Evolutionary relationships among hares from North Africa (Lepus sp. or Lepus spp.), cape hares (L. capensis) from South Africa, and brown hares (L. europaeus), as inferred from mtDNA PCR-RFLP and allozyme data

Systematics and taxonomy of hares of the genus Lepus (Lagomorpha) are under contentious debate, and phylogenetic relationships among many taxa are not well understood. Here we study genetic differentiation and evolutionary relationships among North African hares, currently considered subspecies of Lepus capensis , cape hares ( L. capensis ) from the Cape province in South Africa, and brown hares ( L. europeaus ) from Europe and Anatolia, using maternally (mtDNA) and biparentally (allozymes) inherited markers. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of a c. 1.8 kb long segment of the mitochondrial control region using eight hexanucleotide-recognizing restriction endonucleases yielded 28 haplotypes, and horizontal starch gel electrophoresis of proteins encoded by 25 structural gene loci revealed 52 alleles at 18 polymorphic loci. Diverse phylogenetic analyses (neighbor joining dendrogram, median joining network, multidimensional scaling of pairwise distances, AMOVA, F -statistics, hierarchical F -statistics) of genetic variants revealed marked substructuring of mtDNA into three phylogeographic groups, namely an African, a central European, and an Anatolian, but a somewhat less pronounced overall differentiation of the nuclear genome, despite a relatively high number of population-specific (private) alleles. However, all our results are not incongruent with Petter's (1959: Mammalia 23 , 41; 1961: Z. f. Säugetierkunde 26 , 30; 1972 : Société Des Sciences Naturelles et Physiques du Maroc 52 , 122) hypothesis that North African hares generally belong to L. capensis and that brown hares should be included in this species as well.     

Rediscovery of Anthias salmopunctatus Lubbock & Edwards, 1981, with comments on its natural history and conservation

After c. 30 years without sighting or capture, Anthias salmopunctatus was rediscovered at the type locality, St Peter and St Paul's Rocks, Mid-Atlantic Ridge. To date, the known distribution is restricted to depths varying from 35 to 55 m in vertical drop offs around the perimeter of the islands ( c. 400 m). This may be the smallest geographic range known for a marine fish species.     

Vicariance patterns in the Mediterranean Sea: east–west cleavage and low dispersal in the endemic seagrass Posidonia oceanica

Aim The seagrass, Posidonia oceanica is a clonal angiosperm endemic to the Mediterranean Sea. Previous studies have suggested that clonal growth is far greater than sexual recruitment and thus leads to low clonal diversity within meadows. However, recently developed microsatellite markers indicate that there are many different genotypes, and therefore many distinct clones present. The low resolution of markers used in the past limited our ability to estimate clonality and assess the individual level. New high‐resolution dinucleotide microsatellites now allow genetically distinct individuals to be identified, enabling more reliable estimation of population genetic parameters across the Mediterranean Basin. We investigated the biogeography and dispersal of P. oceanica at various spatial scales in order to assess the influence of different evolutionary factors shaping the distribution of genetic diversity in this species. Location The Mediterranean. Methods We used seven hypervariable microsatellite markers, in addition to the five previously existing markers, to describe the spatial distribution of genetic variability in 34 meadows spread throughout the Mediterranean, on the basis of an average of 35.6 (± 6.3) ramets sampled. Results At the scale of the Mediterranean Sea as a whole, a strong east–west cleavage was detected (amova) . These results are in line with those obtained using previous markers. The new results showed the presence of a putative secondary contact zone at the Siculo‐Tunisian Strait, which exhibited high allelic richness and shared alleles absent from the eastern and western basins. F statistics (pairwise θ ranges between 0.09 and 0.71) revealed high genetic structure between meadows, both at a small scale (about 2 to 200 km) and at a medium scale within the eastern and western basins, independent of geographical distance. At the intrameadow scale, significant spatial autocorrelation in six out of 15 locations revealed that dispersal can be restricted to the scale of a few metres. Main conclusions A stochastic pattern of effective migration due to low population size, turnover and seed survival is the most likely explanation for this pattern of highly restricted gene flow, despite the importance of an a priori seed dispersal potential. The east–west cleavage probably represents the outline of vicariance caused by the last Pleistocene ice age and maintained to this day by low gene flow. These results emphasize the diversity of evolutionary processes shaping the genetic structure at different spatial scales.     

Effects of arsenate on the Ca2+ ATPase of sarcoplasmic reticulum

The effect of arsenate on the partial reactions of the catalytic cycle of the Ca2+ ATPase of skeletal muscle of sarcoplasmic reticulum was studied. With the use of native vesicles it was found that arsenate accelerates the rate of ITP hydrolysis and inhibits both Ca2+ or Sr2+ uptake. These effects were not observed when ATP was used as substrate or, with the use of ITP, when leaky vesicles were assayed. Activation of ITP hydrolysis is related to an increase of the enzyme's apparent affinity for ITP. Arsenate increases the steady-state level of the phosphoenzyme formed from ITP. This depends on the concentration of both Pi and Ca2+, in the medium. Ca2+ and Sr2+ efflux were accelerated by arsenate. The fast Ca2+ efflux promoted by arsenate is impaired by external Ca2+. Arsenate competes with Pi for the phosphorylating site of the enzyme.     

Copepods of the Juréia ecological reserve,state of São Paulo,Brazil. II. The genera Hesperocyclops,Muscocyclops, and Bryocyclops (Cyclopoida,Cyclopidae)

Cyclopid copepods collected mainly in aquatic microcosms and semiterrestrial habitats in the Juréia Ecological Reserve are studied. Hesperocyclops herbsti and Bryocyclops campaneri are described as new species and their taxonomical relationships discussed. Females of Muscocyclops operculatus (Chappuis) are redescribed and the males described for the first time. An emended diagnosis for Muscocyclops is proposed.     

Effects of α2-Adrenergic Agonists and Antagonists on Photoreceptor Membrane Currents

Type B photoreceptors of the nudibranch mollusc Hermissenda crassicornis receive excitatory synaptic potentials (EPSPs) whose frequency is controlled by potential changes of a neighboring cell known as the S optic ganglion cell which is thought to be electrically coupled to the presynaptic source of these EPSPs, the E optic ganglion cell. The frequency of the EPSPs increases when a conditioned stimulus (light) is paired with an unconditioned stimulus (rotation) during acquisition of a Pavlovian conditioned response. The results of the present study are consistent with an adrenergic origin for these EPSPs. Noradrenergic agonists (greater than 100 microM), norepinephrine and clonidine, only slightly depolarize the type B cell but clearly prolong its depolarizing response to light. Serotonin, by contrast, causes hyperpolarization of the type B cell's resting potential as well as after a light step. Clonidine reduces voltage-dependent outward K+ currents (IA, an early current, ICa2+-K+, a late Ca2+-dependent current) that control the type B cell's excitability (and thus its light response and membrane potential). These effects of clonidine are reduced or blocked by the alpha 2-receptor antagonist, yohimbine (0.5 microM), but not the alpha 1-blocker, prazosin. The same yohimbine concentration also blocked depolarizing synaptic excitation of the type B cell in response to depolarization of a simultaneously impaled S optic ganglion cell. Histochemical techniques (both the glyoxylic acid method of de la Torre and Surgeon and the formaldehyde-induced fluorescence or Falck-Hillarp method) demonstrated the presence of a biogenic amine(s) within a single neuron in each optic ganglion as well as three or four cells within the vicinity of previously identified visual interneurons. No serotonergic neurons were found within the optic ganglion or in proximity to visual interneurons. A clonidine-like synaptic effect on type B cells, therefore, could amplify conditioning-specific changes of membrane currents by increasing type B depolarization and possibly, as well, by elevating intracellular second messengers.     

Taste systems of the petrosal ganglion of the rat glossopharyngeal nerve

Single unit recordings were taken from sensory ganglion cellsin the petrosal ganglion (PG) of the glossopharyngeal nerveof the rat. These taste units were examined with respect tospontaneous and evoked discharge patterns and responsivenessto a wide variety of chemical compounds, most of natural occurrence.Spontaneous activity patterns, with few exceptions, tended tobe extremely irregular with both bursting (clusters of 2–3spikes) and grouping (large groups of spikes as in evoked discharges).Most interspike interval histograms of spontaneous activitywere multimodal, similar to rat geniculate ganglion (GG) units.Evoked discharges usually displayed grouping of spikes, andlong latencies of onset and persistence of discharge after rinsewere sometimes seen. Little response was shown to nucleotidesor salts. Units responsive to amino acids tended to show largedischarge to only one or two amino acids; and the most responsiveamino acid usually varied from cell to cell. Units responsiveto alkaloids only responded to a few alkaloids with atropineand quinine being the most stimulatory. Units responsive toacids only discharged to a few of the acids tested and oftenacids of low pH elicited no discharge. Saccharin activated unitsresponsive to both sugar and alkaloids. A few units highly responsiveto both sugar and alkaloids were seen. The units were placedinto four clusters on the basis of chemicals activating themand certain neurophysiological characteristics: PG salt units,PG acid units and, tentatively, amino acid (sugar) units andX (alkaloid and alkaloid plus) units. The PG salt units didnot show the exclusive sensitivity to sodium and lithium compoundsas did the GG salt units. The PG acid units could also be differentiatedfrom the GG acid units. The petrosal amino acid and X units,on the other hand, could not be differentiated from similarunits in the rat GG.