Polyamines in early embryonic development: Their relationship to nuclear multiplication rate,cell cycle traverse,and nucleolar formation in a dipteran egg

Polyamine synthesis and accumulation were assessed from fertilization until gastrulation in a dipteran egg (Calliphora erythrocephala Meigen). Spermidine synthesis was activated immediately after fertilization, generating a broad spermidine peak during early cleavage. This period is characterized by the most rapid nuclear multiplication known from animal material. Cleavage consists of nuclear multiplication only, and the egg remains syncytial until gastrulation. After nine synchronous nuclear divisions with a cycle length of 10 min, the cycle length is gradually increased to 20 min during the subsequent four parasynchronous nuclear divisions. The spermidine level decreased in parallel with this decreasing rate of nuclear division. The interphase of the next nuclear cycle is remarkably prolonged and lasts for more than 90 min, i.e., until after the onset of gastrulation. It consists of an initial short S phase followed by a longer G₂ phase; G₁ is extremely short or absent. During this prolonged interphase, spermidine content showed a biphasic pattern of changes with peaks during S and late G₂. The S-phase peak also coincides with the first appearance of nucleoli during embryogenesis. The late-G₂-phase peak coincides with the period of rapid cytokinesis, during which all nuclei in the peripheral layer of the syncytium become separated by membranes forming a cellular blastoderm. The polyamine pattern is consistent with the idea that the polyamines play an important role in DNA replication and in cytokinesis as well as in nucleolar formation.     

Dental anxiety among middle-aged and elderly women in Sweden. A study of oral state,utilisation of dental services and concomitant factors

The aim of this project was to investigate dental anxiety and its expression in utilisation of dental services, oral health and oral symptoms. In a cross-sectional study of women's health in Göteborg (population 432,000), Sweden, 1016 women aged 38 to 84 years participated. This randomly selected population took part in a series of investigative procedures including medical and dental clinical examinations, interviews and questionnaires. Levels of dental anxiety were measured on the Corah Dental Anxiety Scale (DAS). The average DAS score obtained was 7.2. The study showed that older women were significantly less anxious than younger ones. Severe dental anxiety (DAS 15) was experienced by 3.9% of the participants. This frequency corresponds well with findings by Hällström and Halling in their analysis of data from the first Göteborg study of women's health 24 years ago. High levels of dental anxiety were correlated with longer intervals between dental visits, poorer oral function and aesthetics and a higher frequency of oral symptoms. Headaches were more prevalent in the younger age groups and a correlation with dental anxiety was revealed. Our previous studies have shown that symptoms such as tension headaches are prevalent among dental phobic patients and that they are reported to be reduced by therapy for dental fear. The clinical and radiographical examinations revealed a generally poorer oral status, with a statistically significant higher number of decayed teeth among women with high dental anxiety.     

Flavonoids and phenolic acids in adenostoma, a dominant genus of the californian chaparral

The flavonoid and phenolic acid pattern of Adenostoma fasciculatum and A. sparsifolium, two dominant, endemic species of the Californian chaparral, was analysed qualitatively and quantitatively. Adenostoma sparsifolium was found to secrete large amounts of lipophilic, unusually substituted flavonoids onto the leaf surface; A. fasciculatum produces five hydrophilic flavonol 3-O-glycosides of kaempferol, quercetin and isorhamnetin. The phenolic acid pattern differed quantitatively but not qualitatively between the species. The amounts of phenolic acids that could be detected within the leaves, leaf litter and soil beneath the shrubs seem too small to explain allelopathic effects as the main reason for the dominance of the two species.     

Kinetics of cyclic AMP in toad bladder

Tissue distributions of cyclic [³H]AMP and [¹⁴C]inulin in toad bladder were determined and their kinetics analyzed. We found that both the epithelial and the other cells of the toad bladder handcle cyclic AMP similarly. Moreover, we found that the distribution of cyclic AMP did not differ from that of inulin, an extracellular marker. Kinetic analysis suggests that the rate of coefficient of cyclic AMP metabolism is much larger than the exchange rate coefficient, which explains why distribution of both cyclic AMP and inulin are similar.     

Immobilization of enzymes based on hydrophobic interaction. I. Preparation and properties of a β-amylase adsorbate

Sweet potato β-amylase (α-1,4 glucan maltohydrolase, EC 3.2.1.2) was immobilized through adsorption onto an agarose gel to which nonpolar side chains had been introduced via ether bridges. The adsorbent showed evidence of saturation at an enzyme content of 35 mg per milliliter of packed gel. The adsorption was rapid and yielded a product whose operational stability depended on the initial content of β-amylase. Activity leakage was low. The relative activity of immobilized enzyme was inversely related to the amount of enzyme adsorbed to a given gel volume, having a maximal value of around 50% at low enzyme contents.     

Total degradation of 6-aminonaphthalene-2-sulphonic acid by a mixed culture consisting of different bacterial genera

Abstract A mixed bacterial culture consisting of eleven different strains was investigated in view of its ability to degrade 6-aminonaphthalene-2-sulphonic acid (6A2NS). Taxonomic characterization of the microorganisms showed that they belonged to three genera: Flavobacterium, Bacillus and Pseudomonas . None of the single strains could degrade 6A2NS. Some of 4–5-member co-cultures degraded it, but lost the ability in future subcultures. Only the mixed culture consisting of all eleven strains were stable and efficacious in degradation through numerous subcultures. The well-adapted mixed culture degraded the compound fast and without accumulation of intermediates, with a low increase in cell biomass and a high degree of mineralization.     

[3H] GBR-12935 Binding to Human Cerebral Cortex Is Not to Dopamine Uptake Sites

Abstract: The binding of the dopamine uptake inhibitor [³H] GBR-12935 to 16 regions of the human brain was investigated in competition experiments with increasing concentrations of GBR-12909, mazindol, and dopamine. The methodology used included a relatively high tissue concentration (8 mg/ml) and addition of 5 m M KCI in the assay buffer. GBR-12909 inhibited 80–90% of the binding in most regions, whereas dopamine only inhibited the binding in the striatum. Mazindol inhibited only part of the cortical binding at concentrations of >1 μ M , whereas the inhibition in the caudate and the putamen also contained a high-affinity component representing the dopamine uptake site. It is concluded that the [³H] GBR-12935 binding sensitive to GBR-12909 cannot be regarded as specific binding to the dopamine uptake site because the displaceable binding most likely is not related to the dopamine uptake site.