Direct observation of nanometer-scale pores of melittin in supported lipid monolayers.

Melittin is the most studied membrane-active peptide and archetype within a large and diverse group of pore formers. However, the molecular characteristics of melittin pores remain largely unknown. Herein, we show by atomic force microscopy (AFM) that lipid monolayers in the presence of melittin are decorated with numerous regularly shaped circular pores that can be distinguished from nonspecific monolayer defects. The specificity of these pores is reinforced through a statistical evaluation of depressions found in Langmuir-Blodgett monolayers in the presence and absence of melittin, which eventually allows characterization of the melittin-induced pores at a quantitative low-resolution level. We observed that the large majority of pores exhibit near-circular symmetry and a Gaussian distribution in size, with a mean diameter of ∼8.7 nm. A distinctive feature is a ring of material found around the pores, made by, on average, three positive peaks, with a height over the level of the lipidic background of ∼0.23 nm. This protruding rim is most likely due to the presence of melittin near the pore border. Although the current resolution of the AFM images in the {x, y} plane does not allow distinction of the specific organization of the peptide molecules, these results provide an unprecedented view of melittin pores formed in lipidic interfaces and open new perspectives for future structural investigations of these and other pore-forming peptides and proteins using supported monolayers.

Shotgun microbial profiling of fossil remains.

Millions to billions of DNA sequences can now be generated from ancient skeletal remains thanks to the massive throughput of next-generation sequencing platforms. Except in cases of exceptional endogenous DNA preservation, most of the sequences isolated from fossil material do not originate from the specimen of interest, but instead reflect environmental organisms that colonized the specimen after death. Here, we characterize the microbial diversity recovered from seven c. 200- to 13 000-year-old horse bones collected from northern Siberia. We use a robust, taxonomy-based assignment approach to identify the microorganisms present in ancient DNA extracts and quantify their relative abundance. Our results suggest that molecular preservation niches exist within ancient samples that can potentially be used to characterize the environments from which the remains are recovered. In addition, microbial community profiling of the seven specimens revealed site-specific environmental signatures. These microbial communities appear to comprise mainly organisms that colonized the fossils recently. Our approach significantly extends the amount of useful data that can be recovered from ancient specimens using a shotgun sequencing approach. In future, it may be possible to correlate, for example, the accumulation of postmortem DNA damage with the presence and/or abundance of particular microbes.

Clearing the air: Assessing healthcare professionals' awareness of air pollution's health consequences.

Air pollution (AP) significantly jeopardises health, with the Royal College of Physicians accepting the adverse effects of AP are not being sufficiently communicated to patients by healthcare professionals (HCP). To explore HCPs' understanding and attitudes toward AP and its health impacts, we conducted a service evaluation survey in a group of hospital doctors. A questionnaire comprising 20 questions about AP and its health associations was completed by 133 hospital doctors working at University Hospital Southampton NHS Foundation Trust, UK. While 65% (n = 86) of respondents strongly agreed that AP is relevant to health, 79% (n = 105) felt insufficiently trained on AP and its health associations. The survey shows that HCPs' knowledge of AP and its connection to poor health is a major barrier in discussions with patients. Further research is needed to understand whether these views are nationally shared among HCPs and to explore the most effective strategies for enhancing AP awareness.

Integrative taxonomy reveals first record of Loxoscelesrufescens (Dufour, 1820) (Araneae, Sicariidae) in the Philippines.

Background: The spider family Sicariidae Keyserling, 1880 represented by the synanthropic Mediterranean recluse spider, Loxoscelesrufescens (Dufour, 1820), is reported in the Philippines for the first time, based on morphological and molecular data. The introduced spider was observed in a small cave (Kamantigue Cave) in Lobo, Batangas Province. Considering the medical importance of this spider, the proximity of its habitat to human habitation and tourist sites poses a potential public health concern. New information: This study reports on the first record of the family Sicariidae in the Philippines and the fourth recorded occurrence of L.rufescens in Southeast Asia.

Canonical azimuthal rotations and flanking residues constrain the orientation of transmembrane helices.

In biological membranes the alignment of embedded proteins provides crucial structural information. The transmembrane (TM) parts have well-defined secondary structures, in most cases α-helices and their orientation is given by a tilt angle and an azimuthal rotation angle around the main axis. The tilt angle is readily visualized and has been found to be functionally relevant. However, there exist no general concepts on the corresponding azimuthal rotation. Here, we show that TM helices prefer discrete rotation angles. They arise from a combination of intrinsic properties of the helix geometry plus the influence of the position and type of flanking residues at both ends of the hydrophobic core. The helical geometry gives rise to canonical azimuthal angles for which the side chains of residues from the two ends of the TM helix tend to have maximum or minimum immersion within the membrane. This affects the preferential position of residues that fall near hydrophobic/polar interfaces of the membrane, depending on their hydrophobicity and capacity to form specific anchoring interactions. On this basis, we can explain the orientation and dynamics of TM helices and make accurate predictions, which correspond well to the experimental values of several model peptides (including dimers), and TM segments of polytopic membrane proteins.

Prescriptive behavior of non-vitamin K oral anticoagulants in patients affected by atrial fibrillation in general practice.

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and in recent years the pharmacological approach has been strongly implemented; in Italy, the prescription of the non-vitamin K oral anticoagulants (NOAC) was also extended to General Practitioners (GPs) since 2020. The aim of the present study was to investigate the GPs prescribing behaviour of NOACs. An observational study was performed by using the computerized medical record of 14 GPs in Sicily: patients affected by AF were selected and stratified according to the prescribed antithrombotic drugs. Patients were considered inadequately managed if antithrombotic treatment was not adherent to recent ESC guidelines. A total of 467 (2.7 %) patients were affected by AF, 276 (59.1 %) were treated with an oral anticoagulant (OAC) regardless the high stroke risk (OR 1.64; 95 %CI 0.74-3.62; p = 0.226). The NOAC users were 236 patients as follow: Rivaroxaban 33.5 %, Apixaban 33,1 %, Dabigatran 17,4 %, Edoxaban 16.1 %. In 7 patients an inappropriate NOAC treatment was observed. Among Vitamin-K antagonist users, 25.0 % were considered inappropriate. Patients not treated with OAC were 191, of them 81.7 % were at high stroke risk and did not receive any OAC despite the indication to treat. In addition, the probability to be not properly managed significantly increased in older and in patients with atherosclerosis. Conversely, patients with at least one reported cardiology counselling significantly reduced the likelihood to be not properly managed (OR 0.38, 95 %CI 0.25-0.58; p 0.01). Our results suggest the need to optimize the management of real-life AF patients by improving prescribing adherence to ESC guidelines.

DNA from soil mirrors plant taxonomic and growth form diversity.

Ecosystems across the globe are threatened by climate change and human activities. New rapid survey approaches for monitoring biodiversity would greatly advance assessment and understanding of these threats. Taking advantage of next-generation DNA sequencing, we tested an approach we call metabarcoding: high-throughput and simultaneous taxa identification based on a very short (usually <100 base pairs) but informative DNA fragment. Short DNA fragments allow the use of degraded DNA from environmental samples. All analyses included amplification using plant-specific versatile primers, sequencing and estimation of taxonomic diversity. We tested in three steps whether degraded DNA from dead material in soil has the potential of efficiently assessing biodiversity in different biomes. First, soil DNA from eight boreal plant communities located in two different vegetation types (meadow and heath) was amplified. Plant diversity detected from boreal soil was highly consistent with plant taxonomic and growth form diversity estimated from conventional above-ground surveys. Second, we assessed DNA persistence using samples from formerly cultivated soils in temperate environments. We found that the number of crop DNA sequences retrieved strongly varied with years since last cultivation, and crop sequences were absent from nearby, uncultivated plots. Third, we assessed the universal applicability of DNA metabarcoding using soil samples from tropical environments: a large proportion of species and families from the study site were efficiently recovered. The results open unprecedented opportunities for large-scale DNA-based biodiversity studies across a range of taxonomic groups using standardized metabarcoding approaches.

Switchable bactericidal effects from novel silica-coated silver nanoparticles mediated by light irradiation.

Here we report on the triggering of antibacterial activity by a new type of silver nanoparticle coated with porous silica, Ag@silica, irradiated at their surface plasmon resonant frequency. The nanoparticles are able to bind readily to the surface of bacterial cells, although this does not affect bacterial growth since the silica shell largely attenuates the intrinsic toxicity of silver. However, upon simultaneous exposure to light corresponding to the absorption band of the nanoparticles, bacterial death is enhanced selectively on the irradiated zone. Because of the low power density used for the treatments, we discard thermal effects as the cause of cell killing. Instead, we propose that the increase in toxicity is due to the enhanced electromagnetic field in the proximity of the nanoparticles, which indirectly, most likely through induced photochemical reactions, is able to cause cell death.

A lipocentric view of peptide-induced pores.

Although lipid membranes serve as effective sealing barriers for the passage of most polar solutes, nonmediated leakage is not completely improbable. A high activation energy normally keeps unassisted bilayer permeation at a very low frequency, but lipids are able to self-organize as pores even in peptide-free and protein-free membranes. The probability of leakage phenomena increases under conditions such as phase coexistence, external stress or perturbation associated to binding of nonlipidic molecules. Here, we argue that pore formation can be viewed as an intrinsic property of lipid bilayers, with strong similarities in the structure and mechanism between pores formed with participation of peptides, lipidic pores induced by different types of stress, and spontaneous transient bilayer defects driven by thermal fluctuations. Within such a lipocentric framework, amphipathic peptides are best described as pore-inducing rather than pore-forming elements. Active peptides bound to membranes can be understood as a source of internal surface tension which facilitates pore formation by diminishing the high activation energy barrier. This first or immediate action of the peptide has some resemblance to catalysis. However, the presence of membrane-active peptides has the additional effect of displacing the equilibrium towards the pore-open state, which is then maintained over long times, and reducing the size of initial individual pores. Thus, pore-inducing peptides, regardless of their sequence and oligomeric organization, can be assigned a double role of increasing the probability of pore formation in membranes to high levels as well as stabilizing these pores after they appear.

Pores formed by Baxα5 relax to a smaller size and keep at equilibrium.

Pores made by amphipathic cationic peptides (e.g., antimicrobials and fragments of pore-forming proteins) are typically studied by examining the kinetics of vesicle leakage after peptide addition or obtaining structural measurements in reconstituted peptide-lipid systems. In the first case, the pores have been considered transient phenomena that allow the relaxation of the peptide-membrane system. In the second, they correspond to equilibrium structures at minimum free energy. Here we reconcile both approaches by investigating the pore activity of the α5 fragment from the proapoptotic protein Bax (Baxα5) before and after equilibrium of peptide/vesicle complexes. Quenching assays on suspensions of large unilamellar vesicles suggest that in the presence of Baxα5, the vesicles maintain a leaky state for hours under equilibrium conditions. We proved and analyzed stable pores on single giant unilamellar vesicles (GUVs) in detail by monitoring the entrance of dyes added at different times after incubation with the peptide. When the GUVs came in contact with Baxα5, leakage started stochastically, was delayed for various periods of time, and in the majority of cases proceeded rapidly to completion. After hours in the presence of the peptide, the same individual GUVs that refilled completely at first instance maintained a porated state, which could be observed in subsequent leak-in events for serially added dyes. However, these long-term pores were smaller in size than the initial equilibration pores. Stable pores were also detected in GUVs made in the presence of Baxα5. The latter pores can be considered equilibrium states and may correspond to structures measured previously in bilayer stacks. Although pore formation may occur as a kinetic process, equilibrium pores may also be functionally relevant structures, especially in highly regulated systems such as the apoptotic mitochondrial pores induced by Bax.

PET-CT scan positive pulmonary nodule revealing histoplasmosis: a case report.

Our medical staff identified a case of a forty-six years old Armed Force active duty female that presented with multiple systemic and pulmonary signs and symptoms, such as hemoptysis, arthralgias, chest pain and dyspnea after being exposed to a humid and old wooden building one year ago in the state of Georgia. Various imaging studies (cervical & thoracic x-rays and CT Scans), revealed diffuse small nodules at cervical & thoracic areas, osteolytic lesions and lymphadenopathy. Suspecting a malignant process, a PET-CT Scan was performed revealing a right lung lower lobe nodule consistent with a primary malignancy, metastatic disease, active infectious or inflammatory process. She underwent a CT-guided needle biopsy followed by an open thoracotomy. These results were negative for malignancy and positive for chronic granulomatous inflammatory process. Therefore, special immunologic stains were undertaken revealing a granulomatous process with Histoplasmosis capsulatum. This case was diagnosed in the most unusual manner, given the presenting symptoms and pathological findings which suggested a malignant process, later confirmed by multiple specialized imaging studies and tests. This presumptive diagnosis turned out to be an inflammatory/infectious (fungal) process. We must keep in mind that not all mass lesions encountered by special imaging studies should be considered malignant. This case exemplifies the need of clinicians to exercise strong clinical and critical thinking skills to consider the broad diagnostic possibilities of pulmonary nodules presenting as a malignancy.

Side effects of cyclosporine-A treatment in rats: gingival overgrowth and early hyperglycemia.

Gingival overgrowth is an adverse side effect of cyclosporine A (CsA) in the treatment of transplanted patients. The purpose of this study was to evaluate the effects of CsA on new-onset diabetes mellitus and gingival overgrowth in rats, by measuring collagen, nitric oxide and microvascular permeability. Blood glucose level, collagen, nitric oxide level and vascular permeability were determined. Blood glucose level increased significantly from 6.5 +/- 0.9 for the control group to 15 +/- 1.2, 17 +/- 1.2 and 21.6 +/- 1.6 mM/L at 1, 4 or 8 weeks of CsA treatment, respectively. Collagen (ug HO Proline/mg p) increased significantly from 2.5 +/- 0.5 for the control group to 4.2 +/- 0.8, 5.9 +/- 0.6 and 7.3 +/- 0.8 at 1, 4 or 8 weeks of CsA treatment, respectively. Vascular permeability was 10.3 +/- 1.2 for the control group and 15 +/- 1; 17.2 +/- 1.3, and 22.1 +/- 2.1 ug EB/g T; at 1, 4 or 8 weeks of CsA treatment, respectively Nitric oxide level was 3.5 +/- .9 umol/mg P for the control group and 4 +/- 0.2, 8.2 +/- 0.9 and 11 +/- 1 for 1, 2 or 8 weeks of CsA treatment, respectively. These findings appear to indicate that the development of significant gingival changes induced by CsA is related to new-onset of diabetes mellitus during the immunosuppressive treatment.

Adjuvant endocrine treatment in premenopausal early breast cancer.

The impact of endocrine therapies in the adjuvant treatment of premenopausal patients with early breast cancer is well established. However, the right combination and duration of endocrine manipulations currently available (luteinizing hormone-releasing hormone analogs and tamoxifen) remain unclear. Moreover, the role of chemotherapy in addition to endocrine therapies is not clearly defined. The most recent Early Breast Cancer Trialists' Collaborative Group overview has confirmed the efficacy of five years of tamoxifen in reducing the annual recurrence rate and the annual breast cancer death rate by 41 and 34%, respectively, in an estrogen receptor-positive population. These results are largely irrespective of age, use of chemotherapy or other tumor features. Moreover, the expert panel of the St. Gallen Conference accepted both tamoxifen or tamoxifen plus ovarian suppression as standard endocrine therapy for premenopausal breast cancer patients with endocrine-responsive disease. The use of ovarian suppression or ablation also significantly reduced the risk of breast cancer-related death, mainly in the absence of other systemic therapies. Chemotherapy is widely used in this population; however, its role in endocrine-positive premenopausal women with hormone-positive disease treated with optimal endocrine therapy remains unclear.

Stable-bond polymeric reversed-phase/weak anion-exchange mixed-mode stationary phases obtained by simultaneous functionalization and crosslinking of a poly(3-mercaptopropyl)methylsiloxane-film on vinyl silica via thiol-ene double click reaction.

A polymeric reversed-phase/weak anion exchange (Poly-RP/WAX) mixed-mode stationary phase has been prepared by coating of a poly(3-mercaptopropyl)methylsiloxane film on vinyl-modified silica (100 Å, 5 µm) and simultaneous in situ functionalization with N-(10-undecenoyl)-3-aminoquinuclidine as well as crosslinking to the vinyl silica surface by solventless thiol-ene double click reaction. Such bonding chemistry showed greatly enhanced stability compared to brush-type analogs with bifunctional siloxane bonding to silica. Solid-state 29Si-CP/MAS NMR confirmed the immobilization of the siloxane layer. pH-Dependent ζ-potential determinations revealed a high anion-exchange capacity over the entire pH range with a maximum around pH 5. Oxidation of residual thiols yielded a zwitterionic Poly-RP/WAX/SCX mixed-mode phase with sulfonic acid endcapping and shifted the still net positive surface charge to lower ζ-potentials. It allowed a faster elution of strongly retained anionic species in particular of multiply negatively charged analytes such as oligonucleotides. Chromatographic tests under RPLC and HILIC elution mode with various test substances documented the multimodal utility and complementarity in retention profiles compared to RP, HILIC and commercial mixed-mode phases.

Preoperative bevacizumab combined with letrozole and chemotherapy in locally advanced ER- and/or PgR-positive breast cancer: clinical and biological activity.

The antiangiogenic agent bevacizumab showed synergistic effects when combined with chemotherapy in advanced breast cancer. We presently investigated the activity of bevacizumab in combination with chemotherapy, including capecitabine and vinorelbine, and endocrine therapy, including letrozole (+triptorelin in premenopausal women), as primary therapy for patients with ER and/or PgR > or =10% T2-T4a-c, N0-N2, M0 breast cancer. Biological end point included the proliferative activity (Ki67), whereas clinical end points were clinical response rate, pathological complete response (pCR) and tolerability. Circulating endothelial cells (CECs) and their progenitors, as surrogate markers of antiangiogenic activity, were measured at baseline and at surgery.Thirty-six women are evaluable. A clinical response rate of 86% (95% CI, 70-95) and no pCR were observed; Ki67 was significantly decreased by 71% (interquartile range, -82%, -62%). Toxicity was manageable: two grade 3 hypertension, four grade 3 deep venous thrombosis and no grade >2 proteinuria were observed. Treatment significantly decreased the percentage of viable CECs and prevented the chemotherapy-induced mobilisation of circulating progenitors. Basal circulating progenitors were positively associated with clinical response. In conclusion, bevacizumab is feasible and active in association with primary chemoendocrine therapy for ER-positive tumours in terms of proliferation inhibition, clinical response and antiangiogenic activity.

N-Propyl-N'-2-pyridylurea-modified silica as mixed-mode stationary phase with moderate weak anion exchange capacity and pH-dependent surface charge reversal.

Herein, we present a novel silica-based stationary phase modified with N-propyl-N'-2-pyridylurea selector. Due to the weakly basic properties of the pyridine selector and the presence of residual silanols after selector immobilization, a zwitterionic surface with a pI observed at approximately pH 5.5 was measured by electrophoretic light scattering in pH-dependent ζ-potential determinations. The capability of the new N-propyl-N'-2-pyridylurea-modified silica to serve as mixed-mode stationary phase was investigated. For this purpose, it was characterized under RP and HILIC conditions using test mixtures. Subsequent classification of this stationary phase in comparison to in-house and commercial benchmarks was carried by principal component analysis of resultant retention factors from chromatographic tests. The results show a relatively unique mixed-mode character amongst the tested stationary phases. The chromatographic retention characteristics of acidic compounds matched well the ζ-potential determinations. The application of anion-exchange at low pH values (e.g. pH 5) and ion exclusion chromatography at pH 7 for the separation of uridine 5'-mono-, di- and triphosphate demonstrated a pH-dependent umpolung of the stationary phase surface. The combination of these separation principles in a pH gradient from 5 to 7 gave rise to weak anion-exchange selectivity with a charge-inducted elution due to repulsive interactions at higher pH and resulted in a significant faster separation with improved peak shape under mild elution conditions.

The effect of gingival aging in diabetic and non-diabetic status: an experimental study.

Major gingival-periodontal changes according to age have been observed in both diabetic and non-diabetic rats. Male Wistar rats weighing 200-220 g were divided into two groups: 1) Nondiabetic (ND) and 2) Diabetic (D) by receiving an intraperitoneal (ip) dose of streptozotocin (STZ) (50 mg /kg). Animals from both groups (ND and D) were euthanized at 4, 8, 12, 17 y 25 weeks after treatment with saline solution or STZ. Glycemia values in ND rats were 5 to 6 mmol/L, while in D, glycemia increased progressively between weeks 4 and 25, with values ranging from 18. 3±2. 1 to 39. 3±2. 7 mmol/L. Oxidative stress differed significantly in gums of ND and D rats. ND: lipid peroxidation: Malondialdehyde (MDA): 8. 52±1. 2 to 15. 5±2(nmol/mgP); superoxide dismutase (SOD): 37. 1±4. 2 to 21. 2±1. 3 (U/100mgP); D: MDA 13. 1±1. 6 to 22. 9±2. 7 (nmol/L); superoxide dismutase (SOD): 17. 7±0. 8 to 9. ±0. 2 (U/100mgP). Vascular permeability (VP) and gingival edema (E) showed significant changes between ND and D rats from 4 to 25 weeks. ND: PV: 10±0. 2 to 16. 1±1. 3 (EB ug/g dry t); E: 0. 9±0. 1 to 4. 1±1. 3 ml; D: PV: 12±1. 2 to 24. 4±1. 6 (EB ug/g dry t); E: 2. 2±0. 2 to 8. 4±1. 3 ml. Aging produced progressive natural changes in oxidative stress, VP and gingival E. In diabetic animals, changes in oxidative stress, VP and gingival E were observed early and were progressively more significant than for ND. According to these results, non-diabetic gingival modifications develop naturally with age, while in aging associated to diabetic disease, hyperglycemia increases progressively and early.

Se han observados importantes cambios gingivo-periodontales en función de la edad tanto en ratas no diabéticas como en ratas diabéticas. Ratas machos Wistar de 200-220 g de peso corporal fueron separadas en dos grupos: 1) No diabéticas(ND) ; 2) Diabéticas (D), por haber recibido una dosis intraperitoneal (ip) de estreptozotocina (STZ) (50 mg íkg). Ambos grupos de ratas (ND y D) fueron sacrificados a las 4, 8, 12, 17 y 25 semanas de edad después del tratamiento con solución salina o con STZ. En ratas ND las los valores de glucemia fueron de 5 a 6 mmol/L, en tanto que en las D las glucemias se observaron progresivamente aumentadas entre las 4 y las 25 semanas con valores entre 18. 3±2. 1 a 39. 3±2. 7 mmol/L. El estrés oxidativo mostró diferencias significativas entre las encías de animales ND respecto a los D; ND: peroxidacion lipidica: Malondihaldeido (MDA): 8. 52±1. 2 a 15. 5±2(nmol/mgP);superoxido dismutasa (SOD):37. 1±4. 2 a 21. 2±1. 3 (U/100mgP); D : MDA 13. 1±1. 6 a 22. 9±2. 7 (nmol/L); Superoxidodismutasa :SOD 17. 7±0. 8 a 9. ±0. 2 (U/100mgP). La permeabilidad vascular(PV) y el edema(E) gingival mostraron cambios significativos entre las 4 y las 25 semanas de edad entre los animales ND respecto a los D : ND : PV: 10±0. 2 a 16. 1±1. 3 (EB ug/g t seco); E :0. 9±0. 1 a 4. 1±1. 3 ml; D: PV :12±1. 2 a 24. 4±1. 6 (EB ug/g t seco); E 2. 2_/- 0. 2 a 8. 4± 1. 3 ml. El envejecimiento produjo cambios progresivos naturales en el estrés oxidativo, PV y Egingival. En tanto que en el estado diabético los cambios del estrés oxidativo, PV y E gingival se observan temprano y fueron progresivamente más significativos comparados con los ND. De acuerdo a estos resultados las modificaciones gingivales no diabéticas se desarrollan naturalmente en función de la edad, en cambio en la senectud asociada con enfermedad diabética la hiperglucemia aumenta progresiva y tempranamente.

Ancient DNA analysis reveals divergence of the cave bear, Ursus spelaeus, and brown bear, Ursus arctos, lineages.

The cave bear, Ursus spelaeus, represents one of the most frequently found paleontological remains from the Pleistocene in Europe. The species has always been confined to Europe and was contemporary with the brown bear, Ursus arctos. Relationships between the cave bear and the two lineages of brown bears defined in Europe, as well as the origins of the two species, remain controversial, mainly due to the wide morphological diversity of the fossil remains, which makes interpretation difficult [1, 2]. Sequence analysis of ancient DNA is a useful tool for resolving such problems because it provides an independent source of data [3]. We previously amplified a short DNA fragment of the mitochondrial DNA control region (mt control region) of a 40,000-year-old Ursus spelaeus sample [4]. In this paper, we describe the DNA analysis of two mtDNA regions, the control region and the cytochrome b gene. Control region sequences were obtained from ten samples of cave bears ranging from 130,000 to 20,000 years BP, and one particularly well-conserved sample gave a complete cyt b sequence. Our data demonstrate that cave bears split largely before the lineages of brown bears around 1.2 million years ago. Given its abundance, its wide distribution in space and time, and its large morphological diversity, the cave bear is a promising model for direct observation of the evolution of sequences throughout time, extinction periods, and the differentiation of populations shaped by climatic fluctuations during the Pleistocene.

Detecting taxonomic and phylogenetic signals in equid cheek teeth: towards new palaeontological and archaeological proxies.

The Plio-Pleistocene evolution of Equus and the subsequent domestication of horses and donkeys remains poorly understood, due to the lack of phenotypic markers capable of tracing this evolutionary process in the palaeontological/archaeological record. Using images from 345 specimens, encompassing 15 extant taxa of equids, we quantified the occlusal enamel folding pattern in four mandibular cheek teeth with a single geometric morphometric protocol. We initially investigated the protocol accuracy by assigning each tooth to its correct anatomical position and taxonomic group. We then contrasted the phylogenetic signal present in each tooth shape with an exome-wide phylogeny from 10 extant equine species. We estimated the strength of the phylogenetic signal using a Brownian motion model of evolution with multivariate K statistic, and mapped the dental shape along the molecular phylogeny using an approach based on squared-change parsimony. We found clear evidence for the relevance of dental phenotypes to accurately discriminate all modern members of the genus Equus and capture their phylogenetic relationships. These results are valuable for both palaeontologists and zooarchaeologists exploring the spatial and temporal dynamics of the evolutionary history of the horse family, up to the latest domestication trajectories of horses and donkeys.

Surface-anchored counterions on weak chiral anion-exchangers accelerate separations and improve their compatibility for mass-spectrometry-hyphenation.

In the present work we propose new variants of chiral stationary phases (CSP) with tert-butylcarbamoylquinine (tBuCQN) as chiral selector molecule. Four tBuCQN-CSPs with distinct bonding chemistries are compared in terms of their pH-dependent surface charge by ζ-potential determinations, by achiral and chiral liquid chromatographic tests and LC-ESI-MS hyphenation. In one embodiment tBuCQN was immobilized on 3-mercaptopropylmethylsilyl-modified silica by thiol-ene click reaction (brush type CSP with selector coverage of 0.38mmol/g). In another embodiment, poly-(3-mercaptopropyl)-methylsiloxane was coated onto vinylized silica particles in presence of tBuCQN and radical initiator. The tBuCQN selector was then immobilized onto the polysiloxane film which in turn was crosslinked to the vinyl-surface in a simultaneous double click reaction leading to a CSP with enhanced stability due to multiple linkages (0.29mmol/g tBuCQN). Aliquots of each of the two CSPs were further modified by oxidation of free residual thiol groups to sulfonic acid functionalities to obtain strongly acidic endcapping groups which act as immobilized counterions of the chiral WAX CSPs (0.2mmol/g sulfonic acid co-ligands for brush type CSP). This caused secondary repulsive interactions, hence balanced interactions of the target analytes (chiral acids) at the WAX site and decreased non-specific interactions. Furthermore, this rendered possible the use of milder elution conditions, i.e. lower ionic strength, for acidic compounds. Separation performance was maintained and slightly improved, respectively, when using polar organic or reversed-phase type elution mode in chiral separations which were significantly accelerated (isoeluotropic conditions could be achieved with ca. factor 40 lower counterion concentration in the mobile phase). Thus, LC-ESI-MS enantiomer separations could be readily performed at very low ionic strength conditions (10mM acetate) which is favorable due to less ion suppression. In addition to this the newly developed stationary phases showed complementary retention profiles in RP- and HILIC-mode which make these type of stationary phases also promising tools for achiral applications in pharmaceutical analysis, especially as orthogonal separation principle e.g. in 2D-LC and impurity profiling.