Calcitonin—C.N.S. action to control the pattern of intestinal motility in rats

Synthetic calcitonin injected into the lateral ventricles (ICV) of rats at picomolar concentration restores the “fasted” motility pattern of the small intestine in fed rats at doses as low as 0.083 picomoles. This effect which appeared in less than 5 min and persisted at least 2 hours for 0.83 picomole, was blocked by a previous intraventricular administration of 10 μg of calcium gluconate. At 0.83 picomole ICV, calcitonin also suppressed the disruption of the “fasted” pattern induced by intravenous infusion of Pentagastrin (6 μg·kg^?1·h^?1) but not that induced by insulin (0.5 U·kg^?1). These findings support the hypothesis that calcitonin acts centrally to control the pattern of intestinal motility by inhibiting the digestive influences responsible for the “fed” pattern. All of these peripheral influences are mediated by a Ca⁺⁺ sensitive central structure.     

Inertial shear forces and the use of centrifuges in gravity research. What is the proper control?

Centrifuges are used for 1 x g controls in space flight microgravity experiments and in ground based research. Using centrifugation as a tool to generate an Earth like acceleration introduces unwanted inertial shear forces to the sample. Depending on the centrifuge and the geometry of the experiment hardware used these shear forces contribute significantly to the total force acting on the cells or tissues. The inertial shear force artifact should be dealt with for future experiment hardware development for Shuttle and the International Space Station (ISS) as well as for the interpretation of previous space-flight and on-ground research data.     

No role of the 5′ untranslated region of ornithine decarboxylase mRNA in the feedback control of the enzyme

The polyamines are ubiquitous in nature and appear to fulfil several important functions, mostly related to growth, in the cell. The first, and often rate-limiting, step in the biosynthesis of the polyamines is catalysed by ornithine decarboxylase (ODC), which is subject to a variety of control mechanisms. The polyamines exert a strong feedback regulation of the expression - as well as the degradation of the enzyme. The regulation of ODC expression appears to occur at the translational level. The ODC mRNA contains a long GC-rich 5 untranslated region (UTR), which has been demonstrated to hamper the translation of the mRNA. However, it has not yet been conclusively established whether this part of the mRNA fulfils any function in relation to the polyamine-mediated control of ODC synthesis. In the present study, we have used stable transgenic CHO cells, expressing either full-length ODC mRNA or 5 UTR-truncated ODC mRNA, to elucidate the role, if any, of the 5 UTR in the translational regulation of the enzyme by polyamines. No differences in regulatory properties were observed between the cells expressing the full-length ODC mRNA and those expressing the ODC mRNA devoid of most the 5 UTR. The cell lines down-regulated ODC (synthesis as well as activity) to the same extent upon exposure to an excess of polyamines, demonstrating that the feedback control of ODC mRNA translation occurs by a mechanism independent of the major part of the 5 UTR of the ODC mRNA.     

Immunogenetic study on the polymorphism of serum α2-lipoproteins in mink. I. Identification and genetic control of five Lpm allotypes

Five allotypes, Lpm 1, Lpm 2, Lpm 3, Lpm 4, and Lpm 5, were detected by isoimmunization in mink sera. Immunoelectrophoresis, preparative ultracentrifugation, and histochemical tests for lipids and esterase permitted reference of these alloantigenic markers to a very high density ₂-lipoprotein. Based on population analysis and breeding tests, five genetic units are postulated: Lpm ¹, Lpm⁴, Lpm^3,4, Lpm^1,2, and Lpm ^2,4,5. These units determine the polymorphism of the Lpm system and behave as Mendelian alleles.     

β-adrenergic control of the water permeability of the skin during rehydration in the toad Bufo arenarum

1. Toads dehydrated to 80% of their standard weight (% SW) were rehydrated during 3 hr in distilled water.2. Water permeability of the skin was positively correlated with the degree of dehydration in the range 80–100% SW.3. Systemic administration of the β-adrenergic agonist isoproterenol (5 mg/kg) 90 min after rehydration started (animals fully hydrated) increased skin permeability to the values observed in 80% SW dehydrated animals.4. The administration of the β-adrenergic blocker propranolol (5 mg/kg) 15 min before rehydration started produced a long-lasting decrease in water permeability during the 3 hr of rehydration.5. The results are consistent with the hypothesis of a β-adrenergic control of the water permeability of the skin during rehydration.     

Immunogenetic study on the polymorphism of serum α2-lipoproteins in mink. II. Identification of allotypes Lpm-7 and Lpm-8 and genetic control of seven markers of the Lpm system

By means of alloimmunization of mink, two new antigens, Lpm-7 and Lpm-8, were detected in their sera. Lpm-7 and Lpm-8 allospecificities were referred to a very high density ₂-lipoprotein (Lpm) by the following criteria: histochemical tests, immunoelectrophoresis, preparative ultracentrifugation, and coalescence of alloprecipitates with heteroprecipitates in double diffusion tests. Genetic analysis indicated that Lpm-7 and Lpm-8, together with the earlier described Lpm-1, Lpm-2, Lpm-3, Lpm-4, and Lpm-5, share a common immunogenetic system. Polymorphism for the seven markers is conditioned by the genetic units Lpm ⁸, Lpm ⁴, Lpm ^{4, 8}, Lpm ^{4, 7}, Lpm ^{3, 4, 8}, Lpm ^{1, 8}, Lpm ^{1, 2, 7}, and Lpm ^{2, 4, 5, 7}, which behave as alleles. Of these units, the latter six are probably haploid sets of closely linked genes.     

The stimulus-secretion coupling of glucose-induced insulin release. Does glycolysis control calcium transport in the B-cell?

1. The metabolism of glucose and the exchangeable Ca2+ pool were measured in rat pancreatic islets, in order to assess the possible significance of glycolysis in the process of glucose-induced insulin release. 2. At high glucose concentration (16.7 mM), glucose was metabolized at the following rate (pmol of glucose residue/h per islet +/- S.E.M.): 131 +/- 11 for glucose uptake, 129+/-8 for glucose utilization, as judged by the conversion of [5-3H]glucose into 3H2O,60+/-2 for lactate output and 25+/-2 for glucose oxidation. 3. The secretory pattern usually correlated with the metabolic data. For instance, the ability of different sugars (glucose, mannose, fructose, galactose, D-glyceraldehyde) to stimulate lactate output closely paralleled their relative insulinotropic capacity. A disparity between metabolic and secretory responses was, however, encountered in the presence of dibutyryl cyclic AMP and theophylline. 4. Despite this contrasting behaviour, the size of the Ca2+- exchangeable pool (net uptake of 45Ca2+) was invariably proportional to the rate of lactate output under all experimental conditions examined. It is concluded that glycolysis usually exerts a tight control on the rate constant for Ca2+ transport across the B-cell membrane.     

The Italian experience in the control of rabies. III. Laboratory studies on SADB19 Tü vaccine used in the fox vaccination campaign

Results of laboratory investigations on the SADB19 Tü vaccine used for oral vaccination of fox show: 1) the need to check the vaccine efficacy before its application in the field; 2) the importance of monoclonal antibodies to distinguish sylvatic from vaccinal virus strains in the diagnosis of rabies during the vaccination campaigns; 3) the relevance of a careful evaluation of the epidemiological risk encountered when releasing baits containing activated vaccine.     

Functional role of the charge at the T538 residue in the control of protein kinase Cθ

We show that protein kinase C (PKC) θ localized at the Golgi complex is partially conjugated to monoubiquitin. Using the inactive T538A and activable T538E mutants of PKCθ, we demonstrate that the presence of an uncharged residue at the 538 position of the activation loop favors both association with the Golgi and monoubiquitination of the kinase. Moreover, the inactive PKCθ does not translocate from the Golgi in response to a short-term cell stimulation with a phorbol ester and is subjected to different proteolytic degradation pathways compared to the activable cytosolic kinase. These findings highlight the role of T538 as a critical determinant to address the activable and the inactive PKCθ molecules to different intracellular compartments and to specific post-transductional modifications. The functional relevance of these observations is supported by the impaired cell division observed in phenotypes expressing high levels of the inactive PKCθ.     

We appreciate the invaluable contributions of the following reviewers during the editing of Vol. 8 Nos. 1–2.

Acknowledgments

We appreciate the invaluable contributions of the following reviewers during the editing of Vol. 8 Nos. 1–2.     

Excitation energy transfer in aggregates of Photosystem I and Photosystem II of the cyanobacterium Synechocystis sp. PCC 6803: Can assembly of the pigment-protein complexes control the extent of spillover?

The fluorescence profile of Photosystem I/Photosystem II mixtures in different solvent systems shows that both non-hydrophobic and hydrophobic interactions govern their association and control energy transfer from Photosystem II to Photosystem I. The non-hydrophobic interactions lead to a highly efficient excitation energy transfer from Photosystem II to Photosystem I. In view of this, we propose that similar non-hydrophobic interactions, between the Photosystem II and Photosystem I peripheral proteins, also play a significant role in their association in thylakoids that control state transitions in cyanobacteria. This revised version was published online in June 2006 with corrections to the Cover Date.     

How can immunology contribute to the control of tuberculosis?

Tuberculosis poses a significant threat to mankind. Multidrug-resistant strains are on the rise, and Mycobacterium tuberculosis infection is often associated with human immunodeficiency virus infection. Satisfactory control of tuberculosis can only be achieved using a highly efficacious vaccine. Tuberculosis is particularly challenging for the immune system. The intracellular location of the pathogen shields it from antibodies, and a variety of T-cell subpopulations must be activated to challenge the bacterium's resistance to antibacterial defence mechanisms. A clear understanding of the immune responses that control the pathogen will be important for achieving optimal immunity, and information provided by functional genome analysis of M. tuberculosis will be vital in the design of a future vaccine.