Marianne Andersson

Wolf Canis lupus Predation on Moose Alces alces and Roe Deer Capreolus capreolus in south-central Scandinavia

During 1988–1992, 684 scats were collected throughout the year in the territory of the only reproducing family group (mean five individuals) of wolves Canis lupus in Scandinavia. Moose Alces alces, roe deer Capreolus capreolus, and badger Meles meles constituted the three most important prey species, and hair from them was found in 52%, 50%, and 19% of scats, respectively. When compensating for different area/volume ratios in prey species of different size, these three species were estimated to constitute 97% of the biomass ingested. The proportions of moose, roe deer, and badger were 66%, 27%, and 8% by mass, and 25%, 52%, and 23% by number, respectively. Young-of-the-year dominated two samples of dead moose (51% of 65 killed by wolves; 43% of 155 killed by hunters), but no significant differences between the samples were found in any age class. Wolves killed significantly more female moose (76%) than hunters (53%), and among wolf-predated moose, no male was older than two years. Mean winter density of moose and roe deer in the wolf territory (523 km2), estimated by fecal pellet group counts, was 1.5 moose and 0.4 roe deer/km2. Moose density decreased slightly at the end of the study, but it was estimated that wolves killed only about 5% of the moose population each year and that this could be compensated for by a decrease of about 10–20% in the hunter kill. In spite of a high predation pressure from wolves, in addition to predation from an increasing lynx Lynx lynx population, the density of roe deer increased threefold. It is concluded that the future predation pressure on moose may be more pronounced if the density of wolves increases, and roe deer may be more affected by predation when the present favourable ecological conditions cease.

Early increase in diadenosine tetraphosphate in regenerating rat liver

Diadenosine tetraphosphate (Ap4A), a candidate for a signal molecule in the induction of DNA synthesis, was measured in regenerating livers of young adult rats at 12 and 24 h and of older rats at 24 h after partial hepatectomy. dATP and dTTP levels, which indicate the degree of proliferation in the livers, were determined by high-performance liquid chromatography and an enzymatic method, respectively. The Ap4A levels were increased in the beginning of DNA synthesis. In young rats the levels were about 140% of those of unoperated rats and in older rats about 300%. This increase was considerably smaller than that found in another study comprising two regenerating rat livers excised 20 h after partial hepatectomy, but still supports the hypothesis that Ap4A might take part in the onset of proliferation. The greater Ap4A increase in older rats may suggest a possible need for a stronger triggering mechanism to start proliferation in aged tissue. However, the experiments do not prove a function for Ap4A in the induction of DNA synthesis and it cannot be excluded that Ap4A is a product of an independent reaction.

Isotachophoretic and HPLC determination of nucleotides in rat liver cell nuclei isolated by non-aqueous technique

Rat liver whole cells and cell nuclei were prepared by a non-aqueous technique (glycerol). The nuclear preparations were of different purity as determined by RNA/DNA ratios (0.17-1.60) and accordingly were divided into 3 subgroups (mean values 0.29, 1.04 and 1.48). RNA nucleotides were separated by isotachophoresis and HPLC and calculated per mg DNA. Two of the nuclear subgroups (RNA/DNA = 1.04 and 1.48) had significantly elevated nucleotide values in relation to RNA/DNA. UDP-N-acetylhexosamine/DNA, on the contrary, was reduced in conformity with RNA in the preparations. Our findings may indicate different nucleotide concentrations in different parts of the cell.

Intracellular compartmentation of diadenosine tetraphosphate (Ap4A) and dTTP in rat liver

1. The intracellular compartmentation of diadenosine tetraphosphate (Ap4A) and of dTTP was studied in rat liver cells using non-aqueous glycerol for the isolation of cell nuclei. 2. This method allows a stepwise removal of cytoplasm from the nuclei. 3. The decrease in Ap4A or dTTP during the process was compared to the simultaneous decrease in RNA, which was taken to represent the cytoplasm. 4. In regenerating liver excised 24 hr after partial hepatectomy, Ap4A was almost equally distributed between the nucleus and cytoplasm. 5. In livers from unoperated control rats, the nuclear concentration of Ap4A was slightly elevated compared to that of whole cells. dTTP was only investigated in regenerating liver. 6. Significantly higher concentrations were found in the nuclear fractions. 7. The purest nuclei contained about 26% of whole cell levels of dTTP, while their RNA values had decreased to 7% of the whole cell RNA. 8. Considering that the liver cell nucleus comprises about 7% of the entire cell mass, a nuclear dTTP concentration of 26% indicates significantly higher dTTP levels in the nuclear compartment than in the cytoplasm of regenerating rat liver cells.

Nucleic acid labeling with [3H]orotic acid and nucleotide profile in rats in protein deprivation, enteral and parenteral essential amino acid administration, and 5-fluorouracil treatment

Rats were fed a 0% casein diet for 1 week, with or without enteral or parenteral administration of essential amino acids, or a 25% casein diet, in one group supplemented with 5-fluorouracil treatment. Ninety minutes before sacrifice the rats were given a tracer of [3H]orotic acid. Incorporation into the acid soluble fraction, RNA, and DNA was determined in liver, small intestine, bone marrow, and kidney. Nucleotide profile was examined in liver and intestine. Protein deficiency caused inter alia a decrease in body weight; a decrease in RNA/DNA ratio and an increase in the specific RNA labeling in liver and kidney; an altered nucleotide profile in the liver; an increase in the nucleotide/DNA and RNA/DNA ratios and a decrease in the specific labeling of the acid soluble fraction, RNA, and DNA in the bone marrow. These changes were prevented to the same extent by giving essential amino acids, either orally or intravenously. The minor changes in intestinal nucleotide profile in protein deprivation were prevented to a slightly larger extent by amino acids orally than parenterally. 5-Fluorouracil treatment gave a decrease in the RNA/DNA ratio in the liver and kidney but an increase in the nucleotide/DNA and RNA/DNA ratios in the bone marrow. Nucleotide profiles were unaltered. The amount of DNA per gram of tissue decreased in bone marrow and increased in kidney. Parenteral administration per se resulted in almost no changes.

Periodate-methylamine degradation of ribonucleotides in rat liver extracts in comparison to extracts of cultured cells

Periodate-methylamine degradation of ribonucleotides, which enables separation of deoxyribonucleotides in cell extracts by high-performance liquid chromatography, was tested on the acid-soluble fraction of L1210 cells, Ehrlich ascites tumor (ELD) cells, liver tissue, and liver cell nuclei. It was shown that dTTP, dCTP, and dATP could be clearly separated in L1210 and ELD extracts. In samples from liver tissue, however, dTTP coeluted with another compound, the dCTP peak often eluted very close to another peak, and only dATP separated quite satisfactorily. Furthermore, extracts from liver cell nuclei, isolated in glycerol, were not directly susceptible to periodate oxidation. This problem can be avoided by use of a different procedure for the isolation of cell nuclei.

Trace element analysis by PIXE in liver samples from dogs with chronic active hepatitis and liver cirrhosis

Abstract Trace element levels of liver samples obtained from necropsied dogs suffering from hepatitis and/or liver cirrhosis were determined by PIXE. Two different techniques for preparation of the samples were compared: the pellet press method and wet digestion. Both methods gave similar results, but the pellet press method was chosen for the subsequent routine analyses because of its simplicity due to few preparation steps and little risk of contamination. Preliminary results indicate elevated levels of Cu in chronic hepatitis and cirrhosis. In hereditary copper-induced hepatitis (Bedlington hepatitis) Fe and Br levels were increased as well.

Variation of incorporation of [3H]orotic acid into the nucleotide and RNA fractions of different parts of the same liver lobe in the rat

1. Anaesthetized rats were given [3H]orotic acid either intraperitoneally or via a catheter into the hepatic artery with or without degradable starch microspheres. 2. The radioactivity in the acid soluble and RNA fractions of five pieces of the left lateral liver lobes was determined. 3. A variation of the distribution of the precursor into the different parts of the same liver lobe was shown. 4. This variation was most pronounced (3000-17,000 cpm/micrograms in the acid soluble fraction) when the precursor was administered via the artery and without microspheres. 5. The correlation between the radioactivity in the acid soluble and RNA fractions within each liver piece was 0.85, 0.90 and 0.75 in the three groups respectively. 6. It is suggested that the variation of the distribution depends on circulatory differences within the liver.

Diadenosine tetraphosphate (Ap4A) levels in hl-60 cells during differentiation into granulocytes and monocytes

1. Diadenosine tetraphosphate (Ap4A) levels were determined in HL-60 cells differentiating into granulocytes or monocytes after treatment for 0-7 days with retinoic acid (RA) or 4-beta-phorbol-12-myristate-13-acetate (PMA) respectively. 2. The levels increased significantly compared to untreated control cells within 2 days and then declined again. 3. In RA treated cells the levels finally decreased far below those of untreated HL-60 cells and became equal to those found in human granulocytes. 4. PMA treatment had no effect on Ap4A levels in human granulocytes. 5. A possible interaction between Ap4A and ADP-ribosyl transferase is discussed.