Differential regulation of basic protein phosphorylation by calcium phospholipid and cyclic-AMP-dependent protein kinases

Myelin basic protein, an 80-kilodalton (kDa) protein in rat oligodendrocytes, and an 80-kDa basic protein in neuroblastoma x neonatal Chinese hamster brain explant hybrids were phosphorylated extensively when the cells were treated with either phorbol esters (TPA) or diacylglycerols (e.g., oleyoyl-acetylglycerol). TPA-stimulated phosphorylation was inhibited by pre-incubation with 50 microM psychosine (galactosyl-sphingosine), confirming that it is mediated through the phospholipid-dependent protein kinase C (PK-C). Surprisingly, phosphorylation of these proteins was inhibited by incubation of cells with agents which result in activation of cyclic-AMP-dependent protein kinase (dibutyryl cyclic AMP or forskolin). In contrast, phosphorylation of other nonbasic proteins, for example, the oligodendrocyte-specific 2',3'-cyclic nucleotide phosphohydrolase, was stimulated under these conditions (Vartanian et al.: Proceedings of the National Academy of Sciences of the United States of America 85:939, 1988). The possible role of cyclic AMP in activating specific phosphatases or restricting the availability of diacylglycerol for PK-C activation is discussed.     

Escherichia coli CAN lacks a tRNA-processing nuclease.

Escherichia coli strain CAN is unable to support the growth of bacteriophage T4 strains requiring the suppressor function of T4 tRNASer. Biochemical analysis of the mutant strain revealed that it is deficient in a RNase which acts on the artificial tRNA precursor tRNA-C-U.     

Hybridization selection of nucleic acid-protein complexes. 1. Detection of proteins cross-linked to specific mRNAs and DNA sequences by irradiation of intact Escherichia coli cells with ultraviolet light

A method is presented for the detection in crude lysates of subnanogram amounts of proteins covalently bound to a specific nucleic acid sequence. The sensitivity of this method enabled us to study proteins cross-linked to specific DNA and mRNA sequences by irradiation of intact Escherichia coli cells with ultraviolet light. Among the proteins cross-linked to pBR322 DNA, the single strand binding protein, the HU-proteins, and the RNA polymerase beta and sigma subunits were present. Some, but not all proteins were cross-linked to 5-bromodeoxyuridine-substituted DNA more efficiently than to normal DNA. Ribosomal protein S1 is by far the most prominent protein cross-linked to mRNAs. Among the proteins cross-linked in smaller amounts to mRNAs are translation initiation factor IF 1, and at least six proteins of the 30 S ribosomal subunit, among which is S21. No 50 S proteins, nor IF-2, IF-3 or any of the elongation factors could be detected. Some UV-induced nucleic acid-protein cross-links were found to be heat-labile. It is concluded that the method employed may be used to compare the proteins interacting with different mRNAs, as well as single-copy DNA sequences from bacteria and eucaryotes with low complexity genomes.     

Manifestations of angina morbidity as a reflection of the self-regulation of the epidemic process in streptococcal infection

The data on the application of the principles of the self regulation of the epidemic process for understanding the annual dynamics of angina morbidity in organized groups of adults are presented. In this case the reservation of group A streptococci occurs in chronic (resident) carriers, whose proportion was found to be 15.8 +/- 2.6%. The epidemic manifestations of morbidity are regulated mainly by the concentration of newly arrived members in the groups, i. e. by the size of the stratum providing the optimum conditions for the parasitization of the streptococcal population. The annual morbidity levels depend essentially not only on the heterogeneity of the group members with respect to their susceptibility to streptococcal infection, but also on the conditions of their accommodation, affecting the transmission of droplet infection. The role of individual risk factors in the variation of the quantitative characteristics of the angina morbidity manifestations under study is calculated.     

Management of the Wadden Sea

The Wadden Sea situated along the North Sea coasts of Denmark, the Federal Republic of Germany and The Netherlands represents one of the world's largest bar-built type of estuaries. The area is a typical sedimentation and mineralization basin, with a large influx of organic matter from the adjoining North Sea, consequently a delicate oxygen balance and a rich benthic macrofauna, poor in species, which serves as food for juveniles of some commercially important North Sea fishes and for large numbers of migrating and wintering waders and waterfowl. Past and present activities of the human society in the area include fisheries (mainly for shrimp and mussels, semi-culture), shipping, land reclamation, recreation, dredging for sand and shells, and waste discharge from industries and human communities. Until the present these activities, although sometimes conflicting, did not fundamentally affect the area and its biota (pollution excluded), but future claims, including the construction of large deep-sea harbours, drilling for natural gas and oil, large-scale land reclamation and increased industrialization etc., might gradually induce degradation. For instance, area reduction by continued land reclamation could lead to irreversible losses of specific biotopes (e. g. salt-marshes, mud-flats), which could affect the size of bird and fish populations in a much wider region. Increased pollution, which has already inflicted damage on bird and seal populations, could reduce the fauna and hence the value of the area as a natural sanctuary. In the event of a proposal for a new human activity in the area, the present standing practice in the countries concerned requires an evaluation of its safety and economic aspects and its environmental impact. However, the various plans are considered separately and there is a general need for integrated management of the area.     

Effects of serial anesthesia using ketamine or ketamine/medetomidine on hematology and serum biochemistry values in rhesus macaques (Macaca Mulatta)

Background  This study aimed at determining the cumulative effect of daily anesthesia, using two drug regimens, over hematological and biochemical parameters.
Methods  Blood samples were obtained from rhesus monkeys 20 minutes after intramuscular administration of ketamine or ketamine/medetomidine combination for three consecutive days and results were evaluated to determine their effect on hematological and serum biochemistry values. Statistical significance of drug, day, and interaction of these two variables were evaluated.
Results  Drug effect resulted in a dramatic increase of aspartate aminotransferase and creatine kinase values. Day effect resulted in decreases of RBC, HCT, Hgb, and alkaline phosphatase but an increase of other biochemical parameters evaluated. The drug/day interaction effect was found to be –significant for RBC, platelets, aspartate aminotransferase, alanine aminotransferase, and creatine kinase values.
Conclusion  The results of our study suggest a cumulative effect of serial anesthesia and should be an important consideration when interpreting hematology and serum biochemistry in rhesus macaques.     

Antibody-targeted photolysis: in vitro immunological, photophysical, and cytotoxic properties of monoclonal antibody-dextran-Sn(IV) chlorin e6 immunoconjugates.

A set of anti-melanoma immunoconjugates were prepared which contained chlorin e6: antibody molar ratios of 18.9:1, 11.2:1, 6.8:1, and 1.7:1. All immunoconjugates retained antigen binding activity regardless of the chromophore:antibody substitution ratio that was attained. In contrast, the ground-state absorption spectra of the immunoconjugates showed features which appeared to be dependent on the chromophore:antibody molar ratio. In addition, the quantum yield of singlet oxygen generated by the conjugated chromophores was observed to be significantly less than that observed with the unbound dye. Time-resolved absorbance spectroscopy of the chromophore excited triplet state indicated that the loss of singlet oxygen quantum yield resulted from diminished chromophore triplet yield. Analysis of data obtained from in vitro photolysis of target melanoma cells, in combination with that obtained from the immunochemical and photochemical studies, indicates that the observed immunoconjugate phototoxicity can be reasonably quantitatively represented by (1) the ability of the immunoconjugate to bind SK-MEL-2 cell surface antigen, (2) the amount of chromophore localized at the target cells by immunoconjugate binding, (3) the delivered dose of light at 634 nm, and (4) the singlet oxygen quantum yield of the antibody-bound photosensitizer. Though these data argue strongly for photolysis by the cumulative dosage of singlet oxygen at the cell membrane, nonetheless, the concurrent photoinduced release of other cytotoxic agents should not be ruled out.     

Sex difference in maximal oxygen uptake. Effect of equating haemoglobin concentration

Ten men and 11 women were studied to determine the effect of experimentally equating haemoglobin concentration ([Hb]) on the sex difference in maximal oxygen uptake (VO2max). VO2max was measured on a cycle ergometer using a continuous, load-incremented protocol. The men were studied under two conditions: 1) with normal [Hb] (153 g X L-1) and 2) two days following withdrawal of blood, which reduced their mean [Hb] to exactly equal the mean of the women (134 g X L-1). Prior to blood withdrawal, VO2max expressed in L X min-1 and relative to body weight and ride time on the cycle ergometer test were greater (p less than .01) in men by 1.11 L X min-1 (47%), 4.8 ml X kg-1 min-1 (11.5%) and 5.9 min (67%), respectively, whereas VO2max expressed relative to fat-free weight (FFW) was not significantly different. Equalizing [Hb] reduced (p less than .01) the mean VO2max of the men by 0.26 L X min-1 (7.5%), 3.2 ml X kg-1 min-1 (6.9%) or 4.1 ml X kg FFW-1 min-1 (7.7%), and ride time by 0.7 min (4.8%). Equalizing [Hb] reduced the sex difference for VO2max less than predicted from proportional changes in the oxygen content of the arterial blood and arteriovenous oxygen content difference during maximal exercise. It was concluded that the sex difference in [Hb] accounts for a significant, but relatively small portion of the sex difference in VO2max (L X min-1). Other factors such as the dimensions of the oxygen transport system and musculature are of greater importance.     

Interaction of hydrophobic bis (D-mannose) derivatives with adipocyte and erythrocyte sugar transport systems

The inhibition of sugar uptake by a series of hydrophobic bis(D-mannose) derivatives has been measured in rat adipocytes. When the D-mannose moieties of the bis compounds are separated by a hexane bridge the transport inhibition constant (Ki) is greater than for a decane-bridged molecule. This is probably due to the increased hydrophobicity of the bridge of the decane-bridged compound. The enhancement in affinity due to the second sugar in the bis(D-mannose) derivatives is probably only 2-fold, since half reduction of the bis(D-mannosyloxy)hexane increases Ki approx. 2-3-fold. N'-DNP-1,3-bis(D-mannos-4'-yloxy)propyl-2-amine has very high affinity in insulin-treated cells. The affinity is approx. 1000-fold higher than for D-mannose. This enhancement is probably due to the hydrophobicity of the DNP group. The distance from the sugar to the hydrophobic group is important because an increase in Ki occurs if an aminocaproyl spacer is introduced between the DNP group and 1,3-bis(D-mannos-4'-yloxy)propyl-2-amine. Aminocaproyl and glycyl spacers also increase the Ki for NAP derivatives of 1,3-bis(D-mannos-4'-yloxy)propyl-2-amine. Each of the hydrophobic bis(D-mannose) derivatives has a lower Ki in insulin-treated cells. This may be due to an insulin responsive hydrophobic interaction between the hydrophobic portion of the sugar and a hydrophobic domain in the transport system. The inhibition constants for the hydrophobic bis(D-mannose) compounds have also been measured in human erythrocytes.