CONSTANS, a HUB for all seasons: How photoperiod pervades plant physiology regulatory circuits

How does a plant detect the changing seasons and make important developmental decisions accordingly? How do they incorporate daylength information into their routine physiological processes? Photoperiodism, or the capacity to measure the daylength, is a crucial aspect of plant development that helps plants determine the best time of the year to make vital decisions, such as flowering. The protein CONSTANS (CO) constitutes the central regulator of this sensing mechanism, not only activating florigen production in the leaves but also participating in many physiological aspects in which seasonality is important. Recent discoveries place CO in the center of a gene network that can determine the length of the day and confer seasonal input to aspects of plant development and physiology as important as senescence, seed size, or circadian rhythms. In this review, we discuss the importance of CO protein structure, function, and evolutionary mechanisms that embryophytes have developed to incorporate annual information into their physiology.

Persulfidation protects from oxidative stress under nonphotorespiratory conditions in Arabidopsis

Hydrogen sulfide is a signaling molecule in plants that regulates essential biological processes through protein persulfidation. However, little is known about sulfide-mediated regulation in relation to photorespiration. Here, we performed label-free quantitative proteomic analysis and observed a high impact on protein persulfidation levels when plants grown under nonphotorespiratory conditions were transferred to air, with 98.7% of the identified proteins being more persulfidated under suppressed photorespiration. Interestingly, a higher level of reactive oxygen species (ROS) was detected under nonphotorespiratory conditions. Analysis of the effect of sulfide on aspects associated with non- or photorespiratory growth conditions has demonstrated that it protects plants grown under suppressed photorespiration. Thus, sulfide amends the imbalance of carbon/nitrogen and restores ATP levels to concentrations like those of air-grown plants; balances the high level of ROS in plants under nonphotorespiratory conditions to reach a cellular redox state similar to that in air-grown plants; and regulates stomatal closure, to decrease the high guard cell ROS levels and induce stomatal aperture. In this way, sulfide signals the CO₂ -dependent stomata movement, in the opposite direction of the established abscisic acid-dependent movement. Our findings suggest that the high persulfidation level under suppressed photorespiration reveals an essential role of sulfide signaling under these conditions.

Identification of reference genes for real-time PCR cytokine gene expression studies in sheep experimentally infected with Fasciola hepatica

The aim of this study was to validate reference genes for gene normalisation using qRT-PCR in hepatic lymph nodes (HLN) and livers from sheep infected with Fasciola hepatica during early and late stages of infection. To this end, a comprehensive statistical approach (RefFinder) encompassing four different methods of analysis (geNorm, BestKeeper, ΔCt method and NormFinder) was used to validate ten candidate reference genes. Stability analysis of gene expression followed by pairwise variation (Vn/Vn + 1) analysis revealed that PGK1, HSP90AA1 and GYPC were the most stable reference genes and suitable for qRT-PCR normalisation in both HLN and liver tissues. These three genes were validated against FoxP3, IL-10, TGF-β, TNF-α and IL-1β genes in the HLN tissue of sheep vaccinated with Cathepsin L1 from F. hepatica and unvaccinated infected and uninfected controls during early stages of infection. In the liver, the three reference genes were validated against TNF-α and IL-1β during chronic stages of infection with F. hepatica and in uninfected controls. Our study is the first to evaluate and validate sheep reference genes in order to provide tools for monitoring cytokines in Fasciola hepatica infected sheep target organs. Our results present an approach to elucidate the role of different cytokines in F. hepatica vaccinated and infected sheep.

Th1/Th2 balance in the liver and hepatic lymph nodes of vaccinated and unvaccinated sheep during acute stages of infection with Fasciola hepatica

The expression of IFNγ and IL4 was quantified using q-PCR in the liver and hepatic lymph nodes (HLN) of sheep during early stages of infection with Fasciola hepatica (1, 3, 9 and 18days post-infection, dpi). A group of animals (Group 1) were vaccinated with Fasciola hepatica recombinant cathepsin L1 (FhCL1) in montanide 70 VG prior to infection, a second group (group 2) was used as infected control and a third (group 3) was used as uninfected control. To study vaccine efficacy three additional groups were sacrificed 19 weeks post-infection (group 4 immunized with CL1, group 5 with the adjuvant and group 6 was used as infected control). The vaccinated group did not show significant fluke reduction compared to the adjuvant group and infected control group. IL4 expression was observed to increase at 9 dpi and was further elevated at 18 dpi in the liver and HLN of vaccinated and infected control groups compared to the uninfected group. IFNγ expression exhibited different dynamics in the liver and HLN compared to IL4; thus, in the liver this cytokine increased at 9 dpi in the vaccinated and at 18 dpi in vaccinated and infected control groups, while in the HLN it decreased gradually and significantly from 1 dpi onwards. These results suggest that a marked Th2 polarization is present from 9 dpi in HLN and from 18 dpi in the liver. The increase of IFNγ in the liver may correspond with tissue damage response with granuloma formation. The FhCL1 vaccine did not alter the Th1/Th2 balance when compared to unvaccinated and infected sheep. The study of IFNγ and IL4 in the various tissue compartments in sheep could facilitate selection of new adjuvants inducing a strong Th1 response for a more rationale vaccine formulation.

Apoptosis of peritoneal leucocytes during early stages of Fasciola hepatica infections in sheep

Several immunomodulatory properties have been described in Fasciola hepatica infections. Apoptosis has been shown to be an effective mechanism to avoid the immune response in helminth infections. The aim of the present work was to study apoptosis in peritoneal leucocytes of sheep experimentally infected with F. hepatica during the early stages of infection. Five groups (n=5) of sheep were used. Groups 2-5 were orally infected with 200 metacercariae (mc) and sacrificed at 1, 3, 9 and 18days post-infection (dpi), respectively. Group 1 was used as the uninfected control (UC). Apoptosis was detected using three different methods 1) immunocytochemistry (ICC) with a polyclonal antibody anti-active caspase-3; 2) an annexin V flow cytometry assay using the Annexin V-FITC/propidium iodide (PI); and 3) transmission electron microscopy (TEM). The differential leucocyte count revealed that the majority of peritoneal granulocytes were eosinophils, which increased significantly at 9 and 18 dpi with respect to the uninfected controls. The ICC study revealed that the percentage of caspase-3⁺ apoptotic peritoneal leucocytes increased significantly from 3 dpi onwards with respect to the uninfected controls. The flow cytometry annexin V assay detected a very significant (P<0.001) increase of apoptotic peritoneal macrophages, lymphocytes and granulocytes, which remained higher than in the UC until 18 dpi. Transmission electron microscopy studies also confirmed the presence of apoptosis in peritoneal eosinophils at 18 dpi. This is the first report of apoptosis induced by F. hepatica in the peritoneal leucocytes of sheep in vivo. The results of this work suggest the importance of apoptosis induction for the survival of the juvenile parasites in the peritoneal migratory stages of infection.

Evolution of Daily Gene Co-expression Patterns from Algae to Plants

Daily rhythms play a key role in transcriptome regulation in plants and microalgae orchestrating responses that, among other processes, anticipate light transitions that are essential for their metabolism and development. The recent accumulation of genome-wide transcriptomic data generated under alternating light:dark periods from plants and microalgae has made possible integrative and comparative analysis that could contribute to shed light on the evolution of daily rhythms in the green lineage. In this work, RNA-seq and microarray data generated over 24 h periods in different light regimes from the eudicot Arabidopsis thaliana and the microalgae Chlamydomonas reinhardtii and Ostreococcus tauri have been integrated and analyzed using gene co-expression networks. This analysis revealed a reduction in the size of the daily rhythmic transcriptome from around 90% in Ostreococcus, being heavily influenced by light transitions, to around 40% in Arabidopsis, where a certain independence from light transitions can be observed. A novel Multiple Bidirectional Best Hit (MBBH) algorithm was applied to associate single genes with a family of potential orthologues from evolutionary distant species. Gene duplication, amplification and divergence of rhythmic expression profiles seems to have played a central role in the evolution of gene families in the green lineage such as Pseudo Response Regulators (PRRs), CONSTANS-Likes (COLs), and DNA-binding with One Finger (DOFs). Gene clustering and functional enrichment have been used to identify groups of genes with similar rhythmic gene expression patterns. The comparison of gene clusters between species based on potential orthologous relationships has unveiled a low to moderate level of conservation of daily rhythmic expression patterns. However, a strikingly high conservation was found for the gene clusters exhibiting their highest and/or lowest expression value during the light transitions.

Characterization of the Sucrose Phosphate Phosphatase (SPP) Isoforms from Arabidopsis thaliana and Role of the S6PPc Domain in Dimerization

Sucrose-phosphate phosphatase (SPP) catalyses the final step in the sucrose biosynthesis pathway. Arabidopsis thaliana genome codifies four SPP isoforms. In this study, the four Arabidopsis thaliana genes coding for SPP isoforms have been cloned, expressed in Escherichia coli and the kinetic and regulatory properties of the purified enzymes analysed. SPP2 is the isoform showing the highest activity, with SPP3b and SPP3a showing lower activity levels. No activity was detected for SPP1. We propose that this lack of activity is probably due to the absence of an essential amino acid participating in catalysis and/or in the binding of the substrate, sucrose-6-phosphate (Suc6P). The expression patterns of Arabidopsis SPP genes indicate that SPP2 and SPP3b are the main isoforms expressed in different tissues and organs, although the non-catalytic SPP1 is the main isoform expressed in roots. Thus, SPP1 could have acquired new unknown functions. We also show that the three catalytically active SPPs from Arabidopsis are dimers. By generating a chimeric SPP composed of the monomeric cyanobacterial SPP fused to the higher plant non-catalytic S6PPc domain (from SPP2), we show that the S6PPc domain is responsible for SPP dimerization. This is the first experimental study on the functionality and gene expression pattern of all the SPPs from a single plant species.

Fasciola hepatica induces eosinophil apoptosis in the migratory and biliary stages of infection in sheep

The aim of the present work was to evaluate the number of apoptotic eosinophils in the livers of sheep experimentally infected with Fasciola hepatica during the migratory and biliary stages of infection. Four groups (n=5) of sheep were used; groups 1-3 were orally infected with 200 metacercariae (mc) and sacrificed at 8 and 28 days post-infection (dpi), and 17 weeks post-infection (wpi), respectively. Group 4 was used as an uninfected control. Apoptosis was detected using immunohistochemistry with a polyclonal antibody against anti-active caspase-3, and transmission electron microscopy (TEM). Eosinophils were identified using the Hansel stain in serial sections for caspase-3, and by ultrastructural features using TEM. At 8 and 28 dpi, numerous caspase-3(+) eosinophils were mainly found at the periphery of acute hepatic necrotic foci. The percentage of caspase -3(+) apoptotic eosinophils in the periphery of necrotic foci was high (46.1-53.9) at 8 and 28 dpi, respectively, and decreased in granulomas found at 28 dpi (6%). Transmission electron microscopy confirmed the presence of apoptotic eosinophils in hepatic lesions at 8 and 28 dpi. At 17 wpi, apoptotic eosinophils were detected in the infiltrate surrounding some enlarged bile ducts containing adult flukes. This is the first report of apoptosis induced by F. hepatica in sheep and the first study reporting apoptosis in eosinophils in hepatic inflammatory infiltrates in vivo. The high number of apoptotic eosinophils in acute necrotic tracts during the migratory and biliary stages of infection suggests that eosinophil apoptosis may play a role in F. hepatica survival during different stages of infection.

Photoperiodic control of carbon distribution during the floral transition in Arabidopsis

Flowering is a crucial process that demands substantial resources. Carbon metabolism must be coordinated with development through a control mechanism that optimizes fitness for any physiological need and growth stage of the plant. However, how sugar allocation is controlled during the floral transition is unknown. Recently, the role of a CONSTANS (CO) ortholog (Cr-CO) in the control of the photoperiod response in the green alga Chlamydomonas reinhardtii and its influence on starch metabolism was demonstrated. In this work, we show that transitory starch accumulation and glycan composition during the floral transition in Arabidopsis thaliana are regulated by photoperiod. Employing a multidisciplinary approach, we demonstrate a role for CO in regulating the level and timing of expression of the GRANULE BOUND STARCH SYNTHASE (GBSS) gene. Furthermore, we provide a detailed characterization of a GBSS mutant involved in transitory starch synthesis and analyze its flowering time phenotype in relation to its altered capacity to synthesize amylose and to modify the plant free sugar content. Photoperiod modification of starch homeostasis by CO may be crucial for increasing the sugar mobilization demanded by the floral transition. This finding contributes to our understanding of the flowering process.

5-Methyltetrahydrofolate-homocysteine methyltransferase gene polymorphism (MTR) and risk of head and neck cancer

The functional effect of the A>G transition at position 2756 on the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (HNSCC). The frequency of MTR A2756G (rs1805087) polymorphism was compared between HNSCC patients and individuals without history of neoplasias. The association of this polymorphism with clinical histopathological parameters was evaluated. A total of 705 individuals were included in the study. The polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. For statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. Using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. Multivariable analysis showed that tobacco and alcohol consumption (P < 0.05), AG genotype (P = 0.019) and G allele (P = 0.028) may be predictors of the disease and a higher frequency of the G polymorphic allele was detected in men with HNSCC compared to male controls (P = 0.008). The analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion, our data provide evidence that supports an association between the polymorphism and the risk of HNSCC.

The AtNHX1 exchanger mediates potassium compartmentation in vacuoles of transgenic tomato

NHX-type antiporters in the tonoplast have been reported to increase the salt tolerance of various plants species, and are thought to mediate the compartmentation of Na(+) in vacuoles. However, all isoforms characterized so far catalyze both Na(+)/H(+) and K(+)/H(+) exchange. Here, we show that AtNHX1 has a critical involvement in the subcellular partitioning of K(+), which in turn affects plant K(+) nutrition and Na(+) tolerance. Transgenic tomato plants overexpressing AtNHX1 had larger K(+) vacuolar pools in all growth conditions tested, but no consistent enhancement of Na(+) accumulation was observed under salt stress. Plants overexpressing AtNHX1 have a greater capacity to retain intracellular K(+) and to withstand salt-shock. Under K(+)-limiting conditions, greater K(+) compartmentation in the vacuole occurred at the expense of the cytosolic K(+) pool, which was lower in transgenic plants. This caused the early activation of the high-affinity K(+) uptake system, enhanced K(+) uptake by roots, and increased the K(+) content in plant tissues and the xylem sap of transformed plants. Our results strongly suggest that NHX proteins are likely candidates for the H(+)-linked K(+) transport that is thought to facilitate active K(+) uptake at the tonoplast, and the partitioning of K(+) between vacuole and cytosol.

Setting the stage for school health-promoting programmes for deaf children in Spain

Implementing health-promoting programmes for the most excluded and at-risk social groups forms a key part of any efforts to address underserved populations and reduce health inequalities in society. However, many at-risk children, particularly children in deaf communities, are not reached, or are poorly served, by health-promoting programmes within the school setting. This is so because schools are effective as health-promoting environments for d/Deaf children only to the extent that they properly address their unique communication needs and ensure they are both able and enabled to learn in a communication-rich and supportive psycho-social environment. This article examines how the usually separate strands of school health promotion and d/Deaf education might be woven together and illustrates research with deaf community members that involves them and gives their perspective. The primary objective of this study was to map deaf pilot bilingual education programmes in Spain-one of the first countries to ratify the Convention on the Rights of Persons with Disabilities (United Nations. (2006) Convention on the Rights of Persons with Disabilities, Resolution A/RES/61/106.)-with particular attention to their compliance to the Convention's article 24. Following pre-testing, 516 key informants were surveyed by mail (response rate: 42.08%) by using a snow-ball key-informant approach, within a Participatory Action Research framework, at a national, regional and local level. The results show that although some schools have achieved recommended standards, bilingual programmes are in various stages of formulation and implementation and are far from being equally distributed across the country, with only four regions concentrating more than 70% of these practices. This uneven geographical distribution of programmes probably reflects more basic differences in the priority given by regions, provinces, and municipalities to the deaf community's needs and rights as an important policy objective and may reinforce or widen inequalities by favouring or discriminating rather than achieving access and equity for this noticeably overlooked community.

Purification and identification of the pediocin produced by Pediococcus acidilactici MM33, a new human intestinal strain

AIMS

The aim of this study was to purify and identify the bacteriocin produced by Pediococcus acidilactici MM33, a strain previously isolated from human gut.

METHODS AND RESULTS

Purification of the bacteriocin was performed by cationic exchange chromatography followed by a reverse phase step. Biochemical and mass spectrometry analysis showed homology with pediocin PA-1. To verify if P. acidilactici MM33 carried the pediocin PA-1 gene, total DNA was used to amplify the pediocin gene. The PCR product obtained was then sequenced and the nucleotide sequence revealed to be identical to that of pediocin PA-1. Treatment of P. acidilactici MM33 with novobiocin resulted in a plasmid-cured strain without bacteriocin-producing capacity. Antimicrobial assay and molecular analysis demonstrated that this strain was ped(-) suggesting that the ped cluster is plasmid encoded. Antimicrobial assay revealed that pediocin was bactericidal against Listeria monocytogenes, showing a minimal inhibitory concentration (MIC) of 200 AU ml(-1).

CONCLUSIONS

A two-step purification procedure was elaborated in this study. The bacteriocin secreted by the human strain P. acidilactici MM33 is carried on a plasmid and the amino acid sequence is identical to pediocin PA-1.

SIGNIFICANCE AND IMPACT OF THE STUDY

Pediococcus acidilactici MM33 is the first human pediocin-producing strain reported and could be used as probiotic to prevent enteric pathogen colonization.

Copy number of P elements, KP/full-sized P element ratio and their relationships with environmental factors in Brazilian Drosophila melanogaster populations

The P transposable element copy numbers and the KP/full-sized P element ratios were determined in eight Brazilian strains of Drosophila melanogaster. Strains from tropical regions showed lower overall P element copy numbers than did strains from temperate regions. Variable numbers of full-sized and defective elements were detected, but the full-sized P and KP elements were the predominant classes of elements in all strains. The full-sized P and KP element ratios were calculated and compared with latitude. The northernmost and southernmost Brazilian strains showed fewer full-sized elements than KP elements per genome, and the strains from less extreme latitudes had many more full-sized P than KP elements. However, no clinal variation was observed. Strains from different localities, previously classified as having P cytotype, displayed a higher or a lower proportion of KP elements than of full-sized P elements, as well as an equal number of the two element types, showing that the same phenotype may be produced by different underlying genomic components of the P-M system.

Transient expression of Arabidopsis thaliana ascorbate peroxidase 3 in Nicotiana benthamiana plants infected with recombinant potato virus X

We have explored the transient over-expression of Arabidopsis thaliana ascorbate peroxidase 3 (APX3) in Nicotiana benthamiana using a viral vector based on the potato virus X (PVX). Plants infected with a PVX:APX3 hybrid had a similar progression of viral particles compared to control plants infected with a PVX:GFP hybrid, indicating that infection was not affected by the over-expression of heterologous APX3. Our results also showed that in PVX:APX3-infected plants, the hybrid virus directed a high level of APX3 expression and the recombinant protein was functional, as inferred from the higher APX activity compared to mock and PVX:GFP hybrid-infected plants. The PVX recombinant expression system used is a simple and quick method for transient expression of heterologous APXs, which are expected to suffer specific processing in plant cells.

[Control of Chagas' disease in Guarani communities: knowledge and hygiene habits within the Project to Improve Living Conditions in Bolivia]

The aim of this study was to identify knowledge and control of vectorial transmission (Triatoma infestans, known as vinchuca) of Chagas' disease in Guaraní Communities in Bolivia. We performed a descriptive study of a series of 98 individuals through a semi-structured questionnaire. Interviewees were asked about their familiarity with vinchuca, whether they thought vinchuca produced disease, the name of the disease and its consequences, as well as behavior related to eliminating the domestic insect vectors, such as cleaning of the home, backyard and corral.The insect vector was sufficiently well known (98%), although the name of the disease was identified by only 14.3% of the interviewees. Although the dwellings favored insect proliferation, they were not frequently cleaned: 28.6% cleaned their homes while and 42.9% cleaned the backyard and 7.1% cleaned the corral. Gender differences were found in the division of labor: women cleaned the homes and backyards, while men clean the corral. Experience has shown that the usefulness of projects for building healthy living areas and for health education depends on the value given to these projects by the community. Women are probably the best target group, because they perform a greater number of preventive tasks and seldom leave the community for extended periods of time.

Doing things together: adolescent health and family rituals

STUDY OBJECTIVES

(1) To describe the union and life cycle of family rituals, such as specific habits of sharing daily meals, special events or other family activities, and (2) to analyse the relation between the practice of family rituals and the use by adolescents of mental health related ambulatory care services.

DESIGN

A cross sectional study.

SETTING

A public mental health care outpatient clinic, secondary educational centres and Alicante University (School of Social Workers and Nursing School) in Spain.

PARTICIPANTS

A total of 282 living at home youngsters were included in the study. The case group, n=82, was sequential and consecutively drawn from the first consultation in a public mental health outpatient clinic attending a downtown area of Alicante. The comparison group (n=213) was made up of a conglomerate from various educational centres in the same metropolitan area.

MAIN RESULTS

There was a significant difference (p=0.027) between the frequencies with which parents ate together with their offspring in the two study groups. The families of the adolescents comparison group significantly (p=0.00007) shared more family celebrations than the case group-also, the extended family was included more frequently. Moreover, differences between both groups were found in other activities and situations-adolescents in the case group reported carrying out less family activities than the adolescents in the comparison group (p=0.00001). The lower level of satisfaction in the adolescent's perception of family function led to a higher probability of presenting mental health complaints (p=0.00001).

CONCLUSIONS

The youngsters with mental health complaints ate less frequently with both parents than the youngsters in the comparison group. They also shared less activities and practised less family rituals-union and life cycle-than the families of the youngsters in the comparison group, and showed a lower level of satisfaction in perceived family function.

The widening social class gap of preventive health behaviours in Spain

As a way of forecasting future evolution of inequalities in disease burden and mortality, trends in preventive health behaviours by social class were examined. Using the Spanish National Health Survey from 1987 to 1997 the evolution of the Health Practices Index (smoking, alcohol consumption, physical exercise, sleep hours and the Quetelet index) is described for the Spanish non-institutionalised adult population. In the last 10 years the disadvantaged population of Spain (social class groups IV and V) has not opted for healthier behavioural choices. On the contrary the Health Practices Index figures have worsened during the study period. Conversely, the more affluent groups (social class groups I, II and III) have exhibited a net gain in the index. Due to this, an increase in the existing gap in health inequalities in Spain in terms of morbidity and mortality can be forecast for the near future. As time trends of a summary indicator of preventive health behaviours by social class have not been described in other countries, a replication of this study in different cultural, social and economic milieus could produce valuable information.

Empowering the deaf. Let the deaf be deaf

Deafness is often regarded as just a one and only phenomenon. Accordingly, deaf people are pictured as a unified body of people who share a single problem. From a medical point of view, we find it usual to work with a classification of deafness in which pathologies attributable to an inner ear disorder are segregated from pathologies attributable to an outer/middle ear disorder. Medical intervention is thus concerned more with the origin, degree, type of loss, onset, and structural pathology of deafness than with communicative disability and the implications there may be for the patient (mainly dependency, denial of abnormal hearing behaviour, low self esteem, rejection of the prosthetic help, and the breakdown of social relationships). In this paper, we argue that hearing loss is a very complex phenomenon, which has many and serious consequences for people and involves many factors and issues that should be carefully examined. The immediate consequence of deafness is a breakdown in communication whereby the communicative function needs to be either initiated or restored. In that sense, empowering strategies--aimed at promoting not only a more traditional psychological empowerment but also a community one--should primarily focus on the removal of communication barriers.

OBA/Ku86: DNA binding specificity and involvement in mammalian DNA replication

Ors-binding activity (OBA) was previously semipurified from HeLa cells through its ability to interact specifically with the 186-basepair (bp) minimal replication origin of ors8 and support ors8 replication in vitro. Here, through competition band-shift analyses, using as competitors various subfragments of the 186-bp minimal ori, we identified an internal region of 59 bp that competed for OBA binding as efficiently as the full 186-bp fragment. The 59-bp fragment has homology to a 36-bp sequence (A3/4) generated by comparing various mammalian replication origins, including the ors. A3/4 is, by itself, capable of competing most efficiently for OBA binding to the 186-bp fragment. Band-shift elution of the A3/4-OBA complex, followed by Southwestern analysis using the A3/4 sequence as probe, revealed a major band of approximately 92 kDa involved in the DNA binding activity of OBA. Microsequencing analysis revealed that the 92-kDa polypeptide is identical to the 86-kDa subunit of human Ku antigen. The affinity-purified OBA fraction obtained using an A3/4 affinity column also contained the 70-kDa subunit of Ku and the DNA-dependent protein kinase catalytic subunit. In vitro DNA replication experiments in the presence of A3/4 oligonucleotide or anti-Ku70 and anti-Ku86 antibodies implicate Ku in mammalian DNA replication.

An EXCEL template for calculation of enzyme kinetic parameters by non-linear regression

MOTIVATION

An EXCEL template has been developed for the calculation of enzyme kinetic parameters by non-linear regression techniques. The tool is accurate, inexpensive, as well as easy to use and modify.

AVAILABILITY

The program is available from http://www.ebi.ac.uk/biocat/biocat.html

CONTACT

agustin. hernandez@bio.kuleuven.ac.be

Initiation and maintenance of virus-induced gene silencing

The phytoene desaturase (PDS) gene of Nicotiana benthamiana was silenced in plants infected with potato virus X (PVX) vectors carrying PDS inserts, and a green fluorescent protein (GFP) transgene was silenced in plants infected with PVX-GFP. This virus-induced gene silencing (VIGS) is post-transcriptional and cytoplasmic because it is targeted against exons rather than introns of PDS RNA and against viral RNAs. Although PDS and GFP RNAs are most likely targeted through the same mechanism, the VIGS phenotypes differed in two respects. PDS mRNA was targeted by VIGS in all green tissue of the PVX-PDS-infected plant, whereas PVX-PDS was not affected. In contrast, VIGS of the GFP was targeted against PVX-GFP. Initially, VIGS of the GFP was initiated in all green tissues, as occurred with PDS VIGS. However, after 30 days of infection, the GFP VIGS was no longer initiated in newly emerging leaves, although it was maintained in tissue in which it had already been initiated. Based on these analyses, we propose a model for VIGS in which the initiation of VIGS is dependent on the virus and maintenance of it is virus independent.

Initiation and maintenance of virus-induced gene silencing

The phytoene desaturase (PDS) gene of Nicotiana benthamiana was silenced in plants infected with potato virus X (PVX) vectors carrying PDS inserts, and a green fluorescent protein (GFP) transgene was silenced in plants infected with PVX-GFP. This virus-induced gene silencing (VIGS) is post-transcriptional and cytoplasmic because it is targeted against exons rather than introns of PDS RNA and against viral RNAs. Although PDS and GFP RNAs are most likely targeted through the same mechanism, the VIGS phenotypes differed in two respects. PDS mRNA was targeted by VIGS in all green tissue of the PVX-PDS-infected plant, whereas PVX-PDS was not affected. In contrast, VIGS of the GFP was targeted against PVX-GFP. Initially, VIGS of the GFP was initiated in all green tissues, as occurred with PDS VIGS. However, after 30 days of infection, the GFP VIGS was no longer initiated in newly emerging leaves, although it was maintained in tissue in which it had already been initiated. Based on these analyses, we propose a model for VIGS in which the initiation of VIGS is dependent on the virus and maintenance of it is virus independent.

Oct-1 enhances the in vitro replication of a mammalian autonomously replicating DNA sequence

A 186-base pair fragment of ors8, a mammalian autonomously replicating DNA sequence isolated by extrusion of nascent monkey DNA in early S phase, has previously been identified as the minimal sequence required for replication function in vitro and in vivo. This 186-base pair fragment contains, among other sequence characteristics, an imperfect consensus binding site for the ubiquitous transcription factor Oct-1. We have investigated the role of Oct-1 protein in the in vitro replication of this mammalian origin. Depletion of the endogenous Oct-1 protein, by inclusion of an oligonucleotide comprising the Oct-1 binding site,inhibited the in vitro replication of p186 to approximately 15-20% of the control, whereas a mutated Oct-1 and a nonspecific oligonucleotide had no effect. Furthermore, immunodepletion of the Oct-1 protein from the HeLa cell extracts by addition of an anti-POU antibody to the in vitro replication reactioninhibited p186 replication to 25% of control levels. This inhibition of replication could be partially reversed to 50-65% of control levels, a two- to threefold increase, upon the addition of exogenous Oct-1 POU domain protein. Site-directed mutagenesis of the octamer binding site in p186 resulted in a mutant clone, p186-MutOct, which abolished Oct-1 binding but was still able to replicate as efficiently as the wild-type p186. The results suggest that Oct-1 protein is an enhancing component in the in vitro replication of p186 but that its effect on replication is not caused through direct binding to the octamer motif.

Posttranslational regulation of nitrogenase activity by fixed nitrogen in Azotobacter chroococcum

Using anti-(Fe protein) antibody raised against the Fe protein of the photosynthetic bacterium Rhodospirillum rubrum, it was found that the Fe protein component of nitrogenase (EC 1.18.2.1) from Azotobacter chroococcum cells subjected to an ammonium shock, and hence with an inactive nitrogenase, appeared as a doublet in Western blot analysis of cell extracts. The Fe protein incorporated [32P]phosphate and [3H]adenine in response to ammonium treatment, and L-methionine-DL-sulfoximine, an inhibitor of glutamine synthetase (L-glutamate: ammonia ligase (ADP forming), EC 6.3.1.2), prevented Fe protein from inhibition and radioisotope labelling. These results support that A. chroococcum Fe protein is most likely ADP-ribosylated in response to ammonium. After ammonium treatment, when in vivo activity was completely inhibited, Fe-protein modification was still increasing. This suggests the existence of another mechanism of nitrogenase inhibition faster than Fe-protein modification. When ammonium was intracellularly generated instead of being externally added, as occurs with the short-term nitrate inhibition of nitrogenase activity observed in A. chroococcum cells simultaneously fixing molecular nitrogen and assimilating nitrate, a covalent modification of the Fe protein was likewise demonstrated.

[Sexual myths in an adult population]

BACKGROUND

Clinical observation ratifies the existence of commonly accepted erroneous beliefs (EB) in relation to sexuality. In the health care sector, reinforcing factors of these beliefs are the professionals who are not specifically trained to manage, or detect the same in addition to the variability of the criteria available on sexual health care.

METHODS

The EB on sexuality were studied in 260 individuals (14-18 years) who are users of primary health care services. Four consultation offices of General Medicine were randomly selected, one by health care center (Area 20, Valencian Community, Spain). Subsequently, a structured interview was given to the users of these consultations over the period of one day. The interviews were carried out after receiving consent and guarantee of confidentiality. On the other hand, the results were compared with those previously obtained from the 44 health care professionals (HCP). The results are reported, the proportions compared (chi-square) to determine differences according to age, sex and level of education and the odds ratio was calculated to determine the probability of participation in EB according to sex. The response rate in users was 97.4% and is HCP 58%.

RESULTS

The proportion of EB ranged from 16.9% who believed coitus as the only "normal" sexual relationship and 63.8% who believed in the existence of two types of female orgasm. Depending on the beliefs, statistically significant differences were observed according to age (from p = 0.03 to p < 0.0000) and the level of education (from p = 0.01 to p < 0.0000) and between the user adult population and the HCP (from p = 0.01 to p < 0.0000).

CONCLUSIONS

There are numerous erroneous beliefs regarding sexuality in both primary health care users and, to a lesser extent, Spanish health care professionals. The influence of moral criteria, centered on reproduction, and prevalent sociocultural norms and values is of note. It was found that erroneous beliefs do not decrease with the educational level, but rather, change.

Cofractionation of HeLa cell replication proteins with ors-binding activity

Ors (origin enriched sequence) 8 is a mammalian autonomously replicating DNA sequence previously isolated by extrusion of nascent monkey (CV-1) DNA in early S phase. A 186 bp fragment of ors 8 has been identified as the minimal sequence required for origin function, since upon its deletion the in vivo and in vitro replication activity of this ors is abolished. We have fractionated total HeLa cell extracts on a DEAE-Sephadex and then on a Affi-Gel Heparin column and identified a protein fraction that interacts with the 186 bp fragment of ors 8 in a specific manner. The same fraction is able to support the in vitro replication of ors 8 plasmid. The ors binding activity (OBA) present in this fraction sediments at approximately 150 kDa in a glycerol gradient. Band-shift elution experiments of the specific protein-DNA complex detect by silver-staining predominantly two protein bands with molecular weights of 146 kDa and 154 kDa, respectively. The fraction containing the OBA is also enriched for polymerases alpha and delta, topoisomerase II, and replication protein A, (RP-A).

Reliability of the diagnosis of rheumatic conditions at the primary health care level

OBJECTIVE

To assess the reliability of the diagnosis given to rheumatic disease patients at the primary care level, the clinical records of 612 patients at the outpatient clinic of rheumatology of the main General Hospital in Alicante (Spain) were studied.

METHODS

The accuracy indices (sensitivity, specificity), the predictive values of tentative diagnosis made by the referring physicians and the degree of agreement (Kappa statistics) with the final diagnoses made by rheumatologists at the outpatient clinic of rheumatology were calculated.

RESULTS

There were differences in diagnosis agreement depending on the age of the referring doctor, with a greater degree of concordance among younger ones. More than 50% of the referral diagnoses were modified at the rheumatology outpatient clinic. In the most frequent diagnoses (inflammatory rheumatic diseases, osteoarthritis, soft tissue rheumatism) the level of concordance and the predictive values were low.

CONCLUSION

Our results highlight the need for upgrading courses in rheumatology for primary care physicians who have not been exposed to systematic training in rheumatology during their undergraduate studies. The epidemiological studies on rheumatic diseases based on primary care data should be interpreted with caution.

Cruciform DNA binding protein in HeLa cell extracts

We have analyzed by band-shift assays HeLa cell protein-DNA interactions on a stable cruciform DNA molecule. The stable cruciform was formed by heteroduplexing the HindIII-SphI fragment of SV40 virus DNA that contains the origin of replication with a derivative mutant containing a heterologous substitution at the central inverted repeat. We have identified a novel binding activity in HeLa cell extracts with specificity for the cruciform-containing DNA and no apparent sequence specificity. The activity is protein-dependent, void of detectable nuclease activity, and distinct from that reported for HMG1. A cruciform binding protein (CBP) with an apparent molecular weight of 66 kDa was enriched from HeLa cell extracts. In addition to the CBP, we have detected sequence-specific binding activities to sites proximal to the cruciform. Binding to one such site is increased in the cruciform-containing heteroduplex DNA by comparison to its linear homoduplex counterpart, suggesting transmission of structural effects by the stem-loops to their local environment.

[Disturbances in sexual function: analysis of conditioning factors of an effective health care center]

BACKGROUND

With the aim of promoting activities related with sexual problems of the population in the health care area of the province of Alicante (Spain), the following objectives were set to the teams of primary health care: to know the opinion of the professionals concerning the most frequent reasons for consultation related with sexuality, establish opinions on their knowledge and educational requirements in this area, decrease sexual myths, strengthen the habit of registration of information on sexual behavior and problems related with the sexuality of the users and increase the frequency of derivating these problems to specialists.

METHODS

Information was collected with a self applied survey on variables related with the above objectives. Four seminars were then developed on human sexual response, sexologic interview, sexual dysfunction and sexual therapy from the results obtained. One year thereafter, an evaluation was carried out in which the initial survey was reapplied.

RESULTS

Fifty-eight percent of the 77 primary care professionals responded to the survey adequately in the initial phase. In their opinion the first three causes for consultation are impotence (13%), dispareunia (12%) and sexual disturbances related with chronic diseases (11%). The perception of their knowledge concerning the subjects covered in the seminars was slight with training in this area being clearly required. Eighty-nine percent were in favor of the collection of information on sexuality in health care files in contrast to 20% who reported to do so. From the initial to the final evaluation a decrease was seen in the direct intervention of the primary health care teams and an increase in derivations to specialists, which was of interest since around 20% of the professionals have erroneous beliefs on sexuality, varying according to the professions.

CONCLUSIONS

The low level of knowledge and abilities perceived, the need for education, possession of the erroneous beliefs of the health care professionals surveyed and the passive behavior but positive attitude towards the sexual problems of the population reconfirm the importance of adequate continued training to health care professionals, particularly to those of primary health care since they are the ideal suppliers of assistance to sexual problems.

Thomas McKeown and Archibald Cochrane: a journey through the diffusion of their ideas

In the 1970s Thomas McKeown and Archibald L Cochrane were two of the most influential voices in criticizing the dominance of medical thinking. A bibliometric study of the citations to McKeown's The Role of Medicine: Dream, Mirage or Nemesis and Cochrane's Effectiveness and Efficiency: Random Reflections on Health Services was performed from the publication of each book until 1988 to study how their ideas have been disseminated. During the study period 430 papers in the Science Citation Index or the Social Sciences Citation Index cited Cochrane's book, 133 cited McKeown's, and 166 cited both. The citations came mainly from original papers published in journals of internal medicine or public health and epidemiology (35%) and written by authors from the United States or the United Kingdom. Cochrane's book was cited most frequently in medical journals, suggesting a higher degree of penetration of his ideas among medical scientists. Although the dominance of original papers among the citations suggests that these books have been important in stimulating new knowledge, the main problems that McKeown and Cochrane identified--namely, the relatively small impact of clinical medicine on health outcomes and the poor use of scientific methods in clinical practice--are still with us.

[Undergraduate training in primary health care: 6 years' experience at the University of Alicante]

OBJECTIVE

To assess the opinion of medical students on the teaching offered in the Primary Care context (TOPC).

DESIGN

Observational and crossover study. The assessment used an opinion questionnaire.

PARTICIPANTS

296 sixth-year medical students between 1987 and 1992.

INTERVENTIONS

The TOPC consisted of four weeks stay in a Health Centre with an eminently practical programme. However this also included hour-long theoretical seminars on the most important Primary Care questions and the student's completion of a research project related to Primary Care.

RESULTS

The students expressed satisfaction with the TOPC (average score of 4 out of 5). Moreover this satisfaction increased over the five years (from 3.7 to 4.6, p = 0.0001). They believed the TOPC to be useful (3.6 to 4.7, p = 0.0001) and relevant to their future professional activity (3.1 to 4.6, p = 0.0001). They thought that the tutors were very competent (4 out of 5, with no significant variation) and the Health Centres' teaching facilities suitable (3.8 to 4, with no significant variation). Finally, they considered that TOPC should become a compulsory undergraduate subject (3.9 out of 5).

CONCLUSIONS

Medical students give a positive rating to the Primary Care teaching offered and believe it should be integrated into the Medicine syllabus as a compulsory subject.

A simplified histoscore for the estrogen receptor assay in breast cancer

Different histoscores combining the number of positive cells and the intensity of staining have been used to evaluate the estrogen receptor immunocytochemical assay (ER-ICA). Our aim was to investigate if the simple estimation of the amount of positive cells could be sufficient for the semiquantitative analysis of ER-ICA. Tissue from 51 women with ductal breast carcinoma was used. Half of each sample was processed with the quantitative assay (ER-EIA) and the other half with ER-ICA. Microscopical analysis was performed by two independent observers and classified on a simple scale from 0 to 4+. With EIA 31 cases (60.78%) were positive and 20 (39.21%) negative. With ER-ICA 29 (56.86%) had immunostaining, whereas 22 (43.13%) did not. 95.83% of the ER-ICA positive cases and 77.7% of ER-ICA negative had a good correlation with EIA values. Statistical analysis showed a high degree of correlation (r = 0.88 p 0.001). Hence, simple semiquantitative estimation in ER-ICA is sufficient to provide useful information for clinical use about ER content in tissue sections.

Study designs and statistical methods in rheumatological journals: an international comparison

In order to determine the characteristics of papers published in the rheumatological literature, we have conducted a survey of the seven leading rheumatological journals published in 1987; 1107 original papers have been reviewed and classified according to study design, statistical techniques, and country of origin. Almost half of the published papers were clinical descriptive studies without inferential power; both authors and editors should reflect whether the impact of these studies on the knowledge of readers justifies their frequency. Analytical research was represented mainly by randomized clinical trials (15.6%), and case control studies (14.2%). Cohort studies represented 5.4% and this seems a low figure in a specialty in need of more aetiological research. Almost half of the papers originated from the USA or the UK; journals edited in these countries published papers mainly from the same country. English language journals from other countries published a larger percentage of papers from other countries, including many non-English speaking nations. Bibliometric studies are desirable to evaluate trends in publication.

[Opinion of medical students about prescription, counseling and practice of voluntary interruptions of pregnancy]

BACKGROUND

A future prospect was carried out of the professional trends regarding prescription, counseling and practice of voluntary interruptions of pregnancy (VIP).

METHODS

To this end, a questionnaire was administered to 177 last term students of the Valencia and Alicante Schools of Medicine regarding the opinions of the current law on VIP in Spain and the professional trends of approach, with practical examples of the four instances depenalized by the Spanish law.

RESULTS

For 44% of the sample the present law is insufficient, 30% agree with it and 13% think that the present law threatens life. The instance which elicited a highest number of favorable professional trends was congenital malformation (85%), followed by physical problems (78%) and psychical problems (63%). Only 60% of students would take a favorable attitude in case of rape. The students without religious practice, who vote progressive political parties and who think that present law is insufficient have a significant tendency towards attitudes favoring VIP. Significant sex differences among students were not found.

CONCLUSIONS

Although probably to a lesser degree than in the present, in the near future the unfavorable attitudes of physicians will continue hindering the access of women to the services of VIP. A wide debate and more studies are required for a better definition of the implications of this phenomenon for public health purposes.

Higher incidence of carpal tunnel syndrome in oophorectomized women

To determine whether the hormonal changes of the menopause are related to the onset of carpal tunnel syndrome (CTS), 53 healthy women, younger than 44 years, and subjected to bilateral oophorectomy between 1 and 4 years before the study, were evaluated. Seventy healthy menstruating women matched for age were used as controls. In those complaining of symptoms and presenting signs suggestive of CTS, sensory and motor nerve conduction studies were done. In the oophorectomized group, 17 of 53 (32%) had clinical CTS, while only seven of 70 of the control group (10%) did so (relative risk for the oophorectomized group = 4.25; 95% confidence intervals 1.47 and 12.61). The nerve conduction studies were abnormal in 14 of 16 oophorectomized women (87.5%), and in only one of seven of the control group (14.2%; P less than 0.002). Symptoms tended to be milder in the controls. Symptoms developed in the first year after oophorectomy in 14 of the 17 women with CTS. This suggests that women develop CTS after oophorectomy more frequently than controls.

Evaluation of a simple semiquantitative assay for estrogen receptors in breast cancer

A number of studies have been published to evaluate the inmunocytochemical assay for ER using monoclonal antibodies. Histoscores so far used consider two variables: the number of cells and the intensity of the reaction. There are however indications that only the proportion of stained cells are important for assessment and show a direct correlation with quantitative data. We studied 77 breast invasive adenocarcinomas stained with the Abbott ERICA kit and used a simple scale of 0 to 4 for the estimation of ER. Tissues were snap frozen in liquid N and immunostained with the specific antibody and peroxidase. Immunostaining was estimated in a simple observational scale from 0-4+ where 0 = no staining or few scattered positive cells; 1+ up to 25%; 2+ up to 50%; 3+ up to 75% and 4+ more than 75% of stained malignant cells. Counts were performed in at least 100 malignant cells in various microscopic fields. Staining was always nuclear and a considerable heterogeneity in the number of cells and the intensity of the reaction was observed. Grading specimens from 0-4+ was found simple and reproducible. In 45% there was no immunostaining and 54% were positive for ER. In patients greater than 50 years of age 67% were positive; in patients less than 50 years of age only 33% had ER. This procedure has many advantages for clinical use: it is simple, it does not require sophisticated equipment, it is reproducible and can be performed in small tissue fragments, such as needle aspiration material, as well as in cytological smears.

[Rheumatology research. An analysis of the situation in Spain]

To analyze the present status of rheumatological research in Spain, three indicators have been evaluated: use of the different study designs, use of statistical techniques and relevance of the studies. This last point was determined by the comparison of the research areas that had been reported during one year and the lines of rheumatological research established as priorities by 10 investigators from the 10 units of clinical care with a higher scientific output during the period 1985-1987. A revision has been made of the 67 articles from Spain out of the 1106 reported in seven of the journals with a better national and international impact index: Scandinavian Journal of Rheumatology, Arthritis and Rheumatism, Journal of Rheumatology, Annals of the Rheumatic Diseases, British Journal of Rheumatology, Clinical Experimental Rheumatology and Revue du Rhumatisme, in addition to Revista Española de Reumatología. It was found that few studies with analytical design are being published and that complex statistical analysis techniques are not being used; therefore, most articles do not have a possible statistical inference and lack value as predictors. The reports of cases and clinical series in the Letters to the Editor section are most common, particularly in the Spanish journal. Most studies are related with clinical research, although the consulted investigators consider that basic and epidemiological research have a higher priority. It is concluded that the Spanish contribution to the international rheumatological literature is still small and has a mainly descriptive character; thus, it is necessary to emphasize the use of analytical designs to improve the competitiveness. The type of studies to be carried out in the future, according to the priorities established by the investigators themselves, should change if their wishes are to be fulfilled.

The ordinary light microscope: an appropriate tool for provisional detection and identification of crystals in synovial fluid

To determine if the ordinary light microscope is a useful tool in the detection and identification of crystals in synovial fluid 63 fluids (13 with monosodium urate (MSU), 14 with calcium pyrophosphate dihydrate (CPPD), one with both types of crystal, and 35 without crystals) were examined blindly by two observers, first with an ordinary light microscope, then with a polarising light microscope. Tentative identification of the crystals by their shape was attempted. The sensitivity of the ordinary light microscope for the detection of crystals was 96.2% and 100%, with specificity of 100% and 97.1% for observers 1 and 2, both with respect to the polarising light microscope. The concordance between observers for the ordinary light microscope was chi = 0.90 (0.897, 0.902) and for the polarising light microscope chi = 0.96 (0.958, 0.961). The specificity for identification of MSU and CPPD crystals by their shape with respect to the polarising light microscope was 92.3% and 85.7% for observers 1 and 2. When a polarising light microscope is not available examination of synovial fluid by an ordinary light microscope may allow a provisional diagnosis; definitive identification of the crystals requires a polarising light microscope.