Phylogeographic pattern of range expansion provides evidence for cryptic species lineages in Silene nutans in Western Europe.

As a result of recent or past evolutionary processes, a single species might consist of distinct Evolutionary Significant Units (ESUs), even corresponding to cryptic species. Determining the underlying mechanisms of range shifts and the processes at work in the build-up of divergent ESUs requires elucidating the factors that contribute to population genetic divergence across a species' range. We investigated the large-scale patterns of genetic structure in the perennial herbaceous plant species Silene nutans (Caryophyllaceae) in Western Europe. We sampled and genotyped 111 populations using 13 nuclear microsatellite loci and 6 plastid single-nucleotide polymorphisms. Broad-scale spatial population genetic structure was examined using Bayesian clustering, spatial multivariate analyses and measures of hierarchical genetic differentiation. The genotypic structure of S. nutans was typical of a predominantly allogamous mating system. We also identified plastid lineages with no intra-population polymorphism, mirroring two genetically differentiated nuclear lineages. No evidence of admixture was found. Spatial trends in genetic diversity further suggested independent leading-edge expansion associated with founding events and subsequent genetic erosion. Overall, our findings suggested speciation processes in S. nutans and highlighted striking patterns of distinct stepwise recolonisation of Western Europe shaped by Quaternary climate oscillations. Two main potential ESUs can be defined in Western Europe, corresponding to Eastern and Western nuclear-plastid lineages. In situ preservation of populations and genetic rescue implying ex situ conservation techniques should take the lineage identity into account. This is particularly true in Great Britain, northern France and Belgium, where S. nutans is rare and where distinct lineages co-occur in close contact.

Disentangling the effects of mating systems and mutation rates on cytoplasmic [correction of cytoplamic] diversity in gynodioecious Silene nutans and dioecious Silene otites.

Many flowering plant species exhibit a variety of distinct sexual morphs, the two most common cases being the co-occurrence of females and males (dioecy) or the co-occurrence of hermaphrodites and females (gynodioecy). In this study, we compared DNA sequence variability of the three genomes (nuclear, mitochondrial and chloroplastic) of a gynodioecious species, Silene nutans, with that of a closely related dioecious species, Silene otites. In the light of theoretical models, we expect cytoplasmic diversity to differ between the two species due to the selective dynamics that acts on cytoplasmic genomes in gynodioecious species: under an epidemic scenario, the gynodioecious species is expected to exhibit lower cytoplasmic diversity than the dioecious species, while the opposite is expected in the case of balancing selection maintaining sterility cytoplasms in the gynodioecious species. We found no difference between the species for nuclear gene diversity, but, for the cytoplasmic loci, the gynodioecious S. nutans had more haplotypes, and higher nucleotide diversity, than the dioecious relative, S. otites, even though the latter has a relatively high rate of mitochondrial synonymous substitutions, and therefore presumably a higher mutation rate. Therefore, as the mitochondrial mutation rate cannot account for the higher cytoplasmic diversity found in S. nutans, our findings support the hypothesis that gynodioecy in S. nutans has been maintained by balancing selection rather than by epidemic-like dynamics.

Structural and content diversity of mitochondrial genome in beet: a comparative genomic analysis.

Despite their monophyletic origin, mitochondrial (mt) genomes of plants and animals have developed contrasted evolutionary paths over time. Animal mt genomes are generally small, compact, and exhibit high mutation rates, whereas plant mt genomes exhibit low mutation rates, little compactness, larger sizes, and highly rearranged structures. We present the (nearly) whole sequences of five new mt genomes in the Beta genus: four from Beta vulgaris and one from B. macrocarpa, a sister species belonging to the same Beta section. We pooled our results with two previously sequenced genomes of B. vulgaris and studied genome diversity at the species level with an emphasis on cytoplasmic male-sterilizing (CMS) genomes. We showed that, contrary to what was previously assumed, all three CMS genomes belong to a single sterile lineage. In addition, the CMSs seem to have undergone an acceleration of the rates of substitution and rearrangement. This study suggests that male sterility emergence might have been favored by faster rates of evolution, unless CMS itself caused faster evolution.

Genetic determination of male sterility in gynodioecious Silene nutans.

Gynodioecy, the coexistence of female and hermaphrodite plants within a species, is often under nuclear-cytoplasmic sex determination, involving cytoplasmic male sterility (CMS) genes and nuclear restorers. A good knowledge of CMS and restorer polymorphism is essential for understanding the evolution and maintenance of gynodioecy, but reciprocal crossing studies remain scarce. Although mitochondrial diversity has been studied in a few gynodioecious species, the relationship between mitotype diversity and CMS status is poorly known. From a French sample of Silene nutans, a gynodioecious species whose sex determination remains unknown, we chose the four most divergent mitotypes that we had sampled at the cytochrome b gene and tested by reciprocal crosses whether they carry distinct CMS genes. We show that gynodioecy in S. nutans is under nuclear-cytoplasmic control, with at least two different CMSs and up to four restorers with epistatic interactions. Female occurrence and frequency were highly dependent on the mitotype, suggesting that the level of restoration varies greatly among CMSs. Two of the mitotypes, which have broad geographic distributions, represent different CMSs and are very unequally restored. We discuss the dynamics of gynodioecy at the large-scale meta-population level.

Variation in pollen production and pollen viability in natural populations of gynodioecious Beta vulgaris ssp. maritima: evidence for a cost of restoration of male function?

Gynodioecious species are defined by the co-occurrence of two clearly separated categories of plants: females and hermaphrodites. The hermaphroditic category may, however, not be homogeneous, as male fitness may vary among hermaphrodites as a result of many biological factors. In this study, we analysed estimates of pollen quantity and viability in the gynodioecious Beta vulgaris ssp. maritima, comparing hermaphrodites bearing a male-fertile cytotype and hermaphrodites bearing cytoplasmic male sterility (CMS) genes, which are counteracted by nuclear restoration factors. We show that: (i) pollen quantity continuously varies among restored hermaphrodites, suggesting a complex genetic determination of nuclear restoration; (ii) pollen viability was lower in restored (CMS) hermaphrodites than in non-CMS hermaphrodites, probably because of incomplete restoration in some of these plants; and (iii) pollen quantity and viability also varied among hermaphrodites with male-fertile cytotypes, possibly a result of a silent cost of restoration. Finally, we discuss the consequences of these results for pollen flow and the dynamics of gynodioecy.

Comparative effectiveness of sugar beet microsatellite markers isolated from genomic libraries and GenBank ESTs to map the sugar beet genome.

Sugar beet (Beta vulgaris) is an important root crop for sucrose production. A study was conducted to find a new abundant source of microsatellite (SSR) markers in order to develop marker assistance for breeding. Different sources of existing microsatellites were used and new ones were developed to compare their efficiency to reveal diversity in mapping population and mapping coverage. Forty-one microsatellite markers were isolated from a B. vulgaris ssp maritima genomic library and 201 SSRs were extracted from a B. vulgaris ssp vulgaris library. Data mining was applied on GenBank B. vulgaris expressed sequence tags (ESTs), 803 EST-SSRs were identified over 19,709 ESTs. Characteristics, polymorphism and cross-species transferability of these microsatellites were compared. Based on these markers, a high density genetic map was constructed using 92 F(2) individuals from a cross between a sugar and a table beet. The map contains 284 markers, spans over 555 cM and covers the nine chromosomes of the species with an average markers density of one marker every 2.2 cM. A set of markers for assignation to the nine chromosomes of sugar beet is provided.

Modelling the maintenance of male-fertile cytoplasm in a gynodioecious population.

Gynodioecy is the co-occurrence of females and hermaphrodites in populations. It is usually due to the combined action of cytoplasmic male sterility (CMS) genes and nuclear genes that restore male fertility. According to previous theoretical studies, it is very difficult to explain the maintenance of gynodioecy with CMS and male-fertile cytotypes, although it has been observed in some species. However, only very specific situations have been investigated so far. We present a model to investigate the conditions that promote the maintenance of this breeding system in the case of an outcrossed species when CMS and male-fertile (non-CMS) cytotypes are present in an infinite panmictic population. We show that the type of cost of restoration strongly affects the conditions for stable maintenance of gynodioecy. Stable nuclear-cytoplasmic gynodioecy requires a female advantage, which is a classical condition for gynodioecy, but also a cost of CMS for female fitness, which had been rarely investigated. A cost of restoration is also needed, which could affect either pollen or seeds. Finally, we found that gynodioecy was attainable for a large set of parameter values, including low differences in fitness among genotypes and phenotypes. Our theoretical predictions are compared with previous theoretical work and with results of empirical studies on various gynodioecious species.

The male sterile G cytoplasm of wild beet displays modified mitochondrial respiratory complexes.

Cytoplasmic male sterility (CMS) in higher plants has been mainly studied in cultivated species. In most cases, pollen abortion is linked to the presence of an additional mitochondrial polypeptide leading to organelle dysfunction in reproductive tissues. In wild beet, both CMS and hermaphrodite plants coexist in natural populations. The G cytoplasm is widely distributed along the Western European coast, and previous genetic studies have demonstrated that this cytoplasm confers male sterility in beet. In the present study, we have identified two mutations of G mitochondrial genes, each of which results in the production of a respiratory chain complex subunit with an altered molecular weight; the NAD9 subunit has a C-terminal extension while the COX2 subunit has a truncated C-terminus. NADH dehydrogenase activity was unchanged in leaves, but cytochrome c oxidase activity was reduced by 50%. Moreover, Western blot analyses revealed that alternative oxidase was more abundant in male sterile G plants than in a fertile control (Nv), suggesting that this alternative pathway might compensate for the cytochrome c oxidase deficiency. Implications of respiratory chain changes and a putative link with CMS are discussed.

[Pott's disease paraplegia in children. Mechanics and therapeutic strategies. Six cases]. / Paraplégie d'origine pottique chez l'enfant. Mécanismes et stratégies thérapeutiques. A propos de 6 cas.

PURPOSE: We report a series of 6 Pott's disease paraplegias treated between 1982 and 1996. MATERIALS AND METHOD: Out of 15 children suffering from Pott's disease, 6 had paraplegia. Treatment consisted of anterior medullar decompression and anterior spine fusion with bone grafting. Two or three weeks later, posterior spine fusion was achieved systematically using a CD fixation device in 3 cases. RESULTS: Neurological signs completely disappeared in 5 children. Vertebral fusion was correct in all patients and kyphosis was less than 50 degrees. DISCUSSION: The posterior approach to the spine must be proscribed as a first step, except for spine dislocation. The anterior approach allowed us to drain the abscess, to correct the kyphosis, and to perform an anterior spine fusion. The posterior spine fusion was performed a few weeks later in order to avoid kyphosis aggravation. CONCLUSION: Prognosis of Pott's disease is good but at the present time, paraplegia remains too frequent. Adapted treatment must be performed without delay.

[Pyogenic sacroiliitis in children. Apropos of 11 cases]. / Sacro-iliites à pyogène de l'enfant. A propos de 11 cas.

PURPOSE OF THE STUDY: Sacroiliitis in children is a rare disease. Since 1878, only 100 cases have been reported in the international literature. MATERIALS AND METHODS: We reviewed a series of 11 cases (mean age of 7.75 years) with a delay of 45 months. All the patients had limp, and hip pain. RESULTS: The clinical examination found each time F.A.B.E.R.E. and Glaensen signs. The hip mobility was limited most of time. There was a non specific inflammatory syndrome. Roentgenogram signs were delayed, and associated widening of the joint, geodes, condensation, and at an ultimate stage, fusion of the joint. Tc 99m scintigraphy always showed the localisation. DISCUSSION: This examination shortened the diagnosis delay, C-T scan was performed twice. It allowed visualize the local extension and complication such as abscess. It facilitated the indication of the surgical approach, and results can be appreciated through follow up CT scan studies. The germ was rarely determined as it has been reported in the literature. Therefore an articular ponction must be performed each time a sacroiliitis is suspected, under general anesthesia and associated to an arthrography or under CT scan control. Surgical drains were placed five times only. The authors limited their indication to an important collection, an abscess, or an intra-articular sequestra. CONCLUSION: At the maximum follow up (mean 45 months) all patients had a normal clinical exam. Each time there were joint modification on the roentgenogramm but without any functional correlation.

[A method of cost evaluation of orthopedic treatment of femoral diaphyseal fractures in school-age children]. / Une méthode d'évaluation du coût du traitement orthopédique des fractures diaphysaires du fémur chez l'enfant d'âge scolaire.

PURPOSE OF THE STUDY: Femoral diaphysis fractures are very frequent in children. The objective of this study was to evaluate the cost of orthopaedic treatment for femoral diaphysis fracture in school's age children. MATERIAL AND METHODS: 50 femoral fractures were reviewed at an average of 5 years follow-up with many economic parameters. DISCUSSION: Different treatments are available for this type of fracture. Actually, there is a controversy between orthopaedic and surgical treatment and no one gives better long term results. Therefore economic reasons can help for the choice of the method when the final result is equivalent. The same study should be realized for other available fracture treatments. CONCLUSION: Future studies should use the same methodology in order to obtain the real cost of each treatment.

Amino acid analysis of proteins separated by two-dimensional electrophoresis in maize: isoform detection and function identification.

The possibility of using experimentally determined amino acid composition to assess relatedness between 75 proteins separated by two-dimensional electrophoresis (2-DE) and to identify them was tested on maize. Two independent parameters, the relative Euclidean distance and the correlation coefficient between the amino acid compositions, were evaluated and used. Previous sequence information for 31 out of the 75 proteins made it possible to evaluate the method for the detection of isoforms and for identification. However, the extension of the interrogation beyond maize to all plant sequences raised the problem of false positives that could nevertheless be limited by replications and by using additional information. The efficiency of the method to assess relatedness between proteins should make amino acid composition analysis a valuable tool in large protein characterization programs based on 2-DE, by facilitating the transfer of information from one well-documented organ/tissue or genotype to another.

[Total hip prosthesis for chronic juvenile arthritis. A review of a series of 34 prosthesis]. / Arthroplastie totale de hanche dans l'arthrite chronique juvénile. Revue d'une série de 34 prothèses.

PURPOSE OF THE STUDY: The purpose of this study was to analyse the results of total hip arthroplasty for chronic juvenile arthritis in order to evaluate risks, problems and benefits of this procedure. MATERIAL AND METHODS: Between 1984 and 1992, 34 total hip prostheses were implanted for chronic juvenile arthritis in 20 patients. Most prosthesis were Zweymuller cementless prosthesis. Mean follow up was 5 years. RESULTS: Results were good. In 85 per cent of cases, patients had a normal activity recovery. Pain relief was very good since in 80 per cent cases patients had a total indolence. DISCUSSION: Beyond these good clinical results at this mean follow-up, the main interest of this study is to characterize two different periods in the surgical technique. The first period when cemented prosthesis was employed and the second one when cementless femoral implants with screwed acetabular component were used. Cementless prostheses appear to be a satisfying solution in this disease, preserving bones and showing very good radiological and functional results. CONCLUSION: Furthermore, the very low complication rate despite general discomfort may prompt us to use total hip arthroplasty for the treatment of chronic juvenile arthritis.

[Brucellosis of the pubic symphysis. Apropos of a case. Review of the literature]. / Infection mélitoccocique de la symphyse pubienne. A propos d'un cas, revue de la littérature.

The authors report a case of symphysis pubis osteomyelitis due to Brucella. Such localisation seems not to have been reported before. Despite an initially bad observance of antibiotic treatment, evolution has finally been favourable. At two year follow-up, no functional or radiological sequellae was observed.

The maize two-dimensional gel protein database: towards an integrated genome analysis program.

This paper describes the first maize database of proteins separated by two-dimensional electrophoresis. Fifty-six coleoptile proteins and 18 leaf proteins from two maize lines were partially microsequenced. Thirty-six proteins (49%) displayed high similarity with database proteins. Nine of these proteins, representing five different functions, had never been described in maize. No conclusive function could be found for 45 polypeptides (61% of the microsequenced proteins). In addition, an alternative identification method, based on amino acid analysis, allowed candidates to be proposed for 17 proteins out of 44 additional proteins analyzed in the coleoptiles. These results are stored in a database which also includes, when available, genetic information about the chromosomal location of structural genes and regulatory factors of proteins. This database is being used in the context of a project on the genetic mapping of the expressed genome in maize.

Chronic septic arthritis and osteomyelitis in a prosthetic knee joint due to Clostridium difficile.

A case of chronic septic arthritis and osteomyelitis in a prosthetic knee joint due to Clostridium difficile is reported. A knee prosthesis was installed in a 16-year-old boy for surgical treatment of an osteosarcoma of the femur. Later, the patient suffered a traumatic closed fracture of his patella, and a sterile fluid was aspirated. One month later, the joint displayed inflammation. Culture of the articular fluid yielded a nontoxigenic Clostridium difficile strain. Despite several attempts using conservative medical treatment with penicillins and ornidazole, Clostridium difficile strains with the same antibiotic susceptibility pattern were repeatedly isolated from the joint over an eight-month period. The foreign material was then ablated, and finally, the patient's leg was amputated one year after Clostridium difficile was first isolated. The possible sources of contamination in our case and other reported cases of extraintestinal infection due to Clostridium difficile are discussed.

Characterizing allelic proteins for genome mapping in maize.

Mapping cDNA probes in order to construct genetic linkage maps is becoming a widespread strategy for genome analysis and gene isolation, particularly in cultivated plant species. Nevertheless, almost all cDNAs reveal two or more unlinked loci, making it difficult to identify the gene(s) actually expressed. In a highly polymorphic species, such as maize, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) of proteins may circumvent this limitation. With the analysis of various segregating populations, we previously showed that the apparent position shifts of proteins on the 2-D gels are monogenic and codominant. In this paper we compared allelic proteins on the basis of their high performance liquid chromatography (HPLC) profile and partial amino acid sequences. In a sample of 20 position shifts, the allelic proteins appeared to be similar in all but one case, strongly suggesting that polymorphism of structural genes is involved. Thus 2-D PAGE could prove to be a useful tool for genome mapping: when a cDNA probe detects several loci, a position shift of the encoded protein will allow the identification of the gene translated in the organ considered.

[Essential bone cysts in children. Value of systematic cystography. Apropos of a series of 42 cysts]. / Kystes osseux essentiels de l'enfant: intérêt de la kystographie systématique. A propos d'une série de 42 kystes.

INTRODUCTION: The treatment of children's essential bone cysts, is controversial. Intra focal injection of a corticoid, the Methylprednisolone, described by Scaglietti in 1974, given in most of the case serials, a rate of healing of more than 30 per cent. MATERIAL AND METHODS: The case serial we present include 42 essential bone cysts treated between 1975 and 1992 in the orthopaedic department of Necker Enfants Malades hospital. These children have been reviewed with a mean follow up of 4 years. A healing rate over 35 per cent has been noticed. However, some failures stayed completely an understanding even if nothing at the beginning let suppose a slower evolution. RESULTS: Attempting to explain those phenomenes, the authors realised in 70 per cent cases, an opaque cystography, before the Methylprednisolone injection. This simple radiological technique permitted to reveal abnormal aspect in 75 per cent cases. Most of the time, it shows massive-veinous licks in an abnormal veinous system or one or plurial separations of the cystic area. This type of picture could perfectly explain the defect of the corticoids action by a lick of the solution or by a partial unefficacity of the solution because of the separation in the cyst area. The hypothetic idea has been completed by the calcul of the duration of the evolution. Effectively, the cysts showing an abnormal cystography had a longer healing delay compared to the cyst whose cystography was normal. CONCLUSION: The opaque cystography is for us a necessary element in the treatment of essential bones cysts, once the diagnostic is certain and the indication of intra focal corticoid injection has been retained. The radiographic study of the cyst area permits to precise the treatment; for example multiplying the injections in the areas of the cysts when there is separations and overseing the evolution.

[Value of pelvic osteotomy in the management of the hip in children with cerebral palsy]. / Intérêt de l'ostéotomie pelvienne dans la prise en charge de la hanche de l'enfant IMC.

PURPOSE OF THE STUDY: The authors analyzed the effectiveness of pelvic osteotomy for the treatment of hip dislocation or subluxation in CP children. MATERIAL: Fifteen pelvic osteotomies were performed on 11 children aged 30 months to 12 years (mean age 6 years). Seven children suffered from Little's disease. Follow-up averaged 10 years (from 2 to 16). Six children were reviewed at the end of growth (9 cases). METHODS: A Salter or triple osteotomy with adductor release was performed. Four cases had also a proximal femoral osteotomy. RESULTS: Following surgery, the mean Reimers' percentage decreased from 55 to 0 per cent. Correction was perfect in 11 cases, incomplete in 4 but excentration remained under 20 per cent. At the end of growth, 6 out of 9 hips remained stable without any further surgery, 2 hips developed slight excentration (less than 20 per cent) and one recurrent subluxation was treated by proximal femoral osteotomy. Six hips remained stable but their growth was not ended at last review. DISCUSSION: This surgical procedure is compared to others described in literature. Pelvic osteotomy with tenotomy improves acetabular cover and corrects muscle imbalance. Its risks seem overestimated in the literature. Both pelvic and femoral osteotomies are useful in specific cases. CONCLUSION: Triple or Salter osteotomy with adducter release seems to be a useful procedure to restore good hip morphology at the end of growth. No posterior dislocations following this osteotomy were seen in spite of the important correction. Proximal femoral osteotomy is not always necessary.