Social determinants of health--a comparative study of Bosnian adolescents in different cultural contexts

This study investigated the effects of sociocultural contexts on health and the psychological well-being of immigrant adolescents, aged 15 to 18 years, originally from Bosnia and Herzegovina and now living as displaced persons either in Bosnia, or immigrants in Croatia and Austria. The study addresses the social determinants of health with a specific focus on five factors in the social environment that might have an influence on health status: gender, socio-economic status (SES), perceived discrimination and exposure to violence, social support and religious commitment. Dependent variables included self-rated health, a count of self-reported objective health problems and a range of indices of psychological well-being (somatic stress, anxiety, depression and self-esteem). The purpose of the study was to examine whether social risk factors have an effect on health, which factors mediate these effects on self-rated health and to assess whether these effects differ by gender Results indicate that perceived discrimination and violence are related to poor health through psychological stress as a major mechanism with stronger effects for girls in the study. Differences across the three socio-cultural contexts reveal the complexity and specificity of the relationships between analyzed factors as the association between discrimination and health was attenuated for some groups due to the protective resources of immigrants.     

Inhibitors of casein kinase 1 block the growth of Leishmania major promastigotes in vitro

Casein kinase 1 (CK1) is a family of multifunctional Ser/Thr protein kinases that are ubiquitous in eukaryotic cells. Recent studies have demonstrated the existence of, and role for, CK1 in protozoan parasites such as Leishmania, Plasmodium and Trypanosoma. The value of protein kinases as potential drug targets in protozoa is evidenced by the successful exploitation of cyclic guanosine monophosphate-dependent protein kinase (PKG) with selective tri-substituted pyrrole and imidazopyridine inhibitors. These compounds exhibit in vivo efficacy against Eimeria tenella in chickens and Toxoplasma gondii in mice. We now report that both of these protein kinase inhibitor classes inhibit the growth of Leishmania major promastigotes and Trypanosoma brucei bloodstream forms in vitro. Genome informatics predicts that neither of these trypanosomatids codes for a PKG orthologue. Biochemical studies have led to the unexpected discovery that an isoform of CK1 represents the primary target of the pyrrole and imidazopyridine kinase inhibitors in these organisms. CK1 from extracts of L. major promastigotes co-fractionated with [(3)H]imidazopyridine binding activity. Further purification of CK1 activity from L. major and characterization via liquid chromatography coupled tandem mass spectrometry identified CK1 isoform 2 as the specific parasite protein inhibited by imidazopyridines. L. major CK1 isoform 2 expressed as a recombinant protein in Escherichia coli displayed biochemical and inhibition characteristics similar to those of the purified native enzyme. The results described here warrant further evaluation of the activity of these kinase inhibitors against mammalian stage Leishmania parasites in vitro and in animal models of infection, as well as studies to genetically validate CK1 as a therapeutic target in trypanosomatid parasites.     

Characterization of the tandem GAF domain of human phosphodiesterase 5 using a cyanobacterial adenylyl cyclase as a reporter enzyme

We analyzed cGMP signaling by the human phosphodiesterase 5 (hPDE5) tandem GAF domain based on a functional activation assay. The C-terminal catalytic domain of the cyanobacterial adenylyl cyclase (AC) cyaB1 was used as a reporter enzyme. We demonstrate functional coupling between the hPDE5 GAF ensemble and the AC resulting in a chimera stimulated 10-fold by cGMP. The hPDE5 GAF domain has an inhibitory effect on AC activity, which is released upon cGMP activation. Removal of 109 amino acids from the N terminus resulted in partial disengagement of the GAF domain and AC, i.e. in a 10-fold increase in basal activity, and affected cGMP affinity. The Ser-102 phosphorylation site of hPDE5 increased cGMP affinity, as shown by a 5-fold lower K(D) for cGMP in a S102D mutant, which mimicked complete modification. The function of the NKFDE motif, which is a signature of all GAF domains with known cyclic nucleotide binding capacity, was elucidated by targeted mutations. Data with either single and double mutants in either GAF A or GAF B or a quadruple mutant affecting both subdomains simultaneously indicated that it is impossible to functionally assign cGMP binding and intramolecular signaling to either GAF A or B of hPDE5. Both subdomains are structurally and functionally interdependent and act in concert in regulating cycaB1 AC and, most likely, also hPDE5.     

Calcitriol Protection against Dopamine Loss Induced by Intracerebroventricular Administration of 6-Hydroxydopamine

Calcitriol has been implicated as an agent that has neuroprotective effects in various animal models of diseases, possibly by upregulating glial cell line-derived neurotrophic factor (GDNF). The present study examined the neuroprotective effects of calcitriol in a model of early Parkinson’s disease. Rats were treated daily with calcitriol or saline for 7 days before an intraventricular injection of 6-hydroxydopamine (6-OHDA), and then for 1 day or daily for 3½ to 4 weeks after lesioning. Evoked overflow and tissue content of dopamine (DA) were determined 3½ to 4 weeks post lesion. The 8-day calcitriol treatment did not attenuate 6-OHDA-induced decreases in evoked overflow of DA, nor did it protect against 6-OHDA-induced reductions in tissue levels of DA in the striatum or substantia nigra. However, the long-term calcitriol treatment did significantly increase evoked overflow of DA, as well as the amount of DA in the striatum, compared to saline treated animals. GDNF was significantly increased in the substantia nigra, but not in the striatum, of non-lesioned, calcitriol treated rats. These results suggest that long-term treatment with calcitriol can provide partial protection for dopaminergic neurons against the effects of intraventricularly administered 6-OHDA.     

Chemical Nature of Phagostimulants in Pollen Attractive to Honeybees

Honey bees display a powerful ability to recognize pollen from most plants as food and non-pollen materials as not being food. We sequentially extracted a mixed species blend of pollen with a range of non polar to polar solvents and tested the extracts for attractiveness and feeding enhancement by young bees. Both non polar and polar materials were independently attractive when added in trace quantities to a plain artificial diet. The attractants have little inherent nutritional value, as addition of phagostimulants to artificial diets did not increase the life spans of bees compared to phagostimulant-free diets. These data indicate that pollen phagostimulants consist not of a single or a few specific compounds, but rather are a suite of diverse components that additively or synergistically serve to exceed a threshold level of stimulation necessary for feeding.     

A Wnt1-regulated genetic network controls the identity and fate of midbrain-dopaminergic progenitors in vivo

Midbrain neurons synthesizing the neurotransmitter dopamine play a central role in the modulation of different brain functions and are associated with major neurological and psychiatric disorders. Despite the importance of these cells, the molecular mechanisms controlling their development are still poorly understood. The secreted glycoprotein Wnt1 is expressed in close vicinity to developing midbrain dopaminergic neurons. Here, we show that Wnt1 regulates the genetic network, including Otx2 and Nkx2-2, that is required for the establishment of the midbrain dopaminergic progenitor domain during embryonic development. In addition, Wnt1 is required for the terminal differentiation of midbrain dopaminergic neurons at later stages of embryogenesis. These results identify Wnt1 as a key molecule in the development of midbrain dopaminergic neurons in vivo. They also suggest the Wnt1-controlled signaling pathway as a promising target for new therapeutic strategies in the treatment of Parkinson's disease.     

Design and synthesis of 2,3,4,9-tetrahydro-1H-carbazole and 1,2,3,4-tetrahydro-cyclopenta[b]indole derivatives as non-nucleoside inhibitors of hepatitis C virus NS5B RNA-dependent RNA polymerase

A novel class of HCV NS5B RNA dependent RNA polymerase inhibitors containing 2,3,4,9-tetrahydro-1H-carbazole and 1,2,3,4-tetrahydro-cyclopenta[b]indole scaffolds were designed and synthesized. Optimization of the aromatic region showed preference for 5,8-disubstitution pattern in both the scaffolds examined while favoring the n-propyl moiety for the C-1 position. 1,2,3,4-tetrahydro-cyclopenta[b]indole scaffold was slightly more potent than the corresponding 2,3,4,9-tetrahydro-1H-carbazole and analogue 36 displayed an IC50 of 550 nM against HCV NS5B enzyme.     

MEL-28 is downstream of the Ran cycle and is required for nuclear-envelope function and chromatin maintenance

Early embryonic development depends on the faithful execution of basic cell biological processes whose coordination remains largely unknown. With a global network analysis, we found MEL-28 to be associated with two types of complexes, one implicated in nuclear-envelope function and the other in chromatin organization. Here, we show that MEL-28, a protein that shuttles between the nucleus and the kinetochore during the cell cycle, is required for the structural and functional integrity of the nuclear envelope. In addition, mel-28(RNAi) embryos exhibit defects in chromosome condensation, pronuclear migration, kinetochore assembly, and spindle assembly. This combination of mel-28(RNAi) phenotypes resemble those caused by depleting members of the Ran cycle in C. elegans, a conserved cellular signaling pathway that is required for mitotic spindle assembly, nuclear-envelope reformation after mitosis, and nucleocytoplasmic exchange (reviewed in). Although MEL-28 localization to the nuclear periphery is not dependent on nuclear pore components, it is dependent on RAN-1 and other key components of the Ran cycle. Thus, MEL-28 is downstream of the Ran cycle and is required for both proper nuclear-envelope function and chromatin maintenance.     

Bacterial community changes in TCE biodegradation detected in microcosm experiments

Laboratory microcosm experiments were set up to model biodegradation of trichloroethylene (TCE). Groundwater samples from two contaminated sites were taken, one of them with low (70 mg L⁻¹), the other with high sulfate (685 mg L⁻¹) concentration. In order to assess the biodegradative potential of natural microbiota, supplementary substrates (whey or molasses) were added to the bottles. At day 54, 98, 155, and 318, chemical and bacteriological parameters (i.e., Dehalococcoides test) were investigated. Terminal restriction fragment length polymorphism (T-RFLP) based diversity assessments were carried out to observe the bacterial community changes. Whey and molasses enhanced degradation at different rates. In the case of samples with high sulfate content and amended with whey, no ethylene, ethane, or methane was generated. Both ethylene and methane production was detected in samples of low sulfate content with added whey. The results of Dehalococcoides tests were positive for all control and amended samples. Based on T-RFLP analysis, the bacterial communities of high sulfate concentration groundwater microcosms amended with molasses or whey were very similar, while the communities of groundwater samples with low sulfate concentration were different when supplemented with whey or molasses. The rRNA and rDNA based investigations suggest that the proportions of the active microbes and the microbes present in the microcosms differ.