Constitutively Elevated Blood Serotonin Is Associated with Bone Loss and Type 2 Diabetes in Rats

Reduced peripheral serotonin (5HT) in mice lacking tryptophan hydroxylase (TPH1), the rate limiting enzyme for 5HT synthesis, was reported to be anabolic to the skeleton. However, in other studies TPH1 deletion either had no bone effect or an age dependent inhibition of osteoclastic bone resorption. The role of 5HT in bone therefore remains poorly understood. To address this issue, we used selective breeding to create rat sublines with constitutively high (high-5HT) and low (low-5HT) platelet 5HT level (PSL) and platelet 5HT uptake (PSU). High-5HT rats had decreased bone volume due to increased bone turnover characterized by increased bone formation and mineral apposition rate, increased osteoclast number and serum C-telopeptide level. Daily oral administration of the TPH1 inhibitor (LX1032) for 6 weeks reduced PSL and increased the trabecular bone volume and trabecular number of the spine and femur in high-5HT rats. High-5HT animals also developed a type 2 diabetes (T2D) phenotype with increased: plasma insulin, glucose, hemoglobin A1c, body weight, visceral fat, β-cell pancreatic islets size, serum cholesterol, and decreased muscle strength. Serum calcium accretion mediated by parathyroid hormone slightly increased, whereas treatment with 1,25(OH)₂D₃ decreased PSL. Insulin reduction was paralleled by a drop in PSL in high-5HT rats. In vitro, insulin and 5HT synergistically up-regulated osteoblast differentiation isolated from high-5HT rats, whereas TPH1 inhibition decreased the number of bone marrow-derived osteoclasts. These results suggest that constitutively elevated PSL is associated with bone loss and T2D via a homeostatic interplay between the peripheral 5HT, bone and insulin.     

Study of the carbohydrate part of yeast acid phosphatase

It has been found that the carbohydrate part of acid phosphatase from yeast Saccharomyces cerevisiae consists of 16 N-glycosidically linked carbohydrate chains containing from 14 to about 150 mannose units. The presence of very small amounts of O-glycosidically linked chains was indicated. Acetolysis studies pointed to a high similarity in the structure of acid phosphatase and mannan carbohydrate chains. A new method is described for cross-linking of acid phosphatase specifically via carbohydrate chains. The possibility to cross-link the enzyme subunits intramolecularly is in accordance with the suggestion that carbohydrate chains play a role in subunit associations.     

Physicians' strike and general mortality: Croatia's experience of 2003

The aim of the study was to establish whether the physicians' strike, which took place in Croatia in 2003, had an impact on the mortality of the population. Mortality data from the National Bureau of Statistics relating to the strike period (15 January - 14 February 2003) were selected and compared with the previous and subsequent periods of the same duration in 2001, 2002 and 2004. Of the 52,575 deaths in 2003, Croatia recorded 4,682 (8.9%, 95% Confidence interval 8.4-9.4) in the strike period from the 15th of January to the 14th of February 2003 or 1.1 deaths per 1000. No deviations of the 15th of January to the 14th of February period's share of the death total in relation to other observation periods were noted. It is impossible to associate the strike based on the figures shown in this paper with either an increase or decrease in population mortality.     

Leptospirosis distribution related to freshwater habitats in the Vojvodina region (Republic of Serbia)

The retrospective study (2002—2007) for human leptospirosis in Vojvodina was undertaken in order to describe the distribution of the disease in relation with some environmental factors. Regarding the presented results, the major detected number of leptospirosis cases concurs with stagnant waters, wetlands, fish pond areas and protected regions, which comprised the basis for mapping of the region in three risk zones: very high risk (incidence rate higher than 5.0), high risk (2.5—5.0) and medium risk of leptospirosis infection (1.0—2.5). During the investigated period, 97 cases were registered with an average of 13.85 cases per year: 2002, 32 cases; 2003, 7; 2004, 22; 2005, 16; 2006, 4 and 2007, 16. Out of these 97 cases only 5 were women. Serovars from 11 presumptive serogroups caused infection, with a predominance of Icterohaemorrhagiae and Bratislava, accounting for 72.72% of cases together. Icterohaemorrhagiae was the commonest infecting serogroup mostly connected with fish ponds. Case fatality ratio was 9.4%.     

Bone morphogenetic protein (BMP)1-3 enhances bone repair

Small molecules that exhibit biological activity have contributed to the understanding of the molecular mechanisms of various biological phenomena. 5-Bromodeoxyuridine (BrdU) is a thymidine analogue that modulates various biological phenomena such as cellular differentiation and cellular senescence in cultured mammalian cells. Although BrdU is thought to function through changing chromatin structure and gene expression, its precise molecular mechanisms are not understood. To study the molecular mechanism for the action of BrdU, we have employed the yeast Saccharomycescerevisiae as a model system, and screened multi-copy suppressor genes that confer resistance to BrdU. Our genetic screen has revealed that expression of the N-terminal short fragment of TUP1, and also disruption of HDA1 or HOS1, histone deacetylases that interact with TUP1, conferred resistance to BrdU. These results suggest the implication of the chromatin proteins in the function of BrdU, and would provide novel clues to answer the old question of how BrdU modulates various biological phenomena.     

Cation-pi interaction in a folded polypeptide.

Cationic and aromatic side chains from protein residues interact to stabilize tertiary structure. The stabilization energy originates in part from electrostatic attraction between the cation, and regions of high electron density in pi-orbitals of the aromatic group, leading to the name cation-pi interaction. The lysine and tyrosine containing peptide, N-acetyl-Pro-Pro-Lys-Tyr-Asp-Lys-NH(2), has near uv CD characteristic of tyrosine in a structured environment. Nuclear Overhauser effect (NOE), coupling constant, and ring current chemical shift constraints obtained with (1)H NMR confirm that the peptide (t6p) folds. Simulated annealing consistent with all NMR constraints produces a 40-structure ensemble for t6p with potential energies within one standard deviation of the lowest value observed. Calculated binding energies indicate that cation-pi and cation-phenolic OH interactions exists between the Lys3 and Tyr4 side chains in most of the structures. The t6p peptide in solution is a model for these interactions in a protein. A perturbing electric field from the cationic ground state charge intermingles the excited states of the aromatic group. This intermingling effect may provide a cation-pi signature effect in the tyrosine spectroscopy. The absorption and CD for the lowest energy electronic transitions of the tyrosine phenol were computed for the ensemble. Red-shifted peak energy and hypochromicity in the absorbance band, and decreasing rotational strength, correlates with increasing binding energy of the complex indicating the cation-pi spectroscopic signature. The ensemble average spectroscopic signature effects in t6p are small and in agreement with observation.     

Amino-acid Type Identification in 15N-HSQC Spectra by Combinatorial Selective 15N-labelling

The efficiency of cell-free protein synthesis combined with combinatorial selective ¹⁵N-labelling provides a method for the rapid assignment of ¹⁵N-HSQC cross-peaks to the 19 different non-proline amino-acid types from five ¹⁵N-HSQC spectra. This strategy was explored with two different constructs of the C-terminal domain V of the τ subunit of the Escherichia coli DNA polymerase III holoenzyme, τ_C16 and τ_C14. Since each of the five ¹⁵N-HSQC spectra contained only about one third of the cross-peaks present in uniformly labelled samples, spectral overlap was much reduced. All ¹⁵N-HSQC cross-peaks of the backbone amides could be assigned to the correct amino-acid type. Availability of the residue-type information greatly assisted the evaluation of the changes in chemical shifts observed for corresponding residues in τ_C16 vs. those in τ_C14, and the analysis of the structure and mobility of the C-terminal residues present in τ_C16 but not in τ_C14.     

A New Prenylated Flavanonol from Seseli annuum Roots Showing Protective Effect on Human Lymphocytes DNA

A new prenylated flavanonol named seselinonol ( 1 ) was isolated from the roots of Seseli annuum, together with the well‐known biologically active polyacetylenes falcarinol ( 2 ) and falcarindiol ( 3 ), and the prenylated furanocoumarin phellopterin ( 4 ). Its structure was elucidated by extensive spectroscopic analysis, including HR‐ESI‐MS, 1D‐ and 2D‐NMR. Seselinonol and phellopterin were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin‐B blocked micronucleus (CBMN) assay. The new compound exerted a beneficial effect by decreasing DNA damage of human lymphocytes.