Form changes in the sea bass, Dicentrarchus labrax (Moronidae: Teleostei), after acclimation to freshwater: an analysis using shape coordinates

Synopsis Morphological changes in the sea bass, Dicentrarchus labrax (Perciformes: Moronidae), were investigated after an experimental acclimation trial to freshwater. The sea bass is an euryhaline species occurring in the Mediterranean and west Atlantic from 30° N to 55° N. Part of the offspring of a pool of breeders was acclimated to freshwater at 9 months of age while maintaining the original stock in marine water. The effect of acclimation to freshwater over the entire form of the fish was studied through geometric morphometrics (shape coordinates). Changes in the form were shown graphically as landmark displacements though age classes 7,12, 15, 19 and 24 months and were discussed in the light of integrated growth. A significantly faster growth in freshwater was detected. Shape coordinates analyzed through multivariate statistics show that significant differences in shape arise after acclimation to freshwater. Moreover, the uniform component of shape change reveals a major effect of stretching or compression perpendicular to the body axis which is common and conservative in both trials. Differences are discussed in terms of selection and ecophenotypism.     

The results of 2-year pollen monitoring of an urban network in Perugia,Central Italy

Continuous pollen monitoring of an urban network consisting of three stations has been undertaken for a period of 2 years in Perugia, central Italy. The aim has been to establish whether the Perugia pollen trap, active since 1983, is still representative of the area following recent urbanisation. Quantitative differences were found between the stations, reflecting different vegetational areas, but only slight differences were detected in relation to the timing of the principal period of pollination. Therefore, although individual pollen traps are necessary to characterize fully the different areas, one trap is sufficient to determine the key allergenic thresholds in the studied area.     

The results of 2-year pollen monitoring of an urban network in Perugia,Central Italy

Continuous pollen monitoring of an urban network consisting of three stations has been undertaken for a period of 2 years in Perugia, central Italy. The aim has been to establish whether the Perugia pollen trap, active since 1983, is still representative of the area following recent urbanisation. Quantitative differences were found between the stations, reflecting different vegetational areas, but only slight differences were detected in relation to the timing of the principal period of pollination. Therefore, although individual pollen traps are necessary to characterize fully the different areas, one trap is sufficient to determine the key allergenic thresholds in the studied area.     

Purification and characterization of a truncatedBacillus subtilis α-amylase produced byEscherichia coli

ABacillus subtilis amylase gene was inserted into a plasmid which transferred toEscherichia coli. During cloning, a 3 region encoding 171 carboxyterminal amino acids was replaced by a nucleotide sequence that encoded 33 amino acid residues not present in the indigenous protein. The transformed cells produced substantial amylolytic activity. The active protein was purified to apparent homogeneity. Its molecular mass (48 kDa), as estimated in sodium dodecyl sulfate/polyacrylamide gel electrophoresis, was lower than the molecular mass values calculated from the derived amino acid sequences of theB. subtilis complete -amylase (57.7 kDa) and the truncated protein (54.1 kDa). This truncated enzyme form hydrolysed starch with aK _m of 3.845 mg/ml. Activity was optimal at pH 6.5 and 50°C, and the purified enzyme was stable at temperatures up to 50°C. While Hg²⁺, Fe³⁺ and Al³⁺ were effective in inhibiting the truncated enzyme Mn²⁺ and Co²⁺ considerably enhanced the activity.     

Unusual conformational preferences of β-alanine containing cyclic peptides. VII

In the present paper we describe the synthesis, purification, and single crystal x-ray analysis of the cyclic pentapeptide cyclo-(Pro-Phe-Phe-β-Ala-β-Ala). This compound crystallizes in the orthorhombic space group P2₁2₁2₁ from methanol and adopts in the solid state an unusual conformation characterized by a cis β-Ala⁵-Pro¹ peptide bond and by an intramolecular hydrogen bond stabilizing a C₁₁- and a C₁₂-ring structure. The C₁₁, structure contains the Phe³ and the β-Ala⁴ at the corner position of the turn; it is the first observation of a type II β-turn enlargement due to the insertion of an extra methylene group of the β-alanine residue. The rest of the molecule participates in a newly characterized C₁₂-ring structure, which incorporates a β-Ala residue at position i of the turn. © 1996 John Wiley & Sons, Inc.     

Developmental and pathogen-induced activation of an msr gene,str246C,from tobacco involves multiple regulatory elements

A family of genes, the so-called msr genes (multiple stimulus response), has recently been identified on the basis of sequence homology in various plant species. Members of this gene family are thought to be regulated by a number of environmental or developmental stimuli, although it is not known whether any one member responds more specifically to one stimulus, or whether each gene member responds to various environmental stimuli. In this report, we address this question by studying the tobacco msr gene str246C. Using transgenic tobacco plants containing 2.1 kb of 5′ flanking DNA sequence from the str246C gene fused to the β-glucuronidase (GUS) coding region, the complex expression pattern of the str246C promoter has been characterized. Expression of the str246C promoter is strongly and rapidly induced by bacterial, fungal and viral infection and this induction is systemic. Elicitor preparations from phytopathogenic bacteria and fungi activate the str246C promoter to high levels, as do wounding, the application of auxin, auxin and cytokinin, salicylic acid or copper sulfate, indicating the absence of gene specialization within the msr gene family, at least for str246C. In addition, GUS activity was visualized. histochemically in root meristematic tissues of tobacco seedlings and is restricted to roots and sepals of mature plants. Finally, analysis of a series of 5′ deletions of the str246C promoter-GUS gene fusion in transgenic tobacco plants confirms the involvement of multiple regulatory elements. A region of 83 by was found to be necessary for induction of promoter activity in response to Pseudomonas solanacearum, while auxin inducibility and root expression are apparently not controlled by this element, since its removal does not abolish either response. An element of the promoter with a negative effect on promoter activation by P. solanacearum was also identified.     

Maintenance of Weight Loss: A Needs Assessment

This study identified facilitators and obstacles to maintenance of weight loss following a very-low-calorie-diet and behavior modification program. A survey was mailed to a random sample of 178 program completers and received a 61% response rate; the most frequent follow-up period was more than 2 years. Twenty-nine percent reported weighing the same (within 10 lbs) or less than the end of their participation in the treatment program (maintainers), while 71% reported their present weight was a mean of 65% higher than their initial weight loss (regainers). Maintainers were significantly more likely to report engaging in regular aerobic exercise, attending a maintenance support group, and confidence in their ability to manage their weight in the future, while regainers were more likely to report stress and motivation as frequent weight management obstacles. Respondents consistently identified the need for low/no cost ongoing support. Maintainers and relapsers reported similar challenges in managing their weight, yet with different results, suggesting the need to identify subgroups for which different post-treatment support options could be applied.     

Ionization and binding equilibria of papaverine in ionic micelles studied by 1H NMR and optical absorption spectroscopy

The binding of the vasodilator drug papaverine (PAV) to micelles of zwitterionic N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS), cationic cetyltrimethylammonium chloride (CTAC) and anionic sodium dodecylsulfate (SDS) in aqueous solution was studied by 1H NMR and electronic absorption spectroscopy. In the presence of HPS or CTAC, the apparent pK(a) of PAV decreased by about 2 units, while it increased by about 2 units upon binding to SDS. However, the chemical shift patterns of both protonated (PAVH+) and deprotonated (PAV0) forms of PAV are not sensitive to the type of surfactant. The association constants were estimated as 5 +/- 2 M(-1) for PAVH+-CTAC, 8 +/- 3 M(-1) for PAVH+-HPS, (7 +/- 2) x 10(5) M(-1) for PAVH+-SDS, and 1.5 x 10(3) to 3.0 x 10(3) M(-1) for the complexes of PAV0 with all three types of micelles. Using these data, an electrostatic potential difference on the micelle-water interface was calculated as 150 +/- 10 mV for CTAC, 140 +/- 10 mV for HPS and - 140 +/- 10 mV for SDS. The results suggest that PAV aromatic rings are located in the hydrophobic part of the micelle. The electrostatic attraction or repulsion of the protonated quinoline nitrogen and surfactant headgroups changes the affinity of PAV to micelles and, thus, shifts the ionization equilibrium of PAV. The electrostatic potential of HPS micellar surface is determined by the cationic dimethylammonium headgroup fragment, whereas the anionic sulfate fragment attenuates the effective charge of HPS headgroup.     

Immunomicroscopical localization of human preformed natural antibodies against pig tissues in xenogeneic transplantation

Summary The targets of preformed natural antibodies need to be identified whenever the use of pig organs is considered for human transplantation. In this study we used extracorporeal perfusion of pig organs with human blood, immunocytological techniques and immuno-electron microscopy to identify the targets and the nature of human preformed natural antibodies against pig antigens. The antibodies were found to be mainly of the IgG and IgM type and directed not only against endothelial cells, but also against mesenchymal and epithelial structures. To reproduce an in vivo situation, a Bio-pump was used to xenoperfuse pig kidneys and livers with human fresh oxygenated blood at 37°C, drawn from polycythaemic patients. Biopsies showed a deposition of human IgG and IgM on tubuli and glomeruli of pig kidneys and on endothelial cells of pig livers. Preperfusion of pig liver with human blood for 45 minutes before perfusion of kidneys significantly reduced the deposition of the natural antibodies.