Enhanced abundance and activity of the chloroplast ATP synthase in rice through the overexpression of the AtpD subunit

ATP, produced by the light reactions of photosynthesis, acts as the universal cellular energy cofactor fuelling all life processes. Chloroplast ATP synthase produces ATP using the proton motive force created by solar energy-driven thylakoid electron transport reactions. Here we investigate how increasing abundance of ATP synthase affects leaf photosynthesis and growth of rice, Oryza sativa variety Kitaake. We show that overexpression of AtpD, the nuclear-encoded subunit of the chloroplast ATP synthase, stimulates both abundance of the complex, confirmed by immunodetection of thylakoid complexes separated by Blue Native-PAGE, and ATP synthase activity, detected as higher proton conductivity of the thylakoid membrane. Plants with increased AtpD content had higher CO2 assimilation rates when a stepwise increase in CO2 partial pressure was imposed on leaves at high irradiance. Fitting of the CO2 response curves of assimilation revealed that plants overexpressing AtpD had a higher electron transport rate (J) at high CO2, despite having wild-type-like abundance of the cytochrome b6f complex. A higher maximum carboxylation rate (Vcmax) and lower cyclic electron flow detected in transgenic plants both pointed to an increased ATP production compared with wild-type plants. Our results present evidence that the activity of ATP synthase modulates the rate of electron transport at high CO2 and high irradiance.

Tissue and cell-specific transcriptomes in cotton reveal the subtleties of gene regulation underlying the diversity of plant secondary cell walls

BACKGROUND

Knowledge of plant secondary cell wall (SCW) regulation and deposition is mainly based on the Arabidopsis model of a 'typical' lignocellulosic SCW. However, SCWs in other plants can vary from this. The SCW of mature cotton seed fibres is highly cellulosic and lacks lignification whereas xylem SCWs are lignocellulosic. We used cotton as a model to study different SCWs and the expression of the genes involved in their formation via RNA deep sequencing and chemical analysis of stem and seed fibre.

RESULTS

Transcriptome comparisons from cotton xylem and pith as well as from a developmental series of seed fibres revealed tissue-specific and developmentally regulated expression of several NAC transcription factors some of which are likely to be important as top tier regulators of SCW formation in xylem and/or seed fibre. A so far undescribed hierarchy was identified between the top tier NAC transcription factors SND1-like and NST1/2 in cotton. Key SCW MYB transcription factors, homologs of Arabidopsis MYB46/83, were practically absent in cotton stem xylem. Lack of expression of other lignin-specific MYBs in seed fibre relative to xylem could account for the lack of lignin deposition in seed fibre. Expression of a MYB103 homolog correlated with temporal expression of SCW CesAs and cellulose synthesis in seed fibres. FLAs were highly expressed and may be important structural components of seed fibre SCWs. Finally, we made the unexpected observation that cell walls in the pith of cotton stems contained lignin and had a higher S:G ratio than in xylem, despite that tissue's lacking many of the gene transcripts normally associated with lignin biosynthesis.

CONCLUSIONS

Our study in cotton confirmed some features of the currently accepted gene regulatory cascade for 'typical' plant SCWs, but also revealed substantial differences, especially with key downstream NACs and MYBs. The lignocellulosic SCW of cotton xylem appears to be achieved differently from that in Arabidopsis. Pith cell walls in cotton stems are compositionally very different from that reported for other plant species, including Arabidopsis. The current definition of a 'typical' primary or secondary cell wall might not be applicable to all cell types in all plant species.

Long-term opioid therapy in Denmark: A disappointing journey

BACKGROUND

Longitudinal population-based studies of long-term opioid therapy (L-TOT) in chronic non-cancer pain (CNCP) patients are sparse. Our study investigated incidence and predictors for initiating L-TOT and changes in self-rated health, pain interference and physical activities in long-term opioid users.

METHODS

Data were obtained from the national representative Danish Health and Morbidity Surveys and The Danish National Prescription Registry. Respondents with no dispensed opioids the year before the survey were followed from 2000 and from 2005 until the end of 2012 (n = 12,145). A nationally representative subsample of individuals (n = 2015) completed the self-administered questionnaire in both 2000 and 2013. Collected information included chronic pain (≥6 months), health behaviour, self-rated health, pain interference with work activities and physical activities. Long-term users were defined as those who were dispensed at least one opioid prescription in six separate months within a year.

RESULTS

The incidence of L-TOT was substantially higher in CNCP patients at baseline than in others (9/1000 vs. 2/1000 person-years). Smoking behaviour and dispensed benzodiazepines were significantly associated with initiation of L-TOT in individuals with CNCP at baseline. During follow-up, L-TOT in CNCP patients increased the likelihood of negative changes in pain interference with work (OR 9.2; 95% CI 1.9-43.6) and in moderate activities (OR 3.7; 95% CI 1.1-12.6). The analysis of all individuals indicated a dose-response relationship between longer treatment duration and the risk of experiencing negative changes.

CONCLUSIONS

Individuals on L-TOT seemed not to achieve the key goals of opioid therapy: pain relief, improved quality of life and functional capacity.

SIGNIFICANCE

Long-term opioid therapy does not seem to provide pain relief, improvement in HRQOL and physical capacity in CNCP patients in a general population.

Chronic non-cancer pain and the epidemic prescription of opioids in the Danish population: trends from 2000 to 2013

BACKGROUND

Chronic pain has serious consequences for individuals and society. In addition, opioid prescription for chronic non-cancer pain (CNCP) has become more frequent. This study aims to examine the trends regarding the prevalence of CNCP, dispensed opioids, and concurrent use of benzodiazepine (BZD)/BZD-related drugs in the Danish population.

METHODS

Data from the cross-sectional national representative Danish Health and Morbidity Surveys (2000, 2005, 2010, and 2013) were combined with The Danish National Prescription Registry at an individual level. The study populations varied between 5000 and 13,000 individuals ≥16 years (response rates: 51-63%). Respondents completed a self-administered questionnaire, which included the analyzed items on identification of chronic pain (≥6 months).

RESULTS

From 2000 to 2013, the prevalence of CNCP increased and subsequently the annual prevalence of opioid use from 4.1% to 5.7% among CNCP individuals. Higher CNCP prevalence was related to female gender, no cohabitation partner, short education, non-Western origin, and overweight/obesity. In addition, women with CNCP, especially >65 years, became more frequent users of opioids and used higher doses than men. Concurrent use of BZD/BZD-related drugs decreased (13%) from 2010 to 2013, still one-third of long-term opioid user were co-medicated with these drugs.

CONCLUSIONS

The use of opioids has increased in Denmark, especially among elderly women. The concurrent use of BZD/BZD-related drugs has decreased from 2010 to 2013, but still one-third of long-term opioid users were co-medicated.

Sulfide detoxification in plant mitochondria

In contrast to animals, which release the signal molecule sulfide in small amounts from cysteine and its derivates, phototrophic eukaryotes generate sulfide as an essential intermediate of the sulfur assimilation pathway. Additionally, iron-sulfur cluster turnover and cyanide detoxification might contribute to the release of sulfide in mitochondria. However, sulfide is a potent inhibitor of cytochrome c oxidase in mitochondria. Thus, efficient sulfide detoxification mechanisms are required in mitochondria to ensure adequate energy production and consequently survival of the plant cell. Two enzymes have been recently described to catalyze sulfide detoxification in mitochondria of Arabidopsis thaliana, O-acetylserine(thiol)lyase C (OAS-TL C), and the sulfur dioxygenase (SDO) ethylmalonic encephalopathy protein 1 (ETHE1). Biochemical characterization of sulfide producing and consuming enzymes in mitochondria of plants is fundamental to understand the regulatory network that enables mitochondrial sulfide homeostasis under nonstressed and stressed conditions. In this chapter, we provide established protocols to determine the activity of the sulfide releasing enzyme β-cyanoalanine synthase as well as sulfide-consuming enzymes OAS-TL and SDO. Additionally, we describe a reliable and efficient method to purify OAS-TL proteins from plant material.

The mitochondrial sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 is required for amino acid catabolism during carbohydrate starvation and embryo development in Arabidopsis

The sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1) catalyzes the oxidation of persulfides in the mitochondrial matrix and is essential for early embryo development in Arabidopsis (Arabidopsis thaliana). We investigated the biochemical and physiological functions of ETHE1 in plant metabolism using recombinant Arabidopsis ETHE1 and three transfer DNA insertion lines with 50% to 99% decreased sulfur dioxygenase activity. Our results identified a new mitochondrial pathway catalyzing the detoxification of reduced sulfur species derived from cysteine catabolism by oxidation to thiosulfate. Knockdown of the sulfur dioxygenase impaired embryo development and produced phenotypes of starvation-induced chlorosis during short-day growth conditions and extended darkness, indicating that ETHE1 has a key function in situations of high protein turnover, such as seed production and the use of amino acids as alternative respiratory substrates during carbohydrate starvation. The amino acid profile of mutant plants was similar to that caused by defects in the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase complex and associated dehydrogenases. Thus, in addition to sulfur amino acid catabolism, ETHE1 also affects the oxidation of branched-chain amino acids and lysine.

Benefits and harms of cervical screening from age 20 years compared with screening from age 25 years

BACKGROUND

To quantify the benefits (cancer prevention and down-staging) and harms (recall and excess treatment) of cervical screening starting from age 20 years rather than from age 25 years.

METHODS

We use routine screening and cancer incidence statistics from Wales (for screening from age 20 years) and England (screening from 25 years), and unpublished data from the National Audit of Invasive Cervical Cancer to estimate the number of: screening tests, women with abnormal results, referrals to colposcopy, women treated, and diagnoses of micro-invasive (stage 1A) and frank-invasive (stage IB+) cervical cancers (under three different scenarios) in women invited for screening from age 20 years and from 25 years.

RESULTS

Inviting 100,000 women from age 20 years yields an additional: 119,000 screens, 20,000 non-negative results, 8000 colposcopy referrals, and an extra 3000 women treated when compared with inviting from age 25 years. Screening from age 20 years prevents between three and nine frank invasive cancers and between 0 and 23 cancers in total (depending on the scenario). A cumulative increase of nine stage IB+ cancers corresponds to an annual rate increase of 0.9 per 100,000 women aged 20-29 years.

CONCLUSIONS

To prevent one frank invasive cancer, one would need to do between 12,500 and 40,000 additional screening tests in the age group 20-24 years and treat between 300 and 900 women.

Successful fertilization requires the presence of at least one major O-acetylserine(thiol)lyase for cysteine synthesis in pollen of Arabidopsis

The synthesis of cysteine (Cys) is a master control switch of plant primary metabolism that coordinates the flux of sulfur with carbon and nitrogen metabolism. In Arabidopsis (Arabidopsis thaliana), nine genes encode for O-acetylserine(thiol)lyase (OAS-TL)-like proteins, of which the major isoforms, OAS-TL A, OAS-TL B, and OAS-TL C, catalyze the formation of Cys by combining O-acetylserine and sulfide in the cytosol, the plastids, and the mitochondria, respectively. So far, the significance of individual OAS-TL-like enzymes is unresolved. Generation of all major OAS-TL double loss-of-function mutants in combination with radiolabeled tracer studies revealed that subcellular localization of OAS-TL proteins is more important for efficient Cys synthesis than total cellular OAS-TL activity in leaves. The absence of oastl triple embryos after targeted crosses indicated the exclusiveness of Cys synthesis by the three major OAS-TLs and ruled out alternative sulfur fixation by other OAS-TL-like proteins. Analyses of oastlABC pollen demonstrated that the presence of at least one functional OAS-TL isoform is essential for the proper function of the male gametophyte, although the synthesis of histidine, lysine, and tryptophan is dispensable in pollen. Comparisons of oastlABC pollen derived from genetically different parent plant combinations allowed us to separate distinct functions of Cys and glutathione in pollen and revealed an additional role of glutathione for pollen germination. In contrast, female gametogenesis was not affected by the absence of major OAS-TLs, indicating significant transport of Cys into the developing ovule from the mother plant.

A randomised trial of weekend and evening breast screening appointments

Background:

There is a need to research interventions that improve access to and convenience of breast cancer screening services.

Methods:

We conducted a randomised trial comparing invitations to out-of-hours appointments with standard office hour appointments. Women who were to be invited for routine breast screening were randomised (3 : 1 : 1 : 1) to one of these screening invitations: standard office hour appointment, office hour appointment with the option to change to an out-of-hours appointment, weekday evening appointment, or weekend appointment.

Results:

A total of 9410 women were invited to an office hour, 3519 to an office hour with the option to change, 3271 to a weekday evening, and 3162 to a weekend appointment. The offer of an initial out-of-hours appointment was associated with a non-significant decrease in attendance rates (73.7% vs 74.1%). The highest attendance was observed in the group offered an initial office hour appointment with the option to change to out-of-hours (76.1% vs 73.3% for standard office hour, P=0.001), with 7% of invitees exercising the option to change.

Conclusion:

The optimum strategy for improving attendance at breast screening is to offer a traditional office hour appointment and including in the letter of invitation an option to change to an evening or weekend appointment if wished.

The relevance of compartmentation for cysteine synthesis in phototrophic organisms

In the vascular plant Arabidopsis thaliana, synthesis of cysteine and its precursors O-acetylserine and sulfide is distributed between the cytosol, chloroplasts, and mitochondria. This compartmentation contributes to regulation of cysteine synthesis. In contrast to Arabidopsis, cysteine synthesis is exclusively restricted to chloroplasts in the unicellular green alga Chlamydomonas reinhardtii. Thus, the question arises, whether specification of compartmentation was driven by multicellularity and specified organs and tissues. The moss Physcomitrella patens colonizes land but is still characterized by a simple morphology compared to vascular plants. It was therefore used as model organism to study evolution of compartmented cysteine synthesis. The presence of O-acetylserine(thiol)lyase (OAS-TL) proteins, which catalyze the final step of cysteine synthesis, in different compartments was applied as criterion. Purification and characterization of native OAS-TL proteins demonstrated the presence of five OAS-TL protein species encoded by two genes in Physcomitrella. At least one of the gene products is dual targeted to plastids and cytosol, as shown by combination of GFP fusion localization studies, purification of chloroplasts, and identification of N termini from native proteins. The bulk of OAS-TL protein is targeted to plastids, whereas there is no evidence for a mitochondrial OAS-TL isoform and only a minor part of OAS-TL protein is localized in the cytosol. This demonstrates that subcellular diversification of cysteine synthesis is already initialized in Physcomitrella but appears to gain relevance later during evolution of vascular plants.

Structure and function of the hetero-oligomeric cysteine synthase complex in plants

Cysteine synthesis in bacteria and plants is catalyzed by serine acetyltransferase (SAT) and O-acetylserine (thiol)-lyase (OAS-TL), which form the hetero-oligomeric cysteine synthase complex (CSC). In plants, but not in bacteria, the CSC is assumed to control cellular sulfur homeostasis by reversible association of the subunits. Application of size exclusion chromatography, analytical ultracentrifugation, and isothermal titration calorimetry revealed a hexameric structure of mitochondrial SAT from Arabidopsis thaliana (AtSATm) and a 2:1 ratio of the OAS-TL dimer to the SAT hexamer in the CSC. Comparable results were obtained for the composition of the cytosolic SAT from A. thaliana (AtSATc) and the cytosolic SAT from Glycine max (Glyma16g03080, GmSATc) and their corresponding CSCs. The hexameric SAT structure is also supported by the calculated binding energies between SAT trimers. The interaction sites of dimers of AtSATm trimers are identified using peptide arrays. A negative Gibbs free energy (ΔG = -33 kcal mol(-1)) explains the spontaneous formation of the AtCSCs, whereas the measured SAT:OAS-TL affinity (K(D) = 30 nm) is 10 times weaker than that of bacterial CSCs. Free SAT from bacteria is >100-fold more sensitive to feedback inhibition by cysteine than AtSATm/c. The sensitivity of plant SATs to cysteine is further decreased by CSC formation, whereas the feedback inhibition of bacterial SAT by cysteine is not affected by CSC formation. The data demonstrate highly similar quaternary structures of the CSCs from bacteria and plants but emphasize differences with respect to the affinity of CSC formation (K(D)) and the regulation of cysteine sensitivity of SAT within the CSC.

Heat shock factors HsfB1 and HsfB2b are involved in the regulation of Pdf1.2 expression and pathogen resistance in Arabidopsis

In order to assess the functional roles of heat stress-induced class B-heat shock factors in Arabidopsis, we investigated T-DNA knockout mutants of AtHsfB1 and AtHsfB2b. Micorarray analysis of double knockout hsfB1/hsfB2b plants revealed as strong an up-regulation of the basal mRNA-levels of the defensin genes Pdf1.2a/b in mutant plants. The Pdf expression was further enhanced by jasmonic acid treatment or infection with the necrotrophic fungus Alternaria brassicicola. The single mutant hsfB2b and the double mutant hsfB1/B2b were significantly improved in disease resistance after A. brassicicola infection. There was no indication for a direct interaction of Hsf with the promoter of Pdf1.2, which is devoid of perfect HSE consensus Hsf-binding sequences. However, changes in the formation of late HsfA2-dependent HSE binding were detected in hsfB1/B2b plants. This suggests that HsfB1/B2b may interact with class A-Hsf in regulating the shut-off of the heat shock response. The identification of Pdf genes as targets of Hsf-dependent negative regulation is the first evidence for an interconnection of Hsf in the regulation of biotic and abiotic responses.

[The content of ascorbic acid in tissues of swine fetuses and newborn piglets and in the blood plasma and tissue of swine of different ages with regard to the effect of the restriction of suckling time]

In 55, 75, 95 and 110 days old pig-fetuses as well as in newborn piglets the weight of different tissues and their content of ascorbic acid were analysed. The time for suckling of the piglets of 2 sows was restricted to 12 hours per day (= group A); the piglets of 2 sows were used as a control (= group B). The restriction of the milk intake did not influence the content of the blood plasma and of the tissues in ascorbic acid. After weaning the pigs of group A had a compensatory growth and on the 214th day after birth the same slaughter mass as that of the group B. There was no difference in the content of ascorbic acid of the tissues of the 2 groups of pigs. The significance of changes in the content of ascorbic acid in the tissues during the fetal and the postnatal growth is described.

Trophic effects of different enteral diets in the rat intestine

The trophic effect of 4 commercial diets compared to chow was studied in 50 rats. The 4 commercial diets were: a free amino acid diet, a diet based on soy protein hydrolysate and two diets based on intact protein with and without extra fibre added. Bowel weight, mucosa weight and DNA content were measured after 7 days of treatment. The enteral formula based on a soy protein hydrolysate had a significant growth stimulating effect on the proximal small bowel compared to rat chow. In the ileum and in the colon all diets without fibre supplementation caused significantly lower bowel weights than rat chow.

Microcirculatory and trophic effects of short chain fatty acids in the human rectum after Hartmann's procedure

Short chain fatty acids (acetic, propionic and butyric) were instilled into the rectum of patients who had undergone Hartmann's procedure. The following parameters were examined before and after a 2-week treatment period with short chain fatty acids (100 ml twice daily at a total concentration of 150 mM): (1) microcirculatory effects in vivo using a laser Doppler flow technique, and (2) morphometrical changes in mucosal biopsies. The following parameters were significantly increased in all patients after treatment: (1) mucosal blood flow, (2) the fractional crypt cell epithelium plus surface epithelium volume in relation to total tissue volume down to the muscularis mucosa, (3) nuclear volume in the crypt and the surface epithelium, and (4) the fractional nuclear volume to total cell volume in the crypt and the surface epithelium. These data suggest that short chain fatty acids in the human colon have trophic and vasodilatory effects.

Treatment of ureteric colic. Intravenous versus rectal administration of indomethacin

A randomised multicentre clinical trial was undertaken to compare the effect on pain of indomethacin administered either intravenously or rectally to 116 patients with ureteric colic. Adverse reactions were also assessed. Of the patients receiving the intravenous injection, 48/53 (91%) achieved good pain relief (i.e. no supplementary analgesia was required) 30 min after administration, compared with 46/63 (73%) receiving the enema. Significantly more side effects occurred in the group treated intravenously. It was concluded that indomethacin administered as an enema was less effective than the intravenous form, but it should be regarded as a good alternative in the treatment of ureteric colic.

Fixation of displaced femoral neck fractures. A comparison between sliding screw plate and four cancellous bone screws

In a prospective, randomized trial, 104 consecutive patients with displaced femoral neck fractures were allocated either to fixation with a sliding screw plate or 4 ASIF cancellous bone screws. The patients were reexamined at fixed intervals to determine the time of union. The 2-year-cumulated rate of union was 64 per cent in the plate group and 84 per cent in the screw group.