Ferritin enhances production of DNA strand breaks by 6-hydroxydopamine,ascorbic acid and H2O2 in CCC PM2 bacteriophage DNA

Damage of CCC PM2 DNA by 6-hydroxydopamine (6-OHDA) and ascorbic acid (AA), compounds that are both able to release iron from ferritin, was significantly enhanced in the presence of ferritin. H₂O₂, a product of 6-OHDA autoxidation, did not induce DNA strand breaks in the absence of ferritin and only to a minor extent in the presence of ferritin. DNA damage by 6-OHDA and AA could be reduced by the hydroxyl radical scavenger mannitol, the iron chelator desferrioxamine, and, partly, by a combination of superoxide dismutase and catalase. These inhibitory effects were clearly less pronounced in the presence of ferritin. Ferritin obviously played an important role as a source of iron in the pro-oxidative processes of 6-OHDA and AA. These features might be of importance in cancer therapy since many tumor cells contain elevated ferritin levels.     

Reproduction and social rank in female stumptail Macaques (Macaca arctoides)

Reproductive physiology was studied in female stumptail macaques. Initially the monkeys were housed indoors (individually and in small groups) and later as one large (92 individuals) social group in an outdoor cage. Most data were collected during the 4-year outdoor period. Plasma progesterone determination in blood samples taken at weekly intervals allowed estimation of ovulation and conception dates. The age at first ovulation (X =3.73 years) was positively correlated with body weight at 3 years of age. The average age at first birth was 4.90 years. Gestation lengths averaged 176.6 days. Following a live birth ovulations returned after a mean interval of 11 months but following an abortion or still birth this interval was 1 month. Usually a number of ovulatory cycles (X =2.37) preceded a conception. Interbirth intervals (IBIs) in the outdoor cage (X =619.4 days) were significantly longer than IBIs during the indoor period (X =523.1), because indoors the infants were weaned at the age of 7 months, while outdoors weaning occurred more naturally. IBIs following abortions or still births (X =291.9 days) were significantly shorter than IBIs following live births. Age at first ovulation, age at first birth, IBIs, and infant production rates were not correlated with dominance rank. Ovarian cycle lengths (X =30.2 days, mode = 28 days) were comparable to previously reported data from laboratory-housed stumptails. No systematic seasonal fluctuations were found in the onset of sexual maturity, in ovarian cycle lengths, in copulation frequencies, and in distribution of births.     

Effect of pH on binding of agonists and antagonists to rat heart muscarinic receptors.

Insulin, epidermal growth factor (EGF), platelet-derived growth factor, multiplication-stimulating activity and 10% foetal-calf serum each stimulated the phosphorylation of a cytosolic Mr-22000 acidic heat-stable protein in Swiss mouse 3T3-L1 adipocytes. Phosphorylation of this protein was not stimulated by isoprenaline or dibutyryl cyclic AMP. The effect of insulin was maximal (3-fold increase) by 10 min; half-maximal stimulation was observed at 70 pM-insulin. Both [32P]phosphoserine and [32P]phosphothreonine residues were present in the Mr-22000 protein after insulin- and growth-factor-stimulated phosphorylation, but no [32P]phosphotyrosine. The major site of insulin- and EGF-stimulated phosphorylation appeared to be a threonine residue, in contrast with previously studied insulin-stimulated phosphorylation of serine residues. Insulin treatment appeared to result in a shift of the protein toward the anode on isoelectric focusing. Insulin and EGF present simultaneously did not lead to phosphorylation beyond that seen with each hormone singly. We surmise that insulin, EGF and perhaps other growth factors may activate a common protein kinase or inhibit a common protein phosphatase in 3T3-L1 adipocytes which acts on the Mr-22000 protein.     

Growth rate stimulation of marine pseudomonads by thiosulfate

The oxidation of thiosulfate to tetrathionate exerts a definite growth rate stimulation in glucose, acetate, and yeast extract cultures of some marine pseudomonads. The failure to find this effect in earlier studies with terrestrial isolates may lie in the particular conditions used in the present experiments (constant pH, high ratio of thiosulfate to organic substrate) or in the different metabolic characteristics of the marine isolates.Contribution No. 3220 from the Woods Hole Oceanographic Institution.     

Free Radical Mediated Cytotoxicity of Desferrioxamine

Toxic effects of desferrioxamine (DFO) upon cell growth were assayed with continuous bromodeoxyur-idine (BrdU) labeling and bivariate ethidium bromide/Hoechst 33258 Row cytometry. At 5% oxygen DFO caused a dose-dependent inhibition of cell growth. which was potentiated at 20% oxygen. and by cumene hydroperoxide but not by paraquat. An irreversible arrest in the GZ phase of the cell cycle was the cell-kinetic mechanism underlying this growth inhibition. The G2 arrest was not dependent upon the BrdU concentration in the medium, thus ruling out a direct attack of a free radical on thymidine residues. The observed cytotoxicity of DFO cautions against its use in the treatment of conditions of elevated oxidative stress.     

Leaf thionins, a novel class of putative defence factors

Leaf thionins of barley have been identified as a novel class of highly abundant polypeptides with antifungal activity, which are present in walls and vacuoles of barley leaf cells. Similar thionins occur not only in monocotyledonous but also in various dicotyledonous plants. The leaf thionins of barley are encoded by a complex multigene family, which consists of at least 50–100 members per haploid genome. The toxicity of these thionins for plant pathogenic fungi and the fact that their synthesis can also be triggered by pathogens strongly suggest that leaf thionins are involved in the mechanism of plant defence against microbiol infection.     

Rat PHI, PHI-GLY and PHV (1-42) stimulate adenylate cyclase in six rat tissue and cell membranes

PHI and the two C-terminally extended forms PHI-GLY and PHV(1-42) coexist in rat tissues. We compared the relative potency and efficacy of these three PHI forms and of VIP to stimulate adenylate cyclase activity and, when feasible, to occupy VIP receptors in six rat tissue and cell membranes. With the exception of lung membranes, all three PHI forms were markedly less potent than VIP but all were systematically as efficacious. PHI-GLY and PHV(1-42) were never more potent than PHI itself and their relative potencies revealed four spectra, depending on the membrane preparation tested: 1) PHI = PHI-GLY = PHV(1-42) in hepatic, pulmonary and pancreatic membranes; 2) PHI greater than PHV(1-42) = PHI-GLY in membranes from circulating lymphocytes; 3) PHI = PHV(1-42) greater than PHI-GLY in membranes from the thymocyte cell line 51E; and 4) PHI greater than PHI-GLY = PHV(1-42) in anterior pituitary membranes. These results indicate that the two naturally observed C-terminal extensions of rat PHI variously affected peptide potency on 6 rat membrane preparations.     

Shape of the pelvis and posture of the hindlimbs inPlateosaurus

The pelvis ofPlateosaurus is examined from a biomechanical point of view. The shape of the acetabulum in particular is analysed in order to determine the range of possible directions of the forces exchanged between femur and pelvis. These forces must have been more or less confined to a sagittal plane. From a quasi-static analysis under consideration of the major hip muscles ofPlateosaurus, a nearly but not fully extended posture of the hindlimbs can be deduced. The hip joints ofPlateosaurus and probably of some other dinosaurs with a narrow biacetabular width were balanced rather by adducting than by abducting muscles.     

Population analysis in a denitrifying sand filter: conventional and in situ identification of Paracoccus spp. in methanol-fed biofilms.

The microbial community of a denitrifying sand filter in a municipal wastewater treatment plant was examined by conventional and molecular techniques to identify the bacteria actively involved in the removal of nitrate. In this system, denitrification is carried out as the last step of water treatment by biofilms growing on quartz grains with methanol as a supplemented carbon source. The biofilms are quite irregular, having a median thickness of 13 to 20 microns. Fatty acid analysis of 56 denitrifying isolates indicated the occurrence of Paracoccus spp. in the sand filter. 16S rRNA-targeted probes were designed for this genus and the species cluster Paracoccus denitrificans-Paracoccus versutus and tested for specificity by whole-cell hybridization. Stringency requirements for the probes were adjusted by use of a formamide concentration gradient to achieve complete discrimination of even highly similar target sequences. Whole-cell hybridization confirmed that members of the genus Paracoccus were abundant among the isolates. Twenty-seven of the 56 isolates hybridized with the genus-specific probes. In situ hybridization identified dense aggregates of paracocci in detached biofilms. Probes complementary to the type strains of P. denitrificans and P. versutus did not hybridize to cells in the biofilms, suggesting the presence of a new Paracoccus species in the sand filter. Analysis using confocal laser scanning microscopy detected spherical aggregates of morphologically identical cells exhibiting a uniform fluorescence. Cell quantification was performed after thorough disruption of the biofilms and filtration onto polycarbonate filters. An average of 3.5% of total cell counts corresponded to a Paracoccus sp., whereas in a parallel sand filter with no supplemented methanol, and no measurable denitrification, only very few paracocci (0.07% of cells stained with 4',6-diamidino-2-phenylindole) could be detected. Hyphomicrobium spp. constituted approximately 2% of all cells in the denitrifying unit and could not be detected in the regular sand filter. This clear link between in situ abundance and denitrification suggests an active participation of paracocci and hyphomicrobia in the process. Possible selective advantages favoring the paracocci in this habitat are discussed.     

Anchor-linked intermediates in peptide amide synthesis are caused by dimeric anchors on the solid supports

Cleavage and kinetic studies have been carried out using commercially obtained H-Tyr(tBu)-5-(4′-aminomethyl-3′,5′-dimethoxyphenoxy)valeric acid-TentaGelS (H-Tyr(tBu)-4-ADPV-TentaGelS) and H-Tyr (tBu)-4-ADPV-Ala-aminomethyl-resin (H-Tyr(tBu)-4-ADPV-AM-resin) prepared from commercially available resin and loaded with commercially available Fmoc-4-ADPV-OH amide anchor. Cleavage with pure trifluoroacetic acid (TFA) gave the intermediate H-Tyr-4-ADPV-NH₂, which was then degraded to H-Tyr-NH₂, and cleavage with TFA/dichloromethane (1:9) yielded H-Tyr-4-ADPV-NH₂ which could be isolated in preparative amounts. Cleavage reactions with ¹⁵N-labelled H-Ala-4-ADPV-[¹⁵N]-Gly-AM-resin yielded the intermediate H-Ala-4-ADPV-NH₂, which contained no ¹⁵N as demonstrated by ¹H-NMR. The analysis of the commercial Fmoc-4-ADPV-OH amide anchor showed the presence of Fmoc-4-ADPV-4-ADPV-OH as an impurity in high amounts. This dimeric anchor molecule is the cause of formation of the anchor-linked peptide intermediate obtained during the cleavage from the resin. The particularly high acid-lability of the amide bond between the two ADPV moieties was utilized to synthesize sidechain and C-terminally 4-ADPV protected pentagastrin on a double-anchor resin, and to cleave it using 5% trifluoroacetic acid in dichloromethane. This method may offer a new way for the synthesis of protected peptide amides with improved solubility to be used in fragment condensation.