Changes in total nitrogen, protein, amino acids and NH+4 in tissues of bilberry, Vaccinium myrtillus, during the growing season

Free amino acids and related compounds together with total nitrogen, total protein and soluble small-molecular nitrogen were analyzed quantitatively in monthly tissue samples from bilberry, Vaccinium myrtillus , from 15 May to 24 September 1985, in Oulu, northern Finland. Pronounced accumulation (at the millimolar level) of soluble low-molecular-weight nitrogen in the form of free amino acids was observed at the end of September. Arginine in particular accumulated in the rhizomes and older branches. Protein levels remained relatively constant. Mobilization of amino acids from winter storage into the growing tissues (buds) was evident in May.     

Meiofauna of springs in Finland in relation to environmental factors

The meiofauna was studied from springs in Finland which wascompletely ice-covered during the last glacial epoch. Of the31springs that were examined, 15 were in areas considered to bein anatural state and 16 had catchment areas subject toanthropogenicdisturbance from one of four sources: agriculture,inhabitation,gravel extraction or winter road de-icing with NaCl. The taxarecorded were a mixture of those already described fromepigeicwaters or groundwaters and some which may be regarded ascharacteristic of springs Statistical analysis revealeddifferencesin the meiofaunal taxa in relation to the water quality orcatchment area variables. Of the major meiofaunal groups thenematodes favoured springs influenced by agriculture,oligochaeteswere most tolerant of road de-icing, cladocerans and copepodspreferred springs in a natural state, ostracods couldwithstand theinfluence of road de-icing and gravel extraction, whilstdipteranlarvae could withstand the influence of agriculture.Oligochaetescomprised 13.4% of meiofaunal numbers. The most abundantspecieswas Aeolosoma quaternarium, which was most numerous insprings in a natural state, while Dero digitatapreferredeutrophic conditions. Harpacticoids comprised 14.1% ofindividualsand clearly preferred a natural state, Bryocamptusechinatusand Moraria brevipes being the most abundant species.Ostracods, of which the most abundant species was Potamocyprispallida, were the most numerous animal group, constituting21% ofthe meiofaunal population, and their numbers were greatest insprings influenced by road de-icing or gravel extraction.Dipteranlarvae, of which the majority were chironomids, comprised14.9% ofindividuals. The ostracods Potamocypris pallida andthreespecies of Candona and the harpacticoid Bryocamptuscuspidatus are new records for Finland.     

Wood ants prefer conifers to broadleaved trees in mixed temperate forests

1. Wood ants, species of the subgenus Formica s. str., are one of the most important groups of insects in forest ecosystems due to their high abundance and activity.
2. We assessed the foraging pressure of Formica polyctena and Formica rufa, two dominant wood ant species in the Białowieża Forest. In addition, we compared coniferous and mixed stands in these respects.
3. In mixed stands F. polyctena visited more trees per plot than F. rufa. F. polyctena might forage a larger area due to higher population sizes, which further confirms higher foraging pressure of F. polyctena in comparison with F. rufa.
4. In our study area, host trees of the ant–aphid mutualism were larger in diameter than nonhost trees. The ants also preferred trees situated closer to their nests. In both mixed and coniferous stands, the most visited tree species was Norway spruce. Thus, we can conclude that Norway spruce seems to be preferred by the ant. The decline of living spruce in the Białowieża Forest may endanger their food source and impact the vitality of ant colonies.

     

Aristolochia helix sp.nov. (Aristolochiaceae) from Thailand

A new species of Aristolochiaceae, Aristolochia helix , is described from Thailand and contrasted to its nearest ally, A. arenicola.     

Cortisol decreases the cellular concentration of translatable procollagen mRNA species in cultured human skin fibroblasts

The effect of cortisol on the cellular concentration of translatable procollagen mRNAs was studied in cultured human skin fibroblasts. Cortisol selectively decreased the amount of procollagen mRNAs, in comparison to the total mRNA activity, when the cells were grown in enriched medium conditions, i.e., with 10% newborn calf serum. The selective decrease was first observed after 6 h exposure to 1 μM cortisol. In depleted medium conditions, i.e., with 2% newborn calf serum, the initial response was a stimulatory one, followed after about 12 h by a decrease in the procollagen mRNA activity. The results suggest that the selective inhibitory effect of cortisol on the cellular concentration of translatable procollagen mRNA species needs an optimal serum concentration. Furthermore, the results give support to the hypothesis that the decrease in the procollagen mRNA concentration after cortisol administration is a secondary response, preceeded by the induction of some intracellular regulation system.     

Cytolysis and karyopyknosis in postmenopausal vaginal smears as markers of endometrial cancer, diabetes and obesity. Studies based on a ten-year follow-up

The vaginal cytology of 507 postmenopausal women was followed prospectively for ten years. Of the subjects, the 207 with cytolytic or karyopyknotic vaginal smears constituted the study group and the 300 with atrophic smears (indicating an absence of estrogenic activity) constituted the control group at the beginning of the follow-up. A woman whose initial smear was cytolytic usually had a cytolytic smear ten years later, which implies that high postmenopausal estrogenic activity is constitutional. Both at the beginning of the study and ten years later, the mean body weights were higher in the study group than in the control group. The mean karyopyknotic index and the prevalence of cytolytic smears were significantly higher among women with impaired glucose tolerance than among subjects with a normal glucose tolerance test. During the follow-up period, 3.6% of the women in the study group and 0.7% of the women in the control group developed endometrial cancer (P less than .02). The incidence of 3.6% of endometrial cancer is significantly higher than the corresponding age-specific incidence (P less than .001). We conclude that obese and/or diabetic postmenopausal women with cytolytic or markedly karyopyknotic vaginal smears exhibit a high intrinsic estrogen activity and may thus be at risk for endometrial cancer.     

Genetic variation of the Siberian tit Parus cinctus populations at the regional level: a mitochondrial sequence analysis

We studied the matrilinear genetic structure of the Siberian tit Parus cinctus by sequencing 911 bp of the mitochondrial control region of 56 birds from Fennoscandia and 3 from Yakutia, central Siberia, representing subspecies P. c. lapponicus and P. c. cinctus , respectively. One major haplotype comprised 35.7% of all birds and was present in all Fennoscandian populations. Sequence variation of 5 museum specimens from Norway fitted with the pattern of the present-day birds. The nucleotide diversity was 0.00205±0.00025 in the Fennoscandian population and no population structuring was detected. The star-like phylogeny suggests a recent expansion of the population size in the evolutionary time scale. A modern decline of the population size from 200 000 pairs to 50 000 pairs in Finland has resulted from cutting and fragmentation of old-growth forests, but the effects of this could not yet be detected in the mtDNA pattern. However, the nucleotide diversity differed among populations being the highest at Kuusamo, close to the Russian border. Conceivably, the gene flow maintained by the substantial migration of Siberian tits is sufficient to prevent differentiation of local populations in Fennoscandia. Presumably the large conservation areas in NE Finland and on the Russian side of the border contribute to the high genetic variation observed in the Kuusamo population. Comparison of the mtDNA phylogeny of the Siberian tit with the phylogenies of the great tit, the blue tit and the willow tit showed that the Siberian tit and some other non-migratory species of the foliage gleaning guild share similar post glacial histories in the western palaearctic.