Prey-capture techniques and prey preferences of Corythalia canosa and Pystira orbiculata, ant-eating jumping spiders (Araneae, Salticidae)

Corythalia canosa from Florida is an unusual salticid because it is known to eat ants. This species' specialized behaviour for catching ants is described in detail for the first time and compared to its behaviour for catching other insects. Pystira orbiculata from Queensland is shown to be another ant-eating salticid, although its behaviour for catching ants seems less specialized than that of C. canosa. Three different types of tests of prey preference were carried out. In each type of test C. canosa and P. orbiculata took ants in preference to other insects. Another species of salticid, Trite planiceps from New Zealand, failed to eat ants in these tests, although T. planiceps often attacked then released the ants. Corythalia canosa's and P. orbiculata's preference for ants, and their prey-specific predatory behaviour for catching ants, are shown not to depend on prior experience with ants.     

ANATOMICAL STUDIES REVEAL NEW PHYLOGENETIC INTERPRETATIONS IN LISSACHATINA (PULMONATA: ACHATINIDAE)

This is essentially a preliminary report on the revision ofsubgenus Lissachatina of the African land snail family Achatinidae.It extends the conchological revisionary work of J.C. Bequaert(1950) along the complementary line of comparative anatomicalstudies of the reproductive tracts. This is directed towardthe goal of a better understanding of phylo-geny in this family.Species emphasized are Achatina albopicta E.A. Smith,1878; A.allisa Reeve, 1849; A. fulica Bowdich, 1822; A. loveridgei Clench& Archer, 1930; A. zanzibarica Bourguignat, 1879, and thenew species A. eleanorae. Relegated tosynonymy are A. albicansPfeiffer, 1851; A. delorioli Bonnet, 1864; and A. iredalei Preston,1910. Tangible anatomical characters separate subgenera Lissachatinaand Achatina. A. capelloi Furtado, 1886; A. craveni E.A. Smith,1881; and A. connollyi Preston, 1912 are transferred from Lissachatinato Achatina s.s. Other transfers are in progress. (Received 26 September 1994; accepted 25 November 1994)     

Effect of nickel on oxygen free radical metabolism

The effect of nickel on superoxide dismutase activity (SOD), as well as on rate of hydroxydopamine oxidation, was studied in vitro since lipid peroxidation has been implicated in cell damage by nickel, whose toxicity and carcinogenicity are well established. Nickel strongly inhibits SOD activity. The degree of inhibition is directly proportion to the nickel concentration (tested range 0.066 to 0.33 microgram/mL in the reaction mixture); to the substrate concentration (tested range 0.4 x 10 4M to 1.1 x 10 4M 6-hydroxydopamine); and to reaction mixture. Autoxidation of 6-hydroxydopamine was increased by nickel concentrations higher than 15 micrograms/mL. The combination of excessive oxygen free radical production and inhibition of their elimination by inhibition of SOD activity may contribute to the nickel toxicity that has been reported in industrial accidents, as well as to the high incidence of cancer occurring in nickel workers. It may also contribute to many complications in uremic patients, in whom increased serum nickel levels were reported to be in a similar range to those inhibiting SOD.     

PARATI – a dynamic model for radiological assessments in urban areas

The structure and mathematical model of PARATI, a detailed computer programme developed for the assessment of the radiological consequences of an accidental contamination of urban areas, is described with respect to the scenarios used for the estimation of exposure fields in a village or town, the models for the initial and secondary contamination with the radionuclide ¹³⁷Cs, the concepts for calculating the resulting radiation exposures and the changes with time of the contamination and radiation fields. Kerma rates at various locations in tropical urban areas are given, and the contribution of different contaminated surfaces to these rates after dry or wet deposition are discussed. Received: 12 April 1996 / Accepted in revised form: 30 August 1996     

O-acetyl-salicylic acid promotes colony formation from protoplasts of an elite maize inbred

The salicylic acid derivative acetylsalicylic acid (ASA) was found to promote colony formation from protoplasts isolated from embryogenic suspension cultures of an elite maize inbred line. The drug was most effective at concentrations of 30–100 mg/l, and increases of more than 20-fold in the number of colonies recovered from protoplasts were obtained. The rate of growth of protoplast-derived cell colonies was not affected.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - DMSO dimethylsulfoxide - KM Kao and Michayluk medium (1975) - MES 2[N-morpholino]ethanesulfonic acid - ASA acetylsalicylic acid     

Interleukin inhibition by a parasite proteinase inhibitor, taeniaestatin

A proteinase inhibitor, taeniaestatin, isolated from the larval stage of the cestode Taenia taeniaeformis inhibits endogenous IL 2 generation in murine lymphocytes and IL 1 induced proliferation of murine thymocytes in a dose-dependent manner. However, taeniaestatin does not inhibit exogenous IL 2-induced proliferation of an IL 2-dependent cell line at any dose tested. These data indicate that the lack of IL 2 generation may be due in part to inhibition of a crucial cell-associated proteinase subsequent to cellular activation, or the lack of an effective IL 2 signal for differentiation. Our results are novel findings concerning molecular pathways for parasite inhibition of host immune responses, and suggest that selected proteinase inhibitors may be useful in clinical situations in which IL 1 or IL 2 are elevated.