Plasma interleukin-1β concentration is associated with stroke in sickle cell disease

The pathogenesis of sickle cell disease (HbSS), which has numerous complications including stroke, involves inflammation resulting in alteration of plasma inflammatory protein concentration. We investigated HbSS children with abnormal cerebral blood flow detected by trans-cranial Doppler ultrasound (TCD) who participated in the multi-center stroke prevention (STOP) study, to determine if plasma inflammatory protein concentration is associated with the outcome of stroke. Thirty-nine plasma samples from HbSS participants with elevated TCD who had no stroke, HbSS-NS (n = 13) or had stroke, HbSS-S (n = 13), HbSS steady-state controls (n = 7) and controls with normal hemoglobin, HbAA (n = 6), were analyzed simultaneously for 27 circulating inflammatory proteins. Logistic regression and receiver operating characteristics curve analysis of stroke on plasma inflammatory mediator concentration, adjusted for age and gender, demonstrated that interleukin-1β (IL-1β) was protective against stroke development (HbSS-NS = 19, 17–23, HbSS-S = 17, 16–19 pg/mL, median and 25th–75th percentile; odds ratio = 0.59, C.I. = 0.36–0.96) and was a good predictor of stroke (area under curve = 0.852). This result demonstrates a strong association of systemic inflammation with stroke development in HbSS via moderately increased plasma IL-1β concentration, which is furthermore associated with a decreased likelihood of stroke in HbSS.     

Structure of a self-splicing group II intron catalytic effector domain 5: parallels with spliceosomal U6 RNA

Domain 5 (D5) is absolutely required for all catalytic functions of group II introns. Here we describe the solution NMR structure, electrostatic calculations, and detailed magnesium ion-binding surface of D5 RNA from the Pylaiella littoralis large ribosomal RNA intron (D5-PL). The overall structure consists of a hairpin capped by a GNRA tetraloop. The stem is divided into lower and upper helices of 8 and 5 bp, respectively, separated by an internal bulge. The D5-PL internal bulge nucleotides stack into the helical junction, resulting in a coupling between the bulge A25 and the closing base pair (G8-C27) of the lower helix. Comparison of the D5-PL structure to previously reported related structures indicates that our structure is most similar, in the helical regions, to the crystal structure of D5 from yeast Ai5gamma (D5-Ai5gamma) and the NMR structure of the U6 snRNA stem-loop region. Our structure differs in many respects from both the NMR and X-ray structures of D5-Ai5gamma in the bulge region. Electrostatic calculations and NMR chemical shift perturbation analyses reveal magnesium ion-binding sites in the tetraloop, internal bulge, and the AGC triad in the lower stem. Our results suggest that the structure, electrostatic environment, and the magnesium ion-binding sites within the tetraloop, bulge, and triad regions are conserved features of the splicing machinery of both the group II introns and the spliceosome that are likely key for catalytic function.     

Dynamic flexibility of double-stranded RNA activated PKR in solution

PKR, an interferon-induced double-stranded RNA activated serine-threonine kinase, is a component of signal transduction pathways mediating cell growth control and responses to stress and viral infection. Analysis of separate PKR functional domains by NMR and X-ray crystallography has revealed details of PKR RNA binding domains and kinase domain, respectively. Here, we report the structural characteristics, calculated from biochemical and neutron scattering data, of a native PKR fraction with a high level of autophosphorylation and constitutive kinase activity. The experiments reveal association of the protein monomer into dimers and tetramers, in the absence of double-stranded RNA or other activators. Low-resolution structures of the association states were obtained from the large angle neutron scattering data and reveal the relative orientation of all protein domains in the activated kinase dimer. Low-resolution structures were also obtained for a PKR tetramer-monoclonal antibody complex. Taken together, this information leads to a new model for the structure of the functioning unit of the enzyme, highlights the flexibility of PKR and sheds light on the mechanism of PKR activation. The results of this study emphasize the usefulness of low-resolution structural studies in solution on large flexible multiple domain proteins.     

Expanded molecular phylogeny of the genus Bicyclus (Lepidoptera: Nymphalidae) shows the importance of increased sampling for detecting semi-cryptic species and highlights potentials for future studies

The genus Bicyclus is one of the largest groups of African butterflies, but due to the generally cryptic nature and seasonal variation of adult wing patterns, there has been a lot of systematic confusion. With a large research community working with the model species Bicyclus anynana there has been increasing interest in the evolutionary history of the genus. A previous phylogeny started to unravel interesting patterns, but only included 61% of the then known species. With a range of new species having been described in the last decade there has been a need for an updated phylogeny for the genus. We present the most complete phylogeny of Bicyclus yet, including 93% of the currently 103 recognized species and make a range of taxonomic revisions. We revise the status of four previous subspecies and synonymized taxa that in the light of the new genetic data are raised to species level. We also subsume two subspecies and describe a new species, Bicyclus collinsi sp. nov., based on both genetic and morphological evidence. A further new taxon is identified, but not described at this point due to lack of morphological data. Our phylogeny lays a solid foundation for better understanding the evolution of Bicyclus and highlights key species-groups and complexes with intriguing ecological patterns making them prime candidates for future studies.

http://zoobank.org/urn:lsid:zoobank.org:pub:2F775351-097E-4CD7-8F8F-A90B26D52DE8     

Associations between Red Cell Polymorphisms and Plasmodium falciparum Infection in the Middle Belt of Ghana

Background

Red blood cell (RBC) polymorphisms are common in malaria endemic regions and are known to protect against severe forms of the disease. Therefore, it is important to screen for these polymorphisms in drugs or vaccines efficacy trials. This study was undertaken to evaluate associations between clinical malaria and RBC polymorphisms to assess biological interactions that may be necessary for consideration when designing clinical trials.

Method

In a cross-sectional study of 341 febrile children less than five years of age, associations between clinical malaria and common RBC polymorphisms including the sickle cell gene and G6PD deficiency was evaluated between November 2008 and June 2009 in the middle belt of Ghana, Kintampo. G6PD deficiency was determined by quantitative methods whiles haemoglobin variants were determined by haemoglobin titan gel electrophoresis. Blood smears were stained with Giemsa and parasite densities were determined microscopically.

Results

The prevalence of clinical malarial among the enrolled children was 31.9%. The frequency of G6PD deficiency was 19.0% and that for the haemoglobin variants were 74.7%, 14.7%, 9.1%, 0.9% respectively for HbAA, HbAC, HbAS and HbSS. In Multivariate regression analysis, children with the HbAS genotype had 79% lower risk of malaria infection compared to those with the HbAA genotypes (OR = 0.21, 95% CI: 0.06–0.73, p = 0.01). HbAC genotype was not significantly associated with malaria infection relative to the HbAA genotype (OR = 0.70, 95% CI: 0.35–1.42, p = 0.33). G6PD deficient subgroup had a marginally increased risk of malaria infection compared to the G6PD normal subgroup (OR = 1.76, 95% CI: 0.98–3.16, p = 0.06).

Conclusion

These results confirm previous findings showing a protective effect of sickle cell trait on clinical malaria infection. However, G6PD deficiency was associated with a marginal increase in susceptibility to clinical malaria compared to children without G6PD deficiency.     

Haematological and biochemical reference values for healthy adults in the middle belt of Ghana

Background

Reference values are very important in clinical management of patients, screening participants for enrolment into clinical trials and for monitoring the onset of adverse events during these trials. The aim of this was to establish gender-specific haematological and biochemical reference values for healthy adults in the central part of Ghana.

Methods

A total of 691 adults between 18 and 59 years resident in the Kintampo North Municipality and South District in the central part of Ghana were randomly selected using the Kintampo Health and Demographic Surveillance System and enrolled in this cross-sectional survey. Out of these, 625 adults made up of 316 males and 309 females were assessed by a clinician to be healthy. Median values and nonparametric 95% reference values for 16 haematology and 22 biochemistry parameters were determined for this population based on the Clinical Laboratory and Standards Institute guidelines. Values established in this study were compared with the Caucasian values being used currently by our laboratory as reference values and also with data from other African and western countries.

Results

Reference values established include: haemoglobin 113–164 g/L for males and 88–144 g/L for females; total white blood cell count 3.4–9.2×10⁹/L; platelet count 88–352×10⁹/L for males and 89–403×10⁹/L for females; alanine aminotransferase 8–54 U/L for males and 6–51 U/L for females; creatinine 56–119 µmol/L for males and 53–106 µmol/L for females. Using the haematological reference values based on the package inserts would have screened out up to 53% of potential trial participants and up to 25% of the population using the biochemical parameters.

Conclusion

We have established a panel of locally relevant reference parameters for commonly used haematological and biochemical tests. This is important as it will help in the interpretation of laboratory results both for clinical management of patients and safety monitoring during a trial.     

Asymmetry of 13C labeled 3-pyruvate affords improved site specific labeling of RNA for NMR spectroscopy

Selective isotopic labeling provides an unparalleled window within which to study the structure and dynamics of RNAs by high resolution NMR spectroscopy. Unlike commonly used carbon sources, the asymmetry of ¹³C-labeled pyruvate provides selective labeling in both the ribose and base moieties of nucleotides using Escherichia coli variants, that until now were not feasible. Here we show that an E. coli mutant strain that lacks succinate and malate dehydrogenases (DL323) and grown on [3-¹³C]-pyruvate affords ribonucleotides with site specific labeling at C5′ (~95%) and C1′ (~42%) and minimal enrichment elsewhere in the ribose ring. Enrichment is also achieved at purine C2 and C8 (~95%) and pyrimidine C5 (~100%) positions with minimal labeling at pyrimidine C6 and purine C5 positions. These labeling patterns contrast with those obtained with DL323 E. coli grown on [1, 3-¹³C]-glycerol for which the ribose ring is labeled in all but the C4′ carbon position, leading to multiplet splitting of the C1′, C2′ and C3′ carbon atoms. The usefulness of these labeling patterns is demonstrated with a 27-nt RNA fragment derived from the 30S ribosomal subunit. Removal of the strong magnetic coupling within the ribose and base leads to increased sensitivity, substantial simplification of NMR spectra, and more precise and accurate dynamic parameters derived from NMR relaxation measurements. Thus these new labels offer valuable probes for characterizing the structure and dynamics of RNA that were previously limited by the constraint of uniformly labeled nucleotides.     

Biomass production of site selective 13C/15N nucleotides using wild type and a transketolase E. coli mutant for labeling RNA for high resolution NMR

Characterization of the structure and dynamics of nucleic acids by NMR benefits significantly from position specifically labeled nucleotides. Here an E. coli strain deficient in the transketolase gene (tktA) and grown on glucose that is labeled at different carbon sites is shown to facilitate cost-effective and large scale production of useful nucleotides. These nucleotides are site specifically labeled in C1′ and C5′ with minimal scrambling within the ribose ring. To demonstrate the utility of this labeling approach, the new site-specific labeled and the uniformly labeled nucleotides were used to synthesize a 36-nt RNA containing the catalytically essential domain 5 (D5) of the brown algae group II intron self-splicing ribozyme. The D5 RNA was used in binding and relaxation studies probed by NMR spectroscopy. Key nucleotides in the D5 RNA that are implicated in binding Mg²⁺ ions are well resolved. As a result, spectra obtained using selectively labeled nucleotides have higher signal-to-noise ratio compared to those obtained using uniformly labeled nucleotides. Thus, compared to the uniformly ¹³C/¹⁵N-labeled nucleotides, these specifically labeled nucleotides eliminate the extensive ¹³C–¹³C coupling within the nitrogenous base and ribose ring, give rise to less crowded and more resolved NMR spectra, and accurate relaxation rates without the need for constant-time or band-selective decoupled NMR experiments. These position selective labeled nucleotides should, therefore, find wide use in NMR analysis of biologically interesting RNA molecules.     

Differential binding of 2'-biotinylated analogs of c-di-GMP with c-di-GMP riboswitches and binding proteins

C-di-GMP has emerged as a signalling molecule that regulates a variety of processes in several bacteria; therefore there is interest in the development of biotinylated analogs for the identification of binding partners. No detailed study has been done to evaluate if biotinylated analogs of c-di-GMP are capable of binding to c-di-GMP receptors. Herein, we evaluate the binding of commercially available 2'-biotinylated c-di-GMP and phosphorothioate 2'-biotinylated c-di-GMP, prepared via a facile solid-phase synthesis, to several c-di-GMP receptors. Docking, using Autodock vina software, as well as experimental studies of these analogs, with c-di-GMP class I and II riboswitches and binding proteins, reveal that some, but not all, c-di-GMP receptors can tolerate the 2'-modification of c-di-GMP with biotin.     

Psychological health and religious coping of Ghanaian women with infertility

Background

Infertility has been shown to have considerable psychological effects on the well-being of couples, especially women. Religion has been found as a resource used by infertile women to cope with their distress. Little research has examined the influence of religious coping on psychological distress among infertile women in Ghana. This study examines the relationship between positive and negative religious coping and psychological health for women with infertility problems in Ghana.

Methods

One hundred and fifty married women who were receiving assisted reproduction care in two specialized clinics were recruited for this study. Participants were administered with the Brief Symptom Inventory and Brief Religious Coping Scale to assess psychological health associated with infertility and religious coping respectively. A hierarchical regression was performed to examine the relative contribution of the domains of psychological health (i.e. somatization, anxiety and depression) in predicting negative religious coping and positive religious.

Results

The results showed that negative religious coping was significant and positively correlated with somatization, depression and anxiety. Furthermore, a positive relationship also existed between positive religious coping and somatization and anxiety but not depression. After controlling for age and duration of infertility, somatization and anxiety predicted positive religious coping whilst all the domains of psychological health (somatization, anxiety and depression) precited negative religious coping.

Conclusions

This study expanded on the existing literature by examining positive and negative religious coping with psychological distress associated with infertility for women. These results underscore the need for health professionals providing therapies for women with infertility to acknowledge and consider their religious beliefs as this influences their mental health.