Seabirds and marine mammals in the eastern Barents Sea: late summer at-sea distribution and calculated food intake

The at-sea distribution of seabirds and marine mammals in the eastern Barents Sea was determined using standardized transect counts during three cruises of RV“Dalnie Zelentsy” (Murmansk) in late summer 1991, 1992 and 1993. Totals of 32,268 seabirds, 485 pinnipeds, 25 cetaceans and 4 polar bears were counted during 554 half-hour counts. Numbers were converted into densities, total biomass and calculated daily food intake. Mean total food intake in kg fresh weight/km².day was 3.1 for the entire zone and all years; fish eaters dominated the whole region, with an intake of 1.3 (mainly Brünnich’s guillemot, Uria lomvia, and harp seal, Phoca groenlandica), followed by zooplankton eaters (0.85, mainly fulmar, Fulmarus glacialis) and mixed zooplankton and fish feeders (0.75, mainly minke whale, Balaenoptera acutorostrata, and kittiwake, Rissa tridactyla). Year-to-year variations were of little importance, while geographic differences were obvious between Norwegian coastal, Atlantic and Barents Sea water masses, both quantitatively and qualitatively (relative importance of main diets). Within each zone, a strong geographic heterogeneity was noted, with high local concentrations at fronts between water masses and at ice edges.     

A proenkephalin A-derived peptide analogous to bovine adrenal peptide E from frog brain: Purification, synthesis, and behavioral effects

A peptide derived from the posttranslational processing of proenkephalin A was isolated from an extract of the brain of the European green frog Rana ridibunda and its primary structure established as: Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-Gly-Arg¹⁰-Pro-Glu-Trp-Trp-Gln-Asp-Tyr-Gln-Lys-Arg²⁰-Tyr-Gly-Gly-Phe-Met. The structure was confirmed by chemical synthesis. The peptide represents an amphibian equivalent of bovine adrenal peptide E [preproenkephalin A (206–230)-peptide] but the sequence contains two amino acid substitutions (Met¹⁵ → Gln and Leu²⁵ → Met) compared with the mammalian peptide. The data support previous hypotheses that the Leu-enkephalin sequence is not present in preproenkephalin A of amphibians. Intracerebroventricular injections of frog peptide E (10 and 100 ng) in mice had no significant effect on horizontal locomotor activity. The peptide, in doses up to 1 μg, had no effect on latency of escape jumping in the hot plate test and the peptide (100 ng) did not modify responses (paw licking, rearing, and escape jumping) in morphine-treated mice.     

Purification and characterization of Kurloff cell sialoglycoproteins with acid phosphatase activity

The majora2–6 sialoglycoproteins in detergent-extracts of Kurloff cells were purified by anion-exchange andSambucus nigra agglutinin-affinity chromatographies. The similar ultrastructural localisations of (1)S. nigra agglutinin-gold conjugates and (2) acid phosphatase activities on the Kurloff body and particularly on its myelin figures indicated that the majora2-6 sialoglycoproteins of the Kurloff cell had acid phosphatase activity. Two-dimensional electrophoresis showed that these tartrate-sensitive phosphatases corresponded to 2 acidic (pI 3.4–3.7) polypeptides of 36 and 34 kDa. Hydrolysis with peptide-N-glycosidases F gave a 33 kDa apoprotein rich in alanine, glutamic acid, tyrosine and lysin. A lectin-affinity study demonstrated that they contained hybrid type bisected and fucosylatedN-linked oligosaccharides. Cytotoxic properties were previously attributed to Kurloff cells and other studies suggested that not only acid phosphatases but alsoa2-6-linked sialic acid residues themselves may participate in natural killer activity.     

Physical properties of methylcelluloses in relation with the conditions for cellulose modification

A high molecular weight glycoprotein antigen was isolated by size exclusion chromatography on Sepharose 4B from an extract of the yeast Saccharomyces cerevisiae. The glycoprotein antigen Sc 500 was shown to be identical to the antigen termed gp200 previously isolated (Heelan et al., 1991). The MW of Se 500 was determined to be about 500 kDa by size exclusion chromatography on Superose 6 and 460 kDa ± 20k Da by size-exclusion chromatography/multi-angle laser light scattering (SEC/MALLS). Sc 500 contained 90% mannose and traces of N-acetylglucosamine. The amino acid composition revealed that serine and threonine were the most abundant amino acids of the protein part. By alkaline borohydride treatment some, but not all bonds between protein and carbohydrate were broken. This indicates that the main type of linkage between protein and carbohydrate is O-glycosidic and that a minor type is of N-glycosidic nature. Methylation analysis revealed that the mannose residues were connected by 1 → 2 and 1 → 3 linkages with 1 → 2, 1→ 6 linked branch points.

Purified Sc 500 was subjected to a series of chemical and enzymatic modifications followed by studies of antibody binding activity. Treatments with both periodate and alkaline sodium borohydride reduced the human serum IgA, IgG and monoclonal IgM antibody binding activity of Sc 500 whereas trypsin and pronase did not affect its ability to bind these antibodies. The mannosidase Man1 → 2,3,6Man reduced the IgM binding to Sc 500 while the other enzymes included in this experiment (Man1→2 Man, Manβ1 →4GlcNAc and PNGase F) had no effect on the antibody binding.     

The Quaternary eolian sequence of Madeira: stratigraphy, chronology, and paleoenvironmental interpretation

A thick (ca. 40 m) sequence of coastal eolian sediments occurs on a narrow peninsula on the eastern end of the island of Madeira, located in the Eastern Atlantic at 33°N latitude. The sediments consist of black volcanic sands (with or without bioclasts) as well as clay units up to 2 m thick. A series of inceptisols (Eutrochrepts) and one alfisol (a Hapludalf) are developed in these sediments. Land snail shells and secondary carbonates, in the form of well-developed rhizoliths, calcretes, fissure-fills, and soil nodules, are present in abundance. The chronology of the sequence was determined by ¹⁴C and U---Th analyses of land snail shells and secondary carbonates and amino acid epimerization analysis of land snail shells. All sediments, including the clay units, are originally of eolian origin, derived from the beach to the south of the deposit, but some have been redeposited by colluviation. Temporal variation in the lithology of the sediments relates to variations in sea-level, with black sands being deposited during lower sea level stands and clays at the lowest. It is suggested that fine marine sediments, exposed during low sea-level stands, may also be the dominant source of silty or clayey units in other coastal eolian deposits in the subtropical Atlantic and Mediterranean.

The sequence spans from 200,000–300,000 years ago up to the 20th century. Sedimentation was discontinuous and often rapid; erosional hiatuses are present. During the Holocene, eolian sands started accumulating at 8200 yr B.P. during a transgressive phase and stopped at 4500 yr B.P. as sea level approached its present height. Colluviation increased dramatically following the first human settlement of the island in the 15th century and continued up to the 20th century, as dated by amino acid epimerization analysis of land snails. Earlier periods of colluviation were identified from the age distribution of land snail shells redeposited in younger colluvium.

Paleoenvironmental reconstruction was based mainly on soil and sediment features (including rhizolith morphology) and land snail faunas but also on stable isotope variations (¹³C, ¹⁸O) in land snails and secondary carbonates, pollen (generally not well preserved), and phytoliths. Most of the portion of the Middle Pleistocene represented in the sequence was characterized by moderately dry conditions, in comparison to the late Pleistocene and Holocene. During the last interglacial, relatively wet conditions occurred, wetter than during the Holocene interglacial. Moderately moist conditions were present during the accumulation of the thick unit dating to ca. 80,000 yr B.P. As sea level fell subsequent to this period, conditions appear to have become drier. Starting ca. 50,000–55,000 yr B.P., conditions were especially wet, but prior to the last glacial maximum, markedly arid conditions ensued. Toward the end of the last glacial, wet conditions returned and produced the best-developed soil preserved in the sequence. Moderately moist conditions occurred during the early to middle Holocene but apparently become slightly drier after 4500 yr B.P. The impact of human settlement can be seen in the loss of woody vegetation and enhanced gullying and colluviation during the last ca. 500 years.     

Inheritance and genetic mapping of resistance to Alternaria alternata f. sp. lycopersici in Lycopersicon pennellii

The fungal pathogen Alternaria alternata f. sp. lycopersici produces AAL-toxins that function as chemical determinants of the Alternaria stem canker disease in the tomato (Lycopersicon esculentum). In resistant cultivars, the disease is controlled by the Asc locus on chromosome 3. Our aim was to characterize novel sources of resistance to the fungus and of insensitivity to the host-selective AAL-toxins. To that end, the degree of sensitivity of wild tomato species to AAL-toxins was analyzed. Of all members of the genus Lycopersicon, only L. cheesmanii was revealed to be sensitive to AAL-toxins and susceptible to fungal infection. Besides moderately insensitive responses from some species, L. pennellii and L. peruvianum were shown to be highly insensitive to AAL-toxins as well as resistant to the pathogen. Genetic analyses showed that high insensitivity to AAL-toxins from L. pennellii is inherited in tomato as a single complete dominant locus. This is in contrast to the incomplete dominance of insensitivity to AAL-toxins of L. esculentum. Subsequent classical genetics, RFLP mapping and allelic testing indicated that high insensitivity to AAL-toxins from L. pennellii is conferred by a new allele of the Asc locus.     

Kurloff cell lysosomal arylsulphatases: Presence of both cationic and highly anionic isoforms of the sole B class

Following the previous ultrastructural demonstration of the presence of arylsulphatase (Asase) activities in Kurloff cells (KC) and of their quasi-exclusive localization in the Kurloff body (KB), this work investigates their biochemical and zymographic properties after extraction from purified KC suspensions. Using the discriminative inhibitory conditions of both the Baum or LeeVaupel and Conzelmann methods, nitrocatechol sulphate hydrolyzing enzymes of the KC were assumed to belong to the B class of the type II Asase alone. After electrophoretic separation under non-denaturing conditions in a 4–23% polyacrylamide gel, they were characterized by 55 kDa and 62 kDa zymographic bands. After isoelectric focusing, ‘classical’ cationic isoforms (pI 8.5) and two anionic isoforms (pI 4.4 and 4.6) were observed on zymograms. As expected for class B Asase, the different zymographic forms of KC Asase were only recovered in the unadsorbed fraction after anion-exchange chromatography on DEAE-cellulose column equilibrated with high ionic strength buffer. Their K_m (2.1 mM), their optimum pH (5.8) and their inhibitions by sulfite, phosphate, sulphate and ascorbic acid as well as their slight stimulation by AgNO₃ were also characteristic of this class of Asase. Finally, chondroitin4-sulphate was shown to potentially be a physiological substrate for these lysosomal enzymes.     

Homologous, homeologous, and illegitimate repair of double-strand breaks during transformation of a wild-type strain and a rad52 mutant strain of Saccharomyces cerevisiae.

Different modes of in vivo repair of double-strand breaks (DSBs) have been described for various organisms: the recombinational DSB repair (DSBR) mode, the single-strand annealing (SSA) mode, and end-to-end joining. To investigate these modes of DSB repair in Saccharomyces cerevisiae, we have examined the fate of in vitro linearized replicative plasmids during transformation with respect to several parameters. We found that (i) the efficiencies of both intramolecular and intermolecular linear plasmid DSB repair are homology dependent (according to the amount of DNA used during transformation [100 ng or less], recombination between similar but not identical [homeologous] P450s sequences sharing 73% identity is 2- to 18-fold lower than recombination between identical sequences); (ii) the RAD52 gene product is not essential for intramolecular recombination between homologous and homeologous direct repeats (as in the wild-type strain, recombination occurs with respect to the overall alignment of the parental sequences); (iii) in contrast, the RAD52 gene product is required for intermolecular interactions (the rare transformants which are obtained contain plasmids resulting from deletion-forming intramolecular events involving little or no sequence homology); (iv) similarly, sequencing data revealed examples of intramolecular joining within the few terminal nucleotides of the transforming DNA upon transformation with a linear plasmid with no repeat in the wild-type strain. The recombinant junctions of the rare illegitimate events obtained with S. cerevisiae are very similar to those observed in the repair of DSB in mammalian cells. Together, these and previous results suggest the existence of alternative modes for DSB repair during transformation which differ in their efficiencies and in the structure of their products. We discuss the implications of these results with respect to the existence of alternative pathways and the role of the RAD52 gene product.     

Times to exhaustion at 100% of velocity at [(V)\dot]\textO\text2 \dot V{\text{O}}_{\text{2}} max and modelling of the time-limit / velocity relationship in elite long-distance runners

The aim of this study was to measure running times to exhaustion (Tlim) on a treadmill at 100% of the minimum velocity which elicits _{max max} in 38 elite male long - distance runners _max = 71.4 ± 5.5 ml.kg^–1.min^–1 and _max = 21.8 ± 1.2 km.h^–1). The lactate threshold (LT) was defined as a starting point of accelerated lactate accumulation around 4 mM and was expressed in _max. Tlim value was negatively correlated with _max (r = -0.362, p< 0.05) and _max (r = –0.347, p< 0.05) but positively with LT (%v _max) (r = 0.378, p < 0.05). These data demonstrate that running time to exhaustion at _max in a homogeneous group of elite male long-distance runners was inversely related to _max and experimentally illustrates the model of Monod and Scherrer regarding the time limit-velocity relationship adapted from local exercise for running by Hughson et al. (1984) .     

CHROMOSOMAL VERSUS MITOCHONDRIAL DNA EVOLUTION: TRACKING THE EVOLUTIONARY HISTORY OF THE SOUTHWESTERN EUROPEAN POPULATIONS OF THE SOREX ARANEUS GROUP (MAMMALIA,INSECTIVORA)

The shrews of the Sorex araneus group have undergone a spectacular chromosome evolution. The karyotype of Sorex granarius is generally considered ancestral to those of Sorex coronatus and S. araneus. However, a sequence of 777 base pairs of the cytochrome b gene of the mitochondrial DNA (mtDNA) produces a quite different picture: S. granarius is closely related to the populations of S. araneus from the Pyrenees and from the northwestern Alps, whereas S. coronatus and S. araneus from Italy and the southern Alps represent two well-separated lineages. It is suggested that mtDNA and chromosomal evolution are in this case largely independant processes. Whereas mtDNA haplotypes are closely linked to the geographical history of the populations, chromosomal mutations were probably transmitted from one population to another. Available data suggest that the impressive chromosome polymorphism of this group is quite a recent phenomenon.