coat colour [Phaeomelanic standar...

The trunk and tail skin of Xenopus laevis embryos near the time of hatching is innervated by the mechanoreceptive free nerve endings of Rohon-Beard neurons, a homogeneous class of cutaneous primary afferent fibers. Rohon-Beard neurons have cell bodies and axons in the dorsal spinal cord, where they monosynaptically excite a population of dorsolaterally situated interneurons (Clarke and Roberts,...