A new aspidorhynchid fish (Teleostei: Aspidorhynchiformes) from the Upper Jurassic of Ettling,Solnhofen, Bavaria,Germany

A new species of Aspidorhynchidae is described for the first time from the Late Jurassic of Ettling, some 50 km E-SE of Solnhofen, Bavaria, Germany. This new material is attributed to a new species, Aspidorhynchus sanzenbacheri, and is diagnosed by the abbreviated premaxillae, the form and disposition of teeth in the predentary, and the number of principal rays in the caudal fin.     

On the occurrence of the hydrocoral Millepora (Hydrozoa: Milleporidae) in the subtropical eastern Atlantic (Canary Islands): is the colonization related to climatic events?

The occurrence of a hydrocoral of the genus Millepora has been recorded for the first time in the eastern subtropical Atlantic (Tenerife, Canary Islands), at a latitude of 11o N of its previously known northernmost limit of distribution in the Cape Verde Islands. The moderate development of the colonies, their fast growth rate and very restricted location indicate a recent colonization process, possibly related to an extreme climatic event that took place in the summer of 2004, adding to the rising seawater temperatures in the region during recent years.     

Competitive interactions and partial displacement of Anastrepha obliqua by Ceratitis capitata in the occupation of host mangoes (Mangifera indica)

1. We examined the competitive interactions between a native fruit fly species (Anastrepha obliqua Macquart) and the invasive medfly (Ceratitis capitata Wiedemann) when these co-occur on a shared mango fruit host (Mangifera indica L.).
2. Using mango fruits of distinct levels of ripeness, we investigated both competition among larvae and among adult females for oviposition. We quantified competition by the numbers of eggs laid and the intensity of agonistic interactions between adult females.
3. Interactions between immature fruit flies led to reduced size and number of emerged adults of both species. These impacts were felt more acutely in the native species.
4. Interspecific competition between females led to fewer eggs laid on semi-ripe fruit by both species, which may be the result of niche overlap associated with oviposition.
5. Intraspecific interactions between A. obliqua individuals led to intense agonistic behaviour, with a concurrent decrease in number of landings on these host fruits.
6. These results suggest that the native species undergoes a partial niche displacement when facing the invasive species. A portion of the fundamental niche of A. obliqua remained unoccupied by the invading C. capitata, which may allow their coexistence under natural conditions.

     

Purification of adhesive proteins from mussels

The adhesive polyphenolic proteins from the mussels Mytilus chilensis and Choromytilus chorus have been purified based on their solubility in dilute perchloric acid and on differential precipitation with acetone containing about 0.3 N HCl. The specific activity of the proteins obtained was 0.16 mg of 3,4-dihydroxyphenylalanine per milligram of protein, or higher. The proteins have an apparent molecular weight of about 100,000 and they contain a high proportion of 3,4-dihydroxyphenylalanine, lysine, and proline.     

Modelling the acidifying activity profile of Lactobacillus bulgaricus cultures

A model that fully describes the typical pH(t) profile representing the lactic acid production kinetics of Lactobacillus bulgaricus cultures is reported. The model, a four-parameter function [pH = (A–D)/(1 + (t/C)^B) + D], is able to fit any change on the experimental pH-time curves, due to variations on the inoculum cell concentration of the culture. The four fitting parameters(A, B, C and D) of this model are closely related to the lactic acid fermentation and they have a physical meaning. Parameters A and D represent the initial and final pH of the culture, respectively. Parameter B is related to the slope of the linear decreasing region from the pH-time curve and C represents the time at which half of the total decrement of pH is achieved. The proposed model can be used not only for evaluating and comparing the acidifying capacity of homolactic cultures but also for predictions of final fermentation times.     

Functional analysis by site-directed mutagenesis of individual amino acid residues in the flavin domain of Neurospora crassa nitrate reductase

Nitrate reductase of Neurospora crassa is a complex multi-redox protein composed of two identical subunits, each of which contains three distinct domains, an amino-terminal domain that contains a molybdopterin cofactor, a central heme-containing domain, and a carboxy-terminal domain which binds a flavin and a pyridine nucleotide cofactor. The flavin domain of nitrate reductase appears to have structural and functional similarity to ferredoxin NADPH reductase (FNR). Using the crystal structure of FNR and amino acid identities in numerous nitrate reductases as guides, site-directed mutagenesis was used to replace specific amino acids suspected to be involved in the binding of the flavin or pyridine nucleotide cofactors and thus important for the catalytic function of the flavin domain. Each mutant flavin domain protein was expressed in Escherichia coli and analyzed for NADPH: ferricyanide reductase activity. The effect of each amino acid substitution upon the activity of the complete nitrate reductase reaction was also examined by transforming each manipulated gene into a nit-3 ^? null mutant of N. crassa. Our results identify amino acid residues which are critical for function of the flavin domain of nitrate reductase and appear to be important for the binding of the flavin or the pyridine nucleotide cofactors.     

Small nuclear ribonucleoprotein polypeptides in rat sperm.

1. Immunoblot analysis of rat sperm head proteins revealed the presence of polypeptides recognized by anti-Sm serum obtained from patients with systemic lupus erythematosus. 2. Two of these polypeptides have molecular weights of 26,000 and 15,000 and they were identified as small nuclear ribonucleoprotein components present in other rat tissues. 3. When the autoimmune serum was used in the immuno-gold procedure for electron microscopy, gold particles were found only on the sperm nucleus. 4. The results indicate that some polypeptides of the small nuclear ribonucleoprotein complex are components of the rat sperm chromatin.     

Synthesis and properties of complexes between lanthanide trifluoro-acetates and 2-picoline-n-oxide (2-picNO)

Complexes of lanthanide trifluoroacetates with 2-picoline-N-oxide (2-picNO), with composition Ln- (CF₃COO)₃·2(2-picNO), are described. They were characterized by elemental analysis, electrolytic conductance measurements, X-ray powder patterns, IR and absorption (neodymium) and emission (europium) spectra. The compounds were grouped in three isomorphous series: (a) La, Pf;(b), Nd, Sm and (c) Eu-Lu, Y. They behave as non-electrolytes in acetonitrile. Two types of coordination of the anion and coordination of 2-picNO through the oxygen are suggested. Absorption spectra indicate an essentially electrostatic interaction between Ln³⁺ and ligands. The fluorescence spectrum was interpreted in terms of a C_2v symmetry for the europium complex.