Structure and function of hemoglobin in antarctic fishes and evolutionary implications

Summary The hematological features of cold-adapted, red-blooded Antarctic teleosts has prompted this study on the relationship between hemoglobin molecular structure and oxygen-binding properties. The hemolysates from 21 species of 5 families contained one component (Hb 1), often accompanied by an additional, minor one (Hb 2, 5%–10% of total). On the other hand, 3 species of Zoarcidae, a non-endemic family, had 4–5 components. All purified hemoglobins from the former group, but only 1–2 of the 4–5 hemoglobins of Zoarcidae, showed a strong Root effect (pH regulation of oxygen binding). Globins from each hemoglobin have been purified and characterised with respect to molecular structure in several species. The similarity between the complete amino acid sequence of one -chain and those of non-Antarctic -chains is lower than that among the latter sequences, suggesting independent pathways of evolution.Presented at the 5th SCAR Symposium on Antarctic Biology, Hobart, Australia (August 29th-September 3rd, 1988)     

β-thalassemia mutations in the Portuguese population

Summary In this study we have carried out haplotype analysis on the -globin gene cluster and characterized the -thalassemia mutation by oligonucleotide hybridization in 14 patients with thalassemia major and 5 with sickle cell/-thalassemia originating from southern Portugal. We found that three mutations, namely the °-39, ° IVS-1 nt 1 and ⁺ IVS-1 nt 110 are prevalent accounting for 53%, 32% and 10% of the -thalassemia chromosomes respectively. In general each mutation was associated with a specific chromosomal haplotype; the ° mutation, however, was linked to three different haplotypes. These results indicate that three oligo-probes complementary to the most common mutations allow prenatal diagnosis by oligonucleotide analysis in 96% of the couples at risk of having offspring with thalassemia major in southern Portugal.     

Modified inoculum for radiometric susceptibility testing ofMycobacterium tuberculosis

Two-hundred and fifteen isolates ofMycobacterium tuberculosis were evaluated with the BACTEC 460 radiometric method for susceptibility to isoniazid, rifampin, ethambutol, and streptomycin (SM); a revised protocol for inoculum preparation was used. Fresh clinical isolates were subcultured into 7H9 broth and then photometrically adjusted to the equivalent of a 0.5 McFarland standard, one-half the recommended inoculum density. This method produced an overall 98.3% correlation with a conventional agar method. The sensitivity of this procedure was good for all drugs tested except for the lowest concentration of SM (2 g/ml). Specificity was excellent for all drugs tested. After repeat testing, only four discrepancies were found, yielding a 99.8% correlation between the two systems. The time required for susceptibility tests averaged 4.6 days. This method for inoculum preparation effectively minimized the number of susceptibility tests exceeding the threshold value before the fourth day of incubation. This allowed for definite trends of the growth index values to become established before interpretation of results.     

Lethal activity of miconazole in Neisseria gonorrhoeae grown in pure and mixed cultures

Abstract Low concentrations (e.g. 2 × 10⁻⁶ M) of an imidazole derivative anti-fungal agent, miconazole, were lethal for the Gram-negative, facultative aerobic pathogen Neisseria gonorrhoeae grown either alone or in mixed culture with the yeast Candida albicans . Electron microscopic observation of Neisseria cells exposed to miconazole showed the presence of blebs in the outer wall and areas of separation between the wall and the cytoplasmic membrane. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cell lysates did not reveal differences in major outer membrane proteins between the treated and the untreated cells of any one strain. Imidazole derivatives are frequently used in the treatment of candidiasis. Our in vitro results show that low concentrations of one of them, miconazole, can be bactericidal for N. gonorrhoeae , a bacterium that can colonise sites of the human body where Candida is often found.     

Production and purification of Escherichia coli fimbrial antigen F165

Abstract The production of fimbrial antigen F165 by Escherichia coli strains was found to be dependent on the composition of the culture medium and was repressed in the presence of alanine or high levels of glucose, in anaerobic conditions or at growth temperatures of lower than 37°C. Optimal F165 production was found on a minimal medium containing 1% (w/v) casamino acids (MD-1). F165 antigen was isolated from bacteria by mechanical shearing, precipitated with ammonium sulfate, and purified by deoxycholate treatment and gel filtration on Superose 12. The purified fimbriae retained their native morphology as observed by electron microscopy and consisted of two separate protein subunits with apparent molecular weights of 17 500 and 19 000 on sodium dodecyl sulfate-polyacrylamide gels.     

Hormone-induced vocal behavior and midbrain auditory sensitivity in the green treefrog,Hyla cinerea

Summary Twenty four castrated male, 6 intact male, and 11 intact female Hyla cinerea were injected subcutaneously with 25 g arginine-vasotocin (AVT) and induced to call 1 h later in response to the playback of a conspecific mating call. Eighteen castrated males and 8 intact females were implanted 5 mg androgen pellets for 3 weeks prior to the neuropeptide injection. Among castrated males, 6/9 testosterone (T) implanted, 4/9 dihydrotestosterone (DHT) implanted and 2/6 non implanted individuals produced calls after being administered AVT. 5/6 intact non implanted males and 6/8 T intact implanted females also called, and 3 intact non implanted females remained silent after the injection. Evoked calls had a mid-frequency spectral peak at about 1900 Hz which is absent in field-recorded mating calls of this species. Calls of implanted females and castrated non implanted males were shorter than those of castrated implanted and intact non implanted males. Audiograms measured before hormone implants showed dips of enhanced sensitivity at about 0.5, 0.9 and 3.0 kHz in males and females. After AVT injection, thresholds at frequencies within the 0.7–1.5 kHz range were increased in castrated males. Such reduction in sensitivity points to an inhibition of the auditory system during hormone induced vocal activation.Abbreviations AVT arginine-vasotocin - DHT dihydrotestosterone - T testosterone - TS torus semicircularis     

Exposure to p-phenylendiamine in hairdressing parlours

Summary The purpose of this study is to verify and assess, in working conditions, the respiratory exposure to PPD of hairdressing parlour personnel. Several air samples collected in a hairdressing parlour during the time required for 8 applications of dyeing products containing PPD 2.52% have been analyzed. Tests are also carried out by extracting air immediately above the bowls containing the dyeing products, both at room temperature and at 37°C. PPD was assessed by means of HPLC. Only air sampled directly on bowls at 37°C has shown a level of 1 g, corresponding to an environmental release of PPD equivalent to 8 applications of dyeing products. On the basis of these experimental data, the PPD concentration in the air according to the parlour volume and to the supposed air exchanges has been calculated. Our results show a substantial insignificance of the concentration of PPD released in the environmental air during normal operations of hair dyeing: authors are of the opinion that hairdressers can't be truly considered as a PPD-asthmatic risk category like other workers exposed to PPD dust dispersed in the air of their working environment.     

Pollinosis in trentino (Northern Italy). Aerobiological and clinical research

Summary A study to evaluate and define the atmospheric pollen concentration in Trentino was carried out through the aerobiologic sampling in three localities chosen according to their different climatic conditions.1375 patients with pollinosis living in Trentino were studied retrospectively over the period ranging from 1986 to 1988 and selected according to the area they came from.Results have proved that the most allergenic pollen types are the following: Poaceae, Urticaceae (Parietaria), Compositae (Artemisia) and the tree pollen of Betulaceae and Corylaceae (Alnus, Betula, Corylus), and that pollinosis caused by such pollen, types has different features and frequencies according to the different localities.As far as symptoms are concerned, our data shows that rhinoconjuntivitis is more frequent in those patients who are allergic toParietaria while asthma results being more frequent in patients who are allergic to tree pollen.     

A detailed study of the regulation and evolution of the two classes of patatin genes in Solanum tuberosum L.

The class-specific expression of patatin genes was investigated by analysing four new patatin genes. A class I patatin gene from cv. Berolina as well as a class I and two class II patatin genes from the monohaploid cultivar AM 80/5793 were isolated and partially sequenced. Sequence comparison indicates rearrangements as the major source for the generation of diversity between the different members of the classes. The expression of single genes was studied in potato plants transformed with chimaeric genes where the putative patatin promoters were fused to the GUS reporter gene. A detailed histochemical analysis reveals that both class I genes are expressed as the previously described class I patatin gene B33 from cv. Berolina [1], i.e. in the starch-containing cells of potato tubers and in sucrose-induced leaves. The class II gene pgT12 shows the same pattern as the previously described class II gene pgT2 [2], i.e. expression in root tips and in the vascular tissue of tubers, whereas no activity was detectable for pgT4. Thus the expression pattern of both classes of genes seems to be stable at least within or even between different cultivars.