Nest predation in hole-nesting birds in relation to habitat edge: an experiment

We experimentally tested the hypothesis that nest predation rate in hole-nesting birds, especially the common goldeneye Bucephala clangula , was related to the edge between aquatic and terrestrial habitats We also studied whether nest predation rate was related to habitat patch (lake) size In three study areas nest-boxes were erected in pairs one nest-box was erected at the shoreline and the other one inside the forest at a varying distance (range from 14 to 140 m) from the shoreline One chicken egg was placed in each nest-box (dummy nest) Overall predation rate on dummy nests varied from 34 6% to 52 6% depending on the study area The pine marten Martes manes was the primary nest predator m all study areas Daily predation rates did not differ between natural and dummy nests Predation rate on dummy nests was not related to the distance of the nest-box from the shoreline in any study area Predation rate was not related to lake size in two study areas but in one area predation rate on dummy nests was lower around largest lakes However, the result may be accidental and not because of lake size per se because the proportion of forest was exceptionally low in that part of the study area     

Histamine immunohistochemistry: a new and highly sensitive method for studying cutaneous mast cells

Summary Mast cells have characteristic granulae containing various glucoseaminoglycans, proteases and amines (predominantly histamine). The conventional histological methods for studying mast cells are based upon acidic ortho-and metachromatic routine stains of the glucoseaminoglycans. However, the success of these procedures is dependent upon both the fixatives and the tissues used. In this study, we wanted to find out whether an immunohistochemical procedure could overcome some of these difficulties. Normal human skin was fixed in five different types of fixative and processed for indirect immunofluorescence, using an antiserum to histamine. Only one, 4% carbodiimide in 0.1m phosphate buffer (pH 7.4), resulted in immunostaining. The quality of the staining was good, with a high signal-to-noise ratio, and was located on the mast cells. The method, made it possible to visualize small structures such as a single secreted granula, the thin cytoplasmatic extension of some cells, and a previously undescribed dendritic morphology of some of the mast cells. We therefore recommend, this procedure for cellular studies of mast cells when accuracy is needed.     

Location and Distribution of Non-collagenous Matrix Proteins in Musculoskeletal Tissues of Rat

The study assessed immunohistochemically the location and distribution of various non-collagenous matrix proteins (fibronectin, laminin, tenascin-C, osteocalcin, thrombospondin-1, vitronectin and undulin) in musculoskeletal tissues of rat. Fibronectin and thrombospondin-1 were found to be ubiquitous in the studied tissues. High immunoreactivity of these proteins was found in the extracellular matrix of the anatomical sites where firm bindings are needed, i.e. between muscle fibres and fibre bundles, between the collagen fibres of a tendon and at myotendinous junctions, osteotendinous junctions and articular cartilage. Tenascin-C was found in the extracellular matrix of regions where especially high forces are transmitted from one tissue component to the other, such as myotendinous junctions and osteotendinous junctions. Laminin was demonstrated in the basement membranes of the muscle cells and capillaries of the muscle–tendon units. Osteocalc in immunoreactivity concentrated in the extracellular matrix of areas of newly formed bone tissue, i.e. in the subperiosteal and subchondral regions, osteoid tissue and mineralized fibrocartilage zone of the osteotendinous junction. Mild vitronectin activity could be seen in the extracellular matrix of the osteotendinous and myotendinous junctions, and high activity around the bone marrow cells. Undulin could be demonstrated in the extracellular matrix (i.e. on the collagen fibres) of the tendon and epimysium only. However, it was co-distributed with fibronectin and tenascin-C. Together, these findings on the normal location and distribution of these non-collagenous proteins in the musculoskeletal tissues help to form the basis of knowledge against which the location and distribution of the these proteins in various pathological processes could be compared.     

Enzymatic Properties and Intracellular Localization of the Novel Trichoderma reesei β-Glucosidase BGLII (Cel1A)

This paper describes the characterization of an intracellular β-glucosidase enzyme BGLII (Cel1a) and its gene (bgl2) from the cellulolytic fungus Trichoderma reesei (Hypocrea jecorina). The expression pattern of bgl2 is similar to that of other cellulase genes known from this fungus, and the gene would appear to be under the control of carbon catabolite repression mediated by the cre1 gene. The BGLII protein was produced in Escherichia coli, and its enzymatic properties were analyzed. It was shown to be a specific β-glucosidase, having no β-galactosidase side activity. It hydrolyzed both cellotriose and cellotetraose. BGLII exhibited transglycosylation activity, producing mainly cellotriose from cellobiose and sophorose and cellobiose from glucose. Antibodies raised against BGLII showed the presence of the enzyme in T. reesei cell lysates but not in the culture supernatant. Activity measurements and Western blot analysis of T. reesei strains expressing bgl2 from a constitutive promoter further confirmed the intracellular localization of this β-glucosidase.     

Social influences on food caching in willow tits: a field experiment

We studied the food hoarding behavior of willow tits (Parusmontanus), a scatter-hoarding passerine wintering in dominance-structuredflocks. We examined social influences on microhabitat selectionand spatial cache distribution at temporary feeders. Dominantadult males stored food closer to die feeder and at a greaterrate than did subordinates. When alone, the birds stored foodcloser to the feeder than when accompanied by conspecifics.Conifers were preferred over deciduous trees as cache trees.The subordinates cached more in die outer parts of branchesthan dominants. There were no significant differences in dierelative or absolute heights of die caches, nor in the verticalor horizontal hoarding niche breadths between dominants andsubordinates. We experimentally removed die dominants from dieflock for 90 min and recorded the behavior of die remainingsubordinates immediately after die removal. The removal resultedin a decrease in die hoarding distance of die remaining birds,indicating that die presence of dominants directly affecteddie behavior of subordinates and suggesting that kleptopar-asitismby dominants may be prevented by rarhing farther away. Withdie dominants removed, die subordinates cached at a greaterrate than before die removal. The decrease in die hoarding distanceand increase in die hoarding rate were die only significanteffects of die experiment, perhaps suggesting that, during ashort absence of dominants, die subordinates do not benefitfrom changing dieir caching microhabitat They might be excludedfrom those new, possibly safer, microhabitats after die dominantbird rejoins die flock.     

Free mobilization and low- to high-intensity exercise in immobilization-induced muscle atrophy

After 3 wk of immobilization, the effects offree cage activity and low- and high-intensity treadmill running (8 wk)on the morphology and histochemistry of the soleus and gastrocnemius muscles in male Sprague-Dawley rats were investigated. In both muscles,immobilization produced a significant(P < 0.001) increase in the meanpercent area of intramuscular connective tissue (soleus: 18.9% inimmobilized left hindlimb vs. 3.6% in nonimmobilized right hindlimb)and in the relative number of muscle fibers with pathologicalalterations (soleus: 66% in immobilized hindlimb vs. 6% in control),with a simultaneous significant (P < 0.001) decrease in the intramuscular capillary density (soleus: mean capillary density in the immobilized hindlimb only 63% of that in thenonimmobilized hindlimb) and muscle fiber size (soleus type I fibers:mean fiber size in the immobilized hindlimb only 69% of that in thenonimmobilized hindlimb). Many of these changes could not be correctedby free remobilization, whereas low- and high-intensity treadmillrunning clearly restored the changes toward control levels, the effectbeing most complete in the high-intensity running group. Collectively,these findings indicate that immobilization-induced pathologicalstructural and histochemical alterations in rat calf muscles are, to agreat extent, reversible phenomena if remobilization is intensified byphysical training. In this respect, high-intensity exercise seems morebeneficial than low-intensity exercise.

     

Identification of semi-domesticated reindeer (Rangifer tarandus tarandus,Linnaeus 1758) and wild forest reindeer (R.t. fennicus,Lönnberg 1909) from postcranial skeletal measurements

Reindeer bones are common finds from archaeological sites from prehistoric and historic Fennoscandia. The interpretation of the reindeer bone finds, however, is often hindered by the difficulty to separate the different subspecies of reindeer using the postcranial skeletal morphology. In this paper, skeletal measurements of modern semi-domesticated reindeer and wild forest reindeer are explored with multivariate statistical methods in order to find suitable methods for subspecies identification. The results are then applied to archaeological reindeer bone finds from Northern Finland and archaeological implications of the results are discussed.     

The role of competition and rarity in the restoration of a dry grassland in Finland

Abstract. Semi‐natural grasslands have become scarce throughout Europe. Preservation of their plant species requires either the maintenance of the existing grasslands or the creation of new ones. To study the establishment and regeneration ability of plant species typical of dry grasslands we laid out an experiment on a former arable field in central Finland. We compared the success of 13 grassland species both in a theoretical situation with minimal competition and in competition with weeds. More than half of the species used were regionally rare. As a group, grassland plants reached the highest cover in the experimental plots in which outside competition was minimised by weeding. However, the total cover achieved by their sward remained as low as 60% in the third growing season. The ability of grassland plants to regenerate and disperse on a small scale was therefore considered to be moderately poor. The short‐living species that were rare in the region where the study took place also had the greatest difficulties in establishment and survival in the experimental field. The preservation of rare species ‐ i.e. those species in the most urgent need of protection ‐ therefore appears to be difficult to achieve by habitat creation. Efforts should primarily be directed towards the maintenance of those habitats into which they have spread and become established naturally.     

Blood Pressure and Pulse Pressure during Long‐Term Weight Loss in the Obese: The Swedish Obese Subjects (SOS) Intervention Study

Objective: Recently we reported a complete relapse in the blood pressure (BP) of obese subjects despite a maintained 16% weight loss over 8 years. This relapse is now analyzed as a function of several variables. Pulse pressure (PP) is an independent risk factor of cardiovascular mortality. We now examine the development of PP in the obese and whether it can be modified by weight‐reducing gastric surgery. Research Methods and Procedures: A total of 1157 patients treated with gastric surgery and 1031 obese controls (body mass index of 41.0 ± 4.6 kg/m² [mean ± SD], age 48 ± 6 years) were followed for 5.5 ± 2.1 (range 3 to 10) years. To separate the effect of weight change from effect of time on BP, the patients were divided in cohorts based on follow‐up time. Results: Gastric surgery resulted in a maximum weight loss after 1 year that was followed by a moderate relapse. After 5.5 years, weight loss in the intervention group was 18 ± 11% of initial body weight. Very little weight change was seen in controls. Systolic BP decreased in the intervention group during the first 6 months but had relapsed to control values at last examination. The adjusted change in PP was +4.7 mm Hg in obese controls but +2.9 mm Hg in the intervention group (p < 0.001). Final BP values were more closely related to follow‐up time and ongoing weight increase than to initial body weight or initial weight loss. Discussion: Effects of time (aging) and weight change per year on BP can be separated. An early increase in PP could be observed in the obese. This increase could be modified by weight‐reducing gastric surgery.     

Biochemical characterization of CA IX, one of the most active carbonic anhydrase isozymes

Carbonic anhydrase IX (CA IX) is an exceptional member of the CA protein family; in addition to its classical role in pH regulation, it has also been proposed to participate in cell proliferation, cell adhesion, and tumorigenic processes. To characterize the biochemical properties of this membrane protein, two soluble recombinant forms were produced using the baculovirus-insect cell expression system. The recombinant proteins consisted of either the CA IX catalytic domain only (CA form) or the extracellular domain, which included both the proteoglycan and catalytic domains (PG + CA form). The produced proteins lacked the small transmembrane and intracytoplasmic regions of CA IX. Stopped-flow spectrophotometry experiments on both proteins demonstrated that in the excess of certain metal ions the PG + CA form exhibited the highest catalytic activity ever measured for any CA isozyme. Investigations on the oligomerization and stability of the enzymes revealed that both recombinant proteins form dimers that are stabilized by intermolecular disulfide bond(s). Mass spectrometry experiments showed that CA IX contains an intramolecular disulfide bridge (Cys(119)-Cys(299)) and a unique N-linked glycosylation site (Asn(309)) that bears high mannose-type glycan structures. Parallel experiments on a recombinant protein obtained by a mammalian cell expression system demonstrated the occurrence of an additional O-linked glycosylation site (Thr(78)) and characterized the nature of the oligosaccharide structures. This study provides novel information on the biochemical properties of CA IX and may help characterize the various cellular and pathophysiological processes in which this unique enzyme is involved.