The genus Atheris (Serpentes: Viperidae) in East Africa: phylogeny and the role of rifting and climate in shaping the current pattern of species diversity.

Past climatic and tectonic events are believed to have strongly influenced species diversity in the Eastern Afromontane Biodiversity Hotspot. We investigated the phylogenetic relationships and historical biogeography of the East African genus Atheris (Serpentes: Viperidae), and explored temporal and spatial relationships between Atheris species across Africa, and the impact of palaeoclimatic fluctuations and tectonic movements on cladogenesis of the genus. Using mitochondrial sequence data, the phylogeny of East African species of Atheris shows congruent temporal patterns that link diversification to major tectonic and aridification events within East Africa over the last 15million years (my). Our results are consistent with a scenario of a delayed direct west-east colonisation of the Eastern Arc Mountains of Atheris by the formation of the western rift. Based on the phylogenetic patterns, this terrestrial, forest-associated genus has dispersed into East Africa across a divided route, on both west-southeasterly and west-northeasterly directions (a C-shaped route). Cladogenesis in the Eastern Arc Mountains and Southern Highlands of Tanzania corresponds to late Miocene and Plio-Pleistocene climatic shifts. Taxonomically, our data confirmed the monophyly of Atheris as currently defined, and reveal four major East African clades, three of which occur in discrete mountain ranges. Possible cryptic taxa are identified in the Atheris rungweensis and A. ceratophora clades.

Conserving large populations of lions - the argument for fences has holes.

Packer et al. reported that fenced lion populations attain densities closer to carrying capacity than unfenced populations. However, fenced populations are often maintained above carrying capacity, and most are small. Many more lions are conserved per dollar invested in unfenced ecosystems, which avoid the ecological and economic costs of fencing.

The detection of AKH/HrTH-like peptides in Ascaridia galli and Ascaris suum using an insect hyperglycaemic bioassay.

Evidence for the presence of adipokinetic hormone/hypertrehalosaemic hormone (AKH/HrTH)-like peptides in the parasitic nematodes Ascaridia galli and Ascaris suum has been obtained using insect bioassays which measure hyperglycaemic responses to peptides belonging to the AKH/HrTH family of insect hormones. A peptide fraction extracted from heads and tails of Ascaridia galli evoked a dose-dependent hyperglycaemic response when injected into the cockroach, Periplaneta americana. Maximal bioactivity was obtained with material that was equivalent to 38 mg (wet weight) of nematode. Bioactivity appeared to be highest in extracts from heads and tails of both male and female worms and could be fractionated into at least three peaks of hyperglycaemic activity by reversed-phase high-performance liquid chromatography. An extract from heads and tails of A. suum also evoked a hyperglycaemic response when injected into the cockroach, Blaberus discoidalis. The bioactivity was inactivated on incubation with pure endopeptidase 24.11, confirming the peptidic nature of the bioactive material. These results provide evidence for the existence of peptides related to the insect AKH/HrTH family of peptides in parasitic nematodes.

The presence of peptides related to the adipokinetic hormone/red pigment-concentrating hormone family in the nematode, Panagrellus redivivus.

Immunocytochemistry using polyclonal antisera raised to fragments or derivatives of locust adipokinetic hormone (AKH) I and IIs (Schooneveld et al., 1983, 1985, 1986) selectively stained cells in the nervous system of the free-living nematode, Panagrellus redivivus. Antiserum 528 (raised to the C-terminus of AKH IIs) stained the dorsal cephalic papillary cell bodies and the anterior nerve ring. Fibres in the lateral cords were stained with antiserum 241 that recognises the C-terminus of AKH I. Substances reacting to antisera 433 (raised to the N-terminal sequence of AKH I and IIs) 528 and 241 were present in the preanal ganglion and associated ventral nerve fibres. In males, all three antisera stained fibres leading to the base of the spicules. A peptide fraction from whole P. redivivus evoked an adipokinetic response in the locust, Schistocera gregaria which was dose dependent and was abolished by treatment with endopeptidase 24:11 but not by boiling or by incubation with leucine aminopeptidase. The adipokinetic activity was reduced by over 70% on incubation of the peptide fraction with pyroglutamyl aminopeptidase. The same fraction induced hyperglycaemia when injected into the cockroach, Periplaneta americana. These results are consistent with the existence in P. redivivus of peptides that are structurally related to the arthropod adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family.

Immunocytochemical demonstration of a neuropeptide in Ascaris suum (Nematoda) using an antiserum to FMRFamide.

A FMRFamide-like peptide has been detected in the nematode Ascaris suum, using the peroxidase-anti-peroxidase (PAP) immunocytochemical technique. Positive reactions were obtained in both the central nervous system and the peripheral nervous system of the worm, the strongest reactions being in the anterior nerve ring, the cephalic papillary ganglia, the lateral ganglia and the dorso-rectal ganglion. Immunoreactivity was observed along the length of the main nerve cords of the worm and, to a lesser extent, in the pharyngeal nerve cords. The possible role of this neuropeptide in the physiology of the nematode is discussed.

FMRFamide-like immunoreactivity and arylamidase activity in turbellarians and nemerteans--evidence for a novel neurovascular coordinating system in nemerteans.

The tetrapeptide Phe-Met-Arg-Phe-NH2 (FMRFamide) has been immunolocalized in the nervous systems of seven species of Turbellaria and four species of Nemertea. The 11 species represent all the major turbellarian and nemertean taxa, and illustrate most of the various life styles found in these animals. The FMRFamide-like reactivity coincides with histochemically demonstrable arylamidase activity in the nervous systems. It is suggested that the FMRFamide-like reactivity demonstrates the presence in these lower invertebrates of one or more biologically active peptides, analogous to those of higher invertebrates and chordates and acting as putative neurotransmitters and coordinators of growth, maturation and muscular activities. The arylamidases occurring with the peptides are probably an integral part of these peptide-mediated control systems. The nemertean vascular system is especially rich in arylamidases and is believed to be concerned primarily with peptidergic control of bodily functions, rather than with transport of metabolites.