Antibodies against Toxoplasma gondii in Fennoscandian reindeer - association with the degree of domestication

To measure the prevalence of antibodies against Toxoplasma gondii in Fennoscandian reindeer, we examined 2577 serum samples collected between 1993 and 1996 from slaughtered reindeer from Finnmark county, Norway, and from several locations in Finland. The overall prevalence in this sample was 0.9%, and the titres of the seropositives in the Direct Agglutination Test (DAT) were between 1:40 and 1:162000. Logistic regression associated seropositivity with the age of the animal, the odds ratio (OR) of adults was four when compared with calves. Seropositivity was also positively associated with corral feeding, which was used in the analysis as an indicator of domestication. No significant association was found with sex, or the frost sum of the pasture area.     

Markers for the gene ob and serum leptin levels in human morbid obesity

Leptin, the product of the ob gene, reduces body fat in genetically obese animals and circulates in elevated concentrations in the blood of obese patients. Polymorphic markers situated in the proximity of the human ob gene have recently been suggested to be linked to morbid obesity. We have studied the possible association between the microsatellite markers near the ob gene and morbid obesity in 252 morbidly obese patients with a mean body mass index (BMI) of 43 ± 7 kg/m², and 151 lean controls with a mean BMI of 22 ± 2 kg/m², and searched for linkage of these gene markers to obesity in 76 affected sib-pairs (BMI ≥ 32). No significant association was observed between any of the eight microsatellite markers and morbid obesity, and affected-sib-pair analysis failed to show linkage of three selected ob gene markers to obesity in the sibships. There was a strong positive correlation between serum leptin levels and BMI in morbidly obese patients; a carrier status for either of the two most prevalent alleles of the microsatellite marker D7S530 in the vicinity of the ob gene was associated with serum leptin levels in the obese subjects. Two of the markers (D7S2519, D7S649) showed a significant relation to the weight-losing response to a 16-week very-low-calorie dietary intervention. We have thus been able to confirm a tight relationship between serum leptin and body mass but have found no evidence for genetic linkage of the ob gene markers to morbid obesity in a population considered to represent a genetic isolate and to be an ideal model for studies of complex disorders. Received: 25 October 1996 / Revised: 4 December 1996     

Severe photobiont injuries of lichens are strongly associated with air pollution

The photobiont ultrastructure of the epiphytic lichens Bryoria fuscescens and Bryoria fremontii was studied along the pollution gradient from two Cu-Ni smelters in Nikel and Monchegorsk in northern Finland and north-western Russia. The relationship between ultrastructural characteristics of B. fuscescens and environmental factors (i.e. climate, atmospheric SO₂ and bark element concentrations) was studied by using a principal component analysis (PCA) aiming to assess the air quality in a northern environment. Based on PCA, increased plasmolysis and mitochondrial changes in the Trebouxia photobiont were significantly correlated with elevated pollutant concentrations. Degenerated cells, showing altered chloroplasts and electron-translucent pyrenoglobuli, occurred in lichens growing 35–50 km from the Monchegorsk smelter. Cell wall and cytoplasmic lipid volumes, and size of pyrenoglobuli, positively correlated with the distance from the Monchegorsk smelter. Vacuoles and electron-opaque vacuolar deposits were significantly increased at the Finnish site in the vicinity of a pulp mill. Swelling of mitochondrial cristae and thylakoids showed little correlation with environmental factors, but indicated of initial stage of injuries and were observed at several slightly polluted sites in northern Finland and north-western Russia. The results suggest that the severe photobiont injuries of lichens are strongly associated with poor air quality.     

Mechanical efficiency of locomotion in females during different kinds of muscle action

The mechanical efficiencies (ME) of pure positive and pure negative work as well as of stretch-shortening cycle (SSC) exercise were investigated with a special sledge apparatus. The subjects were 20 young females who performed six different types of submaximal exercise: two of pure concentric exercise (positive work), two of pure eccentric exercise (negative work) and two SSC exercises. The work intensities were determined individually, from the recordings of distance obtained during a single maximal concentric exercise. Each exercise involved 60 muscle actions lasting a total of 3 min per testing condition. The MEs of pure positive work with intensities of 30% and 60% maximum (C30 and C60 respectively) were 15.5%, SD 2.6% and 14.3%, SD 1.9%, respectively. In pure negative work, when the dropping heights were 20 cm (E20) and 80 cm (E80), MEs were 28.4%, SD 6.9% and 47.9%, SD 10.1%, respectively. In SSC-exercise, the MEs during the positive phase of the take-off were 31.3%, SD 6.3% (E20/C90) and 35.0%, SD 7.0% (E80/C69). The total MEs in SSC-exercise were 29.1%, SD 4.0% (E20/C90) and 40.1%, SD 5.2% (E80/C60 x 100). In pure negative work, the increased stretching velocity increased the value of ME. In the concentric phase of SSC-exercise, the integrated electromyographic activity (iEMG) of vastus lateralis (VL) and vastus medialis (VM) muscles were lower (P less than 0.05) than in pure concentric work, when the mechanical work was the same (C60 vs E80/C60). During pure eccentric work, iEMGs were lower in comparison to the eccentric phase of SSC-exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Effect of Exercise on Blood Parameters in Standardbred and Finnish-Bred Horses

Serum enzyme activities, albumin, protein, urea, cholesterol, triglyceride, free fatty acid, glucose and lactate concentrations as well as hematocrit values were measured in standardbred and Finnish-bred horses at rest and after (i) a short controlled exercise and (ii) a trotting competition. There were no breed differences in the enzyme activities at rest and the 2 breeds responded in the same manner to the exercise. Only after the race proper significant increases in the enzyme activities were found. The activities rose more in the standardbred horses than in the Finnish-bred horses. Urea and cholesterol concentrations did not change after either exercise. Protein and albumin concentrations as well as hematocrit values increased significantly after the exercise. At rest hematocrit values were significantly higher in the standardbred horses and the difference persisted throughout the exercise. After the race proper also albumin and protein concentrations were higher in the standard-bred than in the Finnish-bred horses. Free fatty acid and triglyceride concentrations increased significantly during the exercise. Although glucose and lactate concentrations increased in both breeds, the behaviour of these parameters differed. Glucose concentrations remained increased for a longer period and the recovery from the increased lactate level was faster in the standardbred than in the Finnish-bred horses. The observed differences suggest that the standardbred horses have higher anaerobic capacity than the Finnish-bred horses.     

The effect of the water-lily beetle, Galerucella nymphaeae, on leaf production and leaf longevity of the yellow water-lily, Nuphar lutea

SUMMARY. 1. The effect of the water-lily beetle, Galerucella (= Pyrrhalta ) nymphaeae (L.), (Coleoptera, Chrysomelidae), on the leaf production and leaf longevity of the yellow water-lily, Nuphar lutea (= N. luteum ) (L.) Sibth. & Sm., was studied experimentally in southern Finland during one growth season.
2. Twelve cages, each containing a single rosette of the water-lily, were established in the lake during May. Two treatments were randomly applied to cages: (i) control (herbivory not allowed), and (ii) fifty beetles added at the beginning of the season. Leaves were marked individually and the production of new leaves was followed until October.
3. In both treatments the production of floating leaves continued until the end of August but declined towards the end of summer. Herbivory did not affect the number of leaves produced, i.e. the plants did not compensate for the loss of leaves.
4. Leaf longevity was reduced dramatically (up to —60%) when herbivores were present. Leaves that emerged during the most intense period of larval growth had a life-span one-third of that of the control group.     

A century of community ecology: How much progress?

Much of the apparent progress in community ecology amounts to little more than re-inventing the wheel, albeit with technical improvements. Many central ideas in the field were stated by A.K. Cajander at the turn of the century. Thereafter, community ecology has moved back and forth between competition-centered and individualistic views of community structure. The chief problems have probably been inappropriate methodology (lack of rigorous formulation and/or critical experimental testing of theories) and a tendency to work only on subcommunities that are delimited by taxonomic criteria. Although these problems are beginning to be remedied, a new one has emerged: ignorance of history and a tendency to re-invent old ideas under new, flashy names. This problem is potentially as dangerous as the old ones and must be tackled by improving our first-hand contact with the classics in our field.     

BVOC Emissions From a Subarctic Ecosystem,as Controlled by Insect Herbivore Pressure and Temperature

Ecosystems - The biogenic volatile organic compounds, BVOCs have a central role in ecosystem–atmosphere interactions. High-latitude ecosystems are facing increasing temperatures and insect...