Organolanthanoids. XIII. Bis(pentadeuterocyclopentadienyl)ytterbium(II)

The complex (C₅D₅)₂Yb(dme) (dme = 1,2- dimethoxyethane) has been prepared by reaction of Tl(C₅D₅) with ytterbium metal in dme and is isostructural with (C₅H₅)₂Yb(dme). Thermal desolvation under vacuum yields (C₅D₅)₂Yb, for which essentially identical high resolution neutron powder diffraction data were obtained at 294 K and 77 K, but the structure could not be determined.     

AGRILUS CUPRIPES (CARTER) COMB. N. (COLEOPTERA: BUPRESTIDAE)

i
Synechocera cupripes Carter is transferred to Agrilus Stephens.
Subfamily BUPRESTINAE
Tribe AGRILINI
Genus Agrilus Stephens
Agrilus Stephens, 1830, Ill. Brit Ent. 3: 239.
Agrilus cupripes (Carter) comb.n.
Synechocera cupripes Carter, 1924, Proc. Linn. Soc. N.S.W. 49: 31.     

Lindernia kinmenensis sp. nov. (Scrophulariaceae) from Kinmen (Taiwan)

Lindernia kinmenensis Y. S. Liang, C. H. Chen, & C. L. Tasi sp. nov. from Kinmen (Taiwan) is described. The new species belongs to section Torenioides and is most similar to L. crustacea. It differs from the latter by the following characters: calyx pubescent between the ridges (vs pubescent on ridges), with (2)3(4) bristles on the ridge near the apex of the calyx‐lobes (vs without such bristles), corolla shorter, 6–8 mm long (vs 7–11 mm long) and pale purple (vs purple or blue), posterior theca with obtuse (vs acute) apex. This species is usually found in sandy wetlands. A line drawing, colour photos and SEM micrographs of pollen and seed as aids for identification are provided.     

Rhabditis (Rhabditis) freitasi sp.n. and Rhabditis (Rhabditis) costai sp.n. (Nematoda-Rhabditidae) isolated from bovine otitis

The author described two new species of Nematoda-Rhabditidae collected from the auditory meatus of catle with ear infection: Rhabditis (Rhabditis) freitasi sp.n. from Formosa county in the state of Goiás and Rhabditis (Rhabditis) costai sp.n. from Sert?ozinho county in the state of S?o Paulo.     

Rhabditis (Oscheius) pheropsophi n. sp. (Rhabditida: Rhabditidae)

Rhabditis (Oscheius) pheropsophi n. sp., associated with cadavers of the bombardier beetle, Pheropsophus aequinoctialis, is described from material collected in Brazil. Mean body length of the female is 1,217 μm, of the male 872 μm, and of the dauer juvenile 568 μm. The female has six lips with one papilla on each lateral lip and two on each sublateral lip; stoma wall thickened dorsally, metarhabdions with warts, excretory pore near base of esophagus, tail long (c = 8), and phasmids prominent, protruding on scanning electron microscope preparations. The male has 10 pairs of bursal ribs, with the terminal pair considerably smaller than the others; spicules fused distally two-thirds of their length. The new species can be distinguished from other members of the Dolichura-group by its fused spicules.     

Cricotopus (Cricotopus) nevadensis sp. n. (Diptera,Chironomidae) from Sierra Nevada (southern Spain)

Male and female imagines, and pupal exuviae of Cricotopus (C.) nevadensis sp. n. are described. A discussion on the systematic position, a differential diagnosis and notes on the ecology of this new species are given.     

Rhabdosciadium urusakii sp. nov. (Apiaceae) from east Anatolia (Turkey)

Rhabdosciadium urusakii E. Akal?n sp. nov. (Apiaceae) is described and illustrated. It occurs very locally on scree slopes in Kemaliye (Erzincan), east Anatolia. This slender species is closely related to R. aucheri (Iran) and R. oligocarpum (south Anatolia). It is a very rare and critically endangered species. A key to all Rhabdosciadium species is given in this paper. The new species is characterized by dichotomous branched, long petiolate, pinnate and linear leaves, ovate‐lanceolate bracts, a brownish band and hairs on the dorsal side of the petals.     

Block oligopeptides (L-lysyl)m-(L-alanyl) L-tyrosyl-(L-alanyl)n- (L-lysyl)m. I. Synthesis through fragment condensation and characterization

Model peptides containing one aromatic residue were synthesized and characterized in order to investigate their interactions with polynucleotides. Chromatographically pure block oligopeptides (L -alysyl)_m-(L -alanyl)_n- L -tyrosyl- (L -alanyl)_n, with n = 3 and m=3 or 6, were prepared by fragments condensation using the mixed anhydride method. The protected fragments were prepared by stepwise addition of amino acid residues through the dicyclohexylcarbodiimide method. The purity of the intermediate coupling product was analyzed by gradient elution chromotography on carboxylmethylcellulose. Both block oligopeptides were isolated by preparative chromatography on carboxymethylcellulose. The different features of these syntheses are discussed.     

Block oligopeptides (L-lysyl)m-(L-alanyl)n-L-Tyrosyl-(L-Alanyl)n-(L-Lysyl)m. II. Circular dichroism and pulsefluorimetry conformational studies

The conformation of chromatographically pure block oligopeptides (L -lysyl)_m-(L -alanyl)_n- L -tyrosyl-(L -alanyl)_n-(L -lysyl)_m with n = 3 and m = 6 or 3 is investigated. By circular dichroism it is shown that these peptides may exhibit a partially α-helical structure depending upon pH, ionic strength, solvent, and temprerature. An attempt is made to describe the helical content of these small peptides by utilizing the data obtained on high-molecular-weight poly(L -lysine). By measurement of the quantum yield and the decays of the peptides fluorescence, it is shown that, in aqueous solution, at neutral pH, the fluorescence of the peptides is quenched by interactions with the peptide carbonyl groups. The decays are multiexponential, which shows the presence of several conformations of the phenolic chromophore relative to the peptide chain. The addition of methanol, which induced the helix formation, decreases the quenching of the fluorescence and the multiexponential character of the decays. In presence of sodium hydroxide, which further increases the helical content of the peptides, a dynamic quenching occured that can be attributed to interactions between the phenol hydroxyl group of tyrosine (ith residue) and the ε-amino groups of the (i+4)th and (i -4)th lysyl residues.