Showing papers by "University of Bergen published in 1978"

Determination of bacterial DNA in soil

Abstract: Two methods for the determination of DNA have been adapted for use on the bacterial fraction of an organic soil, obtained by fractionated centrifugation. The. soil contained about 1.1 × 10 10 bacteria g −1 dry weight when counted by fluorescence microscopy. One method was based on the reaction with 3,5-diaminobenzoic acid 2HCl, and the other on the specific reaction of the antibiotic mithramycin with double-stranded DNA. For the first method, about 8 × 10 8 cells were required and for the second, about 4 × 10 9 . The analytical results with the two methods agreed well. As an average of several determinations, an amount of 8.4 fg (10 −15 g) DNA per bacterial cell was found when the cells were counted by fluorescence microscopy. This is in the upper size range of bacterial genomes. showing that virtually all microscopically counted bacteria in this soil contain DNA. The total amount of DNA was about 90μg g −1 soil dry weight.

The sedimentary history of a debris‐flow dominated, Devonian alluvial fan–a study of textural inversion

Abstract: Karlskaret fan, with a radius of less than 11/2 km and dominated by debris-flow conglomerates, is one of numerous alluvial fans built out from the fault margins of Hornelen Basin (Devonian, Norway). The fan body is more than 170 m thick proximally, consists of four main coarsening-upwards segments and thins distally by a rising of its base and by a vigorous interfingering with very fine-grained sediments originating from an adjacent, impinging floodbasin system. Within the entire fan body, and within individual lobes, is a proximal-distal (and vertical) facies change from sheet-like, polymodal debris-flow conglomerates through matrix-rich conglomerates that are commonly distorted by loading, slumping and faulting, to remarkably sheet-like, matrix-rich granule sandstone of subaqueous debris-flow origin. Because the alluvial fan prograded into an actively aggrading floodbasin the primary fanglomerates, themselves having been subject to some sorting on the fan surface, incorporated large quantitites of very fine sediments. This inclusion of fines, effectively a textural inversion on the lower fan reaches, frequently led to remobilization and resedimentation of material beyond the fan toe. Anomalous maximum particle size/bed thickness relationships and a variety of graded textures within these resedimented beds suggest deposition in lacustrine areas of the adjacent floodbasin.

On the covering radius of binary codes (Corresp.)

Abstract: Upper bounds on the covering radius of binary codes are studied. In particular it is shown that the covering radius r_{m} of the first-order Reed-Muller code of lenglh 2^{m} satisfies 2^{m-l}-2^{\lceil m/2 \rceil -1} r_{m} \leq 2^{m-1}-2^{m/2-1} .

Multiphasic Uptake of Amino Acids by Barley Roots

Abstract: Concentration-dependence and other characteristics of uptake of 3H-labeled l-lysine, l-methionine and l-proline by excised roots of barley (Hordeum vulgare L.) were studied. Use of relatively short uptake and wash periods and low solute concentrations ensured good estimates of influx across the plasmalemma. Uptake in the range of 10−7M– 6.3 × 10−3M can be precisely represented by four or five phases of single, multiphasic mechanisms. The mechanisms appear to be relatively specific as judged from the competition by unlabeled analogues. Structural requirements for interaction of a compound with the uptake site for methionine are given, as are the effects of analogues on the phase pattern for this amino acid. There is no indication of separate uptake and transition sites for methionine or lysine. i.e. phase transitions seem in this case to be caused by binding of molecule(s) to the uptake site. Uptake, but not phase patterns, was highly pH-dependent. The optima were pH 5 for lysine, pH 3–5 (a broad peak) for methionine and about pH 5.5 for proline. Uptake of the three amino acids was strongly inhibited by 2,4-dinitrophenol. sulfhydryl reagents and deoxycholate.

The convergence angle in teeth prepared for artificial crowns.

Abstract: The bucco-lingual and mesio-distal convergence angles in vital and rootfilled teeth prepared for complete crowns were measured microscopically on 190 stone dies. In vital teeth the mean convergence angles varied between approximately 19 and 27 degrees. In rootfilled teeth the mean angles varied between 12 and 37.

Open field activity and avoidance behavior following serotonin depletion: a comparison of the effects of parachlorophenylalanine and electrolytic midbrain raphe lesions.

Abstract: Three experiments were performed in order to compare the behavioral effects of electrolytic destruction of the dorsal and median mesencephalic raphe nuclei (MR lesion) and parachlorophenylalanine (pCPA; 300 mg/kg, IP) administration. Forebrain 5-hydroxytryptamine (5-HT) was measured in all animals following completion of behavioral testing. In the first experiment open field behavior (one 50 min session) and two-way (shuttle) conditioned avoidance acquisition (50 massed trials) were examined 68–72 hr after vehicle or pCPA administration in rats which had received control operations or MR lesions two weeks earlier. Only the MR lesion and the MR lesion + pCPA groups evidenced increased open field activity and facilitated two-way avoidance learning. Although the reduction in forebrain 5-HT of the pCPA group (85%) was greater than in the MR lesion group (55%), the pCPA treated animals did not differ from the control group. In the second experiment animals were tested in the open field 24, 48 or 72 hr after pCPA treatment to determine its effects on activity level as a function of the time after injection. No differences between the vehicle and pCPA groups, however, were found. In the third experiment, the effects of pCPA (72 hr postinjection) on the acquisition of an unsignalled one-way avoidance response was examined. MR lesion rats tested in the same apparatus and with the same procedure repeatedly have been shown to be impaired in this task. The pCPA and vehicle animals, however, did not differ. Reductions in 5-HT following electrolytic MR lesions and pCPA administration, thus, produce different behavioral effects. MR lesions, but not pCPA treatment, result in (1) increased activity in a novel environment, (2) facilitated two-way conditioned avoidance learning, and (3) impaired acquisition of an unsignalled one-way avoidance response. These data support earlier studies suggesting that the behavioral effects of electrolytic MR lesions are not due primarily to their disruption of ascending 5-HT pathways. The role of 5-HT in avoidance conditioning and the regulation of activity level, furthermore, remains to be elucidated.

Partial molal volumes and compressibilities of carbohydrates in water

Abstract: The partial molal volumes and isentropic partial molal compressibilities of sugars, sugar alcohols, uronic acids, and some di- and trisaccharides in water have been measured at 25°C. The results suggest that the hydration of carbohydrates depends on the detailed stereochemistry of the solute and the way the solute molecule fits in the water structure. It seemed impossible at this stage to establish any additivity rules for the various functional groups or otherwise systematize the results.

Partial molal volumes and compressibilities of the homologous series of sodium alkylcarboxylates, R6COONaR13COONa, in aqueous solution

Abstract: The changes in partial molal volume (Δ V m ) and compressibility (Δ κ m ) in the formation of micelles have been determined at 25°C for the homologous series of sodium-alkylcarboxylates, R 6 COONaR 13 COONa. Δ V m has been determined by density measurements and by conductance measurements at different pressures. Δκ m has been evaluated from the conductance measurements and from ultrasound measurements. For each quantity the two independent methods of measurements gave consistent values. Δ V m and Δ κ m both increase with increasing chain length of the surfactant, but not in a linear manner. An analysis of the quantity Δ V m shows that the difference between successive values of Δ V m in the homologous series does not represent the group partial molal volume of the CH 2 group added to the micelle. The fraction of counterions associated with the micelles has been determined by EMF measurements, using a membrane electrode. This quantity was found to increase with increasing chain length.

Long-term biochemical and behavioral effects of p-chloroamphetamine in the rat.

Abstract: It is now well established that p-chloroamphetamine (p-CA) exerts longterm effects on central 5-hydroxytryptamine (5-HT, serotonin) neurons.', p-Chloroamphetamine has been shown to reduce the cerebral levels of tryptophan hydroxylase, 5-HT, and 5-hydroxyindoleacetic acid (5-HIAA) , synaptosoma1 high-affinity uptake of 5-HT, and 5-HT turnover for several months after its systemic administration in the rat.'-' These effects on 5-HT are similar to those observed after intraventricular administration of some of the hydroxylated tryptamines [5,6-dihydroxytryptamine (5,6-DHT), 5,7-dihydroxytryptamine (5,7-DHT)] and suggest a neurotoxic action of p-CA on brain indoleamine neurons. This hypothesis is supported indirectly by the findings of degenerative changes in perikarya located within midbrain regions rich in serotonergic cell bodies.% The midbrain raphe nuclei give rise to separate 5-HT systems that innervate different regions of the central nervous system. It has been suggested that p-CA affects only some of these regions, preferentially those that innervate forebrain structures.5 Several studies have demonstrated reduction in regional distribution and synaptosomal uptake 6 l lo of 5-HT in different forebrain regions after p-CA treatment. In the present study, we have investigated the effect of p-CA on 5-HT synaptosomal uptake in regions where the serotonergic innervation is known to differ with regard to its midbrain origin. It has been reported previously that blocking the 5-HT uptake mechanism may prevent the long-term biochemical effects of p-CA l1. l2 and p-CA-induced behavioral deficits.':', l4 Prompted by indications that such protection may not be equally effective in all regions of the central nervous system,'\" we have investigated the effects of p-CA on regional synaptosomal uptake in animals pretreated with a new 5-HT selective uptake inhibitor, zimelidine.12 The fact that p-CA reduces central 5-HT but not catecholaminesZ for long periods after a single injection has made it an interesting pharmacologic agent in studies of the role of serotonin in behavior. Previous studies on the behavioral consequences of 5-HT depletion have suggested a role of serotonin in various forms of locomotor activity and aversive behaviors.15 The present study reports some long-term effects on exploratory behavior and acquisition of an active avoidance response after p-CA treatment in the rat. To establish the serotonergic nature of these behavioral changes, some animals were pretreated with zimelidine before administration of p-CA.

Quaternary sediments in the northwestern part of the Barents Sea and their relation to the underlying Mesozoic bedrock

Abstract: A sedimentological study of Quaternary sediments from the northwestern part of the Barents Sea shows that their composition is controlled by the underlying Mesozoic bedrock and that very little sediment has been supplied from outside sources. The Quaternary sediments consist of Pleistocene glacial clays (moraines) and Holocene gravel, sand and mud, derived by erosion of the clay-rich moraines, which again have been derived from underlying Mesozoic rocks. On the shallow Spitsbergen Bank (30-100 m depth) we find a high energy facies of bioclastic carbonate sand and gravel and lag deposits of Mesozoic rock fragments from the underlying moraine. 14C-datings of the bioclastic carbonates (Molluscs and Barnacles) suggest that soft bottom conditions with Mya truncata prevailed in early Holocene time, succeeded by a hard bottom high energy environment with Barnacles in the last 2000-3000 years. This may be due to a southward movement of the oceanic polar front into the Spitsbergen Bank due to colder climate in Late Holocene (subatlantic) time, which at present day produces strong bottom currents down to 100 m depth. On the Spitsbergen Bank carbonate sedimentation has succeeded glacial sedimentation as a result of withdrawal of clastic sediment supply in Holocene time and high organic productivity because of upwelling. A similar mechanism may have been operating during earlier glaciations, i.e. in Late Precambrian time to produce an association of glacial and carbonate sediments although the biological precipitation was different at that time. In Late Precambrian time precipitation or carbonate by algaes may have occurred in colder water on the shelves due to higher saturation of carbonate in the sea water.

Nervous control of blood flow in the dental pulp in dogs

Abstract: Pulpal blood flow (PBF) was measured by H2-gas clearance in 30 dogs during electrical nerve stimulation, denervation and close intraarterial infusion of noradrenaline (NA). Electrical stimulation of the cervical sympathetic nerve and NA infusion always resulted in decreased PBF. The constrictor effect was reduced by α-blockers, but was never abolished or reversed to a vasodilation. Thus, no evidence for β-receptors in the dental pulp blood vessels was found. The fall in PBF produced by cervical sympathetic stimulation could be prevented by cutting the inferior alveolar nerve in the mandibular canal. Stimulation of the cut inferior alveolar nerve in the mandibular canal produced variable pulpal flow changes: Both a marked increase and decrease were measured. The flow changes during inferior nerve stimulation were unaffected by α-receptor blockade, while atropine reduced the vasoconstrictor respons or augmented the dilatory response. Electrical stimulation of the mandibular nerve before its entrance in the canal caused vasodilation, proposing a sensory antidromic axonreflex in the dental pulp. Sympathetic denervation had little or no effect on PBF, while cutting of the inferior alveolar nerve in the canal increased PBF in lower canine from 0.159 to 0.219 ml/min. g. The experiments show that pulp blood vessels of the dog may be controlled by both vasodilator and vasoconstrictor nerve fibers.

Effects of p-chloroamphetamine and 5,7-dihydroxytryptamine on the sexual behavior of gonadectomized male and female rats

Abstract: Treatment with the 5-HT neurotoxins p-chloroamphetamine (PCA, 2× 10 mg/kg) or 5,7-dihydroxytryptamine (5,7-DHT, 2×6 μg intracerebrally) stimulated the display of all aspects of sexual behavior, including ejaculations, by castrated male rats in the absence of testosterone (T) treatment and increased the behavioral sensitivity to a low level of T stimulation. The reduction of the (3H) 5-HT uptake after PCA treatment was more pronounced in the cortex than in the hypothalamus. 5,7-DHT treatment reduced the (3H) 5-HT uptake in the septum, hippocampus, amygdala, hypothalamus and cortex but the behavioral effects produced by the 5,7-DHT treatment could not be correlated to the biochemical effects in any of these brain areas. Since the behavioral effect of PCA appears to be stronger than that of 5,7-DHT, the 5-HT neurotoxins may exert their effect on sexual behavior in forebrain structures rather than in the hypothalamus. PCA treatment had a very small effect on mounting behavior but 5,7-DHT treatment stimulated the display of mounts and intromission patterns by ovariectomized female rats given no hormone treatment. Neither PCA nor 5,7-DHT had any effect on lordosis behavior tested before and after treatment with estradiol benzoate alone or in combination with progesterone. The observations support the conclusion that 5-HT is involved in the control by T of sexual behavior in male rats, but argue against a role of 5-HT in the neural control of lordosis behavior.

Filter characteristics of appendicularian food catching nets

Abstract: Scanning electron micrographs reveal extensive filter surfaces in the external food catching net of planktonic appendicularia. This filter consists of crossing arrays of filaments about 0.04 μm thick and pores about 0.24×0.07 μm wide. The open area fraction is above 50%. The filter probably enables the appendicularia to feed efficiently on particles much smaller than bacteria.

The spring phytoplankton bloom in Lindåspollene, a land-locked Norwegian fjord. II. Biomass and activity of net- and nanoplankton

Abstract: From February 24 to April 24, weekly samples were collected at fixed depths at one station in Lindaspollene, a land-locked Norwegian fjord. Adenosine triphosphate (ATP), chlorophyll a, phaeophytin, 14C assimilation, and respiratory activity [electron transport system (ETS) activity] were measured in the net- (>30 μm) and nanoplankton. Netplankton contained on the average 48% of the total chlorophyll a and 56% of the ATP, but contributed only 7% to the total carbon assimilation and 11% to the ETS activity. The assimilation numbers for net- and nanoplankton ranged from 0 to 1.2 and from 1.5 to 13.2, respectively. At the oxygen/hydrogen sulphide interface, high concentrations of ATP, but not of chlorophyll a, were found in the nanoplankton fraction. Netplankton algae grew actively only in the first phase of the bloom, and nanoplankton predominated later, apparently due to low nutrient concentrations. During the bloom, Skeletonema costatum made up the main part of the biomass. The number of cells in the chains decreased throughout the bloom, possibly reflecting the lowered silicate content. It appeared that only nanoplankton were grazed by zooplankton, while netplankton sank to the bottom and represented input to the benthos.

Multiple-satellite studies of magnetospheric substorms - Plasma sheet recovery and the poleward leap of auroral zone activity

Abstract: Particle observations from pairs of satellites (Ogo 5, Vela 4A and 5B, Imp 3) during the recovery of plasma sheet thickness late in substorms were examined. Six of the nine events occurred within about 5 min in locations near the estimated position of the neutral sheet, but over wide ranges of east-west and radial separations. The time of occurrence and spatial extent of the recovery were related to the onset (defined by ground Pi 2 pulsations) and approximate location (estimated from ground mid-latitude magnetic signatures) of substorm expansions. It was found that the plasma sheet recovery occurred 10 - 30 min after the last in a series of Pi bursts, which were interpreted to indicate that the recovery was not due directly to a late, high latitude substorm expansion. The recovery was also observed to occur after the substorm current wedge had moved into the evening sector and to extend far to the east of the center of the last preceding substorm expansion.

On the Use of Pyranometers in the Study of Spectral Solar Radiation and Atmospheric Aerosols

Abstract: The zero-point deviation of Eppley precision spectral pyranometers is considered for different types of Schott filter glass hemispheres. It is found that the zero-point deviation may significantly affect the measurements of spectral global and diffuse fluxes, and may also lead to considerable errors in the estimates from pyranometer data of the influence of atmospheric aerosols on shortwave radiative transfer. When the zero-point deviation is properly corrected for, however, precision spectral pyranometers may yield precise measurements of even very low spectral irradiances.

Adaptative changes in the small intestine following bypass operation for obesity. A radioglocal and histological study.

Abstract: Roentgenographic follow-up studies were made in 7 patients before and at different intervals after jejuno-ileal bypass operation. Length measurements were made by a modified intubation technique, and intestinal transit time was estimated after a standardized contrast meal. Microscopical measurements of mucosal biopsies were done in 6 patients before, and 6 and 12 months after, the operation. A significant increase in the diameter of the functioning small intestine was found 4 months after the operation; in repeated investigations up to 18 months no further dilatation occurred. A gradual increase in intestinal length was demonstrated up to 18 months postoperatively. This compensatory growth appeared earlier and was most pronounced in the ileal part of the functioning intestine. Whereas the emptying time of the stomach and the intestine were unchanged, an increase in transit time was found 12 and 18 months after the operation. Measurements of mucosal biopsies showed an increase in mean villous height of the...

Ultrastructural study of early dental plaque formation.

Abstract: Initial Colonization and early plaque formation were studied using hydroxyapatite splint segments attached to buccal surfaces of maxillary molar and premolar teeth in six young adults given a low-sucrose diet Segments were removed at intervals of 2, 4, 6, 12, 24 and 48 hr Bacteria were first regularly seen in 4 or 6 hr specimens where they occurred as individual cells or as small groups of cells No structures resembling preformed aggregates or hemispherical bacterial “globules” could be demonstrated The bacteria most frequently attached to the pellicle surface diectly by their cell wall and gram-positive cocci were most abundant Another mode of bacterial attachment to pellicle was by means of fine bifbrils or coarser thread-like structures Occasionally organisms were seen attaching to apatite surfaces without interjacent pellicle material and sometimes they appeared to be completely embedded in the pellicle Bacteria colonizing on epithelial cells regularly displayed a “fuzzy coat” Extensions of organic material from the pellicle surface sometimes made it difficult to distinguish between pellicle and plaque matrix No clear indication of bacteria metabolizing the pellicle was seen Trilaminar vesicles probably originating from the surface of degenerating cells were especially abundant in areas with Gramnegative bacteria In areas with Gram-positive cells the amount of plaque matrix was greater and a number of cells displayed surface threads The outer surface of the plaque ordinarily did not show a layer of extracellular organic material although a granular laer could be seen in local areas These findings lend support to a concept of plaque formation as a sequential build-up resulting from selective attachment and growth of individual organisms rather than resulting from attachment of aggregates of bacteria or a passive entrapment of organisms in a matrix

The Structure and Mineralization of the Carapace of the Crab (Cancer pagurus L.) 2. The exocuticle

Abstract: The exocuticle of the dorsal carapace of the intermoult Cancer pagurus was studied by means of light microscopy, electron microscopy, and contact microradiography. In the exocuticle a 5-15 μm wide highly mineralized external zone was seen where prisms were not present. The cross-sectional shape and diameter of the prisms varied. The prisms were separated by interprismatic areas varying in width and in degree of mineralization. With increasing width of the interprismatic areas the diameter of the prisms decreased. The prism-less external zone may be the result of complete mineralization of the prisms. The pore canals of the exocuticle were circular in cross section and present both within the prisms and within the interprismatic areas. The lamellar system of the exocuticle was built up by layers of horizontal fibrils which were interconnected by vertical or oblique fibrils. The minerals of the external prism-less zone occurred as aggregates of crystalline matter or as large brick-like structures. Crystal edge lengths up to 300 nm were measured. In well mineralized interprismatic areas aggregates of crystals and relatively large crystals were observed. In poorly mineralized interprismatic areas small plate-like crystals occurred. Occasionally a prism-less zone was seen near the exocuticle/endocuticle junction.

Identification of mononuclear cells in situ in skin lesions of lichen planus

Abstract: SUMMARY Cryostat sections of lesional skin of lichen planus were examined for receptors for sheep erythrocytes (T lymphocytes), Fey and C3b receptors (B lymphocytes and macrophages) and C3d (B lymphocytes). The indicator cells were applied using a closed chamber technique. The combination of the closed chamber technique and treatment of the sheep erythrocytes with a strong sulphydryl reagent enabled us to detect T lymphocytes by their membrane receptors in situ. T lymphocytes were the predominant mononuclear cells in the dermal infiltrate, with less macrophages and only a few B lymphocytes.