Mugharet el'Aliya: Affinities of an enigmatic north African Aterian maxillary fragment

Objectives

This study uses a virtual framework to examine the left maxillary fragment of the juvenile fossil from Mugharet el'Aliya, Morocco, found in association with an Aterian lithic industry. Previously, this fossil had been ascribed to modern humans or the Neanderthal lineage based on its “archaic”/“Neanderthal-like” features and apparent large size. Here, we conducted a novel 3D shape comparative analysis of the maxillary fragment to clarify its taxonomic affinities with regard to its size and ontogeny.

Materials and Methods

Eighty Computed Tomography and surface scans representing ontogenetic samples of Homo sapiens and Homo neanderthalensis were used to capture species-specific differences. The toolkit of geometric morphometrics in combination with surface registration and an elastic iterative closest point algorithm were used to create a dataset of meshes with an identical number of corresponding vertices for the maxillae. Multivariate statistics were applied to Procrustes superimposed coordinates derived from the vertices of this dataset.

Results

Our analysis showed affinities of the Mugharet el'Aliya individual with our H. sapiens sample, especially with a subadult individual from Qafzeh. No size-independent affinities with Neanderthals of comparable dental age could be identified.

Discussion

Our results add to the evidence connecting fossils from western Asia, especially Qafzeh and Skhul, and the North African Aterian. Furthermore, Mugharet el'Aliya adds to our knowledge of the ontogenetic development of adult morphology that is frequently used to characterize hominin groups, for example, Neanderthals and modern humans.     

Evaluation of Probiotic Properties of Novel Brazilian Lactiplantibacillus plantarum Strains

Probiotics and Antimicrobial Proteins - Beneficial effects of Lactiplantibacillus plantarum strains have been widely reported. Knowing that the effects of probiotic bacteria are strain-dependent,...     

The location of highly repetitious DNA in the somatic chromosomes of Drosophila melanogaster

In situ hybridization of Drosophila melanogaster somatic chromosomes has been used to demonstrate the near exact correspondence between the location of highly repetitious DNA and classically defined constitutive heterochromatin. The Y chromosome, in particular, is heavily labeled even by cRNA transcribed from female (XX) DNA templates (i.e., DNA from female Drosophila with 2 Xs and 2 sets of autosomes). This observation confirms earlier reports that the Y chromosome contains repeated DNA sequences that are shared by other chromosomes. In grain counting experiments the Y chromosome shows significantly heavier label than any other chromosome when hybridized with cRNA from XY DNA templates (i.e., DNA from male Drosophila with 1 X and 1 Y plus 2 sets of autosomes). However, the preferential labeling of the Y is abolished if the cRNA is derived from XX DNA. We interpret these results as indicating the presence of a class of Y chromosome specific repeated DNA in D. melanogaster. The relative inefficiency of the X chromosome in binding cRNA from XY and XYY DNA templates, coupled with its ability to bind XX derived cRNA, may also indicate the presence of an X chromosome specific repeated DNA.     

Self-assembly of a plant cell wall in vitro

A method has been developed by which the cell wall of Chlamydomonas reinhardi may be dissociated into its components, and then reassembled in vitro into a product that is chemically and structurally identical to the original cell wall. Chaotropic agents, such as lithium chloride and sodium perchlorate, separate the wall into two fractions, an insoluble amorphous inner wall layer, which retains its integrity (7.5% by weight of the complete wall) and a salt-soluble fraction containing the homogeneous glycoproteins responsible for the outer crystalline layers of the cell wall. Removal of the salt from dissociated walls by dialysis leads to the rapid recovery of complete reassembled cell walls. The conditions necessary for successful reconstitution of the cell wall in vitro include the presence of a suitable surface, across which a decreasing salt gradient exists, and the presence of both the salt-insoluble and the salt-soluble components. The salt-soluble glycoproteins alone can self-assemble under various conditions to form fragments that have the crystalline structure characteristic of the outer layers of the complete cell wall. Both the inner wall layer and the salt-soluble glyco-proteins have similar bulk amino acid and sugar (arabinose, galactose, mannose) compositions and both contain hydroxyproline. On the basis of the in vitro reconstitution of the cell wall we discuss certain aspects of in vivo cell wall morphogenesis. This communication describes the first case in which a plant cell wall has been reconstructed in vitro, and indicates that components of very large cellular structures are capable of being built by a simple self-assembly process.     

Alcohol:NAD oxidoreductase in brain of rats from a colony fed dilute ethanol for many generations.

—Alcohol:NAD oxidoreductase (EC 1.1.1.1) was studied in brain cortex, hypothalamus, cerebellum and midbrain of adult and immature rats, and in the whole encephalon of neonatal rats. The rats used in this study were (i) from a colony which has been given 12% (v/v) aqueous ethanol as the only fluid for 54 generations (‘E.F.’ rats); (ii) rats removed from this colony after the forty-eighth generation and thereafter fed water instead of the alcohol solution (‘E.F./H₂O’ rats); and (iii) normal rats. Enzyme activity in the 20,000 g supernatant of tissue homogenates was measured by the method of Raskin and Sokoloff. Activity was found to be highest in neonatal rat brain and to decrease as the age increased. Activity in the hypothalamus of adult E.F. rats was significantly higher than that found in the same region of adult E.F./H₂O rats. Immature rat cerebellum alcohol:NAD oxidoreductase activity was higher both in ‘E.F.’ and ‘E.F./H₂O’ suggesting a possible genetic change be involved in this CNS region. It may be concluded that, with the exception of neonatal rats, ethanol consumption induces an increase in rat CNS alcohol :NAD oxidoreductase activity.     

Cell-free propagation of prion strains

Prions are the infectious agents responsible for prion diseases, which appear to be composed exclusively by the misfolded prion protein (PrP(Sc)). Disease is transmitted by the autocatalytic propagation of PrP(Sc) misfolding at the expense of the normal prion protein. The biggest challenge of the prion hypothesis has been to explain the molecular mechanism by which prions can exist as different strains, producing diseases with distinguishable characteristics. Here, we show that PrP(Sc) generated in vitro by protein misfolding cyclic amplification from five different mouse prion strains maintains the strain-specific properties. Inoculation of wild-type mice with in vitro-generated PrP(Sc) caused a disease with indistinguishable incubation times as well as neuropathological and biochemical characteristics as the parental strains. Biochemical features were also maintained upon replication of four human prion strains. These results provide additional support for the prion hypothesis and indicate that strain characteristics can be faithfully propagated in the absence of living cells, suggesting that strain variation is dependent on PrP(Sc) properties.     

Early myocardial deformation changes associated to isolated obesity: a study based on 3D-wall motion tracking analysis

Obesity is considered as a strong risk factor for cardiovascular morbidity and mortality. 3D-wall motion tracking echocardiography (3D-WMT) provides information regarding different parameters of left ventricular (LV) myocardial deformation. Our aim was to assess the presence of early myocardial deformation abnormalities in nonselected obese children free from other cardiovascular risk factors. Thirty consecutive nonselected obese children and 42 healthy volunteer children were enrolled. None of them had any cardiovascular risk factor. Every subject underwent a 2D-echo examination and a 3D-WMT study. Mean age was 13.9 ± 2.56 and 13.25 ± 2.68 years in the nonobese and obese groups, respectively (59.7% and 40.3% male). Statistically significant differences were found for: interventricular septum thickness, LV posterior wall thickness, LV end-diastolic volume, LV end-systolic volume, left atrium volume, LV mass, and lateral annulus peak velocity. Regarding the results obtained by 3D-WMT assessment, all the evaluated parameters were statistically significantly different between the two groups. When the influence of obesity on the different echocardiographic variables was evaluated by means of multivariate logistic regression analysis, the strongest relationship with obesity was found for LV average circumferential strain (β-coefficient: 0.74; r(2): 0.55; P: 0.003). Thus, obesity cardiomyopathy is associated not only with structural cardiac changes, but also with myocardial deformation changes. Furthermore, this association occurs as early as in the childhood and it is independent from any other cardiovascular risk factor. The most related parameter to obesity is LV circumferential strain.