Genetic mapping of a major dominant gene for resistance to Ralstonia solanacearum in eggplant.

Resistance of eggplant against Ralstonia solanacearum phylotype I strains was assessed in a F(6) population of recombinant inbred lines (RILs) derived from a intra-specific cross between S. melongena MM738 (susceptible) and AG91-25 (resistant). Resistance traits were determined as disease score, percentage of wilted plants, and stem-based bacterial colonization index, as assessed in greenhouse experiments conducted in Réunion Island, France. The AG91-25 resistance was highly efficient toward strains CMR134, PSS366 and GMI1000, but only partial toward the highly virulent strain PSS4. The partial resistance found against PSS4 was overcome under high inoculation pressure, with heritability estimates from 0.28 to 0.53, depending on the traits and season. A genetic map was built with 119 AFLP, SSR and SRAP markers positioned on 18 linkage groups (LG), for a total length of 884 cM, and used for quantitative trait loci (QTL) analysis. A major dominant gene, named ERs1, controlled the resistance to strains CMR134, PSS366, and GMI1000. Against strain PSS4, this gene was not detected, but a significant QTL involved in delay of disease progress was detected on another LG. The possible use of the major resistance gene ERs1 in marker-assisted selection and the prospects offered for academic studies of a possible gene for gene system controlling resistance to bacterial wilt in solanaceous plants are discussed.

Phylogeny and population structure of brown rot- and Moko disease-causing strains of Ralstonia solanacearum phylotype II.

The ancient soilborne plant vascular pathogen Ralstonia solanacearum has evolved and adapted to cause severe damage in an unusually wide range of plants. In order to better describe and understand these adaptations, strains with very similar lifestyles and host specializations are grouped into ecotypes. We used comparative genomic hybridization (CGH) to investigate three particular ecotypes in the American phylotype II group: (i) brown rot strains from phylotypes IIB-1 and IIB-2, historically known as race 3 biovar 2 and clonal; (ii) new pathogenic variants from phylotype IIB-4NPB that lack pathogenicity for banana but can infect many other plant species; and (iii) Moko disease-causing strains from phylotypes IIB-3, IIB-4, and IIA-6, historically known as race 2, that cause wilt on banana, plantain, and Heliconia spp. We compared the genomes of 72 R. solanacearum strains, mainly from the three major ecotypes of phylotype II, using a newly developed pangenomic microarray to decipher their population structure and gain clues about the epidemiology of these ecotypes. Strain phylogeny and population structure were reconstructed. The results revealed a phylogeographic structure within brown rot strains, allowing us to distinguish European outbreak strains of Andean and African origins. The pangenomic CGH data also demonstrated that Moko ecotype IIB-4 is phylogenetically distinct from the emerging IIB-4NPB strains. These findings improved our understanding of the epidemiology of important ecotypes in phylotype II and will be useful for evolutionary analyses and the development of new DNA-based diagnostic tools.

SU-E-T-252: Consolidating Duodenal/Small Bowel Toxicity Data via Iso-Effective Dose Calculations Based on Compiled Clinical Data.

PURPOSE: To consolidate duodenal toxicity data from clinical studies with different dose fractionation schemes using the modified linear quadratic (MLQ) model. A methodology of adjusting the dose-volume parameters todifferent levels of normal tissue complication probability (NTCP) was proposed and used to estimate dose-volume constrains for treatment planning. METHODS: A set of modified Lyman model parameters for duodenum NTCP were estimated by the chi-squared fitting method using tolerance dose and equivalent uniform dose (EUD) data obtained in a literature search. These model parameters were then used to convert the dose-volume pair, (D, V) to the iso-effective dose (in 2 Gy per fraction)- volume pair, (DMLQED2, V). A relationship was derived to convert a given DMLQED2 at one level of NTCP, to an iso-effective dose at another NTCP. RESULTS: The literature search yielded six reports useful in making estimates of small bowel/duodenal toxicity. The modified Lyman model parameters were found to be TD50 = 60.9 ± 7.9 Gy, m = 0.21 ± 0.05, and Î = 0.09 ± 0.03 Gy-1. The toxicity rates associated with hypo-fractionated radiotherapy (HBRT) were found to be consistent with other clinical data of conventional fractionations found in the literature. The conversion of DMLQED2 between different NTCP levels remains consistent with each other over a narrow range of NTCP. CONCLUSION: MLQ based iso-effective calculations of dose-response data corresponding to Grade > 2 toxicity were found to be consistent with one another within the uncertainty of DMLQED2 due to model parameter uncertainty. The dose-volume data that can be converted to different NTCP levels may be used to estimate duodenal/small bowel dose-volume constrains for new dose fractionation and/or dose escalation strategies. Medical College of Wisconsin Cancer Center Meinerz Foundation.

Bacterial wilt resistance in tomato, pepper, and eggplant: genetic resources respond to diverse strains in the Ralstonia solanacearum species complex.

Bacterial wilt, caused by strains belonging to the Ralstonia solanacearum species complex, inflicts severe economic losses in many crops worldwide. Host resistance remains the most effective control strategy against this disease. However, wilt resistance is often overcome due to the considerable variation among pathogen strains. To help breeders circumvent this problem, we assembled a worldwide collection of 30 accessions of tomato, eggplant and pepper (Core-TEP), most of which are commonly used as sources of resistance to R. solanacearum or for mapping quantitative trait loci. The Core-TEP lines were challenged with a core collection of 12 pathogen strains (Core-Rs2) representing the phylogenetic diversity of R. solanacearum. We observed six interaction phenotypes, from highly susceptible to highly resistant. Intermediate phenotypes resulted from the plants' ability to tolerate latent infections (i.e., bacterial colonization of vascular elements with limited or no wilting). The Core-Rs2 strains partitioned into three pathotypes on pepper accessions, five on tomato, and six on eggplant. A "pathoprofile" concept was developed to characterize the strain clusters, which displayed six virulence patterns on the whole set of Core-TEP host accessions. Neither pathotypes nor pathoprofiles were phylotype specific. Pathoprofiles with high aggressiveness were mainly found in strains from phylotypes I, IIB, and III. One pathoprofile included a strain that overcame almost all resistance sources.

Deciphering phenotypic diversity of Ralstonia solanacearum strains pathogenic to potato.

Based on the phylotype classification, we questioned how genetically and phenotypically diverse strains of Ralstonia solanacearum pathogenic to potato may be. We studied 129 European and Mediterranean strains along with 57 reference strains known to cover genetic diversity in this species. Phylogeny analysis was done on endoglucanase gene sequences. Pathogenicity to potato, tomato, and eggplant was established at 24 to 30°C and 15 to 24°C, whereas tests on banana were conducted at 24 to 30°C. The ability to cause wilt on species of Solanaceae was shared by strains in all four phylotypes. Brown rot phylotypes IIB-1 and IIB-2 and phylotype IIB-27 established latent infections in banana, and Moko disease-causing phylotypes IIA-6, IIB-3, and IIB-4 were virulent to susceptible potato and tomato, addressing the question of host adaptation mechanisms, which may have undergone a similar bottleneck evolution. Cold-tolerance ability is only shared on species of Solanaceae among brown rot phylotype IIB-1, which gathered the majority of European and Mediterranean strains. We surveyed strain LNPV24.25 as the first report of an emerging phylotype IIB-4NPB strain in France. These findings showed that pathogenicity traits of genetically identified strains still need to be understood, especially in the perspective of post-genomics comparative analysis, to understand bacterial speciation in the R. solanacearum species complex.

The c.859G>C variant in the SMN2 gene is associated with types II and III SMA and originates from a common ancestor.

Homozygous mutations of the telomeric SMN1 gene lead to degeneration of motor neurons causing spinal muscular atrophy (SMA). A highly similar centromeric gene (SMN2) can only partially compensate for SMN1 deficiency. The c.859G>C variant in SMN2 has been recently reported as a positive disease modifier. We identified the variant in 10 unrelated chronic SMA patients with a wide spectrum of phenotypes ranging from type II patients who can only sit to adult walkers. Haplotype analysis strongly suggests that the variant originated from a common ancestor. Our results confirm that the c.859G>C variant is a milder SMN2 allele and predict a direct correlation between SMN activity and phenotypic severity.

A New Type of Strain of Xanthomonas euvesicatoria Causing Bacterial Spot of Tomato and Pepper in Grenada.

Bacterial spot of tomato and pepper (BSTP) can be caused by several Xanthomonas genospecies (2). BSTP is a major disease in Grenada where A and B phenotypic groups (Xanthomonas euvesicatoria and X. vesicatoria, respectively, [2]) have been reported (3). There is no previous report of group A strains, which are strongly amylolytic and pectolytic, in Grenada. In March 2007, tomato and pepper leaves with lesions typical of BSTP were collected in Saint David and Saint Andrew parishes of Grenada. Bacterial isolations were performed on KC semiselective agar medium (4), resulting in isolation of five yellow-pigmented, Xanthomonas-like strains. Three strains isolated from tomato or pepper in Saint David were negative for starch hydrolysis and pectate degradation, two tests that were found useful for strain identification in the 1990s (2). Two strains isolated from pepper in Saint David were strongly amylolytic and degraded pectate. Amplified fragment length polymorphism (AFLP) and multilocus sequence analysis (MLSA) assays targeting atpD, dnaK, efp, and gyrB were performed on the five strains from Grenada together with a type strain of each of X. euvesicatoria, X. perforans, X. gardneri, and X. vesicatoria as well as other reference strains of X. euvesicatoria and X. perforans as described previously (1). All strains from Grenada were identified as X. euvesicatoria regardless of the typing technique. On the basis of AFLP assays, the two strains with phenotypic features not reported in Grenada were closely related (distances of ≤0.002 nucleotide substitutions per site [1]) to a group of strains from India (ICMP 3381, LMG 907, LMG 908, and LMG 918). These two strains were also identical to the Indian strains based on MLSA, but differed from the X. euvesicatoria type strain by at least one nucleotide substitution in all loci examined. The three strains from Grenada that were negative for starch hydrolysis and pectate degradation had sequences identical to that of the type strain. Young leaves of tomato plants of cv. Marmande and pepper plants of cvs. Yolo Wonder and Aiguille were infiltrated (six inoculation sites per leaf, three replicate plants per cultivar per experiment, and the experiment was replicated once) using inoculum of each of the five strains from Grenada made from suspensions in Tris buffer containing approximately 1 × 105 CFU/ml. Two reference strains of X. euvesicatoria (NCPPB 2968 and LMG 922) were also inoculated as positive control treatments. Negative control treatments consisted of leaves infiltrated with sterile Tris buffer. Typical water-soaked lesions that developed into necrotic spots were observed 3 to 8 days after inoculation (dai) for all strains on all cultivars, except NCPPB 2968, which was not pathogenic on pepper cv. Aiguille. Xanthomonas population sizes from lesions plated onto KC agar medium (4) 25 dai ranged from 3 × 106 to 5 × 107, 8 × 107 to 2 × 108, and 9 × 106 to 2 × 108 CFU/lesion on tomato cv. Marmande and pepper cvs. Yolo Wonder and Aiguille, respectively. The epidemiological importance of this previously unreported group of X. euvesicatoria strains in Grenada needs to be assessed. References: (1) L. Bui Thi Ngoc et al. Int. J. Syst. Evol. Microbiol. 60:515, 2010. (2) J. B. Jones et al. Syst. Appl. Microbiol. 27:755, 2004. (3) L. W. O'Garro. Plant Dis. 82:864, 1998. (4) O. Pruvost et al. J. Appl. Microbiol. 99:803, 2005.

Specific genes from the potato brown rot strains of Ralstonia solanacearum and their potential use for strain detection.

Ralstonia solanacearum is the agent of bacterial wilt infecting >200 different plant species covering >50 botanical families. The genus R. solanacearum can be classified into four phylotypes and each phylotype can be further subdivided into sequevars. The potato brown rot strains of R. solanacearum from phylotype IIB, sequevar 1 (IIB1), historically known as race 3, biovar 2 strains, are responsible for important economic losses to the potato industry and threaten ornamental crop production worldwide. Sensitive and specific detection methods are required to control this pathogen. This article provides a list of 70 genes and 15 intergenes specific to the potato brown rot strains of R. solanacearum from phylotype IIB1. This list was identified by comparative genomic hybridization on microarray and subsequent polymerase chain reaction validation with 14 IIB1 strains against 45 non-IIB1 strains that covered the known genetic diversity in R. solanacearum. The microarray used consisted of the previously described microarray representative of the phylotype I strain GMI1000, to which were added 660 70-mer oligonucleotides representative of new genomic islands detected in the phylotype IIB1 strain IPO1609. The brown rot strain-specific genes thus identified were organized in nine clusters covering 2 to 29 genes within the IPO1609 genome and 6 genes isolated along the genome. Of these specific genes, 29 were parts of mobile genetic elements. Considering the known instability of the R. solanacearum genome, we believe that multiple probes are required to consistently detect all IIB1 strains and we recommend the use of probes which are not part of genetic mobile elements.

Plant-pathogenic bacteria as biological weapons - real threats?

At present, much attention is being given to the potential of plant pathogens, including plant-pathogenic bacteria, as biological weapons/bioterror weapons. These two terms are sometimes used interchangeably and there is need for care in their application. It has been claimed that clandestine introduction of certain plant-pathogenic bacteria could cause such crop losses as to impact so significantly on a national economy and thus constitute a threat to national security. As a separate outcome, it is suggested that they could cause serious public alarm, perhaps constituting a source of terror. Legislation is now in place to regulate selected plant-pathogenic bacteria as potential weapons. However, we consider it highly doubtful that any plant-pathogenic bacterium has the requisite capabilities to justify such a classification. Even if they were so capable, the differentiation of pathogens into a special category with regulations that are even more restrictive than those currently applied in quarantine legislation of most jurisdictions offers no obvious benefit. Moreover, we believe that such regulations are disadvantageous insofar as they limit research on precisely those pathogens most in need of study. Whereas some human and animal pathogens may have potential as biological or bioterror weapons, we conclude that it is unlikely that any plant-pathogenic bacterium realistically falls into this category.

Severe haemophilia A in a female resulting from an inherited gross deletion and a de novo codon deletion in the F8 gene.

Haemophillia A (HA) is an X-linked bleeding disorder caused by mutations in the F8 gene. While the disease affects 1 in 5000 males, phenotypic expression of haemophilia A is rare in females, similar to other X-linked recessive disorders. We describe a 5-year-old female with severe haemophilia A. We determined the underlying molecular defect in the F8 genes of the proband and her closest family members by direct DNA sequencing, marker analysis and quantitative real-time polymerase chain reaction. The patient showed two different mutations in the F8 gene: the paternal copy of the F8 gene had a de novo p.Phe652/653 deletion in exon 13 while the maternally inherited gene showed a large deletion encompassing exons 1 to 22. The structural analysis of residues Phe652/Phe653 based on a three-dimensional model of activated factor VIII provides evidence of the impact of the mutant factor VIII protein in the clinical manifestations of the patient. This unusual finding highlights the need to perform a thorough molecular analysis including sequencing, marker and quantitative analyses to identify compound heterozygous females with HA.

Identification of QTLs for Ralstonia solanacearum race 3-phylotype II resistance in tomato.

Resistance against a Ralstonia solanacearum race 3-phylotype II strain JT516 was assessed in a F(2:3) and a population of inbred lines (RIL), both derived from a cross between L. esculentum cv. Hawaii 7996 (partially resistant) and L. pimpinellifolium WVa700 (susceptible). Resistance criteria used were the percentage of wilted plants to calculate the AUDPC value, and bacterial colonization scores in roots and stem (hypocotyl and epicotyl) assessed in two independent greenhouse experiments conducted during the cool and hot seasons in Réunion Island, France. Symptoms were more severe during the cool season trials. Heritability estimates in individual seasons ranged from 0.82 to 0.88, depending on resistance criterion. A set of 76 molecular markers was used for quantitative trait loci (QTL) mapping using the single- and composite- interval mapping methods, as well as ANOVA. Four QTLs, named Bwr- followed by a number indicating their map location, were identified. They explained from 3.2 to 29.8% of the phenotypic variation, depending on the resistance criterion and the season. A major QTL, Bwr-6, and a minor one, Bwr-3, were detected in each season for all resistance criteria. Both QTLs showed stronger effects in the hot season than in the cool one. Their role in resistance to R. solanacearum race 3-phylotype II was subsequently confirmed in the RIL population derived from the same cross. Two other QTLs, Bwr-4 and Bwr-8, with intermediate and minor effects, respectively, were only detected in the hot season, demonstrating that environmental factors may strongly influence the expression of resistance against the race 3-phylotype II strain JT516. These QTLs were compared with those detected in the RIL population against race 1-phylotype I strain JT519 as well as those detected in other previous studies in the same genetic background against other race 1-phylotype I and II strains. This comparison revealed the possible occurrence of some phylotype-specific resistance QTLs in Hawaii 7996.

The staphylocoagulase family of zymogen activator and adhesion proteins.

Staphylocoagulase (SC) secreted by Staphylococcus aureus is a potent non-proteolytic activator of the blood coagulation zymogen prothrombin and the prototype of a newly established zymogen activator and adhesion protein (ZAAP) family. The conformationally activated SC.prothrombin complex specifically cleaves fibrinogen to fibrin, which propagates the growth of bacteria-fibrin-platelet vegetations in acute bacterial endocarditis. Our recent 2.2 A X-ray crystal structures of an active SC fragment [SC(1-325)] bound to the prothrombin zymogen catalytic domain, prethrombin 2, demonstrated that SC(1-325) represents a new type of non-proteolytic activator with a unique fold. The observed insertion of the SC(1-325) N-terminus into the 'Ile 16' cleft of prethrombin 2, which triggers the activating conformational change, provided the first unambiguous structural evidence for the 'molecular sexuality' mechanism of non-proteolytic zymogen activation. Based on the SC(1-325) fold, a new family of bifunctional zymogen activator and adhesion proteins was identified that possess N-terminal domains homologous to SC(1-325) and C-terminal domains that mediate adhesion to plasma or extracellular matrix proteins. Further investigation of the ZAAP family may lead to new insights into the mechanisms of bacterial factors that hijack zymogens of the human blood coagulation and fibrinolytic systems to promote and disseminate endocarditis and other infectious diseases.

Structural basis for the activation of human procaspase-7.

Caspases form a family of proteinases required for the initiation and execution phases of apoptosis. Distinct proapoptotic stimuli lead to activation of the initiator caspases-8 and -9, which in turn activate the common executioner caspases-3 and -7 by proteolytic cleavage. Whereas crystal structures of several active caspases have been reported, no three-dimensional structure of an uncleaved caspase zymogen is available so far. We have determined the 2.9-A crystal structure of recombinant human C285A procaspase-7 and have elucidated the activation mechanism of caspases. The overall fold of the homodimeric procaspase-7 resembles that of the active tetrameric caspase-7. Each monomer is organized in two structured subdomains connected by partially flexible linkers, which asymmetrically occupy and block the central cavity, a typical feature of active caspases. This blockage is incompatible with a functional substrate binding site/active site. After proteolytic cleavage within the flexible linkers, the newly formed chain termini leave the cavity and fold outward to form stable structures. These conformational changes are associated with the formation of an intact active-site cleft. Therefore, this mechanism represents a formerly unknown type of proteinase zymogen activation.

The 2.0-A crystal structure of tachylectin 5A provides evidence for the common origin of the innate immunity and the blood coagulation systems.

Because invertebrates lack an adaptive immune system, they had to evolve effective intrinsic defense strategies against a variety of microbial pathogens. This ancient form of host defense, the innate immunity, is present in all multicellular organisms including humans. The innate immune system of the Japanese horseshoe crab Tachypleus tridentatus, serving as a model organism, includes a hemolymph coagulation system, which participates both in defense against microbes and in hemostasis. Early work on the evolution of vertebrate fibrinogen suggested a common origin of the arthropod hemolymph coagulation and the vertebrate blood coagulation systems. However, this conjecture could not be verified by comparing the structures of coagulogen, the clotting protein of the horseshoe crab, and of mammalian fibrinogen. Here we report the crystal structure of tachylectin 5A (TL5A), a nonself-recognizing lectin from the hemolymph plasma of T. tridentatus. TL5A shares not only a common fold but also related functional sites with the gamma fragment of mammalian fibrinogen. Our observations provide the first structural evidence of a common ancestor for the innate immunity and the blood coagulation systems.

Fine mapping of inhibitory anti-factor V antibodies using factor V C2 domain mutants. Identification of two antigenic epitopes involved in phospholipid binding.

Hemorrhagic factor V inhibitors frequently bind to the second C-type (C2) domain of factor V and interfere with phospholipid binding. To define specific residues recognized by inhibitors from four patients (one bovine thrombin-induced and three spontaneous antibodies), epitope mapping was performed using recombinant human factor V lacking most of the B-type domain (FV des B) and alanine-substituted mutants within the C2 domain (FV des B C2 mutants). FV des B C2 mutants located in the region between Lys2060 and Glu2069 were resistant to inhibition by three IgG preparations including the bovine thrombin-induced antibody in both prothrombinase and phospholipid-binding assays. In contrast, mutations at Lys2087 and Lys2092/Glu2096 were significantly resistant to inhibition by the fourth IgG preparation in both prothrombinase and phospholipid-binding assays. These results confirm interference of phospholipid binding by hemorrhagic factor V inhibitors and support the role(s) of these residues in phospholipid binding.

Natural history of cervical human papillomavirus infection in young women: a longitudinal cohort study.

BACKGROUND: Laboratory and epidemiological research suggests an association between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN). We studied the natural history of incident cervical HPV infection and its relation to the development of CIN. METHODS: We recruited 2011 women aged 15-19 years who had recently become sexually active. We took a cervical smear every 6 months and stored samples for virological analysis. We immediately referred all women with any cytological abnormality for colposcopic assessment, but postponed treatment until there was histological evidence of progression to high-grade CIN. FINDINGS: In 1075 women who were cytologically normal and HPV negative at recruitment, the cumulative risk at 3 years of any HPV infection was 44% (95% CI 40-48): HPV 16 was the most common type. The cumulative risk at 3 years of detecting an HPV type not present in the first positive sample was 26% (20-32). 246 women had an abnormal smear during follow-up, of whom 28 progressed to high-grade CIN. The risk of high-grade CIN was greatest in women who tested positive for HPV 16 (risk ratio 8.5 [3.7-19.2]); this risk was maximum 6-12 months after first detection of HPV 16. All HPV types under consideration were associated with cytologically abnormal smears. Although abnormality was significantly less likely to be associated with low-viral-load samples, the cumulative risk at 3 years of a high-viral-load sample after a low-viral-load sample was 45% (95% CI 35-56). Five women who progressed to high-grade CIN consistently tested negative for HPV. INTERPRETATION: Our findings suggest that attempts to exploit the association between cervical neoplasia and HPV infection to improve effectiveness of cervical screening programmes might be undermined by the limited inferences that can be drawn from the characterisation of a woman's HPV status at a single point in time, and the short lead time gained by its detection.

Gender trends in occupancy rates in mental health beds in Northern Ireland.

Based on census material from 1926 to 1991, this study focuses on gender differences in occupancy rates in mental health beds in Northern Ireland. More specifically, using two sets of research literature--the relationships between war and mental health and gender and mental health respectively--it explores changing patterns in bed occupancy in terms of both gender and age differences within this society. The results suggest that, although men and women no longer vary in terms of their overall occupancy rates within mental health facilities in Northern Ireland, within their respective male and female sub-populations, however, some notable age-specific differences have now emerged. Since 1981, whereas increases in mental health bed occupancy among women have been exclusively confined to the old (65 years or older), among males, it is the very young, specifically men aged 15-24 years, who have demonstrated the most dramatic rise in bed usage. It is important to note, however, that these age-specific gender increases cannot be accounted for by demographic changes in the general population. The authors suggest that, at least as far as men are concerned, the increasing pattern of vulnerability among the young may be attributed to the impact of changing definitions of mental disorder rather than to the effect of political violence on mental health. It is to this group of individuals--the cohort of men born since the outbreak of civil unrest in Northern Ireland in 1969--that future research should be directed.

Marital status and bed occupancy in health and social care facilities in the United Kingdom.

The purpose of the study was to test the hypothesis that marriage and physical health are positively related.A secondary analysis was performed of census data on all individuals aged 15 y and over occupying beds in general health and social care facilities (excluding mental health) in England and Wales, Scotland, and Northern Ireland in 1971, 1981 and 1991. Using bed occupancy in health and social care facilities as a proxy for ill health, this paper investigates the relationship between marital status and physical health in the United Kingdom. The findings, expressed as the proportion of individuals (excluding staff and visitors) aged 15 y and over within these facilities, suggest that: a) Whether considered separately or together, married men and women are healthier than non-married men and women, as reflected in their much lower use of health and social care beds; b) This positive relationship between marriage and health has increased steadily since the 1970s; c) Within the non-married population, whereas the single are most at risk among men, the widowed are most at risk among women; d) In contrast to the married and widowed, there are some consistent age-specific gender differences among the divorced and single, with men of working age at much higher risk than women of working age. This study confirms research findings elsewhere that marriage and physical health are positively related. Throughout the United Kingdom, not only are married people healthier than non-married people, as reflected in their much lower use of health and social care beds, but this relationship holds irrespective of gender.

Crystal structure of the human alpha-thrombin-haemadin complex: an exosite II-binding inhibitor.

The serine proteinase alpha-thrombin plays a pivotal role in the regulation of blood fluidity, and therefore constitutes a primary target in the treatment of various haemostatic disorders. Haemadin is a slow tight- binding thrombin inhibitor from the land-living leech Haemadipsa sylvestris. Here we present the 3.1 A crystal structure of the human alpha-thrombin- haemadin complex. The N-terminal segment of haemadin binds to the active site of thrombin, forming a parallel beta-strand with residues Ser214-Gly216 of the proteinase. This mode of binding is similar to that observed in another leech-derived inhibitor, hirudin. In contrast to hirudin, however, the markedly acidic C-terminal peptide of haemadin does not bind the fibrinogen-recognition exosite, but interacts with the heparin-binding exosite of thrombin. Thus, haemadin binds to thrombin according to a novel mechanism, despite an overall structural similarity with hirudin. Haemadin inhibits both free and thrombomodulin-bound alpha-thrombin, but not intermediate activation forms such as meizothrombin. This specific anticoagulant ability of haemadin makes it an ideal candidate for an antithrombotic agent, as well as a starting point for the design of novel antithrombotics.