Quantifying hominin morphological diversity at the end of the middle Pleistocene: Implications for the origin of Homo sapiens.

OBJECTIVES: The Middle Pleistocene (MP) saw the emergence of new species of hominins: Homo sapiens in Africa, H. neanderthalensis, and possibly Denisovans in Eurasia, whose most recent common ancestor is thought to have lived in Africa around 600 ka ago. However, hominin remains from this period present a wide range of morphological variation making it difficult to securely determine their taxonomic attribution and their phylogenetic position within the Homo genus. This study proposes to reconsider the phenetic relationships between MP hominin fossils in order to clarify evolutionary trends and contacts between the populations they represent. MATERIALS AND METHODS: We used a Geometric Morphometrics approach to quantify the morphological variation of the calvarium of controversial MP specimens from Africa and Eurasia by using a comparative sample that can be divided into 5 groups: H. ergaster, H. erectus, H. neanderthalensis, and H. sapiens, as well as individuals from current modern human populations. We performed a Generalized Procrustes Analysis, a Principal Component Analysis, and Multinomial Principal Component Logistic Regressions to determine the phenetic affinities of the controversial Middle Pleistocene specimens with the other groups. RESULTS: MP African and Eurasian specimens represent several populations, some of which show strong affinities with H. neanderthalensis in Europe or H. sapiens in Africa, others presenting multiple affinities. DISCUSSION: These MP populations might have contributed to the emergence of these two species in different proportions. This study proposes a new framework for the human evolutionary history during the MP.

High-Frequency Repetitive Magnetic Stimulation Activates Bactericidal Activity of Macrophages via Modulation of p62/Keap1/Nrf2 and p38 MAPK Pathways.

The effects of repetitive magnetic stimulation (rMS) have predominantly been studied in excitable cells, with limited research in non-excitable cells. This study aimed to investigate the impact of rMS on macrophages, which are crucial cells in the innate immune defense. THP-1-derived macrophages subjected to a 5 min session of 10 Hz rMS exhibited increased Nrf2 activation and decreased Keap1 expression. We found that activation of the Nrf2 signaling pathway relied on rMS-induced phosphorylation of p62. Notably, rMS reduced the intracellular survival of Staphylococcus aureus in macrophages. Silencing Nrf2 using siRNA in THP-1-derived macrophages or utilizing Nrf2 knockout in alveolar macrophages abolished this effect. Additionally, rMS attenuated the expression of IL-1ß and TNF-α inflammatory genes by S. aureus and inhibited p38 MAPK activation. These findings highlight the capacity of rMS to activate the non-canonical Nrf2 pathway, modulate macrophage function, and enhance the host's defense against bacterial infection.

Tracking behavioral persistence and innovations during the Middle Pleistocene in Western Europe. Shift in occupations between 700 and 450 ka at la Noira site (Centre, France).

Some areas in Western Europe indicate hiatuses in human occupations, which cannot be systematically attributed to taphonomic factors and poor site preservation. The site of la Noira in the center of France records two occupation phases with a significant time gap. The older one is dated to around 700 ka (stratum a) with an Acheulean assemblage, among the earliest in Western Europe, and the upper phase of the sequence (stratum c) is dated to ca. 450 ka. Humans left the area at around 670 ka, at the beginning of the marine isotope stage (MIS) 16 glacial stage, when cold conditions became too severe. No sites between 650 and 450 ka have yet been discovered in the center region despite systematic surveys over the past three decades. The archaeological evidence indicates that populations returned to the area, at the end of MIS 12 or the beginning of the long interglacial MIS 11. Here, we use technological behaviors common to the two levels of la Noira-strata a and c to evaluate their differences. Compared to other key European sequences, this site can be used to address the evolution of the behavioral strategies in Europe between MIS 17 and 11. We formulate two hypotheses concerning the human settlement of this area: (1) local behavioral evolution over time of populations occasionally occupying the region when the climate was favorable or (2) dispersal and arrival of new populations from other areas. The results focus on (1) changes in land-use patterns with the extension of the territory used by hominins in the upper level, (2) the introduction of new core technologies, including some evidence of early Levallois debitage, and (3) more intensive shaping of bifaces and bifacial tools. Results attest that the la Noira archaeological assemblages record similar regional behavioral evolution as observed at a larger scale in Europe.

Correction to: Human behavior and Homo-mammal interactions at the first European peopling: new evidence from the Pirro Nord site (Apricena, Southern Italy).

In the original publication of this article, one of the author names was incorrectly captured. The first name should be Razika, then family name should be Chelli-Cheheb.

The Middle Pleistocene hominin mandible from Payre (Ardèche, France).

Although Neandertals are the best-known fossil hominins, the tempo and evolutionary processes in their lineage are strongly debated. This is in part due to the scarcity of the fossil record, in particular before the marine isotopic stage (MIS) 5. In 2010, a partial hominin mandible was discovered at the Middle Paleolithic site of Payre (France) in a layer that is dated to the end of MIS 8/beginning of MIS 7, a time period for which very few fossils are known in Europe. The Payre 15 mandible retains the complete symphyseal region and right lateral corpus with heavily worn P4, M1, and M2 in situ. Taphonomic modifications in the form of three notches suggest that this individual was chewed by a carnivore. We provide here the first detailed description of this specimen and a comparative analysis that includes morphological features, linear mandibular dimensions, an elliptic Fourier analysis of the symphysis, and a morphometric analysis of the M1 roots (based on segmented CT scan data). Our comparative sample encompasses European Middle and Upper Pleistocene specimens attributed to Homo heidelbergensis and Homo neanderthalensis, Upper Pleistocene Homo sapiens, and Holocene Homo sapiens. The Payre 15 mandible shows a combination of primitive and Neandertal-like features, with a receding symphyseal profile without any element of the mentum osseum, a posterior location of the mental foramen and lateral prominence. Its mandibular body is tall and thick anteriorly. Payre 15 has mesotaurodont M1 roots and a three-rooted M2. By its dimensions and combination of features, Payre 15 aligns better with Middle Pleistocene European hominins than with MIS 6-3 Neandertals. Noteworthy, it falls well within the range of variation of the Sima de los Huesos sample. Our results underscore that the total pattern of Neandertal-derived morphology was not achieved at the beginning of the MIS 7 and suggest a low level of mandibular diachronic changes for the period MIS 11-7.

Human behavior and Homo-mammal interactions at the first European peopling: new evidence from the Pirro Nord site (Apricena, Southern Italy).

Recent functional and zooarchaeological studies conducted on the archeological finds of Pirro Nord (PN13) produced new, reliable data on early European hominid subsistence activities. The age of the site is estimated to be ~ 1.3-1.6 Ma, based on bio-chronological data, and the archeological excavation of the Pirro Nord 13 fissure led to the discovery of more than 300 lithic artifacts associated with thousands of vertebrate fossil remains of the final Villafranchian (Pirro Nord Faunal Unit). The analysis of the fossil faunal remains allowed for the identification of anthropogenic traces linked to the exploitation of different animal carcass (cut marks and intentional bone breakages). Use-wear traces were also observed on some flint artifacts and have been interpreted as the result of the exploitation of animal resources by early hominids and carnivores. It has not been possible to identify the type of access that hominins developed on the carcasses, although it has been established that the hominins competed with carnivores for animal resources. The stone tools and faunal remains with anthropogenic traces recovered in the PN13 fissure represent among the earliest evidence of hominin faunal exploitation in Europe.

Isolated teeth from La Ferrassie: Reassessment of the old collections, new remains, and their implications.

OBJECTIVES: We provide the description and comparative analysis of six new teeth from the site of La Ferrassie. Our goal is to discuss their taxonomic attribution, and to provide an updated inventory of Neandertal and modern human remains from La Ferrassie in their associated archeological context. MATERIALS AND METHODS: We use external and internal anatomy, classic morphometrics, and geometric morphometrics. The teeth from La Ferrassie are compared to several samples of contemporary Neandertals and upper Paleolithic modern humans and to recent modern humans. RESULTS: Three specimens are classified as Neandertals, two as modern humans, and one remains unclassified. DISCUSSION: Based on the previously known fossil samples and the new teeth reported here, there are currently a minimum of four adult and five immature Neandertal individuals coming from the "Grand Abri" and a minimum of two modern human adult individuals: one from "Grand Abri" and one from "Grotte." It is noteworthy that the spatial distribution of the recovered Neandertal remains is not restricted to the area where the LF1-LF 8 were found but now covers the full extension of the excavated area. Moreover, while both Neandertal and modern human occupations have yielded isolated human remains, the partial-to-complete skeletons only belong to Neandertals. These considerations open new perspectives for the understanding of the occupation and use of the La Ferrassie site.

Suspected limited mobility of a Middle Pleistocene woman from Southern Italy: strontium isotopes of a human deciduous tooth.

We present the Sr isotopic composition of enamel of the most ancient deciduous tooth ever discovered in Italy to assess human mobility in Middle Pleistocene. Reconstructing ancient mobility is crucial for understanding human strategy at exploiting temporally and spatially patchy resources, with most studies focusing on indirect evidences, ultimately affecting our interpretation on hominin territoriality and energetic costs invested by hominin groups. Here, we use the high spatial resolution and micro-destructivity options offered by the Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry technique, to determine the 87Sr/ 86Sr intra-tooth variability of a human deciduous incisor from the Middle Pleistocene layers of the Isernia La Pineta site (Italy). We compared these data with the Sr isotopic signature of local micro-mammals, the broadest home-range of the macro-mammals and with modern plant samples. Our study reveals that while macro-mammals have possibly migrated through the landscape for up to 50 km, the pregnant woman from Isernia was probably local, given that the isotopic ratio of the enamel falls within the local range and is comparable with the signature of the local plants in a radius of 10 km. This is the first case study of Sr isotopic composition determination in such ancient deciduous tooth.

A Neanderthal deciduous human molar with incipient carious infection from the Middle Palaeolithic De Nadale cave, Italy.

OBJECTIVES: The aim of the study is the assessment of Nadale 1, a Neanderthal deciduous tooth recently discovered in Northeastern Italy in the De Nadale cave (Middle Palaeolithic). Together with the clear archaeological context of the site, this study brings new insight on Neanderthal behavior and dental morphological variability. MATERIALS AND METHODS: We used microCT data to provide a morphological description and morphometric analysis (diameter measurements and dental tissue volumes) of the Nadale 1 human tooth. Microwear analysis, taphonomical investigation and caries identification were performed using a stereomicroscope and Scanning Electron Microscope. RESULTS: In terms of morphology (i.e., incipient tuberculum molare, marked mesial marginal ridge and well-developed mid-trigonid crest connecting the protoconid and the metaconid, deep anterior fovea) and size, Nadale 1 presents features frequently observed in Neanderthal lower first deciduous molars. Microscope investigations reveal the presence of a small pit which could be correlated to an incipient caries. CONCLUSION: Nadale 1 expands the Italian Middle Palaeolithic fossil record and provides further information on Neanderthal dm1s in terms of dimensional and morphological variability. Furthermore, the presence of an incipient caries brings further data on Neanderthal diet.

Tooth wear pattern analysis in a sample of Italian Early Bronze Age population. Proposal of a 3-D sampling sequence.

OBJECTIVE: The purpose of this study was to assess the prevalence, distribution and intensity of tooth wear in a sample of an ancient Italian population in order to explain the pattern in terms of dietary habits and/or non-dietary tooth-use behaviors during the Early Bronze Age, with a focus on possible age-group and sex differences. DESIGN: Well-preserved permanent teeth of individuals from the Bronze Age site of Ballabio (Lecco) in northern Italy were examined for tooth wear by different methods. Eight 3D models of teeth at increasing severity of wear were created. RESULTS: In total, 357 permanent teeth belonging to male and female individuals were included in the study. Dental wear was present in 96.6% of the total sample. Males showed significantly greater levels of wear than females in the mandibular teeth. Both sexes exhibited a significantly different wear direction between the anterior (oblique and flat) and posterior (oblique and concave) teeth. Significant age differences were observed in the direction and level of wear in the incisors, canines and premolars, with higher wear in the older group. Complete and rotatable virtual 3D images of different wear patterns are proposed. CONCLUSIONS: The findings of the present study confirm the data from archaeological studies on this site and on northern Italian habits during the Early Bronze Age suggesting a diet rich in vegetables. The observed wear patterns can be related both to the diet of this Bronze age population, based on hard and abrasive food requiring vigorous mastication, and to sex differences in cultural practices.

The Hidden Conformation of Lewis x, a Human Histo-Blood Group Antigen, Is a Determinant for Recognition by Pathogen Lectins.

Histo-blood group epitopes are fucosylated branched oligosaccharides with well-defined conformations in solution that are recognized by receptors, such as lectins from pathogens. We report here the results of a series of experimental and computational endeavors revealing the unusual distortion of histo-blood group antigens by bacterial and fungal lectins. The Lewis x trisaccharide adopts a rigid closed conformation in solution, while crystallography and molecular dynamics reveal several higher energy open conformations when bound to the Ralstonia solanacearum lectin, which is in agreement with thermodynamic and kinetic measurements. Extensive molecular dynamics simulations confirm rare transient Le(x) openings in solution, frequently assisted by distortion of the central N-acetyl-glucosamine ring. Additional directed molecular dynamic trajectories revealed the role of a conserved tryptophan residue in guiding the fucose into the binding site. Our findings show that conformational adaptation of oligosaccharides is of paramount importance in cell recognition and should be considered when designing anti-infective glyco-compounds.

A Human Deciduous Tooth and New 40Ar/39Ar Dating Results from the Middle Pleistocene Archaeological Site of Isernia La Pineta, Southern Italy.

Isernia La Pineta (south-central Italy, Molise) is one of the most important archaeological localities of the Middle Pleistocene in Western Europe. It is an extensive open-air site with abundant lithic industry and faunal remains distributed across four stratified archaeosurfaces that have been found in two sectors of the excavation (3c, 3a, 3s10 in sect. I; 3a in sect. II). The prehistoric attendance was close to a wet environment, with a series of small waterfalls and lakes associated to calcareous tufa deposits. An isolated human deciduous incisor (labelled IS42) was discovered in 2014 within the archaeological level 3 coll (overlying layer 3a) that, according to new 40Ar/39Ar measurements, is dated to about 583-561 ka, i.e. to the end of marine isotope stage (MIS) 15. Thus, the tooth is currently the oldest human fossil specimen in Italy; it is an important addition to the scanty European fossil record of the Middle Pleistocene, being associated with a lithic assemblage of local raw materials (flint and limestone) characterized by the absence of handaxes and reduction strategies primarily aimed at the production of small/medium-sized flakes. The faunal assemblage is dominated by ungulates often bearing cut marks. Combining chronology with the archaeological evidence, Isernia La Pineta exhibits a delay in the appearance of handaxes with respect to other European Palaeolithic sites of the Middle Pleistocene. Interestingly, this observation matches the persistence of archaic morphological features shown by the human calvarium from the Middle Pleistocene site of Ceprano, not far from Isernia (south-central Italy, Latium). In this perspective, our analysis is aimed to evaluate morphological features occurring in IS42.

Membrane deformation by neolectins with engineered glycolipid binding sites.

Lectins are glycan-binding proteins that are involved in the recognition of glycoconjugates at the cell surface. When binding to glycolipids, multivalent lectins can affect their distribution and alter membrane shapes. Neolectins have now been designed with controlled number and position of binding sites to decipher the role of multivalency on avidity to a glycosylated surface and on membrane dynamics of glycolipids. A monomeric hexavalent neolectin has been first engineered from a trimeric hexavalent bacterial lectin, From this neolectin template, 13 different neolectins with a valency ranging from 0 to 6 were designed, produced, and analyzed for their ability to bind fucose in solution, to attach to a glycosylated surface and to invaginate glycolipid-containing giant liposomes. Whereas the avidity only depends on the presence of at least two binding sites, the ability to bend and invaginate membranes critically depends on the distance between two adjacent binding sites.

Deciphering the glycan preference of bacterial lectins by glycan array and molecular docking with validation by microcalorimetry and crystallography.

Recent advances in glycobiology revealed the essential role of lectins for deciphering the glycocode by specific recognition of carbohydrates. Integrated multiscale approaches are needed for characterizing lectin specificity: combining on one hand high-throughput analysis by glycan array experiments and systematic molecular docking of oligosaccharide libraries and on the other hand detailed analysis of the lectin/oligosaccharide interaction by x-ray crystallography, microcalorimetry and free energy calculations. The lectins LecB from Pseudomonas aeruginosa and BambL from Burkholderia ambifaria are part of the virulence factors used by the pathogenic bacteria to invade the targeted host. These two lectins are not related but both recognize fucosylated oligosaccharides such as the histo-blood group oligosaccharides of the ABH(O) and Lewis epitopes. The specificities were characterized using semi-quantitative data from glycan array and analyzed by molecular docking with the Glide software. Reliable prediction of protein/oligosaccharide structures could be obtained as validated by existing crystal structures of complexes. Additionally, the crystal structure of BambL/Lewis x was determined at 1.6 Å resolution, which confirms that Lewis x has to adopt a high-energy conformation so as to bind to this lectin. Free energies of binding were calculated using a procedure combining the Glide docking protocol followed by free energy rescoring with the Prime/Molecular Mechanics Generalized Born Surface Area (MM-GBSA) method. The calculated data were in reasonable agreement with experimental free energies of binding obtained by titration microcalorimetry. The established predictive protocol is proposed to rationalize large sets of data such as glycan arrays and to help in lead discovery projects based on such high throughput technology.

Reduction of lectin valency drastically changes glycolipid dynamics in membranes but not surface avidity.

Multivalency is proposed to play a role in the strong avidity of lectins for glycosylated cell surfaces and also in their ability to affect membrane dynamics by clustering glycosphingolipids. Lectins with modified valency were designed from the ß-propeller fold of Ralstonia solanacearum lectin (RSL) that presents six fucose binding sites. After identification of key amino acids by molecular dynamics calculations, two mutants with reduced valency were produced. Isothermal titration calorimetry confirmed the loss of three high affinity binding sites for both mutants. Crystal structures indicated that residual low affinity binding occurred in W76A but not in R17A. The trivalent R17A mutant presented unchanged avidity toward fucosylated surfaces, when compared to hexavalent RSL. However, R17A is not able anymore to induce formation of membrane invaginations on giant unilamellar vesicules, indicating the crucial role of number of binding sites for clustering of glycolipids. In the human lung epithelial cell line H1299, wt-RSL is internalized within seconds whereas the kinetics of R17A uptake is largely delayed. Neolectins with tailored valency are promising tools to study membrane dynamics.

Binding sugars: from natural lectins to synthetic receptors and engineered neolectins.

The large diversity and complexity of glycan structures together with their crucial role in many biological or pathological processes require the development of new high-throughput techniques for analyses. Lectins are classically used for characterising, imaging or targeting glycoconjugates and, when printed on microarrays, they are very useful tools for profiling glycomes. Development of recombinant lectins gives access to reliable and reproducible material, while engineering of new binding sites on existing scaffolds allows tuning of specificity. From the accumulated knowledge on protein-carbohydrate interactions, it is now possible to use nucleotide and peptide (bio)synthesis for producing new carbohydrate-binding molecules. Such a biomimetic approach can also be addressed by boron chemistry and supra-molecular chemistry for the design of fully artificial glycosensors.

Crenarchaeal CdvA forms double-helical filaments containing DNA and interacts with ESCRT-III-like CdvB.

BACKGROUND: The phylum Crenarchaeota lacks the FtsZ cell division hallmark of bacteria and employs instead Cdv proteins. While CdvB and CdvC are homologues of the eukaryotic ESCRT-III and Vps4 proteins, implicated in membrane fission processes during multivesicular body biogenesis, cytokinesis and budding of some enveloped viruses, little is known about the structure and function of CdvA. Here, we report the biochemical and biophysical characterization of the three Cdv proteins from the hyperthermophilic archaeon Metallospherae sedula. METHODOLOGY/PRINCIPAL FINDINGS: Using sucrose density gradient ultracentrifugation and negative staining electron microscopy, we evidenced for the first time that CdvA forms polymers in association with DNA, similar to known bacterial DNA partitioning proteins. We also observed that, in contrast to full-lengh CdvB that was purified as a monodisperse protein, the C-terminally deleted CdvB construct forms filamentous polymers, a phenomenon previously observed with eukaryotic ESCRT-III proteins. Based on size exclusion chromatography data combined with detection by multi-angle laser light scattering analysis, we demonstrated that CdvC assembles, in a nucleotide-independent way, as homopolymers resembling dodecamers and endowed with ATPase activity in vitro. The interactions between these putative cell division partners were further explored. Thus, besides confirming the previous observations that CdvB interacts with both CdvA and CdvC, our data demonstrate that CdvA/CdvB and CdvC/CdvB interactions are not mutually exclusive. CONCLUSIONS/SIGNIFICANCE: Our data reinforce the concept that Cdv proteins are closely related to the eukaryotic ESCRT-III counterparts and suggest that the organization of the ESCRT-III machinery at the Crenarchaeal cell division septum is organized by CdvA an ancient cytoskeleton protein that might help to coordinate genome segregation.