Age of the oldest known Homo sapiens from eastern Africa.

Efforts to date the oldest modern human fossils in eastern Africa, from Omo-Kibish1-3 and Herto4,5 in Ethiopia, have drawn on a variety of chronometric evidence, including 40Ar/39Ar ages of stratigraphically associated tuffs. The ages that are generally reported for these fossils are around 197 thousand years (kyr) for the Kibish Omo I3,6,7, and around 160-155 kyr for the Herto hominins5,8. However, the stratigraphic relationships and tephra correlations that underpin these estimates have been challenged6,8. Here we report geochemical analyses that link the Kamoya's Hominid Site (KHS) Tuff9, which conclusively overlies the member of the Omo-Kibish Formation that contains Omo I, with a major explosive eruption of Shala volcano in the Main Ethiopian Rift. By dating the proximal deposits of this eruption, we obtain a new minimum age for the Omo fossils of 233 ± 22 kyr. Contrary to previous arguments6,8, we also show that the KHS Tuff does not correlate with another widespread tephra layer, the Waidedo Vitric Tuff, and therefore cannot anchor a minimum age for the Herto fossils. Shifting the age of the oldest known Homo sapiens fossils in eastern Africa to before around 200 thousand years ago is consistent with independent evidence for greater antiquity of the modern human lineage10.

Reconciling the climate and ozone response to the 1257 CE Mount Samalas eruption.

The 1257 CE eruption of Mount Samalas (Indonesia) is the source of the largest stratospheric injection of volcanic gases in the Common Era. Sulfur dioxide emissions produced sulfate aerosols that cooled Earth's climate with a range of impacts on society. The coemission of halogenated species has also been speculated to have led to wide-scale ozone depletion. Here we present simulations from HadGEM3-ES, a fully coupled Earth system model, with interactive atmospheric chemistry and a microphysical treatment of sulfate aerosol, used to assess the chemical and climate impacts from the injection of sulfur and halogen species into the stratosphere as a result of the Mt. Samalas eruption. While our model simulations support a surface air temperature response to the eruption of the order of -1°C, performing well against multiple reconstructions of surface temperature from tree-ring records, we find little evidence to support significant injections of halogens into the stratosphere. Including modest fractions of the halogen emissions reported from Mt. Samalas leads to significant impacts on the composition of the atmosphere and on surface temperature. As little as 20% of the halogen inventory from Mt. Samalas reaching the stratosphere would result in catastrophic ozone depletion, extending the surface cooling caused by the eruption. However, based on available proxy records of surface temperature changes, our model results support only very minor fractions (1%) of the halogen inventory reaching the stratosphere and suggest that further constraints are needed to fully resolve the issue.

De novo mutation screening in childhood-onset cerebellar atrophy identifies gain-of-function mutations in the CACNA1G calcium channel gene.

Cerebellar atrophy is a key neuroradiological finding usually associated with cerebellar ataxia and cognitive development defect in children. Unlike the adult forms, early onset cerebellar atrophies are classically described as mostly autosomal recessive conditions and the exact contribution of de novo mutations to this phenotype has not been assessed. In contrast, recent studies pinpoint the high prevalence of pathogenic de novo mutations in other developmental disorders such as intellectual disability, autism spectrum disorders and epilepsy. Here, we investigated a cohort of 47 patients with early onset cerebellar atrophy and/or hypoplasia using a custom gene panel as well as whole exome sequencing. De novo mutations were identified in 35% of patients while 27% had mutations inherited in an autosomal recessive manner. Understanding if these de novo events act through a loss or a gain of function effect is critical for treatment considerations. To gain a better insight into the disease mechanisms causing these cerebellar defects, we focused on CACNA1G, a gene not yet associated with the early-onset form. This gene encodes the Cav3.1 subunit of T-type calcium channels highly expressed in Purkinje neurons and deep cerebellar nuclei. We identified four patients with de novo CACNA1G mutations. They all display severe motor and cognitive impairment, cerebellar atrophy as well as variable features such as facial dysmorphisms, digital anomalies, microcephaly and epilepsy. Three subjects share a recurrent c.2881G>A/p.Ala961Thr variant while the fourth patient has the c.4591A>G/p.Met1531Val variant. Both mutations drastically impaired channel inactivation properties with significantly slower kinetics (∼5 times) and negatively shifted potential for half-inactivation (>10 mV). In addition, these two mutations increase neuronal firing in a cerebellar nuclear neuron model and promote a larger window current fully inhibited by TTA-P2, a selective T-type channel blocker. This study highlights the prevalence of de novo mutations in early-onset cerebellar atrophy and demonstrates that A961T and M1531V are gain of function mutations. Moreover, it reveals that aberrant activity of Cav3.1 channels can markedly alter brain development and suggests that this condition could be amenable to treatment.

Ancient Heavy Metal Contamination in Soils as a Driver of Tolerant Anthyllis vulneraria Rhizobial Communities.

Anthyllis vulneraria is a legume associated with nitrogen-fixing rhizobia that together offer an adapted biological material for mine-soil phytostabilization by limiting metal pollution. To find rhizobia associated with Anthyllis at a given site, we evaluated the genetic and phenotypic properties of a collection of 137 rhizobia recovered from soils presenting contrasting metal levels. Zn-Pb mine soils largely contained metal-tolerant rhizobia belonging to Mesorhizobium metallidurans or to another sister metal-tolerant species. All of the metal-tolerant isolates harbored the cadA marker gene (encoding a metal-efflux PIB-type ATPase transporter). In contrast, metal-sensitive strains were taxonomically distinct from metal-tolerant populations and consisted of new Mesorhizobium genospecies. Based on the symbiotic nodA marker, the populations comprise two symbiovar assemblages (potentially related to Anthyllis or Lotus host preferences) according to soil geographic locations but independently of metal content. Multivariate analysis showed that soil Pb and Cd concentrations differentially impacted the rhizobial communities and that a rhizobial community found in one geographically distant site was highly divergent from the others. In conclusion, heavy metal levels in soils drive the taxonomic composition of Anthyllis-associated rhizobial populations according to their metal-tolerance phenotype but not their symbiotic nodA diversity. In addition to heavy metals, local soil physicochemical and topoclimatic conditions also impact the rhizobial beta diversity. Mesorhizobium communities were locally adapted and site specific, and their use is recommended for the success of phytostabilization strategies based on Mesorhizobium-legume vegetation. IMPORTANCE: Phytostabilization of toxic mine spoils limits heavy metal dispersion and environmental pollution by establishing a sustainable plant cover. This eco-friendly method is facilitated by the use of selected and adapted cover crop legumes living in symbiosis with rhizobia that can stimulate plant growth naturally through biological nitrogen fixation. We studied microsymbiont partners of a metal-tolerant legume, Anthyllis vulneraria, which is tolerant to very highly metal-polluted soils in mining and nonmining sites. Site-specific rhizobial communities were linked to taxonomic composition and metal tolerance capacity. The rhizobial species Mesorhizobium metallidurans was dominant in all Zn-Pb mines but one. It was not detected in unpolluted sites where other distinct Mesorhizobium species occur. Given the different soil conditions at the respective mining sites, including their heavy-metal contamination, revegetation strategies based on rhizobia adapting to local conditions are more likely to succeed over the long term compared to strategies based on introducing less-well-adapted strains.

Identification and typing of the emerging pathogen Candida auris by matrix-assisted laser desorption ionisation time of flight mass spectrometry.

Candida auris is an emerging antifungal resistant yeast species causing nosocomial and invasive infections, emphasising the need of improved diagnostics and epidemiological typing methods. We show that MALDI-TOF VITEK-MS followed by amplified length polymorphisms allows for accurate species identification and subsequent epidemiological characterisation of strains encountered during potential outbreaks.

Source of the great A.D. 1257 mystery eruption unveiled, Samalas volcano, Rinjani Volcanic Complex, Indonesia.

Polar ice core records attest to a colossal volcanic eruption that took place ca. A.D. 1257 or 1258, most probably in the tropics. Estimates based on sulfate deposition in these records suggest that it yielded the largest volcanic sulfur release to the stratosphere of the past 7,000 y. Tree rings, medieval chronicles, and computational models corroborate the expected worldwide atmospheric and climatic effects of this eruption. However, until now there has been no convincing candidate for the mid-13th century "mystery eruption." Drawing upon compelling evidence from stratigraphic and geomorphic data, physical volcanology, radiocarbon dating, tephra geochemistry, and chronicles, we argue the source of this long-sought eruption is the Samalas volcano, adjacent to Mount Rinjani on Lombok Island, Indonesia. At least 40 km(3) (dense-rock equivalent) of tephra were deposited and the eruption column reached an altitude of up to 43 km. Three principal pumice fallout deposits mantle the region and thick pyroclastic flow deposits are found at the coast, 25 km from source. With an estimated magnitude of 7, this event ranks among the largest Holocene explosive eruptions. Radiocarbon dates on charcoal are consistent with a mid-13th century eruption. In addition, glass geochemistry of the associated pumice deposits matches that of shards found in both Arctic and Antarctic ice cores, providing compelling evidence to link the prominent A.D. 1258/1259 ice core sulfate spike to Samalas. We further constrain the timing of the mystery eruption based on tephra dispersal and historical records, suggesting it occurred between May and October A.D. 1257.

Development and real-life use assessment of a self-management smartphone application for patients with inflammatory arthritis. A user-centred step-by-step approach.

BACKGROUND: Mobile health applications (apps) are increasing in interest to enhance patient self-management. Few apps are actually used by patients and have been developed for patients with inflammatory arthritis (IA) treated with disease-modifying anti-rheumatic drugs which use entails risk of adverse effects such as infections. OBJECTIVE: To develop Hiboot, a self-management mobile app for patients with IA, by using a user-centred step-by-step approach and assess its real-life use. METHODS: The app development included first a qualitative study with semi-guided audiotaped interviews of 21 patients to identify the impact of IA on daily life and patient treatments practices and an online cross-sectional survey of 344 patients to assess their health apps use in general and potential user needs. A multidisciplinary team developed the first version of the app via five face-to-face meetings. After app launch, a second qualitative study of 21 patients and a users' test of 13 patients and 3 rheumatologists led to the app's current version. The number of app installations, current users and comments were collected from the Google Play store and the Apple store. RESULTS: The qualitative study revealed needs for counselling, patient-health professional partnership, and skills to cope with risk situations; 86.8% participants would be ready to use an app primarily on their rheumatologist's recommendation. Six functionalities were implemented: a safety checklist before treatment administration, aids in daily life situations based on the French academic recommendations, treatment reminders, global well-being self-assessment, periodic counselling messages, and a diary. The Hiboot app was installed 20,500 times from September 2017 to October 2020, with 4300 regular current users. Scores were 4.4/5 stars at Android and iOS stores. CONCLUSION: Hiboot is a free self-management app for patients with IA developed by a step-by-step process including patients and health professionals. Further evaluation of the Hiboot benefit is needed.

Pleistocene climate variability in eastern Africa influenced hominin evolution.

Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from ~620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (~275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10-12 (~60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens.

Impact of on-site clinical genetics consultations on diagnostic rate in children and young adults with autism spectrum disorder.

Background: Neurogenetics investigations and diagnostic yield in patients with autism spectrum disorder (ASD) have significantly improved over the last few years. Yet, many patients still fail to be systematically investigated. Methods: To improve access to services, an ambulatory team has been established since 1998, delivering on-site clinical genetics consultations and gradually upgrading services to 502 children and young adults with ASD in their standard environment across 26 day-care hospitals and specialized institutions within the Greater Paris region. The evaluation included a clinical genetics consultation, screening for fragile X syndrome, metabolic workup, chromosomal microarray analysis, and, in a proportion of patients, next-generation sequencing of genes reported in ASD and other neurodevelopmental disorders. Results: Fragile X syndrome and pathogenic copy number variants (CNVs) accounted for the disease in 10% of cases, including 4/312 (1.3%) with fragile X syndrome and 34/388 (8.8%) with pathogenic CNVs (19 de novo and 4 inherited). Importantly, adding high-throughput resequencing of reported intellectual disability/ASD genes to the screening procedure had a major impact on diagnostic yield in the 141 patients examined most recently. Pathogenic or likely pathogenic sequence variants in 27 disease genes were identified in 33/141 patients (23.4%; 23 were de novo and 10 inherited, including five X-linked and five recessive compound heterozygous variants). Diagnosed cases presented atypical and/or syndromic ASD with moderate to severe intellectual disability. The diagnostic yield of fragile X syndrome and array CGH testing combined with next-generation sequencing was significantly higher than fragile X syndrome and array CGH alone (p value 0.009). No inborn errors of metabolism were detected with the metabolic screening. Conclusion: Based on the diagnostic rate observed in this cohort, we suggest that a stepwise procedure be considered, first screening pathogenic CNVs and a limited number of disease genes in a much larger number of patients, especially those with syndromic ASD and intellectual disability.

[Twenty years of on-site clinical genetics consultations for people with ASD]. / Vingt ans de consultations de génétique clinique sur site dans les hôpitaux de jour pour les personnes atteintes de troubles du spectre autistique de la région parisienne.

Despite advances in neurogenetics of autism spectrum disorders (ASD), many patients fail to be systematically investigated, owing to preconceived ideas, limited access to genetics facilities and inadequacy of consultations to children with behavioural problems. To improve access to services, we reversed the paradigm and delivered on-site genetics consultations to ASD children of Greater Paris day care hospitals and specialized institutions. Since 1998, an ambulatory medical genetics team has been in operation, offering on-site consultations and services to patients and relatives in their usual environment. Because the mobile medical genetics unit operates under the umbrella of a university hospital, service laboratories were shared, including molecular cytogenetics and next generation sequencing (NGS). For the past 20 years, 502 patients from 26 institutions benefited from on-site consultations and genetics services in their usual environment. Less than 1 % of parents declined the offer. Previously undiagnosed genetics conditions were recognized in 71 ASD children, including pathogenic CNV variants (34/388 : 8.8 ; de novo : 19, inherited : 4), Fragile X (4/312 : 1.3 %) and deleterious variants in disease causing genes (33/141 ; 23.4 % : de novo : 23 ; inherited : 10, including 5 X-linked and 5 compound heterozygote mutations). Brain MRI were possible in 347 patients and 42 % were considered abnormal (146/347). All diagnosed patients presented atypical/syndromic ASD with moderate to severe intellectual disability. Thanks to such flexible organisation, a considerable number of missed consultations were tracked and families first benefited from medical genetics services. Owing to constraints imposed by behavioural problems in ASD, we suggest considering on-site genetics services to implement standard of care and counteract the loss of chance to patients and relatives.

TITLE: Vingt ans de consultations de génétique clinique sur site dans les hôpitaux de jour pour les personnes atteintes de troubles du spectre autistique de la région parisienne. ABSTRACT: Malgré les avancées de la recherche, un grand nombre de patients atteints de troubles du spectre autistique (TSA) n'ont pas accès aux explorations aujourd'hui disponibles, du fait d'idées reçues, de l'insuffisance des structures à même de les explorer et de l'inadaptation des consultations hospitalières à leurs troubles du comportement. Pour améliorer l'accès aux soins et au progrès des connaissances, nous avons inversé le paradigme et offrons depuis 20 ans des consultations de génétique clinique sur site dans les hôpitaux de jour et les institutions spécialisées de la région parisienne. Depuis 1998, une équipe mobile de génétique médicale propose aux patients et à leurs familles des consultations dans leur environnement habituel. L'unité mobile opère sous l'égide de l'hôpital universitaire Necker Enfants-Malades, qui leur donne accès aux services de biochimie, de cytogénétique moléculaire et de séquençage de nouvelle génération (NGS). En vingt ans, 502 patients appartenant à 26 institutions ont bénéficié de consultations sur site et d'un accès aux plateformes de génétique moléculaire. Moins de 1 % des parents ont décliné la proposition. Des affections génétiques ont été identifiées chez 71 patients présentant un TSA : anomalies cytogénétiques causales (34/388 : 8,8 % ; de novo : 19, héritées : 4), X Fragile (4/312 : 1,3 %) et mutations monogéniques reconnues responsables de TSA (33/141 ; 23,4 % : de novo : 23 ; héritées : 10, dont 5 liées à l'X et 5 récessives autosomiques). L'IRM cérébrale a été possible chez 347 patients et considérée comme anormale chez 42 % d'entre eux (146/347). Tous les patients diagnostiqués présentaient un TSA atypique ou syndromique, avec déficience intellectuelle modérée à sévère. Grâce à ce mode d'intervention, un grand nombre de consultations manquantes ont été rattrapées et les familles ont pu bénéficier d'une consultation de génétique. Eu égard aux contraintes imposées par les troubles du comportement dans les TSA, les consultations sur site constituent, pour les patients et leurs apparentés, un moyen d'améliorer l'accès aux soins et de réduire le risque de méconnaissance d'une pathologie organique à présentation psychiatrique.

Poor efficacy of TNF inhibitors in non-radiographic axial spondyloarthritis in the absence of objective signs: A bicentric retrospective study.

OBJECTIVE: To compare BASDAI 50 response rate to TNFi in axial spondyloarthritis (axSpA) depending on the presence or not of objective signs of axSpA and to look for predictive factors of TNFi efficacy. METHODS: Patients diagnosed with axSpA according to ASAS criteria "clinical arm" and treated between January 2001 and September 2015 with TNFi were included. First group included patients with at least one objective sign such as arthritis, dactylitis, enthesitis, uveitis, inflammatory bowel disease, elevated C-reactive protein or radiological sacroiliitis, and second group included non-radiographic axSpA (nr-axSpA) patients without any objective sign corresponding to patients with inflammatory back pain and either a good response to NSAID or a SpA family history. The primary outcome was the TNFi efficacy, defined as an achievement of BASDAI 50 at 3 months. The secondary outcomes were BASDAI 50 achievement over 1 year and analysis of predictive factors of TNFi response. RESULTS: We included 84 nr-axSpA patients without any objective signs and 84 axSpA patients with objective signs (48.2% r-axSpA and 52.8% nr-axSpA). BASDAI 50 achievement rates were significantly higher in patients with objective signs than in patients without, at 3 months (45.1% versus 13.7%, P<0.0001) and at any of the visit-time points over the first year (61.9% versus 21.4%, P<0.0001). In multivariate analysis, overweight/obesity and sacroiliitis on MRI were respectively negative and positive predictive factors of TNFi efficacy in the total population at 3 months (OR=0.32, 95%CI [0.11, 0.96], P=0.041 and OR=6.92, 95% CI (2.41, 19.8), P<0.0001, respectively). CONCLUSION: TNFi should be used with caution in axSpA when objective signs are absent as only 13.7% of these patients were BASDAI 50 responders at 3 months.

The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era.

Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth's surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes.

Association between diabetes mellitus and osteoarthritis: systematic literature review and meta-analysis.

OBJECTIVES: To investigate the prevalence of osteoarthritis (OA) in patients with diabetes mellitus (DM) and prevalence of DM in patients with OA and whether OA and DM are associated. DESIGN: A systematic literature review and meta-analysis. We included cohort, case-control and cross-sectional studies assessing the number of patients with DM and/or OA. The mean prevalence of OA among patients with DM and DM among patients with OA was calculated. Data from trials assessing an association of diabetes and OA were pooled and results are presented as unadjusted OR and 95% CI. RESULTS: From the 299 publications, we included 49 studies in the analysis, including 28 cross-sectional studies, 11 cohort studies and 10 case-control studies. In all, 21, 5 and 23 articles involved patients with OA exclusively, patients with DM and the general population, respectively. For 5788 patients with DM, the mean OA prevalence was 29.5±1.2%. For 645 089 patients with OA, the prevalence of DM was 14.4±0.1%. The risk of OA was greater in the DM than non-DM population (OR=1.46 (1.08 to 1.96), p=0.01), as was DM in the OA than non-OA population (OR=1.41 (1.21 to 1.65), p<0.00 001). Among the 12 studies reporting an OR adjusted on at least the body mass index, 5 showed no association of DM and OA and 7 identified DM as an independent risk factor. CONCLUSIONS: This meta-analysis highlights a high frequency of OA in patients with DM and an association between both diseases, representing a further step towards the individualisation of DM-related OA within a metabolic OA phenotype.

Association of Body Mass Index Categories with Disease Activity and Radiographic Joint Damage in Rheumatoid Arthritis: A Systematic Review and Metaanalysis.

OBJECTIVE: Obesity and overweight are increasing conditions. Adipose tissue with proinflammatory properties could be involved in rheumatoid arthritis (RA) activity and radiographic progression. This study aims to investigate the influence of overweight and obesity on RA activity and severity. METHODS: We conducted a systematic review and metaanalysis to assess the association of body mass index (BMI) categories with the Disease Activity Score in 28 joints (DAS28), functional disability [Health Assessment Questionnaire (HAQ)], and radiographic joint damage in patients with RA. We searched Medline through PubMed, EMBASE, and the Cochrane Database of Systematic Reviews for all studies assessing DAS28, HAQ, or/and radiographic damage according to predefined BMI groups. RESULTS: Among the 737 citations retrieved, 58 articles met the inclusion criteria and 7 were included in the metaanalysis. DAS28 was higher in obese (BMI > 30 kg/m(2)) than non-obese (BMI ≤ 30 kg/m(2)) patients (mean difference 0.14, 95% CI 0.01-0.27, p = 0.04, I(2) = 0%). HAQ score was also higher among obese patients (mean difference 0.10, 95% CI 0.01-0.19, p = 0.03, I(2) = 0%). Radiographic joint damage was negatively associated with obesity (standardized mean difference -0.15, 95% CI -0.29 to -0.02, p = 0.03, I(2) = 38%). CONCLUSION: Obesity in RA is associated with increased DAS28 and HAQ score and with lower radiographic joint damage. These associations mainly result from an increase of subjective components of the DAS28 (total joint count and global health assessment) in obese patients. Conflicting results were reported concerning inflammation markers (C-reactive protein and erythrocyte sedimentation rate).

Molecular and phenotypic characterization of strains nodulating Anthyllis vulneraria in mine tailings, and proposal of Aminobacter anthyllidis sp. nov., the first definition of Aminobacter as legume-nodulating bacteria.

Bacterial strains from Zn-Pb mine tailings were isolated by trapping with Anthyllis vulneraria, a legume-host suitable for mine substratum phytostabilisation. Sequence analysis of the 16S rRNA gene and three housekeeping genes (atpD, dnaK and recA) showed that they were related to those of the genus Aminobacter. DNA-DNA relatedness of representative isolates supported the placement of novel strains in Aminobacter as a new species. Phenotypic data emphasize their differentiation from the other related species of Aminobacter and Mesorhizobium. Aminobacter isolates exhibited nodA sequences tightly related with M. loti as the closest nodA relative. By contrast, their nodA sequences were highly divergent from those of M. metallidurans, another species associated with A. vulneraria that carries two complete copies of nodA. Therefore, the novel bacterial strains efficient on A. vulneraria represented the first occurrence of legume symbionts in the genus Aminobacter. They represent a new species for which the name Aminobacter anthyllidis sp. nov. is proposed (type strain STM4645(T)=LMG26462(T)=CFBP7437(T)).

Mesorhizobium metallidurans sp. nov., a metal-resistant symbiont of Anthyllis vulneraria growing on metallicolous soil in Languedoc, France.

A polyphasic taxonomic approach was used to characterize 31 rhizobial isolates obtained from Anthyllis vulneraria, a metallicolous legume species, growing close to a zinc mine in the south of France (Saint Laurent le Minier). Comparative analysis of nearly full-length 16S rRNA gene sequences showed that these Gram-negative bacteria belonged to the genus Mesorhizobium and that they were related most closely to Mesorhizobium tianshanense ORS 2640(T). The phylogenetic relationships of these isolates with other Mesorhizobium species were confirmed by sequencing and analysis of the recA and atpD genes, which were used as alternative chromosomal markers. These novel mesorhizobial strains tolerated high concentrations of heavy metals: 16-32 mM Zn and 0.3-0.5 mM Cd. DNA-DNA hybridizations revealed >73 % relatedness between the strains isolated from A. vulneraria, but only 19-33 % relatedness between these and the type strains of M. tianshanense and Mesorhizobium mediterraneum. These results, together with other phenotypic characteristics, support the conclusion that these isolates represent a single, novel species of the genus Mesorhizobium, for which the name Mesorhizobium metallidurans sp. nov. is proposed. The type strain is STM 2683(T) (=CFBP 7147(T)=LMG 24485(T)).