Dopamine β-monooxygenase: Reduced enzyme needs additional reductant for completion of the catalytic cycle

The enzyme-bound copper of dopamine $\text{β}\text{-monooxygenase}$ was reduced by ascorbate and the enzyme separated from excess reductant by gel filtration. The reduced enzyme did not hydroxylate substrate at a rate consistent with the turnover time. This observation supports a sequential mechanism.     

Mapping of the Gene Encoding the Regulatory Subunit RIIα of cAMP-Dependent Protein Kinase (Locus PRKAR2A) to Human Chromosome Region 3p21.3–p21.2

We have determined the chromosomal localization of the gene for the regulatory subunit RIIα of cAMP-dependent protein kinase (locus PRKAR2A) to human chromosome 3 using polymerase chain reaction (PCR) and Southern blot analysis of two different somatic cell hybrid mapping panels. Furthermore, PCR analysis of a chromosome 3 mapping panel revealed the presence of a human RIIα-specific amplification product only in cell lines containing the region 3p21.3–p21.2. The localization of PRKAR2A was confirmed by PCR mapping using the Stanford G3 Radiation Hybrid Panel as template. The results from this analysis demonstrated that PRKAR2A is most closely linked to D3S3334 (lod score 12.5) and flanked by D3S1322E and D3S1581.     

Role of Cx43 Phosphorylation and MAP Kinase Activation in EGF Induced Enhancement of Cell Communication in Human Kidney Epithelial Cells

Epidermal growth factor (EGF) has been found to induce enhanced gap junctional intercellular communication (GJIC) in the human kidney epithelial cell line K7. This is in contrast to what is reported for other cell types, which all show decreased GJIC in response to EGF. In the present study it is shown that 12-O-tetradecanoylphorbol-13-acetate (TPA) and EGF induce similar phosphorylation pattern of the gap junction protein connexin43 (Cx43) in K7 cells, although their effects on GJIC are opposite. Tyrosine phosphorylation of a 42 kD protein was observed to be induced concomitantly with phosphorylation of Cx43. EGF was however found to induce only serine phosphorylation of Cx43, indicating that the tyrosine kinase activity of the EGF receptor was not directly affecting the gap junction protein. The 42 kD protein phosphorylated on tyrosine was identified to be a mitogen activated protein (MAP) kinase. Both EGF and TPA was found to activate MAP kinase in these cells. Phosphorylation of Cx43 and enhancement of GJIC in response to EGF occurred with difference in time course. Phosphorylation of Cx43 was completed within 15 min, while the enhanced GJIC appeared 2-3 h later. It is therefore possible that regulation of synthesis or transport of Cx43 is responsible for the increase in GJIC, rather than direct involvement of Cx43 phosphorylation. This is in support of our previous finding that protein synthesis is necessary for EGF induced upregulation of GJIC in K7 cells.     

Isolation of self antigen-reactive cells from inflamed islets of nonobese diabetic mice using CD4high expression as a marker.

The low precursor frequency of Ag-reactive CD4+ T cells has been a barrier to the study of CD4+ T cell responses to conventional Ags as well as CD4+ T cell responses to autoantigens recognized during the course of an autoimmune disease. We have recently reported that all "conventional Ag" reactive CD4+ T cells are contained within the subpopulation expressing high levels of the CD4 molecule, termed CD4high. We have identified a CD4high population in the islets of Langerhans of prediabetic nonobese diabetic (NOD) mice that is extremely potent in transferring disease. As few as 500 CD4high islet-infiltrating CD4+ T cells transferred insulin-dependent diabetes mellitus to CD8 reconstituted NOD-SCID mice within 30 days of transfer. In contrast, CD4high T cells isolated from either NOD spleen or salivary glands did not transfer insulin-dependent diabetes mellitus into similar CD8-reconstituted NOD-SCID recipients. These data indicate that the precursor frequency of NOD islet-reactive, pathogenic CD4+ T cells is much higher in the prediabetic NOD pancreas than in these other organs. The islet-infiltrating CD4high T cells displayed selected memory markers, by cell surface analysis, and displayed a Th 1 phenotype by RNase protection assay, but had a marked decrease in IL-4 mRNA determined by quantitative real time PCR when compared with the less pathogenic CD4normal islet-infiltrating T cells. Use of the CD4high marker to select Ag activated T cells represents a tool to isolate and study pathogenic CD4+ T cells from autoimmune lesions in which the Ag has not been previously defined.     

DIET OF WEANED PUPS AND SEASONAL VARIATIONS IN BODY CONDITION OF JUVENILE BARENTS SEA HARP SEALS PHOCA GROENLANDICA

Data on blubber depth, body condition, and diet were collected from young of year and juvenile harp seals ( Phoca groenlandica ) in the Barents Sea in the periods February-April and June-October 1990–1997. Harp seal pups feed independently shortly after weaning. In the southern parts of the Barents Sea the diet of harp seal pups consisted mainly of euphausiids ("krill") Thysanoessa sp. and amphipods of the genus Parathemisto . The change in body condition of harp seal pups between weaning (mid-March) and June indicated that considerable amounts of blubber energy, deposited during suckling, were mobilized. This suggests that the early food intake of weaned pups was insufficient to meet the energy requirements. The pattern of low spring and earlysummer body condition, followed by a subsequent rapid improvement in condition during late summer and autumn appeared to occur not only among pups-of-the-year, but also in one- and two-year old harp seals.     

MORPHOMETRIC COMPARISON OF MINKE WHALES BALAENOPTERA ACUTOROSTRATA FROM DIFFERENT AREAS OF THE NORTH ATLANTIC

Multivariate statistical analyses of 18 morphometric characters were performed in order to evaluate potential heterogeneity between predefined minke whale stock unit areas in the North Atlantic (West Greenland, Central, and Northeastern stocks). Results from principal component analyses suggested that the data cannot be regarded as random samples drawn from one uniform distribution. The overlap between groups was too substantial, however, to allow a firm conclusion concerning the question of isolated breeding stocks versus a large common breeding pool.     

Morphological transformation and catalase activity of syrian hamster embryo cells treated with hepatic peroxisome proliferators,TPA and nickel sulphate

The abilities of the hepatic peroxisome proliferators (HPPs) clofibrate, di(2-ethylhexyl)phthalate (DEHP), mono(2-ethylhexyl)- phthalate (MEHP), 2,4-dichlorophenoxy acetic acid (2,4-D), 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) and tiadenol to induce morphological transformation and to increase the catalase activity of Syrian hamster embryo (SHE) cells were studied. DEHP, MEHP, clofibrate and tiadenol induced morphological transformation of SHE cells and increased the catalase activity. DEHP was more potent than clofibrate and tiadenol in both inducing catalase and morphological transformation, while MEHP seemed more potent than DEHP in inducing catalase, but not morphological transformation, 2,4,5-T and 2,4-D did not induce morphological transformation, but 2,4,5-T was more potent than clofibrate in increasing the catalase activity. These results show that several HPPs induce morphological transformation of SHE cells and an increase in the catalase activity. There is, however, no direct connection between these two parameters, as seen from the results of 2,4,5-T. The tumor promoter TPA, and the metal salt nickel sulphate, induced morphological transformation of SHE cells without any appreciable increase in the catalase activity. These results further corroborate the dissociation between induction of morphological transformation and the increase in catalase activity.Abbreviations Clofibrate ethyl-2-(p-chlorophenox) isobutyrate - 2,4-D 2,4-dichlorophenoxy acetic acid - DEHP di(2-ethylhexyl)phthalate - HPP hepatic peroxisome proliferator - MEHP mono(2-ethylhexyl)phthalate - SHE Syrian hamster embryo - 2,4,5-T 2,4,5-trichlorophenoxy acetic acid - tiadenol di(hydroxyethylthio)-1,10-decane     

Manipulations of male parental investment in polygynous pied flycatchers, Ficedula hypoleuca

We designed three experiments to identify important cues asto how bigamous male pied flycatchers (Ficedula hypoleuca) apportionnestling feeding between their broods. Normally, males givepriority to their primary brood, that is, the brood of theirfirst-acquired mate. In the first experiment, we reversed thehatching order of primary and secondary broods by substitutingeggs. Males responded by reallocating their efforts in favorof secondary broods. Males thus favored the brood that hatchedfirst, irrespective of female mating order. In the second experiment,carried out on the same males when the younger brood was 4 or5 days old, we transferred the older brood to the nest of theyounger, and vice versa; the males changed their investmentpattern accordingly, still giving priority to the older brood.In the third experiment, primary and secondary broods were madeto hatch on the same day. In these cases, males divided theirnestling feeding efforts fairly equally between the broods.The results reveal a remarkable flexibility of male investmentdecisions, which is discussed in light of parental investmenttheory. The fact that the degree of male assistance to secondarymates is variable and that it is to a large extent predictablefrom the nest initiation asynchrony of the two females has importantimplications for our understanding of the polyterritorial matingsystem of this species.     

Forest types of northern Sweden

An Appalachian-oak forest in a small montane watershed was sampled to calibrate and test an existing forest dynamics simulation model. Indices developed in earlier studies by Whittaker were used to estimate the response of different tree species to soil moisture. As is the case in many forest modeling applications, neither detailed environmental data at a micro-spatial scale nor quantitative historical stand data were available for the study.A protocol of both model parameter estimation and simulation output evaluation is developed. The method involves simulation experiments under which the model parameters are allowed to vary systematically with respect to environmental control variables, allowing one to generate a field of potential simulation results that can be searched for patterns shared by the observed data. The degree to which common patterns emerge provides a measure of model sensitivity to patterns at the scale of interest. This protocol can provide an appraisal of the appropriateness of a simulation model to the system of interest and can be used to assess the performance of the model in future applications. Nomenclature: Little, E.B. 1971. Atlas of United States trees. Government Printing Office, Washington, D.C.     

Early evolution of histone mRNA 3' end processing

The replication-dependent histone mRNAs in metazoa are not polyadenylated, in contrast to the bulk of mRNA. Instead, they contain an RNA stem-loop (SL) structure close to the 3' end of the mature RNA, and this 3' end is generated by cleavage using a machinery involving the U7 snRNP and protein factors such as the stem-loop binding protein (SLBP). This machinery of 3' end processing is related to that of polyadenylation as protein components are shared between the systems. It is commonly believed that histone 3' end processing is restricted to metazoa and green algae. In contrast, polyadenylation is ubiquitous in Eukarya. However, using computational approaches, we have now identified components of histone 3' end processing in a number of protozoa. Thus, the histone mRNA stem-loop structure as well as the SLBP protein are present in many different protozoa, including Dictyostelium, alveolates, Trypanosoma, and Trichomonas. These results show that the histone 3' end processing machinery is more ancient than previously anticipated and can be traced to the root of the eukaryotic phylogenetic tree. We also identified histone mRNAs from both metazoa and protozoa that are polyadenylated but also contain the signals characteristic of histone 3' end processing. These results provide further evidence that some histone genes are regulated at the level of 3' end processing to produce either polyadenylated RNAs or RNAs with the 3' end characteristic of replication-dependent histone mRNAs.