Particle capture by Favella sp. (Ciliata, Tintinnina)

Particle capture by the tintinnid ciliate, Favella sp., wasinvestigated with high-speed video microscopy. Experiments withmicrospheres and algal cells indicate that within the size range1–19 p.m. behavioral responses are partly responsiblefor the differential capture of large over small particles.For example, 4 µm microspheres or Isochrysis [spheiicaldiameter (ESD) - 4.5 µ are only captured if they are encounteredin the inner zones of the encounter area. Ten micrometer microspheresor Heterocapsa(14–19 – are captured with a greaterefficiency than smaller particles from the inner zones, butcan also be captured from the outer zone of the encounter area.Capture of particles from the outer zone is associated withcilialy reversal. Microsp1ieres and algal cells of similar sizeare captured in a similar manner.     

Digestion time and intactness of seeds ingested by Sturnira lilium (E. Geoffroy, 1810) (Mammalia,Chiroptera)

Bats are responsible for many ecological services, such as seed dispersal of several plant species, contributing to the processes of succession and forest regeneration. A factor that can interfere with this process is the animal digestion, which can affect germination, altering the patterns of seedling distribution. The effects of seed passage through bats’ guts varies with the species, leading to some discrepancies in the literature. In this study, we tested the digestion time of one Phyllostomidae bat species, Sturnira lilium, in two Neotropical plants: Solanum paniculatum and Ficus organensis, and the effects on seed germination. The experiment was conducted in captivity and the germination tests were made in laboratory conditions. The results suggested that most seeds ingested by S. lilium are dispersed within 40 min for both species and the digestion seems not to significantly affect the germination of F. organensis, despite the slight acceleration of germination. In S. paniculatum, germination occurred only in the control (39%), whereas in the treatments, all the seeds remained dormant during the 25 experimental days. In this case, the digestion of S. lilium possibly contributes to the formation of seed banks, randomizing the temporal distribution of seedlings.     

New Paramecium quadecaurelia strains (P. aurelia spp. complex,Ciliophora) identified by molecular markers (rDNA and mtDNA)

Paramecium quadecaurelia is a rare species (previously known only from two locations) belonging to the P. aurelia species complex. In the present paper, fragments of an rDNA gene (ITS1-5.8S-ITS2-5′ rDNA) and mtDNA genes (cytochrome oxidase subunit I and cytochrome b regions) were employed to assist in the identification and characterization of three new strains collected from Ecuador and Thailand. Molecular data were confirmed by mating reactions. In rDNA and mtDNA trees constructed for species of the P. aurelia complex, all P. quadecaurelia strains, including the three new strains discussed in this study and two known previously from Australia and Africa, form a monophyletic but differentiated clade. The present study shows that genetic differentiation among the strains of P. quadecaurelia is equal to or even greater than the distances between some other P. aurelia species, e.g., P. primaurelia and P. pentaurelia. Such great intra-specific differentiation may indicate a future splitting of the P. quadecaurelia species into reproductively isolated lines.     

Metabolic and cellular alterations induced by diesel oil in Hypnea musciformis (Wulfen) J. V. Lamour. (Gigartinales,Rhodophyta)

Understanding the mechanisms by which marine organisms cope to environmental stressful conditions is a fundamental question for ecotoxicology. We examined biochemical and cellular responses of Hypnea musciformis exposed in vitro to four concentrations of diesel oil (0 (control), 0.001, 0.01, 0.1, and 1 % v/v) for 0, 30 min, 1, 12, and 24 h. Chl a content decreased after exposure for 1, 12, and 24 h. Carotenoids increased after 30 min and 12 h and decreased after 1 and 24 h. Phenolic content was lower in samples exposed to 0.1 and 1 % of diesel oil. After treatment, samples showed a decrease in floridean starch grains, cell volume and autofluorescence intensity, changes in chloroplast morphology, and on the surface topography of the cell wall. These findings provide preliminary but important results on biochemical and cellular responses of H. musciformis when exposed to diesel oil and could be considered as tools for monitoring oil spills.     

Ejaculations induced by p-chloroamphetamine (PCA) in rats, hamsters and mice.

The ejaculatory response induced by p-chloroamphetamine (PCA) in male rats, hamsters and mice was observed during 2 hours after the injection. The animals were treated intraperitoneally with PCA at doses ranging from 0.78125 to 160 mg/kg. The ED50 (effective dose in 50% of animals) values of PCA for the initiation of ejaculation in rats and hamsters were 1.3397 (1.0732-1.6725) and 0.1105 (0.0802-0.1522) mg/kg, respectively. On the other hand, no ejaculation was observed in any mice at any doses examined. So we concluded that there are species differences in the ejaculatory response, induced by PCA, among rats, hamsters and mice.     

Arenopontia (Neoleptastacus) huysi, sp. nov. (Crustacea, Copepoda, Harpacticoida) from marine interstitial of Montenegro (S.E. Europe)

A new species of Arenopontia (Neoleptastacus) is described on the basis of a single female collected from one sandy beach in Montenegro, Adriatic Sea. With the addition of the new species, the subgenus Neoleptastacus now includes 18 species throughout the world. At the end of this paper there is a key for their determination. Received: 20 March 1999 / Received in revised form: 15 September 1999 / Accepted: 21 September 1999     

Pollination by flies, bees, and beetles of Nuphar ozarkana and N. advena (Nymphaeaceae)

Nuphar comprises 13 species of aquatic perennials distributed in the temperate Northern Hemisphere. The European species N. lutea and N. pumila in Norway, the Netherlands, and Germany are pollinated by bees and flies, including apparent Nuphar specialists. This contrasts with reports of predominant beetle pollination in American N. advena and N. polysepala. We studied pollination in N. ozarkana in Missouri and N. advena in Texas to assess whether (1) there is evidence of pollinator shifts associated with floral-morphological differences between Old World and New World species as hypothesized by Padgett, Les, and Crow (American Journal of Botany 86: 1316-1324. 1999) and (2) whether beetle pollination characterizes American species of Nuphar. Ninety-seven and 67% of flower visits in the two species were by sweat bees, especially Lasioglossum (Evylaeus) nelumbonis. Syrphid fly species visiting both species were Paragus sp., Chalcosyrphus metallicus, and Toxomerus geminatus. The long-horned leaf beetle Donacia piscatrix was common on leaves and stems of N. ozarkana but rarely visited flowers. Fifteen percent of visits to N. advena flowers were by D. piscatrix and D. texana. The beetles' role as pollinators was investigated experimentally by placing floating mesh cages that excluded flies and bees over N. advena buds about to open and adding beetles. Beetles visited 40% of the flowers in cages, and flowers that received visits had 69% seed set, likely due to beetle-mediated geitonogamy of 1st-d flowers. Experimentally outcrossed 1st-d flowers had 62% seed set, and open-pollinated flowers 76%; 2nd-d selfed or outcrossed flowers had low seed sets (9 and 12%, respectively). Flowers are strongly protogynous and do not self spontaneously. Flowers shielded from pollinators set no seeds. A comparison of pollinator spectra in the two Old World and three New World Nuphar species studied so far suggests that the relative contribution of flies, bees, and beetles to pollen transfer in any one population depends more on these insects' relative abundances (and in the case of Donacia, presence) and alternative food sources than on stamen length differences between Old World and New World pond-lilies.     

Differential stabilization by netropsin of inducible B-like conformations in deoxyribo-, ribo- and 2'-deoxy-2'-fluororibo-adenosine containing duplexes of (dA)n . (dT)n and (dA)n . (dU)na.

Six polynucleotide duplexes containing polydeoxyadenylic acid, polyadenylic acid or poly-2'-deoxy-2'-fluoro-adenylic acid in one strand, and polydeoxyuridylic acid or polydeoxythymidylic acid in the other strand have been studied by circular dichroism, ionic strength dependence of melting temperatures and binding of the DNA specific antibiotic netropsin. Circular dichroism spectra of (dA)n . (dT)n and (dA)n . (dU)n indicated the presence of the B-form of DNA, while those of (dAfl)n . (dT)n and (rA)n . (dT)n (and the corresponding (dU)n hybrids) indicated the presence of the A-form. (dAfl)n . (dT)n and (dAfl)n . (dU)n bound netropsin only slightly less than the (dA)n containing duplexes, while replacement by (rA)n decreased netropsin binding to a large degree. Since netropsin requires B-DNA for binding, it is concluded that the A to B transition is facilitated in the case of fluorine substitution in the sugar moiety, while the 2'-OH group greatly limits this conformational change.     

Pseudangularia gonzalezi n. sp. and Gibsonilepis swifti (Singh, 1952) n. g., n. comb. (Cestoda, Dilepididae) from the House Swift, Apus affinis (J.E. Gray) (Aves, Apodiformes) from Franceville, Republic of Gabon

Nine specimens of Apus affinis (J.E. Gray) were studied at Franceville, Haut-Ogooué Province, Republic of Gabon, for the presence of helminth parasites. Two cestode species of the family Dilepididae were recorded. Pseudangularia gonzalezi n. sp. is distinguished from the most similar species P. europaea Georgiev & Murai, 1993 by having elliptical cirrus-sac, longer vagina, longer rostellar sheath and greater diameter of suckers. An identification key to the species of the genus Pseudangularia Burt, 1938 is proposed. The present study is the first record of the genus Pseudangularia in the Afrotropical Region. Our study confirms that, in dilepidids with vaginal sclerites from swifts, breaking off the cirrus after copulation is a frequent phenomenon. The genus Gibsonilepis n. g. is erected as monotypic for Vitta swifti Singh, 1952 (originally described from the same host species in India) and Gibsonilepis swifti n. comb. is proposed. Gibsonilepis n. g. is distinguished from Vitta Burt, 1938 by its highly elongate rostellum, rostellar sheath much bigger than rostellum, relatively small rostellar hooks possessing strongly developed guard, disc-shaped suckers with weak peripheral musculature and flat or convex central part, long and well-expressed neck, highly lobed two-winged ovary (lobes rounded) and presence of a band consisting of rows of spine-like microtriches along posterior margin of each proglottis. This is the first record of G. swifti in the Afrotropical Region. The separation of G. swifti from the genus Vitta (parasites of swallows) suggests that, contrary to previous opinions, no dilepidid genera are shared by Apodidae (swifts) and Hirundinidae (swallows).