A practical approach to assess the native status of a rare plant species: the controverse of Buxus sempervirens L. in northern France revisited

Whether a species is native or introduced in a given geographic area is of major interest within the framewok of biological conservation. A practical approach combining phytosociological, ecological, phytogeographical and historical data is proposed to explore this status for rare plant species, and applied to Boxtree in northern France. Buxus sempervirens L. is an evergreen sub-mediterranean species whose wild populations in northern France are very rare and threatened. Its status – native or introduced – has long been be controversial. Three types of Box-woodland were found in the study area: 1) a Taxus baccata – Buxus sempervirens community which is strongly linked to post-Renaissance castles, 2) a Fraxinus excelsior–Mercurialis perennis community which may be related both to steep chalk slopes where Box was expected to be native and to Medieval castles, 3) a Quercus pubescens–Buxus sempervirens community which may be considered as an immature anthropogenic woodland. In all cases Buxus sempervirens was observed close to archaeological sites and together with exotic and/or nitrophilous plant species. Consequently Box is probably originally an introduced species in northern France and should be considered as both an archaeophyte and a feudal plant. This method offers an interesting alternative to determine the indigenity status of a rare plant species in its localities that would provide sufficiently accurate criteria in most of the cases.     

The magnetosome membrane protein, MmsF, is a major regulator of magnetite biomineralization in Magnetospirillum magneticum AMB-1

Magnetotactic bacteria (MTB) use magnetosomes, membrane-bound crystals of magnetite or greigite, for navigation along geomagnetic fields. In Magnetospirillum magneticum sp. AMB-1, and other MTB, a magnetosome gene island (MAI) is essential for every step of magnetosome formation. An 8-gene region of the MAI encodes several factors implicated in control of crystal size and morphology in previous genetic and proteomic studies. We show that these factors play a minor role in magnetite biomineralization in vivo. In contrast, MmsF, a previously uncharacterized magnetosome membrane protein encoded within the same region plays a dominant role in defining crystal size and morphology and is sufficient for restoring magnetite synthesis in the absence of the other major biomineralization candidates. In addition, we show that the 18 genes of the mamAB gene cluster of the MAI are sufficient for the formation of an immature magnetosome organelle. Addition of MmsF to these 18 genes leads to a significant enhancement of magnetite biomineralization and an increase in the cellular magnetic response. These results define a new biomineralization protein and lay down the foundation for the design of autonomous gene cassettes for the transfer of the magnetic phenotype in other bacteria.     

The neural substrates of memory suppression: a FMRI exploration of directed forgetting

The directed forgetting paradigm is frequently used to determine the ability to voluntarily suppress information. However, little is known about brain areas associated with information to forget. The present study used functional magnetic resonance imaging to determine brain activity during the encoding and retrieval phases of an item-method directed forgetting recognition task with neutral verbal material in order to apprehend all processing stages that information to forget and to remember undergoes. We hypothesized that regions supporting few selective processes, namely recollection and familiarity memory processes, working memory, inhibitory and selection processes should be differentially activated during the processing of to-be-remembered and to-be-forgotten items. Successful encoding and retrieval of items to remember engaged the entorhinal cortex, the hippocampus, the anterior medial prefrontal cortex, the left inferior parietal cortex, the posterior cingulate cortex and the precuneus; this set of regions is well known to support deep and associative encoding and retrieval processes in episodic memory. For items to forget, encoding was associated with higher activation in the right middle frontal and posterior parietal cortex, regions known to intervene in attentional control. Items to forget but nevertheless correctly recognized at retrieval yielded activation in the dorsomedial thalamus, associated with familiarity-based memory processes and in the posterior intraparietal sulcus and the anterior cingulate cortex, involved in attentional processes.     

The oldest anatomically modern humans from far southeast Europe: direct dating, culture and behavior

Background

Anatomically Modern Humans (AMHs) are known to have spread across Europe during the period coinciding with the Middle to Upper Paleolithic transition. Whereas their dispersal into Western Europe is relatively well established, evidence of an early settlement of Eastern Europe by modern humans are comparatively scarce.

Methodology/Principal Finding

Based on a multidisciplinary approach for the study of human and faunal remains, we describe here the oldest AMH remains from the extreme southeast Europe, in conjunction with their associated cultural and paleoecological background. We applied taxonomy, paleoecology, and taphonomy combined with geomorphology, stratigraphy, archeology and radiocarbon dating. More than 160 human bone remains have been discovered. They originate from a well documented Upper Paleolithic archeological layer (Gravettian cultural tradition) from the site of Buran-Kaya III located in Crimea (Ukraine). The combination of non-metric dental traits and the morphology of the occipital bones allow us to attribute the human remains to Anatomically Modern Humans. A set of human and faunal remains from this layer has been radiocarbon dated by Accelerator Mass Spectrometry. The direct-dating results of human bone establish a secure presence of AMHs at 31,900+240/−220 BP in this region. They are the oldest direct evidence of the presence of AMHs in a well documented archeological context. Based on taphonomical observations (cut marks and distribution of skeletal elements), they represent the oldest Upper Paleolithic modern humans from Eastern Europe, showing post-mortem treatment of the dead as well.

Conclusion/Significance

These findings are essential for the debate on the spread of modern humans in Europe during the Upper Paleolithic, as well as their cultural behaviors.     

Mutations in QARS,Encoding Glutaminyl-tRNA Synthetase,Cause Progressive Microcephaly,Cerebral-Cerebellar Atrophy,and Intractable Seizures

Progressive microcephaly is a heterogeneous condition with causes including mutations in genes encoding regulators of neuronal survival. Here, we report the identification of mutations in QARS (encoding glutaminyl-tRNA synthetase [QARS]) as the causative variants in two unrelated families affected by progressive microcephaly, severe seizures in infancy, atrophy of the cerebral cortex and cerebellar vermis, and mild atrophy of the cerebellar hemispheres. Whole-exome sequencing of individuals from each family independently identified compound-heterozygous mutations in QARS as the only candidate causative variants. QARS was highly expressed in the developing fetal human cerebral cortex in many cell types. The four QARS mutations altered highly conserved amino acids, and the aminoacylation activity of QARS was significantly impaired in mutant cell lines. Variants p.Gly45Val and p.Tyr57His were located in the N-terminal domain required for QARS interaction with proteins in the multisynthetase complex and potentially with glutamine tRNA, and recombinant QARS proteins bearing either substitution showed an over 10-fold reduction in aminoacylation activity. Conversely, variants p.Arg403Trp and p.Arg515Trp, each occurring in a different family, were located in the catalytic core and completely disrupted QARS aminoacylation activity in vitro. Furthermore, p.Arg403Trp and p.Arg515Trp rendered QARS less soluble, and p.Arg403Trp disrupted QARS-RARS (arginyl-tRNA synthetase 1) interaction. In zebrafish, homozygous qars loss of function caused decreased brain and eye size and extensive cell death in the brain. Our results highlight the importance of QARS during brain development and that epilepsy due to impairment of QARS activity is unusually severe in comparison to other aminoacyl-tRNA synthetase disorders.     

HMGB1 Protein Binds to Influenza Virus Nucleoprotein and Promotes Viral Replication

Influenza virus has evolved replication strategies that hijack host cell pathways. To uncover interactions between viral macromolecules and host proteins, we applied a phage display strategy. A library of human cDNA expression products displayed on filamentous phages was submitted to affinity selection for influenza viral ribonucleoproteins (vRNPs). High-mobility-group box (HMGB) proteins were found to bind to the nucleoprotein (NP) component of vRNPs. HMGB1 and HMGB2 bind directly to the purified NP in the absence of viral RNA, and the HMG box A domain is sufficient to bind the NP. We show that HMGB1 associates with the viral NP in the nuclei of infected cells, promotes viral growth, and enhances the activity of the viral polymerase. The presence of a functional HMGB1 DNA-binding site is required to enhance influenza virus replication. Glycyrrhizin, which reduces HMGB1 binding to DNA, inhibits influenza virus polymerase activity. Our data show that the HMGB1 protein can play a significant role in intranuclear replication of influenza viruses, thus extending previous findings on the bornavirus and on a number of DNA viruses.     

Application of Deamidated Gliadin Antibodies in the Follow-Up of Treated Celiac Disease

Introduction

The role of serological tests such as IgA anti-transglutaminase autoantibodies has become increasingly important in celiac disease (CD) diagnosis. However, the efficiency of these tests for patient follow-up is controversial. We investigated the correlation of 12 different serological tests, including recent deamidated gliadin and actin IgA tests, with villous atrophy (VA) in a retrospective cohort of treated celiac patients.

Materials and Methods

Serum samples were collected from 100 treated CD patients who had intestinal biopsy in the course of their follow-up. Antibodies against transglutaminase, deamidated gliadin peptides, and native gliadin were measured, along with IgA anti-actin. The biopsy slides were all blind-reviewed and scored according to Marsh classification.

Results

For all deamidated gliadin and transglutaminase tests, we found that a positive result was significantly associated with persistence of intestinal VA, with a diagnostic efficacy up to 80%. Furthermore, antibodies titers directly correlated with the degree of VA, indicating a strong link between disease activity and presence of antibodies in the serum. Interestingly, the tests with the highest association with persistent VA were those for deamidated gliadin IgG. Using a test positivity pattern analysis, we were also able to identify several groups of patients with distinct antibody profiles that showed significant differences in intestinal damage and diet compliance.

Conclusions

Altogether, these results show that deamidated gliadin antibodies are strongly correlated with VA and should be considered valuable tools in CD follow-up and that multiplex serologic analysis for treated CD represents a promising tool for personalized patient management.     

Eye Movement Deficits Are Consistent with a Staging Model of pTDP-43 Pathology in Amyotrophic Lateral Sclerosis

Background

The neuropathological process underlying amyotrophic lateral sclerosis (ALS) can be traced as a four-stage progression scheme of sequential corticofugal axonal spread. The examination of eye movement control gains deep insights into brain network pathology and provides the opportunity to detect both disturbance of the brainstem oculomotor circuitry as well as executive deficits of oculomotor function associated with higher brain networks.

Objective

To study systematically oculomotor characteristics in ALS and its underlying network pathology in order to determine whether eye movement deterioration can be categorized within a staging system of oculomotor decline that corresponds to the neuropathological model.

Methods

Sixty-eight ALS patients and 31 controls underwent video-oculographic, clinical and neuropsychological assessments.

Results

Oculomotor examinations revealed increased anti- and delayed saccades’ errors, gaze-palsy and a cerebellary type of smooth pursuit disturbance. The oculomotor disturbances occurred in a sequential manner: Stage 1, only executive control of eye movements was affected. Stage 2 indicates disturbed executive control plus ‘genuine’ oculomotor dysfunctions such as gaze-paly. We found high correlations (p<0.001) between the oculomotor stages and both, the clinical presentation as assessed by the ALS Functional Rating Scale (ALSFRS) score, and cognitive scores from the Edinburgh Cognitive and Behavioral ALS Screen (ECAS).

Conclusions

Dysfunction of eye movement control in ALS can be characterized by a two-staged sequential pattern comprising executive deficits in Stage 1 and additional impaired infratentorial oculomotor control pathways in Stage 2. This pattern parallels the neuropathological staging of ALS and may serve as a technical marker of the neuropathological spreading.     

Importance of monocytes/macrophages and fibroblasts for healing of micronecroses in porcine myocardium

In porcine heart, embolization of small coronary arteries with microspheres in 25 m in diameter induces collateral capillary vessel growth by angiogenesis in and around focal necrosis. By histological analysis the inflammatory infiltrates in this porcine tissue were characterized by numerous monocytes/macrophages and fibroblasts as well as neutrophils and numerous capillaries, some in mitosis. The aim of the present study, therefore, was to clarify the role of monocytes/macrophages and fibroblasts in angiogenesis and in repair in ischemic porcine myocardium. Using a human acidic fibroblast growth factor (aFGF) cDNA probe forin situ hybridisation labeling for aFGF mRNA was seen in monocytes and macrophages only, beginning at day 1, with a maximum at 3 and 7 days, and minimal labeling at 4 weeks. We have also shown, with a specific antibody and fluorescence microscopy, that tumur necrosis factor alpha (TNF) follows the same time sequence and that it is produced by monocytes/macrophages. The number of capillaries in infiltrates at 3 and 7 days as revealed by the lectin Dolichus Biflorus Agglutinin was high and declined at 4 weeks.In situ hybridisation using a rat cDNA probe for fibronectin showed the increased production of fibronectin mRNA in fibroblasts. To describe the expression of fibronectin and the collagens I, III, VI immunohistochemistry was used. A comparison showed that fibroblasts produced fibronectin mRNA starting at day 3, but the protein was only maximally expressed at day 7 and 4 weeks. Collagen I, III, VI expression was highest at 1–4 weeks. Conclusion: monocytes and macrophages produce the growth factors aFGF and TNF which seem to be important for angiogenesis in the ischemic myocardium. Fibroblasts, while they produce fibronectin and collagen, exert their major function in repair and scar formation, but may take also part in angiogenesis.     

An experimental test of local adaptation in soil bacteria

Abstract.— We extracted bacterial isolates of similar colony morphology from spatially located soil samples within 1 ha of old-growth forest. The same soil samples were used to prepare growth medium. Each isolate was then cultured in each medium and its growth recorded. There was no overall tendency for isolates to grow more successfully in their home site (i.e., the medium derived from the soil sample from which they had been extracted). Most isolates grew very poorly, however, and when the analysis was restricted to the minority of vigorous isolates there was clear evidence of local adaptation: isolates tended to grow better at their home site than did isolates from elsewhere and grew better at their home site than they did at other sites. The variation of growth within the 1-ha plot made up a complex fitness landscape of peaks, ridges, and valleys. Most of the vigorous isolates were found at or near a local fitness (growth) peak, although seldom at a global peak. In consequence, there was a tendency for growth to diminish away from the home site. The home isolate was about 50% more fit than average at its home site; fitness diminished exponentially away from the home site at a rate of 0.0577 per meter. These figures are similar to those previously reported for plants. This selection gradient has matched the bacterial assemblage to the edaphic structure of the environment, although the fit is far from perfect.