The genome of Syntrophomonas wolfei: new insights into syntrophic metabolism and biohydrogen production

Syntrophomonas wolfei is a specialist, evolutionarily adapted for syntrophic growth with methanogens and other hydrogen- and/or formate-using microorganisms. This slow-growing anaerobe has three putative ribosome RNA operons, each of which has 16S rRNA and 23S rRNA genes of different length and multiple 5S rRNA genes. The genome also contains 10 RNA-directed, DNA polymerase genes. Genomic analysis shows that S. wolfei relies solely on the reduction of protons, bicarbonate or unsaturated fatty acids to re-oxidize reduced cofactors. Syntrophomonas wolfei lacks the genes needed for aerobic or anaerobic respiration and has an exceptionally limited ability to create ion gradients. An ATP synthase and a pyrophosphatase were the only systems detected capable of creating an ion gradient. Multiple homologues for β-oxidation genes were present even though S. wolfei uses a limited range of fatty acids from four to eight carbons in length.Syntrophomonas wolfei, other syntrophic metabolizers with completed genomic sequences, and thermophilic anaerobes known to produce high molar ratios of hydrogen from glucose have genes to produce H(2) from NADH by an electron bifurcation mechanism. Comparative genomic analysis also suggests that formate production from NADH may involve electron bifurcation. A membrane-bound, iron-sulfur oxidoreductase found in S. wolfei and Syntrophus aciditrophicus may be uniquely involved in reverse electron transport during syntrophic fatty acid metabolism. The genome sequence of S. wolfei reveals several core reactions that may be characteristic of syntrophic fatty acid metabolism and illustrates how biological systems produce hydrogen from thermodynamically difficult reactions.     

The role of B cell CD22 expression in Staphylococcus aureus arthritis and sepsis

Severe Staphylococcus aureus infections give rise to a pronounced antigen-specific and polyclonal B cell response with elevated serum immunoglobulin levels. However, it has been difficult to correlate the antibody levels with the clinical outcome of sepsis and/or arthritis concerning both protection and pathogenic aspects. Earlier studies have shown that macrophages and neutrophils are of great importance for bacterial clearance. However, deletion of the complete B cell compartment affected neither S. aureus-induced arthritis nor survival. MZ B cells are believed to be of importance for clearance of blood-borne antigens and have been implicated in protection against S. aureus infections. CD22 is a B-cell-specific inhibitory receptor binding to alpha2,6-linked sialic acids, and deficiency in CD22 leads to a 75% reduction of the MZ B cell compartment. CD22-/- mice and congeneic controls were inoculated intravenously with an arthritogenic dose of live S. aureus. No differences between the groups were detected regarding frequency and severity of arthritis, survival, bacterial clearance, or induction of inflammatory response. This study shows explicitly that a reduced MZ B cell compartment in the absence of CD22 expression does not interfere with the inflammatory response during S. aureus infection.     

Climatic and temporal effects on the expression of secondary sexual characters: genetic and environmental components

Despite great interest in sexual selection, relatively little is known in detail about the genetic and environmental determinants of secondary sexual characters in natural populations. Such information is important for determining the way in which populations may respond to sexual selection. We report analyses of genetic and large-scale environmental components of phenotypic variation of two secondary sexual plumage characters (forehead and wing patch size) in the collared flycatcher Ficedula albicollis over a 22-year period. We found significant heritability for both characters but little genetic covariance between the two. We found a positive association between forehead patch size and a large-scale climatic index, the North Atlantic Oscillation (NAO) index, but not for wing patch. This pattern was observed in both cross-sectional and longitudinal data suggesting that the population response to NAO index can be explained as the result of phenotypic plasticity. Heritability of forehead patch size for old males, calculated under favorable conditions (NAO index > or = median), was greater than that under unfavorable conditions (NAO index < median). These changes occurred because there were opposing changes in additive genetic variance (VA) and residual variance (VR) under favorable and unfavorable conditions, with VA increasing and VR decreasing in good environments. However, no such effect was detected for young birds, or for wing patch size in either age class. In addition to these environmental effects on both phenotypic and genetic variances, we found evidence for a significant decrease of forehead patch size over time in older birds. This change appears to be caused by a change in the sign of viability selection on forehead patch size, which is associated with a decline in the breeding value of multiple breeders. Our data thus reveal complex patterns of environmental influence on the expression of secondary sexual characters, which may have important implications for understanding selection and evolution of these characters.     

Cost-Effectiveness of Peer Counselling for the Promotion of Exclusive Breastfeeding in Uganda

Background

Community based breastfeeding promotion programmes have been shown to be effective in increasing breastfeeding prevalence. However, there is limited data on the cost-effectiveness of these programmes in sub-Saharan Africa. This paper evaluates the cost-effectiveness of a breastfeeding promotion intervention targeting mothers and their 0 to 6 month old children.

Methods

Data were obtained from a community randomized trial conducted in Uganda between 2006–2008, and supplemented with evidence from several studies in sub-Saharan Africa. In the trial, peer counselling was offered to women in intervention clusters. In the control and intervention clusters, women could access standard health facility breastfeeding promotion services (HFP). Thus, two methods of breastfeeding promotion were compared: community based peer counselling (in addition to HFP) and standard HFP alone. A Markov model was used to calculate incremental cost-effectiveness ratios between the two strategies. The model estimated changes in breastfeeding prevalence and disability adjusted life years. Costs were estimated from a provider perspective. Uncertainty around the results was characterized using one-way sensitivity analyses and a probabilistic sensitivity analysis.

Findings

Peer counselling more than doubled the breastfeeding prevalence as reported by mothers, but there was no observable impact on diarrhoea prevalence. Estimated incremental cost-effectiveness ratios were US$68 per month of exclusive or predominant breastfeeding and U$11,353 per disability adjusted life year (DALY) averted. The findings were robust to parameter variations in the sensitivity analyses

Conclusions

Our strategy to promote community based peer counselling is unlikely to be cost-effective in reducing diarrhoea prevalence and mortality in Uganda, because its cost per DALY averted far exceeds the commonly assumed willingness-to-pay threshold of three times Uganda’s GDP per capita (US$1653). However, since the intervention significantly increases prevalence of exclusive or predominant breastfeeding, it could be adopted in Uganda if benefits other than reducing the occurrence of diarrhoea are believed to be important.     

Chemico-structure of the organophosphatic shells of siphonotretide brachiopods

The organophosphatic shell of siphonotretide brachiopods is stratiform with orthodoxly secreted primary and secondary layers. The dominant apatitic constituents of the secondary layer are prismatic laths and rods arranged in monolayers (occasionally in cross-bladed successions), normally recrystallized as platy laminae. Sporadically distributed, interlaminar, lenticular chambers, containing apatitic meshes of laths and aggregates of plates and spherulites, probably represent degraded, localized exudations of glycosaminoglycans (GAGs) with dispersed apatite.
The shells of Helmersenia and Gorchakovia are perforated by canals with external depressions (antechambers) that possibly contained chitinous tubercles in vivo . The immature shell of Siphonotreta and most other siphonotretids is similarly perforated and pitted; but the mature part bears recumbent, rheomorphic, hollow spines that grew forward out of pits. Internally, spines pierce the shell as independent structures to terminate as pillars in GAGs chambers. Spines and pillars were probably secreted by collectives of specialized cells (acanthoblasts) within the mantle.
The shell of the oldest siphonotretide, Schizambon , is imperforate but the ventral valve has a pedicle foramen that lies forward of the posterior margin of the juvenile valve. This relationship characterizes all siphonotretides, suggesting that the pedicle, in vivo , originated within the ventral outer epithelium and not from the posterior body wall as in lingulides.     

Nicastrin, presenilin, APH-1, and PEN-2 form active gamma-secretase complexes in mitochondria

Mitochondria are central in the regulation of cell death. Apart from providing the cell with ATP, mitochondria also harbor several death factors that are released upon apoptotic stimuli. Alterations in mitochondrial functions, increased oxidative stress, and neurons dying by apoptosis have been detected in Alzheimer's disease patients. These findings suggest that mitochondria may trigger the abnormal onset of neuronal cell death in Alzheimer's disease. We previously reported that presenilin 1 (PS1), which is often mutated in familial forms of Alzheimer's disease, is located in mitochondria and hypothesized that presenilin mutations may sensitize cells to apoptotic stimuli at the mitochondrial level. Presenilin forms an active gamma-secretase complex together with Nicastrin (NCT), APH-1, and PEN-2, which among other substrates cleaves the beta-amyloid precursor protein (beta-APP) generating the amyloid beta-peptide and the beta-APP intracellular domain. Here we have identified dual targeting sequences (for endoplasmic reticulum and mitochondria) in NCT and showed expression of NCT in mitochondria by immunoelectron microscopy. We also showed that NCT together with APH-1, PEN-2, and PS1 form a high molecular weight complex located in mitochondria. gamma-secretase activity in isolated mitochondria was demonstrated using C83 (alpha-secretase-cleaved C-terminal 83-residue beta-APP fragment from BD8 cells lacking presenilin and thus gamma-secretase activity) or recombinant C100-Flag (C-terminal 100-residue beta-APP fragment) as substrates. Both systems generated an APP intracellular domain, and the activity was inhibited by the gamma-secretase inhibitors l-685,458 or Compound E. This novel localization of NCT, PS1, APH-1, and PEN-2 expands the role and importance of gamma-secretase activity to mitochondria.     

Improvement of anther culture technique: Activated charcoal bound in agar medium in combination with liquid medium and elevated CO2 concentration

Anthers of different species of the genera Anemone, Clematis, Papaver and Nicotiana were cultured by floating on a liquid medium which overlay an agarified charcoal medium . This technique proved to be superior to conventional methods i.e. culture on either solid or liquid media. Cold treatment of Anemone anthers for 7 days after inoculation on the double layer medium gave about the same frequency of embryos per anther as corresponding cultures cold treated before inoculation. An elevation of the CO₂ concentration to 2% stimulated embryogenesis in anther cultures of Anemone canadensis, Anemone vitifolia, Papaver setigerum and Papaver radicatum . Cold treatment of cultures of Anemone canadensis inhibited embryogenesis if the ensuing culture was performed in 2% CO_2. On the other hand, cold treatment was stimulating, with an optimum of about 20 days, if the cultures were maintained in normal air. Chemical analysis of untreated anthers of Anemone canadensis showed the presence of abscisic acid (2.2 × 10⁻⁶ g/g anthers). Cold treatment reduced the concentration of abscisic acid to 0.6 × 10⁻⁶ g/g anthers. By use of assays with Lemna gibba as test organism, activated charcoal was shown to adsorb abscisic acid that was added to the medium. Medium treated with charcoal before inoculation of anthers of Anemone canadensis provided to inhibit embryo production.     

Reinstitutionalisation in mental health care: comparison of data on service provision from six European countries

Objective To establish whether reinstitutionalisation is occurring in mental health care and, if so, with what variations between western European countries.Design Comparison of data on changes in service provision.Setting Six European countries with different traditions of mental health care that have all experienced deinstitutionalisation since the 1970s—England, Germany, Italy, the Netherlands, Spain, and Sweden.Outcome measures Changes in the number of forensic hospital beds, involuntary hospital admissions, places in supported housing, general psychiatric hospital beds, and general prison population between 1990-1 and 2002-3.Results Forensic beds and places in supported housing have increased in all countries, whereas changes in involuntary hospital admissions have been inconsistent. The number of psychiatric hospital beds has been reduced in five countries, but only in two countries does this reduction outweigh the number of additional places in forensic institutions and supported housing. The general prison population has substantially increased in all countries.Conclusions Reinstitutionalisation is taking place in European countries with different traditions of health care, although with significant variation between the six countries studied. The precise reasons for the phenomenon remain unclear. General attitudes to risk containment in a society, as indicated by the size of the prison population, may be more important than changing morbidity and new methods of mental healthcare delivery.     

Tetrahydrobiopterin restores endothelial dysfunction induced by an oral glucose challenge in healthy subjects

An oral glucose challenge causes transient impairment of endothelial function, probably because of increased oxidative stress. During oxidative stress, endothelial nitric oxide (NO) synthase (eNOS) becomes uncoupled because of decreased bioavailability of tetrahydrobiopterin (BH4), an essential cofactor of eNOS. Therefore, we examined whether an acute supplement of BH4 could restore endothelial dysfunction induced by an oral glucose challenge. Healthy subjects were examined in 53 experiments. Forearm blood flow was measured by venous occlusion plethysmography. Dose-response studies were obtained during intra-arterial infusion of serotonin to elicit endothelium-dependent, NO-specific vasodilation and during sodium nitroprusside (SNP) infusion to elicit endothelium-independent vasodilation. Subjects were examined before (fasting) and 1 and 2 h after an oral glucose challenge (75 g) with serotonin (n = 10) and SNP (n = 8). On different days (6R)-5,6,7,8-tetrahydro-l-biopterin dihydrochloride (6R-BH4; n = 10), the active cofactor of eNOS or its stereoisomer (6S)-5,6,7,8-tetrahydro-l-biopterin sulfate (6S-BH4; n = 10), which is inactive as a cofactor, was added 10 min (500 microg/min) before and during the 1-h postchallenge serotonin dose-response study. In vitro studies showed that 6R-BH4 and 6S-BH4 were equipotent antioxidants. Serotonin response was reduced by 24 +/- 7% (at the highest dose) at 1 h postchallenge compared with fasting (P = 0.001) and was restored 2 h postchallenge. The reduction was reversed by the administration of 6R-BH4 but not by 6S-BH4. SNP responses were slightly increased 1 and 2 h postchallenge (increased by 15 +/- 13% at third dose 2 h postchallenge, P = 0.0001). An oral glucose challenge causes transient, NO-specific, endothelial dysfunction, which may be reversed by BH4. Transient postprandial endothelial dysfunction may be partly explained by reduced bioavailability of BH4 and NO.