Fine-scale structure and cross-taxon congruence of bird and beetle assemblages in an old-growth boreal forest mosaic

Aim Nestedness occurs when species present in depauperate sites are subsets of those found in species‐rich sites. The degree of congruence of site nestedness among different assemblages can inform commonalities of mechanisms structuring the assemblages. Well‐nested assemblages may still contain idiosyncratic species and sites that notably depart from the typical assemblage pattern. Idiosyncrasy can arise from multiple processes, including interspecific interactions and habitat preferences, which entail different consequences for species co‐occurrences. We investigate the influence of fine‐scale habitat variation on nestedness and idiosyncrasy patterns of beetle and bird assemblages. We examine community‐level and pairwise species co‐occurrence patterns, and highlight the potential influence of interspecific interactions for assemblage structure. Location Côte‐Nord region of Québec, Canada. Methods We sampled occurrences of ground‐dwelling beetles, flying beetles and birds at sites within old‐growth boreal forest. We examined the nestedness and idiosyncrasy of sites and sought relationships to habitat attributes. We analysed non‐random species co‐occurrence patterns at pairwise and community levels, using null model analysis and five ‘association’ indices. Results All three assemblages were significantly nested. There was limited congruence only between birds and flying beetles whose nestedness was related to canopy openness. For ground‐dwelling beetles, nestedness was related to high stand heterogeneity and sapling density, whereas site idiosyncrasy was inversely related to structural heterogeneity. For birds, site idiosyncrasy increased with canopy cover, and most idiosyncratic species were closed‐canopy specialists. In all assemblages, species idiosyncrasy was positively correlated with the frequency of negative pairwise associations. Species co‐occurrence patterns were non‐random, and for flying beetles and birds positive species pairwise associations dominated. Community‐level co‐occurrence summaries may not, however, always reflect these patterns. Main conclusions Nestedness patterns of different assemblages may not correlate, even when sampled at common locations, because of different responses to local habitat attributes. We found idiosyncrasy patterns indicating opposing habitat preferences, consistent with antagonistic interactions among species within assemblages. Analysis of such patterns can thus suggest the mechanisms generating assemblage structures, with implications for biodiversity conservation.     

The maximal exercise ECG in asymptomatic men

Lead MC5 bipolar exercise ECG was obtained in 510 asymptomatic males, aged 40 to 65, utilizing the bicycle ergometer, with maximal stress in 71% of the subjects. “Ischemic changes” occurred in 61 subjects, the frequency increasing from 4% at age 40 to 45, to 20% at age 50 to 55, to 37% at age 61 to 65. Subjects having an ischemic type ECG change on exercise had more frequent minor resting ECG changes, more resting hypertension, and a greater incidence of high cholesterol values than subjects with a normal ECG response to exercise, but there was no difference in the incidence of obesity, low fitness, or high systolic blood pressure after exercise. Current evidence suggests that asymptomatic male subjects with an abnormal exercise ECG develop clinical coronary heart disease from 2.5 to over 30 times more frequently than those with a normal exercise ECG.     

Recognition of envelope and tat protein synthetic peptide analogs by HIV positive sera or plasma

A series of synthetic peptides corresponding to segments of HIV encoded proteins were selected using criteria described by Welling et al. [(1985) FEBS Lett. 188, 215]. Synthetic peptide analogs to gp120 (2-13), (55-65), gp41 (582-596) (659-670) and tatIII (71-83) were recognized by 41-67% of sera or plasma from individuals known to be infected with HIV on the basis of virus isolation or Western blot screening. The peptide which reacted with most sera or plasma was gp41 (582-596), a conserved region in the transmembrane glycoprotein. An extended peptide analog, gp41 (579-599), tested against the same samples showed almost 100% reactivity, confirming independent studies identifying a highly immunodominant region of gp41. There was an unexpected high prevalence of antibodies (25%) to the tatIII peptide.     

Agonistic behaviour,responses to a novel object and some aspects of maintenance behaviour in feral-strain and domestic chickens

Feral-strain fowl, bred from birds captured on North-West Island (24°S, 150°E), were compared with domestic chickens hatched and raised under similar conditions. Aspects of behaviour considered included agonistic behaviour and responses to unfamiliar environments and objects. There were many similarities between the feral and domestic fowl in behaviour, but there were also many differences between the strains.Feral cockerels showed higher levels of agonistic behaviour than domestic cockerels, under some conditions. There were differences between young feral and Leghorn-cross chickens in the “freezing” response to handling and placement in an unfamiliar cage, with the feral chickens responding more rapidly.Feral cockerels showed a greater initial avoidance of a novel object than did Black Australorp bantam cockerels, but after a short interval they spent more time near the novel object than the bantams.These results are discussed in relation to selection pressures under conditions of domestication, and on North-West Island.     

Hydrazinolysis-N-reacetylation of glycopeptides and glycoproteins. Model studies using 2-acetamido-1-N-(L-aspart-4-oyl)-2-deoxy-beta-D-glucopyranosy lamine

2-Acetamido-1-N-(L-aspart-4-oyl)-2-deoxy-beta-D-glucopyranosyla mine (1) was used as a model glycopeptide to study the hydrazinolysis-N-reacetylation procedure. The major, initial product was the beta-acetohydrazide derivative of 2-acetamido-2-deoxy-D-glucose (2) which gave 2-acetamido-2-deoxy-D-glucose (5) after exposure to acidic conditions. Very mild conditions of hydrolysis of 2 gave a 75-80% overall yield of 5 from 1 after the hydrazinolysis-N-reacetylation procedure. Several other minor compounds were detected which were not converted into 5 upon mild acid hydrolysis, indicating that 20-25% of product cannot be recovered as 5 at the reducing end of oligosaccharides.     

A set of surface proteins common to the circulating human platelet and lymphocyte (Short Communication)

The surface proteins of the circulating human platelet and lymphocyte were labelled by using the lactoperoxidase iodination method. Polyacrylamide-gel electrophoresis showed that four corresponding labelled proteins are found on the surface of each cell type. The most intensely labelled protein contains little or no carbohydrate, but the remaining labelled proteins are all glycoproteins. The major labelled band from each cell was isolated and comparative peptide ;maps' showed that the two proteins are closely similar. The surface proteins of the lymphocyte and platelet are distinct from those on the erythrocyte, the remaining major type of circulating cell.     

Protein kinase activities in rat liver nuclei: Effects of age and partial hepatectomy

Selective substrates and inhibitors have been used to measure kinases phosphorylating endogenous proteins in rat liver nuclei during growth and regeneration after partial hepatectomy. Peaks in activity were found at 5, 22, and 29 hours after partial hepatectomy. Administration of ₁ and adrenergic blockers suggested that the Be²⁺ sensitive and cyclic AMP-dependent protein kinases were interdependently regulated by Ca²⁺ and cyclic AMP.