Metal thiolate coordination in the E7 proteins of human papilloma virus 16 and cottontail rabbit papilloma virus as expressed in Escherichia coli.

The oncogenic E7 proteins of human papilloma virus (HPV 16) and of cottontail rabbit papilloma virus (CRPV) have been purified from an expression system in Escherichia coli. The proteins as purified from E. coli contain one tightly bound Zn(II) ion per molecule. The metal site shows facile exchange with either Cd(II) or Cu(I). The HPV 16 E7 maximally bound one Cd(II) or two Cu(I) ions, while the CRPV E7 bound two Cd(II) or three Cu(I) ions. The Cd(II) and Cu(I) E7 molecules exhibited optical transitions in the ultraviolet suggestive of metal:thiolate coordination. E7 proteins from HPV 16 and CRPV contain 7 and 8 cysteines/molecule, respectively. Reaction of the E7 proteins with the sulfhydryl reagent, dithiodipyridine, revealed that all the cysteinyl sulfurs are present in the reduced thiol state. Cu(I)-E7 molecules are luminescent with maximal emission at 570 nm. The observed emission at room temperature is indicative of metal coordination within a compact protein environment shielded from solvent interactions. The emission maxima occurs at the same wavelength (570 nm) as Cu(I)-cysteinyl sulfur clusters in Cu(I)-metallothioneins. The single Zn(II) atom in each protein can be removed from E7 in the presence of EDTA. The resulting apoE7 molecules remain soluble and can be partially reconstituted with Cd(II) to regain the ultraviolet charge transfer transitions.     

The amino acid sequence of a major protein component in the light harvesting complex of the green photosynthetic bacterium Chlorobium limicola f. thiosulfatophilum

A 7.5-kDa protein has been isolated from chlorosomes of Chlorobium limicola f. thiosulfatophilum and the complete primary structure determined by a combination of automatic Edman degradation and plasma desorption mass spectrometry. The 74-residue protein shows great homology to a similar protein of unknown function which has been isolated from Pelodictyon luteolum but otherwise no significant homology to other proteins can be found. The possible role of the protein in the structure and function of the chlorosome is discussed.     

A controlled study of eight months of physical training and reduction of blood pressure in children: the Odense schoolchild study.

OBJECTIVE--To examine the effect of physical training on physical fitness and blood pressure in children aged 9-11 years. DESIGN--Prospective randomised controlled intervention study of a sample of children drawn from a population survey of coronary risk factors in children. SETTING--Odense, Denmark. SUBJECTS--69 children with mean blood pressure greater than or equal to 95th centile (hypertensive group) and 68 with mean blood pressure less than 95th centile (normotensive group), randomly selected from a population of 1369 children. INTERVENTION--67 children were randomised to receive three extra lessons a week of an ordinary school physical education programme for eight months. MAIN OUTCOME MEASURES--Physical fitness assessed by calculation of maximum oxygen uptake and blood pressure recorded by one unblinded observer. RESULTS--After three months neither blood pressure nor physical fitness had changed significantly. After adjustment for values in weight, height, heart rate, and the variable in question before training physical fitness rose significantly at the end of eight months'' training, by 3.7 mlO2/kg/min (95% confidence interval 2.2 to 5.3) in the normotensive training subgroup and by 2.1 mlO2/kg/min (0.1 to 4.2) in the hypertensive training subgroup compared with that in the controls. Systolic and diastolic blood pressures in the training subgroups fell significantly by 6.5 mm Hg (3.2 to 9.9) and 4.1 mm Hg (1.7 to 6.6) respectively in the normotensive group and by 4.9 mm Hg (0.7 to 9.2) and 3.8 mm Hg (0.9 to 6.6) respectively in the hypertensive group. CONCLUSIONS--Physical training lowers blood pressure and improves physical fitness in children and might have implications for an important non-pharmacological approach to primary prevention of essential hypertension.     

Incidence of chromosome abnormalities in newborn children. Comparison between incidences in 1969–1974 and 1980–1982 in the same area

Summary As part of an ongoing study of the influence of environmental factors on pregnancy, childbirth, and fetuses, comparisons have been made between incidences in 1969–1974 and in 1980–1982 of chromosome aberrations in liverborn children in the same area of Denmark. The incidence of chromosome aberrations in the first period was 2.6 per 1000, compared with 4.1 per 1000 during the latter period. However, the difference was mainly due to an increase in inversions, and this in turn was due to a difference in chromosome staining methods between the two periods.It is concluded that the Danish study and similar studies in the United States, Canada, and Scotland indicate that early detection of chromosome aberrations by chromosome examination at birth is indicated in order to be able to inform and counsel parents of children with chromosome aberrations. Chromosome examination at birth is also of importance in the diagnosis of structural inheritable chromosome aberrations and consequent family investigation and genetic counseling.     

Rats chronically injected with urine from Huntington's chorea patients do not striatal damage

Rats were injected subcutaneously for 147 consecutive days with large volumes of urine from control subjects and from patients with Huntington's chorea (HC) in an effort to test for presence of a possible neurotoxic substance in HC. No evidence of illness was observed in animals treated with HC urine, and their behavior did not differ from animals treated with control urine. After rats were sacrificed, striatum was examined for the biochemical and neuropathological changes seen in human striatum in HC. No deficiency of γ-aminobutyric acid content, nor reduction in activities of glutamic acid decarboxylase and choline acetyltransferase, was found in striatum of rats chronically treated with HC urine. Also, no significant differences were found between striatum of control and experimental rats by light or electron microscopy. These results neither support for exclude the possibility of a neurotoxic mechanism for the neuronal loss characteristic of HC.     

Phosphorylation of lens membrane: identification of the catalytic subunit of Na+, K+-ATPase

Receptor mediated endocytosis appears to depend on the action of a transglutaminase (TGase). Endocytosis can be induced in intact human RBC by the action of several classes of drugs. We tested the hypothesis that drugs acted by stimulating TGase activity. Of the endocytosis inducing drugs tested, neither primaquine nor vinblastine nor chlorpromazine enhanced TGase activity. We next tested the hypothesis that TGase activity was required for drug endocytosis in RBC by adding known TGase inhibitors. Paradoxically, m-Dansyl cadaverine, the most potent TGase inhibitor, produces endocytosis in human RBC. Therefore despite apparent striking morphologic similarities, drug induced endocytosis in RBC appears to proceed via different mechanisms from those involved in receptor mediated endocytosis in other cells.In the receptor-mediated endocytosis of some hormones and growth factors, it appears that the receptor-ligand complex forms clusters over clathrin coated pits which are then internalized as endocytic vacuoles. Both the clustering and internalization of ligands are inhibited by a variety of agents shown to inhibit transglutaminase (TGase) and it is therefore proposed that TGase participates in receptor-mediated endocytosis (1–3). Human erythrocytes undergo endocytosis when exposed to drugs like primaquine, chlorpromazine, and vinblastine (4), all of which are amphipathic cations (4). However, the mechanism of drug action is not known nor is it clear that this is a form of receptor-mediated endocytosis (4). Furthermore, clustering of receptors can occur in neonatal but not adult human RBC (5). TGase has been measured in human red cells (6) although its physiologic role is unknown. Like all TGases, it is calcium dependent (6,7), and primaquine induced red cell endocytosis is enhanced by Ca⁺⁺ addition (8). Therefore, we tested the hypothesis that TGase participates in drug induced endocytosis in intact human red cells.     

Studies on the origin of the near-infrared (800–900 nm) absorption of cytochrome c oxidase

Data are presented which were collected in the course of the past ten years and bear on the correlation of absorbance at 800 nm and the EPR signal at g = 2 (‘copper signal’) of cytochrome c oxidase in various states of oxidation and ligation. Both EPR and optical reflectance spectra were obtained at low temperature (?170 to ?190°C). For some sets of samples spectra were recorded in the range 500–1100 nm. A particular effort was made to study this correlation with what are called ‘mixed valence’ states (Greenwood, C., Wilson, M.T. and Brunori, M. (1974) Biochem. J. 137, 205–215), when cytochrome a and the EPR-detectable copper are thought to be oxidized and the other components reduced and vice versa. These data show no evidence that the copper component of cytochrome oxidase which has so far not been detected by EPR makes a contribution to the absorption between 800 and 900 nm exceeding 10–15% of the total, which is close to or within the error of the respective measurements. For the various states of the oxidase examined in this work the 700–800 nm region did not appear to be more useful than the 800–900 nm region for determining the state of the EPR-undetectable copper in a reliable way. These conclusions are in agreement with results presented previously from other laboratories concerning the relationship of optical (approx. 800 nm) and EPR spectroscopic (g = 2) data obtained with the enzyme.     

A routine method for quantitative determination of soluble carbohydrates in small samples of plant material with gas-liquid chromatography

Aluminium in human tissue samples has been determined by atomic absorption spectrophotometry using the nitrous oxide-acetylene flame and the graphite furnace atomizer. The two methods are compared. Flameless atomic absorption was found superior when standard addition was applied. A routine method is thus described in detail in which aluminium levels down to 0.1 mg/kg of freeze-dried tissue and 0.01 mg/liter of serum can be determined.